1 //===- lib/MC/MCAssembler.cpp - Assembler Backend Implementation ----------===//
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 #define DEBUG_TYPE "assembler"
11 #include "llvm/MC/MCAssembler.h"
12 #include "llvm/MC/MCAsmLayout.h"
13 #include "llvm/MC/MCCodeEmitter.h"
14 #include "llvm/MC/MCExpr.h"
15 #include "llvm/MC/MCObjectWriter.h"
16 #include "llvm/MC/MCSection.h"
17 #include "llvm/MC/MCSymbol.h"
18 #include "llvm/MC/MCValue.h"
19 #include "llvm/MC/MCDwarf.h"
20 #include "llvm/ADT/OwningPtr.h"
21 #include "llvm/ADT/Statistic.h"
22 #include "llvm/ADT/StringExtras.h"
23 #include "llvm/ADT/Twine.h"
24 #include "llvm/Support/Debug.h"
25 #include "llvm/Support/ErrorHandling.h"
26 #include "llvm/Support/raw_ostream.h"
27 #include "llvm/Target/TargetRegistry.h"
28 #include "llvm/Target/TargetAsmBackend.h"
35 STATISTIC(EmittedFragments, "Number of emitted assembler fragments");
36 STATISTIC(EvaluateFixup, "Number of evaluated fixups");
37 STATISTIC(FragmentLayouts, "Number of fragment layouts");
38 STATISTIC(ObjectBytes, "Number of emitted object file bytes");
39 STATISTIC(RelaxationSteps, "Number of assembler layout and relaxation steps");
40 STATISTIC(RelaxedInstructions, "Number of relaxed instructions");
44 // FIXME FIXME FIXME: There are number of places in this file where we convert
45 // what is a 64-bit assembler value used for computation into a value in the
46 // object file, which may truncate it. We should detect that truncation where
47 // invalid and report errors back.
51 MCAsmLayout::MCAsmLayout(MCAssembler &Asm)
52 : Assembler(Asm), LastValidFragment()
54 // Compute the section layout order. Virtual sections must go last.
55 for (MCAssembler::iterator it = Asm.begin(), ie = Asm.end(); it != ie; ++it)
56 if (!it->getSection().isVirtualSection())
57 SectionOrder.push_back(&*it);
58 for (MCAssembler::iterator it = Asm.begin(), ie = Asm.end(); it != ie; ++it)
59 if (it->getSection().isVirtualSection())
60 SectionOrder.push_back(&*it);
63 bool MCAsmLayout::isFragmentUpToDate(const MCFragment *F) const {
64 const MCSectionData &SD = *F->getParent();
65 const MCFragment *LastValid = LastValidFragment.lookup(&SD);
68 assert(LastValid->getParent() == F->getParent());
69 return F->getLayoutOrder() <= LastValid->getLayoutOrder();
72 void MCAsmLayout::Invalidate(MCFragment *F) {
73 // If this fragment wasn't already up-to-date, we don't need to do anything.
74 if (!isFragmentUpToDate(F))
77 // Otherwise, reset the last valid fragment to this fragment.
78 const MCSectionData &SD = *F->getParent();
79 LastValidFragment[&SD] = F;
82 void MCAsmLayout::EnsureValid(const MCFragment *F) const {
83 MCSectionData &SD = *F->getParent();
85 MCFragment *Cur = LastValidFragment[&SD];
89 Cur = Cur->getNextNode();
91 // Advance the layout position until the fragment is up-to-date.
92 while (!isFragmentUpToDate(F)) {
93 const_cast<MCAsmLayout*>(this)->LayoutFragment(Cur);
94 Cur = Cur->getNextNode();
98 uint64_t MCAsmLayout::getFragmentOffset(const MCFragment *F) const {
100 assert(F->Offset != ~UINT64_C(0) && "Address not set!");
104 uint64_t MCAsmLayout::getSymbolOffset(const MCSymbolData *SD) const {
105 assert(SD->getFragment() && "Invalid getOffset() on undefined symbol!");
106 return getFragmentOffset(SD->getFragment()) + SD->getOffset();
109 uint64_t MCAsmLayout::getSectionAddressSize(const MCSectionData *SD) const {
110 // The size is the last fragment's end offset.
111 const MCFragment &F = SD->getFragmentList().back();
112 return getFragmentOffset(&F) + getAssembler().ComputeFragmentSize(*this, F);
115 uint64_t MCAsmLayout::getSectionFileSize(const MCSectionData *SD) const {
116 // Virtual sections have no file size.
117 if (SD->getSection().isVirtualSection())
120 // Otherwise, the file size is the same as the address space size.
121 return getSectionAddressSize(SD);
126 MCFragment::MCFragment() : Kind(FragmentType(~0)) {
129 MCFragment::~MCFragment() {
132 MCFragment::MCFragment(FragmentType _Kind, MCSectionData *_Parent)
133 : Kind(_Kind), Parent(_Parent), Atom(0), Offset(~UINT64_C(0))
136 Parent->getFragmentList().push_back(this);
141 MCSectionData::MCSectionData() : Section(0) {}
143 MCSectionData::MCSectionData(const MCSection &_Section, MCAssembler *A)
144 : Section(&_Section),
145 Ordinal(~UINT32_C(0)),
147 HasInstructions(false)
150 A->getSectionList().push_back(this);
155 MCSymbolData::MCSymbolData() : Symbol(0) {}
157 MCSymbolData::MCSymbolData(const MCSymbol &_Symbol, MCFragment *_Fragment,
158 uint64_t _Offset, MCAssembler *A)
159 : Symbol(&_Symbol), Fragment(_Fragment), Offset(_Offset),
160 IsExternal(false), IsPrivateExtern(false),
161 CommonSize(0), SymbolSize(0), CommonAlign(0),
165 A->getSymbolList().push_back(this);
170 MCAssembler::MCAssembler(MCContext &Context_, TargetAsmBackend &Backend_,
171 MCCodeEmitter &Emitter_, MCObjectWriter &Writer_,
173 : Context(Context_), Backend(Backend_), Emitter(Emitter_), Writer(Writer_),
174 OS(OS_), RelaxAll(false), SubsectionsViaSymbols(false)
178 MCAssembler::~MCAssembler() {
181 bool MCAssembler::isSymbolLinkerVisible(const MCSymbol &Symbol) const {
182 // Non-temporary labels should always be visible to the linker.
183 if (!Symbol.isTemporary())
186 // Absolute temporary labels are never visible.
187 if (!Symbol.isInSection())
190 // Otherwise, check if the section requires symbols even for temporary labels.
191 return getBackend().doesSectionRequireSymbols(Symbol.getSection());
194 const MCSymbolData *MCAssembler::getAtom(const MCSymbolData *SD) const {
195 // Linker visible symbols define atoms.
196 if (isSymbolLinkerVisible(SD->getSymbol()))
199 // Absolute and undefined symbols have no defining atom.
200 if (!SD->getFragment())
203 // Non-linker visible symbols in sections which can't be atomized have no
205 if (!getBackend().isSectionAtomizable(
206 SD->getFragment()->getParent()->getSection()))
209 // Otherwise, return the atom for the containing fragment.
210 return SD->getFragment()->getAtom();
213 bool MCAssembler::EvaluateFixup(const MCAsmLayout &Layout,
214 const MCFixup &Fixup, const MCFragment *DF,
215 MCValue &Target, uint64_t &Value) const {
216 ++stats::EvaluateFixup;
218 if (!Fixup.getValue()->EvaluateAsRelocatable(Target, &Layout))
219 report_fatal_error("expected relocatable expression");
221 // FIXME: How do non-scattered symbols work in ELF? I presume the linker
222 // doesn't support small relocations, but then under what criteria does the
223 // assembler allow symbol differences?
225 Value = Target.getConstant();
227 bool IsPCRel = Backend.getFixupKindInfo(
228 Fixup.getKind()).Flags & MCFixupKindInfo::FKF_IsPCRel;
229 bool IsResolved = true;
230 bool IsThumb = false;
231 if (const MCSymbolRefExpr *A = Target.getSymA()) {
232 const MCSymbol &Sym = A->getSymbol().AliasedSymbol();
234 Value += Layout.getSymbolOffset(&getSymbolData(Sym));
237 if (isThumbFunc(&Sym))
240 if (const MCSymbolRefExpr *B = Target.getSymB()) {
241 const MCSymbol &Sym = B->getSymbol().AliasedSymbol();
243 Value -= Layout.getSymbolOffset(&getSymbolData(Sym));
249 IsResolved = getWriter().IsFixupFullyResolved(*this, Target, IsPCRel, DF);
251 bool ShouldAlignPC = Backend.getFixupKindInfo(Fixup.getKind()).Flags &
252 MCFixupKindInfo::FKF_IsAlignedDownTo32Bits;
253 assert((ShouldAlignPC ? IsPCRel : true) &&
254 "FKF_IsAlignedDownTo32Bits is only allowed on PC-relative fixups!");
257 uint32_t Offset = Layout.getFragmentOffset(DF) + Fixup.getOffset();
259 // A number of ARM fixups in Thumb mode require that the effective PC
260 // address be determined as the 32-bit aligned version of the actual offset.
261 if (ShouldAlignPC) Offset &= ~0x3;
265 // ARM fixups based from a thumb function address need to have the low
266 // bit set. The actual value is always at least 16-bit aligned, so the
267 // low bit is normally clear and available for use as an ISA flag for
275 uint64_t MCAssembler::ComputeFragmentSize(const MCAsmLayout &Layout,
276 const MCFragment &F) const {
277 switch (F.getKind()) {
278 case MCFragment::FT_Data:
279 return cast<MCDataFragment>(F).getContents().size();
280 case MCFragment::FT_Fill:
281 return cast<MCFillFragment>(F).getSize();
282 case MCFragment::FT_Inst:
283 return cast<MCInstFragment>(F).getInstSize();
285 case MCFragment::FT_LEB:
286 return cast<MCLEBFragment>(F).getContents().size();
288 case MCFragment::FT_Align: {
289 const MCAlignFragment &AF = cast<MCAlignFragment>(F);
290 unsigned Offset = Layout.getFragmentOffset(&AF);
291 unsigned Size = OffsetToAlignment(Offset, AF.getAlignment());
292 if (Size > AF.getMaxBytesToEmit())
297 case MCFragment::FT_Org: {
298 MCOrgFragment &OF = cast<MCOrgFragment>(F);
299 int64_t TargetLocation;
300 if (!OF.getOffset().EvaluateAsAbsolute(TargetLocation, Layout))
301 report_fatal_error("expected assembly-time absolute expression");
303 // FIXME: We need a way to communicate this error.
304 uint64_t FragmentOffset = Layout.getFragmentOffset(&OF);
305 int64_t Size = TargetLocation - FragmentOffset;
306 if (Size < 0 || Size >= 0x40000000)
307 report_fatal_error("invalid .org offset '" + Twine(TargetLocation) +
308 "' (at offset '" + Twine(FragmentOffset) + "')");
312 case MCFragment::FT_Dwarf:
313 return cast<MCDwarfLineAddrFragment>(F).getContents().size();
316 assert(0 && "invalid fragment kind");
320 void MCAsmLayout::LayoutFragment(MCFragment *F) {
321 MCFragment *Prev = F->getPrevNode();
323 // We should never try to recompute something which is up-to-date.
324 assert(!isFragmentUpToDate(F) && "Attempt to recompute up-to-date fragment!");
325 // We should never try to compute the fragment layout if it's predecessor
327 assert((!Prev || isFragmentUpToDate(Prev)) &&
328 "Attempt to compute fragment before it's predecessor!");
330 ++stats::FragmentLayouts;
332 // Compute fragment offset and size.
335 Offset += Prev->Offset + getAssembler().ComputeFragmentSize(*this, *Prev);
338 LastValidFragment[F->getParent()] = F;
341 /// WriteFragmentData - Write the \arg F data to the output file.
342 static void WriteFragmentData(const MCAssembler &Asm, const MCAsmLayout &Layout,
343 const MCFragment &F) {
344 MCObjectWriter *OW = &Asm.getWriter();
345 uint64_t Start = OW->getStream().tell();
348 ++stats::EmittedFragments;
350 // FIXME: Embed in fragments instead?
351 uint64_t FragmentSize = Asm.ComputeFragmentSize(Layout, F);
352 switch (F.getKind()) {
353 case MCFragment::FT_Align: {
354 MCAlignFragment &AF = cast<MCAlignFragment>(F);
355 uint64_t Count = FragmentSize / AF.getValueSize();
357 assert(AF.getValueSize() && "Invalid virtual align in concrete fragment!");
359 // FIXME: This error shouldn't actually occur (the front end should emit
360 // multiple .align directives to enforce the semantics it wants), but is
361 // severe enough that we want to report it. How to handle this?
362 if (Count * AF.getValueSize() != FragmentSize)
363 report_fatal_error("undefined .align directive, value size '" +
364 Twine(AF.getValueSize()) +
365 "' is not a divisor of padding size '" +
366 Twine(FragmentSize) + "'");
368 // See if we are aligning with nops, and if so do that first to try to fill
369 // the Count bytes. Then if that did not fill any bytes or there are any
370 // bytes left to fill use the the Value and ValueSize to fill the rest.
371 // If we are aligning with nops, ask that target to emit the right data.
372 if (AF.hasEmitNops()) {
373 if (!Asm.getBackend().WriteNopData(Count, OW))
374 report_fatal_error("unable to write nop sequence of " +
375 Twine(Count) + " bytes");
379 // Otherwise, write out in multiples of the value size.
380 for (uint64_t i = 0; i != Count; ++i) {
381 switch (AF.getValueSize()) {
383 assert(0 && "Invalid size!");
384 case 1: OW->Write8 (uint8_t (AF.getValue())); break;
385 case 2: OW->Write16(uint16_t(AF.getValue())); break;
386 case 4: OW->Write32(uint32_t(AF.getValue())); break;
387 case 8: OW->Write64(uint64_t(AF.getValue())); break;
393 case MCFragment::FT_Data: {
394 MCDataFragment &DF = cast<MCDataFragment>(F);
395 assert(FragmentSize == DF.getContents().size() && "Invalid size!");
396 OW->WriteBytes(DF.getContents().str());
400 case MCFragment::FT_Fill: {
401 MCFillFragment &FF = cast<MCFillFragment>(F);
403 assert(FF.getValueSize() && "Invalid virtual align in concrete fragment!");
405 for (uint64_t i = 0, e = FF.getSize() / FF.getValueSize(); i != e; ++i) {
406 switch (FF.getValueSize()) {
408 assert(0 && "Invalid size!");
409 case 1: OW->Write8 (uint8_t (FF.getValue())); break;
410 case 2: OW->Write16(uint16_t(FF.getValue())); break;
411 case 4: OW->Write32(uint32_t(FF.getValue())); break;
412 case 8: OW->Write64(uint64_t(FF.getValue())); break;
418 case MCFragment::FT_Inst: {
419 MCInstFragment &IF = cast<MCInstFragment>(F);
420 OW->WriteBytes(StringRef(IF.getCode().begin(), IF.getCode().size()));
424 case MCFragment::FT_LEB: {
425 MCLEBFragment &LF = cast<MCLEBFragment>(F);
426 OW->WriteBytes(LF.getContents().str());
430 case MCFragment::FT_Org: {
431 MCOrgFragment &OF = cast<MCOrgFragment>(F);
433 for (uint64_t i = 0, e = FragmentSize; i != e; ++i)
434 OW->Write8(uint8_t(OF.getValue()));
439 case MCFragment::FT_Dwarf: {
440 const MCDwarfLineAddrFragment &OF = cast<MCDwarfLineAddrFragment>(F);
441 OW->WriteBytes(OF.getContents().str());
446 assert(OW->getStream().tell() - Start == FragmentSize);
449 void MCAssembler::WriteSectionData(const MCSectionData *SD,
450 const MCAsmLayout &Layout) const {
451 // Ignore virtual sections.
452 if (SD->getSection().isVirtualSection()) {
453 assert(Layout.getSectionFileSize(SD) == 0 && "Invalid size for section!");
455 // Check that contents are only things legal inside a virtual section.
456 for (MCSectionData::const_iterator it = SD->begin(),
457 ie = SD->end(); it != ie; ++it) {
458 switch (it->getKind()) {
460 assert(0 && "Invalid fragment in virtual section!");
461 case MCFragment::FT_Data: {
462 // Check that we aren't trying to write a non-zero contents (or fixups)
463 // into a virtual section. This is to support clients which use standard
464 // directives to fill the contents of virtual sections.
465 MCDataFragment &DF = cast<MCDataFragment>(*it);
466 assert(DF.fixup_begin() == DF.fixup_end() &&
467 "Cannot have fixups in virtual section!");
468 for (unsigned i = 0, e = DF.getContents().size(); i != e; ++i)
469 assert(DF.getContents()[i] == 0 &&
470 "Invalid data value for virtual section!");
473 case MCFragment::FT_Align:
474 // Check that we aren't trying to write a non-zero value into a virtual
476 assert((!cast<MCAlignFragment>(it)->getValueSize() ||
477 !cast<MCAlignFragment>(it)->getValue()) &&
478 "Invalid align in virtual section!");
480 case MCFragment::FT_Fill:
481 assert(!cast<MCFillFragment>(it)->getValueSize() &&
482 "Invalid fill in virtual section!");
490 uint64_t Start = getWriter().getStream().tell();
493 for (MCSectionData::const_iterator it = SD->begin(),
494 ie = SD->end(); it != ie; ++it)
495 WriteFragmentData(*this, Layout, *it);
497 assert(getWriter().getStream().tell() - Start ==
498 Layout.getSectionAddressSize(SD));
502 uint64_t MCAssembler::HandleFixup(const MCAsmLayout &Layout,
504 const MCFixup &Fixup) {
505 // Evaluate the fixup.
508 if (!EvaluateFixup(Layout, Fixup, &F, Target, FixedValue)) {
509 // The fixup was unresolved, we need a relocation. Inform the object
510 // writer of the relocation, and give it an opportunity to adjust the
511 // fixup value if need be.
512 getWriter().RecordRelocation(*this, Layout, &F, Fixup, Target, FixedValue);
517 void MCAssembler::Finish() {
518 DEBUG_WITH_TYPE("mc-dump", {
519 llvm::errs() << "assembler backend - pre-layout\n--\n";
522 // Create the layout object.
523 MCAsmLayout Layout(*this);
525 // Create dummy fragments and assign section ordinals.
526 unsigned SectionIndex = 0;
527 for (MCAssembler::iterator it = begin(), ie = end(); it != ie; ++it) {
528 // Create dummy fragments to eliminate any empty sections, this simplifies
530 if (it->getFragmentList().empty())
531 new MCDataFragment(it);
533 it->setOrdinal(SectionIndex++);
536 // Assign layout order indices to sections and fragments.
537 for (unsigned i = 0, e = Layout.getSectionOrder().size(); i != e; ++i) {
538 MCSectionData *SD = Layout.getSectionOrder()[i];
539 SD->setLayoutOrder(i);
541 unsigned FragmentIndex = 0;
542 for (MCSectionData::iterator it2 = SD->begin(),
543 ie2 = SD->end(); it2 != ie2; ++it2)
544 it2->setLayoutOrder(FragmentIndex++);
547 // Layout until everything fits.
548 while (LayoutOnce(Layout))
551 DEBUG_WITH_TYPE("mc-dump", {
552 llvm::errs() << "assembler backend - post-relaxation\n--\n";
555 // Finalize the layout, including fragment lowering.
556 FinishLayout(Layout);
558 DEBUG_WITH_TYPE("mc-dump", {
559 llvm::errs() << "assembler backend - final-layout\n--\n";
562 uint64_t StartOffset = OS.tell();
564 // Allow the object writer a chance to perform post-layout binding (for
565 // example, to set the index fields in the symbol data).
566 getWriter().ExecutePostLayoutBinding(*this, Layout);
568 // Evaluate and apply the fixups, generating relocation entries as necessary.
569 for (MCAssembler::iterator it = begin(), ie = end(); it != ie; ++it) {
570 for (MCSectionData::iterator it2 = it->begin(),
571 ie2 = it->end(); it2 != ie2; ++it2) {
572 MCDataFragment *DF = dyn_cast<MCDataFragment>(it2);
574 for (MCDataFragment::fixup_iterator it3 = DF->fixup_begin(),
575 ie3 = DF->fixup_end(); it3 != ie3; ++it3) {
576 MCFixup &Fixup = *it3;
577 uint64_t FixedValue = HandleFixup(Layout, *DF, Fixup);
578 getBackend().ApplyFixup(Fixup, DF->getContents().data(),
579 DF->getContents().size(), FixedValue);
582 MCInstFragment *IF = dyn_cast<MCInstFragment>(it2);
584 for (MCInstFragment::fixup_iterator it3 = IF->fixup_begin(),
585 ie3 = IF->fixup_end(); it3 != ie3; ++it3) {
586 MCFixup &Fixup = *it3;
587 uint64_t FixedValue = HandleFixup(Layout, *IF, Fixup);
588 getBackend().ApplyFixup(Fixup, IF->getCode().data(),
589 IF->getCode().size(), FixedValue);
595 // Write the object file.
596 getWriter().WriteObject(*this, Layout);
598 stats::ObjectBytes += OS.tell() - StartOffset;
601 bool MCAssembler::FixupNeedsRelaxation(const MCFixup &Fixup,
602 const MCFragment *DF,
603 const MCAsmLayout &Layout) const {
607 // If we cannot resolve the fixup value, it requires relaxation.
610 if (!EvaluateFixup(Layout, Fixup, DF, Target, Value))
613 // Otherwise, relax if the value is too big for a (signed) i8.
615 // FIXME: This is target dependent!
616 return int64_t(Value) != int64_t(int8_t(Value));
619 bool MCAssembler::FragmentNeedsRelaxation(const MCInstFragment *IF,
620 const MCAsmLayout &Layout) const {
621 // If this inst doesn't ever need relaxation, ignore it. This occurs when we
622 // are intentionally pushing out inst fragments, or because we relaxed a
623 // previous instruction to one that doesn't need relaxation.
624 if (!getBackend().MayNeedRelaxation(IF->getInst()))
627 for (MCInstFragment::const_fixup_iterator it = IF->fixup_begin(),
628 ie = IF->fixup_end(); it != ie; ++it)
629 if (FixupNeedsRelaxation(*it, IF, Layout))
635 bool MCAssembler::RelaxInstruction(MCAsmLayout &Layout,
636 MCInstFragment &IF) {
637 if (!FragmentNeedsRelaxation(&IF, Layout))
640 ++stats::RelaxedInstructions;
642 // FIXME-PERF: We could immediately lower out instructions if we can tell
643 // they are fully resolved, to avoid retesting on later passes.
645 // Relax the fragment.
648 getBackend().RelaxInstruction(IF.getInst(), Relaxed);
650 // Encode the new instruction.
652 // FIXME-PERF: If it matters, we could let the target do this. It can
653 // probably do so more efficiently in many cases.
654 SmallVector<MCFixup, 4> Fixups;
655 SmallString<256> Code;
656 raw_svector_ostream VecOS(Code);
657 getEmitter().EncodeInstruction(Relaxed, VecOS, Fixups);
660 // Update the instruction fragment.
663 IF.getFixups().clear();
664 // FIXME: Eliminate copy.
665 for (unsigned i = 0, e = Fixups.size(); i != e; ++i)
666 IF.getFixups().push_back(Fixups[i]);
671 bool MCAssembler::RelaxLEB(MCAsmLayout &Layout, MCLEBFragment &LF) {
673 uint64_t OldSize = LF.getContents().size();
674 LF.getValue().EvaluateAsAbsolute(Value, Layout);
675 SmallString<8> &Data = LF.getContents();
677 raw_svector_ostream OSE(Data);
679 MCObjectWriter::EncodeSLEB128(Value, OSE);
681 MCObjectWriter::EncodeULEB128(Value, OSE);
683 return OldSize != LF.getContents().size();
686 bool MCAssembler::RelaxDwarfLineAddr(MCAsmLayout &Layout,
687 MCDwarfLineAddrFragment &DF) {
688 int64_t AddrDelta = 0;
689 uint64_t OldSize = DF.getContents().size();
690 DF.getAddrDelta().EvaluateAsAbsolute(AddrDelta, Layout);
692 LineDelta = DF.getLineDelta();
693 SmallString<8> &Data = DF.getContents();
695 raw_svector_ostream OSE(Data);
696 MCDwarfLineAddr::Encode(LineDelta, AddrDelta, OSE);
698 return OldSize != Data.size();
701 bool MCAssembler::LayoutSectionOnce(MCAsmLayout &Layout,
703 MCFragment *FirstInvalidFragment = NULL;
704 // Scan for fragments that need relaxation.
705 for (MCSectionData::iterator it2 = SD.begin(),
706 ie2 = SD.end(); it2 != ie2; ++it2) {
707 // Check if this is an fragment that needs relaxation.
708 bool relaxedFrag = false;
709 switch(it2->getKind()) {
712 case MCFragment::FT_Inst:
713 relaxedFrag = RelaxInstruction(Layout, *cast<MCInstFragment>(it2));
715 case MCFragment::FT_Dwarf:
716 relaxedFrag = RelaxDwarfLineAddr(Layout,
717 *cast<MCDwarfLineAddrFragment>(it2));
719 case MCFragment::FT_LEB:
720 relaxedFrag = RelaxLEB(Layout, *cast<MCLEBFragment>(it2));
723 // Update the layout, and remember that we relaxed.
724 if (relaxedFrag && !FirstInvalidFragment)
725 FirstInvalidFragment = it2;
727 if (FirstInvalidFragment) {
728 Layout.Invalidate(FirstInvalidFragment);
734 bool MCAssembler::LayoutOnce(MCAsmLayout &Layout) {
735 ++stats::RelaxationSteps;
737 bool WasRelaxed = false;
738 for (iterator it = begin(), ie = end(); it != ie; ++it) {
739 MCSectionData &SD = *it;
740 while(LayoutSectionOnce(Layout, SD))
747 void MCAssembler::FinishLayout(MCAsmLayout &Layout) {
748 // The layout is done. Mark every fragment as valid.
749 for (unsigned int i = 0, n = Layout.getSectionOrder().size(); i != n; ++i) {
750 Layout.getFragmentOffset(&*Layout.getSectionOrder()[i]->rbegin());
758 raw_ostream &operator<<(raw_ostream &OS, const MCFixup &AF) {
759 OS << "<MCFixup" << " Offset:" << AF.getOffset()
760 << " Value:" << *AF.getValue()
761 << " Kind:" << AF.getKind() << ">";
767 void MCFragment::dump() {
768 raw_ostream &OS = llvm::errs();
772 case MCFragment::FT_Align: OS << "MCAlignFragment"; break;
773 case MCFragment::FT_Data: OS << "MCDataFragment"; break;
774 case MCFragment::FT_Fill: OS << "MCFillFragment"; break;
775 case MCFragment::FT_Inst: OS << "MCInstFragment"; break;
776 case MCFragment::FT_Org: OS << "MCOrgFragment"; break;
777 case MCFragment::FT_Dwarf: OS << "MCDwarfFragment"; break;
778 case MCFragment::FT_LEB: OS << "MCLEBFragment"; break;
781 OS << "<MCFragment " << (void*) this << " LayoutOrder:" << LayoutOrder
782 << " Offset:" << Offset << ">";
785 case MCFragment::FT_Align: {
786 const MCAlignFragment *AF = cast<MCAlignFragment>(this);
787 if (AF->hasEmitNops())
788 OS << " (emit nops)";
790 OS << " Alignment:" << AF->getAlignment()
791 << " Value:" << AF->getValue() << " ValueSize:" << AF->getValueSize()
792 << " MaxBytesToEmit:" << AF->getMaxBytesToEmit() << ">";
795 case MCFragment::FT_Data: {
796 const MCDataFragment *DF = cast<MCDataFragment>(this);
799 const SmallVectorImpl<char> &Contents = DF->getContents();
800 for (unsigned i = 0, e = Contents.size(); i != e; ++i) {
802 OS << hexdigit((Contents[i] >> 4) & 0xF) << hexdigit(Contents[i] & 0xF);
804 OS << "] (" << Contents.size() << " bytes)";
806 if (!DF->getFixups().empty()) {
809 for (MCDataFragment::const_fixup_iterator it = DF->fixup_begin(),
810 ie = DF->fixup_end(); it != ie; ++it) {
811 if (it != DF->fixup_begin()) OS << ",\n ";
818 case MCFragment::FT_Fill: {
819 const MCFillFragment *FF = cast<MCFillFragment>(this);
820 OS << " Value:" << FF->getValue() << " ValueSize:" << FF->getValueSize()
821 << " Size:" << FF->getSize();
824 case MCFragment::FT_Inst: {
825 const MCInstFragment *IF = cast<MCInstFragment>(this);
828 IF->getInst().dump_pretty(OS);
831 case MCFragment::FT_Org: {
832 const MCOrgFragment *OF = cast<MCOrgFragment>(this);
834 OS << " Offset:" << OF->getOffset() << " Value:" << OF->getValue();
837 case MCFragment::FT_Dwarf: {
838 const MCDwarfLineAddrFragment *OF = cast<MCDwarfLineAddrFragment>(this);
840 OS << " AddrDelta:" << OF->getAddrDelta()
841 << " LineDelta:" << OF->getLineDelta();
844 case MCFragment::FT_LEB: {
845 const MCLEBFragment *LF = cast<MCLEBFragment>(this);
847 OS << " Value:" << LF->getValue() << " Signed:" << LF->isSigned();
854 void MCSectionData::dump() {
855 raw_ostream &OS = llvm::errs();
857 OS << "<MCSectionData";
858 OS << " Alignment:" << getAlignment() << " Fragments:[\n ";
859 for (iterator it = begin(), ie = end(); it != ie; ++it) {
860 if (it != begin()) OS << ",\n ";
866 void MCSymbolData::dump() {
867 raw_ostream &OS = llvm::errs();
869 OS << "<MCSymbolData Symbol:" << getSymbol()
870 << " Fragment:" << getFragment() << " Offset:" << getOffset()
871 << " Flags:" << getFlags() << " Index:" << getIndex();
873 OS << " (common, size:" << getCommonSize()
874 << " align: " << getCommonAlignment() << ")";
877 if (isPrivateExtern())
878 OS << " (private extern)";
882 void MCAssembler::dump() {
883 raw_ostream &OS = llvm::errs();
885 OS << "<MCAssembler\n";
886 OS << " Sections:[\n ";
887 for (iterator it = begin(), ie = end(); it != ie; ++it) {
888 if (it != begin()) OS << ",\n ";
894 for (symbol_iterator it = symbol_begin(), ie = symbol_end(); it != ie; ++it) {
895 if (it != symbol_begin()) OS << ",\n ";