1 //===-- llvm/Target/TargetLoweringObjectFile.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/Target/TargetLoweringObjectFile.h"
16 #include "llvm/Constants.h"
17 #include "llvm/DerivedTypes.h"
18 #include "llvm/Function.h"
19 #include "llvm/GlobalVariable.h"
20 #include "llvm/MC/MCContext.h"
21 #include "llvm/MC/MCSectionMachO.h"
22 #include "llvm/Target/TargetAsmInfo.h"
23 #include "llvm/Target/TargetData.h"
24 #include "llvm/Target/TargetMachine.h"
25 #include "llvm/Target/TargetOptions.h"
26 #include "llvm/Support/Mangler.h"
27 #include "llvm/ADT/SmallString.h"
28 #include "llvm/ADT/StringExtras.h"
31 //===----------------------------------------------------------------------===//
33 //===----------------------------------------------------------------------===//
35 TargetLoweringObjectFile::TargetLoweringObjectFile() : Ctx(0) {
40 StaticCtorSection = 0;
41 StaticDtorSection = 0;
45 DwarfAbbrevSection = 0;
48 DwarfFrameSection = 0;
49 DwarfPubNamesSection = 0;
50 DwarfPubTypesSection = 0;
51 DwarfDebugInlineSection = 0;
54 DwarfARangesSection = 0;
55 DwarfRangesSection = 0;
56 DwarfMacroInfoSection = 0;
59 TargetLoweringObjectFile::~TargetLoweringObjectFile() {
62 static bool isSuitableForBSS(const GlobalVariable *GV) {
63 Constant *C = GV->getInitializer();
65 // Must have zero initializer.
66 if (!C->isNullValue())
69 // Leave constant zeros in readonly constant sections, so they can be shared.
73 // If the global has an explicit section specified, don't put it in BSS.
74 if (!GV->getSection().empty())
77 // If -nozero-initialized-in-bss is specified, don't ever use BSS.
81 // Otherwise, put it in BSS!
85 /// IsNullTerminatedString - Return true if the specified constant (which is
86 /// known to have a type that is an array of 1/2/4 byte elements) ends with a
87 /// nul value and contains no other nuls in it.
88 static bool IsNullTerminatedString(const Constant *C) {
89 const ArrayType *ATy = cast<ArrayType>(C->getType());
91 // First check: is we have constant array of i8 terminated with zero
92 if (const ConstantArray *CVA = dyn_cast<ConstantArray>(C)) {
93 if (ATy->getNumElements() == 0) return false;
96 dyn_cast<ConstantInt>(CVA->getOperand(ATy->getNumElements()-1));
97 if (Null == 0 || Null->getZExtValue() != 0)
98 return false; // Not null terminated.
100 // Verify that the null doesn't occur anywhere else in the string.
101 for (unsigned i = 0, e = ATy->getNumElements()-1; i != e; ++i)
102 // Reject constantexpr elements etc.
103 if (!isa<ConstantInt>(CVA->getOperand(i)) ||
104 CVA->getOperand(i) == Null)
109 // Another possibility: [1 x i8] zeroinitializer
110 if (isa<ConstantAggregateZero>(C))
111 return ATy->getNumElements() == 1;
116 /// getKindForGlobal - This is a top-level target-independent classifier for
117 /// a global variable. Given an global variable and information from TM, it
118 /// classifies the global in a variety of ways that make various target
119 /// implementations simpler. The target implementation is free to ignore this
120 /// extra info of course.
121 SectionKind TargetLoweringObjectFile::getKindForGlobal(const GlobalValue *GV,
122 const TargetMachine &TM){
123 assert(!GV->isDeclaration() && !GV->hasAvailableExternallyLinkage() &&
124 "Can only be used for global definitions");
126 Reloc::Model ReloModel = TM.getRelocationModel();
128 // Early exit - functions should be always in text sections.
129 const GlobalVariable *GVar = dyn_cast<GlobalVariable>(GV);
131 return SectionKind::getText();
133 // Handle thread-local data first.
134 if (GVar->isThreadLocal()) {
135 if (isSuitableForBSS(GVar))
136 return SectionKind::getThreadBSS();
137 return SectionKind::getThreadData();
140 // Variable can be easily put to BSS section.
141 if (isSuitableForBSS(GVar))
142 return SectionKind::getBSS();
144 Constant *C = GVar->getInitializer();
146 // If the global is marked constant, we can put it into a mergable section,
147 // a mergable string section, or general .data if it contains relocations.
148 if (GVar->isConstant()) {
149 // If the initializer for the global contains something that requires a
150 // relocation, then we may have to drop this into a wriable data section
151 // even though it is marked const.
152 switch (C->getRelocationInfo()) {
153 default: llvm_unreachable("unknown relocation info kind");
154 case Constant::NoRelocation:
155 // If initializer is a null-terminated string, put it in a "cstring"
156 // section of the right width.
157 if (const ArrayType *ATy = dyn_cast<ArrayType>(C->getType())) {
158 if (const IntegerType *ITy =
159 dyn_cast<IntegerType>(ATy->getElementType())) {
160 if ((ITy->getBitWidth() == 8 || ITy->getBitWidth() == 16 ||
161 ITy->getBitWidth() == 32) &&
162 IsNullTerminatedString(C)) {
163 if (ITy->getBitWidth() == 8)
164 return SectionKind::getMergeable1ByteCString();
165 if (ITy->getBitWidth() == 16)
166 return SectionKind::getMergeable2ByteCString();
168 assert(ITy->getBitWidth() == 32 && "Unknown width");
169 return SectionKind::getMergeable4ByteCString();
174 // Otherwise, just drop it into a mergable constant section. If we have
175 // a section for this size, use it, otherwise use the arbitrary sized
177 switch (TM.getTargetData()->getTypeAllocSize(C->getType())) {
178 case 4: return SectionKind::getMergeableConst4();
179 case 8: return SectionKind::getMergeableConst8();
180 case 16: return SectionKind::getMergeableConst16();
181 default: return SectionKind::getMergeableConst();
184 case Constant::LocalRelocation:
185 // In static relocation model, the linker will resolve all addresses, so
186 // the relocation entries will actually be constants by the time the app
187 // starts up. However, we can't put this into a mergable section, because
188 // the linker doesn't take relocations into consideration when it tries to
189 // merge entries in the section.
190 if (ReloModel == Reloc::Static)
191 return SectionKind::getReadOnly();
193 // Otherwise, the dynamic linker needs to fix it up, put it in the
194 // writable data.rel.local section.
195 return SectionKind::getReadOnlyWithRelLocal();
197 case Constant::GlobalRelocations:
198 // In static relocation model, the linker will resolve all addresses, so
199 // the relocation entries will actually be constants by the time the app
200 // starts up. However, we can't put this into a mergable section, because
201 // the linker doesn't take relocations into consideration when it tries to
202 // merge entries in the section.
203 if (ReloModel == Reloc::Static)
204 return SectionKind::getReadOnly();
206 // Otherwise, the dynamic linker needs to fix it up, put it in the
207 // writable data.rel section.
208 return SectionKind::getReadOnlyWithRel();
212 // Okay, this isn't a constant. If the initializer for the global is going
213 // to require a runtime relocation by the dynamic linker, put it into a more
214 // specific section to improve startup time of the app. This coalesces these
215 // globals together onto fewer pages, improving the locality of the dynamic
217 if (ReloModel == Reloc::Static)
218 return SectionKind::getDataNoRel();
220 switch (C->getRelocationInfo()) {
221 default: llvm_unreachable("unknown relocation info kind");
222 case Constant::NoRelocation:
223 return SectionKind::getDataNoRel();
224 case Constant::LocalRelocation:
225 return SectionKind::getDataRelLocal();
226 case Constant::GlobalRelocations:
227 return SectionKind::getDataRel();
231 /// SectionForGlobal - This method computes the appropriate section to emit
232 /// the specified global variable or function definition. This should not
233 /// be passed external (or available externally) globals.
234 const MCSection *TargetLoweringObjectFile::
235 SectionForGlobal(const GlobalValue *GV, SectionKind Kind, Mangler *Mang,
236 const TargetMachine &TM) const {
237 // Select section name.
238 if (GV->hasSection())
239 return getExplicitSectionGlobal(GV, Kind, Mang, TM);
242 // Use default section depending on the 'type' of global
243 return SelectSectionForGlobal(GV, Kind, Mang, TM);
247 // Lame default implementation. Calculate the section name for global.
249 TargetLoweringObjectFile::SelectSectionForGlobal(const GlobalValue *GV,
252 const TargetMachine &TM) const{
253 assert(!Kind.isThreadLocal() && "Doesn't support TLS");
256 return getTextSection();
258 if (Kind.isBSS() && BSSSection != 0)
261 if (Kind.isReadOnly() && ReadOnlySection != 0)
262 return ReadOnlySection;
264 return getDataSection();
267 /// getSectionForConstant - Given a mergable constant with the
268 /// specified size and relocation information, return a section that it
269 /// should be placed in.
271 TargetLoweringObjectFile::getSectionForConstant(SectionKind Kind) const {
272 if (Kind.isReadOnly() && ReadOnlySection != 0)
273 return ReadOnlySection;
280 //===----------------------------------------------------------------------===//
282 //===----------------------------------------------------------------------===//
284 const MCSection *TargetLoweringObjectFileELF::
285 getELFSection(const char *Name, bool isDirective, SectionKind Kind) const {
286 if (MCSection *S = getContext().GetSection(Name))
288 return MCSectionELF::Create(Name, isDirective, Kind, getContext());
291 void TargetLoweringObjectFileELF::Initialize(MCContext &Ctx,
292 const TargetMachine &TM) {
293 TargetLoweringObjectFile::Initialize(Ctx, TM);
295 BSSSection = getELFSection("\t.bss", true, SectionKind::getBSS());
297 // PPC/Linux doesn't support the .bss directive, it needs .section .bss.
298 // FIXME: Does .section .bss work everywhere??
299 // FIXME2: this should just be handle by the section printer. We should get
300 // away from syntactic view of the sections and MCSection should just be a
302 BSSSection = getELFSection("\t.bss", false, SectionKind::getBSS());
305 TextSection = getELFSection("\t.text", true, SectionKind::getText());
306 DataSection = getELFSection("\t.data", true, SectionKind::getDataRel());
308 getELFSection("\t.rodata", false, SectionKind::getReadOnly());
310 getELFSection("\t.tdata", false, SectionKind::getThreadData());
312 TLSBSSSection = getELFSection("\t.tbss", false,
313 SectionKind::getThreadBSS());
315 DataRelSection = getELFSection("\t.data.rel", false,
316 SectionKind::getDataRel());
317 DataRelLocalSection = getELFSection("\t.data.rel.local", false,
318 SectionKind::getDataRelLocal());
319 DataRelROSection = getELFSection("\t.data.rel.ro", false,
320 SectionKind::getReadOnlyWithRel());
321 DataRelROLocalSection =
322 getELFSection("\t.data.rel.ro.local", false,
323 SectionKind::getReadOnlyWithRelLocal());
325 MergeableConst4Section = getELFSection(".rodata.cst4", false,
326 SectionKind::getMergeableConst4());
327 MergeableConst8Section = getELFSection(".rodata.cst8", false,
328 SectionKind::getMergeableConst8());
329 MergeableConst16Section = getELFSection(".rodata.cst16", false,
330 SectionKind::getMergeableConst16());
333 getELFSection(".ctors", false, SectionKind::getDataRel());
335 getELFSection(".dtors", false, SectionKind::getDataRel());
337 // Exception Handling Sections.
339 // FIXME: We're emitting LSDA info into a readonly section on ELF, even though
340 // it contains relocatable pointers. In PIC mode, this is probably a big
341 // runtime hit for C++ apps. Either the contents of the LSDA need to be
342 // adjusted or this should be a data section.
344 getELFSection(".gcc_except_table", false, SectionKind::getReadOnly());
346 getELFSection(".eh_frame", false, SectionKind::getDataRel());
348 // Debug Info Sections.
350 getELFSection(".debug_abbrev", false, SectionKind::getMetadata());
352 getELFSection(".debug_info", false, SectionKind::getMetadata());
354 getELFSection(".debug_line", false, SectionKind::getMetadata());
356 getELFSection(".debug_frame", false, SectionKind::getMetadata());
357 DwarfPubNamesSection =
358 getELFSection(".debug_pubnames", false, SectionKind::getMetadata());
359 DwarfPubTypesSection =
360 getELFSection(".debug_pubtypes", false, SectionKind::getMetadata());
362 getELFSection(".debug_str", false, SectionKind::getMetadata());
364 getELFSection(".debug_loc", false, SectionKind::getMetadata());
365 DwarfARangesSection =
366 getELFSection(".debug_aranges", false, SectionKind::getMetadata());
368 getELFSection(".debug_ranges", false, SectionKind::getMetadata());
369 DwarfMacroInfoSection =
370 getELFSection(".debug_macinfo", false, SectionKind::getMetadata());
375 getELFKindForNamedSection(const char *Name, SectionKind K) {
376 if (Name[0] != '.') return K;
378 // Some lame default implementation based on some magic section names.
379 if (strncmp(Name, ".gnu.linkonce.b.", 16) == 0 ||
380 strncmp(Name, ".llvm.linkonce.b.", 17) == 0 ||
381 strncmp(Name, ".gnu.linkonce.sb.", 17) == 0 ||
382 strncmp(Name, ".llvm.linkonce.sb.", 18) == 0)
383 return SectionKind::getBSS();
385 if (strcmp(Name, ".tdata") == 0 ||
386 strncmp(Name, ".tdata.", 7) == 0 ||
387 strncmp(Name, ".gnu.linkonce.td.", 17) == 0 ||
388 strncmp(Name, ".llvm.linkonce.td.", 18) == 0)
389 return SectionKind::getThreadData();
391 if (strcmp(Name, ".tbss") == 0 ||
392 strncmp(Name, ".tbss.", 6) == 0 ||
393 strncmp(Name, ".gnu.linkonce.tb.", 17) == 0 ||
394 strncmp(Name, ".llvm.linkonce.tb.", 18) == 0)
395 return SectionKind::getThreadBSS();
400 const MCSection *TargetLoweringObjectFileELF::
401 getExplicitSectionGlobal(const GlobalValue *GV, SectionKind Kind,
402 Mangler *Mang, const TargetMachine &TM) const {
403 // Infer section flags from the section name if we can.
404 Kind = getELFKindForNamedSection(GV->getSection().c_str(), Kind);
406 return getELFSection(GV->getSection().c_str(), false, Kind);
409 static const char *getSectionPrefixForUniqueGlobal(SectionKind Kind) {
410 if (Kind.isText()) return ".gnu.linkonce.t.";
411 if (Kind.isReadOnly()) return ".gnu.linkonce.r.";
413 if (Kind.isThreadData()) return ".gnu.linkonce.td.";
414 if (Kind.isThreadBSS()) return ".gnu.linkonce.tb.";
416 if (Kind.isBSS()) return ".gnu.linkonce.b.";
417 if (Kind.isDataNoRel()) return ".gnu.linkonce.d.";
418 if (Kind.isDataRelLocal()) return ".gnu.linkonce.d.rel.local.";
419 if (Kind.isDataRel()) return ".gnu.linkonce.d.rel.";
420 if (Kind.isReadOnlyWithRelLocal()) return ".gnu.linkonce.d.rel.ro.local.";
422 assert(Kind.isReadOnlyWithRel() && "Unknown section kind");
423 return ".gnu.linkonce.d.rel.ro.";
426 const MCSection *TargetLoweringObjectFileELF::
427 SelectSectionForGlobal(const GlobalValue *GV, SectionKind Kind,
428 Mangler *Mang, const TargetMachine &TM) const {
430 // If this global is linkonce/weak and the target handles this by emitting it
431 // into a 'uniqued' section name, create and return the section now.
432 if (GV->isWeakForLinker()) {
433 const char *Prefix = getSectionPrefixForUniqueGlobal(Kind);
434 std::string Name = Mang->makeNameProper(GV->getNameStr());
435 return getELFSection((Prefix+Name).c_str(), false, Kind);
438 if (Kind.isText()) return TextSection;
440 if (Kind.isMergeable1ByteCString() ||
441 Kind.isMergeable2ByteCString() ||
442 Kind.isMergeable4ByteCString()) {
444 // We also need alignment here.
445 // FIXME: this is getting the alignment of the character, not the
446 // alignment of the global!
448 TM.getTargetData()->getPreferredAlignment(cast<GlobalVariable>(GV));
450 const char *SizeSpec = ".rodata.str1.";
451 if (Kind.isMergeable2ByteCString())
452 SizeSpec = ".rodata.str2.";
453 else if (Kind.isMergeable4ByteCString())
454 SizeSpec = ".rodata.str4.";
456 assert(Kind.isMergeable1ByteCString() && "unknown string width");
459 std::string Name = SizeSpec + utostr(Align);
460 return getELFSection(Name.c_str(), false, Kind);
463 if (Kind.isMergeableConst()) {
464 if (Kind.isMergeableConst4())
465 return MergeableConst4Section;
466 if (Kind.isMergeableConst8())
467 return MergeableConst8Section;
468 if (Kind.isMergeableConst16())
469 return MergeableConst16Section;
470 return ReadOnlySection; // .const
473 if (Kind.isReadOnly()) return ReadOnlySection;
475 if (Kind.isThreadData()) return TLSDataSection;
476 if (Kind.isThreadBSS()) return TLSBSSSection;
478 if (Kind.isBSS()) return BSSSection;
480 if (Kind.isDataNoRel()) return DataSection;
481 if (Kind.isDataRelLocal()) return DataRelLocalSection;
482 if (Kind.isDataRel()) return DataRelSection;
483 if (Kind.isReadOnlyWithRelLocal()) return DataRelROLocalSection;
485 assert(Kind.isReadOnlyWithRel() && "Unknown section kind");
486 return DataRelROSection;
489 /// getSectionForConstant - Given a mergeable constant with the
490 /// specified size and relocation information, return a section that it
491 /// should be placed in.
492 const MCSection *TargetLoweringObjectFileELF::
493 getSectionForConstant(SectionKind Kind) const {
494 if (Kind.isMergeableConst4())
495 return MergeableConst4Section;
496 if (Kind.isMergeableConst8())
497 return MergeableConst8Section;
498 if (Kind.isMergeableConst16())
499 return MergeableConst16Section;
500 if (Kind.isReadOnly())
501 return ReadOnlySection;
503 if (Kind.isReadOnlyWithRelLocal()) return DataRelROLocalSection;
504 assert(Kind.isReadOnlyWithRel() && "Unknown section kind");
505 return DataRelROSection;
508 //===----------------------------------------------------------------------===//
510 //===----------------------------------------------------------------------===//
512 typedef StringMap<const MCSectionMachO*> MachOUniqueMapTy;
514 TargetLoweringObjectFileMachO::~TargetLoweringObjectFileMachO() {
515 // If we have the MachO uniquing map, free it.
516 delete (MachOUniqueMapTy*)UniquingMap;
520 const MCSectionMachO *TargetLoweringObjectFileMachO::
521 getMachOSection(const StringRef &Segment, const StringRef &Section,
522 unsigned TypeAndAttributes,
523 unsigned Reserved2, SectionKind Kind) const {
524 // We unique sections by their segment/section pair. The returned section
525 // may not have the same flags as the requested section, if so this should be
526 // diagnosed by the client as an error.
528 // Create the map if it doesn't already exist.
529 if (UniquingMap == 0)
530 UniquingMap = new MachOUniqueMapTy();
531 MachOUniqueMapTy &Map = *(MachOUniqueMapTy*)UniquingMap;
533 // Form the name to look up.
534 SmallString<64> Name;
535 Name.append(Segment.begin(), Segment.end());
537 Name.append(Section.begin(), Section.end());
539 // Do the lookup, if we have a hit, return it.
540 const MCSectionMachO *&Entry = Map[StringRef(Name.data(), Name.size())];
541 if (Entry) return Entry;
543 // Otherwise, return a new section.
544 return Entry = MCSectionMachO::Create(Segment, Section, TypeAndAttributes,
545 Reserved2, Kind, getContext());
549 void TargetLoweringObjectFileMachO::Initialize(MCContext &Ctx,
550 const TargetMachine &TM) {
551 TargetLoweringObjectFile::Initialize(Ctx, TM);
554 = getMachOSection("__TEXT", "__text",
555 MCSectionMachO::S_ATTR_PURE_INSTRUCTIONS,
556 SectionKind::getText());
558 = getMachOSection("__DATA", "__data", 0, SectionKind::getDataRel());
560 CStringSection // .cstring
561 = getMachOSection("__TEXT", "__cstring", MCSectionMachO::S_CSTRING_LITERALS,
562 SectionKind::getMergeable1ByteCString());
564 = getMachOSection("__TEXT","__ustring", 0,
565 SectionKind::getMergeable2ByteCString());
566 FourByteConstantSection // .literal4
567 = getMachOSection("__TEXT", "__literal4", MCSectionMachO::S_4BYTE_LITERALS,
568 SectionKind::getMergeableConst4());
569 EightByteConstantSection // .literal8
570 = getMachOSection("__TEXT", "__literal8", MCSectionMachO::S_8BYTE_LITERALS,
571 SectionKind::getMergeableConst8());
573 // ld_classic doesn't support .literal16 in 32-bit mode, and ld64 falls back
574 // to using it in -static mode.
575 SixteenByteConstantSection = 0;
576 if (TM.getRelocationModel() != Reloc::Static &&
577 TM.getTargetData()->getPointerSize() == 32)
578 SixteenByteConstantSection = // .literal16
579 getMachOSection("__TEXT", "__literal16",MCSectionMachO::S_16BYTE_LITERALS,
580 SectionKind::getMergeableConst16());
582 ReadOnlySection // .const
583 = getMachOSection("__TEXT", "__const", 0, SectionKind::getReadOnly());
586 = getMachOSection("__TEXT", "__textcoal_nt",
587 MCSectionMachO::S_COALESCED |
588 MCSectionMachO::S_ATTR_PURE_INSTRUCTIONS,
589 SectionKind::getText());
591 = getMachOSection("__TEXT", "__const_coal", MCSectionMachO::S_COALESCED,
592 SectionKind::getText());
594 = getMachOSection("__DATA","__const_coal", MCSectionMachO::S_COALESCED,
595 SectionKind::getText());
596 ConstDataSection // .const_data
597 = getMachOSection("__DATA", "__const", 0,
598 SectionKind::getReadOnlyWithRel());
600 = getMachOSection("__DATA","__datacoal_nt", MCSectionMachO::S_COALESCED,
601 SectionKind::getDataRel());
604 LazySymbolPointerSection
605 = getMachOSection("__DATA", "__la_symbol_ptr",
606 MCSectionMachO::S_LAZY_SYMBOL_POINTERS,
607 SectionKind::getMetadata());
608 NonLazySymbolPointerSection
609 = getMachOSection("__DATA", "__nl_symbol_ptr",
610 MCSectionMachO::S_NON_LAZY_SYMBOL_POINTERS,
611 SectionKind::getMetadata());
613 if (TM.getRelocationModel() == Reloc::Static) {
615 = getMachOSection("__TEXT", "__constructor", 0,SectionKind::getDataRel());
617 = getMachOSection("__TEXT", "__destructor", 0, SectionKind::getDataRel());
620 = getMachOSection("__DATA", "__mod_init_func",
621 MCSectionMachO::S_MOD_INIT_FUNC_POINTERS,
622 SectionKind::getDataRel());
624 = getMachOSection("__DATA", "__mod_term_func",
625 MCSectionMachO::S_MOD_TERM_FUNC_POINTERS,
626 SectionKind::getDataRel());
629 // Exception Handling.
630 LSDASection = getMachOSection("__DATA", "__gcc_except_tab", 0,
631 SectionKind::getDataRel());
633 getMachOSection("__TEXT", "__eh_frame",
634 MCSectionMachO::S_COALESCED |
635 MCSectionMachO::S_ATTR_NO_TOC |
636 MCSectionMachO::S_ATTR_STRIP_STATIC_SYMS |
637 MCSectionMachO::S_ATTR_LIVE_SUPPORT,
638 SectionKind::getReadOnly());
640 // Debug Information.
642 getMachOSection("__DWARF", "__debug_abbrev", MCSectionMachO::S_ATTR_DEBUG,
643 SectionKind::getMetadata());
645 getMachOSection("__DWARF", "__debug_info", MCSectionMachO::S_ATTR_DEBUG,
646 SectionKind::getMetadata());
648 getMachOSection("__DWARF", "__debug_line", MCSectionMachO::S_ATTR_DEBUG,
649 SectionKind::getMetadata());
651 getMachOSection("__DWARF", "__debug_frame", MCSectionMachO::S_ATTR_DEBUG,
652 SectionKind::getMetadata());
653 DwarfPubNamesSection =
654 getMachOSection("__DWARF", "__debug_pubnames", MCSectionMachO::S_ATTR_DEBUG,
655 SectionKind::getMetadata());
656 DwarfPubTypesSection =
657 getMachOSection("__DWARF", "__debug_pubtypes", MCSectionMachO::S_ATTR_DEBUG,
658 SectionKind::getMetadata());
660 getMachOSection("__DWARF", "__debug_str", MCSectionMachO::S_ATTR_DEBUG,
661 SectionKind::getMetadata());
663 getMachOSection("__DWARF", "__debug_loc", MCSectionMachO::S_ATTR_DEBUG,
664 SectionKind::getMetadata());
665 DwarfARangesSection =
666 getMachOSection("__DWARF", "__debug_aranges", MCSectionMachO::S_ATTR_DEBUG,
667 SectionKind::getMetadata());
669 getMachOSection("__DWARF", "__debug_ranges", MCSectionMachO::S_ATTR_DEBUG,
670 SectionKind::getMetadata());
671 DwarfMacroInfoSection =
672 getMachOSection("__DWARF", "__debug_macinfo", MCSectionMachO::S_ATTR_DEBUG,
673 SectionKind::getMetadata());
674 DwarfDebugInlineSection =
675 getMachOSection("__DWARF", "__debug_inlined", MCSectionMachO::S_ATTR_DEBUG,
676 SectionKind::getMetadata());
679 const MCSection *TargetLoweringObjectFileMachO::
680 getExplicitSectionGlobal(const GlobalValue *GV, SectionKind Kind,
681 Mangler *Mang, const TargetMachine &TM) const {
682 // Parse the section specifier and create it if valid.
683 StringRef Segment, Section;
684 unsigned TAA, StubSize;
685 std::string ErrorCode =
686 MCSectionMachO::ParseSectionSpecifier(GV->getSection(), Segment, Section,
688 if (!ErrorCode.empty()) {
689 // If invalid, report the error with llvm_report_error.
690 llvm_report_error("Global variable '" + GV->getNameStr() +
691 "' has an invalid section specifier '" + GV->getSection()+
692 "': " + ErrorCode + ".");
693 // Fall back to dropping it into the data section.
698 const MCSectionMachO *S =
699 getMachOSection(Segment, Section, TAA, StubSize, Kind);
701 // Okay, now that we got the section, verify that the TAA & StubSize agree.
702 // If the user declared multiple globals with different section flags, we need
703 // to reject it here.
704 if (S->getTypeAndAttributes() != TAA || S->getStubSize() != StubSize) {
705 // If invalid, report the error with llvm_report_error.
706 llvm_report_error("Global variable '" + GV->getNameStr() +
707 "' section type or attributes does not match previous"
708 " section specifier");
716 const MCSection *TargetLoweringObjectFileMachO::
717 SelectSectionForGlobal(const GlobalValue *GV, SectionKind Kind,
718 Mangler *Mang, const TargetMachine &TM) const {
719 assert(!Kind.isThreadLocal() && "Darwin doesn't support TLS");
722 return GV->isWeakForLinker() ? TextCoalSection : TextSection;
724 // If this is weak/linkonce, put this in a coalescable section, either in text
725 // or data depending on if it is writable.
726 if (GV->isWeakForLinker()) {
727 if (Kind.isReadOnly())
728 return ConstTextCoalSection;
729 return DataCoalSection;
732 // FIXME: Alignment check should be handled by section classifier.
733 if (Kind.isMergeable1ByteCString() ||
734 Kind.isMergeable2ByteCString()) {
735 if (TM.getTargetData()->getPreferredAlignment(
736 cast<GlobalVariable>(GV)) < 32) {
737 if (Kind.isMergeable1ByteCString())
738 return CStringSection;
739 assert(Kind.isMergeable2ByteCString());
740 return UStringSection;
744 if (Kind.isMergeableConst()) {
745 if (Kind.isMergeableConst4())
746 return FourByteConstantSection;
747 if (Kind.isMergeableConst8())
748 return EightByteConstantSection;
749 if (Kind.isMergeableConst16() && SixteenByteConstantSection)
750 return SixteenByteConstantSection;
753 // Otherwise, if it is readonly, but not something we can specially optimize,
754 // just drop it in .const.
755 if (Kind.isReadOnly())
756 return ReadOnlySection;
758 // If this is marked const, put it into a const section. But if the dynamic
759 // linker needs to write to it, put it in the data segment.
760 if (Kind.isReadOnlyWithRel())
761 return ConstDataSection;
763 // Otherwise, just drop the variable in the normal data section.
768 TargetLoweringObjectFileMachO::getSectionForConstant(SectionKind Kind) const {
769 // If this constant requires a relocation, we have to put it in the data
770 // segment, not in the text segment.
771 if (Kind.isDataRel())
772 return ConstDataSection;
774 if (Kind.isMergeableConst4())
775 return FourByteConstantSection;
776 if (Kind.isMergeableConst8())
777 return EightByteConstantSection;
778 if (Kind.isMergeableConst16() && SixteenByteConstantSection)
779 return SixteenByteConstantSection;
780 return ReadOnlySection; // .const
783 /// shouldEmitUsedDirectiveFor - This hook allows targets to selectively decide
784 /// not to emit the UsedDirective for some symbols in llvm.used.
785 // FIXME: REMOVE this (rdar://7071300)
786 bool TargetLoweringObjectFileMachO::
787 shouldEmitUsedDirectiveFor(const GlobalValue *GV, Mangler *Mang) const {
788 /// On Darwin, internally linked data beginning with "L" or "l" does not have
789 /// the directive emitted (this occurs in ObjC metadata).
790 if (!GV) return false;
792 // Check whether the mangled name has the "Private" or "LinkerPrivate" prefix.
793 if (GV->hasLocalLinkage() && !isa<Function>(GV)) {
794 // FIXME: ObjC metadata is currently emitted as internal symbols that have
795 // \1L and \0l prefixes on them. Fix them to be Private/LinkerPrivate and
796 // this horrible hack can go away.
797 const std::string &Name = Mang->getMangledName(GV);
798 if (Name[0] == 'L' || Name[0] == 'l')
806 //===----------------------------------------------------------------------===//
808 //===----------------------------------------------------------------------===//
811 const MCSection *TargetLoweringObjectFileCOFF::
812 getCOFFSection(const char *Name, bool isDirective, SectionKind Kind) const {
813 if (MCSection *S = getContext().GetSection(Name))
815 return MCSectionCOFF::Create(Name, isDirective, Kind, getContext());
818 void TargetLoweringObjectFileCOFF::Initialize(MCContext &Ctx,
819 const TargetMachine &TM) {
820 TargetLoweringObjectFile::Initialize(Ctx, TM);
821 TextSection = getCOFFSection("\t.text", true, SectionKind::getText());
822 DataSection = getCOFFSection("\t.data", true, SectionKind::getDataRel());
824 getCOFFSection(".ctors", false, SectionKind::getDataRel());
826 getCOFFSection(".dtors", false, SectionKind::getDataRel());
830 // FIXME: Don't use 'directive' mode here.
832 getCOFFSection("\t.section\t.debug_abbrev,\"dr\"",
833 true, SectionKind::getMetadata());
835 getCOFFSection("\t.section\t.debug_info,\"dr\"",
836 true, SectionKind::getMetadata());
838 getCOFFSection("\t.section\t.debug_line,\"dr\"",
839 true, SectionKind::getMetadata());
841 getCOFFSection("\t.section\t.debug_frame,\"dr\"",
842 true, SectionKind::getMetadata());
843 DwarfPubNamesSection =
844 getCOFFSection("\t.section\t.debug_pubnames,\"dr\"",
845 true, SectionKind::getMetadata());
846 DwarfPubTypesSection =
847 getCOFFSection("\t.section\t.debug_pubtypes,\"dr\"",
848 true, SectionKind::getMetadata());
850 getCOFFSection("\t.section\t.debug_str,\"dr\"",
851 true, SectionKind::getMetadata());
853 getCOFFSection("\t.section\t.debug_loc,\"dr\"",
854 true, SectionKind::getMetadata());
855 DwarfARangesSection =
856 getCOFFSection("\t.section\t.debug_aranges,\"dr\"",
857 true, SectionKind::getMetadata());
859 getCOFFSection("\t.section\t.debug_ranges,\"dr\"",
860 true, SectionKind::getMetadata());
861 DwarfMacroInfoSection =
862 getCOFFSection("\t.section\t.debug_macinfo,\"dr\"",
863 true, SectionKind::getMetadata());
866 const MCSection *TargetLoweringObjectFileCOFF::
867 getExplicitSectionGlobal(const GlobalValue *GV, SectionKind Kind,
868 Mangler *Mang, const TargetMachine &TM) const {
869 return getCOFFSection(GV->getSection().c_str(), false, Kind);
872 static const char *getCOFFSectionPrefixForUniqueGlobal(SectionKind Kind) {
874 return ".text$linkonce";
875 if (Kind.isWriteable())
876 return ".data$linkonce";
877 return ".rdata$linkonce";
881 const MCSection *TargetLoweringObjectFileCOFF::
882 SelectSectionForGlobal(const GlobalValue *GV, SectionKind Kind,
883 Mangler *Mang, const TargetMachine &TM) const {
884 assert(!Kind.isThreadLocal() && "Doesn't support TLS");
886 // If this global is linkonce/weak and the target handles this by emitting it
887 // into a 'uniqued' section name, create and return the section now.
888 if (GV->isWeakForLinker()) {
889 const char *Prefix = getCOFFSectionPrefixForUniqueGlobal(Kind);
890 std::string Name = Mang->makeNameProper(GV->getNameStr());
891 return getCOFFSection((Prefix+Name).c_str(), false, Kind);
895 return getTextSection();
897 return getDataSection();