RValue CodeGenFunction::EmitCall(const CGFunctionInfo &CallInfo,
llvm::Value *Callee,
const CallArgList &CallArgs,
const Decl *TargetDecl) {
// FIXME: We no longer need the types from CallArgs; lift up and simplify.
llvm::SmallVector<llvm::Value*, 16> Args;
// Handle struct-return functions by passing a pointer to the
// location that we would like to return into.
QualType RetTy = CallInfo.getReturnType();
const ABIArgInfo &RetAI = CallInfo.getReturnInfo();
// If the call returns a temporary with struct return, create a temporary
// alloca to hold the result.
if (CGM.ReturnTypeUsesSret(CallInfo))
Args.push_back(CreateTempAlloca(ConvertTypeForMem(RetTy)));
assert(CallInfo.arg_size() == CallArgs.size() &&
"Mismatch between function signature & arguments.");
CGFunctionInfo::const_arg_iterator info_it = CallInfo.arg_begin();
for (CallArgList::const_iterator I = CallArgs.begin(), E = CallArgs.end();
I != E; ++I, ++info_it) {
const ABIArgInfo &ArgInfo = info_it->info;
RValue RV = I->first;
switch (ArgInfo.getKind()) {
case ABIArgInfo::Indirect:
if (RV.isScalar() || RV.isComplex()) {
// Make a temporary alloca to pass the argument.
Args.push_back(CreateTempAlloca(ConvertTypeForMem(I->second)));
if (RV.isScalar())
EmitStoreOfScalar(RV.getScalarVal(), Args.back(), false, I->second);
else
StoreComplexToAddr(RV.getComplexVal(), Args.back(), false);
} else {
Args.push_back(RV.getAggregateAddr());
}
break;
case ABIArgInfo::Extend:
case ABIArgInfo::Direct:
if (RV.isScalar()) {
Args.push_back(RV.getScalarVal());
} else if (RV.isComplex()) {
llvm::Value *Tmp = llvm::UndefValue::get(ConvertType(I->second));
Tmp = Builder.CreateInsertValue(Tmp, RV.getComplexVal().first, 0);
Tmp = Builder.CreateInsertValue(Tmp, RV.getComplexVal().second, 1);
Args.push_back(Tmp);
} else {
Args.push_back(Builder.CreateLoad(RV.getAggregateAddr()));
}
break;
case ABIArgInfo::Ignore:
break;
case ABIArgInfo::Coerce: {
// FIXME: Avoid the conversion through memory if possible.
llvm::Value *SrcPtr;
if (RV.isScalar()) {
SrcPtr = CreateTempAlloca(ConvertTypeForMem(I->second), "coerce");
EmitStoreOfScalar(RV.getScalarVal(), SrcPtr, false, I->second);
} else if (RV.isComplex()) {
SrcPtr = CreateTempAlloca(ConvertTypeForMem(I->second), "coerce");
StoreComplexToAddr(RV.getComplexVal(), SrcPtr, false);
} else
SrcPtr = RV.getAggregateAddr();
Args.push_back(CreateCoercedLoad(SrcPtr, ArgInfo.getCoerceToType(),
*this));
break;
}
case ABIArgInfo::Expand:
ExpandTypeToArgs(I->second, RV, Args);
break;
}
}
// If the callee is a bitcast of a function to a varargs pointer to function
// type, check to see if we can remove the bitcast. This handles some cases
// with unprototyped functions.
if (llvm::ConstantExpr *CE = dyn_cast<llvm::ConstantExpr>(Callee))
if (llvm::Function *CalleeF = dyn_cast<llvm::Function>(CE->getOperand(0))) {
const llvm::PointerType *CurPT=cast<llvm::PointerType>(Callee->getType());
const llvm::FunctionType *CurFT =
cast<llvm::FunctionType>(CurPT->getElementType());
const llvm::FunctionType *ActualFT = CalleeF->getFunctionType();
if (CE->getOpcode() == llvm::Instruction::BitCast &&
ActualFT->getReturnType() == CurFT->getReturnType() &&
ActualFT->getNumParams() == CurFT->getNumParams() &&
ActualFT->getNumParams() == Args.size()) {
bool ArgsMatch = true;
for (unsigned i = 0, e = ActualFT->getNumParams(); i != e; ++i)
if (ActualFT->getParamType(i) != CurFT->getParamType(i)) {
ArgsMatch = false;
break;
}
// Strip the cast if we can get away with it. This is a nice cleanup,
// but also allows us to inline the function at -O0 if it is marked
// always_inline.
if (ArgsMatch)
Callee = CalleeF;
}
}
llvm::BasicBlock *InvokeDest = getInvokeDest();
unsigned CallingConv;
CodeGen::AttributeListType AttributeList;
CGM.ConstructAttributeList(CallInfo, TargetDecl, AttributeList, CallingConv);
llvm::AttrListPtr Attrs = llvm::AttrListPtr::get(AttributeList.begin(),
AttributeList.end());
llvm::CallSite CS;
if (!InvokeDest || (Attrs.getFnAttributes() & llvm::Attribute::NoUnwind)) {
CS = Builder.CreateCall(Callee, Args.data(), Args.data()+Args.size());
} else {
llvm::BasicBlock *Cont = createBasicBlock("invoke.cont");
CS = Builder.CreateInvoke(Callee, Cont, InvokeDest,
Args.data(), Args.data()+Args.size());
EmitBlock(Cont);
}
CS.setAttributes(Attrs);
CS.setCallingConv(static_cast<llvm::CallingConv::ID>(CallingConv));
// If the call doesn't return, finish the basic block and clear the
// insertion point; this allows the rest of IRgen to discard
// unreachable code.
if (CS.doesNotReturn()) {
Builder.CreateUnreachable();
Builder.ClearInsertionPoint();
// FIXME: For now, emit a dummy basic block because expr emitters in
// generally are not ready to handle emitting expressions at unreachable
// points.
EnsureInsertPoint();
// Return a reasonable RValue.
return GetUndefRValue(RetTy);
}
llvm::Instruction *CI = CS.getInstruction();
if (Builder.isNamePreserving() && !CI->getType()->isVoidTy())
CI->setName("call");
switch (RetAI.getKind()) {
case ABIArgInfo::Indirect:
if (RetTy->isAnyComplexType())
return RValue::getComplex(LoadComplexFromAddr(Args[0], false));
if (CodeGenFunction::hasAggregateLLVMType(RetTy))
return RValue::getAggregate(Args[0]);
return RValue::get(EmitLoadOfScalar(Args[0], false, RetTy));
case ABIArgInfo::Extend:
case ABIArgInfo::Direct:
if (RetTy->isAnyComplexType()) {
llvm::Value *Real = Builder.CreateExtractValue(CI, 0);
llvm::Value *Imag = Builder.CreateExtractValue(CI, 1);
return RValue::getComplex(std::make_pair(Real, Imag));
}
if (CodeGenFunction::hasAggregateLLVMType(RetTy)) {
llvm::Value *V = CreateTempAlloca(ConvertTypeForMem(RetTy), "agg.tmp");
Builder.CreateStore(CI, V);
return RValue::getAggregate(V);
}
return RValue::get(CI);
case ABIArgInfo::Ignore:
// If we are ignoring an argument that had a result, make sure to
// construct the appropriate return value for our caller.
return GetUndefRValue(RetTy);
case ABIArgInfo::Coerce: {
// FIXME: Avoid the conversion through memory if possible.
llvm::Value *V = CreateTempAlloca(ConvertTypeForMem(RetTy), "coerce");
CreateCoercedStore(CI, V, *this);
if (RetTy->isAnyComplexType())
return RValue::getComplex(LoadComplexFromAddr(V, false));
if (CodeGenFunction::hasAggregateLLVMType(RetTy))
return RValue::getAggregate(V);
return RValue::get(EmitLoadOfScalar(V, false, RetTy));
}
case ABIArgInfo::Expand:
assert(0 && "Invalid ABI kind for return argument");
}
assert(0 && "Unhandled ABIArgInfo::Kind");
return RValue::get(0);
}
void CodeGenFunction::GenerateThunk(llvm::Function *Fn,
const CGFunctionInfo &FnInfo,
GlobalDecl GD, const ThunkInfo &Thunk) {
const CXXMethodDecl *MD = cast<CXXMethodDecl>(GD.getDecl());
const FunctionProtoType *FPT = MD->getType()->getAs<FunctionProtoType>();
QualType ResultType = FPT->getResultType();
QualType ThisType = MD->getThisType(getContext());
FunctionArgList FunctionArgs;
// FIXME: It would be nice if more of this code could be shared with
// CodeGenFunction::GenerateCode.
// Create the implicit 'this' parameter declaration.
CurGD = GD;
CGM.getCXXABI().BuildInstanceFunctionParams(*this, ResultType, FunctionArgs);
// Add the rest of the parameters.
for (FunctionDecl::param_const_iterator I = MD->param_begin(),
E = MD->param_end(); I != E; ++I) {
ParmVarDecl *Param = *I;
FunctionArgs.push_back(Param);
}
StartFunction(GlobalDecl(), ResultType, Fn, FnInfo, FunctionArgs,
SourceLocation());
CGM.getCXXABI().EmitInstanceFunctionProlog(*this);
CXXThisValue = CXXABIThisValue;
// Adjust the 'this' pointer if necessary.
llvm::Value *AdjustedThisPtr =
PerformTypeAdjustment(*this, LoadCXXThis(),
Thunk.This.NonVirtual,
Thunk.This.VCallOffsetOffset,
/*IsReturnAdjustment*/false);
CallArgList CallArgs;
// Add our adjusted 'this' pointer.
CallArgs.add(RValue::get(AdjustedThisPtr), ThisType);
// Add the rest of the parameters.
for (FunctionDecl::param_const_iterator I = MD->param_begin(),
E = MD->param_end(); I != E; ++I) {
ParmVarDecl *param = *I;
EmitDelegateCallArg(CallArgs, param);
}
// Get our callee.
llvm::Type *Ty =
CGM.getTypes().GetFunctionType(CGM.getTypes().arrangeGlobalDeclaration(GD));
llvm::Value *Callee = CGM.GetAddrOfFunction(GD, Ty, /*ForVTable=*/true);
#ifndef NDEBUG
const CGFunctionInfo &CallFnInfo =
CGM.getTypes().arrangeCXXMethodCall(CallArgs, FPT,
RequiredArgs::forPrototypePlus(FPT, 1));
assert(CallFnInfo.getRegParm() == FnInfo.getRegParm() &&
CallFnInfo.isNoReturn() == FnInfo.isNoReturn() &&
CallFnInfo.getCallingConvention() == FnInfo.getCallingConvention());
assert(isa<CXXDestructorDecl>(MD) || // ignore dtor return types
similar(CallFnInfo.getReturnInfo(), CallFnInfo.getReturnType(),
FnInfo.getReturnInfo(), FnInfo.getReturnType()));
assert(CallFnInfo.arg_size() == FnInfo.arg_size());
for (unsigned i = 0, e = FnInfo.arg_size(); i != e; ++i)
assert(similar(CallFnInfo.arg_begin()[i].info,
CallFnInfo.arg_begin()[i].type,
FnInfo.arg_begin()[i].info, FnInfo.arg_begin()[i].type));
#endif
// Determine whether we have a return value slot to use.
ReturnValueSlot Slot;
if (!ResultType->isVoidType() &&
FnInfo.getReturnInfo().getKind() == ABIArgInfo::Indirect &&
hasAggregateLLVMType(CurFnInfo->getReturnType()))
Slot = ReturnValueSlot(ReturnValue, ResultType.isVolatileQualified());
// Now emit our call.
RValue RV = EmitCall(FnInfo, Callee, Slot, CallArgs, MD);
if (!Thunk.Return.isEmpty())
RV = PerformReturnAdjustment(*this, ResultType, RV, Thunk);
if (!ResultType->isVoidType() && Slot.isNull())
CGM.getCXXABI().EmitReturnFromThunk(*this, RV, ResultType);
// Disable the final ARC autorelease.
AutoreleaseResult = false;
FinishFunction();
// Set the right linkage.
CGM.setFunctionLinkage(MD, Fn);
// Set the right visibility.
setThunkVisibility(CGM, MD, Thunk, Fn);
}
void CodeGenFunction::EmitFunctionProlog(const CGFunctionInfo &FI,
llvm::Function *Fn,
const FunctionArgList &Args) {
// If this is an implicit-return-zero function, go ahead and
// initialize the return value. TODO: it might be nice to have
// a more general mechanism for this that didn't require synthesized
// return statements.
if (const FunctionDecl* FD = dyn_cast_or_null<FunctionDecl>(CurFuncDecl)) {
if (FD->hasImplicitReturnZero()) {
QualType RetTy = FD->getResultType().getUnqualifiedType();
const llvm::Type* LLVMTy = CGM.getTypes().ConvertType(RetTy);
llvm::Constant* Zero = llvm::Constant::getNullValue(LLVMTy);
Builder.CreateStore(Zero, ReturnValue);
}
}
// FIXME: We no longer need the types from FunctionArgList; lift up and
// simplify.
// Emit allocs for param decls. Give the LLVM Argument nodes names.
llvm::Function::arg_iterator AI = Fn->arg_begin();
// Name the struct return argument.
if (CGM.ReturnTypeUsesSret(FI)) {
AI->setName("agg.result");
++AI;
}
assert(FI.arg_size() == Args.size() &&
"Mismatch between function signature & arguments.");
CGFunctionInfo::const_arg_iterator info_it = FI.arg_begin();
for (FunctionArgList::const_iterator i = Args.begin(), e = Args.end();
i != e; ++i, ++info_it) {
const VarDecl *Arg = i->first;
QualType Ty = info_it->type;
const ABIArgInfo &ArgI = info_it->info;
switch (ArgI.getKind()) {
case ABIArgInfo::Indirect: {
llvm::Value* V = AI;
if (hasAggregateLLVMType(Ty)) {
// Do nothing, aggregates and complex variables are accessed by
// reference.
} else {
// Load scalar value from indirect argument.
V = EmitLoadOfScalar(V, false, Ty);
if (!getContext().typesAreCompatible(Ty, Arg->getType())) {
// This must be a promotion, for something like
// "void a(x) short x; {..."
V = EmitScalarConversion(V, Ty, Arg->getType());
}
}
EmitParmDecl(*Arg, V);
break;
}
case ABIArgInfo::Extend:
case ABIArgInfo::Direct: {
assert(AI != Fn->arg_end() && "Argument mismatch!");
llvm::Value* V = AI;
if (hasAggregateLLVMType(Ty)) {
// Create a temporary alloca to hold the argument; the rest of
// codegen expects to access aggregates & complex values by
// reference.
V = CreateTempAlloca(ConvertTypeForMem(Ty));
Builder.CreateStore(AI, V);
} else {
if (!getContext().typesAreCompatible(Ty, Arg->getType())) {
// This must be a promotion, for something like
// "void a(x) short x; {..."
V = EmitScalarConversion(V, Ty, Arg->getType());
}
}
EmitParmDecl(*Arg, V);
break;
}
case ABIArgInfo::Expand: {
// If this structure was expanded into multiple arguments then
// we need to create a temporary and reconstruct it from the
// arguments.
llvm::Value *Temp = CreateTempAlloca(ConvertTypeForMem(Ty),
Arg->getName() + ".addr");
// FIXME: What are the right qualifiers here?
llvm::Function::arg_iterator End =
ExpandTypeFromArgs(Ty, LValue::MakeAddr(Temp, Qualifiers()), AI);
EmitParmDecl(*Arg, Temp);
// Name the arguments used in expansion and increment AI.
unsigned Index = 0;
for (; AI != End; ++AI, ++Index)
AI->setName(Arg->getName() + "." + llvm::Twine(Index));
continue;
}
case ABIArgInfo::Ignore:
// Initialize the local variable appropriately.
if (hasAggregateLLVMType(Ty)) {
EmitParmDecl(*Arg, CreateTempAlloca(ConvertTypeForMem(Ty)));
} else {
EmitParmDecl(*Arg, llvm::UndefValue::get(ConvertType(Arg->getType())));
}
// Skip increment, no matching LLVM parameter.
continue;
case ABIArgInfo::Coerce: {
assert(AI != Fn->arg_end() && "Argument mismatch!");
// FIXME: This is very wasteful; EmitParmDecl is just going to drop the
// result in a new alloca anyway, so we could just store into that
// directly if we broke the abstraction down more.
llvm::Value *V = CreateTempAlloca(ConvertTypeForMem(Ty), "coerce");
CreateCoercedStore(AI, V, *this);
// Match to what EmitParmDecl is expecting for this type.
if (!CodeGenFunction::hasAggregateLLVMType(Ty)) {
V = EmitLoadOfScalar(V, false, Ty);
if (!getContext().typesAreCompatible(Ty, Arg->getType())) {
// This must be a promotion, for something like
// "void a(x) short x; {..."
V = EmitScalarConversion(V, Ty, Arg->getType());
}
}
EmitParmDecl(*Arg, V);
break;
}
}
++AI;
}
assert(AI == Fn->arg_end() && "Argument mismatch!");
}
