path: root/lib/CodeGen/CGBuiltin.cpp

//===---- CGBuiltin.cpp - Emit LLVM Code for builtins ---------------------===//
//
//                     The LLVM Compiler Infrastructure
//
// This file 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/Basic/TargetInfo.h"
#include "clang/AST/ASTContext.h"
#include "clang/AST/Builtins.h"
#include "clang/AST/Expr.h"
#include "clang/AST/TargetBuiltins.h"
#include "llvm/Constants.h"
#include "llvm/Function.h"
#include "llvm/Intrinsics.h"
using namespace clang;
using namespace CodeGen;
using namespace llvm;

/// Utility to insert an atomic instruction based Instrinsic::ID and
// the expression node
static RValue EmitBinaryAtomic(CodeGenFunction& CFG, 
                               Intrinsic::ID Id, const CallExpr *E) {
  const llvm::Type *ResType = CFG.ConvertType(E->getType());
  Value *AtomF = CFG.CGM.getIntrinsic(Id, &ResType, 1);
  return RValue::get(CFG.Builder.CreateCall2(AtomF,
                                             CFG.EmitScalarExpr(E->getArg(0)),
                                             CFG.EmitScalarExpr(E->getArg(1))));
}

RValue CodeGenFunction::EmitBuiltinExpr(unsigned BuiltinID, const CallExpr *E) {
  switch (BuiltinID) {
  default: break;  // Handle intrinsics and libm functions below.
      
  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_stdarg_start:
  case Builtin::BI__builtin_va_start:
  case Builtin::BI__builtin_va_end: {
    Value *ArgValue = EmitScalarExpr(E->getArg(0));
    const llvm::Type *DestType = 
      llvm::PointerType::getUnqual(llvm::Type::Int8Ty);
    if (ArgValue->getType() != DestType)
      ArgValue = Builder.CreateBitCast(ArgValue, DestType, 
                                       ArgValue->getNameStart());

    Intrinsic::ID inst = (BuiltinID == Builtin::BI__builtin_va_end) ? 
      Intrinsic::vaend : Intrinsic::vastart;
    return RValue::get(Builder.CreateCall(CGM.getIntrinsic(inst), ArgValue));
  }
  case Builtin::BI__builtin_va_copy: {
    // FIXME: This does not yet handle architectures where va_list is a struct.
    Value *DstPtr = EmitScalarExpr(E->getArg(0));
    Value *SrcValue = EmitScalarExpr(E->getArg(1));
    
    Value *SrcPtr = CreateTempAlloca(SrcValue->getType(), "dst_ptr");
    
    Builder.CreateStore(SrcValue, SrcPtr, false);

    const llvm::Type *Type = 
      llvm::PointerType::getUnqual(llvm::Type::Int8Ty);

    DstPtr = Builder.CreateBitCast(DstPtr, Type);
    SrcPtr = Builder.CreateBitCast(SrcPtr, Type);
    return RValue::get(Builder.CreateCall2(CGM.getIntrinsic(Intrinsic::vacopy), 
                                           DstPtr, SrcPtr));
  }
  case Builtin::BI__builtin_classify_type: {
    APSInt Result(32);
    if (!E->isBuiltinClassifyType(Result))
      assert(0 && "Expr not __builtin_classify_type!");
    return RValue::get(ConstantInt::get(Result));
  }
  case Builtin::BI__builtin_constant_p: {
    APSInt Result(32);
    // FIXME: Analyze the parameter and check if it is a constant.
    Result = 0;
    return RValue::get(ConstantInt::get(Result));
  }
  case Builtin::BI__builtin_abs: {
    Value *ArgValue = EmitScalarExpr(E->getArg(0));   
    
    llvm::BinaryOperator *NegOp = 
      Builder.CreateNeg(ArgValue, (ArgValue->getName() + "neg").c_str());
    Value *CmpResult = 
      Builder.CreateICmpSGE(ArgValue, NegOp->getOperand(0), "abscond");
    Value *