> Am 10.03.2025 um 08:35 schrieb Jakub Jelinek <ja...@redhat.com>:
>
> Hi!
>
> I've rushed up the PR117178 multi-dimensional nonstring support. Before
> a week off I've just bootstrapped/regtested the actual change, so
> handle_nonstring_attribute/get_attr_nonstring_decl adjustments after playing
> with simple short tests and left the testcases for the next day, where I've
> basically copied the attr-nonstring-{1,...,8}.c tests to
> attr-nonstring-{9,...,16}.c and adjusted them so that they test
> multi-dimensional nonstring instead of single-dimensional ones. But I
> forgot I haven't finished adjusting the dg-* lines and a few others to make
> all the tests pass and posted the patch for review anyway.
> When it got approved recently, I've only found out that some of the tests
> still FAIL when about to commit it and quickly adjusted them, but I've added
> 4 xfails in there. Sorry.
>
> The following patch fixes those 4 xfails (and results in 2 false positive
> warnings not being produced either).
> The thing is that maybe_warn_nonstring_arg simply assumed that nonstring
> arrays must be single-dimensional, so when it sees a nonstring decl with
> ARRAY_TYPE, it just used its dimension. With multi-dimensional arrays
> that is not the right dimension to use though, it can be dimension of
> some outer dimension, e.g. if we have
> char a[5][6][7] __attribute__((nonstring)) if decl is
> a[5] it would assume maximum non-NUL terminated string length of 5 rather than
> 7, if a[5][6] it would assume 6 and only for a[5][6][0] it would assume the
> correct 7. So, the following patch looks through all the outer dimensions
> to reach the innermost one (which for attribute nonstring is guaranteed to
> have char/unsigned char/signed char element type).
>
> Bootstrapped/regtested on x86_64-linux and i686-linux, ok for trunk?
Ok
Richard
> 2025-03-10 Jakub Jelinek <ja...@redhat.com>
>
> PR c/117178
> * gimple-ssa-warn-access.cc (maybe_warn_nonstring_arg): Look through
> multi-dimensional array types, stop at the innermost ARRAY_TYPE.
>
> * c-c++-common/attr-nonstring-11.c: Remove xfails.
> * c-c++-common/attr-nonstring-12.c (warn_strcmp_cst_1,
> warn_strcmp_cst_2): Don't expect any warnings here.
> (warn_strcmp_cst_3, warn_strcmp_cst_4): New functions with expected
> warnings.
>
> --- gcc/gimple-ssa-warn-access.cc.jj 2025-01-02 11:23:17.000000000 +0100
> +++ gcc/gimple-ssa-warn-access.cc 2025-03-08 11:44:09.304064889 +0100
> @@ -602,6 +602,10 @@ maybe_warn_nonstring_arg (tree fndecl, G
> bool known_size = false;
> tree type = TREE_TYPE (decl);
>
> + while (TREE_CODE (type) == ARRAY_TYPE
> + && TREE_CODE (TREE_TYPE (type)) == ARRAY_TYPE)
> + type = TREE_TYPE (type);
> +
> /* Determine the array size. For arrays of unknown bound and
> pointers reset BOUND to trigger the appropriate warning. */
> if (TREE_CODE (type) == ARRAY_TYPE)
> --- gcc/testsuite/c-c++-common/attr-nonstring-11.c.jj 2025-03-08
> 00:49:09.958121143 +0100
> +++ gcc/testsuite/c-c++-common/attr-nonstring-11.c 2025-03-08
> 11:50:15.513041709 +0100
> @@ -165,8 +165,8 @@ void test_strcmp (struct MemArrays *p)
> void test_strncmp_warn (struct MemArrays *p)
> {
> enum { N = sizeof arr[2] };
> - T (strncmp (str[2], arr[2], N)); /* { dg-bogus "argument 2 declared
> attribute 'nonstring' is smaller than the specified bound 4" "" { xfail *-*-*
> } } */
> - T (strncmp (arr[2], str[2], N)); /* { dg-bogus "argument 1 declared
> attribute 'nonstring' is smaller than the specified bound 4" "" { xfail *-*-*
> } } */
> + T (strncmp (str[2], arr[2], N));
> + T (strncmp (arr[2], str[2], N));
>
> T (strncmp (str[2], arr[2], N + 1)); /* { dg-warning "argument 2 declared
> attribute .nonstring. is smaller than the specified bound 5" } */
> T (strncmp (arr[2], str[2], N + 1)); /* { dg-warning "argument 1 declared
> attribute .nonstring. is smaller than the specified bound 5" } */
> @@ -237,7 +237,7 @@ void test_stpncpy_warn (struct MemArrays
> enum { N = sizeof arr[2] };
>
> T (stpncpy (str[2], str[2], N));
> - T (stpncpy (str[2], arr[2], N)); /* { dg-bogus "argument 2 declared
> attribute 'nonstring' is smaller than the specified bound 4" "" { xfail *-*-*
> } } */
> + T (stpncpy (str[2], arr[2], N));
> T (stpncpy (arr[2], str[2], N));
>
> T (stpncpy (str[2], *ptr, N));
> @@ -370,7 +370,7 @@ void test_stnrdup_warn (struct MemArrays
> enum { N = sizeof arr[2] };
>
> T (strndup (str[2], N));
> - T (strndup (arr[2], N)); /* { dg-bogus "argument 1 declared attribute
> 'nonstring' is smaller than the specified bound 4" "" { xfail *-*-* } } */
> + T (strndup (arr[2], N));
>
> T (strndup (*ptr, N));
> T (strndup (*parr, N));
> --- gcc/testsuite/c-c++-common/attr-nonstring-12.c.jj 2025-03-08
> 00:07:01.879907901 +0100
> +++ gcc/testsuite/c-c++-common/attr-nonstring-12.c 2025-03-08
> 11:52:11.850445944 +0100
> @@ -26,12 +26,22 @@ enum { X = sizeof ar5[2] + 1 };
>
> int warn_strcmp_cst_1 (void)
> {
> - return strcmp ("bar", arx[3]); /* { dg-warning "argument 2 declared
> attribute .nonstring." } */
> + return strcmp ("bar", arx[3]);
> }
>
> int warn_strcmp_cst_2 (void)
> {
> - return strcmp (arx[3], "foo"); /* { dg-warning "argument 1 declared
> attribute .nonstring." } */
> + return strcmp (arx[3], "foo");
> +}
> +
> +int warn_strcmp_cst_3 (void)
> +{
> + return strcmp ("barfoobazquxcorge1", arx[3]); /* { dg-warning
> "argument 2 declared attribute .nonstring." } */
> +}
> +
> +int warn_strcmp_cst_4 (void)
> +{
> + return strcmp (arx[3], "foobarbazquxcorge1"); /* { dg-warning
> "argument 1 declared attribute .nonstring." } */
> }
>
>
>
> Jakub
>
