1 //===-- llvm/CodeGen/TargetLoweringObjectFileImpl.cpp - Object File Info --===//
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 implements classes used to handle lowerings specific to common
11 // object file formats.
13 //===----------------------------------------------------------------------===//
15 #include "llvm/CodeGen/TargetLoweringObjectFileImpl.h"
16 #include "llvm/Constants.h"
17 #include "llvm/DerivedTypes.h"
18 #include "llvm/Function.h"
19 #include "llvm/GlobalVariable.h"
20 #include "llvm/Module.h"
21 #include "llvm/CodeGen/MachineModuleInfoImpls.h"
22 #include "llvm/MC/MCContext.h"
23 #include "llvm/MC/MCExpr.h"
24 #include "llvm/MC/MCSectionMachO.h"
25 #include "llvm/MC/MCSectionELF.h"
26 #include "llvm/MC/MCSectionCOFF.h"
27 #include "llvm/MC/MCStreamer.h"
28 #include "llvm/MC/MCSymbol.h"
29 #include "llvm/Target/Mangler.h"
30 #include "llvm/Target/TargetData.h"
31 #include "llvm/Target/TargetMachine.h"
32 #include "llvm/Target/TargetOptions.h"
33 #include "llvm/Support/Dwarf.h"
34 #include "llvm/Support/ELF.h"
35 #include "llvm/Support/ErrorHandling.h"
36 #include "llvm/Support/raw_ostream.h"
37 #include "llvm/ADT/SmallString.h"
38 #include "llvm/ADT/StringExtras.h"
39 #include "llvm/ADT/Triple.h"
41 using namespace dwarf;
43 //===----------------------------------------------------------------------===//
45 //===----------------------------------------------------------------------===//
48 TargetLoweringObjectFileELF::getCFIPersonalitySymbol(const GlobalValue *GV,
50 MachineModuleInfo *MMI) const {
51 unsigned Encoding = getPersonalityEncoding();
52 switch (Encoding & 0x70) {
54 report_fatal_error("We do not support this DWARF encoding yet!");
55 case dwarf::DW_EH_PE_absptr:
56 return Mang->getSymbol(GV);
57 case dwarf::DW_EH_PE_pcrel: {
58 return getContext().GetOrCreateSymbol(StringRef("DW.ref.") +
59 Mang->getSymbol(GV)->getName());
64 void TargetLoweringObjectFileELF::emitPersonalityValue(MCStreamer &Streamer,
65 const TargetMachine &TM,
66 const MCSymbol *Sym) const {
67 SmallString<64> NameData("DW.ref.");
68 NameData += Sym->getName();
69 MCSymbol *Label = getContext().GetOrCreateSymbol(NameData);
70 Streamer.EmitSymbolAttribute(Label, MCSA_Hidden);
71 Streamer.EmitSymbolAttribute(Label, MCSA_Weak);
72 StringRef Prefix = ".data.";
73 NameData.insert(NameData.begin(), Prefix.begin(), Prefix.end());
74 unsigned Flags = ELF::SHF_ALLOC | ELF::SHF_WRITE | ELF::SHF_GROUP;
75 const MCSection *Sec = getContext().getELFSection(NameData,
78 SectionKind::getDataRel(),
80 unsigned Size = TM.getTargetData()->getPointerSize();
81 Streamer.SwitchSection(Sec);
82 Streamer.EmitValueToAlignment(TM.getTargetData()->getPointerABIAlignment());
83 Streamer.EmitSymbolAttribute(Label, MCSA_ELF_TypeObject);
84 const MCExpr *E = MCConstantExpr::Create(Size, getContext());
85 Streamer.EmitELFSize(Label, E);
86 Streamer.EmitLabel(Label);
88 Streamer.EmitSymbolValue(Sym, Size);
92 getELFKindForNamedSection(StringRef Name, SectionKind K) {
93 // N.B.: The defaults used in here are no the same ones used in MC.
94 // We follow gcc, MC follows gas. For example, given ".section .eh_frame",
95 // both gas and MC will produce a section with no flags. Given
96 // section(".eh_frame") gcc will produce
97 // .section .eh_frame,"a",@progbits
98 if (Name.empty() || Name[0] != '.') return K;
100 // Some lame default implementation based on some magic section names.
101 if (Name == ".bss" ||
102 Name.startswith(".bss.") ||
103 Name.startswith(".gnu.linkonce.b.") ||
104 Name.startswith(".llvm.linkonce.b.") ||
106 Name.startswith(".sbss.") ||
107 Name.startswith(".gnu.linkonce.sb.") ||
108 Name.startswith(".llvm.linkonce.sb."))
109 return SectionKind::getBSS();
111 if (Name == ".tdata" ||
112 Name.startswith(".tdata.") ||
113 Name.startswith(".gnu.linkonce.td.") ||
114 Name.startswith(".llvm.linkonce.td."))
115 return SectionKind::getThreadData();
117 if (Name == ".tbss" ||
118 Name.startswith(".tbss.") ||
119 Name.startswith(".gnu.linkonce.tb.") ||
120 Name.startswith(".llvm.linkonce.tb."))
121 return SectionKind::getThreadBSS();
127 static unsigned getELFSectionType(StringRef Name, SectionKind K) {
129 if (Name == ".init_array")
130 return ELF::SHT_INIT_ARRAY;
132 if (Name == ".fini_array")
133 return ELF::SHT_FINI_ARRAY;
135 if (Name == ".preinit_array")
136 return ELF::SHT_PREINIT_ARRAY;
138 if (K.isBSS() || K.isThreadBSS())
139 return ELF::SHT_NOBITS;
141 return ELF::SHT_PROGBITS;
146 getELFSectionFlags(SectionKind K) {
150 Flags |= ELF::SHF_ALLOC;
153 Flags |= ELF::SHF_EXECINSTR;
156 Flags |= ELF::SHF_WRITE;
158 if (K.isThreadLocal())
159 Flags |= ELF::SHF_TLS;
161 // K.isMergeableConst() is left out to honour PR4650
162 if (K.isMergeableCString() || K.isMergeableConst4() ||
163 K.isMergeableConst8() || K.isMergeableConst16())
164 Flags |= ELF::SHF_MERGE;
166 if (K.isMergeableCString())
167 Flags |= ELF::SHF_STRINGS;
173 const MCSection *TargetLoweringObjectFileELF::
174 getExplicitSectionGlobal(const GlobalValue *GV, SectionKind Kind,
175 Mangler *Mang, const TargetMachine &TM) const {
176 StringRef SectionName = GV->getSection();
178 // Infer section flags from the section name if we can.
179 Kind = getELFKindForNamedSection(SectionName, Kind);
181 return getContext().getELFSection(SectionName,
182 getELFSectionType(SectionName, Kind),
183 getELFSectionFlags(Kind), Kind);
186 /// getSectionPrefixForGlobal - Return the section prefix name used by options
187 /// FunctionsSections and DataSections.
188 static const char *getSectionPrefixForGlobal(SectionKind Kind) {
189 if (Kind.isText()) return ".text.";
190 if (Kind.isReadOnly()) return ".rodata.";
191 if (Kind.isBSS()) return ".bss.";
193 if (Kind.isThreadData()) return ".tdata.";
194 if (Kind.isThreadBSS()) return ".tbss.";
196 if (Kind.isDataNoRel()) return ".data.";
197 if (Kind.isDataRelLocal()) return ".data.rel.local.";
198 if (Kind.isDataRel()) return ".data.rel.";
199 if (Kind.isReadOnlyWithRelLocal()) return ".data.rel.ro.local.";
201 assert(Kind.isReadOnlyWithRel() && "Unknown section kind");
202 return ".data.rel.ro.";
206 const MCSection *TargetLoweringObjectFileELF::
207 SelectSectionForGlobal(const GlobalValue *GV, SectionKind Kind,
208 Mangler *Mang, const TargetMachine &TM) const {
209 // If we have -ffunction-section or -fdata-section then we should emit the
210 // global value to a uniqued section specifically for it.
211 bool EmitUniquedSection;
213 EmitUniquedSection = TM.getFunctionSections();
215 EmitUniquedSection = TM.getDataSections();
217 // If this global is linkonce/weak and the target handles this by emitting it
218 // into a 'uniqued' section name, create and return the section now.
219 if ((GV->isWeakForLinker() || EmitUniquedSection) &&
222 Prefix = getSectionPrefixForGlobal(Kind);
224 SmallString<128> Name(Prefix, Prefix+strlen(Prefix));
225 MCSymbol *Sym = Mang->getSymbol(GV);
226 Name.append(Sym->getName().begin(), Sym->getName().end());
227 StringRef Group = "";
228 unsigned Flags = getELFSectionFlags(Kind);
229 if (GV->isWeakForLinker()) {
230 Group = Sym->getName();
231 Flags |= ELF::SHF_GROUP;
234 return getContext().getELFSection(Name.str(),
235 getELFSectionType(Name.str(), Kind),
236 Flags, Kind, 0, Group);
239 if (Kind.isText()) return TextSection;
241 if (Kind.isMergeable1ByteCString() ||
242 Kind.isMergeable2ByteCString() ||
243 Kind.isMergeable4ByteCString()) {
245 // We also need alignment here.
246 // FIXME: this is getting the alignment of the character, not the
247 // alignment of the global!
249 TM.getTargetData()->getPreferredAlignment(cast<GlobalVariable>(GV));
251 const char *SizeSpec = ".rodata.str1.";
252 if (Kind.isMergeable2ByteCString())
253 SizeSpec = ".rodata.str2.";
254 else if (Kind.isMergeable4ByteCString())
255 SizeSpec = ".rodata.str4.";
257 assert(Kind.isMergeable1ByteCString() && "unknown string width");
260 std::string Name = SizeSpec + utostr(Align);
261 return getContext().getELFSection(Name, ELF::SHT_PROGBITS,
268 if (Kind.isMergeableConst()) {
269 if (Kind.isMergeableConst4() && MergeableConst4Section)
270 return MergeableConst4Section;
271 if (Kind.isMergeableConst8() && MergeableConst8Section)
272 return MergeableConst8Section;
273 if (Kind.isMergeableConst16() && MergeableConst16Section)
274 return MergeableConst16Section;
275 return ReadOnlySection; // .const
278 if (Kind.isReadOnly()) return ReadOnlySection;
280 if (Kind.isThreadData()) return TLSDataSection;
281 if (Kind.isThreadBSS()) return TLSBSSSection;
283 // Note: we claim that common symbols are put in BSSSection, but they are
284 // really emitted with the magic .comm directive, which creates a symbol table
285 // entry but not a section.
286 if (Kind.isBSS() || Kind.isCommon()) return BSSSection;
288 if (Kind.isDataNoRel()) return DataSection;
289 if (Kind.isDataRelLocal()) return DataRelLocalSection;
290 if (Kind.isDataRel()) return DataRelSection;
291 if (Kind.isReadOnlyWithRelLocal()) return DataRelROLocalSection;
293 assert(Kind.isReadOnlyWithRel() && "Unknown section kind");
294 return DataRelROSection;
297 /// getSectionForConstant - Given a mergeable constant with the
298 /// specified size and relocation information, return a section that it
299 /// should be placed in.
300 const MCSection *TargetLoweringObjectFileELF::
301 getSectionForConstant(SectionKind Kind) const {
302 if (Kind.isMergeableConst4() && MergeableConst4Section)
303 return MergeableConst4Section;
304 if (Kind.isMergeableConst8() && MergeableConst8Section)
305 return MergeableConst8Section;
306 if (Kind.isMergeableConst16() && MergeableConst16Section)
307 return MergeableConst16Section;
308 if (Kind.isReadOnly())
309 return ReadOnlySection;
311 if (Kind.isReadOnlyWithRelLocal()) return DataRelROLocalSection;
312 assert(Kind.isReadOnlyWithRel() && "Unknown section kind");
313 return DataRelROSection;
316 const MCExpr *TargetLoweringObjectFileELF::
317 getExprForDwarfGlobalReference(const GlobalValue *GV, Mangler *Mang,
318 MachineModuleInfo *MMI,
319 unsigned Encoding, MCStreamer &Streamer) const {
321 if (Encoding & dwarf::DW_EH_PE_indirect) {
322 MachineModuleInfoELF &ELFMMI = MMI->getObjFileInfo<MachineModuleInfoELF>();
324 SmallString<128> Name;
325 Mang->getNameWithPrefix(Name, GV, true);
328 // Add information about the stub reference to ELFMMI so that the stub
329 // gets emitted by the asmprinter.
330 MCSymbol *SSym = getContext().GetOrCreateSymbol(Name.str());
331 MachineModuleInfoImpl::StubValueTy &StubSym = ELFMMI.getGVStubEntry(SSym);
332 if (StubSym.getPointer() == 0) {
333 MCSymbol *Sym = Mang->getSymbol(GV);
334 StubSym = MachineModuleInfoImpl::StubValueTy(Sym, !GV->hasLocalLinkage());
337 return TargetLoweringObjectFile::
338 getExprForDwarfReference(SSym, Encoding & ~dwarf::DW_EH_PE_indirect, Streamer);
341 return TargetLoweringObjectFile::
342 getExprForDwarfGlobalReference(GV, Mang, MMI, Encoding, Streamer);
346 TargetLoweringObjectFileELF::getStaticCtorSection(unsigned Priority) const {
347 // The default scheme is .ctor / .dtor, so we have to invert the priority
349 if (Priority == 65535)
350 return StaticCtorSection;
353 std::string Name = std::string(".init_array.") + utostr(Priority);
354 return getContext().getELFSection(Name, ELF::SHT_INIT_ARRAY,
355 ELF::SHF_ALLOC | ELF::SHF_WRITE,
356 SectionKind::getDataRel());
358 std::string Name = std::string(".ctors.") + utostr(65535 - Priority);
359 return getContext().getELFSection(Name, ELF::SHT_PROGBITS,
360 ELF::SHF_ALLOC |ELF::SHF_WRITE,
361 SectionKind::getDataRel());
366 TargetLoweringObjectFileELF::getStaticDtorSection(unsigned Priority) const {
367 // The default scheme is .ctor / .dtor, so we have to invert the priority
369 if (Priority == 65535)
370 return StaticDtorSection;
373 std::string Name = std::string(".fini_array.") + utostr(Priority);
374 return getContext().getELFSection(Name, ELF::SHT_FINI_ARRAY,
375 ELF::SHF_ALLOC | ELF::SHF_WRITE,
376 SectionKind::getDataRel());
378 std::string Name = std::string(".dtors.") + utostr(65535 - Priority);
379 return getContext().getELFSection(Name, ELF::SHT_PROGBITS,
380 ELF::SHF_ALLOC |ELF::SHF_WRITE,
381 SectionKind::getDataRel());
386 TargetLoweringObjectFileELF::InitializeELF(bool UseInitArray_) {
387 UseInitArray = UseInitArray_;
392 getContext().getELFSection(".init_array", ELF::SHT_INIT_ARRAY,
395 SectionKind::getDataRel());
397 getContext().getELFSection(".fini_array", ELF::SHT_FINI_ARRAY,
400 SectionKind::getDataRel());
403 //===----------------------------------------------------------------------===//
405 //===----------------------------------------------------------------------===//
407 /// emitModuleFlags - Emit the module flags that specify the garbage collection
409 void TargetLoweringObjectFileMachO::
410 emitModuleFlags(MCStreamer &Streamer,
411 ArrayRef<Module::ModuleFlagEntry> ModuleFlags,
412 Mangler *Mang, const TargetMachine &TM) const {
413 unsigned VersionVal = 0;
414 unsigned ImageInfoFlags = 0;
415 StringRef SectionVal;
417 for (ArrayRef<Module::ModuleFlagEntry>::iterator
418 i = ModuleFlags.begin(), e = ModuleFlags.end(); i != e; ++i) {
419 const Module::ModuleFlagEntry &MFE = *i;
421 // Ignore flags with 'Require' behavior.
422 if (MFE.Behavior == Module::Require)
425 StringRef Key = MFE.Key->getString();
426 Value *Val = MFE.Val;
428 if (Key == "Objective-C Image Info Version")
429 VersionVal = cast<ConstantInt>(Val)->getZExtValue();
430 else if (Key == "Objective-C Garbage Collection" ||
431 Key == "Objective-C GC Only" ||
432 Key == "Objective-C Is Simulated")
433 ImageInfoFlags |= cast<ConstantInt>(Val)->getZExtValue();
434 else if (Key == "Objective-C Image Info Section")
435 SectionVal = cast<MDString>(Val)->getString();
438 // The section is mandatory. If we don't have it, then we don't have GC info.
439 if (SectionVal.empty()) return;
441 StringRef Segment, Section;
442 unsigned TAA = 0, StubSize = 0;
444 std::string ErrorCode =
445 MCSectionMachO::ParseSectionSpecifier(SectionVal, Segment, Section,
446 TAA, TAAParsed, StubSize);
447 if (!ErrorCode.empty())
448 // If invalid, report the error with report_fatal_error.
449 report_fatal_error("Invalid section specifier '" + Section + "': " +
453 const MCSectionMachO *S =
454 getContext().getMachOSection(Segment, Section, TAA, StubSize,
455 SectionKind::getDataNoRel());
456 Streamer.SwitchSection(S);
457 Streamer.EmitLabel(getContext().
458 GetOrCreateSymbol(StringRef("L_OBJC_IMAGE_INFO")));
459 Streamer.EmitIntValue(VersionVal, 4);
460 Streamer.EmitIntValue(ImageInfoFlags, 4);
461 Streamer.AddBlankLine();
464 const MCSection *TargetLoweringObjectFileMachO::
465 getExplicitSectionGlobal(const GlobalValue *GV, SectionKind Kind,
466 Mangler *Mang, const TargetMachine &TM) const {
467 // Parse the section specifier and create it if valid.
468 StringRef Segment, Section;
469 unsigned TAA = 0, StubSize = 0;
471 std::string ErrorCode =
472 MCSectionMachO::ParseSectionSpecifier(GV->getSection(), Segment, Section,
473 TAA, TAAParsed, StubSize);
474 if (!ErrorCode.empty()) {
475 // If invalid, report the error with report_fatal_error.
476 report_fatal_error("Global variable '" + GV->getName() +
477 "' has an invalid section specifier '" +
478 GV->getSection() + "': " + ErrorCode + ".");
482 const MCSectionMachO *S =
483 getContext().getMachOSection(Segment, Section, TAA, StubSize, Kind);
485 // If TAA wasn't set by ParseSectionSpecifier() above,
486 // use the value returned by getMachOSection() as a default.
488 TAA = S->getTypeAndAttributes();
490 // Okay, now that we got the section, verify that the TAA & StubSize agree.
491 // If the user declared multiple globals with different section flags, we need
492 // to reject it here.
493 if (S->getTypeAndAttributes() != TAA || S->getStubSize() != StubSize) {
494 // If invalid, report the error with report_fatal_error.
495 report_fatal_error("Global variable '" + GV->getName() +
496 "' section type or attributes does not match previous"
497 " section specifier");
503 const MCSection *TargetLoweringObjectFileMachO::
504 SelectSectionForGlobal(const GlobalValue *GV, SectionKind Kind,
505 Mangler *Mang, const TargetMachine &TM) const {
507 // Handle thread local data.
508 if (Kind.isThreadBSS()) return TLSBSSSection;
509 if (Kind.isThreadData()) return TLSDataSection;
512 return GV->isWeakForLinker() ? TextCoalSection : TextSection;
514 // If this is weak/linkonce, put this in a coalescable section, either in text
515 // or data depending on if it is writable.
516 if (GV->isWeakForLinker()) {
517 if (Kind.isReadOnly())
518 return ConstTextCoalSection;
519 return DataCoalSection;
522 // FIXME: Alignment check should be handled by section classifier.
523 if (Kind.isMergeable1ByteCString() &&
524 TM.getTargetData()->getPreferredAlignment(cast<GlobalVariable>(GV)) < 32)
525 return CStringSection;
527 // Do not put 16-bit arrays in the UString section if they have an
528 // externally visible label, this runs into issues with certain linker
530 if (Kind.isMergeable2ByteCString() && !GV->hasExternalLinkage() &&
531 TM.getTargetData()->getPreferredAlignment(cast<GlobalVariable>(GV)) < 32)
532 return UStringSection;
534 if (Kind.isMergeableConst()) {
535 if (Kind.isMergeableConst4())
536 return FourByteConstantSection;
537 if (Kind.isMergeableConst8())
538 return EightByteConstantSection;
539 if (Kind.isMergeableConst16() && SixteenByteConstantSection)
540 return SixteenByteConstantSection;
543 // Otherwise, if it is readonly, but not something we can specially optimize,
544 // just drop it in .const.
545 if (Kind.isReadOnly())
546 return ReadOnlySection;
548 // If this is marked const, put it into a const section. But if the dynamic
549 // linker needs to write to it, put it in the data segment.
550 if (Kind.isReadOnlyWithRel())
551 return ConstDataSection;
553 // Put zero initialized globals with strong external linkage in the
554 // DATA, __common section with the .zerofill directive.
555 if (Kind.isBSSExtern())
556 return DataCommonSection;
558 // Put zero initialized globals with local linkage in __DATA,__bss directive
559 // with the .zerofill directive (aka .lcomm).
560 if (Kind.isBSSLocal())
561 return DataBSSSection;
563 // Otherwise, just drop the variable in the normal data section.
568 TargetLoweringObjectFileMachO::getSectionForConstant(SectionKind Kind) const {
569 // If this constant requires a relocation, we have to put it in the data
570 // segment, not in the text segment.
571 if (Kind.isDataRel() || Kind.isReadOnlyWithRel())
572 return ConstDataSection;
574 if (Kind.isMergeableConst4())
575 return FourByteConstantSection;
576 if (Kind.isMergeableConst8())
577 return EightByteConstantSection;
578 if (Kind.isMergeableConst16() && SixteenByteConstantSection)
579 return SixteenByteConstantSection;
580 return ReadOnlySection; // .const
583 /// shouldEmitUsedDirectiveFor - This hook allows targets to selectively decide
584 /// not to emit the UsedDirective for some symbols in llvm.used.
585 // FIXME: REMOVE this (rdar://7071300)
586 bool TargetLoweringObjectFileMachO::
587 shouldEmitUsedDirectiveFor(const GlobalValue *GV, Mangler *Mang) const {
588 /// On Darwin, internally linked data beginning with "L" or "l" does not have
589 /// the directive emitted (this occurs in ObjC metadata).
590 if (!GV) return false;
592 // Check whether the mangled name has the "Private" or "LinkerPrivate" prefix.
593 if (GV->hasLocalLinkage() && !isa<Function>(GV)) {
594 // FIXME: ObjC metadata is currently emitted as internal symbols that have
595 // \1L and \0l prefixes on them. Fix them to be Private/LinkerPrivate and
596 // this horrible hack can go away.
597 MCSymbol *Sym = Mang->getSymbol(GV);
598 if (Sym->getName()[0] == 'L' || Sym->getName()[0] == 'l')
605 const MCExpr *TargetLoweringObjectFileMachO::
606 getExprForDwarfGlobalReference(const GlobalValue *GV, Mangler *Mang,
607 MachineModuleInfo *MMI, unsigned Encoding,
608 MCStreamer &Streamer) const {
609 // The mach-o version of this method defaults to returning a stub reference.
611 if (Encoding & DW_EH_PE_indirect) {
612 MachineModuleInfoMachO &MachOMMI =
613 MMI->getObjFileInfo<MachineModuleInfoMachO>();
615 SmallString<128> Name;
616 Mang->getNameWithPrefix(Name, GV, true);
617 Name += "$non_lazy_ptr";
619 // Add information about the stub reference to MachOMMI so that the stub
620 // gets emitted by the asmprinter.
621 MCSymbol *SSym = getContext().GetOrCreateSymbol(Name.str());
622 MachineModuleInfoImpl::StubValueTy &StubSym =
623 GV->hasHiddenVisibility() ? MachOMMI.getHiddenGVStubEntry(SSym) :
624 MachOMMI.getGVStubEntry(SSym);
625 if (StubSym.getPointer() == 0) {
626 MCSymbol *Sym = Mang->getSymbol(GV);
627 StubSym = MachineModuleInfoImpl::StubValueTy(Sym, !GV->hasLocalLinkage());
630 return TargetLoweringObjectFile::
631 getExprForDwarfReference(SSym, Encoding & ~dwarf::DW_EH_PE_indirect, Streamer);
634 return TargetLoweringObjectFile::
635 getExprForDwarfGlobalReference(GV, Mang, MMI, Encoding, Streamer);
638 MCSymbol *TargetLoweringObjectFileMachO::
639 getCFIPersonalitySymbol(const GlobalValue *GV, Mangler *Mang,
640 MachineModuleInfo *MMI) const {
641 // The mach-o version of this method defaults to returning a stub reference.
642 MachineModuleInfoMachO &MachOMMI =
643 MMI->getObjFileInfo<MachineModuleInfoMachO>();
645 SmallString<128> Name;
646 Mang->getNameWithPrefix(Name, GV, true);
647 Name += "$non_lazy_ptr";
649 // Add information about the stub reference to MachOMMI so that the stub
650 // gets emitted by the asmprinter.
651 MCSymbol *SSym = getContext().GetOrCreateSymbol(Name.str());
652 MachineModuleInfoImpl::StubValueTy &StubSym = MachOMMI.getGVStubEntry(SSym);
653 if (StubSym.getPointer() == 0) {
654 MCSymbol *Sym = Mang->getSymbol(GV);
655 StubSym = MachineModuleInfoImpl::StubValueTy(Sym, !GV->hasLocalLinkage());
661 //===----------------------------------------------------------------------===//
663 //===----------------------------------------------------------------------===//
666 getCOFFSectionFlags(SectionKind K) {
671 COFF::IMAGE_SCN_MEM_DISCARDABLE;
674 COFF::IMAGE_SCN_MEM_EXECUTE |
675 COFF::IMAGE_SCN_MEM_READ |
676 COFF::IMAGE_SCN_CNT_CODE;
679 COFF::IMAGE_SCN_CNT_UNINITIALIZED_DATA |
680 COFF::IMAGE_SCN_MEM_READ |
681 COFF::IMAGE_SCN_MEM_WRITE;
682 else if (K.isThreadLocal())
684 COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
685 COFF::IMAGE_SCN_MEM_READ |
686 COFF::IMAGE_SCN_MEM_WRITE;
687 else if (K.isReadOnly())
689 COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
690 COFF::IMAGE_SCN_MEM_READ;
691 else if (K.isWriteable())
693 COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
694 COFF::IMAGE_SCN_MEM_READ |
695 COFF::IMAGE_SCN_MEM_WRITE;
700 const MCSection *TargetLoweringObjectFileCOFF::
701 getExplicitSectionGlobal(const GlobalValue *GV, SectionKind Kind,
702 Mangler *Mang, const TargetMachine &TM) const {
703 return getContext().getCOFFSection(GV->getSection(),
704 getCOFFSectionFlags(Kind),
708 static const char *getCOFFSectionPrefixForUniqueGlobal(SectionKind Kind) {
713 if (Kind.isThreadLocal())
715 if (Kind.isWriteable())
721 const MCSection *TargetLoweringObjectFileCOFF::
722 SelectSectionForGlobal(const GlobalValue *GV, SectionKind Kind,
723 Mangler *Mang, const TargetMachine &TM) const {
725 // If this global is linkonce/weak and the target handles this by emitting it
726 // into a 'uniqued' section name, create and return the section now.
727 if (GV->isWeakForLinker()) {
728 const char *Prefix = getCOFFSectionPrefixForUniqueGlobal(Kind);
729 SmallString<128> Name(Prefix, Prefix+strlen(Prefix));
730 MCSymbol *Sym = Mang->getSymbol(GV);
731 Name.append(Sym->getName().begin() + 1, Sym->getName().end());
733 unsigned Characteristics = getCOFFSectionFlags(Kind);
735 Characteristics |= COFF::IMAGE_SCN_LNK_COMDAT;
737 return getContext().getCOFFSection(Name.str(), Characteristics,
738 COFF::IMAGE_COMDAT_SELECT_ANY, Kind);
742 return getTextSection();
744 if (Kind.isThreadLocal())
745 return getTLSDataSection();
747 return getDataSection();