scripts/gcc-plugins/randomize_layout_plugin.c | 16 +++------------- 1 file changed, 3 insertions(+), 13 deletions(-)
Replace the original swapping logic with swap() to improve readability and
remove temporary variables
Signed-off-by: Liao Yuanhong <liaoyuanhong@vivo.com>
---
scripts/gcc-plugins/randomize_layout_plugin.c | 16 +++-------------
1 file changed, 3 insertions(+), 13 deletions(-)
diff --git a/scripts/gcc-plugins/randomize_layout_plugin.c b/scripts/gcc-plugins/randomize_layout_plugin.c
index ff65a4f87f24..5d6ebe292cbf 100644
--- a/scripts/gcc-plugins/randomize_layout_plugin.c
+++ b/scripts/gcc-plugins/randomize_layout_plugin.c
@@ -199,17 +199,12 @@ static void performance_shuffle(tree *newtree, unsigned long length, ranctx *prn
/* FIXME: this group shuffle is currently a no-op. */
for (i = num_groups - 1; i > 0; i--) {
- struct partition_group tmp;
randnum = ranval(prng_state) % (i + 1);
- tmp = size_group[i];
- size_group[i] = size_group[randnum];
- size_group[randnum] = tmp;
+ swap(size_group[randnum], size_group[i]);
}
for (x = 0; x < num_groups; x++) {
for (index = size_group[x].length - 1; index > 0; index--) {
- tree tmp;
-
i = size_group[x].start + index;
if (DECL_BIT_FIELD_TYPE(newtree[i]))
continue;
@@ -218,9 +213,7 @@ static void performance_shuffle(tree *newtree, unsigned long length, ranctx *prn
// we could handle this case differently if desired
if (DECL_BIT_FIELD_TYPE(newtree[randnum]))
continue;
- tmp = newtree[i];
- newtree[i] = newtree[randnum];
- newtree[randnum] = tmp;
+ swap(newtree[randnum], newtree[i]);
}
}
}
@@ -230,11 +223,8 @@ static void full_shuffle(tree *newtree, unsigned long length, ranctx *prng_state
unsigned long i, randnum;
for (i = length - 1; i > 0; i--) {
- tree tmp;
randnum = ranval(prng_state) % (i + 1);
- tmp = newtree[i];
- newtree[i] = newtree[randnum];
- newtree[randnum] = tmp;
+ swap(newtree[randnum], newtree[i]);
}
}
--
2.34.1Hi Liao,
kernel test robot noticed the following build errors:
[auto build test ERROR on kees/for-next/hardening]
[also build test ERROR on kees/for-next/kspp kees/for-next/pstore linus/master v6.16 next-20250806]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch#_base_tree_information]
url: https://github.com/intel-lab-lkp/linux/commits/Liao-Yuanhong/gcc-plugins-Use-swap-to-simplify-code/20250806-204609
base: https://git.kernel.org/pub/scm/linux/kernel/git/kees/linux.git for-next/hardening
patch link: https://lore.kernel.org/r/20250806124341.382446-1-liaoyuanhong%40vivo.com
patch subject: [PATCH] gcc-plugins: Use swap() to simplify code
config: i386-randconfig-012-20250807 (https://download.01.org/0day-ci/archive/20250807/202508071233.Bf6EgGd2-lkp@intel.com/config)
compiler: gcc-12 (Debian 12.2.0-14+deb12u1) 12.2.0
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20250807/202508071233.Bf6EgGd2-lkp@intel.com/reproduce)
If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202508071233.Bf6EgGd2-lkp@intel.com/
All errors (new ones prefixed by >>):
scripts/gcc-plugins/randomize_layout_plugin.c: In function 'void performance_shuffle(tree_node**, long unsigned int, ranctx*)':
>> scripts/gcc-plugins/randomize_layout_plugin.c:203:17: error: 'swap' was not declared in this scope
203 | swap(size_group[randnum], size_group[i]);
| ^~~~
scripts/gcc-plugins/randomize_layout_plugin.c:203:17: note: suggested alternatives:
In file included from /usr/include/c++/12/utility:69,
from /usr/lib/gcc/x86_64-linux-gnu/12/plugin/include/system.h:244,
from /usr/lib/gcc/x86_64-linux-gnu/12/plugin/include/gcc-plugin.h:28,
from scripts/gcc-plugins/gcc-common.h:6,
from scripts/gcc-plugins/randomize_layout_plugin.c:19:
/usr/include/c++/12/bits/stl_pair.h:715:5: note: 'std::swap'
715 | swap(pair<_T1, _T2>&, pair<_T1, _T2>&) = delete;
| ^~~~
In file included from /usr/include/c++/12/bits/stl_pair.h:61:
/usr/include/c++/12/bits/move.h:196:5: note: 'std::swap'
196 | swap(_Tp& __a, _Tp& __b)
| ^~~~
/usr/include/c++/12/bits/move.h:196:5: note: 'std::swap'
scripts/gcc-plugins/randomize_layout_plugin.c:216:25: error: 'swap' was not declared in this scope
216 | swap(newtree[randnum], newtree[i]);
| ^~~~
scripts/gcc-plugins/randomize_layout_plugin.c:216:25: note: suggested alternatives:
/usr/include/c++/12/bits/stl_pair.h:715:5: note: 'std::swap'
715 | swap(pair<_T1, _T2>&, pair<_T1, _T2>&) = delete;
| ^~~~
/usr/include/c++/12/bits/move.h:196:5: note: 'std::swap'
196 | swap(_Tp& __a, _Tp& __b)
| ^~~~
/usr/include/c++/12/bits/move.h:196:5: note: 'std::swap'
scripts/gcc-plugins/randomize_layout_plugin.c: In function 'void full_shuffle(tree_node**, long unsigned int, ranctx*)':
scripts/gcc-plugins/randomize_layout_plugin.c:227:17: error: 'swap' was not declared in this scope
227 | swap(newtree[randnum], newtree[i]);
| ^~~~
scripts/gcc-plugins/randomize_layout_plugin.c:227:17: note: suggested alternatives:
/usr/include/c++/12/bits/stl_pair.h:715:5: note: 'std::swap'
715 | swap(pair<_T1, _T2>&, pair<_T1, _T2>&) = delete;
| ^~~~
/usr/include/c++/12/bits/move.h:196:5: note: 'std::swap'
196 | swap(_Tp& __a, _Tp& __b)
| ^~~~
/usr/include/c++/12/bits/move.h:196:5: note: 'std::swap'
make[4]: *** [scripts/gcc-plugins/Makefile:54: scripts/gcc-plugins/randomize_layout_plugin.so] Error 1 shuffle=2972943921
make[4]: Target 'scripts/gcc-plugins/' not remade because of errors.
make[3]: *** [scripts/Makefile.build:554: scripts/gcc-plugins] Error 2 shuffle=2972943921
make[3]: Target 'scripts/' not remade because of errors.
make[2]: *** [Makefile:1258: scripts] Error 2 shuffle=2972943921
make[2]: Target 'prepare' not remade because of errors.
make[1]: *** [Makefile:248: __sub-make] Error 2 shuffle=2972943921
make[1]: Target 'prepare' not remade because of errors.
make: *** [Makefile:248: __sub-make] Error 2 shuffle=2972943921
make: Target 'prepare' not remade because of errors.
vim +/swap +203 scripts/gcc-plugins/randomize_layout_plugin.c
190
191 static void performance_shuffle(tree *newtree, unsigned long length, ranctx *prng_state)
192 {
193 unsigned long i, x, index;
194 struct partition_group size_group[length];
195 unsigned long num_groups = 0;
196 unsigned long randnum;
197
198 partition_struct(newtree, length, (struct partition_group *)&size_group, &num_groups);
199
200 /* FIXME: this group shuffle is currently a no-op. */
201 for (i = num_groups - 1; i > 0; i--) {
202 randnum = ranval(prng_state) % (i + 1);
> 203 swap(size_group[randnum], size_group[i]);
204 }
205
206 for (x = 0; x < num_groups; x++) {
207 for (index = size_group[x].length - 1; index > 0; index--) {
208 i = size_group[x].start + index;
209 if (DECL_BIT_FIELD_TYPE(newtree[i]))
210 continue;
211 randnum = ranval(prng_state) % (index + 1);
212 randnum += size_group[x].start;
213 // we could handle this case differently if desired
214 if (DECL_BIT_FIELD_TYPE(newtree[randnum]))
215 continue;
216 swap(newtree[randnum], newtree[i]);
217 }
218 }
219 }
220
--
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