llvm/lib/MC/MCELFStreamer.h
Benjamin Kramer 36a16015ac Don't drop alignment info on local common symbols.
- On COFF the .lcomm directive has an alignment argument.
- On ELF we fall back to .local + .comm

Based on a patch by NAKAMURA Takumi.

Fixes PR9337, PR9483 and PR10128.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@138976 91177308-0d34-0410-b5e6-96231b3b80d8
2011-09-01 23:04:27 +00:00

142 lines
4.7 KiB
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//===- lib/MC/MCELFStreamer.h - ELF Object Output -------------------------===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file assembles .s files and emits ELF .o object files.
//
//===----------------------------------------------------------------------===//
#ifndef LLVM_MC_MCELFSTREAMER_H
#define LLVM_MC_MCELFSTREAMER_H
#include "llvm/ADT/SmallPtrSet.h"
#include "llvm/ADT/DenseMap.h"
#include "llvm/MC/MCAssembler.h"
#include "llvm/MC/MCContext.h"
#include "llvm/MC/MCObjectStreamer.h"
#include "llvm/MC/MCSectionELF.h"
namespace llvm {
class MCELFStreamer : public MCObjectStreamer {
public:
MCELFStreamer(MCContext &Context, MCAsmBackend &TAB,
raw_ostream &OS, MCCodeEmitter *Emitter)
: MCObjectStreamer(Context, TAB, OS, Emitter) {}
MCELFStreamer(MCContext &Context, MCAsmBackend &TAB,
raw_ostream &OS, MCCodeEmitter *Emitter,
MCAssembler *Assembler)
: MCObjectStreamer(Context, TAB, OS, Emitter, Assembler) {}
~MCELFStreamer() {}
/// @name MCStreamer Interface
/// @{
virtual void InitSections();
virtual void ChangeSection(const MCSection *Section);
virtual void EmitLabel(MCSymbol *Symbol);
virtual void EmitAssemblerFlag(MCAssemblerFlag Flag);
virtual void EmitThumbFunc(MCSymbol *Func);
virtual void EmitAssignment(MCSymbol *Symbol, const MCExpr *Value);
virtual void EmitWeakReference(MCSymbol *Alias, const MCSymbol *Symbol);
virtual void EmitSymbolAttribute(MCSymbol *Symbol, MCSymbolAttr Attribute);
virtual void EmitSymbolDesc(MCSymbol *Symbol, unsigned DescValue) {
assert(0 && "ELF doesn't support this directive");
}
virtual void EmitCommonSymbol(MCSymbol *Symbol, uint64_t Size,
unsigned ByteAlignment);
virtual void BeginCOFFSymbolDef(const MCSymbol *Symbol) {
assert(0 && "ELF doesn't support this directive");
}
virtual void EmitCOFFSymbolStorageClass(int StorageClass) {
assert(0 && "ELF doesn't support this directive");
}
virtual void EmitCOFFSymbolType(int Type) {
assert(0 && "ELF doesn't support this directive");
}
virtual void EndCOFFSymbolDef() {
assert(0 && "ELF doesn't support this directive");
}
virtual void EmitELFSize(MCSymbol *Symbol, const MCExpr *Value) {
MCSymbolData &SD = getAssembler().getOrCreateSymbolData(*Symbol);
SD.setSize(Value);
}
virtual void EmitLocalCommonSymbol(MCSymbol *Symbol, uint64_t Size,
unsigned ByteAlignment);
virtual void EmitZerofill(const MCSection *Section, MCSymbol *Symbol = 0,
unsigned Size = 0, unsigned ByteAlignment = 0) {
assert(0 && "ELF doesn't support this directive");
}
virtual void EmitTBSSSymbol(const MCSection *Section, MCSymbol *Symbol,
uint64_t Size, unsigned ByteAlignment = 0) {
assert(0 && "ELF doesn't support this directive");
}
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 void EmitFileDirective(StringRef Filename);
virtual void Finish();
private:
virtual void EmitInstToFragment(const MCInst &Inst);
virtual void EmitInstToData(const MCInst &Inst);
void fixSymbolsInTLSFixups(const MCExpr *expr);
struct LocalCommon {
MCSymbolData *SD;
uint64_t Size;
unsigned ByteAlignment;
};
std::vector<LocalCommon> LocalCommons;
SmallPtrSet<MCSymbol *, 16> BindingExplicitlySet;
/// @}
void SetSection(StringRef Section, unsigned Type, unsigned Flags,
SectionKind Kind) {
SwitchSection(getContext().getELFSection(Section, Type, Flags, Kind));
}
void SetSectionData() {
SetSection(".data", ELF::SHT_PROGBITS,
ELF::SHF_WRITE |ELF::SHF_ALLOC,
SectionKind::getDataRel());
EmitCodeAlignment(4, 0);
}
void SetSectionText() {
SetSection(".text", ELF::SHT_PROGBITS,
ELF::SHF_EXECINSTR |
ELF::SHF_ALLOC, SectionKind::getText());
EmitCodeAlignment(4, 0);
}
void SetSectionBss() {
SetSection(".bss", ELF::SHT_NOBITS,
ELF::SHF_WRITE |
ELF::SHF_ALLOC, SectionKind::getBSS());
EmitCodeAlignment(4, 0);
}
};
} // end llvm namespace
#endif