fix 23221

[Richard Henderson <rth at redhat dot com>]

Here we simply need to emit a stack-protect epilogue before
invoking a tail call.  Existing code in stack_protect_epilogue
will make sure that block-reordering moves the __stack_chk_fail
call out of line.  Existing code in cross-jumping will unify
multiple calls to __stack_chk_fail in the case there are 
multiple tail calls in the function.

Tested on x86_64-linux.


r~


        * function.c (stack_protect_epilogue): Export.
        * tree.h (stack_protect_epilogue): Declare.
        * calls.c (expand_call): Call it.

Index: calls.c
===================================================================
RCS file: /cvs/gcc/gcc/gcc/calls.c,v
retrieving revision 1.398
diff -u -p -d -r1.398 calls.c
--- calls.c	26 Jul 2005 13:53:48 -0000	1.398
+++ calls.c	4 Aug 2005 03:55:40 -0000
@@ -2247,6 +2247,9 @@ expand_call (tree exp, rtx target, int i
       if (pass && (flags & (ECF_LIBCALL_BLOCK | ECF_MALLOC)))
 	start_sequence ();
 
+      if (pass == 0 && cfun->stack_protect_guard)
+	stack_protect_epilogue ();
+
       adjusted_args_size = args_size;
       /* Compute the actual size of the argument block required.  The variable
 	 and constant sizes must be combined, the size may have to be rounded,
Index: function.c
===================================================================
RCS file: /cvs/gcc/gcc/gcc/function.c,v
retrieving revision 1.639
diff -u -p -d -r1.639 function.c
--- function.c	3 Aug 2005 21:50:13 -0000	1.639
+++ function.c	4 Aug 2005 03:55:41 -0000
@@ -4013,7 +4013,7 @@ stack_protect_prologue (void)
 # define gen_stack_protect_test(x, y, z)	(gcc_unreachable (), NULL_RTX)
 #endif
 
-static void
+void
 stack_protect_epilogue (void)
 {
   tree guard_decl = targetm.stack_protect_guard ();
Index: tree.h
===================================================================
RCS file: /cvs/gcc/gcc/gcc/tree.h,v
retrieving revision 1.750
diff -u -p -d -r1.750 tree.h
--- tree.h	26 Jul 2005 02:56:44 -0000	1.750
+++ tree.h	4 Aug 2005 03:55:42 -0000
@@ -3908,6 +3908,7 @@ extern void dump_tree_statistics (void);
 extern void expand_function_end (void);
 extern void expand_function_start (tree);
 extern void stack_protect_prologue (void);
+extern void stack_protect_epilogue (void);
 extern void recompute_tree_invarant_for_addr_expr (tree);
 extern bool is_global_var (tree t);
 extern bool needs_to_live_in_memory (tree);