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//===-- ELFTargetAsmInfo.cpp - ELF asm properties ---------------*- C++ -*-===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file defines target asm properties related what form asm statements
// should take in general on ELF-based targets
//
//===----------------------------------------------------------------------===//
#include "llvm/Constants.h"
#include "llvm/DerivedTypes.h"
#include "llvm/Function.h"
#include "llvm/GlobalVariable.h"
#include "llvm/ADT/StringExtras.h"
#include "llvm/Target/ELFTargetAsmInfo.h"
#include "llvm/Target/TargetMachine.h"
#include "llvm/Target/TargetData.h"
using namespace llvm;
ELFTargetAsmInfo::ELFTargetAsmInfo(const TargetMachine &TM) {
ETM = &TM;
TextSection_ = getUnnamedSection("\t.text", SectionFlags::Code);
DataSection_ = getUnnamedSection("\t.data", SectionFlags::Writeable);
BSSSection_ = getUnnamedSection("\t.bss",
SectionFlags::Writeable | SectionFlags::BSS);
ReadOnlySection_ = getNamedSection("\t.rodata", SectionFlags::None);
TLSDataSection_ = getNamedSection("\t.tdata",
SectionFlags::Writeable | SectionFlags::TLS);
TLSBSSSection_ = getNamedSection("\t.tbss",
SectionFlags::Writeable | SectionFlags::TLS | SectionFlags::BSS);
}
const Section*
ELFTargetAsmInfo::SelectSectionForGlobal(const GlobalValue *GV) const {
SectionKind::Kind Kind = SectionKindForGlobal(GV);
if (const Function *F = dyn_cast<Function>(GV)) {
switch (F->getLinkage()) {
default: assert(0 && "Unknown linkage type!");
case Function::InternalLinkage:
case Function::DLLExportLinkage:
case Function::ExternalLinkage:
return getTextSection_();
case Function::WeakLinkage:
case Function::LinkOnceLinkage:
std::string Name = UniqueSectionForGlobal(GV, Kind);
unsigned Flags = SectionFlagsForGlobal(GV, Name.c_str());
return getNamedSection(Name.c_str(), Flags);
}
} else if (const GlobalVariable *GVar = dyn_cast<GlobalVariable>(GV)) {
if (GVar->isWeakForLinker()) {
std::string Name = UniqueSectionForGlobal(GVar, Kind);
unsigned Flags = SectionFlagsForGlobal(GVar, Name.c_str());
return getNamedSection(Name.c_str(), Flags);
} else {
switch (Kind) {
case SectionKind::Data:
return getDataSection_();
case SectionKind::BSS:
// ELF targets usually have BSS sections
return getBSSSection_();
case SectionKind::ROData:
return getReadOnlySection_();
case SectionKind::RODataMergeStr:
return MergeableStringSection(GVar);
case SectionKind::RODataMergeConst:
return MergeableConstSection(GVar);
case SectionKind::ThreadData:
// ELF targets usually support TLS stuff
return getTLSDataSection_();
case SectionKind::ThreadBSS:
return getTLSBSSSection_();
default:
assert(0 && "Unsuported section kind for global");
}
}
} else
assert(0 && "Unsupported global");
}
const Section*
ELFTargetAsmInfo::MergeableConstSection(const GlobalVariable *GV) const {
const TargetData *TD = ETM->getTargetData();
Constant *C = cast<GlobalVariable>(GV)->getInitializer();
const Type *Type = C->getType();
// FIXME: string here is temporary, until stuff will fully land in.
// We cannot use {Four,Eight,Sixteen}ByteConstantSection here, since it's
// currently directly used by asmprinter.
unsigned Size = TD->getABITypeSize(Type);
if (Size == 4 || Size == 8 || Size == 16) {
std::string Name = ".rodata.cst" + utostr(Size);
return getNamedSection(Name.c_str(),
SectionFlags::setEntitySize(SectionFlags::Mergeable,
Size));
}
return getReadOnlySection_();
}
const Section*
ELFTargetAsmInfo::MergeableStringSection(const GlobalVariable *GV) const {
const TargetData *TD = ETM->getTargetData();
Constant *C = cast<GlobalVariable>(GV)->getInitializer();
const ConstantArray *CVA = cast<ConstantArray>(C);
const Type *Type = CVA->getType()->getElementType();
unsigned Size = TD->getABITypeSize(Type);
if (Size <= 16) {
// We also need alignment here
const TargetData *TD = ETM->getTargetData();
unsigned Align = TD->getPrefTypeAlignment(Type);
if (Align < Size)
Align = Size;
std::string Name = getCStringSection() + utostr(Size) + '.' + utostr(Align);
unsigned Flags = SectionFlags::setEntitySize(SectionFlags::Mergeable |
SectionFlags::Strings,
Size);
return getNamedSection(Name.c_str(), Flags);
}
return getReadOnlySection_();
}
std::string ELFTargetAsmInfo::PrintSectionFlags(unsigned flags) const {
std::string Flags = ",\"";
if (!(flags & SectionFlags::Debug))
Flags += 'a';
if (flags & SectionFlags::Code)
Flags += 'x';
if (flags & SectionFlags::Writeable)
Flags += 'w';
if (flags & SectionFlags::Mergeable)
Flags += 'M';
if (flags & SectionFlags::Strings)
Flags += 'S';
if (flags & SectionFlags::TLS)
Flags += 'T';
Flags += "\"";
// FIXME: There can be exceptions here
if (flags & SectionFlags::BSS)
Flags += ",@nobits";
else
Flags += ",@progbits";
if (unsigned entitySize = SectionFlags::getEntitySize(flags))
Flags += "," + utostr(entitySize);
return Flags;
}
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