[cfe-commits] r58306 - in /cfe/trunk: include/clang/AST/Expr.h include/clang/AST/ExprCXX.h include/clang/AST/StmtNodes.def include/clang/Analysis/PathSensitive/GRExprEngine.h lib/AST/Expr.cpp lib/Analysis/GRExprEngine.cpp lib/Sema/SemaDecl.cpp li

[Doug Gregor]

On Tue, Oct 28, 2008 at 11:42 AM, Chris Lattner <clattner at apple.com> wrote:
> On Oct 28, 2008, at 8:25 AM, Doug Gregor wrote:
>>>>
>>>> +++ cfe/trunk/lib/AST/Expr.cpp Mon Oct 27 19:22:11 2008
>>>> @@ -393,6 +393,20 @@
>>>>  break;
>>>> case ParenExprClass: // C99 6.5.1p5
>>>>  return cast<ParenExpr>(this)->getSubExpr()->isLvalue(Ctx);
>>>> +  case CallExprClass: {
>>>> +    // C++ [expr.call]p10:
>>>> +    //   A function call is an lvalue if and only if the result type
>>>> +    //   is a reference.
>>>> +    QualType CalleeType
>>>> +      =
>>>> dyn_cast<CallExpr>(this)->getCallee()->IgnoreParens()->getType();
>>>> +    if (const PointerType *FnTypePtr = CalleeType->getAsPointerType())
>>>
>>> Won't this crash if dyn_cast returns null?
>>
>> Oops, it should just be cast<CallExpr>, since we know the type statically.
>
> Oh right.
>
>>> It would also be more idiomatic
>>> and claean to make 'CalleeType' be a Type* instead of a QualType, as
>>> there
>>> are no qualifiers in the result of the dyn_cast.
>>
>> ?? The thing we're getting back is a QualType.
>
> cast<T> returns a "T*" or "const T*".  It is just being implicitly converted
> to QualType here with no qualifiers.  The cast argument is converted from
> QualType to Type by simplify_type<const ::clang::QualType> at around
> Type.h:212.

This is the code we're looking at:

>> +    QualType CalleeType
>> +      = dyn_cast<CallExpr>(this)->getCallee()->IgnoreParens()->getType();

The dyn_cast<> (now a cast<>) gives us a CallExpr*, on which we
immediately call getCallee() to get an Expr*, then IgnoreParens() and
getType(), which returns a QualType.

  - Doug