llvm/lib/MC/MCSectionELF.cpp
2010-01-22 18:21:23 +00:00

136 lines
4.0 KiB
C++

//===- lib/MC/MCSectionELF.cpp - ELF Code Section Representation ----------===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
#include "llvm/MC/MCSectionELF.h"
#include "llvm/MC/MCAsmInfo.h"
#include "llvm/MC/MCContext.h"
#include "llvm/MC/MCSymbol.h"
#include "llvm/Support/raw_ostream.h"
using namespace llvm;
MCSectionELF *MCSectionELF::
Create(StringRef Section, unsigned Type, unsigned Flags,
SectionKind K, bool isExplicit, MCContext &Ctx) {
return new (Ctx) MCSectionELF(Section, Type, Flags, K, isExplicit);
}
// ShouldOmitSectionDirective - Decides whether a '.section' directive
// should be printed before the section name
bool MCSectionELF::ShouldOmitSectionDirective(StringRef Name,
const MCAsmInfo &MAI) const {
// FIXME: Does .section .bss/.data/.text work everywhere??
if (Name == ".text" || Name == ".data" ||
(Name == ".bss" && !MAI.usesELFSectionDirectiveForBSS()))
return true;
return false;
}
// ShouldPrintSectionType - Only prints the section type if supported
bool MCSectionELF::ShouldPrintSectionType(unsigned Ty) const {
if (IsExplicit && !(Ty == SHT_NOBITS || Ty == SHT_PROGBITS))
return false;
return true;
}
void MCSectionELF::PrintSwitchToSection(const MCAsmInfo &MAI,
raw_ostream &OS) const {
if (ShouldOmitSectionDirective(SectionName, MAI)) {
OS << '\t' << getSectionName() << '\n';
return;
}
OS << "\t.section\t" << getSectionName();
// Handle the weird solaris syntax if desired.
if (MAI.usesSunStyleELFSectionSwitchSyntax() &&
!(Flags & MCSectionELF::SHF_MERGE)) {
if (Flags & MCSectionELF::SHF_ALLOC)
OS << ",#alloc";
if (Flags & MCSectionELF::SHF_EXECINSTR)
OS << ",#execinstr";
if (Flags & MCSectionELF::SHF_WRITE)
OS << ",#write";
if (Flags & MCSectionELF::SHF_TLS)
OS << ",#tls";
} else {
OS << ",\"";
if (Flags & MCSectionELF::SHF_ALLOC)
OS << 'a';
if (Flags & MCSectionELF::SHF_EXECINSTR)
OS << 'x';
if (Flags & MCSectionELF::SHF_WRITE)
OS << 'w';
if (Flags & MCSectionELF::SHF_MERGE)
OS << 'M';
if (Flags & MCSectionELF::SHF_STRINGS)
OS << 'S';
if (Flags & MCSectionELF::SHF_TLS)
OS << 'T';
// If there are target-specific flags, print them.
if (Flags & ~MCSectionELF::TARGET_INDEP_SHF)
PrintTargetSpecificSectionFlags(MAI, OS);
OS << '"';
if (ShouldPrintSectionType(Type)) {
OS << ',';
// If comment string is '@', e.g. as on ARM - use '%' instead
if (MAI.getCommentString()[0] == '@')
OS << '%';
else
OS << '@';
if (Type == MCSectionELF::SHT_INIT_ARRAY)
OS << "init_array";
else if (Type == MCSectionELF::SHT_FINI_ARRAY)
OS << "fini_array";
else if (Type == MCSectionELF::SHT_PREINIT_ARRAY)
OS << "preinit_array";
else if (Type == MCSectionELF::SHT_NOBITS)
OS << "nobits";
else if (Type == MCSectionELF::SHT_PROGBITS)
OS << "progbits";
if (getKind().isMergeable1ByteCString()) {
OS << ",1";
} else if (getKind().isMergeable2ByteCString()) {
OS << ",2";
} else if (getKind().isMergeable4ByteCString() ||
getKind().isMergeableConst4()) {
OS << ",4";
} else if (getKind().isMergeableConst8()) {
OS << ",8";
} else if (getKind().isMergeableConst16()) {
OS << ",16";
}
}
}
OS << '\n';
}
// HasCommonSymbols - True if this section holds common symbols, this is
// indicated on the ELF object file by a symbol with SHN_COMMON section
// header index.
bool MCSectionELF::HasCommonSymbols() const {
if (StringRef(SectionName).startswith(".gnu.linkonce."))
return true;
return false;
}