Ping.
This patch has actually been *very* helpful to me when debugging
selftest failures involving ASSERT_STREQ.
Thanks
Dave
On Fri, 2024-05-17 at 15:51 -0400, David Malcolm wrote:
> Currently when ASSERT_STREQ or ASSERT_STREQ_AT fail we print
> both strings to stderr. However it can be hard to figure out
> the problem (e.g. for 1-character differences in long strings).
>
> Extend the output by writing out the strings to tempfiles and
> invoking "diff -up" on them when we have such a selftest failure,
> to (I hope) simplify debugging.
>
> Successfully bootstrapped & regrtested on x86_64-pc-linux-gnu.
>
> OK for trunk?
>
> gcc/ChangeLog:
> * selftest.cc (selftest::print_diff): New function.
> (selftest::assert_streq): Call it when we have non-equal
> non-null strings.
>
> Signed-off-by: David Malcolm <dmalc...@redhat.com>
> ---
> gcc/selftest.cc | 28 ++++++++++++++++++++++++++--
> 1 file changed, 26 insertions(+), 2 deletions(-)
>
> diff --git a/gcc/selftest.cc b/gcc/selftest.cc
> index 6438d86a6aa0..f58c0631908e 100644
> --- a/gcc/selftest.cc
> +++ b/gcc/selftest.cc
> @@ -63,6 +63,26 @@ fail_formatted (const location &loc, const char
> *fmt, ...)
> abort ();
> }
>
> +/* Invoke "diff" to print the difference between VAL1 and VAL2
> + on stdout. */
> +
> +static void
> +print_diff (const location &loc, const char *val1, const char *val2)
> +{
> + temp_source_file tmpfile1 (loc, ".txt", val1);
> + temp_source_file tmpfile2 (loc, ".txt", val2);
> + const char *args[] = {"diff",
> + "-up",
> + tmpfile1.get_filename (),
> + tmpfile2.get_filename (),
> + NULL};
> + int exit_status = 0;
> + int err = 0;
> + pex_one (PEX_SEARCH | PEX_LAST,
> + args[0], CONST_CAST (char **, args),
> + NULL, NULL, NULL, &exit_status, &err);
> +}
> +
> /* Implementation detail of ASSERT_STREQ.
> Compare val1 and val2 with strcmp. They ought
> to be non-NULL; fail gracefully if either or both are NULL. */
> @@ -89,8 +109,12 @@ assert_streq (const location &loc,
> if (strcmp (val1, val2) == 0)
> pass (loc, "ASSERT_STREQ");
> else
> - fail_formatted (loc, "ASSERT_STREQ (%s, %s)\n val1=\"%s\"\n
> val2=\"%s\"\n",
> - desc_val1, desc_val2, val1, val2);
> + {
> + print_diff (loc, val1, val2);
> + fail_formatted
> + (loc, "ASSERT_STREQ (%s, %s)\n val1=\"%s\"\n
> val2=\"%s\"\n",
> + desc_val1, desc_val2, val1, val2);
> + }
> }
> }
>
