AsmPrinter.cpp

//===-- AsmPrinter.cpp - Common AsmPrinter code ---------------------------===//
//
//                     The LLVM Compiler Infrastructure
//
// This file was developed by the LLVM research group and is distributed under
// the University of Illinois Open Source License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file implements the AsmPrinter class.
//
//===----------------------------------------------------------------------===//

#include "llvm/CodeGen/AsmPrinter.h"
#include "llvm/Assembly/Writer.h"
#include "llvm/DerivedTypes.h"
#include "llvm/Constants.h"
#include "llvm/Module.h"
#include "llvm/CodeGen/MachineConstantPool.h"
#include "llvm/CodeGen/MachineJumpTableInfo.h"
#include "llvm/Support/CommandLine.h"
#include "llvm/Support/Mangler.h"
#include "llvm/Support/MathExtras.h"
#include "llvm/Support/Streams.h"
#include "llvm/Target/TargetAsmInfo.h"
#include "llvm/Target/TargetData.h"
#include "llvm/Target/TargetLowering.h"
#include "llvm/Target/TargetMachine.h"
#include <cerrno>
using namespace llvm;

static cl::opt<bool>
AsmVerbose("asm-verbose", cl::Hidden, cl::desc("Add comments to directives."));

AsmPrinter::AsmPrinter(std::ostream &o, TargetMachine &tm,
                       const TargetAsmInfo *T)
: FunctionNumber(0), O(o), TM(tm), TAI(T)
{}

std::string AsmPrinter::getSectionForFunction(const Function &F) const {
  return TAI->getTextSection();
}


/// SwitchToTextSection - Switch to the specified text section of the executable
/// if we are not already in it!
///
void AsmPrinter::SwitchToTextSection(const char *NewSection,
                                     const GlobalValue *GV) {
  std::string NS;
  if (GV && GV->hasSection())
    NS = TAI->getSwitchToSectionDirective() + GV->getSection();
  else
    NS = NewSection;
  
  // If we're already in this section, we're done.
  if (CurrentSection == NS) return;

  // Close the current section, if applicable.
  if (TAI->getSectionEndDirectiveSuffix() && !CurrentSection.empty())
    O << CurrentSection << TAI->getSectionEndDirectiveSuffix() << "\n";

  CurrentSection = NS;

  if (!CurrentSection.empty())
    O << CurrentSection << TAI->getTextSectionStartSuffix() << '\n';
}

/// SwitchToDataSection - Switch to the specified data section of the executable
/// if we are not already in it!
///
void AsmPrinter::SwitchToDataSection(const char *NewSection,
                                     const GlobalValue *GV) {
  std::string NS;
  if (GV && GV->hasSection())
    NS = TAI->getSwitchToSectionDirective() + GV->getSection();
  else
    NS = NewSection;
  
  // If we're already in this section, we're done.
  if (CurrentSection == NS) return;

  // Close the current section, if applicable.
  if (TAI->getSectionEndDirectiveSuffix() && !CurrentSection.empty())
    O << CurrentSection << TAI->getSectionEndDirectiveSuffix() << "\n";

  CurrentSection = NS;
  
  if (!CurrentSection.empty())
    O << CurrentSection << TAI->getDataSectionStartSuffix() << '\n';
}


bool AsmPrinter::doInitialization(Module &M) {
  Mang = new Mangler(M, TAI->getGlobalPrefix());
  
  if (!M.getModuleInlineAsm().empty())
    O << TAI->getCommentString() << " Start of file scope inline assembly\n"
      << M.getModuleInlineAsm()
      << "\n" << TAI->getCommentString()
      << " End of file scope inline assembly\n";

  SwitchToDataSection("");   // Reset back to no section.
  
  if (MachineModuleInfo *MMI = getAnalysisToUpdate<MachineModuleInfo>()) {
    MMI->AnalyzeModule(M);
  }
  
  return false;
}

bool AsmPrinter::doFinalization(Module &M) {
  if (TAI->getWeakRefDirective()) {
    if (ExtWeakSymbols.begin() != ExtWeakSymbols.end())
      SwitchToDataSection("");

    for (std::set<const GlobalValue*>::iterator i = ExtWeakSymbols.begin(),
         e = ExtWeakSymbols.end(); i != e; ++i) {
      const GlobalValue *GV = *i;
      std::string Name = Mang->getValueName(GV);
      O << TAI->getWeakRefDirective() << Name << "\n";
    }
  }

  delete Mang; Mang = 0;
  return false;
}

void AsmPrinter::SetupMachineFunction(MachineFunction &MF) {
  // What's my mangled name?
  CurrentFnName = Mang->getValueName(MF.getFunction());
  IncrementFunctionNumber();
}

/// EmitConstantPool - Print to the current output stream assembly
/// representations of the constants in the constant pool MCP. This is
/// used to print out constants which have been "spilled to memory" by
/// the code generator.
///
void AsmPrinter::EmitConstantPool(MachineConstantPool *MCP) {
  const std::vector<MachineConstantPoolEntry> &CP = MCP->getConstants();
  if (CP.empty()) return;

  // Some targets require 4-, 8-, and 16- byte constant literals to be placed
  // in special sections.
  std::vector<std::pair<MachineConstantPoolEntry,unsigned> > FourByteCPs;
  std::vector<std::pair<MachineConstantPoolEntry,unsigned> > EightByteCPs;
  std::vector<std::pair<MachineConstantPoolEntry,unsigned> > SixteenByteCPs;
  std::vector<std::pair<MachineConstantPoolEntry,unsigned> > OtherCPs;
  std::vector<std::pair<MachineConstantPoolEntry,unsigned> > TargetCPs;
  for (unsigned i = 0, e = CP.size(); i != e; ++i) {
    MachineConstantPoolEntry CPE = CP[i];
    const Type *Ty = CPE.getType();
    if (TAI->getFourByteConstantSection() &&
        TM.getTargetData()->getTypeSize(Ty) == 4)
      FourByteCPs.push_back(std::make_pair(CPE, i));
    else if (TAI->getEightByteConstantSection() &&
             TM.getTargetData()->getTypeSize(Ty) == 8)
      EightByteCPs.push_back(std::make_pair(CPE, i));
    else if (TAI->getSixteenByteConstantSection() &&
             TM.getTargetData()->getTypeSize(Ty) == 16)
      SixteenByteCPs.push_back(std::make_pair(CPE, i));
    else
      OtherCPs.push_back(std::make_pair(CPE, i));
  }

  unsigned Alignment = MCP->getConstantPoolAlignment();
  EmitConstantPool(Alignment, TAI->getFourByteConstantSection(), FourByteCPs);
  EmitConstantPool(Alignment, TAI->getEightByteConstantSection(), EightByteCPs);
  EmitConstantPool(Alignment, TAI->getSixteenByteConstantSection(),
                   SixteenByteCPs);
  EmitConstantPool(Alignment, TAI->getConstantPoolSection(), OtherCPs);
}

void AsmPrinter::EmitConstantPool(unsigned Alignment, const char *Section,
               std::vector<std::pair<MachineConstantPoolEntry,unsigned> > &CP) {
  if (CP.empty()) return;

  SwitchToDataSection(Section);
  EmitAlignment(Alignment);
  for (unsigned i = 0, e = CP.size(); i != e; ++i) {
    O << TAI->getPrivateGlobalPrefix() << "CPI" << getFunctionNumber() << '_'
      << CP[i].second << ":\t\t\t\t\t" << TAI->getCommentString() << " ";
    WriteTypeSymbolic(O, CP[i].first.getType(), 0) << '\n';
    if (CP[i].first.isMachineConstantPoolEntry())
      EmitMachineConstantPoolValue(CP[i].first.Val.MachineCPVal);
     else
      EmitGlobalConstant(CP[i].first.Val.ConstVal);
    if (i != e-1) {
      const Type *Ty = CP[i].first.getType();
      unsigned EntSize =
        TM.getTargetData()->getTypeSize(Ty);
      unsigned ValEnd = CP[i].first.getOffset() + EntSize;
      // Emit inter-object padding for alignment.
      EmitZeros(CP[i+1].first.getOffset()-ValEnd);
    }
  }
}

/// EmitJumpTableInfo - Print assembly representations of the jump tables used