On 08/12/2016 01:27 PM, David Malcolm wrote:
In r239260 I attempted to add fix-it hints for -Wformat type warnings.Unfortunately, my implementation was too simplistic, and only worked correctly for the most simple format strings: the fix-it hint would suggest replacement of an entire conversion specification, but the replacement would only include the length modifier (if any) and the conversion character, thus effectively discarding any user-supplied flags, width, or precision. Additionally, the replacement failed to take into account the user-specified conversion character, so that e.g. an "x" could be replaced by a "d". The following patch fixes these issues by: (a) making the suggestion retain any user-supplied part of the conversion specification before the length modifier, and (b) attempt to preserve the user-specified conversion character, by first considering replacements that only change the length modifier. It also expands the function comments in c-format.c, showing how the functions work through a non-trivial example. This patch is a followup to: "[PATCH] Fix caret locations in format_type_warning (PR c/72857)" https://gcc.gnu.org/ml/gcc-patches/2016-08/msg00867.html Successfully bootstrapped®rtested on x86_64-pc-linux-gnu (on top of the other patch). OK for trunk? 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.
OK. jeff
