--- /dev/null
+diff -aur gcc-3.4.0orig/gcc/c-common.c gcc-3.4.0/gcc/c-common.c
+--- gcc-3.4.0orig/gcc/c-common.c 2004-03-19 01:32:59.000000000 +0000
++++ gcc-3.4.0/gcc/c-common.c 2004-05-10 21:05:33.000000000 +0100
+@@ -833,7 +833,7 @@
+ handle_deprecated_attribute },
+ { "vector_size", 1, 1, false, true, false,
+ handle_vector_size_attribute },
+- { "visibility", 1, 1, true, false, false,
++ { "visibility", 1, 1, false, false, false,
+ handle_visibility_attribute },
+ { "tls_model", 1, 1, true, false, false,
+ handle_tls_model_attribute },
+@@ -4886,7 +4886,16 @@
+
+ *no_add_attrs = true;
+
+- if (decl_function_context (decl) != 0 || ! TREE_PUBLIC (decl))
++ if (TYPE_P (*node))
++ {
++ if (TREE_CODE (*node) != RECORD_TYPE && TREE_CODE (*node) != UNION_TYPE)
++ {
++ warning ("`%s' attribute ignored on non-class types",
++ IDENTIFIER_POINTER (name));
++ return NULL_TREE;
++ }
++ }
++ else if (decl_function_context (decl) != 0 || ! TREE_PUBLIC (decl))
+ {
+ warning ("`%s' attribute ignored", IDENTIFIER_POINTER (name));
+ return NULL_TREE;
+@@ -4897,6 +4906,14 @@
+ error ("visibility arg not a string");
+ return NULL_TREE;
+ }
++
++ /* If this is a type, set the visibility on the type decl. */
++ if (TYPE_P (decl))
++ {
++ decl = TYPE_NAME (decl);
++ if (! decl)
++ return NULL_TREE;
++ }
+
+ if (strcmp (TREE_STRING_POINTER (id), "default") == 0)
+ DECL_VISIBILITY (decl) = VISIBILITY_DEFAULT;
+@@ -4908,6 +4925,14 @@
+ DECL_VISIBILITY (decl) = VISIBILITY_PROTECTED;
+ else
+ error ("visibility arg must be one of \"default\", \"hidden\", \"protected\" or \"internal\"");
++ DECL_VISIBILITYSPECIFIED (decl) = 1;
++
++ /* For decls only, go ahead and attach the attribute to the node as well.
++ This is needed so we can determine whether we have VISIBILITY_DEFAULT
++ because the visibility was not specified, or because it was explicitly
++ overridden from the class visibility. */
++ if (DECL_P (*node))
++ *no_add_attrs = false;
+
+ return NULL_TREE;
+ }
+
+diff -aur gcc-3.4.0orig/gcc/c-decl.c gcc-3.4.0/gcc/c-decl.c
+--- gcc-3.4.0orig/gcc/c-decl.c 2004-03-22 17:58:18.000000000 +0000
++++ gcc-3.4.0/gcc/c-decl.c 2004-05-10 15:16:27.000000000 +0100
+@@ -1164,9 +1164,8 @@
+ }
+
+ /* warnings */
+- /* All decls must agree on a non-default visibility. */
+- if (DECL_VISIBILITY (newdecl) != VISIBILITY_DEFAULT
+- && DECL_VISIBILITY (olddecl) != VISIBILITY_DEFAULT
++ /* All decls must agree on a visibility. */
++ if (DECL_VISIBILITYSPECIFIED (newdecl) && DECL_VISIBILITYSPECIFIED (olddecl)
+ && DECL_VISIBILITY (newdecl) != DECL_VISIBILITY (olddecl))
+ {
+ warning ("%Jredeclaration of '%D' with different visibility "
+@@ -1361,9 +1360,12 @@
+ Currently, it can only be defined in the prototype. */
+ COPY_DECL_ASSEMBLER_NAME (olddecl, newdecl);
+
+- /* If either declaration has a nondefault visibility, use it. */
+- if (DECL_VISIBILITY (olddecl) != VISIBILITY_DEFAULT)
+- DECL_VISIBILITY (newdecl) = DECL_VISIBILITY (olddecl);
++ /* Use visibility of whichever declaration had it specified */
++ if (DECL_VISIBILITYSPECIFIED (olddecl))
++ {
++ DECL_VISIBILITY (newdecl) = DECL_VISIBILITY (olddecl);
++ DECL_VISIBILITYSPECIFIED (newdecl) = 1;
++ }
+
+ if (TREE_CODE (newdecl) == FUNCTION_DECL)
+ {
+
+diff -aur gcc-3.4.0orig/gcc/common.opt gcc-3.4.0/gcc/common.opt
+--- gcc-3.4.0orig/gcc/common.opt 2004-02-18 00:09:04.000000000 +0000
++++ gcc-3.4.0/gcc/common.opt 2004-05-09 08:10:50.000000000 +0100
+@@ -718,6 +718,11 @@
+ Common
+ Add extra commentary to assembler output
+
++fvisibility=
++Common Joined RejectNegative
++-fvisibility=[default|internal|hidden|protected] Set the default symbol visibility
++
++
+ fvpt
+ Common
+ Use expression value profiles in optimizations
+
+diff -aur gcc-3.4.0orig/gcc/c.opt gcc-3.4.0/gcc/c.opt
+--- gcc-3.4.0orig/gcc/c.opt 2004-02-18 00:09:03.000000000 +0000
++++ gcc-3.4.0/gcc/c.opt 2004-05-09 08:10:50.000000000 +0100
+@@ -656,6 +656,10 @@
+ C++ ObjC++
+ Use __cxa_atexit to register destructors
+
++fvisibility-inlines-hidden
++C++
++Marks all inlined methods as having hidden visibility
++
+ fvtable-gc
+ C++ ObjC++
+ Discard unused virtual functions
+diff -aur gcc-3.4.0orig/gcc/c-opts.c gcc-3.4.0/gcc/c-opts.c
+--- gcc-3.4.0orig/gcc/c-opts.c 2004-02-18 00:09:03.000000000 +0000
++++ gcc-3.4.0/gcc/c-opts.c 2004-05-09 08:10:50.000000000 +0100
+@@ -912,6 +912,10 @@
+ case OPT_fuse_cxa_atexit:
+ flag_use_cxa_atexit = value;
+ break;
++
++ case OPT_fvisibility_inlines_hidden:
++ visibility_options.inlineshidden = value;
++ break;
+
+ case OPT_fweak:
+ flag_weak = value;
+
+diff -aur gcc-3.4.0orig/gcc/cp/class.c gcc-3.4.0/gcc/cp/class.c
+--- gcc-3.4.0orig/gcc/cp/class.c 2004-03-09 07:27:23.000000000 +0000
++++ gcc-3.4.0/gcc/cp/class.c 2004-05-10 21:06:50.000000000 +0100
+@@ -524,6 +524,10 @@
+ DECL_ALIGN (decl) = MAX (TYPE_ALIGN (double_type_node),
+ DECL_ALIGN (decl));
+
++ /* The vtable's visibility is the class visibility. There is no way
++ to override the visibility for just the vtable. */
++ DECL_VISIBILITY (decl) = CLASSTYPE_VISIBILITY (class_type);
++ DECL_VISIBILITYSPECIFIED (decl) = CLASSTYPE_VISIBILITYSPECIFIED (class_type);
+ import_export_vtable (decl, class_type, 0);
+
+ return decl;
+@@ -2971,7 +2975,25 @@
+ continue;
+
+ if (TREE_CODE (x) == CONST_DECL || TREE_CODE (x) == VAR_DECL)
+- continue;
++ {
++ /* Apply the class's visibility attribute to static members
++ which do not have a visibility attribute. */
++ if (! lookup_attribute ("visibility", DECL_ATTRIBUTES (x)))
++ {
++ if (visibility_options.inlineshidden && DECL_INLINE (x))
++ {
++ DECL_VISIBILITY (x) = VISIBILITY_HIDDEN;
++ DECL_VISIBILITYSPECIFIED (x) = 1;
++ }
++ else
++ {
++ DECL_VISIBILITY (x) = CLASSTYPE_VISIBILITY (current_class_type);
++ DECL_VISIBILITYSPECIFIED (x) = CLASSTYPE_VISIBILITYSPECIFIED (current_class_type);
++ }
++ }
++
++ continue;
++ }
+
+ /* Now it can only be a FIELD_DECL. */
+
+@@ -3708,6 +3730,22 @@
+ check_for_override (x, t);
+ if (DECL_PURE_VIRTUAL_P (x) && ! DECL_VINDEX (x))
+ cp_error_at ("initializer specified for non-virtual method `%D'", x);
++
++ /* Apply the class's visibility attribute to methods which do
++ not have a visibility attribute. */
++ if (! lookup_attribute ("visibility", DECL_ATTRIBUTES (x)))
++ {
++ if (visibility_options.inlineshidden && DECL_INLINE (x))
++ {
++ DECL_VISIBILITY (x) = VISIBILITY_HIDDEN;
++ DECL_VISIBILITYSPECIFIED (x) = 1;
++ }
++ else
++ {
++ DECL_VISIBILITY (x) = CLASSTYPE_VISIBILITY (current_class_type);
++ DECL_VISIBILITYSPECIFIED (x) = CLASSTYPE_VISIBILITYSPECIFIED (current_class_type);
++ }
++ }
+
+ /* The name of the field is the original field name
+ Save this in auxiliary field for later overloading. */
+@@ -7830,3 +7868,4 @@
+ *vid->last_init = build_tree_list (NULL_TREE, init);
+ vid->last_init = &TREE_CHAIN (*vid->last_init);
+ }
++
+
+diff -aur gcc-3.4.0orig/gcc/cp/cp-tree.h gcc-3.4.0/gcc/cp/cp-tree.h
+--- gcc-3.4.0orig/gcc/cp/cp-tree.h 2004-03-20 00:13:08.000000000 +0000
++++ gcc-3.4.0/gcc/cp/cp-tree.h 2004-05-10 20:56:56.000000000 +0100
+@@ -1008,7 +1008,12 @@
+ #define PUBLICLY_UNIQUELY_DERIVED_P(PARENT, TYPE) \
+ (lookup_base ((TYPE), (PARENT), ba_not_special | ba_quiet, NULL) \
+ != NULL_TREE)
+-\f
++
++/* Gives the visibility specification for a class type. */
++#define CLASSTYPE_VISIBILITY(TYPE) DECL_VISIBILITY (TYPE_NAME (TYPE))
++#define CLASSTYPE_VISIBILITYSPECIFIED(TYPE) DECL_VISIBILITYSPECIFIED (TYPE_NAME (TYPE))
++
++
+ /* This is a few header flags for 'struct lang_type'. Actually,
+ all but the first are used only for lang_type_class; they
+ are put in this structure to save space. */
+
+diff -aur gcc-3.4.0orig/gcc/cp/decl.c gcc-3.4.0/gcc/cp/decl.c
+--- gcc-3.4.0orig/gcc/cp/decl.c 2004-04-01 21:47:21.000000000 +0100
++++ gcc-3.4.0/gcc/cp/decl.c 2004-05-28 21:16:11.000000000 +0100
+@@ -1869,17 +1869,34 @@
+ DECL_COMMON (newdecl) = DECL_COMMON (olddecl);
+ COPY_DECL_ASSEMBLER_NAME (olddecl, newdecl);
+
+- /* If either declaration has a nondefault visibility, use it. */
+- if (DECL_VISIBILITY (olddecl) != VISIBILITY_DEFAULT)
++ /* Warn about conflicting visibility specifications. */
++ if (DECL_VISIBILITYSPECIFIED (olddecl) && DECL_VISIBILITYSPECIFIED (newdecl)
++ && DECL_VISIBILITY (newdecl) != DECL_VISIBILITY (olddecl))
++ {
++ warning ("%J'%D': visibility attribute ignored because it",
++ newdecl, newdecl);
++ warning ("%Jconflicts with previous declaration here", olddecl);
++ }
++ /* Choose the declaration which specified visibility. */
++ if (DECL_VISIBILITYSPECIFIED (olddecl))
+ {
+- if (DECL_VISIBILITY (newdecl) != VISIBILITY_DEFAULT
+- && DECL_VISIBILITY (newdecl) != DECL_VISIBILITY (olddecl))
+- {
+- warning ("%J'%D': visibility attribute ignored because it",
+- newdecl, newdecl);
+- warning ("%Jconflicts with previous declaration here", olddecl);
+- }
+ DECL_VISIBILITY (newdecl) = DECL_VISIBILITY (olddecl);
++ DECL_VISIBILITYSPECIFIED (newdecl) = 1;
++ }
++ /* If it's a definition of a global operator new or operator
++ delete, it must be default visibility. */
++ if (NEW_DELETE_OPNAME_P (DECL_NAME (newdecl)) && DECL_INITIAL (newdecl) != NULL_TREE)
++ {
++ if (!DECL_FUNCTION_MEMBER_P (newdecl) && VISIBILITY_DEFAULT != DECL_VISIBILITY (newdecl))
++ {
++ warning ("%J`%D': ignoring non-default symbol",
++ newdecl, newdecl);
++ warning ("%Jvisibility on global operator new or delete", newdecl);
++ DECL_VISIBILITY (olddecl) = VISIBILITY_DEFAULT;
++ DECL_VISIBILITYSPECIFIED (olddecl) = 1;
++ DECL_VISIBILITY (newdecl) = VISIBILITY_DEFAULT;
++ DECL_VISIBILITYSPECIFIED (newdecl) = 1;
++ }
+ }
+
+ if (TREE_CODE (newdecl) == FUNCTION_DECL)
+
+diff -aur gcc-3.4.0orig/gcc/cp/method.c gcc-3.4.0/gcc/cp/method.c
+--- gcc-3.4.0orig/gcc/cp/method.c 2004-04-08 23:15:58.000000000 +0100
++++ gcc-3.4.0/gcc/cp/method.c 2004-05-09 08:10:52.000000000 +0100
+@@ -394,6 +394,7 @@
+ rewrite. */
+ TREE_PUBLIC (thunk_fndecl) = TREE_PUBLIC (function);
+ DECL_VISIBILITY (thunk_fndecl) = DECL_VISIBILITY (function);
++ DECL_VISIBILITYSPECIFIED (thunk_fndecl) = DECL_VISIBILITYSPECIFIED (function);
+
+ if (flag_syntax_only)
+ {
+
+diff -aur gcc-3.4.0orig/gcc/cp/optimize.c gcc-3.4.0/gcc/cp/optimize.c
+--- gcc-3.4.0orig/gcc/cp/optimize.c 2004-02-08 01:52:50.000000000 +0000
++++ gcc-3.4.0/gcc/cp/optimize.c 2004-05-09 08:10:52.000000000 +0100
+@@ -155,6 +155,7 @@
+ DECL_NOT_REALLY_EXTERN (clone) = DECL_NOT_REALLY_EXTERN (fn);
+ TREE_PUBLIC (clone) = TREE_PUBLIC (fn);
+ DECL_VISIBILITY (clone) = DECL_VISIBILITY (fn);
++ DECL_VISIBILITYSPECIFIED (clone) = DECL_VISIBILITYSPECIFIED (fn);
+
+ /* Adjust the parameter names and locations. */
+ parm = DECL_ARGUMENTS (fn);
+
+diff -aur gcc-3.4.0orig/gcc/cp/rtti.c gcc-3.4.0/gcc/cp/rtti.c
+--- gcc-3.4.0orig/gcc/cp/rtti.c 2004-03-08 23:00:26.000000000 +0000
++++ gcc-3.4.0/gcc/cp/rtti.c 2004-05-10 21:09:21.000000000 +0100
+@@ -361,7 +361,11 @@
+ pushdecl_top_level_and_finish (d, NULL_TREE);
+
+ if (CLASS_TYPE_P (type))
+- CLASSTYPE_TYPEINFO_VAR (TYPE_MAIN_VARIANT (type)) = d;
++ {
++ CLASSTYPE_TYPEINFO_VAR (TYPE_MAIN_VARIANT (type)) = d;
++ DECL_VISIBILITY (d) = CLASSTYPE_VISIBILITY (type);
++ DECL_VISIBILITYSPECIFIED (d) = CLASSTYPE_VISIBILITYSPECIFIED (type);
++ }
+
+ /* Remember the type it is for. */
+ TREE_TYPE (name) = type;
+@@ -759,6 +763,11 @@
+ TREE_STATIC (name_decl) = 1;
+ DECL_EXTERNAL (name_decl) = 0;
+ TREE_PUBLIC (name_decl) = 1;
++ if (CLASS_TYPE_P (target))
++ {
++ DECL_VISIBILITY (name_decl) = CLASSTYPE_VISIBILITY (target);
++ DECL_VISIBILITYSPECIFIED (name_decl) = CLASSTYPE_VISIBILITYSPECIFIED (target);
++ }
+ import_export_tinfo (name_decl, target, typeinfo_in_lib_p (target));
+ /* External name of the string containing the type's name has a
+ special name. */
+
+diff -aur gcc-3.4.0orig/gcc/c-pragma.c gcc-3.4.0/gcc/c-pragma.c
+--- gcc-3.4.0orig/gcc/c-pragma.c 2004-01-23 23:35:53.000000000 +0000
++++ gcc-3.4.0/gcc/c-pragma.c 2004-05-09 08:10:52.000000000 +0100
+@@ -480,6 +480,86 @@
+ return asmname;
+ }
+
++
++#ifdef HANDLE_PRAGMA_VISIBILITY
++static void handle_pragma_visibility (cpp_reader *);
++
++/* Sets the default visibility for symbols to something other than that
++ specified on the command line. */
++static void
++handle_pragma_visibility (cpp_reader *dummy ATTRIBUTE_UNUSED)
++{ /* Form is #pragma GCC visibility push(hidden)|pop */
++ static int visstack [16], visidx;
++ tree x;
++ enum cpp_ttype token;
++ enum { bad, push, pop } action = bad;
++
++ token = c_lex (&x);
++ if (token == CPP_NAME)
++ {
++ const char *op = IDENTIFIER_POINTER (x);
++ if (!strcmp (op, "push"))
++ action = push;
++ else if (!strcmp (op, "pop"))
++ action = pop;
++ }
++ if (bad == action)
++ GCC_BAD ("#pragma GCC visibility must be followed by push or pop");
++ else
++ {
++ if (pop == action)
++ {
++ if (!visidx)
++ {
++ GCC_BAD ("No matching push for '#pragma GCC visibility pop'");
++ }
++ else
++ {
++ default_visibility = visstack[--visidx];
++ visibility_options.inpragma = (visidx>0);
++ }
++ }
++ else
++ {
++ if (c_lex (&x) != CPP_OPEN_PAREN)
++ GCC_BAD ("missing '(' after '#pragma GCC visibility push' - ignored");
++ token = c_lex (&x);
++ if (token != CPP_NAME)
++ {
++ GCC_BAD ("malformed #pragma GCC visibility push");
++ }
++ else if (visidx >= 16)
++ {
++ GCC_BAD ("No more than sixteen #pragma GCC visibility pushes allowed at once");
++ }
++ else
++ {
++ const char *str = IDENTIFIER_POINTER (x);
++ visstack[visidx++] = default_visibility;
++ if (!strcmp (str, "default"))
++ default_visibility = VISIBILITY_DEFAULT;
++ else if (!strcmp (str, "internal"))
++ default_visibility = VISIBILITY_INTERNAL;
++ else if (!strcmp (str, "hidden"))
++ default_visibility = VISIBILITY_HIDDEN;
++ else if (!strcmp (str, "protected"))
++ default_visibility = VISIBILITY_PROTECTED;
++ else
++ {
++ GCC_BAD ("#pragma GCC visibility push() must specify default, internal, hidden or protected");
++ }
++ visibility_options.inpragma = 1;
++ }
++ if (c_lex (&x) != CPP_CLOSE_PAREN)
++ GCC_BAD ("missing '(' after '#pragma GCC visibility push' - ignored");
++ }
++ }
++ if (c_lex (&x) != CPP_EOF)
++ warning ("junk at end of '#pragma GCC visibility'");
++}
++
++#endif
++
+ /* Front-end wrapper for pragma registration to avoid dragging
+ cpplib.h in almost everywhere. */
+ void
+@@ -505,6 +585,9 @@
+ #ifdef HANDLE_PRAGMA_EXTERN_PREFIX
+ c_register_pragma (0, "extern_prefix", handle_pragma_extern_prefix);
+ #endif
++#ifdef HANDLE_PRAGMA_VISIBILITY
++ c_register_pragma ("GCC", "visibility", handle_pragma_visibility);
++#endif
+
+ #ifdef REGISTER_TARGET_PRAGMAS
+ REGISTER_TARGET_PRAGMAS ();
+diff -aur gcc-3.4.0orig/gcc/c-pragma.h gcc-3.4.0/gcc/c-pragma.h
+--- gcc-3.4.0orig/gcc/c-pragma.h 2004-01-31 06:18:05.000000000 +0000
++++ gcc-3.4.0/gcc/c-pragma.h 2004-05-09 08:10:53.000000000 +0100
+@@ -44,6 +44,11 @@
+ #define HANDLE_PRAGMA_PACK 1
+ #endif /* HANDLE_PRAGMA_PACK_PUSH_POP */
+
++/* It's safe to always leave visibility pragma enabled as if
++ visibility is not supported on the host OS platform the
++ statements are ignored. */
++#define HANDLE_PRAGMA_VISIBILITY 1
++
+ extern void init_pragma (void);
+
+ /* Front-end wrapper for pragma registration to avoid dragging
+
+
+diff -aur gcc-3.4.0orig/gcc/doc/invoke.texi gcc-3.4.0/gcc/doc/invoke.texi
+--- gcc-3.4.0orig/gcc/doc/invoke.texi 2004-04-19 00:05:36.000000000 +0100
++++ gcc-3.4.0/gcc/doc/invoke.texi 2004-05-28 21:29:36.000000000 +0100
+@@ -183,7 +183,8 @@
+ -fno-optional-diags -fpermissive @gol
+ -frepo -fno-rtti -fstats -ftemplate-depth-@var{n} @gol
+ -fuse-cxa-atexit -fno-weak -nostdinc++ @gol
+--fno-default-inline -Wabi -Wctor-dtor-privacy @gol
++-fno-default-inline -fvisibility-inlines-hidden @gol
++-Wabi -Wctor-dtor-privacy @gol
+ -Wnon-virtual-dtor -Wreorder @gol
+ -Weffc++ -Wno-deprecated @gol
+ -Wno-non-template-friend -Wold-style-cast @gol
+@@ -674,7 +675,8 @@
+ -fargument-alias -fargument-noalias @gol
+ -fargument-noalias-global -fleading-underscore @gol
+ -ftls-model=@var{model} @gol
+--ftrapv -fwrapv -fbounds-check}
++-ftrapv -fwrapv -fbounds-check @gol
++-fvisibility}
+ @end table
+
+ @menu
+@@ -1433,6 +1435,20 @@
+ destructors, but will only work if your C library supports
+ @code{__cxa_atexit}.
+
++@item -fvisibility-inlines-hidden
++@opindex fvisibility-inlines-hidden
++Causes all inlined methods to be marked with
++@code{__attribute__ ((visibility ("hidden")))} so that they do not
++appear in the export table of a DSO and do not require a PLT indirection
++when used within the DSO. Enabling this option can have a dramatic effect
++on load and link times of a DSO as it massively reduces the size of the
++dynamic export table when the library makes heavy use of templates. While
++it can cause bloating through duplication of code within each DSO where
++it is used, often the wastage is less than the considerable space occupied
++by a long symbol name in the export table which is typical when using
++templates and namespaces. For even more savings, combine with the
++@code{-fvisibility=hidden} switch.
++
+ @item -fno-weak
+ @opindex fno-weak
+ Do not use weak symbol support, even if it is provided by the linker.
+@@ -11198,6 +11214,54 @@
+
+ The default without @option{-fpic} is @code{initial-exec}; with
+ @option{-fpic} the default is @code{global-dynamic}.
++
++@item -fvisibility=@var{default|internal|hidden|protected}
++@opindex fvisibility
++Set the default ELF image symbol visibility to the specified option - all
++symbols will be marked with this unless overrided within the code.
++Using this feature can very substantially improve linking and
++load times of shared object libraries, produce more optimised
++code, provide near-perfect API export and prevent symbol clashes.
++It is @strong{strongly} recommended that you use this in any shared objects
++you distribute.
++
++Despite the nomenclature, @code{default} always means public ie;
++available to be linked against from outside the shared object.
++@code{protected} and @code{internal} are pretty useless in real-world
++usage so the only other commonly used option will be @code{hidden}.
++The default if -fvisibility isn't specified is @code{default} ie; make every
++symbol public - this causes the same behaviour as previous versions of
++GCC.
++
++A good explanation of the benefits offered by ensuring ELF
++symbols have the correct visibility is given by ``How To Write
++Shared Libraries'' by Ulrich Drepper (which can be found at
++@w{@uref{http://people.redhat.com/~drepper/}}) - however a superior
++solution made possible by this option to marking things hidden when
++the default is public is to make the default hidden and mark things
++public. This is the norm with DLL's on Windows and with @option{-fvisibility=hidden}
++and @code{__attribute__ ((visibility("default")))} instead of
++@code{__declspec(dllexport)} you get almost identical semantics with
++identical syntax. This is a great boon to those working with
++cross-platform projects.
++
++For those adding visibility support to existing code, you may find
++@samp{#pragma GCC visibility} of use. This works by you enclosing
++the declarations you wish to set visibility for with (for example)
++@samp{#pragma GCC visibility push(hidden)} and
++@samp{#pragma GCC visibility pop}. These can be nested up to sixteen
++times. Bear in mind that symbol visibility should be viewed @strong{as
++part of the API interface contract} and thus all new code should
++always specify visibility when it is not the default ie; declarations
++only for use within the local DSO should @strong{always} be marked explicitly
++as hidden as so to avoid PLT indirection overheads - making this
++abundantly clear also aids readability and self-documentation of the code.
++Note that due to ISO C++ specification requirements, operator new and
++operator delete must always be of default visibility.
++
++An overview of these techniques, their benefits and how to use them
++is at @w{@uref{http://www.nedprod.com/programs/gccvisibility.html}}.
++
+ @end table
+
+ @c man end
+
+diff -aur gcc-3.4.0orig/gcc/flags.h gcc-3.4.0/gcc/flags.h
+--- gcc-3.4.0orig/gcc/flags.h 2004-02-18 00:09:04.000000000 +0000
++++ gcc-3.4.0/gcc/flags.h 2004-05-09 08:10:53.000000000 +0100
+@@ -60,6 +60,30 @@
+ /* Nonzero means emit debugging information only for symbols which are used. */
+ extern int flag_debug_only_used_symbols;
+
++/* Enumerate visibility settings. */
++#ifndef SYMBOL_VISIBILITY_DEFINED
++#define SYMBOL_VISIBILITY_DEFINED
++enum symbol_visibility
++{
++ VISIBILITY_DEFAULT,
++ VISIBILITY_INTERNAL,
++ VISIBILITY_HIDDEN,
++ VISIBILITY_PROTECTED
++};
++#endif
++
++/* The default visibility for all symbols (unless overridden). */
++extern enum symbol_visibility default_visibility;
++
++struct visibility_flags
++{
++ unsigned inpragma : 1; /* True when in #pragma GCC visibility. */
++ unsigned inlineshidden : 1; /* True when -finlineshidden in effect. */
++};
++
++/* Global visibility options. */
++extern struct visibility_flags visibility_options;
++
+ /* Nonzero means do optimizations. -opt. */
+
+ extern int optimize;
+
+diff -aur gcc-3.4.0orig/gcc/opts.c gcc-3.4.0/gcc/opts.c
+--- gcc-3.4.0orig/gcc/opts.c 2004-02-18 00:09:04.000000000 +0000
++++ gcc-3.4.0/gcc/opts.c 2004-05-09 08:10:53.000000000 +0100
+@@ -142,6 +142,12 @@
+ write_symbols is set to DBX_DEBUG, XCOFF_DEBUG, or DWARF_DEBUG. */
+ bool use_gnu_debug_info_extensions;
+
++/* The default visibility for all symbols (unless overridden) */
++enum symbol_visibility default_visibility = VISIBILITY_DEFAULT;
++
++/* Global visibility options. */
++struct visibility_flags visibility_options;
++
+ /* Columns of --help display. */
+ static unsigned int columns = 80;
+
+@@ -1440,6 +1446,21 @@
+ flag_verbose_asm = value;
+ break;
+
++ case OPT_fvisibility_:
++ {
++ if(!strcmp(arg, "default"))
++ default_visibility=VISIBILITY_DEFAULT;
++ else if(!strcmp(arg, "internal"))
++ default_visibility=VISIBILITY_INTERNAL;
++ else if(!strcmp(arg, "hidden"))
++ default_visibility=VISIBILITY_HIDDEN;
++ else if(!strcmp(arg, "protected"))
++ default_visibility=VISIBILITY_PROTECTED;
++ else
++ error("unrecognised visibility value \"%s\"", arg);
++ }
++ break;
++
+ case OPT_fweb:
+ flag_web = value;
+ break;
+
+diff -aur gcc-3.4.0orig/gcc/tree.c gcc-3.4.0/gcc/tree.c
+--- gcc-3.4.0orig/gcc/tree.c 2004-02-05 22:01:35.000000000 +0000
++++ gcc-3.4.0/gcc/tree.c 2004-05-10 15:22:52.000000000 +0100
+@@ -2563,6 +2563,11 @@
+ layout_decl (t, 0);
+ else if (code == FUNCTION_DECL)
+ DECL_MODE (t) = FUNCTION_MODE;
++
++ /* Set default visibility to whatever the user supplied with
++ visibility_specified depending on #pragma GCC visibility. */
++ DECL_VISIBILITY (t) = default_visibility;
++ DECL_VISIBILITYSPECIFIED (t) = visibility_options.inpragma;
+
+ return t;
+ }
+
+diff -aur gcc-3.4.0orig/gcc/tree.h gcc-3.4.0/gcc/tree.h
+--- gcc-3.4.0orig/gcc/tree.h 2004-02-08 01:52:43.000000000 +0000
++++ gcc-3.4.0/gcc/tree.h 2004-05-09 08:10:54.000000000 +0100
+@@ -1499,6 +1499,10 @@
+ /* Value of the decls's visibility attribute */
+ #define DECL_VISIBILITY(NODE) (DECL_CHECK (NODE)->decl.visibility)
+
++/* Nonzero means that the decl had its visibility specified rather than
++ being inferred. */
++#define DECL_VISIBILITYSPECIFIED(NODE) (DECL_CHECK (NODE)->decl.visibility_specified)
++
+ /* In a FUNCTION_DECL, nonzero if the function cannot be inlined. */
+ #define DECL_UNINLINABLE(NODE) (FUNCTION_DECL_CHECK (NODE)->decl.uninlinable)
+
+@@ -1633,7 +1637,8 @@
+ || TREE_CODE (DECL_CONTEXT (EXP)) == TRANSLATION_UNIT_DECL)
+
+ /* Enumerate visibility settings. */
+-
++#ifndef SYMBOL_VISIBILITY_DEFINED
++#define SYMBOL_VISIBILITY_DEFINED
+ enum symbol_visibility
+ {
+ VISIBILITY_DEFAULT,
+@@ -1641,6 +1646,7 @@
+ VISIBILITY_HIDDEN,
+ VISIBILITY_PROTECTED
+ };
++#endif
+
+ struct function;
+
+@@ -1684,8 +1690,7 @@
+ unsigned thread_local_flag : 1;
+ unsigned declared_inline_flag : 1;
+ ENUM_BITFIELD(symbol_visibility) visibility : 2;
+- unsigned unused : 1;
+- /* one unused bit. */
++ unsigned visibility_specified : 1;
+
+ unsigned lang_flag_0 : 1;
+ unsigned lang_flag_1 : 1;
+
+diff -aur gcc-3.4.0orig/gcc/varasm.c gcc-3.4.0/gcc/varasm.c
+--- gcc-3.4.0orig/gcc/varasm.c 2004-04-14 22:14:08.000000000 +0100
++++ gcc-3.4.0/gcc/varasm.c 2004-05-09 08:10:54.000000000 +0100
+@@ -5150,8 +5150,8 @@
+ /* Static variables are always local. */
+ else if (! TREE_PUBLIC (exp))
+ local_p = true;
+- /* A variable is local if the user tells us so. */
+- else if (DECL_VISIBILITY (exp) != VISIBILITY_DEFAULT)
++ /* A variable is local if the user explicitly tells us so. */
++ else if (DECL_VISIBILITYSPECIFIED (exp) && DECL_VISIBILITY (exp) != VISIBILITY_DEFAULT)
+ local_p = true;
+ /* Otherwise, variables defined outside this object may not be local. */
+ else if (DECL_EXTERNAL (exp))
+@@ -5159,6 +5159,9 @@
+ /* Linkonce and weak data are never local. */
+ else if (DECL_ONE_ONLY (exp) || DECL_WEAK (exp))
+ local_p = false;
++ /* If none of the above and visibility is not default, make local. */
++ else if (DECL_VISIBILITY (exp) != VISIBILITY_DEFAULT)
++ local_p = true;
+ /* If PIC, then assume that any global name can be overridden by
+ symbols resolved from other modules. */
+ else if (shlib)
+
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