Bug Summary

File:lib/MC/MCMachOStreamer.cpp
Location:line 426, column 3
Description:Potential leak of memory pointed to by 'F'

Annotated Source Code

1//===-- MCMachOStreamer.cpp - MachO Streamer ------------------------------===//
2//
3// The LLVM Compiler Infrastructure
4//
5// This file is distributed under the University of Illinois Open Source
6// License. See LICENSE.TXT for details.
7//
8//===----------------------------------------------------------------------===//
9
10#include "llvm/MC/MCStreamer.h"
11#include "llvm/ADT/DenseMap.h"
12#include "llvm/ADT/SmallVector.h"
13#include "llvm/MC/MCAsmBackend.h"
14#include "llvm/MC/MCAssembler.h"
15#include "llvm/MC/MCCodeEmitter.h"
16#include "llvm/MC/MCContext.h"
17#include "llvm/MC/MCDwarf.h"
18#include "llvm/MC/MCExpr.h"
19#include "llvm/MC/MCInst.h"
20#include "llvm/MC/MCLinkerOptimizationHint.h"
21#include "llvm/MC/MCMachOSymbolFlags.h"
22#include "llvm/MC/MCObjectFileInfo.h"
23#include "llvm/MC/MCObjectStreamer.h"
24#include "llvm/MC/MCSection.h"
25#include "llvm/MC/MCSectionMachO.h"
26#include "llvm/MC/MCSymbol.h"
27#include "llvm/Support/Dwarf.h"
28#include "llvm/Support/ErrorHandling.h"
29#include "llvm/Support/TargetRegistry.h"
30#include "llvm/Support/raw_ostream.h"
31
32using namespace llvm;
33
34namespace {
35
36class MCMachOStreamer : public MCObjectStreamer {
37private:
38 /// LabelSections - true if each section change should emit a linker local
39 /// label for use in relocations for assembler local references. Obviates the
40 /// need for local relocations. False by default.
41 bool LabelSections;
42
43 bool DWARFMustBeAtTheEnd;
44 bool CreatedADWARFSection;
45
46 /// HasSectionLabel - map of which sections have already had a non-local
47 /// label emitted to them. Used so we don't emit extraneous linker local
48 /// labels in the middle of the section.
49 DenseMap<const MCSection*, bool> HasSectionLabel;
50
51 void EmitInstToData(const MCInst &Inst, const MCSubtargetInfo &STI) override;
52
53 void EmitDataRegion(DataRegionData::KindTy Kind);
54 void EmitDataRegionEnd();
55
56public:
57 MCMachOStreamer(MCContext &Context, MCAsmBackend &MAB, raw_pwrite_stream &OS,
58 MCCodeEmitter *Emitter, bool DWARFMustBeAtTheEnd, bool label)
59 : MCObjectStreamer(Context, MAB, OS, Emitter), LabelSections(label),
60 DWARFMustBeAtTheEnd(DWARFMustBeAtTheEnd), CreatedADWARFSection(false) {}
61
62 /// state management
63 void reset() override {
64 HasSectionLabel.clear();
65 MCObjectStreamer::reset();
66 }
67
68 /// @name MCStreamer Interface
69 /// @{
70
71 void ChangeSection(MCSection *Sect, const MCExpr *Subsect) override;
72 void EmitLabel(MCSymbol *Symbol) override;
73 void EmitEHSymAttributes(const MCSymbol *Symbol, MCSymbol *EHSymbol) override;
74 void EmitAssemblerFlag(MCAssemblerFlag Flag) override;
75 void EmitLinkerOptions(ArrayRef<std::string> Options) override;
76 void EmitDataRegion(MCDataRegionType Kind) override;
77 void EmitVersionMin(MCVersionMinType Kind, unsigned Major,
78 unsigned Minor, unsigned Update) override;
79 void EmitThumbFunc(MCSymbol *Func) override;
80 bool EmitSymbolAttribute(MCSymbol *Symbol, MCSymbolAttr Attribute) override;
81 void EmitSymbolDesc(MCSymbol *Symbol, unsigned DescValue) override;
82 void EmitCommonSymbol(MCSymbol *Symbol, uint64_t Size,
83 unsigned ByteAlignment) override;
84 void BeginCOFFSymbolDef(const MCSymbol *Symbol) override {
85 llvm_unreachable("macho doesn't support this directive")::llvm::llvm_unreachable_internal("macho doesn't support this directive"
, "/tmp/buildd/llvm-toolchain-snapshot-3.7~svn237945/lib/MC/MCMachOStreamer.cpp"
, 85);
86 }
87 void EmitCOFFSymbolStorageClass(int StorageClass) override {
88 llvm_unreachable("macho doesn't support this directive")::llvm::llvm_unreachable_internal("macho doesn't support this directive"
, "/tmp/buildd/llvm-toolchain-snapshot-3.7~svn237945/lib/MC/MCMachOStreamer.cpp"
, 88);
89 }
90 void EmitCOFFSymbolType(int Type) override {
91 llvm_unreachable("macho doesn't support this directive")::llvm::llvm_unreachable_internal("macho doesn't support this directive"
, "/tmp/buildd/llvm-toolchain-snapshot-3.7~svn237945/lib/MC/MCMachOStreamer.cpp"
, 91);
92 }
93 void EndCOFFSymbolDef() override {
94 llvm_unreachable("macho doesn't support this directive")::llvm::llvm_unreachable_internal("macho doesn't support this directive"
, "/tmp/buildd/llvm-toolchain-snapshot-3.7~svn237945/lib/MC/MCMachOStreamer.cpp"
, 94);
95 }
96 void EmitELFSize(MCSymbol *Symbol, const MCExpr *Value) override {
97 llvm_unreachable("macho doesn't support this directive")::llvm::llvm_unreachable_internal("macho doesn't support this directive"
, "/tmp/buildd/llvm-toolchain-snapshot-3.7~svn237945/lib/MC/MCMachOStreamer.cpp"
, 97);
98 }
99 void EmitLocalCommonSymbol(MCSymbol *Symbol, uint64_t Size,
100 unsigned ByteAlignment) override;
101 void EmitZerofill(MCSection *Section, MCSymbol *Symbol = nullptr,
102 uint64_t Size = 0, unsigned ByteAlignment = 0) override;
103 void EmitTBSSSymbol(MCSection *Section, MCSymbol *Symbol, uint64_t Size,
104 unsigned ByteAlignment = 0) override;
105
106 void EmitFileDirective(StringRef Filename) override {
107 // FIXME: Just ignore the .file; it isn't important enough to fail the
108 // entire assembly.
109
110 // report_fatal_error("unsupported directive: '.file'");
111 }
112
113 void EmitIdent(StringRef IdentString) override {
114 llvm_unreachable("macho doesn't support this directive")::llvm::llvm_unreachable_internal("macho doesn't support this directive"
, "/tmp/buildd/llvm-toolchain-snapshot-3.7~svn237945/lib/MC/MCMachOStreamer.cpp"
, 114);
115 }
116
117 void EmitLOHDirective(MCLOHType Kind, const MCLOHArgs &Args) override {
118 getAssembler().getLOHContainer().addDirective(Kind, Args);
119 }
120
121 void FinishImpl() override;
122};
123
124} // end anonymous namespace.
125
126static bool canGoAfterDWARF(const MCSectionMachO &MSec) {
127 // These sections are created by the assembler itself after the end of
128 // the .s file.
129 StringRef SegName = MSec.getSegmentName();
130 StringRef SecName = MSec.getSectionName();
131
132 if (SegName == "__LD" && SecName == "__compact_unwind")
133 return true;
134
135 if (SegName == "__IMPORT") {
136 if (SecName == "__jump_table")
137 return true;
138
139 if (SecName == "__pointers")
140 return true;
141 }
142
143 if (SegName == "__TEXT" && SecName == "__eh_frame")
144 return true;
145
146 if (SegName == "__DATA" && SecName == "__nl_symbol_ptr")
147 return true;
148
149 return false;
150}
151
152void MCMachOStreamer::ChangeSection(MCSection *Section,
153 const MCExpr *Subsection) {
154 // Change the section normally.
155 bool Created = MCObjectStreamer::changeSectionImpl(Section, Subsection);
156 const MCSectionMachO &MSec = *cast<MCSectionMachO>(Section);
157 StringRef SegName = MSec.getSegmentName();
158 if (SegName == "__DWARF")
159 CreatedADWARFSection = true;
160 else if (Created && DWARFMustBeAtTheEnd && !canGoAfterDWARF(MSec))
161 assert(!CreatedADWARFSection && "Creating regular section after DWARF")((!CreatedADWARFSection && "Creating regular section after DWARF"
) ? static_cast<void> (0) : __assert_fail ("!CreatedADWARFSection && \"Creating regular section after DWARF\""
, "/tmp/buildd/llvm-toolchain-snapshot-3.7~svn237945/lib/MC/MCMachOStreamer.cpp"
, 161, __PRETTY_FUNCTION__));
162
163 // Output a linker-local symbol so we don't need section-relative local
164 // relocations. The linker hates us when we do that.
165 if (LabelSections && !HasSectionLabel[Section]) {
166 MCSymbol *Label = getContext().createLinkerPrivateTempSymbol();
167 EmitLabel(Label);
168 HasSectionLabel[Section] = true;
169 }
170}
171
172void MCMachOStreamer::EmitEHSymAttributes(const MCSymbol *Symbol,
173 MCSymbol *EHSymbol) {
174 MCSymbolData &SD =
175 getAssembler().getOrCreateSymbolData(*Symbol);
176 if (SD.isExternal())
177 EmitSymbolAttribute(EHSymbol, MCSA_Global);
178 if (SD.getFlags() & SF_WeakDefinition)
179 EmitSymbolAttribute(EHSymbol, MCSA_WeakDefinition);
180 if (SD.isPrivateExtern())
181 EmitSymbolAttribute(EHSymbol, MCSA_PrivateExtern);
182}
183
184void MCMachOStreamer::EmitLabel(MCSymbol *Symbol) {
185 assert(Symbol->isUndefined() && "Cannot define a symbol twice!")((Symbol->isUndefined() && "Cannot define a symbol twice!"
) ? static_cast<void> (0) : __assert_fail ("Symbol->isUndefined() && \"Cannot define a symbol twice!\""
, "/tmp/buildd/llvm-toolchain-snapshot-3.7~svn237945/lib/MC/MCMachOStreamer.cpp"
, 185, __PRETTY_FUNCTION__));
186
187 // isSymbolLinkerVisible uses the section.
188 AssignSection(Symbol, getCurrentSection().first);
189 // We have to create a new fragment if this is an atom defining symbol,
190 // fragments cannot span atoms.
191 if (getAssembler().isSymbolLinkerVisible(*Symbol))
192 insert(new MCDataFragment());
193
194 MCObjectStreamer::EmitLabel(Symbol);
195
196 MCSymbolData &SD = getAssembler().getSymbolData(*Symbol);
197 // This causes the reference type flag to be cleared. Darwin 'as' was "trying"
198 // to clear the weak reference and weak definition bits too, but the
199 // implementation was buggy. For now we just try to match 'as', for
200 // diffability.
201 //
202 // FIXME: Cleanup this code, these bits should be emitted based on semantic
203 // properties, not on the order of definition, etc.
204 SD.setFlags(SD.getFlags() & ~SF_ReferenceTypeMask);
205}
206
207void MCMachOStreamer::EmitDataRegion(DataRegionData::KindTy Kind) {
208 if (!getAssembler().getBackend().hasDataInCodeSupport())
209 return;
210 // Create a temporary label to mark the start of the data region.
211 MCSymbol *Start = getContext().createTempSymbol();
212 EmitLabel(Start);
213 // Record the region for the object writer to use.
214 DataRegionData Data = { Kind, Start, nullptr };
215 std::vector<DataRegionData> &Regions = getAssembler().getDataRegions();
216 Regions.push_back(Data);
217}
218
219void MCMachOStreamer::EmitDataRegionEnd() {
220 if (!getAssembler().getBackend().hasDataInCodeSupport())
221 return;
222 std::vector<DataRegionData> &Regions = getAssembler().getDataRegions();
223 assert(!Regions.empty() && "Mismatched .end_data_region!")((!Regions.empty() && "Mismatched .end_data_region!")
? static_cast<void> (0) : __assert_fail ("!Regions.empty() && \"Mismatched .end_data_region!\""
, "/tmp/buildd/llvm-toolchain-snapshot-3.7~svn237945/lib/MC/MCMachOStreamer.cpp"
, 223, __PRETTY_FUNCTION__));
224 DataRegionData &Data = Regions.back();
225 assert(!Data.End && "Mismatched .end_data_region!")((!Data.End && "Mismatched .end_data_region!") ? static_cast
<void> (0) : __assert_fail ("!Data.End && \"Mismatched .end_data_region!\""
, "/tmp/buildd/llvm-toolchain-snapshot-3.7~svn237945/lib/MC/MCMachOStreamer.cpp"
, 225, __PRETTY_FUNCTION__));
226 // Create a temporary label to mark the end of the data region.
227 Data.End = getContext().createTempSymbol();
228 EmitLabel(Data.End);
229}
230
231void MCMachOStreamer::EmitAssemblerFlag(MCAssemblerFlag Flag) {
232 // Let the target do whatever target specific stuff it needs to do.
233 getAssembler().getBackend().handleAssemblerFlag(Flag);
234 // Do any generic stuff we need to do.
235 switch (Flag) {
236 case MCAF_SyntaxUnified: return; // no-op here.
237 case MCAF_Code16: return; // Change parsing mode; no-op here.
238 case MCAF_Code32: return; // Change parsing mode; no-op here.
239 case MCAF_Code64: return; // Change parsing mode; no-op here.
240 case MCAF_SubsectionsViaSymbols:
241 getAssembler().setSubsectionsViaSymbols(true);
242 return;
243 }
244}
245
246void MCMachOStreamer::EmitLinkerOptions(ArrayRef<std::string> Options) {
247 getAssembler().getLinkerOptions().push_back(Options);
248}
249
250void MCMachOStreamer::EmitDataRegion(MCDataRegionType Kind) {
251 switch (Kind) {
252 case MCDR_DataRegion:
253 EmitDataRegion(DataRegionData::Data);
254 return;
255 case MCDR_DataRegionJT8:
256 EmitDataRegion(DataRegionData::JumpTable8);
257 return;
258 case MCDR_DataRegionJT16:
259 EmitDataRegion(DataRegionData::JumpTable16);
260 return;
261 case MCDR_DataRegionJT32:
262 EmitDataRegion(DataRegionData::JumpTable32);
263 return;
264 case MCDR_DataRegionEnd:
265 EmitDataRegionEnd();
266 return;
267 }
268}
269
270void MCMachOStreamer::EmitVersionMin(MCVersionMinType Kind, unsigned Major,
271 unsigned Minor, unsigned Update) {
272 getAssembler().setVersionMinInfo(Kind, Major, Minor, Update);
273}
274
275void MCMachOStreamer::EmitThumbFunc(MCSymbol *Symbol) {
276 // Remember that the function is a thumb function. Fixup and relocation
277 // values will need adjusted.
278 getAssembler().setIsThumbFunc(Symbol);
279}
280
281bool MCMachOStreamer::EmitSymbolAttribute(MCSymbol *Symbol,
282 MCSymbolAttr Attribute) {
283 // Indirect symbols are handled differently, to match how 'as' handles
284 // them. This makes writing matching .o files easier.
285 if (Attribute == MCSA_IndirectSymbol) {
286 // Note that we intentionally cannot use the symbol data here; this is
287 // important for matching the string table that 'as' generates.
288 IndirectSymbolData ISD;
289 ISD.Symbol = Symbol;
290 ISD.SectionData = getCurrentSectionData();
291 getAssembler().getIndirectSymbols().push_back(ISD);
292 return true;
293 }
294
295 // Adding a symbol attribute always introduces the symbol, note that an
296 // important side effect of calling getOrCreateSymbolData here is to register
297 // the symbol with the assembler.
298 MCSymbolData &SD = getAssembler().getOrCreateSymbolData(*Symbol);
299
300 // The implementation of symbol attributes is designed to match 'as', but it
301 // leaves much to desired. It doesn't really make sense to arbitrarily add and
302 // remove flags, but 'as' allows this (in particular, see .desc).
303 //
304 // In the future it might be worth trying to make these operations more well
305 // defined.
306 switch (Attribute) {
307 case MCSA_Invalid:
308 case MCSA_ELF_TypeFunction:
309 case MCSA_ELF_TypeIndFunction:
310 case MCSA_ELF_TypeObject:
311 case MCSA_ELF_TypeTLS:
312 case MCSA_ELF_TypeCommon:
313 case MCSA_ELF_TypeNoType:
314 case MCSA_ELF_TypeGnuUniqueObject:
315 case MCSA_Hidden:
316 case MCSA_IndirectSymbol:
317 case MCSA_Internal:
318 case MCSA_Protected:
319 case MCSA_Weak:
320 case MCSA_Local:
321 return false;
322
323 case MCSA_Global:
324 SD.setExternal(true);
325 // This effectively clears the undefined lazy bit, in Darwin 'as', although
326 // it isn't very consistent because it implements this as part of symbol
327 // lookup.
328 //
329 // FIXME: Cleanup this code, these bits should be emitted based on semantic
330 // properties, not on the order of definition, etc.
331 SD.setFlags(SD.getFlags() & ~SF_ReferenceTypeUndefinedLazy);
332 break;
333
334 case MCSA_LazyReference:
335 // FIXME: This requires -dynamic.
336 SD.setFlags(SD.getFlags() | SF_NoDeadStrip);
337 if (Symbol->isUndefined())
338 SD.setFlags(SD.getFlags() | SF_ReferenceTypeUndefinedLazy);
339 break;
340
341 // Since .reference sets the no dead strip bit, it is equivalent to
342 // .no_dead_strip in practice.
343 case MCSA_Reference:
344 case MCSA_NoDeadStrip:
345 SD.setFlags(SD.getFlags() | SF_NoDeadStrip);
346 break;
347
348 case MCSA_SymbolResolver:
349 SD.setFlags(SD.getFlags() | SF_SymbolResolver);
350 break;
351
352 case MCSA_PrivateExtern:
353 SD.setExternal(true);
354 SD.setPrivateExtern(true);
355 break;
356
357 case MCSA_WeakReference:
358 // FIXME: This requires -dynamic.
359 if (Symbol->isUndefined())
360 SD.setFlags(SD.getFlags() | SF_WeakReference);
361 break;
362
363 case MCSA_WeakDefinition:
364 // FIXME: 'as' enforces that this is defined and global. The manual claims
365 // it has to be in a coalesced section, but this isn't enforced.
366 SD.setFlags(SD.getFlags() | SF_WeakDefinition);
367 break;
368
369 case MCSA_WeakDefAutoPrivate:
370 SD.setFlags(SD.getFlags() | SF_WeakDefinition | SF_WeakReference);
371 break;
372 }
373
374 return true;
375}
376
377void MCMachOStreamer::EmitSymbolDesc(MCSymbol *Symbol, unsigned DescValue) {
378 // Encode the 'desc' value into the lowest implementation defined bits.
379 assert(DescValue == (DescValue & SF_DescFlagsMask) &&((DescValue == (DescValue & SF_DescFlagsMask) && "Invalid .desc value!"
) ? static_cast<void> (0) : __assert_fail ("DescValue == (DescValue & SF_DescFlagsMask) && \"Invalid .desc value!\""
, "/tmp/buildd/llvm-toolchain-snapshot-3.7~svn237945/lib/MC/MCMachOStreamer.cpp"
, 380, __PRETTY_FUNCTION__))
380 "Invalid .desc value!")((DescValue == (DescValue & SF_DescFlagsMask) && "Invalid .desc value!"
) ? static_cast<void> (0) : __assert_fail ("DescValue == (DescValue & SF_DescFlagsMask) && \"Invalid .desc value!\""
, "/tmp/buildd/llvm-toolchain-snapshot-3.7~svn237945/lib/MC/MCMachOStreamer.cpp"
, 380, __PRETTY_FUNCTION__));
381 getAssembler().getOrCreateSymbolData(*Symbol).setFlags(
382 DescValue & SF_DescFlagsMask);
383}
384
385void MCMachOStreamer::EmitCommonSymbol(MCSymbol *Symbol, uint64_t Size,
386 unsigned ByteAlignment) {
387 // FIXME: Darwin 'as' does appear to allow redef of a .comm by itself.
388 assert(Symbol->isUndefined() && "Cannot define a symbol twice!")((Symbol->isUndefined() && "Cannot define a symbol twice!"
) ? static_cast<void> (0) : __assert_fail ("Symbol->isUndefined() && \"Cannot define a symbol twice!\""
, "/tmp/buildd/llvm-toolchain-snapshot-3.7~svn237945/lib/MC/MCMachOStreamer.cpp"
, 388, __PRETTY_FUNCTION__));
389
390 AssignSection(Symbol, nullptr);
391
392 MCSymbolData &SD = getAssembler().getOrCreateSymbolData(*Symbol);
393 SD.setExternal(true);
394 SD.setCommon(Size, ByteAlignment);
395}
396
397void MCMachOStreamer::EmitLocalCommonSymbol(MCSymbol *Symbol, uint64_t Size,
398 unsigned ByteAlignment) {
399 // '.lcomm' is equivalent to '.zerofill'.
400 return EmitZerofill(getContext().getObjectFileInfo()->getDataBSSSection(),
401 Symbol, Size, ByteAlignment);
402}
403
404void MCMachOStreamer::EmitZerofill(MCSection *Section, MCSymbol *Symbol,
405 uint64_t Size, unsigned ByteAlignment) {
406 MCSectionData &SectData = getAssembler().getOrCreateSectionData(*Section);
407
408 // The symbol may not be present, which only creates the section.
409 if (!Symbol)
2
←
Assuming 'Symbol' is non-null
→
3
←
Taking false branch
→
410 return;
411
412 // On darwin all virtual sections have zerofill type.
413 assert(Section->isVirtualSection() && "Section does not have zerofill type!")((Section->isVirtualSection() && "Section does not have zerofill type!"
) ? static_cast<void> (0) : __assert_fail ("Section->isVirtualSection() && \"Section does not have zerofill type!\""
, "/tmp/buildd/llvm-toolchain-snapshot-3.7~svn237945/lib/MC/MCMachOStreamer.cpp"
, 413, __PRETTY_FUNCTION__));
414
415 assert(Symbol->isUndefined() && "Cannot define a symbol twice!")((Symbol->isUndefined() && "Cannot define a symbol twice!"
) ? static_cast<void> (0) : __assert_fail ("Symbol->isUndefined() && \"Cannot define a symbol twice!\""
, "/tmp/buildd/llvm-toolchain-snapshot-3.7~svn237945/lib/MC/MCMachOStreamer.cpp"
, 415, __PRETTY_FUNCTION__));
416
417 MCSymbolData &SD = getAssembler().getOrCreateSymbolData(*Symbol);
418
419 // Emit an align fragment if necessary.
420 if (ByteAlignment != 1)
4
←
Assuming 'ByteAlignment' is equal to 1
→
5
←
Taking false branch
→
421 new MCAlignFragment(ByteAlignment, 0, 0, ByteAlignment, &SectData);
422
423 MCFragment *F = new MCFillFragment(0, 0, Size, &SectData);
6
←
Memory is allocated
→
424 SD.setFragment(F);
425
426 AssignSection(Symbol, Section);
7
←
Potential leak of memory pointed to by 'F'
427
428 // Update the maximum alignment on the zero fill section if necessary.
429 if (ByteAlignment > SectData.getAlignment())
430 SectData.setAlignment(ByteAlignment);
431}
432
433// This should always be called with the thread local bss section. Like the
434// .zerofill directive this doesn't actually switch sections on us.
435void MCMachOStreamer::EmitTBSSSymbol(MCSection *Section, MCSymbol *Symbol,
436 uint64_t Size, unsigned ByteAlignment) {
437 EmitZerofill(Section, Symbol, Size, ByteAlignment);
1
Calling 'MCMachOStreamer::EmitZerofill'
→
438 return;
439}
440
441void MCMachOStreamer::EmitInstToData(const MCInst &Inst,
442 const MCSubtargetInfo &STI) {
443 MCDataFragment *DF = getOrCreateDataFragment();
444
445 SmallVector<MCFixup, 4> Fixups;
446 SmallString<256> Code;
447 raw_svector_ostream VecOS(Code);
448 getAssembler().getEmitter().encodeInstruction(Inst, VecOS, Fixups, STI);
449 VecOS.flush();
450
451 // Add the fixups and data.
452 for (unsigned i = 0, e = Fixups.size(); i != e; ++i) {
453 Fixups[i].setOffset(Fixups[i].getOffset() + DF->getContents().size());
454 DF->getFixups().push_back(Fixups[i]);
455 }
456 DF->getContents().append(Code.begin(), Code.end());
457}
458
459void MCMachOStreamer::FinishImpl() {
460 EmitFrames(&getAssembler().getBackend());
461
462 // We have to set the fragment atom associations so we can relax properly for
463 // Mach-O.
464
465 // First, scan the symbol table to build a lookup table from fragments to
466 // defining symbols.
467 DenseMap<const MCFragment *, const MCSymbol *> DefiningSymbolMap;
468 for (const MCSymbol &Symbol : getAssembler().symbols()) {
469 MCSymbolData &SD = Symbol.getData();
470 if (getAssembler().isSymbolLinkerVisible(Symbol) && SD.getFragment()) {
471 // An atom defining symbol should never be internal to a fragment.
472 assert(SD.getOffset() == 0 && "Invalid offset in atom defining symbol!")((SD.getOffset() == 0 && "Invalid offset in atom defining symbol!"
) ? static_cast<void> (0) : __assert_fail ("SD.getOffset() == 0 && \"Invalid offset in atom defining symbol!\""
, "/tmp/buildd/llvm-toolchain-snapshot-3.7~svn237945/lib/MC/MCMachOStreamer.cpp"
, 472, __PRETTY_FUNCTION__));
473 DefiningSymbolMap[SD.getFragment()] = &Symbol;
474 }
475 }
476
477 // Set the fragment atom associations by tracking the last seen atom defining
478 // symbol.
479 for (MCAssembler::iterator it = getAssembler().begin(),
480 ie = getAssembler().end(); it != ie; ++it) {
481 const MCSymbol *CurrentAtom = nullptr;
482 for (MCSectionData::iterator it2 = it->begin(),
483 ie2 = it->end(); it2 != ie2; ++it2) {
484 if (const MCSymbol *Symbol = DefiningSymbolMap.lookup(it2))
485 CurrentAtom = Symbol;
486 it2->setAtom(CurrentAtom);
487 }
488 }
489
490 this->MCObjectStreamer::FinishImpl();
491}
492
493MCStreamer *llvm::createMachOStreamer(MCContext &Context, MCAsmBackend &MAB,
494 raw_pwrite_stream &OS, MCCodeEmitter *CE,
495 bool RelaxAll, bool DWARFMustBeAtTheEnd,
496 bool LabelSections) {
497 MCMachOStreamer *S = new MCMachOStreamer(Context, MAB, OS, CE,
498 DWARFMustBeAtTheEnd, LabelSections);
499 if (RelaxAll)
500 S->getAssembler().setRelaxAll(true);
501 return S;
502}