On Tue, May 28, 2024 at 1:21 PM David Malcolm <dmalc...@redhat.com> wrote: > > Ping. > > This patch has actually been *very* helpful to me when debugging > selftest failures involving ASSERT_STREQ. > > Thanks > Dave >
Currently `diff` is only listed under the "Tools/packages necessary for modifying GCC" section of install/prerequisites.html: https://gcc.gnu.org/install/prerequisites.html If it's going to become a dependency for actually running GCC, too, it should get moved to be documented elsewhere, IMO. > 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); > > + } > > } > > } > > >
