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 getCurrentSectionData()->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 = getAssembler().getSymbolData(*Symbol);
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 = getCurrentSectionData();
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 MCSymbol *SectionSymbol = getContext().getOrCreateSectionSymbol(*SectionELF);
163 if (SectionSymbol->isUndefined()) {
164 EmitLabel(SectionSymbol);
165 MCELF::SetType(Asm.getSymbolData(*SectionSymbol), ELF::STT_SECTION);
169 void MCELFStreamer::EmitWeakReference(MCSymbol *Alias, const MCSymbol *Symbol) {
170 getAssembler().getOrCreateSymbolData(*Symbol);
171 const MCExpr *Value = MCSymbolRefExpr::Create(
172 Symbol, MCSymbolRefExpr::VK_WEAKREF, getContext());
173 Alias->setVariableValue(Value);
176 // When GNU as encounters more than one .type declaration for an object it seems
177 // to use a mechanism similar to the one below to decide which type is actually
178 // used in the object file. The greater of T1 and T2 is selected based on the
179 // following ordering:
180 // STT_NOTYPE < STT_OBJECT < STT_FUNC < STT_GNU_IFUNC < STT_TLS < anything else
181 // If neither T1 < T2 nor T2 < T1 according to this ordering, use T2 (the user
183 static unsigned CombineSymbolTypes(unsigned T1, unsigned T2) {
184 for (unsigned Type : {ELF::STT_NOTYPE, ELF::STT_OBJECT, ELF::STT_FUNC,
185 ELF::STT_GNU_IFUNC, ELF::STT_TLS}) {
195 bool MCELFStreamer::EmitSymbolAttribute(MCSymbol *Symbol,
196 MCSymbolAttr Attribute) {
197 // Indirect symbols are handled differently, to match how 'as' handles
198 // them. This makes writing matching .o files easier.
199 if (Attribute == MCSA_IndirectSymbol) {
200 // Note that we intentionally cannot use the symbol data here; this is
201 // important for matching the string table that 'as' generates.
202 IndirectSymbolData ISD;
204 ISD.Section = getCurrentSectionData();
205 getAssembler().getIndirectSymbols().push_back(ISD);
209 // Adding a symbol attribute always introduces the symbol, note that an
210 // important side effect of calling getOrCreateSymbolData here is to register
211 // the symbol with the assembler.
212 MCSymbolData &SD = getAssembler().getOrCreateSymbolData(*Symbol);
214 // The implementation of symbol attributes is designed to match 'as', but it
215 // leaves much to desired. It doesn't really make sense to arbitrarily add and
216 // remove flags, but 'as' allows this (in particular, see .desc).
218 // In the future it might be worth trying to make these operations more well
221 case MCSA_LazyReference:
223 case MCSA_SymbolResolver:
224 case MCSA_PrivateExtern:
225 case MCSA_WeakDefinition:
226 case MCSA_WeakDefAutoPrivate:
228 case MCSA_IndirectSymbol:
231 case MCSA_NoDeadStrip:
235 case MCSA_ELF_TypeGnuUniqueObject:
236 MCELF::SetType(SD, CombineSymbolTypes(MCELF::GetType(SD), ELF::STT_OBJECT));
237 MCELF::SetBinding(SD, ELF::STB_GNU_UNIQUE);
238 SD.setExternal(true);
239 BindingExplicitlySet.insert(Symbol);
243 MCELF::SetBinding(SD, ELF::STB_GLOBAL);
244 SD.setExternal(true);
245 BindingExplicitlySet.insert(Symbol);
248 case MCSA_WeakReference:
250 MCELF::SetBinding(SD, ELF::STB_WEAK);
251 SD.setExternal(true);
252 BindingExplicitlySet.insert(Symbol);
256 MCELF::SetBinding(SD, ELF::STB_LOCAL);
257 SD.setExternal(false);
258 BindingExplicitlySet.insert(Symbol);
261 case MCSA_ELF_TypeFunction:
262 MCELF::SetType(SD, CombineSymbolTypes(MCELF::GetType(SD),
266 case MCSA_ELF_TypeIndFunction:
267 MCELF::SetType(SD, CombineSymbolTypes(MCELF::GetType(SD),
268 ELF::STT_GNU_IFUNC));
271 case MCSA_ELF_TypeObject:
272 MCELF::SetType(SD, CombineSymbolTypes(MCELF::GetType(SD),
276 case MCSA_ELF_TypeTLS:
277 MCELF::SetType(SD, CombineSymbolTypes(MCELF::GetType(SD),
281 case MCSA_ELF_TypeCommon:
282 // TODO: Emit these as a common symbol.
283 MCELF::SetType(SD, CombineSymbolTypes(MCELF::GetType(SD),
287 case MCSA_ELF_TypeNoType:
288 MCELF::SetType(SD, CombineSymbolTypes(MCELF::GetType(SD),
293 MCELF::SetVisibility(SD, ELF::STV_PROTECTED);
297 MCELF::SetVisibility(SD, ELF::STV_HIDDEN);
301 MCELF::SetVisibility(SD, ELF::STV_INTERNAL);
308 void MCELFStreamer::EmitCommonSymbol(MCSymbol *Symbol, uint64_t Size,
309 unsigned ByteAlignment) {
310 MCSymbolData &SD = getAssembler().getOrCreateSymbolData(*Symbol);
312 if (!BindingExplicitlySet.count(Symbol)) {
313 MCELF::SetBinding(SD, ELF::STB_GLOBAL);
314 SD.setExternal(true);
317 MCELF::SetType(SD, ELF::STT_OBJECT);
319 if (MCELF::GetBinding(SD) == ELF_STB_Local) {
320 MCSection *Section = getAssembler().getContext().getELFSection(
321 ".bss", ELF::SHT_NOBITS, ELF::SHF_WRITE | ELF::SHF_ALLOC);
323 AssignSection(Symbol, Section);
325 struct LocalCommon L = {Symbol, Size, ByteAlignment};
326 LocalCommons.push_back(L);
328 SD.setCommon(Size, ByteAlignment);
331 SD.setSize(MCConstantExpr::Create(Size, getContext()));
334 void MCELFStreamer::EmitELFSize(MCSymbol *Symbol, const MCExpr *Value) {
335 MCSymbolData &SD = getAssembler().getOrCreateSymbolData(*Symbol);
339 void MCELFStreamer::EmitLocalCommonSymbol(MCSymbol *Symbol, uint64_t Size,
340 unsigned ByteAlignment) {
341 // FIXME: Should this be caught and done earlier?
342 MCSymbolData &SD = getAssembler().getOrCreateSymbolData(*Symbol);
343 MCELF::SetBinding(SD, ELF::STB_LOCAL);
344 SD.setExternal(false);
345 BindingExplicitlySet.insert(Symbol);
346 EmitCommonSymbol(Symbol, Size, ByteAlignment);
349 void MCELFStreamer::EmitValueImpl(const MCExpr *Value, unsigned Size,
351 if (isBundleLocked())
352 report_fatal_error("Emitting values inside a locked bundle is forbidden");
353 fixSymbolsInTLSFixups(Value);
354 MCObjectStreamer::EmitValueImpl(Value, Size, Loc);
357 void MCELFStreamer::EmitValueToAlignment(unsigned ByteAlignment,
360 unsigned MaxBytesToEmit) {
361 if (isBundleLocked())
362 report_fatal_error("Emitting values inside a locked bundle is forbidden");
363 MCObjectStreamer::EmitValueToAlignment(ByteAlignment, Value,
364 ValueSize, MaxBytesToEmit);
367 // Add a symbol for the file name of this module. They start after the
368 // null symbol and don't count as normal symbol, i.e. a non-STT_FILE symbol
369 // with the same name may appear.
370 void MCELFStreamer::EmitFileDirective(StringRef Filename) {
371 getAssembler().addFileName(Filename);
374 void MCELFStreamer::EmitIdent(StringRef IdentString) {
375 MCSection *Comment = getAssembler().getContext().getELFSection(
376 ".comment", ELF::SHT_PROGBITS, ELF::SHF_MERGE | ELF::SHF_STRINGS, 1, "");
378 SwitchSection(Comment);
383 EmitBytes(IdentString);
388 void MCELFStreamer::fixSymbolsInTLSFixups(const MCExpr *expr) {
389 switch (expr->getKind()) {
391 cast<MCTargetExpr>(expr)->fixELFSymbolsInTLSFixups(getAssembler());
393 case MCExpr::Constant:
396 case MCExpr::Binary: {
397 const MCBinaryExpr *be = cast<MCBinaryExpr>(expr);
398 fixSymbolsInTLSFixups(be->getLHS());
399 fixSymbolsInTLSFixups(be->getRHS());
403 case MCExpr::SymbolRef: {
404 const MCSymbolRefExpr &symRef = *cast<MCSymbolRefExpr>(expr);
405 switch (symRef.getKind()) {
408 case MCSymbolRefExpr::VK_GOTTPOFF:
409 case MCSymbolRefExpr::VK_INDNTPOFF:
410 case MCSymbolRefExpr::VK_NTPOFF:
411 case MCSymbolRefExpr::VK_GOTNTPOFF:
412 case MCSymbolRefExpr::VK_TLSGD:
413 case MCSymbolRefExpr::VK_TLSLD:
414 case MCSymbolRefExpr::VK_TLSLDM:
415 case MCSymbolRefExpr::VK_TPOFF:
416 case MCSymbolRefExpr::VK_DTPOFF:
417 case MCSymbolRefExpr::VK_Mips_TLSGD:
418 case MCSymbolRefExpr::VK_Mips_GOTTPREL:
419 case MCSymbolRefExpr::VK_Mips_TPREL_HI:
420 case MCSymbolRefExpr::VK_Mips_TPREL_LO:
421 case MCSymbolRefExpr::VK_PPC_DTPMOD:
422 case MCSymbolRefExpr::VK_PPC_TPREL:
423 case MCSymbolRefExpr::VK_PPC_TPREL_LO:
424 case MCSymbolRefExpr::VK_PPC_TPREL_HI:
425 case MCSymbolRefExpr::VK_PPC_TPREL_HA:
426 case MCSymbolRefExpr::VK_PPC_TPREL_HIGHER:
427 case MCSymbolRefExpr::VK_PPC_TPREL_HIGHERA:
428 case MCSymbolRefExpr::VK_PPC_TPREL_HIGHEST:
429 case MCSymbolRefExpr::VK_PPC_TPREL_HIGHESTA:
430 case MCSymbolRefExpr::VK_PPC_DTPREL:
431 case MCSymbolRefExpr::VK_PPC_DTPREL_LO:
432 case MCSymbolRefExpr::VK_PPC_DTPREL_HI:
433 case MCSymbolRefExpr::VK_PPC_DTPREL_HA:
434 case MCSymbolRefExpr::VK_PPC_DTPREL_HIGHER:
435 case MCSymbolRefExpr::VK_PPC_DTPREL_HIGHERA:
436 case MCSymbolRefExpr::VK_PPC_DTPREL_HIGHEST:
437 case MCSymbolRefExpr::VK_PPC_DTPREL_HIGHESTA:
438 case MCSymbolRefExpr::VK_PPC_GOT_TPREL:
439 case MCSymbolRefExpr::VK_PPC_GOT_TPREL_LO:
440 case MCSymbolRefExpr::VK_PPC_GOT_TPREL_HI:
441 case MCSymbolRefExpr::VK_PPC_GOT_TPREL_HA:
442 case MCSymbolRefExpr::VK_PPC_GOT_DTPREL:
443 case MCSymbolRefExpr::VK_PPC_GOT_DTPREL_LO:
444 case MCSymbolRefExpr::VK_PPC_GOT_DTPREL_HI:
445 case MCSymbolRefExpr::VK_PPC_GOT_DTPREL_HA:
446 case MCSymbolRefExpr::VK_PPC_TLS:
447 case MCSymbolRefExpr::VK_PPC_GOT_TLSGD:
448 case MCSymbolRefExpr::VK_PPC_GOT_TLSGD_LO:
449 case MCSymbolRefExpr::VK_PPC_GOT_TLSGD_HI:
450 case MCSymbolRefExpr::VK_PPC_GOT_TLSGD_HA:
451 case MCSymbolRefExpr::VK_PPC_TLSGD:
452 case MCSymbolRefExpr::VK_PPC_GOT_TLSLD:
453 case MCSymbolRefExpr::VK_PPC_GOT_TLSLD_LO:
454 case MCSymbolRefExpr::VK_PPC_GOT_TLSLD_HI:
455 case MCSymbolRefExpr::VK_PPC_GOT_TLSLD_HA:
456 case MCSymbolRefExpr::VK_PPC_TLSLD:
459 MCSymbolData &SD = getAssembler().getOrCreateSymbolData(symRef.getSymbol());
460 MCELF::SetType(SD, ELF::STT_TLS);
465 fixSymbolsInTLSFixups(cast<MCUnaryExpr>(expr)->getSubExpr());
470 void MCELFStreamer::EmitInstToFragment(const MCInst &Inst,
471 const MCSubtargetInfo &STI) {
472 this->MCObjectStreamer::EmitInstToFragment(Inst, STI);
473 MCRelaxableFragment &F = *cast<MCRelaxableFragment>(getCurrentFragment());
475 for (unsigned i = 0, e = F.getFixups().size(); i != e; ++i)
476 fixSymbolsInTLSFixups(F.getFixups()[i].getValue());
479 void MCELFStreamer::EmitInstToData(const MCInst &Inst,
480 const MCSubtargetInfo &STI) {
481 MCAssembler &Assembler = getAssembler();
482 SmallVector<MCFixup, 4> Fixups;
483 SmallString<256> Code;
484 raw_svector_ostream VecOS(Code);
485 Assembler.getEmitter().encodeInstruction(Inst, VecOS, Fixups, STI);
488 for (unsigned i = 0, e = Fixups.size(); i != e; ++i)
489 fixSymbolsInTLSFixups(Fixups[i].getValue());
491 // There are several possibilities here:
493 // If bundling is disabled, append the encoded instruction to the current data
494 // fragment (or create a new such fragment if the current fragment is not a
497 // If bundling is enabled:
498 // - If we're not in a bundle-locked group, emit the instruction into a
499 // fragment of its own. If there are no fixups registered for the
500 // instruction, emit a MCCompactEncodedInstFragment. Otherwise, emit a
502 // - If we're in a bundle-locked group, append the instruction to the current
503 // data fragment because we want all the instructions in a group to get into
504 // the same fragment. Be careful not to do that for the first instruction in
505 // the group, though.
508 if (Assembler.isBundlingEnabled()) {
509 MCSection &Sec = *getCurrentSectionData();
510 if (Assembler.getRelaxAll() && isBundleLocked())
511 // If the -mc-relax-all flag is used and we are bundle-locked, we re-use
512 // the current bundle group.
513 DF = BundleGroups.back();
514 else if (Assembler.getRelaxAll() && !isBundleLocked())
515 // When not in a bundle-locked group and the -mc-relax-all flag is used,
516 // we create a new temporary fragment which will be later merged into
517 // the current fragment.
518 DF = new MCDataFragment();
519 else if (isBundleLocked() && !Sec.isBundleGroupBeforeFirstInst())
520 // If we are bundle-locked, we re-use the current fragment.
521 // The bundle-locking directive ensures this is a new data fragment.
522 DF = cast<MCDataFragment>(getCurrentFragment());
523 else if (!isBundleLocked() && Fixups.size() == 0) {
524 // Optimize memory usage by emitting the instruction to a
525 // MCCompactEncodedInstFragment when not in a bundle-locked group and
526 // there are no fixups registered.
527 MCCompactEncodedInstFragment *CEIF = new MCCompactEncodedInstFragment();
529 CEIF->getContents().append(Code.begin(), Code.end());
532 DF = new MCDataFragment();
535 if (Sec.getBundleLockState() == MCSection::BundleLockedAlignToEnd) {
536 // If this fragment is for a group marked "align_to_end", set a flag
537 // in the fragment. This can happen after the fragment has already been
538 // created if there are nested bundle_align groups and an inner one
539 // is the one marked align_to_end.
540 DF->setAlignToBundleEnd(true);
543 // We're now emitting an instruction in a bundle group, so this flag has
545 Sec.setBundleGroupBeforeFirstInst(false);
547 DF = getOrCreateDataFragment();
550 // Add the fixups and data.
551 for (unsigned i = 0, e = Fixups.size(); i != e; ++i) {
552 Fixups[i].setOffset(Fixups[i].getOffset() + DF->getContents().size());
553 DF->getFixups().push_back(Fixups[i]);
555 DF->setHasInstructions(true);
556 DF->getContents().append(Code.begin(), Code.end());
558 if (Assembler.isBundlingEnabled() && Assembler.getRelaxAll()) {
559 if (!isBundleLocked()) {
560 mergeFragment(getOrCreateDataFragment(), DF);
566 void MCELFStreamer::EmitBundleAlignMode(unsigned AlignPow2) {
567 assert(AlignPow2 <= 30 && "Invalid bundle alignment");
568 MCAssembler &Assembler = getAssembler();
569 if (AlignPow2 > 0 && (Assembler.getBundleAlignSize() == 0 ||
570 Assembler.getBundleAlignSize() == 1U << AlignPow2))
571 Assembler.setBundleAlignSize(1U << AlignPow2);
573 report_fatal_error(".bundle_align_mode cannot be changed once set");
576 void MCELFStreamer::EmitBundleLock(bool AlignToEnd) {
577 MCSection &Sec = *getCurrentSectionData();
581 if (!getAssembler().isBundlingEnabled())
582 report_fatal_error(".bundle_lock forbidden when bundling is disabled");
584 if (!isBundleLocked())
585 Sec.setBundleGroupBeforeFirstInst(true);
587 if (getAssembler().getRelaxAll() && !isBundleLocked()) {
588 // TODO: drop the lock state and set directly in the fragment
589 MCDataFragment *DF = new MCDataFragment();
590 BundleGroups.push_back(DF);
593 Sec.setBundleLockState(AlignToEnd ? MCSection::BundleLockedAlignToEnd
594 : MCSection::BundleLocked);
597 void MCELFStreamer::EmitBundleUnlock() {
598 MCSection &Sec = *getCurrentSectionData();
601 if (!getAssembler().isBundlingEnabled())
602 report_fatal_error(".bundle_unlock forbidden when bundling is disabled");
603 else if (!isBundleLocked())
604 report_fatal_error(".bundle_unlock without matching lock");
605 else if (Sec.isBundleGroupBeforeFirstInst())
606 report_fatal_error("Empty bundle-locked group is forbidden");
608 // When the -mc-relax-all flag is used, we emit instructions to fragments
609 // stored on a stack. When the bundle unlock is emited, we pop a fragment
610 // from the stack a merge it to the one below.
611 if (getAssembler().getRelaxAll()) {
612 assert(!BundleGroups.empty() && "There are no bundle groups");
613 MCDataFragment *DF = BundleGroups.back();
615 // FIXME: Use BundleGroups to track the lock state instead.
616 Sec.setBundleLockState(MCSection::NotBundleLocked);
618 // FIXME: Use more separate fragments for nested groups.
619 if (!isBundleLocked()) {
620 mergeFragment(getOrCreateDataFragment(), DF);
621 BundleGroups.pop_back();
625 if (Sec.getBundleLockState() != MCSection::BundleLockedAlignToEnd)
626 getOrCreateDataFragment()->setAlignToBundleEnd(false);
628 Sec.setBundleLockState(MCSection::NotBundleLocked);
631 void MCELFStreamer::Flush() {
632 for (std::vector<LocalCommon>::const_iterator i = LocalCommons.begin(),
633 e = LocalCommons.end();
635 const MCSymbol &Symbol = *i->Symbol;
636 uint64_t Size = i->Size;
637 unsigned ByteAlignment = i->ByteAlignment;
638 MCSection &Section = Symbol.getSection();
640 MCSectionData &SectData = getAssembler().getOrCreateSectionData(Section);
641 new MCAlignFragment(ByteAlignment, 0, 1, ByteAlignment,
642 &SectData.getSection());
644 MCFragment *F = new MCFillFragment(0, 0, Size, &SectData.getSection());
645 Symbol.getData().setFragment(F);
647 // Update the maximum alignment of the section if necessary.
648 if (ByteAlignment > Section.getAlignment())
649 Section.setAlignment(ByteAlignment);
652 LocalCommons.clear();
655 void MCELFStreamer::FinishImpl() {
656 // Ensure the last section gets aligned if necessary.
657 MCSection *CurSection = getCurrentSectionData();
658 setSectionAlignmentForBundling(getAssembler(), CurSection);
664 this->MCObjectStreamer::FinishImpl();
667 MCStreamer *llvm::createELFStreamer(MCContext &Context, MCAsmBackend &MAB,
668 raw_pwrite_stream &OS, MCCodeEmitter *CE,
670 MCELFStreamer *S = new MCELFStreamer(Context, MAB, OS, CE);
672 S->getAssembler().setRelaxAll(true);
676 void MCELFStreamer::EmitThumbFunc(MCSymbol *Func) {
677 llvm_unreachable("Generic ELF doesn't support this directive");
680 void MCELFStreamer::EmitSymbolDesc(MCSymbol *Symbol, unsigned DescValue) {
681 llvm_unreachable("ELF doesn't support this directive");
684 void MCELFStreamer::BeginCOFFSymbolDef(const MCSymbol *Symbol) {
685 llvm_unreachable("ELF doesn't support this directive");
688 void MCELFStreamer::EmitCOFFSymbolStorageClass(int StorageClass) {
689 llvm_unreachable("ELF doesn't support this directive");
692 void MCELFStreamer::EmitCOFFSymbolType(int Type) {
693 llvm_unreachable("ELF doesn't support this directive");
696 void MCELFStreamer::EndCOFFSymbolDef() {
697 llvm_unreachable("ELF doesn't support this directive");
700 void MCELFStreamer::EmitZerofill(MCSection *Section, MCSymbol *Symbol,
701 uint64_t Size, unsigned ByteAlignment) {
702 llvm_unreachable("ELF doesn't support this directive");
705 void MCELFStreamer::EmitTBSSSymbol(MCSection *Section, MCSymbol *Symbol,
706 uint64_t Size, unsigned ByteAlignment) {
707 llvm_unreachable("ELF doesn't support this directive");