+/* Trivial hash function for a location_t. ITEM is a pointer to
+ a hash table entry that maps a location_t to a discriminator. */
+
+static unsigned int
+locus_map_hash (const void *item)
+{
+ return ((const struct locus_discrim_map *) item)->locus;
+}
+
+/* Equality function for the locus-to-discriminator map. VA and VB
+ point to the two hash table entries to compare. */
+
+static int
+locus_map_eq (const void *va, const void *vb)
+{
+ const struct locus_discrim_map *a = (const struct locus_discrim_map *) va;
+ const struct locus_discrim_map *b = (const struct locus_discrim_map *) vb;
+ return a->locus == b->locus;
+}
+
+/* Find the next available discriminator value for LOCUS. The
+ discriminator distinguishes among several basic blocks that
+ share a common locus, allowing for more accurate sample-based
+ profiling. */
+
+static int
+next_discriminator_for_locus (location_t locus)
+{
+ struct locus_discrim_map item;
+ struct locus_discrim_map **slot;
+
+ item.locus = locus;
+ item.discriminator = 0;
+ slot = (struct locus_discrim_map **)
+ htab_find_slot_with_hash (discriminator_per_locus, (void *) &item,
+ (hashval_t) locus, INSERT);
+ gcc_assert (slot);
+ if (*slot == HTAB_EMPTY_ENTRY)
+ {
+ *slot = XNEW (struct locus_discrim_map);
+ gcc_assert (*slot);
+ (*slot)->locus = locus;
+ (*slot)->discriminator = 0;
+ }
+ (*slot)->discriminator++;
+ return (*slot)->discriminator;
+}
+
+/* Return TRUE if LOCUS1 and LOCUS2 refer to the same source line. */
+
+static bool
+same_line_p (location_t locus1, location_t locus2)
+{
+ expanded_location from, to;
+
+ if (locus1 == locus2)
+ return true;
+
+ from = expand_location (locus1);
+ to = expand_location (locus2);
+
+ if (from.line != to.line)
+ return false;
+ if (from.file == to.file)
+ return true;
+ return (from.file != NULL
+ && to.file != NULL
+ && strcmp (from.file, to.file) == 0);
+}
+
+/* Assign a unique discriminator value to block BB if it begins at the same
+ LOCUS as its predecessor block. */
+
+static void
+assign_discriminator (location_t locus, basic_block bb)
+{
+ gimple to_stmt;
+
+ if (locus == 0 || bb->discriminator != 0)
+ return;
+
+ to_stmt = first_non_label_stmt (bb);
+ if (to_stmt && same_line_p (locus, gimple_location (to_stmt)))
+ bb->discriminator = next_discriminator_for_locus (locus);
+}