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 /// getKindForGlobal - 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 SectionKind TargetLoweringObjectFile::getKindForGlobal(const GlobalValue *GV,
119 const TargetMachine &TM){
120 assert(!GV->isDeclaration() && !GV->hasAvailableExternallyLinkage() &&
121 "Can only be used for global definitions");
123 Reloc::Model ReloModel = TM.getRelocationModel();
125 // Early exit - functions should be always in text sections.
126 const GlobalVariable *GVar = dyn_cast<GlobalVariable>(GV);
128 return SectionKind::getText();
131 // Handle thread-local data first.
132 if (GVar->isThreadLocal()) {
133 if (isSuitableForBSS(GVar))
134 return SectionKind::getThreadBSS();
135 return SectionKind::getThreadData();
138 // Variable can be easily put to BSS section.
139 if (isSuitableForBSS(GVar))
140 return SectionKind::getBSS();
142 Constant *C = GVar->getInitializer();
144 // If the global is marked constant, we can put it into a mergable section,
145 // a mergable string section, or general .data if it contains relocations.
146 if (GVar->isConstant()) {
147 // If the initializer for the global contains something that requires a
148 // relocation, then we may have to drop this into a wriable data section
149 // even though it is marked const.
150 switch (C->getRelocationInfo()) {
151 default: llvm_unreachable("unknown relocation info kind");
152 case Constant::NoRelocation:
153 // If initializer is a null-terminated string, put it in a "cstring"
154 // section of the right width.
155 if (const ArrayType *ATy = dyn_cast<ArrayType>(C->getType())) {
156 if (const IntegerType *ITy =
157 dyn_cast<IntegerType>(ATy->getElementType())) {
158 if ((ITy->getBitWidth() == 8 || ITy->getBitWidth() == 16 ||
159 ITy->getBitWidth() == 32) &&
160 IsNullTerminatedString(C)) {
161 if (ITy->getBitWidth() == 8)
162 return SectionKind::getMergeable1ByteCString();
163 if (ITy->getBitWidth() == 16)
164 return SectionKind::getMergeable2ByteCString();
166 assert(ITy->getBitWidth() == 32 && "Unknown width");
167 return SectionKind::getMergeable4ByteCString();
172 // Otherwise, just drop it into a mergable constant section. If we have
173 // a section for this size, use it, otherwise use the arbitrary sized
175 switch (TM.getTargetData()->getTypeAllocSize(C->getType())) {
176 case 4: return SectionKind::getMergeableConst4();
177 case 8: return SectionKind::getMergeableConst8();
178 case 16: return SectionKind::getMergeableConst16();
179 default: return SectionKind::getMergeableConst();
182 case Constant::LocalRelocation:
183 // In static relocation model, the linker will resolve all addresses, so
184 // the relocation entries will actually be constants by the time the app
185 // starts up. However, we can't put this into a mergable section, because
186 // the linker doesn't take relocations into consideration when it tries to
187 // merge entries in the section.
188 if (ReloModel == Reloc::Static)
189 return SectionKind::getReadOnly();
191 // Otherwise, the dynamic linker needs to fix it up, put it in the
192 // writable data.rel.local section.
193 return SectionKind::getReadOnlyWithRelLocal();
195 case Constant::GlobalRelocations:
196 // In static relocation model, the linker will resolve all addresses, so
197 // the relocation entries will actually be constants by the time the app
198 // starts up. However, we can't put this into a mergable section, because
199 // the linker doesn't take relocations into consideration when it tries to
200 // merge entries in the section.
201 if (ReloModel == Reloc::Static)
202 return SectionKind::getReadOnly();
204 // Otherwise, the dynamic linker needs to fix it up, put it in the
205 // writable data.rel section.
206 return SectionKind::getReadOnlyWithRel();
210 // Okay, this isn't a constant. If the initializer for the global is going
211 // to require a runtime relocation by the dynamic linker, put it into a more
212 // specific section to improve startup time of the app. This coalesces these
213 // globals together onto fewer pages, improving the locality of the dynamic
215 if (ReloModel == Reloc::Static)
216 return SectionKind::getDataNoRel();
218 switch (C->getRelocationInfo()) {
219 default: llvm_unreachable("unknown relocation info kind");
220 case Constant::NoRelocation:
221 return SectionKind::getDataNoRel();
222 case Constant::LocalRelocation:
223 return SectionKind::getDataRelLocal();
224 case Constant::GlobalRelocations:
225 return SectionKind::getDataRel();
229 /// SectionForGlobal - This method computes the appropriate section to emit
230 /// the specified global variable or function definition. This should not
231 /// be passed external (or available externally) globals.
232 const MCSection *TargetLoweringObjectFile::
233 SectionForGlobal(const GlobalValue *GV, SectionKind Kind, Mangler *Mang,
234 const TargetMachine &TM) const {
235 // Select section name.
236 if (GV->hasSection())
237 return getExplicitSectionGlobal(GV, Kind, Mang, TM);
240 // Use default section depending on the 'type' of global
241 return SelectSectionForGlobal(GV, Kind, Mang, TM);
245 // Lame default implementation. Calculate the section name for global.
247 TargetLoweringObjectFile::SelectSectionForGlobal(const GlobalValue *GV,
250 const TargetMachine &TM) const{
251 assert(!Kind.isThreadLocal() && "Doesn't support TLS");
254 return getTextSection();
256 if (Kind.isBSS() && BSSSection != 0)
259 if (Kind.isReadOnly() && ReadOnlySection != 0)
260 return ReadOnlySection;
262 return getDataSection();
265 /// getSectionForConstant - Given a mergable constant with the
266 /// specified size and relocation information, return a section that it
267 /// should be placed in.
269 TargetLoweringObjectFile::getSectionForConstant(SectionKind Kind) const {
270 if (Kind.isReadOnly() && ReadOnlySection != 0)
271 return ReadOnlySection;
278 //===----------------------------------------------------------------------===//
280 //===----------------------------------------------------------------------===//
282 const MCSection *TargetLoweringObjectFileELF::
283 getELFSection(const char *Name, bool isDirective, SectionKind Kind) const {
284 if (MCSection *S = getContext().GetSection(Name))
286 return MCSection::Create(Name, isDirective, Kind, getContext());
289 void TargetLoweringObjectFileELF::Initialize(MCContext &Ctx,
290 const TargetMachine &TM) {
291 TargetLoweringObjectFile::Initialize(Ctx, TM);
293 BSSSection = getELFSection("\t.bss", true, SectionKind::getBSS());
295 // PPC/Linux doesn't support the .bss directive, it needs .section .bss.
296 // FIXME: Does .section .bss work everywhere??
297 // FIXME2: this should just be handle by the section printer. We should get
298 // away from syntactic view of the sections and MCSection should just be a
300 BSSSection = getELFSection("\t.bss", false, SectionKind::getBSS());
303 TextSection = getELFSection("\t.text", true, SectionKind::getText());
304 DataSection = getELFSection("\t.data", true, SectionKind::getDataRel());
306 getELFSection("\t.rodata", false, SectionKind::getReadOnly());
308 getELFSection("\t.tdata", false, SectionKind::getThreadData());
310 TLSBSSSection = getELFSection("\t.tbss", false,
311 SectionKind::getThreadBSS());
313 DataRelSection = getELFSection("\t.data.rel", false,
314 SectionKind::getDataRel());
315 DataRelLocalSection = getELFSection("\t.data.rel.local", false,
316 SectionKind::getDataRelLocal());
317 DataRelROSection = getELFSection("\t.data.rel.ro", false,
318 SectionKind::getReadOnlyWithRel());
319 DataRelROLocalSection =
320 getELFSection("\t.data.rel.ro.local", false,
321 SectionKind::getReadOnlyWithRelLocal());
323 MergeableConst4Section = getELFSection(".rodata.cst4", false,
324 SectionKind::getMergeableConst4());
325 MergeableConst8Section = getELFSection(".rodata.cst8", false,
326 SectionKind::getMergeableConst8());
327 MergeableConst16Section = getELFSection(".rodata.cst16", false,
328 SectionKind::getMergeableConst16());
331 getELFSection(".ctors", false, SectionKind::getDataRel());
333 getELFSection(".dtors", false, SectionKind::getDataRel());
335 // Exception Handling Sections.
337 // FIXME: We're emitting LSDA info into a readonly section on ELF, even though
338 // it contains relocatable pointers. In PIC mode, this is probably a big
339 // runtime hit for C++ apps. Either the contents of the LSDA need to be
340 // adjusted or this should be a data section.
342 getELFSection(".gcc_except_table", false, SectionKind::getReadOnly());
344 getELFSection(".eh_frame", false, SectionKind::getDataRel());
346 // Debug Info Sections.
348 getELFSection(".debug_abbrev", false, SectionKind::getMetadata());
350 getELFSection(".debug_info", false, SectionKind::getMetadata());
352 getELFSection(".debug_line", false, SectionKind::getMetadata());
354 getELFSection(".debug_frame", false, SectionKind::getMetadata());
355 DwarfPubNamesSection =
356 getELFSection(".debug_pubnames", false, SectionKind::getMetadata());
357 DwarfPubTypesSection =
358 getELFSection(".debug_pubtypes", false, SectionKind::getMetadata());
360 getELFSection(".debug_str", false, SectionKind::getMetadata());
362 getELFSection(".debug_loc", false, SectionKind::getMetadata());
363 DwarfARangesSection =
364 getELFSection(".debug_aranges", false, SectionKind::getMetadata());
366 getELFSection(".debug_ranges", false, SectionKind::getMetadata());
367 DwarfMacroInfoSection =
368 getELFSection(".debug_macinfo", false, SectionKind::getMetadata());
373 getELFKindForNamedSection(const char *Name, SectionKind K) {
374 if (Name[0] != '.') return K;
376 // Some lame default implementation based on some magic section names.
377 if (strncmp(Name, ".gnu.linkonce.b.", 16) == 0 ||
378 strncmp(Name, ".llvm.linkonce.b.", 17) == 0 ||
379 strncmp(Name, ".gnu.linkonce.sb.", 17) == 0 ||
380 strncmp(Name, ".llvm.linkonce.sb.", 18) == 0)
381 return SectionKind::getBSS();
383 if (strcmp(Name, ".tdata") == 0 ||
384 strncmp(Name, ".tdata.", 7) == 0 ||
385 strncmp(Name, ".gnu.linkonce.td.", 17) == 0 ||
386 strncmp(Name, ".llvm.linkonce.td.", 18) == 0)
387 return SectionKind::getThreadData();
389 if (strcmp(Name, ".tbss") == 0 ||
390 strncmp(Name, ".tbss.", 6) == 0 ||
391 strncmp(Name, ".gnu.linkonce.tb.", 17) == 0 ||
392 strncmp(Name, ".llvm.linkonce.tb.", 18) == 0)
393 return SectionKind::getThreadBSS();
398 const MCSection *TargetLoweringObjectFileELF::
399 getExplicitSectionGlobal(const GlobalValue *GV, SectionKind Kind,
400 Mangler *Mang, const TargetMachine &TM) const {
401 // Infer section flags from the section name if we can.
402 Kind = getELFKindForNamedSection(GV->getSection().c_str(), Kind);
404 return getELFSection(GV->getSection().c_str(), false, Kind);
409 void TargetLoweringObjectFileELF::
410 getSectionFlagsAsString(SectionKind Kind, SmallVectorImpl<char> &Str) const {
414 if (!Kind.isMetadata())
418 if (Kind.isWriteable())
420 if (Kind.isMergeable1ByteCString() ||
421 Kind.isMergeable2ByteCString() ||
422 Kind.isMergeable4ByteCString() ||
423 Kind.isMergeableConst4() ||
424 Kind.isMergeableConst8() ||
425 Kind.isMergeableConst16())
427 if (Kind.isMergeable1ByteCString() ||
428 Kind.isMergeable2ByteCString() ||
429 Kind.isMergeable4ByteCString())
431 if (Kind.isThreadLocal())
437 // If comment string is '@', e.g. as on ARM - use '%' instead
444 if (Kind.isBSS() || Kind.isThreadBSS())
447 KindStr = "progbits";
449 Str.append(KindStr, KindStr+strlen(KindStr));
451 if (Kind.isMergeable1ByteCString()) {
454 } else if (Kind.isMergeable2ByteCString()) {
457 } else if (Kind.isMergeable4ByteCString()) {
460 } else if (Kind.isMergeableConst4()) {
463 } else if (Kind.isMergeableConst8()) {
466 } else if (Kind.isMergeableConst16()) {
474 static const char *getSectionPrefixForUniqueGlobal(SectionKind Kind) {
475 if (Kind.isText()) return ".gnu.linkonce.t.";
476 if (Kind.isReadOnly()) return ".gnu.linkonce.r.";
478 if (Kind.isThreadData()) return ".gnu.linkonce.td.";
479 if (Kind.isThreadBSS()) return ".gnu.linkonce.tb.";
481 if (Kind.isBSS()) return ".gnu.linkonce.b.";
482 if (Kind.isDataNoRel()) return ".gnu.linkonce.d.";
483 if (Kind.isDataRelLocal()) return ".gnu.linkonce.d.rel.local.";
484 if (Kind.isDataRel()) return ".gnu.linkonce.d.rel.";
485 if (Kind.isReadOnlyWithRelLocal()) return ".gnu.linkonce.d.rel.ro.local.";
487 assert(Kind.isReadOnlyWithRel() && "Unknown section kind");
488 return ".gnu.linkonce.d.rel.ro.";
491 const MCSection *TargetLoweringObjectFileELF::
492 SelectSectionForGlobal(const GlobalValue *GV, SectionKind Kind,
493 Mangler *Mang, const TargetMachine &TM) const {
495 // If this global is linkonce/weak and the target handles this by emitting it
496 // into a 'uniqued' section name, create and return the section now.
497 if (GV->isWeakForLinker()) {
498 const char *Prefix = getSectionPrefixForUniqueGlobal(Kind);
499 std::string Name = Mang->makeNameProper(GV->getNameStr());
500 return getELFSection((Prefix+Name).c_str(), false, Kind);
503 if (Kind.isText()) return TextSection;
505 if (Kind.isMergeable1ByteCString() ||
506 Kind.isMergeable2ByteCString() ||
507 Kind.isMergeable4ByteCString()) {
509 // We also need alignment here.
510 // FIXME: this is getting the alignment of the character, not the
511 // alignment of the global!
513 TM.getTargetData()->getPreferredAlignment(cast<GlobalVariable>(GV));
515 const char *SizeSpec = ".rodata.str1.";
516 if (Kind.isMergeable2ByteCString())
517 SizeSpec = ".rodata.str2.";
518 else if (Kind.isMergeable4ByteCString())
519 SizeSpec = ".rodata.str4.";
521 assert(Kind.isMergeable1ByteCString() && "unknown string width");
524 std::string Name = SizeSpec + utostr(Align);
525 return getELFSection(Name.c_str(), false, Kind);
528 if (Kind.isMergeableConst()) {
529 if (Kind.isMergeableConst4())
530 return MergeableConst4Section;
531 if (Kind.isMergeableConst8())
532 return MergeableConst8Section;
533 if (Kind.isMergeableConst16())
534 return MergeableConst16Section;
535 return ReadOnlySection; // .const
538 if (Kind.isReadOnly()) return ReadOnlySection;
540 if (Kind.isThreadData()) return TLSDataSection;
541 if (Kind.isThreadBSS()) return TLSBSSSection;
543 if (Kind.isBSS()) return BSSSection;
545 if (Kind.isDataNoRel()) return DataSection;
546 if (Kind.isDataRelLocal()) return DataRelLocalSection;
547 if (Kind.isDataRel()) return DataRelSection;
548 if (Kind.isReadOnlyWithRelLocal()) return DataRelROLocalSection;
550 assert(Kind.isReadOnlyWithRel() && "Unknown section kind");
551 return DataRelROSection;
554 /// getSectionForConstant - Given a mergeable constant with the
555 /// specified size and relocation information, return a section that it
556 /// should be placed in.
557 const MCSection *TargetLoweringObjectFileELF::
558 getSectionForConstant(SectionKind Kind) const {
559 if (Kind.isMergeableConst4())
560 return MergeableConst4Section;
561 if (Kind.isMergeableConst8())
562 return MergeableConst8Section;
563 if (Kind.isMergeableConst16())
564 return MergeableConst16Section;
565 if (Kind.isReadOnly())
566 return ReadOnlySection;
568 if (Kind.isReadOnlyWithRelLocal()) return DataRelROLocalSection;
569 assert(Kind.isReadOnlyWithRel() && "Unknown section kind");
570 return DataRelROSection;
573 //===----------------------------------------------------------------------===//
575 //===----------------------------------------------------------------------===//
578 const MCSection *TargetLoweringObjectFileMachO::
579 getMachOSection(const char *Name, bool isDirective, SectionKind Kind) const {
580 if (MCSection *S = getContext().GetSection(Name))
582 return MCSection::Create(Name, isDirective, Kind, getContext());
587 void TargetLoweringObjectFileMachO::Initialize(MCContext &Ctx,
588 const TargetMachine &TM) {
589 TargetLoweringObjectFile::Initialize(Ctx, TM);
590 TextSection = getMachOSection("\t.text", true, SectionKind::getText());
591 DataSection = getMachOSection("\t.data", true, SectionKind::getDataRel());
593 CStringSection = getMachOSection("\t.cstring", true,
594 SectionKind::getMergeable1ByteCString());
595 UStringSection = getMachOSection("__TEXT,__ustring", false,
596 SectionKind::getMergeable2ByteCString());
597 FourByteConstantSection = getMachOSection("\t.literal4\n", true,
598 SectionKind::getMergeableConst4());
599 EightByteConstantSection = getMachOSection("\t.literal8\n", true,
600 SectionKind::getMergeableConst8());
602 // ld_classic doesn't support .literal16 in 32-bit mode, and ld64 falls back
603 // to using it in -static mode.
604 if (TM.getRelocationModel() != Reloc::Static &&
605 TM.getTargetData()->getPointerSize() == 32)
606 SixteenByteConstantSection =
607 getMachOSection("\t.literal16\n", true,
608 SectionKind::getMergeableConst16());
610 SixteenByteConstantSection = 0;
612 ReadOnlySection = getMachOSection("\t.const", true,
613 SectionKind::getReadOnly());
616 getMachOSection("\t__TEXT,__textcoal_nt,coalesced,pure_instructions",
617 false, SectionKind::getText());
618 ConstTextCoalSection = getMachOSection("\t__TEXT,__const_coal,coalesced",
619 false, SectionKind::getText());
620 ConstDataCoalSection = getMachOSection("\t__DATA,__const_coal,coalesced",
621 false, SectionKind::getText());
622 ConstDataSection = getMachOSection("\t.const_data", true,
623 SectionKind::getReadOnlyWithRel());
624 DataCoalSection = getMachOSection("\t__DATA,__datacoal_nt,coalesced",
625 false, SectionKind::getDataRel());
627 if (TM.getRelocationModel() == Reloc::Static) {
629 getMachOSection(".constructor", true, SectionKind::getDataRel());
631 getMachOSection(".destructor", true, SectionKind::getDataRel());
634 getMachOSection(".mod_init_func", true, SectionKind::getDataRel());
636 getMachOSection(".mod_term_func", true, SectionKind::getDataRel());
639 // Exception Handling.
640 LSDASection = getMachOSection("__DATA,__gcc_except_tab", false,
641 SectionKind::getDataRel());
643 getMachOSection("__TEXT,__eh_frame,coalesced,no_toc+strip_static_syms"
644 "+live_support", false, SectionKind::getReadOnly());
646 // Debug Information.
647 // FIXME: Don't use 'directive' syntax: need flags for debug/regular??
648 // FIXME: Need __DWARF segment.
650 getMachOSection(".section __DWARF,__debug_abbrev,regular,debug", true,
651 SectionKind::getMetadata());
653 getMachOSection(".section __DWARF,__debug_info,regular,debug", true,
654 SectionKind::getMetadata());
656 getMachOSection(".section __DWARF,__debug_line,regular,debug", true,
657 SectionKind::getMetadata());
659 getMachOSection(".section __DWARF,__debug_frame,regular,debug", true,
660 SectionKind::getMetadata());
661 DwarfPubNamesSection =
662 getMachOSection(".section __DWARF,__debug_pubnames,regular,debug", true,
663 SectionKind::getMetadata());
664 DwarfPubTypesSection =
665 getMachOSection(".section __DWARF,__debug_pubtypes,regular,debug", true,
666 SectionKind::getMetadata());
668 getMachOSection(".section __DWARF,__debug_str,regular,debug", true,
669 SectionKind::getMetadata());
671 getMachOSection(".section __DWARF,__debug_loc,regular,debug", true,
672 SectionKind::getMetadata());
673 DwarfARangesSection =
674 getMachOSection(".section __DWARF,__debug_aranges,regular,debug", true,
675 SectionKind::getMetadata());
677 getMachOSection(".section __DWARF,__debug_ranges,regular,debug", true,
678 SectionKind::getMetadata());
679 DwarfMacroInfoSection =
680 getMachOSection(".section __DWARF,__debug_macinfo,regular,debug", true,
681 SectionKind::getMetadata());
682 DwarfDebugInlineSection =
683 getMachOSection(".section __DWARF,__debug_inlined,regular,debug", true,
684 SectionKind::getMetadata());
687 const MCSection *TargetLoweringObjectFileMachO::
688 getExplicitSectionGlobal(const GlobalValue *GV, SectionKind Kind,
689 Mangler *Mang, const TargetMachine &TM) const {
690 return getMachOSection(GV->getSection().c_str(), false, Kind);
693 const MCSection *TargetLoweringObjectFileMachO::
694 SelectSectionForGlobal(const GlobalValue *GV, SectionKind Kind,
695 Mangler *Mang, const TargetMachine &TM) const {
696 assert(!Kind.isThreadLocal() && "Darwin doesn't support TLS");
699 return GV->isWeakForLinker() ? TextCoalSection : TextSection;
701 // If this is weak/linkonce, put this in a coalescable section, either in text
702 // or data depending on if it is writable.
703 if (GV->isWeakForLinker()) {
704 if (Kind.isReadOnly())
705 return ConstTextCoalSection;
706 return DataCoalSection;
709 // FIXME: Alignment check should be handled by section classifier.
710 if (Kind.isMergeable1ByteCString() ||
711 Kind.isMergeable2ByteCString()) {
712 if (TM.getTargetData()->getPreferredAlignment(
713 cast<GlobalVariable>(GV)) < 32) {
714 if (Kind.isMergeable1ByteCString())
715 return CStringSection;
716 assert(Kind.isMergeable2ByteCString());
717 return UStringSection;
721 if (Kind.isMergeableConst()) {
722 if (Kind.isMergeableConst4())
723 return FourByteConstantSection;
724 if (Kind.isMergeableConst8())
725 return EightByteConstantSection;
726 if (Kind.isMergeableConst16() && SixteenByteConstantSection)
727 return SixteenByteConstantSection;
730 // Otherwise, if it is readonly, but not something we can specially optimize,
731 // just drop it in .const.
732 if (Kind.isReadOnly())
733 return ReadOnlySection;
735 // If this is marked const, put it into a const section. But if the dynamic
736 // linker needs to write to it, put it in the data segment.
737 if (Kind.isReadOnlyWithRel())
738 return ConstDataSection;
740 // Otherwise, just drop the variable in the normal data section.
745 TargetLoweringObjectFileMachO::getSectionForConstant(SectionKind Kind) const {
746 // If this constant requires a relocation, we have to put it in the data
747 // segment, not in the text segment.
748 if (Kind.isDataRel())
749 return ConstDataSection;
751 if (Kind.isMergeableConst4())
752 return FourByteConstantSection;
753 if (Kind.isMergeableConst8())
754 return EightByteConstantSection;
755 if (Kind.isMergeableConst16() && SixteenByteConstantSection)
756 return SixteenByteConstantSection;
757 return ReadOnlySection; // .const
760 /// shouldEmitUsedDirectiveFor - This hook allows targets to selectively decide
761 /// not to emit the UsedDirective for some symbols in llvm.used.
762 // FIXME: REMOVE this (rdar://7071300)
763 bool TargetLoweringObjectFileMachO::
764 shouldEmitUsedDirectiveFor(const GlobalValue *GV, Mangler *Mang) const {
765 /// On Darwin, internally linked data beginning with "L" or "l" does not have
766 /// the directive emitted (this occurs in ObjC metadata).
767 if (!GV) return false;
769 // Check whether the mangled name has the "Private" or "LinkerPrivate" prefix.
770 if (GV->hasLocalLinkage() && !isa<Function>(GV)) {
771 // FIXME: ObjC metadata is currently emitted as internal symbols that have
772 // \1L and \0l prefixes on them. Fix them to be Private/LinkerPrivate and
773 // this horrible hack can go away.
774 const std::string &Name = Mang->getMangledName(GV);
775 if (Name[0] == 'L' || Name[0] == 'l')
783 //===----------------------------------------------------------------------===//
785 //===----------------------------------------------------------------------===//
788 const MCSection *TargetLoweringObjectFileCOFF::
789 getCOFFSection(const char *Name, bool isDirective, SectionKind Kind) const {
790 if (MCSection *S = getContext().GetSection(Name))
792 return MCSection::Create(Name, isDirective, Kind, getContext());
795 void TargetLoweringObjectFileCOFF::Initialize(MCContext &Ctx,
796 const TargetMachine &TM) {
797 TargetLoweringObjectFile::Initialize(Ctx, TM);
798 TextSection = getCOFFSection("\t.text", true, SectionKind::getText());
799 DataSection = getCOFFSection("\t.data", true, SectionKind::getDataRel());
801 getCOFFSection(".ctors", false, SectionKind::getDataRel());
803 getCOFFSection(".dtors", false, SectionKind::getDataRel());
807 // FIXME: Don't use 'directive' mode here.
809 getCOFFSection("\t.section\t.debug_abbrev,\"dr\"",
810 true, SectionKind::getMetadata());
812 getCOFFSection("\t.section\t.debug_info,\"dr\"",
813 true, SectionKind::getMetadata());
815 getCOFFSection("\t.section\t.debug_line,\"dr\"",
816 true, SectionKind::getMetadata());
818 getCOFFSection("\t.section\t.debug_frame,\"dr\"",
819 true, SectionKind::getMetadata());
820 DwarfPubNamesSection =
821 getCOFFSection("\t.section\t.debug_pubnames,\"dr\"",
822 true, SectionKind::getMetadata());
823 DwarfPubTypesSection =
824 getCOFFSection("\t.section\t.debug_pubtypes,\"dr\"",
825 true, SectionKind::getMetadata());
827 getCOFFSection("\t.section\t.debug_str,\"dr\"",
828 true, SectionKind::getMetadata());
830 getCOFFSection("\t.section\t.debug_loc,\"dr\"",
831 true, SectionKind::getMetadata());
832 DwarfARangesSection =
833 getCOFFSection("\t.section\t.debug_aranges,\"dr\"",
834 true, SectionKind::getMetadata());
836 getCOFFSection("\t.section\t.debug_ranges,\"dr\"",
837 true, SectionKind::getMetadata());
838 DwarfMacroInfoSection =
839 getCOFFSection("\t.section\t.debug_macinfo,\"dr\"",
840 true, SectionKind::getMetadata());
843 const MCSection *TargetLoweringObjectFileCOFF::
844 getExplicitSectionGlobal(const GlobalValue *GV, SectionKind Kind,
845 Mangler *Mang, const TargetMachine &TM) const {
846 return getCOFFSection(GV->getSection().c_str(), false, Kind);
850 void TargetLoweringObjectFileCOFF::
851 getSectionFlagsAsString(SectionKind Kind, SmallVectorImpl<char> &Str) const {
852 // FIXME: Inefficient.
853 std::string Res = ",\"";
856 if (Kind.isWriteable())
860 Str.append(Res.begin(), Res.end());
863 static const char *getCOFFSectionPrefixForUniqueGlobal(SectionKind Kind) {
865 return ".text$linkonce";
866 if (Kind.isWriteable())
867 return ".data$linkonce";
868 return ".rdata$linkonce";
872 const MCSection *TargetLoweringObjectFileCOFF::
873 SelectSectionForGlobal(const GlobalValue *GV, SectionKind Kind,
874 Mangler *Mang, const TargetMachine &TM) const {
875 assert(!Kind.isThreadLocal() && "Doesn't support TLS");
877 // If this global is linkonce/weak and the target handles this by emitting it
878 // into a 'uniqued' section name, create and return the section now.
879 if (GV->isWeakForLinker()) {
880 const char *Prefix = getCOFFSectionPrefixForUniqueGlobal(Kind);
881 std::string Name = Mang->makeNameProper(GV->getNameStr());
882 return getCOFFSection((Prefix+Name).c_str(), false, Kind);
886 return getTextSection();
888 return getDataSection();