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/ADT/SmallString.h"
17 #include "llvm/ADT/StringExtras.h"
18 #include "llvm/ADT/Triple.h"
19 #include "llvm/CodeGen/MachineModuleInfoImpls.h"
20 #include "llvm/IR/Constants.h"
21 #include "llvm/IR/DataLayout.h"
22 #include "llvm/IR/DerivedTypes.h"
23 #include "llvm/IR/Function.h"
24 #include "llvm/IR/GlobalVariable.h"
25 #include "llvm/IR/Mangler.h"
26 #include "llvm/IR/Module.h"
27 #include "llvm/MC/MCContext.h"
28 #include "llvm/MC/MCExpr.h"
29 #include "llvm/MC/MCSectionCOFF.h"
30 #include "llvm/MC/MCSectionELF.h"
31 #include "llvm/MC/MCSectionMachO.h"
32 #include "llvm/MC/MCStreamer.h"
33 #include "llvm/MC/MCSymbol.h"
34 #include "llvm/Support/Dwarf.h"
35 #include "llvm/Support/ELF.h"
36 #include "llvm/Support/ErrorHandling.h"
37 #include "llvm/Support/raw_ostream.h"
38 #include "llvm/Target/TargetLowering.h"
39 #include "llvm/Target/TargetMachine.h"
40 #include "llvm/Target/TargetSubtargetInfo.h"
42 using namespace dwarf;
44 //===----------------------------------------------------------------------===//
46 //===----------------------------------------------------------------------===//
48 MCSymbol *TargetLoweringObjectFileELF::getCFIPersonalitySymbol(
49 const GlobalValue *GV, Mangler &Mang, const TargetMachine &TM,
50 MachineModuleInfo *MMI) const {
51 unsigned Encoding = getPersonalityEncoding();
52 if ((Encoding & 0x80) == dwarf::DW_EH_PE_indirect)
53 return getContext().GetOrCreateSymbol(StringRef("DW.ref.") +
54 TM.getSymbol(GV, Mang)->getName());
55 if ((Encoding & 0x70) == dwarf::DW_EH_PE_absptr)
56 return TM.getSymbol(GV, Mang);
57 report_fatal_error("We do not support this DWARF encoding yet!");
60 void TargetLoweringObjectFileELF::emitPersonalityValue(MCStreamer &Streamer,
61 const TargetMachine &TM,
62 const MCSymbol *Sym) const {
63 SmallString<64> NameData("DW.ref.");
64 NameData += Sym->getName();
65 MCSymbol *Label = getContext().GetOrCreateSymbol(NameData);
66 Streamer.EmitSymbolAttribute(Label, MCSA_Hidden);
67 Streamer.EmitSymbolAttribute(Label, MCSA_Weak);
68 StringRef Prefix = ".data.";
69 NameData.insert(NameData.begin(), Prefix.begin(), Prefix.end());
70 unsigned Flags = ELF::SHF_ALLOC | ELF::SHF_WRITE | ELF::SHF_GROUP;
71 const MCSection *Sec = getContext().getELFSection(NameData,
74 SectionKind::getDataRel(),
76 unsigned Size = TM.getDataLayout()->getPointerSize();
77 Streamer.SwitchSection(Sec);
78 Streamer.EmitValueToAlignment(TM.getDataLayout()->getPointerABIAlignment());
79 Streamer.EmitSymbolAttribute(Label, MCSA_ELF_TypeObject);
80 const MCExpr *E = MCConstantExpr::Create(Size, getContext());
81 Streamer.EmitELFSize(Label, E);
82 Streamer.EmitLabel(Label);
84 Streamer.EmitSymbolValue(Sym, Size);
87 const MCExpr *TargetLoweringObjectFileELF::getTTypeGlobalReference(
88 const GlobalValue *GV, unsigned Encoding, Mangler &Mang,
89 const TargetMachine &TM, MachineModuleInfo *MMI,
90 MCStreamer &Streamer) const {
92 if (Encoding & dwarf::DW_EH_PE_indirect) {
93 MachineModuleInfoELF &ELFMMI = MMI->getObjFileInfo<MachineModuleInfoELF>();
95 MCSymbol *SSym = getSymbolWithGlobalValueBase(GV, ".DW.stub", Mang, TM);
97 // Add information about the stub reference to ELFMMI so that the stub
98 // gets emitted by the asmprinter.
99 MachineModuleInfoImpl::StubValueTy &StubSym = ELFMMI.getGVStubEntry(SSym);
100 if (!StubSym.getPointer()) {
101 MCSymbol *Sym = TM.getSymbol(GV, Mang);
102 StubSym = MachineModuleInfoImpl::StubValueTy(Sym, !GV->hasLocalLinkage());
105 return TargetLoweringObjectFile::
106 getTTypeReference(MCSymbolRefExpr::Create(SSym, getContext()),
107 Encoding & ~dwarf::DW_EH_PE_indirect, Streamer);
110 return TargetLoweringObjectFile::
111 getTTypeGlobalReference(GV, Encoding, Mang, TM, MMI, Streamer);
115 getELFKindForNamedSection(StringRef Name, SectionKind K) {
116 // N.B.: The defaults used in here are no the same ones used in MC.
117 // We follow gcc, MC follows gas. For example, given ".section .eh_frame",
118 // both gas and MC will produce a section with no flags. Given
119 // section(".eh_frame") gcc will produce:
121 // .section .eh_frame,"a",@progbits
122 if (Name.empty() || Name[0] != '.') return K;
124 // Some lame default implementation based on some magic section names.
125 if (Name == ".bss" ||
126 Name.startswith(".bss.") ||
127 Name.startswith(".gnu.linkonce.b.") ||
128 Name.startswith(".llvm.linkonce.b.") ||
130 Name.startswith(".sbss.") ||
131 Name.startswith(".gnu.linkonce.sb.") ||
132 Name.startswith(".llvm.linkonce.sb."))
133 return SectionKind::getBSS();
135 if (Name == ".tdata" ||
136 Name.startswith(".tdata.") ||
137 Name.startswith(".gnu.linkonce.td.") ||
138 Name.startswith(".llvm.linkonce.td."))
139 return SectionKind::getThreadData();
141 if (Name == ".tbss" ||
142 Name.startswith(".tbss.") ||
143 Name.startswith(".gnu.linkonce.tb.") ||
144 Name.startswith(".llvm.linkonce.tb."))
145 return SectionKind::getThreadBSS();
151 static unsigned getELFSectionType(StringRef Name, SectionKind K) {
153 if (Name == ".init_array")
154 return ELF::SHT_INIT_ARRAY;
156 if (Name == ".fini_array")
157 return ELF::SHT_FINI_ARRAY;
159 if (Name == ".preinit_array")
160 return ELF::SHT_PREINIT_ARRAY;
162 if (K.isBSS() || K.isThreadBSS())
163 return ELF::SHT_NOBITS;
165 return ELF::SHT_PROGBITS;
170 getELFSectionFlags(SectionKind K) {
174 Flags |= ELF::SHF_ALLOC;
177 Flags |= ELF::SHF_EXECINSTR;
180 Flags |= ELF::SHF_WRITE;
182 if (K.isThreadLocal())
183 Flags |= ELF::SHF_TLS;
185 if (K.isMergeableCString() || K.isMergeableConst())
186 Flags |= ELF::SHF_MERGE;
188 if (K.isMergeableCString())
189 Flags |= ELF::SHF_STRINGS;
194 static const Comdat *getELFComdat(const GlobalValue *GV) {
195 const Comdat *C = GV->getComdat();
199 if (C->getSelectionKind() != Comdat::Any)
200 report_fatal_error("ELF COMDATs only support SelectionKind::Any, '" +
201 C->getName() + "' cannot be lowered.");
206 const MCSection *TargetLoweringObjectFileELF::getExplicitSectionGlobal(
207 const GlobalValue *GV, SectionKind Kind, Mangler &Mang,
208 const TargetMachine &TM) const {
209 StringRef SectionName = GV->getSection();
211 // Infer section flags from the section name if we can.
212 Kind = getELFKindForNamedSection(SectionName, Kind);
214 StringRef Group = "";
215 unsigned Flags = getELFSectionFlags(Kind);
216 if (const Comdat *C = getELFComdat(GV)) {
217 Group = C->getName();
218 Flags |= ELF::SHF_GROUP;
220 return getContext().getELFSection(SectionName,
221 getELFSectionType(SectionName, Kind), Flags,
222 Kind, /*EntrySize=*/0, Group);
225 /// getSectionPrefixForGlobal - Return the section prefix name used by options
226 /// FunctionsSections and DataSections.
227 static StringRef getSectionPrefixForGlobal(SectionKind Kind) {
228 if (Kind.isText()) return ".text.";
229 if (Kind.isReadOnly()) return ".rodata.";
230 if (Kind.isBSS()) return ".bss.";
232 if (Kind.isThreadData()) return ".tdata.";
233 if (Kind.isThreadBSS()) return ".tbss.";
235 if (Kind.isDataNoRel()) return ".data.";
236 if (Kind.isDataRelLocal()) return ".data.rel.local.";
237 if (Kind.isDataRel()) return ".data.rel.";
238 if (Kind.isReadOnlyWithRelLocal()) return ".data.rel.ro.local.";
240 assert(Kind.isReadOnlyWithRel() && "Unknown section kind");
241 return ".data.rel.ro.";
244 const MCSection *TargetLoweringObjectFileELF::
245 SelectSectionForGlobal(const GlobalValue *GV, SectionKind Kind,
246 Mangler &Mang, const TargetMachine &TM) const {
247 unsigned Flags = getELFSectionFlags(Kind);
249 // If we have -ffunction-section or -fdata-section then we should emit the
250 // global value to a uniqued section specifically for it.
251 bool EmitUniquedSection = false;
252 if (!(Flags & ELF::SHF_MERGE) && !Kind.isCommon()) {
254 EmitUniquedSection = TM.getFunctionSections();
256 EmitUniquedSection = TM.getDataSections();
259 if (EmitUniquedSection || GV->hasComdat()) {
260 StringRef Prefix = getSectionPrefixForGlobal(Kind);
262 SmallString<128> Name(Prefix);
263 TM.getNameWithPrefix(Name, GV, Mang, true);
265 StringRef Group = "";
266 if (const Comdat *C = getELFComdat(GV)) {
267 Flags |= ELF::SHF_GROUP;
268 Group = C->getName();
271 return getContext().getELFSection(Name.str(),
272 getELFSectionType(Name.str(), Kind),
273 Flags, Kind, 0, Group);
276 if (Kind.isText()) return TextSection;
278 if (Kind.isMergeableCString()) {
280 // We also need alignment here.
281 // FIXME: this is getting the alignment of the character, not the
282 // alignment of the global!
284 TM.getDataLayout()->getPreferredAlignment(cast<GlobalVariable>(GV));
286 const char *SizeSpec = ".rodata.str1.";
287 if (Kind.isMergeable2ByteCString())
288 SizeSpec = ".rodata.str2.";
289 else if (Kind.isMergeable4ByteCString())
290 SizeSpec = ".rodata.str4.";
292 assert(Kind.isMergeable1ByteCString() && "unknown string width");
295 std::string Name = SizeSpec + utostr(Align);
296 return getContext().getELFSection(Name, ELF::SHT_PROGBITS,
303 if (Kind.isMergeableConst()) {
304 if (Kind.isMergeableConst4() && MergeableConst4Section)
305 return MergeableConst4Section;
306 if (Kind.isMergeableConst8() && MergeableConst8Section)
307 return MergeableConst8Section;
308 if (Kind.isMergeableConst16() && MergeableConst16Section)
309 return MergeableConst16Section;
310 return ReadOnlySection; // .const
313 if (Kind.isReadOnly()) return ReadOnlySection;
315 if (Kind.isThreadData()) return TLSDataSection;
316 if (Kind.isThreadBSS()) return TLSBSSSection;
318 // Note: we claim that common symbols are put in BSSSection, but they are
319 // really emitted with the magic .comm directive, which creates a symbol table
320 // entry but not a section.
321 if (Kind.isBSS() || Kind.isCommon()) return BSSSection;
323 if (Kind.isDataNoRel()) return DataSection;
324 if (Kind.isDataRelLocal()) return DataRelLocalSection;
325 if (Kind.isDataRel()) return DataRelSection;
326 if (Kind.isReadOnlyWithRelLocal()) return DataRelROLocalSection;
328 assert(Kind.isReadOnlyWithRel() && "Unknown section kind");
329 return DataRelROSection;
332 /// getSectionForConstant - Given a mergeable constant with the
333 /// specified size and relocation information, return a section that it
334 /// should be placed in.
336 TargetLoweringObjectFileELF::getSectionForConstant(SectionKind Kind,
337 const Constant *C) const {
338 if (Kind.isMergeableConst4() && MergeableConst4Section)
339 return MergeableConst4Section;
340 if (Kind.isMergeableConst8() && MergeableConst8Section)
341 return MergeableConst8Section;
342 if (Kind.isMergeableConst16() && MergeableConst16Section)
343 return MergeableConst16Section;
344 if (Kind.isReadOnly())
345 return ReadOnlySection;
347 if (Kind.isReadOnlyWithRelLocal()) return DataRelROLocalSection;
348 assert(Kind.isReadOnlyWithRel() && "Unknown section kind");
349 return DataRelROSection;
352 static const MCSectionELF *getStaticStructorSection(MCContext &Ctx,
356 const MCSymbol *KeySym) {
359 unsigned Flags = ELF::SHF_ALLOC | ELF::SHF_WRITE;
360 SectionKind Kind = SectionKind::getDataRel();
361 StringRef COMDAT = KeySym ? KeySym->getName() : "";
364 Flags |= ELF::SHF_GROUP;
368 Type = ELF::SHT_INIT_ARRAY;
369 Name = ".init_array";
371 Type = ELF::SHT_FINI_ARRAY;
372 Name = ".fini_array";
374 if (Priority != 65535) {
376 Name += utostr(Priority);
379 // The default scheme is .ctor / .dtor, so we have to invert the priority
385 if (Priority != 65535) {
387 Name += utostr(65535 - Priority);
389 Type = ELF::SHT_PROGBITS;
392 return Ctx.getELFSection(Name, Type, Flags, Kind, 0, COMDAT);
395 const MCSection *TargetLoweringObjectFileELF::getStaticCtorSection(
396 unsigned Priority, const MCSymbol *KeySym) const {
397 return getStaticStructorSection(getContext(), UseInitArray, true, Priority,
401 const MCSection *TargetLoweringObjectFileELF::getStaticDtorSection(
402 unsigned Priority, const MCSymbol *KeySym) const {
403 return getStaticStructorSection(getContext(), UseInitArray, false, Priority,
408 TargetLoweringObjectFileELF::InitializeELF(bool UseInitArray_) {
409 UseInitArray = UseInitArray_;
414 getContext().getELFSection(".init_array", ELF::SHT_INIT_ARRAY,
417 SectionKind::getDataRel());
419 getContext().getELFSection(".fini_array", ELF::SHT_FINI_ARRAY,
422 SectionKind::getDataRel());
425 //===----------------------------------------------------------------------===//
427 //===----------------------------------------------------------------------===//
429 /// getDepLibFromLinkerOpt - Extract the dependent library name from a linker
430 /// option string. Returns StringRef() if the option does not specify a library.
431 StringRef TargetLoweringObjectFileMachO::
432 getDepLibFromLinkerOpt(StringRef LinkerOption) const {
433 const char *LibCmd = "-l";
434 if (LinkerOption.startswith(LibCmd))
435 return LinkerOption.substr(strlen(LibCmd));
439 /// emitModuleFlags - Perform code emission for module flags.
440 void TargetLoweringObjectFileMachO::
441 emitModuleFlags(MCStreamer &Streamer,
442 ArrayRef<Module::ModuleFlagEntry> ModuleFlags,
443 Mangler &Mang, const TargetMachine &TM) const {
444 unsigned VersionVal = 0;
445 unsigned ImageInfoFlags = 0;
446 MDNode *LinkerOptions = nullptr;
447 StringRef SectionVal;
449 for (ArrayRef<Module::ModuleFlagEntry>::iterator
450 i = ModuleFlags.begin(), e = ModuleFlags.end(); i != e; ++i) {
451 const Module::ModuleFlagEntry &MFE = *i;
453 // Ignore flags with 'Require' behavior.
454 if (MFE.Behavior == Module::Require)
457 StringRef Key = MFE.Key->getString();
458 Metadata *Val = MFE.Val;
460 if (Key == "Objective-C Image Info Version") {
461 VersionVal = mdconst::extract<ConstantInt>(Val)->getZExtValue();
462 } else if (Key == "Objective-C Garbage Collection" ||
463 Key == "Objective-C GC Only" ||
464 Key == "Objective-C Is Simulated" ||
465 Key == "Objective-C Image Swift Version") {
466 ImageInfoFlags |= mdconst::extract<ConstantInt>(Val)->getZExtValue();
467 } else if (Key == "Objective-C Image Info Section") {
468 SectionVal = cast<MDString>(Val)->getString();
469 } else if (Key == "Linker Options") {
470 LinkerOptions = cast<MDNode>(Val);
474 // Emit the linker options if present.
476 for (unsigned i = 0, e = LinkerOptions->getNumOperands(); i != e; ++i) {
477 MDNode *MDOptions = cast<MDNode>(LinkerOptions->getOperand(i));
478 SmallVector<std::string, 4> StrOptions;
480 // Convert to strings.
481 for (unsigned ii = 0, ie = MDOptions->getNumOperands(); ii != ie; ++ii) {
482 MDString *MDOption = cast<MDString>(MDOptions->getOperand(ii));
483 StrOptions.push_back(MDOption->getString());
486 Streamer.EmitLinkerOptions(StrOptions);
490 // The section is mandatory. If we don't have it, then we don't have GC info.
491 if (SectionVal.empty()) return;
493 StringRef Segment, Section;
494 unsigned TAA = 0, StubSize = 0;
496 std::string ErrorCode =
497 MCSectionMachO::ParseSectionSpecifier(SectionVal, Segment, Section,
498 TAA, TAAParsed, StubSize);
499 if (!ErrorCode.empty())
500 // If invalid, report the error with report_fatal_error.
501 report_fatal_error("Invalid section specifier '" + Section + "': " +
505 const MCSectionMachO *S =
506 getContext().getMachOSection(Segment, Section, TAA, StubSize,
507 SectionKind::getDataNoRel());
508 Streamer.SwitchSection(S);
509 Streamer.EmitLabel(getContext().
510 GetOrCreateSymbol(StringRef("L_OBJC_IMAGE_INFO")));
511 Streamer.EmitIntValue(VersionVal, 4);
512 Streamer.EmitIntValue(ImageInfoFlags, 4);
513 Streamer.AddBlankLine();
516 static void checkMachOComdat(const GlobalValue *GV) {
517 const Comdat *C = GV->getComdat();
521 report_fatal_error("MachO doesn't support COMDATs, '" + C->getName() +
522 "' cannot be lowered.");
525 const MCSection *TargetLoweringObjectFileMachO::getExplicitSectionGlobal(
526 const GlobalValue *GV, SectionKind Kind, Mangler &Mang,
527 const TargetMachine &TM) const {
528 // Parse the section specifier and create it if valid.
529 StringRef Segment, Section;
530 unsigned TAA = 0, StubSize = 0;
533 checkMachOComdat(GV);
535 std::string ErrorCode =
536 MCSectionMachO::ParseSectionSpecifier(GV->getSection(), Segment, Section,
537 TAA, TAAParsed, StubSize);
538 if (!ErrorCode.empty()) {
539 // If invalid, report the error with report_fatal_error.
540 report_fatal_error("Global variable '" + GV->getName() +
541 "' has an invalid section specifier '" +
542 GV->getSection() + "': " + ErrorCode + ".");
546 const MCSectionMachO *S =
547 getContext().getMachOSection(Segment, Section, TAA, StubSize, Kind);
549 // If TAA wasn't set by ParseSectionSpecifier() above,
550 // use the value returned by getMachOSection() as a default.
552 TAA = S->getTypeAndAttributes();
554 // Okay, now that we got the section, verify that the TAA & StubSize agree.
555 // If the user declared multiple globals with different section flags, we need
556 // to reject it here.
557 if (S->getTypeAndAttributes() != TAA || S->getStubSize() != StubSize) {
558 // If invalid, report the error with report_fatal_error.
559 report_fatal_error("Global variable '" + GV->getName() +
560 "' section type or attributes does not match previous"
561 " section specifier");
567 const MCSection *TargetLoweringObjectFileMachO::
568 SelectSectionForGlobal(const GlobalValue *GV, SectionKind Kind,
569 Mangler &Mang, const TargetMachine &TM) const {
570 checkMachOComdat(GV);
572 // Handle thread local data.
573 if (Kind.isThreadBSS()) return TLSBSSSection;
574 if (Kind.isThreadData()) return TLSDataSection;
577 return GV->isWeakForLinker() ? TextCoalSection : TextSection;
579 // If this is weak/linkonce, put this in a coalescable section, either in text
580 // or data depending on if it is writable.
581 if (GV->isWeakForLinker()) {
582 if (Kind.isReadOnly())
583 return ConstTextCoalSection;
584 return DataCoalSection;
587 // FIXME: Alignment check should be handled by section classifier.
588 if (Kind.isMergeable1ByteCString() &&
589 TM.getDataLayout()->getPreferredAlignment(cast<GlobalVariable>(GV)) < 32)
590 return CStringSection;
592 // Do not put 16-bit arrays in the UString section if they have an
593 // externally visible label, this runs into issues with certain linker
595 if (Kind.isMergeable2ByteCString() && !GV->hasExternalLinkage() &&
596 TM.getDataLayout()->getPreferredAlignment(cast<GlobalVariable>(GV)) < 32)
597 return UStringSection;
599 // With MachO only variables whose corresponding symbol starts with 'l' or
600 // 'L' can be merged, so we only try merging GVs with private linkage.
601 if (GV->hasPrivateLinkage() && Kind.isMergeableConst()) {
602 if (Kind.isMergeableConst4())
603 return FourByteConstantSection;
604 if (Kind.isMergeableConst8())
605 return EightByteConstantSection;
606 if (Kind.isMergeableConst16())
607 return SixteenByteConstantSection;
610 // Otherwise, if it is readonly, but not something we can specially optimize,
611 // just drop it in .const.
612 if (Kind.isReadOnly())
613 return ReadOnlySection;
615 // If this is marked const, put it into a const section. But if the dynamic
616 // linker needs to write to it, put it in the data segment.
617 if (Kind.isReadOnlyWithRel())
618 return ConstDataSection;
620 // Put zero initialized globals with strong external linkage in the
621 // DATA, __common section with the .zerofill directive.
622 if (Kind.isBSSExtern())
623 return DataCommonSection;
625 // Put zero initialized globals with local linkage in __DATA,__bss directive
626 // with the .zerofill directive (aka .lcomm).
627 if (Kind.isBSSLocal())
628 return DataBSSSection;
630 // Otherwise, just drop the variable in the normal data section.
635 TargetLoweringObjectFileMachO::getSectionForConstant(SectionKind Kind,
636 const Constant *C) const {
637 // If this constant requires a relocation, we have to put it in the data
638 // segment, not in the text segment.
639 if (Kind.isDataRel() || Kind.isReadOnlyWithRel())
640 return ConstDataSection;
642 if (Kind.isMergeableConst4())
643 return FourByteConstantSection;
644 if (Kind.isMergeableConst8())
645 return EightByteConstantSection;
646 if (Kind.isMergeableConst16())
647 return SixteenByteConstantSection;
648 return ReadOnlySection; // .const
651 const MCExpr *TargetLoweringObjectFileMachO::getTTypeGlobalReference(
652 const GlobalValue *GV, unsigned Encoding, Mangler &Mang,
653 const TargetMachine &TM, MachineModuleInfo *MMI,
654 MCStreamer &Streamer) const {
655 // The mach-o version of this method defaults to returning a stub reference.
657 if (Encoding & DW_EH_PE_indirect) {
658 MachineModuleInfoMachO &MachOMMI =
659 MMI->getObjFileInfo<MachineModuleInfoMachO>();
662 getSymbolWithGlobalValueBase(GV, "$non_lazy_ptr", Mang, TM);
664 // Add information about the stub reference to MachOMMI so that the stub
665 // gets emitted by the asmprinter.
666 MachineModuleInfoImpl::StubValueTy &StubSym =
667 GV->hasHiddenVisibility() ? MachOMMI.getHiddenGVStubEntry(SSym) :
668 MachOMMI.getGVStubEntry(SSym);
669 if (!StubSym.getPointer()) {
670 MCSymbol *Sym = TM.getSymbol(GV, Mang);
671 StubSym = MachineModuleInfoImpl::StubValueTy(Sym, !GV->hasLocalLinkage());
674 return TargetLoweringObjectFile::
675 getTTypeReference(MCSymbolRefExpr::Create(SSym, getContext()),
676 Encoding & ~dwarf::DW_EH_PE_indirect, Streamer);
679 return TargetLoweringObjectFile::getTTypeGlobalReference(GV, Encoding, Mang,
683 MCSymbol *TargetLoweringObjectFileMachO::getCFIPersonalitySymbol(
684 const GlobalValue *GV, Mangler &Mang, const TargetMachine &TM,
685 MachineModuleInfo *MMI) const {
686 // The mach-o version of this method defaults to returning a stub reference.
687 MachineModuleInfoMachO &MachOMMI =
688 MMI->getObjFileInfo<MachineModuleInfoMachO>();
690 MCSymbol *SSym = getSymbolWithGlobalValueBase(GV, "$non_lazy_ptr", Mang, TM);
692 // Add information about the stub reference to MachOMMI so that the stub
693 // gets emitted by the asmprinter.
694 MachineModuleInfoImpl::StubValueTy &StubSym = MachOMMI.getGVStubEntry(SSym);
695 if (!StubSym.getPointer()) {
696 MCSymbol *Sym = TM.getSymbol(GV, Mang);
697 StubSym = MachineModuleInfoImpl::StubValueTy(Sym, !GV->hasLocalLinkage());
703 //===----------------------------------------------------------------------===//
705 //===----------------------------------------------------------------------===//
708 getCOFFSectionFlags(SectionKind K) {
713 COFF::IMAGE_SCN_MEM_DISCARDABLE;
716 COFF::IMAGE_SCN_MEM_EXECUTE |
717 COFF::IMAGE_SCN_MEM_READ |
718 COFF::IMAGE_SCN_CNT_CODE;
721 COFF::IMAGE_SCN_CNT_UNINITIALIZED_DATA |
722 COFF::IMAGE_SCN_MEM_READ |
723 COFF::IMAGE_SCN_MEM_WRITE;
724 else if (K.isThreadLocal())
726 COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
727 COFF::IMAGE_SCN_MEM_READ |
728 COFF::IMAGE_SCN_MEM_WRITE;
729 else if (K.isReadOnly() || K.isReadOnlyWithRel())
731 COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
732 COFF::IMAGE_SCN_MEM_READ;
733 else if (K.isWriteable())
735 COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
736 COFF::IMAGE_SCN_MEM_READ |
737 COFF::IMAGE_SCN_MEM_WRITE;
742 static const GlobalValue *getComdatGVForCOFF(const GlobalValue *GV) {
743 const Comdat *C = GV->getComdat();
744 assert(C && "expected GV to have a Comdat!");
746 StringRef ComdatGVName = C->getName();
747 const GlobalValue *ComdatGV = GV->getParent()->getNamedValue(ComdatGVName);
749 report_fatal_error("Associative COMDAT symbol '" + ComdatGVName +
750 "' does not exist.");
752 if (ComdatGV->getComdat() != C)
753 report_fatal_error("Associative COMDAT symbol '" + ComdatGVName +
754 "' is not a key for its COMDAT.");
759 static int getSelectionForCOFF(const GlobalValue *GV) {
760 if (const Comdat *C = GV->getComdat()) {
761 const GlobalValue *ComdatKey = getComdatGVForCOFF(GV);
762 if (const auto *GA = dyn_cast<GlobalAlias>(ComdatKey))
763 ComdatKey = GA->getBaseObject();
764 if (ComdatKey == GV) {
765 switch (C->getSelectionKind()) {
767 return COFF::IMAGE_COMDAT_SELECT_ANY;
768 case Comdat::ExactMatch:
769 return COFF::IMAGE_COMDAT_SELECT_EXACT_MATCH;
770 case Comdat::Largest:
771 return COFF::IMAGE_COMDAT_SELECT_LARGEST;
772 case Comdat::NoDuplicates:
773 return COFF::IMAGE_COMDAT_SELECT_NODUPLICATES;
774 case Comdat::SameSize:
775 return COFF::IMAGE_COMDAT_SELECT_SAME_SIZE;
778 return COFF::IMAGE_COMDAT_SELECT_ASSOCIATIVE;
780 } else if (GV->isWeakForLinker()) {
781 return COFF::IMAGE_COMDAT_SELECT_ANY;
786 const MCSection *TargetLoweringObjectFileCOFF::getExplicitSectionGlobal(
787 const GlobalValue *GV, SectionKind Kind, Mangler &Mang,
788 const TargetMachine &TM) const {
790 unsigned Characteristics = getCOFFSectionFlags(Kind);
791 StringRef Name = GV->getSection();
792 StringRef COMDATSymName = "";
793 if (GV->hasComdat()) {
794 Selection = getSelectionForCOFF(GV);
795 const GlobalValue *ComdatGV;
796 if (Selection == COFF::IMAGE_COMDAT_SELECT_ASSOCIATIVE)
797 ComdatGV = getComdatGVForCOFF(GV);
801 if (!ComdatGV->hasPrivateLinkage()) {
802 MCSymbol *Sym = TM.getSymbol(ComdatGV, Mang);
803 COMDATSymName = Sym->getName();
804 Characteristics |= COFF::IMAGE_SCN_LNK_COMDAT;
809 return getContext().getCOFFSection(Name,
816 static const char *getCOFFSectionNameForUniqueGlobal(SectionKind Kind) {
821 if (Kind.isThreadLocal())
823 if (Kind.isReadOnly() || Kind.isReadOnlyWithRel())
829 const MCSection *TargetLoweringObjectFileCOFF::
830 SelectSectionForGlobal(const GlobalValue *GV, SectionKind Kind,
831 Mangler &Mang, const TargetMachine &TM) const {
832 // If we have -ffunction-sections then we should emit the global value to a
833 // uniqued section specifically for it.
834 bool EmitUniquedSection;
836 EmitUniquedSection = TM.getFunctionSections();
838 EmitUniquedSection = TM.getDataSections();
840 if ((EmitUniquedSection && !Kind.isCommon()) || GV->hasComdat()) {
841 const char *Name = getCOFFSectionNameForUniqueGlobal(Kind);
842 unsigned Characteristics = getCOFFSectionFlags(Kind);
844 Characteristics |= COFF::IMAGE_SCN_LNK_COMDAT;
845 int Selection = getSelectionForCOFF(GV);
847 Selection = COFF::IMAGE_COMDAT_SELECT_NODUPLICATES;
848 const GlobalValue *ComdatGV;
850 ComdatGV = getComdatGVForCOFF(GV);
854 if (!ComdatGV->hasPrivateLinkage()) {
855 MCSymbol *Sym = TM.getSymbol(ComdatGV, Mang);
856 StringRef COMDATSymName = Sym->getName();
857 return getContext().getCOFFSection(Name, Characteristics, Kind,
858 COMDATSymName, Selection);
865 if (Kind.isThreadLocal())
866 return TLSDataSection;
868 if (Kind.isReadOnly() || Kind.isReadOnlyWithRel())
869 return ReadOnlySection;
871 // Note: we claim that common symbols are put in BSSSection, but they are
872 // really emitted with the magic .comm directive, which creates a symbol table
873 // entry but not a section.
874 if (Kind.isBSS() || Kind.isCommon())
880 StringRef TargetLoweringObjectFileCOFF::
881 getDepLibFromLinkerOpt(StringRef LinkerOption) const {
882 const char *LibCmd = "/DEFAULTLIB:";
883 if (LinkerOption.startswith(LibCmd))
884 return LinkerOption.substr(strlen(LibCmd));
888 void TargetLoweringObjectFileCOFF::
889 emitModuleFlags(MCStreamer &Streamer,
890 ArrayRef<Module::ModuleFlagEntry> ModuleFlags,
891 Mangler &Mang, const TargetMachine &TM) const {
892 MDNode *LinkerOptions = nullptr;
894 // Look for the "Linker Options" flag, since it's the only one we support.
895 for (ArrayRef<Module::ModuleFlagEntry>::iterator
896 i = ModuleFlags.begin(), e = ModuleFlags.end(); i != e; ++i) {
897 const Module::ModuleFlagEntry &MFE = *i;
898 StringRef Key = MFE.Key->getString();
899 Metadata *Val = MFE.Val;
900 if (Key == "Linker Options") {
901 LinkerOptions = cast<MDNode>(Val);
908 // Emit the linker options to the linker .drectve section. According to the
909 // spec, this section is a space-separated string containing flags for linker.
910 const MCSection *Sec = getDrectveSection();
911 Streamer.SwitchSection(Sec);
912 for (unsigned i = 0, e = LinkerOptions->getNumOperands(); i != e; ++i) {
913 MDNode *MDOptions = cast<MDNode>(LinkerOptions->getOperand(i));
914 for (unsigned ii = 0, ie = MDOptions->getNumOperands(); ii != ie; ++ii) {
915 MDString *MDOption = cast<MDString>(MDOptions->getOperand(ii));
916 StringRef Op = MDOption->getString();
917 // Lead with a space for consistency with our dllexport implementation.
918 std::string Escaped(" ");
919 if (!Op.startswith("\"") && (Op.find(" ") != StringRef::npos)) {
920 // The PE-COFF spec says args with spaces must be quoted. It doesn't say
921 // how to escape quotes, but it probably uses this algorithm:
922 // http://msdn.microsoft.com/en-us/library/17w5ykft(v=vs.85).aspx
923 // FIXME: Reuse escaping code from Support/Windows/Program.inc
924 Escaped.push_back('\"');
926 Escaped.push_back('\"');
930 Streamer.EmitBytes(Escaped);
935 const MCSection *TargetLoweringObjectFileCOFF::getStaticCtorSection(
936 unsigned Priority, const MCSymbol *KeySym) const {
937 return getContext().getAssociativeCOFFSection(
938 cast<MCSectionCOFF>(StaticCtorSection), KeySym);
941 const MCSection *TargetLoweringObjectFileCOFF::getStaticDtorSection(
942 unsigned Priority, const MCSymbol *KeySym) const {
943 return getContext().getAssociativeCOFFSection(
944 cast<MCSectionCOFF>(StaticDtorSection), KeySym);