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//===- lib/MC/MCPureStreamer.cpp - MC "Pure" Object Output ----------------===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
#include "llvm/MC/MCStreamer.h"
#include "llvm/MC/MCAssembler.h"
#include "llvm/MC/MCCodeEmitter.h"
#include "llvm/MC/MCContext.h"
#include "llvm/MC/MCExpr.h"
#include "llvm/MC/MCObjectStreamer.h"
// FIXME: Remove this.
#include "llvm/MC/MCSectionMachO.h"
#include "llvm/MC/MCSymbol.h"
#include "llvm/Support/ErrorHandling.h"
using namespace llvm;
namespace {
class MCPureStreamer : public MCObjectStreamer {
private:
virtual void EmitInstToFragment(const MCInst &Inst);
virtual void EmitInstToData(const MCInst &Inst);
public:
MCPureStreamer(MCContext &Context, MCAsmBackend &TAB,
raw_ostream &OS, MCCodeEmitter *Emitter)
: MCObjectStreamer(Context, TAB, OS, Emitter) {}
/// @name MCStreamer Interface
/// @{
virtual void InitSections();
virtual void EmitLabel(MCSymbol *Symbol);
virtual void EmitZerofill(const MCSection *Section, MCSymbol *Symbol = 0,
uint64_t Size = 0, unsigned ByteAlignment = 0);
virtual void EmitBytes(StringRef Data, unsigned AddrSpace);
virtual void EmitValueToAlignment(unsigned ByteAlignment, int64_t Value = 0,
unsigned ValueSize = 1,
unsigned MaxBytesToEmit = 0);
virtual void EmitCodeAlignment(unsigned ByteAlignment,
unsigned MaxBytesToEmit = 0);
virtual bool EmitValueToOffset(const MCExpr *Offset,
unsigned char Value = 0);
virtual void FinishImpl();
virtual void EmitSymbolAttribute(MCSymbol *Symbol, MCSymbolAttr Attribute) {
report_fatal_error("unsupported directive in pure streamer");
}
virtual void EmitAssemblerFlag(MCAssemblerFlag Flag) {
report_fatal_error("unsupported directive in pure streamer");
}
virtual void EmitTBSSSymbol(const MCSection *Section, MCSymbol *Symbol,
uint64_t Size, unsigned ByteAlignment = 0) {
report_fatal_error("unsupported directive in pure streamer");
}
virtual void EmitSymbolDesc(MCSymbol *Symbol, unsigned DescValue) {
report_fatal_error("unsupported directive in pure streamer");
}
virtual void EmitCommonSymbol(MCSymbol *Symbol, uint64_t Size,
unsigned ByteAlignment) {
report_fatal_error("unsupported directive in pure streamer");
}
virtual void EmitThumbFunc(MCSymbol *Func) {
report_fatal_error("unsupported directive in pure streamer");
}
virtual void BeginCOFFSymbolDef(const MCSymbol *Symbol) {
report_fatal_error("unsupported directive in pure streamer");
}
virtual void EmitCOFFSymbolStorageClass(int StorageClass) {
report_fatal_error("unsupported directive in pure streamer");
}
virtual void EmitCOFFSymbolType(int Type) {
report_fatal_error("unsupported directive in pure streamer");
}
virtual void EndCOFFSymbolDef() {
report_fatal_error("unsupported directive in pure streamer");
}
virtual void EmitELFSize(MCSymbol *Symbol, const MCExpr *Value) {
report_fatal_error("unsupported directive in pure streamer");
}
virtual void EmitLocalCommonSymbol(MCSymbol *Symbol, uint64_t Size,
unsigned ByteAlignment) {
report_fatal_error("unsupported directive in pure streamer");
}
virtual void EmitFileDirective(StringRef Filename) {
report_fatal_error("unsupported directive in pure streamer");
}
virtual bool EmitDwarfFileDirective(unsigned FileNo, StringRef Directory,
StringRef Filename) {
report_fatal_error("unsupported directive in pure streamer");
}
/// @}
};
} // end anonymous namespace.
void MCPureStreamer::InitSections() {
// FIMXE: To what!?
SwitchSection(getContext().getMachOSection("__TEXT", "__text",
MCSectionMachO::S_ATTR_PURE_INSTRUCTIONS,
0, SectionKind::getText()));
}
void MCPureStreamer::EmitLabel(MCSymbol *Symbol) {
assert(Symbol->isUndefined() && "Cannot define a symbol twice!");
assert(!Symbol->isVariable() && "Cannot emit a variable symbol!");
assert(getCurrentSection() && "Cannot emit before setting section!");
Symbol->setSection(*getCurrentSection());
MCSymbolData &SD = getAssembler().getOrCreateSymbolData(*Symbol);
// We have to create a new fragment if this is an atom defining symbol,
// fragments cannot span atoms.
if (getAssembler().isSymbolLinkerVisible(SD.getSymbol()))
new MCDataFragment(getCurrentSectionData());
// 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 *F = getOrCreateDataFragment();
assert(!SD.getFragment() && "Unexpected fragment on symbol data!");
SD.setFragment(F);
SD.setOffset(F->getContents().size());
}
void MCPureStreamer::EmitZerofill(const MCSection *Section, MCSymbol *Symbol,
uint64_t Size, unsigned ByteAlignment) {
report_fatal_error("not yet implemented in pure streamer");
}
void MCPureStreamer::EmitBytes(StringRef Data, unsigned AddrSpace) {
// TODO: This is exactly the same as WinCOFFStreamer. Consider merging into
// MCObjectStreamer.
getOrCreateDataFragment()->getContents().append(Data.begin(), Data.end());
}
void MCPureStreamer::EmitValueToAlignment(unsigned ByteAlignment,
int64_t Value, unsigned ValueSize,
unsigned MaxBytesToEmit) {
// TODO: This is exactly the same as WinCOFFStreamer. 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 MCPureStreamer::EmitCodeAlignment(unsigned ByteAlignment,
unsigned MaxBytesToEmit) {
// TODO: This is exactly the same as WinCOFFStreamer. 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);
}
bool MCPureStreamer::EmitValueToOffset(const MCExpr *Offset,
unsigned char Value) {
new MCOrgFragment(*Offset, Value, getCurrentSectionData());
return false;
}
void MCPureStreamer::EmitInstToFragment(const MCInst &Inst) {
MCInstFragment *IF = new MCInstFragment(Inst, getCurrentSectionData());
// Add the fixups and data.
//
// FIXME: Revisit this design decision when relaxation is done, we may be
// able to get away with not storing any extra data in the MCInst.
SmallVector<MCFixup, 4> Fixups;
SmallString<256> Code;
raw_svector_ostream VecOS(Code);
getAssembler().getEmitter().EncodeInstruction(Inst, VecOS, Fixups);
VecOS.flush();
IF->getContents() = Code;
IF->getFixups() = Fixups;
}
void MCPureStreamer::EmitInstToData(const MCInst &Inst) {
MCDataFragment *DF = getOrCreateDataFragment();
SmallVector<MCFixup, 4> Fixups;
SmallString<256> Code;
raw_svector_ostream VecOS(Code);
getAssembler().getEmitter().EncodeInstruction(Inst, VecOS, Fixups);
VecOS.flush();
// Add the fixups and data.
for (unsigned i = 0, e = Fixups.size(); i != e; ++i) {
Fixups[i].setOffset(Fixups[i].getOffset() + DF->getContents().size());
DF->getFixups().push_back(Fixups[i]);
}
DF->getContents().append(Code.begin(), Code.end());
}
void MCPureStreamer::FinishImpl() {
// FIXME: Handle DWARF tables?
this->MCObjectStreamer::FinishImpl();
}
MCStreamer *llvm::createPureStreamer(MCContext &Context, MCAsmBackend &MAB,
raw_ostream &OS, MCCodeEmitter *CE) {
return new MCPureStreamer(Context, MAB, OS, CE);
}
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