/// This function converts a Constant* into a GenericValue. The interesting
/// part is if C is a ConstantExpr.
/// @brief Get a GenericValue for a Constant*
GenericValue ExecutionEngine::getConstantValue(const Constant *C) {
// If its undefined, return the garbage.
if (isa<UndefValue>(C))
return GenericValue();
// If the value is a ConstantExpr
if (const ConstantExpr *CE = dyn_cast<ConstantExpr>(C)) {
Constant *Op0 = CE->getOperand(0);
switch (CE->getOpcode()) {
case Instruction::GetElementPtr: {
// Compute the index
GenericValue Result = getConstantValue(Op0);
SmallVector<Value*, 8> Indices(CE->op_begin()+1, CE->op_end());
uint64_t Offset =
TD->getIndexedOffset(Op0->getType(), &Indices[0], Indices.size());
char* tmp = (char*) Result.PointerVal;
Result = PTOGV(tmp + Offset);
return Result;
}
case Instruction::Trunc: {
GenericValue GV = getConstantValue(Op0);
uint32_t BitWidth = cast<IntegerType>(CE->getType())->getBitWidth();
GV.IntVal = GV.IntVal.trunc(BitWidth);
return GV;
}
case Instruction::ZExt: {
GenericValue GV = getConstantValue(Op0);
uint32_t BitWidth = cast<IntegerType>(CE->getType())->getBitWidth();
GV.IntVal = GV.IntVal.zext(BitWidth);
return GV;
}
case Instruction::SExt: {
GenericValue GV = getConstantValue(Op0);
uint32_t BitWidth = cast<IntegerType>(CE->getType())->getBitWidth();
GV.IntVal = GV.IntVal.sext(BitWidth);
return GV;
}
case Instruction::FPTrunc: {
// FIXME long double
GenericValue GV = getConstantValue(Op0);
GV.FloatVal = float(GV.DoubleVal);
return GV;
}
case Instruction::FPExt:{
// FIXME long double
GenericValue GV = getConstantValue(Op0);
GV.DoubleVal = double(GV.FloatVal);
return GV;
}
case Instruction::UIToFP: {
GenericValue GV = getConstantValue(Op0);
if (CE->getType() == Type::FloatTy)
GV.FloatVal = float(GV.IntVal.roundToDouble());
else if (CE->getType() == Type::DoubleTy)
GV.DoubleVal = GV.IntVal.roundToDouble();
else if (CE->getType() == Type::X86_FP80Ty) {
const uint64_t zero[] = {0, 0};
APFloat apf = APFloat(APInt(80, 2, zero));
(void)apf.convertFromAPInt(GV.IntVal,
false,
APFloat::rmNearestTiesToEven);
GV.IntVal = apf.bitcastToAPInt();
}
return GV;
}
case Instruction::SIToFP: {
GenericValue GV = getConstantValue(Op0);
if (CE->getType() == Type::FloatTy)
GV.FloatVal = float(GV.IntVal.signedRoundToDouble());
else if (CE->getType() == Type::DoubleTy)
GV.DoubleVal = GV.IntVal.signedRoundToDouble();
else if (CE->getType() == Type::X86_FP80Ty) {
const uint64_t zero[] = { 0, 0};
APFloat apf = APFloat(APInt(80, 2, zero));
(void)apf.convertFromAPInt(GV.IntVal,
true,
APFloat::rmNearestTiesToEven);
GV.IntVal = apf.bitcastToAPInt();
}
return GV;
}
case Instruction::FPToUI: // double->APInt conversion handles sign
case Instruction::FPToSI: {
GenericValue GV = getConstantValue(Op0);
uint32_t BitWidth = cast<IntegerType>(CE->getType())->getBitWidth();
if (Op0->getType() == Type::FloatTy)
GV.IntVal = APIntOps::RoundFloatToAPInt(GV.FloatVal, BitWidth);
else if (Op0->getType() == Type::DoubleTy)
GV.IntVal = APIntOps::RoundDoubleToAPInt(GV.DoubleVal, BitWidth);
else if (Op0->getType() == Type::X86_FP80Ty) {
APFloat apf = APFloat(GV.IntVal);
uint64_t v;
bool ignored;
(void)apf.convertToInteger(&v, BitWidth,
CE->getOpcode()==Instruction::FPToSI,
APFloat::rmTowardZero, &ignored);
GV.IntVal = v; // endian?
}
return GV;
}
case Instruction::PtrToInt: {
GenericValue GV = getConstantValue(Op0);
uint32_t PtrWidth = TD->getPointerSizeInBits();
GV.IntVal = APInt(PtrWidth, uintptr_t(GV.PointerVal));
return GV;
}
case Instruction::IntToPtr: {
GenericValue GV = getConstantValue(Op0);
uint32_t PtrWidth = TD->getPointerSizeInBits();
if (PtrWidth != GV.IntVal.getBitWidth())
GV.IntVal = GV.IntVal.zextOrTrunc(PtrWidth);
assert(GV.IntVal.getBitWidth() <= 64 && "Bad pointer width");
GV.PointerVal = PointerTy(uintptr_t(GV.IntVal.getZExtValue()));
return GV;
}
case Instruction::BitCast: {
GenericValue GV = getConstantValue(Op0);
const Type* DestTy = CE->getType();
switch (Op0->getType()->getTypeID()) {
default: assert(0 && "Invalid bitcast operand");
case Type::IntegerTyID:
assert(DestTy->isFloatingPoint() && "invalid bitcast");
if (DestTy == Type::FloatTy)
GV.FloatVal = GV.IntVal.bitsToFloat();
else if (DestTy == Type::DoubleTy)
GV.DoubleVal = GV.IntVal.bitsToDouble();
break;
case Type::FloatTyID:
assert(DestTy == Type::Int32Ty && "Invalid bitcast");
GV.IntVal.floatToBits(GV.FloatVal);
break;
case Type::DoubleTyID:
assert(DestTy == Type::Int64Ty && "Invalid bitcast");
GV.IntVal.doubleToBits(GV.DoubleVal);
break;
case Type::PointerTyID:
assert(isa<PointerType>(DestTy) && "Invalid bitcast");
break; // getConstantValue(Op0) above already converted it
}
return GV;
}
case Instruction::Add:
case Instruction::Sub:
case Instruction::Mul:
case Instruction::UDiv:
case Instruction::SDiv:
case Instruction::URem:
case Instruction::SRem:
case Instruction::And:
case Instruction::Or:
case Instruction::Xor: {
GenericValue LHS = getConstantValue(Op0);
GenericValue RHS = getConstantValue(CE->getOperand(1));
GenericValue GV;
switch (CE->getOperand(0)->getType()->getTypeID()) {
default: assert(0 && "Bad add type!"); abort();
case Type::IntegerTyID:
switch (CE->getOpcode()) {
default: assert(0 && "Invalid integer opcode");
case Instruction::Add: GV.IntVal = LHS.IntVal + RHS.IntVal; break;
case Instruction::Sub: GV.IntVal = LHS.IntVal - RHS.IntVal; break;
case Instruction::Mul: GV.IntVal = LHS.IntVal * RHS.IntVal; break;
case Instruction::UDiv:GV.IntVal = LHS.IntVal.udiv(RHS.IntVal); break;
case Instruction::SDiv:GV.IntVal = LHS.IntVal.sdiv(RHS.IntVal); break;
case Instruction::URem:GV.IntVal = LHS.IntVal.urem(RHS.IntVal); break;
case Instruction::SRem:GV.IntVal = LHS.IntVal.srem(RHS.IntVal); break;
case Instruction::And: GV.IntVal = LHS.IntVal & RHS.IntVal; break;
case Instruction::Or: GV.IntVal = LHS.IntVal | RHS.IntVal; break;
case Instruction::Xor: GV.IntVal = LHS.IntVal ^ RHS.IntVal; break;
}
break;
case Type::FloatTyID:
switch (CE->getOpcode()) {
default: assert(0 && "Invalid float opcode"); abort();
case Instruction::Add:
GV.FloatVal = LHS.FloatVal + RHS.FloatVal; break;
case Instruction::Sub:
GV.FloatVal = LHS.FloatVal - RHS.FloatVal; break;
case Instruction::Mul:
GV.FloatVal = LHS.FloatVal * RHS.FloatVal; break;
case Instruction::FDiv:
GV.FloatVal = LHS.FloatVal / RHS.FloatVal; break;
case Instruction::FRem:
GV.FloatVal = ::fmodf(LHS.FloatVal,RHS.FloatVal); break;
}
break;
case Type::DoubleTyID:
switch (CE->getOpcode()) {
default: assert(0 && "Invalid double opcode"); abort();
case Instruction::Add:
GV.DoubleVal = LHS.DoubleVal + RHS.DoubleVal; break;
case Instruction::Sub:
GV.DoubleVal = LHS.DoubleVal - RHS.DoubleVal; break;
case Instruction::Mul:
GV.DoubleVal = LHS.DoubleVal * RHS.DoubleVal; break;
case Instruction::FDiv:
GV.DoubleVal = LHS.DoubleVal / RHS.DoubleVal; break;
case Instruction::FRem:
GV.DoubleVal = ::fmod(LHS.DoubleVal,RHS.DoubleVal); break;
}
break;
case Type::X86_FP80TyID:
case Type::PPC_FP128TyID:
case Type::FP128TyID: {
APFloat apfLHS = APFloat(LHS.IntVal);
switch (CE->getOpcode()) {
default: assert(0 && "Invalid long double opcode"); abort();
case Instruction::Add:
apfLHS.add(APFloat(RHS.IntVal), APFloat::rmNearestTiesToEven);
GV.IntVal = apfLHS.bitcastToAPInt();
break;
case Instruction::Sub:
apfLHS.subtract(APFloat(RHS.IntVal), APFloat::rmNearestTiesToEven);
GV.IntVal = apfLHS.bitcastToAPInt();
break;
case Instruction::Mul:
apfLHS.multiply(APFloat(RHS.IntVal), APFloat::rmNearestTiesToEven);
GV.IntVal = apfLHS.bitcastToAPInt();
break;
case Instruction::FDiv:
apfLHS.divide(APFloat(RHS.IntVal), APFloat::rmNearestTiesToEven);
GV.IntVal = apfLHS.bitcastToAPInt();
break;
case Instruction::FRem:
apfLHS.mod(APFloat(RHS.IntVal), APFloat::rmNearestTiesToEven);
GV.IntVal = apfLHS.bitcastToAPInt();
break;
}
}
break;
}
return GV;
}
default:
break;
}
cerr << "ConstantExpr not handled: " << *CE << "\n";
abort();
}
GenericValue Result;
switch (C->getType()->getTypeID()) {
case Type::FloatTyID:
Result.FloatVal = cast<ConstantFP>(C)->getValueAPF().convertToFloat();
break;
case Type::DoubleTyID:
Result.DoubleVal = cast<ConstantFP>(C)->getValueAPF().convertToDouble();
break;
case Type::X86_FP80TyID:
case Type::FP128TyID:
case Type::PPC_FP128TyID:
Result.IntVal = cast <ConstantFP>(C)->getValueAPF().bitcastToAPInt();
break;
case Type::IntegerTyID:
Result.IntVal = cast<ConstantInt>(C)->getValue();
break;
case Type::PointerTyID:
if (isa<ConstantPointerNull>(C))
Result.PointerVal = 0;
else if (const Function *F = dyn_cast<Function>(C))
Result = PTOGV(getPointerToFunctionOrStub(const_cast<Function*>(F)));
else if (const GlobalVariable* GV = dyn_cast<GlobalVariable>(C))
Result = PTOGV(getOrEmitGlobalVariable(const_cast<GlobalVariable*>(GV)));
else
assert(0 && "Unknown constant pointer type!");
break;
default:
cerr << "ERROR: Constant unimplemented for type: " << *C->getType() << "\n";
abort();
}
return Result;
}
/// \brief Fold binary operations.
///
/// The list of operations we constant fold might not be complete. Start with
/// folding the operations used by the standard library.
static SILInstruction *constantFoldBinary(BuiltinInst *BI,
BuiltinValueKind ID,
Optional<bool> &ResultsInError) {
switch (ID) {
default:
llvm_unreachable("Not all BUILTIN_BINARY_OPERATIONs are covered!");
// Not supported yet (not easily computable for APInt).
case BuiltinValueKind::ExactSDiv:
case BuiltinValueKind::ExactUDiv:
return nullptr;
// Not supported now.
case BuiltinValueKind::FRem:
return nullptr;
// Fold constant division operations and report div by zero.
case BuiltinValueKind::SDiv:
case BuiltinValueKind::SRem:
case BuiltinValueKind::UDiv:
case BuiltinValueKind::URem: {
return constantFoldAndCheckDivision(BI, ID, ResultsInError);
}
// Are there valid uses for these in stdlib?
case BuiltinValueKind::Add:
case BuiltinValueKind::Mul:
case BuiltinValueKind::Sub:
return nullptr;
case BuiltinValueKind::And:
case BuiltinValueKind::AShr:
case BuiltinValueKind::LShr:
case BuiltinValueKind::Or:
case BuiltinValueKind::Shl:
case BuiltinValueKind::Xor: {
OperandValueArrayRef Args = BI->getArguments();
auto *LHS = dyn_cast<IntegerLiteralInst>(Args[0]);
auto *RHS = dyn_cast<IntegerLiteralInst>(Args[1]);
if (!RHS || !LHS)
return nullptr;
APInt LHSI = LHS->getValue();
APInt RHSI = RHS->getValue();
bool IsShift = ID == BuiltinValueKind::AShr ||
ID == BuiltinValueKind::LShr ||
ID == BuiltinValueKind::Shl;
// Reject shifting all significant bits
if (IsShift && RHSI.getZExtValue() >= LHSI.getBitWidth()) {
diagnose(BI->getModule().getASTContext(),
RHS->getLoc().getSourceLoc(),
diag::shifting_all_significant_bits);
ResultsInError = Optional<bool>(true);
return nullptr;
}
APInt ResI = constantFoldBitOperation(LHSI, RHSI, ID);
// Add the literal instruction to represent the result.
SILBuilderWithScope B(BI);
return B.createIntegerLiteral(BI->getLoc(), BI->getType(), ResI);
}
case BuiltinValueKind::FAdd:
case BuiltinValueKind::FDiv:
case BuiltinValueKind::FMul:
case BuiltinValueKind::FSub: {
OperandValueArrayRef Args = BI->getArguments();
auto *LHS = dyn_cast<FloatLiteralInst>(Args[0]);
auto *RHS = dyn_cast<FloatLiteralInst>(Args[1]);
if (!RHS || !LHS)
return nullptr;
APFloat LHSF = LHS->getValue();
APFloat RHSF = RHS->getValue();
switch (ID) {
default: llvm_unreachable("Not all cases are covered!");
case BuiltinValueKind::FAdd:
LHSF.add(RHSF, APFloat::rmNearestTiesToEven);
break;
case BuiltinValueKind::FDiv:
LHSF.divide(RHSF, APFloat::rmNearestTiesToEven);
break;
case BuiltinValueKind::FMul:
LHSF.multiply(RHSF, APFloat::rmNearestTiesToEven);
break;
case BuiltinValueKind::FSub:
LHSF.subtract(RHSF, APFloat::rmNearestTiesToEven);
break;
}
// Add the literal instruction to represent the result.
SILBuilderWithScope B(BI);
return B.createFloatLiteral(BI->getLoc(), BI->getType(), LHSF);
}
}
}