C++ CodeGenFunction::EmitLValue方法代码示例

static void EmitOMPAtomicReadExpr(CodeGenFunction &CGF, bool IsSeqCst,
                                  const Expr *X, const Expr *V,
                                  SourceLocation Loc) {
  // v = x;
  assert(V->isLValue() && "V of 'omp atomic read' is not lvalue");
  assert(X->isLValue() && "X of 'omp atomic read' is not lvalue");
  LValue XLValue = CGF.EmitLValue(X);
  LValue VLValue = CGF.EmitLValue(V);
  RValue Res = XLValue.isGlobalReg() ? CGF.EmitLoadOfLValue(XLValue, Loc)
                                     : CGF.EmitAtomicLoad(XLValue, Loc);
  // OpenMP, 2.12.6, atomic Construct
  // Any atomic construct with a seq_cst clause forces the atomically
  // performed operation to include an implicit flush operation without a
  // list.
  if (IsSeqCst)
    CGF.CGM.getOpenMPRuntime().EmitOMPFlush(CGF, llvm::None, Loc);
  switch (CGF.getEvaluationKind(V->getType())) {
  case TEK_Scalar:
    CGF.EmitStoreOfScalar(
        convertToScalarValue(CGF, Res, X->getType(), V->getType()), VLValue);
    break;
  case TEK_Complex:
    CGF.EmitStoreOfComplex(
        convertToComplexValue(CGF, Res, X->getType(), V->getType()), VLValue,
        /*isInit=*/false);
    break;
  case TEK_Aggregate:
    llvm_unreachable("Must be a scalar or complex.");
  }
}

// CopyObject - Utility to copy an object.  Calls copy constructor as necessary.
// DestPtr is casted to the right type.
static void CopyObject(CodeGenFunction &CGF, const Expr *E, 
                       llvm::Value *DestPtr, llvm::Value *ExceptionPtrPtr) {
  QualType ObjectType = E->getType();

  // Store the throw exception in the exception object.
  if (!CGF.hasAggregateLLVMType(ObjectType)) {
    llvm::Value *Value = CGF.EmitScalarExpr(E);
    const llvm::Type *ValuePtrTy = Value->getType()->getPointerTo();

    CGF.Builder.CreateStore(Value, 
                            CGF.Builder.CreateBitCast(DestPtr, ValuePtrTy));
  } else {
    const llvm::Type *Ty = CGF.ConvertType(ObjectType)->getPointerTo();
    const CXXRecordDecl *RD =
      cast<CXXRecordDecl>(ObjectType->getAs<RecordType>()->getDecl());
    
    llvm::Value *This = CGF.Builder.CreateBitCast(DestPtr, Ty);
    if (RD->hasTrivialCopyConstructor()) {
      CGF.EmitAggExpr(E, This, false);
    } else if (CXXConstructorDecl *CopyCtor
               = RD->getCopyConstructor(CGF.getContext(), 0)) {
      llvm::BasicBlock *PrevLandingPad = CGF.getInvokeDest();
      if (CGF.Exceptions) {
        CodeGenFunction::EHCleanupBlock Cleanup(CGF);
        llvm::Constant *FreeExceptionFn = getFreeExceptionFn(CGF);
        
        // Load the exception pointer.
        llvm::Value *ExceptionPtr = CGF.Builder.CreateLoad(ExceptionPtrPtr);
        CGF.Builder.CreateCall(FreeExceptionFn, ExceptionPtr);
      }

      llvm::Value *Src = CGF.EmitLValue(E).getAddress();
      CGF.setInvokeDest(PrevLandingPad);

      llvm::BasicBlock *TerminateHandler = CGF.getTerminateHandler();
      PrevLandingPad = CGF.getInvokeDest();
      CGF.setInvokeDest(TerminateHandler);

      // Stolen from EmitClassAggrMemberwiseCopy
      llvm::Value *Callee = CGF.CGM.GetAddrOfCXXConstructor(CopyCtor,
                                                            Ctor_Complete);
      CallArgList CallArgs;
      CallArgs.push_back(std::make_pair(RValue::get(This),
                                      CopyCtor->getThisType(CGF.getContext())));

      // Push the Src ptr.
      CallArgs.push_back(std::make_pair(RValue::get(Src),
                                        CopyCtor->getParamDecl(0)->getType()));
      QualType ResultType =
        CopyCtor->getType()->getAs<FunctionType>()->getResultType();
      CGF.EmitCall(CGF.CGM.getTypes().getFunctionInfo(ResultType, CallArgs),
                   Callee, CallArgs, CopyCtor);
      CGF.setInvokeDest(PrevLandingPad);
    } else
      llvm_unreachable("uncopyable object");
  }
}

/// \brief Emit a helper variable and return corresponding lvalue.
static LValue EmitOMPHelperVar(CodeGenFunction &CGF,
                               const DeclRefExpr *Helper) {
  auto VDecl = cast<VarDecl>(Helper->getDecl());
  CGF.EmitVarDecl(*VDecl);
  return CGF.EmitLValue(Helper);
}