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/CodeGen/MachineModuleInfoImpls.h"
21 #include "llvm/MC/MCContext.h"
22 #include "llvm/MC/MCExpr.h"
23 #include "llvm/MC/MCSectionMachO.h"
24 #include "llvm/MC/MCSectionELF.h"
25 #include "llvm/MC/MCSectionCOFF.h"
26 #include "llvm/MC/MCStreamer.h"
27 #include "llvm/MC/MCSymbol.h"
28 #include "llvm/Target/Mangler.h"
29 #include "llvm/Target/TargetData.h"
30 #include "llvm/Target/TargetMachine.h"
31 #include "llvm/Target/TargetOptions.h"
32 #include "llvm/Support/Dwarf.h"
33 #include "llvm/Support/ELF.h"
34 #include "llvm/Support/ErrorHandling.h"
35 #include "llvm/Support/raw_ostream.h"
36 #include "llvm/ADT/SmallString.h"
37 #include "llvm/ADT/StringExtras.h"
38 #include "llvm/ADT/Triple.h"
40 using namespace dwarf;
42 //===----------------------------------------------------------------------===//
44 //===----------------------------------------------------------------------===//
46 void TargetLoweringObjectFileELF::Initialize(MCContext &Ctx,
47 const TargetMachine &TM) {
48 TargetLoweringObjectFile::Initialize(Ctx, TM);
51 getContext().getELFSection(".bss", ELF::SHT_NOBITS,
52 ELF::SHF_WRITE |ELF::SHF_ALLOC,
53 SectionKind::getBSS());
56 getContext().getELFSection(".text", ELF::SHT_PROGBITS,
59 SectionKind::getText());
62 getContext().getELFSection(".data", ELF::SHT_PROGBITS,
63 ELF::SHF_WRITE |ELF::SHF_ALLOC,
64 SectionKind::getDataRel());
67 getContext().getELFSection(".rodata", ELF::SHT_PROGBITS,
69 SectionKind::getReadOnly());
72 getContext().getELFSection(".tdata", ELF::SHT_PROGBITS,
73 ELF::SHF_ALLOC | ELF::SHF_TLS |
75 SectionKind::getThreadData());
78 getContext().getELFSection(".tbss", ELF::SHT_NOBITS,
79 ELF::SHF_ALLOC | ELF::SHF_TLS |
81 SectionKind::getThreadBSS());
84 getContext().getELFSection(".data.rel", ELF::SHT_PROGBITS,
85 ELF::SHF_ALLOC |ELF::SHF_WRITE,
86 SectionKind::getDataRel());
89 getContext().getELFSection(".data.rel.local", ELF::SHT_PROGBITS,
90 ELF::SHF_ALLOC |ELF::SHF_WRITE,
91 SectionKind::getDataRelLocal());
94 getContext().getELFSection(".data.rel.ro", ELF::SHT_PROGBITS,
95 ELF::SHF_ALLOC |ELF::SHF_WRITE,
96 SectionKind::getReadOnlyWithRel());
98 DataRelROLocalSection =
99 getContext().getELFSection(".data.rel.ro.local", ELF::SHT_PROGBITS,
100 ELF::SHF_ALLOC |ELF::SHF_WRITE,
101 SectionKind::getReadOnlyWithRelLocal());
103 MergeableConst4Section =
104 getContext().getELFSection(".rodata.cst4", ELF::SHT_PROGBITS,
105 ELF::SHF_ALLOC |ELF::SHF_MERGE,
106 SectionKind::getMergeableConst4());
108 MergeableConst8Section =
109 getContext().getELFSection(".rodata.cst8", ELF::SHT_PROGBITS,
110 ELF::SHF_ALLOC |ELF::SHF_MERGE,
111 SectionKind::getMergeableConst8());
113 MergeableConst16Section =
114 getContext().getELFSection(".rodata.cst16", ELF::SHT_PROGBITS,
115 ELF::SHF_ALLOC |ELF::SHF_MERGE,
116 SectionKind::getMergeableConst16());
119 getContext().getELFSection(".ctors", ELF::SHT_PROGBITS,
120 ELF::SHF_ALLOC |ELF::SHF_WRITE,
121 SectionKind::getDataRel());
124 getContext().getELFSection(".dtors", ELF::SHT_PROGBITS,
125 ELF::SHF_ALLOC |ELF::SHF_WRITE,
126 SectionKind::getDataRel());
128 // Exception Handling Sections.
130 // FIXME: We're emitting LSDA info into a readonly section on ELF, even though
131 // it contains relocatable pointers. In PIC mode, this is probably a big
132 // runtime hit for C++ apps. Either the contents of the LSDA need to be
133 // adjusted or this should be a data section.
135 getContext().getELFSection(".gcc_except_table", ELF::SHT_PROGBITS,
137 SectionKind::getReadOnly());
138 // Debug Info Sections.
140 getContext().getELFSection(".debug_abbrev", ELF::SHT_PROGBITS, 0,
141 SectionKind::getMetadata());
143 getContext().getELFSection(".debug_info", ELF::SHT_PROGBITS, 0,
144 SectionKind::getMetadata());
146 getContext().getELFSection(".debug_line", ELF::SHT_PROGBITS, 0,
147 SectionKind::getMetadata());
149 getContext().getELFSection(".debug_frame", ELF::SHT_PROGBITS, 0,
150 SectionKind::getMetadata());
151 DwarfPubNamesSection =
152 getContext().getELFSection(".debug_pubnames", ELF::SHT_PROGBITS, 0,
153 SectionKind::getMetadata());
154 DwarfPubTypesSection =
155 getContext().getELFSection(".debug_pubtypes", ELF::SHT_PROGBITS, 0,
156 SectionKind::getMetadata());
158 getContext().getELFSection(".debug_str", ELF::SHT_PROGBITS, 0,
159 SectionKind::getMetadata());
161 getContext().getELFSection(".debug_loc", ELF::SHT_PROGBITS, 0,
162 SectionKind::getMetadata());
163 DwarfARangesSection =
164 getContext().getELFSection(".debug_aranges", ELF::SHT_PROGBITS, 0,
165 SectionKind::getMetadata());
167 getContext().getELFSection(".debug_ranges", ELF::SHT_PROGBITS, 0,
168 SectionKind::getMetadata());
169 DwarfMacroInfoSection =
170 getContext().getELFSection(".debug_macinfo", ELF::SHT_PROGBITS, 0,
171 SectionKind::getMetadata());
174 const MCSection *TargetLoweringObjectFileELF::getEHFrameSection() const {
175 return getContext().getELFSection(".eh_frame", ELF::SHT_PROGBITS,
177 SectionKind::getDataRel());
181 TargetLoweringObjectFileELF::getPersonalityPICSymbol(StringRef Name) const {
182 Twine FullName = StringRef("DW.ref.") + Name;
183 return getContext().GetOrCreateSymbol(FullName);
186 void TargetLoweringObjectFileELF::emitPersonalityValue(MCStreamer &Streamer,
187 const TargetMachine &TM,
188 const MCSymbol *Sym) const {
189 MCSymbol *Label = getPersonalityPICSymbol(Sym->getName());
190 Streamer.EmitSymbolAttribute(Label, MCSA_Hidden);
191 Streamer.EmitSymbolAttribute(Label, MCSA_Weak);
192 Twine SectionName = StringRef(".data.") + Label->getName();
193 SmallString<64> NameData;
194 SectionName.toVector(NameData);
195 unsigned Flags = ELF::SHF_ALLOC | ELF::SHF_WRITE | ELF::SHF_GROUP;
196 const MCSection *Sec = getContext().getELFSection(NameData,
199 SectionKind::getDataRel(),
200 0, Label->getName());
201 Streamer.SwitchSection(Sec);
202 Streamer.EmitValueToAlignment(8);
203 Streamer.EmitSymbolAttribute(Label, MCSA_ELF_TypeObject);
204 const MCExpr *E = MCConstantExpr::Create(8, getContext());
205 Streamer.EmitELFSize(Label, E);
206 Streamer.EmitLabel(Label);
208 unsigned Size = TM.getTargetData()->getPointerSize();
209 Streamer.EmitSymbolValue(Sym, Size);
213 getELFKindForNamedSection(StringRef Name, SectionKind K) {
214 // FIXME: Why is this here? Codegen is should not be in the business
215 // of figuring section flags. If the user wrote section(".eh_frame"),
216 // we should just pass that to MC which will defer to the assembly
217 // or use its default if producing an object file.
218 if (Name.empty() || Name[0] != '.') return K;
220 // Some lame default implementation based on some magic section names.
221 if (Name == ".bss" ||
222 Name.startswith(".bss.") ||
223 Name.startswith(".gnu.linkonce.b.") ||
224 Name.startswith(".llvm.linkonce.b.") ||
226 Name.startswith(".sbss.") ||
227 Name.startswith(".gnu.linkonce.sb.") ||
228 Name.startswith(".llvm.linkonce.sb."))
229 return SectionKind::getBSS();
231 if (Name == ".tdata" ||
232 Name.startswith(".tdata.") ||
233 Name.startswith(".gnu.linkonce.td.") ||
234 Name.startswith(".llvm.linkonce.td."))
235 return SectionKind::getThreadData();
237 if (Name == ".tbss" ||
238 Name.startswith(".tbss.") ||
239 Name.startswith(".gnu.linkonce.tb.") ||
240 Name.startswith(".llvm.linkonce.tb."))
241 return SectionKind::getThreadBSS();
243 if (Name == ".eh_frame")
244 return SectionKind::getDataRel();
250 static unsigned getELFSectionType(StringRef Name, SectionKind K) {
252 if (Name == ".init_array")
253 return ELF::SHT_INIT_ARRAY;
255 if (Name == ".fini_array")
256 return ELF::SHT_FINI_ARRAY;
258 if (Name == ".preinit_array")
259 return ELF::SHT_PREINIT_ARRAY;
261 if (K.isBSS() || K.isThreadBSS())
262 return ELF::SHT_NOBITS;
264 return ELF::SHT_PROGBITS;
269 getELFSectionFlags(SectionKind K) {
273 Flags |= ELF::SHF_ALLOC;
276 Flags |= ELF::SHF_EXECINSTR;
279 Flags |= ELF::SHF_WRITE;
281 if (K.isThreadLocal())
282 Flags |= ELF::SHF_TLS;
284 // K.isMergeableConst() is left out to honour PR4650
285 if (K.isMergeableCString() || K.isMergeableConst4() ||
286 K.isMergeableConst8() || K.isMergeableConst16())
287 Flags |= ELF::SHF_MERGE;
289 if (K.isMergeableCString())
290 Flags |= ELF::SHF_STRINGS;
296 const MCSection *TargetLoweringObjectFileELF::
297 getExplicitSectionGlobal(const GlobalValue *GV, SectionKind Kind,
298 Mangler *Mang, const TargetMachine &TM) const {
299 StringRef SectionName = GV->getSection();
301 // Infer section flags from the section name if we can.
302 Kind = getELFKindForNamedSection(SectionName, Kind);
304 return getContext().getELFSection(SectionName,
305 getELFSectionType(SectionName, Kind),
306 getELFSectionFlags(Kind), Kind);
309 /// getSectionPrefixForGlobal - Return the section prefix name used by options
310 /// FunctionsSections and DataSections.
311 static const char *getSectionPrefixForGlobal(SectionKind Kind) {
312 if (Kind.isText()) return ".text.";
313 if (Kind.isReadOnly()) return ".rodata.";
315 if (Kind.isThreadData()) return ".tdata.";
316 if (Kind.isThreadBSS()) return ".tbss.";
318 if (Kind.isDataNoRel()) return ".data.";
319 if (Kind.isDataRelLocal()) return ".data.rel.local.";
320 if (Kind.isDataRel()) return ".data.rel.";
321 if (Kind.isReadOnlyWithRelLocal()) return ".data.rel.ro.local.";
323 assert(Kind.isReadOnlyWithRel() && "Unknown section kind");
324 return ".data.rel.ro.";
328 const MCSection *TargetLoweringObjectFileELF::
329 SelectSectionForGlobal(const GlobalValue *GV, SectionKind Kind,
330 Mangler *Mang, const TargetMachine &TM) const {
331 // If we have -ffunction-section or -fdata-section then we should emit the
332 // global value to a uniqued section specifically for it.
333 bool EmitUniquedSection;
335 EmitUniquedSection = TM.getFunctionSections();
337 EmitUniquedSection = TM.getDataSections();
339 // If this global is linkonce/weak and the target handles this by emitting it
340 // into a 'uniqued' section name, create and return the section now.
341 if ((GV->isWeakForLinker() || EmitUniquedSection) &&
342 !Kind.isCommon() && !Kind.isBSS()) {
344 Prefix = getSectionPrefixForGlobal(Kind);
346 SmallString<128> Name(Prefix, Prefix+strlen(Prefix));
347 MCSymbol *Sym = Mang->getSymbol(GV);
348 Name.append(Sym->getName().begin(), Sym->getName().end());
349 StringRef Group = "";
350 unsigned Flags = getELFSectionFlags(Kind);
351 if (GV->isWeakForLinker()) {
352 Group = Sym->getName();
353 Flags |= ELF::SHF_GROUP;
356 return getContext().getELFSection(Name.str(),
357 getELFSectionType(Name.str(), Kind),
358 Flags, Kind, 0, Group);
361 if (Kind.isText()) return TextSection;
363 if (Kind.isMergeable1ByteCString() ||
364 Kind.isMergeable2ByteCString() ||
365 Kind.isMergeable4ByteCString()) {
367 // We also need alignment here.
368 // FIXME: this is getting the alignment of the character, not the
369 // alignment of the global!
371 TM.getTargetData()->getPreferredAlignment(cast<GlobalVariable>(GV));
373 const char *SizeSpec = ".rodata.str1.";
374 if (Kind.isMergeable2ByteCString())
375 SizeSpec = ".rodata.str2.";
376 else if (Kind.isMergeable4ByteCString())
377 SizeSpec = ".rodata.str4.";
379 assert(Kind.isMergeable1ByteCString() && "unknown string width");
382 std::string Name = SizeSpec + utostr(Align);
383 return getContext().getELFSection(Name, ELF::SHT_PROGBITS,
390 if (Kind.isMergeableConst()) {
391 if (Kind.isMergeableConst4() && MergeableConst4Section)
392 return MergeableConst4Section;
393 if (Kind.isMergeableConst8() && MergeableConst8Section)
394 return MergeableConst8Section;
395 if (Kind.isMergeableConst16() && MergeableConst16Section)
396 return MergeableConst16Section;
397 return ReadOnlySection; // .const
400 if (Kind.isReadOnly()) return ReadOnlySection;
402 if (Kind.isThreadData()) return TLSDataSection;
403 if (Kind.isThreadBSS()) return TLSBSSSection;
405 // Note: we claim that common symbols are put in BSSSection, but they are
406 // really emitted with the magic .comm directive, which creates a symbol table
407 // entry but not a section.
408 if (Kind.isBSS() || Kind.isCommon()) return BSSSection;
410 if (Kind.isDataNoRel()) return DataSection;
411 if (Kind.isDataRelLocal()) return DataRelLocalSection;
412 if (Kind.isDataRel()) return DataRelSection;
413 if (Kind.isReadOnlyWithRelLocal()) return DataRelROLocalSection;
415 assert(Kind.isReadOnlyWithRel() && "Unknown section kind");
416 return DataRelROSection;
419 /// getSectionForConstant - Given a mergeable constant with the
420 /// specified size and relocation information, return a section that it
421 /// should be placed in.
422 const MCSection *TargetLoweringObjectFileELF::
423 getSectionForConstant(SectionKind Kind) const {
424 if (Kind.isMergeableConst4() && MergeableConst4Section)
425 return MergeableConst4Section;
426 if (Kind.isMergeableConst8() && MergeableConst8Section)
427 return MergeableConst8Section;
428 if (Kind.isMergeableConst16() && MergeableConst16Section)
429 return MergeableConst16Section;
430 if (Kind.isReadOnly())
431 return ReadOnlySection;
433 if (Kind.isReadOnlyWithRelLocal()) return DataRelROLocalSection;
434 assert(Kind.isReadOnlyWithRel() && "Unknown section kind");
435 return DataRelROSection;
438 const MCExpr *TargetLoweringObjectFileELF::
439 getExprForDwarfGlobalReference(const GlobalValue *GV, Mangler *Mang,
440 MachineModuleInfo *MMI,
441 unsigned Encoding, MCStreamer &Streamer) const {
443 if (Encoding & dwarf::DW_EH_PE_indirect) {
444 MachineModuleInfoELF &ELFMMI = MMI->getObjFileInfo<MachineModuleInfoELF>();
446 SmallString<128> Name;
447 Mang->getNameWithPrefix(Name, GV, true);
450 // Add information about the stub reference to ELFMMI so that the stub
451 // gets emitted by the asmprinter.
452 MCSymbol *SSym = getContext().GetOrCreateSymbol(Name.str());
453 MachineModuleInfoImpl::StubValueTy &StubSym = ELFMMI.getGVStubEntry(SSym);
454 if (StubSym.getPointer() == 0) {
455 MCSymbol *Sym = Mang->getSymbol(GV);
456 StubSym = MachineModuleInfoImpl::StubValueTy(Sym, !GV->hasLocalLinkage());
459 return TargetLoweringObjectFile::
460 getExprForDwarfReference(SSym, Encoding & ~dwarf::DW_EH_PE_indirect, Streamer);
463 return TargetLoweringObjectFile::
464 getExprForDwarfGlobalReference(GV, Mang, MMI, Encoding, Streamer);
467 //===----------------------------------------------------------------------===//
469 //===----------------------------------------------------------------------===//
471 void TargetLoweringObjectFileMachO::Initialize(MCContext &Ctx,
472 const TargetMachine &TM) {
473 // _foo.eh symbols are currently always exported so that the linker knows
474 // about them. This is not necessary on 10.6 and later, but it
475 // doesn't hurt anything.
476 // FIXME: I need to get this from Triple.
477 IsFunctionEHSymbolGlobal = true;
478 IsFunctionEHFrameSymbolPrivate = false;
479 SupportsWeakOmittedEHFrame = false;
481 // .comm doesn't support alignment before Leopard.
482 Triple T(((LLVMTargetMachine&)TM).getTargetTriple());
483 if (T.isMacOSX() && T.isMacOSXVersionLT(10, 5))
484 CommDirectiveSupportsAlignment = false;
486 TargetLoweringObjectFile::Initialize(Ctx, TM);
489 = getContext().getMachOSection("__TEXT", "__text",
490 MCSectionMachO::S_ATTR_PURE_INSTRUCTIONS,
491 SectionKind::getText());
493 = getContext().getMachOSection("__DATA", "__data", 0,
494 SectionKind::getDataRel());
496 TLSDataSection // .tdata
497 = getContext().getMachOSection("__DATA", "__thread_data",
498 MCSectionMachO::S_THREAD_LOCAL_REGULAR,
499 SectionKind::getDataRel());
500 TLSBSSSection // .tbss
501 = getContext().getMachOSection("__DATA", "__thread_bss",
502 MCSectionMachO::S_THREAD_LOCAL_ZEROFILL,
503 SectionKind::getThreadBSS());
505 // TODO: Verify datarel below.
506 TLSTLVSection // .tlv
507 = getContext().getMachOSection("__DATA", "__thread_vars",
508 MCSectionMachO::S_THREAD_LOCAL_VARIABLES,
509 SectionKind::getDataRel());
512 = getContext().getMachOSection("__DATA", "__thread_init",
513 MCSectionMachO::S_THREAD_LOCAL_INIT_FUNCTION_POINTERS,
514 SectionKind::getDataRel());
516 CStringSection // .cstring
517 = getContext().getMachOSection("__TEXT", "__cstring",
518 MCSectionMachO::S_CSTRING_LITERALS,
519 SectionKind::getMergeable1ByteCString());
521 = getContext().getMachOSection("__TEXT","__ustring", 0,
522 SectionKind::getMergeable2ByteCString());
523 FourByteConstantSection // .literal4
524 = getContext().getMachOSection("__TEXT", "__literal4",
525 MCSectionMachO::S_4BYTE_LITERALS,
526 SectionKind::getMergeableConst4());
527 EightByteConstantSection // .literal8
528 = getContext().getMachOSection("__TEXT", "__literal8",
529 MCSectionMachO::S_8BYTE_LITERALS,
530 SectionKind::getMergeableConst8());
532 // ld_classic doesn't support .literal16 in 32-bit mode, and ld64 falls back
533 // to using it in -static mode.
534 SixteenByteConstantSection = 0;
535 if (TM.getRelocationModel() != Reloc::Static &&
536 TM.getTargetData()->getPointerSize() == 32)
537 SixteenByteConstantSection = // .literal16
538 getContext().getMachOSection("__TEXT", "__literal16",
539 MCSectionMachO::S_16BYTE_LITERALS,
540 SectionKind::getMergeableConst16());
542 ReadOnlySection // .const
543 = getContext().getMachOSection("__TEXT", "__const", 0,
544 SectionKind::getReadOnly());
547 = getContext().getMachOSection("__TEXT", "__textcoal_nt",
548 MCSectionMachO::S_COALESCED |
549 MCSectionMachO::S_ATTR_PURE_INSTRUCTIONS,
550 SectionKind::getText());
552 = getContext().getMachOSection("__TEXT", "__const_coal",
553 MCSectionMachO::S_COALESCED,
554 SectionKind::getReadOnly());
555 ConstDataSection // .const_data
556 = getContext().getMachOSection("__DATA", "__const", 0,
557 SectionKind::getReadOnlyWithRel());
559 = getContext().getMachOSection("__DATA","__datacoal_nt",
560 MCSectionMachO::S_COALESCED,
561 SectionKind::getDataRel());
563 = getContext().getMachOSection("__DATA","__common",
564 MCSectionMachO::S_ZEROFILL,
565 SectionKind::getBSS());
567 = getContext().getMachOSection("__DATA","__bss", MCSectionMachO::S_ZEROFILL,
568 SectionKind::getBSS());
571 LazySymbolPointerSection
572 = getContext().getMachOSection("__DATA", "__la_symbol_ptr",
573 MCSectionMachO::S_LAZY_SYMBOL_POINTERS,
574 SectionKind::getMetadata());
575 NonLazySymbolPointerSection
576 = getContext().getMachOSection("__DATA", "__nl_symbol_ptr",
577 MCSectionMachO::S_NON_LAZY_SYMBOL_POINTERS,
578 SectionKind::getMetadata());
580 if (TM.getRelocationModel() == Reloc::Static) {
582 = getContext().getMachOSection("__TEXT", "__constructor", 0,
583 SectionKind::getDataRel());
585 = getContext().getMachOSection("__TEXT", "__destructor", 0,
586 SectionKind::getDataRel());
589 = getContext().getMachOSection("__DATA", "__mod_init_func",
590 MCSectionMachO::S_MOD_INIT_FUNC_POINTERS,
591 SectionKind::getDataRel());
593 = getContext().getMachOSection("__DATA", "__mod_term_func",
594 MCSectionMachO::S_MOD_TERM_FUNC_POINTERS,
595 SectionKind::getDataRel());
598 // Exception Handling.
599 LSDASection = getContext().getMachOSection("__TEXT", "__gcc_except_tab", 0,
600 SectionKind::getReadOnlyWithRel());
601 // Debug Information.
603 getContext().getMachOSection("__DWARF", "__debug_abbrev",
604 MCSectionMachO::S_ATTR_DEBUG,
605 SectionKind::getMetadata());
607 getContext().getMachOSection("__DWARF", "__debug_info",
608 MCSectionMachO::S_ATTR_DEBUG,
609 SectionKind::getMetadata());
611 getContext().getMachOSection("__DWARF", "__debug_line",
612 MCSectionMachO::S_ATTR_DEBUG,
613 SectionKind::getMetadata());
615 getContext().getMachOSection("__DWARF", "__debug_frame",
616 MCSectionMachO::S_ATTR_DEBUG,
617 SectionKind::getMetadata());
618 DwarfPubNamesSection =
619 getContext().getMachOSection("__DWARF", "__debug_pubnames",
620 MCSectionMachO::S_ATTR_DEBUG,
621 SectionKind::getMetadata());
622 DwarfPubTypesSection =
623 getContext().getMachOSection("__DWARF", "__debug_pubtypes",
624 MCSectionMachO::S_ATTR_DEBUG,
625 SectionKind::getMetadata());
627 getContext().getMachOSection("__DWARF", "__debug_str",
628 MCSectionMachO::S_ATTR_DEBUG,
629 SectionKind::getMetadata());
631 getContext().getMachOSection("__DWARF", "__debug_loc",
632 MCSectionMachO::S_ATTR_DEBUG,
633 SectionKind::getMetadata());
634 DwarfARangesSection =
635 getContext().getMachOSection("__DWARF", "__debug_aranges",
636 MCSectionMachO::S_ATTR_DEBUG,
637 SectionKind::getMetadata());
639 getContext().getMachOSection("__DWARF", "__debug_ranges",
640 MCSectionMachO::S_ATTR_DEBUG,
641 SectionKind::getMetadata());
642 DwarfMacroInfoSection =
643 getContext().getMachOSection("__DWARF", "__debug_macinfo",
644 MCSectionMachO::S_ATTR_DEBUG,
645 SectionKind::getMetadata());
646 DwarfDebugInlineSection =
647 getContext().getMachOSection("__DWARF", "__debug_inlined",
648 MCSectionMachO::S_ATTR_DEBUG,
649 SectionKind::getMetadata());
651 TLSExtraDataSection = TLSTLVSection;
654 const MCSection *TargetLoweringObjectFileMachO::getEHFrameSection() const {
655 return getContext().getMachOSection("__TEXT", "__eh_frame",
656 MCSectionMachO::S_COALESCED |
657 MCSectionMachO::S_ATTR_NO_TOC |
658 MCSectionMachO::S_ATTR_STRIP_STATIC_SYMS |
659 MCSectionMachO::S_ATTR_LIVE_SUPPORT,
660 SectionKind::getReadOnly());
663 const MCSection *TargetLoweringObjectFileMachO::
664 getExplicitSectionGlobal(const GlobalValue *GV, SectionKind Kind,
665 Mangler *Mang, const TargetMachine &TM) const {
666 // Parse the section specifier and create it if valid.
667 StringRef Segment, Section;
668 unsigned TAA = 0, StubSize = 0;
670 std::string ErrorCode =
671 MCSectionMachO::ParseSectionSpecifier(GV->getSection(), Segment, Section,
672 TAA, TAAParsed, StubSize);
673 if (!ErrorCode.empty()) {
674 // If invalid, report the error with report_fatal_error.
675 report_fatal_error("Global variable '" + GV->getNameStr() +
676 "' has an invalid section specifier '" + GV->getSection()+
677 "': " + ErrorCode + ".");
678 // Fall back to dropping it into the data section.
683 const MCSectionMachO *S =
684 getContext().getMachOSection(Segment, Section, TAA, StubSize, Kind);
686 // If TAA wasn't set by ParseSectionSpecifier() above,
687 // use the value returned by getMachOSection() as a default.
689 TAA = S->getTypeAndAttributes();
691 // Okay, now that we got the section, verify that the TAA & StubSize agree.
692 // If the user declared multiple globals with different section flags, we need
693 // to reject it here.
694 if (S->getTypeAndAttributes() != TAA || S->getStubSize() != StubSize) {
695 // If invalid, report the error with report_fatal_error.
696 report_fatal_error("Global variable '" + GV->getNameStr() +
697 "' section type or attributes does not match previous"
698 " section specifier");
704 const MCSection *TargetLoweringObjectFileMachO::
705 SelectSectionForGlobal(const GlobalValue *GV, SectionKind Kind,
706 Mangler *Mang, const TargetMachine &TM) const {
708 // Handle thread local data.
709 if (Kind.isThreadBSS()) return TLSBSSSection;
710 if (Kind.isThreadData()) return TLSDataSection;
713 return GV->isWeakForLinker() ? TextCoalSection : TextSection;
715 // If this is weak/linkonce, put this in a coalescable section, either in text
716 // or data depending on if it is writable.
717 if (GV->isWeakForLinker()) {
718 if (Kind.isReadOnly())
719 return ConstTextCoalSection;
720 return DataCoalSection;
723 // FIXME: Alignment check should be handled by section classifier.
724 if (Kind.isMergeable1ByteCString() &&
725 TM.getTargetData()->getPreferredAlignment(cast<GlobalVariable>(GV)) < 32)
726 return CStringSection;
728 // Do not put 16-bit arrays in the UString section if they have an
729 // externally visible label, this runs into issues with certain linker
731 if (Kind.isMergeable2ByteCString() && !GV->hasExternalLinkage() &&
732 TM.getTargetData()->getPreferredAlignment(cast<GlobalVariable>(GV)) < 32)
733 return UStringSection;
735 if (Kind.isMergeableConst()) {
736 if (Kind.isMergeableConst4())
737 return FourByteConstantSection;
738 if (Kind.isMergeableConst8())
739 return EightByteConstantSection;
740 if (Kind.isMergeableConst16() && SixteenByteConstantSection)
741 return SixteenByteConstantSection;
744 // Otherwise, if it is readonly, but not something we can specially optimize,
745 // just drop it in .const.
746 if (Kind.isReadOnly())
747 return ReadOnlySection;
749 // If this is marked const, put it into a const section. But if the dynamic
750 // linker needs to write to it, put it in the data segment.
751 if (Kind.isReadOnlyWithRel())
752 return ConstDataSection;
754 // Put zero initialized globals with strong external linkage in the
755 // DATA, __common section with the .zerofill directive.
756 if (Kind.isBSSExtern())
757 return DataCommonSection;
759 // Put zero initialized globals with local linkage in __DATA,__bss directive
760 // with the .zerofill directive (aka .lcomm).
761 if (Kind.isBSSLocal())
762 return DataBSSSection;
764 // Otherwise, just drop the variable in the normal data section.
769 TargetLoweringObjectFileMachO::getSectionForConstant(SectionKind Kind) const {
770 // If this constant requires a relocation, we have to put it in the data
771 // segment, not in the text segment.
772 if (Kind.isDataRel() || Kind.isReadOnlyWithRel())
773 return ConstDataSection;
775 if (Kind.isMergeableConst4())
776 return FourByteConstantSection;
777 if (Kind.isMergeableConst8())
778 return EightByteConstantSection;
779 if (Kind.isMergeableConst16() && SixteenByteConstantSection)
780 return SixteenByteConstantSection;
781 return ReadOnlySection; // .const
784 /// shouldEmitUsedDirectiveFor - This hook allows targets to selectively decide
785 /// not to emit the UsedDirective for some symbols in llvm.used.
786 // FIXME: REMOVE this (rdar://7071300)
787 bool TargetLoweringObjectFileMachO::
788 shouldEmitUsedDirectiveFor(const GlobalValue *GV, Mangler *Mang) const {
789 /// On Darwin, internally linked data beginning with "L" or "l" does not have
790 /// the directive emitted (this occurs in ObjC metadata).
791 if (!GV) return false;
793 // Check whether the mangled name has the "Private" or "LinkerPrivate" prefix.
794 if (GV->hasLocalLinkage() && !isa<Function>(GV)) {
795 // FIXME: ObjC metadata is currently emitted as internal symbols that have
796 // \1L and \0l prefixes on them. Fix them to be Private/LinkerPrivate and
797 // this horrible hack can go away.
798 MCSymbol *Sym = Mang->getSymbol(GV);
799 if (Sym->getName()[0] == 'L' || Sym->getName()[0] == 'l')
806 const MCExpr *TargetLoweringObjectFileMachO::
807 getExprForDwarfGlobalReference(const GlobalValue *GV, Mangler *Mang,
808 MachineModuleInfo *MMI, unsigned Encoding,
809 MCStreamer &Streamer) const {
810 // The mach-o version of this method defaults to returning a stub reference.
812 if (Encoding & DW_EH_PE_indirect) {
813 MachineModuleInfoMachO &MachOMMI =
814 MMI->getObjFileInfo<MachineModuleInfoMachO>();
816 SmallString<128> Name;
817 Mang->getNameWithPrefix(Name, GV, true);
818 Name += "$non_lazy_ptr";
820 // Add information about the stub reference to MachOMMI so that the stub
821 // gets emitted by the asmprinter.
822 MCSymbol *SSym = getContext().GetOrCreateSymbol(Name.str());
823 MachineModuleInfoImpl::StubValueTy &StubSym = MachOMMI.getGVStubEntry(SSym);
824 if (StubSym.getPointer() == 0) {
825 MCSymbol *Sym = Mang->getSymbol(GV);
826 StubSym = MachineModuleInfoImpl::StubValueTy(Sym, !GV->hasLocalLinkage());
829 return TargetLoweringObjectFile::
830 getExprForDwarfReference(SSym, Encoding & ~dwarf::DW_EH_PE_indirect, Streamer);
833 return TargetLoweringObjectFile::
834 getExprForDwarfGlobalReference(GV, Mang, MMI, Encoding, Streamer);
837 unsigned TargetLoweringObjectFileMachO::getPersonalityEncoding() const {
838 return DW_EH_PE_indirect | DW_EH_PE_pcrel | DW_EH_PE_sdata4;
841 unsigned TargetLoweringObjectFileMachO::getLSDAEncoding() const {
842 return DW_EH_PE_pcrel;
845 unsigned TargetLoweringObjectFileMachO::getFDEEncoding() const {
846 return DW_EH_PE_pcrel;
849 unsigned TargetLoweringObjectFileMachO::getTTypeEncoding() const {
850 return DW_EH_PE_indirect | DW_EH_PE_pcrel | DW_EH_PE_sdata4;
853 //===----------------------------------------------------------------------===//
855 //===----------------------------------------------------------------------===//
857 void TargetLoweringObjectFileCOFF::Initialize(MCContext &Ctx,
858 const TargetMachine &TM) {
859 TargetLoweringObjectFile::Initialize(Ctx, TM);
861 getContext().getCOFFSection(".text",
862 COFF::IMAGE_SCN_CNT_CODE |
863 COFF::IMAGE_SCN_MEM_EXECUTE |
864 COFF::IMAGE_SCN_MEM_READ,
865 SectionKind::getText());
867 getContext().getCOFFSection(".data",
868 COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
869 COFF::IMAGE_SCN_MEM_READ |
870 COFF::IMAGE_SCN_MEM_WRITE,
871 SectionKind::getDataRel());
873 getContext().getCOFFSection(".rdata",
874 COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
875 COFF::IMAGE_SCN_MEM_READ,
876 SectionKind::getReadOnly());
878 getContext().getCOFFSection(".ctors",
879 COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
880 COFF::IMAGE_SCN_MEM_READ |
881 COFF::IMAGE_SCN_MEM_WRITE,
882 SectionKind::getDataRel());
884 getContext().getCOFFSection(".dtors",
885 COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
886 COFF::IMAGE_SCN_MEM_READ |
887 COFF::IMAGE_SCN_MEM_WRITE,
888 SectionKind::getDataRel());
890 // FIXME: We're emitting LSDA info into a readonly section on COFF, even
891 // though it contains relocatable pointers. In PIC mode, this is probably a
892 // big runtime hit for C++ apps. Either the contents of the LSDA need to be
893 // adjusted or this should be a data section.
895 getContext().getCOFFSection(".gcc_except_table",
896 COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
897 COFF::IMAGE_SCN_MEM_READ,
898 SectionKind::getReadOnly());
901 getContext().getCOFFSection(".debug_abbrev",
902 COFF::IMAGE_SCN_MEM_DISCARDABLE |
903 COFF::IMAGE_SCN_MEM_READ,
904 SectionKind::getMetadata());
906 getContext().getCOFFSection(".debug_info",
907 COFF::IMAGE_SCN_MEM_DISCARDABLE |
908 COFF::IMAGE_SCN_MEM_READ,
909 SectionKind::getMetadata());
911 getContext().getCOFFSection(".debug_line",
912 COFF::IMAGE_SCN_MEM_DISCARDABLE |
913 COFF::IMAGE_SCN_MEM_READ,
914 SectionKind::getMetadata());
916 getContext().getCOFFSection(".debug_frame",
917 COFF::IMAGE_SCN_MEM_DISCARDABLE |
918 COFF::IMAGE_SCN_MEM_READ,
919 SectionKind::getMetadata());
920 DwarfPubNamesSection =
921 getContext().getCOFFSection(".debug_pubnames",
922 COFF::IMAGE_SCN_MEM_DISCARDABLE |
923 COFF::IMAGE_SCN_MEM_READ,
924 SectionKind::getMetadata());
925 DwarfPubTypesSection =
926 getContext().getCOFFSection(".debug_pubtypes",
927 COFF::IMAGE_SCN_MEM_DISCARDABLE |
928 COFF::IMAGE_SCN_MEM_READ,
929 SectionKind::getMetadata());
931 getContext().getCOFFSection(".debug_str",
932 COFF::IMAGE_SCN_MEM_DISCARDABLE |
933 COFF::IMAGE_SCN_MEM_READ,
934 SectionKind::getMetadata());
936 getContext().getCOFFSection(".debug_loc",
937 COFF::IMAGE_SCN_MEM_DISCARDABLE |
938 COFF::IMAGE_SCN_MEM_READ,
939 SectionKind::getMetadata());
940 DwarfARangesSection =
941 getContext().getCOFFSection(".debug_aranges",
942 COFF::IMAGE_SCN_MEM_DISCARDABLE |
943 COFF::IMAGE_SCN_MEM_READ,
944 SectionKind::getMetadata());
946 getContext().getCOFFSection(".debug_ranges",
947 COFF::IMAGE_SCN_MEM_DISCARDABLE |
948 COFF::IMAGE_SCN_MEM_READ,
949 SectionKind::getMetadata());
950 DwarfMacroInfoSection =
951 getContext().getCOFFSection(".debug_macinfo",
952 COFF::IMAGE_SCN_MEM_DISCARDABLE |
953 COFF::IMAGE_SCN_MEM_READ,
954 SectionKind::getMetadata());
957 getContext().getCOFFSection(".drectve",
958 COFF::IMAGE_SCN_LNK_INFO,
959 SectionKind::getMetadata());
962 const MCSection *TargetLoweringObjectFileCOFF::getEHFrameSection() const {
963 return getContext().getCOFFSection(".eh_frame",
964 COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
965 COFF::IMAGE_SCN_MEM_READ |
966 COFF::IMAGE_SCN_MEM_WRITE,
967 SectionKind::getDataRel());
972 getCOFFSectionFlags(SectionKind K) {
977 COFF::IMAGE_SCN_MEM_DISCARDABLE;
980 COFF::IMAGE_SCN_MEM_EXECUTE |
981 COFF::IMAGE_SCN_MEM_READ |
982 COFF::IMAGE_SCN_CNT_CODE;
985 COFF::IMAGE_SCN_CNT_UNINITIALIZED_DATA |
986 COFF::IMAGE_SCN_MEM_READ |
987 COFF::IMAGE_SCN_MEM_WRITE;
988 else if (K.isReadOnly())
990 COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
991 COFF::IMAGE_SCN_MEM_READ;
992 else if (K.isWriteable())
994 COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
995 COFF::IMAGE_SCN_MEM_READ |
996 COFF::IMAGE_SCN_MEM_WRITE;
1001 const MCSection *TargetLoweringObjectFileCOFF::
1002 getExplicitSectionGlobal(const GlobalValue *GV, SectionKind Kind,
1003 Mangler *Mang, const TargetMachine &TM) const {
1004 return getContext().getCOFFSection(GV->getSection(),
1005 getCOFFSectionFlags(Kind),
1009 static const char *getCOFFSectionPrefixForUniqueGlobal(SectionKind Kind) {
1014 if (Kind.isWriteable())
1020 const MCSection *TargetLoweringObjectFileCOFF::
1021 SelectSectionForGlobal(const GlobalValue *GV, SectionKind Kind,
1022 Mangler *Mang, const TargetMachine &TM) const {
1023 assert(!Kind.isThreadLocal() && "Doesn't support TLS");
1025 // If this global is linkonce/weak and the target handles this by emitting it
1026 // into a 'uniqued' section name, create and return the section now.
1027 if (GV->isWeakForLinker()) {
1028 const char *Prefix = getCOFFSectionPrefixForUniqueGlobal(Kind);
1029 SmallString<128> Name(Prefix, Prefix+strlen(Prefix));
1030 MCSymbol *Sym = Mang->getSymbol(GV);
1031 Name.append(Sym->getName().begin() + 1, Sym->getName().end());
1033 unsigned Characteristics = getCOFFSectionFlags(Kind);
1035 Characteristics |= COFF::IMAGE_SCN_LNK_COMDAT;
1037 return getContext().getCOFFSection(Name.str(), Characteristics,
1038 COFF::IMAGE_COMDAT_SELECT_ANY, Kind);
1042 return getTextSection();
1044 return getDataSection();