lib/MC/MCObjectStreamer.cpp

//===- lib/MC/MCObjectStreamer.cpp - Object File MCStreamer Interface -----===//
//
//                     The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//

#include "llvm/MC/MCObjectStreamer.h"

#include "llvm/Support/ErrorHandling.h"
#include "llvm/MC/MCAssembler.h"
#include "llvm/MC/MCCodeEmitter.h"
#include "llvm/MC/MCExpr.h"
#include "llvm/Target/TargetAsmBackend.h"
using namespace llvm;

MCObjectStreamer::MCObjectStreamer(MCContext &Context, TargetAsmBackend &TAB,
                                   raw_ostream &_OS, MCCodeEmitter *_Emitter,
                                   bool _PadSectionToAlignment)
  : MCStreamer(Context), Assembler(new MCAssembler(Context, TAB,
                                                   *_Emitter,
                                                   _PadSectionToAlignment,
                                                   _OS)),
    CurSectionData(0)
{
}

MCObjectStreamer::~MCObjectStreamer() {
  delete &Assembler->getBackend();
  delete &Assembler->getEmitter();
  delete Assembler;
}

MCFragment *MCObjectStreamer::getCurrentFragment() const {
  assert(getCurrentSectionData() && "No current section!");

  if (!getCurrentSectionData()->empty())
    return &getCurrentSectionData()->getFragmentList().back();

  return 0;
}

MCDataFragment *MCObjectStreamer::getOrCreateDataFragment() const {
  MCDataFragment *F = dyn_cast_or_null<MCDataFragment>(getCurrentFragment());
  if (!F)
    F = new MCDataFragment(getCurrentSectionData());
  return F;
}

const MCExpr *MCObjectStreamer::AddValueSymbols(const MCExpr *Value) {
  switch (Value->getKind()) {
  case MCExpr::Target: llvm_unreachable("Can't handle target exprs yet!");
  case MCExpr::Constant:
    break;

  case MCExpr::Binary: {
    const MCBinaryExpr *BE = cast<MCBinaryExpr>(Value);
    AddValueSymbols(BE->getLHS());
    AddValueSymbols(BE->getRHS());
    break;
  }

  case MCExpr::SymbolRef:
    Assembler->getOrCreateSymbolData(cast<MCSymbolRefExpr>(Value)->getSymbol());
    break;

  case MCExpr::Unary:
    AddValueSymbols(cast<MCUnaryExpr>(Value)->getSubExpr());
    break;
  }

  return Value;
}

void MCObjectStreamer::EmitWeakReference(MCSymbol *Alias,
                                         const MCSymbol *Symbol) {
  report_fatal_error("This file format doesn't support weak aliases.");
}

void MCObjectStreamer::SwitchSection(const MCSection *Section) {
  assert(Section && "Cannot switch to a null section!");

  // If already in this section, then this is a noop.
  if (Section == CurSection) return;

  PrevSection = CurSection;
  CurSection = Section;
  CurSectionData = &getAssembler().getOrCreateSectionData(*Section);
}

void MCObjectStreamer::Finish() {
  getAssembler().Finish();
}