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[packages/gcc3.4.git] / gcc3.4-visibility.patch
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8a43a6d0 1diff -aur gcc-3.4.0orig/gcc/c-common.c gcc-3.4.0/gcc/c-common.c
2--- gcc-3.4.0orig/gcc/c-common.c 2004-03-19 01:32:59.000000000 +0000
3+++ gcc-3.4.0/gcc/c-common.c 2004-05-10 21:05:33.000000000 +0100
4@@ -833,7 +833,7 @@
5 handle_deprecated_attribute },
6 { "vector_size", 1, 1, false, true, false,
7 handle_vector_size_attribute },
8- { "visibility", 1, 1, true, false, false,
9+ { "visibility", 1, 1, false, false, false,
10 handle_visibility_attribute },
11 { "tls_model", 1, 1, true, false, false,
12 handle_tls_model_attribute },
13@@ -4886,7 +4886,16 @@
14
15 *no_add_attrs = true;
16
17- if (decl_function_context (decl) != 0 || ! TREE_PUBLIC (decl))
18+ if (TYPE_P (*node))
19+ {
20+ if (TREE_CODE (*node) != RECORD_TYPE && TREE_CODE (*node) != UNION_TYPE)
21+ {
22+ warning ("`%s' attribute ignored on non-class types",
23+ IDENTIFIER_POINTER (name));
24+ return NULL_TREE;
25+ }
26+ }
27+ else if (decl_function_context (decl) != 0 || ! TREE_PUBLIC (decl))
28 {
29 warning ("`%s' attribute ignored", IDENTIFIER_POINTER (name));
30 return NULL_TREE;
31@@ -4897,6 +4906,14 @@
32 error ("visibility arg not a string");
33 return NULL_TREE;
34 }
35+
36+ /* If this is a type, set the visibility on the type decl. */
37+ if (TYPE_P (decl))
38+ {
39+ decl = TYPE_NAME (decl);
40+ if (! decl)
41+ return NULL_TREE;
42+ }
43
44 if (strcmp (TREE_STRING_POINTER (id), "default") == 0)
45 DECL_VISIBILITY (decl) = VISIBILITY_DEFAULT;
46@@ -4908,6 +4925,14 @@
47 DECL_VISIBILITY (decl) = VISIBILITY_PROTECTED;
48 else
49 error ("visibility arg must be one of \"default\", \"hidden\", \"protected\" or \"internal\"");
50+ DECL_VISIBILITYSPECIFIED (decl) = 1;
51+
52+ /* For decls only, go ahead and attach the attribute to the node as well.
53+ This is needed so we can determine whether we have VISIBILITY_DEFAULT
54+ because the visibility was not specified, or because it was explicitly
55+ overridden from the class visibility. */
56+ if (DECL_P (*node))
57+ *no_add_attrs = false;
58
59 return NULL_TREE;
60 }
61
62diff -aur gcc-3.4.0orig/gcc/c-decl.c gcc-3.4.0/gcc/c-decl.c
63--- gcc-3.4.0orig/gcc/c-decl.c 2004-03-22 17:58:18.000000000 +0000
64+++ gcc-3.4.0/gcc/c-decl.c 2004-05-10 15:16:27.000000000 +0100
65@@ -1164,9 +1164,8 @@
66 }
67
68 /* warnings */
69- /* All decls must agree on a non-default visibility. */
70- if (DECL_VISIBILITY (newdecl) != VISIBILITY_DEFAULT
71- && DECL_VISIBILITY (olddecl) != VISIBILITY_DEFAULT
72+ /* All decls must agree on a visibility. */
73+ if (DECL_VISIBILITYSPECIFIED (newdecl) && DECL_VISIBILITYSPECIFIED (olddecl)
74 && DECL_VISIBILITY (newdecl) != DECL_VISIBILITY (olddecl))
75 {
76 warning ("%Jredeclaration of '%D' with different visibility "
77@@ -1361,9 +1360,12 @@
78 Currently, it can only be defined in the prototype. */
79 COPY_DECL_ASSEMBLER_NAME (olddecl, newdecl);
80
81- /* If either declaration has a nondefault visibility, use it. */
82- if (DECL_VISIBILITY (olddecl) != VISIBILITY_DEFAULT)
83- DECL_VISIBILITY (newdecl) = DECL_VISIBILITY (olddecl);
84+ /* Use visibility of whichever declaration had it specified */
85+ if (DECL_VISIBILITYSPECIFIED (olddecl))
86+ {
87+ DECL_VISIBILITY (newdecl) = DECL_VISIBILITY (olddecl);
88+ DECL_VISIBILITYSPECIFIED (newdecl) = 1;
89+ }
90
91 if (TREE_CODE (newdecl) == FUNCTION_DECL)
92 {
93
94diff -aur gcc-3.4.0orig/gcc/common.opt gcc-3.4.0/gcc/common.opt
95--- gcc-3.4.0orig/gcc/common.opt 2004-02-18 00:09:04.000000000 +0000
96+++ gcc-3.4.0/gcc/common.opt 2004-05-09 08:10:50.000000000 +0100
97@@ -718,6 +718,11 @@
98 Common
99 Add extra commentary to assembler output
100
101+fvisibility=
102+Common Joined RejectNegative
103+-fvisibility=[default|internal|hidden|protected] Set the default symbol visibility
104+
105+
106 fvpt
107 Common
108 Use expression value profiles in optimizations
109
110diff -aur gcc-3.4.0orig/gcc/c.opt gcc-3.4.0/gcc/c.opt
111--- gcc-3.4.0orig/gcc/c.opt 2004-02-18 00:09:03.000000000 +0000
112+++ gcc-3.4.0/gcc/c.opt 2004-05-09 08:10:50.000000000 +0100
113@@ -656,6 +656,10 @@
114 C++ ObjC++
115 Use __cxa_atexit to register destructors
116
117+fvisibility-inlines-hidden
118+C++
119+Marks all inlined methods as having hidden visibility
120+
121 fvtable-gc
122 C++ ObjC++
123 Discard unused virtual functions
124diff -aur gcc-3.4.0orig/gcc/c-opts.c gcc-3.4.0/gcc/c-opts.c
125--- gcc-3.4.0orig/gcc/c-opts.c 2004-02-18 00:09:03.000000000 +0000
126+++ gcc-3.4.0/gcc/c-opts.c 2004-05-09 08:10:50.000000000 +0100
127@@ -912,6 +912,10 @@
128 case OPT_fuse_cxa_atexit:
129 flag_use_cxa_atexit = value;
130 break;
131+
132+ case OPT_fvisibility_inlines_hidden:
133+ visibility_options.inlineshidden = value;
134+ break;
135
136 case OPT_fweak:
137 flag_weak = value;
138
139diff -aur gcc-3.4.0orig/gcc/cp/class.c gcc-3.4.0/gcc/cp/class.c
140--- gcc-3.4.0orig/gcc/cp/class.c 2004-03-09 07:27:23.000000000 +0000
141+++ gcc-3.4.0/gcc/cp/class.c 2004-05-10 21:06:50.000000000 +0100
142@@ -524,6 +524,10 @@
143 DECL_ALIGN (decl) = MAX (TYPE_ALIGN (double_type_node),
144 DECL_ALIGN (decl));
145
146+ /* The vtable's visibility is the class visibility. There is no way
147+ to override the visibility for just the vtable. */
148+ DECL_VISIBILITY (decl) = CLASSTYPE_VISIBILITY (class_type);
149+ DECL_VISIBILITYSPECIFIED (decl) = CLASSTYPE_VISIBILITYSPECIFIED (class_type);
150 import_export_vtable (decl, class_type, 0);
151
152 return decl;
153@@ -2971,7 +2975,25 @@
154 continue;
155
156 if (TREE_CODE (x) == CONST_DECL || TREE_CODE (x) == VAR_DECL)
157- continue;
158+ {
159+ /* Apply the class's visibility attribute to static members
160+ which do not have a visibility attribute. */
161+ if (! lookup_attribute ("visibility", DECL_ATTRIBUTES (x)))
162+ {
163+ if (visibility_options.inlineshidden && DECL_INLINE (x))
164+ {
165+ DECL_VISIBILITY (x) = VISIBILITY_HIDDEN;
166+ DECL_VISIBILITYSPECIFIED (x) = 1;
167+ }
168+ else
169+ {
170+ DECL_VISIBILITY (x) = CLASSTYPE_VISIBILITY (current_class_type);
171+ DECL_VISIBILITYSPECIFIED (x) = CLASSTYPE_VISIBILITYSPECIFIED (current_class_type);
172+ }
173+ }
174+
175+ continue;
176+ }
177
178 /* Now it can only be a FIELD_DECL. */
179
180@@ -3708,6 +3730,22 @@
181 check_for_override (x, t);
182 if (DECL_PURE_VIRTUAL_P (x) && ! DECL_VINDEX (x))
183 cp_error_at ("initializer specified for non-virtual method `%D'", x);
184+
185+ /* Apply the class's visibility attribute to methods which do
186+ not have a visibility attribute. */
187+ if (! lookup_attribute ("visibility", DECL_ATTRIBUTES (x)))
188+ {
189+ if (visibility_options.inlineshidden && DECL_INLINE (x))
190+ {
191+ DECL_VISIBILITY (x) = VISIBILITY_HIDDEN;
192+ DECL_VISIBILITYSPECIFIED (x) = 1;
193+ }
194+ else
195+ {
196+ DECL_VISIBILITY (x) = CLASSTYPE_VISIBILITY (current_class_type);
197+ DECL_VISIBILITYSPECIFIED (x) = CLASSTYPE_VISIBILITYSPECIFIED (current_class_type);
198+ }
199+ }
200
201 /* The name of the field is the original field name
202 Save this in auxiliary field for later overloading. */
203@@ -7830,3 +7868,4 @@
204 *vid->last_init = build_tree_list (NULL_TREE, init);
205 vid->last_init = &TREE_CHAIN (*vid->last_init);
206 }
207+
208
209diff -aur gcc-3.4.0orig/gcc/cp/cp-tree.h gcc-3.4.0/gcc/cp/cp-tree.h
210--- gcc-3.4.0orig/gcc/cp/cp-tree.h 2004-03-20 00:13:08.000000000 +0000
211+++ gcc-3.4.0/gcc/cp/cp-tree.h 2004-05-10 20:56:56.000000000 +0100
212@@ -1008,7 +1008,12 @@
213 #define PUBLICLY_UNIQUELY_DERIVED_P(PARENT, TYPE) \
214 (lookup_base ((TYPE), (PARENT), ba_not_special | ba_quiet, NULL) \
215 != NULL_TREE)
216-\f
217+
218+/* Gives the visibility specification for a class type. */
219+#define CLASSTYPE_VISIBILITY(TYPE) DECL_VISIBILITY (TYPE_NAME (TYPE))
220+#define CLASSTYPE_VISIBILITYSPECIFIED(TYPE) DECL_VISIBILITYSPECIFIED (TYPE_NAME (TYPE))
221+
222+
223 /* This is a few header flags for 'struct lang_type'. Actually,
224 all but the first are used only for lang_type_class; they
225 are put in this structure to save space. */
226
227diff -aur gcc-3.4.0orig/gcc/cp/decl.c gcc-3.4.0/gcc/cp/decl.c
228--- gcc-3.4.0orig/gcc/cp/decl.c 2004-04-01 21:47:21.000000000 +0100
229+++ gcc-3.4.0/gcc/cp/decl.c 2004-05-28 21:16:11.000000000 +0100
230@@ -1869,17 +1869,34 @@
231 DECL_COMMON (newdecl) = DECL_COMMON (olddecl);
232 COPY_DECL_ASSEMBLER_NAME (olddecl, newdecl);
233
234- /* If either declaration has a nondefault visibility, use it. */
235- if (DECL_VISIBILITY (olddecl) != VISIBILITY_DEFAULT)
236+ /* Warn about conflicting visibility specifications. */
237+ if (DECL_VISIBILITYSPECIFIED (olddecl) && DECL_VISIBILITYSPECIFIED (newdecl)
238+ && DECL_VISIBILITY (newdecl) != DECL_VISIBILITY (olddecl))
239+ {
240+ warning ("%J'%D': visibility attribute ignored because it",
241+ newdecl, newdecl);
242+ warning ("%Jconflicts with previous declaration here", olddecl);
243+ }
244+ /* Choose the declaration which specified visibility. */
245+ if (DECL_VISIBILITYSPECIFIED (olddecl))
246 {
247- if (DECL_VISIBILITY (newdecl) != VISIBILITY_DEFAULT
248- && DECL_VISIBILITY (newdecl) != DECL_VISIBILITY (olddecl))
249- {
250- warning ("%J'%D': visibility attribute ignored because it",
251- newdecl, newdecl);
252- warning ("%Jconflicts with previous declaration here", olddecl);
253- }
254 DECL_VISIBILITY (newdecl) = DECL_VISIBILITY (olddecl);
255+ DECL_VISIBILITYSPECIFIED (newdecl) = 1;
256+ }
257+ /* If it's a definition of a global operator new or operator
258+ delete, it must be default visibility. */
259+ if (NEW_DELETE_OPNAME_P (DECL_NAME (newdecl)) && DECL_INITIAL (newdecl) != NULL_TREE)
260+ {
261+ if (!DECL_FUNCTION_MEMBER_P (newdecl) && VISIBILITY_DEFAULT != DECL_VISIBILITY (newdecl))
262+ {
263+ warning ("%J`%D': ignoring non-default symbol",
264+ newdecl, newdecl);
265+ warning ("%Jvisibility on global operator new or delete", newdecl);
266+ DECL_VISIBILITY (olddecl) = VISIBILITY_DEFAULT;
267+ DECL_VISIBILITYSPECIFIED (olddecl) = 1;
268+ DECL_VISIBILITY (newdecl) = VISIBILITY_DEFAULT;
269+ DECL_VISIBILITYSPECIFIED (newdecl) = 1;
270+ }
271 }
272
273 if (TREE_CODE (newdecl) == FUNCTION_DECL)
274
275diff -aur gcc-3.4.0orig/gcc/cp/method.c gcc-3.4.0/gcc/cp/method.c
276--- gcc-3.4.0orig/gcc/cp/method.c 2004-04-08 23:15:58.000000000 +0100
277+++ gcc-3.4.0/gcc/cp/method.c 2004-05-09 08:10:52.000000000 +0100
278@@ -394,6 +394,7 @@
279 rewrite. */
280 TREE_PUBLIC (thunk_fndecl) = TREE_PUBLIC (function);
281 DECL_VISIBILITY (thunk_fndecl) = DECL_VISIBILITY (function);
282+ DECL_VISIBILITYSPECIFIED (thunk_fndecl) = DECL_VISIBILITYSPECIFIED (function);
283
284 if (flag_syntax_only)
285 {
286
287diff -aur gcc-3.4.0orig/gcc/cp/optimize.c gcc-3.4.0/gcc/cp/optimize.c
288--- gcc-3.4.0orig/gcc/cp/optimize.c 2004-02-08 01:52:50.000000000 +0000
289+++ gcc-3.4.0/gcc/cp/optimize.c 2004-05-09 08:10:52.000000000 +0100
290@@ -155,6 +155,7 @@
291 DECL_NOT_REALLY_EXTERN (clone) = DECL_NOT_REALLY_EXTERN (fn);
292 TREE_PUBLIC (clone) = TREE_PUBLIC (fn);
293 DECL_VISIBILITY (clone) = DECL_VISIBILITY (fn);
294+ DECL_VISIBILITYSPECIFIED (clone) = DECL_VISIBILITYSPECIFIED (fn);
295
296 /* Adjust the parameter names and locations. */
297 parm = DECL_ARGUMENTS (fn);
298
299diff -aur gcc-3.4.0orig/gcc/cp/rtti.c gcc-3.4.0/gcc/cp/rtti.c
300--- gcc-3.4.0orig/gcc/cp/rtti.c 2004-03-08 23:00:26.000000000 +0000
301+++ gcc-3.4.0/gcc/cp/rtti.c 2004-05-10 21:09:21.000000000 +0100
302@@ -361,7 +361,11 @@
303 pushdecl_top_level_and_finish (d, NULL_TREE);
304
305 if (CLASS_TYPE_P (type))
306- CLASSTYPE_TYPEINFO_VAR (TYPE_MAIN_VARIANT (type)) = d;
307+ {
308+ CLASSTYPE_TYPEINFO_VAR (TYPE_MAIN_VARIANT (type)) = d;
309+ DECL_VISIBILITY (d) = CLASSTYPE_VISIBILITY (type);
310+ DECL_VISIBILITYSPECIFIED (d) = CLASSTYPE_VISIBILITYSPECIFIED (type);
311+ }
312
313 /* Remember the type it is for. */
314 TREE_TYPE (name) = type;
315@@ -759,6 +763,11 @@
316 TREE_STATIC (name_decl) = 1;
317 DECL_EXTERNAL (name_decl) = 0;
318 TREE_PUBLIC (name_decl) = 1;
319+ if (CLASS_TYPE_P (target))
320+ {
321+ DECL_VISIBILITY (name_decl) = CLASSTYPE_VISIBILITY (target);
322+ DECL_VISIBILITYSPECIFIED (name_decl) = CLASSTYPE_VISIBILITYSPECIFIED (target);
323+ }
324 import_export_tinfo (name_decl, target, typeinfo_in_lib_p (target));
325 /* External name of the string containing the type's name has a
326 special name. */
327
328diff -aur gcc-3.4.0orig/gcc/c-pragma.c gcc-3.4.0/gcc/c-pragma.c
329--- gcc-3.4.0orig/gcc/c-pragma.c 2004-01-23 23:35:53.000000000 +0000
330+++ gcc-3.4.0/gcc/c-pragma.c 2004-05-09 08:10:52.000000000 +0100
331@@ -480,6 +480,86 @@
332 return asmname;
333 }
334
335+
336+#ifdef HANDLE_PRAGMA_VISIBILITY
337+static void handle_pragma_visibility (cpp_reader *);
338+
339+/* Sets the default visibility for symbols to something other than that
340+ specified on the command line. */
341+static void
342+handle_pragma_visibility (cpp_reader *dummy ATTRIBUTE_UNUSED)
343+{ /* Form is #pragma GCC visibility push(hidden)|pop */
344+ static int visstack [16], visidx;
345+ tree x;
346+ enum cpp_ttype token;
347+ enum { bad, push, pop } action = bad;
348+
349+ token = c_lex (&x);
350+ if (token == CPP_NAME)
351+ {
352+ const char *op = IDENTIFIER_POINTER (x);
353+ if (!strcmp (op, "push"))
354+ action = push;
355+ else if (!strcmp (op, "pop"))
356+ action = pop;
357+ }
358+ if (bad == action)
359+ GCC_BAD ("#pragma GCC visibility must be followed by push or pop");
360+ else
361+ {
362+ if (pop == action)
363+ {
364+ if (!visidx)
365+ {
366+ GCC_BAD ("No matching push for '#pragma GCC visibility pop'");
367+ }
368+ else
369+ {
370+ default_visibility = visstack[--visidx];
371+ visibility_options.inpragma = (visidx>0);
372+ }
373+ }
374+ else
375+ {
376+ if (c_lex (&x) != CPP_OPEN_PAREN)
377+ GCC_BAD ("missing '(' after '#pragma GCC visibility push' - ignored");
378+ token = c_lex (&x);
379+ if (token != CPP_NAME)
380+ {
381+ GCC_BAD ("malformed #pragma GCC visibility push");
382+ }
383+ else if (visidx >= 16)
384+ {
385+ GCC_BAD ("No more than sixteen #pragma GCC visibility pushes allowed at once");
386+ }
387+ else
388+ {
389+ const char *str = IDENTIFIER_POINTER (x);
390+ visstack[visidx++] = default_visibility;
391+ if (!strcmp (str, "default"))
392+ default_visibility = VISIBILITY_DEFAULT;
393+ else if (!strcmp (str, "internal"))
394+ default_visibility = VISIBILITY_INTERNAL;
395+ else if (!strcmp (str, "hidden"))
396+ default_visibility = VISIBILITY_HIDDEN;
397+ else if (!strcmp (str, "protected"))
398+ default_visibility = VISIBILITY_PROTECTED;
399+ else
400+ {
401+ GCC_BAD ("#pragma GCC visibility push() must specify default, internal, hidden or protected");
402+ }
403+ visibility_options.inpragma = 1;
404+ }
405+ if (c_lex (&x) != CPP_CLOSE_PAREN)
406+ GCC_BAD ("missing '(' after '#pragma GCC visibility push' - ignored");
407+ }
408+ }
409+ if (c_lex (&x) != CPP_EOF)
410+ warning ("junk at end of '#pragma GCC visibility'");
411+}
412+
413+#endif
414+
415 /* Front-end wrapper for pragma registration to avoid dragging
416 cpplib.h in almost everywhere. */
417 void
418@@ -505,6 +585,9 @@
419 #ifdef HANDLE_PRAGMA_EXTERN_PREFIX
420 c_register_pragma (0, "extern_prefix", handle_pragma_extern_prefix);
421 #endif
422+#ifdef HANDLE_PRAGMA_VISIBILITY
423+ c_register_pragma ("GCC", "visibility", handle_pragma_visibility);
424+#endif
425
426 #ifdef REGISTER_TARGET_PRAGMAS
427 REGISTER_TARGET_PRAGMAS ();
428diff -aur gcc-3.4.0orig/gcc/c-pragma.h gcc-3.4.0/gcc/c-pragma.h
429--- gcc-3.4.0orig/gcc/c-pragma.h 2004-01-31 06:18:05.000000000 +0000
430+++ gcc-3.4.0/gcc/c-pragma.h 2004-05-09 08:10:53.000000000 +0100
431@@ -44,6 +44,11 @@
432 #define HANDLE_PRAGMA_PACK 1
433 #endif /* HANDLE_PRAGMA_PACK_PUSH_POP */
434
435+/* It's safe to always leave visibility pragma enabled as if
436+ visibility is not supported on the host OS platform the
437+ statements are ignored. */
438+#define HANDLE_PRAGMA_VISIBILITY 1
439+
440 extern void init_pragma (void);
441
442 /* Front-end wrapper for pragma registration to avoid dragging
443
444
445diff -aur gcc-3.4.0orig/gcc/doc/invoke.texi gcc-3.4.0/gcc/doc/invoke.texi
446--- gcc-3.4.0orig/gcc/doc/invoke.texi 2004-04-19 00:05:36.000000000 +0100
447+++ gcc-3.4.0/gcc/doc/invoke.texi 2004-05-28 21:29:36.000000000 +0100
448@@ -183,7 +183,8 @@
449 -fno-optional-diags -fpermissive @gol
450 -frepo -fno-rtti -fstats -ftemplate-depth-@var{n} @gol
451 -fuse-cxa-atexit -fno-weak -nostdinc++ @gol
452--fno-default-inline -Wabi -Wctor-dtor-privacy @gol
453+-fno-default-inline -fvisibility-inlines-hidden @gol
454+-Wabi -Wctor-dtor-privacy @gol
455 -Wnon-virtual-dtor -Wreorder @gol
456 -Weffc++ -Wno-deprecated @gol
457 -Wno-non-template-friend -Wold-style-cast @gol
458@@ -674,7 +675,8 @@
459 -fargument-alias -fargument-noalias @gol
460 -fargument-noalias-global -fleading-underscore @gol
461 -ftls-model=@var{model} @gol
462--ftrapv -fwrapv -fbounds-check}
463+-ftrapv -fwrapv -fbounds-check @gol
464+-fvisibility}
465 @end table
466
467 @menu
468@@ -1433,6 +1435,20 @@
469 destructors, but will only work if your C library supports
470 @code{__cxa_atexit}.
471
472+@item -fvisibility-inlines-hidden
473+@opindex fvisibility-inlines-hidden
474+Causes all inlined methods to be marked with
475+@code{__attribute__ ((visibility ("hidden")))} so that they do not
476+appear in the export table of a DSO and do not require a PLT indirection
477+when used within the DSO. Enabling this option can have a dramatic effect
478+on load and link times of a DSO as it massively reduces the size of the
479+dynamic export table when the library makes heavy use of templates. While
480+it can cause bloating through duplication of code within each DSO where
481+it is used, often the wastage is less than the considerable space occupied
482+by a long symbol name in the export table which is typical when using
483+templates and namespaces. For even more savings, combine with the
484+@code{-fvisibility=hidden} switch.
485+
486 @item -fno-weak
487 @opindex fno-weak
488 Do not use weak symbol support, even if it is provided by the linker.
489@@ -11198,6 +11214,54 @@
490
491 The default without @option{-fpic} is @code{initial-exec}; with
492 @option{-fpic} the default is @code{global-dynamic}.
493+
494+@item -fvisibility=@var{default|internal|hidden|protected}
495+@opindex fvisibility
496+Set the default ELF image symbol visibility to the specified option - all
497+symbols will be marked with this unless overrided within the code.
498+Using this feature can very substantially improve linking and
499+load times of shared object libraries, produce more optimised
500+code, provide near-perfect API export and prevent symbol clashes.
501+It is @strong{strongly} recommended that you use this in any shared objects
502+you distribute.
503+
504+Despite the nomenclature, @code{default} always means public ie;
505+available to be linked against from outside the shared object.
506+@code{protected} and @code{internal} are pretty useless in real-world
507+usage so the only other commonly used option will be @code{hidden}.
508+The default if -fvisibility isn't specified is @code{default} ie; make every
509+symbol public - this causes the same behaviour as previous versions of
510+GCC.
511+
512+A good explanation of the benefits offered by ensuring ELF
513+symbols have the correct visibility is given by ``How To Write
514+Shared Libraries'' by Ulrich Drepper (which can be found at
515+@w{@uref{http://people.redhat.com/~drepper/}}) - however a superior
516+solution made possible by this option to marking things hidden when
517+the default is public is to make the default hidden and mark things
518+public. This is the norm with DLL's on Windows and with @option{-fvisibility=hidden}
519+and @code{__attribute__ ((visibility("default")))} instead of
520+@code{__declspec(dllexport)} you get almost identical semantics with
521+identical syntax. This is a great boon to those working with
522+cross-platform projects.
523+
524+For those adding visibility support to existing code, you may find
525+@samp{#pragma GCC visibility} of use. This works by you enclosing
526+the declarations you wish to set visibility for with (for example)
527+@samp{#pragma GCC visibility push(hidden)} and
528+@samp{#pragma GCC visibility pop}. These can be nested up to sixteen
529+times. Bear in mind that symbol visibility should be viewed @strong{as
530+part of the API interface contract} and thus all new code should
531+always specify visibility when it is not the default ie; declarations
532+only for use within the local DSO should @strong{always} be marked explicitly
533+as hidden as so to avoid PLT indirection overheads - making this
534+abundantly clear also aids readability and self-documentation of the code.
535+Note that due to ISO C++ specification requirements, operator new and
536+operator delete must always be of default visibility.
537+
538+An overview of these techniques, their benefits and how to use them
539+is at @w{@uref{http://www.nedprod.com/programs/gccvisibility.html}}.
540+
541 @end table
542
543 @c man end
544
545diff -aur gcc-3.4.0orig/gcc/flags.h gcc-3.4.0/gcc/flags.h
546--- gcc-3.4.0orig/gcc/flags.h 2004-02-18 00:09:04.000000000 +0000
547+++ gcc-3.4.0/gcc/flags.h 2004-05-09 08:10:53.000000000 +0100
548@@ -60,6 +60,30 @@
549 /* Nonzero means emit debugging information only for symbols which are used. */
550 extern int flag_debug_only_used_symbols;
551
552+/* Enumerate visibility settings. */
553+#ifndef SYMBOL_VISIBILITY_DEFINED
554+#define SYMBOL_VISIBILITY_DEFINED
555+enum symbol_visibility
556+{
557+ VISIBILITY_DEFAULT,
558+ VISIBILITY_INTERNAL,
559+ VISIBILITY_HIDDEN,
560+ VISIBILITY_PROTECTED
561+};
562+#endif
563+
564+/* The default visibility for all symbols (unless overridden). */
565+extern enum symbol_visibility default_visibility;
566+
567+struct visibility_flags
568+{
569+ unsigned inpragma : 1; /* True when in #pragma GCC visibility. */
570+ unsigned inlineshidden : 1; /* True when -finlineshidden in effect. */
571+};
572+
573+/* Global visibility options. */
574+extern struct visibility_flags visibility_options;
575+
576 /* Nonzero means do optimizations. -opt. */
577
578 extern int optimize;
579
580diff -aur gcc-3.4.0orig/gcc/opts.c gcc-3.4.0/gcc/opts.c
581--- gcc-3.4.0orig/gcc/opts.c 2004-02-18 00:09:04.000000000 +0000
582+++ gcc-3.4.0/gcc/opts.c 2004-05-09 08:10:53.000000000 +0100
583@@ -142,6 +142,12 @@
584 write_symbols is set to DBX_DEBUG, XCOFF_DEBUG, or DWARF_DEBUG. */
585 bool use_gnu_debug_info_extensions;
586
587+/* The default visibility for all symbols (unless overridden) */
588+enum symbol_visibility default_visibility = VISIBILITY_DEFAULT;
589+
590+/* Global visibility options. */
591+struct visibility_flags visibility_options;
592+
593 /* Columns of --help display. */
594 static unsigned int columns = 80;
595
596@@ -1440,6 +1446,21 @@
597 flag_verbose_asm = value;
598 break;
599
600+ case OPT_fvisibility_:
601+ {
602+ if(!strcmp(arg, "default"))
603+ default_visibility=VISIBILITY_DEFAULT;
604+ else if(!strcmp(arg, "internal"))
605+ default_visibility=VISIBILITY_INTERNAL;
606+ else if(!strcmp(arg, "hidden"))
607+ default_visibility=VISIBILITY_HIDDEN;
608+ else if(!strcmp(arg, "protected"))
609+ default_visibility=VISIBILITY_PROTECTED;
610+ else
611+ error("unrecognised visibility value \"%s\"", arg);
612+ }
613+ break;
614+
615 case OPT_fweb:
616 flag_web = value;
617 break;
618
619diff -aur gcc-3.4.0orig/gcc/tree.c gcc-3.4.0/gcc/tree.c
620--- gcc-3.4.0orig/gcc/tree.c 2004-02-05 22:01:35.000000000 +0000
621+++ gcc-3.4.0/gcc/tree.c 2004-05-10 15:22:52.000000000 +0100
622@@ -2563,6 +2563,11 @@
623 layout_decl (t, 0);
624 else if (code == FUNCTION_DECL)
625 DECL_MODE (t) = FUNCTION_MODE;
626+
627+ /* Set default visibility to whatever the user supplied with
628+ visibility_specified depending on #pragma GCC visibility. */
629+ DECL_VISIBILITY (t) = default_visibility;
630+ DECL_VISIBILITYSPECIFIED (t) = visibility_options.inpragma;
631
632 return t;
633 }
634
635diff -aur gcc-3.4.0orig/gcc/tree.h gcc-3.4.0/gcc/tree.h
636--- gcc-3.4.0orig/gcc/tree.h 2004-02-08 01:52:43.000000000 +0000
637+++ gcc-3.4.0/gcc/tree.h 2004-05-09 08:10:54.000000000 +0100
638@@ -1499,6 +1499,10 @@
639 /* Value of the decls's visibility attribute */
640 #define DECL_VISIBILITY(NODE) (DECL_CHECK (NODE)->decl.visibility)
641
642+/* Nonzero means that the decl had its visibility specified rather than
643+ being inferred. */
644+#define DECL_VISIBILITYSPECIFIED(NODE) (DECL_CHECK (NODE)->decl.visibility_specified)
645+
646 /* In a FUNCTION_DECL, nonzero if the function cannot be inlined. */
647 #define DECL_UNINLINABLE(NODE) (FUNCTION_DECL_CHECK (NODE)->decl.uninlinable)
648
649@@ -1633,7 +1637,8 @@
650 || TREE_CODE (DECL_CONTEXT (EXP)) == TRANSLATION_UNIT_DECL)
651
652 /* Enumerate visibility settings. */
653-
654+#ifndef SYMBOL_VISIBILITY_DEFINED
655+#define SYMBOL_VISIBILITY_DEFINED
656 enum symbol_visibility
657 {
658 VISIBILITY_DEFAULT,
659@@ -1641,6 +1646,7 @@
660 VISIBILITY_HIDDEN,
661 VISIBILITY_PROTECTED
662 };
663+#endif
664
665 struct function;
666
667@@ -1684,8 +1690,7 @@
668 unsigned thread_local_flag : 1;
669 unsigned declared_inline_flag : 1;
670 ENUM_BITFIELD(symbol_visibility) visibility : 2;
671- unsigned unused : 1;
672- /* one unused bit. */
673+ unsigned visibility_specified : 1;
674
675 unsigned lang_flag_0 : 1;
676 unsigned lang_flag_1 : 1;
677
678diff -aur gcc-3.4.0orig/gcc/varasm.c gcc-3.4.0/gcc/varasm.c
679--- gcc-3.4.0orig/gcc/varasm.c 2004-04-14 22:14:08.000000000 +0100
680+++ gcc-3.4.0/gcc/varasm.c 2004-05-09 08:10:54.000000000 +0100
681@@ -5150,8 +5150,8 @@
682 /* Static variables are always local. */
683 else if (! TREE_PUBLIC (exp))
684 local_p = true;
685- /* A variable is local if the user tells us so. */
686- else if (DECL_VISIBILITY (exp) != VISIBILITY_DEFAULT)
687+ /* A variable is local if the user explicitly tells us so. */
688+ else if (DECL_VISIBILITYSPECIFIED (exp) && DECL_VISIBILITY (exp) != VISIBILITY_DEFAULT)
689 local_p = true;
690 /* Otherwise, variables defined outside this object may not be local. */
691 else if (DECL_EXTERNAL (exp))
692@@ -5159,6 +5159,9 @@
693 /* Linkonce and weak data are never local. */
694 else if (DECL_ONE_ONLY (exp) || DECL_WEAK (exp))
695 local_p = false;
696+ /* If none of the above and visibility is not default, make local. */
697+ else if (DECL_VISIBILITY (exp) != VISIBILITY_DEFAULT)
698+ local_p = true;
699 /* If PIC, then assume that any global name can be overridden by
700 symbols resolved from other modules. */
701 else if (shlib)
702
GNU Compiler Collection: the C compiler and shared files
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