[cfe-commits] [PATCH] Array exception type decay to pointer automatically

[WenHan Gu (谷汶翰)]

Hello! Revision 4 uploaded.
http://llvm.org/bugs/attachment.cgi?id=9603&action=diff

2012/11/28 Richard Smith <richard at metafoo.co.uk>

> On Tue, Nov 27, 2012 at 11:29 PM, WenHan Gu (谷汶翰) <wenhan.gu at gmail.com>wrote:
>
>> Wrong file, sorry.
>> http://llvm.org/bugs/attachment.cgi?id=9602&action=diff
>>
>
> Thanks!
>
> +/// @param[in,out] T  It will be decayed to a pointer automatically when
> input
>
> Please use \param, not @param, to match the prevailing style in Clang.
>
>    // C++ 15.4p2: A type denoted in an exception-specification shall not
> denote
>    //   an incomplete type.
> -  if (RequireCompleteType(Range.getBegin(), T,
> +  if (!T->isArrayType() && !T->isFunctionType() &&
> +      RequireCompleteType(Range.getBegin(), T,
>                            diag::err_incomplete_in_exception_spec,
>                            /*direct*/0, Range))
>      return true;
>
> +  if (T->isArrayType())
> +    T = Context.getArrayDecayedType(T);
> +  else if (T->isFunctionType())
> +    T = Context.getPointerType(T);
>
> Maybe move this before the RequireCompleteType call, and make the
> RequireCompleteType the 'else' for these? It'd also be nice to reference
> the relevant paragraph in the standard here.
>

Yes!


>
> --- a/test/SemaCXX/exception-spec-decay.cpp
> +++ a/test/SemaCXX/exception-spec-decay.cpp
> @@ -0,0 +1,33 @@
> +// RUN: %clang -x c++ -fexceptions -emit-llvm -S -o - %s | FileCheck %s
>
> Please put this test in test/CodeGenCXX/, use %clang_cc1, and specify a
> -triple.
>
> +    // CHECK-next: _ZTIPi
>
> Use "CHECK-NEXT:". FileCheck will ignore this line.
>
> A -fsyntax-only test would be useful. Something like:
>

I think checking mangled type string is more clear. Isn't it?
Therefore, I move it into CodeGenCXX. Thanks!


>
> void f() throw(int*, int());
> void f() throw(int[], int(*)());
>
> Thanks.
>>
>> 2012/11/28 WenHan Gu (谷汶翰) <wenhan.gu at gmail.com>
>>
>> Hi Richard,
>>>
>>> I've revised it again. I think this time all similar cases can run.
>>> Please have a look.
>>> http://llvm.org/bugs/attachment.cgi?id=9601&action=diff
>>> PR14388: http://llvm.org/bugs/show_bug.cgi?id=14388
>>>
>>> Thanks!
>>>
>>>
>>> 2012/11/22 Richard Smith <richard at metafoo.co.uk>
>>>
>>>> Hi,
>>>>
>>>> On Wed, Nov 21, 2012 at 11:58 PM, WenHan Gu (谷汶翰) <wenhan.gu at gmail.com>
>>>> wrote:
>>>> > Hi Richard,
>>>> >
>>>> > You're right. I've revised the patch.
>>>> > Patch url: http://llvm.org/bugs/attachment.cgi?id=9583
>>>> > (Sorry that my environment cannot upload it to GMail)
>>>> >
>>>> > I didn't put the logic inside CheckSpecifiedExceptionType, since the
>>>> > QualType is pass-by-value, instead, I found I should put it before it.
>>>> > I also made a test case.
>>>>
>>>> This still needs changes to handle the template instantiation case
>>>> (the other caller of CheckSpecifiedExceptionType):
>>>>
>>>> template<typename T> struct S {
>>>>   void f() throw(T);
>>>> };
>>>> S<int[10]> s;
>>>>
>>>> > 2012/11/21 Richard Smith <richard at metafoo.co.uk>
>>>> >>
>>>> >> On Tue, Nov 20, 2012 at 7:20 PM, WenHan Gu (谷汶翰) <
>>>> wenhan.gu at gmail.com>
>>>> >> wrote:
>>>> >> > Hi Richard,
>>>> >> > Thanks your comments.
>>>> >> >
>>>> >> > However, I have no idea whether I should do this patch.
>>>> >> > I've tested by gcc, clang and searched C++ spec draft n3242, the
>>>> result
>>>> >> > is
>>>> >> > that both GCC and Clang failed on that and I cannot find any
>>>> wording on
>>>> >> > this
>>>> >> > issue.
>>>> >>
>>>> >> I suggest you switch to using n3485.
>>>> >>
>>>> >> 15.4/2:
>>>> >>
>>>> >> A type denoted in an exception-specification shall not denote an
>>>> >> incomplete type other than a class
>>>> >> currently being defined or an rvalue reference type. A type denoted
>>>> in
>>>> >> an exception-specification shall not
>>>> >> denote a pointer or reference to an incomplete type, other than cv
>>>> >> void* or a pointer or reference to a
>>>> >> class currently being defined. A type cv T, “array of T”, or
>>>> “function
>>>> >> returning T” denoted in an exception-
>>>> >> specification is adjusted to type T, “pointer to T”, or “pointer to
>>>> >> function returning T”, respectively.
>>>> >>
>>>> >> We are supposed to apply the decay from S[10] to S* before we check
>>>> >> whether it's an incomplete-or-being-defined type or a pointer to an
>>>> >> incomplete-or-being-defined type, so S[10] is OK.
>>>> >>
>>>> >> > Could you teach me more or could some else help?
>>>> >> > Thanks!
>>>> >> >
>>>> >> >   1 struct S {
>>>> >> >   2   void foo() throw (S[10])  { throw 0; }  // Both gcc and clang
>>>> >> > failed
>>>> >> > on this function
>>>> >> >   3   void bar() throw (S)  { throw 0; }
>>>> >> >   4 };
>>>> >> >   5
>>>> >> >   6 int main() {
>>>> >> >   7   S().foo();
>>>> >> >   8   S().bar();
>>>> >> >   9 }
>>>> >> >
>>>> >> >
>>>> >> >
>>>> >> >
>>>> >> > 2012/11/21 Richard Smith <richard at metafoo.co.uk>
>>>> >> >>
>>>> >> >> Hi,
>>>> >> >>
>>>> >> >> On Tue, Nov 20, 2012 at 1:54 AM, WenHan Gu (谷汶翰) <
>>>> wenhan.gu at gmail.com>
>>>> >> >> wrote:
>>>> >> >> > Hi all,
>>>> >> >> >
>>>> >> >> > I've done the patch and testcase to fix PR14338.
>>>> >> >> > http://llvm.org/bugs/show_bug.cgi?id=14388
>>>> >> >> >
>>>> >> >> > Here's the patch, please review:
>>>> >> >> > http://llvm.org/bugs/attachment.cgi?id=9574&action=diff
>>>> >> >> >
>>>> >> >> >
>>>> >> >> > Is that okay to commit?
>>>> >> >>
>>>> >> >> A matching update is needed in SemaTemplateInstantiateDecl.
>>>> Perhaps
>>>> >> >> you could put this logic into CheckSepcifiedExceptionType (and
>>>> either
>>>> >> >> return the modified type or pass it through by reference)? One of
>>>> the
>>>> >> >> checks in  CheckSpecifiedExceptionType also needs updating. With
>>>> your
>>>> >> >> patch, we still reject this:
>>>> >> >>
>>>> >> >> struct S {
>>>> >> >>   void f() throw (S[10]);
>>>> >> >> };
>>>> >> >>
>>>> >> >> ... but we should accept it, because the type 'S' is supposed to
>>>> be
>>>> >> >> considered as complete in exception specifications inside its
>>>> body.
>>>> >> >
>>>> >> >
>>>> >> >
>>>> >> >
>>>> >> > --
>>>> >> > Best regards,
>>>> >> > Wen-Han Gu (Nowar)
>>>> >> >
>>>> >
>>>> >
>>>> >
>>>> >
>>>> > --
>>>> > Best regards,
>>>> > Wen-Han Gu (Nowar)
>>>> >
>>>>
>>>
>>>
>>>
>>> --
>>> Best regards,
>>> Wen-Han Gu (Nowar)
>>>
>>>
>>
>>
>> --
>> Best regards,
>> Wen-Han Gu (Nowar)
>>
>>
>


-- 
Best regards,
WenHan Gu (Nowar)
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