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 Streamer.SwitchSection(Sec);
81 Streamer.EmitValueToAlignment(8);
82 Streamer.EmitSymbolAttribute(Label, MCSA_ELF_TypeObject);
83 const MCExpr *E = MCConstantExpr::Create(8, getContext());
84 Streamer.EmitELFSize(Label, E);
85 Streamer.EmitLabel(Label);
87 unsigned Size = TM.getTargetData()->getPointerSize();
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.";
192 if (Kind.isThreadData()) return ".tdata.";
193 if (Kind.isThreadBSS()) return ".tbss.";
195 if (Kind.isDataNoRel()) return ".data.";
196 if (Kind.isDataRelLocal()) return ".data.rel.local.";
197 if (Kind.isDataRel()) return ".data.rel.";
198 if (Kind.isReadOnlyWithRelLocal()) return ".data.rel.ro.local.";
200 assert(Kind.isReadOnlyWithRel() && "Unknown section kind");
201 return ".data.rel.ro.";
205 const MCSection *TargetLoweringObjectFileELF::
206 SelectSectionForGlobal(const GlobalValue *GV, SectionKind Kind,
207 Mangler *Mang, const TargetMachine &TM) const {
208 // If we have -ffunction-section or -fdata-section then we should emit the
209 // global value to a uniqued section specifically for it.
210 bool EmitUniquedSection;
212 EmitUniquedSection = TM.getFunctionSections();
214 EmitUniquedSection = TM.getDataSections();
216 // If this global is linkonce/weak and the target handles this by emitting it
217 // into a 'uniqued' section name, create and return the section now.
218 if ((GV->isWeakForLinker() || EmitUniquedSection) &&
219 !Kind.isCommon() && !Kind.isBSS()) {
221 Prefix = getSectionPrefixForGlobal(Kind);
223 SmallString<128> Name(Prefix, Prefix+strlen(Prefix));
224 MCSymbol *Sym = Mang->getSymbol(GV);
225 Name.append(Sym->getName().begin(), Sym->getName().end());
226 StringRef Group = "";
227 unsigned Flags = getELFSectionFlags(Kind);
228 if (GV->isWeakForLinker()) {
229 Group = Sym->getName();
230 Flags |= ELF::SHF_GROUP;
233 return getContext().getELFSection(Name.str(),
234 getELFSectionType(Name.str(), Kind),
235 Flags, Kind, 0, Group);
238 if (Kind.isText()) return TextSection;
240 if (Kind.isMergeable1ByteCString() ||
241 Kind.isMergeable2ByteCString() ||
242 Kind.isMergeable4ByteCString()) {
244 // We also need alignment here.
245 // FIXME: this is getting the alignment of the character, not the
246 // alignment of the global!
248 TM.getTargetData()->getPreferredAlignment(cast<GlobalVariable>(GV));
250 const char *SizeSpec = ".rodata.str1.";
251 if (Kind.isMergeable2ByteCString())
252 SizeSpec = ".rodata.str2.";
253 else if (Kind.isMergeable4ByteCString())
254 SizeSpec = ".rodata.str4.";
256 assert(Kind.isMergeable1ByteCString() && "unknown string width");
259 std::string Name = SizeSpec + utostr(Align);
260 return getContext().getELFSection(Name, ELF::SHT_PROGBITS,
267 if (Kind.isMergeableConst()) {
268 if (Kind.isMergeableConst4() && MergeableConst4Section)
269 return MergeableConst4Section;
270 if (Kind.isMergeableConst8() && MergeableConst8Section)
271 return MergeableConst8Section;
272 if (Kind.isMergeableConst16() && MergeableConst16Section)
273 return MergeableConst16Section;
274 return ReadOnlySection; // .const
277 if (Kind.isReadOnly()) return ReadOnlySection;
279 if (Kind.isThreadData()) return TLSDataSection;
280 if (Kind.isThreadBSS()) return TLSBSSSection;
282 // Note: we claim that common symbols are put in BSSSection, but they are
283 // really emitted with the magic .comm directive, which creates a symbol table
284 // entry but not a section.
285 if (Kind.isBSS() || Kind.isCommon()) return BSSSection;
287 if (Kind.isDataNoRel()) return DataSection;
288 if (Kind.isDataRelLocal()) return DataRelLocalSection;
289 if (Kind.isDataRel()) return DataRelSection;
290 if (Kind.isReadOnlyWithRelLocal()) return DataRelROLocalSection;
292 assert(Kind.isReadOnlyWithRel() && "Unknown section kind");
293 return DataRelROSection;
296 /// getSectionForConstant - Given a mergeable constant with the
297 /// specified size and relocation information, return a section that it
298 /// should be placed in.
299 const MCSection *TargetLoweringObjectFileELF::
300 getSectionForConstant(SectionKind Kind) const {
301 if (Kind.isMergeableConst4() && MergeableConst4Section)
302 return MergeableConst4Section;
303 if (Kind.isMergeableConst8() && MergeableConst8Section)
304 return MergeableConst8Section;
305 if (Kind.isMergeableConst16() && MergeableConst16Section)
306 return MergeableConst16Section;
307 if (Kind.isReadOnly())
308 return ReadOnlySection;
310 if (Kind.isReadOnlyWithRelLocal()) return DataRelROLocalSection;
311 assert(Kind.isReadOnlyWithRel() && "Unknown section kind");
312 return DataRelROSection;
315 const MCExpr *TargetLoweringObjectFileELF::
316 getExprForDwarfGlobalReference(const GlobalValue *GV, Mangler *Mang,
317 MachineModuleInfo *MMI,
318 unsigned Encoding, MCStreamer &Streamer) const {
320 if (Encoding & dwarf::DW_EH_PE_indirect) {
321 MachineModuleInfoELF &ELFMMI = MMI->getObjFileInfo<MachineModuleInfoELF>();
323 SmallString<128> Name;
324 Mang->getNameWithPrefix(Name, GV, true);
327 // Add information about the stub reference to ELFMMI so that the stub
328 // gets emitted by the asmprinter.
329 MCSymbol *SSym = getContext().GetOrCreateSymbol(Name.str());
330 MachineModuleInfoImpl::StubValueTy &StubSym = ELFMMI.getGVStubEntry(SSym);
331 if (StubSym.getPointer() == 0) {
332 MCSymbol *Sym = Mang->getSymbol(GV);
333 StubSym = MachineModuleInfoImpl::StubValueTy(Sym, !GV->hasLocalLinkage());
336 return TargetLoweringObjectFile::
337 getExprForDwarfReference(SSym, Encoding & ~dwarf::DW_EH_PE_indirect, Streamer);
340 return TargetLoweringObjectFile::
341 getExprForDwarfGlobalReference(GV, Mang, MMI, Encoding, Streamer);
345 TargetLoweringObjectFileELF::getStaticCtorSection(unsigned Priority) const {
346 // The default scheme is .ctor / .dtor, so we have to invert the priority
348 if (Priority == 65535)
349 return StaticCtorSection;
351 std::string Name = std::string(".ctors.") + utostr(65535 - Priority);
352 return getContext().getELFSection(Name, ELF::SHT_PROGBITS,
353 ELF::SHF_ALLOC |ELF::SHF_WRITE,
354 SectionKind::getDataRel());
358 TargetLoweringObjectFileELF::getStaticDtorSection(unsigned Priority) const {
359 // The default scheme is .ctor / .dtor, so we have to invert the priority
361 if (Priority == 65535)
362 return StaticDtorSection;
364 std::string Name = std::string(".dtors.") + utostr(65535 - Priority);
365 return getContext().getELFSection(Name, ELF::SHT_PROGBITS,
366 ELF::SHF_ALLOC |ELF::SHF_WRITE,
367 SectionKind::getDataRel());
370 //===----------------------------------------------------------------------===//
372 //===----------------------------------------------------------------------===//
374 /// emitModuleFlags - Emit the module flags that specify the garbage collection
376 void TargetLoweringObjectFileMachO::
377 emitModuleFlags(MCStreamer &Streamer, NamedMDNode *ModFlags,
378 Mangler *Mang, const TargetMachine &TM) const {
379 StringRef Version("Objective-C Image Info Version");
380 StringRef SectionSpec("Objective-C Image Info Section");
381 StringRef GC("Objective-C Garbage Collection");
382 StringRef GCOnly("Objective-C GC Only");
384 unsigned VersionVal = 0;
385 unsigned GCFlags = 0;
388 for (unsigned i = 0, e = ModFlags->getNumOperands(); i != e; ++i) {
389 MDNode *Flag = ModFlags->getOperand(i);
390 Value *Behavior = Flag->getOperand(0);
392 // Ignore flags with 'Require' behavior.
393 if (cast<ConstantInt>(Behavior)->getZExtValue() == Module::Require)
396 Value *Key = Flag->getOperand(1);
397 Value *Val = Flag->getOperand(2);
399 StringRef KeyStr = cast<MDString>(Key)->getString();
401 if (KeyStr == Version)
402 VersionVal = cast<ConstantInt>(Val)->getZExtValue();
403 else if (KeyStr == GC || KeyStr == GCOnly)
404 GCFlags |= cast<ConstantInt>(Val)->getZExtValue();
405 else if (KeyStr == SectionSpec)
406 Section = cast<MDString>(Val)->getString();
409 // The section is mandatory. If we don't have it, then we don't have image
411 if (Section.empty()) return;
413 uint32_t Values[2] = { VersionVal, GCFlags };
414 Module *M = ModFlags->getParent();
415 Constant *Init = ConstantDataArray::get(M->getContext(), Values);
416 GlobalVariable *GV = new GlobalVariable(*M, Init->getType(), false,
417 GlobalValue::InternalLinkage, Init,
418 "\01L_OBJC_IMAGE_INFO");
419 GV->setSection(Section);
421 MCSymbol *GVSym = Mang->getSymbol(GV);
422 SectionKind GVKind = TargetLoweringObjectFile::getKindForGlobal(GV, TM);
423 const MCSection *TheSection = SectionForGlobal(GV, GVKind, Mang, TM);
425 Streamer.SwitchSection(TheSection);
426 Streamer.EmitLabel(GVSym);
428 Streamer.EmitIntValue(VersionVal, 4);
429 Streamer.EmitIntValue(GCFlags, 4);
430 Streamer.AddBlankLine();
433 const MCSection *TargetLoweringObjectFileMachO::
434 getExplicitSectionGlobal(const GlobalValue *GV, SectionKind Kind,
435 Mangler *Mang, const TargetMachine &TM) const {
436 // Parse the section specifier and create it if valid.
437 StringRef Segment, Section;
438 unsigned TAA = 0, StubSize = 0;
440 std::string ErrorCode =
441 MCSectionMachO::ParseSectionSpecifier(GV->getSection(), Segment, Section,
442 TAA, TAAParsed, StubSize);
443 if (!ErrorCode.empty()) {
444 // If invalid, report the error with report_fatal_error.
445 report_fatal_error("Global variable '" + GV->getName() +
446 "' has an invalid section specifier '" +
447 GV->getSection() + "': " + ErrorCode + ".");
451 const MCSectionMachO *S =
452 getContext().getMachOSection(Segment, Section, TAA, StubSize, Kind);
454 // If TAA wasn't set by ParseSectionSpecifier() above,
455 // use the value returned by getMachOSection() as a default.
457 TAA = S->getTypeAndAttributes();
459 // Okay, now that we got the section, verify that the TAA & StubSize agree.
460 // If the user declared multiple globals with different section flags, we need
461 // to reject it here.
462 if (S->getTypeAndAttributes() != TAA || S->getStubSize() != StubSize) {
463 // If invalid, report the error with report_fatal_error.
464 report_fatal_error("Global variable '" + GV->getName() +
465 "' section type or attributes does not match previous"
466 " section specifier");
472 const MCSection *TargetLoweringObjectFileMachO::
473 SelectSectionForGlobal(const GlobalValue *GV, SectionKind Kind,
474 Mangler *Mang, const TargetMachine &TM) const {
476 // Handle thread local data.
477 if (Kind.isThreadBSS()) return TLSBSSSection;
478 if (Kind.isThreadData()) return TLSDataSection;
481 return GV->isWeakForLinker() ? TextCoalSection : TextSection;
483 // If this is weak/linkonce, put this in a coalescable section, either in text
484 // or data depending on if it is writable.
485 if (GV->isWeakForLinker()) {
486 if (Kind.isReadOnly())
487 return ConstTextCoalSection;
488 return DataCoalSection;
491 // FIXME: Alignment check should be handled by section classifier.
492 if (Kind.isMergeable1ByteCString() &&
493 TM.getTargetData()->getPreferredAlignment(cast<GlobalVariable>(GV)) < 32)
494 return CStringSection;
496 // Do not put 16-bit arrays in the UString section if they have an
497 // externally visible label, this runs into issues with certain linker
499 if (Kind.isMergeable2ByteCString() && !GV->hasExternalLinkage() &&
500 TM.getTargetData()->getPreferredAlignment(cast<GlobalVariable>(GV)) < 32)
501 return UStringSection;
503 if (Kind.isMergeableConst()) {
504 if (Kind.isMergeableConst4())
505 return FourByteConstantSection;
506 if (Kind.isMergeableConst8())
507 return EightByteConstantSection;
508 if (Kind.isMergeableConst16() && SixteenByteConstantSection)
509 return SixteenByteConstantSection;
512 // Otherwise, if it is readonly, but not something we can specially optimize,
513 // just drop it in .const.
514 if (Kind.isReadOnly())
515 return ReadOnlySection;
517 // If this is marked const, put it into a const section. But if the dynamic
518 // linker needs to write to it, put it in the data segment.
519 if (Kind.isReadOnlyWithRel())
520 return ConstDataSection;
522 // Put zero initialized globals with strong external linkage in the
523 // DATA, __common section with the .zerofill directive.
524 if (Kind.isBSSExtern())
525 return DataCommonSection;
527 // Put zero initialized globals with local linkage in __DATA,__bss directive
528 // with the .zerofill directive (aka .lcomm).
529 if (Kind.isBSSLocal())
530 return DataBSSSection;
532 // Otherwise, just drop the variable in the normal data section.
537 TargetLoweringObjectFileMachO::getSectionForConstant(SectionKind Kind) const {
538 // If this constant requires a relocation, we have to put it in the data
539 // segment, not in the text segment.
540 if (Kind.isDataRel() || Kind.isReadOnlyWithRel())
541 return ConstDataSection;
543 if (Kind.isMergeableConst4())
544 return FourByteConstantSection;
545 if (Kind.isMergeableConst8())
546 return EightByteConstantSection;
547 if (Kind.isMergeableConst16() && SixteenByteConstantSection)
548 return SixteenByteConstantSection;
549 return ReadOnlySection; // .const
552 /// shouldEmitUsedDirectiveFor - This hook allows targets to selectively decide
553 /// not to emit the UsedDirective for some symbols in llvm.used.
554 // FIXME: REMOVE this (rdar://7071300)
555 bool TargetLoweringObjectFileMachO::
556 shouldEmitUsedDirectiveFor(const GlobalValue *GV, Mangler *Mang) const {
557 /// On Darwin, internally linked data beginning with "L" or "l" does not have
558 /// the directive emitted (this occurs in ObjC metadata).
559 if (!GV) return false;
561 // Check whether the mangled name has the "Private" or "LinkerPrivate" prefix.
562 if (GV->hasLocalLinkage() && !isa<Function>(GV)) {
563 // FIXME: ObjC metadata is currently emitted as internal symbols that have
564 // \1L and \0l prefixes on them. Fix them to be Private/LinkerPrivate and
565 // this horrible hack can go away.
566 MCSymbol *Sym = Mang->getSymbol(GV);
567 if (Sym->getName()[0] == 'L' || Sym->getName()[0] == 'l')
574 const MCExpr *TargetLoweringObjectFileMachO::
575 getExprForDwarfGlobalReference(const GlobalValue *GV, Mangler *Mang,
576 MachineModuleInfo *MMI, unsigned Encoding,
577 MCStreamer &Streamer) const {
578 // The mach-o version of this method defaults to returning a stub reference.
580 if (Encoding & DW_EH_PE_indirect) {
581 MachineModuleInfoMachO &MachOMMI =
582 MMI->getObjFileInfo<MachineModuleInfoMachO>();
584 SmallString<128> Name;
585 Mang->getNameWithPrefix(Name, GV, true);
586 Name += "$non_lazy_ptr";
588 // Add information about the stub reference to MachOMMI so that the stub
589 // gets emitted by the asmprinter.
590 MCSymbol *SSym = getContext().GetOrCreateSymbol(Name.str());
591 MachineModuleInfoImpl::StubValueTy &StubSym =
592 GV->hasHiddenVisibility() ? MachOMMI.getHiddenGVStubEntry(SSym) :
593 MachOMMI.getGVStubEntry(SSym);
594 if (StubSym.getPointer() == 0) {
595 MCSymbol *Sym = Mang->getSymbol(GV);
596 StubSym = MachineModuleInfoImpl::StubValueTy(Sym, !GV->hasLocalLinkage());
599 return TargetLoweringObjectFile::
600 getExprForDwarfReference(SSym, Encoding & ~dwarf::DW_EH_PE_indirect, Streamer);
603 return TargetLoweringObjectFile::
604 getExprForDwarfGlobalReference(GV, Mang, MMI, Encoding, Streamer);
607 MCSymbol *TargetLoweringObjectFileMachO::
608 getCFIPersonalitySymbol(const GlobalValue *GV, Mangler *Mang,
609 MachineModuleInfo *MMI) const {
610 // The mach-o version of this method defaults to returning a stub reference.
611 MachineModuleInfoMachO &MachOMMI =
612 MMI->getObjFileInfo<MachineModuleInfoMachO>();
614 SmallString<128> Name;
615 Mang->getNameWithPrefix(Name, GV, true);
616 Name += "$non_lazy_ptr";
618 // Add information about the stub reference to MachOMMI so that the stub
619 // gets emitted by the asmprinter.
620 MCSymbol *SSym = getContext().GetOrCreateSymbol(Name.str());
621 MachineModuleInfoImpl::StubValueTy &StubSym = MachOMMI.getGVStubEntry(SSym);
622 if (StubSym.getPointer() == 0) {
623 MCSymbol *Sym = Mang->getSymbol(GV);
624 StubSym = MachineModuleInfoImpl::StubValueTy(Sym, !GV->hasLocalLinkage());
630 //===----------------------------------------------------------------------===//
632 //===----------------------------------------------------------------------===//
635 getCOFFSectionFlags(SectionKind K) {
640 COFF::IMAGE_SCN_MEM_DISCARDABLE;
643 COFF::IMAGE_SCN_MEM_EXECUTE |
644 COFF::IMAGE_SCN_MEM_READ |
645 COFF::IMAGE_SCN_CNT_CODE;
648 COFF::IMAGE_SCN_CNT_UNINITIALIZED_DATA |
649 COFF::IMAGE_SCN_MEM_READ |
650 COFF::IMAGE_SCN_MEM_WRITE;
651 else if (K.isThreadLocal())
653 COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
654 COFF::IMAGE_SCN_MEM_READ |
655 COFF::IMAGE_SCN_MEM_WRITE;
656 else if (K.isReadOnly())
658 COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
659 COFF::IMAGE_SCN_MEM_READ;
660 else if (K.isWriteable())
662 COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
663 COFF::IMAGE_SCN_MEM_READ |
664 COFF::IMAGE_SCN_MEM_WRITE;
669 const MCSection *TargetLoweringObjectFileCOFF::
670 getExplicitSectionGlobal(const GlobalValue *GV, SectionKind Kind,
671 Mangler *Mang, const TargetMachine &TM) const {
672 return getContext().getCOFFSection(GV->getSection(),
673 getCOFFSectionFlags(Kind),
677 static const char *getCOFFSectionPrefixForUniqueGlobal(SectionKind Kind) {
682 if (Kind.isThreadLocal())
684 if (Kind.isWriteable())
690 const MCSection *TargetLoweringObjectFileCOFF::
691 SelectSectionForGlobal(const GlobalValue *GV, SectionKind Kind,
692 Mangler *Mang, const TargetMachine &TM) const {
694 // If this global is linkonce/weak and the target handles this by emitting it
695 // into a 'uniqued' section name, create and return the section now.
696 if (GV->isWeakForLinker()) {
697 const char *Prefix = getCOFFSectionPrefixForUniqueGlobal(Kind);
698 SmallString<128> Name(Prefix, Prefix+strlen(Prefix));
699 MCSymbol *Sym = Mang->getSymbol(GV);
700 Name.append(Sym->getName().begin() + 1, Sym->getName().end());
702 unsigned Characteristics = getCOFFSectionFlags(Kind);
704 Characteristics |= COFF::IMAGE_SCN_LNK_COMDAT;
706 return getContext().getCOFFSection(Name.str(), Characteristics,
707 COFF::IMAGE_COMDAT_SELECT_ANY, Kind);
711 return getTextSection();
713 if (Kind.isThreadLocal())
714 return getTLSDataSection();
716 return getDataSection();