[Bug preprocessor/28435] -MMD vs not found system header (included from a system header)

["tromey at gcc dot gnu dot org" <gcc-bugzilla at gcc dot gnu dot org>]

------- Comment #6 from tromey at gcc dot gnu dot org  2008-05-09 23:02 -------
I think we should give an error by default, and only *not* give an
error if -MG is passed.  My reasoning is that -MG exists only to disable
this error.  I couldn't think of a reason to disable it in other cases.
For instance, it seems to me that "gcc -E" should fail if a header is missing.

I looked at open_file_failed, but I don't understand the reasoning behind
a lot of the logic in there (though see PR 15220).

A comment says:

      /* If we are outputting dependencies but not for this file then
         don't error because we can still produce correct output.  */

... but this seems to be based on incorrect logic to me.  A <> include
may define something which affects later inclusions.

I wonder if anybody relies on the current, bogus, behavior.


-- 

tromey at gcc dot gnu dot org changed:

           What    |Removed                     |Added
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                 CC|                            |tromey at gcc dot gnu dot
                   |                            |org


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=28435