MCAssembler.cpp revision dce4a407a24b04eebc6a376f8e62b41aaa7b071f 
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/MCAsmLayout.h"
16#include "llvm/MC/MCCodeEmitter.h"
17#include "llvm/MC/MCContext.h"
18#include "llvm/MC/MCDwarf.h"
19#include "llvm/MC/MCExpr.h"
20#include "llvm/MC/MCFixupKindInfo.h"
21#include "llvm/MC/MCObjectWriter.h"
22#include "llvm/MC/MCSection.h"
23#include "llvm/MC/MCSymbol.h"
24#include "llvm/MC/MCValue.h"
25#include "llvm/Support/Debug.h"
26#include "llvm/Support/ErrorHandling.h"
27#include "llvm/Support/LEB128.h"
28#include "llvm/Support/TargetRegistry.h"
29#include "llvm/Support/raw_ostream.h"
30#include <tuple>
31using namespace llvm;
32
33#define DEBUG_TYPE "assembler"
34
35namespace {
36namespace stats {
37STATISTIC(EmittedFragments, "Number of emitted assembler fragments - total");
38STATISTIC(EmittedRelaxableFragments,
39          "Number of emitted assembler fragments - relaxable");
40STATISTIC(EmittedDataFragments,
41          "Number of emitted assembler fragments - data");
42STATISTIC(EmittedCompactEncodedInstFragments,
43          "Number of emitted assembler fragments - compact encoded inst");
44STATISTIC(EmittedAlignFragments,
45          "Number of emitted assembler fragments - align");
46STATISTIC(EmittedFillFragments,
47          "Number of emitted assembler fragments - fill");
48STATISTIC(EmittedOrgFragments,
49          "Number of emitted assembler fragments - org");
50STATISTIC(evaluateFixup, "Number of evaluated fixups");
51STATISTIC(FragmentLayouts, "Number of fragment layouts");
52STATISTIC(ObjectBytes, "Number of emitted object file bytes");
53STATISTIC(RelaxationSteps, "Number of assembler layout and relaxation steps");
54STATISTIC(RelaxedInstructions, "Number of relaxed instructions");
55}
56}
57
58// FIXME FIXME FIXME: There are number of places in this file where we convert
59// what is a 64-bit assembler value used for computation into a value in the
60// object file, which may truncate it. We should detect that truncation where
61// invalid and report errors back.
62
63/* *** */
64
65MCAsmLayout::MCAsmLayout(MCAssembler &Asm)
66  : Assembler(Asm), LastValidFragment()
67 {
68  // Compute the section layout order. Virtual sections must go last.
69  for (MCAssembler::iterator it = Asm.begin(), ie = Asm.end(); it != ie; ++it)
70    if (!it->getSection().isVirtualSection())
71      SectionOrder.push_back(&*it);
72  for (MCAssembler::iterator it = Asm.begin(), ie = Asm.end(); it != ie; ++it)
73    if (it->getSection().isVirtualSection())
74      SectionOrder.push_back(&*it);
75}
76
77bool MCAsmLayout::isFragmentValid(const MCFragment *F) const {
78  const MCSectionData &SD = *F->getParent();
79  const MCFragment *LastValid = LastValidFragment.lookup(&SD);
80  if (!LastValid)
81    return false;
82  assert(LastValid->getParent() == F->getParent());
83  return F->getLayoutOrder() <= LastValid->getLayoutOrder();
84}
85
86void MCAsmLayout::invalidateFragmentsFrom(MCFragment *F) {
87  // If this fragment wasn't already valid, we don't need to do anything.
88  if (!isFragmentValid(F))
89    return;
90
91  // Otherwise, reset the last valid fragment to the previous fragment
92  // (if this is the first fragment, it will be NULL).
93  const MCSectionData &SD = *F->getParent();
94  LastValidFragment[&SD] = F->getPrevNode();
95}
96
97void MCAsmLayout::ensureValid(const MCFragment *F) const {
98  MCSectionData &SD = *F->getParent();
99
100  MCFragment *Cur = LastValidFragment[&SD];
101  if (!Cur)
102    Cur = &*SD.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 MCSymbolData &SD,
122                           bool ReportError, uint64_t &Val) {
123  if (!SD.getFragment()) {
124    if (ReportError)
125      report_fatal_error("unable to evaluate offset to undefined symbol '" +
126                         SD.getSymbol().getName() + "'");
127    return false;
128  }
129  Val = Layout.getFragmentOffset(SD.getFragment()) + SD.getOffset();
130  return true;
131}
132
133static bool getSymbolOffsetImpl(const MCAsmLayout &Layout,
134                                const MCSymbolData *SD, bool ReportError,
135                                uint64_t &Val) {
136  const MCSymbol &S = SD->getSymbol();
137
138  if (!S.isVariable())
139    return getLabelOffset(Layout, *SD, ReportError, Val);
140
141  // If SD is a variable, evaluate it.
142  MCValue Target;
143  if (!S.getVariableValue()->EvaluateAsValue(Target, &Layout))
144    report_fatal_error("unable to evaluate offset for variable '" +
145                       S.getName() + "'");
146
147  uint64_t Offset = Target.getConstant();
148
149  const MCAssembler &Asm = Layout.getAssembler();
150
151  const MCSymbolRefExpr *A = Target.getSymA();
152  if (A) {
153    uint64_t ValA;
154    if (!getLabelOffset(Layout, Asm.getSymbolData(A->getSymbol()), ReportError,
155                        ValA))
156      return false;
157    Offset += ValA;
158  }
159
160  const MCSymbolRefExpr *B = Target.getSymB();
161  if (B) {
162    uint64_t ValB;
163    if (!getLabelOffset(Layout, Asm.getSymbolData(B->getSymbol()), ReportError,
164                        ValB))
165      return false;
166    Offset -= ValB;
167  }
168
169  Val = Offset;
170  return true;
171}
172
173bool MCAsmLayout::getSymbolOffset(const MCSymbolData *SD, uint64_t &Val) const {
174  return getSymbolOffsetImpl(*this, SD, false, Val);
175}
176
177uint64_t MCAsmLayout::getSymbolOffset(const MCSymbolData *SD) const {
178  uint64_t Val;
179  getSymbolOffsetImpl(*this, SD, true, Val);
180  return Val;
181}
182
183const MCSymbol *MCAsmLayout::getBaseSymbol(const MCSymbol &Symbol) const {
184  if (!Symbol.isVariable())
185    return &Symbol;
186
187  const MCExpr *Expr = Symbol.getVariableValue();
188  MCValue Value;
189  if (!Expr->EvaluateAsValue(Value, this))
190    llvm_unreachable("Invalid Expression");
191
192  const MCSymbolRefExpr *RefB = Value.getSymB();
193  if (RefB)
194    Assembler.getContext().FatalError(
195        SMLoc(), Twine("symbol '") + RefB->getSymbol().getName() +
196                     "' could not be evaluated in a subtraction expression");
197
198  const MCSymbolRefExpr *A = Value.getSymA();
199  if (!A)
200    return nullptr;
201
202  return &A->getSymbol();
203}
204
205uint64_t MCAsmLayout::getSectionAddressSize(const MCSectionData *SD) const {
206  // The size is the last fragment's end offset.
207  const MCFragment &F = SD->getFragmentList().back();
208  return getFragmentOffset(&F) + getAssembler().computeFragmentSize(*this, F);
209}
210
211uint64_t MCAsmLayout::getSectionFileSize(const MCSectionData *SD) const {
212  // Virtual sections have no file size.
213  if (SD->getSection().isVirtualSection())
214    return 0;
215
216  // Otherwise, the file size is the same as the address space size.
217  return getSectionAddressSize(SD);
218}
219
220uint64_t MCAsmLayout::computeBundlePadding(const MCFragment *F,
221                                           uint64_t FOffset, uint64_t FSize) {
222  uint64_t BundleSize = Assembler.getBundleAlignSize();
223  assert(BundleSize > 0 &&
224         "computeBundlePadding should only be called if bundling is enabled");
225  uint64_t BundleMask = BundleSize - 1;
226  uint64_t OffsetInBundle = FOffset & BundleMask;
227  uint64_t EndOfFragment = OffsetInBundle + FSize;
228
229  // There are two kinds of bundling restrictions:
230  //
231  // 1) For alignToBundleEnd(), add padding to ensure that the fragment will
232  //    *end* on a bundle boundary.
233  // 2) Otherwise, check if the fragment would cross a bundle boundary. If it
234  //    would, add padding until the end of the bundle so that the fragment
235  //    will start in a new one.
236  if (F->alignToBundleEnd()) {
237    // Three possibilities here:
238    //
239    // A) The fragment just happens to end at a bundle boundary, so we're good.
240    // B) The fragment ends before the current bundle boundary: pad it just
241    //    enough to reach the boundary.
242    // C) The fragment ends after the current bundle boundary: pad it until it
243    //    reaches the end of the next bundle boundary.
244    //
245    // Note: this code could be made shorter with some modulo trickery, but it's
246    // intentionally kept in its more explicit form for simplicity.
247    if (EndOfFragment == BundleSize)
248      return 0;
249    else if (EndOfFragment < BundleSize)
250      return BundleSize - EndOfFragment;
251    else { // EndOfFragment > BundleSize
252      return 2 * BundleSize - EndOfFragment;
253    }
254  } else if (EndOfFragment > BundleSize)
255    return BundleSize - OffsetInBundle;
256  else
257    return 0;
258}
259
260/* *** */
261
262MCFragment::MCFragment() : Kind(FragmentType(~0)) {
263}
264
265MCFragment::~MCFragment() {
266}
267
268MCFragment::MCFragment(FragmentType _Kind, MCSectionData *_Parent)
269  : Kind(_Kind), Parent(_Parent), Atom(nullptr), Offset(~UINT64_C(0))
270{
271  if (Parent)
272    Parent->getFragmentList().push_back(this);
273}
274
275/* *** */
276
277MCEncodedFragment::~MCEncodedFragment() {
278}
279
280/* *** */
281
282MCEncodedFragmentWithFixups::~MCEncodedFragmentWithFixups() {
283}
284
285/* *** */
286
287MCSectionData::MCSectionData() : Section(nullptr) {}
288
289MCSectionData::MCSectionData(const MCSection &_Section, MCAssembler *A)
290  : Section(&_Section),
291    Ordinal(~UINT32_C(0)),
292    Alignment(1),
293    BundleLockState(NotBundleLocked), BundleGroupBeforeFirstInst(false),
294    HasInstructions(false)
295{
296  if (A)
297    A->getSectionList().push_back(this);
298}
299
300MCSectionData::iterator
301MCSectionData::getSubsectionInsertionPoint(unsigned Subsection) {
302  if (Subsection == 0 && SubsectionFragmentMap.empty())
303    return end();
304
305  SmallVectorImpl<std::pair<unsigned, MCFragment *> >::iterator MI =
306    std::lower_bound(SubsectionFragmentMap.begin(), SubsectionFragmentMap.end(),
307                     std::make_pair(Subsection, (MCFragment *)nullptr));
308  bool ExactMatch = false;
309  if (MI != SubsectionFragmentMap.end()) {
310    ExactMatch = MI->first == Subsection;
311    if (ExactMatch)
312      ++MI;
313  }
314  iterator IP;
315  if (MI == SubsectionFragmentMap.end())
316    IP = end();
317  else
318    IP = MI->second;
319  if (!ExactMatch && Subsection != 0) {
320    // The GNU as documentation claims that subsections have an alignment of 4,
321    // although this appears not to be the case.
322    MCFragment *F = new MCDataFragment();
323    SubsectionFragmentMap.insert(MI, std::make_pair(Subsection, F));
324    getFragmentList().insert(IP, F);
325    F->setParent(this);
326  }
327  return IP;
328}
329
330/* *** */
331
332MCSymbolData::MCSymbolData() : Symbol(nullptr) {}
333
334MCSymbolData::MCSymbolData(const MCSymbol &_Symbol, MCFragment *_Fragment,
335                           uint64_t _Offset, MCAssembler *A)
336  : Symbol(&_Symbol), Fragment(_Fragment), Offset(_Offset),
337    IsExternal(false), IsPrivateExtern(false),
338    CommonSize(0), SymbolSize(nullptr), CommonAlign(0),
339    Flags(0), Index(0)
340{
341  if (A)
342    A->getSymbolList().push_back(this);
343}
344
345/* *** */
346
347MCAssembler::MCAssembler(MCContext &Context_, MCAsmBackend &Backend_,
348                         MCCodeEmitter &Emitter_, MCObjectWriter &Writer_,
349                         raw_ostream &OS_)
350  : Context(Context_), Backend(Backend_), Emitter(Emitter_), Writer(Writer_),
351    OS(OS_), BundleAlignSize(0), RelaxAll(false), NoExecStack(false),
352    SubsectionsViaSymbols(false), ELFHeaderEFlags(0) {
353  VersionMinInfo.Major = 0; // Major version == 0 for "none specified"
354}
355
356MCAssembler::~MCAssembler() {
357}
358
359void MCAssembler::reset() {
360  Sections.clear();
361  Symbols.clear();
362  SectionMap.clear();
363  SymbolMap.clear();
364  IndirectSymbols.clear();
365  DataRegions.clear();
366  ThumbFuncs.clear();
367  RelaxAll = false;
368  NoExecStack = false;
369  SubsectionsViaSymbols = false;
370  ELFHeaderEFlags = 0;
371
372  // reset objects owned by us
373  getBackend().reset();
374  getEmitter().reset();
375  getWriter().reset();
376  getLOHContainer().reset();
377}
378
379bool MCAssembler::isThumbFunc(const MCSymbol *Symbol) const {
380  if (ThumbFuncs.count(Symbol))
381    return true;
382
383  if (!Symbol->isVariable())
384    return false;
385
386  // FIXME: It looks like gas supports some cases of the form "foo + 2". It
387  // is not clear if that is a bug or a feature.
388  const MCExpr *Expr = Symbol->getVariableValue();
389  const MCSymbolRefExpr *Ref = dyn_cast<MCSymbolRefExpr>(Expr);
390  if (!Ref)
391    return false;
392
393  if (Ref->getKind() != MCSymbolRefExpr::VK_None)
394    return false;
395
396  const MCSymbol &Sym = Ref->getSymbol();
397  if (!isThumbFunc(&Sym))
398    return false;
399
400  ThumbFuncs.insert(Symbol); // Cache it.
401  return true;
402}
403
404bool MCAssembler::isSymbolLinkerVisible(const MCSymbol &Symbol) const {
405  // Non-temporary labels should always be visible to the linker.
406  if (!Symbol.isTemporary())
407    return true;
408
409  // Absolute temporary labels are never visible.
410  if (!Symbol.isInSection())
411    return false;
412
413  // Otherwise, check if the section requires symbols even for temporary labels.
414  return getBackend().doesSectionRequireSymbols(Symbol.getSection());
415}
416
417const MCSymbolData *MCAssembler::getAtom(const MCSymbolData *SD) const {
418  // Linker visible symbols define atoms.
419  if (isSymbolLinkerVisible(SD->getSymbol()))
420    return SD;
421
422  // Absolute and undefined symbols have no defining atom.
423  if (!SD->getFragment())
424    return nullptr;
425
426  // Non-linker visible symbols in sections which can't be atomized have no
427  // defining atom.
428  if (!getBackend().isSectionAtomizable(
429        SD->getFragment()->getParent()->getSection()))
430    return nullptr;
431
432  // Otherwise, return the atom for the containing fragment.
433  return SD->getFragment()->getAtom();
434}
435
436bool MCAssembler::evaluateFixup(const MCAsmLayout &Layout,
437                                const MCFixup &Fixup, const MCFragment *DF,
438                                MCValue &Target, uint64_t &Value) const {
439  ++stats::evaluateFixup;
440
441  if (!Fixup.getValue()->EvaluateAsRelocatable(Target, &Layout))
442    getContext().FatalError(Fixup.getLoc(), "expected relocatable expression");
443
444  bool IsPCRel = Backend.getFixupKindInfo(
445    Fixup.getKind()).Flags & MCFixupKindInfo::FKF_IsPCRel;
446
447  bool IsResolved;
448  if (IsPCRel) {
449    if (Target.getSymB()) {
450      IsResolved = false;
451    } else if (!Target.getSymA()) {
452      IsResolved = false;
453    } else {
454      const MCSymbolRefExpr *A = Target.getSymA();
455      const MCSymbol &SA = A->getSymbol();
456      if (A->getKind() != MCSymbolRefExpr::VK_None ||
457          SA.AliasedSymbol().isUndefined()) {
458        IsResolved = false;
459      } else {
460        const MCSymbolData &DataA = getSymbolData(SA);
461        IsResolved =
462          getWriter().IsSymbolRefDifferenceFullyResolvedImpl(*this, DataA,
463                                                             *DF, false, true);
464      }
465    }
466  } else {
467    IsResolved = Target.isAbsolute();
468  }
469
470  Value = Target.getConstant();
471
472  if (const MCSymbolRefExpr *A = Target.getSymA()) {
473    const MCSymbol &Sym = A->getSymbol().AliasedSymbol();
474    if (Sym.isDefined())
475      Value += Layout.getSymbolOffset(&getSymbolData(Sym));
476  }
477  if (const MCSymbolRefExpr *B = Target.getSymB()) {
478    const MCSymbol &Sym = B->getSymbol().AliasedSymbol();
479    if (Sym.isDefined())
480      Value -= Layout.getSymbolOffset(&getSymbolData(Sym));
481  }
482
483
484  bool ShouldAlignPC = Backend.getFixupKindInfo(Fixup.getKind()).Flags &
485                         MCFixupKindInfo::FKF_IsAlignedDownTo32Bits;
486  assert((ShouldAlignPC ? IsPCRel : true) &&
487    "FKF_IsAlignedDownTo32Bits is only allowed on PC-relative fixups!");
488
489  if (IsPCRel) {
490    uint32_t Offset = Layout.getFragmentOffset(DF) + Fixup.getOffset();
491
492    // A number of ARM fixups in Thumb mode require that the effective PC
493    // address be determined as the 32-bit aligned version of the actual offset.
494    if (ShouldAlignPC) Offset &= ~0x3;
495    Value -= Offset;
496  }
497
498  // Let the backend adjust the fixup value if necessary, including whether
499  // we need a relocation.
500  Backend.processFixupValue(*this, Layout, Fixup, DF, Target, Value,
501                            IsResolved);
502
503  return IsResolved;
504}
505
506uint64_t MCAssembler::computeFragmentSize(const MCAsmLayout &Layout,
507                                          const MCFragment &F) const {
508  switch (F.getKind()) {
509  case MCFragment::FT_Data:
510  case MCFragment::FT_Relaxable:
511  case MCFragment::FT_CompactEncodedInst:
512    return cast<MCEncodedFragment>(F).getContents().size();
513  case MCFragment::FT_Fill:
514    return cast<MCFillFragment>(F).getSize();
515
516  case MCFragment::FT_LEB:
517    return cast<MCLEBFragment>(F).getContents().size();
518
519  case MCFragment::FT_Align: {
520    const MCAlignFragment &AF = cast<MCAlignFragment>(F);
521    unsigned Offset = Layout.getFragmentOffset(&AF);
522    unsigned Size = OffsetToAlignment(Offset, AF.getAlignment());
523    // If we are padding with nops, force the padding to be larger than the
524    // minimum nop size.
525    if (Size > 0 && AF.hasEmitNops()) {
526      while (Size % getBackend().getMinimumNopSize())
527        Size += AF.getAlignment();
528    }
529    if (Size > AF.getMaxBytesToEmit())
530      return 0;
531    return Size;
532  }
533
534  case MCFragment::FT_Org: {
535    const MCOrgFragment &OF = cast<MCOrgFragment>(F);
536    int64_t TargetLocation;
537    if (!OF.getOffset().EvaluateAsAbsolute(TargetLocation, Layout))
538      report_fatal_error("expected assembly-time absolute expression");
539
540    // FIXME: We need a way to communicate this error.
541    uint64_t FragmentOffset = Layout.getFragmentOffset(&OF);
542    int64_t Size = TargetLocation - FragmentOffset;
543    if (Size < 0 || Size >= 0x40000000)
544      report_fatal_error("invalid .org offset '" + Twine(TargetLocation) +
545                         "' (at offset '" + Twine(FragmentOffset) + "')");
546    return Size;
547  }
548
549  case MCFragment::FT_Dwarf:
550    return cast<MCDwarfLineAddrFragment>(F).getContents().size();
551  case MCFragment::FT_DwarfFrame:
552    return cast<MCDwarfCallFrameFragment>(F).getContents().size();
553  }
554
555  llvm_unreachable("invalid fragment kind");
556}
557
558void MCAsmLayout::layoutFragment(MCFragment *F) {
559  MCFragment *Prev = F->getPrevNode();
560
561  // We should never try to recompute something which is valid.
562  assert(!isFragmentValid(F) && "Attempt to recompute a valid fragment!");
563  // We should never try to compute the fragment layout if its predecessor
564  // isn't valid.
565  assert((!Prev || isFragmentValid(Prev)) &&
566         "Attempt to compute fragment before its predecessor!");
567
568  ++stats::FragmentLayouts;
569
570  // Compute fragment offset and size.
571  if (Prev)
572    F->Offset = Prev->Offset + getAssembler().computeFragmentSize(*this, *Prev);
573  else
574    F->Offset = 0;
575  LastValidFragment[F->getParent()] = F;
576
577  // If bundling is enabled and this fragment has instructions in it, it has to
578  // obey the bundling restrictions. With padding, we'll have:
579  //
580  //
581  //        BundlePadding
582  //             |||
583  // -------------------------------------
584  //   Prev  |##########|       F        |
585  // -------------------------------------
586  //                    ^
587  //                    |
588  //                    F->Offset
589  //
590  // The fragment's offset will point to after the padding, and its computed
591  // size won't include the padding.
592  //
593  if (Assembler.isBundlingEnabled() && F->hasInstructions()) {
594    assert(isa<MCEncodedFragment>(F) &&
595           "Only MCEncodedFragment implementations have instructions");
596    uint64_t FSize = Assembler.computeFragmentSize(*this, *F);
597
598    if (FSize > Assembler.getBundleAlignSize())
599      report_fatal_error("Fragment can't be larger than a bundle size");
600
601    uint64_t RequiredBundlePadding = computeBundlePadding(F, F->Offset, FSize);
602    if (RequiredBundlePadding > UINT8_MAX)
603      report_fatal_error("Padding cannot exceed 255 bytes");
604    F->setBundlePadding(static_cast<uint8_t>(RequiredBundlePadding));
605    F->Offset += RequiredBundlePadding;
606  }
607}
608
609/// \brief Write the contents of a fragment to the given object writer. Expects
610///        a MCEncodedFragment.
611static void writeFragmentContents(const MCFragment &F, MCObjectWriter *OW) {
612  const MCEncodedFragment &EF = cast<MCEncodedFragment>(F);
613  OW->WriteBytes(EF.getContents());
614}
615
616/// \brief Write the fragment \p F to the output file.
617static void writeFragment(const MCAssembler &Asm, const MCAsmLayout &Layout,
618                          const MCFragment &F) {
619  MCObjectWriter *OW = &Asm.getWriter();
620
621  // FIXME: Embed in fragments instead?
622  uint64_t FragmentSize = Asm.computeFragmentSize(Layout, F);
623
624  // Should NOP padding be written out before this fragment?
625  unsigned BundlePadding = F.getBundlePadding();
626  if (BundlePadding > 0) {
627    assert(Asm.isBundlingEnabled() &&
628           "Writing bundle padding with disabled bundling");
629    assert(F.hasInstructions() &&
630           "Writing bundle padding for a fragment without instructions");
631
632    unsigned TotalLength = BundlePadding + static_cast<unsigned>(FragmentSize);
633    if (F.alignToBundleEnd() && TotalLength > Asm.getBundleAlignSize()) {
634      // If the padding itself crosses a bundle boundary, it must be emitted
635      // in 2 pieces, since even nop instructions must not cross boundaries.
636      //             v--------------v   <- BundleAlignSize
637      //        v---------v             <- BundlePadding
638      // ----------------------------
639      // | Prev |####|####|    F    |
640      // ----------------------------
641      //        ^-------------------^   <- TotalLength
642      unsigned DistanceToBoundary = TotalLength - Asm.getBundleAlignSize();
643      if (!Asm.getBackend().writeNopData(DistanceToBoundary, OW))
644          report_fatal_error("unable to write NOP sequence of " +
645                             Twine(DistanceToBoundary) + " bytes");
646      BundlePadding -= DistanceToBoundary;
647    }
648    if (!Asm.getBackend().writeNopData(BundlePadding, OW))
649      report_fatal_error("unable to write NOP sequence of " +
650                         Twine(BundlePadding) + " bytes");
651  }
652
653  // This variable (and its dummy usage) is to participate in the assert at
654  // the end of the function.
655  uint64_t Start = OW->getStream().tell();
656  (void) Start;
657
658  ++stats::EmittedFragments;
659
660  switch (F.getKind()) {
661  case MCFragment::FT_Align: {
662    ++stats::EmittedAlignFragments;
663    const MCAlignFragment &AF = cast<MCAlignFragment>(F);
664    assert(AF.getValueSize() && "Invalid virtual align in concrete fragment!");
665
666    uint64_t Count = FragmentSize / AF.getValueSize();
667
668    // FIXME: This error shouldn't actually occur (the front end should emit
669    // multiple .align directives to enforce the semantics it wants), but is
670    // severe enough that we want to report it. How to handle this?
671    if (Count * AF.getValueSize() != FragmentSize)
672      report_fatal_error("undefined .align directive, value size '" +
673                        Twine(AF.getValueSize()) +
674                        "' is not a divisor of padding size '" +
675                        Twine(FragmentSize) + "'");
676
677    // See if we are aligning with nops, and if so do that first to try to fill
678    // the Count bytes.  Then if that did not fill any bytes or there are any
679    // bytes left to fill use the Value and ValueSize to fill the rest.
680    // If we are aligning with nops, ask that target to emit the right data.
681    if (AF.hasEmitNops()) {
682      if (!Asm.getBackend().writeNopData(Count, OW))
683        report_fatal_error("unable to write nop sequence of " +
684                          Twine(Count) + " bytes");
685      break;
686    }
687
688    // Otherwise, write out in multiples of the value size.
689    for (uint64_t i = 0; i != Count; ++i) {
690      switch (AF.getValueSize()) {
691      default: llvm_unreachable("Invalid size!");
692      case 1: OW->Write8 (uint8_t (AF.getValue())); break;
693      case 2: OW->Write16(uint16_t(AF.getValue())); break;
694      case 4: OW->Write32(uint32_t(AF.getValue())); break;
695      case 8: OW->Write64(uint64_t(AF.getValue())); break;
696      }
697    }
698    break;
699  }
700
701  case MCFragment::FT_Data:
702    ++stats::EmittedDataFragments;
703    writeFragmentContents(F, OW);
704    break;
705
706  case MCFragment::FT_Relaxable:
707    ++stats::EmittedRelaxableFragments;
708    writeFragmentContents(F, OW);
709    break;
710
711  case MCFragment::FT_CompactEncodedInst:
712    ++stats::EmittedCompactEncodedInstFragments;
713    writeFragmentContents(F, OW);
714    break;
715
716  case MCFragment::FT_Fill: {
717    ++stats::EmittedFillFragments;
718    const MCFillFragment &FF = cast<MCFillFragment>(F);
719
720    assert(FF.getValueSize() && "Invalid virtual align in concrete fragment!");
721
722    for (uint64_t i = 0, e = FF.getSize() / FF.getValueSize(); i != e; ++i) {
723      switch (FF.getValueSize()) {
724      default: llvm_unreachable("Invalid size!");
725      case 1: OW->Write8 (uint8_t (FF.getValue())); break;
726      case 2: OW->Write16(uint16_t(FF.getValue())); break;
727      case 4: OW->Write32(uint32_t(FF.getValue())); break;
728      case 8: OW->Write64(uint64_t(FF.getValue())); break;
729      }
730    }
731    break;
732  }
733
734  case MCFragment::FT_LEB: {
735    const MCLEBFragment &LF = cast<MCLEBFragment>(F);
736    OW->WriteBytes(LF.getContents().str());
737    break;
738  }
739
740  case MCFragment::FT_Org: {
741    ++stats::EmittedOrgFragments;
742    const MCOrgFragment &OF = cast<MCOrgFragment>(F);
743
744    for (uint64_t i = 0, e = FragmentSize; i != e; ++i)
745      OW->Write8(uint8_t(OF.getValue()));
746
747    break;
748  }
749
750  case MCFragment::FT_Dwarf: {
751    const MCDwarfLineAddrFragment &OF = cast<MCDwarfLineAddrFragment>(F);
752    OW->WriteBytes(OF.getContents().str());
753    break;
754  }
755  case MCFragment::FT_DwarfFrame: {
756    const MCDwarfCallFrameFragment &CF = cast<MCDwarfCallFrameFragment>(F);
757    OW->WriteBytes(CF.getContents().str());
758    break;
759  }
760  }
761
762  assert(OW->getStream().tell() - Start == FragmentSize &&
763         "The stream should advance by fragment size");
764}
765
766void MCAssembler::writeSectionData(const MCSectionData *SD,
767                                   const MCAsmLayout &Layout) const {
768  // Ignore virtual sections.
769  if (SD->getSection().isVirtualSection()) {
770    assert(Layout.getSectionFileSize(SD) == 0 && "Invalid size for section!");
771
772    // Check that contents are only things legal inside a virtual section.
773    for (MCSectionData::const_iterator it = SD->begin(),
774           ie = SD->end(); it != ie; ++it) {
775      switch (it->getKind()) {
776      default: llvm_unreachable("Invalid fragment in virtual section!");
777      case MCFragment::FT_Data: {
778        // Check that we aren't trying to write a non-zero contents (or fixups)
779        // into a virtual section. This is to support clients which use standard
780        // directives to fill the contents of virtual sections.
781        const MCDataFragment &DF = cast<MCDataFragment>(*it);
782        assert(DF.fixup_begin() == DF.fixup_end() &&
783               "Cannot have fixups in virtual section!");
784        for (unsigned i = 0, e = DF.getContents().size(); i != e; ++i)
785          assert(DF.getContents()[i] == 0 &&
786                 "Invalid data value for virtual section!");
787        break;
788      }
789      case MCFragment::FT_Align:
790        // Check that we aren't trying to write a non-zero value into a virtual
791        // section.
792        assert((cast<MCAlignFragment>(it)->getValueSize() == 0 ||
793                cast<MCAlignFragment>(it)->getValue() == 0) &&
794               "Invalid align in virtual section!");
795        break;
796      case MCFragment::FT_Fill:
797        assert((cast<MCFillFragment>(it)->getValueSize() == 0 ||
798                cast<MCFillFragment>(it)->getValue() == 0) &&
799               "Invalid fill in virtual section!");
800        break;
801      }
802    }
803
804    return;
805  }
806
807  uint64_t Start = getWriter().getStream().tell();
808  (void)Start;
809
810  for (MCSectionData::const_iterator it = SD->begin(), ie = SD->end();
811       it != ie; ++it)
812    writeFragment(*this, Layout, *it);
813
814  assert(getWriter().getStream().tell() - Start ==
815         Layout.getSectionAddressSize(SD));
816}
817
818std::pair<uint64_t, bool> MCAssembler::handleFixup(const MCAsmLayout &Layout,
819                                                   MCFragment &F,
820                                                   const MCFixup &Fixup) {
821  // Evaluate the fixup.
822  MCValue Target;
823  uint64_t FixedValue;
824  bool IsPCRel = Backend.getFixupKindInfo(Fixup.getKind()).Flags &
825                 MCFixupKindInfo::FKF_IsPCRel;
826  if (!evaluateFixup(Layout, Fixup, &F, Target, FixedValue)) {
827    // The fixup was unresolved, we need a relocation. Inform the object
828    // writer of the relocation, and give it an opportunity to adjust the
829    // fixup value if need be.
830    getWriter().RecordRelocation(*this, Layout, &F, Fixup, Target, IsPCRel,
831                                 FixedValue);
832  }
833  return std::make_pair(FixedValue, IsPCRel);
834}
835
836void MCAssembler::Finish() {
837  DEBUG_WITH_TYPE("mc-dump", {
838      llvm::errs() << "assembler backend - pre-layout\n--\n";
839      dump(); });
840
841  // Create the layout object.
842  MCAsmLayout Layout(*this);
843
844  // Create dummy fragments and assign section ordinals.
845  unsigned SectionIndex = 0;
846  for (MCAssembler::iterator it = begin(), ie = end(); it != ie; ++it) {
847    // Create dummy fragments to eliminate any empty sections, this simplifies
848    // layout.
849    if (it->getFragmentList().empty())
850      new MCDataFragment(it);
851
852    it->setOrdinal(SectionIndex++);
853  }
854
855  // Assign layout order indices to sections and fragments.
856  for (unsigned i = 0, e = Layout.getSectionOrder().size(); i != e; ++i) {
857    MCSectionData *SD = Layout.getSectionOrder()[i];
858    SD->setLayoutOrder(i);
859
860    unsigned FragmentIndex = 0;
861    for (MCSectionData::iterator iFrag = SD->begin(), iFragEnd = SD->end();
862         iFrag != iFragEnd; ++iFrag)
863      iFrag->setLayoutOrder(FragmentIndex++);
864  }
865
866  // Layout until everything fits.
867  while (layoutOnce(Layout))
868    continue;
869
870  DEBUG_WITH_TYPE("mc-dump", {
871      llvm::errs() << "assembler backend - post-relaxation\n--\n";
872      dump(); });
873
874  // Finalize the layout, including fragment lowering.
875  finishLayout(Layout);
876
877  DEBUG_WITH_TYPE("mc-dump", {
878      llvm::errs() << "assembler backend - final-layout\n--\n";
879      dump(); });
880
881  uint64_t StartOffset = OS.tell();
882
883  // Allow the object writer a chance to perform post-layout binding (for
884  // example, to set the index fields in the symbol data).
885  getWriter().ExecutePostLayoutBinding(*this, Layout);
886
887  // Evaluate and apply the fixups, generating relocation entries as necessary.
888  for (MCAssembler::iterator it = begin(), ie = end(); it != ie; ++it) {
889    for (MCSectionData::iterator it2 = it->begin(),
890           ie2 = it->end(); it2 != ie2; ++it2) {
891      MCEncodedFragmentWithFixups *F =
892        dyn_cast<MCEncodedFragmentWithFixups>(it2);
893      if (F) {
894        for (MCEncodedFragmentWithFixups::fixup_iterator it3 = F->fixup_begin(),
895             ie3 = F->fixup_end(); it3 != ie3; ++it3) {
896          MCFixup &Fixup = *it3;
897          uint64_t FixedValue;
898          bool IsPCRel;
899          std::tie(FixedValue, IsPCRel) = handleFixup(Layout, *F, Fixup);
900          getBackend().applyFixup(Fixup, F->getContents().data(),
901                                  F->getContents().size(), FixedValue, IsPCRel);
902        }
903      }
904    }
905  }
906
907  // Write the object file.
908  getWriter().WriteObject(*this, Layout);
909
910  stats::ObjectBytes += OS.tell() - StartOffset;
911}
912
913bool MCAssembler::fixupNeedsRelaxation(const MCFixup &Fixup,
914                                       const MCRelaxableFragment *DF,
915                                       const MCAsmLayout &Layout) const {
916  // If we cannot resolve the fixup value, it requires relaxation.
917  MCValue Target;
918  uint64_t Value;
919  if (!evaluateFixup(Layout, Fixup, DF, Target, Value))
920    return true;
921
922  return getBackend().fixupNeedsRelaxation(Fixup, Value, DF, Layout);
923}
924
925bool MCAssembler::fragmentNeedsRelaxation(const MCRelaxableFragment *F,
926                                          const MCAsmLayout &Layout) const {
927  // If this inst doesn't ever need relaxation, ignore it. This occurs when we
928  // are intentionally pushing out inst fragments, or because we relaxed a
929  // previous instruction to one that doesn't need relaxation.
930  if (!getBackend().mayNeedRelaxation(F->getInst()))
931    return false;
932
933  for (MCRelaxableFragment::const_fixup_iterator it = F->fixup_begin(),
934       ie = F->fixup_end(); it != ie; ++it)
935    if (fixupNeedsRelaxation(*it, F, Layout))
936      return true;
937
938  return false;
939}
940
941bool MCAssembler::relaxInstruction(MCAsmLayout &Layout,
942                                   MCRelaxableFragment &F) {
943  if (!fragmentNeedsRelaxation(&F, Layout))
944    return false;
945
946  ++stats::RelaxedInstructions;
947
948  // FIXME-PERF: We could immediately lower out instructions if we can tell
949  // they are fully resolved, to avoid retesting on later passes.
950
951  // Relax the fragment.
952
953  MCInst Relaxed;
954  getBackend().relaxInstruction(F.getInst(), Relaxed);
955
956  // Encode the new instruction.
957  //
958  // FIXME-PERF: If it matters, we could let the target do this. It can
959  // probably do so more efficiently in many cases.
960  SmallVector<MCFixup, 4> Fixups;
961  SmallString<256> Code;
962  raw_svector_ostream VecOS(Code);
963  getEmitter().EncodeInstruction(Relaxed, VecOS, Fixups, F.getSubtargetInfo());
964  VecOS.flush();
965
966  // Update the fragment.
967  F.setInst(Relaxed);
968  F.getContents() = Code;
969  F.getFixups() = Fixups;
970
971  return true;
972}
973
974bool MCAssembler::relaxLEB(MCAsmLayout &Layout, MCLEBFragment &LF) {
975  int64_t Value = 0;
976  uint64_t OldSize = LF.getContents().size();
977  bool IsAbs = LF.getValue().EvaluateAsAbsolute(Value, Layout);
978  (void)IsAbs;
979  assert(IsAbs);
980  SmallString<8> &Data = LF.getContents();
981  Data.clear();
982  raw_svector_ostream OSE(Data);
983  if (LF.isSigned())
984    encodeSLEB128(Value, OSE);
985  else
986    encodeULEB128(Value, OSE);
987  OSE.flush();
988  return OldSize != LF.getContents().size();
989}
990
991bool MCAssembler::relaxDwarfLineAddr(MCAsmLayout &Layout,
992                                     MCDwarfLineAddrFragment &DF) {
993  MCContext &Context = Layout.getAssembler().getContext();
994  int64_t AddrDelta = 0;
995  uint64_t OldSize = DF.getContents().size();
996  bool IsAbs = DF.getAddrDelta().EvaluateAsAbsolute(AddrDelta, Layout);
997  (void)IsAbs;
998  assert(IsAbs);
999  int64_t LineDelta;
1000  LineDelta = DF.getLineDelta();
1001  SmallString<8> &Data = DF.getContents();
1002  Data.clear();
1003  raw_svector_ostream OSE(Data);
1004  MCDwarfLineAddr::Encode(Context, LineDelta, AddrDelta, OSE);
1005  OSE.flush();
1006  return OldSize != Data.size();
1007}
1008
1009bool MCAssembler::relaxDwarfCallFrameFragment(MCAsmLayout &Layout,
1010                                              MCDwarfCallFrameFragment &DF) {
1011  MCContext &Context = Layout.getAssembler().getContext();
1012  int64_t AddrDelta = 0;
1013  uint64_t OldSize = DF.getContents().size();
1014  bool IsAbs = DF.getAddrDelta().EvaluateAsAbsolute(AddrDelta, Layout);
1015  (void)IsAbs;
1016  assert(IsAbs);
1017  SmallString<8> &Data = DF.getContents();
1018  Data.clear();
1019  raw_svector_ostream OSE(Data);
1020  MCDwarfFrameEmitter::EncodeAdvanceLoc(Context, AddrDelta, OSE);
1021  OSE.flush();
1022  return OldSize != Data.size();
1023}
1024
1025bool MCAssembler::layoutSectionOnce(MCAsmLayout &Layout, MCSectionData &SD) {
1026  // Holds the first fragment which needed relaxing during this layout. It will
1027  // remain NULL if none were relaxed.
1028  // When a fragment is relaxed, all the fragments following it should get
1029  // invalidated because their offset is going to change.
1030  MCFragment *FirstRelaxedFragment = nullptr;
1031
1032  // Attempt to relax all the fragments in the section.
1033  for (MCSectionData::iterator I = SD.begin(), IE = SD.end(); I != IE; ++I) {
1034    // Check if this is a fragment that needs relaxation.
1035    bool RelaxedFrag = false;
1036    switch(I->getKind()) {
1037    default:
1038      break;
1039    case MCFragment::FT_Relaxable:
1040      assert(!getRelaxAll() &&
1041             "Did not expect a MCRelaxableFragment in RelaxAll mode");
1042      RelaxedFrag = relaxInstruction(Layout, *cast<MCRelaxableFragment>(I));
1043      break;
1044    case MCFragment::FT_Dwarf:
1045      RelaxedFrag = relaxDwarfLineAddr(Layout,
1046                                       *cast<MCDwarfLineAddrFragment>(I));
1047      break;
1048    case MCFragment::FT_DwarfFrame:
1049      RelaxedFrag =
1050        relaxDwarfCallFrameFragment(Layout,
1051                                    *cast<MCDwarfCallFrameFragment>(I));
1052      break;
1053    case MCFragment::FT_LEB:
1054      RelaxedFrag = relaxLEB(Layout, *cast<MCLEBFragment>(I));
1055      break;
1056    }
1057    if (RelaxedFrag && !FirstRelaxedFragment)
1058      FirstRelaxedFragment = I;
1059  }
1060  if (FirstRelaxedFragment) {
1061    Layout.invalidateFragmentsFrom(FirstRelaxedFragment);
1062    return true;
1063  }
1064  return false;
1065}
1066
1067bool MCAssembler::layoutOnce(MCAsmLayout &Layout) {
1068  ++stats::RelaxationSteps;
1069
1070  bool WasRelaxed = false;
1071  for (iterator it = begin(), ie = end(); it != ie; ++it) {
1072    MCSectionData &SD = *it;
1073    while (layoutSectionOnce(Layout, SD))
1074      WasRelaxed = true;
1075  }
1076
1077  return WasRelaxed;
1078}
1079
1080void MCAssembler::finishLayout(MCAsmLayout &Layout) {
1081  // The layout is done. Mark every fragment as valid.
1082  for (unsigned int i = 0, n = Layout.getSectionOrder().size(); i != n; ++i) {
1083    Layout.getFragmentOffset(&*Layout.getSectionOrder()[i]->rbegin());
1084  }
1085}
1086
1087// Debugging methods
1088
1089namespace llvm {
1090
1091raw_ostream &operator<<(raw_ostream &OS, const MCFixup &AF) {
1092  OS << "<MCFixup" << " Offset:" << AF.getOffset()
1093     << " Value:" << *AF.getValue()
1094     << " Kind:" << AF.getKind() << ">";
1095  return OS;
1096}
1097
1098}
1099
1100#if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
1101void MCFragment::dump() {
1102  raw_ostream &OS = llvm::errs();
1103
1104  OS << "<";
1105  switch (getKind()) {
1106  case MCFragment::FT_Align: OS << "MCAlignFragment"; break;
1107  case MCFragment::FT_Data:  OS << "MCDataFragment"; break;
1108  case MCFragment::FT_CompactEncodedInst:
1109    OS << "MCCompactEncodedInstFragment"; break;
1110  case MCFragment::FT_Fill:  OS << "MCFillFragment"; break;
1111  case MCFragment::FT_Relaxable:  OS << "MCRelaxableFragment"; break;
1112  case MCFragment::FT_Org:   OS << "MCOrgFragment"; break;
1113  case MCFragment::FT_Dwarf: OS << "MCDwarfFragment"; break;
1114  case MCFragment::FT_DwarfFrame: OS << "MCDwarfCallFrameFragment"; break;
1115  case MCFragment::FT_LEB:   OS << "MCLEBFragment"; break;
1116  }
1117
1118  OS << "<MCFragment " << (void*) this << " LayoutOrder:" << LayoutOrder
1119     << " Offset:" << Offset
1120     << " HasInstructions:" << hasInstructions()
1121     << " BundlePadding:" << static_cast<unsigned>(getBundlePadding()) << ">";
1122
1123  switch (getKind()) {
1124  case MCFragment::FT_Align: {
1125    const MCAlignFragment *AF = cast<MCAlignFragment>(this);
1126    if (AF->hasEmitNops())
1127      OS << " (emit nops)";
1128    OS << "\n       ";
1129    OS << " Alignment:" << AF->getAlignment()
1130       << " Value:" << AF->getValue() << " ValueSize:" << AF->getValueSize()
1131       << " MaxBytesToEmit:" << AF->getMaxBytesToEmit() << ">";
1132    break;
1133  }
1134  case MCFragment::FT_Data:  {
1135    const MCDataFragment *DF = cast<MCDataFragment>(this);
1136    OS << "\n       ";
1137    OS << " Contents:[";
1138    const SmallVectorImpl<char> &Contents = DF->getContents();
1139    for (unsigned i = 0, e = Contents.size(); i != e; ++i) {
1140      if (i) OS << ",";
1141      OS << hexdigit((Contents[i] >> 4) & 0xF) << hexdigit(Contents[i] & 0xF);
1142    }
1143    OS << "] (" << Contents.size() << " bytes)";
1144
1145    if (DF->fixup_begin() != DF->fixup_end()) {
1146      OS << ",\n       ";
1147      OS << " Fixups:[";
1148      for (MCDataFragment::const_fixup_iterator it = DF->fixup_begin(),
1149             ie = DF->fixup_end(); it != ie; ++it) {
1150        if (it != DF->fixup_begin()) OS << ",\n                ";
1151        OS << *it;
1152      }
1153      OS << "]";
1154    }
1155    break;
1156  }
1157  case MCFragment::FT_CompactEncodedInst: {
1158    const MCCompactEncodedInstFragment *CEIF =
1159      cast<MCCompactEncodedInstFragment>(this);
1160    OS << "\n       ";
1161    OS << " Contents:[";
1162    const SmallVectorImpl<char> &Contents = CEIF->getContents();
1163    for (unsigned i = 0, e = Contents.size(); i != e; ++i) {
1164      if (i) OS << ",";
1165      OS << hexdigit((Contents[i] >> 4) & 0xF) << hexdigit(Contents[i] & 0xF);
1166    }
1167    OS << "] (" << Contents.size() << " bytes)";
1168    break;
1169  }
1170  case MCFragment::FT_Fill:  {
1171    const MCFillFragment *FF = cast<MCFillFragment>(this);
1172    OS << " Value:" << FF->getValue() << " ValueSize:" << FF->getValueSize()
1173       << " Size:" << FF->getSize();
1174    break;
1175  }
1176  case MCFragment::FT_Relaxable:  {
1177    const MCRelaxableFragment *F = cast<MCRelaxableFragment>(this);
1178    OS << "\n       ";
1179    OS << " Inst:";
1180    F->getInst().dump_pretty(OS);
1181    break;
1182  }
1183  case MCFragment::FT_Org:  {
1184    const MCOrgFragment *OF = cast<MCOrgFragment>(this);
1185    OS << "\n       ";
1186    OS << " Offset:" << OF->getOffset() << " Value:" << OF->getValue();
1187    break;
1188  }
1189  case MCFragment::FT_Dwarf:  {
1190    const MCDwarfLineAddrFragment *OF = cast<MCDwarfLineAddrFragment>(this);
1191    OS << "\n       ";
1192    OS << " AddrDelta:" << OF->getAddrDelta()
1193       << " LineDelta:" << OF->getLineDelta();
1194    break;
1195  }
1196  case MCFragment::FT_DwarfFrame:  {
1197    const MCDwarfCallFrameFragment *CF = cast<MCDwarfCallFrameFragment>(this);
1198    OS << "\n       ";
1199    OS << " AddrDelta:" << CF->getAddrDelta();
1200    break;
1201  }
1202  case MCFragment::FT_LEB: {
1203    const MCLEBFragment *LF = cast<MCLEBFragment>(this);
1204    OS << "\n       ";
1205    OS << " Value:" << LF->getValue() << " Signed:" << LF->isSigned();
1206    break;
1207  }
1208  }
1209  OS << ">";
1210}
1211
1212void MCSectionData::dump() {
1213  raw_ostream &OS = llvm::errs();
1214
1215  OS << "<MCSectionData";
1216  OS << " Alignment:" << getAlignment()
1217     << " Fragments:[\n      ";
1218  for (iterator it = begin(), ie = end(); it != ie; ++it) {
1219    if (it != begin()) OS << ",\n      ";
1220    it->dump();
1221  }
1222  OS << "]>";
1223}
1224
1225void MCSymbolData::dump() {
1226  raw_ostream &OS = llvm::errs();
1227
1228  OS << "<MCSymbolData Symbol:" << getSymbol()
1229     << " Fragment:" << getFragment() << " Offset:" << getOffset()
1230     << " Flags:" << getFlags() << " Index:" << getIndex();
1231  if (isCommon())
1232    OS << " (common, size:" << getCommonSize()
1233       << " align: " << getCommonAlignment() << ")";
1234  if (isExternal())
1235    OS << " (external)";
1236  if (isPrivateExtern())
1237    OS << " (private extern)";
1238  OS << ">";
1239}
1240
1241void MCAssembler::dump() {
1242  raw_ostream &OS = llvm::errs();
1243
1244  OS << "<MCAssembler\n";
1245  OS << "  Sections:[\n    ";
1246  for (iterator it = begin(), ie = end(); it != ie; ++it) {
1247    if (it != begin()) OS << ",\n    ";
1248    it->dump();
1249  }
1250  OS << "],\n";
1251  OS << "  Symbols:[";
1252
1253  for (symbol_iterator it = symbol_begin(), ie = symbol_end(); it != ie; ++it) {
1254    if (it != symbol_begin()) OS << ",\n           ";
1255    it->dump();
1256  }
1257  OS << "]>\n";
1258}
1259#endif
1260
1261// anchors for MC*Fragment vtables
1262void MCEncodedFragment::anchor() { }
1263void MCEncodedFragmentWithFixups::anchor() { }
1264void MCDataFragment::anchor() { }
1265void MCCompactEncodedInstFragment::anchor() { }
1266void MCRelaxableFragment::anchor() { }
1267void MCAlignFragment::anchor() { }
1268void MCFillFragment::anchor() { }
1269void MCOrgFragment::anchor() { }
1270void MCLEBFragment::anchor() { }
1271void MCDwarfLineAddrFragment::anchor() { }
1272void MCDwarfCallFrameFragment::anchor() { }
1273