[Bug preprocessor/61832] New: r212638 breaks building ncurses

[Bug preprocessor/61832] New: r212638 breaks building ncurses

[ktkachov at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=61832

            Bug ID: 61832
           Summary: r212638 breaks building ncurses
           Product: gcc
           Version: 4.10.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: preprocessor
          Assignee: unassigned at gcc dot gnu.org
          Reporter: ktkachov at gcc dot gnu.org

As of 212638:

    gcc/c-family/ChangeLog:
        * c-ppoutput.c (struct print::prev_was_system_token): New data
        member.
        (init_pp_output): Initialize it.
        (maybe_print_line_1, maybe_print_line, print_line_1, print_line)
        (do_line_change): Return a flag saying if a line marker was
        emitted or not.
        (scan_translation_unit): Detect if the system-ness of the token we
        are about to emit is different from the one of the previously
        emitted token.  If so, emit a line marker.  Avoid emitting useless
        adjacent line markers.  Avoid emitting line markers for tokens
        originating from the expansion of built-in macros.
        (scan_translation_unit_directives_only): Adjust.

by dodji

gcc fails to build ncurses. Basically the preprocessor ends up generating
invalid C-code.

I'll try to reduce a testcase soon, but in the meantime this appears on x86,
arm and aarch64 so should be easily reproducible

[Bug preprocessor/61832] [4.10 Regression] r212638 breaks building ncurses

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=61832

Richard Biener <rguenth at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
   Target Milestone|---                         |4.10.0
            Summary|r212638 breaks building     |[4.10 Regression] r212638
                   |ncurses                     |breaks building ncurses

[Bug preprocessor/61832] [4.10 Regression] r212638 breaks building ncurses

[ktkachov at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=61832

ktkachov at gcc dot gnu.org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |RESOLVED
         Resolution|---                         |INVALID

--- Comment #1 from ktkachov at gcc dot gnu.org ---
I'm closing this as invalid.
The bug is in the ncurses build process which assumes that the preprocessor
does not introduce new lines and mangles the output with its own sed and awk
trickery which ends up stumbling on the new chanes