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/CodeGen/MachineConstantPool.h"
21 #include "llvm/Target/ELFTargetAsmInfo.h"
22 #include "llvm/Target/TargetMachine.h"
23 #include "llvm/Target/TargetData.h"
27 ELFTargetAsmInfo::ELFTargetAsmInfo(const TargetMachine &TM) {
30 BSSSection_ = getUnnamedSection("\t.bss",
31 SectionFlags::Writeable | SectionFlags::BSS);
32 ReadOnlySection = getNamedSection("\t.rodata", SectionFlags::None);
33 TLSDataSection = getNamedSection("\t.tdata",
34 SectionFlags::Writeable | SectionFlags::TLS);
35 TLSBSSSection = getNamedSection("\t.tbss",
36 SectionFlags::Writeable | SectionFlags::TLS | SectionFlags::BSS);
41 ELFTargetAsmInfo::SelectSectionForGlobal(const GlobalValue *GV) const {
42 SectionKind::Kind Kind = SectionKindForGlobal(GV);
44 if (const Function *F = dyn_cast<Function>(GV)) {
45 switch (F->getLinkage()) {
46 default: assert(0 && "Unknown linkage type!");
47 case Function::InternalLinkage:
48 case Function::DLLExportLinkage:
49 case Function::ExternalLinkage:
51 case Function::WeakLinkage:
52 case Function::LinkOnceLinkage:
53 std::string Name = UniqueSectionForGlobal(GV, Kind);
54 unsigned Flags = SectionFlagsForGlobal(GV, Name.c_str());
55 return getNamedSection(Name.c_str(), Flags);
57 } else if (const GlobalVariable *GVar = dyn_cast<GlobalVariable>(GV)) {
58 if (GVar->mayBeOverridden()) {
59 std::string Name = UniqueSectionForGlobal(GVar, Kind);
60 unsigned Flags = SectionFlagsForGlobal(GVar, Name.c_str());
61 return getNamedSection(Name.c_str(), Flags);
64 case SectionKind::Data:
65 case SectionKind::SmallData:
67 case SectionKind::BSS:
68 case SectionKind::SmallBSS:
69 // ELF targets usually have BSS sections
70 return getBSSSection_();
71 case SectionKind::ROData:
72 case SectionKind::SmallROData:
73 return getReadOnlySection();
74 case SectionKind::RODataMergeStr:
75 return MergeableStringSection(GVar);
76 case SectionKind::RODataMergeConst:
77 return MergeableConstSection(GVar);
78 case SectionKind::ThreadData:
79 // ELF targets usually support TLS stuff
80 return TLSDataSection;
81 case SectionKind::ThreadBSS:
84 assert(0 && "Unsuported section kind for global");
88 assert(0 && "Unsupported global");
92 ELFTargetAsmInfo::SelectSectionForMachineConst(const Type *Ty) const {
93 // FIXME: Support data.rel stuff someday
94 return MergeableConstSection(Ty);
98 ELFTargetAsmInfo::MergeableConstSection(const GlobalVariable *GV) const {
99 Constant *C = GV->getInitializer();
100 return MergeableConstSection(C->getType());
103 inline const Section*
104 ELFTargetAsmInfo::MergeableConstSection(const Type *Ty) const {
105 const TargetData *TD = ETM->getTargetData();
107 // FIXME: string here is temporary, until stuff will fully land in.
108 // We cannot use {Four,Eight,Sixteen}ByteConstantSection here, since it's
109 // currently directly used by asmprinter.
110 unsigned Size = TD->getABITypeSize(Ty);
111 if (Size == 4 || Size == 8 || Size == 16) {
112 std::string Name = ".rodata.cst" + utostr(Size);
114 return getNamedSection(Name.c_str(),
115 SectionFlags::setEntitySize(SectionFlags::Mergeable,
119 return getReadOnlySection();
123 ELFTargetAsmInfo::MergeableStringSection(const GlobalVariable *GV) const {
124 const TargetData *TD = ETM->getTargetData();
125 Constant *C = cast<GlobalVariable>(GV)->getInitializer();
126 const ConstantArray *CVA = cast<ConstantArray>(C);
127 const Type *Ty = CVA->getType()->getElementType();
129 unsigned Size = TD->getABITypeSize(Ty);
131 assert(getCStringSection() && "Should have string section prefix");
133 // We also need alignment here
134 const TargetData *TD = ETM->getTargetData();
135 unsigned Align = TD->getPrefTypeAlignment(Ty);
139 std::string Name = getCStringSection() + utostr(Size) + '.' + utostr(Align);
140 unsigned Flags = SectionFlags::setEntitySize(SectionFlags::Mergeable |
141 SectionFlags::Strings,
143 return getNamedSection(Name.c_str(), Flags);
146 return getReadOnlySection();
149 std::string ELFTargetAsmInfo::printSectionFlags(unsigned flags) const {
150 std::string Flags = ",\"";
152 if (!(flags & SectionFlags::Debug))
154 if (flags & SectionFlags::Code)
156 if (flags & SectionFlags::Writeable)
158 if (flags & SectionFlags::Mergeable)
160 if (flags & SectionFlags::Strings)
162 if (flags & SectionFlags::TLS)
164 if (flags & SectionFlags::Small)
169 // If comment string is '@', e.g. as on ARM - use '%' instead
170 if (strcmp(CommentString, "@") == 0)
175 // FIXME: There can be exceptions here
176 if (flags & SectionFlags::BSS)
181 if (unsigned entitySize = SectionFlags::getEntitySize(flags))
182 Flags += "," + utostr(entitySize);