MCAssembler.cpp revision 288943 
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#include "llvm/MC/MCAssembler.h"
11#include "llvm/ADT/Statistic.h"
12#include "llvm/ADT/StringExtras.h"
13#include "llvm/ADT/Twine.h"
14#include "llvm/MC/MCAsmBackend.h"
15#include "llvm/MC/MCAsmInfo.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/MCSectionELF.h"
25#include "llvm/MC/MCSymbol.h"
26#include "llvm/MC/MCValue.h"
27#include "llvm/Support/Debug.h"
28#include "llvm/Support/ErrorHandling.h"
29#include "llvm/Support/LEB128.h"
30#include "llvm/Support/TargetRegistry.h"
31#include "llvm/Support/raw_ostream.h"
32#include <tuple>
33using namespace llvm;
34
35#define DEBUG_TYPE "assembler"
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->isVirtualSection())
73      SectionOrder.push_back(&*it);
74  for (MCAssembler::iterator it = Asm.begin(), ie = Asm.end(); it != ie; ++it)
75    if (it->isVirtualSection())
76      SectionOrder.push_back(&*it);
77}
78
79bool MCAsmLayout::isFragmentValid(const MCFragment *F) const {
80  const MCSection *Sec = F->getParent();
81  const MCFragment *LastValid = LastValidFragment.lookup(Sec);
82  if (!LastValid)
83    return false;
84  assert(LastValid->getParent() == Sec);
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  LastValidFragment[F->getParent()] = F->getPrevNode();
96}
97
98void MCAsmLayout::ensureValid(const MCFragment *F) const {
99  MCSection *Sec = F->getParent();
100  MCFragment *Cur = LastValidFragment[Sec];
101  if (!Cur)
102    Cur = Sec->begin();
103  else
104    Cur = Cur->getNextNode();
105
106  // Advance the layout position until the fragment is valid.
107  while (!isFragmentValid(F)) {
108    assert(Cur && "Layout bookkeeping error");
109    const_cast<MCAsmLayout*>(this)->layoutFragment(Cur);
110    Cur = Cur->getNextNode();
111  }
112}
113
114uint64_t MCAsmLayout::getFragmentOffset(const MCFragment *F) const {
115  ensureValid(F);
116  assert(F->Offset != ~UINT64_C(0) && "Address not set!");
117  return F->Offset;
118}
119
120// Simple getSymbolOffset helper for the non-varibale case.
121static bool getLabelOffset(const MCAsmLayout &Layout, const MCSymbol &S,
122                           bool ReportError, uint64_t &Val) {
123  if (!S.getFragment()) {
124    if (ReportError)
125      report_fatal_error("unable to evaluate offset to undefined symbol '" +
126                         S.getName() + "'");
127    return false;
128  }
129  Val = Layout.getFragmentOffset(S.getFragment()) + S.getOffset();
130  return true;
131}
132
133static bool getSymbolOffsetImpl(const MCAsmLayout &Layout, const MCSymbol &S,
134                                bool ReportError, uint64_t &Val) {
135  if (!S.isVariable())
136    return getLabelOffset(Layout, S, ReportError, Val);
137
138  // If SD is a variable, evaluate it.
139  MCValue Target;
140  if (!S.getVariableValue()->evaluateAsRelocatable(Target, &Layout, nullptr))
141    report_fatal_error("unable to evaluate offset for variable '" +
142                       S.getName() + "'");
143
144  uint64_t Offset = Target.getConstant();
145
146  const MCSymbolRefExpr *A = Target.getSymA();
147  if (A) {
148    uint64_t ValA;
149    if (!getLabelOffset(Layout, A->getSymbol(), ReportError, ValA))
150      return false;
151    Offset += ValA;
152  }
153
154  const MCSymbolRefExpr *B = Target.getSymB();
155  if (B) {
156    uint64_t ValB;
157    if (!getLabelOffset(Layout, B->getSymbol(), ReportError, ValB))
158      return false;
159    Offset -= ValB;
160  }
161
162  Val = Offset;
163  return true;
164}
165
166bool MCAsmLayout::getSymbolOffset(const MCSymbol &S, uint64_t &Val) const {
167  return getSymbolOffsetImpl(*this, S, false, Val);
168}
169
170uint64_t MCAsmLayout::getSymbolOffset(const MCSymbol &S) const {
171  uint64_t Val;
172  getSymbolOffsetImpl(*this, S, true, Val);
173  return Val;
174}
175
176const MCSymbol *MCAsmLayout::getBaseSymbol(const MCSymbol &Symbol) const {
177  if (!Symbol.isVariable())
178    return &Symbol;
179
180  const MCExpr *Expr = Symbol.getVariableValue();
181  MCValue Value;
182  if (!Expr->evaluateAsValue(Value, *this))
183    llvm_unreachable("Invalid Expression");
184
185  const MCSymbolRefExpr *RefB = Value.getSymB();
186  if (RefB)
187    Assembler.getContext().reportFatalError(
188        SMLoc(), Twine("symbol '") + RefB->getSymbol().getName() +
189                     "' could not be evaluated in a subtraction expression");
190
191  const MCSymbolRefExpr *A = Value.getSymA();
192  if (!A)
193    return nullptr;
194
195  const MCSymbol &ASym = A->getSymbol();
196  const MCAssembler &Asm = getAssembler();
197  if (ASym.isCommon()) {
198    // FIXME: we should probably add a SMLoc to MCExpr.
199    Asm.getContext().reportFatalError(SMLoc(),
200                                "Common symbol " + ASym.getName() +
201                                    " cannot be used in assignment expr");
202  }
203
204  return &ASym;
205}
206
207uint64_t MCAsmLayout::getSectionAddressSize(const MCSection *Sec) const {
208  // The size is the last fragment's end offset.
209  const MCFragment &F = Sec->getFragmentList().back();
210  return getFragmentOffset(&F) + getAssembler().computeFragmentSize(*this, F);
211}
212
213uint64_t MCAsmLayout::getSectionFileSize(const MCSection *Sec) const {
214  // Virtual sections have no file size.
215  if (Sec->isVirtualSection())
216    return 0;
217
218  // Otherwise, the file size is the same as the address space size.
219  return getSectionAddressSize(Sec);
220}
221
222uint64_t llvm::computeBundlePadding(const MCAssembler &Assembler,
223                                    const MCFragment *F,
224                                    uint64_t FOffset, uint64_t FSize) {
225  uint64_t BundleSize = Assembler.getBundleAlignSize();
226  assert(BundleSize > 0 &&
227         "computeBundlePadding should only be called if bundling is enabled");
228  uint64_t BundleMask = BundleSize - 1;
229  uint64_t OffsetInBundle = FOffset & BundleMask;
230  uint64_t EndOfFragment = OffsetInBundle + FSize;
231
232  // There are two kinds of bundling restrictions:
233  //
234  // 1) For alignToBundleEnd(), add padding to ensure that the fragment will
235  //    *end* on a bundle boundary.
236  // 2) Otherwise, check if the fragment would cross a bundle boundary. If it
237  //    would, add padding until the end of the bundle so that the fragment
238  //    will start in a new one.
239  if (F->alignToBundleEnd()) {
240    // Three possibilities here:
241    //
242    // A) The fragment just happens to end at a bundle boundary, so we're good.
243    // B) The fragment ends before the current bundle boundary: pad it just
244    //    enough to reach the boundary.
245    // C) The fragment ends after the current bundle boundary: pad it until it
246    //    reaches the end of the next bundle boundary.
247    //
248    // Note: this code could be made shorter with some modulo trickery, but it's
249    // intentionally kept in its more explicit form for simplicity.
250    if (EndOfFragment == BundleSize)
251      return 0;
252    else if (EndOfFragment < BundleSize)
253      return BundleSize - EndOfFragment;
254    else { // EndOfFragment > BundleSize
255      return 2 * BundleSize - EndOfFragment;
256    }
257  } else if (OffsetInBundle > 0 && EndOfFragment > BundleSize)
258    return BundleSize - OffsetInBundle;
259  else
260    return 0;
261}
262
263/* *** */
264
265void ilist_node_traits<MCFragment>::deleteNode(MCFragment *V) {
266  V->destroy();
267}
268
269MCFragment::MCFragment() : Kind(FragmentType(~0)), HasInstructions(false),
270                           AlignToBundleEnd(false), BundlePadding(0) {
271}
272
273MCFragment::~MCFragment() { }
274
275MCFragment::MCFragment(FragmentType Kind, bool HasInstructions,
276                       uint8_t BundlePadding, MCSection *Parent)
277    : Kind(Kind), HasInstructions(HasInstructions), AlignToBundleEnd(false),
278      BundlePadding(BundlePadding), Parent(Parent), Atom(nullptr),
279      Offset(~UINT64_C(0)) {
280  if (Parent)
281    Parent->getFragmentList().push_back(this);
282}
283
284void MCFragment::destroy() {
285  // First check if we are the sentinal.
286  if (Kind == FragmentType(~0)) {
287    delete this;
288    return;
289  }
290
291  switch (Kind) {
292    case FT_Align:
293      delete cast<MCAlignFragment>(this);
294      return;
295    case FT_Data:
296      delete cast<MCDataFragment>(this);
297      return;
298    case FT_CompactEncodedInst:
299      delete cast<MCCompactEncodedInstFragment>(this);
300      return;
301    case FT_Fill:
302      delete cast<MCFillFragment>(this);
303      return;
304    case FT_Relaxable:
305      delete cast<MCRelaxableFragment>(this);
306      return;
307    case FT_Org:
308      delete cast<MCOrgFragment>(this);
309      return;
310    case FT_Dwarf:
311      delete cast<MCDwarfLineAddrFragment>(this);
312      return;
313    case FT_DwarfFrame:
314      delete cast<MCDwarfCallFrameFragment>(this);
315      return;
316    case FT_LEB:
317      delete cast<MCLEBFragment>(this);
318      return;
319    case FT_SafeSEH:
320      delete cast<MCSafeSEHFragment>(this);
321      return;
322  }
323}
324
325/* *** */
326
327MCAssembler::MCAssembler(MCContext &Context_, MCAsmBackend &Backend_,
328                         MCCodeEmitter &Emitter_, MCObjectWriter &Writer_,
329                         raw_ostream &OS_)
330    : Context(Context_), Backend(Backend_), Emitter(Emitter_), Writer(Writer_),
331      OS(OS_), BundleAlignSize(0), RelaxAll(false),
332      SubsectionsViaSymbols(false), ELFHeaderEFlags(0) {
333  VersionMinInfo.Major = 0; // Major version == 0 for "none specified"
334}
335
336MCAssembler::~MCAssembler() {
337}
338
339void MCAssembler::reset() {
340  Sections.clear();
341  Symbols.clear();
342  IndirectSymbols.clear();
343  DataRegions.clear();
344  LinkerOptions.clear();
345  FileNames.clear();
346  ThumbFuncs.clear();
347  BundleAlignSize = 0;
348  RelaxAll = false;
349  SubsectionsViaSymbols = false;
350  ELFHeaderEFlags = 0;
351  LOHContainer.reset();
352  VersionMinInfo.Major = 0;
353
354  // reset objects owned by us
355  getBackend().reset();
356  getEmitter().reset();
357  getWriter().reset();
358  getLOHContainer().reset();
359}
360
361bool MCAssembler::isThumbFunc(const MCSymbol *Symbol) const {
362  if (ThumbFuncs.count(Symbol))
363    return true;
364
365  if (!Symbol->isVariable())
366    return false;
367
368  // FIXME: It looks like gas supports some cases of the form "foo + 2". It
369  // is not clear if that is a bug or a feature.
370  const MCExpr *Expr = Symbol->getVariableValue();
371  const MCSymbolRefExpr *Ref = dyn_cast<MCSymbolRefExpr>(Expr);
372  if (!Ref)
373    return false;
374
375  if (Ref->getKind() != MCSymbolRefExpr::VK_None)
376    return false;
377
378  const MCSymbol &Sym = Ref->getSymbol();
379  if (!isThumbFunc(&Sym))
380    return false;
381
382  ThumbFuncs.insert(Symbol); // Cache it.
383  return true;
384}
385
386bool MCAssembler::isSymbolLinkerVisible(const MCSymbol &Symbol) const {
387  // Non-temporary labels should always be visible to the linker.
388  if (!Symbol.isTemporary())
389    return true;
390
391  // Absolute temporary labels are never visible.
392  if (!Symbol.isInSection())
393    return false;
394
395  if (Symbol.isUsedInReloc())
396    return true;
397
398  return false;
399}
400
401const MCSymbol *MCAssembler::getAtom(const MCSymbol &S) const {
402  // Linker visible symbols define atoms.
403  if (isSymbolLinkerVisible(S))
404    return &S;
405
406  // Absolute and undefined symbols have no defining atom.
407  if (!S.getFragment())
408    return nullptr;
409
410  // Non-linker visible symbols in sections which can't be atomized have no
411  // defining atom.
412  if (!getContext().getAsmInfo()->isSectionAtomizableBySymbols(
413          *S.getFragment()->getParent()))
414    return nullptr;
415
416  // Otherwise, return the atom for the containing fragment.
417  return S.getFragment()->getAtom();
418}
419
420bool MCAssembler::evaluateFixup(const MCAsmLayout &Layout,
421                                const MCFixup &Fixup, const MCFragment *DF,
422                                MCValue &Target, uint64_t &Value) const {
423  ++stats::evaluateFixup;
424
425  // FIXME: This code has some duplication with recordRelocation. We should
426  // probably merge the two into a single callback that tries to evaluate a
427  // fixup and records a relocation if one is needed.
428  const MCExpr *Expr = Fixup.getValue();
429  if (!Expr->evaluateAsRelocatable(Target, &Layout, &Fixup))
430    getContext().reportFatalError(Fixup.getLoc(), "expected relocatable expression");
431
432  bool IsPCRel = Backend.getFixupKindInfo(
433    Fixup.getKind()).Flags & MCFixupKindInfo::FKF_IsPCRel;
434
435  bool IsResolved;
436  if (IsPCRel) {
437    if (Target.getSymB()) {
438      IsResolved = false;
439    } else if (!Target.getSymA()) {
440      IsResolved = false;
441    } else {
442      const MCSymbolRefExpr *A = Target.getSymA();
443      const MCSymbol &SA = A->getSymbol();
444      if (A->getKind() != MCSymbolRefExpr::VK_None || SA.isUndefined()) {
445        IsResolved = false;
446      } else {
447        IsResolved = getWriter().isSymbolRefDifferenceFullyResolvedImpl(
448            *this, SA, *DF, false, true);
449      }
450    }
451  } else {
452    IsResolved = Target.isAbsolute();
453  }
454
455  Value = Target.getConstant();
456
457  if (const MCSymbolRefExpr *A = Target.getSymA()) {
458    const MCSymbol &Sym = A->getSymbol();
459    if (Sym.isDefined())
460      Value += Layout.getSymbolOffset(Sym);
461  }
462  if (const MCSymbolRefExpr *B = Target.getSymB()) {
463    const MCSymbol &Sym = B->getSymbol();
464    if (Sym.isDefined())
465      Value -= Layout.getSymbolOffset(Sym);
466  }
467
468
469  bool ShouldAlignPC = Backend.getFixupKindInfo(Fixup.getKind()).Flags &
470                         MCFixupKindInfo::FKF_IsAlignedDownTo32Bits;
471  assert((ShouldAlignPC ? IsPCRel : true) &&
472    "FKF_IsAlignedDownTo32Bits is only allowed on PC-relative fixups!");
473
474  if (IsPCRel) {
475    uint32_t Offset = Layout.getFragmentOffset(DF) + Fixup.getOffset();
476
477    // A number of ARM fixups in Thumb mode require that the effective PC
478    // address be determined as the 32-bit aligned version of the actual offset.
479    if (ShouldAlignPC) Offset &= ~0x3;
480    Value -= Offset;
481  }
482
483  // Let the backend adjust the fixup value if necessary, including whether
484  // we need a relocation.
485  Backend.processFixupValue(*this, Layout, Fixup, DF, Target, Value,
486                            IsResolved);
487
488  return IsResolved;
489}
490
491uint64_t MCAssembler::computeFragmentSize(const MCAsmLayout &Layout,
492                                          const MCFragment &F) const {
493  switch (F.getKind()) {
494  case MCFragment::FT_Data:
495    return cast<MCDataFragment>(F).getContents().size();
496  case MCFragment::FT_Relaxable:
497    return cast<MCRelaxableFragment>(F).getContents().size();
498  case MCFragment::FT_CompactEncodedInst:
499    return cast<MCCompactEncodedInstFragment>(F).getContents().size();
500  case MCFragment::FT_Fill:
501    return cast<MCFillFragment>(F).getSize();
502
503  case MCFragment::FT_LEB:
504    return cast<MCLEBFragment>(F).getContents().size();
505
506  case MCFragment::FT_SafeSEH:
507    return 4;
508
509  case MCFragment::FT_Align: {
510    const MCAlignFragment &AF = cast<MCAlignFragment>(F);
511    unsigned Offset = Layout.getFragmentOffset(&AF);
512    unsigned Size = OffsetToAlignment(Offset, AF.getAlignment());
513    // If we are padding with nops, force the padding to be larger than the
514    // minimum nop size.
515    if (Size > 0 && AF.hasEmitNops()) {
516      while (Size % getBackend().getMinimumNopSize())
517        Size += AF.getAlignment();
518    }
519    if (Size > AF.getMaxBytesToEmit())
520      return 0;
521    return Size;
522  }
523
524  case MCFragment::FT_Org: {
525    const MCOrgFragment &OF = cast<MCOrgFragment>(F);
526    int64_t TargetLocation;
527    if (!OF.getOffset().evaluateAsAbsolute(TargetLocation, Layout))
528      report_fatal_error("expected assembly-time absolute expression");
529
530    // FIXME: We need a way to communicate this error.
531    uint64_t FragmentOffset = Layout.getFragmentOffset(&OF);
532    int64_t Size = TargetLocation - FragmentOffset;
533    if (Size < 0 || Size >= 0x40000000)
534      report_fatal_error("invalid .org offset '" + Twine(TargetLocation) +
535                         "' (at offset '" + Twine(FragmentOffset) + "')");
536    return Size;
537  }
538
539  case MCFragment::FT_Dwarf:
540    return cast<MCDwarfLineAddrFragment>(F).getContents().size();
541  case MCFragment::FT_DwarfFrame:
542    return cast<MCDwarfCallFrameFragment>(F).getContents().size();
543  }
544
545  llvm_unreachable("invalid fragment kind");
546}
547
548void MCAsmLayout::layoutFragment(MCFragment *F) {
549  MCFragment *Prev = F->getPrevNode();
550
551  // We should never try to recompute something which is valid.
552  assert(!isFragmentValid(F) && "Attempt to recompute a valid fragment!");
553  // We should never try to compute the fragment layout if its predecessor
554  // isn't valid.
555  assert((!Prev || isFragmentValid(Prev)) &&
556         "Attempt to compute fragment before its predecessor!");
557
558  ++stats::FragmentLayouts;
559
560  // Compute fragment offset and size.
561  if (Prev)
562    F->Offset = Prev->Offset + getAssembler().computeFragmentSize(*this, *Prev);
563  else
564    F->Offset = 0;
565  LastValidFragment[F->getParent()] = F;
566
567  // If bundling is enabled and this fragment has instructions in it, it has to
568  // obey the bundling restrictions. With padding, we'll have:
569  //
570  //
571  //        BundlePadding
572  //             |||
573  // -------------------------------------
574  //   Prev  |##########|       F        |
575  // -------------------------------------
576  //                    ^
577  //                    |
578  //                    F->Offset
579  //
580  // The fragment's offset will point to after the padding, and its computed
581  // size won't include the padding.
582  //
583  // When the -mc-relax-all flag is used, we optimize bundling by writting the
584  // padding directly into fragments when the instructions are emitted inside
585  // the streamer. When the fragment is larger than the bundle size, we need to
586  // ensure that it's bundle aligned. This means that if we end up with
587  // multiple fragments, we must emit bundle padding between fragments.
588  //
589  // ".align N" is an example of a directive that introduces multiple
590  // fragments. We could add a special case to handle ".align N" by emitting
591  // within-fragment padding (which would produce less padding when N is less
592  // than the bundle size), but for now we don't.
593  //
594  if (Assembler.isBundlingEnabled() && F->hasInstructions()) {
595    assert(isa<MCEncodedFragment>(F) &&
596           "Only MCEncodedFragment implementations have instructions");
597    uint64_t FSize = Assembler.computeFragmentSize(*this, *F);
598
599    if (!Assembler.getRelaxAll() && FSize > Assembler.getBundleAlignSize())
600      report_fatal_error("Fragment can't be larger than a bundle size");
601
602    uint64_t RequiredBundlePadding = computeBundlePadding(Assembler, F,
603                                                          F->Offset, FSize);
604    if (RequiredBundlePadding > UINT8_MAX)
605      report_fatal_error("Padding cannot exceed 255 bytes");
606    F->setBundlePadding(static_cast<uint8_t>(RequiredBundlePadding));
607    F->Offset += RequiredBundlePadding;
608  }
609}
610
611void MCAssembler::registerSymbol(const MCSymbol &Symbol, bool *Created) {
612  bool New = !Symbol.isRegistered();
613  if (Created)
614    *Created = New;
615  if (New) {
616    Symbol.setIsRegistered(true);
617    Symbols.push_back(&Symbol);
618  }
619}
620
621void MCAssembler::writeFragmentPadding(const MCFragment &F, uint64_t FSize,
622                                       MCObjectWriter *OW) const {
623  // Should NOP padding be written out before this fragment?
624  unsigned BundlePadding = F.getBundlePadding();
625  if (BundlePadding > 0) {
626    assert(isBundlingEnabled() &&
627           "Writing bundle padding with disabled bundling");
628    assert(F.hasInstructions() &&
629           "Writing bundle padding for a fragment without instructions");
630
631    unsigned TotalLength = BundlePadding + static_cast<unsigned>(FSize);
632    if (F.alignToBundleEnd() && TotalLength > getBundleAlignSize()) {
633      // If the padding itself crosses a bundle boundary, it must be emitted
634      // in 2 pieces, since even nop instructions must not cross boundaries.
635      //             v--------------v   <- BundleAlignSize
636      //        v---------v             <- BundlePadding
637      // ----------------------------
638      // | Prev |####|####|    F    |
639      // ----------------------------
640      //        ^-------------------^   <- TotalLength
641      unsigned DistanceToBoundary = TotalLength - getBundleAlignSize();
642      if (!getBackend().writeNopData(DistanceToBoundary, OW))
643          report_fatal_error("unable to write NOP sequence of " +
644                             Twine(DistanceToBoundary) + " bytes");
645      BundlePadding -= DistanceToBoundary;
646    }
647    if (!getBackend().writeNopData(BundlePadding, OW))
648      report_fatal_error("unable to write NOP sequence of " +
649                         Twine(BundlePadding) + " bytes");
650  }
651}
652
653/// \brief Write the fragment \p F to the output file.
654static void writeFragment(const MCAssembler &Asm, const MCAsmLayout &Layout,
655                          const MCFragment &F) {
656  MCObjectWriter *OW = &Asm.getWriter();
657
658  // FIXME: Embed in fragments instead?
659  uint64_t FragmentSize = Asm.computeFragmentSize(Layout, F);
660
661  Asm.writeFragmentPadding(F, FragmentSize, OW);
662
663  // This variable (and its dummy usage) is to participate in the assert at
664  // the end of the function.
665  uint64_t Start = OW->getStream().tell();
666  (void) Start;
667
668  ++stats::EmittedFragments;
669
670  switch (F.getKind()) {
671  case MCFragment::FT_Align: {
672    ++stats::EmittedAlignFragments;
673    const MCAlignFragment &AF = cast<MCAlignFragment>(F);
674    assert(AF.getValueSize() && "Invalid virtual align in concrete fragment!");
675
676    uint64_t Count = FragmentSize / AF.getValueSize();
677
678    // FIXME: This error shouldn't actually occur (the front end should emit
679    // multiple .align directives to enforce the semantics it wants), but is
680    // severe enough that we want to report it. How to handle this?
681    if (Count * AF.getValueSize() != FragmentSize)
682      report_fatal_error("undefined .align directive, value size '" +
683                        Twine(AF.getValueSize()) +
684                        "' is not a divisor of padding size '" +
685                        Twine(FragmentSize) + "'");
686
687    // See if we are aligning with nops, and if so do that first to try to fill
688    // the Count bytes.  Then if that did not fill any bytes or there are any
689    // bytes left to fill use the Value and ValueSize to fill the rest.
690    // If we are aligning with nops, ask that target to emit the right data.
691    if (AF.hasEmitNops()) {
692      if (!Asm.getBackend().writeNopData(Count, OW))
693        report_fatal_error("unable to write nop sequence of " +
694                          Twine(Count) + " bytes");
695      break;
696    }
697
698    // Otherwise, write out in multiples of the value size.
699    for (uint64_t i = 0; i != Count; ++i) {
700      switch (AF.getValueSize()) {
701      default: llvm_unreachable("Invalid size!");
702      case 1: OW->write8 (uint8_t (AF.getValue())); break;
703      case 2: OW->write16(uint16_t(AF.getValue())); break;
704      case 4: OW->write32(uint32_t(AF.getValue())); break;
705      case 8: OW->write64(uint64_t(AF.getValue())); break;
706      }
707    }
708    break;
709  }
710
711  case MCFragment::FT_Data:
712    ++stats::EmittedDataFragments;
713    OW->writeBytes(cast<MCDataFragment>(F).getContents());
714    break;
715
716  case MCFragment::FT_Relaxable:
717    ++stats::EmittedRelaxableFragments;
718    OW->writeBytes(cast<MCRelaxableFragment>(F).getContents());
719    break;
720
721  case MCFragment::FT_CompactEncodedInst:
722    ++stats::EmittedCompactEncodedInstFragments;
723    OW->writeBytes(cast<MCCompactEncodedInstFragment>(F).getContents());
724    break;
725
726  case MCFragment::FT_Fill: {
727    ++stats::EmittedFillFragments;
728    const MCFillFragment &FF = cast<MCFillFragment>(F);
729
730    assert(FF.getValueSize() && "Invalid virtual align in concrete fragment!");
731
732    for (uint64_t i = 0, e = FF.getSize() / FF.getValueSize(); i != e; ++i) {
733      switch (FF.getValueSize()) {
734      default: llvm_unreachable("Invalid size!");
735      case 1: OW->write8 (uint8_t (FF.getValue())); break;
736      case 2: OW->write16(uint16_t(FF.getValue())); break;
737      case 4: OW->write32(uint32_t(FF.getValue())); break;
738      case 8: OW->write64(uint64_t(FF.getValue())); break;
739      }
740    }
741    break;
742  }
743
744  case MCFragment::FT_LEB: {
745    const MCLEBFragment &LF = cast<MCLEBFragment>(F);
746    OW->writeBytes(LF.getContents());
747    break;
748  }
749
750  case MCFragment::FT_SafeSEH: {
751    const MCSafeSEHFragment &SF = cast<MCSafeSEHFragment>(F);
752    OW->write32(SF.getSymbol()->getIndex());
753    break;
754  }
755
756  case MCFragment::FT_Org: {
757    ++stats::EmittedOrgFragments;
758    const MCOrgFragment &OF = cast<MCOrgFragment>(F);
759
760    for (uint64_t i = 0, e = FragmentSize; i != e; ++i)
761      OW->write8(uint8_t(OF.getValue()));
762
763    break;
764  }
765
766  case MCFragment::FT_Dwarf: {
767    const MCDwarfLineAddrFragment &OF = cast<MCDwarfLineAddrFragment>(F);
768    OW->writeBytes(OF.getContents());
769    break;
770  }
771  case MCFragment::FT_DwarfFrame: {
772    const MCDwarfCallFrameFragment &CF = cast<MCDwarfCallFrameFragment>(F);
773    OW->writeBytes(CF.getContents());
774    break;
775  }
776  }
777
778  assert(OW->getStream().tell() - Start == FragmentSize &&
779         "The stream should advance by fragment size");
780}
781
782void MCAssembler::writeSectionData(const MCSection *Sec,
783                                   const MCAsmLayout &Layout) const {
784  // Ignore virtual sections.
785  if (Sec->isVirtualSection()) {
786    assert(Layout.getSectionFileSize(Sec) == 0 && "Invalid size for section!");
787
788    // Check that contents are only things legal inside a virtual section.
789    for (MCSection::const_iterator it = Sec->begin(), ie = Sec->end(); it != ie;
790         ++it) {
791      switch (it->getKind()) {
792      default: llvm_unreachable("Invalid fragment in virtual section!");
793      case MCFragment::FT_Data: {
794        // Check that we aren't trying to write a non-zero contents (or fixups)
795        // into a virtual section. This is to support clients which use standard
796        // directives to fill the contents of virtual sections.
797        const MCDataFragment &DF = cast<MCDataFragment>(*it);
798        assert(DF.fixup_begin() == DF.fixup_end() &&
799               "Cannot have fixups in virtual section!");
800        for (unsigned i = 0, e = DF.getContents().size(); i != e; ++i)
801          if (DF.getContents()[i]) {
802            if (auto *ELFSec = dyn_cast<const MCSectionELF>(Sec))
803              report_fatal_error("non-zero initializer found in section '" +
804                  ELFSec->getSectionName() + "'");
805            else
806              report_fatal_error("non-zero initializer found in virtual section");
807          }
808        break;
809      }
810      case MCFragment::FT_Align:
811        // Check that we aren't trying to write a non-zero value into a virtual
812        // section.
813        assert((cast<MCAlignFragment>(it)->getValueSize() == 0 ||
814                cast<MCAlignFragment>(it)->getValue() == 0) &&
815               "Invalid align in virtual section!");
816        break;
817      case MCFragment::FT_Fill:
818        assert((cast<MCFillFragment>(it)->getValueSize() == 0 ||
819                cast<MCFillFragment>(it)->getValue() == 0) &&
820               "Invalid fill in virtual section!");
821        break;
822      }
823    }
824
825    return;
826  }
827
828  uint64_t Start = getWriter().getStream().tell();
829  (void)Start;
830
831  for (MCSection::const_iterator it = Sec->begin(), ie = Sec->end(); it != ie;
832       ++it)
833    writeFragment(*this, Layout, *it);
834
835  assert(getWriter().getStream().tell() - Start ==
836         Layout.getSectionAddressSize(Sec));
837}
838
839std::pair<uint64_t, bool> MCAssembler::handleFixup(const MCAsmLayout &Layout,
840                                                   MCFragment &F,
841                                                   const MCFixup &Fixup) {
842  // Evaluate the fixup.
843  MCValue Target;
844  uint64_t FixedValue;
845  bool IsPCRel = Backend.getFixupKindInfo(Fixup.getKind()).Flags &
846                 MCFixupKindInfo::FKF_IsPCRel;
847  if (!evaluateFixup(Layout, Fixup, &F, Target, FixedValue)) {
848    // The fixup was unresolved, we need a relocation. Inform the object
849    // writer of the relocation, and give it an opportunity to adjust the
850    // fixup value if need be.
851    getWriter().recordRelocation(*this, Layout, &F, Fixup, Target, IsPCRel,
852                                 FixedValue);
853  }
854  return std::make_pair(FixedValue, IsPCRel);
855}
856
857void MCAssembler::Finish() {
858  DEBUG_WITH_TYPE("mc-dump", {
859      llvm::errs() << "assembler backend - pre-layout\n--\n";
860      dump(); });
861
862  // Create the layout object.
863  MCAsmLayout Layout(*this);
864
865  // Create dummy fragments and assign section ordinals.
866  unsigned SectionIndex = 0;
867  for (MCAssembler::iterator it = begin(), ie = end(); it != ie; ++it) {
868    // Create dummy fragments to eliminate any empty sections, this simplifies
869    // layout.
870    if (it->getFragmentList().empty())
871      new MCDataFragment(&*it);
872
873    it->setOrdinal(SectionIndex++);
874  }
875
876  // Assign layout order indices to sections and fragments.
877  for (unsigned i = 0, e = Layout.getSectionOrder().size(); i != e; ++i) {
878    MCSection *Sec = Layout.getSectionOrder()[i];
879    Sec->setLayoutOrder(i);
880
881    unsigned FragmentIndex = 0;
882    for (MCSection::iterator iFrag = Sec->begin(), iFragEnd = Sec->end();
883         iFrag != iFragEnd; ++iFrag)
884      iFrag->setLayoutOrder(FragmentIndex++);
885  }
886
887  // Layout until everything fits.
888  while (layoutOnce(Layout))
889    continue;
890
891  DEBUG_WITH_TYPE("mc-dump", {
892      llvm::errs() << "assembler backend - post-relaxation\n--\n";
893      dump(); });
894
895  // Finalize the layout, including fragment lowering.
896  finishLayout(Layout);
897
898  DEBUG_WITH_TYPE("mc-dump", {
899      llvm::errs() << "assembler backend - final-layout\n--\n";
900      dump(); });
901
902  uint64_t StartOffset = OS.tell();
903
904  // Allow the object writer a chance to perform post-layout binding (for
905  // example, to set the index fields in the symbol data).
906  getWriter().executePostLayoutBinding(*this, Layout);
907
908  // Evaluate and apply the fixups, generating relocation entries as necessary.
909  for (MCAssembler::iterator it = begin(), ie = end(); it != ie; ++it) {
910    for (MCSection::iterator it2 = it->begin(), ie2 = it->end(); it2 != ie2;
911         ++it2) {
912      MCEncodedFragment *F = dyn_cast<MCEncodedFragment>(it2);
913      // Data and relaxable fragments both have fixups.  So only process
914      // those here.
915      // FIXME: Is there a better way to do this?  MCEncodedFragmentWithFixups
916      // being templated makes this tricky.
917      if (!F || isa<MCCompactEncodedInstFragment>(F))
918        continue;
919      ArrayRef<MCFixup> Fixups;
920      MutableArrayRef<char> Contents;
921      if (auto *FragWithFixups = dyn_cast<MCDataFragment>(F)) {
922        Fixups = FragWithFixups->getFixups();
923        Contents = FragWithFixups->getContents();
924      } else if (auto *FragWithFixups = dyn_cast<MCRelaxableFragment>(F)) {
925        Fixups = FragWithFixups->getFixups();
926        Contents = FragWithFixups->getContents();
927      } else
928        llvm_unreachable("Unknown fragment with fixups!");
929      for (const MCFixup &Fixup : Fixups) {
930        uint64_t FixedValue;
931        bool IsPCRel;
932        std::tie(FixedValue, IsPCRel) = handleFixup(Layout, *F, Fixup);
933        getBackend().applyFixup(Fixup, Contents.data(),
934                                Contents.size(), FixedValue, IsPCRel);
935      }
936    }
937  }
938
939  // Write the object file.
940  getWriter().writeObject(*this, Layout);
941
942  stats::ObjectBytes += OS.tell() - StartOffset;
943}
944
945bool MCAssembler::fixupNeedsRelaxation(const MCFixup &Fixup,
946                                       const MCRelaxableFragment *DF,
947                                       const MCAsmLayout &Layout) const {
948  MCValue Target;
949  uint64_t Value;
950  bool Resolved = evaluateFixup(Layout, Fixup, DF, Target, Value);
951  return getBackend().fixupNeedsRelaxationAdvanced(Fixup, Resolved, Value, DF,
952                                                   Layout);
953}
954
955bool MCAssembler::fragmentNeedsRelaxation(const MCRelaxableFragment *F,
956                                          const MCAsmLayout &Layout) const {
957  // If this inst doesn't ever need relaxation, ignore it. This occurs when we
958  // are intentionally pushing out inst fragments, or because we relaxed a
959  // previous instruction to one that doesn't need relaxation.
960  if (!getBackend().mayNeedRelaxation(F->getInst()))
961    return false;
962
963  for (MCRelaxableFragment::const_fixup_iterator it = F->fixup_begin(),
964       ie = F->fixup_end(); it != ie; ++it)
965    if (fixupNeedsRelaxation(*it, F, Layout))
966      return true;
967
968  return false;
969}
970
971bool MCAssembler::relaxInstruction(MCAsmLayout &Layout,
972                                   MCRelaxableFragment &F) {
973  if (!fragmentNeedsRelaxation(&F, Layout))
974    return false;
975
976  ++stats::RelaxedInstructions;
977
978  // FIXME-PERF: We could immediately lower out instructions if we can tell
979  // they are fully resolved, to avoid retesting on later passes.
980
981  // Relax the fragment.
982
983  MCInst Relaxed;
984  getBackend().relaxInstruction(F.getInst(), Relaxed);
985
986  // Encode the new instruction.
987  //
988  // FIXME-PERF: If it matters, we could let the target do this. It can
989  // probably do so more efficiently in many cases.
990  SmallVector<MCFixup, 4> Fixups;
991  SmallString<256> Code;
992  raw_svector_ostream VecOS(Code);
993  getEmitter().encodeInstruction(Relaxed, VecOS, Fixups, F.getSubtargetInfo());
994  VecOS.flush();
995
996  // Update the fragment.
997  F.setInst(Relaxed);
998  F.getContents() = Code;
999  F.getFixups() = Fixups;
1000
1001  return true;
1002}
1003
1004bool MCAssembler::relaxLEB(MCAsmLayout &Layout, MCLEBFragment &LF) {
1005  uint64_t OldSize = LF.getContents().size();
1006  int64_t Value;
1007  bool Abs = LF.getValue().evaluateKnownAbsolute(Value, Layout);
1008  if (!Abs)
1009    report_fatal_error("sleb128 and uleb128 expressions must be absolute");
1010  SmallString<8> &Data = LF.getContents();
1011  Data.clear();
1012  raw_svector_ostream OSE(Data);
1013  if (LF.isSigned())
1014    encodeSLEB128(Value, OSE);
1015  else
1016    encodeULEB128(Value, OSE);
1017  OSE.flush();
1018  return OldSize != LF.getContents().size();
1019}
1020
1021bool MCAssembler::relaxDwarfLineAddr(MCAsmLayout &Layout,
1022                                     MCDwarfLineAddrFragment &DF) {
1023  MCContext &Context = Layout.getAssembler().getContext();
1024  uint64_t OldSize = DF.getContents().size();
1025  int64_t AddrDelta;
1026  bool Abs = DF.getAddrDelta().evaluateKnownAbsolute(AddrDelta, Layout);
1027  assert(Abs && "We created a line delta with an invalid expression");
1028  (void) Abs;
1029  int64_t LineDelta;
1030  LineDelta = DF.getLineDelta();
1031  SmallString<8> &Data = DF.getContents();
1032  Data.clear();
1033  raw_svector_ostream OSE(Data);
1034  MCDwarfLineAddr::Encode(Context, LineDelta, AddrDelta, OSE);
1035  OSE.flush();
1036  return OldSize != Data.size();
1037}
1038
1039bool MCAssembler::relaxDwarfCallFrameFragment(MCAsmLayout &Layout,
1040                                              MCDwarfCallFrameFragment &DF) {
1041  MCContext &Context = Layout.getAssembler().getContext();
1042  uint64_t OldSize = DF.getContents().size();
1043  int64_t AddrDelta;
1044  bool Abs = DF.getAddrDelta().evaluateKnownAbsolute(AddrDelta, Layout);
1045  assert(Abs && "We created call frame with an invalid expression");
1046  (void) Abs;
1047  SmallString<8> &Data = DF.getContents();
1048  Data.clear();
1049  raw_svector_ostream OSE(Data);
1050  MCDwarfFrameEmitter::EncodeAdvanceLoc(Context, AddrDelta, OSE);
1051  OSE.flush();
1052  return OldSize != Data.size();
1053}
1054
1055bool MCAssembler::layoutSectionOnce(MCAsmLayout &Layout, MCSection &Sec) {
1056  // Holds the first fragment which needed relaxing during this layout. It will
1057  // remain NULL if none were relaxed.
1058  // When a fragment is relaxed, all the fragments following it should get
1059  // invalidated because their offset is going to change.
1060  MCFragment *FirstRelaxedFragment = nullptr;
1061
1062  // Attempt to relax all the fragments in the section.
1063  for (MCSection::iterator I = Sec.begin(), IE = Sec.end(); I != IE; ++I) {
1064    // Check if this is a fragment that needs relaxation.
1065    bool RelaxedFrag = false;
1066    switch(I->getKind()) {
1067    default:
1068      break;
1069    case MCFragment::FT_Relaxable:
1070      assert(!getRelaxAll() &&
1071             "Did not expect a MCRelaxableFragment in RelaxAll mode");
1072      RelaxedFrag = relaxInstruction(Layout, *cast<MCRelaxableFragment>(I));
1073      break;
1074    case MCFragment::FT_Dwarf:
1075      RelaxedFrag = relaxDwarfLineAddr(Layout,
1076                                       *cast<MCDwarfLineAddrFragment>(I));
1077      break;
1078    case MCFragment::FT_DwarfFrame:
1079      RelaxedFrag =
1080        relaxDwarfCallFrameFragment(Layout,
1081                                    *cast<MCDwarfCallFrameFragment>(I));
1082      break;
1083    case MCFragment::FT_LEB:
1084      RelaxedFrag = relaxLEB(Layout, *cast<MCLEBFragment>(I));
1085      break;
1086    }
1087    if (RelaxedFrag && !FirstRelaxedFragment)
1088      FirstRelaxedFragment = I;
1089  }
1090  if (FirstRelaxedFragment) {
1091    Layout.invalidateFragmentsFrom(FirstRelaxedFragment);
1092    return true;
1093  }
1094  return false;
1095}
1096
1097bool MCAssembler::layoutOnce(MCAsmLayout &Layout) {
1098  ++stats::RelaxationSteps;
1099
1100  bool WasRelaxed = false;
1101  for (iterator it = begin(), ie = end(); it != ie; ++it) {
1102    MCSection &Sec = *it;
1103    while (layoutSectionOnce(Layout, Sec))
1104      WasRelaxed = true;
1105  }
1106
1107  return WasRelaxed;
1108}
1109
1110void MCAssembler::finishLayout(MCAsmLayout &Layout) {
1111  // The layout is done. Mark every fragment as valid.
1112  for (unsigned int i = 0, n = Layout.getSectionOrder().size(); i != n; ++i) {
1113    Layout.getFragmentOffset(&*Layout.getSectionOrder()[i]->rbegin());
1114  }
1115}
1116
1117// Debugging methods
1118
1119namespace llvm {
1120
1121raw_ostream &operator<<(raw_ostream &OS, const MCFixup &AF) {
1122  OS << "<MCFixup" << " Offset:" << AF.getOffset()
1123     << " Value:" << *AF.getValue()
1124     << " Kind:" << AF.getKind() << ">";
1125  return OS;
1126}
1127
1128}
1129
1130#if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
1131void MCFragment::dump() {
1132  raw_ostream &OS = llvm::errs();
1133
1134  OS << "<";
1135  switch (getKind()) {
1136  case MCFragment::FT_Align: OS << "MCAlignFragment"; break;
1137  case MCFragment::FT_Data:  OS << "MCDataFragment"; break;
1138  case MCFragment::FT_CompactEncodedInst:
1139    OS << "MCCompactEncodedInstFragment"; break;
1140  case MCFragment::FT_Fill:  OS << "MCFillFragment"; break;
1141  case MCFragment::FT_Relaxable:  OS << "MCRelaxableFragment"; break;
1142  case MCFragment::FT_Org:   OS << "MCOrgFragment"; break;
1143  case MCFragment::FT_Dwarf: OS << "MCDwarfFragment"; break;
1144  case MCFragment::FT_DwarfFrame: OS << "MCDwarfCallFrameFragment"; break;
1145  case MCFragment::FT_LEB:   OS << "MCLEBFragment"; break;
1146  case MCFragment::FT_SafeSEH:    OS << "MCSafeSEHFragment"; break;
1147  }
1148
1149  OS << "<MCFragment " << (void*) this << " LayoutOrder:" << LayoutOrder
1150     << " Offset:" << Offset
1151     << " HasInstructions:" << hasInstructions()
1152     << " BundlePadding:" << static_cast<unsigned>(getBundlePadding()) << ">";
1153
1154  switch (getKind()) {
1155  case MCFragment::FT_Align: {
1156    const MCAlignFragment *AF = cast<MCAlignFragment>(this);
1157    if (AF->hasEmitNops())
1158      OS << " (emit nops)";
1159    OS << "\n       ";
1160    OS << " Alignment:" << AF->getAlignment()
1161       << " Value:" << AF->getValue() << " ValueSize:" << AF->getValueSize()
1162       << " MaxBytesToEmit:" << AF->getMaxBytesToEmit() << ">";
1163    break;
1164  }
1165  case MCFragment::FT_Data:  {
1166    const MCDataFragment *DF = cast<MCDataFragment>(this);
1167    OS << "\n       ";
1168    OS << " Contents:[";
1169    const SmallVectorImpl<char> &Contents = DF->getContents();
1170    for (unsigned i = 0, e = Contents.size(); i != e; ++i) {
1171      if (i) OS << ",";
1172      OS << hexdigit((Contents[i] >> 4) & 0xF) << hexdigit(Contents[i] & 0xF);
1173    }
1174    OS << "] (" << Contents.size() << " bytes)";
1175
1176    if (DF->fixup_begin() != DF->fixup_end()) {
1177      OS << ",\n       ";
1178      OS << " Fixups:[";
1179      for (MCDataFragment::const_fixup_iterator it = DF->fixup_begin(),
1180             ie = DF->fixup_end(); it != ie; ++it) {
1181        if (it != DF->fixup_begin()) OS << ",\n                ";
1182        OS << *it;
1183      }
1184      OS << "]";
1185    }
1186    break;
1187  }
1188  case MCFragment::FT_CompactEncodedInst: {
1189    const MCCompactEncodedInstFragment *CEIF =
1190      cast<MCCompactEncodedInstFragment>(this);
1191    OS << "\n       ";
1192    OS << " Contents:[";
1193    const SmallVectorImpl<char> &Contents = CEIF->getContents();
1194    for (unsigned i = 0, e = Contents.size(); i != e; ++i) {
1195      if (i) OS << ",";
1196      OS << hexdigit((Contents[i] >> 4) & 0xF) << hexdigit(Contents[i] & 0xF);
1197    }
1198    OS << "] (" << Contents.size() << " bytes)";
1199    break;
1200  }
1201  case MCFragment::FT_Fill:  {
1202    const MCFillFragment *FF = cast<MCFillFragment>(this);
1203    OS << " Value:" << FF->getValue() << " ValueSize:" << FF->getValueSize()
1204       << " Size:" << FF->getSize();
1205    break;
1206  }
1207  case MCFragment::FT_Relaxable:  {
1208    const MCRelaxableFragment *F = cast<MCRelaxableFragment>(this);
1209    OS << "\n       ";
1210    OS << " Inst:";
1211    F->getInst().dump_pretty(OS);
1212    break;
1213  }
1214  case MCFragment::FT_Org:  {
1215    const MCOrgFragment *OF = cast<MCOrgFragment>(this);
1216    OS << "\n       ";
1217    OS << " Offset:" << OF->getOffset() << " Value:" << OF->getValue();
1218    break;
1219  }
1220  case MCFragment::FT_Dwarf:  {
1221    const MCDwarfLineAddrFragment *OF = cast<MCDwarfLineAddrFragment>(this);
1222    OS << "\n       ";
1223    OS << " AddrDelta:" << OF->getAddrDelta()
1224       << " LineDelta:" << OF->getLineDelta();
1225    break;
1226  }
1227  case MCFragment::FT_DwarfFrame:  {
1228    const MCDwarfCallFrameFragment *CF = cast<MCDwarfCallFrameFragment>(this);
1229    OS << "\n       ";
1230    OS << " AddrDelta:" << CF->getAddrDelta();
1231    break;
1232  }
1233  case MCFragment::FT_LEB: {
1234    const MCLEBFragment *LF = cast<MCLEBFragment>(this);
1235    OS << "\n       ";
1236    OS << " Value:" << LF->getValue() << " Signed:" << LF->isSigned();
1237    break;
1238  }
1239  case MCFragment::FT_SafeSEH: {
1240    const MCSafeSEHFragment *F = cast<MCSafeSEHFragment>(this);
1241    OS << "\n       ";
1242    OS << " Sym:" << F->getSymbol();
1243    break;
1244  }
1245  }
1246  OS << ">";
1247}
1248
1249void MCAssembler::dump() {
1250  raw_ostream &OS = llvm::errs();
1251
1252  OS << "<MCAssembler\n";
1253  OS << "  Sections:[\n    ";
1254  for (iterator it = begin(), ie = end(); it != ie; ++it) {
1255    if (it != begin()) OS << ",\n    ";
1256    it->dump();
1257  }
1258  OS << "],\n";
1259  OS << "  Symbols:[";
1260
1261  for (symbol_iterator it = symbol_begin(), ie = symbol_end(); it != ie; ++it) {
1262    if (it != symbol_begin()) OS << ",\n           ";
1263    OS << "(";
1264    it->dump();
1265    OS << ", Index:" << it->getIndex() << ", ";
1266    OS << ")";
1267  }
1268  OS << "]>\n";
1269}
1270#endif
1271