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/GlobalVariable.h"
19 #include "llvm/MC/MCContext.h"
20 #include "llvm/MC/MCSection.h"
21 #include "llvm/Target/TargetMachine.h"
22 #include "llvm/Target/TargetData.h"
23 #include "llvm/Target/TargetOptions.h"
24 #include "llvm/Support/Mangler.h"
25 #include "llvm/ADT/StringExtras.h"
28 //===----------------------------------------------------------------------===//
30 //===----------------------------------------------------------------------===//
32 TargetLoweringObjectFile::TargetLoweringObjectFile() : Ctx(0) {
37 StaticCtorSection = 0;
38 StaticDtorSection = 0;
42 DwarfAbbrevSection = 0;
45 DwarfFrameSection = 0;
46 DwarfPubNamesSection = 0;
47 DwarfPubTypesSection = 0;
48 DwarfDebugInlineSection = 0;
51 DwarfARangesSection = 0;
52 DwarfRangesSection = 0;
53 DwarfMacroInfoSection = 0;
56 TargetLoweringObjectFile::~TargetLoweringObjectFile() {
59 static bool isSuitableForBSS(const GlobalVariable *GV) {
60 Constant *C = GV->getInitializer();
62 // Must have zero initializer.
63 if (!C->isNullValue())
66 // Leave constant zeros in readonly constant sections, so they can be shared.
70 // If the global has an explicit section specified, don't put it in BSS.
71 if (!GV->getSection().empty())
74 // If -nozero-initialized-in-bss is specified, don't ever use BSS.
78 // Otherwise, put it in BSS!
82 /// IsNullTerminatedString - Return true if the specified constant (which is
83 /// known to have a type that is an array of 1/2/4 byte elements) ends with a
84 /// nul value and contains no other nuls in it.
85 static bool IsNullTerminatedString(const Constant *C) {
86 const ArrayType *ATy = cast<ArrayType>(C->getType());
88 // First check: is we have constant array of i8 terminated with zero
89 if (const ConstantArray *CVA = dyn_cast<ConstantArray>(C)) {
90 if (ATy->getNumElements() == 0) return false;
93 dyn_cast<ConstantInt>(CVA->getOperand(ATy->getNumElements()-1));
94 if (Null == 0 || Null->getZExtValue() != 0)
95 return false; // Not null terminated.
97 // Verify that the null doesn't occur anywhere else in the string.
98 for (unsigned i = 0, e = ATy->getNumElements()-1; i != e; ++i)
99 // Reject constantexpr elements etc.
100 if (!isa<ConstantInt>(CVA->getOperand(i)) ||
101 CVA->getOperand(i) == Null)
106 // Another possibility: [1 x i8] zeroinitializer
107 if (isa<ConstantAggregateZero>(C))
108 return ATy->getNumElements() == 1;
113 /// SectionKindForGlobal - This is a top-level target-independent classifier for
114 /// a global variable. Given an global variable and information from TM, it
115 /// classifies the global in a variety of ways that make various target
116 /// implementations simpler. The target implementation is free to ignore this
117 /// extra info of course.
118 static SectionKind SectionKindForGlobal(const GlobalValue *GV,
119 const TargetMachine &TM) {
120 Reloc::Model ReloModel = TM.getRelocationModel();
122 // Early exit - functions should be always in text sections.
123 const GlobalVariable *GVar = dyn_cast<GlobalVariable>(GV);
125 return SectionKind::getText();
128 // Handle thread-local data first.
129 if (GVar->isThreadLocal()) {
130 if (isSuitableForBSS(GVar))
131 return SectionKind::getThreadBSS();
132 return SectionKind::getThreadData();
135 // Variable can be easily put to BSS section.
136 if (isSuitableForBSS(GVar))
137 return SectionKind::getBSS();
139 Constant *C = GVar->getInitializer();
141 // If the global is marked constant, we can put it into a mergable section,
142 // a mergable string section, or general .data if it contains relocations.
143 if (GVar->isConstant()) {
144 // If the initializer for the global contains something that requires a
145 // relocation, then we may have to drop this into a wriable data section
146 // even though it is marked const.
147 switch (C->getRelocationInfo()) {
148 default: llvm_unreachable("unknown relocation info kind");
149 case Constant::NoRelocation:
150 // If initializer is a null-terminated string, put it in a "cstring"
151 // section of the right width.
152 if (const ArrayType *ATy = dyn_cast<ArrayType>(C->getType())) {
153 if (const IntegerType *ITy =
154 dyn_cast<IntegerType>(ATy->getElementType())) {
155 if ((ITy->getBitWidth() == 8 || ITy->getBitWidth() == 16 ||
156 ITy->getBitWidth() == 32) &&
157 IsNullTerminatedString(C)) {
158 if (ITy->getBitWidth() == 8)
159 return SectionKind::getMergeable1ByteCString();
160 if (ITy->getBitWidth() == 16)
161 return SectionKind::getMergeable2ByteCString();
163 assert(ITy->getBitWidth() == 32 && "Unknown width");
164 return SectionKind::getMergeable4ByteCString();
169 // Otherwise, just drop it into a mergable constant section. If we have
170 // a section for this size, use it, otherwise use the arbitrary sized
172 switch (TM.getTargetData()->getTypeAllocSize(C->getType())) {
173 case 4: return SectionKind::getMergeableConst4();
174 case 8: return SectionKind::getMergeableConst8();
175 case 16: return SectionKind::getMergeableConst16();
176 default: return SectionKind::getMergeableConst();
179 case Constant::LocalRelocation:
180 // In static relocation model, the linker will resolve all addresses, so
181 // the relocation entries will actually be constants by the time the app
182 // starts up. However, we can't put this into a mergable section, because
183 // the linker doesn't take relocations into consideration when it tries to
184 // merge entries in the section.
185 if (ReloModel == Reloc::Static)
186 return SectionKind::getReadOnly();
188 // Otherwise, the dynamic linker needs to fix it up, put it in the
189 // writable data.rel.local section.
190 return SectionKind::getReadOnlyWithRelLocal();
192 case Constant::GlobalRelocations:
193 // In static relocation model, the linker will resolve all addresses, so
194 // the relocation entries will actually be constants by the time the app
195 // starts up. However, we can't put this into a mergable section, because
196 // the linker doesn't take relocations into consideration when it tries to
197 // merge entries in the section.
198 if (ReloModel == Reloc::Static)
199 return SectionKind::getReadOnly();
201 // Otherwise, the dynamic linker needs to fix it up, put it in the
202 // writable data.rel section.
203 return SectionKind::getReadOnlyWithRel();
207 // Okay, this isn't a constant. If the initializer for the global is going
208 // to require a runtime relocation by the dynamic linker, put it into a more
209 // specific section to improve startup time of the app. This coalesces these
210 // globals together onto fewer pages, improving the locality of the dynamic
212 if (ReloModel == Reloc::Static)
213 return SectionKind::getDataNoRel();
215 switch (C->getRelocationInfo()) {
216 default: llvm_unreachable("unknown relocation info kind");
217 case Constant::NoRelocation:
218 return SectionKind::getDataNoRel();
219 case Constant::LocalRelocation:
220 return SectionKind::getDataRelLocal();
221 case Constant::GlobalRelocations:
222 return SectionKind::getDataRel();
226 /// SectionForGlobal - This method computes the appropriate section to emit
227 /// the specified global variable or function definition. This should not
228 /// be passed external (or available externally) globals.
229 const MCSection *TargetLoweringObjectFile::
230 SectionForGlobal(const GlobalValue *GV, Mangler *Mang,
231 const TargetMachine &TM) const {
232 assert(!GV->isDeclaration() && !GV->hasAvailableExternallyLinkage() &&
233 "Can only be used for global definitions");
235 SectionKind Kind = SectionKindForGlobal(GV, TM);
237 // Select section name.
238 if (GV->hasSection()) {
239 // If the target has special section hacks for specifically named globals,
241 if (const MCSection *TS = getSpecialCasedSectionGlobals(GV, Mang, Kind))
244 // If the target has magic semantics for certain section names, make sure to
245 // pick up the flags. This allows the user to write things with attribute
246 // section and still get the appropriate section flags printed.
247 Kind = getKindForNamedSection(GV->getSection().c_str(), Kind);
249 return getOrCreateSection(GV->getSection().c_str(), false, Kind);
253 // Use default section depending on the 'type' of global
254 return SelectSectionForGlobal(GV, Kind, Mang, TM);
257 // Lame default implementation. Calculate the section name for global.
259 TargetLoweringObjectFile::SelectSectionForGlobal(const GlobalValue *GV,
262 const TargetMachine &TM) const{
263 assert(!Kind.isThreadLocal() && "Doesn't support TLS");
266 return getTextSection();
268 if (Kind.isBSS() && BSSSection != 0)
271 if (Kind.isReadOnly() && ReadOnlySection != 0)
272 return ReadOnlySection;
274 return getDataSection();
277 /// getSectionForConstant - Given a mergable constant with the
278 /// specified size and relocation information, return a section that it
279 /// should be placed in.
281 TargetLoweringObjectFile::getSectionForConstant(SectionKind Kind) const {
282 if (Kind.isReadOnly() && ReadOnlySection != 0)
283 return ReadOnlySection;
289 const MCSection *TargetLoweringObjectFile::
290 getOrCreateSection(const char *Name, bool isDirective, SectionKind Kind) const {
291 if (MCSection *S = Ctx->GetSection(Name))
293 return MCSection::Create(Name, isDirective, Kind, *Ctx);
298 //===----------------------------------------------------------------------===//
300 //===----------------------------------------------------------------------===//
302 void TargetLoweringObjectFileELF::Initialize(MCContext &Ctx,
303 const TargetMachine &TM) {
304 TargetLoweringObjectFile::Initialize(Ctx, TM);
306 BSSSection = getOrCreateSection("\t.bss", true, SectionKind::getBSS());
308 // PPC/Linux doesn't support the .bss directive, it needs .section .bss.
309 // FIXME: Does .section .bss work everywhere??
310 // FIXME2: this should just be handle by the section printer. We should get
311 // away from syntactic view of the sections and MCSection should just be a
313 BSSSection = getOrCreateSection("\t.bss", false, SectionKind::getBSS());
316 TextSection = getOrCreateSection("\t.text", true, SectionKind::getText());
317 DataSection = getOrCreateSection("\t.data", true, SectionKind::getDataRel());
319 getOrCreateSection("\t.rodata", false, SectionKind::getReadOnly());
321 getOrCreateSection("\t.tdata", false, SectionKind::getThreadData());
323 TLSBSSSection = getOrCreateSection("\t.tbss", false,
324 SectionKind::getThreadBSS());
326 DataRelSection = getOrCreateSection("\t.data.rel", false,
327 SectionKind::getDataRel());
328 DataRelLocalSection = getOrCreateSection("\t.data.rel.local", false,
329 SectionKind::getDataRelLocal());
330 DataRelROSection = getOrCreateSection("\t.data.rel.ro", false,
331 SectionKind::getReadOnlyWithRel());
332 DataRelROLocalSection =
333 getOrCreateSection("\t.data.rel.ro.local", false,
334 SectionKind::getReadOnlyWithRelLocal());
336 MergeableConst4Section = getOrCreateSection(".rodata.cst4", false,
337 SectionKind::getMergeableConst4());
338 MergeableConst8Section = getOrCreateSection(".rodata.cst8", false,
339 SectionKind::getMergeableConst8());
340 MergeableConst16Section = getOrCreateSection(".rodata.cst16", false,
341 SectionKind::getMergeableConst16());
344 getOrCreateSection(".ctors", false, SectionKind::getDataRel());
346 getOrCreateSection(".dtors", false, SectionKind::getDataRel());
348 // Exception Handling Sections.
350 // FIXME: We're emitting LSDA info into a readonly section on ELF, even though
351 // it contains relocatable pointers. In PIC mode, this is probably a big
352 // runtime hit for C++ apps. Either the contents of the LSDA need to be
353 // adjusted or this should be a data section.
355 getOrCreateSection(".gcc_except_table", false, SectionKind::getReadOnly());
357 getOrCreateSection(".eh_frame", false, SectionKind::getDataRel());
359 // Debug Info Sections.
361 getOrCreateSection(".debug_abbrev", false, SectionKind::getMetadata());
363 getOrCreateSection(".debug_info", false, SectionKind::getMetadata());
365 getOrCreateSection(".debug_line", false, SectionKind::getMetadata());
367 getOrCreateSection(".debug_frame", false, SectionKind::getMetadata());
368 DwarfPubNamesSection =
369 getOrCreateSection(".debug_pubnames", false, SectionKind::getMetadata());
370 DwarfPubTypesSection =
371 getOrCreateSection(".debug_pubtypes", false, SectionKind::getMetadata());
373 getOrCreateSection(".debug_str", false, SectionKind::getMetadata());
375 getOrCreateSection(".debug_loc", false, SectionKind::getMetadata());
376 DwarfARangesSection =
377 getOrCreateSection(".debug_aranges", false, SectionKind::getMetadata());
379 getOrCreateSection(".debug_ranges", false, SectionKind::getMetadata());
380 DwarfMacroInfoSection =
381 getOrCreateSection(".debug_macinfo", false, SectionKind::getMetadata());
385 SectionKind TargetLoweringObjectFileELF::
386 getKindForNamedSection(const char *Name, SectionKind K) const {
387 if (Name[0] != '.') return K;
389 // Some lame default implementation based on some magic section names.
390 if (strncmp(Name, ".gnu.linkonce.b.", 16) == 0 ||
391 strncmp(Name, ".llvm.linkonce.b.", 17) == 0 ||
392 strncmp(Name, ".gnu.linkonce.sb.", 17) == 0 ||
393 strncmp(Name, ".llvm.linkonce.sb.", 18) == 0)
394 return SectionKind::getBSS();
396 if (strcmp(Name, ".tdata") == 0 ||
397 strncmp(Name, ".tdata.", 7) == 0 ||
398 strncmp(Name, ".gnu.linkonce.td.", 17) == 0 ||
399 strncmp(Name, ".llvm.linkonce.td.", 18) == 0)
400 return SectionKind::getThreadData();
402 if (strcmp(Name, ".tbss") == 0 ||
403 strncmp(Name, ".tbss.", 6) == 0 ||
404 strncmp(Name, ".gnu.linkonce.tb.", 17) == 0 ||
405 strncmp(Name, ".llvm.linkonce.tb.", 18) == 0)
406 return SectionKind::getThreadBSS();
411 void TargetLoweringObjectFileELF::
412 getSectionFlagsAsString(SectionKind Kind, SmallVectorImpl<char> &Str) const {
416 if (!Kind.isMetadata())
420 if (Kind.isWriteable())
422 if (Kind.isMergeable1ByteCString() ||
423 Kind.isMergeable2ByteCString() ||
424 Kind.isMergeable4ByteCString() ||
425 Kind.isMergeableConst4() ||
426 Kind.isMergeableConst8() ||
427 Kind.isMergeableConst16())
429 if (Kind.isMergeable1ByteCString() ||
430 Kind.isMergeable2ByteCString() ||
431 Kind.isMergeable4ByteCString())
433 if (Kind.isThreadLocal())
439 // If comment string is '@', e.g. as on ARM - use '%' instead
446 if (Kind.isBSS() || Kind.isThreadBSS())
449 KindStr = "progbits";
451 Str.append(KindStr, KindStr+strlen(KindStr));
453 if (Kind.isMergeable1ByteCString()) {
456 } else if (Kind.isMergeable2ByteCString()) {
459 } else if (Kind.isMergeable4ByteCString()) {
462 } else if (Kind.isMergeableConst4()) {
465 } else if (Kind.isMergeableConst8()) {
468 } else if (Kind.isMergeableConst16()) {
476 static const char *getSectionPrefixForUniqueGlobal(SectionKind Kind) {
477 if (Kind.isText()) return ".gnu.linkonce.t.";
478 if (Kind.isReadOnly()) return ".gnu.linkonce.r.";
480 if (Kind.isThreadData()) return ".gnu.linkonce.td.";
481 if (Kind.isThreadBSS()) return ".gnu.linkonce.tb.";
483 if (Kind.isBSS()) return ".gnu.linkonce.b.";
484 if (Kind.isDataNoRel()) return ".gnu.linkonce.d.";
485 if (Kind.isDataRelLocal()) return ".gnu.linkonce.d.rel.local.";
486 if (Kind.isDataRel()) return ".gnu.linkonce.d.rel.";
487 if (Kind.isReadOnlyWithRelLocal()) return ".gnu.linkonce.d.rel.ro.local.";
489 assert(Kind.isReadOnlyWithRel() && "Unknown section kind");
490 return ".gnu.linkonce.d.rel.ro.";
493 const MCSection *TargetLoweringObjectFileELF::
494 SelectSectionForGlobal(const GlobalValue *GV, SectionKind Kind,
495 Mangler *Mang, const TargetMachine &TM) const {
497 // If this global is linkonce/weak and the target handles this by emitting it
498 // into a 'uniqued' section name, create and return the section now.
499 if (GV->isWeakForLinker()) {
500 const char *Prefix = getSectionPrefixForUniqueGlobal(Kind);
501 std::string Name = Mang->makeNameProper(GV->getNameStr());
502 return getOrCreateSection((Prefix+Name).c_str(), false, Kind);
505 if (Kind.isText()) return TextSection;
507 if (Kind.isMergeable1ByteCString() ||
508 Kind.isMergeable2ByteCString() ||
509 Kind.isMergeable4ByteCString()) {
511 // We also need alignment here.
512 // FIXME: this is getting the alignment of the character, not the
513 // alignment of the global!
515 TM.getTargetData()->getPreferredAlignment(cast<GlobalVariable>(GV));
517 const char *SizeSpec = ".rodata.str1.";
518 if (Kind.isMergeable2ByteCString())
519 SizeSpec = ".rodata.str2.";
520 else if (Kind.isMergeable4ByteCString())
521 SizeSpec = ".rodata.str4.";
523 assert(Kind.isMergeable1ByteCString() && "unknown string width");
526 std::string Name = SizeSpec + utostr(Align);
527 return getOrCreateSection(Name.c_str(), false, Kind);
530 if (Kind.isMergeableConst()) {
531 if (Kind.isMergeableConst4())
532 return MergeableConst4Section;
533 if (Kind.isMergeableConst8())
534 return MergeableConst8Section;
535 if (Kind.isMergeableConst16())
536 return MergeableConst16Section;
537 return ReadOnlySection; // .const
540 if (Kind.isReadOnly()) return ReadOnlySection;
542 if (Kind.isThreadData()) return TLSDataSection;
543 if (Kind.isThreadBSS()) return TLSBSSSection;
545 if (Kind.isBSS()) return BSSSection;
547 if (Kind.isDataNoRel()) return DataSection;
548 if (Kind.isDataRelLocal()) return DataRelLocalSection;
549 if (Kind.isDataRel()) return DataRelSection;
550 if (Kind.isReadOnlyWithRelLocal()) return DataRelROLocalSection;
552 assert(Kind.isReadOnlyWithRel() && "Unknown section kind");
553 return DataRelROSection;
556 /// getSectionForConstant - Given a mergeable constant with the
557 /// specified size and relocation information, return a section that it
558 /// should be placed in.
559 const MCSection *TargetLoweringObjectFileELF::
560 getSectionForConstant(SectionKind Kind) const {
561 if (Kind.isMergeableConst4())
562 return MergeableConst4Section;
563 if (Kind.isMergeableConst8())
564 return MergeableConst8Section;
565 if (Kind.isMergeableConst16())
566 return MergeableConst16Section;
567 if (Kind.isReadOnly())
568 return ReadOnlySection;
570 if (Kind.isReadOnlyWithRelLocal()) return DataRelROLocalSection;
571 assert(Kind.isReadOnlyWithRel() && "Unknown section kind");
572 return DataRelROSection;
575 //===----------------------------------------------------------------------===//
577 //===----------------------------------------------------------------------===//
579 const MCSection *TargetLoweringObjectFileMachO::
580 getMachOSection(const char *Name, bool isDirective, SectionKind K) {
581 // FOR NOW, Just forward.
582 return getOrCreateSection(Name, isDirective, K);
587 void TargetLoweringObjectFileMachO::Initialize(MCContext &Ctx,
588 const TargetMachine &TM) {
589 TargetLoweringObjectFile::Initialize(Ctx, TM);
590 TextSection = getOrCreateSection("\t.text", true,
591 SectionKind::getText());
592 DataSection = getOrCreateSection("\t.data", true,
593 SectionKind::getDataRel());
595 CStringSection = getOrCreateSection("\t.cstring", true,
596 SectionKind::getMergeable1ByteCString());
597 UStringSection = getOrCreateSection("__TEXT,__ustring", false,
598 SectionKind::getMergeable2ByteCString());
599 FourByteConstantSection = getOrCreateSection("\t.literal4\n", true,
600 SectionKind::getMergeableConst4());
601 EightByteConstantSection = getOrCreateSection("\t.literal8\n", true,
602 SectionKind::getMergeableConst8());
604 // ld_classic doesn't support .literal16 in 32-bit mode, and ld64 falls back
605 // to using it in -static mode.
606 if (TM.getRelocationModel() != Reloc::Static &&
607 TM.getTargetData()->getPointerSize() == 32)
608 SixteenByteConstantSection =
609 getOrCreateSection("\t.literal16\n", true,
610 SectionKind::getMergeableConst16());
612 SixteenByteConstantSection = 0;
614 ReadOnlySection = getOrCreateSection("\t.const", true,
615 SectionKind::getReadOnly());
618 getOrCreateSection("\t__TEXT,__textcoal_nt,coalesced,pure_instructions",
619 false, SectionKind::getText());
620 ConstTextCoalSection = getOrCreateSection("\t__TEXT,__const_coal,coalesced",
622 SectionKind::getText());
623 ConstDataCoalSection = getOrCreateSection("\t__DATA,__const_coal,coalesced",
625 SectionKind::getText());
626 ConstDataSection = getOrCreateSection("\t.const_data", true,
627 SectionKind::getReadOnlyWithRel());
628 DataCoalSection = getOrCreateSection("\t__DATA,__datacoal_nt,coalesced",
630 SectionKind::getDataRel());
632 if (TM.getRelocationModel() == Reloc::Static) {
634 getOrCreateSection(".constructor", true, SectionKind::getDataRel());
636 getOrCreateSection(".destructor", true, SectionKind::getDataRel());
639 getOrCreateSection(".mod_init_func", true, SectionKind::getDataRel());
641 getOrCreateSection(".mod_term_func", true, SectionKind::getDataRel());
644 // Exception Handling.
645 LSDASection = getOrCreateSection("__DATA,__gcc_except_tab", false,
646 SectionKind::getDataRel());
648 getOrCreateSection("__TEXT,__eh_frame,coalesced,no_toc+strip_static_syms"
649 "+live_support", false, SectionKind::getReadOnly());
651 // Debug Information.
652 // FIXME: Don't use 'directive' syntax: need flags for debug/regular??
653 // FIXME: Need __DWARF segment.
655 getOrCreateSection(".section __DWARF,__debug_abbrev,regular,debug", true,
656 SectionKind::getMetadata());
658 getOrCreateSection(".section __DWARF,__debug_info,regular,debug", true,
659 SectionKind::getMetadata());
661 getOrCreateSection(".section __DWARF,__debug_line,regular,debug", true,
662 SectionKind::getMetadata());
664 getOrCreateSection(".section __DWARF,__debug_frame,regular,debug", true,
665 SectionKind::getMetadata());
666 DwarfPubNamesSection =
667 getOrCreateSection(".section __DWARF,__debug_pubnames,regular,debug", true,
668 SectionKind::getMetadata());
669 DwarfPubTypesSection =
670 getOrCreateSection(".section __DWARF,__debug_pubtypes,regular,debug", true,
671 SectionKind::getMetadata());
673 getOrCreateSection(".section __DWARF,__debug_str,regular,debug", true,
674 SectionKind::getMetadata());
676 getOrCreateSection(".section __DWARF,__debug_loc,regular,debug", true,
677 SectionKind::getMetadata());
678 DwarfARangesSection =
679 getOrCreateSection(".section __DWARF,__debug_aranges,regular,debug", true,
680 SectionKind::getMetadata());
682 getOrCreateSection(".section __DWARF,__debug_ranges,regular,debug", true,
683 SectionKind::getMetadata());
684 DwarfMacroInfoSection =
685 getOrCreateSection(".section __DWARF,__debug_macinfo,regular,debug", true,
686 SectionKind::getMetadata());
687 DwarfDebugInlineSection =
688 getOrCreateSection(".section __DWARF,__debug_inlined,regular,debug", true,
689 SectionKind::getMetadata());
692 const MCSection *TargetLoweringObjectFileMachO::
693 SelectSectionForGlobal(const GlobalValue *GV, SectionKind Kind,
694 Mangler *Mang, const TargetMachine &TM) const {
695 assert(!Kind.isThreadLocal() && "Darwin doesn't support TLS");
698 return GV->isWeakForLinker() ? TextCoalSection : TextSection;
700 // If this is weak/linkonce, put this in a coalescable section, either in text
701 // or data depending on if it is writable.
702 if (GV->isWeakForLinker()) {
703 if (Kind.isReadOnly())
704 return ConstTextCoalSection;
705 return DataCoalSection;
708 // FIXME: Alignment check should be handled by section classifier.
709 if (Kind.isMergeable1ByteCString() ||
710 Kind.isMergeable2ByteCString()) {
711 if (TM.getTargetData()->getPreferredAlignment(
712 cast<GlobalVariable>(GV)) < 32) {
713 if (Kind.isMergeable1ByteCString())
714 return CStringSection;
715 assert(Kind.isMergeable2ByteCString());
716 return UStringSection;
720 if (Kind.isMergeableConst()) {
721 if (Kind.isMergeableConst4())
722 return FourByteConstantSection;
723 if (Kind.isMergeableConst8())
724 return EightByteConstantSection;
725 if (Kind.isMergeableConst16() && SixteenByteConstantSection)
726 return SixteenByteConstantSection;
729 // Otherwise, if it is readonly, but not something we can specially optimize,
730 // just drop it in .const.
731 if (Kind.isReadOnly())
732 return ReadOnlySection;
734 // If this is marked const, put it into a const section. But if the dynamic
735 // linker needs to write to it, put it in the data segment.
736 if (Kind.isReadOnlyWithRel())
737 return ConstDataSection;
739 // Otherwise, just drop the variable in the normal data section.
744 TargetLoweringObjectFileMachO::getSectionForConstant(SectionKind Kind) const {
745 // If this constant requires a relocation, we have to put it in the data
746 // segment, not in the text segment.
747 if (Kind.isDataRel())
748 return ConstDataSection;
750 if (Kind.isMergeableConst4())
751 return FourByteConstantSection;
752 if (Kind.isMergeableConst8())
753 return EightByteConstantSection;
754 if (Kind.isMergeableConst16() && SixteenByteConstantSection)
755 return SixteenByteConstantSection;
756 return ReadOnlySection; // .const
759 /// shouldEmitUsedDirectiveFor - This hook allows targets to selectively decide
760 /// not to emit the UsedDirective for some symbols in llvm.used.
761 // FIXME: REMOVE this (rdar://7071300)
762 bool TargetLoweringObjectFileMachO::
763 shouldEmitUsedDirectiveFor(const GlobalValue *GV, Mangler *Mang) const {
764 /// On Darwin, internally linked data beginning with "L" or "l" does not have
765 /// the directive emitted (this occurs in ObjC metadata).
766 if (!GV) return false;
768 // Check whether the mangled name has the "Private" or "LinkerPrivate" prefix.
769 if (GV->hasLocalLinkage() && !isa<Function>(GV)) {
770 // FIXME: ObjC metadata is currently emitted as internal symbols that have
771 // \1L and \0l prefixes on them. Fix them to be Private/LinkerPrivate and
772 // this horrible hack can go away.
773 const std::string &Name = Mang->getMangledName(GV);
774 if (Name[0] == 'L' || Name[0] == 'l')
782 //===----------------------------------------------------------------------===//
784 //===----------------------------------------------------------------------===//
786 const MCSection *TargetLoweringObjectFileCOFF::
787 getCOFFSection(const char *Name, bool isDirective, SectionKind K) {
788 return getOrCreateSection(Name, isDirective, K);
791 void TargetLoweringObjectFileCOFF::Initialize(MCContext &Ctx,
792 const TargetMachine &TM) {
793 TargetLoweringObjectFile::Initialize(Ctx, TM);
794 TextSection = getOrCreateSection("\t.text", true,
795 SectionKind::getText());
796 DataSection = getOrCreateSection("\t.data", true,
797 SectionKind::getDataRel());
799 getOrCreateSection(".ctors", false, SectionKind::getDataRel());
801 getOrCreateSection(".dtors", false, SectionKind::getDataRel());
805 // FIXME: Don't use 'directive' mode here.
807 getOrCreateSection("\t.section\t.debug_abbrev,\"dr\"",
808 true, SectionKind::getMetadata());
810 getOrCreateSection("\t.section\t.debug_info,\"dr\"",
811 true, SectionKind::getMetadata());
813 getOrCreateSection("\t.section\t.debug_line,\"dr\"",
814 true, SectionKind::getMetadata());
816 getOrCreateSection("\t.section\t.debug_frame,\"dr\"",
817 true, SectionKind::getMetadata());
818 DwarfPubNamesSection =
819 getOrCreateSection("\t.section\t.debug_pubnames,\"dr\"",
820 true, SectionKind::getMetadata());
821 DwarfPubTypesSection =
822 getOrCreateSection("\t.section\t.debug_pubtypes,\"dr\"",
823 true, SectionKind::getMetadata());
825 getOrCreateSection("\t.section\t.debug_str,\"dr\"",
826 true, SectionKind::getMetadata());
828 getOrCreateSection("\t.section\t.debug_loc,\"dr\"",
829 true, SectionKind::getMetadata());
830 DwarfARangesSection =
831 getOrCreateSection("\t.section\t.debug_aranges,\"dr\"",
832 true, SectionKind::getMetadata());
834 getOrCreateSection("\t.section\t.debug_ranges,\"dr\"",
835 true, SectionKind::getMetadata());
836 DwarfMacroInfoSection =
837 getOrCreateSection("\t.section\t.debug_macinfo,\"dr\"",
838 true, SectionKind::getMetadata());
841 void TargetLoweringObjectFileCOFF::
842 getSectionFlagsAsString(SectionKind Kind, SmallVectorImpl<char> &Str) const {
843 // FIXME: Inefficient.
844 std::string Res = ",\"";
847 if (Kind.isWriteable())
851 Str.append(Res.begin(), Res.end());
854 static const char *getCOFFSectionPrefixForUniqueGlobal(SectionKind Kind) {
856 return ".text$linkonce";
857 if (Kind.isWriteable())
858 return ".data$linkonce";
859 return ".rdata$linkonce";
863 const MCSection *TargetLoweringObjectFileCOFF::
864 SelectSectionForGlobal(const GlobalValue *GV, SectionKind Kind,
865 Mangler *Mang, const TargetMachine &TM) const {
866 assert(!Kind.isThreadLocal() && "Doesn't support TLS");
868 // If this global is linkonce/weak and the target handles this by emitting it
869 // into a 'uniqued' section name, create and return the section now.
870 if (GV->isWeakForLinker()) {
871 const char *Prefix = getCOFFSectionPrefixForUniqueGlobal(Kind);
872 std::string Name = Mang->makeNameProper(GV->getNameStr());
873 return getOrCreateSection((Prefix+Name).c_str(), false, Kind);
877 return getTextSection();
879 return getDataSection();