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.


git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@115086 138bc75d-0d04-0410-961f-82ee72b054a4

1 files changed, 257 insertions, 63 deletions

diff --git a/gcc/cp/decl2.c b/gcc/cp/decl2.c
index 80fcc29cc56..0a12a380658 100644
--- a/gcc/cp/decl2.c
+++ b/gcc/cp/decl2.c
@@ -1533,6 +1533,110 @@ maybe_emit_vtables (tree ctype)
   return true;
 }
 
+/* A special return value from type_visibility meaning internal
+   linkage.  */
+
+enum { VISIBILITY_STATIC = VISIBILITY_INTERNAL+1 };
+
+/* walk_tree helper function for type_visibility.  */
+
+static tree
+min_vis_r (tree *tp, int *walk_subtrees, void *data)
+{
+  int *vis_p = (int *)data;
+  if (! TYPE_P (*tp))
+    {
+      *walk_subtrees = 0;
+    }
+  else if (CLASS_TYPE_P (*tp))
+    {
+      if (!TREE_PUBLIC (TYPE_MAIN_DECL (*tp)))
+	{
+	  *vis_p = VISIBILITY_STATIC;
+	  return *tp;
+	}
+      else if (CLASSTYPE_VISIBILITY (*tp) > *vis_p)
+	*vis_p = CLASSTYPE_VISIBILITY (*tp);
+    }
+  return NULL;
+}
+
+/* Returns the visibility of TYPE, which is the minimum visibility of its
+   component types.  */
+
+static int
+type_visibility (tree type)
+{
+  int vis = VISIBILITY_DEFAULT;
+  walk_tree_without_duplicates (&type, min_vis_r, &vis);
+  return vis;
+}
+
+/* Limit the visibility of DECL to VISIBILITY.  SPECIFIED is true if the
+   constraint comes from an attribute or pragma; REASON is the source of
+   the constraint.  */
+
+static bool
+constrain_visibility (tree decl, int visibility, bool specified,
+		      const char *reason)
+{
+  if (visibility == VISIBILITY_STATIC)
+    {
+      TREE_PUBLIC (decl) = 0;
+      DECL_INTERFACE_KNOWN (decl) = 1;
+      if (DECL_LANG_SPECIFIC (decl))
+	DECL_NOT_REALLY_EXTERN (decl) = 1;
+    }
+  else if (visibility > DECL_VISIBILITY (decl))
+    {
+      if (lookup_attribute ("visibility", DECL_ATTRIBUTES (decl)))
+	warning (OPT_Wattributes, "%q+D: visibility attribute requests "
+		 "greater visibility than its %s allows", decl, reason);
+      DECL_VISIBILITY (decl) = visibility;
+      if (!DECL_VISIBILITY_SPECIFIED (decl))
+	DECL_VISIBILITY_SPECIFIED (decl) = specified;
+      return true;
+    }
+  return false;
+}
+
+/* Constrain the visibility of DECL based on the visbility of its template
+   arguments.  */
+
+static void
+constrain_visibility_for_template (tree decl, tree targs)
+{
+  /* If this is a template instantiation, check the innermost
+     template args for visibility constraints.  The outer template
+     args are covered by the class check.  */
+  tree args = INNERMOST_TEMPLATE_ARGS (targs);
+  int i;
+  for (i = TREE_VEC_LENGTH (args); i > 0; --i)
+    {
+      int vis = 0;
+
+      tree arg = TREE_VEC_ELT (args, i-1);
+      if (TYPE_P (arg))
+	vis = type_visibility (arg);
+      else if (TREE_TYPE (arg) && POINTER_TYPE_P (TREE_TYPE (arg)))
+	{
+	  STRIP_NOPS (arg);
+	  if (TREE_CODE (arg) == ADDR_EXPR)
+	    arg = TREE_OPERAND (arg, 0);
+	  if (TREE_CODE (arg) == VAR_DECL
+	      || TREE_CODE (arg) == FUNCTION_DECL)
+	    {
+	      if (! TREE_PUBLIC (arg))
+		vis = VISIBILITY_STATIC;
+	      else
+		vis = DECL_VISIBILITY (arg);
+	    }
+	}
+      if (vis)
+	constrain_visibility (decl, vis, false, "template parameter");
+    }
+}
+
 /* Like c_determine_visibility, but with additional C++-specific
    behavior.
 
@@ -1544,12 +1648,18 @@ maybe_emit_vtables (tree ctype)
 
    Note that because namespaces have multiple independent definitions,
    namespace visibility is handled elsewhere using the #pragma visibility
-   machinery rather than by decorating the namespace declaration.  */
+   machinery rather than by decorating the namespace declaration.
+
+   The goal is for constraints from the type to give a diagnostic, and
+   other constraints to be applied silently.  */
 
 void
 determine_visibility (tree decl)
 {
-  tree class_type;
+  tree class_type = NULL_TREE;
+  bool use_template;
+
+  /* Remember that all decls get VISIBILITY_DEFAULT when built.  */
 
   /* Only relevant for names with external linkage.  */
   if (!TREE_PUBLIC (decl))
@@ -1560,9 +1670,30 @@ determine_visibility (tree decl)
      maybe_clone_body.  */
   gcc_assert (!DECL_CLONED_FUNCTION_P (decl));
 
-  /* Give the common code a chance to make a determination.  */
-  if (c_determine_visibility (decl))
-    return;
+  if (TREE_CODE (decl) == TYPE_DECL)
+    {
+      if (CLASS_TYPE_P (TREE_TYPE (decl)))
+	use_template = CLASSTYPE_USE_TEMPLATE (TREE_TYPE (decl));
+      else if (TYPE_TEMPLATE_INFO (TREE_TYPE (decl)))
+	use_template = 1;
+      else
+	use_template = 0;
+    }
+  else if (DECL_LANG_SPECIFIC (decl))
+    use_template = DECL_USE_TEMPLATE (decl);
+  else
+    use_template = 0;
+
+  /* Anything that is exported must have default visibility.  */
+  if (TARGET_DLLIMPORT_DECL_ATTRIBUTES
+      && lookup_attribute ("dllexport",
+			   TREE_CODE (decl) == TYPE_DECL
+			   ? TYPE_ATTRIBUTES (TREE_TYPE (decl))
+			   : DECL_ATTRIBUTES (decl)))
+    {
+      DECL_VISIBILITY (decl) = VISIBILITY_DEFAULT;
+      DECL_VISIBILITY_SPECIFIED (decl) = 1;
+    }
 
   /* If DECL is a member of a class, visibility specifiers on the
      class can influence the visibility of the DECL.  */
@@ -1574,6 +1705,8 @@ determine_visibility (tree decl)
     class_type = TREE_TYPE (DECL_NAME (decl));
   else
     {
+      /* Not a class member.  */
+
       /* Virtual tables have DECL_CONTEXT set to their associated class,
 	 so they are automatically handled above.  */
       gcc_assert (TREE_CODE (decl) != VAR_DECL
@@ -1581,77 +1714,138 @@ determine_visibility (tree decl)
 
       if (DECL_FUNCTION_SCOPE_P (decl))
 	{
+	  /* Local statics and classes get the visibility of their
+	     containing function.  */
 	  tree fn = DECL_CONTEXT (decl);
 	  DECL_VISIBILITY (decl) = DECL_VISIBILITY (fn);
 	  DECL_VISIBILITY_SPECIFIED (decl) = DECL_VISIBILITY_SPECIFIED (fn);
-	}
 
-      /* Entities not associated with any class just get the
-	 visibility specified by their attributes.  */
-      return;
+	  /* Local classes in templates have CLASSTYPE_USE_TEMPLATE set,
+	     but have no TEMPLATE_INFO, so don't try to check it.  */
+	  use_template = 0;
+	}
+      else if (TREE_CODE (decl) == VAR_DECL && DECL_TINFO_P (decl))
+	{
+	  /* tinfo visibility is based on the type it's for.  */
+	  constrain_visibility
+	    (decl, type_visibility (TREE_TYPE (DECL_NAME (decl))),
+	     false, "type");
+	}
+      else if (use_template)
+	/* Template instantiations and specializations get visibility based
+	   on their template unless they override it with an attribute.  */;
+      else if (! DECL_VISIBILITY_SPECIFIED (decl))
+	{
+	  /* Set default visibility to whatever the user supplied with
+	     #pragma GCC visibility or a namespace visibility attribute.  */
+	  DECL_VISIBILITY (decl) = default_visibility;
+	  DECL_VISIBILITY_SPECIFIED (decl) = visibility_options.inpragma;
+	}
     }
 
-  /* By default, static data members and function members receive
-     the visibility of their containing class.  */
-  if (class_type)
+  if (use_template)
     {
-      determine_visibility_from_class (decl, class_type);
-
-      /* Give the target a chance to override the visibility associated
-	 with DECL.  */
-      if (TREE_CODE (decl) == VAR_DECL
-	  && (DECL_TINFO_P (decl)
-	      || (DECL_VTABLE_OR_VTT_P (decl)
-		  /* Construction virtual tables are not exported because
-		     they cannot be referred to from other object files;
-		     their name is not standardized by the ABI.  */
-		  && !DECL_CONSTRUCTION_VTABLE_P (decl)))
-	  && TREE_PUBLIC (decl)
-	  && !DECL_REALLY_EXTERN (decl)
-	  && DECL_VISIBILITY_SPECIFIED (decl)
-	  && (!class_type || !CLASSTYPE_VISIBILITY_SPECIFIED (class_type)))
-	targetm.cxx.determine_class_data_visibility (decl);
+      tree tinfo = (TREE_CODE (decl) == TYPE_DECL
+		    ? TYPE_TEMPLATE_INFO (TREE_TYPE (decl))
+		    : DECL_TEMPLATE_INFO (decl));
+      tree args = TI_ARGS (tinfo);
+      int depth = TMPL_ARGS_DEPTH (args);
+
+      /* If the template has explicit visibility and the specialization
+	 doesn't, use the visibility from the template.  */
+      if (!DECL_VISIBILITY_SPECIFIED (decl))
+	{
+	  tree pattern = DECL_TEMPLATE_RESULT (TI_TEMPLATE (tinfo));
+	  DECL_VISIBILITY (decl) = DECL_VISIBILITY (pattern);
+	}
+
+      /* FIXME should TMPL_ARGS_DEPTH really return 1 for null input? */
+      if (args && depth > template_class_depth (class_type))
+	/* Don't let it have more visibility than its template type
+	   arguments.  */
+	constrain_visibility_for_template (decl, args);
     }
+  
+  if (class_type)
+    determine_visibility_from_class (decl, class_type);
+
+  /* Don't let it have more visibility than its type.  */
+  if (TREE_CODE (decl) != TYPE_DECL)
+    if (constrain_visibility (decl, type_visibility (TREE_TYPE (decl)),
+			      false, "type"))
+      warning (OPT_Wattributes, "\
+%q+D declared with greater visibility than its type",
+	       decl);
+
+  if (decl_anon_ns_mem_p (decl))
+    /* Names in an anonymous namespace get internal linkage.
+       This might change once we implement export.  */
+    constrain_visibility (decl, VISIBILITY_STATIC,
+			  false, "namespace");
 }
 
+/* By default, static data members and function members receive
+   the visibility of their containing class.  */
+
 static void
 determine_visibility_from_class (tree decl, tree class_type)
 {
-  if (TARGET_DLLIMPORT_DECL_ATTRIBUTES
-      && lookup_attribute ("dllexport", TYPE_ATTRIBUTES (class_type)))
-    {
-      DECL_VISIBILITY (decl) = VISIBILITY_DEFAULT;
-      DECL_VISIBILITY_SPECIFIED (decl) = 1;
-    }
-  else if (TREE_CODE (decl) == FUNCTION_DECL
-	   && DECL_DECLARED_INLINE_P (decl)
-	   && visibility_options.inlines_hidden)
-    {
-      /* Don't change it if it has been set explicitly by user.  */
-      if (!DECL_VISIBILITY_SPECIFIED (decl))
-	{
-	  DECL_VISIBILITY (decl) = VISIBILITY_HIDDEN;
-	  DECL_VISIBILITY_SPECIFIED (decl) = 1;
-	}
-    }
-  else if (CLASSTYPE_VISIBILITY_SPECIFIED (class_type))
-    {
-      DECL_VISIBILITY (decl) = CLASSTYPE_VISIBILITY (class_type);
-      DECL_VISIBILITY_SPECIFIED (decl) = 1;
-    }
-  else if (TYPE_CLASS_SCOPE_P (class_type))
-    determine_visibility_from_class (decl, TYPE_CONTEXT (class_type));
-  else if (TYPE_FUNCTION_SCOPE_P (class_type))
-    {
-      tree fn = TYPE_CONTEXT (class_type);
-      DECL_VISIBILITY (decl) = DECL_VISIBILITY (fn);
-      DECL_VISIBILITY_SPECIFIED (decl) = DECL_VISIBILITY_SPECIFIED (fn);
-    }
-  else if (!DECL_VISIBILITY_SPECIFIED (decl))
-    {
-      DECL_VISIBILITY (decl) = CLASSTYPE_VISIBILITY (class_type);
-      DECL_VISIBILITY_SPECIFIED (decl) = 0;
-    }
+  if (visibility_options.inlines_hidden
+      /* Don't do this for inline templates; specializations might not be
+	 inline, and we don't want them to inherit the hidden
+	 visibility.  We'll set it here for all inline instantiations.  */
+      && !processing_template_decl
+      && ! DECL_VISIBILITY_SPECIFIED (decl)
+      && TREE_CODE (decl) == FUNCTION_DECL
+      && DECL_DECLARED_INLINE_P (decl))
+    DECL_VISIBILITY (decl) = VISIBILITY_HIDDEN;
+
+  /* The decl can't have more visibility than its class.  */
+  constrain_visibility (decl, CLASSTYPE_VISIBILITY (class_type),
+			CLASSTYPE_VISIBILITY_SPECIFIED (class_type),
+			"class");
+
+  /* Give the target a chance to override the visibility associated
+     with DECL.  */
+  if (TREE_CODE (decl) == VAR_DECL
+      && (DECL_TINFO_P (decl)
+	  || (DECL_VTABLE_OR_VTT_P (decl)
+	      /* Construction virtual tables are not exported because
+		 they cannot be referred to from other object files;
+		 their name is not standardized by the ABI.  */
+	      && !DECL_CONSTRUCTION_VTABLE_P (decl)))
+      && TREE_PUBLIC (decl)
+      && !DECL_REALLY_EXTERN (decl)
+      && DECL_VISIBILITY_SPECIFIED (decl)
+      && (!class_type || !CLASSTYPE_VISIBILITY_SPECIFIED (class_type)))
+    targetm.cxx.determine_class_data_visibility (decl);
+}
+
+/* Constrain the visibility of a class TYPE based on the visibility of its
+   field types.  Warn if any fields require lesser visibility.  */
+
+void
+constrain_class_visibility (tree type)
+{
+  tree decl = TYPE_MAIN_DECL (type);
+  tree binfo = TYPE_BINFO (type);
+  tree t;
+  int i;
+
+  for (t = TYPE_FIELDS (type); t; t = TREE_CHAIN (t))
+    if (TREE_CODE (t) == FIELD_DECL)
+      if (constrain_visibility (decl, type_visibility (TREE_TYPE (t)),
+				false, "field type"))
+	warning (OPT_Wattributes, "\
+%qT declared with greater visibility than the type of its field %qD",
+		 type, t);
+
+  for (i = 0; BINFO_BASE_ITERATE (binfo, i, t); ++i)
+    if (constrain_visibility (decl, type_visibility (TREE_TYPE (t)),
+			      false, "base type"))
+      warning (OPT_Wattributes, "\
+%qT declared with greater visibility than its base %qT",
+	       type, TREE_TYPE (t));
 }
 
 /* DECL is a FUNCTION_DECL or VAR_DECL.  If the object file linkage