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(); } }
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); }
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 CodeGenModule::ConstructAttributeList(const CGFunctionInfo &FI, const Decl *TargetDecl, AttributeListType &PAL, unsigned &CallingConv) { unsigned FuncAttrs = 0; unsigned RetAttrs = 0; CallingConv = FI.getEffectiveCallingConvention(); // 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 (TargetDecl->hasAttr<MallocAttr>()) RetAttrs |= llvm::Attribute::NoAlias; } if (CodeGenOpts.OptimizeSize) FuncAttrs |= llvm::Attribute::OptimizeForSize; if (CodeGenOpts.DisableRedZone) FuncAttrs |= llvm::Attribute::NoRedZone; if (CodeGenOpts.NoImplicitFloat) FuncAttrs |= llvm::Attribute::NoImplicitFloat; 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: if (AI.getIndirectByVal()) 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)); }