[PairPos] Cache coverage as well

Another 3% down in Roboto-Regular.

src/OT/Layout/Common/Coverage.hh

@@ -96,6 +96,15 @@ struct Coverage
     default:return NOT_COVERED;
     }
   }
+  unsigned int get_coverage (hb_codepoint_t glyph_id,
+			     hb_ot_lookup_cache_t *cache) const
+  {
+    unsigned coverage;
+    if (cache && cache->get (glyph_id, &coverage)) return coverage;
+    coverage = get_coverage (glyph_id);
+    if (cache) cache->set (glyph_id, coverage);
+    return coverage;
+  }
 
   unsigned get_population () const
   {
@@ -201,6 +210,19 @@ struct Coverage
     }
   }
 
+  unsigned cost () const
+  {
+    switch (u.format) {
+    case 1: hb_barrier (); return u.format1.cost ();
+    case 2: hb_barrier (); return u.format2.cost ();
+#ifndef HB_NO_BEYOND_64K
+    case 3: hb_barrier (); return u.format3.cost ();
+    case 4: hb_barrier (); return u.format4.cost ();
+#endif
+    default:return 0u;
+    }
+  }
+
   /* Might return false if array looks unsorted.
    * Used for faster rejection of corrupt data. */
   template <typename set_t>

src/OT/Layout/Common/CoverageFormat1.hh

@@ -103,6 +103,8 @@ struct CoverageFormat1_3
         intersect_glyphs << glyphArray[i];
   }
 
+  unsigned cost () const { return 1; }
+
   template <typename set_t>
   bool collect_coverage (set_t *glyphs) const
   { return glyphs->add_sorted_array (glyphArray.as_array ()); }

src/OT/Layout/Common/CoverageFormat2.hh

@@ -157,6 +157,8 @@ struct CoverageFormat2_4
     }
   }
 
+  unsigned cost () const { return hb_bit_storage ((unsigned) rangeRecord.len); /* bsearch cost */ }
+
   template <typename set_t>
   bool collect_coverage (set_t *glyphs) const
   {

src/OT/Layout/GPOS/PairPosFormat2.hh

@@ -123,12 +123,16 @@ struct PairPosFormat2_4 : ValueBase
 
   const Coverage &get_coverage () const { return this+coverage; }
 
-  using pair_pos_cache_t = hb_pair_t<hb_ot_class_cache_t, hb_ot_class_cache_t>;
+  struct pair_pos_cache_t
+  {
+    hb_ot_lookup_cache_t coverage;
+    hb_ot_lookup_cache_t first;
+    hb_ot_lookup_cache_t second;
+  };
 
   unsigned cache_cost () const
   {
-    unsigned c = (this+classDef1).cost () + (this+classDef2).cost ();
-    return c >= 4 ? c : 0;
+    return (this+coverage).cost () + (this+classDef1).cost () + (this+classDef2).cost ();
   }
   static void * cache_func (void *p, hb_ot_lookup_cache_op_t op)
   {
@@ -139,6 +143,7 @@ struct PairPosFormat2_4 : ValueBase
 	pair_pos_cache_t *cache = (pair_pos_cache_t *) hb_malloc (sizeof (pair_pos_cache_t));
 	if (likely (cache))
 	{
+	  cache->coverage.clear ();
 	  cache->first.clear ();
 	  cache->second.clear ();
 	}
@@ -162,8 +167,17 @@ struct PairPosFormat2_4 : ValueBase
   bool _apply (hb_ot_apply_context_t *c, bool cached) const
   {
     TRACE_APPLY (this);
+
+#ifndef HB_NO_OT_LAYOUT_LOOKUP_CACHE
+    pair_pos_cache_t *cache = cached ? (pair_pos_cache_t *) c->lookup_accel->cache : nullptr;
+#endif
+
     hb_buffer_t *buffer = c->buffer;
+#ifndef HB_NO_OT_LAYOUT_LOOKUP_CACHE
+    unsigned int index = (this+coverage).get_coverage  (buffer->cur().codepoint, cache ? &cache->coverage : nullptr);
+#else
     unsigned int index = (this+coverage).get_coverage  (buffer->cur().codepoint);
+#endif
     if (likely (index == NOT_COVERED)) return_trace (false);
 
     hb_ot_apply_context_t::skipping_iterator_t &skippy_iter = c->iter_input;
@@ -176,7 +190,6 @@ struct PairPosFormat2_4 : ValueBase
     }
 
 #ifndef HB_NO_OT_LAYOUT_LOOKUP_CACHE
-    pair_pos_cache_t *cache = cached ? (pair_pos_cache_t *) c->lookup_accel->cache : nullptr;
     unsigned int klass1 = (this+classDef1).get_class (buffer->cur().codepoint, cache ? &cache->first : nullptr);
     unsigned int klass2 = (this+classDef2).get_class (buffer->info[skippy_iter.idx].codepoint, cache ? &cache->second : nullptr);
 #else

src/OT/Layout/types.hh

@@ -29,6 +29,9 @@
 #ifndef OT_LAYOUT_TYPES_HH
 #define OT_LAYOUT_TYPES_HH
 
+using hb_ot_lookup_cache_t = hb_cache_t<15, 8, 7>;
+static_assert (sizeof (hb_ot_lookup_cache_t) == 256, "");
+
 namespace OT {
 namespace Layout {
 

src/hb-ot-layout-common.hh

@@ -48,9 +48,6 @@ using OT::Layout::MediumTypes;
 
 namespace OT {
 
-using hb_ot_class_cache_t = hb_cache_t<15, 8, 7>;
-static_assert (sizeof (hb_ot_class_cache_t) == 256, "");
-
 template<typename Iterator>
 static inline bool ClassDef_serialize (hb_serialize_context_t *c,
 				       Iterator it);
@@ -2081,7 +2078,7 @@ struct ClassDef
     }
   }
   unsigned int get_class (hb_codepoint_t glyph_id,
-			  hb_ot_class_cache_t *cache) const
+			  hb_ot_lookup_cache_t *cache) const
   {
     unsigned klass;
     if (cache && cache->get (glyph_id, &klass)) return klass;