AsmPrinter.cpp

//
//                     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.
//
//===----------------------------------------------------------------------===//

#define DEBUG_TYPE "asm-printer"
#include "llvm/CodeGen/AsmPrinter.h"
#include "DwarfDebug.h"
#include "DwarfException.h"
#include "llvm/Module.h"
#include "llvm/CodeGen/GCMetadataPrinter.h"
#include "llvm/CodeGen/MachineConstantPool.h"
#include "llvm/CodeGen/MachineFrameInfo.h"
#include "llvm/CodeGen/MachineFunction.h"
#include "llvm/CodeGen/MachineJumpTableInfo.h"
#include "llvm/CodeGen/MachineLoopInfo.h"
#include "llvm/CodeGen/MachineModuleInfo.h"
#include "llvm/Analysis/ConstantFolding.h"
#include "llvm/Analysis/DebugInfo.h"
#include "llvm/MC/MCAsmInfo.h"
#include "llvm/MC/MCContext.h"
#include "llvm/MC/MCExpr.h"
#include "llvm/MC/MCInst.h"
#include "llvm/MC/MCSection.h"
#include "llvm/MC/MCStreamer.h"
#include "llvm/MC/MCSymbol.h"
#include "llvm/Target/Mangler.h"
#include "llvm/Target/TargetData.h"
#include "llvm/Target/TargetInstrInfo.h"
#include "llvm/Target/TargetLowering.h"
#include "llvm/Target/TargetLoweringObjectFile.h"
#include "llvm/Target/TargetRegisterInfo.h"
#include "llvm/ADT/SmallString.h"
#include "llvm/ADT/Statistic.h"
#include "llvm/Support/ErrorHandling.h"
#include "llvm/Support/Format.h"
#include "llvm/Support/Timer.h"
using namespace llvm;

namespace {
  const char *DWARFGroupName = "DWARF Emission";
  const char *DbgTimerName = "DWARF Debug Writer";
  const char *EHTimerName = "DWARF Exception Writer";
} // end anonymous namespace

STATISTIC(EmittedInsts, "Number of machine instrs printed");

char AsmPrinter::ID = 0;

typedef DenseMap<GCStrategy*,GCMetadataPrinter*> gcp_map_type;
static gcp_map_type &getGCMap(void *&P) {
  if (P == 0)
    P = new gcp_map_type();
  return *(gcp_map_type*)P;
}


AsmPrinter::AsmPrinter(TargetMachine &tm, MCStreamer &Streamer)
  : MachineFunctionPass(&ID),
    TM(tm), MAI(tm.getMCAsmInfo()),
    OutContext(Streamer.getContext()),
    OutStreamer(Streamer),
    LastMI(0), LastFn(0), Counter(~0U), SetCounter(0) {
  DD = 0; DE = 0; MMI = 0; LI = 0;
  GCMetadataPrinters = 0;
  VerboseAsm = Streamer.isVerboseAsm();
}

AsmPrinter::~AsmPrinter() {
  assert(DD == 0 && DE == 0 && "Debug/EH info didn't get finalized");
  
  if (GCMetadataPrinters != 0) {
    gcp_map_type &GCMap = getGCMap(GCMetadataPrinters);
    
    for (gcp_map_type::iterator I = GCMap.begin(), E = GCMap.end(); I != E; ++I)
      delete I->second;
    delete &GCMap;
    GCMetadataPrinters = 0;
  }
  
  delete &OutStreamer;
}

/// getFunctionNumber - Return a unique ID for the current function.
///
unsigned AsmPrinter::getFunctionNumber() const {
  return MF->getFunctionNumber();
}

TargetLoweringObjectFile &AsmPrinter::getObjFileLowering() const {
  return TM.getTargetLowering()->getObjFileLowering();
}


/// getTargetData - Return information about data layout.
const TargetData &AsmPrinter::getTargetData() const {
  return *TM.getTargetData();
}

/// getCurrentSection() - Return the current section we are emitting to.
const MCSection *AsmPrinter::getCurrentSection() const {
  return OutStreamer.getCurrentSection();
}



void AsmPrinter::getAnalysisUsage(AnalysisUsage &AU) const {
  AU.setPreservesAll();
  MachineFunctionPass::getAnalysisUsage(AU);
  AU.addRequired<MachineModuleInfo>();
  AU.addRequired<GCModuleInfo>();
  if (isVerbose())
    AU.addRequired<MachineLoopInfo>();
}

bool AsmPrinter::doInitialization(Module &M) {
  MMI = getAnalysisIfAvailable<MachineModuleInfo>();
  MMI->AnalyzeModule(M);

  // Initialize TargetLoweringObjectFile.
  const_cast<TargetLoweringObjectFile&>(getObjFileLowering())
    .Initialize(OutContext, TM);
  
  Mang = new Mangler(OutContext, *TM.getTargetData());
  
  // Allow the target to emit any magic that it wants at the start of the file.
  EmitStartOfAsmFile(M);

  // Very minimal debug info. It is ignored if we emit actual debug info. If we
  // don't, this at least helps the user find where a global came from.
  if (MAI->hasSingleParameterDotFile()) {
    // .file "foo.c"
    OutStreamer.EmitFileDirective(M.getModuleIdentifier());
  }

  GCModuleInfo *MI = getAnalysisIfAvailable<GCModuleInfo>();
  assert(MI && "AsmPrinter didn't require GCModuleInfo?");
  for (GCModuleInfo::iterator I = MI->begin(), E = MI->end(); I != E; ++I)
    if (GCMetadataPrinter *MP = GetOrCreateGCPrinter(*I))
      MP->beginAssembly(*this);

  // Emit module-level inline asm if it exists.
  if (!M.getModuleInlineAsm().empty()) {
    OutStreamer.AddComment("Start of file scope inline assembly");
    OutStreamer.AddBlankLine();
    EmitInlineAsm(M.getModuleInlineAsm(), 0/*no loc cookie*/);
    OutStreamer.AddComment("End of file scope inline assembly");
    OutStreamer.AddBlankLine();
  }

  if (MAI->doesSupportDebugInformation())
    DD = new DwarfDebug(this, &M);
    
  if (MAI->doesSupportExceptionHandling())
    DE = new DwarfException(this);

  return false;
}

void AsmPrinter::EmitLinkage(unsigned Linkage, MCSymbol *GVSym) const {
  switch ((GlobalValue::LinkageTypes)Linkage) {
  case GlobalValue::CommonLinkage:
  case GlobalValue::LinkOnceAnyLinkage:
  case GlobalValue::LinkOnceODRLinkage:
  case GlobalValue::WeakAnyLinkage:
  case GlobalValue::WeakODRLinkage:
  case GlobalValue::LinkerPrivateLinkage:
    if (MAI->getWeakDefDirective() != 0) {
      // .globl _foo
      OutStreamer.EmitSymbolAttribute(GVSym, MCSA_Global);
      // .weak_definition _foo
      OutStreamer.EmitSymbolAttribute(GVSym, MCSA_WeakDefinition);
    } else if (const char *LinkOnce = MAI->getLinkOnceDirective()) {
      // .globl _foo
      OutStreamer.EmitSymbolAttribute(GVSym, MCSA_Global);
      // FIXME: linkonce should be a section attribute, handled by COFF Section
      // assignment.
      // http://sourceware.org/binutils/docs-2.20/as/Linkonce.html#Linkonce
      // .linkonce discard
      // FIXME: It would be nice to use .linkonce samesize for non-common
      // globals.
      OutStreamer.EmitRawText(StringRef(LinkOnce));
    } else {
      // .weak _foo
      OutStreamer.EmitSymbolAttribute(GVSym, MCSA_Weak);
    }
    break;
  case GlobalValue::DLLExportLinkage:
  case GlobalValue::AppendingLinkage:
    // FIXME: appending linkage variables should go into a section of
    // their name or something.  For now, just emit them as external.
  case GlobalValue::ExternalLinkage:
    // If external or appending, declare as a global symbol.