[GOOGLE] Fix dynamic instrumentation patching for cold sections

[Teresa Johnson]

This patch fixes the support for patching for instrumentation so that it
works with function splitting, by using the correct helper method for locating
the current section.

Added a couple tests cloned from existing function splitting tests that
I confirmed expose the problem.

Passes regression tests. Ok for google branches?

Thanks,
Teresa

2014-09-23  Teresa Johnson  <tejohn...@google.com>

        Google ref b/17608598.
        * config/i386/i386.c (ix86_output_function_nops_prologue_epilogue):
        Ensure we switch to correct section.
        * testsuite/gcc.dg/tree-prof/cold_partition_patch.c: New test.
        * testsuite/g++.dg/tree-prof/partition_patch.C: Ditto.

Index: config/i386/i386.c
===================================================================
--- config/i386/i386.c  (revision 215515)
+++ config/i386/i386.c  (working copy)
@@ -11946,7 +11946,7 @@ ix86_output_function_nops_prologue_epilogue (FILE
   fprintf (file, "\n");

   /* Switching back to text section.  */
-  switch_to_section (function_section (current_function_decl));
+  switch_to_section (current_function_section ());
   return true;
 }

Index: testsuite/gcc.dg/tree-prof/cold_partition_patch.c
===================================================================
--- testsuite/gcc.dg/tree-prof/cold_partition_patch.c   (revision 0)
+++ testsuite/gcc.dg/tree-prof/cold_partition_patch.c   (revision 0)
@@ -0,0 +1,38 @@
+/* Check if patching works with function splitting. */
+/* { dg-do compile { target x86_64-*-* } } */
+/* { dg-require-effective-target freorder } */
+/* { dg-options "-O2 -freorder-blocks-and-partition -save-temps
-mpatch-functions-for-instrumentation -fno-optimize-sibling-calls " }
*/
+
+#define SIZE 10000
+
+const char *sarr[SIZE];
+const char *buf_hot;
+const char *buf_cold;
+
+__attribute__((noinline))
+void
+foo (int path)
+{
+  int i;
+  if (path)
+    {
+      for (i = 0; i < SIZE; i++)
+       sarr[i] = buf_hot;
+    }
+  else
+    {
+      for (i = 0; i < SIZE; i++)
+       sarr[i] = buf_cold;
+    }
+}
+
+int
+main (int argc, char *argv[])
+{
+  buf_hot =  "hello";
+  buf_cold = "world";
+  foo (argc);
+  return 0;
+}
+
+/* { dg-final-use { cleanup-saved-temps } } */
Index: testsuite/g++.dg/tree-prof/partition_patch.C
===================================================================
--- testsuite/g++.dg/tree-prof/partition_patch.C        (revision 0)
+++ testsuite/g++.dg/tree-prof/partition_patch.C        (revision 0)
@@ -0,0 +1,19 @@
+// Check if patching works with function splitting.
+// { dg-do compile { target x86_64-*-* } }
+// { dg-require-effective-target freorder }
+// { dg-options "-O2 -fnon-call-exceptions
-freorder-blocks-and-partition -mpatch-functions-for-instrumentation
-fno-optimize-sibling-calls " }
+
+int k;
+
+int
+main ()
+{
+  try
+  {
+    if (k)
+      throw 6;
+  }
+  catch (...)
+  {
+  }
+}


-- 
Teresa Johnson | Software Engineer | tejohn...@google.com | 408-460-2413