This adjusts the type adjustment code for array components in the C and C++
front-ends as per Joseph's remark, fixes a couple of documentation glitches
and adds 3 more testcases following Richard's questions.
Joseph, is that what you had in mind?
Tested on x86_64-suse-linux.
* doc/extend.texi (scalar_storage_order): Move around and fix glitches.
c-family/
* c-common.c (c_common_attributes): Move scalar_storage_order around.
(handle_scalar_storage_order_attribute): Move around.
c/
* c-decl.c (finish_struct): Properly rewrite the type of array fields.
cp/
* class.c (finish_struct_1): Likewise.
testsuite/
* c-c++-common/sso-2.c: New test.
* c-c++-common/sso-3.c: Likewise.
* c-c++-common/sso-4.c: Likewise.
--
Eric BotcazouIndex: doc/extend.texi
===================================================================
--- doc/extend.texi (revision 224467)
+++ doc/extend.texi (working copy)
@@ -6064,53 +6064,6 @@ S *p = (S *)malloc (sizeof(S) + 100);
p->data[10] = 0; //OK
@end smallexample
-@item scalar_storage_order
-@itemx scalar_storage_order ("@var{endianness}")
-@cindex @code{scalar_storage_order} type attribute
-When attached to a @code{union} or a @code{struct}, this attribute sets
-the storage order, aka endianness, of the scalar fields of the type, as
-well as the array fields whose component is scalar. The supported
-endianness are @code{big-endian} and @code{little-endian}. The attribute
-has no effects on fields which are themselves a @code{union}, a @code{struct}
-or an array whose component is a @code{union} or a @code{struct}, and it is
-possible to have fields with a different scalar storage order than the
-enclosing type.
-
-This attribute is supported only for targets that use a uniform default
-scalar storage order (fortunately, most of them), i.e. targets that store
-the scalars either all in big-endian or all in little-endian.
-
-Additional restrictions are enforced for types with the reverse scalar
-storage order with regard to the scalar storage order of the target:
-
-@itemize
-@item Taking the address of a scalar field of a @code{union} or a
-@code{struct} with reverse scalar storage order is illegal and will
-yield an error
-@item Taking the address of an array field, whose component is scalar, of
-a @code{union} or a @code{struct} with reverse scalar storage order is
-permitted but will yield a warning, unless @option{-Wno-scalar-storage-order}
-is specified
-@item Taking the address of a @code{union} or a @code{struct} with reverse
-scalar storage order is permitted
-@end itemize
-
-These restrictions exist because the storage order attribute is lost when
-the address of a scalar or the address of an array with scalar component
-is taken, so storing indirectly through this address will generally not work.
-The second case is nevertheless allowed to be able to perform a block copy
-from or to the array.
-
-@item unused
-@cindex @code{unused} type attribute
-When attached to a type (including a @code{union} or a @code{struct}),
-this attribute means that variables of that type are meant to appear
-possibly unused. GCC does not produce a warning for any variables of
-that type, even if the variable appears to do nothing. This is often
-the case with lock or thread classes, which are usually defined and then
-not referenced, but contain constructors and destructors that have
-nontrivial bookkeeping functions.
-
@item deprecated
@itemx deprecated (@var{msg})
@cindex @code{deprecated} type attribute
@@ -6205,6 +6158,42 @@ of the structure or union is placed to m
attached to an @code{enum} definition, it indicates that the smallest
integral type should be used.
+@item scalar_storage_order ("@var{endianness}")
+@cindex @code{scalar_storage_order} type attribute
+When attached to a @code{union} or a @code{struct}, this attribute sets
+the storage order, aka endianness, of the scalar fields of the type, as
+well as the array fields whose component is scalar. The supported
+endianness are @code{big-endian} and @code{little-endian}. The attribute
+has no effects on fields which are themselves a @code{union}, a @code{struct}
+or an array whose component is a @code{union} or a @code{struct}, and it is
+possible to have fields with a different scalar storage order than the
+enclosing type.
+
+This attribute is supported only for targets that use a uniform default
+scalar storage order (fortunately, most of them), i.e. targets that store
+the scalars either all in big-endian or all in little-endian.
+
+Additional restrictions are enforced for types with the reverse scalar
+storage order with regard to the scalar storage order of the target:
+
+@itemize
+@item Taking the address of a scalar field of a @code{union} or a
+@code{struct} with reverse scalar storage order is not permitted and will
+yield an error
+@item Taking the address of an array field, whose component is scalar, of
+a @code{union} or a @code{struct} with reverse scalar storage order is
+permitted but will yield a warning, unless @option{-Wno-scalar-storage-order}
+is specified
+@item Taking the address of a @code{union} or a @code{struct} with reverse
+scalar storage order is permitted
+@end itemize
+
+These restrictions exist because the storage order attribute is lost when
+the address of a scalar or the address of an array with scalar component
+is taken, so storing indirectly through this address will generally not work.
+The second case is nevertheless allowed to be able to perform a block copy
+from or to the array.
+
@item transparent_union
@cindex @code{transparent_union} type attribute
Index: c-family/c-common.c
===================================================================
--- c-family/c-common.c (revision 224467)
+++ c-family/c-common.c (working copy)
@@ -690,10 +690,10 @@ const struct attribute_spec c_common_att
/* The same comments as for noreturn attributes apply to const ones. */
{ "const", 0, 0, true, false, false,
handle_const_attribute, false },
- { "transparent_union", 0, 0, false, false, false,
- handle_transparent_union_attribute, false },
{ "scalar_storage_order", 1, 1, false, false, false,
handle_scalar_storage_order_attribute, false },
+ { "transparent_union", 0, 0, false, false, false,
+ handle_transparent_union_attribute, false },
{ "constructor", 0, 1, true, false, false,
handle_constructor_attribute, false },
{ "destructor", 0, 1, true, false, false,
@@ -7494,6 +7494,55 @@ handle_const_attribute (tree *node, tree
return NULL_TREE;
}
+/* Handle a "scalar_storage_order" attribute; arguments as in
+ struct attribute_spec.handler. */
+
+static tree
+handle_scalar_storage_order_attribute (tree *node, tree name, tree args,
+ int flags, bool *no_add_attrs)
+{
+ tree id = TREE_VALUE (args);
+ tree type;
+
+ *no_add_attrs = true;
+
+ if (TREE_CODE (*node) == TYPE_DECL
+ && ! (flags & ATTR_FLAG_CXX11))
+ node = &TREE_TYPE (*node);
+ type = *node;
+
+ if (BYTES_BIG_ENDIAN != WORDS_BIG_ENDIAN)
+ error ("scalar_storage_order is not supported");
+
+ if (RECORD_OR_UNION_TYPE_P (type))
+ {
+ if (!(flags & (int) ATTR_FLAG_TYPE_IN_PLACE))
+ goto ignored;
+
+ if (TREE_CODE (id) == STRING_CST
+ && strcmp (TREE_STRING_POINTER (id), "big-endian") == 0)
+ {
+ if (!BYTES_BIG_ENDIAN)
+ TYPE_REVERSE_STORAGE_ORDER (type) = 1;
+ }
+ else if (TREE_CODE (id) == STRING_CST
+ && strcmp (TREE_STRING_POINTER (id), "little-endian") == 0)
+ {
+ if (BYTES_BIG_ENDIAN)
+ TYPE_REVERSE_STORAGE_ORDER (type) = 1;
+ }
+ else
+ error ("scalar_storage_order argument must be one of \"big-endian\" "
+ "or \"little-endian\"");
+
+ return NULL_TREE;
+ }
+
+ ignored:
+ warning (OPT_Wattributes, "%qE attribute ignored", name);
+ return NULL_TREE;
+}
+
/* Handle a "transparent_union" attribute; arguments as in
struct attribute_spec.handler. */
@@ -7545,55 +7594,6 @@ handle_transparent_union_attribute (tree
return NULL_TREE;
}
- ignored:
- warning (OPT_Wattributes, "%qE attribute ignored", name);
- return NULL_TREE;
-}
-
-/* Handle a "scalar_storage_order" attribute; arguments as in
- struct attribute_spec.handler. */
-
-static tree
-handle_scalar_storage_order_attribute (tree *node, tree name, tree args,
- int flags, bool *no_add_attrs)
-{
- tree id = TREE_VALUE (args);
- tree type;
-
- *no_add_attrs = true;
-
- if (TREE_CODE (*node) == TYPE_DECL
- && ! (flags & ATTR_FLAG_CXX11))
- node = &TREE_TYPE (*node);
- type = *node;
-
- if (BYTES_BIG_ENDIAN != WORDS_BIG_ENDIAN)
- error ("scalar_storage_order is not supported");
-
- if (RECORD_OR_UNION_TYPE_P (type))
- {
- if (!(flags & (int) ATTR_FLAG_TYPE_IN_PLACE))
- goto ignored;
-
- if (TREE_CODE (id) == STRING_CST
- && strcmp (TREE_STRING_POINTER (id), "big-endian") == 0)
- {
- if (!BYTES_BIG_ENDIAN)
- TYPE_REVERSE_STORAGE_ORDER (type) = 1;
- }
- else if (TREE_CODE (id) == STRING_CST
- && strcmp (TREE_STRING_POINTER (id), "little-endian") == 0)
- {
- if (BYTES_BIG_ENDIAN)
- TYPE_REVERSE_STORAGE_ORDER (type) = 1;
- }
- else
- error ("scalar_storage_order argument must be one of \"big-endian\" "
- "or \"little-endian\"");
-
- return NULL_TREE;
- }
-
ignored:
warning (OPT_Wattributes, "%qE attribute ignored", name);
return NULL_TREE;
Index: c/c-decl.c
===================================================================
--- c/c-decl.c (revision 224467)
+++ c/c-decl.c (working copy)
@@ -7733,7 +7733,7 @@ finish_struct (location_t loc, tree t, t
error ("type %qT is too large", t);
/* Give bit-fields their proper types and rewrite the type of array fields
- if the enclosing type has reverse storage order. */
+ with scalar component if the enclosing type has reverse storage order. */
for (tree field = fieldlist; field; field = DECL_CHAIN (field))
{
if (TREE_CODE (field) == FIELD_DECL
@@ -7756,17 +7756,17 @@ finish_struct (location_t loc, tree t, t
&& TREE_CODE (TREE_TYPE (field)) == ARRAY_TYPE)
{
tree ftype = TREE_TYPE (field);
- do
- ftype = TREE_TYPE (ftype);
- while (TREE_CODE (ftype) == ARRAY_TYPE);
- if (!RECORD_OR_UNION_TYPE_P (ftype))
+ if (!RECORD_OR_UNION_TYPE_P (strip_array_types (ftype)))
{
- tree *ftypep = &TREE_TYPE (field);
+ tree fmain_type = TYPE_MAIN_VARIANT (ftype);
+ tree *typep = &fmain_type;
do {
- *ftypep = build_distinct_type_copy (*ftypep);
- TYPE_REVERSE_STORAGE_ORDER (*ftypep) = 1;
- ftypep = &TREE_TYPE (*ftypep);
- } while (TREE_CODE (*ftypep) == ARRAY_TYPE);
+ *typep = build_distinct_type_copy (*typep);
+ TYPE_REVERSE_STORAGE_ORDER (*typep) = 1;
+ typep = &TREE_TYPE (*typep);
+ } while (TREE_CODE (*typep) == ARRAY_TYPE);
+ TREE_TYPE (field)
+ = c_build_qualified_type (fmain_type, TYPE_QUALS (ftype));
}
}
}
Index: testsuite/c-c++-common/sso-2.c
===================================================================
--- testsuite/c-c++-common/sso-2.c (revision 0)
+++ testsuite/c-c++-common/sso-2.c (revision 0)
@@ -0,0 +1,94 @@
+/* Test support of scalar_storage_order attribute */
+
+/* { dg-do compile } */
+
+struct S1
+{
+ int i;
+} __attribute__((scalar_storage_order("big-endian")));
+
+struct S2
+{
+ int i;
+} __attribute__((scalar_storage_order("little-endian")));
+
+struct S3 { int i; } __attribute__((scalar_storage_order("other"))); /* { dg-error "must be one of .big-endian. or .little-endian." } */
+
+void incompatible_assign (struct S1 *s1, struct S2 *s2)
+{
+ *s1 = *s2; /* { dg-error "(incompatible types|no match)" } */
+}
+
+int *addr1 (int which, struct S1 *s1, struct S2 *s2)
+{
+ return (which == 1 ? &s1->i : &s2->i); /* { dg-error "address of scalar with reverse storage order" } */
+}
+
+struct S4
+{
+ int a[4];
+ struct S2 s2;
+} __attribute__((scalar_storage_order("big-endian")));
+
+struct S5
+{
+ int a[4];
+ struct S1 s1;
+} __attribute__((scalar_storage_order("little-endian")));
+
+void *addr2 (int which, struct S4 *s4, struct S5 *s5)
+{
+ return (which == 1 ? (void *)s4->a : (void *)s5->a); /* { dg-warning "address of array with reverse scalar storage order" } */
+}
+
+void *addr3 (int which, struct S4 *s4, struct S5 *s5)
+{
+ return (which == 1 ? (void *)&s4->a : (void *)&s5->a); /* { dg-warning "address of array with reverse scalar storage order" } */
+}
+
+void *addr4 (int which, struct S4 *s4, struct S5 *s5)
+{
+ return (which == 1 ? (void *)&s4->a[0] : (void *)&s5->a[0]); /* { dg-error "address of scalar with reverse storage order" } */
+}
+
+void *addr5 (int which, struct S4 *s4, struct S5 *s5)
+{
+ return (which == 1 ? (void *)&s4->s2 : (void *) &s5->s1); /* ok */
+}
+
+struct S6
+{
+ int a[4][2];
+ struct S2 s2[2];
+} __attribute__((scalar_storage_order("big-endian")));
+
+struct S7
+{
+ int a[4][2];
+ struct S1 s1[2];
+} __attribute__((scalar_storage_order("little-endian")));
+
+void *addr6 (int which, struct S6 *s6, struct S7 *s7)
+{
+ return (which == 1 ? (void *)s6->a : (void *)s7->a); /* { dg-warning "address of array with reverse scalar storage order" } */
+}
+
+void *addr7 (int which, struct S6 *s6, struct S7 *s7)
+{
+ return (which == 1 ? (void *)&s6->a : (void *)&s7->a); /* { dg-warning "address of array with reverse scalar storage order" } */
+}
+
+void *addr8 (int which, struct S6 *s6, struct S7 *s7)
+{
+ return (which == 1 ? (void *)&s6->a[0] : (void *)&s7->a[0]); /* { dg-warning "address of array with reverse scalar storage order" } */
+}
+
+void *addr9 (int which, struct S6 *s6, struct S7 *s7)
+{
+ return (which == 1 ? (void *)&s6->a[0][0] : (void *)&s7->a[0][0]); /* { dg-error "address of scalar with reverse storage order" } */
+}
+
+void *addr10 (int which, struct S6 *s6, struct S7 *s7)
+{
+ return (which == 1 ? (void *)&s6->s2 : (void *)&s7->s1); /* ok */
+}
Index: testsuite/c-c++-common/sso-3.c
===================================================================
--- testsuite/c-c++-common/sso-3.c (revision 0)
+++ testsuite/c-c++-common/sso-3.c (revision 0)
@@ -0,0 +1,21 @@
+/* Test support of scalar_storage_order attribute */
+
+/* { dg-do compile } */
+
+struct S1
+{
+ int i;
+};
+
+typedef struct S1 __attribute__((scalar_storage_order("big-endian"))) NS1; /* { dg-warning "attribute ignored" } */
+
+struct S2
+{
+ int i;
+};
+
+typedef struct S2 __attribute__((scalar_storage_order("little-endian"))) NS2; /* { dg-warning "attribute ignored" } */
+
+struct S3 { int i; };
+
+typedef struct S3 __attribute__((scalar_storage_order("other"))) NS3; /* { dg-warning "attribute ignored" } */
Index: testsuite/c-c++-common/sso-4.c
===================================================================
--- testsuite/c-c++-common/sso-4.c (revision 0)
+++ testsuite/c-c++-common/sso-4.c (revision 0)
@@ -0,0 +1,24 @@
+/* Test support of scalar_storage_order attribute */
+
+/* { dg-do compile } */
+
+struct S3
+{
+ struct __attribute__((scalar_storage_order("big-endian"))) S1
+ {
+ int i;
+ } s1;
+};
+
+struct S4
+{
+ struct __attribute__((scalar_storage_order("little-endian"))) S2
+ {
+ int i;
+ } s2;
+};
+
+void incompatible_assign (struct S3 *s3, struct S4 *s4)
+{
+ s3->s1 = s4->s2; /* { dg-error "(incompatible types|no match)" } */
+}
Index: testsuite/c-c++-common/sso-1.c
===================================================================
--- testsuite/c-c++-common/sso-1.c (revision 224463)
+++ testsuite/c-c++-common/sso-1.c (working copy)
@@ -12,7 +12,7 @@ struct __attribute__((scalar_storage_ord
int i;
};
-struct __attribute__((scalar_storage_order("other"))) S3 {}; /* { dg-error "must be one of .big-endian. or .little-endian." } */
+struct __attribute__((scalar_storage_order("other"))) S3 { int i; }; /* { dg-error "must be one of .big-endian. or .little-endian." } */
void incompatible_assign (struct S1 *s1, struct S2 *s2)
{
Index: cp/class.c
===================================================================
--- cp/class.c (revision 224467)
+++ cp/class.c (working copy)
@@ -6658,7 +6658,8 @@ finish_struct_1 (tree t)
set_method_tm_attributes (t);
/* Complete the rtl for any static member objects of the type we're
- working on. */
+ working on and rewrite the type of array fields with scalar
+ component if the enclosing type has reverse storage order. */
for (x = TYPE_FIELDS (t); x; x = DECL_CHAIN (x))
if (VAR_P (x) && TREE_STATIC (x)
&& TREE_TYPE (x) != error_mark_node
@@ -6669,17 +6670,17 @@ finish_struct_1 (tree t)
&& TREE_CODE (TREE_TYPE (x)) == ARRAY_TYPE)
{
tree ftype = TREE_TYPE (x);
- do
- ftype = TREE_TYPE (ftype);
- while (TREE_CODE (ftype) == ARRAY_TYPE);
- if (!RECORD_OR_UNION_TYPE_P (ftype))
+ if (!RECORD_OR_UNION_TYPE_P (strip_array_types (ftype)))
{
- tree *ftypep = &TREE_TYPE (x);
+ tree fmain_type = TYPE_MAIN_VARIANT (ftype);
+ tree *typep = &fmain_type;
do {
- *ftypep = build_distinct_type_copy (*ftypep);
- TYPE_REVERSE_STORAGE_ORDER (*ftypep) = 1;
- ftypep = &TREE_TYPE (*ftypep);
- } while (TREE_CODE (*ftypep) == ARRAY_TYPE);
+ *typep = build_distinct_type_copy (*typep);
+ TYPE_REVERSE_STORAGE_ORDER (*typep) = 1;
+ typep = &TREE_TYPE (*typep);
+ } while (TREE_CODE (*typep) == ARRAY_TYPE);
+ TREE_TYPE (x)
+ = cp_build_qualified_type (fmain_type, TYPE_QUALS (ftype));
}
}
