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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/CodeGen/MachineConstantPool.h"
#include "llvm/Support/ErrorHandling.h"
#include "llvm/Target/ELFTargetAsmInfo.h"
#include "llvm/Target/TargetMachine.h"
#include "llvm/Target/TargetData.h"
using namespace llvm;
ELFTargetAsmInfo::ELFTargetAsmInfo(const TargetMachine &TM)
: TargetAsmInfo(TM) {
BSSSection_ = getUnnamedSection("\t.bss",
SectionFlags::Writable | SectionFlags::BSS);
ReadOnlySection = getNamedSection("\t.rodata", SectionFlags::None);
TLSDataSection = getNamedSection("\t.tdata",
SectionFlags::Writable | SectionFlags::TLS);
TLSBSSSection = getNamedSection("\t.tbss",
SectionFlags::Writable | SectionFlags::TLS | SectionFlags::BSS);
DataRelSection = getNamedSection("\t.data.rel", SectionFlags::Writable);
DataRelLocalSection = getNamedSection("\t.data.rel.local",
SectionFlags::Writable);
DataRelROSection = getNamedSection("\t.data.rel.ro",
SectionFlags::Writable);
DataRelROLocalSection = getNamedSection("\t.data.rel.ro.local",
SectionFlags::Writable);
MergableConst4Section = getNamedSection(".rodata.cst4",
SectionFlags::setEntitySize(SectionFlags::Mergeable, 4));
MergableConst8Section = getNamedSection(".rodata.cst8",
SectionFlags::setEntitySize(SectionFlags::Mergeable, 8));
MergableConst16Section = getNamedSection(".rodata.cst16",
SectionFlags::setEntitySize(SectionFlags::Mergeable, 16));
}
const Section*
ELFTargetAsmInfo::SelectSectionForGlobal(const GlobalValue *GV,
SectionKind Kind) const {
if (Kind.isText()) return TextSection;
if (Kind.isMergableCString())
return MergeableStringSection(cast<GlobalVariable>(GV));
if (Kind.isMergableConst()) {
if (Kind.isMergableConst4())
return MergableConst4Section;
if (Kind.isMergableConst8())
return MergableConst8Section;
if (Kind.isMergableConst16())
return MergableConst16Section;
return ReadOnlySection; // .const
}
if (Kind.isReadOnly()) return getReadOnlySection();
if (Kind.isThreadData()) return TLSDataSection;
if (Kind.isThreadBSS()) return TLSBSSSection;
if (Kind.isBSS()) return getBSSSection_();
if (Kind.isDataNoRel()) return DataSection;
if (Kind.isDataRelLocal()) return DataRelLocalSection;
if (Kind.isDataRel()) return DataRelSection;
if (Kind.isReadOnlyWithRelLocal()) return DataRelROLocalSection;
assert(Kind.isReadOnlyWithRel() && "Unknown section kind");
return DataRelROSection;
}
/// getSectionForMergableConstant - Given a mergable constant with the
/// specified size and relocation information, return a section that it
/// should be placed in.
const Section *
ELFTargetAsmInfo::getSectionForMergableConstant(SectionKind Kind) const {
return SelectSectionForGlobal(0, Kind);
}
/// getFlagsForNamedSection - If this target wants to be able to infer
/// section flags based on the name of the section specified for a global
/// variable, it can implement this.
unsigned ELFTargetAsmInfo::getFlagsForNamedSection(const char *Name) const {
unsigned Flags = 0;
if (Name[0] != '.') return 0;
// Some lame default implementation based on some magic section names.
if (strncmp(Name, ".gnu.linkonce.b.", 16) == 0 ||
strncmp(Name, ".llvm.linkonce.b.", 17) == 0 ||
strncmp(Name, ".gnu.linkonce.sb.", 17) == 0 ||
strncmp(Name, ".llvm.linkonce.sb.", 18) == 0)
Flags |= SectionFlags::BSS;
else if (strcmp(Name, ".tdata") == 0 ||
strncmp(Name, ".tdata.", 7) == 0 ||
strncmp(Name, ".gnu.linkonce.td.", 17) == 0 ||
strncmp(Name, ".llvm.linkonce.td.", 18) == 0)
Flags |= SectionFlags::TLS;
else if (strcmp(Name, ".tbss") == 0 ||
strncmp(Name, ".tbss.", 6) == 0 ||
strncmp(Name, ".gnu.linkonce.tb.", 17) == 0 ||
strncmp(Name, ".llvm.linkonce.tb.", 18) == 0)
Flags |= SectionFlags::BSS | SectionFlags::TLS;
return Flags;
}
const char *
ELFTargetAsmInfo::getSectionPrefixForUniqueGlobal(SectionKind Kind) const{
if (Kind.isText()) return ".gnu.linkonce.t.";
if (Kind.isReadOnly()) return ".gnu.linkonce.r.";
if (Kind.isThreadData()) return ".gnu.linkonce.td.";
if (Kind.isThreadBSS()) return ".gnu.linkonce.tb.";
if (Kind.isBSS()) return ".gnu.linkonce.b.";
if (Kind.isDataNoRel()) return ".gnu.linkonce.d.";
if (Kind.isDataRelLocal()) return ".gnu.linkonce.d.rel.local.";
if (Kind.isDataRel()) return ".gnu.linkonce.d.rel.";
if (Kind.isReadOnlyWithRelLocal()) return ".gnu.linkonce.d.rel.ro.local.";
assert(Kind.isReadOnlyWithRel() && "Unknown section kind");
return ".gnu.linkonce.d.rel.ro.";
}
const Section*
ELFTargetAsmInfo::MergeableStringSection(const GlobalVariable *GV) const {
const TargetData *TD = TM.getTargetData();
Constant *C = cast<GlobalVariable>(GV)->getInitializer();
const Type *Ty = cast<ArrayType>(C->getType())->getElementType();
unsigned Size = TD->getTypeAllocSize(Ty);
if (Size <= 16) {
assert(getCStringSection() && "Should have string section prefix");
// We also need alignment here
unsigned Align = TD->getPrefTypeAlignment(Ty);
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::Writable)
Flags += 'w';
if (flags & SectionFlags::Mergeable)
Flags += 'M';
if (flags & SectionFlags::Strings)
Flags += 'S';
if (flags & SectionFlags::TLS)
Flags += 'T';
Flags += "\",";
// If comment string is '@', e.g. as on ARM - use '%' instead
if (strcmp(CommentString, "@") == 0)
Flags += '%';
else
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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