[PATCH] gcc-multilib: Simply/fix MULTILIB_OPTIONS handling

[Richard Purdie <richard.purdie@linuxfoundation.org>]

MULTILIB_OPTIONS takes the parameters which trigger a given multilib to be
selected. It supports *one* option per multilib, '/' separated. Spaces
separate options used to generate additional multilib combinations.

Adding in all of CFLAGS to this is therefore clearly a really bad idea
but how do we fix things?

The best option I've come up with so far is a list of whitelist variables
to use to trigger the multilibs. Its populated with the standard multilibs
we support, anyone setting up an advanced multilib can populate the variable
with the correct trigger parameters.

This has the advantage of simplifying the code and allowing us to remove
the code filtering blocks since there is no longer option duplication. Testing
after this change shows a much improved sdk toolchain functionality.

Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

diff --git a/meta/recipes-devtools/gcc/gcc-multilib-config.inc b/meta/recipes-devtools/gcc/gcc-multilib-config.inc
index acea6d8..b8c705a 100644
--- a/meta/recipes-devtools/gcc/gcc-multilib-config.inc
+++ b/meta/recipes-devtools/gcc/gcc-multilib-config.inc
@@ -14,6 +14,8 @@
 #    gcc/config/mips/linux64.h
 #    gcc/config/rs6000/linux64.h
 
+MULTILIB_OPTION_WHITELIST ??= "-m32 -m64 -mx32 -mabi=n32 -mabi=32 -mabi=64" 
+
 python gcc_multilib_setup() {
     import re
     import shutil
@@ -187,30 +189,19 @@ python gcc_multilib_setup() {
             bb.error('Unknown libdir (%s) of the tune : %s' % (tune_baselib, tune))
 
         # take out '-' mcpu='s and march='s from parameters
-        options.append(re.sub(r'mcpu=[^ ]+ *', '',
-                         re.sub(r'march=[^ ]+ *', '',
-                           re.sub(r' +\-+', ' ',
-                             re.sub(r'^ *\-+', '', tune_parameters['ccargs'])))))
+        opts = []
+        whitelist = (d.getVar("MULTILIB_OPTION_WHITELIST", True) or "").split()
+        for i in tune_parameters['ccargs'].split():
+            if i in whitelist:
+                opts.append(i)
+        options.append(" ".join(opts))
+
         if tune_baselib == 'lib':
             dirnames.append('32')  # /lib => 32bit lib
         else:
             dirnames.append(tune_baselib.replace('lib', ''))
         osdirnames.append('../' + tune_baselib)
 
-    if len(options) > 1:
-        for optstr in options:
-            optsets.append(optstr.split())
-
-    #get common options present in all the tune parameters
-        common_opt_set = set.intersection(*map(set, optsets))
-
-    #common options will be added at the end of the options string only once
-        if (len(common_opt_set) > 0):
-            rex = re.compile(''.join(['\\b(', '|'.join(common_opt_set), ')\\W']), re.I)
-            options = [rex.sub("", optstr) for optstr in options]
-            options = [optstr.strip() for optstr in options]
-            options[len(options)-1] = ' '.join((options[len(options)-1], ' '.join(common_opt_set)))
-
     write_config(builddir, target_config_files, options, dirnames, osdirnames)
     write_headers(builddir, header_config_files, libdir32, libdir64, libdirx32, libdirn32)
 }