1 //===-- DarwinTargetAsmInfo.cpp - Darwin 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 Darwin-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/Support/ErrorHandling.h"
21 #include "llvm/Support/Mangler.h"
22 #include "llvm/Target/DarwinTargetAsmInfo.h"
23 #include "llvm/Target/TargetMachine.h"
24 #include "llvm/Target/TargetData.h"
28 DarwinTargetAsmInfo::DarwinTargetAsmInfo(const TargetMachine &TM)
31 CStringSection_ = getUnnamedSection("\t.cstring",
32 SectionFlags::Mergeable |SectionFlags::Strings);
33 FourByteConstantSection = getUnnamedSection("\t.literal4\n",
34 SectionFlags::Mergeable);
35 EightByteConstantSection = getUnnamedSection("\t.literal8\n",
36 SectionFlags::Mergeable);
38 // Note: 16-byte constant section is subtarget specific and should be provided
40 SixteenByteConstantSection = 0;
42 ReadOnlySection = getUnnamedSection("\t.const", SectionFlags::None);
45 getNamedSection("\t__TEXT,__textcoal_nt,coalesced,pure_instructions",
47 ConstTextCoalSection = getNamedSection("\t__TEXT,__const_coal,coalesced",
49 ConstDataCoalSection = getNamedSection("\t__DATA,__const_coal,coalesced",
51 ConstDataSection = getUnnamedSection("\t.const_data", SectionFlags::None);
52 DataCoalSection = getNamedSection("\t__DATA,__datacoal_nt,coalesced",
53 SectionFlags::Writable);
56 // Common settings for all Darwin targets.
59 PrivateGlobalPrefix = "L";
60 LinkerPrivateGlobalPrefix = "l"; // Marker for some ObjC metadata
62 NeedsIndirectEncoding = true;
63 AllowQuotesInName = true;
64 HasSingleParameterDotFile = false;
66 // In non-PIC modes, emit a special label before jump tables so that the
67 // linker can perform more accurate dead code stripping. We do not check the
68 // relocation model here since it can be overridden later.
69 JumpTableSpecialLabelPrefix = "l";
72 WeakDefDirective = "\t.weak_definition ";
73 WeakRefDirective = "\t.weak_reference ";
74 HiddenDirective = "\t.private_extern ";
77 CStringSection = "\t.cstring";
78 JumpTableDataSection = "\t.const";
81 if (TM.getRelocationModel() == Reloc::Static) {
82 StaticCtorsSection = ".constructor";
83 StaticDtorsSection = ".destructor";
85 StaticCtorsSection = ".mod_init_func";
86 StaticDtorsSection = ".mod_term_func";
89 // _foo.eh symbols are currently always exported so that the linker knows
90 // about them. This may not strictly be necessary on 10.6 and later, but it
91 // doesn't hurt anything.
92 Is_EHSymbolPrivate = false;
94 DwarfAbbrevSection = ".section __DWARF,__debug_abbrev,regular,debug";
95 DwarfInfoSection = ".section __DWARF,__debug_info,regular,debug";
96 DwarfLineSection = ".section __DWARF,__debug_line,regular,debug";
97 DwarfFrameSection = ".section __DWARF,__debug_frame,regular,debug";
98 DwarfPubNamesSection = ".section __DWARF,__debug_pubnames,regular,debug";
99 DwarfPubTypesSection = ".section __DWARF,__debug_pubtypes,regular,debug";
100 DwarfStrSection = ".section __DWARF,__debug_str,regular,debug";
101 DwarfLocSection = ".section __DWARF,__debug_loc,regular,debug";
102 DwarfARangesSection = ".section __DWARF,__debug_aranges,regular,debug";
103 DwarfRangesSection = ".section __DWARF,__debug_ranges,regular,debug";
104 DwarfMacroInfoSection = ".section __DWARF,__debug_macinfo,regular,debug";
107 /// emitUsedDirectiveFor - On Darwin, internally linked data beginning with
108 /// the PrivateGlobalPrefix or the LinkerPrivateGlobalPrefix does not have the
109 /// directive emitted (this occurs in ObjC metadata).
110 bool DarwinTargetAsmInfo::emitUsedDirectiveFor(const GlobalValue* GV,
111 Mangler *Mang) const {
112 if (!GV) return false;
114 // Check whether the mangled name has the "Private" or "LinkerPrivate" prefix.
115 if (GV->hasLocalLinkage() && !isa<Function>(GV)) {
116 // FIXME: ObjC metadata is currently emitted as internal symbols that have
117 // \1L and \0l prefixes on them. Fix them to be Private/LinkerPrivate and
118 // this horrible hack can go away.
119 const std::string &Name = Mang->getMangledName(GV);
120 if (Name[0] == 'L' || Name[0] == 'l')
128 DarwinTargetAsmInfo::SelectSectionForGlobal(const GlobalValue *GV,
129 SectionKind Kind) const {
130 assert(!Kind.isThreadLocal() && "Darwin doesn't support TLS");
132 // FIXME: Use sectionflags:linkonce instead of isWeakForLinker() here.
133 bool isWeak = GV->isWeakForLinker();
136 return isWeak ? TextCoalSection : TextSection;
138 // If this is weak/linkonce, put this in a coalescable section, either in text
139 // or data depending on if it is writable.
141 if (Kind.isReadOnly())
142 return ConstTextCoalSection;
143 return DataCoalSection;
146 // FIXME: Alignment check should be handled by section classifier.
147 if (Kind.isMergableCString())
148 return MergeableStringSection(cast<GlobalVariable>(GV));
150 if (Kind.isMergableConst()) {
151 if (Kind.isMergableConst4())
152 return FourByteConstantSection;
153 if (Kind.isMergableConst8())
154 return EightByteConstantSection;
155 if (Kind.isMergableConst16() && SixteenByteConstantSection)
156 return SixteenByteConstantSection;
157 return ReadOnlySection; // .const
160 // FIXME: ROData -> const in -static mode that is relocatable but they happen
161 // by the static linker. Why not mergable?
162 if (Kind.isReadOnly())
163 return getReadOnlySection();
165 // If this is marked const, put it into a const section. But if the dynamic
166 // linker needs to write to it, put it in the data segment.
167 if (Kind.isReadOnlyWithRel())
168 return ConstDataSection;
170 // Otherwise, just drop the variable in the normal data section.
175 DarwinTargetAsmInfo::MergeableStringSection(const GlobalVariable *GV) const {
176 const TargetData *TD = TM.getTargetData();
177 Constant *C = cast<GlobalVariable>(GV)->getInitializer();
178 const Type *Ty = cast<ArrayType>(C->getType())->getElementType();
180 unsigned Size = TD->getTypeAllocSize(Ty);
182 unsigned Align = TD->getPreferredAlignment(GV);
184 return getCStringSection_();
187 return getReadOnlySection();
191 DarwinTargetAsmInfo::getSectionForMergableConstant(SectionKind Kind) const {
192 // If this constant requires a relocation, we have to put it in the data
193 // segment, not in the text segment.
194 if (Kind.isDataRel())
195 return ConstDataSection;
197 if (Kind.isMergableConst4())
198 return FourByteConstantSection;
199 if (Kind.isMergableConst8())
200 return EightByteConstantSection;
201 if (Kind.isMergableConst16() && SixteenByteConstantSection)
202 return SixteenByteConstantSection;
203 return ReadOnlySection; // .const