On 08/04/2018 12:46 PM, Martin Sebor wrote: > The sprintf handling of wide characters neglects to consider > that calling the function may fail due to a conversion error > (when the wide character is invalid or not representable in > the current locale). The handling also misinterprets > the POSIX %S wide string directive as a plain narrow %s and > doesn't include %C (the POSIX equivalent of %lc). The attached > patch corrects these oversights by extending the data structures > to indicate when a directive may fail, and extending the UNDER4K > member of the format_result structure to also encode calls with > such directives. > > Tested on x86_64-linux. > > Besides the trunk, since this bug can affect code correctness > I'd like to backport this patch to both release branches (7 > and 8). > > Martin > > gcc-86853.diff > > > PR tree-optimization/86853 - sprintf optimization for wide strings doesn't > account for conversion failure > > gcc/ChangeLog: > > PR tree-optimization/86853 > * gimple-ssa-sprintf.c (struct format_result): Rename member. > (struct fmtresult): Add member and initialize it in ctors. > (format_character): Handle %C. Extend range to NUL. Set MAYFAIL. > (format_string): Handle %S the same as %ls. Set MAYFAIL. > (format_directive): Set POSUNDER4K when MAYFAIL is set. > (parse_directive): Handle %C same as %c. > (sprintf_dom_walker::compute_format_length): Adjust. > (is_call_safe): Adjust. > > gcc/testsuite/ChangeLog: > > PR tree-optimization/86853 > * gcc.dg/tree-ssa/builtin-sprintf-10.c: New test. > * gcc.dg/tree-ssa/builtin-sprintf-11.c: New test. > * gcc.dg/tree-ssa/builtin-sprintf-warn-18.c: Adjust. I fixed two "empty" mis-spellings in gimple-ssa-sprintf.c and installed this patch.
Let's give it a few days of soak time, then backporting is fine. Jeff
