[cfe-commits] r162810 - in /cfe/trunk: include/clang/Lex/MacroInfo.h include/clang/Lex/Preprocessor.h lib/Frontend/PrintPreprocessedOutput.cpp lib/Lex/MacroInfo.cpp lib/Lex/PPDirectives.cpp lib/Lex/PPMacroExpansion.cpp lib/Lex/Pragma.cpp lib/Sema

[Richard Smith]

Neither the old nor new behavior is correct, according to the GCC
specification for how directives within macro arguments should work. Should
be fixed in r162906.

On Wed, Aug 29, 2012 at 6:04 PM, Alexander Kornienko <alexfh at google.com>wrote:

> +chandlerc, richardsmith, klimek, dgregor
>
> Yes, it's really my patch, but I'm not really sure if we want to fix this.
>
> Any idea of whether we should care about this behavior or not?
>
>
> On Wed, Aug 29, 2012 at 5:48 PM, Alexander Kornienko <alexfh at google.com>wrote:
>
>> I'm not really sure if that was my patch, but I'm looking into it now.
>>
>> Anyone else has any preferences except compatibility with gcc?
>>
>>
>> On Wed, Aug 29, 2012 at 5:16 PM, Eli Friedman <eli.friedman at gmail.com>wrote:
>>
>>> On Wed, Aug 29, 2012 at 4:40 PM, Alexander Kornienko <alexfh at google.com>
>>> wrote:
>>> > No, there was no intention to change behavior. But could you provide
>>> more
>>> > details on this?
>>>
>>> Just compile it with clang; before, it would fail to compile:
>>> [...]gcc-4_2-testsuite/src/gcc.dg/cpp/mac-dir-1.c:27:15: error: too
>>> many arguments provided to function-like macro invocation
>>>      if (1 != f(2
>>>               ^
>>> [...]/gcc-4_2-testsuite/src/gcc.dg/cpp/mac-dir-1.c:27:15: error: use
>>> of undeclared identifier 'f'
>>>
>>> With your patch, it compiles without errors, but the compiled program
>>> aborts.  For comparison, with gcc, the program compiles and runs
>>> successfully.  (I'm pretty sure this is all undefined behavior per
>>> C99, but it would be nice to be consistent with gcc.)
>>>
>>> -Eli
>>>
>>
>>
>>
>> --
>> Regards,
>> Alex
>>
>
>
>
> --
> Regards,
> Alex
>
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