[Bug preprocessor/78569] "internal compiler error: in get_substring_ranges_for_loc" processing sprintf buffer overflow

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

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=78569

--- Comment #5 from David Malcolm <dmalcolm at gcc dot gnu.org> ---
Author: dmalcolm
Date: Wed Nov 30 01:13:37 2016
New Revision: 242990

URL: https://gcc.gnu.org/viewcvs?rev=242990&root=gcc&view=rev
Log:
substring locations and # line directives (PR preprocessor/78569)

The ICE in PR preprocessor/78569 appears to be due to an attempt to
generate substring locations in a .i file where the underlying .c file
has changed since the .i file was generated.

This can't work, so it seems safest for the on-demand substring
locations to be unavailable for such files, falling back to
"whole string" locations for such cases.

gcc/ChangeLog:
        PR preprocessor/78569
        * input.c (get_substring_ranges_for_loc): Fail gracefully if
        line directives were present.

gcc/testsuite/ChangeLog:
        PR preprocessor/78569
        * gcc.dg/format/pr78569.c: New test case.

Added:
    trunk/gcc/testsuite/gcc.dg/format/pr78569.c
Modified:
    trunk/gcc/ChangeLog
    trunk/gcc/input.c
    trunk/gcc/testsuite/ChangeLog