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Patch tree-profile.c to support profile-func-internal-id parameter


This patch is for svn://gcc.gnu.org/svn/gcc/branches/google/gcc-4_9.  I add
support for the profile_func_internal-id in the instrumentation generated for
__coverage_callback.

Add support for the profile-func-internal-id parameter to the coverage callback.
Without this change, the function identifier passed to __coverage_callback
(enabled with param=coverage-callback=1) does not match the values emitted in
the .gcno file.  Because the function profile_id is typically more unique
(typically 32 bits) than the function internal id (typically 16 bits), it can be
desirable to have the profile_id used to identify a function as opposed to the
function internal id.

I've instrumented a large binary creating over 500 .gcno files and confirmed
that function IDs in these .gcno files match the IDs in __coverage_callback.  In
my example, there were typically about one to four functions sharing the same
internal function ID.  There were no collisions using profile_id.


Index: gcc/tree-profile.c
===================================================================
--- gcc/tree-profile.c (revision 226647)
+++ gcc/tree-profile.c (working copy)
@@ -864,8 +864,20 @@ gimple_gen_edge_profiler (int edgeno, edge e)
     {
       gimple call;
       tree tree_edgeno = build_int_cst (gcov_type_node, edgeno);
-      tree tree_uid = build_int_cst (gcov_type_node,
+
+      tree tree_uid;
+      if (PARAM_VALUE (PARAM_PROFILE_FUNC_INTERNAL_ID))
+        {
+          tree_uid  = build_int_cst (gcov_type_node,
                                      current_function_funcdef_no);
+        }
+      else
+        {
+          gcc_assert (coverage_node_map_initialized_p ());
+
+          tree_uid = build_int_cst
+      (gcov_type_node, cgraph_get_node (current_function_decl)->profile_id);
+        }
       tree callback_fn_type
               = build_function_type_list (void_type_node,
                                           gcov_type_node,


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