[cfe-dev] Proposal to fix issue 7715

[Manuel Klimek]

Hi Doug,

sorry for the delay, I relocated to Mountain View in the meantime :) I
applied your suggestions, added a regression test case and updated the
comments.

Cheers,
/Manuel

On Mon, Sep 27, 2010 at 11:02 AM, Douglas Gregor <dgregor at apple.com> wrote:
>
> On Sep 22, 2010, at 10:08 AM, Manuel Klimek wrote:
>
>> On Mon, Sep 20, 2010 at 8:28 PM, Douglas Gregor <dgregor at apple.com> wrote:
>>>
>>> On Sep 14, 2010, at 7:39 AM, Manuel Klimek wrote:
>>>
>>>> Hi,
>>>>
>>>> I came up with a solution to http://llvm.org/bugs/show_bug.cgi?id=7715
>>>> (clang++ gives wrong error about default argument in kdatetime.h), as
>>>> talked about on IRC. It was a little more complicated than
>>>> anticipated, as we need to keep the stack of scopes correct.
>>>>
>>>> I would like to get some feedback on the general direction /
>>>> implementation of this patch. If we agree this is the way to go, I'd
>>>> comment it more thoroughly and add some more regression tests.
>>>
>>> I like the general direction; there are a few comments below. Obviously, more comments and regression tests would be greatly appreciated!
>>>
>>>> I tried
>>>> to keep the diff as small as possible, but my gut feeling would also
>>>> lead me to put more stuff into the classes as opposed to having
>>>> everything as methods on Parser. Not sure though.
>>>
>>> I'd rather keep the parsing and Sema-invoking code in the parser itself, although I admit it's mostly an aesthetic argument and it's not a strong preference.
>>
>> I trust your gut-feeling then ;)
>>
>>> A few small comments:
>>>
>>> diff --git a/include/clang/Parse/Parser.h b/include/clang/Parse/Parser.h
>>> index a7dab1e..422adce 100644
>>> --- a/include/clang/Parse/Parser.h
>>> +++ b/include/clang/Parse/Parser.h
>>> @@ -552,7 +552,30 @@ private:
>>>   //===--------------------------------------------------------------------===//
>>>   // Lexing and parsing of C++ inline methods.
>>>
>>> -  struct LexedMethod {
>>> +  struct ParsingClass;
>>> +
>>> +  class LateParsedDeclaration {
>>> +  public:
>>> +    virtual ~LateParsedDeclaration();
>>> +    virtual void ParseLexedDefaultArguments();
>>> +    virtual void ParseLexedMethodDefs();
>>> +  };
>>>
>>> I think the name ParseLexedDefaultArguments() is misleading, because default arguments aren't the only kind of thing that is delayed. C++ [class.mem]p1 also mentions function bodies (which we handle separately) and exception-specifications (which we don't handle)... the latter is why I'd prefer to keep a more generic name like "ParseLexedMethodDeclarations()".
>>
>> While trying to comment that part I got pretty confused by what you
>> write. In the C++ standard I didn't find anything in [class.mem]p1
>> that mentions function bodies (am I reading the wrong version?), but I
>> find that in [class.mem]p2 it talks about "function bodies, default
>> arguments and constructor ctor-initializers", where I'd expect
>> ctor-initializers to be basically handled the same as function bodies.
>> Where do exception specifications fall into all this?
>
> I was looking at the latest draft for the C++0x standard, where the contents of the C++98/03 [class.mem]p2 have moved into C++0x [class.mem]p1, and it now explicitly mentions exception-specifications as well as function bodies, default arguments, and (the C++0x extension) initializers for non-static data members.
>
>> I called the methods ParseLexedDefaultArguments and
>> ParseLexedMethodDefs as the function bodies must be parsed in a phase
>> after all default arguments were parsed, since as far as I understand
>> it the default arguments can always be used in the function bodies.
>> I'd assume that anything else would be basically handled in a
>> different phase, too.
>
> I was thinking that exception-specifications could be handled at the same time as default arguments, so that we do the initialization in source order.
>
>> The interface is called LateParsedDeclaration (perhaps wanting a
>> better name), as all the late parsed stuff is always combined with a
>> method declaration, as far as I understood it.
>
> Eventually, we'll have non-static data member initializers, but for now it's just method declarations.
>
>        - Doug
>
>



-- 
Manuel Klimek (http://go/klimek)
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