decl2.c (key_method): Break out from...

        * decl2.c (key_method): Break out from...
        (import_export_vtable, import_export_class): ...here.

        * decl.c (finish_function): Don't mess with flag_keep_inline_functions.
        * decl2.c (finish_vtable_vardecl): Don't check decl_function_context.

        * search.c (note_debug_info_needed, dfs_debug_mark,
        dfs_debug_unmarkedp): Uncomment.  Adjust for new scheme.
        * decl2.c (finish_vtable_vardecl): Call note_debug_info_needed.

From-SVN: r32319

4 files changed, 91 insertions, 117 deletions

diff --git a/gcc/cp/ChangeLog b/gcc/cp/ChangeLog
index 26f3733..b97b555 100644
--- a/gcc/cp/ChangeLog
+++ b/gcc/cp/ChangeLog
@@ -1,3 +1,15 @@
+2000-03-03  Jason Merrill  <jason@casey.cygnus.com>
+
+	* decl2.c (key_method): Break out from...
+	(import_export_vtable, import_export_class): ...here.
+
+	* decl.c (finish_function): Don't mess with flag_keep_inline_functions.
+	* decl2.c (finish_vtable_vardecl): Don't check decl_function_context.
+
+	* search.c (note_debug_info_needed, dfs_debug_mark, 
+	dfs_debug_unmarkedp): Uncomment.  Adjust for new scheme.
+	* decl2.c (finish_vtable_vardecl): Call note_debug_info_needed.
+
 2000-03-03  Nathan Sidwell  <nathan@codesourcery.com>
 
 	* decl.c (cp_finish_decl): Remove obsolete obstack comments, fix
diff --git a/gcc/cp/decl.c b/gcc/cp/decl.c
index 8c8fc32..c3d070d 100644
--- a/gcc/cp/decl.c
+++ b/gcc/cp/decl.c
@@ -13883,21 +13883,10 @@ finish_function (lineno, flags)
     {
       int returns_null;
       int returns_value;
-      int saved_flag_keep_inline_functions =
-	flag_keep_inline_functions;
 
       /* So we can tell if jump_optimize sets it to 1.  */
       can_reach_end = 0;
 
-      if (DECL_CONTEXT (fndecl) != NULL_TREE
-	  && decl_function_context (fndecl))
-	/* Trick rest_of_compilation into not deferring output of this
-	   function, even if it is inline, since the rtl_obstack for
-	   this function is the function_obstack of the enclosing
-	   function and will be deallocated when the enclosing
-	   function is gone.  See save_tree_status.  */
-	flag_keep_inline_functions = 1;
-
       /* Before we call rest_of_compilation (which will pop the
 	 CURRENT_FUNCTION), we must save these values.  */
       returns_null = current_function_returns_null;
@@ -13934,8 +13923,6 @@ finish_function (lineno, flags)
       if (function_depth > 1)
 	ggc_pop_context ();
 
-      flag_keep_inline_functions = saved_flag_keep_inline_functions;
-
       if (DECL_SAVED_INSNS (fndecl) && ! TREE_ASM_WRITTEN (fndecl))
 	{
 	  /* Set DECL_EXTERNAL so that assemble_external will be called as
diff --git a/gcc/cp/decl2.c b/gcc/cp/decl2.c
index b961f26..8e66bb6 100644
--- a/gcc/cp/decl2.c
+++ b/gcc/cp/decl2.c
@@ -92,6 +92,7 @@ static int generate_ctor_and_dtor_functions_for_priority
 static tree prune_vars_needing_no_initialization PARAMS ((tree));
 static void write_out_vars PARAMS ((tree));
 static void import_export_class	PARAMS ((tree));
+static tree key_method PARAMS ((tree));
 
 extern int current_class_depth;
 
@@ -2378,6 +2379,29 @@ maybe_make_one_only (decl)
     DECL_COMDAT (decl) = 1;
 }
 
+/* Returns the virtual function with which the vtable for TYPE is
+   emitted, or NULL_TREE if that heuristic is not applicable to TYPE.  */
+
+static tree
+key_method (type)
+     tree type;
+{
+  tree method;
+
+  if (TYPE_FOR_JAVA (type)
+      || CLASSTYPE_INTERFACE_KNOWN (type))
+    return NULL_TREE;
+
+  for (method = TYPE_METHODS (type); method != NULL_TREE;
+       method = TREE_CHAIN (method))
+    if (DECL_VINDEX (method) != NULL_TREE
+	&& ! DECL_THIS_INLINE (method)
+	&& ! DECL_PURE_VIRTUAL_P (method))
+      return method;
+
+  return NULL_TREE;
+}
+
 /* Set TREE_PUBLIC and/or DECL_EXTERN on the vtable DECL,
    based on TYPE and other static flags.
 
@@ -2409,21 +2433,8 @@ import_export_vtable (decl, type, final)
       /* We can only wait to decide if we have real non-inline virtual
 	 functions in our class, or if we come from a template.  */
 
-      int found = CLASSTYPE_TEMPLATE_INSTANTIATION (type);
-
-      if (! found && ! final)
-	{
-	  tree method;
-	  for (method = TYPE_METHODS (type); method != NULL_TREE;
-	       method = TREE_CHAIN (method))
-	    if (DECL_VINDEX (method) != NULL_TREE
-		&& ! DECL_THIS_INLINE (method)
-		&& ! DECL_PURE_VIRTUAL_P (method))
-	      {
-		found = 1;
-		break;
-	      }
-	}
+      int found = (CLASSTYPE_TEMPLATE_INSTANTIATION (type)
+		   || key_method (type));
 
       if (final || ! found)
 	{
@@ -2482,23 +2493,14 @@ import_export_class (ctype)
     import_export = -1;
 
   /* Base our import/export status on that of the first non-inline,
-     non-abstract virtual function, if any.  */
+     non-pure virtual function, if any.  */
   if (import_export == 0
       && TYPE_POLYMORPHIC_P (ctype)
       && ! CLASSTYPE_TEMPLATE_INSTANTIATION (ctype))
     {
-      tree method;
-      for (method = TYPE_METHODS (ctype); method != NULL_TREE;
-	   method = TREE_CHAIN (method))
-	{
-	  if (DECL_VINDEX (method) != NULL_TREE
-	      && !DECL_THIS_INLINE (method)
-	      && !DECL_PURE_VIRTUAL_P (method))
-	    {
-	      import_export = (DECL_REALLY_EXTERN (method) ? -1 : 1);
-	      break;
-	    }
-	}
+      tree method = key_method (ctype);
+      if (method)
+	import_export = (DECL_REALLY_EXTERN (method) ? -1 : 1);
     }
 
 #ifdef MULTIPLE_SYMBOL_SPACES
@@ -2552,8 +2554,7 @@ finish_vtable_vardecl (t, data)
   import_export_vtable (vars, ctype, 1);
 
   if (! DECL_EXTERNAL (vars)
-      && (DECL_NEEDED_P (vars)
-	  || (decl_function_context (vars) && TREE_USED (vars)))
+      && DECL_NEEDED_P (vars)
       && ! TREE_ASM_WRITTEN (vars))
     {
       if (TREE_TYPE (vars) == void_type_node)
@@ -2607,17 +2608,16 @@ finish_vtable_vardecl (t, data)
 
       /* Since we're writing out the vtable here, also write the debug 
 	 info.  */
-      if (TYPE_DECL_SUPPRESS_DEBUG (TYPE_MAIN_DECL (ctype)))
-	{
-	  TYPE_DECL_SUPPRESS_DEBUG (TYPE_NAME (ctype)) = 0;
-	  rest_of_type_compilation (ctype, toplevel_bindings_p ());
-	}
+      note_debug_info_needed (ctype);
 
       return 1;
     }
-  else if (!DECL_NEEDED_P (vars))
-    /* We don't know what to do with this one yet.  */
-    return 0;
+
+  /* If the references to this class' vtables were optimized away, still
+     emit the appropriate debugging information.  See dfs_debug_mark.  */
+  if (DECL_COMDAT (vars)
+      && CLASSTYPE_DEBUG_REQUESTED (ctype))
+    note_debug_info_needed (ctype);
 
   return 0;
 }
diff --git a/gcc/cp/search.c b/gcc/cp/search.c
index bc0ab26..9f8f5de 100644
--- a/gcc/cp/search.c
+++ b/gcc/cp/search.c
@@ -2571,15 +2571,6 @@ unmarked_pushdecls_p (binfo, data)
 #if 0
 static int dfs_search_slot_nonempty_p (binfo) tree binfo;
 { return CLASSTYPE_SEARCH_SLOT (BINFO_TYPE (binfo)) != 0; }
-
-static tree 
-dfs_debug_unmarkedp (binfo, data) 
-     tree binfo;
-     void *data ATTRIBUTE_UNUSED;
-{ 
-  return (!CLASSTYPE_DEBUG_REQUESTED (BINFO_TYPE (binfo)) 
-	  ? binfo : NULL_TREE);
-}
 #endif
 
 /* The worker functions for `dfs_walk'.  These do not need to
@@ -2639,36 +2630,6 @@ dfs_unmark_new_vtable (binfo) tree binfo;
 static void
 dfs_clear_search_slot (binfo) tree binfo;
 { CLASSTYPE_SEARCH_SLOT (BINFO_TYPE (binfo)) = 0; }
-
-/* Keep this code around in case we later want to control debug info
-   based on whether a type is "used".  Currently, we only suppress debug
-   info if we can emit it with the vtable.  jason 1999-11-11) */
-static tree
-dfs_debug_mark (binfo, data)
-     tree binfo;
-     void *data ATTRIBUTE_UNUSED;
-{
-  tree t = BINFO_TYPE (binfo);
-
-  CLASSTYPE_DEBUG_REQUESTED (t) = 1;
-
-  /* If interface info is known, either we've already emitted the debug
-     info or we don't need to.  */
-  if (CLASSTYPE_INTERFACE_KNOWN (t))
-    return NULL_TREE;
-
-  /* If the class has virtual functions, we'll emit the debug info
-     with the vtable.  */
-  if (TYPE_POLYMORPHIC_P (t))
-    return NULL_TREE;
-
-  /* We cannot rely on some alien method to solve our problems,
-     so we must write out the debug info ourselves.  */
-  TYPE_DECL_SUPPRESS_DEBUG (TYPE_NAME (t)) = 0;
-  rest_of_type_compilation (t, toplevel_bindings_p ());
-
-  return NULL_TREE;
-}
 #endif
 
 struct vbase_info 
@@ -3254,44 +3215,58 @@ maybe_suppress_debug_info (t)
   /* Otherwise, just emit the debug info normally.  */
 }
 
-#if 0
-/* Keep this code around in case we later want to control debug info
-   based on whether a type is "used".  Currently, we only suppress debug
-   info if we can emit it with the vtable.  jason 1999-11-11) */
+/* Note that we want debugging information for a base class of a class
+   whose vtable is being emitted.  Normally, this would happen because
+   calling the constructor for a derived class implies calling the
+   constructors for all bases, which involve initializing the
+   appropriate vptr with the vtable for the base class; but in the
+   presence of optimization, this initialization may be optimized
+   away, so we tell finish_vtable_vardecl that we want the debugging
+   information anyway.  */
+
+static tree
+dfs_debug_mark (binfo, data)
+     tree binfo;
+     void *data ATTRIBUTE_UNUSED;
+{
+  tree t = BINFO_TYPE (binfo);
+
+  CLASSTYPE_DEBUG_REQUESTED (t) = 1;
+
+  return NULL_TREE;
+}
+
+/* Returns BINFO if we haven't already noted that we want debugging
+   info for this base class.  */
+
+static tree 
+dfs_debug_unmarkedp (binfo, data) 
+     tree binfo;
+     void *data ATTRIBUTE_UNUSED;
+{ 
+  return (!CLASSTYPE_DEBUG_REQUESTED (BINFO_TYPE (binfo)) 
+	  ? binfo : NULL_TREE);
+}
 
-/* If we want debug info for a type TYPE, make sure all its base types
-   are also marked as being potentially interesting.  This avoids
-   the problem of not writing any debug info for intermediate basetypes
-   that have abstract virtual functions.  Also mark member types.  */
+/* Write out the debugging information for TYPE, whose vtable is being
+   emitted.  Also walk through our bases and note that we want to
+   write out information for them.  This avoids the problem of not
+   writing any debug info for intermediate basetypes whose
+   constructors, and thus the references to their vtables, and thus
+   the vtables themselves, were optimized away.  */
 
 void
 note_debug_info_needed (type)
      tree type;
 {
-  tree field;
-
-  if (current_template_parms)
-    return;
-    
-  if (TYPE_BEING_DEFINED (type))
-    /* We can't go looking for the base types and fields just yet.  */
+  if (! TYPE_DECL_SUPPRESS_DEBUG (TYPE_NAME (type)))
     return;
 
-  /* See the comment in maybe_suppress_debug_info.  */
-  if (write_symbols == DWARF_DEBUG || write_symbols == NO_DEBUG)
-    return;
+  TYPE_DECL_SUPPRESS_DEBUG (TYPE_NAME (type)) = 0;
+  rest_of_type_compilation (type, toplevel_bindings_p ());
 
   dfs_walk (TYPE_BINFO (type), dfs_debug_mark, dfs_debug_unmarkedp, 0);
-  for (field = TYPE_FIELDS (type); field; field = TREE_CHAIN (field))
-    {
-      tree ttype;
-      if (TREE_CODE (field) == FIELD_DECL
-	  && IS_AGGR_TYPE (ttype = target_type (TREE_TYPE (field)))
-	  && dfs_debug_unmarkedp (TYPE_BINFO (ttype), 0))
-	note_debug_info_needed (ttype);
-    }
 }
-#endif
 
 /* Subroutines of push_class_decls ().  */