AsmPrinter.cpp

//===-- AsmPrinter.cpp - Common AsmPrinter code ---------------------------===//
//
//                     The LLVM Compiler Infrastructure
//
// This file 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/CodeGen/MachineModuleInfo.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 "llvm/ADT/SmallPtrSet.h"
#include <cerrno>
using namespace llvm;

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

char AsmPrinter::ID = 0;
AsmPrinter::AsmPrinter(std::ostream &o, TargetMachine &tm,
                       const TargetAsmInfo *T)
  : MachineFunctionPass((intptr_t)&ID), 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.empty())
      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";
    }
  }

  if (TAI->getSetDirective()) {
    if (!M.alias_empty())
      SwitchToTextSection(TAI->getTextSection());

    O << "\n";
    for (Module::const_alias_iterator I = M.alias_begin(), E = M.alias_end();
         I!=E; ++I) {
      std::string Name = Mang->getValueName(I);
      std::string Target;

      const GlobalValue *GV = cast<GlobalValue>(I->getAliasedGlobal());
      Target = Mang->getValueName(GV);
      
      if (I->hasExternalLinkage() || !TAI->getWeakRefDirective())
        O << "\t.globl\t" << Name << "\n";
      else if (I->hasWeakLinkage())
        O << TAI->getWeakRefDirective() << Name << "\n";
      else if (!I->hasInternalLinkage())
        assert(0 && "Invalid alias linkage");
      
      O << TAI->getSetDirective() << Name << ", " << Target << "\n";

      // If the aliasee has external weak linkage it can be referenced only by
      // alias itself. In this case it can be not in ExtWeakSymbols list. Emit
      // weak reference in such case.
      if (GV->hasExternalWeakLinkage())
        if (TAI->getWeakRefDirective())
          O << TAI->getWeakRefDirective() << Target << "\n";
        else
          O << "\t.globl\t" << Target << "\n";
    }
  }

  delete Mang; Mang = 0;
  return false;
}

std::string AsmPrinter::getCurrentFunctionEHName(const MachineFunction *MF) {
  assert(MF && "No machine function?");
  return Mang->makeNameProper(MF->getFunction()->getName() + ".eh",
                              TAI->getGlobalPrefix());
}

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()->getABITypeSize(Ty) == 4)
      FourByteCPs.push_back(std::make_pair(CPE, i));
    else if (TAI->getEightByteConstantSection() &&
             TM.getTargetData()->getABITypeSize(Ty) == 8)