[cfe-dev] MinGW(-w64) fixes to InitHeaderSearch.cpp and float.h

Ruben Van Boxem vanboxem.ruben at gmail.com
Tue Jul 5 09:07:29 PDT 2011

2011/7/5 Ruben Van Boxem <vanboxem.ruben at gmail.com>:
> 2011/7/5 Douglas Gregor <dgregor at apple.com>:
>> On Jul 4, 2011, at 12:30 PM, Ruben Van Boxem wrote:
>>> 2011/7/2 Ruben Van Boxem <vanboxem.ruben at gmail.com>:
>>>> 2011/7/2 Douglas Gregor <dgregor at apple.com>:
>>>>> On Jul 2, 2011, at 6:08 AM, Ruben Van Boxem wrote:
>>>>>> 2011/6/27 Ruben Van Boxem <vanboxem.ruben at gmail.com>:
>>>>>>> Op 27 jun. 2011 17:51 schreef "Douglas Gregor" <dgregor at apple.com> het volgende:
>>>>>>>> On Jun 25, 2011, at 7:51 AM, Ruben Van Boxem wrote:
>>>>>>>>> Hi,
>>>>>>>>> I bring fixes for MinGW(-w64) Clang users:
>>>>>>>>> 1. InitHeaderSearch.cpp: add a HeaderSearchOptions argument to
>>>>>>>>> AddDefaultCXXIncludePaths (AddDefaultCIncludePaths already had this,
>>>>>>>>> seems only logical to have it here) and use ResourceDir to find the
>>>>>>>>> sysroot of where Clang.exe is located. From there, add the
>>>>>>>>> x86_64-w64-mingw32 and i686-w64-mingw32 include paths for C and C++.
>>>>>>>>> All mingw-w64 toolchains are built --with-sysroot, and thus
>>>>>>>>> relocatable, so this change will always find the accompanying headers.
>>>>>>>> I've committed this part as r133911.
>>>>>>>>> 2. float.h: MinGW needs an #include_next, because as described on this
>>>>>>>>> page (http://msdn.microsoft.com/en-us/library/y0ybw9fy.aspx) there are
>>>>>>>>> non-standard extensions to float.h which are expected on Windows, and
>>>>>>>>> MinGW provides these declarations in their system header. GCC's
>>>>>>>>> float.h is "fixinclude"d to include_next the system header. Note that
>>>>>>>>> a trivial change is needed in mingw-w64's float.h, and that change
>>>>>>>>> will be committed as soon as Clang's header does what it's supposed to
>>>>>>>>> do.
>>>>>>>> If we're including MinGW's float.h first, then our own definitions of all of the standard float.h macros are going to stomp on the ones that come from MinGW's float.h. I think that's a reasonable thing to do, but if that's the intent, I'd prefer to have #undef's in our own float.h to make it explicit that this is what we're doing (and so that our own headers don't generate warnings, even if they're suppressed).
>>>>>>> I just copied that behavior (and the comment) from <stdint.h>, but I
>>>>>>> know that mingw-w64's float.h header does #undef everything it
>>>>>>> redefines, so it would perhaps be better if the #include_next in
>>>>>>> Clang's float.h came at the end. Then nothing else needs to change
>>>>>>> much.
>>>>>>> Ruben
>>>>>> I have attached a new patch with two new GCC versions for the include
>>>>>> paths, and I moved the #include_next <float.h> to the end. My previous
>>>>>> testing proved this would work if the mingw-w64 headers is adapted to
>>>>>> detect Clang as well (will happen as soon as Clang's header is
>>>>>> patched). If someone would be so kind to apply these minor changes,
>>>>>> I'd be very happy.
>>>>> My suggestion would have been to #include_next <float.h> at the beginning, then #undef everything that Clang's <float.h> is going to define, so that Clang is guaranteed to get its own definitions of the standard macros. Did this not work?
>>>> It does, I just tested it. Attached is your change.
>>>>> The patch you attached is something different (a CMake change for TableGen). Is that change still necessary?
>>>> Yes, terribly sorry for the bad attachment, I took the LLVM directory
>>>> instead of LLVM/tools/clang directory. Should have double-checked.
>>>> Ruben
>>> Sorry to be such a pain in the *ss, but I'd really like this patch in.
>>> Then I can build/release a mingw-w64 Clang build and you'll have a lot
>>> more testers for that platform (I hope).
>> It *is* a holiday weekend in the United States, where most of the code owners are located.
> So it is :) must have forgotten about that :s At least I know I'm a
> pain in the *ss. Thanks *very* much!
> Ruben

I just noticed the new float.h undef's everything twice if __MINGW32__
is defined. I assume it was the idea to remove the undef's outside of
the __MINGW32__ ifdef?

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