C++ LValue::isVolatileQualified方法代码示例

/// EmitStoreOfComplex - Store the specified real/imag parts into the
/// specified value pointer.
void ComplexExprEmitter::EmitStoreOfComplex(ComplexPairTy Val, LValue lvalue,
                                            bool isInit) {
  if (lvalue.getType()->isAtomicType() ||
      (!isInit && CGF.LValueIsSuitableForInlineAtomic(lvalue)))
    return CGF.EmitAtomicStore(RValue::getComplex(Val), lvalue, isInit);

  Address Ptr = lvalue.getAddress();
  Address RealPtr = CGF.emitAddrOfRealComponent(Ptr, lvalue.getType());
  Address ImagPtr = CGF.emitAddrOfImagComponent(Ptr, lvalue.getType());

  Builder.CreateStore(Val.first, RealPtr, lvalue.isVolatileQualified());
  Builder.CreateStore(Val.second, ImagPtr, lvalue.isVolatileQualified());
}

/// EmitStoreOfComplex - Store the specified real/imag parts into the
/// specified value pointer.
void ComplexExprEmitter::EmitStoreOfComplex(ComplexPairTy Val,
                                            LValue lvalue,
                                            bool isInit) {
  if (lvalue.getType()->isAtomicType())
    return CGF.EmitAtomicStore(RValue::getComplex(Val), lvalue, isInit);

  llvm::Value *Ptr = lvalue.getAddress();
  llvm::Value *RealPtr = Builder.CreateStructGEP(Ptr, 0, "real");
  llvm::Value *ImagPtr = Builder.CreateStructGEP(Ptr, 1, "imag");

  // TODO: alignment
  Builder.CreateStore(Val.first, RealPtr, lvalue.isVolatileQualified());
  Builder.CreateStore(Val.second, ImagPtr, lvalue.isVolatileQualified());
}

ComplexPairTy ComplexExprEmitter::VisitBinAssign(const BinaryOperator *E) {
    ComplexPairTy Val;
    LValue LV = EmitBinAssignLValue(E, Val);

    // The result of an assignment in C is the assigned r-value.
    if (!CGF.getContext().getLangOptions().CPlusPlus)
        return Val;

    // If the lvalue is non-volatile, return the computed value of the assignment.
    if (!LV.isVolatileQualified())
        return Val;

    return EmitLoadOfComplex(LV.getAddress(), LV.isVolatileQualified());
}

void AggExprEmitter::VisitBinAssign(const BinaryOperator *E) {
  // For an assignment to work, the value on the right has
  // to be compatible with the value on the left.
  assert(CGF.getContext().hasSameUnqualifiedType(E->getLHS()->getType(),
                                                 E->getRHS()->getType())
         && "Invalid assignment");
  LValue LHS = CGF.EmitLValue(E->getLHS());

  // We have to special case property setters, otherwise we must have
  // a simple lvalue (no aggregates inside vectors, bitfields).
  if (LHS.isPropertyRef()) {
    llvm::Value *AggLoc = DestPtr;
    if (!AggLoc)
      AggLoc = CGF.CreateMemTemp(E->getRHS()->getType());
    CGF.EmitAggExpr(E->getRHS(), AggLoc, VolatileDest);
    CGF.EmitObjCPropertySet(LHS.getPropertyRefExpr(),
                            RValue::getAggregate(AggLoc, VolatileDest));
  } else if (LHS.isKVCRef()) {
    llvm::Value *AggLoc = DestPtr;
    if (!AggLoc)
      AggLoc = CGF.CreateMemTemp(E->getRHS()->getType());
    CGF.EmitAggExpr(E->getRHS(), AggLoc, VolatileDest);
    CGF.EmitObjCPropertySet(LHS.getKVCRefExpr(),
                            RValue::getAggregate(AggLoc, VolatileDest));
  } else {
    bool RequiresGCollection = false;
    if (CGF.getContext().getLangOptions().getGCMode())
      RequiresGCollection = TypeRequiresGCollection(E->getLHS()->getType());

    // Codegen the RHS so that it stores directly into the LHS.
    CGF.EmitAggExpr(E->getRHS(), LHS.getAddress(), LHS.isVolatileQualified(),
                    false, false, RequiresGCollection);
    EmitFinalDestCopy(E, LHS, true);
  }
}

/// EmitFinalDestCopy - Perform the final copy to DestPtr, if desired.
void AggExprEmitter::EmitFinalDestCopy(const Expr *E, LValue Src, bool Ignore) {
  assert(Src.isSimple() && "Can't have aggregate bitfield, vector, etc");

  EmitFinalDestCopy(E, RValue::getAggregate(Src.getAddress(),
                                            Src.isVolatileQualified()),
                    Ignore);
}

/// Copy an r-value into memory as part of storing to an atomic type.
/// This needs to create a bit-pattern suitable for atomic operations.
void AtomicInfo::emitCopyIntoMemory(RValue rvalue, LValue dest) const {
  // If we have an r-value, the rvalue should be of the atomic type,
  // which means that the caller is responsible for having zeroed
  // any padding.  Just do an aggregate copy of that type.
  if (rvalue.isAggregate()) {
    CGF.EmitAggregateCopy(dest.getAddress(),
                          rvalue.getAggregateAddr(),
                          getAtomicType(),
                          (rvalue.isVolatileQualified()
                           || dest.isVolatileQualified()),
                          dest.getAlignment());
    return;
  }

  // Okay, otherwise we're copying stuff.

  // Zero out the buffer if necessary.
  emitMemSetZeroIfNecessary(dest);

  // Drill past the padding if present.
  dest = projectValue(dest);

  // Okay, store the rvalue in.
  if (rvalue.isScalar()) {
    CGF.EmitStoreOfScalar(rvalue.getScalarVal(), dest, /*init*/ true);
  } else {
    CGF.EmitStoreOfComplex(rvalue.getComplexVal(), dest, /*init*/ true);
  }
}

LValue CodeGenFunction::EmitAggExprToLValue(const Expr *E) {
  assert(hasAggregateLLVMType(E->getType()) && "Invalid argument!");
  llvm::Value *Temp = CreateMemTemp(E->getType());
  LValue LV = MakeAddrLValue(Temp, E->getType());
  EmitAggExpr(E, Temp, LV.isVolatileQualified());
  return LV;
}

/// EmitLoadOfLValue - Given an RValue reference for a complex, emit code to
/// load the real and imaginary pieces, returning them as Real/Imag.
ComplexPairTy ComplexExprEmitter::EmitLoadOfLValue(LValue lvalue,
                                                   SourceLocation loc) {
  assert(lvalue.isSimple() && "non-simple complex l-value?");
  if (lvalue.getType()->isAtomicType())
    return CGF.EmitAtomicLoad(lvalue, loc).getComplexVal();

  llvm::Value *SrcPtr = lvalue.getAddress();
  bool isVolatile = lvalue.isVolatileQualified();
  unsigned AlignR = lvalue.getAlignment().getQuantity();
  ASTContext &C = CGF.getContext();
  QualType ComplexTy = lvalue.getType();
  unsigned ComplexAlign = C.getTypeAlignInChars(ComplexTy).getQuantity();
  unsigned AlignI = std::min(AlignR, ComplexAlign);

  llvm::Value *Real=nullptr, *Imag=nullptr;

  if (!IgnoreReal || isVolatile) {
    llvm::Value *RealP = Builder.CreateStructGEP(SrcPtr, 0,
                                                 SrcPtr->getName() + ".realp");
    Real = Builder.CreateAlignedLoad(RealP, AlignR, isVolatile,
                                     SrcPtr->getName() + ".real");
  }

  if (!IgnoreImag || isVolatile) {
    llvm::Value *ImagP = Builder.CreateStructGEP(SrcPtr, 1,
                                                 SrcPtr->getName() + ".imagp");
    Imag = Builder.CreateAlignedLoad(ImagP, AlignI, isVolatile,
                                     SrcPtr->getName() + ".imag");
  }
  return ComplexPairTy(Real, Imag);
}

/// EmitStoreOfComplex - Store the specified real/imag parts into the
/// specified value pointer.
void ComplexExprEmitter::EmitStoreOfComplex(ComplexPairTy Val, LValue lvalue,
                                            bool isInit) {
  if (lvalue.getType()->isAtomicType())
    return CGF.EmitAtomicStore(RValue::getComplex(Val), lvalue, isInit);

  llvm::Value *Ptr = lvalue.getAddress();
  llvm::Value *RealPtr = Builder.CreateStructGEP(Ptr, 0, "real");
  llvm::Value *ImagPtr = Builder.CreateStructGEP(Ptr, 1, "imag");
  unsigned AlignR = lvalue.getAlignment().getQuantity();
  ASTContext &C = CGF.getContext();
  QualType ComplexTy = lvalue.getType();
  unsigned ComplexAlign = C.getTypeAlignInChars(ComplexTy).getQuantity();
  unsigned AlignI = std::min(AlignR, ComplexAlign);

  Builder.CreateAlignedStore(Val.first, RealPtr, AlignR,
                             lvalue.isVolatileQualified());
  Builder.CreateAlignedStore(Val.second, ImagPtr, AlignI,
                             lvalue.isVolatileQualified());
}

/// Emit a store to an l-value of atomic type.
///
/// Note that the r-value is expected to be an r-value *of the atomic
/// type*; this means that for aggregate r-values, it should include
/// storage for any padding that was necessary.
void CodeGenFunction::EmitAtomicStore(RValue rvalue, LValue dest, bool isInit) {
  // If this is an aggregate r-value, it should agree in type except
  // maybe for address-space qualification.
  assert(!rvalue.isAggregate() ||
         rvalue.getAggregateAddr()->getType()->getPointerElementType()
           == dest.getAddress()->getType()->getPointerElementType());

  AtomicInfo atomics(*this, dest);

  // If this is an initialization, just put the value there normally.
  if (isInit) {
    atomics.emitCopyIntoMemory(rvalue, dest);
    return;
  }

  // Check whether we should use a library call.
  if (atomics.shouldUseLibcall()) {
    // Produce a source address.
    llvm::Value *srcAddr = atomics.materializeRValue(rvalue);

    // void __atomic_store(size_t size, void *mem, void *val, int order)
    CallArgList args;
    args.add(RValue::get(atomics.getAtomicSizeValue()),
             getContext().getSizeType());
    args.add(RValue::get(EmitCastToVoidPtr(dest.getAddress())),
             getContext().VoidPtrTy);
    args.add(RValue::get(EmitCastToVoidPtr(srcAddr)),
             getContext().VoidPtrTy);
    args.add(RValue::get(llvm::ConstantInt::get(
                 IntTy, AtomicExpr::AO_ABI_memory_order_seq_cst)),
             getContext().IntTy);
    emitAtomicLibcall(*this, "__atomic_store", getContext().VoidTy, args);
    return;
  }

  // Okay, we're doing this natively.
  llvm::Value *intValue = atomics.convertRValueToInt(rvalue);

  // Do the atomic store.
  llvm::Value *addr = atomics.emitCastToAtomicIntPointer(dest.getAddress());
  llvm::StoreInst *store = Builder.CreateStore(intValue, addr);

  // Initializations don't need to be atomic.
  if (!isInit) store->setAtomic(llvm::SequentiallyConsistent);

  // Other decoration.
  store->setAlignment(dest.getAlignment().getQuantity());
  if (dest.isVolatileQualified())
    store->setVolatile(true);
  if (dest.getTBAAInfo())
    CGM.DecorateInstruction(store, dest.getTBAAInfo());
}

/// Emit a load from an l-value of atomic type.  Note that the r-value
/// we produce is an r-value of the atomic *value* type.
RValue CodeGenFunction::EmitAtomicLoad(LValue src, SourceLocation loc,
                                       AggValueSlot resultSlot) {
  AtomicInfo atomics(*this, src);

  // Check whether we should use a library call.
  if (atomics.shouldUseLibcall()) {
    llvm::Value *tempAddr;
    if (!resultSlot.isIgnored()) {
      assert(atomics.getEvaluationKind() == TEK_Aggregate);
      tempAddr = resultSlot.getAddr();
    } else {
      tempAddr = CreateMemTemp(atomics.getAtomicType(), "atomic-load-temp");
    }

    // void __atomic_load(size_t size, void *mem, void *return, int order);
    CallArgList args;
    args.add(RValue::get(atomics.getAtomicSizeValue()),
             getContext().getSizeType());
    args.add(RValue::get(EmitCastToVoidPtr(src.getAddress())),
             getContext().VoidPtrTy);
    args.add(RValue::get(EmitCastToVoidPtr(tempAddr)),
             getContext().VoidPtrTy);
    args.add(RValue::get(llvm::ConstantInt::get(
                 IntTy, AtomicExpr::AO_ABI_memory_order_seq_cst)),
             getContext().IntTy);
    emitAtomicLibcall(*this, "__atomic_load", getContext().VoidTy, args);

    // Produce the r-value.
    return atomics.convertTempToRValue(tempAddr, resultSlot, loc);
  }

  // Okay, we're doing this natively.
  llvm::Value *addr = atomics.emitCastToAtomicIntPointer(src.getAddress());
  llvm::LoadInst *load = Builder.CreateLoad(addr, "atomic-load");
  load->setAtomic(llvm::SequentiallyConsistent);

  // Other decoration.
  load->setAlignment(src.getAlignment().getQuantity());
  if (src.isVolatileQualified())
    load->setVolatile(true);
  if (src.getTBAAInfo())
    CGM.DecorateInstruction(load, src.getTBAAInfo());

  // If we're ignoring an aggregate return, don't do anything.
  if (atomics.getEvaluationKind() == TEK_Aggregate && resultSlot.isIgnored())
    return RValue::getAggregate(nullptr, false);

  // Okay, turn that back into the original value type.
  return atomics.convertIntToValue(load, resultSlot, loc);
}

// Compound assignments.
ComplexPairTy ComplexExprEmitter::
EmitCompoundAssign(const CompoundAssignOperator *E,
                   ComplexPairTy (ComplexExprEmitter::*Func)(const BinOpInfo&)){
  ComplexPairTy Val;
  LValue LV = EmitCompoundAssignLValue(E, Func, Val);

  // The result of an assignment in C is the assigned r-value.
  if (!CGF.getLangOpts().CPlusPlus)
    return Val;

  // If the lvalue is non-volatile, return the computed value of the assignment.
  if (!LV.isVolatileQualified())
    return Val;

  return EmitLoadOfLValue(LV);
}

/// EmitLoadOfLValue - Given an RValue reference for a complex, emit code to
/// load the real and imaginary pieces, returning them as Real/Imag.
ComplexPairTy ComplexExprEmitter::EmitLoadOfLValue(LValue lvalue,
                                                   SourceLocation loc) {
  assert(lvalue.isSimple() && "non-simple complex l-value?");
  if (lvalue.getType()->isAtomicType())
    return CGF.EmitAtomicLoad(lvalue, loc).getComplexVal();

  Address SrcPtr = lvalue.getAddress();
  bool isVolatile = lvalue.isVolatileQualified();

  llvm::Value *Real = nullptr, *Imag = nullptr;

  if (!IgnoreReal || isVolatile) {
    Address RealP = CGF.emitAddrOfRealComponent(SrcPtr, lvalue.getType());
    Real = Builder.CreateLoad(RealP, isVolatile, SrcPtr.getName() + ".real");
  }

  if (!IgnoreImag || isVolatile) {
    Address ImagP = CGF.emitAddrOfImagComponent(SrcPtr, lvalue.getType());
    Imag = Builder.CreateLoad(ImagP, isVolatile, SrcPtr.getName() + ".imag");
  }

  return ComplexPairTy(Real, Imag);
}

/// Emit a compare-and-exchange op for atomic type.
///
std::pair<RValue, RValue> CodeGenFunction::EmitAtomicCompareExchange(
    LValue Obj, RValue Expected, RValue Desired, SourceLocation Loc,
    llvm::AtomicOrdering Success, llvm::AtomicOrdering Failure, bool IsWeak,
    AggValueSlot Slot) {
  // If this is an aggregate r-value, it should agree in type except
  // maybe for address-space qualification.
  assert(!Expected.isAggregate() ||
         Expected.getAggregateAddr()->getType()->getPointerElementType() ==
             Obj.getAddress()->getType()->getPointerElementType());
  assert(!Desired.isAggregate() ||
         Desired.getAggregateAddr()->getType()->getPointerElementType() ==
             Obj.getAddress()->getType()->getPointerElementType());
  AtomicInfo Atomics(*this, Obj);

  if (Failure >= Success)
    // Don't assert on undefined behavior.
    Failure = llvm::AtomicCmpXchgInst::getStrongestFailureOrdering(Success);

  auto Alignment = Atomics.getValueAlignment();
  // Check whether we should use a library call.
  if (Atomics.shouldUseLibcall()) {
    auto *ExpectedAddr = Atomics.materializeRValue(Expected);
    // Produce a source address.
    auto *DesiredAddr = Atomics.materializeRValue(Desired);
    // bool __atomic_compare_exchange(size_t size, void *obj, void *expected,
    // void *desired, int success, int failure);
    CallArgList Args;
    Args.add(RValue::get(Atomics.getAtomicSizeValue()),
             getContext().getSizeType());
    Args.add(RValue::get(EmitCastToVoidPtr(Obj.getAddress())),
             getContext().VoidPtrTy);
    Args.add(RValue::get(EmitCastToVoidPtr(ExpectedAddr)),
             getContext().VoidPtrTy);
    Args.add(RValue::get(EmitCastToVoidPtr(DesiredAddr)),
             getContext().VoidPtrTy);
    Args.add(RValue::get(llvm::ConstantInt::get(IntTy, Success)),
             getContext().IntTy);
    Args.add(RValue::get(llvm::ConstantInt::get(IntTy, Failure)),
             getContext().IntTy);
    auto SuccessFailureRVal = emitAtomicLibcall(
        *this, "__atomic_compare_exchange", getContext().BoolTy, Args);
    auto *PreviousVal =
        Builder.CreateAlignedLoad(ExpectedAddr, Alignment.getQuantity());
    return std::make_pair(RValue::get(PreviousVal), SuccessFailureRVal);
  }

  // If we've got a scalar value of the right size, try to avoid going
  // through memory.
  auto *ExpectedIntVal = Atomics.convertRValueToInt(Expected);
  auto *DesiredIntVal = Atomics.convertRValueToInt(Desired);

  // Do the atomic store.
  auto *Addr = Atomics.emitCastToAtomicIntPointer(Obj.getAddress());
  auto *Inst = Builder.CreateAtomicCmpXchg(Addr, ExpectedIntVal, DesiredIntVal,
                                          Success, Failure);
  // Other decoration.
  Inst->setVolatile(Obj.isVolatileQualified());
  Inst->setWeak(IsWeak);

  // Okay, turn that back into the original value type.
  auto *PreviousVal = Builder.CreateExtractValue(Inst, /*Idxs=*/0);
  auto *SuccessFailureVal = Builder.CreateExtractValue(Inst, /*Idxs=*/1);
  return std::make_pair(Atomics.convertIntToValue(PreviousVal, Slot, Loc),
                        RValue::get(SuccessFailureVal));
}

/// Emit a store to an l-value of atomic type.
///
/// Note that the r-value is expected to be an r-value *of the atomic
/// type*; this means that for aggregate r-values, it should include
/// storage for any padding that was necessary.
void CodeGenFunction::EmitAtomicStore(RValue rvalue, LValue dest, bool isInit) {
  // If this is an aggregate r-value, it should agree in type except
  // maybe for address-space qualification.
  assert(!rvalue.isAggregate() ||
         rvalue.getAggregateAddr()->getType()->getPointerElementType()
           == dest.getAddress()->getType()->getPointerElementType());

  AtomicInfo atomics(*this, dest);

  // If this is an initialization, just put the value there normally.
  if (isInit) {
    atomics.emitCopyIntoMemory(rvalue, dest);
    return;
  }

  // Check whether we should use a library call.
  if (atomics.shouldUseLibcall()) {
    // Produce a source address.
    llvm::Value *srcAddr = atomics.materializeRValue(rvalue);

    // void __atomic_store(size_t size, void *mem, void *val, int order)
    CallArgList args;
    args.add(RValue::get(atomics.getAtomicSizeValue()),
             getContext().getSizeType());
    args.add(RValue::get(EmitCastToVoidPtr(dest.getAddress())),
             getContext().VoidPtrTy);
    args.add(RValue::get(EmitCastToVoidPtr(srcAddr)),
             getContext().VoidPtrTy);
    args.add(RValue::get(llvm::ConstantInt::get(
                 IntTy, AtomicExpr::AO_ABI_memory_order_seq_cst)),
             getContext().IntTy);
    emitAtomicLibcall(*this, "__atomic_store", getContext().VoidTy, args);
    return;
  }

  // Okay, we're doing this natively.
  llvm::Value *intValue;

  // If we've got a scalar value of the right size, try to avoid going
  // through memory.
  if (rvalue.isScalar() && !atomics.hasPadding()) {
    llvm::Value *value = rvalue.getScalarVal();
    if (isa<llvm::IntegerType>(value->getType())) {
      intValue = value;
    } else {
      llvm::IntegerType *inputIntTy =
        llvm::IntegerType::get(getLLVMContext(), atomics.getValueSizeInBits());
      if (isa<llvm::PointerType>(value->getType())) {
        intValue = Builder.CreatePtrToInt(value, inputIntTy);
      } else {
        intValue = Builder.CreateBitCast(value, inputIntTy);
      }
    }

  // Otherwise, we need to go through memory.
  } else {
    // Put the r-value in memory.
    llvm::Value *addr = atomics.materializeRValue(rvalue);

    // Cast the temporary to the atomic int type and pull a value out.
    addr = atomics.emitCastToAtomicIntPointer(addr);
    intValue = Builder.CreateAlignedLoad(addr,
                                 atomics.getAtomicAlignment().getQuantity());
  }

  // Do the atomic store.
  llvm::Value *addr = atomics.emitCastToAtomicIntPointer(dest.getAddress());
  llvm::StoreInst *store = Builder.CreateStore(intValue, addr);

  // Initializations don't need to be atomic.
  if (!isInit) store->setAtomic(llvm::SequentiallyConsistent);

  // Other decoration.
  store->setAlignment(dest.getAlignment().getQuantity());
  if (dest.isVolatileQualified())
    store->setVolatile(true);
  if (dest.getTBAAInfo())
    CGM.DecorateInstruction(store, dest.getTBAAInfo());
}