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llvm-project/clang/lib/CodeGen/CGCall.cpp

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//===----- CGCall.h - Encapsulate calling convention details ----*- C++ -*-===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// These classes wrap the information about a call or function
// definition used to handle ABI compliancy.
//
//===----------------------------------------------------------------------===//
#include "CGCall.h"
#include "CodeGenFunction.h"
#include "CodeGenModule.h"
#include "clang/Basic/TargetInfo.h"
#include "clang/AST/Decl.h"
#include "clang/AST/DeclCXX.h"
#include "clang/AST/DeclObjC.h"
#include "clang/Frontend/CompileOptions.h"
#include "llvm/Attributes.h"
#include "llvm/Support/CallSite.h"
#include "llvm/Target/TargetData.h"
#include "ABIInfo.h"
using namespace clang;
using namespace CodeGen;
/***/
// FIXME: Use iterator and sidestep silly type array creation.
const
CGFunctionInfo &CodeGenTypes::getFunctionInfo(const FunctionNoProtoType *FTNP) {
return getFunctionInfo(FTNP->getResultType(),
llvm::SmallVector<QualType, 16>());
}
const
CGFunctionInfo &CodeGenTypes::getFunctionInfo(const FunctionProtoType *FTP) {
llvm::SmallVector<QualType, 16> ArgTys;
// FIXME: Kill copy.
for (unsigned i = 0, e = FTP->getNumArgs(); i != e; ++i)
ArgTys.push_back(FTP->getArgType(i));
return getFunctionInfo(FTP->getResultType(), ArgTys);
}
const CGFunctionInfo &CodeGenTypes::getFunctionInfo(const CXXMethodDecl *MD) {
llvm::SmallVector<QualType, 16> ArgTys;
// Add the 'this' pointer unless this is a static method.
if (MD->isInstance())
ArgTys.push_back(MD->getThisType(Context));
const FunctionProtoType *FTP = MD->getType()->getAsFunctionProtoType();
for (unsigned i = 0, e = FTP->getNumArgs(); i != e; ++i)
ArgTys.push_back(FTP->getArgType(i));
return getFunctionInfo(FTP->getResultType(), ArgTys);
}
const CGFunctionInfo &CodeGenTypes::getFunctionInfo(const FunctionDecl *FD) {
if (const CXXMethodDecl *MD = dyn_cast<CXXMethodDecl>(FD))
if (MD->isInstance())
return getFunctionInfo(MD);
const FunctionType *FTy = FD->getType()->getAsFunctionType();
if (const FunctionProtoType *FTP = dyn_cast<FunctionProtoType>(FTy))
return getFunctionInfo(FTP);
return getFunctionInfo(cast<FunctionNoProtoType>(FTy));
}
const CGFunctionInfo &CodeGenTypes::getFunctionInfo(const ObjCMethodDecl *MD) {
llvm::SmallVector<QualType, 16> ArgTys;
ArgTys.push_back(MD->getSelfDecl()->getType());
ArgTys.push_back(Context.getObjCSelType());
// FIXME: Kill copy?
for (ObjCMethodDecl::param_iterator i = MD->param_begin(),
e = MD->param_end(); i != e; ++i)
ArgTys.push_back((*i)->getType());
return getFunctionInfo(MD->getResultType(), ArgTys);
}
const CGFunctionInfo &CodeGenTypes::getFunctionInfo(QualType ResTy,
const CallArgList &Args) {
// FIXME: Kill copy.
llvm::SmallVector<QualType, 16> ArgTys;
for (CallArgList::const_iterator i = Args.begin(), e = Args.end();
i != e; ++i)
ArgTys.push_back(i->second);
return getFunctionInfo(ResTy, ArgTys);
}
const CGFunctionInfo &CodeGenTypes::getFunctionInfo(QualType ResTy,
const FunctionArgList &Args) {
// FIXME: Kill copy.
llvm::SmallVector<QualType, 16> ArgTys;
for (FunctionArgList::const_iterator i = Args.begin(), e = Args.end();
i != e; ++i)
ArgTys.push_back(i->second);
return getFunctionInfo(ResTy, ArgTys);
}
const CGFunctionInfo &CodeGenTypes::getFunctionInfo(QualType ResTy,
const llvm::SmallVector<QualType, 16> &ArgTys) {
// Lookup or create unique function info.
llvm::FoldingSetNodeID ID;
CGFunctionInfo::Profile(ID, ResTy, ArgTys.begin(), ArgTys.end());
void *InsertPos = 0;
CGFunctionInfo *FI = FunctionInfos.FindNodeOrInsertPos(ID, InsertPos);
if (FI)
return *FI;
// Construct the function info.
FI = new CGFunctionInfo(ResTy, ArgTys);
FunctionInfos.InsertNode(FI, InsertPos);
// Compute ABI information.
getABIInfo().computeInfo(*FI, getContext(), TheModule.getContext());
return *FI;
}
CGFunctionInfo::CGFunctionInfo(QualType ResTy,
const llvm::SmallVector<QualType, 16> &ArgTys) {
NumArgs = ArgTys.size();
Args = new ArgInfo[1 + NumArgs];
Args[0].type = ResTy;
for (unsigned i = 0; i < NumArgs; ++i)
Args[1 + i].type = ArgTys[i];
}
/***/
void CodeGenTypes::GetExpandedTypes(QualType Ty,
std::vector<const llvm::Type*> &ArgTys) {
const RecordType *RT = Ty->getAsStructureType();
assert(RT && "Can only expand structure types.");
const RecordDecl *RD = RT->getDecl();
assert(!RD->hasFlexibleArrayMember() &&
"Cannot expand structure with flexible array.");
for (RecordDecl::field_iterator i = RD->field_begin(), e = RD->field_end();
i != e; ++i) {
const FieldDecl *FD = *i;
assert(!FD->isBitField() &&
"Cannot expand structure with bit-field members.");
QualType FT = FD->getType();
if (CodeGenFunction::hasAggregateLLVMType(FT)) {
GetExpandedTypes(FT, ArgTys);
} else {
ArgTys.push_back(ConvertType(FT));
}
}
}
llvm::Function::arg_iterator
CodeGenFunction::ExpandTypeFromArgs(QualType Ty, LValue LV,
llvm::Function::arg_iterator AI) {
const RecordType *RT = Ty->getAsStructureType();
assert(RT && "Can only expand structure types.");
RecordDecl *RD = RT->getDecl();
assert(LV.isSimple() &&
"Unexpected non-simple lvalue during struct expansion.");
llvm::Value *Addr = LV.getAddress();
for (RecordDecl::field_iterator i = RD->field_begin(), e = RD->field_end();
i != e; ++i) {
FieldDecl *FD = *i;
QualType FT = FD->getType();
// FIXME: What are the right qualifiers here?
LValue LV = EmitLValueForField(Addr, FD, false, 0);
if (CodeGenFunction::hasAggregateLLVMType(FT)) {
AI = ExpandTypeFromArgs(FT, LV, AI);
} else {
EmitStoreThroughLValue(RValue::get(AI), LV, FT);
++AI;
}
}
return AI;
}
void
CodeGenFunction::ExpandTypeToArgs(QualType Ty, RValue RV,
llvm::SmallVector<llvm::Value*, 16> &Args) {
const RecordType *RT = Ty->getAsStructureType();
assert(RT && "Can only expand structure types.");
RecordDecl *RD = RT->getDecl();
assert(RV.isAggregate() && "Unexpected rvalue during struct expansion");
llvm::Value *Addr = RV.getAggregateAddr();
for (RecordDecl::field_iterator i = RD->field_begin(), e = RD->field_end();
i != e; ++i) {
FieldDecl *FD = *i;
QualType FT = FD->getType();
// FIXME: What are the right qualifiers here?
LValue LV = EmitLValueForField(Addr, FD, false, 0);
if (CodeGenFunction::hasAggregateLLVMType(FT)) {
ExpandTypeToArgs(FT, RValue::getAggregate(LV.getAddress()), Args);
} else {
RValue RV = EmitLoadOfLValue(LV, FT);
assert(RV.isScalar() &&
"Unexpected non-scalar rvalue during struct expansion.");
Args.push_back(RV.getScalarVal());
}
}
}
/// CreateCoercedLoad - Create a load from \arg SrcPtr interpreted as
/// a pointer to an object of type \arg Ty.
///
/// This safely handles the case when the src type is smaller than the
/// destination type; in this situation the values of bits which not
/// present in the src are undefined.
static llvm::Value *CreateCoercedLoad(llvm::Value *SrcPtr,
const llvm::Type *Ty,
CodeGenFunction &CGF) {
const llvm::Type *SrcTy =
cast<llvm::PointerType>(SrcPtr->getType())->getElementType();
uint64_t SrcSize = CGF.CGM.getTargetData().getTypeAllocSize(SrcTy);
uint64_t DstSize = CGF.CGM.getTargetData().getTypeAllocSize(Ty);
// If load is legal, just bitcast the src pointer.
if (SrcSize >= DstSize) {
// Generally SrcSize is never greater than DstSize, since this means we are
// losing bits. However, this can happen in cases where the structure has
// additional padding, for example due to a user specified alignment.
//
// FIXME: Assert that we aren't truncating non-padding bits when have access
// to that information.
llvm::Value *Casted =
CGF.Builder.CreateBitCast(SrcPtr, llvm::PointerType::getUnqual(Ty));
llvm::LoadInst *Load = CGF.Builder.CreateLoad(Casted);
// FIXME: Use better alignment / avoid requiring aligned load.
Load->setAlignment(1);
return Load;
} else {
// Otherwise do coercion through memory. This is stupid, but
// simple.
llvm::Value *Tmp = CGF.CreateTempAlloca(Ty);
llvm::Value *Casted =
CGF.Builder.CreateBitCast(Tmp, llvm::PointerType::getUnqual(SrcTy));
llvm::StoreInst *Store =
CGF.Builder.CreateStore(CGF.Builder.CreateLoad(SrcPtr), Casted);
// FIXME: Use better alignment / avoid requiring aligned store.
Store->setAlignment(1);
return CGF.Builder.CreateLoad(Tmp);
}
}
/// CreateCoercedStore - Create a store to \arg DstPtr from \arg Src,
/// where the source and destination may have different types.
///
/// This safely handles the case when the src type is larger than the
/// destination type; the upper bits of the src will be lost.
static void CreateCoercedStore(llvm::Value *Src,
llvm::Value *DstPtr,
CodeGenFunction &CGF) {
const llvm::Type *SrcTy = Src->getType();
const llvm::Type *DstTy =
cast<llvm::PointerType>(DstPtr->getType())->getElementType();
uint64_t SrcSize = CGF.CGM.getTargetData().getTypeAllocSize(SrcTy);
uint64_t DstSize = CGF.CGM.getTargetData().getTypeAllocSize(DstTy);
// If store is legal, just bitcast the src pointer.
if (SrcSize <= DstSize) {
llvm::Value *Casted =
CGF.Builder.CreateBitCast(DstPtr, llvm::PointerType::getUnqual(SrcTy));
// FIXME: Use better alignment / avoid requiring aligned store.
CGF.Builder.CreateStore(Src, Casted)->setAlignment(1);
} else {
// Otherwise do coercion through memory. This is stupid, but
// simple.
// Generally SrcSize is never greater than DstSize, since this means we are
// losing bits. However, this can happen in cases where the structure has
// additional padding, for example due to a user specified alignment.
//
// FIXME: Assert that we aren't truncating non-padding bits when have access
// to that information.
llvm::Value *Tmp = CGF.CreateTempAlloca(SrcTy);
CGF.Builder.CreateStore(Src, Tmp);
llvm::Value *Casted =
CGF.Builder.CreateBitCast(Tmp, llvm::PointerType::getUnqual(DstTy));
llvm::LoadInst *Load = CGF.Builder.CreateLoad(Casted);
// FIXME: Use better alignment / avoid requiring aligned load.
Load->setAlignment(1);
CGF.Builder.CreateStore(Load, DstPtr);
}
}
/***/
bool CodeGenModule::ReturnTypeUsesSret(const CGFunctionInfo &FI) {
return FI.getReturnInfo().isIndirect();
}
const llvm::FunctionType *
CodeGenTypes::GetFunctionType(const CGFunctionInfo &FI, bool IsVariadic) {
std::vector<const llvm::Type*> ArgTys;
const llvm::Type *ResultType = 0;
QualType RetTy = FI.getReturnType();
const ABIArgInfo &RetAI = FI.getReturnInfo();
switch (RetAI.getKind()) {
case ABIArgInfo::Expand:
assert(0 && "Invalid ABI kind for return argument");
case ABIArgInfo::Extend:
case ABIArgInfo::Direct:
ResultType = ConvertType(RetTy);
break;
case ABIArgInfo::Indirect: {
assert(!RetAI.getIndirectAlign() && "Align unused on indirect return.");
ResultType = llvm::Type::VoidTy;
const llvm::Type *STy = ConvertType(RetTy);
ArgTys.push_back(llvm::PointerType::get(STy, RetTy.getAddressSpace()));
break;
}
case ABIArgInfo::Ignore:
ResultType = llvm::Type::VoidTy;
break;
case ABIArgInfo::Coerce:
ResultType = RetAI.getCoerceToType();
break;
}
for (CGFunctionInfo::const_arg_iterator it = FI.arg_begin(),
ie = FI.arg_end(); it != ie; ++it) {
const ABIArgInfo &AI = it->info;
switch (AI.getKind()) {
case ABIArgInfo::Ignore:
break;
case ABIArgInfo::Coerce:
ArgTys.push_back(AI.getCoerceToType());
break;
case ABIArgInfo::Indirect: {
// indirect arguments are always on the stack, which is addr space #0.
const llvm::Type *LTy = ConvertTypeForMem(it->type);
ArgTys.push_back(llvm::PointerType::getUnqual(LTy));
break;
}
case ABIArgInfo::Extend:
case ABIArgInfo::Direct:
ArgTys.push_back(ConvertType(it->type));
break;
case ABIArgInfo::Expand:
GetExpandedTypes(it->type, ArgTys);
break;
}
}
return llvm::FunctionType::get(ResultType, ArgTys, IsVariadic);
}
void CodeGenModule::ConstructAttributeList(const CGFunctionInfo &FI,
const Decl *TargetDecl,
AttributeListType &PAL) {
unsigned FuncAttrs = 0;
unsigned RetAttrs = 0;
// FIXME: handle sseregparm someday...
if (TargetDecl) {
if (TargetDecl->hasAttr<NoThrowAttr>())
FuncAttrs |= llvm::Attribute::NoUnwind;
if (TargetDecl->hasAttr<NoReturnAttr>())
FuncAttrs |= llvm::Attribute::NoReturn;
if (TargetDecl->hasAttr<ConstAttr>())
FuncAttrs |= llvm::Attribute::ReadNone;
else if (TargetDecl->hasAttr<PureAttr>())
FuncAttrs |= llvm::Attribute::ReadOnly;
}
if (CompileOpts.DisableRedZone)
FuncAttrs |= llvm::Attribute::NoRedZone;
if (CompileOpts.NoImplicitFloat)
FuncAttrs |= llvm::Attribute::NoImplicitFloat;
if (Features.getStackProtectorMode() == LangOptions::SSPOn)
FuncAttrs |= llvm::Attribute::StackProtect;
else if (Features.getStackProtectorMode() == LangOptions::SSPReq)
FuncAttrs |= llvm::Attribute::StackProtectReq;
QualType RetTy = FI.getReturnType();
unsigned Index = 1;
const ABIArgInfo &RetAI = FI.getReturnInfo();
switch (RetAI.getKind()) {
case ABIArgInfo::Extend:
if (RetTy->isSignedIntegerType()) {
RetAttrs |= llvm::Attribute::SExt;
} else if (RetTy->isUnsignedIntegerType()) {
RetAttrs |= llvm::Attribute::ZExt;
}
// FALLTHROUGH
case ABIArgInfo::Direct:
break;
case ABIArgInfo::Indirect:
PAL.push_back(llvm::AttributeWithIndex::get(Index,
llvm::Attribute::StructRet |
llvm::Attribute::NoAlias));
++Index;
// sret disables readnone and readonly
FuncAttrs &= ~(llvm::Attribute::ReadOnly |
llvm::Attribute::ReadNone);
break;
case ABIArgInfo::Ignore:
case ABIArgInfo::Coerce:
break;
case ABIArgInfo::Expand:
assert(0 && "Invalid ABI kind for return argument");
}
if (RetAttrs)
PAL.push_back(llvm::AttributeWithIndex::get(0, RetAttrs));
// FIXME: we need to honour command line settings also...
// FIXME: RegParm should be reduced in case of nested functions and/or global
// register variable.
signed RegParm = 0;
if (TargetDecl)
if (const RegparmAttr *RegParmAttr
= TargetDecl->getAttr<RegparmAttr>())
RegParm = RegParmAttr->getNumParams();
unsigned PointerWidth = getContext().Target.getPointerWidth(0);
for (CGFunctionInfo::const_arg_iterator it = FI.arg_begin(),
ie = FI.arg_end(); it != ie; ++it) {
QualType ParamType = it->type;
const ABIArgInfo &AI = it->info;
unsigned Attributes = 0;
switch (AI.getKind()) {
case ABIArgInfo::Coerce:
break;
case ABIArgInfo::Indirect:
Attributes |= llvm::Attribute::ByVal;
Attributes |=
llvm::Attribute::constructAlignmentFromInt(AI.getIndirectAlign());
// byval disables readnone and readonly.
FuncAttrs &= ~(llvm::Attribute::ReadOnly |
llvm::Attribute::ReadNone);
break;
case ABIArgInfo::Extend:
if (ParamType->isSignedIntegerType()) {
Attributes |= llvm::Attribute::SExt;
} else if (ParamType->isUnsignedIntegerType()) {
Attributes |= llvm::Attribute::ZExt;
}
// FALLS THROUGH
case ABIArgInfo::Direct:
if (RegParm > 0 &&
(ParamType->isIntegerType() || ParamType->isPointerType())) {
RegParm -=
(Context.getTypeSize(ParamType) + PointerWidth - 1) / PointerWidth;
if (RegParm >= 0)
Attributes |= llvm::Attribute::InReg;
}
// FIXME: handle sseregparm someday...
break;
case ABIArgInfo::Ignore:
// Skip increment, no matching LLVM parameter.
continue;
case ABIArgInfo::Expand: {
std::vector<const llvm::Type*> Tys;
// FIXME: This is rather inefficient. Do we ever actually need to do
// anything here? The result should be just reconstructed on the other
// side, so extension should be a non-issue.
getTypes().GetExpandedTypes(ParamType, Tys);
Index += Tys.size();
continue;
}
}
if (Attributes)
PAL.push_back(llvm::AttributeWithIndex::get(Index, Attributes));
++Index;
}
if (FuncAttrs)
PAL.push_back(llvm::AttributeWithIndex::get(~0, FuncAttrs));
}
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<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.
std::string Name = Arg->getNameAsString();
llvm::Value *Temp = CreateTempAlloca(ConvertTypeForMem(Ty),
(Name + ".addr").c_str());
// FIXME: What are the right qualifiers here?
llvm::Function::arg_iterator End =
ExpandTypeFromArgs(Ty, LValue::MakeAddr(Temp,0), AI);
EmitParmDecl(*Arg, Temp);
// Name the arguments used in expansion and increment AI.
unsigned Index = 0;
for (; AI != End; ++AI, ++Index)
AI->setName(Name + "." + 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!");
}
void CodeGenFunction::EmitFunctionEpilog(const CGFunctionInfo &FI,
llvm::Value *ReturnValue) {
llvm::Value *RV = 0;
// Functions with no result always return void.
if (ReturnValue) {
QualType RetTy = FI.getReturnType();
const ABIArgInfo &RetAI = FI.getReturnInfo();
switch (RetAI.getKind()) {
case ABIArgInfo::Indirect:
if (RetTy->isAnyComplexType()) {
ComplexPairTy RT = LoadComplexFromAddr(ReturnValue, false);
StoreComplexToAddr(RT, CurFn->arg_begin(), false);
} else if (CodeGenFunction::hasAggregateLLVMType(RetTy)) {
EmitAggregateCopy(CurFn->arg_begin(), ReturnValue, RetTy);
} else {
EmitStoreOfScalar(Builder.CreateLoad(ReturnValue), CurFn->arg_begin(),
false, RetTy);
}
break;
case ABIArgInfo::Extend:
case ABIArgInfo::Direct:
// The internal return value temp always will have
// pointer-to-return-type type.
RV = Builder.CreateLoad(ReturnValue);
break;
case ABIArgInfo::Ignore:
break;
case ABIArgInfo::Coerce:
RV = CreateCoercedLoad(ReturnValue, RetAI.getCoerceToType(), *this);
break;
case ABIArgInfo::Expand:
assert(0 && "Invalid ABI kind for return argument");
}
}
if (RV) {
Builder.CreateRet(RV);
} else {
Builder.CreateRetVoid();
}
}
RValue CodeGenFunction::EmitCallArg(const Expr *E, QualType ArgType) {
if (ArgType->isReferenceType())
return EmitReferenceBindingToExpr(E, ArgType);
return EmitAnyExprToTemp(E);
}
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();
CodeGen::AttributeListType AttributeList;
CGM.ConstructAttributeList(CallInfo, TargetDecl, AttributeList);
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);
if (const llvm::Function *F =
dyn_cast<llvm::Function>(Callee->stripPointerCasts()))
CS.setCallingConv(F->getCallingConv());
// 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() != llvm::Type::VoidTy)
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);
}
/* VarArg handling */
llvm::Value *CodeGenFunction::EmitVAArg(llvm::Value *VAListAddr, QualType Ty) {
return CGM.getTypes().getABIInfo().EmitVAArg(VAListAddr, Ty, *this);
}
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