1 files changed, 101 insertions, 45 deletions

diff --git a/gcc/varasm.c b/gcc/varasm.c
index cc05c18..bbebd87 100644
--- a/gcc/varasm.c
+++ b/gcc/varasm.c
@@ -5504,12 +5504,6 @@ do_assemble_alias (tree decl, tree target)
 #endif
 }
 
-/* Derived type for use by compute_visible_aliases and callers.  A symbol
-   alias set is a pointer set into which we enter IDENTIFIER_NODES bearing
-   the canonicalised assembler-level symbol names corresponding to decls
-   and their aliases.  */
-
-typedef struct pointer_set_t symbol_alias_set_t;
 
 /* Allocate and construct a symbol alias set.  */
 
@@ -5521,7 +5515,7 @@ symbol_alias_set_create (void)
 
 /* Destruct and free a symbol alias set.  */
 
-static void
+void
 symbol_alias_set_destroy (symbol_alias_set_t *aset)
 {
   pointer_set_destroy (aset);
@@ -5529,7 +5523,7 @@ symbol_alias_set_destroy (symbol_alias_set_t *aset)
 
 /* Test if a symbol alias set contains a given name.  */
 
-static int
+int
 symbol_alias_set_contains (const symbol_alias_set_t *aset, tree t)
 {
   /* We accept either a DECL or an IDENTIFIER directly.  */
@@ -5551,40 +5545,110 @@ symbol_alias_set_insert (symbol_alias_set_t *aset, tree t)
   return pointer_set_insert (aset, t);
 }
 
-/* Compute the set of indentifier nodes that is generated by aliases
-   whose targets are reachable.  */
+/* IN_SET_P is a predicate function assuming to be taken
+   alias_pair->decl, alias_pair->target and DATA arguments.
+
+   Compute set of aliases by including everything where TRIVIALLY_VISIBLE
+   predeicate is true and propagate across aliases such that when
+   alias DECL is included, its TARGET is included too.  */
 
 static symbol_alias_set_t *
-compute_visible_aliases (void)
+propagate_aliases_forward (bool (*in_set_p)
+			     (tree decl, tree target, void *data),
+		           void *data)
 {
-  symbol_alias_set_t *visible;
+  symbol_alias_set_t *set;
   unsigned i;
   alias_pair *p;
   bool changed;
 
-  /* We have to compute the set of visible nodes including aliases
+  set = symbol_alias_set_create ();
+  for (i = 0; VEC_iterate (alias_pair, alias_pairs, i, p); ++i)
+    if (in_set_p (p->decl, p->target, data))
+      symbol_alias_set_insert (set, p->decl);
+  do
+    {
+      changed = false;
+      for (i = 0; VEC_iterate (alias_pair, alias_pairs, i, p); ++i)
+	if (symbol_alias_set_contains (set, p->decl)
+	    && !symbol_alias_set_insert (set, p->target))
+	  changed = true;
+    }
+  while (changed);
+
+  return set;
+}
+
+/* Like propagate_aliases_forward but do backward propagation.  */
+
+symbol_alias_set_t *
+propagate_aliases_backward (bool (*in_set_p)
+			     (tree decl, tree target, void *data),
+		           void *data)
+{
+  symbol_alias_set_t *set;
+  unsigned i;
+  alias_pair *p;
+  bool changed;
+
+  /* We have to compute the set of set nodes including aliases
      themselves.  */
-  visible = symbol_alias_set_create ();
+  set = symbol_alias_set_create ();
+  for (i = 0; VEC_iterate (alias_pair, alias_pairs, i, p); ++i)
+    if (in_set_p (p->decl, p->target, data))
+      symbol_alias_set_insert (set, p->target);
   do
     {
       changed = false;
       for (i = 0; VEC_iterate (alias_pair, alias_pairs, i, p); ++i)
-	{
-	  struct cgraph_node *fnode = NULL;
-	  struct varpool_node *vnode = NULL;
-
-	  fnode = cgraph_node_for_asm (p->target);
-	  vnode = (fnode == NULL) ? varpool_node_for_asm (p->target) : NULL;
-	  if ((fnode
-	       || vnode
-	       || symbol_alias_set_contains (visible, p->target))
-	      && !symbol_alias_set_insert (visible, p->decl))
-	    changed = true;
-	}
+	if (symbol_alias_set_contains (set, p->target)
+	    && !symbol_alias_set_insert (set, p->decl))
+	  changed = true;
     }
   while (changed);
 
-  return visible;
+  return set;
+}
+/* See if the alias is trivially visible.  This means
+     1) alias is expoerted from the unit or
+     2) alias is used in the code.
+   We assume that unused cgraph/varpool nodes has been
+   removed.
+   Used as callback for propagate_aliases.  */
+
+static bool
+trivially_visible_alias (tree decl, tree target ATTRIBUTE_UNUSED,
+			 void *data ATTRIBUTE_UNUSED)
+{
+  struct cgraph_node *fnode = NULL;
+  struct varpool_node *vnode = NULL;
+
+  if (!TREE_PUBLIC (decl))
+    {
+      if (TREE_CODE (decl) == FUNCTION_DECL)
+	fnode = cgraph_get_node (decl);
+      else
+	vnode = varpool_get_node (decl);
+      return vnode || fnode;
+    }
+  else
+    return true;
+}
+
+/* See if the target of alias is defined in this unit.
+   Used as callback for propagate_aliases.  */
+
+static bool
+trivially_defined_alias (tree decl ATTRIBUTE_UNUSED,
+			 tree target,
+			 void *data ATTRIBUTE_UNUSED)
+{
+  struct cgraph_node *fnode = NULL;
+  struct varpool_node *vnode = NULL;
+
+  fnode = cgraph_node_for_asm (target);
+  vnode = (fnode == NULL) ? varpool_node_for_asm (target) : NULL;
+  return (fnode && fnode->analyzed) || (vnode && vnode->finalized);
 }
 
 /* Remove the alias pairing for functions that are no longer in the call
@@ -5602,23 +5666,15 @@ remove_unreachable_alias_pairs (void)
 
   /* We have to compute the set of visible nodes including aliases
      themselves.  */
-  visible = compute_visible_aliases ();
+  visible = propagate_aliases_forward (trivially_visible_alias, NULL);
 
   for (i = 0; VEC_iterate (alias_pair, alias_pairs, i, p); )
     {
-      if (!DECL_EXTERNAL (p->decl))
+      if (!DECL_EXTERNAL (p->decl)
+	  && !symbol_alias_set_contains (visible, p->decl))
 	{
-	  struct cgraph_node *fnode = NULL;
-	  struct varpool_node *vnode = NULL;
-	  fnode = cgraph_node_for_asm (p->target);
-	  vnode = (fnode == NULL) ? varpool_node_for_asm (p->target) : NULL;
-	  if (!fnode
-	      && !vnode
-	      && !symbol_alias_set_contains (visible, p->target))
-	    {
-	      VEC_unordered_remove (alias_pair, alias_pairs, i);
-	      continue;
-	    }
+	  VEC_unordered_remove (alias_pair, alias_pairs, i);
+	  continue;
 	}
 
       i++;
@@ -5634,16 +5690,16 @@ remove_unreachable_alias_pairs (void)
 void
 finish_aliases_1 (void)
 {
-  symbol_alias_set_t *visible;
+  symbol_alias_set_t *defined;
   unsigned i;
   alias_pair *p;
 
   if (alias_pairs == NULL)
     return;
 
-  /* We have to compute the set of visible nodes including aliases
+  /* We have to compute the set of defined nodes including aliases
      themselves.  */
-  visible = compute_visible_aliases ();
+  defined = propagate_aliases_backward (trivially_defined_alias, NULL);
 
   FOR_EACH_VEC_ELT (alias_pair, alias_pairs, i, p)
     {
@@ -5652,7 +5708,7 @@ finish_aliases_1 (void)
       target_decl = find_decl_and_mark_needed (p->decl, p->target);
       if (target_decl == NULL)
 	{
-	  if (symbol_alias_set_contains (visible, p->target))
+	  if (symbol_alias_set_contains (defined, p->target))
 	    continue;
 
 	  if (! (p->emitted_diags & ALIAS_DIAG_TO_UNDEF)
@@ -5678,7 +5734,7 @@ finish_aliases_1 (void)
 	}
     }
 
-  symbol_alias_set_destroy (visible);
+  symbol_alias_set_destroy (defined);
 }
 
 /* Second pass of completing pending aliases.  Emit the actual assembly.