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| author | Martin Uecker <uecker@tugraz.at> | 2024-06-23 23:14:33 +0200 |
|---|---|---|
| committer | Martin Uecker <uecker@gcc.gnu.org> | 2024-08-02 10:56:12 +0200 |
| commit | 4b9ba9cee9511930411b7b53e1333e1b6b93078d (patch) | |
| tree | 4290507da09807432ad5bf34c177834c964e5f5c /gcc/c/c-decl.cc | |
| parent | 1fbce3252bc00b1678cdf62b8798a94962e99f76 (diff) | |
| download | gcc-4b9ba9cee9511930411b7b53e1333e1b6b93078d.zip gcc-4b9ba9cee9511930411b7b53e1333e1b6b93078d.tar.gz gcc-4b9ba9cee9511930411b7b53e1333e1b6b93078d.tar.bz2 | |
c: Add support for byte arrays in C2Y
To get correct aliasing behavior requires that structures and unions
that contain a byte array, i.e. an array of non-atomic character
type (N3254), are marked with TYPE_TYPELESS_STORAGE. This change
affects also earlier language modes.
gcc/c/
* c-decl.cc (grokdeclarator, finish_struct): Set and
propagate TYPE_TYPELESS_STORAGE.
gcc/testsuite/
* gcc.dg/c2y-byte-alias-1.c: New test.
* gcc.dg/c2y-byte-alias-2.c: New test.
* gcc.dg/c2y-byte-alias-3.c: New test.
Diffstat (limited to 'gcc/c/c-decl.cc')
| -rw-r--r-- | gcc/c/c-decl.cc | 15 |
1 files changed, 13 insertions, 2 deletions
diff --git a/gcc/c/c-decl.cc b/gcc/c/c-decl.cc index 97f1d346..8cef8f2 100644 --- a/gcc/c/c-decl.cc +++ b/gcc/c/c-decl.cc @@ -7502,12 +7502,18 @@ grokdeclarator (const struct c_declarator *declarator, modify the shared type, so we gcc_assert (itype) below. */ { + /* Identify typeless storage as introduced in C2Y + and supported also in earlier language modes. */ + bool typeless = (char_type_p (type) + && !(type_quals & TYPE_QUAL_ATOMIC)) + || (AGGREGATE_TYPE_P (type) + && TYPE_TYPELESS_STORAGE (type)); + addr_space_t as = DECODE_QUAL_ADDR_SPACE (type_quals); if (!ADDR_SPACE_GENERIC_P (as) && as != TYPE_ADDR_SPACE (type)) type = build_qualified_type (type, ENCODE_QUAL_ADDR_SPACE (as)); - - type = build_array_type (type, itype); + type = build_array_type (type, itype, typeless); } if (type != error_mark_node) @@ -9659,6 +9665,10 @@ finish_struct (location_t loc, tree t, tree fieldlist, tree attributes, if (DECL_NAME (x) || RECORD_OR_UNION_TYPE_P (TREE_TYPE (x))) saw_named_field = true; + + if (AGGREGATE_TYPE_P (TREE_TYPE (x)) + && TYPE_TYPELESS_STORAGE (TREE_TYPE (x))) + TYPE_TYPELESS_STORAGE (t) = true; } detect_field_duplicates (fieldlist); @@ -9859,6 +9869,7 @@ finish_struct (location_t loc, tree t, tree fieldlist, tree attributes, TYPE_FIELDS (x) = TYPE_FIELDS (t); TYPE_LANG_SPECIFIC (x) = TYPE_LANG_SPECIFIC (t); TYPE_TRANSPARENT_AGGR (x) = TYPE_TRANSPARENT_AGGR (t); + TYPE_TYPELESS_STORAGE (x) = TYPE_TYPELESS_STORAGE (t); C_TYPE_FIELDS_READONLY (x) = C_TYPE_FIELDS_READONLY (t); C_TYPE_FIELDS_VOLATILE (x) = C_TYPE_FIELDS_VOLATILE (t); C_TYPE_FIELDS_NON_CONSTEXPR (x) = C_TYPE_FIELDS_NON_CONSTEXPR (t); |