[cfe-dev] Tentative typeid Parser/AST implementation

[Sebastian Redl]

Doug Gregor wrote:
> Hi  Sebastian,
>
> On Sun, Nov 9, 2008 at 11:00 AM, Sebastian Redl
> <sebastian.redl at getdesigned.at> wrote:
>   
>> Attached patch implements parsing and AST support for typeid. It's not
>> complete in that the type of a typeid expression is const void instead of
>> const std::type_info, but otherwise everything should be correct. However,
>> since this is my first big change of the parser and AST, I might well have
>> overlooked something.
>>     
>
> Great! Some comments follow:
>   
Thanks.
> +class CXXTypeidExpr : public Expr {
>
> Please provide documentation for this expression type, along with an
> example of C++ code where it would show up.
>   
Done.
> +public:
> +  enum OperandKind {
> +    OpType,
> +    OpExpr
> +  };
> +
> +private:
> +  OperandKind OpKind;
>
> Why not just have a single bit:
>
>   bool OperandIsExpression : 1;
>
> ?
>   
Done.
> +CXXTypeidExpr*
> +CXXTypeidExpr::CreateImpl(llvm::Deserializer& D, ASTContext& C) {
> +  QualType Ty = QualType::ReadVal(D);
> +  OperandKind OpKind = static_cast<OperandKind>(OpKind);
>
> Something isn't right here... the argument to the static_cast should
> be an integer value read from D, right?
>   
Right. Fixed while rewriting to use a single bit.
> +    if (Tok.is(tok::r_paren))
> +      RParenLoc = ConsumeParen();
> +    else
> +      MatchRHSPunctuation(tok::r_paren, LParenLoc);
>
> I believe this can just be:
>
>   RParenLoc = MatchRHSPunctuation(tok::r_paren, LParenLoc);
>
> (This happens twice in ParseCXXTypeid)
>   
I copied the code from ParseParenExpression.
Done.

Here's an updated patch. It now looks up std::type_info and fails if it 
can't find it. This means that the type of the expression is an lvalue 
of type const std::type_info, as it should be. Semantic checking is thus 
complete.

Sebastian
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