On Mon, Aug 10, 2026 at 12:03 AM John Ericson <[email protected]> wrote:
>
> The loop that splits a PATH_SEPARATOR separated environment variable and
> adds each directory as a prefix was written out three times, for
> COMPILER_PATH, LIBRARY_PATH and LPATH, differing only in which prefix
> list each directory is added to.
>
> Factor it out into for_each_env_path, a sibling of for_each_path that
> takes a callback the same way. Handling a null value in the helper also
> lets the two startfile users share one 'cross_compile' test and one
> callback, rather than repeating both.
>
> No functional change.
>
> gcc/ChangeLog:
>
> * gcc.cc (for_each_env_path): New function template.
> (process_command): Use it for COMPILER_PATH, LIBRARY_PATH and
> LPATH.
>
> Signed-off-by: John Ericson <[email protected]>
> ---
> gcc/gcc.cc | 148 +++++++++++++++++++++--------------------------------
> 1 file changed, 57 insertions(+), 91 deletions(-)
>
> diff --git a/gcc/gcc.cc b/gcc/gcc.cc
> index 973a3402330..08a192ade76 100644
> --- a/gcc/gcc.cc
> +++ b/gcc/gcc.cc
> @@ -2983,6 +2983,51 @@ for_each_path (const struct path_prefix *paths,
> return ret;
> }
>
> +/* Call CALLBACK once per directory named in VALUE, a PATH_SEPARATOR
> + separated list such as the value of COMPILER_PATH or PATH. VALUE may be
> + null, in which case CALLBACK is not called at all.
> +
> + An empty element denotes the current directory. Each directory is passed
> + with a trailing directory separator, as add_prefix expects. The buffer
> + handed to CALLBACK is reused between iterations, so CALLBACK must copy
> + anything it wants to keep -- add_prefix does. */
> +
> +template<typename fun>
> +static void
> +for_each_env_path (const char *value, fun callback)
Do we have a callback that needs some other data passed to it?
If not then I would not make this a template and just make the
callback argument a function type `void (*)(const char*)`.
> +{
> + if (!value)
> + return;
> +
> + char *nstore = (char *) alloca (strlen (value) + 3);
> +
> + for (const char *startp = value, *endp = value; ; endp++)
> + {
> + if (*endp != PATH_SEPARATOR && *endp != 0)
> + continue;
> +
> + if (endp == startp)
> + strcpy (nstore, concat (".", dir_separator_str, NULL));
> + else
> + {
> + strncpy (nstore, startp, endp - startp);
> + if (!IS_DIR_SEPARATOR (endp[-1]))
> + {
> + nstore[endp - startp] = DIR_SEPARATOR;
> + nstore[endp - startp + 1] = 0;
> + }
> + else
> + nstore[endp - startp] = 0;
> + }
> +
> + callback (nstore);
> +
> + if (*endp == 0)
> + break;
> + startp = endp + 1;
> + }
> +}
> +
> /* Add or change the value of an environment variable, outputting the
> change to standard error if in verbose mode. */
> static void
> @@ -4962,103 +5007,24 @@ process_command (unsigned int decoded_options_count,
> /* COMPILER_PATH and LIBRARY_PATH have values
> that are lists of directory names with colons. */
>
> - temp = env.get ("COMPILER_PATH");
> - if (temp)
> + for_each_env_path (env.get ("COMPILER_PATH"), [] (const char *dir)
> {
> - const char *startp, *endp;
> - char *nstore = (char *) alloca (strlen (temp) + 3);
> -
> - startp = endp = temp;
> - while (1)
> - {
> - if (*endp == PATH_SEPARATOR || *endp == 0)
> - {
> - strncpy (nstore, startp, endp - startp);
> - if (endp == startp)
> - strcpy (nstore, concat (".", dir_separator_str, NULL));
> - else if (!IS_DIR_SEPARATOR (endp[-1]))
> - {
> - nstore[endp - startp] = DIR_SEPARATOR;
> - nstore[endp - startp + 1] = 0;
> - }
> - else
> - nstore[endp - startp] = 0;
> - add_prefix (&exec_prefixes, nstore, 0,
> - PREFIX_PRIORITY_LAST, 0, 0);
> - add_prefix (&include_prefixes, nstore, 0,
> - PREFIX_PRIORITY_LAST, 0, 0);
> - if (*endp == 0)
> - break;
> - endp = startp = endp + 1;
> - }
> - else
> - endp++;
> - }
> - }
> + add_prefix (&exec_prefixes, dir, 0, PREFIX_PRIORITY_LAST, 0, 0);
> + add_prefix (&include_prefixes, dir, 0, PREFIX_PRIORITY_LAST, 0, 0);
> + });
>
> - temp = env.get (LIBRARY_PATH_ENV);
> - if (temp && *cross_compile == '0')
> + if (*cross_compile == '0')
> {
> - const char *startp, *endp;
> - char *nstore = (char *) alloca (strlen (temp) + 3);
> -
> - startp = endp = temp;
> - while (1)
> + auto add_startfile_prefix = [] (const char *dir)
> {
> - if (*endp == PATH_SEPARATOR || *endp == 0)
> - {
> - strncpy (nstore, startp, endp - startp);
> - if (endp == startp)
> - strcpy (nstore, concat (".", dir_separator_str, NULL));
> - else if (!IS_DIR_SEPARATOR (endp[-1]))
> - {
> - nstore[endp - startp] = DIR_SEPARATOR;
> - nstore[endp - startp + 1] = 0;
> - }
> - else
> - nstore[endp - startp] = 0;
> - add_prefix (&startfile_prefixes, nstore, NULL,
> - PREFIX_PRIORITY_LAST, 0, 1);
> - if (*endp == 0)
> - break;
> - endp = startp = endp + 1;
> - }
> - else
> - endp++;
> - }
> - }
> + add_prefix (&startfile_prefixes, dir, NULL,
> + PREFIX_PRIORITY_LAST, 0, 1);
> + };
>
> - /* Use LPATH like LIBRARY_PATH (for the CMU build program). */
> - temp = env.get ("LPATH");
> - if (temp && *cross_compile == '0')
> - {
> - const char *startp, *endp;
> - char *nstore = (char *) alloca (strlen (temp) + 3);
> + for_each_env_path (env.get (LIBRARY_PATH_ENV), add_startfile_prefix);
>
> - startp = endp = temp;
> - while (1)
> - {
> - if (*endp == PATH_SEPARATOR || *endp == 0)
> - {
> - strncpy (nstore, startp, endp - startp);
> - if (endp == startp)
> - strcpy (nstore, concat (".", dir_separator_str, NULL));
> - else if (!IS_DIR_SEPARATOR (endp[-1]))
> - {
> - nstore[endp - startp] = DIR_SEPARATOR;
> - nstore[endp - startp + 1] = 0;
> - }
> - else
> - nstore[endp - startp] = 0;
> - add_prefix (&startfile_prefixes, nstore, NULL,
> - PREFIX_PRIORITY_LAST, 0, 1);
> - if (*endp == 0)
> - break;
> - endp = startp = endp + 1;
> - }
> - else
> - endp++;
> - }
> + /* Use LPATH like LIBRARY_PATH (for the CMU build program). */
> + for_each_env_path (env.get ("LPATH"), add_startfile_prefix);
> }
>
> /* Process the options and store input files and switches in their
>
> base-commit: c31b7a09eea3c33bccca12bab4a7bb6b01da1ff6
> --
> 2.54.0
>
