Re: [V5] [C PATCH 4/4] c23: construct composite type for tagged types

[Joseph Myers]

On Sun, 17 Dec 2023, Martin Uecker wrote:

> +   tree f = build_decl (input_location, FIELD_DECL, DECL_NAME (a),
> +composite_type_internal (ta, tb, cache));
> +
> +   DECL_PACKED (f) = DECL_PACKED (a);
> +   SET_DECL_ALIGN (f, DECL_ALIGN (a));
> +   DECL_ATTRIBUTES (f) = DECL_ATTRIBUTES (a);

grokdeclarator, as called for the original declarations of fields, also 
has logic to set DECL_NONADDRESSABLE_P (for bit-fields), DECL_PADDING_P 
(for unnamed bit-fields) and C_DECL_VARIABLE_SIZE.  I don't see anything 
that would cause these to be set appropriately for a composite type.  (The 
first two are only used in the middle-end, which might make it harder to 
test that they have the right values.)

-- 
Joseph S. Myers
jos...@codesourcery.com

[V5] [C PATCH 4/4] c23: construct composite type for tagged types

[Martin Uecker]

Support for constructing composite types for structs and unions
in C23.

gcc/c:
* c-typeck.cc (composite_type_internal): Adapted from
composite_type to support structs and unions.
(composite_type): New wrapper function.
(build_conditional_operator): Return composite type.
* c-decl.cc (finish_struct): Allow NULL for
enclosing_struct_parse_info.

gcc/testsuite:
* gcc.dg/c23-tag-alias-6.c: New test.
* gcc.dg/c23-tag-composite-1.c: New test.
* gcc.dg/c23-tag-composite-2.c: New test.
* gcc.dg/c23-tag-composite-3.c: New test.
* gcc.dg/c23-tag-composite-4.c: New test.
* gcc.dg/c23-tag-composite-5.c: New test.
* gcc.dg/c23-tag-composite-6.c: New test.
* gcc.dg/c23-tag-composite-7.c: New test.
* gcc.dg/c23-tag-composite-8.c: New test.
* gcc.dg/c23-tag-composite-9.c: New test.
* gcc.dg/gnu23-tag-composite-1.c: New test.
* gcc.dg/gnu23-tag-composite-2.c: New test.
* gcc.dg/gnu23-tag-composite-3.c: New test.
* gcc.dg/gnu23-tag-composite-4.c: New test.
---
 gcc/c/c-decl.cc  |  21 +--
 gcc/c/c-typeck.cc| 137 ---
 gcc/testsuite/gcc.dg/c23-tag-alias-6.c   |  32 +
 gcc/testsuite/gcc.dg/c23-tag-composite-1.c   |  26 
 gcc/testsuite/gcc.dg/c23-tag-composite-2.c   |  16 +++
 gcc/testsuite/gcc.dg/c23-tag-composite-3.c   |  50 +++
 gcc/testsuite/gcc.dg/c23-tag-composite-4.c   |  21 +++
 gcc/testsuite/gcc.dg/c23-tag-composite-5.c   |  25 
 gcc/testsuite/gcc.dg/c23-tag-composite-6.c   |  18 +++
 gcc/testsuite/gcc.dg/c23-tag-composite-7.c   |  20 +++
 gcc/testsuite/gcc.dg/c23-tag-composite-8.c   |  15 ++
 gcc/testsuite/gcc.dg/c23-tag-composite-9.c   |  19 +++
 gcc/testsuite/gcc.dg/gnu23-tag-composite-1.c |  45 ++
 gcc/testsuite/gcc.dg/gnu23-tag-composite-2.c |  30 
 gcc/testsuite/gcc.dg/gnu23-tag-composite-3.c |  24 
 gcc/testsuite/gcc.dg/gnu23-tag-composite-4.c |  28 
 16 files changed, 500 insertions(+), 27 deletions(-)
 create mode 100644 gcc/testsuite/gcc.dg/c23-tag-alias-6.c
 create mode 100644 gcc/testsuite/gcc.dg/c23-tag-composite-1.c
 create mode 100644 gcc/testsuite/gcc.dg/c23-tag-composite-2.c
 create mode 100644 gcc/testsuite/gcc.dg/c23-tag-composite-3.c
 create mode 100644 gcc/testsuite/gcc.dg/c23-tag-composite-4.c
 create mode 100644 gcc/testsuite/gcc.dg/c23-tag-composite-5.c
 create mode 100644 gcc/testsuite/gcc.dg/c23-tag-composite-6.c
 create mode 100644 gcc/testsuite/gcc.dg/c23-tag-composite-7.c
 create mode 100644 gcc/testsuite/gcc.dg/c23-tag-composite-8.c
 create mode 100644 gcc/testsuite/gcc.dg/c23-tag-composite-9.c
 create mode 100644 gcc/testsuite/gcc.dg/gnu23-tag-composite-1.c
 create mode 100644 gcc/testsuite/gcc.dg/gnu23-tag-composite-2.c
 create mode 100644 gcc/testsuite/gcc.dg/gnu23-tag-composite-3.c
 create mode 100644 gcc/testsuite/gcc.dg/gnu23-tag-composite-4.c

diff --git a/gcc/c/c-decl.cc b/gcc/c/c-decl.cc
index 6639ec35e5f..b72738ea04a 100644
--- a/gcc/c/c-decl.cc
+++ b/gcc/c/c-decl.cc
@@ -9674,7 +9674,7 @@ finish_struct (location_t loc, tree t, tree fieldlist, 
tree attributes,
 }
 
   /* Check for consistency with previous definition.  */
-  if (flag_isoc23)
+  if (flag_isoc23 && NULL != enclosing_struct_parse_info)
 {
   tree vistype = previous_tag (t);
   if (vistype
@@ -9744,16 +9744,19 @@ finish_struct (location_t loc, tree t, tree fieldlist, 
tree attributes,
   if (warn_cxx_compat)
 warn_cxx_compat_finish_struct (fieldlist, TREE_CODE (t), loc);
 
-  delete struct_parse_info;
+  if (NULL != enclosing_struct_parse_info)
+{
+  delete struct_parse_info;
 
-  struct_parse_info = enclosing_struct_parse_info;
+  struct_parse_info = enclosing_struct_parse_info;
 
-  /* If this struct is defined inside a struct, add it to
- struct_types.  */
-  if (warn_cxx_compat
-  && struct_parse_info != NULL
-  && !in_sizeof && !in_typeof && !in_alignof)
-struct_parse_info->struct_types.safe_push (t);
+  /* If this struct is defined inside a struct, add it to
+struct_types.  */
+  if (warn_cxx_compat
+ && struct_parse_info != NULL
+ && !in_sizeof && !in_typeof && !in_alignof)
+   struct_parse_info->struct_types.safe_push (t);
+ }
 
   return t;
 }
diff --git a/gcc/c/c-typeck.cc b/gcc/c/c-typeck.cc
index 4d3079156ba..ac31eba6e46 100644
--- a/gcc/c/c-typeck.cc
+++ b/gcc/c/c-typeck.cc
@@ -381,8 +381,15 @@ build_functype_attribute_variant (tree ntype, tree otype, 
tree attrs)
nonzero; if that isn't so, this may crash.  In particular, we
assume that qualifiers match.  */
 
+struct composite_cache {
+  tree t1;
+  tree t2;
+  tree composite;
+  struct composite_cache* next;
+};
+
 tree
-composite_type (tree t1, tree t2)
+composite_type_internal (tree t1, tree t2, struct composite_cache* cache)
 {
   enum tree_code code1;
   enum tree_code code2;
@@ -427,7