llvm-mirror/lib/MC/MCSectionELF.cpp
2010-11-17 20:03:54 +00:00

134 lines
3.7 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() {} // anchor.
// 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;
}
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";
OS << '\n';
return;
}
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::XCORE_SHF_CP_SECTION)
OS << 'c';
if (Flags & MCSectionELF::XCORE_SHF_DP_SECTION)
OS << 'd';
OS << '"';
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 (EntrySize) {
assert(Flags & MCSectionELF::SHF_MERGE);
OS << "," << EntrySize;
}
OS << '\n';
}
bool MCSectionELF::UseCodeAlign() const {
return getFlags() & MCSectionELF::SHF_EXECINSTR;
}
bool MCSectionELF::isVirtualSection() const {
return getType() == MCSectionELF::SHT_NOBITS;
}
// 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;
}
unsigned MCSectionELF::DetermineEntrySize(SectionKind Kind) {
if (Kind.isMergeable1ByteCString()) return 1;
if (Kind.isMergeable2ByteCString()) return 2;
if (Kind.isMergeable4ByteCString()) return 4;
if (Kind.isMergeableConst4()) return 4;
if (Kind.isMergeableConst8()) return 8;
if (Kind.isMergeableConst16()) return 16;
return 0;
}