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?
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
>
