1 //===-- ELFTargetAsmInfo.cpp - ELF asm properties ---------------*- C++ -*-===//
3 // The LLVM Compiler Infrastructure
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
10 // This file defines target asm properties related what form asm statements
11 // should take in general on ELF-based targets
13 //===----------------------------------------------------------------------===//
15 #include "llvm/Constants.h"
16 #include "llvm/DerivedTypes.h"
17 #include "llvm/Function.h"
18 #include "llvm/GlobalVariable.h"
19 #include "llvm/ADT/StringExtras.h"
20 #include "llvm/Target/ELFTargetAsmInfo.h"
21 #include "llvm/Target/TargetMachine.h"
22 #include "llvm/Target/TargetData.h"
26 ELFTargetAsmInfo::ELFTargetAsmInfo(const TargetMachine &TM) {
29 TextSection_ = getUnnamedSection("\t.text", SectionFlags::Code);
30 DataSection_ = getUnnamedSection("\t.data", SectionFlags::Writeable);
31 BSSSection_ = getUnnamedSection("\t.bss",
32 SectionFlags::Writeable | SectionFlags::BSS);
33 ReadOnlySection_ = getNamedSection("\t.rodata", SectionFlags::None);
34 TLSDataSection_ = getNamedSection("\t.tdata",
35 SectionFlags::Writeable | SectionFlags::TLS);
36 TLSBSSSection_ = getNamedSection("\t.tbss",
37 SectionFlags::Writeable | SectionFlags::TLS | SectionFlags::BSS);
42 ELFTargetAsmInfo::SelectSectionForGlobal(const GlobalValue *GV) const {
43 SectionKind::Kind Kind = SectionKindForGlobal(GV);
45 if (const Function *F = dyn_cast<Function>(GV)) {
46 switch (F->getLinkage()) {
47 default: assert(0 && "Unknown linkage type!");
48 case Function::InternalLinkage:
49 case Function::DLLExportLinkage:
50 case Function::ExternalLinkage:
51 return getTextSection_();
52 case Function::WeakLinkage:
53 case Function::LinkOnceLinkage:
54 std::string Name = UniqueSectionForGlobal(GV, Kind);
55 unsigned Flags = SectionFlagsForGlobal(GV, Name.c_str());
56 return getNamedSection(Name.c_str(), Flags);
58 } else if (const GlobalVariable *GVar = dyn_cast<GlobalVariable>(GV)) {
59 if (GVar->isWeakForLinker()) {
60 std::string Name = UniqueSectionForGlobal(GVar, Kind);
61 unsigned Flags = SectionFlagsForGlobal(GVar, Name.c_str());
62 return getNamedSection(Name.c_str(), Flags);
65 case SectionKind::Data:
66 case SectionKind::SmallData:
67 return getDataSection_();
68 case SectionKind::BSS:
69 case SectionKind::SmallBSS:
70 // ELF targets usually have BSS sections
71 return getBSSSection_();
72 case SectionKind::ROData:
73 case SectionKind::SmallROData:
74 return getReadOnlySection_();
75 case SectionKind::RODataMergeStr:
76 return MergeableStringSection(GVar);
77 case SectionKind::RODataMergeConst:
78 return MergeableConstSection(GVar);
79 case SectionKind::ThreadData:
80 // ELF targets usually support TLS stuff
81 return getTLSDataSection_();
82 case SectionKind::ThreadBSS:
83 return getTLSBSSSection_();
85 assert(0 && "Unsuported section kind for global");
89 assert(0 && "Unsupported global");
93 ELFTargetAsmInfo::MergeableConstSection(const GlobalVariable *GV) const {
94 const TargetData *TD = ETM->getTargetData();
95 Constant *C = cast<GlobalVariable>(GV)->getInitializer();
96 const Type *Type = C->getType();
98 // FIXME: string here is temporary, until stuff will fully land in.
99 // We cannot use {Four,Eight,Sixteen}ByteConstantSection here, since it's
100 // currently directly used by asmprinter.
101 unsigned Size = TD->getABITypeSize(Type);
102 if (Size == 4 || Size == 8 || Size == 16) {
103 std::string Name = ".rodata.cst" + utostr(Size);
105 return getNamedSection(Name.c_str(),
106 SectionFlags::setEntitySize(SectionFlags::Mergeable,
110 return getReadOnlySection_();
114 ELFTargetAsmInfo::MergeableStringSection(const GlobalVariable *GV) const {
115 const TargetData *TD = ETM->getTargetData();
116 Constant *C = cast<GlobalVariable>(GV)->getInitializer();
117 const ConstantArray *CVA = cast<ConstantArray>(C);
118 const Type *Ty = CVA->getType()->getElementType();
120 unsigned Size = TD->getABITypeSize(Ty);
122 // We also need alignment here
123 const TargetData *TD = ETM->getTargetData();
124 unsigned Align = TD->getPrefTypeAlignment(Ty);
128 std::string Name = getCStringSection() + utostr(Size) + '.' + utostr(Align);
129 unsigned Flags = SectionFlags::setEntitySize(SectionFlags::Mergeable |
130 SectionFlags::Strings,
132 return getNamedSection(Name.c_str(), Flags);
135 return getReadOnlySection_();
138 std::string ELFTargetAsmInfo::PrintSectionFlags(unsigned flags) const {
139 std::string Flags = ",\"";
141 if (!(flags & SectionFlags::Debug))
143 if (flags & SectionFlags::Code)
145 if (flags & SectionFlags::Writeable)
147 if (flags & SectionFlags::Mergeable)
149 if (flags & SectionFlags::Strings)
151 if (flags & SectionFlags::TLS)
153 if (flags & SectionFlags::Small)
158 // FIXME: There can be exceptions here
159 if (flags & SectionFlags::BSS)
162 Flags += ",@progbits";
164 if (unsigned entitySize = SectionFlags::getEntitySize(flags))
165 Flags += "," + utostr(entitySize);