[Bug c/72858] incorrect fixit hints in -Wformat diagnostics

[dmalcolm at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=72858

--- Comment #2 from David Malcolm <dmalcolm at gcc dot gnu.org> ---
Author: dmalcolm
Date: Mon Sep 12 16:01:02 2016
New Revision: 240095

URL: https://gcc.gnu.org/viewcvs?rev=240095&root=gcc&view=rev
Log:
Fix suggestions for non-trivial Wformat type cases (PR c/72858)

gcc/c-family/ChangeLog:
        PR c/72858
        * c-format.c (argument_parser::check_argument_type): Add params
        "type_start" and "conversion_char".  Use the former to generate
        offset_to_type_start and pass it and conversion_char to
        check_format_types.
        (check_format_info_main): Capture the start of the type
        information as "type_start", and pass it an format_char
        to arg_parser.check_argument_type.
        (check_format_types): Provide an example in the leading comment.
        Add params "offset_to_type_start" and "conversion_char"; pass
        them to format_type_warning calls.
        (test_get_modifier_for_format_len): Likewise.
        (matching_type_p): New function.
        (get_format_for_type): Add param "conversion_char" and move
        implementation into...
        (get_format_for_type_1): ...new function, called twice.
        Use new function matching_type_p rather than checking for
        TYPE_CANONICAL equality.
        (get_corrected_substring): New function.
        (format_type_warning): Provide an example in the leading comment.
        Add params "offset_to_type_start" and "conversion_char".  Replace
        call to get_format_for_type with call to get_corrected_substring
        and move rejection of hints for widths/precisions there.
        (assert_format_for_type_streq): Add param "conversion_char".
        (ASSERT_FORMAT_FOR_TYPE_STREQ): Add param CONVERSION_CHAR.
        (test_get_format_for_type_printf): Add conversion chars to the
        tests, adding coverage for various combinations of integer
        vs double conversions, and for preserving octal and hexadecimal
        conversions.
        (test_get_format_for_type_scanf): Add conversion chars to the
        tests.

gcc/testsuite/ChangeLog:
        PR c/72858
        * gcc.dg/format/diagnostic-ranges.c: Update expected suggestions
        to preserve conversion chars, and to preserve prefix information.
        * gcc.dg/format/pr72858.c: New test case.


Added:
    trunk/gcc/testsuite/gcc.dg/format/pr72858.c
Modified:
    trunk/gcc/c-family/ChangeLog
    trunk/gcc/c-family/c-format.c
    trunk/gcc/testsuite/ChangeLog
    trunk/gcc/testsuite/gcc.dg/format/diagnostic-ranges.c