Bug 26612

Summary:	visibility and ODR
Product:	gcc	Reporter:	Geoff Keating <geoffk>
Component:	c++	Assignee:	Jason Merrill <jason>
Status:	RESOLVED FIXED
Severity:	enhancement	CC:	fang, gcc-bugs, ismail, pinskia, sabre
Priority:	P3	Keywords:	visibility, wrong-code
Version:	4.2.0
Target Milestone:	4.2.0
Host:		Target:
Build:		Known to work:
Known to fail:		Last reconfirmed:	2006-04-05 22:49:27
Bug Depends on:
Bug Blocks:	19664

Description Geoff Keating 2006-03-09 00:52:44 UTC

In bug 10591, it's pointed out that you can use the ODR rules to clear the TREE_PUBLIC flag.  You can do the same thing to make something have hidden visibility even though it's not declared so.

In fact, this is a requirement.  For example, in bug 19664, I mention that if the user declares

struct mytype __attribute__((visibility(hidden))) { ... };
vector<mytype> x;

then everything to do with 'vector<mytype>' needs to be hidden, because a user could do the same thing in a different shared object with a different 'mytype'.  Likewise,

struct a_struct __attribute__((visibility(hidden)));
void foo(a_struct &) { }

Even though "foo" is not marked hidden it should still be hidden, because it
could be overloaded in a different shared object with a parameter which has
type 'a_struct &' but is a different type.

This is especially important when 'func' is 'operator ==' or similar.

Comment 1 Andrew Pinski 2006-03-09 00:54:04 UTC

Confirmed.

Comment 2 Jason Merrill 2006-04-05 22:48:37 UTC

Connected with PR 25915.

Comment 3 Jason Merrill 2006-06-30 01:16:26 UTC

Subject: Bug 26612

Author: jason
Date: Fri Jun 30 01:15:56 2006
New Revision: 115086

URL: http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=115086
Log:
        PR c++/26905
        PR c++/26612
        PR c++/27000
        PR c++/26984
        PR c++/19134
        * tree.c (build_decl_stat): Don't hande #pragma visibility here.
        * c-common.c (c_determine_visibility): Handle it here.
        * c-decl.c (finish_decl): Call c_determine_visibility for
        functions, too.
        * flags.h (enum symbol_visibility): Sort from most to least visibility.
        * tree.h: Likewise.
        * varasm.c (default_assemble_visibility): Likewise.
        * c-common.c (handle_visibility_attribute): Complain about trying
        to give visibility to an already defined class, or trying to change
        declared visibility. Always attach the attribute.
        * cp/decl2.c (determine_visibility): Overhaul.
        (determine_visibility_from_class): Likewise.
        (min_vis_r, type_visibility, constrain_visibility): New fns.
        (constrain_visibility_for_template): Likewise.
        (constrain_class_visibility): Likewise.
        * cp/decl.c (cp_finish_decl): Call determine_visibility for function
        decls, too.
        * cp/name-lookup.c (pushtag): Call determine_visibility.
        * cp/decl.c (duplicate_decls): Don't copy visibility from template to
        specialization.
        * cp/pt.c (check_explicit_specialization): Likewise.
        (lookup_template_class, tsubst_decl): Call determine_visibility.
        * cp/class.c (finish_struct_1): Call constrain_class_visibility.

        PR c++/26905
        PR c++/21675
        PR c++/17470
        * cp/parser.c (cp_parser_explicit_instantiation): Pass the attributes
        to grokdeclarator.
        (cp_parser_type_specifier): Allow 'enum __attribute ((...)) E'.
        (cp_parser_enum_specifier): Likewise.
        (cp_parser_elaborated_type_specifier): Apply attributes if this
        declares only the class.
        (cp_parser_class_specifier): Apply leading attributes immediately.
        * cp/semantics.c (begin_class_definition): Add attributes parameter,
        apply them to the type.
        * attribs.c (decl_attributes): Ignore type-in-place attributes
        once the type has been defined.

        PR c++/21581
        PR c++/25915
        * cp/tree.c (decl_anon_ns_mem_p): New function.
        * cp/cp-tree.h: Declare it.
        * cp/decl2.c (determine_visibility): Make anonymous namespace
        members static.
        (min_vis_r, constrain_visibility): Likewise.
        * cp/rtti.c (create_pseudo_type_info): Set TREE_PUBLIC on
        pseudo-types.
        * cp/decl.c (cxx_init_decl_processing): Set TREE_PUBLIC on
        global_namespace.
        * cp/name-lookup.c (push_namespace_with_attribs): Don't set TREE_PUBLIC
        on anonymous namespaces.

Added:
    trunk/gcc/testsuite/g++.dg/ext/visibility/anon2.C
    trunk/gcc/testsuite/g++.dg/ext/visibility/class1.C
    trunk/gcc/testsuite/g++.dg/ext/visibility/prop1.C
    trunk/gcc/testsuite/g++.dg/ext/visibility/redecl1.C
    trunk/gcc/testsuite/g++.dg/ext/visibility/template1.C
    trunk/gcc/testsuite/g++.dg/ext/visibility/template2.C
    trunk/gcc/testsuite/g++.dg/ext/visibility/template3.C
    trunk/gcc/testsuite/g++.dg/ext/visibility/template4.C
    trunk/gcc/testsuite/g++.dg/ext/visibility/typeinfo1.C
    trunk/gcc/testsuite/g++.dg/ext/visibility/warn1.C
    trunk/gcc/testsuite/g++.dg/ext/visibility/warn2.C
    trunk/gcc/testsuite/g++.dg/ext/visibility/warn3.C
    trunk/gcc/testsuite/g++.dg/ext/visibility/warn4.C
Modified:
    trunk/gcc/ChangeLog
    trunk/gcc/attribs.c
    trunk/gcc/c-common.c
    trunk/gcc/c-decl.c
    trunk/gcc/cp/ChangeLog
    trunk/gcc/cp/class.c
    trunk/gcc/cp/cp-tree.h
    trunk/gcc/cp/decl.c
    trunk/gcc/cp/decl2.c
    trunk/gcc/cp/name-lookup.c
    trunk/gcc/cp/parser.c
    trunk/gcc/cp/pt.c
    trunk/gcc/cp/rtti.c
    trunk/gcc/cp/semantics.c
    trunk/gcc/cp/tree.c
    trunk/gcc/doc/extend.texi
    trunk/gcc/doc/invoke.texi
    trunk/gcc/flags.h
    trunk/gcc/testsuite/g++.dg/ext/attrib14.C
    trunk/gcc/testsuite/g++.dg/ext/attrib9.C
    trunk/gcc/testsuite/g++.dg/ext/visibility/anon1.C
    trunk/gcc/testsuite/g++.dg/ext/visibility/assign1.C
    trunk/gcc/testsuite/g++.dg/ext/visibility/fvisibility-override2.C
    trunk/gcc/testsuite/g++.dg/ext/visibility/virtual.C
    trunk/gcc/testsuite/g++.old-deja/g++.pt/enum5.C
    trunk/gcc/tree.c
    trunk/gcc/tree.h
    trunk/gcc/varasm.c

Comment 4 Andrew Pinski 2006-06-30 15:31:42 UTC

Fixed.

Comment 5 Andrew Pinski 2006-06-30 15:32:17 UTC

Fixed I said :).

Comment 6 Jakub Jelinek 2006-08-28 12:27:12 UTC

Subject: Bug 26612

Author: jakub
Date: Mon Aug 28 12:26:41 2006
New Revision: 116505

URL: http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=116505
Log:
2006-07-06  Jason Merrill  <jason@redhat.com>

cp/
	PR c++/28279
	* decl2.c (finish_static_data_member_decl): Don't assert
	TREE_PUBLIC.

2006-07-01  Jason Merrill  <jason@redhat.com>

cp/
	PR c++/28215
	* method.c (make_thunk): Unset DECL_USE_TEMPLATE and 
	DECL_TEMPLATE_INFO.

2006-06-30  Jason Merrill  <jason@redhat.com>

objcp/
	* objcp-decl.c (objcp_start_struct): Pass null attributes argument
	to begin_class_definition.

2006-06-29  Jason Merrill  <jason@redhat.com>

	PR c++/26905
	PR c++/26612
	PR c++/27000
	PR c++/26984
	PR c++/19134
	* tree.c (build_decl_stat): Don't hande #pragma visibility here.
	* c-common.c (c_determine_visibility): Handle it here.
	* c-decl.c (finish_decl): Call c_determine_visibility for 
	functions, too.
	* flags.h (enum symbol_visibility): Sort from most to least visibility.
	* tree.h: Likewise.
	* varasm.c (default_assemble_visibility): Likewise.
	* c-common.c (handle_visibility_attribute): Complain about trying
	to give visibility to an already defined class, or trying to change
	declared visibility. Always attach the attribute.

	PR c++/26905
	PR c++/21675
	PR c++/17470
	* attribs.c (decl_attributes): Ignore type-in-place attributes
	once the type has been defined.
cp/
	PR c++/26905
	PR c++/26612
	PR c++/27000
	PR c++/26984
	PR c++/19134
	* decl2.c (determine_visibility): Overhaul.
	(determine_visibility_from_class): Likewise.
	(min_vis_r, type_visibility, constrain_visibility): New fns.
	(constrain_visibility_for_template): Likewise.
	(constrain_class_visibility): Likewise.
	* decl.c (cp_finish_decl): Call determine_visibility for function
	decls, too.
	* name-lookup.c (pushtag): Call determine_visibility.
	* decl.c (duplicate_decls): Don't copy visibility from template to
	specialization.
	* pt.c (check_explicit_specialization): Likewise.
	(lookup_template_class, tsubst_decl): Call determine_visibility.
	* class.c (finish_struct_1): Call constrain_class_visibility.

	PR c++/26905
	PR c++/21675
	PR c++/17470
	* parser.c (cp_parser_explicit_instantiation): Pass the attributes
	to grokdeclarator.
	(cp_parser_type_specifier): Allow 'enum __attribute ((...)) E'.
	(cp_parser_enum_specifier): Likewise.
	(cp_parser_elaborated_type_specifier): Apply attributes if this
	declares only the class.
	(cp_parser_class_specifier): Apply leading attributes immediately.
	* semantics.c (begin_class_definition): Add attributes parameter,
	apply them to the type.

	PR c++/21581
	PR c++/25915
	* tree.c (decl_anon_ns_mem_p): New function.
	* cp-tree.h: Declare it.
	* decl2.c (determine_visibility): Make anonymous namespace
	members static.
	(min_vis_r, constrain_visibility): Likewise.
	* rtti.c (create_pseudo_type_info): Set TREE_PUBLIC on
	pseudo-types.
	* decl.c (cxx_init_decl_processing): Set TREE_PUBLIC on
	global_namespace.
	* name-lookup.c (push_namespace_with_attribs): Don't set TREE_PUBLIC
	on anonymous namespaces.

Added:
    branches/redhat/gcc-4_1-branch/gcc/testsuite/g++.dg/ext/visibility/anon1.C
    branches/redhat/gcc-4_1-branch/gcc/testsuite/g++.dg/ext/visibility/anon2.C
    branches/redhat/gcc-4_1-branch/gcc/testsuite/g++.dg/ext/visibility/class1.C
    branches/redhat/gcc-4_1-branch/gcc/testsuite/g++.dg/ext/visibility/prop1.C
    branches/redhat/gcc-4_1-branch/gcc/testsuite/g++.dg/ext/visibility/redecl1.C
    branches/redhat/gcc-4_1-branch/gcc/testsuite/g++.dg/ext/visibility/template1.C
    branches/redhat/gcc-4_1-branch/gcc/testsuite/g++.dg/ext/visibility/template2.C
    branches/redhat/gcc-4_1-branch/gcc/testsuite/g++.dg/ext/visibility/template3.C
    branches/redhat/gcc-4_1-branch/gcc/testsuite/g++.dg/ext/visibility/template4.C
    branches/redhat/gcc-4_1-branch/gcc/testsuite/g++.dg/ext/visibility/typeinfo1.C
    branches/redhat/gcc-4_1-branch/gcc/testsuite/g++.dg/ext/visibility/warn1.C
    branches/redhat/gcc-4_1-branch/gcc/testsuite/g++.dg/ext/visibility/warn2.C
    branches/redhat/gcc-4_1-branch/gcc/testsuite/g++.dg/ext/visibility/warn3.C
    branches/redhat/gcc-4_1-branch/gcc/testsuite/g++.dg/ext/visibility/warn4.C
    branches/redhat/gcc-4_1-branch/gcc/testsuite/g++.dg/template/anon2.C
Modified:
    branches/redhat/gcc-4_1-branch/gcc/ChangeLog
    branches/redhat/gcc-4_1-branch/gcc/attribs.c
    branches/redhat/gcc-4_1-branch/gcc/c-common.c
    branches/redhat/gcc-4_1-branch/gcc/c-decl.c
    branches/redhat/gcc-4_1-branch/gcc/cp/ChangeLog
    branches/redhat/gcc-4_1-branch/gcc/cp/class.c
    branches/redhat/gcc-4_1-branch/gcc/cp/cp-tree.h
    branches/redhat/gcc-4_1-branch/gcc/cp/decl.c
    branches/redhat/gcc-4_1-branch/gcc/cp/decl2.c
    branches/redhat/gcc-4_1-branch/gcc/cp/method.c
    branches/redhat/gcc-4_1-branch/gcc/cp/name-lookup.c
    branches/redhat/gcc-4_1-branch/gcc/cp/parser.c
    branches/redhat/gcc-4_1-branch/gcc/cp/pt.c
    branches/redhat/gcc-4_1-branch/gcc/cp/rtti.c
    branches/redhat/gcc-4_1-branch/gcc/cp/semantics.c
    branches/redhat/gcc-4_1-branch/gcc/cp/tree.c
    branches/redhat/gcc-4_1-branch/gcc/doc/extend.texi
    branches/redhat/gcc-4_1-branch/gcc/doc/invoke.texi
    branches/redhat/gcc-4_1-branch/gcc/flags.h
    branches/redhat/gcc-4_1-branch/gcc/objcp/ChangeLog
    branches/redhat/gcc-4_1-branch/gcc/objcp/objcp-decl.c
    branches/redhat/gcc-4_1-branch/gcc/testsuite/g++.dg/ext/attrib14.C
    branches/redhat/gcc-4_1-branch/gcc/testsuite/g++.dg/ext/attrib9.C
    branches/redhat/gcc-4_1-branch/gcc/testsuite/g++.dg/ext/visibility/assign1.C
    branches/redhat/gcc-4_1-branch/gcc/testsuite/g++.dg/ext/visibility/fvisibility-override2.C
    branches/redhat/gcc-4_1-branch/gcc/testsuite/g++.dg/ext/visibility/virtual.C
    branches/redhat/gcc-4_1-branch/gcc/testsuite/g++.old-deja/g++.pt/enum5.C
    branches/redhat/gcc-4_1-branch/gcc/tree.c
    branches/redhat/gcc-4_1-branch/gcc/tree.h
    branches/redhat/gcc-4_1-branch/gcc/varasm.c