Exemplo n.º 1
0
const MCSymbol *MCAsmLayout::getBaseSymbol(const MCSymbol &Symbol) const {
  if (!Symbol.isVariable())
    return &Symbol;

  const MCExpr *Expr = Symbol.getVariableValue();
  MCValue Value;
  if (!Expr->evaluateAsValue(Value, *this))
    llvm_unreachable("Invalid Expression");

  const MCSymbolRefExpr *RefB = Value.getSymB();
  if (RefB)
    Assembler.getContext().reportFatalError(
        SMLoc(), Twine("symbol '") + RefB->getSymbol().getName() +
                     "' could not be evaluated in a subtraction expression");

  const MCSymbolRefExpr *A = Value.getSymA();
  if (!A)
    return nullptr;

  const MCSymbol &ASym = A->getSymbol();
  const MCAssembler &Asm = getAssembler();
  if (ASym.isCommon()) {
    // FIXME: we should probably add a SMLoc to MCExpr.
    Asm.getContext().reportFatalError(SMLoc(),
                                "Common symbol " + ASym.getName() +
                                    " cannot be used in assignment expr");
  }

  return &ASym;
}
Exemplo n.º 2
0
void AMDGPUAsmBackend::processFixupValue(const MCAssembler &Asm,
                                         const MCAsmLayout &Layout,
                                         const MCFixup &Fixup, const MCFragment *DF,
                                         const MCValue &Target, uint64_t &Value,
                                         bool &IsResolved) {
  MCValue Res;

  // When we have complex expressions like: BB0_1 + (BB0_2 - 4), which are
  // used for long branches, this function will be called with
  // IsResolved = false and Value set to some pre-computed value.  In
  // the example above, the value would be:
  // (BB0_1 + (BB0_2 - 4)) - CurrentOffsetFromStartOfFunction.
  // This is not what we want.  We just want the expression computation
  // only.  The reason the MC layer subtracts the current offset from the
  // expression is because the fixup is of kind FK_PCRel_4.
  // For these scenarios, evaluateAsValue gives us the computation that we
  // want.
  if (!IsResolved && Fixup.getValue()->evaluateAsValue(Res, Layout) &&
      Res.isAbsolute()) {
    Value = Res.getConstant();
    IsResolved = true;

  }
  if (IsResolved)
    Value = adjustFixupValue(Fixup, Value, &Asm.getContext());
}
bool WinCOFFObjectWriter::IsFixupFullyResolved(const MCAssembler &Asm,
                                               const MCValue Target,
                                               bool IsPCRel,
                                               const MCFragment *DF) const {
  // If this is a PCrel relocation, find the section this fixup value is
  // relative to.
  const MCSection *BaseSection = 0;
  if (IsPCRel) {
    BaseSection = &DF->getParent()->getSection();
    assert(BaseSection);
  }

  const MCSection *SectionA = 0;
  const MCSymbol *SymbolA = 0;
  if (const MCSymbolRefExpr *A = Target.getSymA()) {
    SymbolA = &A->getSymbol();
    SectionA = &SymbolA->getSection();
  }

  const MCSection *SectionB = 0;
  if (const MCSymbolRefExpr *B = Target.getSymB()) {
    SectionB = &B->getSymbol().getSection();
  }

  if (!BaseSection)
    return SectionA == SectionB;

  return !SectionB && BaseSection == SectionA;
}
Exemplo n.º 4
0
const MCFixup *RISCVMCExpr::getPCRelHiFixup() const {
  MCValue AUIPCLoc;
  if (!getSubExpr()->evaluateAsRelocatable(AUIPCLoc, nullptr, nullptr))
    return nullptr;

  const MCSymbolRefExpr *AUIPCSRE = AUIPCLoc.getSymA();
  if (!AUIPCSRE)
    return nullptr;

  const auto *DF =
      dyn_cast_or_null<MCDataFragment>(AUIPCSRE->findAssociatedFragment());
  if (!DF)
    return nullptr;

  const MCSymbol *AUIPCSymbol = &AUIPCSRE->getSymbol();
  for (const MCFixup &F : DF->getFixups()) {
    if (F.getOffset() != AUIPCSymbol->getOffset())
      continue;

    switch ((unsigned)F.getKind()) {
    default:
      continue;
    case RISCV::fixup_riscv_pcrel_hi20:
      return &F;
    }
  }

  return nullptr;
}
Exemplo n.º 5
0
static bool getSymbolOffsetImpl(const MCAsmLayout &Layout, const MCSymbol &S,
                                bool ReportError, uint64_t &Val) {
  if (!S.isVariable())
    return getLabelOffset(Layout, S, ReportError, Val);

  // If SD is a variable, evaluate it.
  MCValue Target;
  if (!S.getVariableValue()->evaluateAsValue(Target, Layout))
    report_fatal_error("unable to evaluate offset for variable '" +
                       S.getName() + "'");

  uint64_t Offset = Target.getConstant();

  const MCSymbolRefExpr *A = Target.getSymA();
  if (A) {
    uint64_t ValA;
    if (!getLabelOffset(Layout, A->getSymbol(), ReportError, ValA))
      return false;
    Offset += ValA;
  }

  const MCSymbolRefExpr *B = Target.getSymB();
  if (B) {
    uint64_t ValB;
    if (!getLabelOffset(Layout, B->getSymbol(), ReportError, ValB))
      return false;
    Offset -= ValB;
  }

  Val = Offset;
  return true;
}
Exemplo n.º 6
0
bool MCAssembler::isThumbFunc(const MCSymbol *Symbol) const {
  if (ThumbFuncs.count(Symbol))
    return true;

  if (!Symbol->isVariable())
    return false;

  const MCExpr *Expr = Symbol->getVariableValue();

  MCValue V;
  if (!Expr->evaluateAsRelocatable(V, nullptr, nullptr))
    return false;

  if (V.getSymB() || V.getRefKind() != MCSymbolRefExpr::VK_None)
    return false;

  const MCSymbolRefExpr *Ref = V.getSymA();
  if (!Ref)
    return false;

  if (Ref->getKind() != MCSymbolRefExpr::VK_None)
    return false;

  const MCSymbol &Sym = Ref->getSymbol();
  if (!isThumbFunc(&Sym))
    return false;

  ThumbFuncs.insert(Symbol); // Cache it.
  return true;
}
unsigned X86WinCOFFObjectWriter::getRelocType(const MCValue &Target,
                                              const MCFixup &Fixup,
                                              bool IsCrossSection,
                                              const MCAsmBackend &MAB) const {
  unsigned FixupKind = IsCrossSection ? FK_PCRel_4 : Fixup.getKind();

  MCSymbolRefExpr::VariantKind Modifier = Target.isAbsolute() ?
    MCSymbolRefExpr::VK_None : Target.getSymA()->getKind();

  if (getMachine() == COFF::IMAGE_FILE_MACHINE_AMD64) {
    switch (FixupKind) {
    case FK_PCRel_4:
    case X86::reloc_riprel_4byte:
    case X86::reloc_riprel_4byte_movq_load:
    case X86::reloc_riprel_4byte_relax:
    case X86::reloc_riprel_4byte_relax_rex:
      return COFF::IMAGE_REL_AMD64_REL32;
    case FK_Data_4:
    case X86::reloc_signed_4byte:
    case X86::reloc_signed_4byte_relax:
      if (Modifier == MCSymbolRefExpr::VK_COFF_IMGREL32)
        return COFF::IMAGE_REL_AMD64_ADDR32NB;
      if (Modifier == MCSymbolRefExpr::VK_SECREL)
        return COFF::IMAGE_REL_AMD64_SECREL;
      return COFF::IMAGE_REL_AMD64_ADDR32;
    case FK_Data_8:
      return COFF::IMAGE_REL_AMD64_ADDR64;
    case FK_SecRel_2:
      return COFF::IMAGE_REL_AMD64_SECTION;
    case FK_SecRel_4:
      return COFF::IMAGE_REL_AMD64_SECREL;
    default:
      llvm_unreachable("unsupported relocation type");
    }
  } else if (getMachine() == COFF::IMAGE_FILE_MACHINE_I386) {
    switch (FixupKind) {
    case FK_PCRel_4:
    case X86::reloc_riprel_4byte:
    case X86::reloc_riprel_4byte_movq_load:
      return COFF::IMAGE_REL_I386_REL32;
    case FK_Data_4:
    case X86::reloc_signed_4byte:
    case X86::reloc_signed_4byte_relax:
      if (Modifier == MCSymbolRefExpr::VK_COFF_IMGREL32)
        return COFF::IMAGE_REL_I386_DIR32NB;
      if (Modifier == MCSymbolRefExpr::VK_SECREL)
        return COFF::IMAGE_REL_AMD64_SECREL;
      return COFF::IMAGE_REL_I386_DIR32;
    case FK_SecRel_2:
      return COFF::IMAGE_REL_I386_SECTION;
    case FK_SecRel_4:
      return COFF::IMAGE_REL_I386_SECREL;
    default:
      llvm_unreachable("unsupported relocation type");
    }
  } else
    llvm_unreachable("Unsupported COFF machine type.");
}
Exemplo n.º 8
0
/// NOTE: It is really important to have both the Asm and Layout arguments.
/// They might look redundant, but this function can be used before layout
/// is done (see the object streamer for example) and having the Asm argument
/// lets us avoid relaxations early.
static bool EvaluateSymbolicAdd(const MCAssembler *Asm,
                                const MCAsmLayout *Layout,
                                const SectionAddrMap *Addrs,
                                bool InSet,
                                const MCValue &LHS,const MCSymbolRefExpr *RHS_A,
                                const MCSymbolRefExpr *RHS_B, int64_t RHS_Cst,
                                MCValue &Res) {
  // FIXME: This routine (and other evaluation parts) are *incredibly* sloppy
  // about dealing with modifiers. This will ultimately bite us, one day.
  const MCSymbolRefExpr *LHS_A = LHS.getSymA();
  const MCSymbolRefExpr *LHS_B = LHS.getSymB();
  int64_t LHS_Cst = LHS.getConstant();

  // Fold the result constant immediately.
  int64_t Result_Cst = LHS_Cst + RHS_Cst;

  assert((!Layout || Asm) &&
         "Must have an assembler object if layout is given!");

  // If we have a layout, we can fold resolved differences.
  if (Asm) {
    // First, fold out any differences which are fully resolved. By
    // reassociating terms in
    //   Result = (LHS_A - LHS_B + LHS_Cst) + (RHS_A - RHS_B + RHS_Cst).
    // we have the four possible differences:
    //   (LHS_A - LHS_B),
    //   (LHS_A - RHS_B),
    //   (RHS_A - LHS_B),
    //   (RHS_A - RHS_B).
    // Since we are attempting to be as aggressive as possible about folding, we
    // attempt to evaluate each possible alternative.
    AttemptToFoldSymbolOffsetDifference(Asm, Layout, Addrs, InSet, LHS_A, LHS_B,
                                        Result_Cst);
    AttemptToFoldSymbolOffsetDifference(Asm, Layout, Addrs, InSet, LHS_A, RHS_B,
                                        Result_Cst);
    AttemptToFoldSymbolOffsetDifference(Asm, Layout, Addrs, InSet, RHS_A, LHS_B,
                                        Result_Cst);
    AttemptToFoldSymbolOffsetDifference(Asm, Layout, Addrs, InSet, RHS_A, RHS_B,
                                        Result_Cst);
  }

  // We can't represent the addition or subtraction of two symbols.
  if ((LHS_A && RHS_A) || (LHS_B && RHS_B))
    return false;

  // At this point, we have at most one additive symbol and one subtractive
  // symbol -- find them.
  const MCSymbolRefExpr *A = LHS_A ? LHS_A : RHS_A;
  const MCSymbolRefExpr *B = LHS_B ? LHS_B : RHS_B;

  // If we have a negated symbol, then we must have also have a non-negated
  // symbol in order to encode the expression.
  if (B && !A)
    return false;

  Res = MCValue::get(A, B, Result_Cst);
  return true;
}
Exemplo n.º 9
0
bool AsmExpr::EvaluateAsAbsolute(MCContext &Ctx, int64_t &Res) const {
  MCValue Value;
  
  if (!EvaluateAsRelocatable(Ctx, Value) || !Value.isAbsolute())
    return false;

  Res = Value.getConstant();
  return true;
}
bool MCExpr::EvaluateAsAbsolute(int64_t &Res) const {
  MCValue Value;
  
  if (!EvaluateAsRelocatable(Value) || !Value.isAbsolute())
    return false;

  Res = Value.getConstant();
  return true;
}
Exemplo n.º 11
0
bool AArch64MCExpr::EvaluateAsRelocatableImpl(MCValue &Res,
                                            const MCAsmLayout *Layout,
					    const MCFixup *Fixup) const {
  if (!getSubExpr()->EvaluateAsRelocatable(Res, Layout, Fixup))
    return false;

  Res =
      MCValue::get(Res.getSymA(), Res.getSymB(), Res.getConstant(), getKind());

  return true;
}
Exemplo n.º 12
0
bool
PPCMCExpr::evaluateAsConstant(int64_t &Res) const {
  MCValue Value;

  if (!getSubExpr()->evaluateAsRelocatable(Value, nullptr, nullptr))
    return false;

  if (!Value.isAbsolute())
    return false;

  Res = evaluateAsInt64(Value.getConstant());
  return true;
}
Exemplo n.º 13
0
static MCSymbolRefExpr::VariantKind getAccessVariant(const MCValue &Target,
                                                     const MCFixup &Fixup) {
  const MCExpr *Expr = Fixup.getValue();

  if (Expr->getKind() != MCExpr::Target)
    return Target.getAccessVariant();

  switch (cast<PPCMCExpr>(Expr)->getKind()) {
  case PPCMCExpr::VK_PPC_None:
    return MCSymbolRefExpr::VK_None;
  case PPCMCExpr::VK_PPC_LO:
    return MCSymbolRefExpr::VK_PPC_LO;
  case PPCMCExpr::VK_PPC_HI:
    return MCSymbolRefExpr::VK_PPC_HI;
  case PPCMCExpr::VK_PPC_HA:
    return MCSymbolRefExpr::VK_PPC_HA;
  case PPCMCExpr::VK_PPC_HIGHERA:
    return MCSymbolRefExpr::VK_PPC_HIGHERA;
  case PPCMCExpr::VK_PPC_HIGHER:
    return MCSymbolRefExpr::VK_PPC_HIGHER;
  case PPCMCExpr::VK_PPC_HIGHEST:
    return MCSymbolRefExpr::VK_PPC_HIGHEST;
  case PPCMCExpr::VK_PPC_HIGHESTA:
    return MCSymbolRefExpr::VK_PPC_HIGHESTA;
  }
  llvm_unreachable("unknown PPCMCExpr kind");
}
Exemplo n.º 14
0
bool RISCVMCExpr::evaluateAsConstant(int64_t &Res) const {
  MCValue Value;

  if (Kind == VK_RISCV_PCREL_HI || Kind == VK_RISCV_PCREL_LO ||
      Kind == VK_RISCV_CALL)
    return false;

  if (!getSubExpr()->evaluateAsRelocatable(Value, nullptr, nullptr))
    return false;

  if (!Value.isAbsolute())
    return false;

  Res = evaluateAsInt64(Value.getConstant());
  return true;
}
Exemplo n.º 15
0
void MachObjectWriter::markAbsoluteVariableSymbols(MCAssembler &Asm,
                                                   const MCAsmLayout &Layout) {
  for (MCSymbolData &SD : Asm.symbols()) {
    if (!SD.getSymbol().isVariable())
      continue;

    // Is the variable is a symbol difference (SA - SB + C) expression,
    // and neither symbol is external, mark the variable as absolute.
    const MCExpr *Expr = SD.getSymbol().getVariableValue();
    MCValue Value;
    if (Expr->EvaluateAsRelocatable(Value, &Layout, nullptr)) {
      if (Value.getSymA() && Value.getSymB())
        const_cast<MCSymbol*>(&SD.getSymbol())->setAbsolute();
    }
  }
}
Exemplo n.º 16
0
void X86MachObjectWriter::RecordTLVPRelocation(MachObjectWriter *Writer,
                                               const MCAssembler &Asm,
                                               const MCAsmLayout &Layout,
                                               const MCFragment *Fragment,
                                               const MCFixup &Fixup,
                                               MCValue Target,
                                               uint64_t &FixedValue) {
  assert(Target.getSymA()->getKind() == MCSymbolRefExpr::VK_TLVP &&
         !is64Bit() &&
         "Should only be called with a 32-bit TLVP relocation!");

  unsigned Log2Size = getFixupKindLog2Size(Fixup.getKind());
  uint32_t Value = Layout.getFragmentOffset(Fragment)+Fixup.getOffset();
  unsigned IsPCRel = 0;

  // Get the symbol data.
  const MCSymbolData *SD_A = &Asm.getSymbolData(Target.getSymA()->getSymbol());
  unsigned Index = SD_A->getIndex();

  // We're only going to have a second symbol in pic mode and it'll be a
  // subtraction from the picbase. For 32-bit pic the addend is the difference
  // between the picbase and the next address.  For 32-bit static the addend is
  // zero.
  if (Target.getSymB()) {
    // If this is a subtraction then we're pcrel.
    uint32_t FixupAddress =
      Writer->getFragmentAddress(Fragment, Layout) + Fixup.getOffset();
    const MCSymbolData *SD_B =
        &Asm.getSymbolData(Target.getSymB()->getSymbol());
    IsPCRel = 1;
    FixedValue = (FixupAddress - Writer->getSymbolAddress(SD_B, Layout) +
                  Target.getConstant());
    FixedValue += 1ULL << Log2Size;
  } else {
    FixedValue = 0;
  }

  // struct relocation_info (8 bytes)
  MachO::any_relocation_info MRE;
  MRE.r_word0 = Value;
  MRE.r_word1 = ((Index                    <<  0) |
                 (IsPCRel                  << 24) |
                 (Log2Size                 << 25) |
                 (1                        << 27) | // r_extern
                 (MachO::GENERIC_RELOC_TLV << 28)); // r_type
  Writer->addRelocation(Fragment->getParent(), MRE);
}
Exemplo n.º 17
0
SVMSymbolInfo SVMMemoryLayout::getSymbol(const MCAssembler &Asm,
    const MCAsmLayout &Layout, MCValue Value, bool useCodeAddresses) const
{
    /*
     * Convert an MCValue into a resolved SVMSymbolInfo,
     * by evaluating (SymA - SymB + Constant).
     */

    int64_t CValue = Value.getConstant();
    const MCSymbolRefExpr *SA = Value.getSymA();
    const MCSymbolRefExpr *SB = Value.getSymB();
    SVMSymbolInfo SIA, SIB;
    
    if (SA) SIA = getSymbol(Asm, Layout, &SA->getSymbol(), useCodeAddresses);
    if (SB) SIB = getSymbol(Asm, Layout, &SB->getSymbol(), useCodeAddresses);

    if ((SIA.Kind == SVMSymbolInfo::NONE || SIA.Kind == SVMSymbolInfo::LOCAL) &&
        (SIB.Kind == SVMSymbolInfo::NONE || SIB.Kind == SVMSymbolInfo::LOCAL)) {

        // Arithmetic is allowed.
        SIA.Kind = SVMSymbolInfo::LOCAL;
        SIA.Value = CValue + SIA.Value - SIB.Value;
        return SIA;
    }

    if (SIA.Kind == SIB.Kind && SIA.Value == SIB.Value) {
        // Two special symbols cancel out, yield a normal constant
        SIA.Kind = SVMSymbolInfo::LOCAL;
        SIA.Value = CValue;
        return SIA;
    }

    if (SIA.Kind != SVMSymbolInfo::NONE && SIB.Kind != SVMSymbolInfo::NONE)
        report_fatal_error("Can't take the difference of special symbols '"
            + Twine(SA->getSymbol().getName()) + "' and '"
            + Twine(SB->getSymbol().getName()) + "'");

    if (SIB.Kind != SVMSymbolInfo::NONE)
        report_fatal_error("Can't negate special symbol '"
            + Twine(SB->getSymbol().getName()) + "'");

    if (CValue != 0)
        report_fatal_error("Can't add constant to special symbol '"
            + Twine(SA->getSymbol().getName()) + "'");

    return SIA;
}
Exemplo n.º 18
0
// Try to fully compute Expr to an absolute value and if that fails produce
// a relocatable expr.
// FIXME: Should this be the behavior of EvaluateAsRelocatable itself?
static bool evaluate(const MCExpr &Expr, const MCAsmLayout &Layout,
                     const MCFixup &Fixup, MCValue &Target) {
  if (Expr.EvaluateAsValue(Target, &Layout, &Fixup)) {
    if (Target.isAbsolute())
      return true;
  }
  return Expr.EvaluateAsRelocatable(Target, &Layout, &Fixup);
}
Exemplo n.º 19
0
static bool isScatteredFixupFullyResolved(const MCAssembler &Asm,
                                          const MCAsmLayout &Layout,
                                          const MCFixup &Fixup,
                                          const MCValue Target,
                                          const MCSymbolData *BaseSymbol) {
  // The effective fixup address is
  //     addr(atom(A)) + offset(A)
  //   - addr(atom(B)) - offset(B)
  //   - addr(BaseSymbol) + <fixup offset from base symbol>
  // and the offsets are not relocatable, so the fixup is fully resolved when
  //  addr(atom(A)) - addr(atom(B)) - addr(BaseSymbol) == 0.
  //
  // Note that "false" is almost always conservatively correct (it means we emit
  // a relocation which is unnecessary), except when it would force us to emit a
  // relocation which the target cannot encode.

  const MCSymbolData *A_Base = 0, *B_Base = 0;
  if (const MCSymbolRefExpr *A = Target.getSymA()) {
    // Modified symbol references cannot be resolved.
    if (A->getKind() != MCSymbolRefExpr::VK_None)
      return false;

    A_Base = Asm.getAtom(Layout, &Asm.getSymbolData(A->getSymbol()));
    if (!A_Base)
      return false;
  }

  if (const MCSymbolRefExpr *B = Target.getSymB()) {
    // Modified symbol references cannot be resolved.
    if (B->getKind() != MCSymbolRefExpr::VK_None)
      return false;

    B_Base = Asm.getAtom(Layout, &Asm.getSymbolData(B->getSymbol()));
    if (!B_Base)
      return false;
  }

  // If there is no base, A and B have to be the same atom for this fixup to be
  // fully resolved.
  if (!BaseSymbol)
    return A_Base == B_Base;

  // Otherwise, B must be missing and A must be the base.
  return !B_Base && BaseSymbol == A_Base;
}
Exemplo n.º 20
0
unsigned AMDGPUELFObjectWriter::getRelocType(MCContext &Ctx,
                                             const MCValue &Target,
                                             const MCFixup &Fixup,
                                             bool IsPCRel) const {
  // SCRATCH_RSRC_DWORD[01] is a special global variable that represents
  // the scratch buffer.
  if (Target.getSymA()->getSymbol().getName() == "SCRATCH_RSRC_DWORD0")
    return ELF::R_AMDGPU_ABS32_LO;
  if (Target.getSymA()->getSymbol().getName() == "SCRATCH_RSRC_DWORD1")
    return ELF::R_AMDGPU_ABS32_HI;

  switch (Fixup.getKind()) {
  default: break;
  case FK_PCRel_4:
    return ELF::R_AMDGPU_REL32;
  }

  llvm_unreachable("unhandled relocation type");
}
Exemplo n.º 21
0
unsigned X86ELFObjectWriter::GetRelocType(const MCValue &Target,
                                          const MCFixup &Fixup,
                                          bool IsPCRel) const {
  MCSymbolRefExpr::VariantKind Modifier = Target.getAccessVariant();
  X86_64RelType Type = getType64(Fixup.getKind(), Modifier, IsPCRel);
  if (getEMachine() == ELF::EM_X86_64)
    return getRelocType64(Modifier, Type, IsPCRel);

  assert(getEMachine() == ELF::EM_386 && "Unsupported ELF machine type.");
  return getRelocType32(Modifier, getType32(Type), IsPCRel);
}
unsigned ARMWinCOFFObjectWriter::getRelocType(MCContext &Ctx,
                                              const MCValue &Target,
                                              const MCFixup &Fixup,
                                              bool IsCrossSection,
                                              const MCAsmBackend &MAB) const {
  assert(getMachine() == COFF::IMAGE_FILE_MACHINE_ARMNT &&
         "AArch64 support not yet implemented");

  MCSymbolRefExpr::VariantKind Modifier =
    Target.isAbsolute() ? MCSymbolRefExpr::VK_None : Target.getSymA()->getKind();

  switch (static_cast<unsigned>(Fixup.getKind())) {
  default: {
    const MCFixupKindInfo &Info = MAB.getFixupKindInfo(Fixup.getKind());
    report_fatal_error(Twine("unsupported relocation type: ") + Info.Name);
  }
  case FK_Data_4:
    switch (Modifier) {
    case MCSymbolRefExpr::VK_COFF_IMGREL32:
      return COFF::IMAGE_REL_ARM_ADDR32NB;
    case MCSymbolRefExpr::VK_SECREL:
      return COFF::IMAGE_REL_ARM_SECREL;
    default:
      return COFF::IMAGE_REL_ARM_ADDR32;
    }
  case FK_SecRel_2:
    return COFF::IMAGE_REL_ARM_SECTION;
  case FK_SecRel_4:
    return COFF::IMAGE_REL_ARM_SECREL;
  case ARM::fixup_t2_condbranch:
    return COFF::IMAGE_REL_ARM_BRANCH20T;
  case ARM::fixup_t2_uncondbranch:
  case ARM::fixup_arm_thumb_bl:
    return COFF::IMAGE_REL_ARM_BRANCH24T;
  case ARM::fixup_arm_thumb_blx:
    return COFF::IMAGE_REL_ARM_BLX23T;
  case ARM::fixup_t2_movw_lo16:
  case ARM::fixup_t2_movt_hi16:
    return COFF::IMAGE_REL_ARM_MOV32T;
  }
}
Exemplo n.º 23
0
const MCSymbol *MCAsmLayout::getBaseSymbol(const MCSymbol &Symbol) const {
  if (!Symbol.isVariable())
    return &Symbol;

  const MCExpr *Expr = Symbol.getVariableValue();
  MCValue Value;
  if (!Expr->EvaluateAsValue(Value, this, nullptr))
    llvm_unreachable("Invalid Expression");

  const MCSymbolRefExpr *RefB = Value.getSymB();
  if (RefB)
    Assembler.getContext().FatalError(
        SMLoc(), Twine("symbol '") + RefB->getSymbol().getName() +
                     "' could not be evaluated in a subtraction expression");

  const MCSymbolRefExpr *A = Value.getSymA();
  if (!A)
    return nullptr;

  return &A->getSymbol();
}
Exemplo n.º 24
0
bool MCExpr::EvaluateAsAbsolute(int64_t &Res, const MCAssembler *Asm,
                                const MCAsmLayout *Layout,
                                const SectionAddrMap *Addrs) const {
  MCValue Value;

  // Fast path constants.
  if (const MCConstantExpr *CE = dyn_cast<MCConstantExpr>(this)) {
    Res = CE->getValue();
    return true;
  }

  // FIXME: The use if InSet = Addrs is a hack. Setting InSet causes us
  // absolutize differences across sections and that is what the MachO writer
  // uses Addrs for.
  bool IsRelocatable =
    EvaluateAsRelocatableImpl(Value, Asm, Layout, Addrs, /*InSet*/ Addrs);

  // Record the current value.
  Res = Value.getConstant();

  return IsRelocatable && Value.isAbsolute();
}
Exemplo n.º 25
0
bool RISCVMCExpr::evaluatePCRelLo(MCValue &Res, const MCAsmLayout *Layout,
                                  const MCFixup *Fixup) const {
  // VK_RISCV_PCREL_LO has to be handled specially.  The MCExpr inside is
  // actually the location of a auipc instruction with a VK_RISCV_PCREL_HI fixup
  // pointing to the real target.  We need to generate an MCValue in the form of
  // (<real target> + <offset from this fixup to the auipc fixup>).  The Fixup
  // is pcrel relative to the VK_RISCV_PCREL_LO fixup, so we need to add the
  // offset to the VK_RISCV_PCREL_HI Fixup from VK_RISCV_PCREL_LO to correct.
  MCValue AUIPCLoc;
  if (!getSubExpr()->evaluateAsValue(AUIPCLoc, *Layout))
    return false;

  const MCSymbolRefExpr *AUIPCSRE = AUIPCLoc.getSymA();
  // Don't try to evaluate %pcrel_hi/%pcrel_lo pairs that cross fragment
  // boundries.
  if (!AUIPCSRE ||
      findAssociatedFragment() != AUIPCSRE->findAssociatedFragment())
    return false;

  const MCSymbol *AUIPCSymbol = &AUIPCSRE->getSymbol();
  if (!AUIPCSymbol)
    return false;

  const MCFixup *TargetFixup = getPCRelHiFixup();
  if (!TargetFixup)
    return false;

  if ((unsigned)TargetFixup->getKind() != RISCV::fixup_riscv_pcrel_hi20)
    return false;

  MCValue Target;
  if (!TargetFixup->getValue()->evaluateAsValue(Target, *Layout))
    return false;

  if (!Target.getSymA() || !Target.getSymA()->getSymbol().isInSection())
    return false;

  if (&Target.getSymA()->getSymbol().getSection() !=
      findAssociatedFragment()->getParent())
    return false;

  uint64_t AUIPCOffset = AUIPCSymbol->getOffset();

  Res = MCValue::get(Target.getSymA(), nullptr,
                     Target.getConstant() + (Fixup->getOffset() - AUIPCOffset));
  return true;
}
Exemplo n.º 26
0
static bool isScatteredFixupFullyResolvedSimple(const MCAssembler &Asm,
                                                const MCFixup &Fixup,
                                                const MCValue Target,
                                                const MCSection *BaseSection) {
  // The effective fixup address is
  //     addr(atom(A)) + offset(A)
  //   - addr(atom(B)) - offset(B)
  //   - addr(<base symbol>) + <fixup offset from base symbol>
  // and the offsets are not relocatable, so the fixup is fully resolved when
  //  addr(atom(A)) - addr(atom(B)) - addr(<base symbol>)) == 0.
  //
  // 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.

  // Non-relative fixups are only resolved if constant.
  if (!BaseSection)
    return Target.isAbsolute();

  // Otherwise, relative fixups are only resolved if not a difference and the
  // target is a temporary in the same section.
  if (Target.isAbsolute() || Target.getSymB())
    return false;

  const MCSymbol *A = &Target.getSymA()->getSymbol();
  if (!A->isTemporary() || !A->isInSection() ||
      &A->getSection() != BaseSection)
    return false;

  return true;
}
Exemplo n.º 27
0
bool RISCVMCExpr::evaluateAsRelocatableImpl(MCValue &Res,
                                            const MCAsmLayout *Layout,
                                            const MCFixup *Fixup) const {
  if (Kind == VK_RISCV_PCREL_LO && evaluatePCRelLo(Res, Layout, Fixup))
    return true;

  if (!getSubExpr()->evaluateAsRelocatable(Res, Layout, Fixup))
    return false;

  // Some custom fixup types are not valid with symbol difference expressions
  if (Res.getSymA() && Res.getSymB()) {
    switch (getKind()) {
    default:
      return true;
    case VK_RISCV_LO:
    case VK_RISCV_HI:
    case VK_RISCV_PCREL_LO:
    case VK_RISCV_PCREL_HI:
      return false;
    }
  }

  return true;
}
Exemplo n.º 28
0
bool
PPCMCExpr::evaluateAsRelocatableImpl(MCValue &Res,
                                     const MCAsmLayout *Layout,
                                     const MCFixup *Fixup) const {
  MCValue Value;

  if (!getSubExpr()->evaluateAsRelocatable(Value, Layout, Fixup))
    return false;

  if (Value.isAbsolute()) {
    int64_t Result = evaluateAsInt64(Value.getConstant());
    if ((Fixup == nullptr || (unsigned)Fixup->getKind() != PPC::fixup_ppc_half16) &&
        (Result >= 0x8000))
      return false;
    Res = MCValue::get(Result);
  } else {
    if (!Layout)
      return false;

    MCContext &Context = Layout->getAssembler().getContext();
    const MCSymbolRefExpr *Sym = Value.getSymA();
    MCSymbolRefExpr::VariantKind Modifier = Sym->getKind();
    if (Modifier != MCSymbolRefExpr::VK_None)
      return false;
    switch (Kind) {
      default:
        llvm_unreachable("Invalid kind!");
      case VK_PPC_LO:
        Modifier = MCSymbolRefExpr::VK_PPC_LO;
        break;
      case VK_PPC_HI:
        Modifier = MCSymbolRefExpr::VK_PPC_HI;
        break;
      case VK_PPC_HA:
        Modifier = MCSymbolRefExpr::VK_PPC_HA;
        break;
      case VK_PPC_HIGHERA:
        Modifier = MCSymbolRefExpr::VK_PPC_HIGHERA;
        break;
      case VK_PPC_HIGHER:
        Modifier = MCSymbolRefExpr::VK_PPC_HIGHER;
        break;
      case VK_PPC_HIGHEST:
        Modifier = MCSymbolRefExpr::VK_PPC_HIGHEST;
        break;
      case VK_PPC_HIGHESTA:
        Modifier = MCSymbolRefExpr::VK_PPC_HIGHESTA;
        break;
    }
    Sym = MCSymbolRefExpr::create(&Sym->getSymbol(), Modifier, Context);
    Res = MCValue::get(Sym, Value.getSymB(), Value.getConstant());
  }

  return true;
}
unsigned SystemZObjectWriter::getRelocType(MCContext &Ctx,
                                           const MCValue &Target,
                                           const MCFixup &Fixup,
                                           bool IsPCRel) const {
  MCSymbolRefExpr::VariantKind Modifier = Target.getAccessVariant();
  unsigned Kind = Fixup.getKind();
  switch (Modifier) {
  case MCSymbolRefExpr::VK_None:
    if (IsPCRel)
      return getPCRelReloc(Kind);
    return getAbsoluteReloc(Kind);

  case MCSymbolRefExpr::VK_NTPOFF:
    assert(!IsPCRel && "NTPOFF shouldn't be PC-relative");
    return getTLSLEReloc(Kind);

  case MCSymbolRefExpr::VK_INDNTPOFF:
    if (IsPCRel && Kind == SystemZ::FK_390_PC32DBL)
      return ELF::R_390_TLS_IEENT;
    llvm_unreachable("Only PC-relative INDNTPOFF accesses are supported for now");

  case MCSymbolRefExpr::VK_DTPOFF:
    assert(!IsPCRel && "DTPOFF shouldn't be PC-relative");
    return getTLSLDOReloc(Kind);

  case MCSymbolRefExpr::VK_TLSLDM:
    assert(!IsPCRel && "TLSLDM shouldn't be PC-relative");
    return getTLSLDMReloc(Kind);

  case MCSymbolRefExpr::VK_TLSGD:
    assert(!IsPCRel && "TLSGD shouldn't be PC-relative");
    return getTLSGDReloc(Kind);

  case MCSymbolRefExpr::VK_GOT:
    if (IsPCRel && Kind == SystemZ::FK_390_PC32DBL)
      return ELF::R_390_GOTENT;
    llvm_unreachable("Only PC-relative GOT accesses are supported for now");

  case MCSymbolRefExpr::VK_PLT:
    assert(IsPCRel && "@PLT shouldt be PC-relative");
    return getPLTReloc(Kind);

  default:
    llvm_unreachable("Modifier not supported");
  }
}
static bool EvaluateSymbolicAdd(const MCValue &LHS, const MCSymbol *RHS_A, 
                                const MCSymbol *RHS_B, int64_t RHS_Cst,
                                MCValue &Res) {
  // We can't add or subtract two symbols.
  if ((LHS.getSymA() && RHS_A) ||
      (LHS.getSymB() && RHS_B))
    return false;

  const MCSymbol *A = LHS.getSymA() ? LHS.getSymA() : RHS_A;
  const MCSymbol *B = LHS.getSymB() ? LHS.getSymB() : RHS_B;
  if (B) {
    // If we have a negated symbol, then we must have also have a non-negated
    // symbol in order to encode the expression. We can do this check later to
    // permit expressions which eventually fold to a representable form -- such
    // as (a + (0 - b)) -- if necessary.
    if (!A)
      return false;
  }
  Res = MCValue::get(A, B, LHS.getConstant() + RHS_Cst);
  return true;
}