1 //===- lib/MC/MCELFStreamer.cpp - ELF Object Output -----------------------===//
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 assembles .s files and emits ELF .o object files.
12 //===----------------------------------------------------------------------===//
14 #include "llvm/MC/MCELFStreamer.h"
15 #include "llvm/ADT/STLExtras.h"
16 #include "llvm/ADT/SmallPtrSet.h"
17 #include "llvm/MC/MCAsmBackend.h"
18 #include "llvm/MC/MCAsmLayout.h"
19 #include "llvm/MC/MCAsmInfo.h"
20 #include "llvm/MC/MCAssembler.h"
21 #include "llvm/MC/MCCodeEmitter.h"
22 #include "llvm/MC/MCContext.h"
23 #include "llvm/MC/MCELF.h"
24 #include "llvm/MC/MCELFSymbolFlags.h"
25 #include "llvm/MC/MCExpr.h"
26 #include "llvm/MC/MCInst.h"
27 #include "llvm/MC/MCObjectFileInfo.h"
28 #include "llvm/MC/MCObjectStreamer.h"
29 #include "llvm/MC/MCSection.h"
30 #include "llvm/MC/MCSectionELF.h"
31 #include "llvm/MC/MCSymbol.h"
32 #include "llvm/MC/MCValue.h"
33 #include "llvm/Support/Debug.h"
34 #include "llvm/Support/ELF.h"
35 #include "llvm/Support/ErrorHandling.h"
36 #include "llvm/Support/TargetRegistry.h"
37 #include "llvm/Support/raw_ostream.h"
41 bool MCELFStreamer::isBundleLocked() const {
42 return getCurrentSectionOnly()->isBundleLocked();
45 MCELFStreamer::~MCELFStreamer() {
48 void MCELFStreamer::mergeFragment(MCDataFragment *DF,
49 MCEncodedFragmentWithFixups *EF) {
50 MCAssembler &Assembler = getAssembler();
52 if (Assembler.isBundlingEnabled() && Assembler.getRelaxAll()) {
53 uint64_t FSize = EF->getContents().size();
55 if (FSize > Assembler.getBundleAlignSize())
56 report_fatal_error("Fragment can't be larger than a bundle size");
58 uint64_t RequiredBundlePadding = computeBundlePadding(
59 Assembler, EF, DF->getContents().size(), FSize);
61 if (RequiredBundlePadding > UINT8_MAX)
62 report_fatal_error("Padding cannot exceed 255 bytes");
64 if (RequiredBundlePadding > 0) {
65 SmallString<256> Code;
66 raw_svector_ostream VecOS(Code);
67 MCObjectWriter *OW = Assembler.getBackend().createObjectWriter(VecOS);
69 EF->setBundlePadding(static_cast<uint8_t>(RequiredBundlePadding));
71 Assembler.writeFragmentPadding(*EF, FSize, OW);
75 DF->getContents().append(Code.begin(), Code.end());
79 flushPendingLabels(DF, DF->getContents().size());
81 for (unsigned i = 0, e = EF->getFixups().size(); i != e; ++i) {
82 EF->getFixups()[i].setOffset(EF->getFixups()[i].getOffset() +
83 DF->getContents().size());
84 DF->getFixups().push_back(EF->getFixups()[i]);
86 DF->setHasInstructions(true);
87 DF->getContents().append(EF->getContents().begin(), EF->getContents().end());
90 void MCELFStreamer::InitSections(bool NoExecStack) {
91 // This emulates the same behavior of GNU as. This makes it easier
92 // to compare the output as the major sections are in the same order.
93 MCContext &Ctx = getContext();
94 SwitchSection(Ctx.getObjectFileInfo()->getTextSection());
97 SwitchSection(Ctx.getObjectFileInfo()->getDataSection());
100 SwitchSection(Ctx.getObjectFileInfo()->getBSSSection());
101 EmitCodeAlignment(4);
103 SwitchSection(Ctx.getObjectFileInfo()->getTextSection());
106 SwitchSection(Ctx.getAsmInfo()->getNonexecutableStackSection(Ctx));
109 void MCELFStreamer::EmitLabel(MCSymbol *Symbol) {
110 assert(Symbol->isUndefined() && "Cannot define a symbol twice!");
112 MCObjectStreamer::EmitLabel(Symbol);
114 const MCSectionELF &Section =
115 static_cast<const MCSectionELF&>(Symbol->getSection());
116 MCSymbolData &SD = Symbol->getData();
117 if (Section.getFlags() & ELF::SHF_TLS)
118 MCELF::SetType(SD, ELF::STT_TLS);
121 void MCELFStreamer::EmitAssemblerFlag(MCAssemblerFlag Flag) {
122 // Let the target do whatever target specific stuff it needs to do.
123 getAssembler().getBackend().handleAssemblerFlag(Flag);
124 // Do any generic stuff we need to do.
126 case MCAF_SyntaxUnified: return; // no-op here.
127 case MCAF_Code16: return; // Change parsing mode; no-op here.
128 case MCAF_Code32: return; // Change parsing mode; no-op here.
129 case MCAF_Code64: return; // Change parsing mode; no-op here.
130 case MCAF_SubsectionsViaSymbols:
131 getAssembler().setSubsectionsViaSymbols(true);
135 llvm_unreachable("invalid assembler flag!");
138 // If bundle aligment is used and there are any instructions in the section, it
139 // needs to be aligned to at least the bundle size.
140 static void setSectionAlignmentForBundling(const MCAssembler &Assembler,
141 MCSection *Section) {
142 if (Section && Assembler.isBundlingEnabled() && Section->hasInstructions() &&
143 Section->getAlignment() < Assembler.getBundleAlignSize())
144 Section->setAlignment(Assembler.getBundleAlignSize());
147 void MCELFStreamer::ChangeSection(MCSection *Section,
148 const MCExpr *Subsection) {
149 MCSection *CurSection = getCurrentSectionOnly();
150 if (CurSection && isBundleLocked())
151 report_fatal_error("Unterminated .bundle_lock when changing a section");
153 MCAssembler &Asm = getAssembler();
154 // Ensure the previous section gets aligned if necessary.
155 setSectionAlignmentForBundling(Asm, CurSection);
156 auto *SectionELF = static_cast<const MCSectionELF *>(Section);
157 const MCSymbol *Grp = SectionELF->getGroup();
159 Asm.getOrCreateSymbolData(*Grp);
161 this->MCObjectStreamer::ChangeSection(Section, Subsection);
162 MCContext &Ctx = getContext();
163 MCSymbol *Begin = Section->getBeginSymbol();
165 Begin = Ctx.getOrCreateSectionSymbol(*SectionELF);
166 Section->setBeginSymbol(Begin);
168 if (Begin->isUndefined())
169 MCELF::SetType(Asm.getOrCreateSymbolData(*Begin), ELF::STT_SECTION);
172 void MCELFStreamer::EmitWeakReference(MCSymbol *Alias, const MCSymbol *Symbol) {
173 getAssembler().getOrCreateSymbolData(*Symbol);
174 const MCExpr *Value = MCSymbolRefExpr::Create(
175 Symbol, MCSymbolRefExpr::VK_WEAKREF, getContext());
176 Alias->setVariableValue(Value);
179 // When GNU as encounters more than one .type declaration for an object it seems
180 // to use a mechanism similar to the one below to decide which type is actually
181 // used in the object file. The greater of T1 and T2 is selected based on the
182 // following ordering:
183 // STT_NOTYPE < STT_OBJECT < STT_FUNC < STT_GNU_IFUNC < STT_TLS < anything else
184 // If neither T1 < T2 nor T2 < T1 according to this ordering, use T2 (the user
186 static unsigned CombineSymbolTypes(unsigned T1, unsigned T2) {
187 for (unsigned Type : {ELF::STT_NOTYPE, ELF::STT_OBJECT, ELF::STT_FUNC,
188 ELF::STT_GNU_IFUNC, ELF::STT_TLS}) {
198 bool MCELFStreamer::EmitSymbolAttribute(MCSymbol *Symbol,
199 MCSymbolAttr Attribute) {
200 // Indirect symbols are handled differently, to match how 'as' handles
201 // them. This makes writing matching .o files easier.
202 if (Attribute == MCSA_IndirectSymbol) {
203 // Note that we intentionally cannot use the symbol data here; this is
204 // important for matching the string table that 'as' generates.
205 IndirectSymbolData ISD;
207 ISD.Section = getCurrentSectionOnly();
208 getAssembler().getIndirectSymbols().push_back(ISD);
212 // Adding a symbol attribute always introduces the symbol, note that an
213 // important side effect of calling getOrCreateSymbolData here is to register
214 // the symbol with the assembler.
215 MCSymbolData &SD = getAssembler().getOrCreateSymbolData(*Symbol);
217 // The implementation of symbol attributes is designed to match 'as', but it
218 // leaves much to desired. It doesn't really make sense to arbitrarily add and
219 // remove flags, but 'as' allows this (in particular, see .desc).
221 // In the future it might be worth trying to make these operations more well
224 case MCSA_LazyReference:
226 case MCSA_SymbolResolver:
227 case MCSA_PrivateExtern:
228 case MCSA_WeakDefinition:
229 case MCSA_WeakDefAutoPrivate:
231 case MCSA_IndirectSymbol:
234 case MCSA_NoDeadStrip:
238 case MCSA_ELF_TypeGnuUniqueObject:
239 MCELF::SetType(SD, CombineSymbolTypes(MCELF::GetType(SD), ELF::STT_OBJECT));
240 MCELF::SetBinding(SD, ELF::STB_GNU_UNIQUE);
241 SD.setExternal(true);
242 BindingExplicitlySet.insert(Symbol);
246 MCELF::SetBinding(SD, ELF::STB_GLOBAL);
247 SD.setExternal(true);
248 BindingExplicitlySet.insert(Symbol);
251 case MCSA_WeakReference:
253 MCELF::SetBinding(SD, ELF::STB_WEAK);
254 SD.setExternal(true);
255 BindingExplicitlySet.insert(Symbol);
259 MCELF::SetBinding(SD, ELF::STB_LOCAL);
260 SD.setExternal(false);
261 BindingExplicitlySet.insert(Symbol);
264 case MCSA_ELF_TypeFunction:
265 MCELF::SetType(SD, CombineSymbolTypes(MCELF::GetType(SD),
269 case MCSA_ELF_TypeIndFunction:
270 MCELF::SetType(SD, CombineSymbolTypes(MCELF::GetType(SD),
271 ELF::STT_GNU_IFUNC));
274 case MCSA_ELF_TypeObject:
275 MCELF::SetType(SD, CombineSymbolTypes(MCELF::GetType(SD),
279 case MCSA_ELF_TypeTLS:
280 MCELF::SetType(SD, CombineSymbolTypes(MCELF::GetType(SD),
284 case MCSA_ELF_TypeCommon:
285 // TODO: Emit these as a common symbol.
286 MCELF::SetType(SD, CombineSymbolTypes(MCELF::GetType(SD),
290 case MCSA_ELF_TypeNoType:
291 MCELF::SetType(SD, CombineSymbolTypes(MCELF::GetType(SD),
296 MCELF::SetVisibility(SD, ELF::STV_PROTECTED);
300 MCELF::SetVisibility(SD, ELF::STV_HIDDEN);
304 MCELF::SetVisibility(SD, ELF::STV_INTERNAL);
311 void MCELFStreamer::EmitCommonSymbol(MCSymbol *Symbol, uint64_t Size,
312 unsigned ByteAlignment) {
313 MCSymbolData &SD = getAssembler().getOrCreateSymbolData(*Symbol);
315 if (!BindingExplicitlySet.count(Symbol)) {
316 MCELF::SetBinding(SD, ELF::STB_GLOBAL);
317 SD.setExternal(true);
320 MCELF::SetType(SD, ELF::STT_OBJECT);
322 if (MCELF::GetBinding(SD) == ELF_STB_Local) {
323 MCSection *Section = getAssembler().getContext().getELFSection(
324 ".bss", ELF::SHT_NOBITS, ELF::SHF_WRITE | ELF::SHF_ALLOC);
326 AssignSection(Symbol, Section);
328 struct LocalCommon L = {Symbol, Size, ByteAlignment};
329 LocalCommons.push_back(L);
331 Symbol->setCommon(Size, ByteAlignment);
334 Symbol->setSize(MCConstantExpr::Create(Size, getContext()));
337 void MCELFStreamer::EmitELFSize(MCSymbol *Symbol, const MCExpr *Value) {
338 Symbol->setSize(Value);
341 void MCELFStreamer::EmitLocalCommonSymbol(MCSymbol *Symbol, uint64_t Size,
342 unsigned ByteAlignment) {
343 // FIXME: Should this be caught and done earlier?
344 MCSymbolData &SD = getAssembler().getOrCreateSymbolData(*Symbol);
345 MCELF::SetBinding(SD, ELF::STB_LOCAL);
346 SD.setExternal(false);
347 BindingExplicitlySet.insert(Symbol);
348 EmitCommonSymbol(Symbol, Size, ByteAlignment);
351 void MCELFStreamer::EmitValueImpl(const MCExpr *Value, unsigned Size,
353 if (isBundleLocked())
354 report_fatal_error("Emitting values inside a locked bundle is forbidden");
355 fixSymbolsInTLSFixups(Value);
356 MCObjectStreamer::EmitValueImpl(Value, Size, Loc);
359 void MCELFStreamer::EmitValueToAlignment(unsigned ByteAlignment,
362 unsigned MaxBytesToEmit) {
363 if (isBundleLocked())
364 report_fatal_error("Emitting values inside a locked bundle is forbidden");
365 MCObjectStreamer::EmitValueToAlignment(ByteAlignment, Value,
366 ValueSize, MaxBytesToEmit);
369 // Add a symbol for the file name of this module. They start after the
370 // null symbol and don't count as normal symbol, i.e. a non-STT_FILE symbol
371 // with the same name may appear.
372 void MCELFStreamer::EmitFileDirective(StringRef Filename) {
373 getAssembler().addFileName(Filename);
376 void MCELFStreamer::EmitIdent(StringRef IdentString) {
377 MCSection *Comment = getAssembler().getContext().getELFSection(
378 ".comment", ELF::SHT_PROGBITS, ELF::SHF_MERGE | ELF::SHF_STRINGS, 1, "");
380 SwitchSection(Comment);
385 EmitBytes(IdentString);
390 void MCELFStreamer::fixSymbolsInTLSFixups(const MCExpr *expr) {
391 switch (expr->getKind()) {
393 cast<MCTargetExpr>(expr)->fixELFSymbolsInTLSFixups(getAssembler());
395 case MCExpr::Constant:
398 case MCExpr::Binary: {
399 const MCBinaryExpr *be = cast<MCBinaryExpr>(expr);
400 fixSymbolsInTLSFixups(be->getLHS());
401 fixSymbolsInTLSFixups(be->getRHS());
405 case MCExpr::SymbolRef: {
406 const MCSymbolRefExpr &symRef = *cast<MCSymbolRefExpr>(expr);
407 switch (symRef.getKind()) {
410 case MCSymbolRefExpr::VK_GOTTPOFF:
411 case MCSymbolRefExpr::VK_INDNTPOFF:
412 case MCSymbolRefExpr::VK_NTPOFF:
413 case MCSymbolRefExpr::VK_GOTNTPOFF:
414 case MCSymbolRefExpr::VK_TLSGD:
415 case MCSymbolRefExpr::VK_TLSLD:
416 case MCSymbolRefExpr::VK_TLSLDM:
417 case MCSymbolRefExpr::VK_TPOFF:
418 case MCSymbolRefExpr::VK_DTPOFF:
419 case MCSymbolRefExpr::VK_Mips_TLSGD:
420 case MCSymbolRefExpr::VK_Mips_GOTTPREL:
421 case MCSymbolRefExpr::VK_Mips_TPREL_HI:
422 case MCSymbolRefExpr::VK_Mips_TPREL_LO:
423 case MCSymbolRefExpr::VK_PPC_DTPMOD:
424 case MCSymbolRefExpr::VK_PPC_TPREL:
425 case MCSymbolRefExpr::VK_PPC_TPREL_LO:
426 case MCSymbolRefExpr::VK_PPC_TPREL_HI:
427 case MCSymbolRefExpr::VK_PPC_TPREL_HA:
428 case MCSymbolRefExpr::VK_PPC_TPREL_HIGHER:
429 case MCSymbolRefExpr::VK_PPC_TPREL_HIGHERA:
430 case MCSymbolRefExpr::VK_PPC_TPREL_HIGHEST:
431 case MCSymbolRefExpr::VK_PPC_TPREL_HIGHESTA:
432 case MCSymbolRefExpr::VK_PPC_DTPREL:
433 case MCSymbolRefExpr::VK_PPC_DTPREL_LO:
434 case MCSymbolRefExpr::VK_PPC_DTPREL_HI:
435 case MCSymbolRefExpr::VK_PPC_DTPREL_HA:
436 case MCSymbolRefExpr::VK_PPC_DTPREL_HIGHER:
437 case MCSymbolRefExpr::VK_PPC_DTPREL_HIGHERA:
438 case MCSymbolRefExpr::VK_PPC_DTPREL_HIGHEST:
439 case MCSymbolRefExpr::VK_PPC_DTPREL_HIGHESTA:
440 case MCSymbolRefExpr::VK_PPC_GOT_TPREL:
441 case MCSymbolRefExpr::VK_PPC_GOT_TPREL_LO:
442 case MCSymbolRefExpr::VK_PPC_GOT_TPREL_HI:
443 case MCSymbolRefExpr::VK_PPC_GOT_TPREL_HA:
444 case MCSymbolRefExpr::VK_PPC_GOT_DTPREL:
445 case MCSymbolRefExpr::VK_PPC_GOT_DTPREL_LO:
446 case MCSymbolRefExpr::VK_PPC_GOT_DTPREL_HI:
447 case MCSymbolRefExpr::VK_PPC_GOT_DTPREL_HA:
448 case MCSymbolRefExpr::VK_PPC_TLS:
449 case MCSymbolRefExpr::VK_PPC_GOT_TLSGD:
450 case MCSymbolRefExpr::VK_PPC_GOT_TLSGD_LO:
451 case MCSymbolRefExpr::VK_PPC_GOT_TLSGD_HI:
452 case MCSymbolRefExpr::VK_PPC_GOT_TLSGD_HA:
453 case MCSymbolRefExpr::VK_PPC_TLSGD:
454 case MCSymbolRefExpr::VK_PPC_GOT_TLSLD:
455 case MCSymbolRefExpr::VK_PPC_GOT_TLSLD_LO:
456 case MCSymbolRefExpr::VK_PPC_GOT_TLSLD_HI:
457 case MCSymbolRefExpr::VK_PPC_GOT_TLSLD_HA:
458 case MCSymbolRefExpr::VK_PPC_TLSLD:
461 MCSymbolData &SD = getAssembler().getOrCreateSymbolData(symRef.getSymbol());
462 MCELF::SetType(SD, ELF::STT_TLS);
467 fixSymbolsInTLSFixups(cast<MCUnaryExpr>(expr)->getSubExpr());
472 void MCELFStreamer::EmitInstToFragment(const MCInst &Inst,
473 const MCSubtargetInfo &STI) {
474 this->MCObjectStreamer::EmitInstToFragment(Inst, STI);
475 MCRelaxableFragment &F = *cast<MCRelaxableFragment>(getCurrentFragment());
477 for (unsigned i = 0, e = F.getFixups().size(); i != e; ++i)
478 fixSymbolsInTLSFixups(F.getFixups()[i].getValue());
481 void MCELFStreamer::EmitInstToData(const MCInst &Inst,
482 const MCSubtargetInfo &STI) {
483 MCAssembler &Assembler = getAssembler();
484 SmallVector<MCFixup, 4> Fixups;
485 SmallString<256> Code;
486 raw_svector_ostream VecOS(Code);
487 Assembler.getEmitter().encodeInstruction(Inst, VecOS, Fixups, STI);
490 for (unsigned i = 0, e = Fixups.size(); i != e; ++i)
491 fixSymbolsInTLSFixups(Fixups[i].getValue());
493 // There are several possibilities here:
495 // If bundling is disabled, append the encoded instruction to the current data
496 // fragment (or create a new such fragment if the current fragment is not a
499 // If bundling is enabled:
500 // - If we're not in a bundle-locked group, emit the instruction into a
501 // fragment of its own. If there are no fixups registered for the
502 // instruction, emit a MCCompactEncodedInstFragment. Otherwise, emit a
504 // - If we're in a bundle-locked group, append the instruction to the current
505 // data fragment because we want all the instructions in a group to get into
506 // the same fragment. Be careful not to do that for the first instruction in
507 // the group, though.
510 if (Assembler.isBundlingEnabled()) {
511 MCSection &Sec = *getCurrentSectionOnly();
512 if (Assembler.getRelaxAll() && isBundleLocked())
513 // If the -mc-relax-all flag is used and we are bundle-locked, we re-use
514 // the current bundle group.
515 DF = BundleGroups.back();
516 else if (Assembler.getRelaxAll() && !isBundleLocked())
517 // When not in a bundle-locked group and the -mc-relax-all flag is used,
518 // we create a new temporary fragment which will be later merged into
519 // the current fragment.
520 DF = new MCDataFragment();
521 else if (isBundleLocked() && !Sec.isBundleGroupBeforeFirstInst())
522 // If we are bundle-locked, we re-use the current fragment.
523 // The bundle-locking directive ensures this is a new data fragment.
524 DF = cast<MCDataFragment>(getCurrentFragment());
525 else if (!isBundleLocked() && Fixups.size() == 0) {
526 // Optimize memory usage by emitting the instruction to a
527 // MCCompactEncodedInstFragment when not in a bundle-locked group and
528 // there are no fixups registered.
529 MCCompactEncodedInstFragment *CEIF = new MCCompactEncodedInstFragment();
531 CEIF->getContents().append(Code.begin(), Code.end());
534 DF = new MCDataFragment();
537 if (Sec.getBundleLockState() == MCSection::BundleLockedAlignToEnd) {
538 // If this fragment is for a group marked "align_to_end", set a flag
539 // in the fragment. This can happen after the fragment has already been
540 // created if there are nested bundle_align groups and an inner one
541 // is the one marked align_to_end.
542 DF->setAlignToBundleEnd(true);
545 // We're now emitting an instruction in a bundle group, so this flag has
547 Sec.setBundleGroupBeforeFirstInst(false);
549 DF = getOrCreateDataFragment();
552 // Add the fixups and data.
553 for (unsigned i = 0, e = Fixups.size(); i != e; ++i) {
554 Fixups[i].setOffset(Fixups[i].getOffset() + DF->getContents().size());
555 DF->getFixups().push_back(Fixups[i]);
557 DF->setHasInstructions(true);
558 DF->getContents().append(Code.begin(), Code.end());
560 if (Assembler.isBundlingEnabled() && Assembler.getRelaxAll()) {
561 if (!isBundleLocked()) {
562 mergeFragment(getOrCreateDataFragment(), DF);
568 void MCELFStreamer::EmitBundleAlignMode(unsigned AlignPow2) {
569 assert(AlignPow2 <= 30 && "Invalid bundle alignment");
570 MCAssembler &Assembler = getAssembler();
571 if (AlignPow2 > 0 && (Assembler.getBundleAlignSize() == 0 ||
572 Assembler.getBundleAlignSize() == 1U << AlignPow2))
573 Assembler.setBundleAlignSize(1U << AlignPow2);
575 report_fatal_error(".bundle_align_mode cannot be changed once set");
578 void MCELFStreamer::EmitBundleLock(bool AlignToEnd) {
579 MCSection &Sec = *getCurrentSectionOnly();
583 if (!getAssembler().isBundlingEnabled())
584 report_fatal_error(".bundle_lock forbidden when bundling is disabled");
586 if (!isBundleLocked())
587 Sec.setBundleGroupBeforeFirstInst(true);
589 if (getAssembler().getRelaxAll() && !isBundleLocked()) {
590 // TODO: drop the lock state and set directly in the fragment
591 MCDataFragment *DF = new MCDataFragment();
592 BundleGroups.push_back(DF);
595 Sec.setBundleLockState(AlignToEnd ? MCSection::BundleLockedAlignToEnd
596 : MCSection::BundleLocked);
599 void MCELFStreamer::EmitBundleUnlock() {
600 MCSection &Sec = *getCurrentSectionOnly();
603 if (!getAssembler().isBundlingEnabled())
604 report_fatal_error(".bundle_unlock forbidden when bundling is disabled");
605 else if (!isBundleLocked())
606 report_fatal_error(".bundle_unlock without matching lock");
607 else if (Sec.isBundleGroupBeforeFirstInst())
608 report_fatal_error("Empty bundle-locked group is forbidden");
610 // When the -mc-relax-all flag is used, we emit instructions to fragments
611 // stored on a stack. When the bundle unlock is emited, we pop a fragment
612 // from the stack a merge it to the one below.
613 if (getAssembler().getRelaxAll()) {
614 assert(!BundleGroups.empty() && "There are no bundle groups");
615 MCDataFragment *DF = BundleGroups.back();
617 // FIXME: Use BundleGroups to track the lock state instead.
618 Sec.setBundleLockState(MCSection::NotBundleLocked);
620 // FIXME: Use more separate fragments for nested groups.
621 if (!isBundleLocked()) {
622 mergeFragment(getOrCreateDataFragment(), DF);
623 BundleGroups.pop_back();
627 if (Sec.getBundleLockState() != MCSection::BundleLockedAlignToEnd)
628 getOrCreateDataFragment()->setAlignToBundleEnd(false);
630 Sec.setBundleLockState(MCSection::NotBundleLocked);
633 void MCELFStreamer::Flush() {
634 for (std::vector<LocalCommon>::const_iterator i = LocalCommons.begin(),
635 e = LocalCommons.end();
637 const MCSymbol &Symbol = *i->Symbol;
638 uint64_t Size = i->Size;
639 unsigned ByteAlignment = i->ByteAlignment;
640 MCSection &Section = Symbol.getSection();
642 getAssembler().registerSection(Section);
643 new MCAlignFragment(ByteAlignment, 0, 1, ByteAlignment, &Section);
645 MCFragment *F = new MCFillFragment(0, 0, Size, &Section);
646 Symbol.getData().setFragment(F);
648 // Update the maximum alignment of the section if necessary.
649 if (ByteAlignment > Section.getAlignment())
650 Section.setAlignment(ByteAlignment);
653 LocalCommons.clear();
656 void MCELFStreamer::FinishImpl() {
657 // Ensure the last section gets aligned if necessary.
658 MCSection *CurSection = getCurrentSectionOnly();
659 setSectionAlignmentForBundling(getAssembler(), CurSection);
665 this->MCObjectStreamer::FinishImpl();
668 MCStreamer *llvm::createELFStreamer(MCContext &Context, MCAsmBackend &MAB,
669 raw_pwrite_stream &OS, MCCodeEmitter *CE,
671 MCELFStreamer *S = new MCELFStreamer(Context, MAB, OS, CE);
673 S->getAssembler().setRelaxAll(true);
677 void MCELFStreamer::EmitThumbFunc(MCSymbol *Func) {
678 llvm_unreachable("Generic ELF doesn't support this directive");
681 void MCELFStreamer::EmitSymbolDesc(MCSymbol *Symbol, unsigned DescValue) {
682 llvm_unreachable("ELF doesn't support this directive");
685 void MCELFStreamer::BeginCOFFSymbolDef(const MCSymbol *Symbol) {
686 llvm_unreachable("ELF doesn't support this directive");
689 void MCELFStreamer::EmitCOFFSymbolStorageClass(int StorageClass) {
690 llvm_unreachable("ELF doesn't support this directive");
693 void MCELFStreamer::EmitCOFFSymbolType(int Type) {
694 llvm_unreachable("ELF doesn't support this directive");
697 void MCELFStreamer::EndCOFFSymbolDef() {
698 llvm_unreachable("ELF doesn't support this directive");
701 void MCELFStreamer::EmitZerofill(MCSection *Section, MCSymbol *Symbol,
702 uint64_t Size, unsigned ByteAlignment) {
703 llvm_unreachable("ELF doesn't support this directive");
706 void MCELFStreamer::EmitTBSSSymbol(MCSection *Section, MCSymbol *Symbol,
707 uint64_t Size, unsigned ByteAlignment) {
708 llvm_unreachable("ELF doesn't support this directive");