[GOOGLE] Assign discriminators for different callsites at a same line within one BB

[Dehao Chen]

This patch assigns discriminators for different callsites within the
same BB. This is needed for accurate profile attribution in AutoFDO.

Testing on going.

OK for google branches if test pass?

Thanks,
Dehao

Index: gcc/tree-cfg.c
===================================================================
--- gcc/tree-cfg.c (revision 201858)
+++ gcc/tree-cfg.c (working copy)
@@ -781,9 +781,25 @@ assign_discriminators (void)
     {
       edge e;
       edge_iterator ei;
+      gimple_stmt_iterator gsi;
       gimple last = last_stmt (bb);
       location_t locus = last ? gimple_location (last) : UNKNOWN_LOCATION;
+      location_t curr_locus = UNKNOWN_LOCATION;

+      for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); gsi_next (&gsi))
+ {
+  gimple stmt = gsi_stmt (gsi);
+  if (gimple_code (stmt) != GIMPLE_CALL)
+    continue;
+  if (curr_locus == UNKNOWN_LOCATION ||
+      !same_line_p (curr_locus, gimple_location (stmt)))
+    curr_locus = gimple_location (stmt);
+  else
+    gimple_set_location (stmt, location_with_discriminator (
+ gimple_location (stmt),
+ next_discriminator_for_locus (gimple_location (stmt))));
+ }
+
       if (locus == UNKNOWN_LOCATION)
  continue;