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//===---- CGBuiltin.cpp - Emit LLVM Code for builtins ---------------------===//
//
// The LLVM Compiler Infrastructure
//
// This file was developed by Anders Carlsson and is distributed under
// the University of Illinois Open Source License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This contains code to emit Builtin calls as LLVM code.
//
//===----------------------------------------------------------------------===//
#include "CodeGenFunction.h"
#include "CodeGenModule.h"
#include "clang/AST/ASTContext.h"
#include "clang/AST/Builtins.h"
#include "clang/AST/Expr.h"
#include "llvm/Constants.h"
#include "llvm/Function.h"
#include "llvm/Intrinsics.h"
using namespace clang;
using namespace CodeGen;
RValue CodeGenFunction::EmitBuiltinExpr(unsigned BuiltinID, const CallExpr *E) {
switch (BuiltinID) {
default:
if (getContext().BuiltinInfo.isLibFunction(BuiltinID))
return EmitCallExpr(CGM.getBuiltinLibFunction(BuiltinID), E);
WarnUnsupported(E, "builtin function");
// Unknown builtin, for now just dump it out and return undef.
if (hasAggregateLLVMType(E->getType()))
return RValue::getAggregate(CreateTempAlloca(ConvertType(E->getType())));
return RValue::get(llvm::UndefValue::get(ConvertType(E->getType())));
case Builtin::BI__builtin___CFStringMakeConstantString: {
const Expr *Arg = E->getArg(0);
while (1) {
if (const ParenExpr *PE = dyn_cast<ParenExpr>(Arg))
Arg = PE->getSubExpr();
else if (const ImplicitCastExpr *CE = dyn_cast<ImplicitCastExpr>(Arg))
Arg = CE->getSubExpr();
else
break;
}
const StringLiteral *Literal = cast<StringLiteral>(Arg);
std::string S(Literal->getStrData(), Literal->getByteLength());
return RValue::get(CGM.GetAddrOfConstantCFString(S));
}
case Builtin::BI__builtin_va_start:
case Builtin::BI__builtin_va_end: {
llvm::Value *ArgValue = EmitScalarExpr(E->getArg(0));
const llvm::Type *DestType = llvm::PointerType::get(llvm::Type::Int8Ty);
if (ArgValue->getType() != DestType)
ArgValue = Builder.CreateBitCast(ArgValue, DestType,
ArgValue->getNameStart());
llvm::Intrinsic::ID inst = (BuiltinID == Builtin::BI__builtin_va_start) ?
llvm::Intrinsic::vastart : llvm::Intrinsic::vaend;
llvm::Value *F = llvm::Intrinsic::getDeclaration(&CGM.getModule(), inst);
llvm::Value *V = Builder.CreateCall(F, ArgValue);
return RValue::get(V);
}
case Builtin::BI__builtin_classify_type: {
llvm::APSInt Result(32);
if (!E->isBuiltinClassifyType(Result))
assert(0 && "Expr not __builtin_classify_type!");
return RValue::get(llvm::ConstantInt::get(Result));
}
case Builtin::BI__builtin_constant_p: {
llvm::APSInt Result(32);
// FIXME: Analyze the parameter and check if it is a constant.
Result = 0;
return RValue::get(llvm::ConstantInt::get(Result));
}
case Builtin::BI__builtin_abs: {
llvm::Value *ArgValue = EmitScalarExpr(E->getArg(0));
llvm::BinaryOperator *NegOp =
Builder.CreateNeg(ArgValue, (ArgValue->getName() + "neg").c_str());
llvm::Value *CmpResult =
Builder.CreateICmpSGE(ArgValue, NegOp->getOperand(0), "abscond");
llvm::Value *Result =
Builder.CreateSelect(CmpResult, ArgValue, NegOp, "abs");
return RValue::get(Result);
}
case Builtin::BI__builtin_expect: {
llvm::Value *Condition = EmitScalarExpr(E->getArg(0));
return RValue::get(Condition);
}
}
return RValue::get(0);
}
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