[PATCH] D34158: For standards compatibility, preinclude <stdc-predef.h> if the file is available

[Blower, Melanie via cfe-commits]

jyknight added a comment.

In https://reviews.llvm.org/D34158#823316, @fedor.sergeev wrote:

> Hmm... I tried this patch and now the following worries me:
>
> - it passes -finclude-if-exists stdc-predef.h on all platforms (say, including my Solaris platform that has no system stdc-predef.h)


Right, but Solaris probably _ought_ to add one as well, to define those macros.

> - it searches all the paths, not just "system include" ones
> 
>   That essentially disallows user to have stdc-predef.h include in my own project, since there is a chance that this user header will be accidentally included by this hidden machinery.

IMO, this is a fairly negligible issue, and so we go *shrug* oh well.

+1 for using a <> include -- that does seem better.

>> If I make a change like this: CmdArgs.push_back("<stdc-predef.h>"); the program fails to pre-include std-predef.h; so I assume that there is something that needs to be fixed with this line: Opts.FIncludeIfExists.emplace_back(A->getValue());   If we want those <> in there, but no extra " in there, I would need to study which value is returned and fiddle around with the characters to make sure the right thing gets put into the input stream. This will take me quite a bit more time since I know close to diddly at this point.

But, note, that will have no effect w.r.t. this issue for most users, since typically people use "cc -Isomepath", which adds 'somepath' to the list which gets searched by both <> and "" includes. Hardly anyone uses -iquote.


Repository:
  rL LLVM

https://reviews.llvm.org/D34158