MCAssembler.cpp revision 36b56886974eae4f9c5ebc96befd3e7bfe5de338 
1//===- lib/MC/MCAssembler.cpp - Assembler Backend Implementation ----------===//
2//
3//                     The LLVM Compiler Infrastructure
4//
5// This file is distributed under the University of Illinois Open Source
6// License. See LICENSE.TXT for details.
7//
8//===----------------------------------------------------------------------===//
9
10#define DEBUG_TYPE "assembler"
11#include "llvm/MC/MCAssembler.h"
12#include "llvm/ADT/Statistic.h"
13#include "llvm/ADT/StringExtras.h"
14#include "llvm/ADT/Twine.h"
15#include "llvm/MC/MCAsmBackend.h"
16#include "llvm/MC/MCAsmLayout.h"
17#include "llvm/MC/MCCodeEmitter.h"
18#include "llvm/MC/MCContext.h"
19#include "llvm/MC/MCDwarf.h"
20#include "llvm/MC/MCExpr.h"
21#include "llvm/MC/MCFixupKindInfo.h"
22#include "llvm/MC/MCObjectWriter.h"
23#include "llvm/MC/MCSection.h"
24#include "llvm/MC/MCSymbol.h"
25#include "llvm/MC/MCValue.h"
26#include "llvm/Support/Debug.h"
27#include "llvm/Support/ErrorHandling.h"
28#include "llvm/Support/LEB128.h"
29#include "llvm/Support/TargetRegistry.h"
30#include "llvm/Support/raw_ostream.h"
31#include "llvm/Support/MemoryBuffer.h"
32#include "llvm/Support/Compression.h"
33#include "llvm/Support/Host.h"
34
35using namespace llvm;
36
37namespace {
38namespace stats {
39STATISTIC(EmittedFragments, "Number of emitted assembler fragments - total");
40STATISTIC(EmittedRelaxableFragments,
41          "Number of emitted assembler fragments - relaxable");
42STATISTIC(EmittedDataFragments,
43          "Number of emitted assembler fragments - data");
44STATISTIC(EmittedCompactEncodedInstFragments,
45          "Number of emitted assembler fragments - compact encoded inst");
46STATISTIC(EmittedAlignFragments,
47          "Number of emitted assembler fragments - align");
48STATISTIC(EmittedFillFragments,
49          "Number of emitted assembler fragments - fill");
50STATISTIC(EmittedOrgFragments,
51          "Number of emitted assembler fragments - org");
52STATISTIC(evaluateFixup, "Number of evaluated fixups");
53STATISTIC(FragmentLayouts, "Number of fragment layouts");
54STATISTIC(ObjectBytes, "Number of emitted object file bytes");
55STATISTIC(RelaxationSteps, "Number of assembler layout and relaxation steps");
56STATISTIC(RelaxedInstructions, "Number of relaxed instructions");
57}
58}
59
60// FIXME FIXME FIXME: There are number of places in this file where we convert
61// what is a 64-bit assembler value used for computation into a value in the
62// object file, which may truncate it. We should detect that truncation where
63// invalid and report errors back.
64
65/* *** */
66
67MCAsmLayout::MCAsmLayout(MCAssembler &Asm)
68  : Assembler(Asm), LastValidFragment()
69 {
70  // Compute the section layout order. Virtual sections must go last.
71  for (MCAssembler::iterator it = Asm.begin(), ie = Asm.end(); it != ie; ++it)
72    if (!it->getSection().isVirtualSection())
73      SectionOrder.push_back(&*it);
74  for (MCAssembler::iterator it = Asm.begin(), ie = Asm.end(); it != ie; ++it)
75    if (it->getSection().isVirtualSection())
76      SectionOrder.push_back(&*it);
77}
78
79bool MCAsmLayout::isFragmentValid(const MCFragment *F) const {
80  const MCSectionData &SD = *F->getParent();
81  const MCFragment *LastValid = LastValidFragment.lookup(&SD);
82  if (!LastValid)
83    return false;
84  assert(LastValid->getParent() == F->getParent());
85  return F->getLayoutOrder() <= LastValid->getLayoutOrder();
86}
87
88void MCAsmLayout::invalidateFragmentsFrom(MCFragment *F) {
89  // If this fragment wasn't already valid, we don't need to do anything.
90  if (!isFragmentValid(F))
91    return;
92
93  // Otherwise, reset the last valid fragment to the previous fragment
94  // (if this is the first fragment, it will be NULL).
95  const MCSectionData &SD = *F->getParent();
96  LastValidFragment[&SD] = F->getPrevNode();
97}
98
99void MCAsmLayout::ensureValid(const MCFragment *F) const {
100  MCSectionData &SD = *F->getParent();
101
102  MCFragment *Cur = LastValidFragment[&SD];
103  if (!Cur)
104    Cur = &*SD.begin();
105  else
106    Cur = Cur->getNextNode();
107
108  // Advance the layout position until the fragment is valid.
109  while (!isFragmentValid(F)) {
110    assert(Cur && "Layout bookkeeping error");
111    const_cast<MCAsmLayout*>(this)->layoutFragment(Cur);
112    Cur = Cur->getNextNode();
113  }
114}
115
116uint64_t MCAsmLayout::getFragmentOffset(const MCFragment *F) const {
117  ensureValid(F);
118  assert(F->Offset != ~UINT64_C(0) && "Address not set!");
119  return F->Offset;
120}
121
122uint64_t MCAsmLayout::getSymbolOffset(const MCSymbolData *SD) const {
123  const MCSymbol &S = SD->getSymbol();
124
125  // If this is a variable, then recursively evaluate now.
126  if (S.isVariable()) {
127    MCValue Target;
128    if (!S.getVariableValue()->EvaluateAsRelocatable(Target, this))
129      report_fatal_error("unable to evaluate offset for variable '" +
130                         S.getName() + "'");
131
132    // Verify that any used symbols are defined.
133    if (Target.getSymA() && Target.getSymA()->getSymbol().isUndefined())
134      report_fatal_error("unable to evaluate offset to undefined symbol '" +
135                         Target.getSymA()->getSymbol().getName() + "'");
136    if (Target.getSymB() && Target.getSymB()->getSymbol().isUndefined())
137      report_fatal_error("unable to evaluate offset to undefined symbol '" +
138                         Target.getSymB()->getSymbol().getName() + "'");
139
140    uint64_t Offset = Target.getConstant();
141    if (Target.getSymA())
142      Offset += getSymbolOffset(&Assembler.getSymbolData(
143                                  Target.getSymA()->getSymbol()));
144    if (Target.getSymB())
145      Offset -= getSymbolOffset(&Assembler.getSymbolData(
146                                  Target.getSymB()->getSymbol()));
147    return Offset;
148  }
149
150  assert(SD->getFragment() && "Invalid getOffset() on undefined symbol!");
151  return getFragmentOffset(SD->getFragment()) + SD->getOffset();
152}
153
154uint64_t MCAsmLayout::getSectionAddressSize(const MCSectionData *SD) const {
155  // The size is the last fragment's end offset.
156  const MCFragment &F = SD->getFragmentList().back();
157  return getFragmentOffset(&F) + getAssembler().computeFragmentSize(*this, F);
158}
159
160uint64_t MCAsmLayout::getSectionFileSize(const MCSectionData *SD) const {
161  // Virtual sections have no file size.
162  if (SD->getSection().isVirtualSection())
163    return 0;
164
165  // Otherwise, the file size is the same as the address space size.
166  return getSectionAddressSize(SD);
167}
168
169uint64_t MCAsmLayout::computeBundlePadding(const MCFragment *F,
170                                           uint64_t FOffset, uint64_t FSize) {
171  uint64_t BundleSize = Assembler.getBundleAlignSize();
172  assert(BundleSize > 0 &&
173         "computeBundlePadding should only be called if bundling is enabled");
174  uint64_t BundleMask = BundleSize - 1;
175  uint64_t OffsetInBundle = FOffset & BundleMask;
176  uint64_t EndOfFragment = OffsetInBundle + FSize;
177
178  // There are two kinds of bundling restrictions:
179  //
180  // 1) For alignToBundleEnd(), add padding to ensure that the fragment will
181  //    *end* on a bundle boundary.
182  // 2) Otherwise, check if the fragment would cross a bundle boundary. If it
183  //    would, add padding until the end of the bundle so that the fragment
184  //    will start in a new one.
185  if (F->alignToBundleEnd()) {
186    // Three possibilities here:
187    //
188    // A) The fragment just happens to end at a bundle boundary, so we're good.
189    // B) The fragment ends before the current bundle boundary: pad it just
190    //    enough to reach the boundary.
191    // C) The fragment ends after the current bundle boundary: pad it until it
192    //    reaches the end of the next bundle boundary.
193    //
194    // Note: this code could be made shorter with some modulo trickery, but it's
195    // intentionally kept in its more explicit form for simplicity.
196    if (EndOfFragment == BundleSize)
197      return 0;
198    else if (EndOfFragment < BundleSize)
199      return BundleSize - EndOfFragment;
200    else { // EndOfFragment > BundleSize
201      return 2 * BundleSize - EndOfFragment;
202    }
203  } else if (EndOfFragment > BundleSize)
204    return BundleSize - OffsetInBundle;
205  else
206    return 0;
207}
208
209/* *** */
210
211MCFragment::MCFragment() : Kind(FragmentType(~0)) {
212}
213
214MCFragment::~MCFragment() {
215}
216
217MCFragment::MCFragment(FragmentType _Kind, MCSectionData *_Parent)
218  : Kind(_Kind), Parent(_Parent), Atom(0), Offset(~UINT64_C(0))
219{
220  if (Parent)
221    Parent->getFragmentList().push_back(this);
222}
223
224/* *** */
225
226MCEncodedFragment::~MCEncodedFragment() {
227}
228
229/* *** */
230
231MCEncodedFragmentWithFixups::~MCEncodedFragmentWithFixups() {
232}
233
234/* *** */
235
236const SmallVectorImpl<char> &MCCompressedFragment::getCompressedContents() const {
237  assert(getParent()->size() == 1 &&
238         "Only compress sections containing a single fragment");
239  if (CompressedContents.empty()) {
240    std::unique_ptr<MemoryBuffer> CompressedSection;
241    zlib::Status Success =
242        zlib::compress(StringRef(getContents().data(), getContents().size()),
243                       CompressedSection);
244    (void)Success;
245    assert(Success == zlib::StatusOK);
246    CompressedContents.push_back('Z');
247    CompressedContents.push_back('L');
248    CompressedContents.push_back('I');
249    CompressedContents.push_back('B');
250    uint64_t Size = getContents().size();
251    if (sys::IsLittleEndianHost)
252      Size = sys::SwapByteOrder(Size);
253    CompressedContents.append(reinterpret_cast<char *>(&Size),
254                              reinterpret_cast<char *>(&Size + 1));
255    CompressedContents.append(CompressedSection->getBuffer().begin(),
256                              CompressedSection->getBuffer().end());
257  }
258  return CompressedContents;
259}
260
261SmallVectorImpl<char> &MCCompressedFragment::getContents() {
262  assert(CompressedContents.empty() &&
263         "Fragment contents should not be altered after compression");
264  return MCDataFragment::getContents();
265}
266
267/* *** */
268
269MCSectionData::MCSectionData() : Section(0) {}
270
271MCSectionData::MCSectionData(const MCSection &_Section, MCAssembler *A)
272  : Section(&_Section),
273    Ordinal(~UINT32_C(0)),
274    Alignment(1),
275    BundleLockState(NotBundleLocked), BundleGroupBeforeFirstInst(false),
276    HasInstructions(false)
277{
278  if (A)
279    A->getSectionList().push_back(this);
280}
281
282MCSectionData::iterator
283MCSectionData::getSubsectionInsertionPoint(unsigned Subsection) {
284  if (Subsection == 0 && SubsectionFragmentMap.empty())
285    return end();
286
287  SmallVectorImpl<std::pair<unsigned, MCFragment *> >::iterator MI =
288    std::lower_bound(SubsectionFragmentMap.begin(), SubsectionFragmentMap.end(),
289                     std::make_pair(Subsection, (MCFragment *)0));
290  bool ExactMatch = false;
291  if (MI != SubsectionFragmentMap.end()) {
292    ExactMatch = MI->first == Subsection;
293    if (ExactMatch)
294      ++MI;
295  }
296  iterator IP;
297  if (MI == SubsectionFragmentMap.end())
298    IP = end();
299  else
300    IP = MI->second;
301  if (!ExactMatch && Subsection != 0) {
302    // The GNU as documentation claims that subsections have an alignment of 4,
303    // although this appears not to be the case.
304    MCFragment *F = new MCDataFragment();
305    SubsectionFragmentMap.insert(MI, std::make_pair(Subsection, F));
306    getFragmentList().insert(IP, F);
307    F->setParent(this);
308  }
309  return IP;
310}
311
312/* *** */
313
314MCSymbolData::MCSymbolData() : Symbol(0) {}
315
316MCSymbolData::MCSymbolData(const MCSymbol &_Symbol, MCFragment *_Fragment,
317                           uint64_t _Offset, MCAssembler *A)
318  : Symbol(&_Symbol), Fragment(_Fragment), Offset(_Offset),
319    IsExternal(false), IsPrivateExtern(false),
320    CommonSize(0), SymbolSize(0), CommonAlign(0),
321    Flags(0), Index(0)
322{
323  if (A)
324    A->getSymbolList().push_back(this);
325}
326
327/* *** */
328
329MCAssembler::MCAssembler(MCContext &Context_, MCAsmBackend &Backend_,
330                         MCCodeEmitter &Emitter_, MCObjectWriter &Writer_,
331                         raw_ostream &OS_)
332  : Context(Context_), Backend(Backend_), Emitter(Emitter_), Writer(Writer_),
333    OS(OS_), BundleAlignSize(0), RelaxAll(false), NoExecStack(false),
334    SubsectionsViaSymbols(false), ELFHeaderEFlags(0) {
335  VersionMinInfo.Major = 0; // Major version == 0 for "none specified"
336}
337
338MCAssembler::~MCAssembler() {
339}
340
341void MCAssembler::reset() {
342  Sections.clear();
343  Symbols.clear();
344  SectionMap.clear();
345  SymbolMap.clear();
346  IndirectSymbols.clear();
347  DataRegions.clear();
348  ThumbFuncs.clear();
349  RelaxAll = false;
350  NoExecStack = false;
351  SubsectionsViaSymbols = false;
352  ELFHeaderEFlags = 0;
353
354  // reset objects owned by us
355  getBackend().reset();
356  getEmitter().reset();
357  getWriter().reset();
358  getLOHContainer().reset();
359}
360
361bool MCAssembler::isSymbolLinkerVisible(const MCSymbol &Symbol) const {
362  // Non-temporary labels should always be visible to the linker.
363  if (!Symbol.isTemporary())
364    return true;
365
366  // Absolute temporary labels are never visible.
367  if (!Symbol.isInSection())
368    return false;
369
370  // Otherwise, check if the section requires symbols even for temporary labels.
371  return getBackend().doesSectionRequireSymbols(Symbol.getSection());
372}
373
374const MCSymbolData *MCAssembler::getAtom(const MCSymbolData *SD) const {
375  // Linker visible symbols define atoms.
376  if (isSymbolLinkerVisible(SD->getSymbol()))
377    return SD;
378
379  // Absolute and undefined symbols have no defining atom.
380  if (!SD->getFragment())
381    return 0;
382
383  // Non-linker visible symbols in sections which can't be atomized have no
384  // defining atom.
385  if (!getBackend().isSectionAtomizable(
386        SD->getFragment()->getParent()->getSection()))
387    return 0;
388
389  // Otherwise, return the atom for the containing fragment.
390  return SD->getFragment()->getAtom();
391}
392
393bool MCAssembler::evaluateFixup(const MCAsmLayout &Layout,
394                                const MCFixup &Fixup, const MCFragment *DF,
395                                MCValue &Target, uint64_t &Value) const {
396  ++stats::evaluateFixup;
397
398  if (!Fixup.getValue()->EvaluateAsRelocatable(Target, &Layout))
399    getContext().FatalError(Fixup.getLoc(), "expected relocatable expression");
400
401  bool IsPCRel = Backend.getFixupKindInfo(
402    Fixup.getKind()).Flags & MCFixupKindInfo::FKF_IsPCRel;
403
404  bool IsResolved;
405  if (IsPCRel) {
406    if (Target.getSymB()) {
407      IsResolved = false;
408    } else if (!Target.getSymA()) {
409      IsResolved = false;
410    } else {
411      const MCSymbolRefExpr *A = Target.getSymA();
412      const MCSymbol &SA = A->getSymbol();
413      if (A->getKind() != MCSymbolRefExpr::VK_None ||
414          SA.AliasedSymbol().isUndefined()) {
415        IsResolved = false;
416      } else {
417        const MCSymbolData &DataA = getSymbolData(SA);
418        IsResolved =
419          getWriter().IsSymbolRefDifferenceFullyResolvedImpl(*this, DataA,
420                                                             *DF, false, true);
421      }
422    }
423  } else {
424    IsResolved = Target.isAbsolute();
425  }
426
427  Value = Target.getConstant();
428
429  if (const MCSymbolRefExpr *A = Target.getSymA()) {
430    const MCSymbol &Sym = A->getSymbol().AliasedSymbol();
431    if (Sym.isDefined())
432      Value += Layout.getSymbolOffset(&getSymbolData(Sym));
433  }
434  if (const MCSymbolRefExpr *B = Target.getSymB()) {
435    const MCSymbol &Sym = B->getSymbol().AliasedSymbol();
436    if (Sym.isDefined())
437      Value -= Layout.getSymbolOffset(&getSymbolData(Sym));
438  }
439
440
441  bool ShouldAlignPC = Backend.getFixupKindInfo(Fixup.getKind()).Flags &
442                         MCFixupKindInfo::FKF_IsAlignedDownTo32Bits;
443  assert((ShouldAlignPC ? IsPCRel : true) &&
444    "FKF_IsAlignedDownTo32Bits is only allowed on PC-relative fixups!");
445
446  if (IsPCRel) {
447    uint32_t Offset = Layout.getFragmentOffset(DF) + Fixup.getOffset();
448
449    // A number of ARM fixups in Thumb mode require that the effective PC
450    // address be determined as the 32-bit aligned version of the actual offset.
451    if (ShouldAlignPC) Offset &= ~0x3;
452    Value -= Offset;
453  }
454
455  // Let the backend adjust the fixup value if necessary, including whether
456  // we need a relocation.
457  Backend.processFixupValue(*this, Layout, Fixup, DF, Target, Value,
458                            IsResolved);
459
460  return IsResolved;
461}
462
463uint64_t MCAssembler::computeFragmentSize(const MCAsmLayout &Layout,
464                                          const MCFragment &F) const {
465  switch (F.getKind()) {
466  case MCFragment::FT_Data:
467  case MCFragment::FT_Relaxable:
468  case MCFragment::FT_CompactEncodedInst:
469    return cast<MCEncodedFragment>(F).getContents().size();
470  case MCFragment::FT_Compressed:
471    return cast<MCCompressedFragment>(F).getCompressedContents().size();
472  case MCFragment::FT_Fill:
473    return cast<MCFillFragment>(F).getSize();
474
475  case MCFragment::FT_LEB:
476    return cast<MCLEBFragment>(F).getContents().size();
477
478  case MCFragment::FT_Align: {
479    const MCAlignFragment &AF = cast<MCAlignFragment>(F);
480    unsigned Offset = Layout.getFragmentOffset(&AF);
481    unsigned Size = OffsetToAlignment(Offset, AF.getAlignment());
482    // If we are padding with nops, force the padding to be larger than the
483    // minimum nop size.
484    if (Size > 0 && AF.hasEmitNops()) {
485      while (Size % getBackend().getMinimumNopSize())
486        Size += AF.getAlignment();
487    }
488    if (Size > AF.getMaxBytesToEmit())
489      return 0;
490    return Size;
491  }
492
493  case MCFragment::FT_Org: {
494    const MCOrgFragment &OF = cast<MCOrgFragment>(F);
495    int64_t TargetLocation;
496    if (!OF.getOffset().EvaluateAsAbsolute(TargetLocation, Layout))
497      report_fatal_error("expected assembly-time absolute expression");
498
499    // FIXME: We need a way to communicate this error.
500    uint64_t FragmentOffset = Layout.getFragmentOffset(&OF);
501    int64_t Size = TargetLocation - FragmentOffset;
502    if (Size < 0 || Size >= 0x40000000)
503      report_fatal_error("invalid .org offset '" + Twine(TargetLocation) +
504                         "' (at offset '" + Twine(FragmentOffset) + "')");
505    return Size;
506  }
507
508  case MCFragment::FT_Dwarf:
509    return cast<MCDwarfLineAddrFragment>(F).getContents().size();
510  case MCFragment::FT_DwarfFrame:
511    return cast<MCDwarfCallFrameFragment>(F).getContents().size();
512  }
513
514  llvm_unreachable("invalid fragment kind");
515}
516
517void MCAsmLayout::layoutFragment(MCFragment *F) {
518  MCFragment *Prev = F->getPrevNode();
519
520  // We should never try to recompute something which is valid.
521  assert(!isFragmentValid(F) && "Attempt to recompute a valid fragment!");
522  // We should never try to compute the fragment layout if its predecessor
523  // isn't valid.
524  assert((!Prev || isFragmentValid(Prev)) &&
525         "Attempt to compute fragment before its predecessor!");
526
527  ++stats::FragmentLayouts;
528
529  // Compute fragment offset and size.
530  if (Prev)
531    F->Offset = Prev->Offset + getAssembler().computeFragmentSize(*this, *Prev);
532  else
533    F->Offset = 0;
534  LastValidFragment[F->getParent()] = F;
535
536  // If bundling is enabled and this fragment has instructions in it, it has to
537  // obey the bundling restrictions. With padding, we'll have:
538  //
539  //
540  //        BundlePadding
541  //             |||
542  // -------------------------------------
543  //   Prev  |##########|       F        |
544  // -------------------------------------
545  //                    ^
546  //                    |
547  //                    F->Offset
548  //
549  // The fragment's offset will point to after the padding, and its computed
550  // size won't include the padding.
551  //
552  if (Assembler.isBundlingEnabled() && F->hasInstructions()) {
553    assert(isa<MCEncodedFragment>(F) &&
554           "Only MCEncodedFragment implementations have instructions");
555    uint64_t FSize = Assembler.computeFragmentSize(*this, *F);
556
557    if (FSize > Assembler.getBundleAlignSize())
558      report_fatal_error("Fragment can't be larger than a bundle size");
559
560    uint64_t RequiredBundlePadding = computeBundlePadding(F, F->Offset, FSize);
561    if (RequiredBundlePadding > UINT8_MAX)
562      report_fatal_error("Padding cannot exceed 255 bytes");
563    F->setBundlePadding(static_cast<uint8_t>(RequiredBundlePadding));
564    F->Offset += RequiredBundlePadding;
565  }
566}
567
568/// \brief Write the contents of a fragment to the given object writer. Expects
569///        a MCEncodedFragment.
570static void writeFragmentContents(const MCFragment &F, MCObjectWriter *OW) {
571  const MCEncodedFragment &EF = cast<MCEncodedFragment>(F);
572  OW->WriteBytes(EF.getContents());
573}
574
575/// \brief Write the fragment \p F to the output file.
576static void writeFragment(const MCAssembler &Asm, const MCAsmLayout &Layout,
577                          const MCFragment &F) {
578  MCObjectWriter *OW = &Asm.getWriter();
579
580  // FIXME: Embed in fragments instead?
581  uint64_t FragmentSize = Asm.computeFragmentSize(Layout, F);
582
583  // Should NOP padding be written out before this fragment?
584  unsigned BundlePadding = F.getBundlePadding();
585  if (BundlePadding > 0) {
586    assert(Asm.isBundlingEnabled() &&
587           "Writing bundle padding with disabled bundling");
588    assert(F.hasInstructions() &&
589           "Writing bundle padding for a fragment without instructions");
590
591    unsigned TotalLength = BundlePadding + static_cast<unsigned>(FragmentSize);
592    if (F.alignToBundleEnd() && TotalLength > Asm.getBundleAlignSize()) {
593      // If the padding itself crosses a bundle boundary, it must be emitted
594      // in 2 pieces, since even nop instructions must not cross boundaries.
595      //             v--------------v   <- BundleAlignSize
596      //        v---------v             <- BundlePadding
597      // ----------------------------
598      // | Prev |####|####|    F    |
599      // ----------------------------
600      //        ^-------------------^   <- TotalLength
601      unsigned DistanceToBoundary = TotalLength - Asm.getBundleAlignSize();
602      if (!Asm.getBackend().writeNopData(DistanceToBoundary, OW))
603          report_fatal_error("unable to write NOP sequence of " +
604                             Twine(DistanceToBoundary) + " bytes");
605      BundlePadding -= DistanceToBoundary;
606    }
607    if (!Asm.getBackend().writeNopData(BundlePadding, OW))
608      report_fatal_error("unable to write NOP sequence of " +
609                         Twine(BundlePadding) + " bytes");
610  }
611
612  // This variable (and its dummy usage) is to participate in the assert at
613  // the end of the function.
614  uint64_t Start = OW->getStream().tell();
615  (void) Start;
616
617  ++stats::EmittedFragments;
618
619  switch (F.getKind()) {
620  case MCFragment::FT_Align: {
621    ++stats::EmittedAlignFragments;
622    const MCAlignFragment &AF = cast<MCAlignFragment>(F);
623    assert(AF.getValueSize() && "Invalid virtual align in concrete fragment!");
624
625    uint64_t Count = FragmentSize / AF.getValueSize();
626
627    // FIXME: This error shouldn't actually occur (the front end should emit
628    // multiple .align directives to enforce the semantics it wants), but is
629    // severe enough that we want to report it. How to handle this?
630    if (Count * AF.getValueSize() != FragmentSize)
631      report_fatal_error("undefined .align directive, value size '" +
632                        Twine(AF.getValueSize()) +
633                        "' is not a divisor of padding size '" +
634                        Twine(FragmentSize) + "'");
635
636    // See if we are aligning with nops, and if so do that first to try to fill
637    // the Count bytes.  Then if that did not fill any bytes or there are any
638    // bytes left to fill use the Value and ValueSize to fill the rest.
639    // If we are aligning with nops, ask that target to emit the right data.
640    if (AF.hasEmitNops()) {
641      if (!Asm.getBackend().writeNopData(Count, OW))
642        report_fatal_error("unable to write nop sequence of " +
643                          Twine(Count) + " bytes");
644      break;
645    }
646
647    // Otherwise, write out in multiples of the value size.
648    for (uint64_t i = 0; i != Count; ++i) {
649      switch (AF.getValueSize()) {
650      default: llvm_unreachable("Invalid size!");
651      case 1: OW->Write8 (uint8_t (AF.getValue())); break;
652      case 2: OW->Write16(uint16_t(AF.getValue())); break;
653      case 4: OW->Write32(uint32_t(AF.getValue())); break;
654      case 8: OW->Write64(uint64_t(AF.getValue())); break;
655      }
656    }
657    break;
658  }
659
660  case MCFragment::FT_Compressed:
661    ++stats::EmittedDataFragments;
662    OW->WriteBytes(cast<MCCompressedFragment>(F).getCompressedContents());
663    break;
664
665  case MCFragment::FT_Data:
666    ++stats::EmittedDataFragments;
667    writeFragmentContents(F, OW);
668    break;
669
670  case MCFragment::FT_Relaxable:
671    ++stats::EmittedRelaxableFragments;
672    writeFragmentContents(F, OW);
673    break;
674
675  case MCFragment::FT_CompactEncodedInst:
676    ++stats::EmittedCompactEncodedInstFragments;
677    writeFragmentContents(F, OW);
678    break;
679
680  case MCFragment::FT_Fill: {
681    ++stats::EmittedFillFragments;
682    const MCFillFragment &FF = cast<MCFillFragment>(F);
683
684    assert(FF.getValueSize() && "Invalid virtual align in concrete fragment!");
685
686    for (uint64_t i = 0, e = FF.getSize() / FF.getValueSize(); i != e; ++i) {
687      switch (FF.getValueSize()) {
688      default: llvm_unreachable("Invalid size!");
689      case 1: OW->Write8 (uint8_t (FF.getValue())); break;
690      case 2: OW->Write16(uint16_t(FF.getValue())); break;
691      case 4: OW->Write32(uint32_t(FF.getValue())); break;
692      case 8: OW->Write64(uint64_t(FF.getValue())); break;
693      }
694    }
695    break;
696  }
697
698  case MCFragment::FT_LEB: {
699    const MCLEBFragment &LF = cast<MCLEBFragment>(F);
700    OW->WriteBytes(LF.getContents().str());
701    break;
702  }
703
704  case MCFragment::FT_Org: {
705    ++stats::EmittedOrgFragments;
706    const MCOrgFragment &OF = cast<MCOrgFragment>(F);
707
708    for (uint64_t i = 0, e = FragmentSize; i != e; ++i)
709      OW->Write8(uint8_t(OF.getValue()));
710
711    break;
712  }
713
714  case MCFragment::FT_Dwarf: {
715    const MCDwarfLineAddrFragment &OF = cast<MCDwarfLineAddrFragment>(F);
716    OW->WriteBytes(OF.getContents().str());
717    break;
718  }
719  case MCFragment::FT_DwarfFrame: {
720    const MCDwarfCallFrameFragment &CF = cast<MCDwarfCallFrameFragment>(F);
721    OW->WriteBytes(CF.getContents().str());
722    break;
723  }
724  }
725
726  assert(OW->getStream().tell() - Start == FragmentSize &&
727         "The stream should advance by fragment size");
728}
729
730void MCAssembler::writeSectionData(const MCSectionData *SD,
731                                   const MCAsmLayout &Layout) const {
732  // Ignore virtual sections.
733  if (SD->getSection().isVirtualSection()) {
734    assert(Layout.getSectionFileSize(SD) == 0 && "Invalid size for section!");
735
736    // Check that contents are only things legal inside a virtual section.
737    for (MCSectionData::const_iterator it = SD->begin(),
738           ie = SD->end(); it != ie; ++it) {
739      switch (it->getKind()) {
740      default: llvm_unreachable("Invalid fragment in virtual section!");
741      case MCFragment::FT_Compressed:
742      case MCFragment::FT_Data: {
743        // Check that we aren't trying to write a non-zero contents (or fixups)
744        // into a virtual section. This is to support clients which use standard
745        // directives to fill the contents of virtual sections.
746        const MCDataFragment &DF = cast<MCDataFragment>(*it);
747        assert(DF.fixup_begin() == DF.fixup_end() &&
748               "Cannot have fixups in virtual section!");
749        for (unsigned i = 0, e = DF.getContents().size(); i != e; ++i)
750          assert(DF.getContents()[i] == 0 &&
751                 "Invalid data value for virtual section!");
752        break;
753      }
754      case MCFragment::FT_Align:
755        // Check that we aren't trying to write a non-zero value into a virtual
756        // section.
757        assert((cast<MCAlignFragment>(it)->getValueSize() == 0 ||
758                cast<MCAlignFragment>(it)->getValue() == 0) &&
759               "Invalid align in virtual section!");
760        break;
761      case MCFragment::FT_Fill:
762        assert((cast<MCFillFragment>(it)->getValueSize() == 0 ||
763                cast<MCFillFragment>(it)->getValue() == 0) &&
764               "Invalid fill in virtual section!");
765        break;
766      }
767    }
768
769    return;
770  }
771
772  uint64_t Start = getWriter().getStream().tell();
773  (void)Start;
774
775  for (MCSectionData::const_iterator it = SD->begin(), ie = SD->end();
776       it != ie; ++it)
777    writeFragment(*this, Layout, *it);
778
779  assert(getWriter().getStream().tell() - Start ==
780         Layout.getSectionAddressSize(SD));
781}
782
783std::pair<uint64_t, bool> MCAssembler::handleFixup(const MCAsmLayout &Layout,
784                                                   MCFragment &F,
785                                                   const MCFixup &Fixup) {
786  // Evaluate the fixup.
787  MCValue Target;
788  uint64_t FixedValue;
789  bool IsPCRel = Backend.getFixupKindInfo(Fixup.getKind()).Flags &
790                 MCFixupKindInfo::FKF_IsPCRel;
791  if (!evaluateFixup(Layout, Fixup, &F, Target, FixedValue)) {
792    // The fixup was unresolved, we need a relocation. Inform the object
793    // writer of the relocation, and give it an opportunity to adjust the
794    // fixup value if need be.
795    getWriter().RecordRelocation(*this, Layout, &F, Fixup, Target, IsPCRel,
796                                 FixedValue);
797  }
798  return std::make_pair(FixedValue, IsPCRel);
799}
800
801void MCAssembler::Finish() {
802  DEBUG_WITH_TYPE("mc-dump", {
803      llvm::errs() << "assembler backend - pre-layout\n--\n";
804      dump(); });
805
806  // Create the layout object.
807  MCAsmLayout Layout(*this);
808
809  // Create dummy fragments and assign section ordinals.
810  unsigned SectionIndex = 0;
811  for (MCAssembler::iterator it = begin(), ie = end(); it != ie; ++it) {
812    // Create dummy fragments to eliminate any empty sections, this simplifies
813    // layout.
814    if (it->getFragmentList().empty())
815      new MCDataFragment(it);
816
817    it->setOrdinal(SectionIndex++);
818  }
819
820  // Assign layout order indices to sections and fragments.
821  for (unsigned i = 0, e = Layout.getSectionOrder().size(); i != e; ++i) {
822    MCSectionData *SD = Layout.getSectionOrder()[i];
823    SD->setLayoutOrder(i);
824
825    unsigned FragmentIndex = 0;
826    for (MCSectionData::iterator iFrag = SD->begin(), iFragEnd = SD->end();
827         iFrag != iFragEnd; ++iFrag)
828      iFrag->setLayoutOrder(FragmentIndex++);
829  }
830
831  // Layout until everything fits.
832  while (layoutOnce(Layout))
833    continue;
834
835  DEBUG_WITH_TYPE("mc-dump", {
836      llvm::errs() << "assembler backend - post-relaxation\n--\n";
837      dump(); });
838
839  // Finalize the layout, including fragment lowering.
840  finishLayout(Layout);
841
842  DEBUG_WITH_TYPE("mc-dump", {
843      llvm::errs() << "assembler backend - final-layout\n--\n";
844      dump(); });
845
846  uint64_t StartOffset = OS.tell();
847
848  // Allow the object writer a chance to perform post-layout binding (for
849  // example, to set the index fields in the symbol data).
850  getWriter().ExecutePostLayoutBinding(*this, Layout);
851
852  // Evaluate and apply the fixups, generating relocation entries as necessary.
853  for (MCAssembler::iterator it = begin(), ie = end(); it != ie; ++it) {
854    for (MCSectionData::iterator it2 = it->begin(),
855           ie2 = it->end(); it2 != ie2; ++it2) {
856      MCEncodedFragmentWithFixups *F =
857        dyn_cast<MCEncodedFragmentWithFixups>(it2);
858      if (F) {
859        for (MCEncodedFragmentWithFixups::fixup_iterator it3 = F->fixup_begin(),
860             ie3 = F->fixup_end(); it3 != ie3; ++it3) {
861          MCFixup &Fixup = *it3;
862          uint64_t FixedValue;
863          bool IsPCRel;
864          std::tie(FixedValue, IsPCRel) = handleFixup(Layout, *F, Fixup);
865          getBackend().applyFixup(Fixup, F->getContents().data(),
866                                  F->getContents().size(), FixedValue, IsPCRel);
867        }
868      }
869    }
870  }
871
872  // Write the object file.
873  getWriter().WriteObject(*this, Layout);
874
875  stats::ObjectBytes += OS.tell() - StartOffset;
876}
877
878bool MCAssembler::fixupNeedsRelaxation(const MCFixup &Fixup,
879                                       const MCRelaxableFragment *DF,
880                                       const MCAsmLayout &Layout) const {
881  // If we cannot resolve the fixup value, it requires relaxation.
882  MCValue Target;
883  uint64_t Value;
884  if (!evaluateFixup(Layout, Fixup, DF, Target, Value))
885    return true;
886
887  return getBackend().fixupNeedsRelaxation(Fixup, Value, DF, Layout);
888}
889
890bool MCAssembler::fragmentNeedsRelaxation(const MCRelaxableFragment *F,
891                                          const MCAsmLayout &Layout) const {
892  // If this inst doesn't ever need relaxation, ignore it. This occurs when we
893  // are intentionally pushing out inst fragments, or because we relaxed a
894  // previous instruction to one that doesn't need relaxation.
895  if (!getBackend().mayNeedRelaxation(F->getInst()))
896    return false;
897
898  for (MCRelaxableFragment::const_fixup_iterator it = F->fixup_begin(),
899       ie = F->fixup_end(); it != ie; ++it)
900    if (fixupNeedsRelaxation(*it, F, Layout))
901      return true;
902
903  return false;
904}
905
906bool MCAssembler::relaxInstruction(MCAsmLayout &Layout,
907                                   MCRelaxableFragment &F) {
908  if (!fragmentNeedsRelaxation(&F, Layout))
909    return false;
910
911  ++stats::RelaxedInstructions;
912
913  // FIXME-PERF: We could immediately lower out instructions if we can tell
914  // they are fully resolved, to avoid retesting on later passes.
915
916  // Relax the fragment.
917
918  MCInst Relaxed;
919  getBackend().relaxInstruction(F.getInst(), Relaxed);
920
921  // Encode the new instruction.
922  //
923  // FIXME-PERF: If it matters, we could let the target do this. It can
924  // probably do so more efficiently in many cases.
925  SmallVector<MCFixup, 4> Fixups;
926  SmallString<256> Code;
927  raw_svector_ostream VecOS(Code);
928  getEmitter().EncodeInstruction(Relaxed, VecOS, Fixups, F.getSubtargetInfo());
929  VecOS.flush();
930
931  // Update the fragment.
932  F.setInst(Relaxed);
933  F.getContents() = Code;
934  F.getFixups() = Fixups;
935
936  return true;
937}
938
939bool MCAssembler::relaxLEB(MCAsmLayout &Layout, MCLEBFragment &LF) {
940  int64_t Value = 0;
941  uint64_t OldSize = LF.getContents().size();
942  bool IsAbs = LF.getValue().EvaluateAsAbsolute(Value, Layout);
943  (void)IsAbs;
944  assert(IsAbs);
945  SmallString<8> &Data = LF.getContents();
946  Data.clear();
947  raw_svector_ostream OSE(Data);
948  if (LF.isSigned())
949    encodeSLEB128(Value, OSE);
950  else
951    encodeULEB128(Value, OSE);
952  OSE.flush();
953  return OldSize != LF.getContents().size();
954}
955
956bool MCAssembler::relaxDwarfLineAddr(MCAsmLayout &Layout,
957                                     MCDwarfLineAddrFragment &DF) {
958  MCContext &Context = Layout.getAssembler().getContext();
959  int64_t AddrDelta = 0;
960  uint64_t OldSize = DF.getContents().size();
961  bool IsAbs = DF.getAddrDelta().EvaluateAsAbsolute(AddrDelta, Layout);
962  (void)IsAbs;
963  assert(IsAbs);
964  int64_t LineDelta;
965  LineDelta = DF.getLineDelta();
966  SmallString<8> &Data = DF.getContents();
967  Data.clear();
968  raw_svector_ostream OSE(Data);
969  MCDwarfLineAddr::Encode(Context, LineDelta, AddrDelta, OSE);
970  OSE.flush();
971  return OldSize != Data.size();
972}
973
974bool MCAssembler::relaxDwarfCallFrameFragment(MCAsmLayout &Layout,
975                                              MCDwarfCallFrameFragment &DF) {
976  MCContext &Context = Layout.getAssembler().getContext();
977  int64_t AddrDelta = 0;
978  uint64_t OldSize = DF.getContents().size();
979  bool IsAbs = DF.getAddrDelta().EvaluateAsAbsolute(AddrDelta, Layout);
980  (void)IsAbs;
981  assert(IsAbs);
982  SmallString<8> &Data = DF.getContents();
983  Data.clear();
984  raw_svector_ostream OSE(Data);
985  MCDwarfFrameEmitter::EncodeAdvanceLoc(Context, AddrDelta, OSE);
986  OSE.flush();
987  return OldSize != Data.size();
988}
989
990bool MCAssembler::layoutSectionOnce(MCAsmLayout &Layout, MCSectionData &SD) {
991  // Holds the first fragment which needed relaxing during this layout. It will
992  // remain NULL if none were relaxed.
993  // When a fragment is relaxed, all the fragments following it should get
994  // invalidated because their offset is going to change.
995  MCFragment *FirstRelaxedFragment = NULL;
996
997  // Attempt to relax all the fragments in the section.
998  for (MCSectionData::iterator I = SD.begin(), IE = SD.end(); I != IE; ++I) {
999    // Check if this is a fragment that needs relaxation.
1000    bool RelaxedFrag = false;
1001    switch(I->getKind()) {
1002    default:
1003      break;
1004    case MCFragment::FT_Relaxable:
1005      assert(!getRelaxAll() &&
1006             "Did not expect a MCRelaxableFragment in RelaxAll mode");
1007      RelaxedFrag = relaxInstruction(Layout, *cast<MCRelaxableFragment>(I));
1008      break;
1009    case MCFragment::FT_Dwarf:
1010      RelaxedFrag = relaxDwarfLineAddr(Layout,
1011                                       *cast<MCDwarfLineAddrFragment>(I));
1012      break;
1013    case MCFragment::FT_DwarfFrame:
1014      RelaxedFrag =
1015        relaxDwarfCallFrameFragment(Layout,
1016                                    *cast<MCDwarfCallFrameFragment>(I));
1017      break;
1018    case MCFragment::FT_LEB:
1019      RelaxedFrag = relaxLEB(Layout, *cast<MCLEBFragment>(I));
1020      break;
1021    }
1022    if (RelaxedFrag && !FirstRelaxedFragment)
1023      FirstRelaxedFragment = I;
1024  }
1025  if (FirstRelaxedFragment) {
1026    Layout.invalidateFragmentsFrom(FirstRelaxedFragment);
1027    return true;
1028  }
1029  return false;
1030}
1031
1032bool MCAssembler::layoutOnce(MCAsmLayout &Layout) {
1033  ++stats::RelaxationSteps;
1034
1035  bool WasRelaxed = false;
1036  for (iterator it = begin(), ie = end(); it != ie; ++it) {
1037    MCSectionData &SD = *it;
1038    while (layoutSectionOnce(Layout, SD))
1039      WasRelaxed = true;
1040  }
1041
1042  return WasRelaxed;
1043}
1044
1045void MCAssembler::finishLayout(MCAsmLayout &Layout) {
1046  // The layout is done. Mark every fragment as valid.
1047  for (unsigned int i = 0, n = Layout.getSectionOrder().size(); i != n; ++i) {
1048    Layout.getFragmentOffset(&*Layout.getSectionOrder()[i]->rbegin());
1049  }
1050}
1051
1052// Debugging methods
1053
1054namespace llvm {
1055
1056raw_ostream &operator<<(raw_ostream &OS, const MCFixup &AF) {
1057  OS << "<MCFixup" << " Offset:" << AF.getOffset()
1058     << " Value:" << *AF.getValue()
1059     << " Kind:" << AF.getKind() << ">";
1060  return OS;
1061}
1062
1063}
1064
1065#if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
1066void MCFragment::dump() {
1067  raw_ostream &OS = llvm::errs();
1068
1069  OS << "<";
1070  switch (getKind()) {
1071  case MCFragment::FT_Align: OS << "MCAlignFragment"; break;
1072  case MCFragment::FT_Data:  OS << "MCDataFragment"; break;
1073  case MCFragment::FT_Compressed:
1074    OS << "MCCompressedFragment"; break;
1075  case MCFragment::FT_CompactEncodedInst:
1076    OS << "MCCompactEncodedInstFragment"; break;
1077  case MCFragment::FT_Fill:  OS << "MCFillFragment"; break;
1078  case MCFragment::FT_Relaxable:  OS << "MCRelaxableFragment"; break;
1079  case MCFragment::FT_Org:   OS << "MCOrgFragment"; break;
1080  case MCFragment::FT_Dwarf: OS << "MCDwarfFragment"; break;
1081  case MCFragment::FT_DwarfFrame: OS << "MCDwarfCallFrameFragment"; break;
1082  case MCFragment::FT_LEB:   OS << "MCLEBFragment"; break;
1083  }
1084
1085  OS << "<MCFragment " << (void*) this << " LayoutOrder:" << LayoutOrder
1086     << " Offset:" << Offset
1087     << " HasInstructions:" << hasInstructions()
1088     << " BundlePadding:" << static_cast<unsigned>(getBundlePadding()) << ">";
1089
1090  switch (getKind()) {
1091  case MCFragment::FT_Align: {
1092    const MCAlignFragment *AF = cast<MCAlignFragment>(this);
1093    if (AF->hasEmitNops())
1094      OS << " (emit nops)";
1095    OS << "\n       ";
1096    OS << " Alignment:" << AF->getAlignment()
1097       << " Value:" << AF->getValue() << " ValueSize:" << AF->getValueSize()
1098       << " MaxBytesToEmit:" << AF->getMaxBytesToEmit() << ">";
1099    break;
1100  }
1101  case MCFragment::FT_Compressed:
1102  case MCFragment::FT_Data:  {
1103    const MCDataFragment *DF = cast<MCDataFragment>(this);
1104    OS << "\n       ";
1105    OS << " Contents:[";
1106    const SmallVectorImpl<char> &Contents = DF->getContents();
1107    for (unsigned i = 0, e = Contents.size(); i != e; ++i) {
1108      if (i) OS << ",";
1109      OS << hexdigit((Contents[i] >> 4) & 0xF) << hexdigit(Contents[i] & 0xF);
1110    }
1111    OS << "] (" << Contents.size() << " bytes)";
1112
1113    if (DF->fixup_begin() != DF->fixup_end()) {
1114      OS << ",\n       ";
1115      OS << " Fixups:[";
1116      for (MCDataFragment::const_fixup_iterator it = DF->fixup_begin(),
1117             ie = DF->fixup_end(); it != ie; ++it) {
1118        if (it != DF->fixup_begin()) OS << ",\n                ";
1119        OS << *it;
1120      }
1121      OS << "]";
1122    }
1123    break;
1124  }
1125  case MCFragment::FT_CompactEncodedInst: {
1126    const MCCompactEncodedInstFragment *CEIF =
1127      cast<MCCompactEncodedInstFragment>(this);
1128    OS << "\n       ";
1129    OS << " Contents:[";
1130    const SmallVectorImpl<char> &Contents = CEIF->getContents();
1131    for (unsigned i = 0, e = Contents.size(); i != e; ++i) {
1132      if (i) OS << ",";
1133      OS << hexdigit((Contents[i] >> 4) & 0xF) << hexdigit(Contents[i] & 0xF);
1134    }
1135    OS << "] (" << Contents.size() << " bytes)";
1136    break;
1137  }
1138  case MCFragment::FT_Fill:  {
1139    const MCFillFragment *FF = cast<MCFillFragment>(this);
1140    OS << " Value:" << FF->getValue() << " ValueSize:" << FF->getValueSize()
1141       << " Size:" << FF->getSize();
1142    break;
1143  }
1144  case MCFragment::FT_Relaxable:  {
1145    const MCRelaxableFragment *F = cast<MCRelaxableFragment>(this);
1146    OS << "\n       ";
1147    OS << " Inst:";
1148    F->getInst().dump_pretty(OS);
1149    break;
1150  }
1151  case MCFragment::FT_Org:  {
1152    const MCOrgFragment *OF = cast<MCOrgFragment>(this);
1153    OS << "\n       ";
1154    OS << " Offset:" << OF->getOffset() << " Value:" << OF->getValue();
1155    break;
1156  }
1157  case MCFragment::FT_Dwarf:  {
1158    const MCDwarfLineAddrFragment *OF = cast<MCDwarfLineAddrFragment>(this);
1159    OS << "\n       ";
1160    OS << " AddrDelta:" << OF->getAddrDelta()
1161       << " LineDelta:" << OF->getLineDelta();
1162    break;
1163  }
1164  case MCFragment::FT_DwarfFrame:  {
1165    const MCDwarfCallFrameFragment *CF = cast<MCDwarfCallFrameFragment>(this);
1166    OS << "\n       ";
1167    OS << " AddrDelta:" << CF->getAddrDelta();
1168    break;
1169  }
1170  case MCFragment::FT_LEB: {
1171    const MCLEBFragment *LF = cast<MCLEBFragment>(this);
1172    OS << "\n       ";
1173    OS << " Value:" << LF->getValue() << " Signed:" << LF->isSigned();
1174    break;
1175  }
1176  }
1177  OS << ">";
1178}
1179
1180void MCSectionData::dump() {
1181  raw_ostream &OS = llvm::errs();
1182
1183  OS << "<MCSectionData";
1184  OS << " Alignment:" << getAlignment()
1185     << " Fragments:[\n      ";
1186  for (iterator it = begin(), ie = end(); it != ie; ++it) {
1187    if (it != begin()) OS << ",\n      ";
1188    it->dump();
1189  }
1190  OS << "]>";
1191}
1192
1193void MCSymbolData::dump() {
1194  raw_ostream &OS = llvm::errs();
1195
1196  OS << "<MCSymbolData Symbol:" << getSymbol()
1197     << " Fragment:" << getFragment() << " Offset:" << getOffset()
1198     << " Flags:" << getFlags() << " Index:" << getIndex();
1199  if (isCommon())
1200    OS << " (common, size:" << getCommonSize()
1201       << " align: " << getCommonAlignment() << ")";
1202  if (isExternal())
1203    OS << " (external)";
1204  if (isPrivateExtern())
1205    OS << " (private extern)";
1206  OS << ">";
1207}
1208
1209void MCAssembler::dump() {
1210  raw_ostream &OS = llvm::errs();
1211
1212  OS << "<MCAssembler\n";
1213  OS << "  Sections:[\n    ";
1214  for (iterator it = begin(), ie = end(); it != ie; ++it) {
1215    if (it != begin()) OS << ",\n    ";
1216    it->dump();
1217  }
1218  OS << "],\n";
1219  OS << "  Symbols:[";
1220
1221  for (symbol_iterator it = symbol_begin(), ie = symbol_end(); it != ie; ++it) {
1222    if (it != symbol_begin()) OS << ",\n           ";
1223    it->dump();
1224  }
1225  OS << "]>\n";
1226}
1227#endif
1228
1229// anchors for MC*Fragment vtables
1230void MCEncodedFragment::anchor() { }
1231void MCEncodedFragmentWithFixups::anchor() { }
1232void MCDataFragment::anchor() { }
1233void MCCompactEncodedInstFragment::anchor() { }
1234void MCRelaxableFragment::anchor() { }
1235void MCAlignFragment::anchor() { }
1236void MCFillFragment::anchor() { }
1237void MCOrgFragment::anchor() { }
1238void MCLEBFragment::anchor() { }
1239void MCDwarfLineAddrFragment::anchor() { }
1240void MCDwarfCallFrameFragment::anchor() { }
1241