OK I am going to submit a new version which is now in 4 steps. The first 3 steps are entirely behavior non-changing (or at least that is their intent) --- pure refactors. The 4th and final one along does the behavior change, and contains the motivation for that behavior change. Clang prior art is no longer mentioned at the beginning of the motivation :).
Cheers, John On Wed, Aug 6, 2025, at 12:57 AM, Andrew Pinski wrote: > On Tue, Aug 5, 2025 at 9:54 PM Andrew Pinski <pins...@gmail.com> wrote: > > > > On Tue, Aug 5, 2025 at 9:50 PM John Ericson <g...@johnericson.me> wrote: > > > > > > This matches the behavior of Clang, and makes it easier to work with > > > cross compilers without heeding to hard-code paths at build time. > > > > Does it really make sense to match clang here? > > The paths are relocable already too. > > Can you expand on why you need/want this change? Since it changes > > behavior that has been around for over 25 years now? > > Also read > https://inbox.sourceware.org/gcc-patches/20240522095404.1825269-1-...@gcc.gnu.org/ > thread which was doing something slightly different but related. > > > > > Thanks, > > Andrew > > > > > > > > gcc/ChangeLog: > > > > > > * gcc.cc (file_at_path): Remove program suffix logic (it is > > > moving elsewhere). This function no longer cares about programs > > > in particular, matching its name. > > > (program_at_path): New function that does care about programs in > > > particular. It has the preexisting suffixing logic (moved here) > > > and the new prefixing logic. > > > (find_a_program): Instead work by using for_each_path with > > > file_at_path, just as find_a_file uses file_at_path. > > > (driver::set_up_specs): Initial just_machine_prefix, a constant > > > used above. > > > > > > Signed-off-by: John Ericson <g...@johnericson.me> > > > --- > > > gcc/gcc.cc | 76 +++++++++++++++++++++++++++++++++++++++++++++++------- > > > 1 file changed, 66 insertions(+), 10 deletions(-) > > > > > > diff --git a/gcc/gcc.cc b/gcc/gcc.cc > > > index bfa588ee5f0..d3ba4d6565b 100644 > > > --- a/gcc/gcc.cc > > > +++ b/gcc/gcc.cc > > > @@ -1600,6 +1600,11 @@ static const char *machine_suffix = 0; > > > > > > static const char *just_machine_suffix = 0; > > > > > > +/* Prefix to attach to *basename* of commands being searched. > > > + This is just `MACHINE-'. */ > > > + > > > +static const char *just_machine_prefix = 0; > > > + > > > /* Adjusted value of GCC_EXEC_PREFIX envvar. */ > > > > > > static const char *gcc_exec_prefix; > > > @@ -3043,15 +3048,6 @@ file_at_path (char *path, void *data) > > > memcpy (path + len, info->name, info->name_len); > > > len += info->name_len; > > > > > > - /* Some systems have a suffix for executable files. > > > - So try appending that first. */ > > > - if (info->suffix_len) > > > - { > > > - memcpy (path + len, info->suffix, info->suffix_len + 1); > > > - if (access_check (path, info->mode) == 0) > > > - return path; > > > - } > > > - > > > path[len] = '\0'; > > > if (access_check (path, info->mode) == 0) > > > return path; > > > @@ -3091,6 +3087,44 @@ find_a_file (const struct path_prefix *pprefix, > > > const char *name, int mode, > > > file_at_path, &info); > > > } > > > > > > +/* Callback for find_a_program. Appends the file name to the directory > > > + path. Like file_at_path but tries machine prefix and exe suffix too. > > > */ > > > + > > > +static void * > > > +program_at_path (char *path, void *data) > > > +{ > > > + /* try first with machine-prefixed name */ > > > + struct file_at_path_info *info = (struct file_at_path_info *) data; > > > + size_t path_len = strlen (path); > > > + > > > + for (auto prefix : { just_machine_prefix, "" }) > > > + { > > > + auto len = path_len; > > > + > > > + auto prefix_len = strlen(prefix); > > > + memcpy (path + len, prefix, prefix_len); > > > + len += prefix_len; > > > + > > > + memcpy (path + len, info->name, info->name_len); > > > + len += info->name_len; > > > + > > > + /* Some systems have a suffix for executable files. > > > + So try appending that first. */ > > > + if (info->suffix_len) > > > + { > > > + memcpy (path + len, info->suffix, info->suffix_len + 1); > > > + if (access_check (path, info->mode) == 0) > > > + return path; > > > + } > > > + > > > + path[len] = '\0'; > > > + if (access_check (path, info->mode) == 0) > > > + return path; > > > + } > > > + > > > + return NULL; > > > +} > > > + > > > /* Specialization of find_a_file for programs that also takes into > > > account > > > configure-specified default programs. */ > > > > > > @@ -3114,7 +3148,28 @@ find_a_program (const char *name) > > > return xstrdup (DEFAULT_DSYMUTIL); > > > #endif > > > > > > - return find_a_file (&exec_prefixes, name, X_OK, false); > > > + /* Find the filename in question (special case for absolute paths). */ > > > + > > > + if (IS_ABSOLUTE_PATH (name)) > > > + { > > > + if (access (name, mode) == 0) > > > + return xstrdup (name); > > > + > > > + return NULL; > > > + } > > > + > > > + struct file_at_path_info info; > > > + > > > + info.name = name; > > > + info.suffix = HOST_EXECUTABLE_SUFFIX; > > > + info.name_len = strlen (info.name); > > > + info.suffix_len = strlen (info.suffix); > > > + info.mode = X_OK; > > > + > > > + return (char*) for_each_path ( > > > + &exec_prefixes, false, > > > + info.name_len + info.suffix_len + strlen(just_machine_prefix), > > > + program_at_path, &info); > > > } > > > > > > /* Ranking of prefixes in the sort list. -B prefixes are put before > > > @@ -8493,6 +8548,7 @@ driver::set_up_specs () const > > > machine_suffix = concat (spec_host_machine, dir_separator_str, > > > spec_version, > > > accel_dir_suffix, dir_separator_str, NULL); > > > just_machine_suffix = concat (spec_machine, dir_separator_str, NULL); > > > + just_machine_prefix = concat (spec_machine, "-", NULL); > > > > > > specs_file = find_a_file (&startfile_prefixes, "specs", R_OK, true); > > > /* Read the specs file unless it is a default one. */ > > > -- > > > 2.49.0 > > > >
