* tree.h (save_eptr, save_filt): Now file scoped statics.

        (honor_protect_cleanup_actions): Only create save_eptr and
        save_filt if they do not already exist.
        (lower_eh_constructs): Wipe all knowledge of save_eptr and
        save_filt before returning.


git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@91613 138bc75d-0d04-0410-961f-82ee72b054a4

1 files changed, 27 insertions, 4 deletions

diff --git a/gcc/tree-eh.c b/gcc/tree-eh.c
index b7ed2edc387..08a8a0f19cb 100644
--- a/gcc/tree-eh.c
+++ b/gcc/tree-eh.c
@@ -37,6 +37,21 @@ Boston, MA 02111-1307, USA.  */
 #include "langhooks.h"
 #include "ggc.h"
 
+/* In some circumstances we have to save EH data around a nested
+   exception.  The EXC_PTR_EXPR and FILTER_EXPR values are saved
+   into these _DECL nodes.
+
+   We lazily create this pair of _DECL nodes once per function rather
+   than creating a new pair of _DECLs each time we need to save the
+   EXEC_PTR and FILTER.  This can save us literally thousands of _DECL
+   nodes when we have many inline destructors with an embedded try block.  
+
+   This is safe as we know the lifetime of the values in these _DECL nodes.
+   Their lifetimes also ensure that globbing these uses into a single
+   pair of _DECL nodes requires no additional PHI_NODEs or SSA_NAMEs when
+   compared to having a pair of _DECL nodes per inline destructor with
+   an embedded try block.  */
+static tree save_eptr, save_filt;
 
 /* Nonzero if we are using EH to handle cleanups.  */
 static int using_eh_for_cleanups_p = 0;
@@ -807,10 +822,13 @@ honor_protect_cleanup_actions (struct leh_state *outer_state,
      we never fallthru from this copy of the finally block.  */
   if (finally_may_fallthru)
     {
-      tree save_eptr, save_filt;
-
-      save_eptr = create_tmp_var (ptr_type_node, "save_eptr");
-      save_filt = create_tmp_var (integer_type_node, "save_filt");
+      /* If we have not created _DECLs for saving the EXC_PTR
+	 and FILTER_EXPR, create them now.  */
+      if (!save_eptr)
+	{
+	  save_eptr = create_tmp_var (ptr_type_node, "save_eptr");
+	  save_filt = create_tmp_var (integer_type_node, "save_filt");
+	}
 
       i = tsi_start (finally);
       x = build (EXC_PTR_EXPR, ptr_type_node);
@@ -1644,6 +1662,11 @@ lower_eh_constructs (void)
   htab_delete (finally_tree);
 
   collect_eh_region_array ();
+
+  /* Wipe the DECLs we use for saving the EXC_PTR and FILTER_EXPR
+     to ensure we create new ones for the next function.  */
+  save_eptr = NULL;
+  save_filt = NULL;
 }
 
 struct tree_opt_pass pass_lower_eh =