Resent with the patch expanded correctly (I guess, it wasn't because of UTF-8
encoding...).
Hi everyone,
Since noone answered, I assume that MULTILIB_REUSE was indeed not the solution.
Thus, I've implemented a solution using a new target macro MULTILIB_FALLBACK.
It allows any target to return a new multilib suffix based on the current
one being used by the algorithm. This solution is much simpler than
adding a new Makefile option like MULTILIB_REUSE and it allows targets
to fully control the new suffix, which can be an advantage.
However, this solution is not perfect. Especially, MULTILIB_FALLBACK must take
care of freeing "curr_multilib_dir" array, which might not be the best thing to
do. But letting "for_each_path" doing it is created a much more complex code,
which isn't better in my opinion.
Anyway, is a patch like the following one seems possible to be integrated or
should I search for a better solution ?
Thanks,
Clément
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>From 73efb4cc50a221ed45a4d44c06157fcf9124e320 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Cl=C3=A9ment=20Chigot?= <clement.chi...@atos.net>
Date: Mon, 12 Oct 2020 11:37:13 +0200
Subject: [PATCH] gcc: implement multilib fallbacks
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit
Some targets needs to be able to fallback from multilib A to
multilib B if multilib A isn't available at runtime.
Currently, the searched paths generated by gcc only include a single
multilib suffix and the default library.
This patch adds MULTILIB_FALLBACK macro to allow targets to get extra
multlib suffixes in these paths.
gcc/ChangeLog:
2020-10-12 Clément Chigot <clement.chi...@atos.net>
* config/rs6000/aix.h (MULTILIB_FALLBACK): New Define
* gcc.c (for_each_path): Allow several multilib suffixes
to be tried, based on MULTILIB_FALLBACK macro.
---
gcc/config/rs6000/aix.h | 21 +++++++++++++++
gcc/gcc.c | 60 ++++++++++++++++++++++++++++++-----------
2 files changed, 66 insertions(+), 15 deletions(-)
diff --git a/gcc/config/rs6000/aix.h b/gcc/config/rs6000/aix.h
index edd6fdb0ec2..9cff6a67e1c 100644
--- a/gcc/config/rs6000/aix.h
+++ b/gcc/config/rs6000/aix.h
@@ -280,3 +280,24 @@
/* Use standard DWARF numbering for DWARF debugging information. */
#define RS6000_USE_DWARF_NUMBERING
+/* Threaded programs must be able to fallback on pthread FAT library
+ if their architecture directory isn't present. This is happening
+ when a 32bit program built with a 64-bit gcc is running on a 32bit
+ runtime. */
+#define MULTILIB_FALLBACK(CURR_MULTILIB) \
+ do \
+ { \
+ if (!strcmp (CURR_MULTILIB, "pthread/ppc64") \
+ || !(strcmp (CURR_MULTILIB, "pthread/ppc32"))) \
+ { \
+ free (CONST_CAST (char *, CURR_MULTILIB)); \
+ CURR_MULTILIB = XNEWVEC (char, strlen ("pthread") + 1); \
+ strcpy (CURR_MULTILIB, "pthread"); \
+ } \
+ else \
+ { \
+ free (CONST_CAST (char *, CURR_MULTILIB)); \
+ CURR_MULTILIB = NULL; \
+ } \
+ } \
+ while (0)
diff --git a/gcc/gcc.c b/gcc/gcc.c
index ff7b6c4a320..6bee64dbec9 100644
--- a/gcc/gcc.c
+++ b/gcc/gcc.c
@@ -2683,11 +2683,12 @@ clear_failure_queue (void)
/* Call CALLBACK for each path in PATHS, breaking out early if CALLBACK
returns non-NULL.
- If DO_MULTI is true iterate over the paths twice, first with multilib
- suffix then without, otherwise iterate over the paths once without
- adding a multilib suffix. When DO_MULTI is true, some attempt is made
- to avoid visiting the same path twice, but we could do better. For
- instance, /usr/lib/../lib is considered different from /usr/lib.
+ If DO_MULTI is true iterate over the paths at least twice, first with
+ multilib suffixes then without any, otherwise iterate over the paths
+ once without adding a multilib suffix. When DO_MULTI is true, some
+ attempt is made to avoid visiting the same path twice, but we could
+ do better. For instance, /usr/lib/../lib is considered different
+ from /usr/lib.
At least EXTRA_SPACE chars past the end of the path passed to
CALLBACK are available for use by the callback.
CALLBACK_INFO allows extra parameters to be passed to CALLBACK.
@@ -2712,11 +2713,18 @@ for_each_path (const struct path_prefix *paths,
bool skip_multi_dir = false;
bool skip_multi_os_dir = false;
+ char *curr_multilib_dir = NULL;
+ if (do_multi && multilib_dir)
+ {
+ curr_multilib_dir = XNEWVEC (char, strlen (multilib_dir));
+ strcpy (curr_multilib_dir, multilib_dir);
+ }
+
multi_suffix = machine_suffix;
just_multi_suffix = just_machine_suffix;
- if (do_multi && multilib_dir && strcmp (multilib_dir, ".") != 0)
+ if (do_multi && curr_multilib_dir && strcmp (curr_multilib_dir, ".") != 0)
{
- multi_dir = concat (multilib_dir, dir_separator_str, NULL);
+ multi_dir = concat (curr_multilib_dir, dir_separator_str, NULL);
multi_suffix = concat (multi_suffix, multi_dir, NULL);
just_multi_suffix = concat (just_multi_suffix, multi_dir, NULL);
}
@@ -2819,17 +2827,39 @@ for_each_path (const struct path_prefix *paths,
if (multi_dir == NULL && multi_os_dir == NULL)
break;
- /* Run through the paths again, this time without multilibs.
+ /* Run through the paths again, this time with a new
+ multilib suffix or without any.
Don't repeat any we have already seen. */
if (multi_dir)
{
- free (CONST_CAST (char *, multi_dir));
- multi_dir = NULL;
- free (CONST_CAST (char *, multi_suffix));
- multi_suffix = machine_suffix;
- free (CONST_CAST (char *, just_multi_suffix));
- just_multi_suffix = just_machine_suffix;
- }
+
+#ifdef MULTILIB_FALLBACK
+ /* Retrieve the next multilib to be tried. */
+ if (curr_multilib_dir)
+ MULTILIB_FALLBACK (curr_multilib_dir);
+#else
+ free (curr_multilib_dir);
+ curr_multilib_dir = NULL;
+#endif
+ if (curr_multilib_dir)
+ {
+ free (CONST_CAST (char *, multi_dir));
+ multi_dir = concat (curr_multilib_dir, dir_separator_str, NULL);
+ free (CONST_CAST (char *, multi_suffix));
+ multi_suffix = concat (machine_suffix, multi_dir, NULL);
+ free (CONST_CAST (char *, just_multi_suffix));
+ just_multi_suffix = concat (just_machine_suffix, multi_dir, NULL);
+ }
+ else
+ {
+ free (CONST_CAST (char *, multi_dir));
+ multi_dir = NULL;
+ free (CONST_CAST (char *, multi_suffix));
+ multi_suffix = machine_suffix;
+ free (CONST_CAST (char *, just_multi_suffix));
+ just_multi_suffix = just_machine_suffix;
+ }
+ }
else
skip_multi_dir = true;
if (multi_os_dir)
--
2.25.1
