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| author | Eric Botcazou <ebotcazou@adacore.com> | 2021-05-26 19:12:05 +0200 |
|---|---|---|
| committer | Eric Botcazou <ebotcazou@adacore.com> | 2021-05-26 19:13:56 +0200 |
| commit | 401bd4adcfda9965363b1ac3ba7e1580f15d6883 (patch) | |
| tree | c71b1e857c1b29bbf42ae593ede1de9fa560e61a /gcc/c | |
| parent | 0e1fd432e9cd5a2a4703c9ef9cc61255ea22cc49 (diff) | |
| download | gcc-401bd4adcfda9965363b1ac3ba7e1580f15d6883.zip gcc-401bd4adcfda9965363b1ac3ba7e1580f15d6883.tar.gz gcc-401bd4adcfda9965363b1ac3ba7e1580f15d6883.tar.bz2 | |
Warn on type punning that toggles scalar storage order
As documented in the manual, we do not support type punning that toggles
the scalar storage order, so this adds a warning for the case of unions.
gcc/c/
PR c/100653
* c-decl.c (finish_struct): Warn for a union containing an aggregate
field with a differing scalar storage order.
gcc/testsuite/
* gcc.dg/sso-13.c: New test.
Diffstat (limited to 'gcc/c')
| -rw-r--r-- | gcc/c/c-decl.c | 7 |
1 files changed, 7 insertions, 0 deletions
diff --git a/gcc/c/c-decl.c b/gcc/c/c-decl.c index 53b2b5b..3c7b306 100644 --- a/gcc/c/c-decl.c +++ b/gcc/c/c-decl.c @@ -8853,6 +8853,13 @@ finish_struct (location_t loc, tree t, tree fieldlist, tree attributes, = c_build_qualified_type (fmain_type, TYPE_QUALS (ftype)); } } + + if (TREE_CODE (t) == UNION_TYPE + && AGGREGATE_TYPE_P (TREE_TYPE (field)) + && TYPE_REVERSE_STORAGE_ORDER (t) + != TYPE_REVERSE_STORAGE_ORDER (TREE_TYPE (field))) + warning_at (DECL_SOURCE_LOCATION (field), OPT_Wscalar_storage_order, + "type punning toggles scalar storage order"); } /* Now we have the truly final field list. |