text: //===- llvm/lib/CodeGen/AsmPrinter/CodeViewDebug.h --------------*- C++ -*-===//
  //
  // 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 contains support for writing Microsoft CodeView debug info.
  //
  //===----------------------------------------------------------------------===//
  
  #ifndef LLVM_LIB_CODEGEN_ASMPRINTER_CODEVIEWDEBUG_H
  #define LLVM_LIB_CODEGEN_ASMPRINTER_CODEVIEWDEBUG_H
  
  #include "llvm/ADT/ArrayRef.h"
  #include "llvm/ADT/DenseMap.h"
  #include "llvm/ADT/DenseSet.h"
  #include "llvm/ADT/MapVector.h"
  #include "llvm/ADT/PointerUnion.h"
  #include "llvm/ADT/SetVector.h"
  #include "llvm/ADT/SmallVector.h"
  #include "llvm/CodeGen/DbgEntityHistoryCalculator.h"
  #include "llvm/CodeGen/DebugHandlerBase.h"
  #include "llvm/DebugInfo/CodeView/CodeView.h"
  #include "llvm/DebugInfo/CodeView/GlobalTypeTableBuilder.h"
  #include "llvm/DebugInfo/CodeView/TypeIndex.h"
  #include "llvm/IR/DebugLoc.h"
  #include "llvm/Support/Allocator.h"
  #include "llvm/Support/Compiler.h"
  #include <cstdint>
  #include <map>
  #include <string>
  #include <tuple>
  #include <unordered_map>
  #include <utility>
  #include <vector>
  
  namespace llvm {
  
  struct ClassInfo;
  class StringRef;
  class AsmPrinter;
  class Function;
  class GlobalVariable;
  class MCSectionCOFF;
  class MCStreamer;
  class MCSymbol;
  class MachineFunction;
  
  /// Collects and handles line tables information in a CodeView format.
  class LLVM_LIBRARY_VISIBILITY CodeViewDebug : public DebugHandlerBase {
    MCStreamer &OS;
    BumpPtrAllocator Allocator;
    codeview::GlobalTypeTableBuilder TypeTable;
  
    /// Whether to emit type record hashes into .debug$H.
    bool EmitDebugGlobalHashes = false;
  
    /// The codeview CPU type used by the translation unit.
    codeview::CPUType TheCPU;
  
    /// Represents the most general definition range.
    struct LocalVarDefRange {
      /// Indicates that variable data is stored in memory relative to the
      /// specified register.
      int InMemory : 1;
  
      /// Offset of variable data in memory.
      int DataOffset : 31;
  
      /// Non-zero if this is a piece of an aggregate.
      uint16_t IsSubfield : 1;
  
      /// Offset into aggregate.
      uint16_t StructOffset : 15;
  
      /// Register containing the data or the register base of the memory
      /// location containing the data.
      uint16_t CVRegister;
  
      /// Compares all location fields. This includes all fields except the label
      /// ranges.
      bool isDifferentLocation(LocalVarDefRange &O) {
        return InMemory != O.InMemory || DataOffset != O.DataOffset ||
               IsSubfield != O.IsSubfield || StructOffset != O.StructOffset ||
               CVRegister != O.CVRegister;
      }
  
      SmallVector<std::pair<const MCSymbol *, const MCSymbol *>, 1> Ranges;
    };
  
    static LocalVarDefRange createDefRangeMem(uint16_t CVRegister, int Offset);
  
    /// Similar to DbgVariable in DwarfDebug, but not dwarf-specific.
    struct LocalVariable {
      const DILocalVariable *DIVar = nullptr;
      SmallVector<LocalVarDefRange, 1> DefRanges;
      bool UseReferenceType = false;
    };
  
    struct CVGlobalVariable {
      const DIGlobalVariable *DIGV;
      PointerUnion<const GlobalVariable *, const DIExpression *> GVInfo;
    };
  
    struct InlineSite {
      SmallVector<LocalVariable, 1> InlinedLocals;
      SmallVector<const DILocation *, 1> ChildSites;
      const DISubprogram *Inlinee = nullptr;
  
      /// The ID of the inline site or function used with .cv_loc. Not a type
      /// index.
      unsigned SiteFuncId = 0;
    };
  
    // Combines information from DILexicalBlock and LexicalScope.
    struct LexicalBlock {
      SmallVector<LocalVariable, 1> Locals;
      SmallVector<CVGlobalVariable, 1> Globals;
      SmallVector<LexicalBlock *, 1> Children;
      const MCSymbol *Begin;
      const MCSymbol *End;
      StringRef Name;
    };
  
    // For each function, store a vector of labels to its instructions, as well as
    // to the end of the function.
    struct FunctionInfo {
      FunctionInfo() = default;
  
      // Uncopyable.
      FunctionInfo(const FunctionInfo &FI) = delete;
  
      /// Map from inlined call site to inlined instructions and child inlined
      /// call sites. Listed in program order.
      std::unordered_map<const DILocation *, InlineSite> InlineSites;
  
      /// Ordered list of top-level inlined call sites.
      SmallVector<const DILocation *, 1> ChildSites;
  
      SmallVector<LocalVariable, 1> Locals;
      SmallVector<CVGlobalVariable, 1> Globals;
  
      std::unordered_map<const DILexicalBlockBase*, LexicalBlock> LexicalBlocks;
  
      // Lexical blocks containing local variables.
      SmallVector<LexicalBlock *, 1> ChildBlocks;
  
      std::vector<std::pair<MCSymbol *, MDNode *>> Annotations;
      std::vector<std::tuple<const MCSymbol *, const MCSymbol *, const DIType *>>
          HeapAllocSites;
  
      const MCSymbol *Begin = nullptr;
      const MCSymbol *End = nullptr;
      unsigned FuncId = 0;
      unsigned LastFileId = 0;
  
      /// Number of bytes allocated in the prologue for all local stack objects.
      unsigned FrameSize = 0;
  
      /// Number of bytes of parameters on the stack.
      unsigned ParamSize = 0;
  
      /// Number of bytes pushed to save CSRs.
      unsigned CSRSize = 0;
  
      /// Adjustment to apply on x86 when using the VFRAME frame pointer.
      int OffsetAdjustment = 0;
  
      /// Two-bit value indicating which register is the designated frame pointer
      /// register for local variables. Included in S_FRAMEPROC.
      codeview::EncodedFramePtrReg EncodedLocalFramePtrReg =
          codeview::EncodedFramePtrReg::None;
  
      /// Two-bit value indicating which register is the designated frame pointer
      /// register for stack parameters. Included in S_FRAMEPROC.
      codeview::EncodedFramePtrReg EncodedParamFramePtrReg =
          codeview::EncodedFramePtrReg::None;
  
      codeview::FrameProcedureOptions FrameProcOpts;
  
      bool HasStackRealignment = false;
  
      bool HaveLineInfo = false;
    };
    FunctionInfo *CurFn = nullptr;
  
    codeview::SourceLanguage CurrentSourceLanguage =
        codeview::SourceLanguage::Masm;
  
    // This map records the constant offset in DIExpression of the
    // DIGlobalVariableExpression referencing the DIGlobalVariable.
    DenseMap<const DIGlobalVariable *, uint64_t> CVGlobalVariableOffsets;
  
    // Map used to seperate variables according to the lexical scope they belong
    // in.  This is populated by recordLocalVariable() before
    // collectLexicalBlocks() separates the variables between the FunctionInfo
    // and LexicalBlocks.
    DenseMap<const LexicalScope *, SmallVector<LocalVariable, 1>> ScopeVariables;
  
    // Map to separate global variables according to the lexical scope they
    // belong in. A null local scope represents the global scope.
    typedef SmallVector<CVGlobalVariable, 1> GlobalVariableList;
    DenseMap<const DIScope*, std::unique_ptr<GlobalVariableList> > ScopeGlobals;
  
    // Array of global variables which  need to be emitted into a COMDAT section.
    SmallVector<CVGlobalVariable, 1> ComdatVariables;
  
    // Array of non-COMDAT global variables.
    SmallVector<CVGlobalVariable, 1> GlobalVariables;
  
    /// List of static const data members to be emitted as S_CONSTANTs.
    SmallVector<const DIDerivedType *, 4> StaticConstMembers;
  
    /// The set of comdat .debug$S sections that we've seen so far. Each section
    /// must start with a magic version number that must only be emitted once.
    /// This set tracks which sections we've already opened.
    DenseSet<MCSectionCOFF *> ComdatDebugSections;
  
    /// Switch to the appropriate .debug$S section for GVSym. If GVSym, the symbol
    /// of an emitted global value, is in a comdat COFF section, this will switch
    /// to a new .debug$S section in that comdat. This method ensures that the
    /// section starts with the magic version number on first use. If GVSym is
    /// null, uses the main .debug$S section.
    void switchToDebugSectionForSymbol(const MCSymbol *GVSym);
  
    /// The next available function index for use with our .cv_* directives. Not
    /// to be confused with type indices for LF_FUNC_ID records.
    unsigned NextFuncId = 0;
  
    InlineSite &getInlineSite(const DILocation *InlinedAt,
                              const DISubprogram *Inlinee);
  
    codeview::TypeIndex getFuncIdForSubprogram(const DISubprogram *SP);
  
    void calculateRanges(LocalVariable &Var,
                         const DbgValueHistoryMap::Entries &Entries);
  
    /// Remember some debug info about each function. Keep it in a stable order to
    /// emit at the end of the TU.
    MapVector<const Function *, std::unique_ptr<FunctionInfo>> FnDebugInfo;
  
    /// Map from full file path to .cv_file id. Full paths are built from DIFiles
    /// and are stored in FileToFilepathMap;
    DenseMap<StringRef, unsigned> FileIdMap;
  
    /// All inlined subprograms in the order they should be emitted.
    SmallSetVector<const DISubprogram *, 4> InlinedSubprograms;
  
    /// Map from a pair of DI metadata nodes and its DI type (or scope) that can
    /// be nullptr, to CodeView type indices. Primarily indexed by
    /// {DIType*, DIType*} and {DISubprogram*, DIType*}.
    ///
    /// The second entry in the key is needed for methods as DISubroutineType
    /// representing static method type are shared with non-method function type.
    DenseMap<std::pair<const DINode *, const DIType *>, codeview::TypeIndex>
        TypeIndices;
  
    /// Map from DICompositeType* to complete type index. Non-record types are
    /// always looked up in the normal TypeIndices map.
    DenseMap<const DICompositeType *, codeview::TypeIndex> CompleteTypeIndices;
  
    /// Complete record types to emit after all active type lowerings are
    /// finished.
    SmallVector<const DICompositeType *, 4> DeferredCompleteTypes;
  
    /// Number of type lowering frames active on the stack.
    unsigned TypeEmissionLevel = 0;
  
    codeview::TypeIndex VBPType;
  
    const DISubprogram *CurrentSubprogram = nullptr;
  
    // The UDTs we have seen while processing types; each entry is a pair of type
    // index and type name.
    std::vector<std::pair<std::string, const DIType *>> LocalUDTs;
    std::vector<std::pair<std::string, const DIType *>> GlobalUDTs;
  
    using FileToFilepathMapTy = std::map<const DIFile *, std::string>;
    FileToFilepathMapTy FileToFilepathMap;
  
    StringRef getFullFilepath(const DIFile *File);
  
    unsigned maybeRecordFile(const DIFile *F);
  
    void maybeRecordLocation(const DebugLoc &DL, const MachineFunction *MF);
  
    void clear();
  
    void setCurrentSubprogram(const DISubprogram *SP) {
      CurrentSubprogram = SP;
      LocalUDTs.clear();
    }
  
    /// Emit the magic version number at the start of a CodeView type or symbol
    /// section. Appears at the front of every .debug$S or .debug$T or .debug$P
    /// section.
    void emitCodeViewMagicVersion();
  
    void emitTypeInformation();
  
    void emitTypeGlobalHashes();
  
    void emitObjName();
  
    void emitCompilerInformation();
  
    void emitBuildInfo();
  
    void emitInlineeLinesSubsection();
  
    void emitDebugInfoForThunk(const Function *GV,
                               FunctionInfo &FI,
                               const MCSymbol *Fn);
  
    void emitDebugInfoForFunction(const Function *GV, FunctionInfo &FI);
  
    void emitDebugInfoForRetainedTypes();
  
    void emitDebugInfoForUDTs(
        const std::vector<std::pair<std::string, const DIType *>> &UDTs);
  
    void collectDebugInfoForGlobals();
    void emitDebugInfoForGlobals();
    void emitGlobalVariableList(ArrayRef<CVGlobalVariable> Globals);
    void emitConstantSymbolRecord(const DIType *DTy, APSInt &Value,
                                  const std::string &QualifiedName);
    void emitDebugInfoForGlobal(const CVGlobalVariable &CVGV);
    void emitStaticConstMemberList();
  
    /// Opens a subsection of the given kind in a .debug$S codeview section.
    /// Returns an end label for use with endCVSubsection when the subsection is
    /// finished.
    MCSymbol *beginCVSubsection(codeview::DebugSubsectionKind Kind);
    void endCVSubsection(MCSymbol *EndLabel);
  
    /// Opens a symbol record of the given kind. Returns an end label for use with
    /// endSymbolRecord.
    MCSymbol *beginSymbolRecord(codeview::SymbolKind Kind);
    void endSymbolRecord(MCSymbol *SymEnd);
  
    /// Emits an S_END, S_INLINESITE_END, or S_PROC_ID_END record. These records
    /// are empty, so we emit them with a simpler assembly sequence that doesn't
    /// involve labels.
    void emitEndSymbolRecord(codeview::SymbolKind EndKind);
  
    void emitInlinedCallSite(const FunctionInfo &FI, const DILocation *InlinedAt,
                             const InlineSite &Site);
  
    using InlinedEntity = DbgValueHistoryMap::InlinedEntity;
  
    void collectGlobalVariableInfo();
    void collectVariableInfo(const DISubprogram *SP);
  
    void collectVariableInfoFromMFTable(DenseSet<InlinedEntity> &Processed);
  
    // Construct the lexical block tree for a routine, pruning emptpy lexical
    // scopes, and populate it with local variables.
    void collectLexicalBlockInfo(SmallVectorImpl<LexicalScope *> &Scopes,
                                 SmallVectorImpl<LexicalBlock *> &Blocks,
                                 SmallVectorImpl<LocalVariable> &Locals,
                                 SmallVectorImpl<CVGlobalVariable> &Globals);
    void collectLexicalBlockInfo(LexicalScope &Scope,
                                 SmallVectorImpl<LexicalBlock *> &ParentBlocks,
                                 SmallVectorImpl<LocalVariable> &ParentLocals,
                                 SmallVectorImpl<CVGlobalVariable> &ParentGlobals);
  
    /// Records information about a local variable in the appropriate scope. In
    /// particular, locals from inlined code live inside the inlining site.
    void recordLocalVariable(LocalVariable &&Var, const LexicalScope *LS);
  
    /// Emits local variables in the appropriate order.
    void emitLocalVariableList(const FunctionInfo &FI,
                               ArrayRef<LocalVariable> Locals);
  
    /// Emits an S_LOCAL record and its associated defined ranges.
    void emitLocalVariable(const FunctionInfo &FI, const LocalVariable &Var);
  
    /// Emits a sequence of lexical block scopes and their children.
    void emitLexicalBlockList(ArrayRef<LexicalBlock *> Blocks,
                              const FunctionInfo& FI);
  
    /// Emit a lexical block scope and its children.
    void emitLexicalBlock(const LexicalBlock &Block, const FunctionInfo& FI);
  
    /// Translates the DIType to codeview if necessary and returns a type index
    /// for it.
    codeview::TypeIndex getTypeIndex(const DIType *Ty,
                                     const DIType *ClassTy = nullptr);
  
    codeview::TypeIndex
    getTypeIndexForThisPtr(const DIDerivedType *PtrTy,
                           const DISubroutineType *SubroutineTy);
  
    codeview::TypeIndex getTypeIndexForReferenceTo(const DIType *Ty);
  
    codeview::TypeIndex getMemberFunctionType(const DISubprogram *SP,
                                              const DICompositeType *Class);
  
    codeview::TypeIndex getScopeIndex(const DIScope *Scope);
  
    codeview::TypeIndex getVBPTypeIndex();
  
    void addToUDTs(const DIType *Ty);
  
    void addUDTSrcLine(const DIType *Ty, codeview::TypeIndex TI);
  
    codeview::TypeIndex lowerType(const DIType *Ty, const DIType *ClassTy);
    codeview::TypeIndex lowerTypeAlias(const DIDerivedType *Ty);
    codeview::TypeIndex lowerTypeArray(const DICompositeType *Ty);
    codeview::TypeIndex lowerTypeString(const DIStringType *Ty);
    codeview::TypeIndex lowerTypeBasic(const DIBasicType *Ty);
    codeview::TypeIndex lowerTypePointer(
        const DIDerivedType *Ty,
        codeview::PointerOptions PO = codeview::PointerOptions::None);
    codeview::TypeIndex lowerTypeMemberPointer(
        const DIDerivedType *Ty,
        codeview::PointerOptions PO = codeview::PointerOptions::None);
    codeview::TypeIndex lowerTypeModifier(const DIDerivedType *Ty);
    codeview::TypeIndex lowerTypeFunction(const DISubroutineType *Ty);
    codeview::TypeIndex lowerTypeVFTableShape(const DIDerivedType *Ty);
    codeview::TypeIndex lowerTypeMemberFunction(
        const DISubroutineType *Ty, const DIType *ClassTy, int ThisAdjustment,
        bool IsStaticMethod,
        codeview::FunctionOptions FO = codeview::FunctionOptions::None);
    codeview::TypeIndex lowerTypeEnum(const DICompositeType *Ty);
    codeview::TypeIndex lowerTypeClass(const DICompositeType *Ty);
    codeview::TypeIndex lowerTypeUnion(const DICompositeType *Ty);
  
    /// Symbol records should point to complete types, but type records should
    /// always point to incomplete types to avoid cycles in the type graph. Only
    /// use this entry point when generating symbol records. The complete and
    /// incomplete type indices only differ for record types. All other types use
    /// the same index.
    codeview::TypeIndex getCompleteTypeIndex(const DIType *Ty);
  
    codeview::TypeIndex lowerCompleteTypeClass(const DICompositeType *Ty);
    codeview::TypeIndex lowerCompleteTypeUnion(const DICompositeType *Ty);
  
    struct TypeLoweringScope;
  
    void emitDeferredCompleteTypes();
  
    void collectMemberInfo(ClassInfo &Info, const DIDerivedType *DDTy);
    ClassInfo collectClassInfo(const DICompositeType *Ty);
  
    /// Common record member lowering functionality for record types, which are
    /// structs, classes, and unions. Returns the field list index and the member
    /// count.
    std::tuple<codeview::TypeIndex, codeview::TypeIndex, unsigned, bool>
    lowerRecordFieldList(const DICompositeType *Ty);
  
    /// Inserts {{Node, ClassTy}, TI} into TypeIndices and checks for duplicates.
    codeview::TypeIndex recordTypeIndexForDINode(const DINode *Node,
                                                 codeview::TypeIndex TI,
                                                 const DIType *ClassTy = nullptr);
  
    /// Collect the names of parent scopes, innermost to outermost. Return the
    /// innermost subprogram scope if present. Ensure that parent type scopes are
    /// inserted into the type table.
    const DISubprogram *
    collectParentScopeNames(const DIScope *Scope,
                            SmallVectorImpl<StringRef> &ParentScopeNames);
    std::string getFullyQualifiedName(const DIScope *Scope, StringRef Name);
    std::string getFullyQualifiedName(const DIScope *Scope);
  
    unsigned getPointerSizeInBytes();
  
  protected:
    /// Gather pre-function debug information.
    void beginFunctionImpl(const MachineFunction *MF) override;
  
    /// Gather post-function debug information.
    void endFunctionImpl(const MachineFunction *) override;
  
    /// Check if the current module is in Fortran.
    bool moduleIsInFortran() {
      return CurrentSourceLanguage == codeview::SourceLanguage::Fortran;
    }
  
  public:
    CodeViewDebug(AsmPrinter *AP);
  
    void beginModule(Module *M) override;
  
    void setSymbolSize(const MCSymbol *, uint64_t) override {}
  
    /// Emit the COFF section that holds the line table information.
    void endModule() override;
  
    /// Process beginning of an instruction.
    void beginInstruction(const MachineInstr *MI) override;
  };
  
  } // end namespace llvm
  
  #endif // LLVM_LIB_CODEGEN_ASMPRINTER_CODEVIEWDEBUG_H
  