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/SmallString.h"
16 #include "llvm/ADT/SmallVector.h"
17 #include "llvm/BinaryFormat/ELF.h"
18 #include "llvm/MC/MCAsmBackend.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/MCExpr.h"
24 #include "llvm/MC/MCFixup.h"
25 #include "llvm/MC/MCFragment.h"
26 #include "llvm/MC/MCObjectFileInfo.h"
27 #include "llvm/MC/MCObjectWriter.h"
28 #include "llvm/MC/MCSection.h"
29 #include "llvm/MC/MCSectionELF.h"
30 #include "llvm/MC/MCStreamer.h"
31 #include "llvm/MC/MCSymbol.h"
32 #include "llvm/MC/MCSymbolELF.h"
33 #include "llvm/Support/Casting.h"
34 #include "llvm/Support/ErrorHandling.h"
35 #include "llvm/Support/TargetRegistry.h"
36 #include "llvm/Support/raw_ostream.h"
42 MCELFStreamer::MCELFStreamer(MCContext &Context,
43 std::unique_ptr<MCAsmBackend> TAB,
44 std::unique_ptr<MCObjectWriter> OW,
45 std::unique_ptr<MCCodeEmitter> Emitter)
46 : MCObjectStreamer(Context, std::move(TAB), std::move(OW),
47 std::move(Emitter)) {}
49 bool MCELFStreamer::isBundleLocked() const {
50 return getCurrentSectionOnly()->isBundleLocked();
53 void MCELFStreamer::mergeFragment(MCDataFragment *DF,
55 MCAssembler &Assembler = getAssembler();
57 if (Assembler.isBundlingEnabled() && Assembler.getRelaxAll()) {
58 uint64_t FSize = EF->getContents().size();
60 if (FSize > Assembler.getBundleAlignSize())
61 report_fatal_error("Fragment can't be larger than a bundle size");
63 uint64_t RequiredBundlePadding = computeBundlePadding(
64 Assembler, EF, DF->getContents().size(), FSize);
66 if (RequiredBundlePadding > UINT8_MAX)
67 report_fatal_error("Padding cannot exceed 255 bytes");
69 if (RequiredBundlePadding > 0) {
70 SmallString<256> Code;
71 raw_svector_ostream VecOS(Code);
72 EF->setBundlePadding(static_cast<uint8_t>(RequiredBundlePadding));
73 Assembler.writeFragmentPadding(VecOS, *EF, FSize);
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 if (DF->getSubtargetInfo() == nullptr && EF->getSubtargetInfo())
87 DF->setHasInstructions(*EF->getSubtargetInfo());
88 DF->getContents().append(EF->getContents().begin(), EF->getContents().end());
91 void MCELFStreamer::InitSections(bool NoExecStack) {
92 MCContext &Ctx = getContext();
93 SwitchSection(Ctx.getObjectFileInfo()->getTextSection());
97 SwitchSection(Ctx.getAsmInfo()->getNonexecutableStackSection(Ctx));
100 void MCELFStreamer::EmitLabel(MCSymbol *S, SMLoc Loc) {
101 auto *Symbol = cast<MCSymbolELF>(S);
102 MCObjectStreamer::EmitLabel(Symbol, Loc);
104 const MCSectionELF &Section =
105 static_cast<const MCSectionELF &>(*getCurrentSectionOnly());
106 if (Section.getFlags() & ELF::SHF_TLS)
107 Symbol->setType(ELF::STT_TLS);
110 void MCELFStreamer::EmitLabel(MCSymbol *S, SMLoc Loc, MCFragment *F) {
111 auto *Symbol = cast<MCSymbolELF>(S);
112 MCObjectStreamer::EmitLabel(Symbol, Loc, F);
114 const MCSectionELF &Section =
115 static_cast<const MCSectionELF &>(*getCurrentSectionOnly());
116 if (Section.getFlags() & ELF::SHF_TLS)
117 Symbol->setType(ELF::STT_TLS);
120 void MCELFStreamer::EmitAssemblerFlag(MCAssemblerFlag Flag) {
121 // Let the target do whatever target specific stuff it needs to do.
122 getAssembler().getBackend().handleAssemblerFlag(Flag);
123 // Do any generic stuff we need to do.
125 case MCAF_SyntaxUnified: return; // no-op here.
126 case MCAF_Code16: return; // Change parsing mode; no-op here.
127 case MCAF_Code32: return; // Change parsing mode; no-op here.
128 case MCAF_Code64: return; // Change parsing mode; no-op here.
129 case MCAF_SubsectionsViaSymbols:
130 getAssembler().setSubsectionsViaSymbols(true);
134 llvm_unreachable("invalid assembler flag!");
137 // If bundle alignment is used and there are any instructions in the section, it
138 // needs to be aligned to at least the bundle size.
139 static void setSectionAlignmentForBundling(const MCAssembler &Assembler,
140 MCSection *Section) {
141 if (Section && Assembler.isBundlingEnabled() && Section->hasInstructions() &&
142 Section->getAlignment() < Assembler.getBundleAlignSize())
143 Section->setAlignment(Assembler.getBundleAlignSize());
146 void MCELFStreamer::ChangeSection(MCSection *Section,
147 const MCExpr *Subsection) {
148 MCSection *CurSection = getCurrentSectionOnly();
149 if (CurSection && isBundleLocked())
150 report_fatal_error("Unterminated .bundle_lock when changing a section");
152 MCAssembler &Asm = getAssembler();
153 // Ensure the previous section gets aligned if necessary.
154 setSectionAlignmentForBundling(Asm, CurSection);
155 auto *SectionELF = static_cast<const MCSectionELF *>(Section);
156 const MCSymbol *Grp = SectionELF->getGroup();
158 Asm.registerSymbol(*Grp);
160 changeSectionImpl(Section, Subsection);
161 Asm.registerSymbol(*Section->getBeginSymbol());
164 void MCELFStreamer::EmitWeakReference(MCSymbol *Alias, const MCSymbol *Symbol) {
165 getAssembler().registerSymbol(*Symbol);
166 const MCExpr *Value = MCSymbolRefExpr::create(
167 Symbol, MCSymbolRefExpr::VK_WEAKREF, getContext());
168 Alias->setVariableValue(Value);
171 // When GNU as encounters more than one .type declaration for an object it seems
172 // to use a mechanism similar to the one below to decide which type is actually
173 // used in the object file. The greater of T1 and T2 is selected based on the
174 // following ordering:
175 // STT_NOTYPE < STT_OBJECT < STT_FUNC < STT_GNU_IFUNC < STT_TLS < anything else
176 // If neither T1 < T2 nor T2 < T1 according to this ordering, use T2 (the user
178 static unsigned CombineSymbolTypes(unsigned T1, unsigned T2) {
179 for (unsigned Type : {ELF::STT_NOTYPE, ELF::STT_OBJECT, ELF::STT_FUNC,
180 ELF::STT_GNU_IFUNC, ELF::STT_TLS}) {
190 bool MCELFStreamer::EmitSymbolAttribute(MCSymbol *S, MCSymbolAttr Attribute) {
191 auto *Symbol = cast<MCSymbolELF>(S);
193 // Adding a symbol attribute always introduces the symbol, note that an
194 // important side effect of calling registerSymbol here is to register
195 // the symbol with the assembler.
196 getAssembler().registerSymbol(*Symbol);
198 // The implementation of symbol attributes is designed to match 'as', but it
199 // leaves much to desired. It doesn't really make sense to arbitrarily add and
200 // remove flags, but 'as' allows this (in particular, see .desc).
202 // In the future it might be worth trying to make these operations more well
205 case MCSA_LazyReference:
207 case MCSA_SymbolResolver:
208 case MCSA_PrivateExtern:
209 case MCSA_WeakDefinition:
210 case MCSA_WeakDefAutoPrivate:
212 case MCSA_IndirectSymbol:
215 case MCSA_NoDeadStrip:
219 case MCSA_ELF_TypeGnuUniqueObject:
220 Symbol->setType(CombineSymbolTypes(Symbol->getType(), ELF::STT_OBJECT));
221 Symbol->setBinding(ELF::STB_GNU_UNIQUE);
222 Symbol->setExternal(true);
226 Symbol->setBinding(ELF::STB_GLOBAL);
227 Symbol->setExternal(true);
230 case MCSA_WeakReference:
232 Symbol->setBinding(ELF::STB_WEAK);
233 Symbol->setExternal(true);
237 Symbol->setBinding(ELF::STB_LOCAL);
238 Symbol->setExternal(false);
241 case MCSA_ELF_TypeFunction:
242 Symbol->setType(CombineSymbolTypes(Symbol->getType(), ELF::STT_FUNC));
245 case MCSA_ELF_TypeIndFunction:
246 Symbol->setType(CombineSymbolTypes(Symbol->getType(), ELF::STT_GNU_IFUNC));
249 case MCSA_ELF_TypeObject:
250 Symbol->setType(CombineSymbolTypes(Symbol->getType(), ELF::STT_OBJECT));
253 case MCSA_ELF_TypeTLS:
254 Symbol->setType(CombineSymbolTypes(Symbol->getType(), ELF::STT_TLS));
257 case MCSA_ELF_TypeCommon:
258 // TODO: Emit these as a common symbol.
259 Symbol->setType(CombineSymbolTypes(Symbol->getType(), ELF::STT_OBJECT));
262 case MCSA_ELF_TypeNoType:
263 Symbol->setType(CombineSymbolTypes(Symbol->getType(), ELF::STT_NOTYPE));
267 Symbol->setVisibility(ELF::STV_PROTECTED);
271 Symbol->setVisibility(ELF::STV_HIDDEN);
275 Symbol->setVisibility(ELF::STV_INTERNAL);
279 llvm_unreachable("ELF doesn't support the .alt_entry attribute");
285 void MCELFStreamer::EmitCommonSymbol(MCSymbol *S, uint64_t Size,
286 unsigned ByteAlignment) {
287 auto *Symbol = cast<MCSymbolELF>(S);
288 getAssembler().registerSymbol(*Symbol);
290 if (!Symbol->isBindingSet()) {
291 Symbol->setBinding(ELF::STB_GLOBAL);
292 Symbol->setExternal(true);
295 Symbol->setType(ELF::STT_OBJECT);
297 if (Symbol->getBinding() == ELF::STB_LOCAL) {
298 MCSection &Section = *getAssembler().getContext().getELFSection(
299 ".bss", ELF::SHT_NOBITS, ELF::SHF_WRITE | ELF::SHF_ALLOC);
300 MCSectionSubPair P = getCurrentSection();
301 SwitchSection(&Section);
303 EmitValueToAlignment(ByteAlignment, 0, 1, 0);
307 // Update the maximum alignment of the section if necessary.
308 if (ByteAlignment > Section.getAlignment())
309 Section.setAlignment(ByteAlignment);
311 SwitchSection(P.first, P.second);
313 if(Symbol->declareCommon(Size, ByteAlignment))
314 report_fatal_error("Symbol: " + Symbol->getName() +
315 " redeclared as different type");
318 cast<MCSymbolELF>(Symbol)
319 ->setSize(MCConstantExpr::create(Size, getContext()));
322 void MCELFStreamer::emitELFSize(MCSymbol *Symbol, const MCExpr *Value) {
323 cast<MCSymbolELF>(Symbol)->setSize(Value);
326 void MCELFStreamer::emitELFSymverDirective(StringRef AliasName,
327 const MCSymbol *Aliasee) {
328 getAssembler().Symvers.push_back({AliasName, Aliasee});
331 void MCELFStreamer::EmitLocalCommonSymbol(MCSymbol *S, uint64_t Size,
332 unsigned ByteAlignment) {
333 auto *Symbol = cast<MCSymbolELF>(S);
334 // FIXME: Should this be caught and done earlier?
335 getAssembler().registerSymbol(*Symbol);
336 Symbol->setBinding(ELF::STB_LOCAL);
337 Symbol->setExternal(false);
338 EmitCommonSymbol(Symbol, Size, ByteAlignment);
341 void MCELFStreamer::EmitValueImpl(const MCExpr *Value, unsigned Size,
343 if (isBundleLocked())
344 report_fatal_error("Emitting values inside a locked bundle is forbidden");
345 fixSymbolsInTLSFixups(Value);
346 MCObjectStreamer::EmitValueImpl(Value, Size, Loc);
349 void MCELFStreamer::EmitValueToAlignment(unsigned ByteAlignment,
352 unsigned MaxBytesToEmit) {
353 if (isBundleLocked())
354 report_fatal_error("Emitting values inside a locked bundle is forbidden");
355 MCObjectStreamer::EmitValueToAlignment(ByteAlignment, Value,
356 ValueSize, MaxBytesToEmit);
359 void MCELFStreamer::emitCGProfileEntry(const MCSymbolRefExpr *From,
360 const MCSymbolRefExpr *To,
362 getAssembler().CGProfile.push_back({From, To, Count});
365 void MCELFStreamer::EmitIdent(StringRef IdentString) {
366 MCSection *Comment = getAssembler().getContext().getELFSection(
367 ".comment", ELF::SHT_PROGBITS, ELF::SHF_MERGE | ELF::SHF_STRINGS, 1, "");
369 SwitchSection(Comment);
374 EmitBytes(IdentString);
379 void MCELFStreamer::fixSymbolsInTLSFixups(const MCExpr *expr) {
380 switch (expr->getKind()) {
382 cast<MCTargetExpr>(expr)->fixELFSymbolsInTLSFixups(getAssembler());
384 case MCExpr::Constant:
387 case MCExpr::Binary: {
388 const MCBinaryExpr *be = cast<MCBinaryExpr>(expr);
389 fixSymbolsInTLSFixups(be->getLHS());
390 fixSymbolsInTLSFixups(be->getRHS());
394 case MCExpr::SymbolRef: {
395 const MCSymbolRefExpr &symRef = *cast<MCSymbolRefExpr>(expr);
396 switch (symRef.getKind()) {
399 case MCSymbolRefExpr::VK_GOTTPOFF:
400 case MCSymbolRefExpr::VK_INDNTPOFF:
401 case MCSymbolRefExpr::VK_NTPOFF:
402 case MCSymbolRefExpr::VK_GOTNTPOFF:
403 case MCSymbolRefExpr::VK_TLSGD:
404 case MCSymbolRefExpr::VK_TLSLD:
405 case MCSymbolRefExpr::VK_TLSLDM:
406 case MCSymbolRefExpr::VK_TPOFF:
407 case MCSymbolRefExpr::VK_TPREL:
408 case MCSymbolRefExpr::VK_DTPOFF:
409 case MCSymbolRefExpr::VK_DTPREL:
410 case MCSymbolRefExpr::VK_PPC_DTPMOD:
411 case MCSymbolRefExpr::VK_PPC_TPREL_LO:
412 case MCSymbolRefExpr::VK_PPC_TPREL_HI:
413 case MCSymbolRefExpr::VK_PPC_TPREL_HA:
414 case MCSymbolRefExpr::VK_PPC_TPREL_HIGH:
415 case MCSymbolRefExpr::VK_PPC_TPREL_HIGHA:
416 case MCSymbolRefExpr::VK_PPC_TPREL_HIGHER:
417 case MCSymbolRefExpr::VK_PPC_TPREL_HIGHERA:
418 case MCSymbolRefExpr::VK_PPC_TPREL_HIGHEST:
419 case MCSymbolRefExpr::VK_PPC_TPREL_HIGHESTA:
420 case MCSymbolRefExpr::VK_PPC_DTPREL_LO:
421 case MCSymbolRefExpr::VK_PPC_DTPREL_HI:
422 case MCSymbolRefExpr::VK_PPC_DTPREL_HA:
423 case MCSymbolRefExpr::VK_PPC_DTPREL_HIGH:
424 case MCSymbolRefExpr::VK_PPC_DTPREL_HIGHA:
425 case MCSymbolRefExpr::VK_PPC_DTPREL_HIGHER:
426 case MCSymbolRefExpr::VK_PPC_DTPREL_HIGHERA:
427 case MCSymbolRefExpr::VK_PPC_DTPREL_HIGHEST:
428 case MCSymbolRefExpr::VK_PPC_DTPREL_HIGHESTA:
429 case MCSymbolRefExpr::VK_PPC_GOT_TPREL:
430 case MCSymbolRefExpr::VK_PPC_GOT_TPREL_LO:
431 case MCSymbolRefExpr::VK_PPC_GOT_TPREL_HI:
432 case MCSymbolRefExpr::VK_PPC_GOT_TPREL_HA:
433 case MCSymbolRefExpr::VK_PPC_GOT_DTPREL:
434 case MCSymbolRefExpr::VK_PPC_GOT_DTPREL_LO:
435 case MCSymbolRefExpr::VK_PPC_GOT_DTPREL_HI:
436 case MCSymbolRefExpr::VK_PPC_GOT_DTPREL_HA:
437 case MCSymbolRefExpr::VK_PPC_TLS:
438 case MCSymbolRefExpr::VK_PPC_GOT_TLSGD:
439 case MCSymbolRefExpr::VK_PPC_GOT_TLSGD_LO:
440 case MCSymbolRefExpr::VK_PPC_GOT_TLSGD_HI:
441 case MCSymbolRefExpr::VK_PPC_GOT_TLSGD_HA:
442 case MCSymbolRefExpr::VK_PPC_TLSGD:
443 case MCSymbolRefExpr::VK_PPC_GOT_TLSLD:
444 case MCSymbolRefExpr::VK_PPC_GOT_TLSLD_LO:
445 case MCSymbolRefExpr::VK_PPC_GOT_TLSLD_HI:
446 case MCSymbolRefExpr::VK_PPC_GOT_TLSLD_HA:
447 case MCSymbolRefExpr::VK_PPC_TLSLD:
450 getAssembler().registerSymbol(symRef.getSymbol());
451 cast<MCSymbolELF>(symRef.getSymbol()).setType(ELF::STT_TLS);
456 fixSymbolsInTLSFixups(cast<MCUnaryExpr>(expr)->getSubExpr());
461 void MCELFStreamer::finalizeCGProfileEntry(const MCSymbolRefExpr *&SRE) {
462 const MCSymbol *S = &SRE->getSymbol();
463 if (S->isTemporary()) {
464 if (!S->isInSection()) {
465 getContext().reportError(
466 SRE->getLoc(), Twine("Reference to undefined temporary symbol ") +
467 "`" + S->getName() + "`");
470 S = S->getSection().getBeginSymbol();
473 MCSymbolRefExpr::create(S, SRE->getKind(), getContext(), SRE->getLoc());
476 // Not a temporary, referece it as a weak undefined.
478 getAssembler().registerSymbol(*S, &Created);
480 cast<MCSymbolELF>(S)->setBinding(ELF::STB_WEAK);
481 cast<MCSymbolELF>(S)->setExternal(true);
485 void MCELFStreamer::finalizeCGProfile() {
486 for (MCAssembler::CGProfileEntry &E : getAssembler().CGProfile) {
487 finalizeCGProfileEntry(E.From);
488 finalizeCGProfileEntry(E.To);
492 void MCELFStreamer::EmitInstToFragment(const MCInst &Inst,
493 const MCSubtargetInfo &STI) {
494 this->MCObjectStreamer::EmitInstToFragment(Inst, STI);
495 MCRelaxableFragment &F = *cast<MCRelaxableFragment>(getCurrentFragment());
497 for (unsigned i = 0, e = F.getFixups().size(); i != e; ++i)
498 fixSymbolsInTLSFixups(F.getFixups()[i].getValue());
501 // A fragment can only have one Subtarget, and when bundling is enabled we
502 // sometimes need to use the same fragment. We give an error if there
503 // are conflicting Subtargets.
504 static void CheckBundleSubtargets(const MCSubtargetInfo *OldSTI,
505 const MCSubtargetInfo *NewSTI) {
506 if (OldSTI && NewSTI && OldSTI != NewSTI)
507 report_fatal_error("A Bundle can only have one Subtarget.");
510 void MCELFStreamer::EmitInstToData(const MCInst &Inst,
511 const MCSubtargetInfo &STI) {
512 MCAssembler &Assembler = getAssembler();
513 SmallVector<MCFixup, 4> Fixups;
514 SmallString<256> Code;
515 raw_svector_ostream VecOS(Code);
516 Assembler.getEmitter().encodeInstruction(Inst, VecOS, Fixups, STI);
518 for (unsigned i = 0, e = Fixups.size(); i != e; ++i)
519 fixSymbolsInTLSFixups(Fixups[i].getValue());
521 // There are several possibilities here:
523 // If bundling is disabled, append the encoded instruction to the current data
524 // fragment (or create a new such fragment if the current fragment is not a
525 // data fragment, or the Subtarget has changed).
527 // If bundling is enabled:
528 // - If we're not in a bundle-locked group, emit the instruction into a
529 // fragment of its own. If there are no fixups registered for the
530 // instruction, emit a MCCompactEncodedInstFragment. Otherwise, emit a
532 // - If we're in a bundle-locked group, append the instruction to the current
533 // data fragment because we want all the instructions in a group to get into
534 // the same fragment. Be careful not to do that for the first instruction in
535 // the group, though.
538 if (Assembler.isBundlingEnabled()) {
539 MCSection &Sec = *getCurrentSectionOnly();
540 if (Assembler.getRelaxAll() && isBundleLocked()) {
541 // If the -mc-relax-all flag is used and we are bundle-locked, we re-use
542 // the current bundle group.
543 DF = BundleGroups.back();
544 CheckBundleSubtargets(DF->getSubtargetInfo(), &STI);
546 else if (Assembler.getRelaxAll() && !isBundleLocked())
547 // When not in a bundle-locked group and the -mc-relax-all flag is used,
548 // we create a new temporary fragment which will be later merged into
549 // the current fragment.
550 DF = new MCDataFragment();
551 else if (isBundleLocked() && !Sec.isBundleGroupBeforeFirstInst()) {
552 // If we are bundle-locked, we re-use the current fragment.
553 // The bundle-locking directive ensures this is a new data fragment.
554 DF = cast<MCDataFragment>(getCurrentFragment());
555 CheckBundleSubtargets(DF->getSubtargetInfo(), &STI);
557 else if (!isBundleLocked() && Fixups.size() == 0) {
558 // Optimize memory usage by emitting the instruction to a
559 // MCCompactEncodedInstFragment when not in a bundle-locked group and
560 // there are no fixups registered.
561 MCCompactEncodedInstFragment *CEIF = new MCCompactEncodedInstFragment();
563 CEIF->getContents().append(Code.begin(), Code.end());
564 CEIF->setHasInstructions(STI);
567 DF = new MCDataFragment();
570 if (Sec.getBundleLockState() == MCSection::BundleLockedAlignToEnd) {
571 // If this fragment is for a group marked "align_to_end", set a flag
572 // in the fragment. This can happen after the fragment has already been
573 // created if there are nested bundle_align groups and an inner one
574 // is the one marked align_to_end.
575 DF->setAlignToBundleEnd(true);
578 // We're now emitting an instruction in a bundle group, so this flag has
580 Sec.setBundleGroupBeforeFirstInst(false);
582 DF = getOrCreateDataFragment(&STI);
585 // Add the fixups and data.
586 for (unsigned i = 0, e = Fixups.size(); i != e; ++i) {
587 Fixups[i].setOffset(Fixups[i].getOffset() + DF->getContents().size());
588 DF->getFixups().push_back(Fixups[i]);
590 DF->setHasInstructions(STI);
591 DF->getContents().append(Code.begin(), Code.end());
593 if (Assembler.isBundlingEnabled() && Assembler.getRelaxAll()) {
594 if (!isBundleLocked()) {
595 mergeFragment(getOrCreateDataFragment(&STI), DF);
601 void MCELFStreamer::EmitBundleAlignMode(unsigned AlignPow2) {
602 assert(AlignPow2 <= 30 && "Invalid bundle alignment");
603 MCAssembler &Assembler = getAssembler();
604 if (AlignPow2 > 0 && (Assembler.getBundleAlignSize() == 0 ||
605 Assembler.getBundleAlignSize() == 1U << AlignPow2))
606 Assembler.setBundleAlignSize(1U << AlignPow2);
608 report_fatal_error(".bundle_align_mode cannot be changed once set");
611 void MCELFStreamer::EmitBundleLock(bool AlignToEnd) {
612 MCSection &Sec = *getCurrentSectionOnly();
616 if (!getAssembler().isBundlingEnabled())
617 report_fatal_error(".bundle_lock forbidden when bundling is disabled");
619 if (!isBundleLocked())
620 Sec.setBundleGroupBeforeFirstInst(true);
622 if (getAssembler().getRelaxAll() && !isBundleLocked()) {
623 // TODO: drop the lock state and set directly in the fragment
624 MCDataFragment *DF = new MCDataFragment();
625 BundleGroups.push_back(DF);
628 Sec.setBundleLockState(AlignToEnd ? MCSection::BundleLockedAlignToEnd
629 : MCSection::BundleLocked);
632 void MCELFStreamer::EmitBundleUnlock() {
633 MCSection &Sec = *getCurrentSectionOnly();
636 if (!getAssembler().isBundlingEnabled())
637 report_fatal_error(".bundle_unlock forbidden when bundling is disabled");
638 else if (!isBundleLocked())
639 report_fatal_error(".bundle_unlock without matching lock");
640 else if (Sec.isBundleGroupBeforeFirstInst())
641 report_fatal_error("Empty bundle-locked group is forbidden");
643 // When the -mc-relax-all flag is used, we emit instructions to fragments
644 // stored on a stack. When the bundle unlock is emitted, we pop a fragment
645 // from the stack a merge it to the one below.
646 if (getAssembler().getRelaxAll()) {
647 assert(!BundleGroups.empty() && "There are no bundle groups");
648 MCDataFragment *DF = BundleGroups.back();
650 // FIXME: Use BundleGroups to track the lock state instead.
651 Sec.setBundleLockState(MCSection::NotBundleLocked);
653 // FIXME: Use more separate fragments for nested groups.
654 if (!isBundleLocked()) {
655 mergeFragment(getOrCreateDataFragment(DF->getSubtargetInfo()), DF);
656 BundleGroups.pop_back();
660 if (Sec.getBundleLockState() != MCSection::BundleLockedAlignToEnd)
661 getOrCreateDataFragment()->setAlignToBundleEnd(false);
663 Sec.setBundleLockState(MCSection::NotBundleLocked);
666 void MCELFStreamer::FinishImpl() {
667 // Ensure the last section gets aligned if necessary.
668 MCSection *CurSection = getCurrentSectionOnly();
669 setSectionAlignmentForBundling(getAssembler(), CurSection);
674 this->MCObjectStreamer::FinishImpl();
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::EmitZerofill(MCSection *Section, MCSymbol *Symbol,
686 uint64_t Size, unsigned ByteAlignment,
688 llvm_unreachable("ELF doesn't support this directive");
691 void MCELFStreamer::EmitTBSSSymbol(MCSection *Section, MCSymbol *Symbol,
692 uint64_t Size, unsigned ByteAlignment) {
693 llvm_unreachable("ELF doesn't support this directive");
696 MCStreamer *llvm::createELFStreamer(MCContext &Context,
697 std::unique_ptr<MCAsmBackend> &&MAB,
698 std::unique_ptr<MCObjectWriter> &&OW,
699 std::unique_ptr<MCCodeEmitter> &&CE,
702 new MCELFStreamer(Context, std::move(MAB), std::move(OW), std::move(CE));
704 S->getAssembler().setRelaxAll(true);