text: //===-- LLParser.cpp - Parser Class ---------------------------------------===//
  //
  // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
  // See https://llvm.org/LICENSE.txt for license information.
  // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
  //
  //===----------------------------------------------------------------------===//
  //
  //  This file defines the parser class for .ll files.
  //
  //===----------------------------------------------------------------------===//
  
  #include "llvm/AsmParser/LLParser.h"
  #include "llvm/ADT/APSInt.h"
  #include "llvm/ADT/DenseMap.h"
  #include "llvm/ADT/None.h"
  #include "llvm/ADT/STLExtras.h"
  #include "llvm/ADT/SmallPtrSet.h"
  #include "llvm/AsmParser/LLToken.h"
  #include "llvm/AsmParser/SlotMapping.h"
  #include "llvm/BinaryFormat/Dwarf.h"
  #include "llvm/IR/Argument.h"
  #include "llvm/IR/AutoUpgrade.h"
  #include "llvm/IR/BasicBlock.h"
  #include "llvm/IR/CallingConv.h"
  #include "llvm/IR/Comdat.h"
  #include "llvm/IR/ConstantRange.h"
  #include "llvm/IR/Constants.h"
  #include "llvm/IR/DebugInfoMetadata.h"
  #include "llvm/IR/DerivedTypes.h"
  #include "llvm/IR/Function.h"
  #include "llvm/IR/GlobalIFunc.h"
  #include "llvm/IR/GlobalObject.h"
  #include "llvm/IR/InlineAsm.h"
  #include "llvm/IR/Instructions.h"
  #include "llvm/IR/Intrinsics.h"
  #include "llvm/IR/LLVMContext.h"
  #include "llvm/IR/Metadata.h"
  #include "llvm/IR/Module.h"
  #include "llvm/IR/Value.h"
  #include "llvm/IR/ValueSymbolTable.h"
  #include "llvm/Support/Casting.h"
  #include "llvm/Support/ErrorHandling.h"
  #include "llvm/Support/MathExtras.h"
  #include "llvm/Support/SaveAndRestore.h"
  #include "llvm/Support/raw_ostream.h"
  #include <algorithm>
  #include <cassert>
  #include <cstring>
  #include <iterator>
  #include <vector>
  
  using namespace llvm;
  
  static std::string getTypeString(Type *T) {
    std::string Result;
    raw_string_ostream Tmp(Result);
    Tmp << *T;
    return Tmp.str();
  }
  
  /// Run: module ::= toplevelentity*
  bool LLParser::Run(bool UpgradeDebugInfo,
                     DataLayoutCallbackTy DataLayoutCallback) {
    // Prime the lexer.
    Lex.Lex();
  
    if (Context.shouldDiscardValueNames())
      return error(
          Lex.getLoc(),
          "Can't read textual IR with a Context that discards named Values");
  
    if (M) {
      if (parseTargetDefinitions())
        return true;
  
      if (auto LayoutOverride = DataLayoutCallback(M->getTargetTriple()))
        M->setDataLayout(*LayoutOverride);
    }
  
    return parseTopLevelEntities() || validateEndOfModule(UpgradeDebugInfo) ||
           validateEndOfIndex();
  }
  
  bool LLParser::parseStandaloneConstantValue(Constant *&C,
                                              const SlotMapping *Slots) {
    restoreParsingState(Slots);
    Lex.Lex();
  
    Type *Ty = nullptr;
    if (parseType(Ty) || parseConstantValue(Ty, C))
      return true;
    if (Lex.getKind() != lltok::Eof)
      return error(Lex.getLoc(), "expected end of string");
    return false;
  }
  
  bool LLParser::parseTypeAtBeginning(Type *&Ty, unsigned &Read,
                                      const SlotMapping *Slots) {
    restoreParsingState(Slots);
    Lex.Lex();
  
    Read = 0;
    SMLoc Start = Lex.getLoc();
    Ty = nullptr;
    if (parseType(Ty))
      return true;
    SMLoc End = Lex.getLoc();
    Read = End.getPointer() - Start.getPointer();
  
    return false;
  }
  
  void LLParser::restoreParsingState(const SlotMapping *Slots) {
    if (!Slots)
      return;
    NumberedVals = Slots->GlobalValues;
    NumberedMetadata = Slots->MetadataNodes;
    for (const auto &I : Slots->NamedTypes)
      NamedTypes.insert(
          std::make_pair(I.getKey(), std::make_pair(I.second, LocTy())));
    for (const auto &I : Slots->Types)
      NumberedTypes.insert(
          std::make_pair(I.first, std::make_pair(I.second, LocTy())));
  }
  
  /// validateEndOfModule - Do final validity and basic correctness checks at the
  /// end of the module.
  bool LLParser::validateEndOfModule(bool UpgradeDebugInfo) {
    if (!M)
      return false;
    // Handle any function attribute group forward references.
    for (const auto &RAG : ForwardRefAttrGroups) {
      Value *V = RAG.first;
      const std::vector<unsigned> &Attrs = RAG.second;
      AttrBuilder B;
  
      for (const auto &Attr : Attrs)
        B.merge(NumberedAttrBuilders[Attr]);
  
      if (Function *Fn = dyn_cast<Function>(V)) {
        AttributeList AS = Fn->getAttributes();
        AttrBuilder FnAttrs(AS.getFnAttrs());
        AS = AS.removeFnAttributes(Context);
  
        FnAttrs.merge(B);
  
        // If the alignment was parsed as an attribute, move to the alignment
        // field.
        if (FnAttrs.hasAlignmentAttr()) {
          Fn->setAlignment(FnAttrs.getAlignment());
          FnAttrs.removeAttribute(Attribute::Alignment);
        }
  
        AS = AS.addFnAttributes(Context, AttributeSet::get(Context, FnAttrs));
        Fn->setAttributes(AS);
      } else if (CallInst *CI = dyn_cast<CallInst>(V)) {
        AttributeList AS = CI->getAttributes();
        AttrBuilder FnAttrs(AS.getFnAttrs());
        AS = AS.removeFnAttributes(Context);
        FnAttrs.merge(B);
        AS = AS.addFnAttributes(Context, AttributeSet::get(Context, FnAttrs));
        CI->setAttributes(AS);
      } else if (InvokeInst *II = dyn_cast<InvokeInst>(V)) {
        AttributeList AS = II->getAttributes();
        AttrBuilder FnAttrs(AS.getFnAttrs());
        AS = AS.removeFnAttributes(Context);
        FnAttrs.merge(B);
        AS = AS.addFnAttributes(Context, AttributeSet::get(Context, FnAttrs));
        II->setAttributes(AS);
      } else if (CallBrInst *CBI = dyn_cast<CallBrInst>(V)) {
        AttributeList AS = CBI->getAttributes();
        AttrBuilder FnAttrs(AS.getFnAttrs());
        AS = AS.removeFnAttributes(Context);
        FnAttrs.merge(B);
        AS = AS.addFnAttributes(Context, AttributeSet::get(Context, FnAttrs));
        CBI->setAttributes(AS);
      } else if (auto *GV = dyn_cast<GlobalVariable>(V)) {
        AttrBuilder Attrs(GV->getAttributes());
        Attrs.merge(B);
        GV->setAttributes(AttributeSet::get(Context,Attrs));
      } else {
        llvm_unreachable("invalid object with forward attribute group reference");
      }
    }
  
    // If there are entries in ForwardRefBlockAddresses at this point, the
    // function was never defined.
    if (!ForwardRefBlockAddresses.empty())
      return error(ForwardRefBlockAddresses.begin()->first.Loc,
                   "expected function name in blockaddress");
  
    for (const auto &NT : NumberedTypes)
      if (NT.second.second.isValid())
        return error(NT.second.second,
                     "use of undefined type '%" + Twine(NT.first) + "'");
  
    for (StringMap<std::pair<Type*, LocTy> >::iterator I =
         NamedTypes.begin(), E = NamedTypes.end(); I != E; ++I)
      if (I->second.second.isValid())
        return error(I->second.second,
                     "use of undefined type named '" + I->getKey() + "'");
  
    if (!ForwardRefComdats.empty())
      return error(ForwardRefComdats.begin()->second,
                   "use of undefined comdat '$" +
                       ForwardRefComdats.begin()->first + "'");
  
    if (!ForwardRefVals.empty())
      return error(ForwardRefVals.begin()->second.second,
                   "use of undefined value '@" + ForwardRefVals.begin()->first +
                       "'");
  
    if (!ForwardRefValIDs.empty())
      return error(ForwardRefValIDs.begin()->second.second,
                   "use of undefined value '@" +
                       Twine(ForwardRefValIDs.begin()->first) + "'");
  
    if (!ForwardRefMDNodes.empty())
      return error(ForwardRefMDNodes.begin()->second.second,
                   "use of undefined metadata '!" +
                       Twine(ForwardRefMDNodes.begin()->first) + "'");
  
    // Resolve metadata cycles.
    for (auto &N : NumberedMetadata) {
      if (N.second && !N.second->isResolved())
        N.second->resolveCycles();
    }
  
    for (auto *Inst : InstsWithTBAATag) {
      MDNode *MD = Inst->getMetadata(LLVMContext::MD_tbaa);
      assert(MD && "UpgradeInstWithTBAATag should have a TBAA tag");
      auto *UpgradedMD = UpgradeTBAANode(*MD);
      if (MD != UpgradedMD)
        Inst->setMetadata(LLVMContext::MD_tbaa, UpgradedMD);
    }
  
    // Look for intrinsic functions and CallInst that need to be upgraded.  We use
    // make_early_inc_range here because we may remove some functions.
    for (Function &F : llvm::make_early_inc_range(*M))
      UpgradeCallsToIntrinsic(&F);
  
    // Some types could be renamed during loading if several modules are
    // loaded in the same LLVMContext (LTO scenario). In this case we should
    // remangle intrinsics names as well.
    for (Function &F : llvm::make_early_inc_range(*M)) {
      if (auto Remangled = Intrinsic::remangleIntrinsicFunction(&F)) {
        F.replaceAllUsesWith(Remangled.getValue());
        F.eraseFromParent();
      }
    }
  
    if (UpgradeDebugInfo)
      llvm::UpgradeDebugInfo(*M);
  
    UpgradeModuleFlags(*M);
    UpgradeSectionAttributes(*M);
  
    if (!Slots)
      return false;
    // Initialize the slot mapping.
    // Because by this point we've parsed and validated everything, we can "steal"
    // the mapping from LLParser as it doesn't need it anymore.
    Slots->GlobalValues = std::move(NumberedVals);
    Slots->MetadataNodes = std::move(NumberedMetadata);
    for (const auto &I : NamedTypes)
      Slots->NamedTypes.insert(std::make_pair(I.getKey(), I.second.first));
    for (const auto &I : NumberedTypes)
      Slots->Types.insert(std::make_pair(I.first, I.second.first));
  
    return false;
  }
  
  /// Do final validity and basic correctness checks at the end of the index.
  bool LLParser::validateEndOfIndex() {
    if (!Index)
      return false;
  
    if (!ForwardRefValueInfos.empty())
      return error(ForwardRefValueInfos.begin()->second.front().second,
                   "use of undefined summary '^" +
                       Twine(ForwardRefValueInfos.begin()->first) + "'");
  
    if (!ForwardRefAliasees.empty())
      return error(ForwardRefAliasees.begin()->second.front().second,
                   "use of undefined summary '^" +
                       Twine(ForwardRefAliasees.begin()->first) + "'");
  
    if (!ForwardRefTypeIds.empty())
      return error(ForwardRefTypeIds.begin()->second.front().second,
                   "use of undefined type id summary '^" +
                       Twine(ForwardRefTypeIds.begin()->first) + "'");
  
    return false;
  }
  
  //===----------------------------------------------------------------------===//
  // Top-Level Entities
  //===----------------------------------------------------------------------===//
  
  bool LLParser::parseTargetDefinitions() {
    while (true) {
      switch (Lex.getKind()) {
      case lltok::kw_target:
        if (parseTargetDefinition())
          return true;
        break;
      case lltok::kw_source_filename:
        if (parseSourceFileName())
          return true;
        break;
      default:
        return false;
      }
    }
  }
  
  bool LLParser::parseTopLevelEntities() {
    // If there is no Module, then parse just the summary index entries.
    if (!M) {
      while (true) {
        switch (Lex.getKind()) {
        case lltok::Eof:
          return false;
        case lltok::SummaryID:
          if (parseSummaryEntry())
            return true;
          break;
        case lltok::kw_source_filename:
          if (parseSourceFileName())
            return true;
          break;
        default:
          // Skip everything else
          Lex.Lex();
        }
      }
    }
    while (true) {
      switch (Lex.getKind()) {
      default:
        return tokError("expected top-level entity");
      case lltok::Eof: return false;
      case lltok::kw_declare:
        if (parseDeclare())
          return true;
        break;
      case lltok::kw_define:
        if (parseDefine())
          return true;
        break;
      case lltok::kw_module:
        if (parseModuleAsm())
          return true;
        break;
      case lltok::LocalVarID:
        if (parseUnnamedType())
          return true;
        break;
      case lltok::LocalVar:
        if (parseNamedType())
          return true;
        break;
      case lltok::GlobalID:
        if (parseUnnamedGlobal())
          return true;
        break;
      case lltok::GlobalVar:
        if (parseNamedGlobal())
          return true;
        break;
      case lltok::ComdatVar:  if (parseComdat()) return true; break;
      case lltok::exclaim:
        if (parseStandaloneMetadata())
          return true;
        break;
      case lltok::SummaryID:
        if (parseSummaryEntry())
          return true;
        break;
      case lltok::MetadataVar:
        if (parseNamedMetadata())
          return true;
        break;
      case lltok::kw_attributes:
        if (parseUnnamedAttrGrp())
          return true;
        break;
      case lltok::kw_uselistorder:
        if (parseUseListOrder())
          return true;
        break;
      case lltok::kw_uselistorder_bb:
        if (parseUseListOrderBB())
          return true;
        break;
      }
    }
  }
  
  /// toplevelentity
  ///   ::= 'module' 'asm' STRINGCONSTANT
  bool LLParser::parseModuleAsm() {
    assert(Lex.getKind() == lltok::kw_module);
    Lex.Lex();
  
    std::string AsmStr;
    if (parseToken(lltok::kw_asm, "expected 'module asm'") ||
        parseStringConstant(AsmStr))
      return true;
  
    M->appendModuleInlineAsm(AsmStr);
    return false;
  }
  
  /// toplevelentity
  ///   ::= 'target' 'triple' '=' STRINGCONSTANT
  ///   ::= 'target' 'datalayout' '=' STRINGCONSTANT
  bool LLParser::parseTargetDefinition() {
    assert(Lex.getKind() == lltok::kw_target);
    std::string Str;
    switch (Lex.Lex()) {
    default:
      return tokError("unknown target property");
    case lltok::kw_triple:
      Lex.Lex();
      if (parseToken(lltok::equal, "expected '=' after target triple") ||
          parseStringConstant(Str))
        return true;
      M->setTargetTriple(Str);
      return false;
    case lltok::kw_datalayout:
      Lex.Lex();
      if (parseToken(lltok::equal, "expected '=' after target datalayout") ||
          parseStringConstant(Str))
        return true;
      M->setDataLayout(Str);
      return false;
    }
  }
  
  /// toplevelentity
  ///   ::= 'source_filename' '=' STRINGCONSTANT
  bool LLParser::parseSourceFileName() {
    assert(Lex.getKind() == lltok::kw_source_filename);
    Lex.Lex();
    if (parseToken(lltok::equal, "expected '=' after source_filename") ||
        parseStringConstant(SourceFileName))
      return true;
    if (M)
      M->setSourceFileName(SourceFileName);
    return false;
  }
  
  /// parseUnnamedType:
  ///   ::= LocalVarID '=' 'type' type
  bool LLParser::parseUnnamedType() {
    LocTy TypeLoc = Lex.getLoc();
    unsigned TypeID = Lex.getUIntVal();
    Lex.Lex(); // eat LocalVarID;
  
    if (parseToken(lltok::equal, "expected '=' after name") ||
        parseToken(lltok::kw_type, "expected 'type' after '='"))
      return true;
  
    Type *Result = nullptr;
    if (parseStructDefinition(TypeLoc, "", NumberedTypes[TypeID], Result))
      return true;
  
    if (!isa<StructType>(Result)) {
      std::pair<Type*, LocTy> &Entry = NumberedTypes[TypeID];
      if (Entry.first)
        return error(TypeLoc, "non-struct types may not be recursive");
      Entry.first = Result;
      Entry.second = SMLoc();
    }
  
    return false;
  }
  
  /// toplevelentity
  ///   ::= LocalVar '=' 'type' type
  bool LLParser::parseNamedType() {
    std::string Name = Lex.getStrVal();
    LocTy NameLoc = Lex.getLoc();
    Lex.Lex();  // eat LocalVar.
  
    if (parseToken(lltok::equal, "expected '=' after name") ||
        parseToken(lltok::kw_type, "expected 'type' after name"))
      return true;
  
    Type *Result = nullptr;
    if (parseStructDefinition(NameLoc, Name, NamedTypes[Name], Result))
      return true;
  
    if (!isa<StructType>(Result)) {
      std::pair<Type*, LocTy> &Entry = NamedTypes[Name];
      if (Entry.first)
        return error(NameLoc, "non-struct types may not be recursive");
      Entry.first = Result;
      Entry.second = SMLoc();
    }
  
    return false;
  }
  
  /// toplevelentity
  ///   ::= 'declare' FunctionHeader
  bool LLParser::parseDeclare() {
    assert(Lex.getKind() == lltok::kw_declare);
    Lex.Lex();
  
    std::vector<std::pair<unsigned, MDNode *>> MDs;
    while (Lex.getKind() == lltok::MetadataVar) {
      unsigned MDK;
      MDNode *N;
      if (parseMetadataAttachment(MDK, N))
        return true;
      MDs.push_back({MDK, N});
    }
  
    Function *F;
    if (parseFunctionHeader(F, false))
      return true;
    for (auto &MD : MDs)
      F->addMetadata(MD.first, *MD.second);
    return false;
  }
  
  /// toplevelentity
  ///   ::= 'define' FunctionHeader (!dbg !56)* '{' ...
  bool LLParser::parseDefine() {
    assert(Lex.getKind() == lltok::kw_define);
    Lex.Lex();
  
    Function *F;
    return parseFunctionHeader(F, true) || parseOptionalFunctionMetadata(*F) ||
           parseFunctionBody(*F);
  }
  
  /// parseGlobalType
  ///   ::= 'constant'
  ///   ::= 'global'
  bool LLParser::parseGlobalType(bool &IsConstant) {
    if (Lex.getKind() == lltok::kw_constant)
      IsConstant = true;
    else if (Lex.getKind() == lltok::kw_global)
      IsConstant = false;
    else {
      IsConstant = false;
      return tokError("expected 'global' or 'constant'");
    }
    Lex.Lex();
    return false;
  }
  
  bool LLParser::parseOptionalUnnamedAddr(
      GlobalVariable::UnnamedAddr &UnnamedAddr) {
    if (EatIfPresent(lltok::kw_unnamed_addr))
      UnnamedAddr = GlobalValue::UnnamedAddr::Global;
    else if (EatIfPresent(lltok::kw_local_unnamed_addr))
      UnnamedAddr = GlobalValue::UnnamedAddr::Local;
    else
      UnnamedAddr = GlobalValue::UnnamedAddr::None;
    return false;
  }
  
  /// parseUnnamedGlobal:
  ///   OptionalVisibility (ALIAS | IFUNC) ...
  ///   OptionalLinkage OptionalPreemptionSpecifier OptionalVisibility
  ///   OptionalDLLStorageClass
  ///                                                     ...   -> global variable
  ///   GlobalID '=' OptionalVisibility (ALIAS | IFUNC) ...
  ///   GlobalID '=' OptionalLinkage OptionalPreemptionSpecifier
  ///   OptionalVisibility
  ///                OptionalDLLStorageClass
  ///                                                     ...   -> global variable
  bool LLParser::parseUnnamedGlobal() {
    unsigned VarID = NumberedVals.size();
    std::string Name;
    LocTy NameLoc = Lex.getLoc();
  
    // Handle the GlobalID form.
    if (Lex.getKind() == lltok::GlobalID) {
      if (Lex.getUIntVal() != VarID)
        return error(Lex.getLoc(),
                     "variable expected to be numbered '%" + Twine(VarID) + "'");
      Lex.Lex(); // eat GlobalID;
  
      if (parseToken(lltok::equal, "expected '=' after name"))
        return true;
    }
  
    bool HasLinkage;
    unsigned Linkage, Visibility, DLLStorageClass;
    bool DSOLocal;
    GlobalVariable::ThreadLocalMode TLM;
    GlobalVariable::UnnamedAddr UnnamedAddr;
    if (parseOptionalLinkage(Linkage, HasLinkage, Visibility, DLLStorageClass,
                             DSOLocal) ||
        parseOptionalThreadLocal(TLM) || parseOptionalUnnamedAddr(UnnamedAddr))
      return true;
  
    switch (Lex.getKind()) {
    default:
      return parseGlobal(Name, NameLoc, Linkage, HasLinkage, Visibility,
                         DLLStorageClass, DSOLocal, TLM, UnnamedAddr);
    case lltok::kw_alias:
    case lltok::kw_ifunc:
      return parseAliasOrIFunc(Name, NameLoc, Linkage, Visibility,
                               DLLStorageClass, DSOLocal, TLM, UnnamedAddr);
    }
  }
  
  /// parseNamedGlobal:
  ///   GlobalVar '=' OptionalVisibility (ALIAS | IFUNC) ...
  ///   GlobalVar '=' OptionalLinkage OptionalPreemptionSpecifier
  ///                 OptionalVisibility OptionalDLLStorageClass
  ///                                                     ...   -> global variable
  bool LLParser::parseNamedGlobal() {
    assert(Lex.getKind() == lltok::GlobalVar);
    LocTy NameLoc = Lex.getLoc();
    std::string Name = Lex.getStrVal();
    Lex.Lex();
  
    bool HasLinkage;
    unsigned Linkage, Visibility, DLLStorageClass;
    bool DSOLocal;
    GlobalVariable::ThreadLocalMode TLM;
    GlobalVariable::UnnamedAddr UnnamedAddr;
    if (parseToken(lltok::equal, "expected '=' in global variable") ||
        parseOptionalLinkage(Linkage, HasLinkage, Visibility, DLLStorageClass,
                             DSOLocal) ||
        parseOptionalThreadLocal(TLM) || parseOptionalUnnamedAddr(UnnamedAddr))
      return true;
  
    switch (Lex.getKind()) {
    default:
      return parseGlobal(Name, NameLoc, Linkage, HasLinkage, Visibility,
                         DLLStorageClass, DSOLocal, TLM, UnnamedAddr);
    case lltok::kw_alias:
    case lltok::kw_ifunc:
      return parseAliasOrIFunc(Name, NameLoc, Linkage, Visibility,
                               DLLStorageClass, DSOLocal, TLM, UnnamedAddr);
    }
  }
  
  bool LLParser::parseComdat() {
    assert(Lex.getKind() == lltok::ComdatVar);
    std::string Name = Lex.getStrVal();
    LocTy NameLoc = Lex.getLoc();
    Lex.Lex();
  
    if (parseToken(lltok::equal, "expected '=' here"))
      return true;
  
    if (parseToken(lltok::kw_comdat, "expected comdat keyword"))
      return tokError("expected comdat type");
  
    Comdat::SelectionKind SK;
    switch (Lex.getKind()) {
    default:
      return tokError("unknown selection kind");
    case lltok::kw_any:
      SK = Comdat::Any;
      break;
    case lltok::kw_exactmatch:
      SK = Comdat::ExactMatch;
      break;
    case lltok::kw_largest:
      SK = Comdat::Largest;
      break;
    case lltok::kw_nodeduplicate:
      SK = Comdat::NoDeduplicate;
      break;
    case lltok::kw_samesize:
      SK = Comdat::SameSize;
      break;
    }
    Lex.Lex();
  
    // See if the comdat was forward referenced, if so, use the comdat.
    Module::ComdatSymTabType &ComdatSymTab = M->getComdatSymbolTable();
    Module::ComdatSymTabType::iterator I = ComdatSymTab.find(Name);
    if (I != ComdatSymTab.end() && !ForwardRefComdats.erase(Name))
      return error(NameLoc, "redefinition of comdat '$" + Name + "'");
  
    Comdat *C;
    if (I != ComdatSymTab.end())
      C = &I->second;
    else
      C = M->getOrInsertComdat(Name);
    C->setSelectionKind(SK);
  
    return false;
  }
  
  // MDString:
  //   ::= '!' STRINGCONSTANT
  bool LLParser::parseMDString(MDString *&Result) {
    std::string Str;
    if (parseStringConstant(Str))
      return true;
    Result = MDString::get(Context, Str);
    return false;
  }
  
  // MDNode:
  //   ::= '!' MDNodeNumber
  bool LLParser::parseMDNodeID(MDNode *&Result) {
    // !{ ..., !42, ... }
    LocTy IDLoc = Lex.getLoc();
    unsigned MID = 0;
    if (parseUInt32(MID))
      return true;
  
    // If not a forward reference, just return it now.
    if (NumberedMetadata.count(MID)) {
      Result = NumberedMetadata[MID];
      return false;
    }
  
    // Otherwise, create MDNode forward reference.
    auto &FwdRef = ForwardRefMDNodes[MID];
    FwdRef = std::make_pair(MDTuple::getTemporary(Context, None), IDLoc);
  
    Result = FwdRef.first.get();
    NumberedMetadata[MID].reset(Result);
    return false;
  }
  
  /// parseNamedMetadata:
  ///   !foo = !{ !1, !2 }
  bool LLParser::parseNamedMetadata() {
    assert(Lex.getKind() == lltok::MetadataVar);
    std::string Name = Lex.getStrVal();
    Lex.Lex();
  
    if (parseToken(lltok::equal, "expected '=' here") ||
        parseToken(lltok::exclaim, "Expected '!' here") ||
        parseToken(lltok::lbrace, "Expected '{' here"))
      return true;
  
    NamedMDNode *NMD = M->getOrInsertNamedMetadata(Name);
    if (Lex.getKind() != lltok::rbrace)
      do {
        MDNode *N = nullptr;
        // parse DIExpressions inline as a special case. They are still MDNodes,
        // so they can still appear in named metadata. Remove this logic if they
        // become plain Metadata.
        if (Lex.getKind() == lltok::MetadataVar &&
            Lex.getStrVal() == "DIExpression") {
          if (parseDIExpression(N, /*IsDistinct=*/false))
            return true;
          // DIArgLists should only appear inline in a function, as they may
          // contain LocalAsMetadata arguments which require a function context.
        } else if (Lex.getKind() == lltok::MetadataVar &&
                   Lex.getStrVal() == "DIArgList") {
          return tokError("found DIArgList outside of function");
        } else if (parseToken(lltok::exclaim, "Expected '!' here") ||
                   parseMDNodeID(N)) {
          return true;
        }
        NMD->addOperand(N);
      } while (EatIfPresent(lltok::comma));
  
    return parseToken(lltok::rbrace, "expected end of metadata node");
  }
  
  /// parseStandaloneMetadata:
  ///   !42 = !{...}
  bool LLParser::parseStandaloneMetadata() {
    assert(Lex.getKind() == lltok::exclaim);
    Lex.Lex();
    unsigned MetadataID = 0;
  
    MDNode *Init;
    if (parseUInt32(MetadataID) || parseToken(lltok::equal, "expected '=' here"))
      return true;
  
    // Detect common error, from old metadata syntax.
    if (Lex.getKind() == lltok::Type)
      return tokError("unexpected type in metadata definition");
  
    bool IsDistinct = EatIfPresent(lltok::kw_distinct);
    if (Lex.getKind() == lltok::MetadataVar) {
      if (parseSpecializedMDNode(Init, IsDistinct))
        return true;
    } else if (parseToken(lltok::exclaim, "Expected '!' here") ||
               parseMDTuple(Init, IsDistinct))
      return true;
  
    // See if this was forward referenced, if so, handle it.
    auto FI = ForwardRefMDNodes.find(MetadataID);
    if (FI != ForwardRefMDNodes.end()) {
      FI->second.first->replaceAllUsesWith(Init);
      ForwardRefMDNodes.erase(FI);
  
      assert(NumberedMetadata[MetadataID] == Init && "Tracking VH didn't work");
    } else {
      if (NumberedMetadata.count(MetadataID))
        return tokError("Metadata id is already used");
      NumberedMetadata[MetadataID].reset(Init);
    }
  
    return false;
  }
  
  // Skips a single module summary entry.
  bool LLParser::skipModuleSummaryEntry() {
    // Each module summary entry consists of a tag for the entry
    // type, followed by a colon, then the fields which may be surrounded by
    // nested sets of parentheses. The "tag:" looks like a Label. Once parsing
    // support is in place we will look for the tokens corresponding to the
    // expected tags.
    if (Lex.getKind() != lltok::kw_gv && Lex.getKind() != lltok::kw_module &&
        Lex.getKind() != lltok::kw_typeid && Lex.getKind() != lltok::kw_flags &&
        Lex.getKind() != lltok::kw_blockcount)
      return tokError(
          "Expected 'gv', 'module', 'typeid', 'flags' or 'blockcount' at the "
          "start of summary entry");
    if (Lex.getKind() == lltok::kw_flags)
      return parseSummaryIndexFlags();
    if (Lex.getKind() == lltok::kw_blockcount)
      return parseBlockCount();
    Lex.Lex();
    if (parseToken(lltok::colon, "expected ':' at start of summary entry") ||
        parseToken(lltok::lparen, "expected '(' at start of summary entry"))
      return true;
    // Now walk through the parenthesized entry, until the number of open
    // parentheses goes back down to 0 (the first '(' was parsed above).
    unsigned NumOpenParen = 1;
    do {
      switch (Lex.getKind()) {
      case lltok::lparen:
        NumOpenParen++;
        break;
      case lltok::rparen:
        NumOpenParen--;
        break;
      case lltok::Eof:
        return tokError("found end of file while parsing summary entry");
      default:
        // Skip everything in between parentheses.
        break;
      }
      Lex.Lex();
    } while (NumOpenParen > 0);
    return false;
  }
  
  /// SummaryEntry
  ///   ::= SummaryID '=' GVEntry | ModuleEntry | TypeIdEntry
  bool LLParser::parseSummaryEntry() {
    assert(Lex.getKind() == lltok::SummaryID);
    unsigned SummaryID = Lex.getUIntVal();
  
    // For summary entries, colons should be treated as distinct tokens,
    // not an indication of the end of a label token.
    Lex.setIgnoreColonInIdentifiers(true);
  
    Lex.Lex();
    if (parseToken(lltok::equal, "expected '=' here"))
      return true;
  
    // If we don't have an index object, skip the summary entry.
    if (!Index)
      return skipModuleSummaryEntry();
  
    bool result = false;
    switch (Lex.getKind()) {
    case lltok::kw_gv:
      result = parseGVEntry(SummaryID);
      break;
    case lltok::kw_module:
      result = parseModuleEntry(SummaryID);
      break;
    case lltok::kw_typeid:
      result = parseTypeIdEntry(SummaryID);
      break;
    case lltok::kw_typeidCompatibleVTable:
      result = parseTypeIdCompatibleVtableEntry(SummaryID);
      break;
    case lltok::kw_flags:
      result = parseSummaryIndexFlags();
      break;
    case lltok::kw_blockcount:
      result = parseBlockCount();
      break;
    default:
      result = error(Lex.getLoc(), "unexpected summary kind");
      break;
    }
    Lex.setIgnoreColonInIdentifiers(false);
    return result;
  }
  
  static bool isValidVisibilityForLinkage(unsigned V, unsigned L) {
    return !GlobalValue::isLocalLinkage((GlobalValue::LinkageTypes)L) ||
           (GlobalValue::VisibilityTypes)V == GlobalValue::DefaultVisibility;
  }
  
  // If there was an explicit dso_local, update GV. In the absence of an explicit
  // dso_local we keep the default value.
  static void maybeSetDSOLocal(bool DSOLocal, GlobalValue &GV) {
    if (DSOLocal)
      GV.setDSOLocal(true);
  }
  
  static std::string typeComparisonErrorMessage(StringRef Message, Type *Ty1,
                                                Type *Ty2) {
    std::string ErrString;
    raw_string_ostream ErrOS(ErrString);
    ErrOS << Message << " (" << *Ty1 << " vs " << *Ty2 << ")";
    return ErrOS.str();
  }
  
  /// parseAliasOrIFunc:
  ///   ::= GlobalVar '=' OptionalLinkage OptionalPreemptionSpecifier
  ///                     OptionalVisibility OptionalDLLStorageClass
  ///                     OptionalThreadLocal OptionalUnnamedAddr
  ///                     'alias|ifunc' AliaseeOrResolver SymbolAttrs*
  ///
  /// AliaseeOrResolver
  ///   ::= TypeAndValue
  ///
  /// SymbolAttrs
  ///   ::= ',' 'partition' StringConstant
  ///
  /// Everything through OptionalUnnamedAddr has already been parsed.
  ///
  bool LLParser::parseAliasOrIFunc(const std::string &Name, LocTy NameLoc,
                                   unsigned L, unsigned Visibility,
                                   unsigned DLLStorageClass, bool DSOLocal,
                                   GlobalVariable::ThreadLocalMode TLM,
                                   GlobalVariable::UnnamedAddr UnnamedAddr) {
    bool IsAlias;
    if (Lex.getKind() == lltok::kw_alias)
      IsAlias = true;
    else if (Lex.getKind() == lltok::kw_ifunc)
      IsAlias = false;
    else
      llvm_unreachable("Not an alias or ifunc!");
    Lex.Lex();
  
    GlobalValue::LinkageTypes Linkage = (GlobalValue::LinkageTypes) L;
  
    if(IsAlias && !GlobalAlias::isValidLinkage(Linkage))
      return error(NameLoc, "invalid linkage type for alias");
  
    if (!isValidVisibilityForLinkage(Visibility, L))
      return error(NameLoc,
                   "symbol with local linkage must have default visibility");
  
    Type *Ty;
    LocTy ExplicitTypeLoc = Lex.getLoc();
    if (parseType(Ty) ||
        parseToken(lltok::comma, "expected comma after alias or ifunc's type"))
      return true;
  
    Constant *Aliasee;
    LocTy AliaseeLoc = Lex.getLoc();
    if (Lex.getKind() != lltok::kw_bitcast &&
        Lex.getKind() != lltok::kw_getelementptr &&
        Lex.getKind() != lltok::kw_addrspacecast &&
        Lex.getKind() != lltok::kw_inttoptr) {
      if (parseGlobalTypeAndValue(Aliasee))
        return true;
    } else {
      // The bitcast dest type is not present, it is implied by the dest type.
      ValID ID;
      if (parseValID(ID, /*PFS=*/nullptr))
        return true;
      if (ID.Kind != ValID::t_Constant)
        return error(AliaseeLoc, "invalid aliasee");
      Aliasee = ID.ConstantVal;
    }
  
    Type *AliaseeType = Aliasee->getType();
    auto *PTy = dyn_cast<PointerType>(AliaseeType);
    if (!PTy)
      return error(AliaseeLoc, "An alias or ifunc must have pointer type");
    unsigned AddrSpace = PTy->getAddressSpace();
  
    if (IsAlias && !PTy->isOpaqueOrPointeeTypeMatches(Ty)) {
      return error(
          ExplicitTypeLoc,
          typeComparisonErrorMessage(
              "explicit pointee type doesn't match operand's pointee type", Ty,
              PTy->getElementType()));
    }
  
    if (!IsAlias && !PTy->getElementType()->isFunctionTy()) {
      return error(ExplicitTypeLoc,
                   "explicit pointee type should be a function type");
    }
  
    GlobalValue *GVal = nullptr;
  
    // See if the alias was forward referenced, if so, prepare to replace the
    // forward reference.
    if (!Name.empty()) {
      auto I = ForwardRefVals.find(Name);
      if (I != ForwardRefVals.end()) {
        GVal = I->second.first;
        ForwardRefVals.erase(Name);
      } else if (M->getNamedValue(Name)) {
        return error(NameLoc, "redefinition of global '@" + Name + "'");
      }
    } else {
      auto I = ForwardRefValIDs.find(NumberedVals.size());
      if (I != ForwardRefValIDs.end()) {
        GVal = I->second.first;
        ForwardRefValIDs.erase(I);
      }
    }
  
    // Okay, create the alias/ifunc but do not insert it into the module yet.
    std::unique_ptr<GlobalAlias> GA;
    std::unique_ptr<GlobalIFunc> GI;
    GlobalValue *GV;
    if (IsAlias) {
      GA.reset(GlobalAlias::create(Ty, AddrSpace,
                                   (GlobalValue::LinkageTypes)Linkage, Name,
                                   Aliasee, /*Parent*/ nullptr));
      GV = GA.get();
    } else {
      GI.reset(GlobalIFunc::create(Ty, AddrSpace,
                                   (GlobalValue::LinkageTypes)Linkage, Name,
                                   Aliasee, /*Parent*/ nullptr));
      GV = GI.get();
    }
    GV->setThreadLocalMode(TLM);
    GV->setVisibility((GlobalValue::VisibilityTypes)Visibility);
    GV->setDLLStorageClass((GlobalValue::DLLStorageClassTypes)DLLStorageClass);
    GV->setUnnamedAddr(UnnamedAddr);
    maybeSetDSOLocal(DSOLocal, *GV);
  
    // At this point we've parsed everything except for the IndirectSymbolAttrs.
    // Now parse them if there are any.
    while (Lex.getKind() == lltok::comma) {
      Lex.Lex();
  
      if (Lex.getKind() == lltok::kw_partition) {
        Lex.Lex();
        GV->setPartition(Lex.getStrVal());
        if (parseToken(lltok::StringConstant, "expected partition string"))
          return true;
      } else {
        return tokError("unknown alias or ifunc property!");
      }
    }
  
    if (Name.empty())
      NumberedVals.push_back(GV);
  
    if (GVal) {
      // Verify that types agree.
      if (GVal->getType() != GV->getType())
        return error(
            ExplicitTypeLoc,
            "forward reference and definition of alias have different types");
  
      // If they agree, just RAUW the old value with the alias and remove the
      // forward ref info.
      GVal->replaceAllUsesWith(GV);
      GVal->eraseFromParent();
    }
  
    // Insert into the module, we know its name won't collide now.
    if (IsAlias)
      M->getAliasList().push_back(GA.release());
    else
      M->getIFuncList().push_back(GI.release());
    assert(GV->getName() == Name && "Should not be a name conflict!");
  
    return false;
  }
  
  /// parseGlobal
  ///   ::= GlobalVar '=' OptionalLinkage OptionalPreemptionSpecifier
  ///       OptionalVisibility OptionalDLLStorageClass
  ///       OptionalThreadLocal OptionalUnnamedAddr OptionalAddrSpace
  ///       OptionalExternallyInitialized GlobalType Type Const OptionalAttrs
  ///   ::= OptionalLinkage OptionalPreemptionSpecifier OptionalVisibility
  ///       OptionalDLLStorageClass OptionalThreadLocal OptionalUnnamedAddr
  ///       OptionalAddrSpace OptionalExternallyInitialized GlobalType Type
  ///       Const OptionalAttrs
  ///
  /// Everything up to and including OptionalUnnamedAddr has been parsed
  /// already.
  ///
  bool LLParser::parseGlobal(const std::string &Name, LocTy NameLoc,
                             unsigned Linkage, bool HasLinkage,
                             unsigned Visibility, unsigned DLLStorageClass,
                             bool DSOLocal, GlobalVariable::ThreadLocalMode TLM,
                             GlobalVariable::UnnamedAddr UnnamedAddr) {
    if (!isValidVisibilityForLinkage(Visibility, Linkage))
      return error(NameLoc,
                   "symbol with local linkage must have default visibility");
  
    unsigned AddrSpace;
    bool IsConstant, IsExternallyInitialized;
    LocTy IsExternallyInitializedLoc;
    LocTy TyLoc;
  
    Type *Ty = nullptr;
    if (parseOptionalAddrSpace(AddrSpace) ||
        parseOptionalToken(lltok::kw_externally_initialized,
                           IsExternallyInitialized,
                           &IsExternallyInitializedLoc) ||
        parseGlobalType(IsConstant) || parseType(Ty, TyLoc))
      return true;
  
    // If the linkage is specified and is external, then no initializer is
    // present.
    Constant *Init = nullptr;
    if (!HasLinkage ||
        !GlobalValue::isValidDeclarationLinkage(
            (GlobalValue::LinkageTypes)Linkage)) {
      if (parseGlobalValue(Ty, Init))
        return true;
    }
  
    if (Ty->isFunctionTy() || !PointerType::isValidElementType(Ty))
      return error(TyLoc, "invalid type for global variable");
  
    GlobalValue *GVal = nullptr;
  
    // See if the global was forward referenced, if so, use the global.
    if (!Name.empty()) {
      auto I = ForwardRefVals.find(Name);
      if (I != ForwardRefVals.end()) {
        GVal = I->second.first;
        ForwardRefVals.erase(I);
      } else if (M->getNamedValue(Name)) {
        return error(NameLoc, "redefinition of global '@" + Name + "'");
      }
    } else {
      auto I = ForwardRefValIDs.find(NumberedVals.size());
      if (I != ForwardRefValIDs.end()) {
        GVal = I->second.first;
        ForwardRefValIDs.erase(I);
      }
    }
  
    GlobalVariable *GV = new GlobalVariable(
        *M, Ty, false, GlobalValue::ExternalLinkage, nullptr, Name, nullptr,
        GlobalVariable::NotThreadLocal, AddrSpace);
  
    if (Name.empty())
      NumberedVals.push_back(GV);
  
    // Set the parsed properties on the global.
    if (Init)
      GV->setInitializer(Init);
    GV->setConstant(IsConstant);
    GV->setLinkage((GlobalValue::LinkageTypes)Linkage);
    maybeSetDSOLocal(DSOLocal, *GV);
    GV->setVisibility((GlobalValue::VisibilityTypes)Visibility);
    GV->setDLLStorageClass((GlobalValue::DLLStorageClassTypes)DLLStorageClass);
    GV->setExternallyInitialized(IsExternallyInitialized);
    GV->setThreadLocalMode(TLM);
    GV->setUnnamedAddr(UnnamedAddr);
  
    if (GVal) {
      if (!GVal->getType()->isOpaque() && GVal->getValueType() != Ty)
        return error(
            TyLoc,
            "forward reference and definition of global have different types");
  
      GVal->replaceAllUsesWith(GV);
      GVal->eraseFromParent();
    }
  
    // parse attributes on the global.
    while (Lex.getKind() == lltok::comma) {
      Lex.Lex();
  
      if (Lex.getKind() == lltok::kw_section) {
        Lex.Lex();
        GV->setSection(Lex.getStrVal());
        if (parseToken(lltok::StringConstant, "expected global section string"))
          return true;
      } else if (Lex.getKind() == lltok::kw_partition) {
        Lex.Lex();
        GV->setPartition(Lex.getStrVal());
        if (parseToken(lltok::StringConstant, "expected partition string"))
          return true;
      } else if (Lex.getKind() == lltok::kw_align) {
        MaybeAlign Alignment;
        if (parseOptionalAlignment(Alignment))
          return true;
        GV->setAlignment(Alignment);
      } else if (Lex.getKind() == lltok::MetadataVar) {
        if (parseGlobalObjectMetadataAttachment(*GV))
          return true;
      } else {
        Comdat *C;
        if (parseOptionalComdat(Name, C))
          return true;
        if (C)
          GV->setComdat(C);
        else
          return tokError("unknown global variable property!");
      }
    }
  
    AttrBuilder Attrs;
    LocTy BuiltinLoc;
    std::vector<unsigned> FwdRefAttrGrps;
    if (parseFnAttributeValuePairs(Attrs, FwdRefAttrGrps, false, BuiltinLoc))
      return true;
    if (Attrs.hasAttributes() || !FwdRefAttrGrps.empty()) {
      GV->setAttributes(AttributeSet::get(Context, Attrs));
      ForwardRefAttrGroups[GV] = FwdRefAttrGrps;
    }
  
    return false;
  }
  
  /// parseUnnamedAttrGrp
  ///   ::= 'attributes' AttrGrpID '=' '{' AttrValPair+ '}'
  bool LLParser::parseUnnamedAttrGrp() {
    assert(Lex.getKind() == lltok::kw_attributes);
    LocTy AttrGrpLoc = Lex.getLoc();
    Lex.Lex();
  
    if (Lex.getKind() != lltok::AttrGrpID)
      return tokError("expected attribute group id");
  
    unsigned VarID = Lex.getUIntVal();
    std::vector<unsigned> unused;
    LocTy BuiltinLoc;
    Lex.Lex();
  
    if (parseToken(lltok::equal, "expected '=' here") ||
        parseToken(lltok::lbrace, "expected '{' here") ||
        parseFnAttributeValuePairs(NumberedAttrBuilders[VarID], unused, true,
                                   BuiltinLoc) ||
        parseToken(lltok::rbrace, "expected end of attribute group"))
      return true;
  
    if (!NumberedAttrBuilders[VarID].hasAttributes())
      return error(AttrGrpLoc, "attribute group has no attributes");
  
    return false;
  }
  
  static Attribute::AttrKind tokenToAttribute(lltok::Kind Kind) {
    switch (Kind) {
  #define GET_ATTR_NAMES
  #define ATTRIBUTE_ENUM(ENUM_NAME, DISPLAY_NAME) \
    case lltok::kw_##DISPLAY_NAME: \
      return Attribute::ENUM_NAME;
  #include "llvm/IR/Attributes.inc"
    default:
      return Attribute::None;
    }
  }
  
  bool LLParser::parseEnumAttribute(Attribute::AttrKind Attr, AttrBuilder &B,
                                    bool InAttrGroup) {
    if (Attribute::isTypeAttrKind(Attr))
      return parseRequiredTypeAttr(B, Lex.getKind(), Attr);
  
    switch (Attr) {
    case Attribute::Alignment: {
      MaybeAlign Alignment;
      if (InAttrGroup) {
        uint32_t Value = 0;
        Lex.Lex();
        if (parseToken(lltok::equal, "expected '=' here") || parseUInt32(Value))
          return true;
        Alignment = Align(Value);
      } else {
        if (parseOptionalAlignment(Alignment, true))
          return true;
      }
      B.addAlignmentAttr(Alignment);
      return false;
    }
    case Attribute::StackAlignment: {
      unsigned Alignment;
      if (InAttrGroup) {
        Lex.Lex();
        if (parseToken(lltok::equal, "expected '=' here") ||
            parseUInt32(Alignment))
          return true;
      } else {
        if (parseOptionalStackAlignment(Alignment))
          return true;
      }
      B.addStackAlignmentAttr(Alignment);
      return false;
    }
    case Attribute::AllocSize: {
      unsigned ElemSizeArg;
      Optional<unsigned> NumElemsArg;
      if (parseAllocSizeArguments(ElemSizeArg, NumElemsArg))
        return true;
      B.addAllocSizeAttr(ElemSizeArg, NumElemsArg);
      return false;
    }
    case Attribute::VScaleRange: {
      unsigned MinValue, MaxValue;
      if (parseVScaleRangeArguments(MinValue, MaxValue))
        return true;
      B.addVScaleRangeAttr(MinValue, MaxValue);
      return false;
    }
    case Attribute::Dereferenceable: {
      uint64_t Bytes;
      if (parseOptionalDerefAttrBytes(lltok::kw_dereferenceable, Bytes))
        return true;
      B.addDereferenceableAttr(Bytes);
      return false;
    }
    case Attribute::DereferenceableOrNull: {
      uint64_t Bytes;
      if (parseOptionalDerefAttrBytes(lltok::kw_dereferenceable_or_null, Bytes))
        return true;
      B.addDereferenceableOrNullAttr(Bytes);
      return false;
    }
    default:
      B.addAttribute(Attr);
      Lex.Lex();
      return false;
    }
  }
  
  /// parseFnAttributeValuePairs
  ///   ::= <attr> | <attr> '=' <value>
  bool LLParser::parseFnAttributeValuePairs(AttrBuilder &B,
                                            std::vector<unsigned> &FwdRefAttrGrps,
                                            bool InAttrGrp, LocTy &BuiltinLoc) {
    bool HaveError = false;
  
    B.clear();
  
    while (true) {
      lltok::Kind Token = Lex.getKind();
      if (Token == lltok::rbrace)
        return HaveError; // Finished.
  
      if (Token == lltok::StringConstant) {
        if (parseStringAttribute(B))
          return true;
        continue;
      }
  
      if (Token == lltok::AttrGrpID) {
        // Allow a function to reference an attribute group:
        //
        //   define void @foo() #1 { ... }
        if (InAttrGrp) {
          HaveError |= error(
              Lex.getLoc(),
              "cannot have an attribute group reference in an attribute group");
        } else {
          // Save the reference to the attribute group. We'll fill it in later.
          FwdRefAttrGrps.push_back(Lex.getUIntVal());
        }
        Lex.Lex();
        continue;
      }
  
      SMLoc Loc = Lex.getLoc();
      if (Token == lltok::kw_builtin)
        BuiltinLoc = Loc;
  
      Attribute::AttrKind Attr = tokenToAttribute(Token);
      if (Attr == Attribute::None) {
        if (!InAttrGrp)
          return HaveError;
        return error(Lex.getLoc(), "unterminated attribute group");
      }
  
      if (parseEnumAttribute(Attr, B, InAttrGrp))
        return true;
  
      // As a hack, we allow function alignment to be initially parsed as an
      // attribute on a function declaration/definition or added to an attribute
      // group and later moved to the alignment field.
      if (!Attribute::canUseAsFnAttr(Attr) && Attr != Attribute::Alignment)
        HaveError |= error(Loc, "this attribute does not apply to functions");
    }
  }
  
  //===----------------------------------------------------------------------===//
  // GlobalValue Reference/Resolution Routines.
  //===----------------------------------------------------------------------===//
  
  static inline GlobalValue *createGlobalFwdRef(Module *M, PointerType *PTy) {
    // For opaque pointers, the used global type does not matter. We will later
    // RAUW it with a global/function of the correct type.
    if (PTy->isOpaque())
      return new GlobalVariable(*M, Type::getInt8Ty(M->getContext()), false,
                                GlobalValue::ExternalWeakLinkage, nullptr, "",
                                nullptr, GlobalVariable::NotThreadLocal,
                                PTy->getAddressSpace());
  
    if (auto *FT = dyn_cast<FunctionType>(PTy->getPointerElementType()))
      return Function::Create(FT, GlobalValue::ExternalWeakLinkage,
                              PTy->getAddressSpace(), "", M);
    else
      return new GlobalVariable(*M, PTy->getPointerElementType(), false,
                                GlobalValue::ExternalWeakLinkage, nullptr, "",
                                nullptr, GlobalVariable::NotThreadLocal,
                                PTy->getAddressSpace());
  }
  
  Value *LLParser::checkValidVariableType(LocTy Loc, const Twine &Name, Type *Ty,
                                          Value *Val) {
    Type *ValTy = Val->getType();
    if (ValTy == Ty)
      return Val;
    if (Ty->isLabelTy())
      error(Loc, "'" + Name + "' is not a basic block");
    else
      error(Loc, "'" + Name + "' defined with type '" +
                     getTypeString(Val->getType()) + "' but expected '" +
                     getTypeString(Ty) + "'");
    return nullptr;
  }
  
  /// getGlobalVal - Get a value with the specified name or ID, creating a
  /// forward reference record if needed.  This can return null if the value
  /// exists but does not have the right type.
  GlobalValue *LLParser::getGlobalVal(const std::string &Name, Type *Ty,
                                      LocTy Loc) {
    PointerType *PTy = dyn_cast<PointerType>(Ty);
    if (!PTy) {
      error(Loc, "global variable reference must have pointer type");
      return nullptr;
    }
  
    // Look this name up in the normal function symbol table.
    GlobalValue *Val =
      cast_or_null<GlobalValue>(M->getValueSymbolTable().lookup(Name));
  
    // If this is a forward reference for the value, see if we already created a
    // forward ref record.
    if (!Val) {
      auto I = ForwardRefVals.find(Name);
      if (I != ForwardRefVals.end())
        Val = I->second.first;
    }
  
    // If we have the value in the symbol table or fwd-ref table, return it.
    if (Val)
      return cast_or_null<GlobalValue>(
          checkValidVariableType(Loc, "@" + Name, Ty, Val));
  
    // Otherwise, create a new forward reference for this value and remember it.
    GlobalValue *FwdVal = createGlobalFwdRef(M, PTy);
    ForwardRefVals[Name] = std::make_pair(FwdVal, Loc);
    return FwdVal;
  }
  
  GlobalValue *LLParser::getGlobalVal(unsigned ID, Type *Ty, LocTy Loc) {
    PointerType *PTy = dyn_cast<PointerType>(Ty);
    if (!PTy) {
      error(Loc, "global variable reference must have pointer type");
      return nullptr;
    }
  
    GlobalValue *Val = ID < NumberedVals.size() ? NumberedVals[ID] : nullptr;
  
    // If this is a forward reference for the value, see if we already created a
    // forward ref record.
    if (!Val) {
      auto I = ForwardRefValIDs.find(ID);
      if (I != ForwardRefValIDs.end())
        Val = I->second.first;
    }
  
    // If we have the value in the symbol table or fwd-ref table, return it.
    if (Val)
      return cast_or_null<GlobalValue>(
          checkValidVariableType(Loc, "@" + Twine(ID), Ty, Val));
  
    // Otherwise, create a new forward reference for this value and remember it.
    GlobalValue *FwdVal = createGlobalFwdRef(M, PTy);
    ForwardRefValIDs[ID] = std::make_pair(FwdVal, Loc);
    return FwdVal;
  }
  
  //===----------------------------------------------------------------------===//
  // Comdat Reference/Resolution Routines.
  //===----------------------------------------------------------------------===//
  
  Comdat *LLParser::getComdat(const std::string &Name, LocTy Loc) {
    // Look this name up in the comdat symbol table.
    Module::ComdatSymTabType &ComdatSymTab = M->getComdatSymbolTable();
    Module::ComdatSymTabType::iterator I = ComdatSymTab.find(Name);
    if (I != ComdatSymTab.end())
      return &I->second;
  
    // Otherwise, create a new forward reference for this value and remember it.
    Comdat *C = M->getOrInsertComdat(Name);
    ForwardRefComdats[Name] = Loc;
    return C;
  }
  
  //===----------------------------------------------------------------------===//
  // Helper Routines.
  //===----------------------------------------------------------------------===//
  
  /// parseToken - If the current token has the specified kind, eat it and return
  /// success.  Otherwise, emit the specified error and return failure.
  bool LLParser::parseToken(lltok::Kind T, const char *ErrMsg) {
    if (Lex.getKind() != T)
      return tokError(ErrMsg);
    Lex.Lex();
    return false;
  }
  
  /// parseStringConstant
  ///   ::= StringConstant
  bool LLParser::parseStringConstant(std::string &Result) {
    if (Lex.getKind() != lltok::StringConstant)
      return tokError("expected string constant");
    Result = Lex.getStrVal();
    Lex.Lex();
    return false;
  }
  
  /// parseUInt32
  ///   ::= uint32
  bool LLParser::parseUInt32(uint32_t &Val) {
    if (Lex.getKind() != lltok::APSInt || Lex.getAPSIntVal().isSigned())
      return tokError("expected integer");
    uint64_t Val64 = Lex.getAPSIntVal().getLimitedValue(0xFFFFFFFFULL+1);
    if (Val64 != unsigned(Val64))
      return tokError("expected 32-bit integer (too large)");
    Val = Val64;
    Lex.Lex();
    return false;
  }
  
  /// parseUInt64
  ///   ::= uint64
  bool LLParser::parseUInt64(uint64_t &Val) {
    if (Lex.getKind() != lltok::APSInt || Lex.getAPSIntVal().isSigned())
      return tokError("expected integer");
    Val = Lex.getAPSIntVal().getLimitedValue();
    Lex.Lex();
    return false;
  }
  
  /// parseTLSModel
  ///   := 'localdynamic'
  ///   := 'initialexec'
  ///   := 'localexec'
  bool LLParser::parseTLSModel(GlobalVariable::ThreadLocalMode &TLM) {
    switch (Lex.getKind()) {
      default:
        return tokError("expected localdynamic, initialexec or localexec");
      case lltok::kw_localdynamic:
        TLM = GlobalVariable::LocalDynamicTLSModel;
        break;
      case lltok::kw_initialexec:
        TLM = GlobalVariable::InitialExecTLSModel;
        break;
      case lltok::kw_localexec:
        TLM = GlobalVariable::LocalExecTLSModel;
        break;
    }
  
    Lex.Lex();
    return false;
  }
  
  /// parseOptionalThreadLocal
  ///   := /*empty*/
  ///   := 'thread_local'
  ///   := 'thread_local' '(' tlsmodel ')'
  bool LLParser::parseOptionalThreadLocal(GlobalVariable::ThreadLocalMode &TLM) {
    TLM = GlobalVariable::NotThreadLocal;
    if (!EatIfPresent(lltok::kw_thread_local))
      return false;
  
    TLM = GlobalVariable::GeneralDynamicTLSModel;
    if (Lex.getKind() == lltok::lparen) {
      Lex.Lex();
      return parseTLSModel(TLM) ||
             parseToken(lltok::rparen, "expected ')' after thread local model");
    }
    return false;
  }
  
  /// parseOptionalAddrSpace
  ///   := /*empty*/
  ///   := 'addrspace' '(' uint32 ')'
  bool LLParser::parseOptionalAddrSpace(unsigned &AddrSpace, unsigned DefaultAS) {
    AddrSpace = DefaultAS;
    if (!EatIfPresent(lltok::kw_addrspace))
      return false;
    return parseToken(lltok::lparen, "expected '(' in address space") ||
           parseUInt32(AddrSpace) ||
           parseToken(lltok::rparen, "expected ')' in address space");
  }
  
  /// parseStringAttribute
  ///   := StringConstant
  ///   := StringConstant '=' StringConstant
  bool LLParser::parseStringAttribute(AttrBuilder &B) {
    std::string Attr = Lex.getStrVal();
    Lex.Lex();
    std::string Val;
    if (EatIfPresent(lltok::equal) && parseStringConstant(Val))
      return true;
    B.addAttribute(Attr, Val);
    return false;
  }
  
  /// Parse a potentially empty list of parameter or return attributes.
  bool LLParser::parseOptionalParamOrReturnAttrs(AttrBuilder &B, bool IsParam) {
    bool HaveError = false;
  
    B.clear();
  
    while (true) {
      lltok::Kind Token = Lex.getKind();
      if (Token == lltok::StringConstant) {
        if (parseStringAttribute(B))
          return true;
        continue;
      }
  
      SMLoc Loc = Lex.getLoc();
      Attribute::AttrKind Attr = tokenToAttribute(Token);
      if (Attr == Attribute::None)
        return HaveError;
  
      if (parseEnumAttribute(Attr, B, /* InAttrGroup */ false))
        return true;
  
      if (IsParam && !Attribute::canUseAsParamAttr(Attr))
        HaveError |= error(Loc, "this attribute does not apply to parameters");
      if (!IsParam && !Attribute::canUseAsRetAttr(Attr))
        HaveError |= error(Loc, "this attribute does not apply to return values");
    }
  }
  
  static unsigned parseOptionalLinkageAux(lltok::Kind Kind, bool &HasLinkage) {
    HasLinkage = true;
    switch (Kind) {
    default:
      HasLinkage = false;
      return GlobalValue::ExternalLinkage;
    case lltok::kw_private:
      return GlobalValue::PrivateLinkage;
    case lltok::kw_internal:
      return GlobalValue::InternalLinkage;
    case lltok::kw_weak:
      return GlobalValue::WeakAnyLinkage;
    case lltok::kw_weak_odr:
      return GlobalValue::WeakODRLinkage;
    case lltok::kw_linkonce:
      return GlobalValue::LinkOnceAnyLinkage;
    case lltok::kw_linkonce_odr:
      return GlobalValue::LinkOnceODRLinkage;
    case lltok::kw_available_externally:
      return GlobalValue::AvailableExternallyLinkage;
    case lltok::kw_appending:
      return GlobalValue::AppendingLinkage;
    case lltok::kw_common:
      return GlobalValue::CommonLinkage;
    case lltok::kw_extern_weak:
      return GlobalValue::ExternalWeakLinkage;
    case lltok::kw_external:
      return GlobalValue::ExternalLinkage;
    }
  }
  
  /// parseOptionalLinkage
  ///   ::= /*empty*/
  ///   ::= 'private'
  ///   ::= 'internal'
  ///   ::= 'weak'
  ///   ::= 'weak_odr'
  ///   ::= 'linkonce'
  ///   ::= 'linkonce_odr'
  ///   ::= 'available_externally'
  ///   ::= 'appending'
  ///   ::= 'common'
  ///   ::= 'extern_weak'
  ///   ::= 'external'
  bool LLParser::parseOptionalLinkage(unsigned &Res, bool &HasLinkage,
                                      unsigned &Visibility,
                                      unsigned &DLLStorageClass, bool &DSOLocal) {
    Res = parseOptionalLinkageAux(Lex.getKind(), HasLinkage);
    if (HasLinkage)
      Lex.Lex();
    parseOptionalDSOLocal(DSOLocal);
    parseOptionalVisibility(Visibility);
    parseOptionalDLLStorageClass(DLLStorageClass);
  
    if (DSOLocal && DLLStorageClass == GlobalValue::DLLImportStorageClass) {
      return error(Lex.getLoc(), "dso_location and DLL-StorageClass mismatch");
    }
  
    return false;
  }
  
  void LLParser::parseOptionalDSOLocal(bool &DSOLocal) {
    switch (Lex.getKind()) {
    default:
      DSOLocal = false;
      break;
    case lltok::kw_dso_local:
      DSOLocal = true;
      Lex.Lex();
      break;
    case lltok::kw_dso_preemptable:
      DSOLocal = false;
      Lex.Lex();
      break;
    }
  }
  
  /// parseOptionalVisibility
  ///   ::= /*empty*/
  ///   ::= 'default'
  ///   ::= 'hidden'
  ///   ::= 'protected'
  ///
  void LLParser::parseOptionalVisibility(unsigned &Res) {
    switch (Lex.getKind()) {
    default:
      Res = GlobalValue::DefaultVisibility;
      return;
    case lltok::kw_default:
      Res = GlobalValue::DefaultVisibility;
      break;
    case lltok::kw_hidden:
      Res = GlobalValue::HiddenVisibility;
      break;
    case lltok::kw_protected:
      Res = GlobalValue::ProtectedVisibility;
      break;
    }
    Lex.Lex();
  }
  
  /// parseOptionalDLLStorageClass
  ///   ::= /*empty*/
  ///   ::= 'dllimport'
  ///   ::= 'dllexport'
  ///
  void LLParser::parseOptionalDLLStorageClass(unsigned &Res) {
    switch (Lex.getKind()) {
    default:
      Res = GlobalValue::DefaultStorageClass;
      return;
    case lltok::kw_dllimport:
      Res = GlobalValue::DLLImportStorageClass;
      break;
    case lltok::kw_dllexport:
      Res = GlobalValue::DLLExportStorageClass;
      break;
    }
    Lex.Lex();
  }
  
  /// parseOptionalCallingConv
  ///   ::= /*empty*/
  ///   ::= 'ccc'
  ///   ::= 'fastcc'
  ///   ::= 'intel_ocl_bicc'
  ///   ::= 'coldcc'
  ///   ::= 'cfguard_checkcc'
  ///   ::= 'x86_stdcallcc'
  ///   ::= 'x86_fastcallcc'
  ///   ::= 'x86_thiscallcc'
  ///   ::= 'x86_vectorcallcc'
  ///   ::= 'arm_apcscc'
  ///   ::= 'arm_aapcscc'
  ///   ::= 'arm_aapcs_vfpcc'
  ///   ::= 'aarch64_vector_pcs'
  ///   ::= 'aarch64_sve_vector_pcs'
  ///   ::= 'msp430_intrcc'
  ///   ::= 'avr_intrcc'
  ///   ::= 'avr_signalcc'
  ///   ::= 'ptx_kernel'
  ///   ::= 'ptx_device'
  ///   ::= 'spir_func'
  ///   ::= 'spir_kernel'
  ///   ::= 'x86_64_sysvcc'
  ///   ::= 'win64cc'
  ///   ::= 'webkit_jscc'
  ///   ::= 'anyregcc'
  ///   ::= 'preserve_mostcc'
  ///   ::= 'preserve_allcc'
  ///   ::= 'ghccc'
  ///   ::= 'swiftcc'
  ///   ::= 'swifttailcc'
  ///   ::= 'x86_intrcc'
  ///   ::= 'hhvmcc'
  ///   ::= 'hhvm_ccc'
  ///   ::= 'cxx_fast_tlscc'
  ///   ::= 'amdgpu_vs'
  ///   ::= 'amdgpu_ls'
  ///   ::= 'amdgpu_hs'
  ///   ::= 'amdgpu_es'
  ///   ::= 'amdgpu_gs'
  ///   ::= 'amdgpu_ps'
  ///   ::= 'amdgpu_cs'
  ///   ::= 'amdgpu_kernel'
  ///   ::= 'tailcc'
  ///   ::= 'cc' UINT
  ///
  bool LLParser::parseOptionalCallingConv(unsigned &CC) {
    switch (Lex.getKind()) {
    default:                       CC = CallingConv::C; return false;
    case lltok::kw_ccc:            CC = CallingConv::C; break;
    case lltok::kw_fastcc:         CC = CallingConv::Fast; break;
    case lltok::kw_coldcc:         CC = CallingConv::Cold; break;
    case lltok::kw_cfguard_checkcc: CC = CallingConv::CFGuard_Check; break;
    case lltok::kw_x86_stdcallcc:  CC = CallingConv::X86_StdCall; break;
    case lltok::kw_x86_fastcallcc: CC = CallingConv::X86_FastCall; break;
    case lltok::kw_x86_regcallcc:  CC = CallingConv::X86_RegCall; break;
    case lltok::kw_x86_thiscallcc: CC = CallingConv::X86_ThisCall; break;
    case lltok::kw_x86_vectorcallcc:CC = CallingConv::X86_VectorCall; break;
    case lltok::kw_arm_apcscc:     CC = CallingConv::ARM_APCS; break;
    case lltok::kw_arm_aapcscc:    CC = CallingConv::ARM_AAPCS; break;
    case lltok::kw_arm_aapcs_vfpcc:CC = CallingConv::ARM_AAPCS_VFP; break;
    case lltok::kw_aarch64_vector_pcs:CC = CallingConv::AArch64_VectorCall; break;
    case lltok::kw_aarch64_sve_vector_pcs:
      CC = CallingConv::AArch64_SVE_VectorCall;
      break;
    case lltok::kw_msp430_intrcc:  CC = CallingConv::MSP430_INTR; break;
    case lltok::kw_avr_intrcc:     CC = CallingConv::AVR_INTR; break;
    case lltok::kw_avr_signalcc:   CC = CallingConv::AVR_SIGNAL; break;
    case lltok::kw_ptx_kernel:     CC = CallingConv::PTX_Kernel; break;
    case lltok::kw_ptx_device:     CC = CallingConv::PTX_Device; break;
    case lltok::kw_spir_kernel:    CC = CallingConv::SPIR_KERNEL; break;
    case lltok::kw_spir_func:      CC = CallingConv::SPIR_FUNC; break;
    case lltok::kw_intel_ocl_bicc: CC = CallingConv::Intel_OCL_BI; break;
    case lltok::kw_x86_64_sysvcc:  CC = CallingConv::X86_64_SysV; break;
    case lltok::kw_win64cc:        CC = CallingConv::Win64; break;
    case lltok::kw_webkit_jscc:    CC = CallingConv::WebKit_JS; break;
    case lltok::kw_anyregcc:       CC = CallingConv::AnyReg; break;
    case lltok::kw_preserve_mostcc:CC = CallingConv::PreserveMost; break;
    case lltok::kw_preserve_allcc: CC = CallingConv::PreserveAll; break;
    case lltok::kw_ghccc:          CC = CallingConv::GHC; break;
    case lltok::kw_swiftcc:        CC = CallingConv::Swift; break;
    case lltok::kw_swifttailcc:    CC = CallingConv::SwiftTail; break;
    case lltok::kw_x86_intrcc:     CC = CallingConv::X86_INTR; break;
    case lltok::kw_hhvmcc:         CC = CallingConv::HHVM; break;
    case lltok::kw_hhvm_ccc:       CC = CallingConv::HHVM_C; break;
    case lltok::kw_cxx_fast_tlscc: CC = CallingConv::CXX_FAST_TLS; break;
    case lltok::kw_amdgpu_vs:      CC = CallingConv::AMDGPU_VS; break;
    case lltok::kw_amdgpu_gfx:     CC = CallingConv::AMDGPU_Gfx; break;
    case lltok::kw_amdgpu_ls:      CC = CallingConv::AMDGPU_LS; break;
    case lltok::kw_amdgpu_hs:      CC = CallingConv::AMDGPU_HS; break;
    case lltok::kw_amdgpu_es:      CC = CallingConv::AMDGPU_ES; break;
    case lltok::kw_amdgpu_gs:      CC = CallingConv::AMDGPU_GS; break;
    case lltok::kw_amdgpu_ps:      CC = CallingConv::AMDGPU_PS; break;
    case lltok::kw_amdgpu_cs:      CC = CallingConv::AMDGPU_CS; break;
    case lltok::kw_amdgpu_kernel:  CC = CallingConv::AMDGPU_KERNEL; break;
    case lltok::kw_tailcc:         CC = CallingConv::Tail; break;
    case lltok::kw_cc: {
        Lex.Lex();
        return parseUInt32(CC);
      }
    }
  
    Lex.Lex();
    return false;
  }
  
  /// parseMetadataAttachment
  ///   ::= !dbg !42
  bool LLParser::parseMetadataAttachment(unsigned &Kind, MDNode *&MD) {
    assert(Lex.getKind() == lltok::MetadataVar && "Expected metadata attachment");
  
    std::string Name = Lex.getStrVal();
    Kind = M->getMDKindID(Name);
    Lex.Lex();
  
    return parseMDNode(MD);
  }
  
  /// parseInstructionMetadata
  ///   ::= !dbg !42 (',' !dbg !57)*
  bool LLParser::parseInstructionMetadata(Instruction &Inst) {
    do {
      if (Lex.getKind() != lltok::MetadataVar)
        return tokError("expected metadata after comma");
  
      unsigned MDK;
      MDNode *N;
      if (parseMetadataAttachment(MDK, N))
        return true;
  
      Inst.setMetadata(MDK, N);
      if (MDK == LLVMContext::MD_tbaa)
        InstsWithTBAATag.push_back(&Inst);
  
      // If this is the end of the list, we're done.
    } while (EatIfPresent(lltok::comma));
    return false;
  }
  
  /// parseGlobalObjectMetadataAttachment
  ///   ::= !dbg !57
  bool LLParser::parseGlobalObjectMetadataAttachment(GlobalObject &GO) {
    unsigned MDK;
    MDNode *N;
    if (parseMetadataAttachment(MDK, N))
      return true;
  
    GO.addMetadata(MDK, *N);
    return false;
  }
  
  /// parseOptionalFunctionMetadata
  ///   ::= (!dbg !57)*
  bool LLParser::parseOptionalFunctionMetadata(Function &F) {
    while (Lex.getKind() == lltok::MetadataVar)
      if (parseGlobalObjectMetadataAttachment(F))
        return true;
    return false;
  }
  
  /// parseOptionalAlignment
  ///   ::= /* empty */
  ///   ::= 'align' 4
  bool LLParser::parseOptionalAlignment(MaybeAlign &Alignment, bool AllowParens) {
    Alignment = None;
    if (!EatIfPresent(lltok::kw_align))
      return false;
    LocTy AlignLoc = Lex.getLoc();
    uint64_t Value = 0;
  
    LocTy ParenLoc = Lex.getLoc();
    bool HaveParens = false;
    if (AllowParens) {
      if (EatIfPresent(lltok::lparen))
        HaveParens = true;
    }
  
    if (parseUInt64(Value))
      return true;
  
    if (HaveParens && !EatIfPresent(lltok::rparen))
      return error(ParenLoc, "expected ')'");
  
    if (!isPowerOf2_64(Value))
      return error(AlignLoc, "alignment is not a power of two");
    if (Value > Value::MaximumAlignment)
      return error(AlignLoc, "huge alignments are not supported yet");
    Alignment = Align(Value);
    return false;
  }
  
  /// parseOptionalDerefAttrBytes
  ///   ::= /* empty */
  ///   ::= AttrKind '(' 4 ')'
  ///
  /// where AttrKind is either 'dereferenceable' or 'dereferenceable_or_null'.
  bool LLParser::parseOptionalDerefAttrBytes(lltok::Kind AttrKind,
                                             uint64_t &Bytes) {
    assert((AttrKind == lltok::kw_dereferenceable ||
            AttrKind == lltok::kw_dereferenceable_or_null) &&
           "contract!");
  
    Bytes = 0;
    if (!EatIfPresent(AttrKind))
      return false;
    LocTy ParenLoc = Lex.getLoc();
    if (!EatIfPresent(lltok::lparen))
      return error(ParenLoc, "expected '('");
    LocTy DerefLoc = Lex.getLoc();
    if (parseUInt64(Bytes))
      return true;
    ParenLoc = Lex.getLoc();
    if (!EatIfPresent(lltok::rparen))
      return error(ParenLoc, "expected ')'");
    if (!Bytes)
      return error(DerefLoc, "dereferenceable bytes must be non-zero");
    return false;
  }
  
  /// parseOptionalCommaAlign
  ///   ::=
  ///   ::= ',' align 4
  ///
  /// This returns with AteExtraComma set to true if it ate an excess comma at the
  /// end.
  bool LLParser::parseOptionalCommaAlign(MaybeAlign &Alignment,
                                         bool &AteExtraComma) {
    AteExtraComma = false;
    while (EatIfPresent(lltok::comma)) {
      // Metadata at the end is an early exit.
      if (Lex.getKind() == lltok::MetadataVar) {
        AteExtraComma = true;
        return false;
      }
  
      if (Lex.getKind() != lltok::kw_align)
        return error(Lex.getLoc(), "expected metadata or 'align'");
  
      if (parseOptionalAlignment(Alignment))
        return true;
    }
  
    return false;
  }
  
  /// parseOptionalCommaAddrSpace
  ///   ::=
  ///   ::= ',' addrspace(1)
  ///
  /// This returns with AteExtraComma set to true if it ate an excess comma at the
  /// end.
  bool LLParser::parseOptionalCommaAddrSpace(unsigned &AddrSpace, LocTy &Loc,
                                             bool &AteExtraComma) {
    AteExtraComma = false;
    while (EatIfPresent(lltok::comma)) {
      // Metadata at the end is an early exit.
      if (Lex.getKind() == lltok::MetadataVar) {
        AteExtraComma = true;
        return false;
      }
  
      Loc = Lex.getLoc();
      if (Lex.getKind() != lltok::kw_addrspace)
        return error(Lex.getLoc(), "expected metadata or 'addrspace'");
  
      if (parseOptionalAddrSpace(AddrSpace))
        return true;
    }
  
    return false;
  }
  
  bool LLParser::parseAllocSizeArguments(unsigned &BaseSizeArg,
                                         Optional<unsigned> &HowManyArg) {
    Lex.Lex();
  
    auto StartParen = Lex.getLoc();
    if (!EatIfPresent(lltok::lparen))
      return error(StartParen, "expected '('");
  
    if (parseUInt32(BaseSizeArg))
      return true;
  
    if (EatIfPresent(lltok::comma)) {
      auto HowManyAt = Lex.getLoc();
      unsigned HowMany;
      if (parseUInt32(HowMany))
        return true;
      if (HowMany == BaseSizeArg)
        return error(HowManyAt,
                     "'allocsize' indices can't refer to the same parameter");
      HowManyArg = HowMany;
    } else
      HowManyArg = None;
  
    auto EndParen = Lex.getLoc();
    if (!EatIfPresent(lltok::rparen))
      return error(EndParen, "expected ')'");
    return false;
  }
  
  bool LLParser::parseVScaleRangeArguments(unsigned &MinValue,
                                           unsigned &MaxValue) {
    Lex.Lex();
  
    auto StartParen = Lex.getLoc();
    if (!EatIfPresent(lltok::lparen))
      return error(StartParen, "expected '('");
  
    if (parseUInt32(MinValue))
      return true;
  
    if (EatIfPresent(lltok::comma)) {
      if (parseUInt32(MaxValue))
        return true;
    } else
      MaxValue = MinValue;
  
    auto EndParen = Lex.getLoc();
    if (!EatIfPresent(lltok::rparen))
      return error(EndParen, "expected ')'");
    return false;
  }
  
  /// parseScopeAndOrdering
  ///   if isAtomic: ::= SyncScope? AtomicOrdering
  ///   else: ::=
  ///
  /// This sets Scope and Ordering to the parsed values.
  bool LLParser::parseScopeAndOrdering(bool IsAtomic, SyncScope::ID &SSID,
                                       AtomicOrdering &Ordering) {
    if (!IsAtomic)
      return false;
  
    return parseScope(SSID) || parseOrdering(Ordering);
  }
  
  /// parseScope
  ///   ::= syncscope("singlethread" | "<target scope>")?
  ///
  /// This sets synchronization scope ID to the ID of the parsed value.
  bool LLParser::parseScope(SyncScope::ID &SSID) {
    SSID = SyncScope::System;
    if (EatIfPresent(lltok::kw_syncscope)) {
      auto StartParenAt = Lex.getLoc();
      if (!EatIfPresent(lltok::lparen))
        return error(StartParenAt, "Expected '(' in syncscope");
  
      std::string SSN;
      auto SSNAt = Lex.getLoc();
      if (parseStringConstant(SSN))
        return error(SSNAt, "Expected synchronization scope name");
  
      auto EndParenAt = Lex.getLoc();
      if (!EatIfPresent(lltok::rparen))
        return error(EndParenAt, "Expected ')' in syncscope");
  
      SSID = Context.getOrInsertSyncScopeID(SSN);
    }
  
    return false;
  }
  
  /// parseOrdering
  ///   ::= AtomicOrdering
  ///
  /// This sets Ordering to the parsed value.
  bool LLParser::parseOrdering(AtomicOrdering &Ordering) {
    switch (Lex.getKind()) {
    default:
      return tokError("Expected ordering on atomic instruction");
    case lltok::kw_unordered: Ordering = AtomicOrdering::Unordered; break;
    case lltok::kw_monotonic: Ordering = AtomicOrdering::Monotonic; break;
    // Not specified yet:
    // case lltok::kw_consume: Ordering = AtomicOrdering::Consume; break;
    case lltok::kw_acquire: Ordering = AtomicOrdering::Acquire; break;
    case lltok::kw_release: Ordering = AtomicOrdering::Release; break;
    case lltok::kw_acq_rel: Ordering = AtomicOrdering::AcquireRelease; break;
    case lltok::kw_seq_cst:
      Ordering = AtomicOrdering::SequentiallyConsistent;
      break;
    }
    Lex.Lex();
    return false;
  }
  
  /// parseOptionalStackAlignment
  ///   ::= /* empty */
  ///   ::= 'alignstack' '(' 4 ')'
  bool LLParser::parseOptionalStackAlignment(unsigned &Alignment) {
    Alignment = 0;
    if (!EatIfPresent(lltok::kw_alignstack))
      return false;
    LocTy ParenLoc = Lex.getLoc();
    if (!EatIfPresent(lltok::lparen))
      return error(ParenLoc, "expected '('");
    LocTy AlignLoc = Lex.getLoc();
    if (parseUInt32(Alignment))
      return true;
    ParenLoc = Lex.getLoc();
    if (!EatIfPresent(lltok::rparen))
      return error(ParenLoc, "expected ')'");
    if (!isPowerOf2_32(Alignment))
      return error(AlignLoc, "stack alignment is not a power of two");
    return false;
  }
  
  /// parseIndexList - This parses the index list for an insert/extractvalue
  /// instruction.  This sets AteExtraComma in the case where we eat an extra
  /// comma at the end of the line and find that it is followed by metadata.
  /// Clients that don't allow metadata can call the version of this function that
  /// only takes one argument.
  ///
  /// parseIndexList
  ///    ::=  (',' uint32)+
  ///
  bool LLParser::parseIndexList(SmallVectorImpl<unsigned> &Indices,
                                bool &AteExtraComma) {
    AteExtraComma = false;
  
    if (Lex.getKind() != lltok::comma)
      return tokError("expected ',' as start of index list");
  
    while (EatIfPresent(lltok::comma)) {
      if (Lex.getKind() == lltok::MetadataVar) {
        if (Indices.empty())
          return tokError("expected index");
        AteExtraComma = true;
        return false;
      }
      unsigned Idx = 0;
      if (parseUInt32(Idx))
        return true;
      Indices.push_back(Idx);
    }
  
    return false;
  }
  
  //===----------------------------------------------------------------------===//
  // Type Parsing.
  //===----------------------------------------------------------------------===//
  
  /// parseType - parse a type.
  bool LLParser::parseType(Type *&Result, const Twine &Msg, bool AllowVoid) {
    SMLoc TypeLoc = Lex.getLoc();
    switch (Lex.getKind()) {
    default:
      return tokError(Msg);
    case lltok::Type:
      // Type ::= 'float' | 'void' (etc)
      Result = Lex.getTyVal();
      Lex.Lex();
  
      // Handle "ptr" opaque pointer type.
      //
      // Type ::= ptr ('addrspace' '(' uint32 ')')?
      if (Result->isOpaquePointerTy()) {
        unsigned AddrSpace;
        if (parseOptionalAddrSpace(AddrSpace))
          return true;
        Result = PointerType::get(getContext(), AddrSpace);
  
        // Give a nice error for 'ptr*'.
        if (Lex.getKind() == lltok::star)
          return tokError("ptr* is invalid - use ptr instead");
  
        // Fall through to parsing the type suffixes only if this 'ptr' is a
        // function return. Otherwise, return success, implicitly rejecting other
        // suffixes.
        if (Lex.getKind() != lltok::lparen)
          return false;
      }
      break;
    case lltok::lbrace:
      // Type ::= StructType
      if (parseAnonStructType(Result, false))
        return true;
      break;
    case lltok::lsquare:
      // Type ::= '[' ... ']'
      Lex.Lex(); // eat the lsquare.
      if (parseArrayVectorType(Result, false))
        return true;
      break;
    case lltok::less: // Either vector or packed struct.
      // Type ::= '<' ... '>'
      Lex.Lex();
      if (Lex.getKind() == lltok::lbrace) {
        if (parseAnonStructType(Result, true) ||
            parseToken(lltok::greater, "expected '>' at end of packed struct"))
          return true;
      } else if (parseArrayVectorType(Result, true))
        return true;
      break;
    case lltok::LocalVar: {
      // Type ::= %foo
      std::pair<Type*, LocTy> &Entry = NamedTypes[Lex.getStrVal()];
  
      // If the type hasn't been defined yet, create a forward definition and
      // remember where that forward def'n was seen (in case it never is defined).
      if (!Entry.first) {
        Entry.first = StructType::create(Context, Lex.getStrVal());
        Entry.second = Lex.getLoc();
      }
      Result = Entry.first;
      Lex.Lex();
      break;
    }
  
    case lltok::LocalVarID: {
      // Type ::= %4
      std::pair<Type*, LocTy> &Entry = NumberedTypes[Lex.getUIntVal()];
  
      // If the type hasn't been defined yet, create a forward definition and
      // remember where that forward def'n was seen (in case it never is defined).
      if (!Entry.first) {
        Entry.first = StructType::create(Context);
        Entry.second = Lex.getLoc();
      }
      Result = Entry.first;
      Lex.Lex();
      break;
    }
    }
  
    // parse the type suffixes.
    while (true) {
      switch (Lex.getKind()) {
      // End of type.
      default:
        if (!AllowVoid && Result->isVoidTy())
          return error(TypeLoc, "void type only allowed for function results");
        return false;
  
      // Type ::= Type '*'
      case lltok::star:
        if (Result->isLabelTy())
          return tokError("basic block pointers are invalid");
        if (Result->isVoidTy())
          return tokError("pointers to void are invalid - use i8* instead");
        if (!PointerType::isValidElementType(Result))
          return tokError("pointer to this type is invalid");
        Result = PointerType::getUnqual(Result);
        Lex.Lex();
        break;
  
      // Type ::= Type 'addrspace' '(' uint32 ')' '*'
      case lltok::kw_addrspace: {
        if (Result->isLabelTy())
          return tokError("basic block pointers are invalid");
        if (Result->isVoidTy())
          return tokError("pointers to void are invalid; use i8* instead");
        if (!PointerType::isValidElementType(Result))
          return tokError("pointer to this type is invalid");
        unsigned AddrSpace;
        if (parseOptionalAddrSpace(AddrSpace) ||
            parseToken(lltok::star, "expected '*' in address space"))
          return true;
  
        Result = PointerType::get(Result, AddrSpace);
        break;
      }
  
      /// Types '(' ArgTypeListI ')' OptFuncAttrs
      case lltok::lparen:
        if (parseFunctionType(Result))
          return true;
        break;
      }
    }
  }
  
  /// parseParameterList
  ///    ::= '(' ')'
  ///    ::= '(' Arg (',' Arg)* ')'
  ///  Arg
  ///    ::= Type OptionalAttributes Value OptionalAttributes
  bool LLParser::parseParameterList(SmallVectorImpl<ParamInfo> &ArgList,
                                    PerFunctionState &PFS, bool IsMustTailCall,
                                    bool InVarArgsFunc) {
    if (parseToken(lltok::lparen, "expected '(' in call"))
      return true;
  
    while (Lex.getKind() != lltok::rparen) {
      // If this isn't the first argument, we need a comma.
      if (!ArgList.empty() &&
          parseToken(lltok::comma, "expected ',' in argument list"))
        return true;
  
      // parse an ellipsis if this is a musttail call in a variadic function.
      if (Lex.getKind() == lltok::dotdotdot) {
        const char *Msg = "unexpected ellipsis in argument list for ";
        if (!IsMustTailCall)
          return tokError(Twine(Msg) + "non-musttail call");
        if (!InVarArgsFunc)
          return tokError(Twine(Msg) + "musttail call in non-varargs function");
        Lex.Lex();  // Lex the '...', it is purely for readability.
        return parseToken(lltok::rparen, "expected ')' at end of argument list");
      }
  
      // parse the argument.
      LocTy ArgLoc;
      Type *ArgTy = nullptr;
      AttrBuilder ArgAttrs;
      Value *V;
      if (parseType(ArgTy, ArgLoc))
        return true;
  
      if (ArgTy->isMetadataTy()) {
        if (parseMetadataAsValue(V, PFS))
          return true;
      } else {
        // Otherwise, handle normal operands.
        if (parseOptionalParamAttrs(ArgAttrs) || parseValue(ArgTy, V, PFS))
          return true;
      }
      ArgList.push_back(ParamInfo(
          ArgLoc, V, AttributeSet::get(V->getContext(), ArgAttrs)));
    }
  
    if (IsMustTailCall && InVarArgsFunc)
      return tokError("expected '...' at end of argument list for musttail call "
                      "in varargs function");
  
    Lex.Lex();  // Lex the ')'.
    return false;
  }
  
  /// parseRequiredTypeAttr
  ///   ::= attrname(<ty>)
  bool LLParser::parseRequiredTypeAttr(AttrBuilder &B, lltok::Kind AttrToken,
                                       Attribute::AttrKind AttrKind) {
    Type *Ty = nullptr;
    if (!EatIfPresent(AttrToken))
      return true;
    if (!EatIfPresent(lltok::lparen))
      return error(Lex.getLoc(), "expected '('");
    if (parseType(Ty))
      return true;
    if (!EatIfPresent(lltok::rparen))
      return error(Lex.getLoc(), "expected ')'");
  
    B.addTypeAttr(AttrKind, Ty);
    return false;
  }
  
  /// parseOptionalOperandBundles
  ///    ::= /*empty*/
  ///    ::= '[' OperandBundle [, OperandBundle ]* ']'
  ///
  /// OperandBundle
  ///    ::= bundle-tag '(' ')'
  ///    ::= bundle-tag '(' Type Value [, Type Value ]* ')'
  ///
  /// bundle-tag ::= String Constant
  bool LLParser::parseOptionalOperandBundles(
      SmallVectorImpl<OperandBundleDef> &BundleList, PerFunctionState &PFS) {
    LocTy BeginLoc = Lex.getLoc();
    if (!EatIfPresent(lltok::lsquare))
      return false;
  
    while (Lex.getKind() != lltok::rsquare) {
      // If this isn't the first operand bundle, we need a comma.
      if (!BundleList.empty() &&
          parseToken(lltok::comma, "expected ',' in input list"))
        return true;
  
      std::string Tag;
      if (parseStringConstant(Tag))
        return true;
  
      if (parseToken(lltok::lparen, "expected '(' in operand bundle"))
        return true;
  
      std::vector<Value *> Inputs;
      while (Lex.getKind() != lltok::rparen) {
        // If this isn't the first input, we need a comma.
        if (!Inputs.empty() &&
            parseToken(lltok::comma, "expected ',' in input list"))
          return true;
  
        Type *Ty = nullptr;
        Value *Input = nullptr;
        if (parseType(Ty) || parseValue(Ty, Input, PFS))
          return true;
        Inputs.push_back(Input);
      }
  
      BundleList.emplace_back(std::move(Tag), std::move(Inputs));
  
      Lex.Lex(); // Lex the ')'.
    }
  
    if (BundleList.empty())
      return error(BeginLoc, "operand bundle set must not be empty");
  
    Lex.Lex(); // Lex the ']'.
    return false;
  }
  
  /// parseArgumentList - parse the argument list for a function type or function
  /// prototype.
  ///   ::= '(' ArgTypeListI ')'
  /// ArgTypeListI
  ///   ::= /*empty*/
  ///   ::= '...'
  ///   ::= ArgTypeList ',' '...'
  ///   ::= ArgType (',' ArgType)*
  ///
  bool LLParser::parseArgumentList(SmallVectorImpl<ArgInfo> &ArgList,
                                   bool &IsVarArg) {
    unsigned CurValID = 0;
    IsVarArg = false;
    assert(Lex.getKind() == lltok::lparen);
    Lex.Lex(); // eat the (.
  
    if (Lex.getKind() == lltok::rparen) {
      // empty
    } else if (Lex.getKind() == lltok::dotdotdot) {
      IsVarArg = true;
      Lex.Lex();
    } else {
      LocTy TypeLoc = Lex.getLoc();
      Type *ArgTy = nullptr;
      AttrBuilder Attrs;
      std::string Name;
  
      if (parseType(ArgTy) || parseOptionalParamAttrs(Attrs))
        return true;
  
      if (ArgTy->isVoidTy())
        return error(TypeLoc, "argument can not have void type");
  
      if (Lex.getKind() == lltok::LocalVar) {
        Name = Lex.getStrVal();
        Lex.Lex();
      } else if (Lex.getKind() == lltok::LocalVarID) {
        if (Lex.getUIntVal() != CurValID)
          return error(TypeLoc, "argument expected to be numbered '%" +
                                    Twine(CurValID) + "'");
        ++CurValID;
        Lex.Lex();
      }
  
      if (!FunctionType::isValidArgumentType(ArgTy))
        return error(TypeLoc, "invalid type for function argument");
  
      ArgList.emplace_back(TypeLoc, ArgTy,
                           AttributeSet::get(ArgTy->getContext(), Attrs),
                           std::move(Name));
  
      while (EatIfPresent(lltok::comma)) {
        // Handle ... at end of arg list.
        if (EatIfPresent(lltok::dotdotdot)) {
          IsVarArg = true;
          break;
        }
  
        // Otherwise must be an argument type.
        TypeLoc = Lex.getLoc();
        if (parseType(ArgTy) || parseOptionalParamAttrs(Attrs))
          return true;
  
        if (ArgTy->isVoidTy())
          return error(TypeLoc, "argument can not have void type");
  
        if (Lex.getKind() == lltok::LocalVar) {
          Name = Lex.getStrVal();
          Lex.Lex();
        } else {
          if (Lex.getKind() == lltok::LocalVarID) {
            if (Lex.getUIntVal() != CurValID)
              return error(TypeLoc, "argument expected to be numbered '%" +
                                        Twine(CurValID) + "'");
            Lex.Lex();
          }
          ++CurValID;
          Name = "";
        }
  
        if (!ArgTy->isFirstClassType())
          return error(TypeLoc, "invalid type for function argument");
  
        ArgList.emplace_back(TypeLoc, ArgTy,
                             AttributeSet::get(ArgTy->getContext(), Attrs),
                             std::move(Name));
      }
    }
  
    return parseToken(lltok::rparen, "expected ')' at end of argument list");
  }
  
  /// parseFunctionType
  ///  ::= Type ArgumentList OptionalAttrs
  bool LLParser::parseFunctionType(Type *&Result) {
    assert(Lex.getKind() == lltok::lparen);
  
    if (!FunctionType::isValidReturnType(Result))
      return tokError("invalid function return type");
  
    SmallVector<ArgInfo, 8> ArgList;
    bool IsVarArg;
    if (parseArgumentList(ArgList, IsVarArg))
      return true;
  
    // Reject names on the arguments lists.
    for (unsigned i = 0, e = ArgList.size(); i != e; ++i) {
      if (!ArgList[i].Name.empty())
        return error(ArgList[i].Loc, "argument name invalid in function type");
      if (ArgList[i].Attrs.hasAttributes())
        return error(ArgList[i].Loc,
                     "argument attributes invalid in function type");
    }
  
    SmallVector<Type*, 16> ArgListTy;
    for (unsigned i = 0, e = ArgList.size(); i != e; ++i)
      ArgListTy.push_back(ArgList[i].Ty);
  
    Result = FunctionType::get(Result, ArgListTy, IsVarArg);
    return false;
  }
  
  /// parseAnonStructType - parse an anonymous struct type, which is inlined into
  /// other structs.
  bool LLParser::parseAnonStructType(Type *&Result, bool Packed) {
    SmallVector<Type*, 8> Elts;
    if (parseStructBody(Elts))
      return true;
  
    Result = StructType::get(Context, Elts, Packed);
    return false;
  }
  
  /// parseStructDefinition - parse a struct in a 'type' definition.
  bool LLParser::parseStructDefinition(SMLoc TypeLoc, StringRef Name,
                                       std::pair<Type *, LocTy> &Entry,
                                       Type *&ResultTy) {
    // If the type was already defined, diagnose the redefinition.
    if (Entry.first && !Entry.second.isValid())
      return error(TypeLoc, "redefinition of type");
  
    // If we have opaque, just return without filling in the definition for the
    // struct.  This counts as a definition as far as the .ll file goes.
    if (EatIfPresent(lltok::kw_opaque)) {
      // This type is being defined, so clear the location to indicate this.
      Entry.second = SMLoc();
  
      // If this type number has never been uttered, create it.
      if (!Entry.first)
        Entry.first = StructType::create(Context, Name);
      ResultTy = Entry.first;
      return false;
    }
  
    // If the type starts with '<', then it is either a packed struct or a vector.
    bool isPacked = EatIfPresent(lltok::less);
  
    // If we don't have a struct, then we have a random type alias, which we
    // accept for compatibility with old files.  These types are not allowed to be
    // forward referenced and not allowed to be recursive.
    if (Lex.getKind() != lltok::lbrace) {
      if (Entry.first)
        return error(TypeLoc, "forward references to non-struct type");
  
      ResultTy = nullptr;
      if (isPacked)
        return parseArrayVectorType(ResultTy, true);
      return parseType(ResultTy);
    }
  
    // This type is being defined, so clear the location to indicate this.
    Entry.second = SMLoc();
  
    // If this type number has never been uttered, create it.
    if (!Entry.first)
      Entry.first = StructType::create(Context, Name);
  
    StructType *STy = cast<StructType>(Entry.first);
  
    SmallVector<Type*, 8> Body;
    if (parseStructBody(Body) ||
        (isPacked && parseToken(lltok::greater, "expected '>' in packed struct")))
      return true;
  
    STy->setBody(Body, isPacked);
    ResultTy = STy;
    return false;
  }
  
  /// parseStructType: Handles packed and unpacked types.  </> parsed elsewhere.
  ///   StructType
  ///     ::= '{' '}'
  ///     ::= '{' Type (',' Type)* '}'
  ///     ::= '<' '{' '}' '>'
  ///     ::= '<' '{' Type (',' Type)* '}' '>'
  bool LLParser::parseStructBody(SmallVectorImpl<Type *> &Body) {
    assert(Lex.getKind() == lltok::lbrace);
    Lex.Lex(); // Consume the '{'
  
    // Handle the empty struct.
    if (EatIfPresent(lltok::rbrace))
      return false;
  
    LocTy EltTyLoc = Lex.getLoc();
    Type *Ty = nullptr;
    if (parseType(Ty))
      return true;
    Body.push_back(Ty);
  
    if (!StructType::isValidElementType(Ty))
      return error(EltTyLoc, "invalid element type for struct");
  
    while (EatIfPresent(lltok::comma)) {
      EltTyLoc = Lex.getLoc();
      if (parseType(Ty))
        return true;
  
      if (!StructType::isValidElementType(Ty))
        return error(EltTyLoc, "invalid element type for struct");
  
      Body.push_back(Ty);
    }
  
    return parseToken(lltok::rbrace, "expected '}' at end of struct");
  }
  
  /// parseArrayVectorType - parse an array or vector type, assuming the first
  /// token has already been consumed.
  ///   Type
  ///     ::= '[' APSINTVAL 'x' Types ']'
  ///     ::= '<' APSINTVAL 'x' Types '>'
  ///     ::= '<' 'vscale' 'x' APSINTVAL 'x' Types '>'
  bool LLParser::parseArrayVectorType(Type *&Result, bool IsVector) {
    bool Scalable = false;
  
    if (IsVector && Lex.getKind() == lltok::kw_vscale) {
      Lex.Lex(); // consume the 'vscale'
      if (parseToken(lltok::kw_x, "expected 'x' after vscale"))
        return true;
  
      Scalable = true;
    }
  
    if (Lex.getKind() != lltok::APSInt || Lex.getAPSIntVal().isSigned() ||
        Lex.getAPSIntVal().getBitWidth() > 64)
      return tokError("expected number in address space");
  
    LocTy SizeLoc = Lex.getLoc();
    uint64_t Size = Lex.getAPSIntVal().getZExtValue();
    Lex.Lex();
  
    if (parseToken(lltok::kw_x, "expected 'x' after element count"))
      return true;
  
    LocTy TypeLoc = Lex.getLoc();
    Type *EltTy = nullptr;
    if (parseType(EltTy))
      return true;
  
    if (parseToken(IsVector ? lltok::greater : lltok::rsquare,
                   "expected end of sequential type"))
      return true;
  
    if (IsVector) {
      if (Size == 0)
        return error(SizeLoc, "zero element vector is illegal");
      if ((unsigned)Size != Size)
        return error(SizeLoc, "size too large for vector");
      if (!VectorType::isValidElementType(EltTy))
        return error(TypeLoc, "invalid vector element type");
      Result = VectorType::get(EltTy, unsigned(Size), Scalable);
    } else {
      if (!ArrayType::isValidElementType(EltTy))
        return error(TypeLoc, "invalid array element type");
      Result = ArrayType::get(EltTy, Size);
    }
    return false;
  }
  
  //===----------------------------------------------------------------------===//
  // Function Semantic Analysis.
  //===----------------------------------------------------------------------===//
  
  LLParser::PerFunctionState::PerFunctionState(LLParser &p, Function &f,
                                               int functionNumber)
    : P(p), F(f), FunctionNumber(functionNumber) {
  
    // Insert unnamed arguments into the NumberedVals list.
    for (Argument &A : F.args())
      if (!A.hasName())
        NumberedVals.push_back(&A);
  }
  
  LLParser::PerFunctionState::~PerFunctionState() {
    // If there were any forward referenced non-basicblock values, delete them.
  
    for (const auto &P : ForwardRefVals) {
      if (isa<BasicBlock>(P.second.first))
        continue;
      P.second.first->replaceAllUsesWith(
          UndefValue::get(P.second.first->getType()));
      P.second.first->deleteValue();
    }
  
    for (const auto &P : ForwardRefValIDs) {
      if (isa<BasicBlock>(P.second.first))
        continue;
      P.second.first->replaceAllUsesWith(
          UndefValue::get(P.second.first->getType()));
      P.second.first->deleteValue();
    }
  }
  
  bool LLParser::PerFunctionState::finishFunction() {
    if (!ForwardRefVals.empty())
      return P.error(ForwardRefVals.begin()->second.second,
                     "use of undefined value '%" + ForwardRefVals.begin()->first +
                         "'");
    if (!ForwardRefValIDs.empty())
      return P.error(ForwardRefValIDs.begin()->second.second,
                     "use of undefined value '%" +
                         Twine(ForwardRefValIDs.begin()->first) + "'");
    return false;
  }
  
  /// getVal - Get a value with the specified name or ID, creating a
  /// forward reference record if needed.  This can return null if the value
  /// exists but does not have the right type.
  Value *LLParser::PerFunctionState::getVal(const std::string &Name, Type *Ty,
                                            LocTy Loc) {
    // Look this name up in the normal function symbol table.
    Value *Val = F.getValueSymbolTable()->lookup(Name);
  
    // If this is a forward reference for the value, see if we already created a
    // forward ref record.
    if (!Val) {
      auto I = ForwardRefVals.find(Name);
      if (I != ForwardRefVals.end())
        Val = I->second.first;
    }
  
    // If we have the value in the symbol table or fwd-ref table, return it.
    if (Val)
      return P.checkValidVariableType(Loc, "%" + Name, Ty, Val);
  
    // Don't make placeholders with invalid type.
    if (!Ty->isFirstClassType()) {
      P.error(Loc, "invalid use of a non-first-class type");
      return nullptr;
    }
  
    // Otherwise, create a new forward reference for this value and remember it.
    Value *FwdVal;
    if (Ty->isLabelTy()) {
      FwdVal = BasicBlock::Create(F.getContext(), Name, &F);
    } else {
      FwdVal = new Argument(Ty, Name);
    }
  
    ForwardRefVals[Name] = std::make_pair(FwdVal, Loc);
    return FwdVal;
  }
  
  Value *LLParser::PerFunctionState::getVal(unsigned ID, Type *Ty, LocTy Loc) {
    // Look this name up in the normal function symbol table.
    Value *Val = ID < NumberedVals.size() ? NumberedVals[ID] : nullptr;
  
    // If this is a forward reference for the value, see if we already created a
    // forward ref record.
    if (!Val) {
      auto I = ForwardRefValIDs.find(ID);
      if (I != ForwardRefValIDs.end())
        Val = I->second.first;
    }
  
    // If we have the value in the symbol table or fwd-ref table, return it.
    if (Val)
      return P.checkValidVariableType(Loc, "%" + Twine(ID), Ty, Val);
  
    if (!Ty->isFirstClassType()) {
      P.error(Loc, "invalid use of a non-first-class type");
      return nullptr;
    }
  
    // Otherwise, create a new forward reference for this value and remember it.
    Value *FwdVal;
    if (Ty->isLabelTy()) {
      FwdVal = BasicBlock::Create(F.getContext(), "", &F);
    } else {
      FwdVal = new Argument(Ty);
    }
  
    ForwardRefValIDs[ID] = std::make_pair(FwdVal, Loc);
    return FwdVal;
  }
  
  /// setInstName - After an instruction is parsed and inserted into its
  /// basic block, this installs its name.
  bool LLParser::PerFunctionState::setInstName(int NameID,
                                               const std::string &NameStr,
                                               LocTy NameLoc, Instruction *Inst) {
    // If this instruction has void type, it cannot have a name or ID specified.
    if (Inst->getType()->isVoidTy()) {
      if (NameID != -1 || !NameStr.empty())
        return P.error(NameLoc, "instructions returning void cannot have a name");
      return false;
    }
  
    // If this was a numbered instruction, verify that the instruction is the
    // expected value and resolve any forward references.
    if (NameStr.empty()) {
      // If neither a name nor an ID was specified, just use the next ID.
      if (NameID == -1)
        NameID = NumberedVals.size();
  
      if (unsigned(NameID) != NumberedVals.size())
        return P.error(NameLoc, "instruction expected to be numbered '%" +
                                    Twine(NumberedVals.size()) + "'");
  
      auto FI = ForwardRefValIDs.find(NameID);
      if (FI != ForwardRefValIDs.end()) {
        Value *Sentinel = FI->second.first;
        if (Sentinel->getType() != Inst->getType())
          return P.error(NameLoc, "instruction forward referenced with type '" +
                                      getTypeString(FI->second.first->getType()) +
                                      "'");
  
        Sentinel->replaceAllUsesWith(Inst);
        Sentinel->deleteValue();
        ForwardRefValIDs.erase(FI);
      }
  
      NumberedVals.push_back(Inst);
      return false;
    }
  
    // Otherwise, the instruction had a name.  Resolve forward refs and set it.
    auto FI = ForwardRefVals.find(NameStr);
    if (FI != ForwardRefVals.end()) {
      Value *Sentinel = FI->second.first;
      if (Sentinel->getType() != Inst->getType())
        return P.error(NameLoc, "instruction forward referenced with type '" +
                                    getTypeString(FI->second.first->getType()) +
                                    "'");
  
      Sentinel->replaceAllUsesWith(Inst);
      Sentinel->deleteValue();
      ForwardRefVals.erase(FI);
    }
  
    // Set the name on the instruction.
    Inst->setName(NameStr);
  
    if (Inst->getName() != NameStr)
      return P.error(NameLoc, "multiple definition of local value named '" +
                                  NameStr + "'");
    return false;
  }
  
  /// getBB - Get a basic block with the specified name or ID, creating a
  /// forward reference record if needed.
  BasicBlock *LLParser::PerFunctionState::getBB(const std::string &Name,
                                                LocTy Loc) {
    return dyn_cast_or_null<BasicBlock>(
        getVal(Name, Type::getLabelTy(F.getContext()), Loc));
  }
  
  BasicBlock *LLParser::PerFunctionState::getBB(unsigned ID, LocTy Loc) {
    return dyn_cast_or_null<BasicBlock>(
        getVal(ID, Type::getLabelTy(F.getContext()), Loc));
  }
  
  /// defineBB - Define the specified basic block, which is either named or
  /// unnamed.  If there is an error, this returns null otherwise it returns
  /// the block being defined.
  BasicBlock *LLParser::PerFunctionState::defineBB(const std::string &Name,
                                                   int NameID, LocTy Loc) {
    BasicBlock *BB;
    if (Name.empty()) {
      if (NameID != -1 && unsigned(NameID) != NumberedVals.size()) {
        P.error(Loc, "label expected to be numbered '" +
                         Twine(NumberedVals.size()) + "'");
        return nullptr;
      }
      BB = getBB(NumberedVals.size(), Loc);
      if (!BB) {
        P.error(Loc, "unable to create block numbered '" +
                         Twine(NumberedVals.size()) + "'");
        return nullptr;
      }
    } else {
      BB = getBB(Name, Loc);
      if (!BB) {
        P.error(Loc, "unable to create block named '" + Name + "'");
        return nullptr;
      }
    }
  
    // Move the block to the end of the function.  Forward ref'd blocks are
    // inserted wherever they happen to be referenced.
    F.getBasicBlockList().splice(F.end(), F.getBasicBlockList(), BB);
  
    // Remove the block from forward ref sets.
    if (Name.empty()) {
      ForwardRefValIDs.erase(NumberedVals.size());
      NumberedVals.push_back(BB);
    } else {
      // BB forward references are already in the function symbol table.
      ForwardRefVals.erase(Name);
    }
  
    return BB;
  }
  
  //===----------------------------------------------------------------------===//
  // Constants.
  //===----------------------------------------------------------------------===//
  
  /// parseValID - parse an abstract value that doesn't necessarily have a
  /// type implied.  For example, if we parse "4" we don't know what integer type
  /// it has.  The value will later be combined with its type and checked for
  /// basic correctness.  PFS is used to convert function-local operands of
  /// metadata (since metadata operands are not just parsed here but also
  /// converted to values). PFS can be null when we are not parsing metadata
  /// values inside a function.
  bool LLParser::parseValID(ValID &ID, PerFunctionState *PFS, Type *ExpectedTy) {
    ID.Loc = Lex.getLoc();
    switch (Lex.getKind()) {
    default:
      return tokError("expected value token");
    case lltok::GlobalID:  // @42
      ID.UIntVal = Lex.getUIntVal();
      ID.Kind = ValID::t_GlobalID;
      break;
    case lltok::GlobalVar:  // @foo
      ID.StrVal = Lex.getStrVal();
      ID.Kind = ValID::t_GlobalName;
      break;
    case lltok::LocalVarID:  // %42
      ID.UIntVal = Lex.getUIntVal();
      ID.Kind = ValID::t_LocalID;
      break;
    case lltok::LocalVar:  // %foo
      ID.StrVal = Lex.getStrVal();
      ID.Kind = ValID::t_LocalName;
      break;
    case lltok::APSInt:
      ID.APSIntVal = Lex.getAPSIntVal();
      ID.Kind = ValID::t_APSInt;
      break;
    case lltok::APFloat:
      ID.APFloatVal = Lex.getAPFloatVal();
      ID.Kind = ValID::t_APFloat;
      break;
    case lltok::kw_true:
      ID.ConstantVal = ConstantInt::getTrue(Context);
      ID.Kind = ValID::t_Constant;
      break;
    case lltok::kw_false:
      ID.ConstantVal = ConstantInt::getFalse(Context);
      ID.Kind = ValID::t_Constant;
      break;
    case lltok::kw_null: ID.Kind = ValID::t_Null; break;
    case lltok::kw_undef: ID.Kind = ValID::t_Undef; break;
    case lltok::kw_poison: ID.Kind = ValID::t_Poison; break;
    case lltok::kw_zeroinitializer: ID.Kind = ValID::t_Zero; break;
    case lltok::kw_none: ID.Kind = ValID::t_None; break;
  
    case lltok::lbrace: {
      // ValID ::= '{' ConstVector '}'
      Lex.Lex();
      SmallVector<Constant*, 16> Elts;
      if (parseGlobalValueVector(Elts) ||
          parseToken(lltok::rbrace, "expected end of struct constant"))
        return true;
  
      ID.ConstantStructElts = std::make_unique<Constant *[]>(Elts.size());
      ID.UIntVal = Elts.size();
      memcpy(ID.ConstantStructElts.get(), Elts.data(),
             Elts.size() * sizeof(Elts[0]));
      ID.Kind = ValID::t_ConstantStruct;
      return false;
    }
    case lltok::less: {
      // ValID ::= '<' ConstVector '>'         --> Vector.
      // ValID ::= '<' '{' ConstVector '}' '>' --> Packed Struct.
      Lex.Lex();
      bool isPackedStruct = EatIfPresent(lltok::lbrace);
  
      SmallVector<Constant*, 16> Elts;
      LocTy FirstEltLoc = Lex.getLoc();
      if (parseGlobalValueVector(Elts) ||
          (isPackedStruct &&
           parseToken(lltok::rbrace, "expected end of packed struct")) ||
          parseToken(lltok::greater, "expected end of constant"))
        return true;
  
      if (isPackedStruct) {
        ID.ConstantStructElts = std::make_unique<Constant *[]>(Elts.size());
        memcpy(ID.ConstantStructElts.get(), Elts.data(),
               Elts.size() * sizeof(Elts[0]));
        ID.UIntVal = Elts.size();
        ID.Kind = ValID::t_PackedConstantStruct;
        return false;
      }
  
      if (Elts.empty())
        return error(ID.Loc, "constant vector must not be empty");
  
      if (!Elts[0]->getType()->isIntegerTy() &&
          !Elts[0]->getType()->isFloatingPointTy() &&
          !Elts[0]->getType()->isPointerTy())
        return error(
            FirstEltLoc,
            "vector elements must have integer, pointer or floating point type");
  
      // Verify that all the vector elements have the same type.
      for (unsigned i = 1, e = Elts.size(); i != e; ++i)
        if (Elts[i]->getType() != Elts[0]->getType())
          return error(FirstEltLoc, "vector element #" + Twine(i) +
                                        " is not of type '" +
                                        getTypeString(Elts[0]->getType()));
  
      ID.ConstantVal = ConstantVector::get(Elts);
      ID.Kind = ValID::t_Constant;
      return false;
    }
    case lltok::lsquare: {   // Array Constant
      Lex.Lex();
      SmallVector<Constant*, 16> Elts;
      LocTy FirstEltLoc = Lex.getLoc();
      if (parseGlobalValueVector(Elts) ||
          parseToken(lltok::rsquare, "expected end of array constant"))
        return true;
  
      // Handle empty element.
      if (Elts.empty()) {
        // Use undef instead of an array because it's inconvenient to determine
        // the element type at this point, there being no elements to examine.
        ID.Kind = ValID::t_EmptyArray;
        return false;
      }
  
      if (!Elts[0]->getType()->isFirstClassType())
        return error(FirstEltLoc, "invalid array element type: " +
                                      getTypeString(Elts[0]->getType()));
  
      ArrayType *ATy = ArrayType::get(Elts[0]->getType(), Elts.size());
  
      // Verify all elements are correct type!
      for (unsigned i = 0, e = Elts.size(); i != e; ++i) {
        if (Elts[i]->getType() != Elts[0]->getType())
          return error(FirstEltLoc, "array element #" + Twine(i) +
                                        " is not of type '" +
                                        getTypeString(Elts[0]->getType()));
      }
  
      ID.ConstantVal = ConstantArray::get(ATy, Elts);
      ID.Kind = ValID::t_Constant;
      return false;
    }
    case lltok::kw_c:  // c "foo"
      Lex.Lex();
      ID.ConstantVal = ConstantDataArray::getString(Context, Lex.getStrVal(),
                                                    false);
      if (parseToken(lltok::StringConstant, "expected string"))
        return true;
      ID.Kind = ValID::t_Constant;
      return false;
  
    case lltok::kw_asm: {
      // ValID ::= 'asm' SideEffect? AlignStack? IntelDialect? STRINGCONSTANT ','
      //             STRINGCONSTANT
      bool HasSideEffect, AlignStack, AsmDialect, CanThrow;
      Lex.Lex();
      if (parseOptionalToken(lltok::kw_sideeffect, HasSideEffect) ||
          parseOptionalToken(lltok::kw_alignstack, AlignStack) ||
          parseOptionalToken(lltok::kw_inteldialect, AsmDialect) ||
          parseOptionalToken(lltok::kw_unwind, CanThrow) ||
          parseStringConstant(ID.StrVal) ||
          parseToken(lltok::comma, "expected comma in inline asm expression") ||
          parseToken(lltok::StringConstant, "expected constraint string"))
        return true;
      ID.StrVal2 = Lex.getStrVal();
      ID.UIntVal = unsigned(HasSideEffect) | (unsigned(AlignStack) << 1) |
                   (unsigned(AsmDialect) << 2) | (unsigned(CanThrow) << 3);
      ID.Kind = ValID::t_InlineAsm;
      return false;
    }
  
    case lltok::kw_blockaddress: {
      // ValID ::= 'blockaddress' '(' @foo ',' %bar ')'
      Lex.Lex();
  
      ValID Fn, Label;
  
      if (parseToken(lltok::lparen, "expected '(' in block address expression") ||
          parseValID(Fn, PFS) ||
          parseToken(lltok::comma,
                     "expected comma in block address expression") ||
          parseValID(Label, PFS) ||
          parseToken(lltok::rparen, "expected ')' in block address expression"))
        return true;
  
      if (Fn.Kind != ValID::t_GlobalID && Fn.Kind != ValID::t_GlobalName)
        return error(Fn.Loc, "expected function name in blockaddress");
      if (Label.Kind != ValID::t_LocalID && Label.Kind != ValID::t_LocalName)
        return error(Label.Loc, "expected basic block name in blockaddress");
  
      // Try to find the function (but skip it if it's forward-referenced).
      GlobalValue *GV = nullptr;
      if (Fn.Kind == ValID::t_GlobalID) {
        if (Fn.UIntVal < NumberedVals.size())
          GV = NumberedVals[Fn.UIntVal];
      } else if (!ForwardRefVals.count(Fn.StrVal)) {
        GV = M->getNamedValue(Fn.StrVal);
      }
      Function *F = nullptr;
      if (GV) {
        // Confirm that it's actually a function with a definition.
        if (!isa<Function>(GV))
          return error(Fn.Loc, "expected function name in blockaddress");
        F = cast<Function>(GV);
        if (F->isDeclaration())
          return error(Fn.Loc, "cannot take blockaddress inside a declaration");
      }
  
      if (!F) {
        // Make a global variable as a placeholder for this reference.
        GlobalValue *&FwdRef =
            ForwardRefBlockAddresses.insert(std::make_pair(
                                                std::move(Fn),
                                                std::map<ValID, GlobalValue *>()))
                .first->second.insert(std::make_pair(std::move(Label), nullptr))
                .first->second;
        if (!FwdRef) {
          unsigned FwdDeclAS;
          if (ExpectedTy) {
            // If we know the type that the blockaddress is being assigned to,
            // we can use the address space of that type.
            if (!ExpectedTy->isPointerTy())
              return error(ID.Loc,
                           "type of blockaddress must be a pointer and not '" +
                               getTypeString(ExpectedTy) + "'");
            FwdDeclAS = ExpectedTy->getPointerAddressSpace();
          } else if (PFS) {
            // Otherwise, we default the address space of the current function.
            FwdDeclAS = PFS->getFunction().getAddressSpace();
          } else {
            llvm_unreachable("Unknown address space for blockaddress");
          }
          FwdRef = new GlobalVariable(
              *M, Type::getInt8Ty(Context), false, GlobalValue::InternalLinkage,
              nullptr, "", nullptr, GlobalValue::NotThreadLocal, FwdDeclAS);
        }
  
        ID.ConstantVal = FwdRef;
        ID.Kind = ValID::t_Constant;
        return false;
      }
  
      // We found the function; now find the basic block.  Don't use PFS, since we
      // might be inside a constant expression.
      BasicBlock *BB;
      if (BlockAddressPFS && F == &BlockAddressPFS->getFunction()) {
        if (Label.Kind == ValID::t_LocalID)
          BB = BlockAddressPFS->getBB(Label.UIntVal, Label.Loc);
        else
          BB = BlockAddressPFS->getBB(Label.StrVal, Label.Loc);
        if (!BB)
          return error(Label.Loc, "referenced value is not a basic block");
      } else {
        if (Label.Kind == ValID::t_LocalID)
          return error(Label.Loc, "cannot take address of numeric label after "
                                  "the function is defined");
        BB = dyn_cast_or_null<BasicBlock>(
            F->getValueSymbolTable()->lookup(Label.StrVal));
        if (!BB)
          return error(Label.Loc, "referenced value is not a basic block");
      }
  
      ID.ConstantVal = BlockAddress::get(F, BB);
      ID.Kind = ValID::t_Constant;
      return false;
    }
  
    case lltok::kw_dso_local_equivalent: {
      // ValID ::= 'dso_local_equivalent' @foo
      Lex.Lex();
  
      ValID Fn;
  
      if (parseValID(Fn, PFS))
        return true;
  
      if (Fn.Kind != ValID::t_GlobalID && Fn.Kind != ValID::t_GlobalName)
        return error(Fn.Loc,
                     "expected global value name in dso_local_equivalent");
  
      // Try to find the function (but skip it if it's forward-referenced).
      GlobalValue *GV = nullptr;
      if (Fn.Kind == ValID::t_GlobalID) {
        if (Fn.UIntVal < NumberedVals.size())
          GV = NumberedVals[Fn.UIntVal];
      } else if (!ForwardRefVals.count(Fn.StrVal)) {
        GV = M->getNamedValue(Fn.StrVal);
      }
  
      assert(GV && "Could not find a corresponding global variable");
  
      if (!GV->getValueType()->isFunctionTy())
        return error(Fn.Loc, "expected a function, alias to function, or ifunc "
                             "in dso_local_equivalent");
  
      ID.ConstantVal = DSOLocalEquivalent::get(GV);
      ID.Kind = ValID::t_Constant;
      return false;
    }
  
    case lltok::kw_trunc:
    case lltok::kw_zext:
    case lltok::kw_sext:
    case lltok::kw_fptrunc:
    case lltok::kw_fpext:
    case lltok::kw_bitcast:
    case lltok::kw_addrspacecast:
    case lltok::kw_uitofp:
    case lltok::kw_sitofp:
    case lltok::kw_fptoui:
    case lltok::kw_fptosi:
    case lltok::kw_inttoptr:
    case lltok::kw_ptrtoint: {
      unsigned Opc = Lex.getUIntVal();
      Type *DestTy = nullptr;
      Constant *SrcVal;
      Lex.Lex();
      if (parseToken(lltok::lparen, "expected '(' after constantexpr cast") ||
          parseGlobalTypeAndValue(SrcVal) ||
          parseToken(lltok::kw_to, "expected 'to' in constantexpr cast") ||
          parseType(DestTy) ||
          parseToken(lltok::rparen, "expected ')' at end of constantexpr cast"))
        return true;
      if (!CastInst::castIsValid((Instruction::CastOps)Opc, SrcVal, DestTy))
        return error(ID.Loc, "invalid cast opcode for cast from '" +
                                 getTypeString(SrcVal->getType()) + "' to '" +
                                 getTypeString(DestTy) + "'");
      ID.ConstantVal = ConstantExpr::getCast((Instruction::CastOps)Opc,
                                                   SrcVal, DestTy);
      ID.Kind = ValID::t_Constant;
      return false;
    }
    case lltok::kw_extractvalue: {
      Lex.Lex();
      Constant *Val;
      SmallVector<unsigned, 4> Indices;
      if (parseToken(lltok::lparen,
                     "expected '(' in extractvalue constantexpr") ||
          parseGlobalTypeAndValue(Val) || parseIndexList(Indices) ||
          parseToken(lltok::rparen, "expected ')' in extractvalue constantexpr"))
        return true;
  
      if (!Val->getType()->isAggregateType())
        return error(ID.Loc, "extractvalue operand must be aggregate type");
      if (!ExtractValueInst::getIndexedType(Val->getType(), Indices))
        return error(ID.Loc, "invalid indices for extractvalue");
      ID.ConstantVal = ConstantExpr::getExtractValue(Val, Indices);
      ID.Kind = ValID::t_Constant;
      return false;
    }
    case lltok::kw_insertvalue: {
      Lex.Lex();
      Constant *Val0, *Val1;
      SmallVector<unsigned, 4> Indices;
      if (parseToken(lltok::lparen, "expected '(' in insertvalue constantexpr") ||
          parseGlobalTypeAndValue(Val0) ||
          parseToken(lltok::comma,
                     "expected comma in insertvalue constantexpr") ||
          parseGlobalTypeAndValue(Val1) || parseIndexList(Indices) ||
          parseToken(lltok::rparen, "expected ')' in insertvalue constantexpr"))
        return true;
      if (!Val0->getType()->isAggregateType())
        return error(ID.Loc, "insertvalue operand must be aggregate type");
      Type *IndexedType =
          ExtractValueInst::getIndexedType(Val0->getType(), Indices);
      if (!IndexedType)
        return error(ID.Loc, "invalid indices for insertvalue");
      if (IndexedType != Val1->getType())
        return error(ID.Loc, "insertvalue operand and field disagree in type: '" +
                                 getTypeString(Val1->getType()) +
                                 "' instead of '" + getTypeString(IndexedType) +
                                 "'");
      ID.ConstantVal = ConstantExpr::getInsertValue(Val0, Val1, Indices);
      ID.Kind = ValID::t_Constant;
      return false;
    }
    case lltok::kw_icmp:
    case lltok::kw_fcmp: {
      unsigned PredVal, Opc = Lex.getUIntVal();
      Constant *Val0, *Val1;
      Lex.Lex();
      if (parseCmpPredicate(PredVal, Opc) ||
          parseToken(lltok::lparen, "expected '(' in compare constantexpr") ||
          parseGlobalTypeAndValue(Val0) ||
          parseToken(lltok::comma, "expected comma in compare constantexpr") ||
          parseGlobalTypeAndValue(Val1) ||
          parseToken(lltok::rparen, "expected ')' in compare constantexpr"))
        return true;
  
      if (Val0->getType() != Val1->getType())
        return error(ID.Loc, "compare operands must have the same type");
  
      CmpInst::Predicate Pred = (CmpInst::Predicate)PredVal;
  
      if (Opc == Instruction::FCmp) {
        if (!Val0->getType()->isFPOrFPVectorTy())
          return error(ID.Loc, "fcmp requires floating point operands");
        ID.ConstantVal = ConstantExpr::getFCmp(Pred, Val0, Val1);
      } else {
        assert(Opc == Instruction::ICmp && "Unexpected opcode for CmpInst!");
        if (!Val0->getType()->isIntOrIntVectorTy() &&
            !Val0->getType()->isPtrOrPtrVectorTy())
          return error(ID.Loc, "icmp requires pointer or integer operands");
        ID.ConstantVal = ConstantExpr::getICmp(Pred, Val0, Val1);
      }
      ID.Kind = ValID::t_Constant;
      return false;
    }
  
    // Unary Operators.
    case lltok::kw_fneg: {
      unsigned Opc = Lex.getUIntVal();
      Constant *Val;
      Lex.Lex();
      if (parseToken(lltok::lparen, "expected '(' in unary constantexpr") ||
          parseGlobalTypeAndValue(Val) ||
          parseToken(lltok::rparen, "expected ')' in unary constantexpr"))
        return true;
  
      // Check that the type is valid for the operator.
      switch (Opc) {
      case Instruction::FNeg:
        if (!Val->getType()->isFPOrFPVectorTy())
          return error(ID.Loc, "constexpr requires fp operands");
        break;
      default: llvm_unreachable("Unknown unary operator!");
      }
      unsigned Flags = 0;
      Constant *C = ConstantExpr::get(Opc, Val, Flags);
      ID.ConstantVal = C;
      ID.Kind = ValID::t_Constant;
      return false;
    }
    // Binary Operators.
    case lltok::kw_add:
    case lltok::kw_fadd:
    case lltok::kw_sub:
    case lltok::kw_fsub:
    case lltok::kw_mul:
    case lltok::kw_fmul:
    case lltok::kw_udiv:
    case lltok::kw_sdiv:
    case lltok::kw_fdiv:
    case lltok::kw_urem:
    case lltok::kw_srem:
    case lltok::kw_frem:
    case lltok::kw_shl:
    case lltok::kw_lshr:
    case lltok::kw_ashr: {
      bool NUW = false;
      bool NSW = false;
      bool Exact = false;
      unsigned Opc = Lex.getUIntVal();
      Constant *Val0, *Val1;
      Lex.Lex();
      if (Opc == Instruction::Add || Opc == Instruction::Sub ||
          Opc == Instruction::Mul || Opc == Instruction::Shl) {
        if (EatIfPresent(lltok::kw_nuw))
          NUW = true;
        if (EatIfPresent(lltok::kw_nsw)) {
          NSW = true;
          if (EatIfPresent(lltok::kw_nuw))
            NUW = true;
        }
      } else if (Opc == Instruction::SDiv || Opc == Instruction::UDiv ||
                 Opc == Instruction::LShr || Opc == Instruction::AShr) {
        if (EatIfPresent(lltok::kw_exact))
          Exact = true;
      }
      if (parseToken(lltok::lparen, "expected '(' in binary constantexpr") ||
          parseGlobalTypeAndValue(Val0) ||
          parseToken(lltok::comma, "expected comma in binary constantexpr") ||
          parseGlobalTypeAndValue(Val1) ||
          parseToken(lltok::rparen, "expected ')' in binary constantexpr"))
        return true;
      if (Val0->getType() != Val1->getType())
        return error(ID.Loc, "operands of constexpr must have same type");
      // Check that the type is valid for the operator.
      switch (Opc) {
      case Instruction::Add:
      case Instruction::Sub:
      case Instruction::Mul:
      case Instruction::UDiv:
      case Instruction::SDiv:
      case Instruction::URem:
      case Instruction::SRem:
      case Instruction::Shl:
      case Instruction::AShr:
      case Instruction::LShr:
        if (!Val0->getType()->isIntOrIntVectorTy())
          return error(ID.Loc, "constexpr requires integer operands");
        break;
      case Instruction::FAdd:
      case Instruction::FSub:
      case Instruction::FMul:
      case Instruction::FDiv:
      case Instruction::FRem:
        if (!Val0->getType()->isFPOrFPVectorTy())
          return error(ID.Loc, "constexpr requires fp operands");
        break;
      default: llvm_unreachable("Unknown binary operator!");
      }
      unsigned Flags = 0;
      if (NUW)   Flags |= OverflowingBinaryOperator::NoUnsignedWrap;
      if (NSW)   Flags |= OverflowingBinaryOperator::NoSignedWrap;
      if (Exact) Flags |= PossiblyExactOperator::IsExact;
      Constant *C = ConstantExpr::get(Opc, Val0, Val1, Flags);
      ID.ConstantVal = C;
      ID.Kind = ValID::t_Constant;
      return false;
    }
  
    // Logical Operations
    case lltok::kw_and:
    case lltok::kw_or:
    case lltok::kw_xor: {
      unsigned Opc = Lex.getUIntVal();
      Constant *Val0, *Val1;
      Lex.Lex();
      if (parseToken(lltok::lparen, "expected '(' in logical constantexpr") ||
          parseGlobalTypeAndValue(Val0) ||
          parseToken(lltok::comma, "expected comma in logical constantexpr") ||
          parseGlobalTypeAndValue(Val1) ||
          parseToken(lltok::rparen, "expected ')' in logical constantexpr"))
        return true;
      if (Val0->getType() != Val1->getType())
        return error(ID.Loc, "operands of constexpr must have same type");
      if (!Val0->getType()->isIntOrIntVectorTy())
        return error(ID.Loc,
                     "constexpr requires integer or integer vector operands");
      ID.ConstantVal = ConstantExpr::get(Opc, Val0, Val1);
      ID.Kind = ValID::t_Constant;
      return false;
    }
  
    case lltok::kw_getelementptr:
    case lltok::kw_shufflevector:
    case lltok::kw_insertelement:
    case lltok::kw_extractelement:
    case lltok::kw_select: {
      unsigned Opc = Lex.getUIntVal();
      SmallVector<Constant*, 16> Elts;
      bool InBounds = false;
      Type *Ty;
      Lex.Lex();
  
      if (Opc == Instruction::GetElementPtr)
        InBounds = EatIfPresent(lltok::kw_inbounds);
  
      if (parseToken(lltok::lparen, "expected '(' in constantexpr"))
        return true;
  
      LocTy ExplicitTypeLoc = Lex.getLoc();
      if (Opc == Instruction::GetElementPtr) {
        if (parseType(Ty) ||
            parseToken(lltok::comma, "expected comma after getelementptr's type"))
          return true;
      }
  
      Optional<unsigned> InRangeOp;
      if (parseGlobalValueVector(
              Elts, Opc == Instruction::GetElementPtr ? &InRangeOp : nullptr) ||
          parseToken(lltok::rparen, "expected ')' in constantexpr"))
        return true;
  
      if (Opc == Instruction::GetElementPtr) {
        if (Elts.size() == 0 ||
            !Elts[0]->getType()->isPtrOrPtrVectorTy())
          return error(ID.Loc, "base of getelementptr must be a pointer");
  
        Type *BaseType = Elts[0]->getType();
        auto *BasePointerType = cast<PointerType>(BaseType->getScalarType());
        if (!BasePointerType->isOpaqueOrPointeeTypeMatches(Ty)) {
          return error(
              ExplicitTypeLoc,
              typeComparisonErrorMessage(
                  "explicit pointee type doesn't match operand's pointee type",
                  Ty, BasePointerType->getElementType()));
        }
  
        unsigned GEPWidth =
            BaseType->isVectorTy()
                ? cast<FixedVectorType>(BaseType)->getNumElements()
                : 0;
  
        ArrayRef<Constant *> Indices(Elts.begin() + 1, Elts.end());
        for (Constant *Val : Indices) {
          Type *ValTy = Val->getType();
          if (!ValTy->isIntOrIntVectorTy())
            return error(ID.Loc, "getelementptr index must be an integer");
          if (auto *ValVTy = dyn_cast<VectorType>(ValTy)) {
            unsigned ValNumEl = cast<FixedVectorType>(ValVTy)->getNumElements();
            if (GEPWidth && (ValNumEl != GEPWidth))
              return error(
                  ID.Loc,
                  "getelementptr vector index has a wrong number of elements");
            // GEPWidth may have been unknown because the base is a scalar,
            // but it is known now.
            GEPWidth = ValNumEl;
          }
        }
  
        SmallPtrSet<Type*, 4> Visited;
        if (!Indices.empty() && !Ty->isSized(&Visited))
          return error(ID.Loc, "base element of getelementptr must be sized");
  
        if (!GetElementPtrInst::getIndexedType(Ty, Indices))
          return error(ID.Loc, "invalid getelementptr indices");
  
        if (InRangeOp) {
          if (*InRangeOp == 0)
            return error(ID.Loc,
                         "inrange keyword may not appear on pointer operand");
          --*InRangeOp;
        }
  
        ID.ConstantVal = ConstantExpr::getGetElementPtr(Ty, Elts[0], Indices,
                                                        InBounds, InRangeOp);
      } else if (Opc == Instruction::Select) {
        if (Elts.size() != 3)
          return error(ID.Loc, "expected three operands to select");
        if (const char *Reason = SelectInst::areInvalidOperands(Elts[0], Elts[1],
                                                                Elts[2]))
          return error(ID.Loc, Reason);
        ID.ConstantVal = ConstantExpr::getSelect(Elts[0], Elts[1], Elts[2]);
      } else if (Opc == Instruction::ShuffleVector) {
        if (Elts.size() != 3)
          return error(ID.Loc, "expected three operands to shufflevector");
        if (!ShuffleVectorInst::isValidOperands(Elts[0], Elts[1], Elts[2]))
          return error(ID.Loc, "invalid operands to shufflevector");
        SmallVector<int, 16> Mask;
        ShuffleVectorInst::getShuffleMask(cast<Constant>(Elts[2]), Mask);
        ID.ConstantVal = ConstantExpr::getShuffleVector(Elts[0], Elts[1], Mask);
      } else if (Opc == Instruction::ExtractElement) {
        if (Elts.size() != 2)
          return error(ID.Loc, "expected two operands to extractelement");
        if (!ExtractElementInst::isValidOperands(Elts[0], Elts[1]))
          return error(ID.Loc, "invalid extractelement operands");
        ID.ConstantVal = ConstantExpr::getExtractElement(Elts[0], Elts[1]);
      } else {
        assert(Opc == Instruction::InsertElement && "Unknown opcode");
        if (Elts.size() != 3)
          return error(ID.Loc, "expected three operands to insertelement");
        if (!InsertElementInst::isValidOperands(Elts[0], Elts[1], Elts[2]))
          return error(ID.Loc, "invalid insertelement operands");
        ID.ConstantVal =
                   ConstantExpr::getInsertElement(Elts[0], Elts[1],Elts[2]);
      }
  
      ID.Kind = ValID::t_Constant;
      return false;
    }
    }
  
    Lex.Lex();
    return false;
  }
  
  /// parseGlobalValue - parse a global value with the specified type.
  bool LLParser::parseGlobalValue(Type *Ty, Constant *&C) {
    C = nullptr;
    ValID ID;
    Value *V = nullptr;
    bool Parsed = parseValID(ID, /*PFS=*/nullptr, Ty) ||
                  convertValIDToValue(Ty, ID, V, nullptr);
    if (V && !(C = dyn_cast<Constant>(V)))
      return error(ID.Loc, "global values must be constants");
    return Parsed;
  }
  
  bool LLParser::parseGlobalTypeAndValue(Constant *&V) {
    Type *Ty = nullptr;
    return parseType(Ty) || parseGlobalValue(Ty, V);
  }
  
  bool LLParser::parseOptionalComdat(StringRef GlobalName, Comdat *&C) {
    C = nullptr;
  
    LocTy KwLoc = Lex.getLoc();
    if (!EatIfPresent(lltok::kw_comdat))
      return false;
  
    if (EatIfPresent(lltok::lparen)) {
      if (Lex.getKind() != lltok::ComdatVar)
        return tokError("expected comdat variable");
      C = getComdat(Lex.getStrVal(), Lex.getLoc());
      Lex.Lex();
      if (parseToken(lltok::rparen, "expected ')' after comdat var"))
        return true;
    } else {
      if (GlobalName.empty())
        return tokError("comdat cannot be unnamed");
      C = getComdat(std::string(GlobalName), KwLoc);
    }
  
    return false;
  }
  
  /// parseGlobalValueVector
  ///   ::= /*empty*/
  ///   ::= [inrange] TypeAndValue (',' [inrange] TypeAndValue)*
  bool LLParser::parseGlobalValueVector(SmallVectorImpl<Constant *> &Elts,
                                        Optional<unsigned> *InRangeOp) {
    // Empty list.
    if (Lex.getKind() == lltok::rbrace ||
        Lex.getKind() == lltok::rsquare ||
        Lex.getKind() == lltok::greater ||
        Lex.getKind() == lltok::rparen)
      return false;
  
    do {
      if (InRangeOp && !*InRangeOp && EatIfPresent(lltok::kw_inrange))
        *InRangeOp = Elts.size();
  
      Constant *C;
      if (parseGlobalTypeAndValue(C))
        return true;
      Elts.push_back(C);
    } while (EatIfPresent(lltok::comma));
  
    return false;
  }
  
  bool LLParser::parseMDTuple(MDNode *&MD, bool IsDistinct) {
    SmallVector<Metadata *, 16> Elts;
    if (parseMDNodeVector(Elts))
      return true;
  
    MD = (IsDistinct ? MDTuple::getDistinct : MDTuple::get)(Context, Elts);
    return false;
  }
  
  /// MDNode:
  ///  ::= !{ ... }
  ///  ::= !7
  ///  ::= !DILocation(...)
  bool LLParser::parseMDNode(MDNode *&N) {
    if (Lex.getKind() == lltok::MetadataVar)
      return parseSpecializedMDNode(N);
  
    return parseToken(lltok::exclaim, "expected '!' here") || parseMDNodeTail(N);
  }
  
  bool LLParser::parseMDNodeTail(MDNode *&N) {
    // !{ ... }
    if (Lex.getKind() == lltok::lbrace)
      return parseMDTuple(N);
  
    // !42
    return parseMDNodeID(N);
  }
  
  namespace {
  
  /// Structure to represent an optional metadata field.
  template <class FieldTy> struct MDFieldImpl {
    typedef MDFieldImpl ImplTy;
    FieldTy Val;
    bool Seen;
  
    void assign(FieldTy Val) {
      Seen = true;
      this->Val = std::move(Val);
    }
  
    explicit MDFieldImpl(FieldTy Default)
        : Val(std::move(Default)), Seen(false) {}
  };
  
  /// Structure to represent an optional metadata field that
  /// can be of either type (A or B) and encapsulates the
  /// MD<typeofA>Field and MD<typeofB>Field structs, so not
  /// to reimplement the specifics for representing each Field.
  template <class FieldTypeA, class FieldTypeB> struct MDEitherFieldImpl {
    typedef MDEitherFieldImpl<FieldTypeA, FieldTypeB> ImplTy;
    FieldTypeA A;
    FieldTypeB B;
    bool Seen;
  
    enum {
      IsInvalid = 0,
      IsTypeA = 1,
      IsTypeB = 2
    } WhatIs;
  
    void assign(FieldTypeA A) {
      Seen = true;
      this->A = std::move(A);
      WhatIs = IsTypeA;
    }
  
    void assign(FieldTypeB B) {
      Seen = true;
      this->B = std::move(B);
      WhatIs = IsTypeB;
    }
  
    explicit MDEitherFieldImpl(FieldTypeA DefaultA, FieldTypeB DefaultB)
        : A(std::move(DefaultA)), B(std::move(DefaultB)), Seen(false),
          WhatIs(IsInvalid) {}
  };
  
  struct MDUnsignedField : public MDFieldImpl<uint64_t> {
    uint64_t Max;
  
    MDUnsignedField(uint64_t Default = 0, uint64_t Max = UINT64_MAX)
        : ImplTy(Default), Max(Max) {}
  };
  
  struct LineField : public MDUnsignedField {
    LineField() : MDUnsignedField(0, UINT32_MAX) {}
  };
  
  struct ColumnField : public MDUnsignedField {
    ColumnField() : MDUnsignedField(0, UINT16_MAX) {}
  };
  
  struct DwarfTagField : public MDUnsignedField {
    DwarfTagField() : MDUnsignedField(0, dwarf::DW_TAG_hi_user) {}
    DwarfTagField(dwarf::Tag DefaultTag)
        : MDUnsignedField(DefaultTag, dwarf::DW_TAG_hi_user) {}
  };
  
  struct DwarfMacinfoTypeField : public MDUnsignedField {
    DwarfMacinfoTypeField() : MDUnsignedField(0, dwarf::DW_MACINFO_vendor_ext) {}
    DwarfMacinfoTypeField(dwarf::MacinfoRecordType DefaultType)
      : MDUnsignedField(DefaultType, dwarf::DW_MACINFO_vendor_ext) {}
  };
  
  struct DwarfAttEncodingField : public MDUnsignedField {
    DwarfAttEncodingField() : MDUnsignedField(0, dwarf::DW_ATE_hi_user) {}
  };
  
  struct DwarfVirtualityField : public MDUnsignedField {
    DwarfVirtualityField() : MDUnsignedField(0, dwarf::DW_VIRTUALITY_max) {}
  };
  
  struct DwarfLangField : public MDUnsignedField {
    DwarfLangField() : MDUnsignedField(0, dwarf::DW_LANG_hi_user) {}
  };
  
  struct DwarfCCField : public MDUnsignedField {
    DwarfCCField() : MDUnsignedField(0, dwarf::DW_CC_hi_user) {}
  };
  
  struct EmissionKindField : public MDUnsignedField {
    EmissionKindField() : MDUnsignedField(0, DICompileUnit::LastEmissionKind) {}
  };
  
  struct NameTableKindField : public MDUnsignedField {
    NameTableKindField()
        : MDUnsignedField(
              0, (unsigned)
                     DICompileUnit::DebugNameTableKind::LastDebugNameTableKind) {}
  };
  
  struct DIFlagField : public MDFieldImpl<DINode::DIFlags> {
    DIFlagField() : MDFieldImpl(DINode::FlagZero) {}
  };
  
  struct DISPFlagField : public MDFieldImpl<DISubprogram::DISPFlags> {
    DISPFlagField() : MDFieldImpl(DISubprogram::SPFlagZero) {}
  };
  
  struct MDAPSIntField : public MDFieldImpl<APSInt> {
    MDAPSIntField() : ImplTy(APSInt()) {}
  };
  
  struct MDSignedField : public MDFieldImpl<int64_t> {
    int64_t Min;
    int64_t Max;
  
    MDSignedField(int64_t Default = 0)
        : ImplTy(Default), Min(INT64_MIN), Max(INT64_MAX) {}
    MDSignedField(int64_t Default, int64_t Min, int64_t Max)
        : ImplTy(Default), Min(Min), Max(Max) {}
  };
  
  struct MDBoolField : public MDFieldImpl<bool> {
    MDBoolField(bool Default = false) : ImplTy(Default) {}
  };
  
  struct MDField : public MDFieldImpl<Metadata *> {
    bool AllowNull;
  
    MDField(bool AllowNull = true) : ImplTy(nullptr), AllowNull(AllowNull) {}
  };
  
  struct MDStringField : public MDFieldImpl<MDString *> {
    bool AllowEmpty;
    MDStringField(bool AllowEmpty = true)
        : ImplTy(nullptr), AllowEmpty(AllowEmpty) {}
  };
  
  struct MDFieldList : public MDFieldImpl<SmallVector<Metadata *, 4>> {
    MDFieldList() : ImplTy(SmallVector<Metadata *, 4>()) {}
  };
  
  struct ChecksumKindField : public MDFieldImpl<DIFile::ChecksumKind> {
    ChecksumKindField(DIFile::ChecksumKind CSKind) : ImplTy(CSKind) {}
  };
  
  struct MDSignedOrMDField : MDEitherFieldImpl<MDSignedField, MDField> {
    MDSignedOrMDField(int64_t Default = 0, bool AllowNull = true)
        : ImplTy(MDSignedField(Default), MDField(AllowNull)) {}
  
    MDSignedOrMDField(int64_t Default, int64_t Min, int64_t Max,
                      bool AllowNull = true)
        : ImplTy(MDSignedField(Default, Min, Max), MDField(AllowNull)) {}
  
    bool isMDSignedField() const { return WhatIs == IsTypeA; }
    bool isMDField() const { return WhatIs == IsTypeB; }
    int64_t getMDSignedValue() const {
      assert(isMDSignedField() && "Wrong field type");
      return A.Val;
    }
    Metadata *getMDFieldValue() const {
      assert(isMDField() && "Wrong field type");
      return B.Val;
    }
  };
  
  } // end anonymous namespace
  
  namespace llvm {
  
  template <>
  bool LLParser::parseMDField(LocTy Loc, StringRef Name, MDAPSIntField &Result) {
    if (Lex.getKind() != lltok::APSInt)
      return tokError("expected integer");
  
    Result.assign(Lex.getAPSIntVal());
    Lex.Lex();
    return false;
  }
  
  template <>
  bool LLParser::parseMDField(LocTy Loc, StringRef Name,
                              MDUnsignedField &Result) {
    if (Lex.getKind() != lltok::APSInt || Lex.getAPSIntVal().isSigned())
      return tokError("expected unsigned integer");
  
    auto &U = Lex.getAPSIntVal();
    if (U.ugt(Result.Max))
      return tokError("value for '" + Name + "' too large, limit is " +
                      Twine(Result.Max));
    Result.assign(U.getZExtValue());
    assert(Result.Val <= Result.Max && "Expected value in range");
    Lex.Lex();
    return false;
  }
  
  template <>
  bool LLParser::parseMDField(LocTy Loc, StringRef Name, LineField &Result) {
    return parseMDField(Loc, Name, static_cast<MDUnsignedField &>(Result));
  }
  template <>
  bool LLParser::parseMDField(LocTy Loc, StringRef Name, ColumnField &Result) {
    return parseMDField(Loc, Name, static_cast<MDUnsignedField &>(Result));
  }
  
  template <>
  bool LLParser::parseMDField(LocTy Loc, StringRef Name, DwarfTagField &Result) {
    if (Lex.getKind() == lltok::APSInt)
      return parseMDField(Loc, Name, static_cast<MDUnsignedField &>(Result));
  
    if (Lex.getKind() != lltok::DwarfTag)
      return tokError("expected DWARF tag");
  
    unsigned Tag = dwarf::getTag(Lex.getStrVal());
    if (Tag == dwarf::DW_TAG_invalid)
      return tokError("invalid DWARF tag" + Twine(" '") + Lex.getStrVal() + "'");
    assert(Tag <= Result.Max && "Expected valid DWARF tag");
  
    Result.assign(Tag);
    Lex.Lex();
    return false;
  }
  
  template <>
  bool LLParser::parseMDField(LocTy Loc, StringRef Name,
                              DwarfMacinfoTypeField &Result) {
    if (Lex.getKind() == lltok::APSInt)
      return parseMDField(Loc, Name, static_cast<MDUnsignedField &>(Result));
  
    if (Lex.getKind() != lltok::DwarfMacinfo)
      return tokError("expected DWARF macinfo type");
  
    unsigned Macinfo = dwarf::getMacinfo(Lex.getStrVal());
    if (Macinfo == dwarf::DW_MACINFO_invalid)
      return tokError("invalid DWARF macinfo type" + Twine(" '") +
                      Lex.getStrVal() + "'");
    assert(Macinfo <= Result.Max && "Expected valid DWARF macinfo type");
  
    Result.assign(Macinfo);
    Lex.Lex();
    return false;
  }
  
  template <>
  bool LLParser::parseMDField(LocTy Loc, StringRef Name,
                              DwarfVirtualityField &Result) {
    if (Lex.getKind() == lltok::APSInt)
      return parseMDField(Loc, Name, static_cast<MDUnsignedField &>(Result));
  
    if (Lex.getKind() != lltok::DwarfVirtuality)
      return tokError("expected DWARF virtuality code");
  
    unsigned Virtuality = dwarf::getVirtuality(Lex.getStrVal());
    if (Virtuality == dwarf::DW_VIRTUALITY_invalid)
      return tokError("invalid DWARF virtuality code" + Twine(" '") +
                      Lex.getStrVal() + "'");
    assert(Virtuality <= Result.Max && "Expected valid DWARF virtuality code");
    Result.assign(Virtuality);
    Lex.Lex();
    return false;
  }
  
  template <>
  bool LLParser::parseMDField(LocTy Loc, StringRef Name, DwarfLangField &Result) {
    if (Lex.getKind() == lltok::APSInt)
      return parseMDField(Loc, Name, static_cast<MDUnsignedField &>(Result));
  
    if (Lex.getKind() != lltok::DwarfLang)
      return tokError("expected DWARF language");
  
    unsigned Lang = dwarf::getLanguage(Lex.getStrVal());
    if (!Lang)
      return tokError("invalid DWARF language" + Twine(" '") + Lex.getStrVal() +
                      "'");
    assert(Lang <= Result.Max && "Expected valid DWARF language");
    Result.assign(Lang);
    Lex.Lex();
    return false;
  }
  
  template <>
  bool LLParser::parseMDField(LocTy Loc, StringRef Name, DwarfCCField &Result) {
    if (Lex.getKind() == lltok::APSInt)
      return parseMDField(Loc, Name, static_cast<MDUnsignedField &>(Result));
  
    if (Lex.getKind() != lltok::DwarfCC)
      return tokError("expected DWARF calling convention");
  
    unsigned CC = dwarf::getCallingConvention(Lex.getStrVal());
    if (!CC)
      return tokError("invalid DWARF calling convention" + Twine(" '") +
                      Lex.getStrVal() + "'");
    assert(CC <= Result.Max && "Expected valid DWARF calling convention");
    Result.assign(CC);
    Lex.Lex();
    return false;
  }
  
  template <>
  bool LLParser::parseMDField(LocTy Loc, StringRef Name,
                              EmissionKindField &Result) {
    if (Lex.getKind() == lltok::APSInt)
      return parseMDField(Loc, Name, static_cast<MDUnsignedField &>(Result));
  
    if (Lex.getKind() != lltok::EmissionKind)
      return tokError("expected emission kind");
  
    auto Kind = DICompileUnit::getEmissionKind(Lex.getStrVal());
    if (!Kind)
      return tokError("invalid emission kind" + Twine(" '") + Lex.getStrVal() +
                      "'");
    assert(*Kind <= Result.Max && "Expected valid emission kind");
    Result.assign(*Kind);
    Lex.Lex();
    return false;
  }
  
  template <>
  bool LLParser::parseMDField(LocTy Loc, StringRef Name,
                              NameTableKindField &Result) {
    if (Lex.getKind() == lltok::APSInt)
      return parseMDField(Loc, Name, static_cast<MDUnsignedField &>(Result));
  
    if (Lex.getKind() != lltok::NameTableKind)
      return tokError("expected nameTable kind");
  
    auto Kind = DICompileUnit::getNameTableKind(Lex.getStrVal());
    if (!Kind)
      return tokError("invalid nameTable kind" + Twine(" '") + Lex.getStrVal() +
                      "'");
    assert(((unsigned)*Kind) <= Result.Max && "Expected valid nameTable kind");
    Result.assign((unsigned)*Kind);
    Lex.Lex();
    return false;
  }
  
  template <>
  bool LLParser::parseMDField(LocTy Loc, StringRef Name,
                              DwarfAttEncodingField &Result) {
    if (Lex.getKind() == lltok::APSInt)
      return parseMDField(Loc, Name, static_cast<MDUnsignedField &>(Result));
  
    if (Lex.getKind() != lltok::DwarfAttEncoding)
      return tokError("expected DWARF type attribute encoding");
  
    unsigned Encoding = dwarf::getAttributeEncoding(Lex.getStrVal());
    if (!Encoding)
      return tokError("invalid DWARF type attribute encoding" + Twine(" '") +
                      Lex.getStrVal() + "'");
    assert(Encoding <= Result.Max && "Expected valid DWARF language");
    Result.assign(Encoding);
    Lex.Lex();
    return false;
  }
  
  /// DIFlagField
  ///  ::= uint32
  ///  ::= DIFlagVector
  ///  ::= DIFlagVector '|' DIFlagFwdDecl '|' uint32 '|' DIFlagPublic
  template <>
  bool LLParser::parseMDField(LocTy Loc, StringRef Name, DIFlagField &Result) {
  
    // parser for a single flag.
    auto parseFlag = [&](DINode::DIFlags &Val) {
      if (Lex.getKind() == lltok::APSInt && !Lex.getAPSIntVal().isSigned()) {
        uint32_t TempVal = static_cast<uint32_t>(Val);
        bool Res = parseUInt32(TempVal);
        Val = static_cast<DINode::DIFlags>(TempVal);
        return Res;
      }
  
      if (Lex.getKind() != lltok::DIFlag)
        return tokError("expected debug info flag");
  
      Val = DINode::getFlag(Lex.getStrVal());
      if (!Val)
        return tokError(Twine("invalid debug info flag flag '") +
                        Lex.getStrVal() + "'");
      Lex.Lex();
      return false;
    };
  
    // parse the flags and combine them together.
    DINode::DIFlags Combined = DINode::FlagZero;
    do {
      DINode::DIFlags Val;
      if (parseFlag(Val))
        return true;
      Combined |= Val;
    } while (EatIfPresent(lltok::bar));
  
    Result.assign(Combined);
    return false;
  }
  
  /// DISPFlagField
  ///  ::= uint32
  ///  ::= DISPFlagVector
  ///  ::= DISPFlagVector '|' DISPFlag* '|' uint32
  template <>
  bool LLParser::parseMDField(LocTy Loc, StringRef Name, DISPFlagField &Result) {
  
    // parser for a single flag.
    auto parseFlag = [&](DISubprogram::DISPFlags &Val) {
      if (Lex.getKind() == lltok::APSInt && !Lex.getAPSIntVal().isSigned()) {
        uint32_t TempVal = static_cast<uint32_t>(Val);
        bool Res = parseUInt32(TempVal);
        Val = static_cast<DISubprogram::DISPFlags>(TempVal);
        return Res;
      }
  
      if (Lex.getKind() != lltok::DISPFlag)
        return tokError("expected debug info flag");
  
      Val = DISubprogram::getFlag(Lex.getStrVal());
      if (!Val)
        return tokError(Twine("invalid subprogram debug info flag '") +
                        Lex.getStrVal() + "'");
      Lex.Lex();
      return false;
    };
  
    // parse the flags and combine them together.
    DISubprogram::DISPFlags Combined = DISubprogram::SPFlagZero;
    do {
      DISubprogram::DISPFlags Val;
      if (parseFlag(Val))
        return true;
      Combined |= Val;
    } while (EatIfPresent(lltok::bar));
  
    Result.assign(Combined);
    return false;
  }
  
  template <>
  bool LLParser::parseMDField(LocTy Loc, StringRef Name, MDSignedField &Result) {
    if (Lex.getKind() != lltok::APSInt)
      return tokError("expected signed integer");
  
    auto &S = Lex.getAPSIntVal();
    if (S < Result.Min)
      return tokError("value for '" + Name + "' too small, limit is " +
                      Twine(Result.Min));
    if (S > Result.Max)
      return tokError("value for '" + Name + "' too large, limit is " +
                      Twine(Result.Max));
    Result.assign(S.getExtValue());
    assert(Result.Val >= Result.Min && "Expected value in range");
    assert(Result.Val <= Result.Max && "Expected value in range");
    Lex.Lex();
    return false;
  }
  
  template <>
  bool LLParser::parseMDField(LocTy Loc, StringRef Name, MDBoolField &Result) {
    switch (Lex.getKind()) {
    default:
      return tokError("expected 'true' or 'false'");
    case lltok::kw_true:
      Result.assign(true);
      break;
    case lltok::kw_false:
      Result.assign(false);
      break;
    }
    Lex.Lex();
    return false;
  }
  
  template <>
  bool LLParser::parseMDField(LocTy Loc, StringRef Name, MDField &Result) {
    if (Lex.getKind() == lltok::kw_null) {
      if (!Result.AllowNull)
        return tokError("'" + Name + "' cannot be null");
      Lex.Lex();
      Result.assign(nullptr);
      return false;
    }
  
    Metadata *MD;
    if (parseMetadata(MD, nullptr))
      return true;
  
    Result.assign(MD);
    return false;
  }
  
  template <>
  bool LLParser::parseMDField(LocTy Loc, StringRef Name,
                              MDSignedOrMDField &Result) {
    // Try to parse a signed int.
    if (Lex.getKind() == lltok::APSInt) {
      MDSignedField Res = Result.A;
      if (!parseMDField(Loc, Name, Res)) {
        Result.assign(Res);
        return false;
      }
      return true;
    }
  
    // Otherwise, try to parse as an MDField.
    MDField Res = Result.B;
    if (!parseMDField(Loc, Name, Res)) {
      Result.assign(Res);
      return false;
    }
  
    return true;
  }
  
  template <>
  bool LLParser::parseMDField(LocTy Loc, StringRef Name, MDStringField &Result) {
    LocTy ValueLoc = Lex.getLoc();
    std::string S;
    if (parseStringConstant(S))
      return true;
  
    if (!Result.AllowEmpty && S.empty())
      return error(ValueLoc, "'" + Name + "' cannot be empty");
  
    Result.assign(S.empty() ? nullptr : MDString::get(Context, S));
    return false;
  }
  
  template <>
  bool LLParser::parseMDField(LocTy Loc, StringRef Name, MDFieldList &Result) {
    SmallVector<Metadata *, 4> MDs;
    if (parseMDNodeVector(MDs))
      return true;
  
    Result.assign(std::move(MDs));
    return false;
  }
  
  template <>
  bool LLParser::parseMDField(LocTy Loc, StringRef Name,
                              ChecksumKindField &Result) {
    Optional<DIFile::ChecksumKind> CSKind =
        DIFile::getChecksumKind(Lex.getStrVal());
  
    if (Lex.getKind() != lltok::ChecksumKind || !CSKind)
      return tokError("invalid checksum kind" + Twine(" '") + Lex.getStrVal() +
                      "'");
  
    Result.assign(*CSKind);
    Lex.Lex();
    return false;
  }
  
  } // end namespace llvm
  
  template <class ParserTy>
  bool LLParser::parseMDFieldsImplBody(ParserTy ParseField) {
    do {
      if (Lex.getKind() != lltok::LabelStr)
        return tokError("expected field label here");
  
      if (ParseField())
        return true;
    } while (EatIfPresent(lltok::comma));
  
    return false;
  }
  
  template <class ParserTy>
  bool LLParser::parseMDFieldsImpl(ParserTy ParseField, LocTy &ClosingLoc) {
    assert(Lex.getKind() == lltok::MetadataVar && "Expected metadata type name");
    Lex.Lex();
  
    if (parseToken(lltok::lparen, "expected '(' here"))
      return true;
    if (Lex.getKind() != lltok::rparen)
      if (parseMDFieldsImplBody(ParseField))
        return true;
  
    ClosingLoc = Lex.getLoc();
    return parseToken(lltok::rparen, "expected ')' here");
  }
  
  template <class FieldTy>
  bool LLParser::parseMDField(StringRef Name, FieldTy &Result) {
    if (Result.Seen)
      return tokError("field '" + Name + "' cannot be specified more than once");
  
    LocTy Loc = Lex.getLoc();
    Lex.Lex();
    return parseMDField(Loc, Name, Result);
  }
  
  bool LLParser::parseSpecializedMDNode(MDNode *&N, bool IsDistinct) {
    assert(Lex.getKind() == lltok::MetadataVar && "Expected metadata type name");
  
  #define HANDLE_SPECIALIZED_MDNODE_LEAF(CLASS)                                  \
    if (Lex.getStrVal() == #CLASS)                                               \
      return parse##CLASS(N, IsDistinct);
  #include "llvm/IR/Metadata.def"
  
    return tokError("expected metadata type");
  }
  
  #define DECLARE_FIELD(NAME, TYPE, INIT) TYPE NAME INIT
  #define NOP_FIELD(NAME, TYPE, INIT)
  #define REQUIRE_FIELD(NAME, TYPE, INIT)                                        \
    if (!NAME.Seen)                                                              \
      return error(ClosingLoc, "missing required field '" #NAME "'");
  #define PARSE_MD_FIELD(NAME, TYPE, DEFAULT)                                    \
    if (Lex.getStrVal() == #NAME)                                                \
      return parseMDField(#NAME, NAME);
  #define PARSE_MD_FIELDS()                                                      \
    VISIT_MD_FIELDS(DECLARE_FIELD, DECLARE_FIELD)                                \
    do {                                                                         \
      LocTy ClosingLoc;                                                          \
      if (parseMDFieldsImpl(                                                     \
              [&]() -> bool {                                                    \
                VISIT_MD_FIELDS(PARSE_MD_FIELD, PARSE_MD_FIELD)                  \
                return tokError(Twine("invalid field '") + Lex.getStrVal() +     \
                                "'");                                            \
              },                                                                 \
              ClosingLoc))                                                       \
        return true;                                                             \
      VISIT_MD_FIELDS(NOP_FIELD, REQUIRE_FIELD)                                  \
    } while (false)
  #define GET_OR_DISTINCT(CLASS, ARGS)                                           \
    (IsDistinct ? CLASS::getDistinct ARGS : CLASS::get ARGS)
  
  /// parseDILocationFields:
  ///   ::= !DILocation(line: 43, column: 8, scope: !5, inlinedAt: !6,
  ///   isImplicitCode: true)
  bool LLParser::parseDILocation(MDNode *&Result, bool IsDistinct) {
  #define VISIT_MD_FIELDS(OPTIONAL, REQUIRED)                                    \
    OPTIONAL(line, LineField, );                                                 \
    OPTIONAL(column, ColumnField, );                                             \
    REQUIRED(scope, MDField, (/* AllowNull */ false));                           \
    OPTIONAL(inlinedAt, MDField, );                                              \
    OPTIONAL(isImplicitCode, MDBoolField, (false));
    PARSE_MD_FIELDS();
  #undef VISIT_MD_FIELDS
  
    Result =
        GET_OR_DISTINCT(DILocation, (Context, line.Val, column.Val, scope.Val,
                                     inlinedAt.Val, isImplicitCode.Val));
    return false;
  }
  
  /// parseGenericDINode:
  ///   ::= !GenericDINode(tag: 15, header: "...", operands: {...})
  bool LLParser::parseGenericDINode(MDNode *&Result, bool IsDistinct) {
  #define VISIT_MD_FIELDS(OPTIONAL, REQUIRED)                                    \
    REQUIRED(tag, DwarfTagField, );                                              \
    OPTIONAL(header, MDStringField, );                                           \
    OPTIONAL(operands, MDFieldList, );
    PARSE_MD_FIELDS();
  #undef VISIT_MD_FIELDS
  
    Result = GET_OR_DISTINCT(GenericDINode,
                             (Context, tag.Val, header.Val, operands.Val));
    return false;
  }
  
  /// parseDISubrange:
  ///   ::= !DISubrange(count: 30, lowerBound: 2)
  ///   ::= !DISubrange(count: !node, lowerBound: 2)
  ///   ::= !DISubrange(lowerBound: !node1, upperBound: !node2, stride: !node3)
  bool LLParser::parseDISubrange(MDNode *&Result, bool IsDistinct) {
  #define VISIT_MD_FIELDS(OPTIONAL, REQUIRED)                                    \
    OPTIONAL(count, MDSignedOrMDField, (-1, -1, INT64_MAX, false));              \
    OPTIONAL(lowerBound, MDSignedOrMDField, );                                   \
    OPTIONAL(upperBound, MDSignedOrMDField, );                                   \
    OPTIONAL(stride, MDSignedOrMDField, );
    PARSE_MD_FIELDS();
  #undef VISIT_MD_FIELDS
  
    Metadata *Count = nullptr;
    Metadata *LowerBound = nullptr;
    Metadata *UpperBound = nullptr;
    Metadata *Stride = nullptr;
  
    auto convToMetadata = [&](MDSignedOrMDField Bound) -> Metadata * {
      if (Bound.isMDSignedField())
        return ConstantAsMetadata::get(ConstantInt::getSigned(
            Type::getInt64Ty(Context), Bound.getMDSignedValue()));
      if (Bound.isMDField())
        return Bound.getMDFieldValue();
      return nullptr;
    };
  
    Count = convToMetadata(count);
    LowerBound = convToMetadata(lowerBound);
    UpperBound = convToMetadata(upperBound);
    Stride = convToMetadata(stride);
  
    Result = GET_OR_DISTINCT(DISubrange,
                             (Context, Count, LowerBound, UpperBound, Stride));
  
    return false;
  }
  
  /// parseDIGenericSubrange:
  ///   ::= !DIGenericSubrange(lowerBound: !node1, upperBound: !node2, stride:
  ///   !node3)
  bool LLParser::parseDIGenericSubrange(MDNode *&Result, bool IsDistinct) {
  #define VISIT_MD_FIELDS(OPTIONAL, REQUIRED)                                    \
    OPTIONAL(count, MDSignedOrMDField, );                                        \
    OPTIONAL(lowerBound, MDSignedOrMDField, );                                   \
    OPTIONAL(upperBound, MDSignedOrMDField, );                                   \
    OPTIONAL(stride, MDSignedOrMDField, );
    PARSE_MD_FIELDS();
  #undef VISIT_MD_FIELDS
  
    auto ConvToMetadata = [&](MDSignedOrMDField Bound) -> Metadata * {
      if (Bound.isMDSignedField())
        return DIExpression::get(
            Context, {dwarf::DW_OP_consts,
                      static_cast<uint64_t>(Bound.getMDSignedValue())});
      if (Bound.isMDField())
        return Bound.getMDFieldValue();
      return nullptr;
    };
  
    Metadata *Count = ConvToMetadata(count);
    Metadata *LowerBound = ConvToMetadata(lowerBound);
    Metadata *UpperBound = ConvToMetadata(upperBound);
    Metadata *Stride = ConvToMetadata(stride);
  
    Result = GET_OR_DISTINCT(DIGenericSubrange,
                             (Context, Count, LowerBound, UpperBound, Stride));
  
    return false;
  }
  
  /// parseDIEnumerator:
  ///   ::= !DIEnumerator(value: 30, isUnsigned: true, name: "SomeKind")
  bool LLParser::parseDIEnumerator(MDNode *&Result, bool IsDistinct) {
  #define VISIT_MD_FIELDS(OPTIONAL, REQUIRED)                                    \
    REQUIRED(name, MDStringField, );                                             \
    REQUIRED(value, MDAPSIntField, );                                            \
    OPTIONAL(isUnsigned, MDBoolField, (false));
    PARSE_MD_FIELDS();
  #undef VISIT_MD_FIELDS
  
    if (isUnsigned.Val && value.Val.isNegative())
      return tokError("unsigned enumerator with negative value");
  
    APSInt Value(value.Val);
    // Add a leading zero so that unsigned values with the msb set are not
    // mistaken for negative values when used for signed enumerators.
    if (!isUnsigned.Val && value.Val.isUnsigned() && value.Val.isSignBitSet())
      Value = Value.zext(Value.getBitWidth() + 1);
  
    Result =
        GET_OR_DISTINCT(DIEnumerator, (Context, Value, isUnsigned.Val, name.Val));
  
    return false;
  }
  
  /// parseDIBasicType:
  ///   ::= !DIBasicType(tag: DW_TAG_base_type, name: "int", size: 32, align: 32,
  ///                    encoding: DW_ATE_encoding, flags: 0)
  bool LLParser::parseDIBasicType(MDNode *&Result, bool IsDistinct) {
  #define VISIT_MD_FIELDS(OPTIONAL, REQUIRED)                                    \
    OPTIONAL(tag, DwarfTagField, (dwarf::DW_TAG_base_type));                     \
    OPTIONAL(name, MDStringField, );                                             \
    OPTIONAL(size, MDUnsignedField, (0, UINT64_MAX));                            \
    OPTIONAL(align, MDUnsignedField, (0, UINT32_MAX));                           \
    OPTIONAL(encoding, DwarfAttEncodingField, );                                 \
    OPTIONAL(flags, DIFlagField, );
    PARSE_MD_FIELDS();
  #undef VISIT_MD_FIELDS
  
    Result = GET_OR_DISTINCT(DIBasicType, (Context, tag.Val, name.Val, size.Val,
                                           align.Val, encoding.Val, flags.Val));
    return false;
  }
  
  /// parseDIStringType:
  ///   ::= !DIStringType(name: "character(4)", size: 32, align: 32)
  bool LLParser::parseDIStringType(MDNode *&Result, bool IsDistinct) {
  #define VISIT_MD_FIELDS(OPTIONAL, REQUIRED)                                    \
    OPTIONAL(tag, DwarfTagField, (dwarf::DW_TAG_string_type));                   \
    OPTIONAL(name, MDStringField, );                                             \
    OPTIONAL(stringLength, MDField, );                                           \
    OPTIONAL(stringLengthExpression, MDField, );                                 \
    OPTIONAL(size, MDUnsignedField, (0, UINT64_MAX));                            \
    OPTIONAL(align, MDUnsignedField, (0, UINT32_MAX));                           \
    OPTIONAL(encoding, DwarfAttEncodingField, );
    PARSE_MD_FIELDS();
  #undef VISIT_MD_FIELDS
  
    Result = GET_OR_DISTINCT(DIStringType,
                             (Context, tag.Val, name.Val, stringLength.Val,
                              stringLengthExpression.Val, size.Val, align.Val,
                              encoding.Val));
    return false;
  }
  
  /// parseDIDerivedType:
  ///   ::= !DIDerivedType(tag: DW_TAG_pointer_type, name: "int", file: !0,
  ///                      line: 7, scope: !1, baseType: !2, size: 32,
  ///                      align: 32, offset: 0, flags: 0, extraData: !3,
  ///                      dwarfAddressSpace: 3, ptrAuthKey: 1,
  ///                      ptrAuthIsAddressDiscriminated: true,
  ///                      ptrAuthExtraDiscriminator: 0x1234)
  bool LLParser::parseDIDerivedType(MDNode *&Result, bool IsDistinct) {
  #define VISIT_MD_FIELDS(OPTIONAL, REQUIRED)                                    \
    REQUIRED(tag, DwarfTagField, );                                              \
    OPTIONAL(name, MDStringField, );                                             \
    OPTIONAL(file, MDField, );                                                   \
    OPTIONAL(line, LineField, );                                                 \
    OPTIONAL(scope, MDField, );                                                  \
    REQUIRED(baseType, MDField, );                                               \
    OPTIONAL(size, MDUnsignedField, (0, UINT64_MAX));                            \
    OPTIONAL(align, MDUnsignedField, (0, UINT32_MAX));                           \
    OPTIONAL(offset, MDUnsignedField, (0, UINT64_MAX));                          \
    OPTIONAL(flags, DIFlagField, );                                              \
    OPTIONAL(extraData, MDField, );                                              \
    OPTIONAL(dwarfAddressSpace, MDUnsignedField, (UINT32_MAX, UINT32_MAX));      \
    OPTIONAL(annotations, MDField, );                                            \
    OPTIONAL(ptrAuthKey, MDUnsignedField, (0, 7));                               \
    OPTIONAL(ptrAuthIsAddressDiscriminated, MDBoolField, );                      \
    OPTIONAL(ptrAuthExtraDiscriminator, MDUnsignedField, (0, 0xffff));
    PARSE_MD_FIELDS();
  #undef VISIT_MD_FIELDS
  
    Optional<unsigned> DWARFAddressSpace;
    if (dwarfAddressSpace.Val != UINT32_MAX)
      DWARFAddressSpace = dwarfAddressSpace.Val;
    Optional<DIDerivedType::PtrAuthData> PtrAuthData;
    if (ptrAuthKey.Val)
      PtrAuthData = DIDerivedType::PtrAuthData(
          (unsigned)ptrAuthKey.Val, ptrAuthIsAddressDiscriminated.Val,
          (unsigned)ptrAuthExtraDiscriminator.Val);
  
    Result = GET_OR_DISTINCT(DIDerivedType,
                             (Context, tag.Val, name.Val, file.Val, line.Val,
                              scope.Val, baseType.Val, size.Val, align.Val,
                              offset.Val, DWARFAddressSpace, PtrAuthData,
                              flags.Val, extraData.Val, annotations.Val));
    return false;
  }
  
  bool LLParser::parseDICompositeType(MDNode *&Result, bool IsDistinct) {
  #define VISIT_MD_FIELDS(OPTIONAL, REQUIRED)                                    \
    REQUIRED(tag, DwarfTagField, );                                              \
    OPTIONAL(name, MDStringField, );                                             \
    OPTIONAL(file, MDField, );                                                   \
    OPTIONAL(line, LineField, );                                                 \
    OPTIONAL(scope, MDField, );                                                  \
    OPTIONAL(baseType, MDField, );                                               \
    OPTIONAL(size, MDUnsignedField, (0, UINT64_MAX));                            \
    OPTIONAL(align, MDUnsignedField, (0, UINT32_MAX));                           \
    OPTIONAL(offset, MDUnsignedField, (0, UINT64_MAX));                          \
    OPTIONAL(flags, DIFlagField, );                                              \
    OPTIONAL(elements, MDField, );                                               \
    OPTIONAL(runtimeLang, DwarfLangField, );                                     \
    OPTIONAL(vtableHolder, MDField, );                                           \
    OPTIONAL(templateParams, MDField, );                                         \
    OPTIONAL(identifier, MDStringField, );                                       \
    OPTIONAL(discriminator, MDField, );                                          \
    OPTIONAL(dataLocation, MDField, );                                           \
    OPTIONAL(associated, MDField, );                                             \
    OPTIONAL(allocated, MDField, );                                              \
    OPTIONAL(rank, MDSignedOrMDField, );                                         \
    OPTIONAL(annotations, MDField, );
    PARSE_MD_FIELDS();
  #undef VISIT_MD_FIELDS
  
    Metadata *Rank = nullptr;
    if (rank.isMDSignedField())
      Rank = ConstantAsMetadata::get(ConstantInt::getSigned(
          Type::getInt64Ty(Context), rank.getMDSignedValue()));
    else if (rank.isMDField())
      Rank = rank.getMDFieldValue();
  
    // If this has an identifier try to build an ODR type.
    if (identifier.Val)
      if (auto *CT = DICompositeType::buildODRType(
              Context, *identifier.Val, tag.Val, name.Val, file.Val, line.Val,
              scope.Val, baseType.Val, size.Val, align.Val, offset.Val, flags.Val,
              elements.Val, runtimeLang.Val, vtableHolder.Val, templateParams.Val,
              discriminator.Val, dataLocation.Val, associated.Val, allocated.Val,
              Rank, annotations.Val)) {
        Result = CT;
        return false;
      }
  
    // Create a new node, and save it in the context if it belongs in the type
    // map.
    Result = GET_OR_DISTINCT(
        DICompositeType,
        (Context, tag.Val, name.Val, file.Val, line.Val, scope.Val, baseType.Val,
         size.Val, align.Val, offset.Val, flags.Val, elements.Val,
         runtimeLang.Val, vtableHolder.Val, templateParams.Val, identifier.Val,
         discriminator.Val, dataLocation.Val, associated.Val, allocated.Val, Rank,
         annotations.Val));
    return false;
  }
  
  bool LLParser::parseDISubroutineType(MDNode *&Result, bool IsDistinct) {
  #define VISIT_MD_FIELDS(OPTIONAL, REQUIRED)                                    \
    OPTIONAL(flags, DIFlagField, );                                              \
    OPTIONAL(cc, DwarfCCField, );                                                \
    REQUIRED(types, MDField, );
    PARSE_MD_FIELDS();
  #undef VISIT_MD_FIELDS
  
    Result = GET_OR_DISTINCT(DISubroutineType,
                             (Context, flags.Val, cc.Val, types.Val));
    return false;
  }
  
  /// parseDIFileType:
  ///   ::= !DIFileType(filename: "path/to/file", directory: "/path/to/dir",
  ///                   checksumkind: CSK_MD5,
  ///                   checksum: "000102030405060708090a0b0c0d0e0f",
  ///                   source: "source file contents")
  bool LLParser::parseDIFile(MDNode *&Result, bool IsDistinct) {
    // The default constructed value for checksumkind is required, but will never
    // be used, as the parser checks if the field was actually Seen before using
    // the Val.
  #define VISIT_MD_FIELDS(OPTIONAL, REQUIRED)                                    \
    REQUIRED(filename, MDStringField, );                                         \
    REQUIRED(directory, MDStringField, );                                        \
    OPTIONAL(checksumkind, ChecksumKindField, (DIFile::CSK_MD5));                \
    OPTIONAL(checksum, MDStringField, );                                         \
    OPTIONAL(source, MDStringField, );
    PARSE_MD_FIELDS();
  #undef VISIT_MD_FIELDS
  
    Optional<DIFile::ChecksumInfo<MDString *>> OptChecksum;
    if (checksumkind.Seen && checksum.Seen)
      OptChecksum.emplace(checksumkind.Val, checksum.Val);
    else if (checksumkind.Seen || checksum.Seen)
      return Lex.Error("'checksumkind' and 'checksum' must be provided together");
  
    Optional<MDString *> OptSource;
    if (source.Seen)
      OptSource = source.Val;
    Result = GET_OR_DISTINCT(DIFile, (Context, filename.Val, directory.Val,
                                      OptChecksum, OptSource));
    return false;
  }
  
  /// parseDICompileUnit:
  ///   ::= !DICompileUnit(language: DW_LANG_C99, file: !0, producer: "clang",
  ///                      isOptimized: true, flags: "-O2", runtimeVersion: 1,
  ///                      splitDebugFilename: "abc.debug",
  ///                      emissionKind: FullDebug, enums: !1, retainedTypes: !2,
  ///                      globals: !4, imports: !5, macros: !6, dwoId: 0x0abcd,
  ///                      sysroot: "/", sdk: "MacOSX.sdk")
  bool LLParser::parseDICompileUnit(MDNode *&Result, bool IsDistinct) {
    if (!IsDistinct)
      return Lex.Error("missing 'distinct', required for !DICompileUnit");
  
  #define VISIT_MD_FIELDS(OPTIONAL, REQUIRED)                                    \
    REQUIRED(language, DwarfLangField, );                                        \
    REQUIRED(file, MDField, (/* AllowNull */ false));                            \
    OPTIONAL(producer, MDStringField, );                                         \
    OPTIONAL(isOptimized, MDBoolField, );                                        \
    OPTIONAL(flags, MDStringField, );                                            \
    OPTIONAL(runtimeVersion, MDUnsignedField, (0, UINT32_MAX));                  \
    OPTIONAL(splitDebugFilename, MDStringField, );                               \
    OPTIONAL(emissionKind, EmissionKindField, );                                 \
    OPTIONAL(enums, MDField, );                                                  \
    OPTIONAL(retainedTypes, MDField, );                                          \
    OPTIONAL(globals, MDField, );                                                \
    OPTIONAL(imports, MDField, );                                                \
    OPTIONAL(macros, MDField, );                                                 \
    OPTIONAL(dwoId, MDUnsignedField, );                                          \
    OPTIONAL(splitDebugInlining, MDBoolField, = true);                           \
    OPTIONAL(debugInfoForProfiling, MDBoolField, = false);                       \
    OPTIONAL(nameTableKind, NameTableKindField, );                               \
    OPTIONAL(rangesBaseAddress, MDBoolField, = false);                           \
    OPTIONAL(sysroot, MDStringField, );                                          \
    OPTIONAL(sdk, MDStringField, );
    PARSE_MD_FIELDS();
  #undef VISIT_MD_FIELDS
  
    Result = DICompileUnit::getDistinct(
        Context, language.Val, file.Val, producer.Val, isOptimized.Val, flags.Val,
        runtimeVersion.Val, splitDebugFilename.Val, emissionKind.Val, enums.Val,
        retainedTypes.Val, globals.Val, imports.Val, macros.Val, dwoId.Val,
        splitDebugInlining.Val, debugInfoForProfiling.Val, nameTableKind.Val,
        rangesBaseAddress.Val, sysroot.Val, sdk.Val);
    return false;
  }
  
  /// parseDISubprogram:
  ///   ::= !DISubprogram(scope: !0, name: "foo", linkageName: "_Zfoo",
  ///                     file: !1, line: 7, type: !2, isLocal: false,
  ///                     isDefinition: true, scopeLine: 8, containingType: !3,
  ///                     virtuality: DW_VIRTUALTIY_pure_virtual,
  ///                     virtualIndex: 10, thisAdjustment: 4, flags: 11,
  ///                     spFlags: 10, isOptimized: false, templateParams: !4,
  ///                     declaration: !5, retainedNodes: !6, thrownTypes: !7,
  ///                     annotations: !8)
  bool LLParser::parseDISubprogram(MDNode *&Result, bool IsDistinct) {
    auto Loc = Lex.getLoc();
  #define VISIT_MD_FIELDS(OPTIONAL, REQUIRED)                                    \
    OPTIONAL(scope, MDField, );                                                  \
    OPTIONAL(name, MDStringField, );                                             \
    OPTIONAL(linkageName, MDStringField, );                                      \
    OPTIONAL(file, MDField, );                                                   \
    OPTIONAL(line, LineField, );                                                 \
    OPTIONAL(type, MDField, );                                                   \
    OPTIONAL(isLocal, MDBoolField, );                                            \
    OPTIONAL(isDefinition, MDBoolField, (true));                                 \
    OPTIONAL(scopeLine, LineField, );                                            \
    OPTIONAL(containingType, MDField, );                                         \
    OPTIONAL(virtuality, DwarfVirtualityField, );                                \
    OPTIONAL(virtualIndex, MDUnsignedField, (0, UINT32_MAX));                    \
    OPTIONAL(thisAdjustment, MDSignedField, (0, INT32_MIN, INT32_MAX));          \
    OPTIONAL(flags, DIFlagField, );                                              \
    OPTIONAL(spFlags, DISPFlagField, );                                          \
    OPTIONAL(isOptimized, MDBoolField, );                                        \
    OPTIONAL(unit, MDField, );                                                   \
    OPTIONAL(templateParams, MDField, );                                         \
    OPTIONAL(declaration, MDField, );                                            \
    OPTIONAL(retainedNodes, MDField, );                                          \
    OPTIONAL(thrownTypes, MDField, );                                            \
    OPTIONAL(annotations, MDField, );
    PARSE_MD_FIELDS();
  #undef VISIT_MD_FIELDS
  
    // An explicit spFlags field takes precedence over individual fields in
    // older IR versions.
    DISubprogram::DISPFlags SPFlags =
        spFlags.Seen ? spFlags.Val
                     : DISubprogram::toSPFlags(isLocal.Val, isDefinition.Val,
                                               isOptimized.Val, virtuality.Val);
    if ((SPFlags & DISubprogram::SPFlagDefinition) && !IsDistinct)
      return Lex.Error(
          Loc,
          "missing 'distinct', required for !DISubprogram that is a Definition");
    Result = GET_OR_DISTINCT(
        DISubprogram,
        (Context, scope.Val, name.Val, linkageName.Val, file.Val, line.Val,
         type.Val, scopeLine.Val, containingType.Val, virtualIndex.Val,
         thisAdjustment.Val, flags.Val, SPFlags, unit.Val, templateParams.Val,
         declaration.Val, retainedNodes.Val, thrownTypes.Val, annotations.Val));
    return false;
  }
  
  /// parseDILexicalBlock:
  ///   ::= !DILexicalBlock(scope: !0, file: !2, line: 7, column: 9)
  bool LLParser::parseDILexicalBlock(MDNode *&Result, bool IsDistinct) {
  #define VISIT_MD_FIELDS(OPTIONAL, REQUIRED)                                    \
    REQUIRED(scope, MDField, (/* AllowNull */ false));                           \
    OPTIONAL(file, MDField, );                                                   \
    OPTIONAL(line, LineField, );                                                 \
    OPTIONAL(column, ColumnField, );
    PARSE_MD_FIELDS();
  #undef VISIT_MD_FIELDS
  
    Result = GET_OR_DISTINCT(
        DILexicalBlock, (Context, scope.Val, file.Val, line.Val, column.Val));
    return false;
  }
  
  /// parseDILexicalBlockFile:
  ///   ::= !DILexicalBlockFile(scope: !0, file: !2, discriminator: 9)
  bool LLParser::parseDILexicalBlockFile(MDNode *&Result, bool IsDistinct) {
  #define VISIT_MD_FIELDS(OPTIONAL, REQUIRED)                                    \
    REQUIRED(scope, MDField, (/* AllowNull */ false));                           \
    OPTIONAL(file, MDField, );                                                   \
    REQUIRED(discriminator, MDUnsignedField, (0, UINT32_MAX));
    PARSE_MD_FIELDS();
  #undef VISIT_MD_FIELDS
  
    Result = GET_OR_DISTINCT(DILexicalBlockFile,
                             (Context, scope.Val, file.Val, discriminator.Val));
    return false;
  }
  
  /// parseDICommonBlock:
  ///   ::= !DICommonBlock(scope: !0, file: !2, name: "COMMON name", line: 9)
  bool LLParser::parseDICommonBlock(MDNode *&Result, bool IsDistinct) {
  #define VISIT_MD_FIELDS(OPTIONAL, REQUIRED)                                    \
    REQUIRED(scope, MDField, );                                                  \
    OPTIONAL(declaration, MDField, );                                            \
    OPTIONAL(name, MDStringField, );                                             \
    OPTIONAL(file, MDField, );                                                   \
    OPTIONAL(line, LineField, );
    PARSE_MD_FIELDS();
  #undef VISIT_MD_FIELDS
  
    Result = GET_OR_DISTINCT(DICommonBlock,
                             (Context, scope.Val, declaration.Val, name.Val,
                              file.Val, line.Val));
    return false;
  }
  
  /// parseDINamespace:
  ///   ::= !DINamespace(scope: !0, file: !2, name: "SomeNamespace", line: 9)
  bool LLParser::parseDINamespace(MDNode *&Result, bool IsDistinct) {
  #define VISIT_MD_FIELDS(OPTIONAL, REQUIRED)                                    \
    REQUIRED(scope, MDField, );                                                  \
    OPTIONAL(name, MDStringField, );                                             \
    OPTIONAL(exportSymbols, MDBoolField, );
    PARSE_MD_FIELDS();
  #undef VISIT_MD_FIELDS
  
    Result = GET_OR_DISTINCT(DINamespace,
                             (Context, scope.Val, name.Val, exportSymbols.Val));
    return false;
  }
  
  /// parseDIMacro:
  ///   ::= !DIMacro(macinfo: type, line: 9, name: "SomeMacro", value:
  ///   "SomeValue")
  bool LLParser::parseDIMacro(MDNode *&Result, bool IsDistinct) {
  #define VISIT_MD_FIELDS(OPTIONAL, REQUIRED)                                    \
    REQUIRED(type, DwarfMacinfoTypeField, );                                     \
    OPTIONAL(line, LineField, );                                                 \
    REQUIRED(name, MDStringField, );                                             \
    OPTIONAL(value, MDStringField, );
    PARSE_MD_FIELDS();
  #undef VISIT_MD_FIELDS
  
    Result = GET_OR_DISTINCT(DIMacro,
                             (Context, type.Val, line.Val, name.Val, value.Val));
    return false;
  }
  
  /// parseDIMacroFile:
  ///   ::= !DIMacroFile(line: 9, file: !2, nodes: !3)
  bool LLParser::parseDIMacroFile(MDNode *&Result, bool IsDistinct) {
  #define VISIT_MD_FIELDS(OPTIONAL, REQUIRED)                                    \
    OPTIONAL(type, DwarfMacinfoTypeField, (dwarf::DW_MACINFO_start_file));       \
    OPTIONAL(line, LineField, );                                                 \
    REQUIRED(file, MDField, );                                                   \
    OPTIONAL(nodes, MDField, );
    PARSE_MD_FIELDS();
  #undef VISIT_MD_FIELDS
  
    Result = GET_OR_DISTINCT(DIMacroFile,
                             (Context, type.Val, line.Val, file.Val, nodes.Val));
    return false;
  }
  
  /// parseDIModule:
  ///   ::= !DIModule(scope: !0, name: "SomeModule", configMacros:
  ///   "-DNDEBUG", includePath: "/usr/include", apinotes: "module.apinotes",
  ///   file: !1, line: 4, isDecl: false)
  bool LLParser::parseDIModule(MDNode *&Result, bool IsDistinct) {
  #define VISIT_MD_FIELDS(OPTIONAL, REQUIRED)                                    \
    REQUIRED(scope, MDField, );                                                  \
    REQUIRED(name, MDStringField, );                                             \
    OPTIONAL(configMacros, MDStringField, );                                     \
    OPTIONAL(includePath, MDStringField, );                                      \
    OPTIONAL(apinotes, MDStringField, );                                         \
    OPTIONAL(file, MDField, );                                                   \
    OPTIONAL(line, LineField, );                                                 \
    OPTIONAL(isDecl, MDBoolField, );
    PARSE_MD_FIELDS();
  #undef VISIT_MD_FIELDS
  
    Result = GET_OR_DISTINCT(DIModule, (Context, file.Val, scope.Val, name.Val,
                                        configMacros.Val, includePath.Val,
                                        apinotes.Val, line.Val, isDecl.Val));
    return false;
  }
  
  /// parseDITemplateTypeParameter:
  ///   ::= !DITemplateTypeParameter(name: "Ty", type: !1, defaulted: false)
  bool LLParser::parseDITemplateTypeParameter(MDNode *&Result, bool IsDistinct) {
  #define VISIT_MD_FIELDS(OPTIONAL, REQUIRED)                                    \
    OPTIONAL(name, MDStringField, );                                             \
    REQUIRED(type, MDField, );                                                   \
    OPTIONAL(defaulted, MDBoolField, );
    PARSE_MD_FIELDS();
  #undef VISIT_MD_FIELDS
  
    Result = GET_OR_DISTINCT(DITemplateTypeParameter,
                             (Context, name.Val, type.Val, defaulted.Val));
    return false;
  }
  
  /// parseDITemplateValueParameter:
  ///   ::= !DITemplateValueParameter(tag: DW_TAG_template_value_parameter,
  ///                                 name: "V", type: !1, defaulted: false,
  ///                                 value: i32 7)
  bool LLParser::parseDITemplateValueParameter(MDNode *&Result, bool IsDistinct) {
  #define VISIT_MD_FIELDS(OPTIONAL, REQUIRED)                                    \
    OPTIONAL(tag, DwarfTagField, (dwarf::DW_TAG_template_value_parameter));      \
    OPTIONAL(name, MDStringField, );                                             \
    OPTIONAL(type, MDField, );                                                   \
    OPTIONAL(defaulted, MDBoolField, );                                          \
    REQUIRED(value, MDField, );
  
    PARSE_MD_FIELDS();
  #undef VISIT_MD_FIELDS
  
    Result = GET_OR_DISTINCT(
        DITemplateValueParameter,
        (Context, tag.Val, name.Val, type.Val, defaulted.Val, value.Val));
    return false;
  }
  
  /// parseDIGlobalVariable:
  ///   ::= !DIGlobalVariable(scope: !0, name: "foo", linkageName: "foo",
  ///                         file: !1, line: 7, type: !2, isLocal: false,
  ///                         isDefinition: true, templateParams: !3,
  ///                         declaration: !4, align: 8)
  bool LLParser::parseDIGlobalVariable(MDNode *&Result, bool IsDistinct) {
  #define VISIT_MD_FIELDS(OPTIONAL, REQUIRED)                                    \
    REQUIRED(name, MDStringField, (/* AllowEmpty */ false));                     \
    OPTIONAL(scope, MDField, );                                                  \
    OPTIONAL(linkageName, MDStringField, );                                      \
    OPTIONAL(file, MDField, );                                                   \
    OPTIONAL(line, LineField, );                                                 \
    OPTIONAL(type, MDField, );                                                   \
    OPTIONAL(isLocal, MDBoolField, );                                            \
    OPTIONAL(isDefinition, MDBoolField, (true));                                 \
    OPTIONAL(templateParams, MDField, );                                         \
    OPTIONAL(declaration, MDField, );                                            \
    OPTIONAL(align, MDUnsignedField, (0, UINT32_MAX));                           \
    OPTIONAL(annotations, MDField, );
    PARSE_MD_FIELDS();
  #undef VISIT_MD_FIELDS
  
    Result =
        GET_OR_DISTINCT(DIGlobalVariable,
                        (Context, scope.Val, name.Val, linkageName.Val, file.Val,
                         line.Val, type.Val, isLocal.Val, isDefinition.Val,
                         declaration.Val, templateParams.Val, align.Val,
                         annotations.Val));
    return false;
  }
  
  /// parseDILocalVariable:
  ///   ::= !DILocalVariable(arg: 7, scope: !0, name: "foo",
  ///                        file: !1, line: 7, type: !2, arg: 2, flags: 7,
  ///                        align: 8)
  ///   ::= !DILocalVariable(scope: !0, name: "foo",
  ///                        file: !1, line: 7, type: !2, arg: 2, flags: 7,
  ///                        align: 8)
  bool LLParser::parseDILocalVariable(MDNode *&Result, bool IsDistinct) {
  #define VISIT_MD_FIELDS(OPTIONAL, REQUIRED)                                    \
    REQUIRED(scope, MDField, (/* AllowNull */ false));                           \
    OPTIONAL(name, MDStringField, );                                             \
    OPTIONAL(arg, MDUnsignedField, (0, UINT16_MAX));                             \
    OPTIONAL(file, MDField, );                                                   \
    OPTIONAL(line, LineField, );                                                 \
    OPTIONAL(type, MDField, );                                                   \
    OPTIONAL(flags, DIFlagField, );                                              \
    OPTIONAL(align, MDUnsignedField, (0, UINT32_MAX));                           \
    OPTIONAL(annotations, MDField, );
    PARSE_MD_FIELDS();
  #undef VISIT_MD_FIELDS
  
    Result = GET_OR_DISTINCT(DILocalVariable,
                             (Context, scope.Val, name.Val, file.Val, line.Val,
                              type.Val, arg.Val, flags.Val, align.Val,
                              annotations.Val));
    return false;
  }
  
  /// parseDILabel:
  ///   ::= !DILabel(scope: !0, name: "foo", file: !1, line: 7)
  bool LLParser::parseDILabel(MDNode *&Result, bool IsDistinct) {
  #define VISIT_MD_FIELDS(OPTIONAL, REQUIRED)                                    \
    REQUIRED(scope, MDField, (/* AllowNull */ false));                           \
    REQUIRED(name, MDStringField, );                                             \
    REQUIRED(file, MDField, );                                                   \
    REQUIRED(line, LineField, );
    PARSE_MD_FIELDS();
  #undef VISIT_MD_FIELDS
  
    Result = GET_OR_DISTINCT(DILabel,
                             (Context, scope.Val, name.Val, file.Val, line.Val));
    return false;
  }
  
  /// parseDIExpression:
  ///   ::= !DIExpression(0, 7, -1)
  bool LLParser::parseDIExpression(MDNode *&Result, bool IsDistinct) {
    assert(Lex.getKind() == lltok::MetadataVar && "Expected metadata type name");
    Lex.Lex();
  
    if (parseToken(lltok::lparen, "expected '(' here"))
      return true;
  
    SmallVector<uint64_t, 8> Elements;
    if (Lex.getKind() != lltok::rparen)
      do {
        if (Lex.getKind() == lltok::DwarfOp) {
          if (unsigned Op = dwarf::getOperationEncoding(Lex.getStrVal())) {
            Lex.Lex();
            Elements.push_back(Op);
            continue;
          }
          return tokError(Twine("invalid DWARF op '") + Lex.getStrVal() + "'");
        }
  
        if (Lex.getKind() == lltok::DwarfAttEncoding) {
          if (unsigned Op = dwarf::getAttributeEncoding(Lex.getStrVal())) {
            Lex.Lex();
            Elements.push_back(Op);
            continue;
          }
          return tokError(Twine("invalid DWARF attribute encoding '") +
                          Lex.getStrVal() + "'");
        }
  
        if (Lex.getKind() != lltok::APSInt || Lex.getAPSIntVal().isSigned())
          return tokError("expected unsigned integer");
  
        auto &U = Lex.getAPSIntVal();
        if (U.ugt(UINT64_MAX))
          return tokError("element too large, limit is " + Twine(UINT64_MAX));
        Elements.push_back(U.getZExtValue());
        Lex.Lex();
      } while (EatIfPresent(lltok::comma));
  
    if (parseToken(lltok::rparen, "expected ')' here"))
      return true;
  
    Result = GET_OR_DISTINCT(DIExpression, (Context, Elements));
    return false;
  }
  
  bool LLParser::parseDIArgList(MDNode *&Result, bool IsDistinct) {
    return parseDIArgList(Result, IsDistinct, nullptr);
  }
  /// ParseDIArgList:
  ///   ::= !DIArgList(i32 7, i64 %0)
  bool LLParser::parseDIArgList(MDNode *&Result, bool IsDistinct,
                                PerFunctionState *PFS) {
    assert(PFS && "Expected valid function state");
    assert(Lex.getKind() == lltok::MetadataVar && "Expected metadata type name");
    Lex.Lex();
  
    if (parseToken(lltok::lparen, "expected '(' here"))
      return true;
  
    SmallVector<ValueAsMetadata *, 4> Args;
    if (Lex.getKind() != lltok::rparen)
      do {
        Metadata *MD;
        if (parseValueAsMetadata(MD, "expected value-as-metadata operand", PFS))
          return true;
        Args.push_back(dyn_cast<ValueAsMetadata>(MD));
      } while (EatIfPresent(lltok::comma));
  
    if (parseToken(lltok::rparen, "expected ')' here"))
      return true;
  
    Result = GET_OR_DISTINCT(DIArgList, (Context, Args));
    return false;
  }
  
  /// parseDIGlobalVariableExpression:
  ///   ::= !DIGlobalVariableExpression(var: !0, expr: !1)
  bool LLParser::parseDIGlobalVariableExpression(MDNode *&Result,
                                                 bool IsDistinct) {
  #define VISIT_MD_FIELDS(OPTIONAL, REQUIRED)                                    \
    REQUIRED(var, MDField, );                                                    \
    REQUIRED(expr, MDField, );
    PARSE_MD_FIELDS();
  #undef VISIT_MD_FIELDS
  
    Result =
        GET_OR_DISTINCT(DIGlobalVariableExpression, (Context, var.Val, expr.Val));
    return false;
  }
  
  /// parseDIObjCProperty:
  ///   ::= !DIObjCProperty(name: "foo", file: !1, line: 7, setter: "setFoo",
  ///                       getter: "getFoo", attributes: 7, type: !2)
  bool LLParser::parseDIObjCProperty(MDNode *&Result, bool IsDistinct) {
  #define VISIT_MD_FIELDS(OPTIONAL, REQUIRED)                                    \
    OPTIONAL(name, MDStringField, );                                             \
    OPTIONAL(file, MDField, );                                                   \
    OPTIONAL(line, LineField, );                                                 \
    OPTIONAL(setter, MDStringField, );                                           \
    OPTIONAL(getter, MDStringField, );                                           \
    OPTIONAL(attributes, MDUnsignedField, (0, UINT32_MAX));                      \
    OPTIONAL(type, MDField, );
    PARSE_MD_FIELDS();
  #undef VISIT_MD_FIELDS
  
    Result = GET_OR_DISTINCT(DIObjCProperty,
                             (Context, name.Val, file.Val, line.Val, setter.Val,
                              getter.Val, attributes.Val, type.Val));
    return false;
  }
  
  /// parseDIImportedEntity:
  ///   ::= !DIImportedEntity(tag: DW_TAG_imported_module, scope: !0, entity: !1,
  ///                         line: 7, name: "foo", elements: !2)
  bool LLParser::parseDIImportedEntity(MDNode *&Result, bool IsDistinct) {
  #define VISIT_MD_FIELDS(OPTIONAL, REQUIRED)                                    \
    REQUIRED(tag, DwarfTagField, );                                              \
    REQUIRED(scope, MDField, );                                                  \
    OPTIONAL(entity, MDField, );                                                 \
    OPTIONAL(file, MDField, );                                                   \
    OPTIONAL(line, LineField, );                                                 \
    OPTIONAL(name, MDStringField, );                                             \
    OPTIONAL(elements, MDField, );
    PARSE_MD_FIELDS();
  #undef VISIT_MD_FIELDS
  
    Result = GET_OR_DISTINCT(DIImportedEntity,
                             (Context, tag.Val, scope.Val, entity.Val, file.Val,
                              line.Val, name.Val, elements.Val));
    return false;
  }
  
  #undef PARSE_MD_FIELD
  #undef NOP_FIELD
  #undef REQUIRE_FIELD
  #undef DECLARE_FIELD
  
  /// parseMetadataAsValue
  ///  ::= metadata i32 %local
  ///  ::= metadata i32 @global
  ///  ::= metadata i32 7
  ///  ::= metadata !0
  ///  ::= metadata !{...}
  ///  ::= metadata !"string"
  bool LLParser::parseMetadataAsValue(Value *&V, PerFunctionState &PFS) {
    // Note: the type 'metadata' has already been parsed.
    Metadata *MD;
    if (parseMetadata(MD, &PFS))
      return true;
  
    V = MetadataAsValue::get(Context, MD);
    return false;
  }
  
  /// parseValueAsMetadata
  ///  ::= i32 %local
  ///  ::= i32 @global
  ///  ::= i32 7
  bool LLParser::parseValueAsMetadata(Metadata *&MD, const Twine &TypeMsg,
                                      PerFunctionState *PFS) {
    Type *Ty;
    LocTy Loc;
    if (parseType(Ty, TypeMsg, Loc))
      return true;
    if (Ty->isMetadataTy())
      return error(Loc, "invalid metadata-value-metadata roundtrip");
  
    Value *V;
    if (parseValue(Ty, V, PFS))
      return true;
  
    MD = ValueAsMetadata::get(V);
    return false;
  }
  
  /// parseMetadata
  ///  ::= i32 %local
  ///  ::= i32 @global
  ///  ::= i32 7
  ///  ::= !42
  ///  ::= !{...}
  ///  ::= !"string"
  ///  ::= !DILocation(...)
  bool LLParser::parseMetadata(Metadata *&MD, PerFunctionState *PFS) {
    if (Lex.getKind() == lltok::MetadataVar) {
      MDNode *N;
      // DIArgLists are a special case, as they are a list of ValueAsMetadata and
      // so parsing this requires a Function State.
      if (Lex.getStrVal() == "DIArgList") {
        if (parseDIArgList(N, false, PFS))
          return true;
      } else if (parseSpecializedMDNode(N)) {
        return true;
      }
      MD = N;
      return false;
    }
  
    // ValueAsMetadata:
    // <type> <value>
    if (Lex.getKind() != lltok::exclaim)
      return parseValueAsMetadata(MD, "expected metadata operand", PFS);
  
    // '!'.
    assert(Lex.getKind() == lltok::exclaim && "Expected '!' here");
    Lex.Lex();
  
    // MDString:
    //   ::= '!' STRINGCONSTANT
    if (Lex.getKind() == lltok::StringConstant) {
      MDString *S;
      if (parseMDString(S))
        return true;
      MD = S;
      return false;
    }
  
    // MDNode:
    // !{ ... }
    // !7
    MDNode *N;
    if (parseMDNodeTail(N))
      return true;
    MD = N;
    return false;
  }
  
  //===----------------------------------------------------------------------===//
  // Function Parsing.
  //===----------------------------------------------------------------------===//
  
  bool LLParser::convertValIDToValue(Type *Ty, ValID &ID, Value *&V,
                                     PerFunctionState *PFS) {
    if (Ty->isFunctionTy())
      return error(ID.Loc, "functions are not values, refer to them as pointers");
  
    switch (ID.Kind) {
    case ValID::t_LocalID:
      if (!PFS)
        return error(ID.Loc, "invalid use of function-local name");
      V = PFS->getVal(ID.UIntVal, Ty, ID.Loc);
      return V == nullptr;
    case ValID::t_LocalName:
      if (!PFS)
        return error(ID.Loc, "invalid use of function-local name");
      V = PFS->getVal(ID.StrVal, Ty, ID.Loc);
      return V == nullptr;
    case ValID::t_InlineAsm: {
      if (!ID.FTy || !InlineAsm::Verify(ID.FTy, ID.StrVal2))
        return error(ID.Loc, "invalid type for inline asm constraint string");
      V = InlineAsm::get(
          ID.FTy, ID.StrVal, ID.StrVal2, ID.UIntVal & 1, (ID.UIntVal >> 1) & 1,
          InlineAsm::AsmDialect((ID.UIntVal >> 2) & 1), (ID.UIntVal >> 3) & 1);
      return false;
    }
    case ValID::t_GlobalName:
      V = getGlobalVal(ID.StrVal, Ty, ID.Loc);
      return V == nullptr;
    case ValID::t_GlobalID:
      V = getGlobalVal(ID.UIntVal, Ty, ID.Loc);
      return V == nullptr;
    case ValID::t_APSInt:
      if (!Ty->isIntegerTy())
        return error(ID.Loc, "integer constant must have integer type");
      ID.APSIntVal = ID.APSIntVal.extOrTrunc(Ty->getPrimitiveSizeInBits());
      V = ConstantInt::get(Context, ID.APSIntVal);
      return false;
    case ValID::t_APFloat:
      if (!Ty->isFloatingPointTy() ||
          !ConstantFP::isValueValidForType(Ty, ID.APFloatVal))
        return error(ID.Loc, "floating point constant invalid for type");
  
      // The lexer has no type info, so builds all half, bfloat, float, and double
      // FP constants as double.  Fix this here.  Long double does not need this.
      if (&ID.APFloatVal.getSemantics() == &APFloat::IEEEdouble()) {
        // Check for signaling before potentially converting and losing that info.
        bool IsSNAN = ID.APFloatVal.isSignaling();
        bool Ignored;
        if (Ty->isHalfTy())
          ID.APFloatVal.convert(APFloat::IEEEhalf(), APFloat::rmNearestTiesToEven,
                                &Ignored);
        else if (Ty->isBFloatTy())
          ID.APFloatVal.convert(APFloat::BFloat(), APFloat::rmNearestTiesToEven,
                                &Ignored);
        else if (Ty->isFloatTy())
          ID.APFloatVal.convert(APFloat::IEEEsingle(), APFloat::rmNearestTiesToEven,
                                &Ignored);
        if (IsSNAN) {
          // The convert call above may quiet an SNaN, so manufacture another
          // SNaN. The bitcast works because the payload (significand) parameter
          // is truncated to fit.
          APInt Payload = ID.APFloatVal.bitcastToAPInt();
          ID.APFloatVal = APFloat::getSNaN(ID.APFloatVal.getSemantics(),
                                           ID.APFloatVal.isNegative(), &Payload);
        }
      }
      V = ConstantFP::get(Context, ID.APFloatVal);
  
      if (V->getType() != Ty)
        return error(ID.Loc, "floating point constant does not have type '" +
                                 getTypeString(Ty) + "'");
  
      return false;
    case ValID::t_Null:
      if (!Ty->isPointerTy())
        return error(ID.Loc, "null must be a pointer type");
      V = ConstantPointerNull::get(cast<PointerType>(Ty));
      return false;
    case ValID::t_Undef:
      // FIXME: LabelTy should not be a first-class type.
      if (!Ty->isFirstClassType() || Ty->isLabelTy())
        return error(ID.Loc, "invalid type for undef constant");
      V = UndefValue::get(Ty);
      return false;
    case ValID::t_EmptyArray:
      if (!Ty->isArrayTy() || cast<ArrayType>(Ty)->getNumElements() != 0)
        return error(ID.Loc, "invalid empty array initializer");
      V = UndefValue::get(Ty);
      return false;
    case ValID::t_Zero:
      // FIXME: LabelTy should not be a first-class type.
      if (!Ty->isFirstClassType() || Ty->isLabelTy())
        return error(ID.Loc, "invalid type for null constant");
      V = Constant::getNullValue(Ty);
      return false;
    case ValID::t_None:
      if (!Ty->isTokenTy())
        return error(ID.Loc, "invalid type for none constant");
      V = Constant::getNullValue(Ty);
      return false;
    case ValID::t_Poison:
      // FIXME: LabelTy should not be a first-class type.
      if (!Ty->isFirstClassType() || Ty->isLabelTy())
        return error(ID.Loc, "invalid type for poison constant");
      V = PoisonValue::get(Ty);
      return false;
    case ValID::t_Constant:
      if (ID.ConstantVal->getType() != Ty)
        return error(ID.Loc, "constant expression type mismatch: got type '" +
                                 getTypeString(ID.ConstantVal->getType()) +
                                 "' but expected '" + getTypeString(Ty) + "'");
      V = ID.ConstantVal;
      return false;
    case ValID::t_ConstantStruct:
    case ValID::t_PackedConstantStruct:
      if (StructType *ST = dyn_cast<StructType>(Ty)) {
        if (ST->getNumElements() != ID.UIntVal)
          return error(ID.Loc,
                       "initializer with struct type has wrong # elements");
        if (ST->isPacked() != (ID.Kind == ValID::t_PackedConstantStruct))
          return error(ID.Loc, "packed'ness of initializer and type don't match");
  
        // Verify that the elements are compatible with the structtype.
        for (unsigned i = 0, e = ID.UIntVal; i != e; ++i)
          if (ID.ConstantStructElts[i]->getType() != ST->getElementType(i))
            return error(
                ID.Loc,
                "element " + Twine(i) +
                    " of struct initializer doesn't match struct element type");
  
        V = ConstantStruct::get(
            ST, makeArrayRef(ID.ConstantStructElts.get(), ID.UIntVal));
      } else
        return error(ID.Loc, "constant expression type mismatch");
      return false;
    }
    llvm_unreachable("Invalid ValID");
  }
  
  bool LLParser::parseConstantValue(Type *Ty, Constant *&C) {
    C = nullptr;
    ValID ID;
    auto Loc = Lex.getLoc();
    if (parseValID(ID, /*PFS=*/nullptr))
      return true;
    switch (ID.Kind) {
    case ValID::t_APSInt:
    case ValID::t_APFloat:
    case ValID::t_Undef:
    case ValID::t_Constant:
    case ValID::t_ConstantStruct:
    case ValID::t_PackedConstantStruct: {
      Value *V;
      if (convertValIDToValue(Ty, ID, V, /*PFS=*/nullptr))
        return true;
      assert(isa<Constant>(V) && "Expected a constant value");
      C = cast<Constant>(V);
      return false;
    }
    case ValID::t_Null:
      C = Constant::getNullValue(Ty);
      return false;
    default:
      return error(Loc, "expected a constant value");
    }
  }
  
  bool LLParser::parseValue(Type *Ty, Value *&V, PerFunctionState *PFS) {
    V = nullptr;
    ValID ID;
    return parseValID(ID, PFS, Ty) ||
           convertValIDToValue(Ty, ID, V, PFS);
  }
  
  bool LLParser::parseTypeAndValue(Value *&V, PerFunctionState *PFS) {
    Type *Ty = nullptr;
    return parseType(Ty) || parseValue(Ty, V, PFS);
  }
  
  bool LLParser::parseTypeAndBasicBlock(BasicBlock *&BB, LocTy &Loc,
                                        PerFunctionState &PFS) {
    Value *V;
    Loc = Lex.getLoc();
    if (parseTypeAndValue(V, PFS))
      return true;
    if (!isa<BasicBlock>(V))
      return error(Loc, "expected a basic block");
    BB = cast<BasicBlock>(V);
    return false;
  }
  
  /// FunctionHeader
  ///   ::= OptionalLinkage OptionalPreemptionSpecifier OptionalVisibility
  ///       OptionalCallingConv OptRetAttrs OptUnnamedAddr Type GlobalName
  ///       '(' ArgList ')' OptAddrSpace OptFuncAttrs OptSection OptionalAlign
  ///       OptGC OptionalPrefix OptionalPrologue OptPersonalityFn
  bool LLParser::parseFunctionHeader(Function *&Fn, bool IsDefine) {
    // parse the linkage.
    LocTy LinkageLoc = Lex.getLoc();
    unsigned Linkage;
    unsigned Visibility;
    unsigned DLLStorageClass;
    bool DSOLocal;
    AttrBuilder RetAttrs;
    unsigned CC;
    bool HasLinkage;
    Type *RetType = nullptr;
    LocTy RetTypeLoc = Lex.getLoc();
    if (parseOptionalLinkage(Linkage, HasLinkage, Visibility, DLLStorageClass,
                             DSOLocal) ||
        parseOptionalCallingConv(CC) || parseOptionalReturnAttrs(RetAttrs) ||
        parseType(RetType, RetTypeLoc, true /*void allowed*/))
      return true;
  
    // Verify that the linkage is ok.
    switch ((GlobalValue::LinkageTypes)Linkage) {
    case GlobalValue::ExternalLinkage:
      break; // always ok.
    case GlobalValue::ExternalWeakLinkage:
      if (IsDefine)
        return error(LinkageLoc, "invalid linkage for function definition");
      break;
    case GlobalValue::PrivateLinkage:
    case GlobalValue::InternalLinkage:
    case GlobalValue::AvailableExternallyLinkage:
    case GlobalValue::LinkOnceAnyLinkage:
    case GlobalValue::LinkOnceODRLinkage:
    case GlobalValue::WeakAnyLinkage:
    case GlobalValue::WeakODRLinkage:
      if (!IsDefine)
        return error(LinkageLoc, "invalid linkage for function declaration");
      break;
    case GlobalValue::AppendingLinkage:
    case GlobalValue::CommonLinkage:
      return error(LinkageLoc, "invalid function linkage type");
    }
  
    if (!isValidVisibilityForLinkage(Visibility, Linkage))
      return error(LinkageLoc,
                   "symbol with local linkage must have default visibility");
  
    if (!FunctionType::isValidReturnType(RetType))
      return error(RetTypeLoc, "invalid function return type");
  
    LocTy NameLoc = Lex.getLoc();
  
    std::string FunctionName;
    if (Lex.getKind() == lltok::GlobalVar) {
      FunctionName = Lex.getStrVal();
    } else if (Lex.getKind() == lltok::GlobalID) {     // @42 is ok.
      unsigned NameID = Lex.getUIntVal();
  
      if (NameID != NumberedVals.size())
        return tokError("function expected to be numbered '%" +
                        Twine(NumberedVals.size()) + "'");
    } else {
      return tokError("expected function name");
    }
  
    Lex.Lex();
  
    if (Lex.getKind() != lltok::lparen)
      return tokError("expected '(' in function argument list");
  
    SmallVector<ArgInfo, 8> ArgList;
    bool IsVarArg;
    AttrBuilder FuncAttrs;
    std::vector<unsigned> FwdRefAttrGrps;
    LocTy BuiltinLoc;
    std::string Section;
    std::string Partition;
    MaybeAlign Alignment;
    std::string GC;
    GlobalValue::UnnamedAddr UnnamedAddr = GlobalValue::UnnamedAddr::None;
    unsigned AddrSpace = 0;
    Constant *Prefix = nullptr;
    Constant *Prologue = nullptr;
    Constant *PersonalityFn = nullptr;
    Comdat *C;
  
    if (parseArgumentList(ArgList, IsVarArg) ||
        parseOptionalUnnamedAddr(UnnamedAddr) ||
        parseOptionalProgramAddrSpace(AddrSpace) ||
        parseFnAttributeValuePairs(FuncAttrs, FwdRefAttrGrps, false,
                                   BuiltinLoc) ||
        (EatIfPresent(lltok::kw_section) && parseStringConstant(Section)) ||
        (EatIfPresent(lltok::kw_partition) && parseStringConstant(Partition)) ||
        parseOptionalComdat(FunctionName, C) ||
        parseOptionalAlignment(Alignment) ||
        (EatIfPresent(lltok::kw_gc) && parseStringConstant(GC)) ||
        (EatIfPresent(lltok::kw_prefix) && parseGlobalTypeAndValue(Prefix)) ||
        (EatIfPresent(lltok::kw_prologue) && parseGlobalTypeAndValue(Prologue)) ||
        (EatIfPresent(lltok::kw_personality) &&
         parseGlobalTypeAndValue(PersonalityFn)))
      return true;
  
    if (FuncAttrs.contains(Attribute::Builtin))
      return error(BuiltinLoc, "'builtin' attribute not valid on function");
  
    // If the alignment was parsed as an attribute, move to the alignment field.
    if (FuncAttrs.hasAlignmentAttr()) {
      Alignment = FuncAttrs.getAlignment();
      FuncAttrs.removeAttribute(Attribute::Alignment);
    }
  
    // Okay, if we got here, the function is syntactically valid.  Convert types
    // and do semantic checks.
    std::vector<Type*> ParamTypeList;
    SmallVector<AttributeSet, 8> Attrs;
  
    for (unsigned i = 0, e = ArgList.size(); i != e; ++i) {
      ParamTypeList.push_back(ArgList[i].Ty);
      Attrs.push_back(ArgList[i].Attrs);
    }
  
    AttributeList PAL =
        AttributeList::get(Context, AttributeSet::get(Context, FuncAttrs),
                           AttributeSet::get(Context, RetAttrs), Attrs);
  
    if (PAL.hasParamAttr(0, Attribute::StructRet) && !RetType->isVoidTy())
      return error(RetTypeLoc, "functions with 'sret' argument must return void");
  
    FunctionType *FT = FunctionType::get(RetType, ParamTypeList, IsVarArg);
    PointerType *PFT = PointerType::get(FT, AddrSpace);
  
    Fn = nullptr;
    GlobalValue *FwdFn = nullptr;
    if (!FunctionName.empty()) {
      // If this was a definition of a forward reference, remove the definition
      // from the forward reference table and fill in the forward ref.
      auto FRVI = ForwardRefVals.find(FunctionName);
      if (FRVI != ForwardRefVals.end()) {
        FwdFn = FRVI->second.first;
        if (!FwdFn->getType()->isOpaque()) {
          if (!FwdFn->getType()->getPointerElementType()->isFunctionTy())
            return error(FRVI->second.second, "invalid forward reference to "
                                              "function as global value!");
          if (FwdFn->getType() != PFT)
            return error(FRVI->second.second,
                         "invalid forward reference to "
                         "function '" +
                             FunctionName +
                             "' with wrong type: "
                             "expected '" +
                             getTypeString(PFT) + "' but was '" +
                             getTypeString(FwdFn->getType()) + "'");
        }
        ForwardRefVals.erase(FRVI);
      } else if ((Fn = M->getFunction(FunctionName))) {
        // Reject redefinitions.
        return error(NameLoc,
                     "invalid redefinition of function '" + FunctionName + "'");
      } else if (M->getNamedValue(FunctionName)) {
        return error(NameLoc, "redefinition of function '@" + FunctionName + "'");
      }
  
    } else {
      // If this is a definition of a forward referenced function, make sure the
      // types agree.
      auto I = ForwardRefValIDs.find(NumberedVals.size());
      if (I != ForwardRefValIDs.end()) {
        FwdFn = cast<Function>(I->second.first);
        if (!FwdFn->getType()->isOpaque() && FwdFn->getType() != PFT)
          return error(NameLoc, "type of definition and forward reference of '@" +
                                    Twine(NumberedVals.size()) +
                                    "' disagree: "
                                    "expected '" +
                                    getTypeString(PFT) + "' but was '" +
                                    getTypeString(FwdFn->getType()) + "'");
        ForwardRefValIDs.erase(I);
      }
    }
  
    Fn = Function::Create(FT, GlobalValue::ExternalLinkage, AddrSpace,
                          FunctionName, M);
  
    assert(Fn->getAddressSpace() == AddrSpace && "Created function in wrong AS");
  
    if (FunctionName.empty())
      NumberedVals.push_back(Fn);
  
    Fn->setLinkage((GlobalValue::LinkageTypes)Linkage);
    maybeSetDSOLocal(DSOLocal, *Fn);
    Fn->setVisibility((GlobalValue::VisibilityTypes)Visibility);
    Fn->setDLLStorageClass((GlobalValue::DLLStorageClassTypes)DLLStorageClass);
    Fn->setCallingConv(CC);
    Fn->setAttributes(PAL);
    Fn->setUnnamedAddr(UnnamedAddr);
    Fn->setAlignment(MaybeAlign(Alignment));
    Fn->setSection(Section);
    Fn->setPartition(Partition);
    Fn->setComdat(C);
    Fn->setPersonalityFn(PersonalityFn);
    if (!GC.empty()) Fn->setGC(GC);
    Fn->setPrefixData(Prefix);
    Fn->setPrologueData(Prologue);
    ForwardRefAttrGroups[Fn] = FwdRefAttrGrps;
  
    // Add all of the arguments we parsed to the function.
    Function::arg_iterator ArgIt = Fn->arg_begin();
    for (unsigned i = 0, e = ArgList.size(); i != e; ++i, ++ArgIt) {
      // If the argument has a name, insert it into the argument symbol table.
      if (ArgList[i].Name.empty()) continue;
  
      // Set the name, if it conflicted, it will be auto-renamed.
      ArgIt->setName(ArgList[i].Name);
  
      if (ArgIt->getName() != ArgList[i].Name)
        return error(ArgList[i].Loc,
                     "redefinition of argument '%" + ArgList[i].Name + "'");
    }
  
    if (FwdFn) {
      FwdFn->replaceAllUsesWith(Fn);
      FwdFn->eraseFromParent();
    }
  
    if (IsDefine)
      return false;
  
    // Check the declaration has no block address forward references.
    ValID ID;
    if (FunctionName.empty()) {
      ID.Kind = ValID::t_GlobalID;
      ID.UIntVal = NumberedVals.size() - 1;
    } else {
      ID.Kind = ValID::t_GlobalName;
      ID.StrVal = FunctionName;
    }
    auto Blocks = ForwardRefBlockAddresses.find(ID);
    if (Blocks != ForwardRefBlockAddresses.end())
      return error(Blocks->first.Loc,
                   "cannot take blockaddress inside a declaration");
    return false;
  }
  
  bool LLParser::PerFunctionState::resolveForwardRefBlockAddresses() {
    ValID ID;
    if (FunctionNumber == -1) {
      ID.Kind = ValID::t_GlobalName;
      ID.StrVal = std::string(F.getName());
    } else {
      ID.Kind = ValID::t_GlobalID;
      ID.UIntVal = FunctionNumber;
    }
  
    auto Blocks = P.ForwardRefBlockAddresses.find(ID);
    if (Blocks == P.ForwardRefBlockAddresses.end())
      return false;
  
    for (const auto &I : Blocks->second) {
      const ValID &BBID = I.first;
      GlobalValue *GV = I.second;
  
      assert((BBID.Kind == ValID::t_LocalID || BBID.Kind == ValID::t_LocalName) &&
             "Expected local id or name");
      BasicBlock *BB;
      if (BBID.Kind == ValID::t_LocalName)
        BB = getBB(BBID.StrVal, BBID.Loc);
      else
        BB = getBB(BBID.UIntVal, BBID.Loc);
      if (!BB)
        return P.error(BBID.Loc, "referenced value is not a basic block");
  
      Value *ResolvedVal = BlockAddress::get(&F, BB);
      ResolvedVal = P.checkValidVariableType(BBID.Loc, BBID.StrVal, GV->getType(),
                                             ResolvedVal);
      if (!ResolvedVal)
        return true;
      GV->replaceAllUsesWith(ResolvedVal);
      GV->eraseFromParent();
    }
  
    P.ForwardRefBlockAddresses.erase(Blocks);
    return false;
  }
  
  /// parseFunctionBody
  ///   ::= '{' BasicBlock+ UseListOrderDirective* '}'
  bool LLParser::parseFunctionBody(Function &Fn) {
    if (Lex.getKind() != lltok::lbrace)
      return tokError("expected '{' in function body");
    Lex.Lex();  // eat the {.
  
    int FunctionNumber = -1;
    if (!Fn.hasName()) FunctionNumber = NumberedVals.size()-1;
  
    PerFunctionState PFS(*this, Fn, FunctionNumber);
  
    // Resolve block addresses and allow basic blocks to be forward-declared
    // within this function.
    if (PFS.resolveForwardRefBlockAddresses())
      return true;
    SaveAndRestore<PerFunctionState *> ScopeExit(BlockAddressPFS, &PFS);
  
    // We need at least one basic block.
    if (Lex.getKind() == lltok::rbrace || Lex.getKind() == lltok::kw_uselistorder)
      return tokError("function body requires at least one basic block");
  
    while (Lex.getKind() != lltok::rbrace &&
           Lex.getKind() != lltok::kw_uselistorder)
      if (parseBasicBlock(PFS))
        return true;
  
    while (Lex.getKind() != lltok::rbrace)
      if (parseUseListOrder(&PFS))
        return true;
  
    // Eat the }.
    Lex.Lex();
  
    // Verify function is ok.
    return PFS.finishFunction();
  }
  
  /// parseBasicBlock
  ///   ::= (LabelStr|LabelID)? Instruction*
  bool LLParser::parseBasicBlock(PerFunctionState &PFS) {
    // If this basic block starts out with a name, remember it.
    std::string Name;
    int NameID = -1;
    LocTy NameLoc = Lex.getLoc();
    if (Lex.getKind() == lltok::LabelStr) {
      Name = Lex.getStrVal();
      Lex.Lex();
    } else if (Lex.getKind() == lltok::LabelID) {
      NameID = Lex.getUIntVal();
      Lex.Lex();
    }
  
    BasicBlock *BB = PFS.defineBB(Name, NameID, NameLoc);
    if (!BB)
      return true;
  
    std::string NameStr;
  
    // parse the instructions in this block until we get a terminator.
    Instruction *Inst;
    do {
      // This instruction may have three possibilities for a name: a) none
      // specified, b) name specified "%foo =", c) number specified: "%4 =".
      LocTy NameLoc = Lex.getLoc();
      int NameID = -1;
      NameStr = "";
  
      if (Lex.getKind() == lltok::LocalVarID) {
        NameID = Lex.getUIntVal();
        Lex.Lex();
        if (parseToken(lltok::equal, "expected '=' after instruction id"))
          return true;
      } else if (Lex.getKind() == lltok::LocalVar) {
        NameStr = Lex.getStrVal();
        Lex.Lex();
        if (parseToken(lltok::equal, "expected '=' after instruction name"))
          return true;
      }
  
      switch (parseInstruction(Inst, BB, PFS)) {
      default:
        llvm_unreachable("Unknown parseInstruction result!");
      case InstError: return true;
      case InstNormal:
        BB->getInstList().push_back(Inst);
  
        // With a normal result, we check to see if the instruction is followed by
        // a comma and metadata.
        if (EatIfPresent(lltok::comma))
          if (parseInstructionMetadata(*Inst))
            return true;
        break;
      case InstExtraComma:
        BB->getInstList().push_back(Inst);
  
        // If the instruction parser ate an extra comma at the end of it, it
        // *must* be followed by metadata.
        if (parseInstructionMetadata(*Inst))
          return true;
        break;
      }
  
      // Set the name on the instruction.
      if (PFS.setInstName(NameID, NameStr, NameLoc, Inst))
        return true;
    } while (!Inst->isTerminator());
  
    return false;
  }
  
  //===----------------------------------------------------------------------===//
  // Instruction Parsing.
  //===----------------------------------------------------------------------===//
  
  /// parseInstruction - parse one of the many different instructions.
  ///
  int LLParser::parseInstruction(Instruction *&Inst, BasicBlock *BB,
                                 PerFunctionState &PFS) {
    lltok::Kind Token = Lex.getKind();
    if (Token == lltok::Eof)
      return tokError("found end of file when expecting more instructions");
    LocTy Loc = Lex.getLoc();
    unsigned KeywordVal = Lex.getUIntVal();
    Lex.Lex();  // Eat the keyword.
  
    switch (Token) {
    default:
      return error(Loc, "expected instruction opcode");
    // Terminator Instructions.
    case lltok::kw_unreachable: Inst = new UnreachableInst(Context); return false;
    case lltok::kw_ret:
      return parseRet(Inst, BB, PFS);
    case lltok::kw_br:
      return parseBr(Inst, PFS);
    case lltok::kw_switch:
      return parseSwitch(Inst, PFS);
    case lltok::kw_indirectbr:
      return parseIndirectBr(Inst, PFS);
    case lltok::kw_invoke:
      return parseInvoke(Inst, PFS);
    case lltok::kw_resume:
      return parseResume(Inst, PFS);
    case lltok::kw_cleanupret:
      return parseCleanupRet(Inst, PFS);
    case lltok::kw_catchret:
      return parseCatchRet(Inst, PFS);
    case lltok::kw_catchswitch:
      return parseCatchSwitch(Inst, PFS);
    case lltok::kw_catchpad:
      return parseCatchPad(Inst, PFS);
    case lltok::kw_cleanuppad:
      return parseCleanupPad(Inst, PFS);
    case lltok::kw_callbr:
      return parseCallBr(Inst, PFS);
    // Unary Operators.
    case lltok::kw_fneg: {
      FastMathFlags FMF = EatFastMathFlagsIfPresent();
      int Res = parseUnaryOp(Inst, PFS, KeywordVal, /*IsFP*/ true);
      if (Res != 0)
        return Res;
      if (FMF.any())
        Inst->setFastMathFlags(FMF);
      return false;
    }
    // Binary Operators.
    case lltok::kw_add:
    case lltok::kw_sub:
    case lltok::kw_mul:
    case lltok::kw_shl: {
      bool NUW = EatIfPresent(lltok::kw_nuw);
      bool NSW = EatIfPresent(lltok::kw_nsw);
      if (!NUW) NUW = EatIfPresent(lltok::kw_nuw);
  
      if (parseArithmetic(Inst, PFS, KeywordVal, /*IsFP*/ false))
        return true;
  
      if (NUW) cast<BinaryOperator>(Inst)->setHasNoUnsignedWrap(true);
      if (NSW) cast<BinaryOperator>(Inst)->setHasNoSignedWrap(true);
      return false;
    }
    case lltok::kw_fadd:
    case lltok::kw_fsub:
    case lltok::kw_fmul:
    case lltok::kw_fdiv:
    case lltok::kw_frem: {
      FastMathFlags FMF = EatFastMathFlagsIfPresent();
      int Res = parseArithmetic(Inst, PFS, KeywordVal, /*IsFP*/ true);
      if (Res != 0)
        return Res;
      if (FMF.any())
        Inst->setFastMathFlags(FMF);
      return 0;
    }
  
    case lltok::kw_sdiv:
    case lltok::kw_udiv:
    case lltok::kw_lshr:
    case lltok::kw_ashr: {
      bool Exact = EatIfPresent(lltok::kw_exact);
  
      if (parseArithmetic(Inst, PFS, KeywordVal, /*IsFP*/ false))
        return true;
      if (Exact) cast<BinaryOperator>(Inst)->setIsExact(true);
      return false;
    }
  
    case lltok::kw_urem:
    case lltok::kw_srem:
      return parseArithmetic(Inst, PFS, KeywordVal,
                             /*IsFP*/ false);
    case lltok::kw_and:
    case lltok::kw_or:
    case lltok::kw_xor:
      return parseLogical(Inst, PFS, KeywordVal);
    case lltok::kw_icmp:
      return parseCompare(Inst, PFS, KeywordVal);
    case lltok::kw_fcmp: {
      FastMathFlags FMF = EatFastMathFlagsIfPresent();
      int Res = parseCompare(Inst, PFS, KeywordVal);
      if (Res != 0)
        return Res;
      if (FMF.any())
        Inst->setFastMathFlags(FMF);
      return 0;
    }
  
    // Casts.
    case lltok::kw_trunc:
    case lltok::kw_zext:
    case lltok::kw_sext:
    case lltok::kw_fptrunc:
    case lltok::kw_fpext:
    case lltok::kw_bitcast:
    case lltok::kw_addrspacecast:
    case lltok::kw_uitofp:
    case lltok::kw_sitofp:
    case lltok::kw_fptoui:
    case lltok::kw_fptosi:
    case lltok::kw_inttoptr:
    case lltok::kw_ptrtoint:
      return parseCast(Inst, PFS, KeywordVal);
    // Other.
    case lltok::kw_select: {
      FastMathFlags FMF = EatFastMathFlagsIfPresent();
      int Res = parseSelect(Inst, PFS);
      if (Res != 0)
        return Res;
      if (FMF.any()) {
        if (!isa<FPMathOperator>(Inst))
          return error(Loc, "fast-math-flags specified for select without "
                            "floating-point scalar or vector return type");
        Inst->setFastMathFlags(FMF);
      }
      return 0;
    }
    case lltok::kw_va_arg:
      return parseVAArg(Inst, PFS);
    case lltok::kw_extractelement:
      return parseExtractElement(Inst, PFS);
    case lltok::kw_insertelement:
      return parseInsertElement(Inst, PFS);
    case lltok::kw_shufflevector:
      return parseShuffleVector(Inst, PFS);
    case lltok::kw_phi: {
      FastMathFlags FMF = EatFastMathFlagsIfPresent();
      int Res = parsePHI(Inst, PFS);
      if (Res != 0)
        return Res;
      if (FMF.any()) {
        if (!isa<FPMathOperator>(Inst))
          return error(Loc, "fast-math-flags specified for phi without "
                            "floating-point scalar or vector return type");
        Inst->setFastMathFlags(FMF);
      }
      return 0;
    }
    case lltok::kw_landingpad:
      return parseLandingPad(Inst, PFS);
    case lltok::kw_freeze:
      return parseFreeze(Inst, PFS);
    // Call.
    case lltok::kw_call:
      return parseCall(Inst, PFS, CallInst::TCK_None);
    case lltok::kw_tail:
      return parseCall(Inst, PFS, CallInst::TCK_Tail);
    case lltok::kw_musttail:
      return parseCall(Inst, PFS, CallInst::TCK_MustTail);
    case lltok::kw_notail:
      return parseCall(Inst, PFS, CallInst::TCK_NoTail);
    // Memory.
    case lltok::kw_alloca:
      return parseAlloc(Inst, PFS);
    case lltok::kw_load:
      return parseLoad(Inst, PFS);
    case lltok::kw_store:
      return parseStore(Inst, PFS);
    case lltok::kw_cmpxchg:
      return parseCmpXchg(Inst, PFS);
    case lltok::kw_atomicrmw:
      return parseAtomicRMW(Inst, PFS);
    case lltok::kw_fence:
      return parseFence(Inst, PFS);
    case lltok::kw_getelementptr:
      return parseGetElementPtr(Inst, PFS);
    case lltok::kw_extractvalue:
      return parseExtractValue(Inst, PFS);
    case lltok::kw_insertvalue:
      return parseInsertValue(Inst, PFS);
    }
  }
  
  /// parseCmpPredicate - parse an integer or fp predicate, based on Kind.
  bool LLParser::parseCmpPredicate(unsigned &P, unsigned Opc) {
    if (Opc == Instruction::FCmp) {
      switch (Lex.getKind()) {
      default:
        return tokError("expected fcmp predicate (e.g. 'oeq')");
      case lltok::kw_oeq: P = CmpInst::FCMP_OEQ; break;
      case lltok::kw_one: P = CmpInst::FCMP_ONE; break;
      case lltok::kw_olt: P = CmpInst::FCMP_OLT; break;
      case lltok::kw_ogt: P = CmpInst::FCMP_OGT; break;
      case lltok::kw_ole: P = CmpInst::FCMP_OLE; break;
      case lltok::kw_oge: P = CmpInst::FCMP_OGE; break;
      case lltok::kw_ord: P = CmpInst::FCMP_ORD; break;
      case lltok::kw_uno: P = CmpInst::FCMP_UNO; break;
      case lltok::kw_ueq: P = CmpInst::FCMP_UEQ; break;
      case lltok::kw_une: P = CmpInst::FCMP_UNE; break;
      case lltok::kw_ult: P = CmpInst::FCMP_ULT; break;
      case lltok::kw_ugt: P = CmpInst::FCMP_UGT; break;
      case lltok::kw_ule: P = CmpInst::FCMP_ULE; break;
      case lltok::kw_uge: P = CmpInst::FCMP_UGE; break;
      case lltok::kw_true: P = CmpInst::FCMP_TRUE; break;
      case lltok::kw_false: P = CmpInst::FCMP_FALSE; break;
      }
    } else {
      switch (Lex.getKind()) {
      default:
        return tokError("expected icmp predicate (e.g. 'eq')");
      case lltok::kw_eq:  P = CmpInst::ICMP_EQ; break;
      case lltok::kw_ne:  P = CmpInst::ICMP_NE; break;
      case lltok::kw_slt: P = CmpInst::ICMP_SLT; break;
      case lltok::kw_sgt: P = CmpInst::ICMP_SGT; break;
      case lltok::kw_sle: P = CmpInst::ICMP_SLE; break;
      case lltok::kw_sge: P = CmpInst::ICMP_SGE; break;
      case lltok::kw_ult: P = CmpInst::ICMP_ULT; break;
      case lltok::kw_ugt: P = CmpInst::ICMP_UGT; break;
      case lltok::kw_ule: P = CmpInst::ICMP_ULE; break;
      case lltok::kw_uge: P = CmpInst::ICMP_UGE; break;
      }
    }
    Lex.Lex();
    return false;
  }
  
  //===----------------------------------------------------------------------===//
  // Terminator Instructions.
  //===----------------------------------------------------------------------===//
  
  /// parseRet - parse a return instruction.
  ///   ::= 'ret' void (',' !dbg, !1)*
  ///   ::= 'ret' TypeAndValue (',' !dbg, !1)*
  bool LLParser::parseRet(Instruction *&Inst, BasicBlock *BB,
                          PerFunctionState &PFS) {
    SMLoc TypeLoc = Lex.getLoc();
    Type *Ty = nullptr;
    if (parseType(Ty, true /*void allowed*/))
      return true;
  
    Type *ResType = PFS.getFunction().getReturnType();
  
    if (Ty->isVoidTy()) {
      if (!ResType->isVoidTy())
        return error(TypeLoc, "value doesn't match function result type '" +
                                  getTypeString(ResType) + "'");
  
      Inst = ReturnInst::Create(Context);
      return false;
    }
  
    Value *RV;
    if (parseValue(Ty, RV, PFS))
      return true;
  
    if (ResType != RV->getType())
      return error(TypeLoc, "value doesn't match function result type '" +
                                getTypeString(ResType) + "'");
  
    Inst = ReturnInst::Create(Context, RV);
    return false;
  }
  
  /// parseBr
  ///   ::= 'br' TypeAndValue
  ///   ::= 'br' TypeAndValue ',' TypeAndValue ',' TypeAndValue
  bool LLParser::parseBr(Instruction *&Inst, PerFunctionState &PFS) {
    LocTy Loc, Loc2;
    Value *Op0;
    BasicBlock *Op1, *Op2;
    if (parseTypeAndValue(Op0, Loc, PFS))
      return true;
  
    if (BasicBlock *BB = dyn_cast<BasicBlock>(Op0)) {
      Inst = BranchInst::Create(BB);
      return false;
    }
  
    if (Op0->getType() != Type::getInt1Ty(Context))
      return error(Loc, "branch condition must have 'i1' type");
  
    if (parseToken(lltok::comma, "expected ',' after branch condition") ||
        parseTypeAndBasicBlock(Op1, Loc, PFS) ||
        parseToken(lltok::comma, "expected ',' after true destination") ||
        parseTypeAndBasicBlock(Op2, Loc2, PFS))
      return true;
  
    Inst = BranchInst::Create(Op1, Op2, Op0);
    return false;
  }
  
  /// parseSwitch
  ///  Instruction
  ///    ::= 'switch' TypeAndValue ',' TypeAndValue '[' JumpTable ']'
  ///  JumpTable
  ///    ::= (TypeAndValue ',' TypeAndValue)*
  bool LLParser::parseSwitch(Instruction *&Inst, PerFunctionState &PFS) {
    LocTy CondLoc, BBLoc;
    Value *Cond;
    BasicBlock *DefaultBB;
    if (parseTypeAndValue(Cond, CondLoc, PFS) ||
        parseToken(lltok::comma, "expected ',' after switch condition") ||
        parseTypeAndBasicBlock(DefaultBB, BBLoc, PFS) ||
        parseToken(lltok::lsquare, "expected '[' with switch table"))
      return true;
  
    if (!Cond->getType()->isIntegerTy())
      return error(CondLoc, "switch condition must have integer type");
  
    // parse the jump table pairs.
    SmallPtrSet<Value*, 32> SeenCases;
    SmallVector<std::pair<ConstantInt*, BasicBlock*>, 32> Table;
    while (Lex.getKind() != lltok::rsquare) {
      Value *Constant;
      BasicBlock *DestBB;
  
      if (parseTypeAndValue(Constant, CondLoc, PFS) ||
          parseToken(lltok::comma, "expected ',' after case value") ||
          parseTypeAndBasicBlock(DestBB, PFS))
        return true;
  
      if (!SeenCases.insert(Constant).second)
        return error(CondLoc, "duplicate case value in switch");
      if (!isa<ConstantInt>(Constant))
        return error(CondLoc, "case value is not a constant integer");
  
      Table.push_back(std::make_pair(cast<ConstantInt>(Constant), DestBB));
    }
  
    Lex.Lex();  // Eat the ']'.
  
    SwitchInst *SI = SwitchInst::Create(Cond, DefaultBB, Table.size());
    for (unsigned i = 0, e = Table.size(); i != e; ++i)
      SI->addCase(Table[i].first, Table[i].second);
    Inst = SI;
    return false;
  }
  
  /// parseIndirectBr
  ///  Instruction
  ///    ::= 'indirectbr' TypeAndValue ',' '[' LabelList ']'
  bool LLParser::parseIndirectBr(Instruction *&Inst, PerFunctionState &PFS) {
    LocTy AddrLoc;
    Value *Address;
    if (parseTypeAndValue(Address, AddrLoc, PFS) ||
        parseToken(lltok::comma, "expected ',' after indirectbr address") ||
        parseToken(lltok::lsquare, "expected '[' with indirectbr"))
      return true;
  
    if (!Address->getType()->isPointerTy())
      return error(AddrLoc, "indirectbr address must have pointer type");
  
    // parse the destination list.
    SmallVector<BasicBlock*, 16> DestList;
  
    if (Lex.getKind() != lltok::rsquare) {
      BasicBlock *DestBB;
      if (parseTypeAndBasicBlock(DestBB, PFS))
        return true;
      DestList.push_back(DestBB);
  
      while (EatIfPresent(lltok::comma)) {
        if (parseTypeAndBasicBlock(DestBB, PFS))
          return true;
        DestList.push_back(DestBB);
      }
    }
  
    if (parseToken(lltok::rsquare, "expected ']' at end of block list"))
      return true;
  
    IndirectBrInst *IBI = IndirectBrInst::Create(Address, DestList.size());
    for (unsigned i = 0, e = DestList.size(); i != e; ++i)
      IBI->addDestination(DestList[i]);
    Inst = IBI;
    return false;
  }
  
  /// parseInvoke
  ///   ::= 'invoke' OptionalCallingConv OptionalAttrs Type Value ParamList
  ///       OptionalAttrs 'to' TypeAndValue 'unwind' TypeAndValue
  bool LLParser::parseInvoke(Instruction *&Inst, PerFunctionState &PFS) {
    LocTy CallLoc = Lex.getLoc();
    AttrBuilder RetAttrs, FnAttrs;
    std::vector<unsigned> FwdRefAttrGrps;
    LocTy NoBuiltinLoc;
    unsigned CC;
    unsigned InvokeAddrSpace;
    Type *RetType = nullptr;
    LocTy RetTypeLoc;
    ValID CalleeID;
    SmallVector<ParamInfo, 16> ArgList;
    SmallVector<OperandBundleDef, 2> BundleList;
  
    BasicBlock *NormalBB, *UnwindBB;
    if (parseOptionalCallingConv(CC) || parseOptionalReturnAttrs(RetAttrs) ||
        parseOptionalProgramAddrSpace(InvokeAddrSpace) ||
        parseType(RetType, RetTypeLoc, true /*void allowed*/) ||
        parseValID(CalleeID, &PFS) || parseParameterList(ArgList, PFS) ||
        parseFnAttributeValuePairs(FnAttrs, FwdRefAttrGrps, false,
                                   NoBuiltinLoc) ||
        parseOptionalOperandBundles(BundleList, PFS) ||
        parseToken(lltok::kw_to, "expected 'to' in invoke") ||
        parseTypeAndBasicBlock(NormalBB, PFS) ||
        parseToken(lltok::kw_unwind, "expected 'unwind' in invoke") ||
        parseTypeAndBasicBlock(UnwindBB, PFS))
      return true;
  
    // If RetType is a non-function pointer type, then this is the short syntax
    // for the call, which means that RetType is just the return type.  Infer the
    // rest of the function argument types from the arguments that are present.
    FunctionType *Ty = dyn_cast<FunctionType>(RetType);
    if (!Ty) {
      // Pull out the types of all of the arguments...
      std::vector<Type*> ParamTypes;
      for (unsigned i = 0, e = ArgList.size(); i != e; ++i)
        ParamTypes.push_back(ArgList[i].V->getType());
  
      if (!FunctionType::isValidReturnType(RetType))
        return error(RetTypeLoc, "Invalid result type for LLVM function");
  
      Ty = FunctionType::get(RetType, ParamTypes, false);
    }
  
    CalleeID.FTy = Ty;
  
    // Look up the callee.
    Value *Callee;
    if (convertValIDToValue(PointerType::get(Ty, InvokeAddrSpace), CalleeID,
                            Callee, &PFS))
      return true;
  
    // Set up the Attribute for the function.
    SmallVector<Value *, 8> Args;
    SmallVector<AttributeSet, 8> ArgAttrs;
  
    // Loop through FunctionType's arguments and ensure they are specified
    // correctly.  Also, gather any parameter attributes.
    FunctionType::param_iterator I = Ty->param_begin();
    FunctionType::param_iterator E = Ty->param_end();
    for (unsigned i = 0, e = ArgList.size(); i != e; ++i) {
      Type *ExpectedTy = nullptr;
      if (I != E) {
        ExpectedTy = *I++;
      } else if (!Ty->isVarArg()) {
        return error(ArgList[i].Loc, "too many arguments specified");
      }
  
      if (ExpectedTy && ExpectedTy != ArgList[i].V->getType())
        return error(ArgList[i].Loc, "argument is not of expected type '" +
                                         getTypeString(ExpectedTy) + "'");
      Args.push_back(ArgList[i].V);
      ArgAttrs.push_back(ArgList[i].Attrs);
    }
  
    if (I != E)
      return error(CallLoc, "not enough parameters specified for call");
  
    if (FnAttrs.hasAlignmentAttr())
      return error(CallLoc, "invoke instructions may not have an alignment");
  
    // Finish off the Attribute and check them
    AttributeList PAL =
        AttributeList::get(Context, AttributeSet::get(Context, FnAttrs),
                           AttributeSet::get(Context, RetAttrs), ArgAttrs);
  
    InvokeInst *II =
        InvokeInst::Create(Ty, Callee, NormalBB, UnwindBB, Args, BundleList);
    II->setCallingConv(CC);
    II->setAttributes(PAL);
    ForwardRefAttrGroups[II] = FwdRefAttrGrps;
    Inst = II;
    return false;
  }
  
  /// parseResume
  ///   ::= 'resume' TypeAndValue
  bool LLParser::parseResume(Instruction *&Inst, PerFunctionState &PFS) {
    Value *Exn; LocTy ExnLoc;
    if (parseTypeAndValue(Exn, ExnLoc, PFS))
      return true;
  
    ResumeInst *RI = ResumeInst::Create(Exn);
    Inst = RI;
    return false;
  }
  
  bool LLParser::parseExceptionArgs(SmallVectorImpl<Value *> &Args,
                                    PerFunctionState &PFS) {
    if (parseToken(lltok::lsquare, "expected '[' in catchpad/cleanuppad"))
      return true;
  
    while (Lex.getKind() != lltok::rsquare) {
      // If this isn't the first argument, we need a comma.
      if (!Args.empty() &&
          parseToken(lltok::comma, "expected ',' in argument list"))
        return true;
  
      // parse the argument.
      LocTy ArgLoc;
      Type *ArgTy = nullptr;
      if (parseType(ArgTy, ArgLoc))
        return true;
  
      Value *V;
      if (ArgTy->isMetadataTy()) {
        if (parseMetadataAsValue(V, PFS))
          return true;
      } else {
        if (parseValue(ArgTy, V, PFS))
          return true;
      }
      Args.push_back(V);
    }
  
    Lex.Lex();  // Lex the ']'.
    return false;
  }
  
  /// parseCleanupRet
  ///   ::= 'cleanupret' from Value unwind ('to' 'caller' | TypeAndValue)
  bool LLParser::parseCleanupRet(Instruction *&Inst, PerFunctionState &PFS) {
    Value *CleanupPad = nullptr;
  
    if (parseToken(lltok::kw_from, "expected 'from' after cleanupret"))
      return true;
  
    if (parseValue(Type::getTokenTy(Context), CleanupPad, PFS))
      return true;
  
    if (parseToken(lltok::kw_unwind, "expected 'unwind' in cleanupret"))
      return true;
  
    BasicBlock *UnwindBB = nullptr;
    if (Lex.getKind() == lltok::kw_to) {
      Lex.Lex();
      if (parseToken(lltok::kw_caller, "expected 'caller' in cleanupret"))
        return true;
    } else {
      if (parseTypeAndBasicBlock(UnwindBB, PFS)) {
        return true;
      }
    }
  
    Inst = CleanupReturnInst::Create(CleanupPad, UnwindBB);
    return false;
  }
  
  /// parseCatchRet
  ///   ::= 'catchret' from Parent Value 'to' TypeAndValue
  bool LLParser::parseCatchRet(Instruction *&Inst, PerFunctionState &PFS) {
    Value *CatchPad = nullptr;
  
    if (parseToken(lltok::kw_from, "expected 'from' after catchret"))
      return true;
  
    if (parseValue(Type::getTokenTy(Context), CatchPad, PFS))
      return true;
  
    BasicBlock *BB;
    if (parseToken(lltok::kw_to, "expected 'to' in catchret") ||
        parseTypeAndBasicBlock(BB, PFS))
      return true;
  
    Inst = CatchReturnInst::Create(CatchPad, BB);
    return false;
  }
  
  /// parseCatchSwitch
  ///   ::= 'catchswitch' within Parent
  bool LLParser::parseCatchSwitch(Instruction *&Inst, PerFunctionState &PFS) {
    Value *ParentPad;
  
    if (parseToken(lltok::kw_within, "expected 'within' after catchswitch"))
      return true;
  
    if (Lex.getKind() != lltok::kw_none && Lex.getKind() != lltok::LocalVar &&
        Lex.getKind() != lltok::LocalVarID)
      return tokError("expected scope value for catchswitch");
  
    if (parseValue(Type::getTokenTy(Context), ParentPad, PFS))
      return true;
  
    if (parseToken(lltok::lsquare, "expected '[' with catchswitch labels"))
      return true;
  
    SmallVector<BasicBlock *, 32> Table;
    do {
      BasicBlock *DestBB;
      if (parseTypeAndBasicBlock(DestBB, PFS))
        return true;
      Table.push_back(DestBB);
    } while (EatIfPresent(lltok::comma));
  
    if (parseToken(lltok::rsquare, "expected ']' after catchswitch labels"))
      return true;
  
    if (parseToken(lltok::kw_unwind, "expected 'unwind' after catchswitch scope"))
      return true;
  
    BasicBlock *UnwindBB = nullptr;
    if (EatIfPresent(lltok::kw_to)) {
      if (parseToken(lltok::kw_caller, "expected 'caller' in catchswitch"))
        return true;
    } else {
      if (parseTypeAndBasicBlock(UnwindBB, PFS))
        return true;
    }
  
    auto *CatchSwitch =
        CatchSwitchInst::Create(ParentPad, UnwindBB, Table.size());
    for (BasicBlock *DestBB : Table)
      CatchSwitch->addHandler(DestBB);
    Inst = CatchSwitch;
    return false;
  }
  
  /// parseCatchPad
  ///   ::= 'catchpad' ParamList 'to' TypeAndValue 'unwind' TypeAndValue
  bool LLParser::parseCatchPad(Instruction *&Inst, PerFunctionState &PFS) {
    Value *CatchSwitch = nullptr;
  
    if (parseToken(lltok::kw_within, "expected 'within' after catchpad"))
      return true;
  
    if (Lex.getKind() != lltok::LocalVar && Lex.getKind() != lltok::LocalVarID)
      return tokError("expected scope value for catchpad");
  
    if (parseValue(Type::getTokenTy(Context), CatchSwitch, PFS))
      return true;
  
    SmallVector<Value *, 8> Args;
    if (parseExceptionArgs(Args, PFS))
      return true;
  
    Inst = CatchPadInst::Create(CatchSwitch, Args);
    return false;
  }
  
  /// parseCleanupPad
  ///   ::= 'cleanuppad' within Parent ParamList
  bool LLParser::parseCleanupPad(Instruction *&Inst, PerFunctionState &PFS) {
    Value *ParentPad = nullptr;
  
    if (parseToken(lltok::kw_within, "expected 'within' after cleanuppad"))
      return true;
  
    if (Lex.getKind() != lltok::kw_none && Lex.getKind() != lltok::LocalVar &&
        Lex.getKind() != lltok::LocalVarID)
      return tokError("expected scope value for cleanuppad");
  
    if (parseValue(Type::getTokenTy(Context), ParentPad, PFS))
      return true;
  
    SmallVector<Value *, 8> Args;
    if (parseExceptionArgs(Args, PFS))
      return true;
  
    Inst = CleanupPadInst::Create(ParentPad, Args);
    return false;
  }
  
  //===----------------------------------------------------------------------===//
  // Unary Operators.
  //===----------------------------------------------------------------------===//
  
  /// parseUnaryOp
  ///  ::= UnaryOp TypeAndValue ',' Value
  ///
  /// If IsFP is false, then any integer operand is allowed, if it is true, any fp
  /// operand is allowed.
  bool LLParser::parseUnaryOp(Instruction *&Inst, PerFunctionState &PFS,
                              unsigned Opc, bool IsFP) {
    LocTy Loc; Value *LHS;
    if (parseTypeAndValue(LHS, Loc, PFS))
      return true;
  
    bool Valid = IsFP ? LHS->getType()->isFPOrFPVectorTy()
                      : LHS->getType()->isIntOrIntVectorTy();
  
    if (!Valid)
      return error(Loc, "invalid operand type for instruction");
  
    Inst = UnaryOperator::Create((Instruction::UnaryOps)Opc, LHS);
    return false;
  }
  
  /// parseCallBr
  ///   ::= 'callbr' OptionalCallingConv OptionalAttrs Type Value ParamList
  ///       OptionalAttrs OptionalOperandBundles 'to' TypeAndValue
  ///       '[' LabelList ']'
  bool LLParser::parseCallBr(Instruction *&Inst, PerFunctionState &PFS) {
    LocTy CallLoc = Lex.getLoc();
    AttrBuilder RetAttrs, FnAttrs;
    std::vector<unsigned> FwdRefAttrGrps;
    LocTy NoBuiltinLoc;
    unsigned CC;
    Type *RetType = nullptr;
    LocTy RetTypeLoc;
    ValID CalleeID;
    SmallVector<ParamInfo, 16> ArgList;
    SmallVector<OperandBundleDef, 2> BundleList;
  
    BasicBlock *DefaultDest;
    if (parseOptionalCallingConv(CC) || parseOptionalReturnAttrs(RetAttrs) ||
        parseType(RetType, RetTypeLoc, true /*void allowed*/) ||
        parseValID(CalleeID, &PFS) || parseParameterList(ArgList, PFS) ||
        parseFnAttributeValuePairs(FnAttrs, FwdRefAttrGrps, false,
                                   NoBuiltinLoc) ||
        parseOptionalOperandBundles(BundleList, PFS) ||
        parseToken(lltok::kw_to, "expected 'to' in callbr") ||
        parseTypeAndBasicBlock(DefaultDest, PFS) ||
        parseToken(lltok::lsquare, "expected '[' in callbr"))
      return true;
  
    // parse the destination list.
    SmallVector<BasicBlock *, 16> IndirectDests;
  
    if (Lex.getKind() != lltok::rsquare) {
      BasicBlock *DestBB;
      if (parseTypeAndBasicBlock(DestBB, PFS))
        return true;
      IndirectDests.push_back(DestBB);
  
      while (EatIfPresent(lltok::comma)) {
        if (parseTypeAndBasicBlock(DestBB, PFS))
          return true;
        IndirectDests.push_back(DestBB);
      }
    }
  
    if (parseToken(lltok::rsquare, "expected ']' at end of block list"))
      return true;
  
    // If RetType is a non-function pointer type, then this is the short syntax
    // for the call, which means that RetType is just the return type.  Infer the
    // rest of the function argument types from the arguments that are present.
    FunctionType *Ty = dyn_cast<FunctionType>(RetType);
    if (!Ty) {
      // Pull out the types of all of the arguments...
      std::vector<Type *> ParamTypes;
      for (unsigned i = 0, e = ArgList.size(); i != e; ++i)
        ParamTypes.push_back(ArgList[i].V->getType());
  
      if (!FunctionType::isValidReturnType(RetType))
        return error(RetTypeLoc, "Invalid result type for LLVM function");
  
      Ty = FunctionType::get(RetType, ParamTypes, false);
    }
  
    CalleeID.FTy = Ty;
  
    // Look up the callee.
    Value *Callee;
    if (convertValIDToValue(PointerType::getUnqual(Ty), CalleeID, Callee, &PFS))
      return true;
  
    // Set up the Attribute for the function.
    SmallVector<Value *, 8> Args;
    SmallVector<AttributeSet, 8> ArgAttrs;
  
    // Loop through FunctionType's arguments and ensure they are specified
    // correctly.  Also, gather any parameter attributes.
    FunctionType::param_iterator I = Ty->param_begin();
    FunctionType::param_iterator E = Ty->param_end();
    for (unsigned i = 0, e = ArgList.size(); i != e; ++i) {
      Type *ExpectedTy = nullptr;
      if (I != E) {
        ExpectedTy = *I++;
      } else if (!Ty->isVarArg()) {
        return error(ArgList[i].Loc, "too many arguments specified");
      }
  
      if (ExpectedTy && ExpectedTy != ArgList[i].V->getType())
        return error(ArgList[i].Loc, "argument is not of expected type '" +
                                         getTypeString(ExpectedTy) + "'");
      Args.push_back(ArgList[i].V);
      ArgAttrs.push_back(ArgList[i].Attrs);
    }
  
    if (I != E)
      return error(CallLoc, "not enough parameters specified for call");
  
    if (FnAttrs.hasAlignmentAttr())
      return error(CallLoc, "callbr instructions may not have an alignment");
  
    // Finish off the Attribute and check them
    AttributeList PAL =
        AttributeList::get(Context, AttributeSet::get(Context, FnAttrs),
                           AttributeSet::get(Context, RetAttrs), ArgAttrs);
  
    CallBrInst *CBI =
        CallBrInst::Create(Ty, Callee, DefaultDest, IndirectDests, Args,
                           BundleList);
    CBI->setCallingConv(CC);
    CBI->setAttributes(PAL);
    ForwardRefAttrGroups[CBI] = FwdRefAttrGrps;
    Inst = CBI;
    return false;
  }
  
  //===----------------------------------------------------------------------===//
  // Binary Operators.
  //===----------------------------------------------------------------------===//
  
  /// parseArithmetic
  ///  ::= ArithmeticOps TypeAndValue ',' Value
  ///
  /// If IsFP is false, then any integer operand is allowed, if it is true, any fp
  /// operand is allowed.
  bool LLParser::parseArithmetic(Instruction *&Inst, PerFunctionState &PFS,
                                 unsigned Opc, bool IsFP) {
    LocTy Loc; Value *LHS, *RHS;
    if (parseTypeAndValue(LHS, Loc, PFS) ||
        parseToken(lltok::comma, "expected ',' in arithmetic operation") ||
        parseValue(LHS->getType(), RHS, PFS))
      return true;
  
    bool Valid = IsFP ? LHS->getType()->isFPOrFPVectorTy()
                      : LHS->getType()->isIntOrIntVectorTy();
  
    if (!Valid)
      return error(Loc, "invalid operand type for instruction");
  
    Inst = BinaryOperator::Create((Instruction::BinaryOps)Opc, LHS, RHS);
    return false;
  }
  
  /// parseLogical
  ///  ::= ArithmeticOps TypeAndValue ',' Value {
  bool LLParser::parseLogical(Instruction *&Inst, PerFunctionState &PFS,
                              unsigned Opc) {
    LocTy Loc; Value *LHS, *RHS;
    if (parseTypeAndValue(LHS, Loc, PFS) ||
        parseToken(lltok::comma, "expected ',' in logical operation") ||
        parseValue(LHS->getType(), RHS, PFS))
      return true;
  
    if (!LHS->getType()->isIntOrIntVectorTy())
      return error(Loc,
                   "instruction requires integer or integer vector operands");
  
    Inst = BinaryOperator::Create((Instruction::BinaryOps)Opc, LHS, RHS);
    return false;
  }
  
  /// parseCompare
  ///  ::= 'icmp' IPredicates TypeAndValue ',' Value
  ///  ::= 'fcmp' FPredicates TypeAndValue ',' Value
  bool LLParser::parseCompare(Instruction *&Inst, PerFunctionState &PFS,
                              unsigned Opc) {
    // parse the integer/fp comparison predicate.
    LocTy Loc;
    unsigned Pred;
    Value *LHS, *RHS;
    if (parseCmpPredicate(Pred, Opc) || parseTypeAndValue(LHS, Loc, PFS) ||
        parseToken(lltok::comma, "expected ',' after compare value") ||
        parseValue(LHS->getType(), RHS, PFS))
      return true;
  
    if (Opc == Instruction::FCmp) {
      if (!LHS->getType()->isFPOrFPVectorTy())
        return error(Loc, "fcmp requires floating point operands");
      Inst = new FCmpInst(CmpInst::Predicate(Pred), LHS, RHS);
    } else {
      assert(Opc == Instruction::ICmp && "Unknown opcode for CmpInst!");
      if (!LHS->getType()->isIntOrIntVectorTy() &&
          !LHS->getType()->isPtrOrPtrVectorTy())
        return error(Loc, "icmp requires integer operands");
      Inst = new ICmpInst(CmpInst::Predicate(Pred), LHS, RHS);
    }
    return false;
  }
  
  //===----------------------------------------------------------------------===//
  // Other Instructions.
  //===----------------------------------------------------------------------===//
  
  /// parseCast
  ///   ::= CastOpc TypeAndValue 'to' Type
  bool LLParser::parseCast(Instruction *&Inst, PerFunctionState &PFS,
                           unsigned Opc) {
    LocTy Loc;
    Value *Op;
    Type *DestTy = nullptr;
    if (parseTypeAndValue(Op, Loc, PFS) ||
        parseToken(lltok::kw_to, "expected 'to' after cast value") ||
        parseType(DestTy))
      return true;
  
    if (!CastInst::castIsValid((Instruction::CastOps)Opc, Op, DestTy)) {
      CastInst::castIsValid((Instruction::CastOps)Opc, Op, DestTy);
      return error(Loc, "invalid cast opcode for cast from '" +
                            getTypeString(Op->getType()) + "' to '" +
                            getTypeString(DestTy) + "'");
    }
    Inst = CastInst::Create((Instruction::CastOps)Opc, Op, DestTy);
    return false;
  }
  
  /// parseSelect
  ///   ::= 'select' TypeAndValue ',' TypeAndValue ',' TypeAndValue
  bool LLParser::parseSelect(Instruction *&Inst, PerFunctionState &PFS) {
    LocTy Loc;
    Value *Op0, *Op1, *Op2;
    if (parseTypeAndValue(Op0, Loc, PFS) ||
        parseToken(lltok::comma, "expected ',' after select condition") ||
        parseTypeAndValue(Op1, PFS) ||
        parseToken(lltok::comma, "expected ',' after select value") ||
        parseTypeAndValue(Op2, PFS))
      return true;
  
    if (const char *Reason = SelectInst::areInvalidOperands(Op0, Op1, Op2))
      return error(Loc, Reason);
  
    Inst = SelectInst::Create(Op0, Op1, Op2);
    return false;
  }
  
  /// parseVAArg
  ///   ::= 'va_arg' TypeAndValue ',' Type
  bool LLParser::parseVAArg(Instruction *&Inst, PerFunctionState &PFS) {
    Value *Op;
    Type *EltTy = nullptr;
    LocTy TypeLoc;
    if (parseTypeAndValue(Op, PFS) ||
        parseToken(lltok::comma, "expected ',' after vaarg operand") ||
        parseType(EltTy, TypeLoc))
      return true;
  
    if (!EltTy->isFirstClassType())
      return error(TypeLoc, "va_arg requires operand with first class type");
  
    Inst = new VAArgInst(Op, EltTy);
    return false;
  }
  
  /// parseExtractElement
  ///   ::= 'extractelement' TypeAndValue ',' TypeAndValue
  bool LLParser::parseExtractElement(Instruction *&Inst, PerFunctionState &PFS) {
    LocTy Loc;
    Value *Op0, *Op1;
    if (parseTypeAndValue(Op0, Loc, PFS) ||
        parseToken(lltok::comma, "expected ',' after extract value") ||
        parseTypeAndValue(Op1, PFS))
      return true;
  
    if (!ExtractElementInst::isValidOperands(Op0, Op1))
      return error(Loc, "invalid extractelement operands");
  
    Inst = ExtractElementInst::Create(Op0, Op1);
    return false;
  }
  
  /// parseInsertElement
  ///   ::= 'insertelement' TypeAndValue ',' TypeAndValue ',' TypeAndValue
  bool LLParser::parseInsertElement(Instruction *&Inst, PerFunctionState &PFS) {
    LocTy Loc;
    Value *Op0, *Op1, *Op2;
    if (parseTypeAndValue(Op0, Loc, PFS) ||
        parseToken(lltok::comma, "expected ',' after insertelement value") ||
        parseTypeAndValue(Op1, PFS) ||
        parseToken(lltok::comma, "expected ',' after insertelement value") ||
        parseTypeAndValue(Op2, PFS))
      return true;
  
    if (!InsertElementInst::isValidOperands(Op0, Op1, Op2))
      return error(Loc, "invalid insertelement operands");
  
    Inst = InsertElementInst::Create(Op0, Op1, Op2);
    return false;
  }
  
  /// parseShuffleVector
  ///   ::= 'shufflevector' TypeAndValue ',' TypeAndValue ',' TypeAndValue
  bool LLParser::parseShuffleVector(Instruction *&Inst, PerFunctionState &PFS) {
    LocTy Loc;
    Value *Op0, *Op1, *Op2;
    if (parseTypeAndValue(Op0, Loc, PFS) ||
        parseToken(lltok::comma, "expected ',' after shuffle mask") ||
        parseTypeAndValue(Op1, PFS) ||
        parseToken(lltok::comma, "expected ',' after shuffle value") ||
        parseTypeAndValue(Op2, PFS))
      return true;
  
    if (!ShuffleVectorInst::isValidOperands(Op0, Op1, Op2))
      return error(Loc, "invalid shufflevector operands");
  
    Inst = new ShuffleVectorInst(Op0, Op1, Op2);
    return false;
  }
  
  /// parsePHI
  ///   ::= 'phi' Type '[' Value ',' Value ']' (',' '[' Value ',' Value ']')*
  int LLParser::parsePHI(Instruction *&Inst, PerFunctionState &PFS) {
    Type *Ty = nullptr;  LocTy TypeLoc;
    Value *Op0, *Op1;
  
    if (parseType(Ty, TypeLoc) ||
        parseToken(lltok::lsquare, "expected '[' in phi value list") ||
        parseValue(Ty, Op0, PFS) ||
        parseToken(lltok::comma, "expected ',' after insertelement value") ||
        parseValue(Type::getLabelTy(Context), Op1, PFS) ||
        parseToken(lltok::rsquare, "expected ']' in phi value list"))
      return true;
  
    bool AteExtraComma = false;
    SmallVector<std::pair<Value*, BasicBlock*>, 16> PHIVals;
  
    while (true) {
      PHIVals.push_back(std::make_pair(Op0, cast<BasicBlock>(Op1)));
  
      if (!EatIfPresent(lltok::comma))
        break;
  
      if (Lex.getKind() == lltok::MetadataVar) {
        AteExtraComma = true;
        break;
      }
  
      if (parseToken(lltok::lsquare, "expected '[' in phi value list") ||
          parseValue(Ty, Op0, PFS) ||
          parseToken(lltok::comma, "expected ',' after insertelement value") ||
          parseValue(Type::getLabelTy(Context), Op1, PFS) ||
          parseToken(lltok::rsquare, "expected ']' in phi value list"))
        return true;
    }
  
    if (!Ty->isFirstClassType())
      return error(TypeLoc, "phi node must have first class type");
  
    PHINode *PN = PHINode::Create(Ty, PHIVals.size());
    for (unsigned i = 0, e = PHIVals.size(); i != e; ++i)
      PN->addIncoming(PHIVals[i].first, PHIVals[i].second);
    Inst = PN;
    return AteExtraComma ? InstExtraComma : InstNormal;
  }
  
  /// parseLandingPad
  ///   ::= 'landingpad' Type 'personality' TypeAndValue 'cleanup'? Clause+
  /// Clause
  ///   ::= 'catch' TypeAndValue
  ///   ::= 'filter'
  ///   ::= 'filter' TypeAndValue ( ',' TypeAndValue )*
  bool LLParser::parseLandingPad(Instruction *&Inst, PerFunctionState &PFS) {
    Type *Ty = nullptr; LocTy TyLoc;
  
    if (parseType(Ty, TyLoc))
      return true;
  
    std::unique_ptr<LandingPadInst> LP(LandingPadInst::Create(Ty, 0));
    LP->setCleanup(EatIfPresent(lltok::kw_cleanup));
  
    while (Lex.getKind() == lltok::kw_catch || Lex.getKind() == lltok::kw_filter){
      LandingPadInst::ClauseType CT;
      if (EatIfPresent(lltok::kw_catch))
        CT = LandingPadInst::Catch;
      else if (EatIfPresent(lltok::kw_filter))
        CT = LandingPadInst::Filter;
      else
        return tokError("expected 'catch' or 'filter' clause type");
  
      Value *V;
      LocTy VLoc;
      if (parseTypeAndValue(V, VLoc, PFS))
        return true;
  
      // A 'catch' type expects a non-array constant. A filter clause expects an
      // array constant.
      if (CT == LandingPadInst::Catch) {
        if (isa<ArrayType>(V->getType()))
          error(VLoc, "'catch' clause has an invalid type");
      } else {
        if (!isa<ArrayType>(V->getType()))
          error(VLoc, "'filter' clause has an invalid type");
      }
  
      Constant *CV = dyn_cast<Constant>(V);
      if (!CV)
        return error(VLoc, "clause argument must be a constant");
      LP->addClause(CV);
    }
  
    Inst = LP.release();
    return false;
  }
  
  /// parseFreeze
  ///   ::= 'freeze' Type Value
  bool LLParser::parseFreeze(Instruction *&Inst, PerFunctionState &PFS) {
    LocTy Loc;
    Value *Op;
    if (parseTypeAndValue(Op, Loc, PFS))
      return true;
  
    Inst = new FreezeInst(Op);
    return false;
  }
  
  /// parseCall
  ///   ::= 'call' OptionalFastMathFlags OptionalCallingConv
  ///           OptionalAttrs Type Value ParameterList OptionalAttrs
  ///   ::= 'tail' 'call' OptionalFastMathFlags OptionalCallingConv
  ///           OptionalAttrs Type Value ParameterList OptionalAttrs
  ///   ::= 'musttail' 'call' OptionalFastMathFlags OptionalCallingConv
  ///           OptionalAttrs Type Value ParameterList OptionalAttrs
  ///   ::= 'notail' 'call'  OptionalFastMathFlags OptionalCallingConv
  ///           OptionalAttrs Type Value ParameterList OptionalAttrs
  bool LLParser::parseCall(Instruction *&Inst, PerFunctionState &PFS,
                           CallInst::TailCallKind TCK) {
    AttrBuilder RetAttrs, FnAttrs;
    std::vector<unsigned> FwdRefAttrGrps;
    LocTy BuiltinLoc;
    unsigned CallAddrSpace;
    unsigned CC;
    Type *RetType = nullptr;
    LocTy RetTypeLoc;
    ValID CalleeID;
    SmallVector<ParamInfo, 16> ArgList;
    SmallVector<OperandBundleDef, 2> BundleList;
    LocTy CallLoc = Lex.getLoc();
  
    if (TCK != CallInst::TCK_None &&
        parseToken(lltok::kw_call,
                   "expected 'tail call', 'musttail call', or 'notail call'"))
      return true;
  
    FastMathFlags FMF = EatFastMathFlagsIfPresent();
  
    if (parseOptionalCallingConv(CC) || parseOptionalReturnAttrs(RetAttrs) ||
        parseOptionalProgramAddrSpace(CallAddrSpace) ||
        parseType(RetType, RetTypeLoc, true /*void allowed*/) ||
        parseValID(CalleeID, &PFS) ||
        parseParameterList(ArgList, PFS, TCK == CallInst::TCK_MustTail,
                           PFS.getFunction().isVarArg()) ||
        parseFnAttributeValuePairs(FnAttrs, FwdRefAttrGrps, false, BuiltinLoc) ||
        parseOptionalOperandBundles(BundleList, PFS))
      return true;
  
    // If RetType is a non-function pointer type, then this is the short syntax
    // for the call, which means that RetType is just the return type.  Infer the
    // rest of the function argument types from the arguments that are present.
    FunctionType *Ty = dyn_cast<FunctionType>(RetType);
    if (!Ty) {
      // Pull out the types of all of the arguments...
      std::vector<Type*> ParamTypes;
      for (unsigned i = 0, e = ArgList.size(); i != e; ++i)
        ParamTypes.push_back(ArgList[i].V->getType());
  
      if (!FunctionType::isValidReturnType(RetType))
        return error(RetTypeLoc, "Invalid result type for LLVM function");
  
      Ty = FunctionType::get(RetType, ParamTypes, false);
    }
  
    CalleeID.FTy = Ty;
  
    // Look up the callee.
    Value *Callee;
    if (convertValIDToValue(PointerType::get(Ty, CallAddrSpace), CalleeID, Callee,
                            &PFS))
      return true;
  
    // Set up the Attribute for the function.
    SmallVector<AttributeSet, 8> Attrs;
  
    SmallVector<Value*, 8> Args;
  
    // Loop through FunctionType's arguments and ensure they are specified
    // correctly.  Also, gather any parameter attributes.
    FunctionType::param_iterator I = Ty->param_begin();
    FunctionType::param_iterator E = Ty->param_end();
    for (unsigned i = 0, e = ArgList.size(); i != e; ++i) {
      Type *ExpectedTy = nullptr;
      if (I != E) {
        ExpectedTy = *I++;
      } else if (!Ty->isVarArg()) {
        return error(ArgList[i].Loc, "too many arguments specified");
      }
  
      if (ExpectedTy && ExpectedTy != ArgList[i].V->getType())
        return error(ArgList[i].Loc, "argument is not of expected type '" +
                                         getTypeString(ExpectedTy) + "'");
      Args.push_back(ArgList[i].V);
      Attrs.push_back(ArgList[i].Attrs);
    }
  
    if (I != E)
      return error(CallLoc, "not enough parameters specified for call");
  
    if (FnAttrs.hasAlignmentAttr())
      return error(CallLoc, "call instructions may not have an alignment");
  
    // Finish off the Attribute and check them
    AttributeList PAL =
        AttributeList::get(Context, AttributeSet::get(Context, FnAttrs),
                           AttributeSet::get(Context, RetAttrs), Attrs);
  
    CallInst *CI = CallInst::Create(Ty, Callee, Args, BundleList);
    CI->setTailCallKind(TCK);
    CI->setCallingConv(CC);
    if (FMF.any()) {
      if (!isa<FPMathOperator>(CI)) {
        CI->deleteValue();
        return error(CallLoc, "fast-math-flags specified for call without "
                              "floating-point scalar or vector return type");
      }
      CI->setFastMathFlags(FMF);
    }
    CI->setAttributes(PAL);
    ForwardRefAttrGroups[CI] = FwdRefAttrGrps;
    Inst = CI;
    return false;
  }
  
  //===----------------------------------------------------------------------===//
  // Memory Instructions.
  //===----------------------------------------------------------------------===//
  
  /// parseAlloc
  ///   ::= 'alloca' 'inalloca'? 'swifterror'? Type (',' TypeAndValue)?
  ///       (',' 'align' i32)? (',', 'addrspace(n))?
  int LLParser::parseAlloc(Instruction *&Inst, PerFunctionState &PFS) {
    Value *Size = nullptr;
    LocTy SizeLoc, TyLoc, ASLoc;
    MaybeAlign Alignment;
    unsigned AddrSpace = 0;
    Type *Ty = nullptr;
  
    bool IsInAlloca = EatIfPresent(lltok::kw_inalloca);
    bool IsSwiftError = EatIfPresent(lltok::kw_swifterror);
  
    if (parseType(Ty, TyLoc))
      return true;
  
    if (Ty->isFunctionTy() || !PointerType::isValidElementType(Ty))
      return error(TyLoc, "invalid type for alloca");
  
    bool AteExtraComma = false;
    if (EatIfPresent(lltok::comma)) {
      if (Lex.getKind() == lltok::kw_align) {
        if (parseOptionalAlignment(Alignment))
          return true;
        if (parseOptionalCommaAddrSpace(AddrSpace, ASLoc, AteExtraComma))
          return true;
      } else if (Lex.getKind() == lltok::kw_addrspace) {
        ASLoc = Lex.getLoc();
        if (parseOptionalAddrSpace(AddrSpace))
          return true;
      } else if (Lex.getKind() == lltok::MetadataVar) {
        AteExtraComma = true;
      } else {
        if (parseTypeAndValue(Size, SizeLoc, PFS))
          return true;
        if (EatIfPresent(lltok::comma)) {
          if (Lex.getKind() == lltok::kw_align) {
            if (parseOptionalAlignment(Alignment))
              return true;
            if (parseOptionalCommaAddrSpace(AddrSpace, ASLoc, AteExtraComma))
              return true;
          } else if (Lex.getKind() == lltok::kw_addrspace) {
            ASLoc = Lex.getLoc();
            if (parseOptionalAddrSpace(AddrSpace))
              return true;
          } else if (Lex.getKind() == lltok::MetadataVar) {
            AteExtraComma = true;
          }
        }
      }
    }
  
    if (Size && !Size->getType()->isIntegerTy())
      return error(SizeLoc, "element count must have integer type");
  
    SmallPtrSet<Type *, 4> Visited;
    if (!Alignment && !Ty->isSized(&Visited))
      return error(TyLoc, "Cannot allocate unsized type");
    if (!Alignment)
      Alignment = M->getDataLayout().getPrefTypeAlign(Ty);
    AllocaInst *AI = new AllocaInst(Ty, AddrSpace, Size, *Alignment);
    AI->setUsedWithInAlloca(IsInAlloca);
    AI->setSwiftError(IsSwiftError);
    Inst = AI;
    return AteExtraComma ? InstExtraComma : InstNormal;
  }
  
  /// parseLoad
  ///   ::= 'load' 'volatile'? TypeAndValue (',' 'align' i32)?
  ///   ::= 'load' 'atomic' 'volatile'? TypeAndValue
  ///       'singlethread'? AtomicOrdering (',' 'align' i32)?
  int LLParser::parseLoad(Instruction *&Inst, PerFunctionState &PFS) {
    Value *Val; LocTy Loc;
    MaybeAlign Alignment;
    bool AteExtraComma = false;
    bool isAtomic = false;
    AtomicOrdering Ordering = AtomicOrdering::NotAtomic;
    SyncScope::ID SSID = SyncScope::System;
  
    if (Lex.getKind() == lltok::kw_atomic) {
      isAtomic = true;
      Lex.Lex();
    }
  
    bool isVolatile = false;
    if (Lex.getKind() == lltok::kw_volatile) {
      isVolatile = true;
      Lex.Lex();
    }
  
    Type *Ty;
    LocTy ExplicitTypeLoc = Lex.getLoc();
    if (parseType(Ty) ||
        parseToken(lltok::comma, "expected comma after load's type") ||
        parseTypeAndValue(Val, Loc, PFS) ||
        parseScopeAndOrdering(isAtomic, SSID, Ordering) ||
        parseOptionalCommaAlign(Alignment, AteExtraComma))
      return true;
  
    if (!Val->getType()->isPointerTy() || !Ty->isFirstClassType())
      return error(Loc, "load operand must be a pointer to a first class type");
    if (isAtomic && !Alignment)
      return error(Loc, "atomic load must have explicit non-zero alignment");
    if (Ordering == AtomicOrdering::Release ||
        Ordering == AtomicOrdering::AcquireRelease)
      return error(Loc, "atomic load cannot use Release ordering");
  
    if (!cast<PointerType>(Val->getType())->isOpaqueOrPointeeTypeMatches(Ty)) {
      return error(
          ExplicitTypeLoc,
          typeComparisonErrorMessage(
              "explicit pointee type doesn't match operand's pointee type", Ty,
              cast<PointerType>(Val->getType())->getElementType()));
    }
    SmallPtrSet<Type *, 4> Visited;
    if (!Alignment && !Ty->isSized(&Visited))
      return error(ExplicitTypeLoc, "loading unsized types is not allowed");
    if (!Alignment)
      Alignment = M->getDataLayout().getABITypeAlign(Ty);
    Inst = new LoadInst(Ty, Val, "", isVolatile, *Alignment, Ordering, SSID);
    return AteExtraComma ? InstExtraComma : InstNormal;
  }
  
  /// parseStore
  
  ///   ::= 'store' 'volatile'? TypeAndValue ',' TypeAndValue (',' 'align' i32)?
  ///   ::= 'store' 'atomic' 'volatile'? TypeAndValue ',' TypeAndValue
  ///       'singlethread'? AtomicOrdering (',' 'align' i32)?
  int LLParser::parseStore(Instruction *&Inst, PerFunctionState &PFS) {
    Value *Val, *Ptr; LocTy Loc, PtrLoc;
    MaybeAlign Alignment;
    bool AteExtraComma = false;
    bool isAtomic = false;
    AtomicOrdering Ordering = AtomicOrdering::NotAtomic;
    SyncScope::ID SSID = SyncScope::System;
  
    if (Lex.getKind() == lltok::kw_atomic) {
      isAtomic = true;
      Lex.Lex();
    }
  
    bool isVolatile = false;
    if (Lex.getKind() == lltok::kw_volatile) {
      isVolatile = true;
      Lex.Lex();
    }
  
    if (parseTypeAndValue(Val, Loc, PFS) ||
        parseToken(lltok::comma, "expected ',' after store operand") ||
        parseTypeAndValue(Ptr, PtrLoc, PFS) ||
        parseScopeAndOrdering(isAtomic, SSID, Ordering) ||
        parseOptionalCommaAlign(Alignment, AteExtraComma))
      return true;
  
    if (!Ptr->getType()->isPointerTy())
      return error(PtrLoc, "store operand must be a pointer");
    if (!Val->getType()->isFirstClassType())
      return error(Loc, "store operand must be a first class value");
    if (!cast<PointerType>(Ptr->getType())
             ->isOpaqueOrPointeeTypeMatches(Val->getType()))
      return error(Loc, "stored value and pointer type do not match");
    if (isAtomic && !Alignment)
      return error(Loc, "atomic store must have explicit non-zero alignment");
    if (Ordering == AtomicOrdering::Acquire ||
        Ordering == AtomicOrdering::AcquireRelease)
      return error(Loc, "atomic store cannot use Acquire ordering");
    SmallPtrSet<Type *, 4> Visited;
    if (!Alignment && !Val->getType()->isSized(&Visited))
      return error(Loc, "storing unsized types is not allowed");
    if (!Alignment)
      Alignment = M->getDataLayout().getABITypeAlign(Val->getType());
  
    Inst = new StoreInst(Val, Ptr, isVolatile, *Alignment, Ordering, SSID);
    return AteExtraComma ? InstExtraComma : InstNormal;
  }
  
  /// parseCmpXchg
  ///   ::= 'cmpxchg' 'weak'? 'volatile'? TypeAndValue ',' TypeAndValue ','
  ///       TypeAndValue 'singlethread'? AtomicOrdering AtomicOrdering ','
  ///       'Align'?
  int LLParser::parseCmpXchg(Instruction *&Inst, PerFunctionState &PFS) {
    Value *Ptr, *Cmp, *New; LocTy PtrLoc, CmpLoc, NewLoc;
    bool AteExtraComma = false;
    AtomicOrdering SuccessOrdering = AtomicOrdering::NotAtomic;
    AtomicOrdering FailureOrdering = AtomicOrdering::NotAtomic;
    SyncScope::ID SSID = SyncScope::System;
    bool isVolatile = false;
    bool isWeak = false;
    MaybeAlign Alignment;
  
    if (EatIfPresent(lltok::kw_weak))
      isWeak = true;
  
    if (EatIfPresent(lltok::kw_volatile))
      isVolatile = true;
  
    if (parseTypeAndValue(Ptr, PtrLoc, PFS) ||
        parseToken(lltok::comma, "expected ',' after cmpxchg address") ||
        parseTypeAndValue(Cmp, CmpLoc, PFS) ||
        parseToken(lltok::comma, "expected ',' after cmpxchg cmp operand") ||
        parseTypeAndValue(New, NewLoc, PFS) ||
        parseScopeAndOrdering(true /*Always atomic*/, SSID, SuccessOrdering) ||
        parseOrdering(FailureOrdering) ||
        parseOptionalCommaAlign(Alignment, AteExtraComma))
      return true;
  
    if (!AtomicCmpXchgInst::isValidSuccessOrdering(SuccessOrdering))
      return tokError("invalid cmpxchg success ordering");
    if (!AtomicCmpXchgInst::isValidFailureOrdering(FailureOrdering))
      return tokError("invalid cmpxchg failure ordering");
    if (!Ptr->getType()->isPointerTy())
      return error(PtrLoc, "cmpxchg operand must be a pointer");
    if (!cast<PointerType>(Ptr->getType())
             ->isOpaqueOrPointeeTypeMatches(Cmp->getType()))
      return error(CmpLoc, "compare value and pointer type do not match");
    if (!cast<PointerType>(Ptr->getType())
             ->isOpaqueOrPointeeTypeMatches(New->getType()))
      return error(NewLoc, "new value and pointer type do not match");
    if (Cmp->getType() != New->getType())
      return error(NewLoc, "compare value and new value type do not match");
    if (!New->getType()->isFirstClassType())
      return error(NewLoc, "cmpxchg operand must be a first class value");
  
    const Align DefaultAlignment(
        PFS.getFunction().getParent()->getDataLayout().getTypeStoreSize(
            Cmp->getType()));
  
    AtomicCmpXchgInst *CXI = new AtomicCmpXchgInst(
        Ptr, Cmp, New, Alignment.getValueOr(DefaultAlignment), SuccessOrdering,
        FailureOrdering, SSID);
    CXI->setVolatile(isVolatile);
    CXI->setWeak(isWeak);
  
    Inst = CXI;
    return AteExtraComma ? InstExtraComma : InstNormal;
  }
  
  /// parseAtomicRMW
  ///   ::= 'atomicrmw' 'volatile'? BinOp TypeAndValue ',' TypeAndValue
  ///       'singlethread'? AtomicOrdering
  int LLParser::parseAtomicRMW(Instruction *&Inst, PerFunctionState &PFS) {
    Value *Ptr, *Val; LocTy PtrLoc, ValLoc;
    bool AteExtraComma = false;
    AtomicOrdering Ordering = AtomicOrdering::NotAtomic;
    SyncScope::ID SSID = SyncScope::System;
    bool isVolatile = false;
    bool IsFP = false;
    AtomicRMWInst::BinOp Operation;
    MaybeAlign Alignment;
  
    if (EatIfPresent(lltok::kw_volatile))
      isVolatile = true;
  
    switch (Lex.getKind()) {
    default:
      return tokError("expected binary operation in atomicrmw");
    case lltok::kw_xchg: Operation = AtomicRMWInst::Xchg; break;
    case lltok::kw_add: Operation = AtomicRMWInst::Add; break;
    case lltok::kw_sub: Operation = AtomicRMWInst::Sub; break;
    case lltok::kw_and: Operation = AtomicRMWInst::And; break;
    case lltok::kw_nand: Operation = AtomicRMWInst::Nand; break;
    case lltok::kw_or: Operation = AtomicRMWInst::Or; break;
    case lltok::kw_xor: Operation = AtomicRMWInst::Xor; break;
    case lltok::kw_max: Operation = AtomicRMWInst::Max; break;
    case lltok::kw_min: Operation = AtomicRMWInst::Min; break;
    case lltok::kw_umax: Operation = AtomicRMWInst::UMax; break;
    case lltok::kw_umin: Operation = AtomicRMWInst::UMin; break;
    case lltok::kw_fadd:
      Operation = AtomicRMWInst::FAdd;
      IsFP = true;
      break;
    case lltok::kw_fsub:
      Operation = AtomicRMWInst::FSub;
      IsFP = true;
      break;
    }
    Lex.Lex();  // Eat the operation.
  
    if (parseTypeAndValue(Ptr, PtrLoc, PFS) ||
        parseToken(lltok::comma, "expected ',' after atomicrmw address") ||
        parseTypeAndValue(Val, ValLoc, PFS) ||
        parseScopeAndOrdering(true /*Always atomic*/, SSID, Ordering) ||
        parseOptionalCommaAlign(Alignment, AteExtraComma))
      return true;
  
    if (Ordering == AtomicOrdering::Unordered)
      return tokError("atomicrmw cannot be unordered");
    if (!Ptr->getType()->isPointerTy())
      return error(PtrLoc, "atomicrmw operand must be a pointer");
    if (!cast<PointerType>(Ptr->getType())
             ->isOpaqueOrPointeeTypeMatches(Val->getType()))
      return error(ValLoc, "atomicrmw value and pointer type do not match");
  
    if (Operation == AtomicRMWInst::Xchg) {
      if (!Val->getType()->isIntegerTy() &&
          !Val->getType()->isFloatingPointTy()) {
        return error(ValLoc,
                     "atomicrmw " + AtomicRMWInst::getOperationName(Operation) +
                         " operand must be an integer or floating point type");
      }
    } else if (IsFP) {
      if (!Val->getType()->isFloatingPointTy()) {
        return error(ValLoc, "atomicrmw " +
                                 AtomicRMWInst::getOperationName(Operation) +
                                 " operand must be a floating point type");
      }
    } else {
      if (!Val->getType()->isIntegerTy()) {
        return error(ValLoc, "atomicrmw " +
                                 AtomicRMWInst::getOperationName(Operation) +
                                 " operand must be an integer");
      }
    }
  
    unsigned Size = Val->getType()->getPrimitiveSizeInBits();
    if (Size < 8 || (Size & (Size - 1)))
      return error(ValLoc, "atomicrmw operand must be power-of-two byte-sized"
                           " integer");
    const Align DefaultAlignment(
        PFS.getFunction().getParent()->getDataLayout().getTypeStoreSize(
            Val->getType()));
    AtomicRMWInst *RMWI =
        new AtomicRMWInst(Operation, Ptr, Val,
                          Alignment.getValueOr(DefaultAlignment), Ordering, SSID);
    RMWI->setVolatile(isVolatile);
    Inst = RMWI;
    return AteExtraComma ? InstExtraComma : InstNormal;
  }
  
  /// parseFence
  ///   ::= 'fence' 'singlethread'? AtomicOrdering
  int LLParser::parseFence(Instruction *&Inst, PerFunctionState &PFS) {
    AtomicOrdering Ordering = AtomicOrdering::NotAtomic;
    SyncScope::ID SSID = SyncScope::System;
    if (parseScopeAndOrdering(true /*Always atomic*/, SSID, Ordering))
      return true;
  
    if (Ordering == AtomicOrdering::Unordered)
      return tokError("fence cannot be unordered");
    if (Ordering == AtomicOrdering::Monotonic)
      return tokError("fence cannot be monotonic");
  
    Inst = new FenceInst(Context, Ordering, SSID);
    return InstNormal;
  }
  
  /// parseGetElementPtr
  ///   ::= 'getelementptr' 'inbounds'? TypeAndValue (',' TypeAndValue)*
  int LLParser::parseGetElementPtr(Instruction *&Inst, PerFunctionState &PFS) {
    Value *Ptr = nullptr;
    Value *Val = nullptr;
    LocTy Loc, EltLoc;
  
    bool InBounds = EatIfPresent(lltok::kw_inbounds);
  
    Type *Ty = nullptr;
    LocTy ExplicitTypeLoc = Lex.getLoc();
    if (parseType(Ty) ||
        parseToken(lltok::comma, "expected comma after getelementptr's type") ||
        parseTypeAndValue(Ptr, Loc, PFS))
      return true;
  
    Type *BaseType = Ptr->getType();
    PointerType *BasePointerType = dyn_cast<PointerType>(BaseType->getScalarType());
    if (!BasePointerType)
      return error(Loc, "base of getelementptr must be a pointer");
  
    if (!BasePointerType->isOpaqueOrPointeeTypeMatches(Ty)) {
      return error(
          ExplicitTypeLoc,
          typeComparisonErrorMessage(
              "explicit pointee type doesn't match operand's pointee type", Ty,
              BasePointerType->getElementType()));
    }
  
    SmallVector<Value*, 16> Indices;
    bool AteExtraComma = false;
    // GEP returns a vector of pointers if at least one of parameters is a vector.
    // All vector parameters should have the same vector width.
    ElementCount GEPWidth = BaseType->isVectorTy()
                                ? cast<VectorType>(BaseType)->getElementCount()
                                : ElementCount::getFixed(0);
  
    while (EatIfPresent(lltok::comma)) {
      if (Lex.getKind() == lltok::MetadataVar) {
        AteExtraComma = true;
        break;
      }
      if (parseTypeAndValue(Val, EltLoc, PFS))
        return true;
      if (!Val->getType()->isIntOrIntVectorTy())
        return error(EltLoc, "getelementptr index must be an integer");
  
      if (auto *ValVTy = dyn_cast<VectorType>(Val->getType())) {
        ElementCount ValNumEl = ValVTy->getElementCount();
        if (GEPWidth != ElementCount::getFixed(0) && GEPWidth != ValNumEl)
          return error(
              EltLoc,
              "getelementptr vector index has a wrong number of elements");
        GEPWidth = ValNumEl;
      }
      Indices.push_back(Val);
    }
  
    SmallPtrSet<Type*, 4> Visited;
    if (!Indices.empty() && !Ty->isSized(&Visited))
      return error(Loc, "base element of getelementptr must be sized");
  
    if (!GetElementPtrInst::getIndexedType(Ty, Indices))
      return error(Loc, "invalid getelementptr indices");
    Inst = GetElementPtrInst::Create(Ty, Ptr, Indices);
    if (InBounds)
      cast<GetElementPtrInst>(Inst)->setIsInBounds(true);
    return AteExtraComma ? InstExtraComma : InstNormal;
  }
  
  /// parseExtractValue
  ///   ::= 'extractvalue' TypeAndValue (',' uint32)+
  int LLParser::parseExtractValue(Instruction *&Inst, PerFunctionState &PFS) {
    Value *Val; LocTy Loc;
    SmallVector<unsigned, 4> Indices;
    bool AteExtraComma;
    if (parseTypeAndValue(Val, Loc, PFS) ||
        parseIndexList(Indices, AteExtraComma))
      return true;
  
    if (!Val->getType()->isAggregateType())
      return error(Loc, "extractvalue operand must be aggregate type");
  
    if (!ExtractValueInst::getIndexedType(Val->getType(), Indices))
      return error(Loc, "invalid indices for extractvalue");
    Inst = ExtractValueInst::Create(Val, Indices);
    return AteExtraComma ? InstExtraComma : InstNormal;
  }
  
  /// parseInsertValue
  ///   ::= 'insertvalue' TypeAndValue ',' TypeAndValue (',' uint32)+
  int LLParser::parseInsertValue(Instruction *&Inst, PerFunctionState &PFS) {
    Value *Val0, *Val1; LocTy Loc0, Loc1;
    SmallVector<unsigned, 4> Indices;
    bool AteExtraComma;
    if (parseTypeAndValue(Val0, Loc0, PFS) ||
        parseToken(lltok::comma, "expected comma after insertvalue operand") ||
        parseTypeAndValue(Val1, Loc1, PFS) ||
        parseIndexList(Indices, AteExtraComma))
      return true;
  
    if (!Val0->getType()->isAggregateType())
      return error(Loc0, "insertvalue operand must be aggregate type");
  
    Type *IndexedType = ExtractValueInst::getIndexedType(Val0->getType(), Indices);
    if (!IndexedType)
      return error(Loc0, "invalid indices for insertvalue");
    if (IndexedType != Val1->getType())
      return error(Loc1, "insertvalue operand and field disagree in type: '" +
                             getTypeString(Val1->getType()) + "' instead of '" +
                             getTypeString(IndexedType) + "'");
    Inst = InsertValueInst::Create(Val0, Val1, Indices);
    return AteExtraComma ? InstExtraComma : InstNormal;
  }
  
  //===----------------------------------------------------------------------===//
  // Embedded metadata.
  //===----------------------------------------------------------------------===//
  
  /// parseMDNodeVector
  ///   ::= { Element (',' Element)* }
  /// Element
  ///   ::= 'null' | TypeAndValue
  bool LLParser::parseMDNodeVector(SmallVectorImpl<Metadata *> &Elts) {
    if (parseToken(lltok::lbrace, "expected '{' here"))
      return true;
  
    // Check for an empty list.
    if (EatIfPresent(lltok::rbrace))
      return false;
  
    do {
      // Null is a special case since it is typeless.
      if (EatIfPresent(lltok::kw_null)) {
        Elts.push_back(nullptr);
        continue;
      }
  
      Metadata *MD;
      if (parseMetadata(MD, nullptr))
        return true;
      Elts.push_back(MD);
    } while (EatIfPresent(lltok::comma));
  
    return parseToken(lltok::rbrace, "expected end of metadata node");
  }
  
  //===----------------------------------------------------------------------===//
  // Use-list order directives.
  //===----------------------------------------------------------------------===//
  bool LLParser::sortUseListOrder(Value *V, ArrayRef<unsigned> Indexes,
                                  SMLoc Loc) {
    if (V->use_empty())
      return error(Loc, "value has no uses");
  
    unsigned NumUses = 0;
    SmallDenseMap<const Use *, unsigned, 16> Order;
    for (const Use &U : V->uses()) {
      if (++NumUses > Indexes.size())
        break;
      Order[&U] = Indexes[NumUses - 1];
    }
    if (NumUses < 2)
      return error(Loc, "value only has one use");
    if (Order.size() != Indexes.size() || NumUses > Indexes.size())
      return error(Loc,
                   "wrong number of indexes, expected " + Twine(V->getNumUses()));
  
    V->sortUseList([&](const Use &L, const Use &R) {
      return Order.lookup(&L) < Order.lookup(&R);
    });
    return false;
  }
  
  /// parseUseListOrderIndexes
  ///   ::= '{' uint32 (',' uint32)+ '}'
  bool LLParser::parseUseListOrderIndexes(SmallVectorImpl<unsigned> &Indexes) {
    SMLoc Loc = Lex.getLoc();
    if (parseToken(lltok::lbrace, "expected '{' here"))
      return true;
    if (Lex.getKind() == lltok::rbrace)
      return Lex.Error("expected non-empty list of uselistorder indexes");
  
    // Use Offset, Max, and IsOrdered to check consistency of indexes.  The
    // indexes should be distinct numbers in the range [0, size-1], and should
    // not be in order.
    unsigned Offset = 0;
    unsigned Max = 0;
    bool IsOrdered = true;
    assert(Indexes.empty() && "Expected empty order vector");
    do {
      unsigned Index;
      if (parseUInt32(Index))
        return true;
  
      // Update consistency checks.
      Offset += Index - Indexes.size();
      Max = std::max(Max, Index);
      IsOrdered &= Index == Indexes.size();
  
      Indexes.push_back(Index);
    } while (EatIfPresent(lltok::comma));
  
    if (parseToken(lltok::rbrace, "expected '}' here"))
      return true;
  
    if (Indexes.size() < 2)
      return error(Loc, "expected >= 2 uselistorder indexes");
    if (Offset != 0 || Max >= Indexes.size())
      return error(Loc,
                   "expected distinct uselistorder indexes in range [0, size)");
    if (IsOrdered)
      return error(Loc, "expected uselistorder indexes to change the order");
  
    return false;
  }
  
  /// parseUseListOrder
  ///   ::= 'uselistorder' Type Value ',' UseListOrderIndexes
  bool LLParser::parseUseListOrder(PerFunctionState *PFS) {
    SMLoc Loc = Lex.getLoc();
    if (parseToken(lltok::kw_uselistorder, "expected uselistorder directive"))
      return true;
  
    Value *V;
    SmallVector<unsigned, 16> Indexes;
    if (parseTypeAndValue(V, PFS) ||
        parseToken(lltok::comma, "expected comma in uselistorder directive") ||
        parseUseListOrderIndexes(Indexes))
      return true;
  
    return sortUseListOrder(V, Indexes, Loc);
  }
  
  /// parseUseListOrderBB
  ///   ::= 'uselistorder_bb' @foo ',' %bar ',' UseListOrderIndexes
  bool LLParser::parseUseListOrderBB() {
    assert(Lex.getKind() == lltok::kw_uselistorder_bb);
    SMLoc Loc = Lex.getLoc();
    Lex.Lex();
  
    ValID Fn, Label;
    SmallVector<unsigned, 16> Indexes;
    if (parseValID(Fn, /*PFS=*/nullptr) ||
        parseToken(lltok::comma, "expected comma in uselistorder_bb directive") ||
        parseValID(Label, /*PFS=*/nullptr) ||
        parseToken(lltok::comma, "expected comma in uselistorder_bb directive") ||
        parseUseListOrderIndexes(Indexes))
      return true;
  
    // Check the function.
    GlobalValue *GV;
    if (Fn.Kind == ValID::t_GlobalName)
      GV = M->getNamedValue(Fn.StrVal);
    else if (Fn.Kind == ValID::t_GlobalID)
      GV = Fn.UIntVal < NumberedVals.size() ? NumberedVals[Fn.UIntVal] : nullptr;
    else
      return error(Fn.Loc, "expected function name in uselistorder_bb");
    if (!GV)
      return error(Fn.Loc,
                   "invalid function forward reference in uselistorder_bb");
    auto *F = dyn_cast<Function>(GV);
    if (!F)
      return error(Fn.Loc, "expected function name in uselistorder_bb");
    if (F->isDeclaration())
      return error(Fn.Loc, "invalid declaration in uselistorder_bb");
  
    // Check the basic block.
    if (Label.Kind == ValID::t_LocalID)
      return error(Label.Loc, "invalid numeric label in uselistorder_bb");
    if (Label.Kind != ValID::t_LocalName)
      return error(Label.Loc, "expected basic block name in uselistorder_bb");
    Value *V = F->getValueSymbolTable()->lookup(Label.StrVal);
    if (!V)
      return error(Label.Loc, "invalid basic block in uselistorder_bb");
    if (!isa<BasicBlock>(V))
      return error(Label.Loc, "expected basic block in uselistorder_bb");
  
    return sortUseListOrder(V, Indexes, Loc);
  }
  
  /// ModuleEntry
  ///   ::= 'module' ':' '(' 'path' ':' STRINGCONSTANT ',' 'hash' ':' Hash ')'
  /// Hash ::= '(' UInt32 ',' UInt32 ',' UInt32 ',' UInt32 ',' UInt32 ')'
  bool LLParser::parseModuleEntry(unsigned ID) {
    assert(Lex.getKind() == lltok::kw_module);
    Lex.Lex();
  
    std::string Path;
    if (parseToken(lltok::colon, "expected ':' here") ||
        parseToken(lltok::lparen, "expected '(' here") ||
        parseToken(lltok::kw_path, "expected 'path' here") ||
        parseToken(lltok::colon, "expected ':' here") ||
        parseStringConstant(Path) ||
        parseToken(lltok::comma, "expected ',' here") ||
        parseToken(lltok::kw_hash, "expected 'hash' here") ||
        parseToken(lltok::colon, "expected ':' here") ||
        parseToken(lltok::lparen, "expected '(' here"))
      return true;
  
    ModuleHash Hash;
    if (parseUInt32(Hash[0]) || parseToken(lltok::comma, "expected ',' here") ||
        parseUInt32(Hash[1]) || parseToken(lltok::comma, "expected ',' here") ||
        parseUInt32(Hash[2]) || parseToken(lltok::comma, "expected ',' here") ||
        parseUInt32(Hash[3]) || parseToken(lltok::comma, "expected ',' here") ||
        parseUInt32(Hash[4]))
      return true;
  
    if (parseToken(lltok::rparen, "expected ')' here") ||
        parseToken(lltok::rparen, "expected ')' here"))
      return true;
  
    auto ModuleEntry = Index->addModule(Path, ID, Hash);
    ModuleIdMap[ID] = ModuleEntry->first();
  
    return false;
  }
  
  /// TypeIdEntry
  ///   ::= 'typeid' ':' '(' 'name' ':' STRINGCONSTANT ',' TypeIdSummary ')'
  bool LLParser::parseTypeIdEntry(unsigned ID) {
    assert(Lex.getKind() == lltok::kw_typeid);
    Lex.Lex();
  
    std::string Name;
    if (parseToken(lltok::colon, "expected ':' here") ||
        parseToken(lltok::lparen, "expected '(' here") ||
        parseToken(lltok::kw_name, "expected 'name' here") ||
        parseToken(lltok::colon, "expected ':' here") ||
        parseStringConstant(Name))
      return true;
  
    TypeIdSummary &TIS = Index->getOrInsertTypeIdSummary(Name);
    if (parseToken(lltok::comma, "expected ',' here") ||
        parseTypeIdSummary(TIS) || parseToken(lltok::rparen, "expected ')' here"))
      return true;
  
    // Check if this ID was forward referenced, and if so, update the
    // corresponding GUIDs.
    auto FwdRefTIDs = ForwardRefTypeIds.find(ID);
    if (FwdRefTIDs != ForwardRefTypeIds.end()) {
      for (auto TIDRef : FwdRefTIDs->second) {
        assert(!*TIDRef.first &&
               "Forward referenced type id GUID expected to be 0");
        *TIDRef.first = GlobalValue::getGUID(Name);
      }
      ForwardRefTypeIds.erase(FwdRefTIDs);
    }
  
    return false;
  }
  
  /// TypeIdSummary
  ///   ::= 'summary' ':' '(' TypeTestResolution [',' OptionalWpdResolutions]? ')'
  bool LLParser::parseTypeIdSummary(TypeIdSummary &TIS) {
    if (parseToken(lltok::kw_summary, "expected 'summary' here") ||
        parseToken(lltok::colon, "expected ':' here") ||
        parseToken(lltok::lparen, "expected '(' here") ||
        parseTypeTestResolution(TIS.TTRes))
      return true;
  
    if (EatIfPresent(lltok::comma)) {
      // Expect optional wpdResolutions field
      if (parseOptionalWpdResolutions(TIS.WPDRes))
        return true;
    }
  
    if (parseToken(lltok::rparen, "expected ')' here"))
      return true;
  
    return false;
  }
  
  static ValueInfo EmptyVI =
      ValueInfo(false, (GlobalValueSummaryMapTy::value_type *)-8);
  
  /// TypeIdCompatibleVtableEntry
  ///   ::= 'typeidCompatibleVTable' ':' '(' 'name' ':' STRINGCONSTANT ','
  ///   TypeIdCompatibleVtableInfo
  ///   ')'
  bool LLParser::parseTypeIdCompatibleVtableEntry(unsigned ID) {
    assert(Lex.getKind() == lltok::kw_typeidCompatibleVTable);
    Lex.Lex();
  
    std::string Name;
    if (parseToken(lltok::colon, "expected ':' here") ||
        parseToken(lltok::lparen, "expected '(' here") ||
        parseToken(lltok::kw_name, "expected 'name' here") ||
        parseToken(lltok::colon, "expected ':' here") ||
        parseStringConstant(Name))
      return true;
  
    TypeIdCompatibleVtableInfo &TI =
        Index->getOrInsertTypeIdCompatibleVtableSummary(Name);
    if (parseToken(lltok::comma, "expected ',' here") ||
        parseToken(lltok::kw_summary, "expected 'summary' here") ||
        parseToken(lltok::colon, "expected ':' here") ||
        parseToken(lltok::lparen, "expected '(' here"))
      return true;
  
    IdToIndexMapType IdToIndexMap;
    // parse each call edge
    do {
      uint64_t Offset;
      if (parseToken(lltok::lparen, "expected '(' here") ||
          parseToken(lltok::kw_offset, "expected 'offset' here") ||
          parseToken(lltok::colon, "expected ':' here") || parseUInt64(Offset) ||
          parseToken(lltok::comma, "expected ',' here"))
        return true;
  
      LocTy Loc = Lex.getLoc();
      unsigned GVId;
      ValueInfo VI;
      if (parseGVReference(VI, GVId))
        return true;
  
      // Keep track of the TypeIdCompatibleVtableInfo array index needing a
      // forward reference. We will save the location of the ValueInfo needing an
      // update, but can only do so once the std::vector is finalized.
      if (VI == EmptyVI)
        IdToIndexMap[GVId].push_back(std::make_pair(TI.size(), Loc));
      TI.push_back({Offset, VI});
  
      if (parseToken(lltok::rparen, "expected ')' in call"))
        return true;
    } while (EatIfPresent(lltok::comma));
  
    // Now that the TI vector is finalized, it is safe to save the locations
    // of any forward GV references that need updating later.
    for (auto I : IdToIndexMap) {
      auto &Infos = ForwardRefValueInfos[I.first];
      for (auto P : I.second) {
        assert(TI[P.first].VTableVI == EmptyVI &&
               "Forward referenced ValueInfo expected to be empty");
        Infos.emplace_back(&TI[P.first].VTableVI, P.second);
      }
    }
  
    if (parseToken(lltok::rparen, "expected ')' here") ||
        parseToken(lltok::rparen, "expected ')' here"))
      return true;
  
    // Check if this ID was forward referenced, and if so, update the
    // corresponding GUIDs.
    auto FwdRefTIDs = ForwardRefTypeIds.find(ID);
    if (FwdRefTIDs != ForwardRefTypeIds.end()) {
      for (auto TIDRef : FwdRefTIDs->second) {
        assert(!*TIDRef.first &&
               "Forward referenced type id GUID expected to be 0");
        *TIDRef.first = GlobalValue::getGUID(Name);
      }
      ForwardRefTypeIds.erase(FwdRefTIDs);
    }
  
    return false;
  }
  
  /// TypeTestResolution
  ///   ::= 'typeTestRes' ':' '(' 'kind' ':'
  ///         ( 'unsat' | 'byteArray' | 'inline' | 'single' | 'allOnes' ) ','
  ///         'sizeM1BitWidth' ':' SizeM1BitWidth [',' 'alignLog2' ':' UInt64]?
  ///         [',' 'sizeM1' ':' UInt64]? [',' 'bitMask' ':' UInt8]?
  ///         [',' 'inlinesBits' ':' UInt64]? ')'
  bool LLParser::parseTypeTestResolution(TypeTestResolution &TTRes) {
    if (parseToken(lltok::kw_typeTestRes, "expected 'typeTestRes' here") ||
        parseToken(lltok::colon, "expected ':' here") ||
        parseToken(lltok::lparen, "expected '(' here") ||
        parseToken(lltok::kw_kind, "expected 'kind' here") ||
        parseToken(lltok::colon, "expected ':' here"))
      return true;
  
    switch (Lex.getKind()) {
    case lltok::kw_unknown:
      TTRes.TheKind = TypeTestResolution::Unknown;
      break;
    case lltok::kw_unsat:
      TTRes.TheKind = TypeTestResolution::Unsat;
      break;
    case lltok::kw_byteArray:
      TTRes.TheKind = TypeTestResolution::ByteArray;
      break;
    case lltok::kw_inline:
      TTRes.TheKind = TypeTestResolution::Inline;
      break;
    case lltok::kw_single:
      TTRes.TheKind = TypeTestResolution::Single;
      break;
    case lltok::kw_allOnes:
      TTRes.TheKind = TypeTestResolution::AllOnes;
      break;
    default:
      return error(Lex.getLoc(), "unexpected TypeTestResolution kind");
    }
    Lex.Lex();
  
    if (parseToken(lltok::comma, "expected ',' here") ||
        parseToken(lltok::kw_sizeM1BitWidth, "expected 'sizeM1BitWidth' here") ||
        parseToken(lltok::colon, "expected ':' here") ||
        parseUInt32(TTRes.SizeM1BitWidth))
      return true;
  
    // parse optional fields
    while (EatIfPresent(lltok::comma)) {
      switch (Lex.getKind()) {
      case lltok::kw_alignLog2:
        Lex.Lex();
        if (parseToken(lltok::colon, "expected ':'") ||
            parseUInt64(TTRes.AlignLog2))
          return true;
        break;
      case lltok::kw_sizeM1:
        Lex.Lex();
        if (parseToken(lltok::colon, "expected ':'") || parseUInt64(TTRes.SizeM1))
          return true;
        break;
      case lltok::kw_bitMask: {
        unsigned Val;
        Lex.Lex();
        if (parseToken(lltok::colon, "expected ':'") || parseUInt32(Val))
          return true;
        assert(Val <= 0xff);
        TTRes.BitMask = (uint8_t)Val;
        break;
      }
      case lltok::kw_inlineBits:
        Lex.Lex();
        if (parseToken(lltok::colon, "expected ':'") ||
            parseUInt64(TTRes.InlineBits))
          return true;
        break;
      default:
        return error(Lex.getLoc(), "expected optional TypeTestResolution field");
      }
    }
  
    if (parseToken(lltok::rparen, "expected ')' here"))
      return true;
  
    return false;
  }
  
  /// OptionalWpdResolutions
  ///   ::= 'wpsResolutions' ':' '(' WpdResolution [',' WpdResolution]* ')'
  /// WpdResolution ::= '(' 'offset' ':' UInt64 ',' WpdRes ')'
  bool LLParser::parseOptionalWpdResolutions(
      std::map<uint64_t, WholeProgramDevirtResolution> &WPDResMap) {
    if (parseToken(lltok::kw_wpdResolutions, "expected 'wpdResolutions' here") ||
        parseToken(lltok::colon, "expected ':' here") ||
        parseToken(lltok::lparen, "expected '(' here"))
      return true;
  
    do {
      uint64_t Offset;
      WholeProgramDevirtResolution WPDRes;
      if (parseToken(lltok::lparen, "expected '(' here") ||
          parseToken(lltok::kw_offset, "expected 'offset' here") ||
          parseToken(lltok::colon, "expected ':' here") || parseUInt64(Offset) ||
          parseToken(lltok::comma, "expected ',' here") || parseWpdRes(WPDRes) ||
          parseToken(lltok::rparen, "expected ')' here"))
        return true;
      WPDResMap[Offset] = WPDRes;
    } while (EatIfPresent(lltok::comma));
  
    if (parseToken(lltok::rparen, "expected ')' here"))
      return true;
  
    return false;
  }
  
  /// WpdRes
  ///   ::= 'wpdRes' ':' '(' 'kind' ':' 'indir'
  ///         [',' OptionalResByArg]? ')'
  ///   ::= 'wpdRes' ':' '(' 'kind' ':' 'singleImpl'
  ///         ',' 'singleImplName' ':' STRINGCONSTANT ','
  ///         [',' OptionalResByArg]? ')'
  ///   ::= 'wpdRes' ':' '(' 'kind' ':' 'branchFunnel'
  ///         [',' OptionalResByArg]? ')'
  bool LLParser::parseWpdRes(WholeProgramDevirtResolution &WPDRes) {
    if (parseToken(lltok::kw_wpdRes, "expected 'wpdRes' here") ||
        parseToken(lltok::colon, "expected ':' here") ||
        parseToken(lltok::lparen, "expected '(' here") ||
        parseToken(lltok::kw_kind, "expected 'kind' here") ||
        parseToken(lltok::colon, "expected ':' here"))
      return true;
  
    switch (Lex.getKind()) {
    case lltok::kw_indir:
      WPDRes.TheKind = WholeProgramDevirtResolution::Indir;
      break;
    case lltok::kw_singleImpl:
      WPDRes.TheKind = WholeProgramDevirtResolution::SingleImpl;
      break;
    case lltok::kw_branchFunnel:
      WPDRes.TheKind = WholeProgramDevirtResolution::BranchFunnel;
      break;
    default:
      return error(Lex.getLoc(), "unexpected WholeProgramDevirtResolution kind");
    }
    Lex.Lex();
  
    // parse optional fields
    while (EatIfPresent(lltok::comma)) {
      switch (Lex.getKind()) {
      case lltok::kw_singleImplName:
        Lex.Lex();
        if (parseToken(lltok::colon, "expected ':' here") ||
            parseStringConstant(WPDRes.SingleImplName))
          return true;
        break;
      case lltok::kw_resByArg:
        if (parseOptionalResByArg(WPDRes.ResByArg))
          return true;
        break;
      default:
        return error(Lex.getLoc(),
                     "expected optional WholeProgramDevirtResolution field");
      }
    }
  
    if (parseToken(lltok::rparen, "expected ')' here"))
      return true;
  
    return false;
  }
  
  /// OptionalResByArg
  ///   ::= 'wpdRes' ':' '(' ResByArg[, ResByArg]* ')'
  /// ResByArg ::= Args ',' 'byArg' ':' '(' 'kind' ':'
  ///                ( 'indir' | 'uniformRetVal' | 'UniqueRetVal' |
  ///                  'virtualConstProp' )
  ///                [',' 'info' ':' UInt64]? [',' 'byte' ':' UInt32]?
  ///                [',' 'bit' ':' UInt32]? ')'
  bool LLParser::parseOptionalResByArg(
      std::map<std::vector<uint64_t>, WholeProgramDevirtResolution::ByArg>
          &ResByArg) {
    if (parseToken(lltok::kw_resByArg, "expected 'resByArg' here") ||
        parseToken(lltok::colon, "expected ':' here") ||
        parseToken(lltok::lparen, "expected '(' here"))
      return true;
  
    do {
      std::vector<uint64_t> Args;
      if (parseArgs(Args) || parseToken(lltok::comma, "expected ',' here") ||
          parseToken(lltok::kw_byArg, "expected 'byArg here") ||
          parseToken(lltok::colon, "expected ':' here") ||
          parseToken(lltok::lparen, "expected '(' here") ||
          parseToken(lltok::kw_kind, "expected 'kind' here") ||
          parseToken(lltok::colon, "expected ':' here"))
        return true;
  
      WholeProgramDevirtResolution::ByArg ByArg;
      switch (Lex.getKind()) {
      case lltok::kw_indir:
        ByArg.TheKind = WholeProgramDevirtResolution::ByArg::Indir;
        break;
      case lltok::kw_uniformRetVal:
        ByArg.TheKind = WholeProgramDevirtResolution::ByArg::UniformRetVal;
        break;
      case lltok::kw_uniqueRetVal:
        ByArg.TheKind = WholeProgramDevirtResolution::ByArg::UniqueRetVal;
        break;
      case lltok::kw_virtualConstProp:
        ByArg.TheKind = WholeProgramDevirtResolution::ByArg::VirtualConstProp;
        break;
      default:
        return error(Lex.getLoc(),
                     "unexpected WholeProgramDevirtResolution::ByArg kind");
      }
      Lex.Lex();
  
      // parse optional fields
      while (EatIfPresent(lltok::comma)) {
        switch (Lex.getKind()) {
        case lltok::kw_info:
          Lex.Lex();
          if (parseToken(lltok::colon, "expected ':' here") ||
              parseUInt64(ByArg.Info))
            return true;
          break;
        case lltok::kw_byte:
          Lex.Lex();
          if (parseToken(lltok::colon, "expected ':' here") ||
              parseUInt32(ByArg.Byte))
            return true;
          break;
        case lltok::kw_bit:
          Lex.Lex();
          if (parseToken(lltok::colon, "expected ':' here") ||
              parseUInt32(ByArg.Bit))
            return true;
          break;
        default:
          return error(Lex.getLoc(),
                       "expected optional whole program devirt field");
        }
      }
  
      if (parseToken(lltok::rparen, "expected ')' here"))
        return true;
  
      ResByArg[Args] = ByArg;
    } while (EatIfPresent(lltok::comma));
  
    if (parseToken(lltok::rparen, "expected ')' here"))
      return true;
  
    return false;
  }
  
  /// OptionalResByArg
  ///   ::= 'args' ':' '(' UInt64[, UInt64]* ')'
  bool LLParser::parseArgs(std::vector<uint64_t> &Args) {
    if (parseToken(lltok::kw_args, "expected 'args' here") ||
        parseToken(lltok::colon, "expected ':' here") ||
        parseToken(lltok::lparen, "expected '(' here"))
      return true;
  
    do {
      uint64_t Val;
      if (parseUInt64(Val))
        return true;
      Args.push_back(Val);
    } while (EatIfPresent(lltok::comma));
  
    if (parseToken(lltok::rparen, "expected ')' here"))
      return true;
  
    return false;
  }
  
  static const auto FwdVIRef = (GlobalValueSummaryMapTy::value_type *)-8;
  
  static void resolveFwdRef(ValueInfo *Fwd, ValueInfo &Resolved) {
    bool ReadOnly = Fwd->isReadOnly();
    bool WriteOnly = Fwd->isWriteOnly();
    assert(!(ReadOnly && WriteOnly));
    *Fwd = Resolved;
    if (ReadOnly)
      Fwd->setReadOnly();
    if (WriteOnly)
      Fwd->setWriteOnly();
  }
  
  /// Stores the given Name/GUID and associated summary into the Index.
  /// Also updates any forward references to the associated entry ID.
  void LLParser::addGlobalValueToIndex(
      std::string Name, GlobalValue::GUID GUID, GlobalValue::LinkageTypes Linkage,
      unsigned ID, std::unique_ptr<GlobalValueSummary> Summary) {
    // First create the ValueInfo utilizing the Name or GUID.
    ValueInfo VI;
    if (GUID != 0) {
      assert(Name.empty());
      VI = Index->getOrInsertValueInfo(GUID);
    } else {
      assert(!Name.empty());
      if (M) {
        auto *GV = M->getNamedValue(Name);
        assert(GV);
        VI = Index->getOrInsertValueInfo(GV);
      } else {
        assert(
            (!GlobalValue::isLocalLinkage(Linkage) || !SourceFileName.empty()) &&
            "Need a source_filename to compute GUID for local");
        GUID = GlobalValue::getGUID(
            GlobalValue::getGlobalIdentifier(Name, Linkage, SourceFileName));
        VI = Index->getOrInsertValueInfo(GUID, Index->saveString(Name));
      }
    }
  
    // Resolve forward references from calls/refs
    auto FwdRefVIs = ForwardRefValueInfos.find(ID);
    if (FwdRefVIs != ForwardRefValueInfos.end()) {
      for (auto VIRef : FwdRefVIs->second) {
        assert(VIRef.first->getRef() == FwdVIRef &&
               "Forward referenced ValueInfo expected to be empty");
        resolveFwdRef(VIRef.first, VI);
      }
      ForwardRefValueInfos.erase(FwdRefVIs);
    }
  
    // Resolve forward references from aliases
    auto FwdRefAliasees = ForwardRefAliasees.find(ID);
    if (FwdRefAliasees != ForwardRefAliasees.end()) {
      for (auto AliaseeRef : FwdRefAliasees->second) {
        assert(!AliaseeRef.first->hasAliasee() &&
               "Forward referencing alias already has aliasee");
        assert(Summary && "Aliasee must be a definition");
        AliaseeRef.first->setAliasee(VI, Summary.get());
      }
      ForwardRefAliasees.erase(FwdRefAliasees);
    }
  
    // Add the summary if one was provided.
    if (Summary)
      Index->addGlobalValueSummary(VI, std::move(Summary));
  
    // Save the associated ValueInfo for use in later references by ID.
    if (ID == NumberedValueInfos.size())
      NumberedValueInfos.push_back(VI);
    else {
      // Handle non-continuous numbers (to make test simplification easier).
      if (ID > NumberedValueInfos.size())
        NumberedValueInfos.resize(ID + 1);
      NumberedValueInfos[ID] = VI;
    }
  }
  
  /// parseSummaryIndexFlags
  ///   ::= 'flags' ':' UInt64
  bool LLParser::parseSummaryIndexFlags() {
    assert(Lex.getKind() == lltok::kw_flags);
    Lex.Lex();
  
    if (parseToken(lltok::colon, "expected ':' here"))
      return true;
    uint64_t Flags;
    if (parseUInt64(Flags))
      return true;
    if (Index)
      Index->setFlags(Flags);
    return false;
  }
  
  /// parseBlockCount
  ///   ::= 'blockcount' ':' UInt64
  bool LLParser::parseBlockCount() {
    assert(Lex.getKind() == lltok::kw_blockcount);
    Lex.Lex();
  
    if (parseToken(lltok::colon, "expected ':' here"))
      return true;
    uint64_t BlockCount;
    if (parseUInt64(BlockCount))
      return true;
    if (Index)
      Index->setBlockCount(BlockCount);
    return false;
  }
  
  /// parseGVEntry
  ///   ::= 'gv' ':' '(' ('name' ':' STRINGCONSTANT | 'guid' ':' UInt64)
  ///         [',' 'summaries' ':' Summary[',' Summary]* ]? ')'
  /// Summary ::= '(' (FunctionSummary | VariableSummary | AliasSummary) ')'
  bool LLParser::parseGVEntry(unsigned ID) {
    assert(Lex.getKind() == lltok::kw_gv);
    Lex.Lex();
  
    if (parseToken(lltok::colon, "expected ':' here") ||
        parseToken(lltok::lparen, "expected '(' here"))
      return true;
  
    std::string Name;
    GlobalValue::GUID GUID = 0;
    switch (Lex.getKind()) {
    case lltok::kw_name:
      Lex.Lex();
      if (parseToken(lltok::colon, "expected ':' here") ||
          parseStringConstant(Name))
        return true;
      // Can't create GUID/ValueInfo until we have the linkage.
      break;
    case lltok::kw_guid:
      Lex.Lex();
      if (parseToken(lltok::colon, "expected ':' here") || parseUInt64(GUID))
        return true;
      break;
    default:
      return error(Lex.getLoc(), "expected name or guid tag");
    }
  
    if (!EatIfPresent(lltok::comma)) {
      // No summaries. Wrap up.
      if (parseToken(lltok::rparen, "expected ')' here"))
        return true;
      // This was created for a call to an external or indirect target.
      // A GUID with no summary came from a VALUE_GUID record, dummy GUID
      // created for indirect calls with VP. A Name with no GUID came from
      // an external definition. We pass ExternalLinkage since that is only
      // used when the GUID must be computed from Name, and in that case
      // the symbol must have external linkage.
      addGlobalValueToIndex(Name, GUID, GlobalValue::ExternalLinkage, ID,
                            nullptr);
      return false;
    }
  
    // Have a list of summaries
    if (parseToken(lltok::kw_summaries, "expected 'summaries' here") ||
        parseToken(lltok::colon, "expected ':' here") ||
        parseToken(lltok::lparen, "expected '(' here"))
      return true;
    do {
      switch (Lex.getKind()) {
      case lltok::kw_function:
        if (parseFunctionSummary(Name, GUID, ID))
          return true;
        break;
      case lltok::kw_variable:
        if (parseVariableSummary(Name, GUID, ID))
          return true;
        break;
      case lltok::kw_alias:
        if (parseAliasSummary(Name, GUID, ID))
          return true;
        break;
      default:
        return error(Lex.getLoc(), "expected summary type");
      }
    } while (EatIfPresent(lltok::comma));
  
    if (parseToken(lltok::rparen, "expected ')' here") ||
        parseToken(lltok::rparen, "expected ')' here"))
      return true;
  
    return false;
  }
  
  /// FunctionSummary
  ///   ::= 'function' ':' '(' 'module' ':' ModuleReference ',' GVFlags
  ///         ',' 'insts' ':' UInt32 [',' OptionalFFlags]? [',' OptionalCalls]?
  ///         [',' OptionalTypeIdInfo]? [',' OptionalParamAccesses]?
  ///         [',' OptionalRefs]? ')'
  bool LLParser::parseFunctionSummary(std::string Name, GlobalValue::GUID GUID,
                                      unsigned ID) {
    assert(Lex.getKind() == lltok::kw_function);
    Lex.Lex();
  
    StringRef ModulePath;
    GlobalValueSummary::GVFlags GVFlags = GlobalValueSummary::GVFlags(
        GlobalValue::ExternalLinkage, GlobalValue::DefaultVisibility,
        /*NotEligibleToImport=*/false,
        /*Live=*/false, /*IsLocal=*/false, /*CanAutoHide=*/false);
    unsigned InstCount;
    std::vector<FunctionSummary::EdgeTy> Calls;
    FunctionSummary::TypeIdInfo TypeIdInfo;
    std::vector<FunctionSummary::ParamAccess> ParamAccesses;
    std::vector<ValueInfo> Refs;
    // Default is all-zeros (conservative values).
    FunctionSummary::FFlags FFlags = {};
    if (parseToken(lltok::colon, "expected ':' here") ||
        parseToken(lltok::lparen, "expected '(' here") ||
        parseModuleReference(ModulePath) ||
        parseToken(lltok::comma, "expected ',' here") || parseGVFlags(GVFlags) ||
        parseToken(lltok::comma, "expected ',' here") ||
        parseToken(lltok::kw_insts, "expected 'insts' here") ||
        parseToken(lltok::colon, "expected ':' here") || parseUInt32(InstCount))
      return true;
  
    // parse optional fields
    while (EatIfPresent(lltok::comma)) {
      switch (Lex.getKind()) {
      case lltok::kw_funcFlags:
        if (parseOptionalFFlags(FFlags))
          return true;
        break;
      case lltok::kw_calls:
        if (parseOptionalCalls(Calls))
          return true;
        break;
      case lltok::kw_typeIdInfo:
        if (parseOptionalTypeIdInfo(TypeIdInfo))
          return true;
        break;
      case lltok::kw_refs:
        if (parseOptionalRefs(Refs))
          return true;
        break;
      case lltok::kw_params:
        if (parseOptionalParamAccesses(ParamAccesses))
          return true;
        break;
      default:
        return error(Lex.getLoc(), "expected optional function summary field");
      }
    }
  
    if (parseToken(lltok::rparen, "expected ')' here"))
      return true;
  
    auto FS = std::make_unique<FunctionSummary>(
        GVFlags, InstCount, FFlags, /*EntryCount=*/0, std::move(Refs),
        std::move(Calls), std::move(TypeIdInfo.TypeTests),
        std::move(TypeIdInfo.TypeTestAssumeVCalls),
        std::move(TypeIdInfo.TypeCheckedLoadVCalls),
        std::move(TypeIdInfo.TypeTestAssumeConstVCalls),
        std::move(TypeIdInfo.TypeCheckedLoadConstVCalls),
        std::move(ParamAccesses));
  
    FS->setModulePath(ModulePath);
  
    addGlobalValueToIndex(Name, GUID, (GlobalValue::LinkageTypes)GVFlags.Linkage,
                          ID, std::move(FS));
  
    return false;
  }
  
  /// VariableSummary
  ///   ::= 'variable' ':' '(' 'module' ':' ModuleReference ',' GVFlags
  ///         [',' OptionalRefs]? ')'
  bool LLParser::parseVariableSummary(std::string Name, GlobalValue::GUID GUID,
                                      unsigned ID) {
    assert(Lex.getKind() == lltok::kw_variable);
    Lex.Lex();
  
    StringRef ModulePath;
    GlobalValueSummary::GVFlags GVFlags = GlobalValueSummary::GVFlags(
        GlobalValue::ExternalLinkage, GlobalValue::DefaultVisibility,
        /*NotEligibleToImport=*/false,
        /*Live=*/false, /*IsLocal=*/false, /*CanAutoHide=*/false);
    GlobalVarSummary::GVarFlags GVarFlags(/*ReadOnly*/ false,
                                          /* WriteOnly */ false,
                                          /* Constant */ false,
                                          GlobalObject::VCallVisibilityPublic);
    std::vector<ValueInfo> Refs;
    VTableFuncList VTableFuncs;
    if (parseToken(lltok::colon, "expected ':' here") ||
        parseToken(lltok::lparen, "expected '(' here") ||
        parseModuleReference(ModulePath) ||
        parseToken(lltok::comma, "expected ',' here") || parseGVFlags(GVFlags) ||
        parseToken(lltok::comma, "expected ',' here") ||
        parseGVarFlags(GVarFlags))
      return true;
  
    // parse optional fields
    while (EatIfPresent(lltok::comma)) {
      switch (Lex.getKind()) {
      case lltok::kw_vTableFuncs:
        if (parseOptionalVTableFuncs(VTableFuncs))
          return true;
        break;
      case lltok::kw_refs:
        if (parseOptionalRefs(Refs))
          return true;
        break;
      default:
        return error(Lex.getLoc(), "expected optional variable summary field");
      }
    }
  
    if (parseToken(lltok::rparen, "expected ')' here"))
      return true;
  
    auto GS =
        std::make_unique<GlobalVarSummary>(GVFlags, GVarFlags, std::move(Refs));
  
    GS->setModulePath(ModulePath);
    GS->setVTableFuncs(std::move(VTableFuncs));
  
    addGlobalValueToIndex(Name, GUID, (GlobalValue::LinkageTypes)GVFlags.Linkage,
                          ID, std::move(GS));
  
    return false;
  }
  
  /// AliasSummary
  ///   ::= 'alias' ':' '(' 'module' ':' ModuleReference ',' GVFlags ','
  ///         'aliasee' ':' GVReference ')'
  bool LLParser::parseAliasSummary(std::string Name, GlobalValue::GUID GUID,
                                   unsigned ID) {
    assert(Lex.getKind() == lltok::kw_alias);
    LocTy Loc = Lex.getLoc();
    Lex.Lex();
  
    StringRef ModulePath;
    GlobalValueSummary::GVFlags GVFlags = GlobalValueSummary::GVFlags(
        GlobalValue::ExternalLinkage, GlobalValue::DefaultVisibility,
        /*NotEligibleToImport=*/false,
        /*Live=*/false, /*IsLocal=*/false, /*CanAutoHide=*/false);
    if (parseToken(lltok::colon, "expected ':' here") ||
        parseToken(lltok::lparen, "expected '(' here") ||
        parseModuleReference(ModulePath) ||
        parseToken(lltok::comma, "expected ',' here") || parseGVFlags(GVFlags) ||
        parseToken(lltok::comma, "expected ',' here") ||
        parseToken(lltok::kw_aliasee, "expected 'aliasee' here") ||
        parseToken(lltok::colon, "expected ':' here"))
      return true;
  
    ValueInfo AliaseeVI;
    unsigned GVId;
    if (parseGVReference(AliaseeVI, GVId))
      return true;
  
    if (parseToken(lltok::rparen, "expected ')' here"))
      return true;
  
    auto AS = std::make_unique<AliasSummary>(GVFlags);
  
    AS->setModulePath(ModulePath);
  
    // Record forward reference if the aliasee is not parsed yet.
    if (AliaseeVI.getRef() == FwdVIRef) {
      ForwardRefAliasees[GVId].emplace_back(AS.get(), Loc);
    } else {
      auto Summary = Index->findSummaryInModule(AliaseeVI, ModulePath);
      assert(Summary && "Aliasee must be a definition");
      AS->setAliasee(AliaseeVI, Summary);
    }
  
    addGlobalValueToIndex(Name, GUID, (GlobalValue::LinkageTypes)GVFlags.Linkage,
                          ID, std::move(AS));
  
    return false;
  }
  
  /// Flag
  ///   ::= [0|1]
  bool LLParser::parseFlag(unsigned &Val) {
    if (Lex.getKind() != lltok::APSInt || Lex.getAPSIntVal().isSigned())
      return tokError("expected integer");
    Val = (unsigned)Lex.getAPSIntVal().getBoolValue();
    Lex.Lex();
    return false;
  }
  
  /// OptionalFFlags
  ///   := 'funcFlags' ':' '(' ['readNone' ':' Flag]?
  ///        [',' 'readOnly' ':' Flag]? [',' 'noRecurse' ':' Flag]?
  ///        [',' 'returnDoesNotAlias' ':' Flag]? ')'
  ///        [',' 'noInline' ':' Flag]? ')'
  ///        [',' 'alwaysInline' ':' Flag]? ')'
  ///        [',' 'noUnwind' ':' Flag]? ')'
  ///        [',' 'mayThrow' ':' Flag]? ')'
  ///        [',' 'hasUnknownCall' ':' Flag]? ')'
  
  bool LLParser::parseOptionalFFlags(FunctionSummary::FFlags &FFlags) {
    assert(Lex.getKind() == lltok::kw_funcFlags);
    Lex.Lex();
  
    if (parseToken(lltok::colon, "expected ':' in funcFlags") ||
        parseToken(lltok::lparen, "expected '(' in funcFlags"))
      return true;
  
    do {
      unsigned Val = 0;
      switch (Lex.getKind()) {
      case lltok::kw_readNone:
        Lex.Lex();
        if (parseToken(lltok::colon, "expected ':'") || parseFlag(Val))
          return true;
        FFlags.ReadNone = Val;
        break;
      case lltok::kw_readOnly:
        Lex.Lex();
        if (parseToken(lltok::colon, "expected ':'") || parseFlag(Val))
          return true;
        FFlags.ReadOnly = Val;
        break;
      case lltok::kw_noRecurse:
        Lex.Lex();
        if (parseToken(lltok::colon, "expected ':'") || parseFlag(Val))
          return true;
        FFlags.NoRecurse = Val;
        break;
      case lltok::kw_returnDoesNotAlias:
        Lex.Lex();
        if (parseToken(lltok::colon, "expected ':'") || parseFlag(Val))
          return true;
        FFlags.ReturnDoesNotAlias = Val;
        break;
      case lltok::kw_noInline:
        Lex.Lex();
        if (parseToken(lltok::colon, "expected ':'") || parseFlag(Val))
          return true;
        FFlags.NoInline = Val;
        break;
      case lltok::kw_alwaysInline:
        Lex.Lex();
        if (parseToken(lltok::colon, "expected ':'") || parseFlag(Val))
          return true;
        FFlags.AlwaysInline = Val;
        break;
      case lltok::kw_noUnwind:
        Lex.Lex();
        if (parseToken(lltok::colon, "expected ':'") || parseFlag(Val))
          return true;
        FFlags.NoUnwind = Val;
        break;
      case lltok::kw_mayThrow:
        Lex.Lex();
        if (parseToken(lltok::colon, "expected ':'") || parseFlag(Val))
          return true;
        FFlags.MayThrow = Val;
        break;
      case lltok::kw_hasUnknownCall:
        Lex.Lex();
        if (parseToken(lltok::colon, "expected ':'") || parseFlag(Val))
          return true;
        FFlags.HasUnknownCall = Val;
        break;
      default:
        return error(Lex.getLoc(), "expected function flag type");
      }
    } while (EatIfPresent(lltok::comma));
  
    if (parseToken(lltok::rparen, "expected ')' in funcFlags"))
      return true;
  
    return false;
  }
  
  /// OptionalCalls
  ///   := 'calls' ':' '(' Call [',' Call]* ')'
  /// Call ::= '(' 'callee' ':' GVReference
  ///            [( ',' 'hotness' ':' Hotness | ',' 'relbf' ':' UInt32 )]? ')'
  bool LLParser::parseOptionalCalls(std::vector<FunctionSummary::EdgeTy> &Calls) {
    assert(Lex.getKind() == lltok::kw_calls);
    Lex.Lex();
  
    if (parseToken(lltok::colon, "expected ':' in calls") ||
        parseToken(lltok::lparen, "expected '(' in calls"))
      return true;
  
    IdToIndexMapType IdToIndexMap;
    // parse each call edge
    do {
      ValueInfo VI;
      if (parseToken(lltok::lparen, "expected '(' in call") ||
          parseToken(lltok::kw_callee, "expected 'callee' in call") ||
          parseToken(lltok::colon, "expected ':'"))
        return true;
  
      LocTy Loc = Lex.getLoc();
      unsigned GVId;
      if (parseGVReference(VI, GVId))
        return true;
  
      CalleeInfo::HotnessType Hotness = CalleeInfo::HotnessType::Unknown;
      unsigned RelBF = 0;
      if (EatIfPresent(lltok::comma)) {
        // Expect either hotness or relbf
        if (EatIfPresent(lltok::kw_hotness)) {
          if (parseToken(lltok::colon, "expected ':'") || parseHotness(Hotness))
            return true;
        } else {
          if (parseToken(lltok::kw_relbf, "expected relbf") ||
              parseToken(lltok::colon, "expected ':'") || parseUInt32(RelBF))
            return true;
        }
      }
      // Keep track of the Call array index needing a forward reference.
      // We will save the location of the ValueInfo needing an update, but
      // can only do so once the std::vector is finalized.
      if (VI.getRef() == FwdVIRef)
        IdToIndexMap[GVId].push_back(std::make_pair(Calls.size(), Loc));
      Calls.push_back(FunctionSummary::EdgeTy{VI, CalleeInfo(Hotness, RelBF)});
  
      if (parseToken(lltok::rparen, "expected ')' in call"))
        return true;
    } while (EatIfPresent(lltok::comma));
  
    // Now that the Calls vector is finalized, it is safe to save the locations
    // of any forward GV references that need updating later.
    for (auto I : IdToIndexMap) {
      auto &Infos = ForwardRefValueInfos[I.first];
      for (auto P : I.second) {
        assert(Calls[P.first].first.getRef() == FwdVIRef &&
               "Forward referenced ValueInfo expected to be empty");
        Infos.emplace_back(&Calls[P.first].first, P.second);
      }
    }
  
    if (parseToken(lltok::rparen, "expected ')' in calls"))
      return true;
  
    return false;
  }
  
  /// Hotness
  ///   := ('unknown'|'cold'|'none'|'hot'|'critical')
  bool LLParser::parseHotness(CalleeInfo::HotnessType &Hotness) {
    switch (Lex.getKind()) {
    case lltok::kw_unknown:
      Hotness = CalleeInfo::HotnessType::Unknown;
      break;
    case lltok::kw_cold:
      Hotness = CalleeInfo::HotnessType::Cold;
      break;
    case lltok::kw_none:
      Hotness = CalleeInfo::HotnessType::None;
      break;
    case lltok::kw_hot:
      Hotness = CalleeInfo::HotnessType::Hot;
      break;
    case lltok::kw_critical:
      Hotness = CalleeInfo::HotnessType::Critical;
      break;
    default:
      return error(Lex.getLoc(), "invalid call edge hotness");
    }
    Lex.Lex();
    return false;
  }
  
  /// OptionalVTableFuncs
  ///   := 'vTableFuncs' ':' '(' VTableFunc [',' VTableFunc]* ')'
  /// VTableFunc ::= '(' 'virtFunc' ':' GVReference ',' 'offset' ':' UInt64 ')'
  bool LLParser::parseOptionalVTableFuncs(VTableFuncList &VTableFuncs) {
    assert(Lex.getKind() == lltok::kw_vTableFuncs);
    Lex.Lex();
  
    if (parseToken(lltok::colon, "expected ':' in vTableFuncs") ||
        parseToken(lltok::lparen, "expected '(' in vTableFuncs"))
      return true;
  
    IdToIndexMapType IdToIndexMap;
    // parse each virtual function pair
    do {
      ValueInfo VI;
      if (parseToken(lltok::lparen, "expected '(' in vTableFunc") ||
          parseToken(lltok::kw_virtFunc, "expected 'callee' in vTableFunc") ||
          parseToken(lltok::colon, "expected ':'"))
        return true;
  
      LocTy Loc = Lex.getLoc();
      unsigned GVId;
      if (parseGVReference(VI, GVId))
        return true;
  
      uint64_t Offset;
      if (parseToken(lltok::comma, "expected comma") ||
          parseToken(lltok::kw_offset, "expected offset") ||
          parseToken(lltok::colon, "expected ':'") || parseUInt64(Offset))
        return true;
  
      // Keep track of the VTableFuncs array index needing a forward reference.
      // We will save the location of the ValueInfo needing an update, but
      // can only do so once the std::vector is finalized.
      if (VI == EmptyVI)
        IdToIndexMap[GVId].push_back(std::make_pair(VTableFuncs.size(), Loc));
      VTableFuncs.push_back({VI, Offset});
  
      if (parseToken(lltok::rparen, "expected ')' in vTableFunc"))
        return true;
    } while (EatIfPresent(lltok::comma));
  
    // Now that the VTableFuncs vector is finalized, it is safe to save the
    // locations of any forward GV references that need updating later.
    for (auto I : IdToIndexMap) {
      auto &Infos = ForwardRefValueInfos[I.first];
      for (auto P : I.second) {
        assert(VTableFuncs[P.first].FuncVI == EmptyVI &&
               "Forward referenced ValueInfo expected to be empty");
        Infos.emplace_back(&VTableFuncs[P.first].FuncVI, P.second);
      }
    }
  
    if (parseToken(lltok::rparen, "expected ')' in vTableFuncs"))
      return true;
  
    return false;
  }
  
  /// ParamNo := 'param' ':' UInt64
  bool LLParser::parseParamNo(uint64_t &ParamNo) {
    if (parseToken(lltok::kw_param, "expected 'param' here") ||
        parseToken(lltok::colon, "expected ':' here") || parseUInt64(ParamNo))
      return true;
    return false;
  }
  
  /// ParamAccessOffset := 'offset' ':' '[' APSINTVAL ',' APSINTVAL ']'
  bool LLParser::parseParamAccessOffset(ConstantRange &Range) {
    APSInt Lower;
    APSInt Upper;
    auto ParseAPSInt = [&](APSInt &Val) {
      if (Lex.getKind() != lltok::APSInt)
        return tokError("expected integer");
      Val = Lex.getAPSIntVal();
      Val = Val.extOrTrunc(FunctionSummary::ParamAccess::RangeWidth);
      Val.setIsSigned(true);
      Lex.Lex();
      return false;
    };
    if (parseToken(lltok::kw_offset, "expected 'offset' here") ||
        parseToken(lltok::colon, "expected ':' here") ||
        parseToken(lltok::lsquare, "expected '[' here") || ParseAPSInt(Lower) ||
        parseToken(lltok::comma, "expected ',' here") || ParseAPSInt(Upper) ||
        parseToken(lltok::rsquare, "expected ']' here"))
      return true;
  
    ++Upper;
    Range =
        (Lower == Upper && !Lower.isMaxValue())
            ? ConstantRange::getEmpty(FunctionSummary::ParamAccess::RangeWidth)
            : ConstantRange(Lower, Upper);
  
    return false;
  }
  
  /// ParamAccessCall
  ///   := '(' 'callee' ':' GVReference ',' ParamNo ',' ParamAccessOffset ')'
  bool LLParser::parseParamAccessCall(FunctionSummary::ParamAccess::Call &Call,
                                      IdLocListType &IdLocList) {
    if (parseToken(lltok::lparen, "expected '(' here") ||
        parseToken(lltok::kw_callee, "expected 'callee' here") ||
        parseToken(lltok::colon, "expected ':' here"))
      return true;
  
    unsigned GVId;
    ValueInfo VI;
    LocTy Loc = Lex.getLoc();
    if (parseGVReference(VI, GVId))
      return true;
  
    Call.Callee = VI;
    IdLocList.emplace_back(GVId, Loc);
  
    if (parseToken(lltok::comma, "expected ',' here") ||
        parseParamNo(Call.ParamNo) ||
        parseToken(lltok::comma, "expected ',' here") ||
        parseParamAccessOffset(Call.Offsets))
      return true;
  
    if (parseToken(lltok::rparen, "expected ')' here"))
      return true;
  
    return false;
  }
  
  /// ParamAccess
  ///   := '(' ParamNo ',' ParamAccessOffset [',' OptionalParamAccessCalls]? ')'
  /// OptionalParamAccessCalls := '(' Call [',' Call]* ')'
  bool LLParser::parseParamAccess(FunctionSummary::ParamAccess &Param,
                                  IdLocListType &IdLocList) {
    if (parseToken(lltok::lparen, "expected '(' here") ||
        parseParamNo(Param.ParamNo) ||
        parseToken(lltok::comma, "expected ',' here") ||
        parseParamAccessOffset(Param.Use))
      return true;
  
    if (EatIfPresent(lltok::comma)) {
      if (parseToken(lltok::kw_calls, "expected 'calls' here") ||
          parseToken(lltok::colon, "expected ':' here") ||
          parseToken(lltok::lparen, "expected '(' here"))
        return true;
      do {
        FunctionSummary::ParamAccess::Call Call;
        if (parseParamAccessCall(Call, IdLocList))
          return true;
        Param.Calls.push_back(Call);
      } while (EatIfPresent(lltok::comma));
  
      if (parseToken(lltok::rparen, "expected ')' here"))
        return true;
    }
  
    if (parseToken(lltok::rparen, "expected ')' here"))
      return true;
  
    return false;
  }
  
  /// OptionalParamAccesses
  ///   := 'params' ':' '(' ParamAccess [',' ParamAccess]* ')'
  bool LLParser::parseOptionalParamAccesses(
      std::vector<FunctionSummary::ParamAccess> &Params) {
    assert(Lex.getKind() == lltok::kw_params);
    Lex.Lex();
  
    if (parseToken(lltok::colon, "expected ':' here") ||
        parseToken(lltok::lparen, "expected '(' here"))
      return true;
  
    IdLocListType VContexts;
    size_t CallsNum = 0;
    do {
      FunctionSummary::ParamAccess ParamAccess;
      if (parseParamAccess(ParamAccess, VContexts))
        return true;
      CallsNum += ParamAccess.Calls.size();
      assert(VContexts.size() == CallsNum);
      (void)CallsNum;
      Params.emplace_back(std::move(ParamAccess));
    } while (EatIfPresent(lltok::comma));
  
    if (parseToken(lltok::rparen, "expected ')' here"))
      return true;
  
    // Now that the Params is finalized, it is safe to save the locations
    // of any forward GV references that need updating later.
    IdLocListType::const_iterator ItContext = VContexts.begin();
    for (auto &PA : Params) {
      for (auto &C : PA.Calls) {
        if (C.Callee.getRef() == FwdVIRef)
          ForwardRefValueInfos[ItContext->first].emplace_back(&C.Callee,
                                                              ItContext->second);
        ++ItContext;
      }
    }
    assert(ItContext == VContexts.end());
  
    return false;
  }
  
  /// OptionalRefs
  ///   := 'refs' ':' '(' GVReference [',' GVReference]* ')'
  bool LLParser::parseOptionalRefs(std::vector<ValueInfo> &Refs) {
    assert(Lex.getKind() == lltok::kw_refs);
    Lex.Lex();
  
    if (parseToken(lltok::colon, "expected ':' in refs") ||
        parseToken(lltok::lparen, "expected '(' in refs"))
      return true;
  
    struct ValueContext {
      ValueInfo VI;
      unsigned GVId;
      LocTy Loc;
    };
    std::vector<ValueContext> VContexts;
    // parse each ref edge
    do {
      ValueContext VC;
      VC.Loc = Lex.getLoc();
      if (parseGVReference(VC.VI, VC.GVId))
        return true;
      VContexts.push_back(VC);
    } while (EatIfPresent(lltok::comma));
  
    // Sort value contexts so that ones with writeonly
    // and readonly ValueInfo  are at the end of VContexts vector.
    // See FunctionSummary::specialRefCounts()
    llvm::sort(VContexts, [](const ValueContext &VC1, const ValueContext &VC2) {
      return VC1.VI.getAccessSpecifier() < VC2.VI.getAccessSpecifier();
    });
  
    IdToIndexMapType IdToIndexMap;
    for (auto &VC : VContexts) {
      // Keep track of the Refs array index needing a forward reference.
      // We will save the location of the ValueInfo needing an update, but
      // can only do so once the std::vector is finalized.
      if (VC.VI.getRef() == FwdVIRef)
        IdToIndexMap[VC.GVId].push_back(std::make_pair(Refs.size(), VC.Loc));
      Refs.push_back(VC.VI);
    }
  
    // Now that the Refs vector is finalized, it is safe to save the locations
    // of any forward GV references that need updating later.
    for (auto I : IdToIndexMap) {
      auto &Infos = ForwardRefValueInfos[I.first];
      for (auto P : I.second) {
        assert(Refs[P.first].getRef() == FwdVIRef &&
               "Forward referenced ValueInfo expected to be empty");
        Infos.emplace_back(&Refs[P.first], P.second);
      }
    }
  
    if (parseToken(lltok::rparen, "expected ')' in refs"))
      return true;
  
    return false;
  }
  
  /// OptionalTypeIdInfo
  ///   := 'typeidinfo' ':' '(' [',' TypeTests]? [',' TypeTestAssumeVCalls]?
  ///         [',' TypeCheckedLoadVCalls]?  [',' TypeTestAssumeConstVCalls]?
  ///         [',' TypeCheckedLoadConstVCalls]? ')'
  bool LLParser::parseOptionalTypeIdInfo(
      FunctionSummary::TypeIdInfo &TypeIdInfo) {
    assert(Lex.getKind() == lltok::kw_typeIdInfo);
    Lex.Lex();
  
    if (parseToken(lltok::colon, "expected ':' here") ||
        parseToken(lltok::lparen, "expected '(' in typeIdInfo"))
      return true;
  
    do {
      switch (Lex.getKind()) {
      case lltok::kw_typeTests:
        if (parseTypeTests(TypeIdInfo.TypeTests))
          return true;
        break;
      case lltok::kw_typeTestAssumeVCalls:
        if (parseVFuncIdList(lltok::kw_typeTestAssumeVCalls,
                             TypeIdInfo.TypeTestAssumeVCalls))
          return true;
        break;
      case lltok::kw_typeCheckedLoadVCalls:
        if (parseVFuncIdList(lltok::kw_typeCheckedLoadVCalls,
                             TypeIdInfo.TypeCheckedLoadVCalls))
          return true;
        break;
      case lltok::kw_typeTestAssumeConstVCalls:
        if (parseConstVCallList(lltok::kw_typeTestAssumeConstVCalls,
                                TypeIdInfo.TypeTestAssumeConstVCalls))
          return true;
        break;
      case lltok::kw_typeCheckedLoadConstVCalls:
        if (parseConstVCallList(lltok::kw_typeCheckedLoadConstVCalls,
                                TypeIdInfo.TypeCheckedLoadConstVCalls))
          return true;
        break;
      default:
        return error(Lex.getLoc(), "invalid typeIdInfo list type");
      }
    } while (EatIfPresent(lltok::comma));
  
    if (parseToken(lltok::rparen, "expected ')' in typeIdInfo"))
      return true;
  
    return false;
  }
  
  /// TypeTests
  ///   ::= 'typeTests' ':' '(' (SummaryID | UInt64)
  ///         [',' (SummaryID | UInt64)]* ')'
  bool LLParser::parseTypeTests(std::vector<GlobalValue::GUID> &TypeTests) {
    assert(Lex.getKind() == lltok::kw_typeTests);
    Lex.Lex();
  
    if (parseToken(lltok::colon, "expected ':' here") ||
        parseToken(lltok::lparen, "expected '(' in typeIdInfo"))
      return true;
  
    IdToIndexMapType IdToIndexMap;
    do {
      GlobalValue::GUID GUID = 0;
      if (Lex.getKind() == lltok::SummaryID) {
        unsigned ID = Lex.getUIntVal();
        LocTy Loc = Lex.getLoc();
        // Keep track of the TypeTests array index needing a forward reference.
        // We will save the location of the GUID needing an update, but
        // can only do so once the std::vector is finalized.
        IdToIndexMap[ID].push_back(std::make_pair(TypeTests.size(), Loc));
        Lex.Lex();
      } else if (parseUInt64(GUID))
        return true;
      TypeTests.push_back(GUID);
    } while (EatIfPresent(lltok::comma));
  
    // Now that the TypeTests vector is finalized, it is safe to save the
    // locations of any forward GV references that need updating later.
    for (auto I : IdToIndexMap) {
      auto &Ids = ForwardRefTypeIds[I.first];
      for (auto P : I.second) {
        assert(TypeTests[P.first] == 0 &&
               "Forward referenced type id GUID expected to be 0");
        Ids.emplace_back(&TypeTests[P.first], P.second);
      }
    }
  
    if (parseToken(lltok::rparen, "expected ')' in typeIdInfo"))
      return true;
  
    return false;
  }
  
  /// VFuncIdList
  ///   ::= Kind ':' '(' VFuncId [',' VFuncId]* ')'
  bool LLParser::parseVFuncIdList(
      lltok::Kind Kind, std::vector<FunctionSummary::VFuncId> &VFuncIdList) {
    assert(Lex.getKind() == Kind);
    Lex.Lex();
  
    if (parseToken(lltok::colon, "expected ':' here") ||
        parseToken(lltok::lparen, "expected '(' here"))
      return true;
  
    IdToIndexMapType IdToIndexMap;
    do {
      FunctionSummary::VFuncId VFuncId;
      if (parseVFuncId(VFuncId, IdToIndexMap, VFuncIdList.size()))
        return true;
      VFuncIdList.push_back(VFuncId);
    } while (EatIfPresent(lltok::comma));
  
    if (parseToken(lltok::rparen, "expected ')' here"))
      return true;
  
    // Now that the VFuncIdList vector is finalized, it is safe to save the
    // locations of any forward GV references that need updating later.
    for (auto I : IdToIndexMap) {
      auto &Ids = ForwardRefTypeIds[I.first];
      for (auto P : I.second) {
        assert(VFuncIdList[P.first].GUID == 0 &&
               "Forward referenced type id GUID expected to be 0");
        Ids.emplace_back(&VFuncIdList[P.first].GUID, P.second);
      }
    }
  
    return false;
  }
  
  /// ConstVCallList
  ///   ::= Kind ':' '(' ConstVCall [',' ConstVCall]* ')'
  bool LLParser::parseConstVCallList(
      lltok::Kind Kind,
      std::vector<FunctionSummary::ConstVCall> &ConstVCallList) {
    assert(Lex.getKind() == Kind);
    Lex.Lex();
  
    if (parseToken(lltok::colon, "expected ':' here") ||
        parseToken(lltok::lparen, "expected '(' here"))
      return true;
  
    IdToIndexMapType IdToIndexMap;
    do {
      FunctionSummary::ConstVCall ConstVCall;
      if (parseConstVCall(ConstVCall, IdToIndexMap, ConstVCallList.size()))
        return true;
      ConstVCallList.push_back(ConstVCall);
    } while (EatIfPresent(lltok::comma));
  
    if (parseToken(lltok::rparen, "expected ')' here"))
      return true;
  
    // Now that the ConstVCallList vector is finalized, it is safe to save the
    // locations of any forward GV references that need updating later.
    for (auto I : IdToIndexMap) {
      auto &Ids = ForwardRefTypeIds[I.first];
      for (auto P : I.second) {
        assert(ConstVCallList[P.first].VFunc.GUID == 0 &&
               "Forward referenced type id GUID expected to be 0");
        Ids.emplace_back(&ConstVCallList[P.first].VFunc.GUID, P.second);
      }
    }
  
    return false;
  }
  
  /// ConstVCall
  ///   ::= '(' VFuncId ',' Args ')'
  bool LLParser::parseConstVCall(FunctionSummary::ConstVCall &ConstVCall,
                                 IdToIndexMapType &IdToIndexMap, unsigned Index) {
    if (parseToken(lltok::lparen, "expected '(' here") ||
        parseVFuncId(ConstVCall.VFunc, IdToIndexMap, Index))
      return true;
  
    if (EatIfPresent(lltok::comma))
      if (parseArgs(ConstVCall.Args))
        return true;
  
    if (parseToken(lltok::rparen, "expected ')' here"))
      return true;
  
    return false;
  }
  
  /// VFuncId
  ///   ::= 'vFuncId' ':' '(' (SummaryID | 'guid' ':' UInt64) ','
  ///         'offset' ':' UInt64 ')'
  bool LLParser::parseVFuncId(FunctionSummary::VFuncId &VFuncId,
                              IdToIndexMapType &IdToIndexMap, unsigned Index) {
    assert(Lex.getKind() == lltok::kw_vFuncId);
    Lex.Lex();
  
    if (parseToken(lltok::colon, "expected ':' here") ||
        parseToken(lltok::lparen, "expected '(' here"))
      return true;
  
    if (Lex.getKind() == lltok::SummaryID) {
      VFuncId.GUID = 0;
      unsigned ID = Lex.getUIntVal();
      LocTy Loc = Lex.getLoc();
      // Keep track of the array index needing a forward reference.
      // We will save the location of the GUID needing an update, but
      // can only do so once the caller's std::vector is finalized.
      IdToIndexMap[ID].push_back(std::make_pair(Index, Loc));
      Lex.Lex();
    } else if (parseToken(lltok::kw_guid, "expected 'guid' here") ||
               parseToken(lltok::colon, "expected ':' here") ||
               parseUInt64(VFuncId.GUID))
      return true;
  
    if (parseToken(lltok::comma, "expected ',' here") ||
        parseToken(lltok::kw_offset, "expected 'offset' here") ||
        parseToken(lltok::colon, "expected ':' here") ||
        parseUInt64(VFuncId.Offset) ||
        parseToken(lltok::rparen, "expected ')' here"))
      return true;
  
    return false;
  }
  
  /// GVFlags
  ///   ::= 'flags' ':' '(' 'linkage' ':' OptionalLinkageAux ','
  ///         'visibility' ':' Flag 'notEligibleToImport' ':' Flag ','
  ///         'live' ':' Flag ',' 'dsoLocal' ':' Flag ','
  ///         'canAutoHide' ':' Flag ',' ')'
  bool LLParser::parseGVFlags(GlobalValueSummary::GVFlags &GVFlags) {
    assert(Lex.getKind() == lltok::kw_flags);
    Lex.Lex();
  
    if (parseToken(lltok::colon, "expected ':' here") ||
        parseToken(lltok::lparen, "expected '(' here"))
      return true;
  
    do {
      unsigned Flag = 0;
      switch (Lex.getKind()) {
      case lltok::kw_linkage:
        Lex.Lex();
        if (parseToken(lltok::colon, "expected ':'"))
          return true;
        bool HasLinkage;
        GVFlags.Linkage = parseOptionalLinkageAux(Lex.getKind(), HasLinkage);
        assert(HasLinkage && "Linkage not optional in summary entry");
        Lex.Lex();
        break;
      case lltok::kw_visibility:
        Lex.Lex();
        if (parseToken(lltok::colon, "expected ':'"))
          return true;
        parseOptionalVisibility(Flag);
        GVFlags.Visibility = Flag;
        break;
      case lltok::kw_notEligibleToImport:
        Lex.Lex();
        if (parseToken(lltok::colon, "expected ':'") || parseFlag(Flag))
          return true;
        GVFlags.NotEligibleToImport = Flag;
        break;
      case lltok::kw_live:
        Lex.Lex();
        if (parseToken(lltok::colon, "expected ':'") || parseFlag(Flag))
          return true;
        GVFlags.Live = Flag;
        break;
      case lltok::kw_dsoLocal:
        Lex.Lex();
        if (parseToken(lltok::colon, "expected ':'") || parseFlag(Flag))
          return true;
        GVFlags.DSOLocal = Flag;
        break;
      case lltok::kw_canAutoHide:
        Lex.Lex();
        if (parseToken(lltok::colon, "expected ':'") || parseFlag(Flag))
          return true;
        GVFlags.CanAutoHide = Flag;
        break;
      default:
        return error(Lex.getLoc(), "expected gv flag type");
      }
    } while (EatIfPresent(lltok::comma));
  
    if (parseToken(lltok::rparen, "expected ')' here"))
      return true;
  
    return false;
  }
  
  /// GVarFlags
  ///   ::= 'varFlags' ':' '(' 'readonly' ':' Flag
  ///                      ',' 'writeonly' ':' Flag
  ///                      ',' 'constant' ':' Flag ')'
  bool LLParser::parseGVarFlags(GlobalVarSummary::GVarFlags &GVarFlags) {
    assert(Lex.getKind() == lltok::kw_varFlags);
    Lex.Lex();
  
    if (parseToken(lltok::colon, "expected ':' here") ||
        parseToken(lltok::lparen, "expected '(' here"))
      return true;
  
    auto ParseRest = [this](unsigned int &Val) {
      Lex.Lex();
      if (parseToken(lltok::colon, "expected ':'"))
        return true;
      return parseFlag(Val);
    };
  
    do {
      unsigned Flag = 0;
      switch (Lex.getKind()) {
      case lltok::kw_readonly:
        if (ParseRest(Flag))
          return true;
        GVarFlags.MaybeReadOnly = Flag;
        break;
      case lltok::kw_writeonly:
        if (ParseRest(Flag))
          return true;
        GVarFlags.MaybeWriteOnly = Flag;
        break;
      case lltok::kw_constant:
        if (ParseRest(Flag))
          return true;
        GVarFlags.Constant = Flag;
        break;
      case lltok::kw_vcall_visibility:
        if (ParseRest(Flag))
          return true;
        GVarFlags.VCallVisibility = Flag;
        break;
      default:
        return error(Lex.getLoc(), "expected gvar flag type");
      }
    } while (EatIfPresent(lltok::comma));
    return parseToken(lltok::rparen, "expected ')' here");
  }
  
  /// ModuleReference
  ///   ::= 'module' ':' UInt
  bool LLParser::parseModuleReference(StringRef &ModulePath) {
    // parse module id.
    if (parseToken(lltok::kw_module, "expected 'module' here") ||
        parseToken(lltok::colon, "expected ':' here") ||
        parseToken(lltok::SummaryID, "expected module ID"))
      return true;
  
    unsigned ModuleID = Lex.getUIntVal();
    auto I = ModuleIdMap.find(ModuleID);
    // We should have already parsed all module IDs
    assert(I != ModuleIdMap.end());
    ModulePath = I->second;
    return false;
  }
  
  /// GVReference
  ///   ::= SummaryID
  bool LLParser::parseGVReference(ValueInfo &VI, unsigned &GVId) {
    bool WriteOnly = false, ReadOnly = EatIfPresent(lltok::kw_readonly);
    if (!ReadOnly)
      WriteOnly = EatIfPresent(lltok::kw_writeonly);
    if (parseToken(lltok::SummaryID, "expected GV ID"))
      return true;
  
    GVId = Lex.getUIntVal();
    // Check if we already have a VI for this GV
    if (GVId < NumberedValueInfos.size()) {
      assert(NumberedValueInfos[GVId].getRef() != FwdVIRef);
      VI = NumberedValueInfos[GVId];
    } else
      // We will create a forward reference to the stored location.
      VI = ValueInfo(false, FwdVIRef);
  
    if (ReadOnly)
      VI.setReadOnly();
    if (WriteOnly)
      VI.setWriteOnly();
    return false;
  }
  