Exemplo n.º 1
0
MCSection::iterator
MCSection::getSubsectionInsertionPoint(unsigned Subsection) {
  if (Subsection == 0 && SubsectionFragmentMap.empty())
    return end();

  SmallVectorImpl<std::pair<unsigned, MCFragment *>>::iterator MI =
      std::lower_bound(SubsectionFragmentMap.begin(),
                       SubsectionFragmentMap.end(),
                       std::make_pair(Subsection, (MCFragment *)nullptr));
  bool ExactMatch = false;
  if (MI != SubsectionFragmentMap.end()) {
    ExactMatch = MI->first == Subsection;
    if (ExactMatch)
      ++MI;
  }
  iterator IP;
  if (MI == SubsectionFragmentMap.end())
    IP = end();
  else
    IP = MI->second->getIterator();
  if (!ExactMatch && Subsection != 0) {
    // The GNU as documentation claims that subsections have an alignment of 4,
    // although this appears not to be the case.
    MCFragment *F = new MCDataFragment();
    SubsectionFragmentMap.insert(MI, std::make_pair(Subsection, F));
    getFragmentList().insert(IP, F);
    F->setParent(this);
  }

  return IP;
}
Exemplo n.º 2
0
void MCAssembler::writeFragmentPadding(const MCFragment &F, uint64_t FSize,
                                       MCObjectWriter *OW) const {
  // Should NOP padding be written out before this fragment?
  unsigned BundlePadding = F.getBundlePadding();
  if (BundlePadding > 0) {
    assert(isBundlingEnabled() &&
           "Writing bundle padding with disabled bundling");
    assert(F.hasInstructions() &&
           "Writing bundle padding for a fragment without instructions");

    unsigned TotalLength = BundlePadding + static_cast<unsigned>(FSize);
    if (F.alignToBundleEnd() && TotalLength > getBundleAlignSize()) {
      // If the padding itself crosses a bundle boundary, it must be emitted
      // in 2 pieces, since even nop instructions must not cross boundaries.
      //             v--------------v   <- BundleAlignSize
      //        v---------v             <- BundlePadding
      // ----------------------------
      // | Prev |####|####|    F    |
      // ----------------------------
      //        ^-------------------^   <- TotalLength
      unsigned DistanceToBoundary = TotalLength - getBundleAlignSize();
      if (!getBackend().writeNopData(DistanceToBoundary, OW))
          report_fatal_error("unable to write NOP sequence of " +
                             Twine(DistanceToBoundary) + " bytes");
      BundlePadding -= DistanceToBoundary;
    }
    if (!getBackend().writeNopData(BundlePadding, OW))
      report_fatal_error("unable to write NOP sequence of " +
                         Twine(BundlePadding) + " bytes");
  }
}
Exemplo n.º 3
0
bool MachObjectWriter::
IsSymbolRefDifferenceFullyResolvedImpl(const MCAssembler &Asm,
                                       const MCSymbolData &DataA,
                                       const MCFragment &FB,
                                       bool InSet,
                                       bool IsPCRel) const {
  if (InSet)
    return true;

  // The effective address is
  //     addr(atom(A)) + offset(A)
  //   - addr(atom(B)) - offset(B)
  // and the offsets are not relocatable, so the fixup is fully resolved when
  //  addr(atom(A)) - addr(atom(B)) == 0.
  const MCSymbolData *A_Base = 0, *B_Base = 0;

  const MCSymbol &SA = DataA.getSymbol().AliasedSymbol();
  const MCSection &SecA = SA.getSection();
  const MCSection &SecB = FB.getParent()->getSection();

  if (IsPCRel) {
    // The simple (Darwin, except on x86_64) way of dealing with this was to
    // assume that any reference to a temporary symbol *must* be a temporary
    // symbol in the same atom, unless the sections differ. Therefore, any PCrel
    // relocation to a temporary symbol (in the same section) is fully
    // resolved. This also works in conjunction with absolutized .set, which
    // requires the compiler to use .set to absolutize the differences between
    // symbols which the compiler knows to be assembly time constants, so we
    // don't need to worry about considering symbol differences fully resolved.

    if (!Asm.getBackend().hasReliableSymbolDifference()) {
      if (!SA.isTemporary() || !SA.isInSection() || &SecA != &SecB)
        return false;
      return true;
    }
  } else {
    if (!TargetObjectWriter->useAggressiveSymbolFolding())
      return false;
  }

  const MCFragment &FA = *Asm.getSymbolData(SA).getFragment();

  A_Base = FA.getAtom();
  if (!A_Base)
    return false;

  B_Base = FB.getAtom();
  if (!B_Base)
    return false;

  // If the atoms are the same, they are guaranteed to have the same address.
  if (A_Base == B_Base)
    return true;

  // Otherwise, we can't prove this is fully resolved.
  return false;
}
Exemplo n.º 4
0
void MCAsmLayout::EnsureValid(const MCFragment *F) const {
  MCSectionData &SD = *F->getParent();

  MCFragment *Cur = LastValidFragment[&SD];
  if (!Cur)
    Cur = &*SD.begin();
  else
    Cur = Cur->getNextNode();

  // Advance the layout position until the fragment is up-to-date.
  while (!isFragmentUpToDate(F)) {
    const_cast<MCAsmLayout*>(this)->LayoutFragment(Cur);
    Cur = Cur->getNextNode();
  }
}
Exemplo n.º 5
0
void MCAsmLayout::ensureValid(const MCFragment *F) const {
  MCSectionData &SD = *F->getParent();

  MCFragment *Cur = LastValidFragment[&SD];
  if (!Cur)
    Cur = &*SD.begin();
  else
    Cur = Cur->getNextNode();

  // Advance the layout position until the fragment is valid.
  while (!isFragmentValid(F)) {
    assert(Cur && "Layout bookkeeping error");
    const_cast<MCAsmLayout*>(this)->layoutFragment(Cur);
    Cur = Cur->getNextNode();
  }
}
Exemplo n.º 6
0
bool MCObjectWriter::isSymbolRefDifferenceFullyResolvedImpl(
    const MCAssembler &Asm, const MCSymbol &SymA, const MCFragment &FB,
    bool InSet, bool IsPCRel) const {
  const MCSection &SecA = SymA.getSection();
  const MCSection &SecB = *FB.getParent();
  // On ELF and COFF  A - B is absolute if A and B are in the same section.
  return &SecA == &SecB;
}
Exemplo n.º 7
0
void MCAsmLayout::EnsureValid(const MCFragment *F) const {
  // Advance the layout position until the fragment is up-to-date.
  while (!isFragmentUpToDate(F)) {
    // Advance to the next fragment.
    MCFragment *Cur = LastValidFragment;
    if (Cur)
      Cur = Cur->getNextNode();
    if (!Cur) {
      unsigned NextIndex = 0;
      if (LastValidFragment)
        NextIndex = LastValidFragment->getParent()->getLayoutOrder() + 1;
      Cur = SectionOrder[NextIndex]->begin();
    }

    const_cast<MCAsmLayout*>(this)->LayoutFragment(Cur);
  }
}
Exemplo n.º 8
0
void MCCodePadder::handleInstructionBegin(const MCInst &Inst) {
  if (!OS)
    return; // instruction was emitted outside a function

  assert(CurrHandledInstFragment == nullptr && "Can't start handling an "
                                               "instruction while still "
                                               "handling another instruction");

  bool InsertionPoint = instructionRequiresInsertionPoint(Inst);
  assert((!InsertionPoint ||
          OS->getCurrentFragment()->getKind() != MCFragment::FT_Align) &&
         "Cannot insert padding nops right after an alignment fragment as it "
         "will ruin the alignment");

  uint64_t PoliciesMask = MCPaddingFragment::PFK_None;
  if (ArePoliciesActive) {
    PoliciesMask = std::accumulate(
        CodePaddingPolicies.begin(), CodePaddingPolicies.end(),
        MCPaddingFragment::PFK_None,
        [&Inst](uint64_t Mask, const MCCodePaddingPolicy *Policy) -> uint64_t {
          return Policy->instructionRequiresPaddingFragment(Inst)
                     ? (Mask | Policy->getKindMask())
                     : Mask;
        });
  }
  MCFragment *CurrFragment = OS->getCurrentFragment();
  // CurrFragment can be a previously created MCPaddingFragment. If so, let's
  // update it with the information we have, such as the instruction that it
  // should point to.
  bool needToUpdateCurrFragment =
      CurrFragment != nullptr &&
      CurrFragment->getKind() == MCFragment::FT_Padding;
  if (InsertionPoint || PoliciesMask != MCPaddingFragment::PFK_None ||
      needToUpdateCurrFragment) {
    // temporarily holding the fragment as CurrHandledInstFragment, to be
    // updated after the instruction will be written
    CurrHandledInstFragment = OS->getOrCreatePaddingFragment();
    if (InsertionPoint)
      CurrHandledInstFragment->setAsInsertionPoint();
    CurrHandledInstFragment->setPaddingPoliciesMask(
        CurrHandledInstFragment->getPaddingPoliciesMask() | PoliciesMask);
  }
}
Exemplo n.º 9
0
uint64_t MCAssembler::computeFragmentSize(const MCAsmLayout &Layout,
                                          const MCFragment &F) const {
  switch (F.getKind()) {
  case MCFragment::FT_Data:
  case MCFragment::FT_Relaxable:
  case MCFragment::FT_CompactEncodedInst:
    return cast<MCEncodedFragment>(F).getContents().size();
  case MCFragment::FT_Fill:
    return cast<MCFillFragment>(F).getSize();

  case MCFragment::FT_LEB:
    return cast<MCLEBFragment>(F).getContents().size();

  case MCFragment::FT_Align: {
    const MCAlignFragment &AF = cast<MCAlignFragment>(F);
    unsigned Offset = Layout.getFragmentOffset(&AF);
    unsigned Size = OffsetToAlignment(Offset, AF.getAlignment());
    // If we are padding with nops, force the padding to be larger than the
    // minimum nop size.
    if (Size > 0 && AF.hasEmitNops()) {
      while (Size % getBackend().getMinimumNopSize())
        Size += AF.getAlignment();
    }
    if (Size > AF.getMaxBytesToEmit())
      return 0;
    return Size;
  }

  case MCFragment::FT_Org: {
    const MCOrgFragment &OF = cast<MCOrgFragment>(F);
    int64_t TargetLocation;
    if (!OF.getOffset().EvaluateAsAbsolute(TargetLocation, Layout))
      report_fatal_error("expected assembly-time absolute expression");

    // FIXME: We need a way to communicate this error.
    uint64_t FragmentOffset = Layout.getFragmentOffset(&OF);
    int64_t Size = TargetLocation - FragmentOffset;
    if (Size < 0 || Size >= 0x40000000)
      report_fatal_error("invalid .org offset '" + Twine(TargetLocation) +
                         "' (at offset '" + Twine(FragmentOffset) + "')");
    return Size;
  }

  case MCFragment::FT_Dwarf:
    return cast<MCDwarfLineAddrFragment>(F).getContents().size();
  case MCFragment::FT_DwarfFrame:
    return cast<MCDwarfCallFrameFragment>(F).getContents().size();
  }

  llvm_unreachable("invalid fragment kind");
}
Exemplo n.º 10
0
uint64_t MCAssembler::ComputeFragmentSize(MCAsmLayout &Layout,
                                          const MCFragment &F,
                                          uint64_t SectionAddress,
                                          uint64_t FragmentOffset) const {
  switch (F.getKind()) {
  case MCFragment::FT_Data:
    return cast<MCDataFragment>(F).getContents().size();
  case MCFragment::FT_Fill:
    return cast<MCFillFragment>(F).getSize();
  case MCFragment::FT_Inst:
    return cast<MCInstFragment>(F).getInstSize();

  case MCFragment::FT_Align: {
    const MCAlignFragment &AF = cast<MCAlignFragment>(F);

    assert((!AF.hasOnlyAlignAddress() || !AF.getNextNode()) &&
           "Invalid OnlyAlignAddress bit, not the last fragment!");

    uint64_t Size = OffsetToAlignment(SectionAddress + FragmentOffset,
                                      AF.getAlignment());

    // Honor MaxBytesToEmit.
    if (Size > AF.getMaxBytesToEmit())
      return 0;

    return Size;
  }

  case MCFragment::FT_Org: {
    const MCOrgFragment &OF = cast<MCOrgFragment>(F);

    // FIXME: We should compute this sooner, we don't want to recurse here, and
    // we would like to be more functional.
    int64_t TargetLocation;
    if (!OF.getOffset().EvaluateAsAbsolute(TargetLocation, &Layout))
      report_fatal_error("expected assembly-time absolute expression");

    // FIXME: We need a way to communicate this error.
    int64_t Offset = TargetLocation - FragmentOffset;
    if (Offset < 0)
      report_fatal_error("invalid .org offset '" + Twine(TargetLocation) +
                         "' (at offset '" + Twine(FragmentOffset) + "'");

    return Offset;
  }
  }

  assert(0 && "invalid fragment kind");
  return 0;
}
Exemplo n.º 11
0
MCPFRange &MCCodePadder::getJurisdiction(MCPaddingFragment *Fragment,
                                         MCAsmLayout &Layout) {
  auto JurisdictionLocation = FragmentToJurisdiction.find(Fragment);
  if (JurisdictionLocation != FragmentToJurisdiction.end())
    return JurisdictionLocation->second;

  MCPFRange Jurisdiction;

  // Forward scanning the fragments in this section, starting from the given
  // fragments, and adding relevant MCPaddingFragments to the Jurisdiction
  for (MCFragment *CurrFragment = Fragment; CurrFragment != nullptr;
       CurrFragment = CurrFragment->getNextNode()) {

    MCPaddingFragment *CurrPaddingFragment =
        dyn_cast<MCPaddingFragment>(CurrFragment);
    if (CurrPaddingFragment == nullptr)
      continue;

    if (CurrPaddingFragment != Fragment &&
        CurrPaddingFragment->isInsertionPoint())
      // Found next insertion point Fragment. From now on it's its jurisdiction.
      break;
    for (const auto *Policy : CodePaddingPolicies) {
      if (CurrPaddingFragment->hasPaddingPolicy(Policy->getKindMask())) {
        Jurisdiction.push_back(CurrPaddingFragment);
        break;
      }
    }
  }

  auto InsertionResult =
      FragmentToJurisdiction.insert(std::make_pair(Fragment, Jurisdiction));
  assert(InsertionResult.second &&
         "Insertion to FragmentToJurisdiction failed");
  return InsertionResult.first->second;
}
Exemplo n.º 12
0
bool MachObjectWriter::isSymbolRefDifferenceFullyResolvedImpl(
    const MCAssembler &Asm, const MCSymbol &SymA, const MCFragment &FB,
    bool InSet, bool IsPCRel) const {
  if (InSet)
    return true;

  // The effective address is
  //     addr(atom(A)) + offset(A)
  //   - addr(atom(B)) - offset(B)
  // and the offsets are not relocatable, so the fixup is fully resolved when
  //  addr(atom(A)) - addr(atom(B)) == 0.
  const MCSymbol &SA = findAliasedSymbol(SymA);
  const MCSection &SecA = SA.getSection();
  const MCSection &SecB = *FB.getParent();

  if (IsPCRel) {
    // The simple (Darwin, except on x86_64) way of dealing with this was to
    // assume that any reference to a temporary symbol *must* be a temporary
    // symbol in the same atom, unless the sections differ. Therefore, any PCrel
    // relocation to a temporary symbol (in the same section) is fully
    // resolved. This also works in conjunction with absolutized .set, which
    // requires the compiler to use .set to absolutize the differences between
    // symbols which the compiler knows to be assembly time constants, so we
    // don't need to worry about considering symbol differences fully resolved.
    //
    // If the file isn't using sub-sections-via-symbols, we can make the
    // same assumptions about any symbol that we normally make about
    // assembler locals.

    bool hasReliableSymbolDifference = isX86_64();
    if (!hasReliableSymbolDifference) {
      if (!SA.isInSection() || &SecA != &SecB ||
          (!SA.isTemporary() && FB.getAtom() != SA.getFragment()->getAtom() &&
           Asm.getSubsectionsViaSymbols()))
        return false;
      return true;
    }
    // For Darwin x86_64, there is one special case when the reference IsPCRel.
    // If the fragment with the reference does not have a base symbol but meets
    // the simple way of dealing with this, in that it is a temporary symbol in
    // the same atom then it is assumed to be fully resolved.  This is needed so
    // a relocation entry is not created and so the static linker does not
    // mess up the reference later.
    else if(!FB.getAtom() &&
            SA.isTemporary() && SA.isInSection() && &SecA == &SecB){
      return true;
    }
  }

  // If they are not in the same section, we can't compute the diff.
  if (&SecA != &SecB)
    return false;

  const MCFragment *FA = SA.getFragment();

  // Bail if the symbol has no fragment.
  if (!FA)
    return false;

  // If the atoms are the same, they are guaranteed to have the same address.
  if (FA->getAtom() == FB.getAtom())
    return true;

  // Otherwise, we can't prove this is fully resolved.
  return false;
}
Exemplo n.º 13
0
/// \brief Write the fragment \p F to the output file.
static void writeFragment(const MCAssembler &Asm, const MCAsmLayout &Layout,
                          const MCFragment &F) {
  MCObjectWriter *OW = &Asm.getWriter();

  // FIXME: Embed in fragments instead?
  uint64_t FragmentSize = Asm.computeFragmentSize(Layout, F);

  Asm.writeFragmentPadding(F, FragmentSize, OW);

  // This variable (and its dummy usage) is to participate in the assert at
  // the end of the function.
  uint64_t Start = OW->getStream().tell();
  (void) Start;

  ++stats::EmittedFragments;

  switch (F.getKind()) {
  case MCFragment::FT_Align: {
    ++stats::EmittedAlignFragments;
    const MCAlignFragment &AF = cast<MCAlignFragment>(F);
    assert(AF.getValueSize() && "Invalid virtual align in concrete fragment!");

    uint64_t Count = FragmentSize / AF.getValueSize();

    // FIXME: This error shouldn't actually occur (the front end should emit
    // multiple .align directives to enforce the semantics it wants), but is
    // severe enough that we want to report it. How to handle this?
    if (Count * AF.getValueSize() != FragmentSize)
      report_fatal_error("undefined .align directive, value size '" +
                        Twine(AF.getValueSize()) +
                        "' is not a divisor of padding size '" +
                        Twine(FragmentSize) + "'");

    // See if we are aligning with nops, and if so do that first to try to fill
    // the Count bytes.  Then if that did not fill any bytes or there are any
    // bytes left to fill use the Value and ValueSize to fill the rest.
    // If we are aligning with nops, ask that target to emit the right data.
    if (AF.hasEmitNops()) {
      if (!Asm.getBackend().writeNopData(Count, OW))
        report_fatal_error("unable to write nop sequence of " +
                          Twine(Count) + " bytes");
      break;
    }

    // Otherwise, write out in multiples of the value size.
    for (uint64_t i = 0; i != Count; ++i) {
      switch (AF.getValueSize()) {
      default: llvm_unreachable("Invalid size!");
      case 1: OW->write8 (uint8_t (AF.getValue())); break;
      case 2: OW->write16(uint16_t(AF.getValue())); break;
      case 4: OW->write32(uint32_t(AF.getValue())); break;
      case 8: OW->write64(uint64_t(AF.getValue())); break;
      }
    }
    break;
  }

  case MCFragment::FT_Data: 
    ++stats::EmittedDataFragments;
    OW->writeBytes(cast<MCDataFragment>(F).getContents());
    break;

  case MCFragment::FT_Relaxable:
    ++stats::EmittedRelaxableFragments;
    OW->writeBytes(cast<MCRelaxableFragment>(F).getContents());
    break;

  case MCFragment::FT_CompactEncodedInst:
    ++stats::EmittedCompactEncodedInstFragments;
    OW->writeBytes(cast<MCCompactEncodedInstFragment>(F).getContents());
    break;

  case MCFragment::FT_Fill: {
    ++stats::EmittedFillFragments;
    const MCFillFragment &FF = cast<MCFillFragment>(F);

    assert(FF.getValueSize() && "Invalid virtual align in concrete fragment!");

    for (uint64_t i = 0, e = FF.getSize() / FF.getValueSize(); i != e; ++i) {
      switch (FF.getValueSize()) {
      default: llvm_unreachable("Invalid size!");
      case 1: OW->write8 (uint8_t (FF.getValue())); break;
      case 2: OW->write16(uint16_t(FF.getValue())); break;
      case 4: OW->write32(uint32_t(FF.getValue())); break;
      case 8: OW->write64(uint64_t(FF.getValue())); break;
      }
    }
    break;
  }

  case MCFragment::FT_LEB: {
    const MCLEBFragment &LF = cast<MCLEBFragment>(F);
    OW->writeBytes(LF.getContents());
    break;
  }

  case MCFragment::FT_SafeSEH: {
    const MCSafeSEHFragment &SF = cast<MCSafeSEHFragment>(F);
    OW->write32(SF.getSymbol()->getIndex());
    break;
  }

  case MCFragment::FT_Org: {
    ++stats::EmittedOrgFragments;
    const MCOrgFragment &OF = cast<MCOrgFragment>(F);

    for (uint64_t i = 0, e = FragmentSize; i != e; ++i)
      OW->write8(uint8_t(OF.getValue()));

    break;
  }

  case MCFragment::FT_Dwarf: {
    const MCDwarfLineAddrFragment &OF = cast<MCDwarfLineAddrFragment>(F);
    OW->writeBytes(OF.getContents());
    break;
  }
  case MCFragment::FT_DwarfFrame: {
    const MCDwarfCallFrameFragment &CF = cast<MCDwarfCallFrameFragment>(F);
    OW->writeBytes(CF.getContents());
    break;
  }
  case MCFragment::FT_Dummy:
    llvm_unreachable("Should not have been added");
  }

  assert(OW->getStream().tell() - Start == FragmentSize &&
         "The stream should advance by fragment size");
}
Exemplo n.º 14
0
/// \brief Write the fragment \p F to the output file.
static void writeFragment(const MCAssembler &Asm, const MCAsmLayout &Layout,
                          const MCFragment &F) {
  MCObjectWriter *OW = &Asm.getWriter();

  // FIXME: Embed in fragments instead?
  uint64_t FragmentSize = Asm.computeFragmentSize(Layout, F);

  // Should NOP padding be written out before this fragment?
  unsigned BundlePadding = F.getBundlePadding();
  if (BundlePadding > 0) {
    assert(Asm.isBundlingEnabled() &&
           "Writing bundle padding with disabled bundling");
    assert(F.hasInstructions() &&
           "Writing bundle padding for a fragment without instructions");

    unsigned TotalLength = BundlePadding + static_cast<unsigned>(FragmentSize);
    if (F.alignToBundleEnd() && TotalLength > Asm.getBundleAlignSize()) {
      // If the padding itself crosses a bundle boundary, it must be emitted
      // in 2 pieces, since even nop instructions must not cross boundaries.
      //             v--------------v   <- BundleAlignSize
      //        v---------v             <- BundlePadding
      // ----------------------------
      // | Prev |####|####|    F    |
      // ----------------------------
      //        ^-------------------^   <- TotalLength
      unsigned DistanceToBoundary = TotalLength - Asm.getBundleAlignSize();
      if (!Asm.getBackend().writeNopData(DistanceToBoundary, OW))
          report_fatal_error("unable to write NOP sequence of " +
                             Twine(DistanceToBoundary) + " bytes");
      BundlePadding -= DistanceToBoundary;
    }
    if (!Asm.getBackend().writeNopData(BundlePadding, OW))
      report_fatal_error("unable to write NOP sequence of " +
                         Twine(BundlePadding) + " bytes");
  }

  // This variable (and its dummy usage) is to participate in the assert at
  // the end of the function.
  uint64_t Start = OW->getStream().tell();
  (void) Start;

  ++stats::EmittedFragments;

  switch (F.getKind()) {
  case MCFragment::FT_Align: {
    ++stats::EmittedAlignFragments;
    const MCAlignFragment &AF = cast<MCAlignFragment>(F);
    assert(AF.getValueSize() && "Invalid virtual align in concrete fragment!");

    uint64_t Count = FragmentSize / AF.getValueSize();

    // FIXME: This error shouldn't actually occur (the front end should emit
    // multiple .align directives to enforce the semantics it wants), but is
    // severe enough that we want to report it. How to handle this?
    if (Count * AF.getValueSize() != FragmentSize)
      report_fatal_error("undefined .align directive, value size '" +
                        Twine(AF.getValueSize()) +
                        "' is not a divisor of padding size '" +
                        Twine(FragmentSize) + "'");

    // See if we are aligning with nops, and if so do that first to try to fill
    // the Count bytes.  Then if that did not fill any bytes or there are any
    // bytes left to fill use the Value and ValueSize to fill the rest.
    // If we are aligning with nops, ask that target to emit the right data.
    if (AF.hasEmitNops()) {
      if (!Asm.getBackend().writeNopData(Count, OW))
        report_fatal_error("unable to write nop sequence of " +
                          Twine(Count) + " bytes");
      break;
    }

    // Otherwise, write out in multiples of the value size.
    for (uint64_t i = 0; i != Count; ++i) {
      switch (AF.getValueSize()) {
      default: llvm_unreachable("Invalid size!");
      case 1: OW->Write8 (uint8_t (AF.getValue())); break;
      case 2: OW->Write16(uint16_t(AF.getValue())); break;
      case 4: OW->Write32(uint32_t(AF.getValue())); break;
      case 8: OW->Write64(uint64_t(AF.getValue())); break;
      }
    }
    break;
  }

  case MCFragment::FT_Data: 
    ++stats::EmittedDataFragments;
    writeFragmentContents(F, OW);
    break;

  case MCFragment::FT_Relaxable:
    ++stats::EmittedRelaxableFragments;
    writeFragmentContents(F, OW);
    break;

  case MCFragment::FT_CompactEncodedInst:
    ++stats::EmittedCompactEncodedInstFragments;
    writeFragmentContents(F, OW);
    break;

  case MCFragment::FT_Fill: {
    ++stats::EmittedFillFragments;
    const MCFillFragment &FF = cast<MCFillFragment>(F);

    assert(FF.getValueSize() && "Invalid virtual align in concrete fragment!");

    for (uint64_t i = 0, e = FF.getSize() / FF.getValueSize(); i != e; ++i) {
      switch (FF.getValueSize()) {
      default: llvm_unreachable("Invalid size!");
      case 1: OW->Write8 (uint8_t (FF.getValue())); break;
      case 2: OW->Write16(uint16_t(FF.getValue())); break;
      case 4: OW->Write32(uint32_t(FF.getValue())); break;
      case 8: OW->Write64(uint64_t(FF.getValue())); break;
      }
    }
    break;
  }

  case MCFragment::FT_LEB: {
    const MCLEBFragment &LF = cast<MCLEBFragment>(F);
    OW->WriteBytes(LF.getContents().str());
    break;
  }

  case MCFragment::FT_Org: {
    ++stats::EmittedOrgFragments;
    const MCOrgFragment &OF = cast<MCOrgFragment>(F);

    for (uint64_t i = 0, e = FragmentSize; i != e; ++i)
      OW->Write8(uint8_t(OF.getValue()));

    break;
  }

  case MCFragment::FT_Dwarf: {
    const MCDwarfLineAddrFragment &OF = cast<MCDwarfLineAddrFragment>(F);
    OW->WriteBytes(OF.getContents().str());
    break;
  }
  case MCFragment::FT_DwarfFrame: {
    const MCDwarfCallFrameFragment &CF = cast<MCDwarfCallFrameFragment>(F);
    OW->WriteBytes(CF.getContents().str());
    break;
  }
  }

  assert(OW->getStream().tell() - Start == FragmentSize &&
         "The stream should advance by fragment size");
}
Exemplo n.º 15
0
/// WriteFragmentData - Write the \p F data to the output file.
static void WriteFragmentData(const MCAssembler &Asm, const MCAsmLayout &Layout,
                              const MCFragment &F) {
  MCObjectWriter *OW = &Asm.getWriter();
  uint64_t Start = OW->getStream().tell();
  (void) Start;

  ++stats::EmittedFragments;

  // FIXME: Embed in fragments instead?
  uint64_t FragmentSize = Asm.computeFragmentSize(Layout, F);
  switch (F.getKind()) {
  case MCFragment::FT_Align: {
    MCAlignFragment &AF = cast<MCAlignFragment>(F);
    uint64_t Count = FragmentSize / AF.getValueSize();

    assert(AF.getValueSize() && "Invalid virtual align in concrete fragment!");

    // FIXME: This error shouldn't actually occur (the front end should emit
    // multiple .align directives to enforce the semantics it wants), but is
    // severe enough that we want to report it. How to handle this?
    if (Count * AF.getValueSize() != FragmentSize)
      report_fatal_error("undefined .align directive, value size '" +
                        Twine(AF.getValueSize()) +
                        "' is not a divisor of padding size '" +
                        Twine(FragmentSize) + "'");

    // See if we are aligning with nops, and if so do that first to try to fill
    // the Count bytes.  Then if that did not fill any bytes or there are any
    // bytes left to fill use the Value and ValueSize to fill the rest.
    // If we are aligning with nops, ask that target to emit the right data.
    if (AF.hasEmitNops()) {
      if (!Asm.getBackend().writeNopData(Count, OW))
        report_fatal_error("unable to write nop sequence of " +
                          Twine(Count) + " bytes");
      break;
    }

    // Otherwise, write out in multiples of the value size.
    for (uint64_t i = 0; i != Count; ++i) {
      switch (AF.getValueSize()) {
      default: llvm_unreachable("Invalid size!");
      case 1: OW->Write8 (uint8_t (AF.getValue())); break;
      case 2: OW->Write16(uint16_t(AF.getValue())); break;
      case 4: OW->Write32(uint32_t(AF.getValue())); break;
      case 8: OW->Write64(uint64_t(AF.getValue())); break;
      }
    }
    break;
  }

  case MCFragment::FT_Data: {
    MCDataFragment &DF = cast<MCDataFragment>(F);
    assert(FragmentSize == DF.getContents().size() && "Invalid size!");
    OW->WriteBytes(DF.getContents().str());
    break;
  }

  case MCFragment::FT_Fill: {
    MCFillFragment &FF = cast<MCFillFragment>(F);

    assert(FF.getValueSize() && "Invalid virtual align in concrete fragment!");

    for (uint64_t i = 0, e = FF.getSize() / FF.getValueSize(); i != e; ++i) {
      switch (FF.getValueSize()) {
      default: llvm_unreachable("Invalid size!");
      case 1: OW->Write8 (uint8_t (FF.getValue())); break;
      case 2: OW->Write16(uint16_t(FF.getValue())); break;
      case 4: OW->Write32(uint32_t(FF.getValue())); break;
      case 8: OW->Write64(uint64_t(FF.getValue())); break;
      }
    }
    break;
  }

  case MCFragment::FT_Inst: {
    MCInstFragment &IF = cast<MCInstFragment>(F);
    OW->WriteBytes(StringRef(IF.getCode().begin(), IF.getCode().size()));
    break;
  }

  case MCFragment::FT_LEB: {
    MCLEBFragment &LF = cast<MCLEBFragment>(F);
    OW->WriteBytes(LF.getContents().str());
    break;
  }

  case MCFragment::FT_Org: {
    MCOrgFragment &OF = cast<MCOrgFragment>(F);

    for (uint64_t i = 0, e = FragmentSize; i != e; ++i)
      OW->Write8(uint8_t(OF.getValue()));

    break;
  }

  case MCFragment::FT_Dwarf: {
    const MCDwarfLineAddrFragment &OF = cast<MCDwarfLineAddrFragment>(F);
    OW->WriteBytes(OF.getContents().str());
    break;
  }
  case MCFragment::FT_DwarfFrame: {
    const MCDwarfCallFrameFragment &CF = cast<MCDwarfCallFrameFragment>(F);
    OW->WriteBytes(CF.getContents().str());
    break;
  }
  }

  assert(OW->getStream().tell() - Start == FragmentSize);
}
Exemplo n.º 16
0
uint64_t MCAssembler::computeFragmentSize(const MCAsmLayout &Layout,
                                          const MCFragment &F) const {
  switch (F.getKind()) {
  case MCFragment::FT_Data:
    return cast<MCDataFragment>(F).getContents().size();
  case MCFragment::FT_Relaxable:
    return cast<MCRelaxableFragment>(F).getContents().size();
  case MCFragment::FT_CompactEncodedInst:
    return cast<MCCompactEncodedInstFragment>(F).getContents().size();
  case MCFragment::FT_Fill:
    return cast<MCFillFragment>(F).getSize();

  case MCFragment::FT_LEB:
    return cast<MCLEBFragment>(F).getContents().size();

  case MCFragment::FT_SafeSEH:
    return 4;

  case MCFragment::FT_Align: {
    const MCAlignFragment &AF = cast<MCAlignFragment>(F);
    unsigned Offset = Layout.getFragmentOffset(&AF);
    unsigned Size = OffsetToAlignment(Offset, AF.getAlignment());
    // If we are padding with nops, force the padding to be larger than the
    // minimum nop size.
    if (Size > 0 && AF.hasEmitNops()) {
      while (Size % getBackend().getMinimumNopSize())
        Size += AF.getAlignment();
    }
    if (Size > AF.getMaxBytesToEmit())
      return 0;
    return Size;
  }

  case MCFragment::FT_Org: {
    const MCOrgFragment &OF = cast<MCOrgFragment>(F);
    MCValue Value;
    if (!OF.getOffset().evaluateAsValue(Value, Layout)) {
      getContext().reportError(OF.getLoc(),
                               "expected assembly-time absolute expression");
        return 0;
    }

    uint64_t FragmentOffset = Layout.getFragmentOffset(&OF);
    int64_t TargetLocation = Value.getConstant();
    if (const MCSymbolRefExpr *A = Value.getSymA()) {
      uint64_t Val;
      if (!Layout.getSymbolOffset(A->getSymbol(), Val)) {
        getContext().reportError(OF.getLoc(), "expected absolute expression");
        return 0;
      }
      TargetLocation += Val;
    }
    int64_t Size = TargetLocation - FragmentOffset;
    if (Size < 0 || Size >= 0x40000000) {
      getContext().reportError(
          OF.getLoc(), "invalid .org offset '" + Twine(TargetLocation) +
                           "' (at offset '" + Twine(FragmentOffset) + "')");
      return 0;
    }
    return Size;
  }

  case MCFragment::FT_Dwarf:
    return cast<MCDwarfLineAddrFragment>(F).getContents().size();
  case MCFragment::FT_DwarfFrame:
    return cast<MCDwarfCallFrameFragment>(F).getContents().size();
  case MCFragment::FT_CVInlineLines:
    return cast<MCCVInlineLineTableFragment>(F).getContents().size();
  case MCFragment::FT_CVDefRange:
    return cast<MCCVDefRangeFragment>(F).getContents().size();
  case MCFragment::FT_Dummy:
    llvm_unreachable("Should not have been added");
  }

  llvm_unreachable("invalid fragment kind");
}