[google] Fix bugs in sampled profile collection

[Easwaran Raman]

This fixes two issues with sampled profile collection. It delays
cleanup of instrumentation_to_be_sampled after all callgraph nodes
have been instrumented and prevents  gcov_sample_counter_decl and
gcov_sampling_rate_decl from being garbage collected.

 Ok for google/gcc-4_6 and google/main branches?

-Easwaran

2011-09-30  Easwaran Raman  <era...@google.com>

        * tree-profile.c (gcov_sample_counter_decl): Add GTY marker.
        (gcov_sampling_rate_decl): Likewise.
        (add_sampling_to_edge_counters): Do not free
        instrumentation_to_be_sampled.
        (cleanup_instrumentation_sampling): New function.
        (tree_profiling): Call cleanup_instrumentation_sampling at the end.

testsuite/ChangeLog.google-4_6:

2011-09-30  Easwaran Raman  <era...@google.com>

        * gcc.dg/sample-profile-generate-1.c: New test.

Index: gcc/testsuite/gcc.dg/sample-profile-generate-1.c
===================================================================
--- gcc/testsuite/gcc.dg/sample-profile-generate-1.c    (revision 0)
+++ gcc/testsuite/gcc.dg/sample-profile-generate-1.c    (revision 0)
@@ -0,0 +1,26 @@
+/* { dg-do compile} */
+/* { dg-options "-O2 -fprofile-generate -fprofile-generate-sampling" } */
+
+void foobar(int);
+
+void
+foo (void)
+{
+  int i;
+  for (i = 0; i < 100; i++)
+    {
+      foobar(i);
+    }
+}
+
+void
+bar (void)
+{
+  int i;
+  for (i = 0; i < 100; i++)
+    {
+      foobar(i);
+    }
+}
+
+/* { dg-final { cleanup-coverage-files } } */

Index: tree-profile.c
===================================================================
--- tree-profile.c      (revision 178897)
+++ tree-profile.c      (working copy)
@@ -163,10 +163,10 @@ init_ic_make_global_vars (void)
 static struct pointer_set_t *instrumentation_to_be_sampled = NULL;

 /* extern __thread gcov_unsigned_t __gcov_sample_counter  */
-static tree gcov_sample_counter_decl = NULL_TREE;
+static GTY(()) tree gcov_sample_counter_decl = NULL_TREE;

 /* extern gcov_unsigned_t __gcov_sampling_rate  */
-static tree gcov_sampling_rate_decl = NULL_TREE;
+static GTY(()) tree gcov_sampling_rate_decl = NULL_TREE;

 /* forward declaration.  */
 void gimple_init_instrumentation_sampling (void);
@@ -281,9 +281,13 @@ add_sampling_to_edge_counters (void)
             break;
           }
       }
+}

+static void
+cleanup_instrumentation_sampling (void)
+{
   /* Free the bitmap.  */
-  if (instrumentation_to_be_sampled)
+  if (flag_profile_generate_sampling && instrumentation_to_be_sampled)
     {
       pointer_set_destroy (instrumentation_to_be_sampled);
       instrumentation_to_be_sampled = NULL;
@@ -1452,6 +1456,7 @@ tree_profiling (void)
     }

   del_node_map();
+  cleanup_instrumentation_sampling();
   return 0;
 }