text: //===-- XCoreAsmPrinter.cpp - XCore LLVM assembly writer ------------------===//
  //
  //                     The LLVM Compiler Infrastructure
  //
  // This file is distributed under the University of Illinois Open Source
  // License. See LICENSE.TXT for details.
  //
  //===----------------------------------------------------------------------===//
  //
  // This file contains a printer that converts from our internal representation
  // of machine-dependent LLVM code to the XAS-format XCore assembly language.
  //
  //===----------------------------------------------------------------------===//
  
  #include "XCore.h"
  #include "InstPrinter/XCoreInstPrinter.h"
  #include "XCoreInstrInfo.h"
  #include "XCoreMCInstLower.h"
  #include "XCoreSubtarget.h"
  #include "XCoreTargetMachine.h"
  #include "XCoreTargetStreamer.h"
  #include "llvm/ADT/SmallString.h"
  #include "llvm/ADT/StringExtras.h"
  #include "llvm/CodeGen/AsmPrinter.h"
  #include "llvm/CodeGen/MachineConstantPool.h"
  #include "llvm/CodeGen/MachineFunctionPass.h"
  #include "llvm/CodeGen/MachineInstr.h"
  #include "llvm/CodeGen/MachineJumpTableInfo.h"
  #include "llvm/CodeGen/MachineModuleInfo.h"
  #include "llvm/IR/Constants.h"
  #include "llvm/IR/DataLayout.h"
  #include "llvm/IR/DebugInfo.h"
  #include "llvm/IR/DerivedTypes.h"
  #include "llvm/IR/Mangler.h"
  #include "llvm/IR/Module.h"
  #include "llvm/MC/MCAsmInfo.h"
  #include "llvm/MC/MCExpr.h"
  #include "llvm/MC/MCInst.h"
  #include "llvm/MC/MCStreamer.h"
  #include "llvm/MC/MCSymbol.h"
  #include "llvm/Support/ErrorHandling.h"
  #include "llvm/Support/TargetRegistry.h"
  #include "llvm/Support/raw_ostream.h"
  #include "llvm/Target/TargetLoweringObjectFile.h"
  #include <algorithm>
  #include <cctype>
  using namespace llvm;
  
  #define DEBUG_TYPE "asm-printer"
  
  namespace {
    class XCoreAsmPrinter : public AsmPrinter {
      const XCoreSubtarget &Subtarget;
      XCoreMCInstLower MCInstLowering;
      XCoreTargetStreamer &getTargetStreamer();
  
    public:
      explicit XCoreAsmPrinter(TargetMachine &TM, MCStreamer &Streamer)
        : AsmPrinter(TM, Streamer), Subtarget(TM.getSubtarget<XCoreSubtarget>()),
          MCInstLowering(*this) {}
  
      const char *getPassName() const override {
        return "XCore Assembly Printer";
      }
  
      void printInlineJT(const MachineInstr *MI, int opNum, raw_ostream &O,
                         const std::string &directive = ".jmptable");
      void printInlineJT32(const MachineInstr *MI, int opNum, raw_ostream &O) {
        printInlineJT(MI, opNum, O, ".jmptable32");
      }
      void printOperand(const MachineInstr *MI, int opNum, raw_ostream &O);
      bool PrintAsmOperand(const MachineInstr *MI, unsigned OpNo,
                           unsigned AsmVariant, const char *ExtraCode,
                           raw_ostream &O) override;
      bool PrintAsmMemoryOperand(const MachineInstr *MI, unsigned OpNum,
                                 unsigned AsmVariant, const char *ExtraCode,
                                 raw_ostream &O) override;
  
      void emitArrayBound(MCSymbol *Sym, const GlobalVariable *GV);
      void EmitGlobalVariable(const GlobalVariable *GV) override;
  
      void EmitFunctionEntryLabel() override;
      void EmitInstruction(const MachineInstr *MI) override;
      void EmitFunctionBodyStart() override;
      void EmitFunctionBodyEnd() override;
    };
  } // end of anonymous namespace
  
  XCoreTargetStreamer &XCoreAsmPrinter::getTargetStreamer() {
    return static_cast<XCoreTargetStreamer&>(*OutStreamer.getTargetStreamer());
  }
  
  void XCoreAsmPrinter::emitArrayBound(MCSymbol *Sym, const GlobalVariable *GV) {
    assert( ( GV->hasExternalLinkage() || GV->hasWeakLinkage() ||
              GV->hasLinkOnceLinkage() || GV->hasCommonLinkage() ) &&
            "Unexpected linkage");
    if (ArrayType *ATy = dyn_cast<ArrayType>(
                          cast<PointerType>(GV->getType())->getElementType())) {
  
      MCSymbol *SymGlob = OutContext.GetOrCreateSymbol(
                            Twine(Sym->getName() + StringRef(".globound")));
      OutStreamer.EmitSymbolAttribute(SymGlob, MCSA_Global);
      OutStreamer.EmitAssignment(SymGlob,
                                 MCConstantExpr::Create(ATy->getNumElements(),
                                                        OutContext));
      if (GV->hasWeakLinkage() || GV->hasLinkOnceLinkage() ||
          GV->hasCommonLinkage()) {
        // TODO Use COMDAT groups for LinkOnceLinkage
        OutStreamer.EmitSymbolAttribute(SymGlob, MCSA_Weak);
      }
    }
  }
  
  void XCoreAsmPrinter::EmitGlobalVariable(const GlobalVariable *GV) {
    // Check to see if this is a special global used by LLVM, if so, emit it.
    if (!GV->hasInitializer() ||
        EmitSpecialLLVMGlobal(GV))
      return;
  
    const DataLayout *TD = TM.getSubtargetImpl()->getDataLayout();
    OutStreamer.SwitchSection(
        getObjFileLowering().SectionForGlobal(GV, *Mang, TM));
  
    MCSymbol *GVSym = getSymbol(GV);
    const Constant *C = GV->getInitializer();
    unsigned Align = (unsigned)TD->getPreferredTypeAlignmentShift(C->getType());
    
    // Mark the start of the global
    getTargetStreamer().emitCCTopData(GVSym->getName());
  
    switch (GV->getLinkage()) {
    case GlobalValue::AppendingLinkage:
      report_fatal_error("AppendingLinkage is not supported by this target!");
    case GlobalValue::LinkOnceAnyLinkage:
    case GlobalValue::LinkOnceODRLinkage:
    case GlobalValue::WeakAnyLinkage:
    case GlobalValue::WeakODRLinkage:
    case GlobalValue::ExternalLinkage:
    case GlobalValue::CommonLinkage:
      emitArrayBound(GVSym, GV);
      OutStreamer.EmitSymbolAttribute(GVSym, MCSA_Global);
  
      // TODO Use COMDAT groups for LinkOnceLinkage
      if (GV->hasWeakLinkage() || GV->hasLinkOnceLinkage() ||
          GV->hasCommonLinkage())
        OutStreamer.EmitSymbolAttribute(GVSym, MCSA_Weak);
      // FALL THROUGH
    case GlobalValue::InternalLinkage:
    case GlobalValue::PrivateLinkage:
      break;
    default:
      llvm_unreachable("Unknown linkage type!");
    }
  
    EmitAlignment(Align > 2 ? Align : 2, GV);
    
    if (GV->isThreadLocal()) {
      report_fatal_error("TLS is not supported by this target!");
    }
    unsigned Size = TD->getTypeAllocSize(C->getType());
    if (MAI->hasDotTypeDotSizeDirective()) {
      OutStreamer.EmitSymbolAttribute(GVSym, MCSA_ELF_TypeObject);
      OutStreamer.EmitELFSize(GVSym, MCConstantExpr::Create(Size, OutContext));
    }
    OutStreamer.EmitLabel(GVSym);
    
    EmitGlobalConstant(C);
    // The ABI requires that unsigned scalar types smaller than 32 bits
    // are padded to 32 bits.
    if (Size < 4)
      OutStreamer.EmitZeros(4 - Size);
    
    // Mark the end of the global
    getTargetStreamer().emitCCBottomData(GVSym->getName());
  }
  
  void XCoreAsmPrinter::EmitFunctionBodyStart() {
    MCInstLowering.Initialize(Mang, &MF->getContext());
  }
  
  /// EmitFunctionBodyEnd - Targets can override this to emit stuff after
  /// the last basic block in the function.
  void XCoreAsmPrinter::EmitFunctionBodyEnd() {
    // Emit function end directives
    getTargetStreamer().emitCCBottomFunction(CurrentFnSym->getName());
  }
  
  void XCoreAsmPrinter::EmitFunctionEntryLabel() {
    // Mark the start of the function
    getTargetStreamer().emitCCTopFunction(CurrentFnSym->getName());
    OutStreamer.EmitLabel(CurrentFnSym);
  }
  
  void XCoreAsmPrinter::
  printInlineJT(const MachineInstr *MI, int opNum, raw_ostream &O,
                const std::string &directive) {
    unsigned JTI = MI->getOperand(opNum).getIndex();
    const MachineFunction *MF = MI->getParent()->getParent();
    const MachineJumpTableInfo *MJTI = MF->getJumpTableInfo();
    const std::vector<MachineJumpTableEntry> &JT = MJTI->getJumpTables();
    const std::vector<MachineBasicBlock*> &JTBBs = JT[JTI].MBBs;
    O << "\t" << directive << " ";
    for (unsigned i = 0, e = JTBBs.size(); i != e; ++i) {
      MachineBasicBlock *MBB = JTBBs[i];
      if (i > 0)
        O << ",";
      O << *MBB->getSymbol();
    }
  }
  
  void XCoreAsmPrinter::printOperand(const MachineInstr *MI, int opNum,
                                     raw_ostream &O) {
    const DataLayout *DL = TM.getSubtargetImpl()->getDataLayout();
    const MachineOperand &MO = MI->getOperand(opNum);
    switch (MO.getType()) {
    case MachineOperand::MO_Register:
      O << XCoreInstPrinter::getRegisterName(MO.getReg());
      break;
    case MachineOperand::MO_Immediate:
      O << MO.getImm();
      break;
    case MachineOperand::MO_MachineBasicBlock:
      O << *MO.getMBB()->getSymbol();
      break;
    case MachineOperand::MO_GlobalAddress:
      O << *getSymbol(MO.getGlobal());
      break;
    case MachineOperand::MO_ConstantPoolIndex:
      O << DL->getPrivateGlobalPrefix() << "CPI" << getFunctionNumber()
        << '_' << MO.getIndex();
      break;
    case MachineOperand::MO_BlockAddress:
      O << *GetBlockAddressSymbol(MO.getBlockAddress());
      break;
    default:
      llvm_unreachable("not implemented");
    }
  }
  
  /// PrintAsmOperand - Print out an operand for an inline asm expression.
  ///
  bool XCoreAsmPrinter::PrintAsmOperand(const MachineInstr *MI, unsigned OpNo,
                                        unsigned AsmVariant,const char *ExtraCode,
                                        raw_ostream &O) {
    // Print the operand if there is no operand modifier.
    if (!ExtraCode || !ExtraCode[0]) {
      printOperand(MI, OpNo, O);
      return false;
    }
  
    // Otherwise fallback on the default implementation.
    return AsmPrinter::PrintAsmOperand(MI, OpNo, AsmVariant, ExtraCode, O);
  }
  
  bool XCoreAsmPrinter::
  PrintAsmMemoryOperand(const MachineInstr *MI, unsigned OpNum,
                        unsigned AsmVariant, const char *ExtraCode,
                        raw_ostream &O) {
    if (ExtraCode && ExtraCode[0]) {
      return true; // Unknown modifier.
    }
    printOperand(MI, OpNum, O);
    O << '[';
    printOperand(MI, OpNum + 1, O);
    O << ']';
    return false;
  }
  
  void XCoreAsmPrinter::EmitInstruction(const MachineInstr *MI) {
    SmallString<128> Str;
    raw_svector_ostream O(Str);
  
    switch (MI->getOpcode()) {
    case XCore::DBG_VALUE:
      llvm_unreachable("Should be handled target independently");
    case XCore::ADD_2rus:
      if (MI->getOperand(2).getImm() == 0) {
        O << "\tmov "
          << XCoreInstPrinter::getRegisterName(MI->getOperand(0).getReg()) << ", "
          << XCoreInstPrinter::getRegisterName(MI->getOperand(1).getReg());
        OutStreamer.EmitRawText(O.str());
        return;
      }
      break;
    case XCore::BR_JT:
    case XCore::BR_JT32:
      O << "\tbru "
        << XCoreInstPrinter::getRegisterName(MI->getOperand(1).getReg()) << '\n';
      if (MI->getOpcode() == XCore::BR_JT)
        printInlineJT(MI, 0, O);
      else
        printInlineJT32(MI, 0, O);
      O << '\n';
      OutStreamer.EmitRawText(O.str());
      return;
    }
  
    MCInst TmpInst;
    MCInstLowering.Lower(MI, TmpInst);
  
    EmitToStreamer(OutStreamer, TmpInst);
  }
  
  // Force static initialization.
  extern "C" void LLVMInitializeXCoreAsmPrinter() { 
    RegisterAsmPrinter<XCoreAsmPrinter> X(TheXCoreTarget);
  }
  