[GOOGLE] Add discriminator for inlined callsite

[Dehao Chen]

This patch emits discriminator for inlined callsite. This is important
when there are two inlined callsites in the same line.

Bootstrapped, testing on going.

OK for google branches?

Thanks,
Dehao

Index: gcc/dwarf2out.c
===================================================================
--- gcc/dwarf2out.c (revision 201632)
+++ gcc/dwarf2out.c (working copy)
@@ -18807,12 +18807,16 @@ gen_label_die (tree decl, dw_die_ref context_die)
 static inline void
 add_call_src_coords_attributes (tree stmt, dw_die_ref die)
 {
-  expanded_location s = expand_location (BLOCK_SOURCE_LOCATION (stmt));
+  location_t locus = BLOCK_SOURCE_LOCATION (stmt);
+  expanded_location s = expand_location (locus);

   if (dwarf_version >= 3 || !dwarf_strict)
     {
       add_AT_file (die, DW_AT_call_file, lookup_filename (s.file));
       add_AT_unsigned (die, DW_AT_call_line, s.line);
+      unsigned discr = get_discriminator_from_locus (locus);
+      if (discr != 0)
+ add_AT_unsigned (die, DW_AT_discr, discr);
     }
 }