On 01/30/2017 02:28 PM, Martin Sebor wrote:
Bug 79275 - -Wformat-overflow false positive exceeding INT_MAX in
glibc sysdeps/posix/tempname.c points out a false positive found
during a Glibc build and caused by the checker using the upper
bound of a range of precisions in string directives with string
arguments of non-constant length. The attached patch relaxes
the checker to use the lower bound instead when appropriate.
Martin
gcc-79275.diff
PR middle-end/79275 - -Wformat-overflow false positive exceeding INT_MAX in
glibc sysdeps/posix/tempname.c
gcc/testsuite/ChangeLog:
PR middle-end/79275
* gcc.dg/tree-ssa/builtin-sprintf-warn-11.c: New test.
* gcc.dg/tree-ssa/pr79275.c: New test.
gcc/ChangeLog:
PR middle-end/79275
* gimple-ssa-sprintf.c (get_string_length): Set lower bound to zero.
(format_string): Tighten up the range of output for non-constant
strings and correct the expected range for wide non-constant strings.
Couple more nits.
First, I expect the patch won't apply as-is with the operand order
fixes. There'll be trivial changes you'll need to make for that.
Along the same lines, this patch would introduce a new operand order nit
here:
+ }
+ else if (0 <= dir.prec[1])
+ {
Please consider documenting how we handle strings with unknown lengths.
I don't think those warrant waiting for another review round. Fix,
bootstrap, test and install.
jeff
