[PATCH] D34158: to support gcc 4.8 (and newer) compatibility on Linux, preinclude <stdc-predef.h>

[Melanie Blower via Phabricator via cfe-commits]

mibintc added a comment.

In https://reviews.llvm.org/D34158#782467, @fedor.sergeev wrote:

> LGTM wrt your update to sources.
>  And sorry, I'm not that qualified to answer your question on failing tests.
>
> Probing existence of this header would make a sense, yet you are including it w/o a full path, so how are you going to find it for this probe?


Yes, I'd have to change this patch to iterate through the system headers.  Once I found an instance I'd keep the full path name and -include it using full  path name.  I'll go ahead and change the patch to do this.

The other thought I had is: don't check for gcc version -- just add this functionality for all gcc versions on Linux. The reason I'd do that is to avoid creating lit test failures when the lit tests are running with gcc versions less than gcc 4.8; thus far I've been able to fix the lit failures by adding "-nostdinc".   Adding "-nostdinc" to the tests would work regardless of gcc version.  But I'm concerned that I will need to update some of the lit tests by checking for different output. In that case the expected output would differ based on gcc version, and I don't know if it's possible to express "don't run this lit test for gcc< 4.8".


Repository:
  rL LLVM

https://reviews.llvm.org/D34158