llvm-6502/lib/MC/MCSectionELF.cpp
Jan Wen Voung 083cf1574f Add hook in MCSection to decide when to use "optimized nops", for each
section kind. Previously, optimized nops were only used for MachO.
Also added tests for ELF and COFF.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@115523 91177308-0d34-0410-b5e6-96231b3b80d8
2010-10-04 17:32:41 +00:00

139 lines
3.9 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;
}
// 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";
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 << '"';
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 (EntrySize) {
OS << "," << EntrySize;
}
}
OS << '\n';
}
bool MCSectionELF::UseCodeAlign() const {
return getFlags() & MCSectionELF::SHF_EXECINSTR;
}
// 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;
}