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PATCH to finish_layout/check_field_decls for c++/13983 and c++/17519
- From: Jason Merrill <jason at redhat dot com>
- To: "gcc-patches >> GCC Patches" <gcc-patches at gcc dot gnu dot org>
- Date: Wed, 05 Jul 2006 22:09:50 -0400
- Subject: PATCH to finish_layout/check_field_decls for c++/13983 and c++/17519
Both of these PRs are about check_field_decls failing to recognize that
the field type is in fact a packed non-POD type, and then complaining
that it's a uppacked non-POD type. Fixed by stripping array types
before checking TYPE_PACKED (17519) and properly copying TYPE_PACKED to
variants of class template instantiations (13983).
Tested x86_64-pc-linux-gnu, applied to trunk.
2006-07-05 Jason Merrill <jason@redhat.com>
PR c++/13983
PR c++/17519
* stor-layout.c (finish_record_layout): Copy TYPE_PACKED to variants.
* c-common.c (handle_packed_attribute): So don't copy it here.
* c-decl.c (finish_struct): Don't copy TYPE_ALIGN.
* cp/class.c (check_field_decls): Check TYPE_PACKED after
stripping array types.
(finish_struct_bits): Don't copy TYPE_SIZE here.
Index: stor-layout.c
===================================================================
*** stor-layout.c (revision 115216)
--- stor-layout.c (working copy)
*************** finalize_type_size (tree type)
*** 1465,1470 ****
--- 1465,1472 ----
void
finish_record_layout (record_layout_info rli, int free_p)
{
+ tree variant;
+
/* Compute the final size. */
finalize_record_size (rli);
*************** finish_record_layout (record_layout_info
*** 1474,1479 ****
--- 1476,1487 ----
/* Perform any last tweaks to the TYPE_SIZE, etc. */
finalize_type_size (rli->t);
+ /* Propagate TYPE_PACKED to variants. With C++ templates,
+ handle_packed_attribute is too early to do this. */
+ for (variant = TYPE_NEXT_VARIANT (rli->t); variant;
+ variant = TYPE_NEXT_VARIANT (variant))
+ TYPE_PACKED (variant) = TYPE_PACKED (rli->t);
+
/* Lay out any static members. This is done now because their type
may use the record's type. */
while (rli->pending_statics)
Index: c-common.c
===================================================================
*** c-common.c (revision 115216)
--- c-common.c (working copy)
*************** handle_packed_attribute (tree *node, tre
*** 4082,4101 ****
if (!(flags & (int) ATTR_FLAG_TYPE_IN_PLACE))
*node = build_variant_type_copy (*node);
TYPE_PACKED (*node) = 1;
- if (TYPE_MAIN_VARIANT (*node) == *node)
- {
- /* If it is the main variant, then pack the other variants
- too. This happens in,
-
- struct Foo {
- struct Foo const *ptr; // creates a variant w/o packed flag
- } __ attribute__((packed)); // packs it now.
- */
- tree probe;
-
- for (probe = *node; probe; probe = TYPE_NEXT_VARIANT (probe))
- TYPE_PACKED (probe) = 1;
- }
}
else if (TREE_CODE (*node) == FIELD_DECL)
{
--- 4082,4087 ----
Index: c-decl.c
===================================================================
*** c-decl.c (revision 115216)
--- c-decl.c (working copy)
*************** finish_struct (tree t, tree fieldlist, t
*** 5574,5581 ****
{
TYPE_FIELDS (x) = TYPE_FIELDS (t);
TYPE_LANG_SPECIFIC (x) = TYPE_LANG_SPECIFIC (t);
- TYPE_ALIGN (x) = TYPE_ALIGN (t);
- TYPE_USER_ALIGN (x) = TYPE_USER_ALIGN (t);
C_TYPE_FIELDS_READONLY (x) = C_TYPE_FIELDS_READONLY (t);
C_TYPE_FIELDS_VOLATILE (x) = C_TYPE_FIELDS_VOLATILE (t);
C_TYPE_VARIABLE_SIZE (x) = C_TYPE_VARIABLE_SIZE (t);
--- 5574,5579 ----
Index: cp/class.c
===================================================================
*** cp/class.c (revision 115216)
--- cp/class.c (working copy)
*************** finish_struct_bits (tree t)
*** 1433,1440 ****
TYPE_VFIELD (variants) = TYPE_VFIELD (t);
TYPE_METHODS (variants) = TYPE_METHODS (t);
TYPE_FIELDS (variants) = TYPE_FIELDS (t);
- TYPE_SIZE (variants) = TYPE_SIZE (t);
- TYPE_SIZE_UNIT (variants) = TYPE_SIZE_UNIT (t);
}
if (BINFO_N_BASE_BINFOS (TYPE_BINFO (t)) && TYPE_POLYMORPHIC_P (t))
--- 1433,1438 ----
*************** check_field_decls (tree t, tree *access_
*** 2815,2854 ****
next = &TREE_CHAIN (x);
- if (TREE_CODE (x) == FIELD_DECL)
- {
- if (TYPE_PACKED (t))
- {
- if (!pod_type_p (TREE_TYPE (x)) && !TYPE_PACKED (TREE_TYPE (x)))
- warning
- (0,
- "ignoring packed attribute on unpacked non-POD field %q+#D",
- x);
- else if (TYPE_ALIGN (TREE_TYPE (x)) > BITS_PER_UNIT)
- DECL_PACKED (x) = 1;
- }
-
- if (DECL_C_BIT_FIELD (x) && integer_zerop (DECL_INITIAL (x)))
- /* We don't treat zero-width bitfields as making a class
- non-empty. */
- ;
- else
- {
- tree element_type;
-
- /* The class is non-empty. */
- CLASSTYPE_EMPTY_P (t) = 0;
- /* The class is not even nearly empty. */
- CLASSTYPE_NEARLY_EMPTY_P (t) = 0;
- /* If one of the data members contains an empty class,
- so does T. */
- element_type = strip_array_types (type);
- if (CLASS_TYPE_P (element_type)
- && CLASSTYPE_CONTAINS_EMPTY_CLASS_P (element_type))
- CLASSTYPE_CONTAINS_EMPTY_CLASS_P (t) = 1;
- }
- }
-
if (TREE_CODE (x) == USING_DECL)
{
/* Prune the access declaration from the list of fields. */
--- 2813,2818 ----
*************** check_field_decls (tree t, tree *access_
*** 2945,2950 ****
--- 2909,2942 ----
type = strip_array_types (type);
+ if (TYPE_PACKED (t))
+ {
+ if (!pod_type_p (type) && !TYPE_PACKED (type))
+ warning
+ (0,
+ "ignoring packed attribute on unpacked non-POD field %q+#D",
+ x);
+ else if (TYPE_ALIGN (TREE_TYPE (x)) > BITS_PER_UNIT)
+ DECL_PACKED (x) = 1;
+ }
+
+ if (DECL_C_BIT_FIELD (x) && integer_zerop (DECL_INITIAL (x)))
+ /* We don't treat zero-width bitfields as making a class
+ non-empty. */
+ ;
+ else
+ {
+ /* The class is non-empty. */
+ CLASSTYPE_EMPTY_P (t) = 0;
+ /* The class is not even nearly empty. */
+ CLASSTYPE_NEARLY_EMPTY_P (t) = 0;
+ /* If one of the data members contains an empty class,
+ so does T. */
+ if (CLASS_TYPE_P (type)
+ && CLASSTYPE_CONTAINS_EMPTY_CLASS_P (type))
+ CLASSTYPE_CONTAINS_EMPTY_CLASS_P (t) = 1;
+ }
+
/* This is used by -Weffc++ (see below). Warn only for pointers
to members which might hold dynamic memory. So do not warn
for pointers to functions or pointers to members. */
Index: testsuite/g++.dg/ext/packed10.C
===================================================================
*** testsuite/g++.dg/ext/packed10.C (revision 0)
--- testsuite/g++.dg/ext/packed10.C (revision 0)
***************
*** 0 ****
--- 1,14 ----
+ // PR c++/13983, c++/17519
+ // The typedef and the array were causing us to miss that A<int> is
+ // a packed type.
+
+ template <class T>
+ struct A {
+ A();
+ } __attribute__((packed));
+
+ typedef A<int> Ai;
+
+ struct B {
+ Ai a[2];
+ } __attribute__((packed));