except.h (current_function_eh_stub_label): Declare.

        * except.h (current_function_eh_stub_label): Declare.
        (current_function_eh_old_stub_label): Declare.
        * function.h (struct function): New members eh_stub_label and
        eh_old_stub_label.
        * except.c (current_function_eh_stub_label): New variable.
        (current_function_eh_old_stub_label): New variable.
        (init_eh_for_function): Clear them.
        (save_eh_status): Save them.
        (restore_eh_status): Restore them.
        (expand_builtin_eh_stub): Set current_function_eh_stub_label.
        (expand_builtin_eh_stub_old): Set current_function_eh_old_stub_label.
        * flow.c (find_basic_blocks_1): When handling a REG_LABEL note, don't
        make an edge from the block that contains it to the block starting
        with the label if this label is one of the eh stub labels.
        If eh stub labels exist, show they are reachable from the last block
        in the function.

From-SVN: r22369

1 files changed, 26 insertions, 4 deletions

diff --git a/gcc/flow.c b/gcc/flow.c
index 715555d..af9eb1c 100644
--- a/gcc/flow.c
+++ b/gcc/flow.c
@@ -484,7 +484,9 @@ find_basic_blocks_1 (f, nonlocal_label_list, live_reachable_p)
 	{
 	  /* Make a list of all labels referred to other than by jumps.  */
 	  for (note = REG_NOTES (insn); note; note = XEXP (note, 1))
-	    if (REG_NOTE_KIND (note) == REG_LABEL)
+	    if (REG_NOTE_KIND (note) == REG_LABEL
+		&& XEXP (note, 0) != current_function_eh_stub_label
+		&& XEXP (note, 0) != current_function_eh_old_stub_label)
 	      label_value_list = gen_rtx_EXPR_LIST (VOIDmode, XEXP (note, 0),
 						    label_value_list);
 	}
@@ -589,7 +591,6 @@ find_basic_blocks_1 (f, nonlocal_label_list, live_reachable_p)
 		  {
 		    if (GET_RTX_CLASS (GET_CODE (insn)) == 'i')
 		      {
-			
 			/* References to labels in non-jumping insns have
 			   REG_LABEL notes attached to them.
 
@@ -609,12 +610,17 @@ find_basic_blocks_1 (f, nonlocal_label_list, live_reachable_p)
 			   associated insns aren't marked dead, so we make
 			   the block in question live and create an edge from
 			   this insn to the label.  This is not strictly
-			   correct, but it is close enough for now.  */
+			   correct, but it is close enough for now.  
+
+			   See below for code that handles the eh_stub labels
+			   specially.  */
 			for (note = REG_NOTES (insn);
 			     note;
 			     note = XEXP (note, 1))
 			  {
-			    if (REG_NOTE_KIND (note) == REG_LABEL)
+			    if (REG_NOTE_KIND (note) == REG_LABEL
+				&& XEXP (note, 0) != current_function_eh_stub_label
+				&& XEXP (note, 0) != current_function_eh_old_stub_label)
 			      {
 				x = XEXP (note, 0);
 				block_live[BLOCK_NUM (x)] = 1;
@@ -695,6 +701,22 @@ find_basic_blocks_1 (f, nonlocal_label_list, live_reachable_p)
 			  }
 		      }
 		  }
+		/* We know something about the structure of the function
+		   __throw in libgcc2.c.  It is the only function that ever
+		   contains eh_stub labels.  It modifies its return address
+		   so that the last block returns to one of the eh_stub labels
+		   within it.  So we have to make additional edges in the
+		   flow graph.  */
+		if (i + 1 == n_basic_blocks
+		    && current_function_eh_stub_label != 0)
+		  {
+		    mark_label_ref (gen_rtx_LABEL_REF (VOIDmode,
+						       current_function_eh_stub_label),
+				    basic_block_end[i], 0);
+		    mark_label_ref (gen_rtx_LABEL_REF (VOIDmode,
+						       current_function_eh_old_stub_label),
+				    basic_block_end[i], 0);
+		  }
 	      }
 	}