llvm-project/llvm/lib/MC/WinCOFFStreamer.cpp

350 lines
13 KiB
C++

//===-- llvm/MC/WinCOFFStreamer.cpp -----------------------------*- C++ -*-===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file contains an implementation of a Win32 COFF object file streamer.
//
//===----------------------------------------------------------------------===//
#define DEBUG_TYPE "WinCOFFStreamer"
#include "llvm/MC/MCObjectStreamer.h"
#include "llvm/MC/MCContext.h"
#include "llvm/MC/MCSection.h"
#include "llvm/MC/MCSymbol.h"
#include "llvm/MC/MCExpr.h"
#include "llvm/MC/MCValue.h"
#include "llvm/MC/MCAssembler.h"
#include "llvm/MC/MCAsmLayout.h"
#include "llvm/MC/MCCodeEmitter.h"
#include "llvm/MC/MCSectionCOFF.h"
#include "llvm/Target/TargetRegistry.h"
#include "llvm/Target/TargetAsmBackend.h"
#include "llvm/ADT/StringMap.h"
#include "llvm/Support/COFF.h"
#include "llvm/Support/Debug.h"
#include "llvm/Support/ErrorHandling.h"
#include "llvm/Support/raw_ostream.h"
using namespace llvm;
namespace {
class WinCOFFStreamer : public MCObjectStreamer {
public:
MCSymbol const *CurSymbol;
WinCOFFStreamer(MCContext &Context,
TargetAsmBackend &TAB,
MCCodeEmitter &CE,
raw_ostream &OS);
void AddCommonSymbol(MCSymbol *Symbol, uint64_t Size,
unsigned ByteAlignment, bool External);
// MCStreamer interface
virtual void EmitLabel(MCSymbol *Symbol);
virtual void EmitAssemblerFlag(MCAssemblerFlag Flag);
virtual void EmitAssignment(MCSymbol *Symbol, const MCExpr *Value);
virtual void EmitSymbolAttribute(MCSymbol *Symbol, MCSymbolAttr Attribute);
virtual void EmitSymbolDesc(MCSymbol *Symbol, unsigned DescValue);
virtual void BeginCOFFSymbolDef(MCSymbol const *Symbol);
virtual void EmitCOFFSymbolStorageClass(int StorageClass);
virtual void EmitCOFFSymbolType(int Type);
virtual void EndCOFFSymbolDef();
virtual void EmitELFSize(MCSymbol *Symbol, const MCExpr *Value);
virtual void EmitCommonSymbol(MCSymbol *Symbol, uint64_t Size,
unsigned ByteAlignment);
virtual void EmitLocalCommonSymbol(MCSymbol *Symbol, uint64_t Size);
virtual void EmitZerofill(const MCSection *Section, MCSymbol *Symbol,
unsigned Size,unsigned ByteAlignment);
virtual void EmitTBSSSymbol(const MCSection *Section, MCSymbol *Symbol,
uint64_t Size, unsigned ByteAlignment);
virtual void EmitBytes(StringRef Data, unsigned AddrSpace);
virtual void EmitValue(const MCExpr *Value, unsigned Size,
unsigned AddrSpace);
virtual void EmitGPRel32Value(const MCExpr *Value);
virtual void EmitValueToAlignment(unsigned ByteAlignment, int64_t Value,
unsigned ValueSize, unsigned MaxBytesToEmit);
virtual void EmitCodeAlignment(unsigned ByteAlignment,
unsigned MaxBytesToEmit);
virtual void EmitValueToOffset(const MCExpr *Offset, unsigned char Value);
virtual void EmitFileDirective(StringRef Filename);
virtual void EmitDwarfFileDirective(unsigned FileNo,StringRef Filename);
virtual void EmitInstruction(const MCInst &Instruction);
virtual void Finish();
};
} // end anonymous namespace.
WinCOFFStreamer::WinCOFFStreamer(MCContext &Context,
TargetAsmBackend &TAB,
MCCodeEmitter &CE,
raw_ostream &OS)
: MCObjectStreamer(Context, TAB, OS, &CE)
, CurSymbol(NULL) {
}
void WinCOFFStreamer::AddCommonSymbol(MCSymbol *Symbol, uint64_t Size,
unsigned ByteAlignment, bool External) {
assert(!Symbol->isInSection() && "Symbol must not already have a section!");
std::string SectionName(".bss$linkonce");
SectionName.append(Symbol->getName().begin(), Symbol->getName().end());
MCSymbolData &SymbolData = getAssembler().getOrCreateSymbolData(*Symbol);
unsigned Characteristics =
COFF::IMAGE_SCN_LNK_COMDAT |
COFF::IMAGE_SCN_CNT_UNINITIALIZED_DATA |
COFF::IMAGE_SCN_MEM_READ |
COFF::IMAGE_SCN_MEM_WRITE;
int Selection = COFF::IMAGE_COMDAT_SELECT_LARGEST;
const MCSection *Section = MCStreamer::getContext().getCOFFSection(
SectionName, Characteristics, Selection, SectionKind::getBSS());
MCSectionData &SectionData = getAssembler().getOrCreateSectionData(*Section);
if (SectionData.getAlignment() < ByteAlignment)
SectionData.setAlignment(ByteAlignment);
SymbolData.setExternal(External);
Symbol->setSection(*Section);
if (ByteAlignment != 1)
new MCAlignFragment(ByteAlignment, 0, 0, ByteAlignment, &SectionData);
SymbolData.setFragment(new MCFillFragment(0, 0, Size, &SectionData));
}
// MCStreamer interface
void WinCOFFStreamer::EmitLabel(MCSymbol *Symbol) {
// TODO: This is copied almost exactly from the MachOStreamer. Consider
// merging into MCObjectStreamer?
assert(Symbol->isUndefined() && "Cannot define a symbol twice!");
assert(!Symbol->isVariable() && "Cannot emit a variable symbol!");
assert(CurSection && "Cannot emit before setting section!");
Symbol->setSection(*CurSection);
MCSymbolData &SD = getAssembler().getOrCreateSymbolData(*Symbol);
// FIXME: This is wasteful, we don't necessarily need to create a data
// fragment. Instead, we should mark the symbol as pointing into the data
// fragment if it exists, otherwise we should just queue the label and set its
// fragment pointer when we emit the next fragment.
MCDataFragment *DF = getOrCreateDataFragment();
assert(!SD.getFragment() && "Unexpected fragment on symbol data!");
SD.setFragment(DF);
SD.setOffset(DF->getContents().size());
}
void WinCOFFStreamer::EmitAssemblerFlag(MCAssemblerFlag Flag) {
llvm_unreachable("not implemented");
}
void WinCOFFStreamer::EmitAssignment(MCSymbol *Symbol, const MCExpr *Value) {
// TODO: This is exactly the same as MachOStreamer. Consider merging into
// MCObjectStreamer.
getAssembler().getOrCreateSymbolData(*Symbol);
AddValueSymbols(Value);
Symbol->setVariableValue(Value);
}
void WinCOFFStreamer::EmitSymbolAttribute(MCSymbol *Symbol,
MCSymbolAttr Attribute) {
switch (Attribute) {
case MCSA_WeakReference:
getAssembler().getOrCreateSymbolData(*Symbol).modifyFlags(
COFF::SF_WeakReference,
COFF::SF_WeakReference);
break;
case MCSA_Global:
getAssembler().getOrCreateSymbolData(*Symbol).setExternal(true);
break;
default:
llvm_unreachable("unsupported attribute");
break;
}
}
void WinCOFFStreamer::EmitSymbolDesc(MCSymbol *Symbol, unsigned DescValue) {
llvm_unreachable("not implemented");
}
void WinCOFFStreamer::BeginCOFFSymbolDef(MCSymbol const *Symbol) {
assert(CurSymbol == NULL && "EndCOFFSymbolDef must be called between calls "
"to BeginCOFFSymbolDef!");
CurSymbol = Symbol;
}
void WinCOFFStreamer::EmitCOFFSymbolStorageClass(int StorageClass) {
assert(CurSymbol != NULL && "BeginCOFFSymbolDef must be called first!");
assert((StorageClass & ~0xFF) == 0 && "StorageClass must only have data in "
"the first byte!");
getAssembler().getOrCreateSymbolData(*CurSymbol).modifyFlags(
StorageClass << COFF::SF_ClassShift,
COFF::SF_ClassMask);
}
void WinCOFFStreamer::EmitCOFFSymbolType(int Type) {
assert(CurSymbol != NULL && "BeginCOFFSymbolDef must be called first!");
assert((Type & ~0xFFFF) == 0 && "Type must only have data in the first 2 "
"bytes");
getAssembler().getOrCreateSymbolData(*CurSymbol).modifyFlags(
Type << COFF::SF_TypeShift,
COFF::SF_TypeMask);
}
void WinCOFFStreamer::EndCOFFSymbolDef() {
assert(CurSymbol != NULL && "BeginCOFFSymbolDef must be called first!");
CurSymbol = NULL;
}
void WinCOFFStreamer::EmitELFSize(MCSymbol *Symbol, const MCExpr *Value) {
llvm_unreachable("not implemented");
}
void WinCOFFStreamer::EmitCommonSymbol(MCSymbol *Symbol, uint64_t Size,
unsigned ByteAlignment) {
AddCommonSymbol(Symbol, Size, ByteAlignment, true);
}
void WinCOFFStreamer::EmitLocalCommonSymbol(MCSymbol *Symbol, uint64_t Size) {
AddCommonSymbol(Symbol, Size, 1, false);
}
void WinCOFFStreamer::EmitZerofill(const MCSection *Section, MCSymbol *Symbol,
unsigned Size,unsigned ByteAlignment) {
llvm_unreachable("not implemented");
}
void WinCOFFStreamer::EmitTBSSSymbol(const MCSection *Section, MCSymbol *Symbol,
uint64_t Size, unsigned ByteAlignment) {
llvm_unreachable("not implemented");
}
void WinCOFFStreamer::EmitBytes(StringRef Data, unsigned AddrSpace) {
// TODO: This is copied exactly from the MachOStreamer. Consider merging into
// MCObjectStreamer?
getOrCreateDataFragment()->getContents().append(Data.begin(), Data.end());
}
void WinCOFFStreamer::EmitValue(const MCExpr *Value, unsigned Size,
unsigned AddrSpace) {
assert(AddrSpace == 0 && "Address space must be 0!");
// TODO: This is copied exactly from the MachOStreamer. Consider merging into
// MCObjectStreamer?
MCDataFragment *DF = getOrCreateDataFragment();
// Avoid fixups when possible.
int64_t AbsValue;
if (AddValueSymbols(Value)->EvaluateAsAbsolute(AbsValue)) {
// FIXME: Endianness assumption.
for (unsigned i = 0; i != Size; ++i)
DF->getContents().push_back(uint8_t(AbsValue >> (i * 8)));
} else {
DF->addFixup(MCFixup::Create(DF->getContents().size(),
AddValueSymbols(Value),
MCFixup::getKindForSize(Size)));
DF->getContents().resize(DF->getContents().size() + Size, 0);
}
}
void WinCOFFStreamer::EmitGPRel32Value(const MCExpr *Value) {
llvm_unreachable("not implemented");
}
void WinCOFFStreamer::EmitValueToAlignment(unsigned ByteAlignment,
int64_t Value,
unsigned ValueSize,
unsigned MaxBytesToEmit) {
// TODO: This is copied exactly from the MachOStreamer. Consider merging into
// MCObjectStreamer?
if (MaxBytesToEmit == 0)
MaxBytesToEmit = ByteAlignment;
new MCAlignFragment(ByteAlignment, Value, ValueSize, MaxBytesToEmit,
getCurrentSectionData());
// Update the maximum alignment on the current section if necessary.
if (ByteAlignment > getCurrentSectionData()->getAlignment())
getCurrentSectionData()->setAlignment(ByteAlignment);
}
void WinCOFFStreamer::EmitCodeAlignment(unsigned ByteAlignment,
unsigned MaxBytesToEmit) {
// TODO: This is copied exactly from the MachOStreamer. Consider merging into
// MCObjectStreamer?
if (MaxBytesToEmit == 0)
MaxBytesToEmit = ByteAlignment;
MCAlignFragment *F = new MCAlignFragment(ByteAlignment, 0, 1, MaxBytesToEmit,
getCurrentSectionData());
F->setEmitNops(true);
// Update the maximum alignment on the current section if necessary.
if (ByteAlignment > getCurrentSectionData()->getAlignment())
getCurrentSectionData()->setAlignment(ByteAlignment);
}
void WinCOFFStreamer::EmitValueToOffset(const MCExpr *Offset,
unsigned char Value) {
llvm_unreachable("not implemented");
}
void WinCOFFStreamer::EmitFileDirective(StringRef Filename) {
// Ignore for now, linkers don't care, and proper debug
// info will be a much large effort.
}
void WinCOFFStreamer::EmitDwarfFileDirective(unsigned FileNo,
StringRef Filename) {
llvm_unreachable("not implemented");
}
void WinCOFFStreamer::EmitInstruction(const MCInst &Instruction) {
for (unsigned i = 0, e = Instruction.getNumOperands(); i != e; ++i)
if (Instruction.getOperand(i).isExpr())
AddValueSymbols(Instruction.getOperand(i).getExpr());
getCurrentSectionData()->setHasInstructions(true);
MCInstFragment *Fragment =
new MCInstFragment(Instruction, getCurrentSectionData());
raw_svector_ostream VecOS(Fragment->getCode());
getAssembler().getEmitter().EncodeInstruction(Instruction, VecOS,
Fragment->getFixups());
}
void WinCOFFStreamer::Finish() {
MCObjectStreamer::Finish();
}
namespace llvm
{
MCStreamer *createWinCOFFStreamer(MCContext &Context,
TargetAsmBackend &TAB,
MCCodeEmitter &CE,
raw_ostream &OS,
bool RelaxAll) {
WinCOFFStreamer *S = new WinCOFFStreamer(Context, TAB, CE, OS);
S->getAssembler().setRelaxAll(RelaxAll);
return S;
}
}