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_ = getOrCreateSection("\t.cstring", true,
32 SectionKind::MergeableCString);
33 FourByteConstantSection = getOrCreateSection("\t.literal4\n", true,
34 SectionKind::MergeableConst4);
35 EightByteConstantSection = getOrCreateSection("\t.literal8\n", true,
36 SectionKind::MergeableConst8);
37 SixteenByteConstantSection =
38 getOrCreateSection("\t.literal16\n", true, SectionKind::MergeableConst16);
40 ReadOnlySection = getOrCreateSection("\t.const", true, SectionKind::ReadOnly);
43 getOrCreateSection("\t__TEXT,__textcoal_nt,coalesced,pure_instructions",
44 false, SectionKind::Text);
45 ConstTextCoalSection = getOrCreateSection("\t__TEXT,__const_coal,coalesced",
46 false, SectionKind::Text);
47 ConstDataCoalSection = getOrCreateSection("\t__DATA,__const_coal,coalesced",
48 false, SectionKind::Text);
49 ConstDataSection = getOrCreateSection("\t.const_data", true,
50 SectionKind::ReadOnlyWithRel);
51 DataCoalSection = getOrCreateSection("\t__DATA,__datacoal_nt,coalesced",
52 false, SectionKind::DataRel);
55 // Common settings for all Darwin targets.
58 PrivateGlobalPrefix = "L";
59 LinkerPrivateGlobalPrefix = "l"; // Marker for some ObjC metadata
61 NeedsIndirectEncoding = true;
62 AllowQuotesInName = true;
63 HasSingleParameterDotFile = false;
65 // In non-PIC modes, emit a special label before jump tables so that the
66 // linker can perform more accurate dead code stripping. We do not check the
67 // relocation model here since it can be overridden later.
68 JumpTableSpecialLabelPrefix = "l";
71 WeakDefDirective = "\t.weak_definition ";
72 WeakRefDirective = "\t.weak_reference ";
73 HiddenDirective = "\t.private_extern ";
76 CStringSection = "\t.cstring";
77 JumpTableDataSection = "\t.const";
80 if (TM.getRelocationModel() == Reloc::Static) {
81 StaticCtorsSection = ".constructor";
82 StaticDtorsSection = ".destructor";
84 StaticCtorsSection = ".mod_init_func";
85 StaticDtorsSection = ".mod_term_func";
88 // _foo.eh symbols are currently always exported so that the linker knows
89 // about them. This may not strictly be necessary on 10.6 and later, but it
90 // doesn't hurt anything.
91 Is_EHSymbolPrivate = false;
93 DwarfAbbrevSection = ".section __DWARF,__debug_abbrev,regular,debug";
94 DwarfInfoSection = ".section __DWARF,__debug_info,regular,debug";
95 DwarfLineSection = ".section __DWARF,__debug_line,regular,debug";
96 DwarfFrameSection = ".section __DWARF,__debug_frame,regular,debug";
97 DwarfPubNamesSection = ".section __DWARF,__debug_pubnames,regular,debug";
98 DwarfPubTypesSection = ".section __DWARF,__debug_pubtypes,regular,debug";
99 DwarfStrSection = ".section __DWARF,__debug_str,regular,debug";
100 DwarfLocSection = ".section __DWARF,__debug_loc,regular,debug";
101 DwarfARangesSection = ".section __DWARF,__debug_aranges,regular,debug";
102 DwarfRangesSection = ".section __DWARF,__debug_ranges,regular,debug";
103 DwarfMacroInfoSection = ".section __DWARF,__debug_macinfo,regular,debug";
106 /// emitUsedDirectiveFor - On Darwin, internally linked data beginning with
107 /// the PrivateGlobalPrefix or the LinkerPrivateGlobalPrefix does not have the
108 /// directive emitted (this occurs in ObjC metadata).
109 bool DarwinTargetAsmInfo::emitUsedDirectiveFor(const GlobalValue* GV,
110 Mangler *Mang) const {
111 if (!GV) return false;
113 // Check whether the mangled name has the "Private" or "LinkerPrivate" prefix.
114 if (GV->hasLocalLinkage() && !isa<Function>(GV)) {
115 // FIXME: ObjC metadata is currently emitted as internal symbols that have
116 // \1L and \0l prefixes on them. Fix them to be Private/LinkerPrivate and
117 // this horrible hack can go away.
118 const std::string &Name = Mang->getMangledName(GV);
119 if (Name[0] == 'L' || Name[0] == 'l')
127 DarwinTargetAsmInfo::SelectSectionForGlobal(const GlobalValue *GV,
128 SectionKind Kind) const {
129 assert(!Kind.isThreadLocal() && "Darwin doesn't support TLS");
132 return Kind.isWeak() ? TextCoalSection : TextSection;
134 // If this is weak/linkonce, put this in a coalescable section, either in text
135 // or data depending on if it is writable.
137 if (Kind.isReadOnly())
138 return ConstTextCoalSection;
139 return DataCoalSection;
142 // FIXME: Alignment check should be handled by section classifier.
143 if (Kind.isMergeableCString())
144 return MergeableStringSection(cast<GlobalVariable>(GV));
146 if (Kind.isMergeableConst()) {
147 if (Kind.isMergeableConst4())
148 return FourByteConstantSection;
149 if (Kind.isMergeableConst8())
150 return EightByteConstantSection;
151 if (Kind.isMergeableConst16())
152 return SixteenByteConstantSection;
153 return ReadOnlySection; // .const
156 // FIXME: ROData -> const in -static mode that is relocatable but they happen
157 // by the static linker. Why not mergeable?
158 if (Kind.isReadOnly())
159 return getReadOnlySection();
161 // If this is marked const, put it into a const section. But if the dynamic
162 // linker needs to write to it, put it in the data segment.
163 if (Kind.isReadOnlyWithRel())
164 return ConstDataSection;
166 // Otherwise, just drop the variable in the normal data section.
171 DarwinTargetAsmInfo::MergeableStringSection(const GlobalVariable *GV) const {
172 const TargetData *TD = TM.getTargetData();
173 Constant *C = cast<GlobalVariable>(GV)->getInitializer();
174 const Type *Ty = cast<ArrayType>(C->getType())->getElementType();
176 unsigned Size = TD->getTypeAllocSize(Ty);
178 unsigned Align = TD->getPreferredAlignment(GV);
180 return getCStringSection_();
183 return getReadOnlySection();
187 DarwinTargetAsmInfo::getSectionForMergeableConstant(SectionKind Kind) const {
188 // If this constant requires a relocation, we have to put it in the data
189 // segment, not in the text segment.
190 if (Kind.isDataRel())
191 return ConstDataSection;
193 if (Kind.isMergeableConst4())
194 return FourByteConstantSection;
195 if (Kind.isMergeableConst8())
196 return EightByteConstantSection;
197 if (Kind.isMergeableConst16())
198 return SixteenByteConstantSection;
199 return ReadOnlySection; // .const