[PATCH] Prevent macro argument expansion when the LHS of concatenation is empty

[Argyrios Kyrtzidis]

Sorry for the delay, your patch looks great, I've committed in r182699.
Thanks!

On May 24, 2013, at 9:51 AM, Harald van Dijk <harald at gigawatt.nl> wrote:

> Sure, like so (as a separate patch)? I've verified that this passes testing, and reverting my TokenLexer.cpp changes makes the test fail as intended. Note that I have added the --strict-whitespace option even though there is no whitespace to be checked at the moment, because if a future check gets added that does include whitespace (I have plans for that), the option should probably be used, and it should be harmless otherwise. But if you disagree I have no objections to removing it. :)
> 
> On 24/05/13 17:57, Rafael Espíndola wrote:
>> Harald, can you convert macro_paste_empty.c to FileCheck while you are at it?
>> 
>> Argyrios, you are probably the best one to review the patch itself.
>> 
>> On 23 May 2013 17:01, Harald van Dijk <harald at gigawatt.nl> wrote:
>>> ping
>>> 
>>> Retested today, still applies cleanly, still passes testing.
>>> 
>>> 
>>> On 05/05/13 18:51, Harald van Dijk wrote:
>>>> 
>>>> ping
>>>> 
>>>> Note that all tests now pass, the failures I previously got were due to
>>>> local issues.
>>>> 
>>>> On 10/04/13 22:36, Harald van Dijk wrote:
>>>>> 
>>>>> Hi all,
>>>>> 
>>>>> As mentioned in http://llvm.org/bugs/show_bug.cgi?id=12767, and what I
>>>>> again reported as http://llvm.org/bugs/show_bug.cgi?id=15661, when
>>>>> concatenating x ## y, argument expansion for y should be suppressed even
>>>>> when x is empty. Does this approach look okay? All preprocessor tests
>>>>> pass, a few other tests were already failing for me and continue to fail
>>>>> the same way, there are no new failures.
>>>>> 
>>>>> This is my first contribution to clang, I am not yet familiar with the
>>>>> process. I should not need to do more than send this patch to the list,
>>>>> correct?
>>>>> 
>>>>> Cheers,
>>>>> Harald
> 
> <clang-macro_paste_empty-FileCheck.patch>