Reland 21774: Generate KeyedLoadGeneric with Hydrogen

src/heap.cc

Index: src/heap.cc
diff --git a/src/heap.cc b/src/heap.cc
index d5c40ad154ad0e8de49a1ba86de2a659c352dbb7..b46ddfa89f4d9e4905dd5c21af60ff3f739dc2f5 100644
--- a/src/heap.cc
+++ b/src/heap.cc
@@ -7709,12 +7709,34 @@ int KeyedLookupCache::Hash(Map* map, Name* name) {
 }
 
 
+int KeyedLookupCache::ConvertToFastIndexForGeneratedCode(Map* map, int index) {
+  if (FLAG_compiled_keyed_generic_loads) {
+    if (index >= map->inobject_properties()) {
+      return -(index - map->inobject_properties() + 1);

[Toon Verwaest, 2013/12/04 17:29:26]

Seems like this should be combined with the code in
PropertyIndex::translate/is_inobject. (Why is the index here and int rather than
a PropertyIndex object?)

[danno, 2014/06/06 15:43:50]

Well, essentially because they are are not the same as the index returned from
PropertyIndex.translate(), which returns negative values for in object
properties and positive values for out-of-object. Here, we need exactly the
opposite to work out-of-the-box with HLoadIndexField, which doesn't have a map
for the size of the object and therefore can use negative values to do the math
from the end of the object dynamically.

+    }
+  }
+  return index;
+}
+
+
+int KeyedLookupCache::ConvertFromFastIndexForGeneratedCode(Map* map,
+                                                           int index) {
+  if (FLAG_compiled_keyed_generic_loads) {
+    if (index < 0) {
+      return -index + map->inobject_properties() - 1;

[Toon Verwaest, 2013/12/04 17:29:26]

Same as above.

[danno, 2014/06/06 15:43:50]

See my comment above.

+    }
+  }
+  return index;
+}
+
+
 int KeyedLookupCache::Lookup(Map* map, Name* name) {
   int index = (Hash(map, name) & kHashMask);
   for (int i = 0; i < kEntriesPerBucket; i++) {
     Key& key = keys_[index + i];
     if ((key.map == map) && key.name->Equals(name)) {
-      return field_offsets_[index + i];
+      int result = field_offsets_[index + i];
+      result = ConvertFromFastIndexForGeneratedCode(map, result);
     }
   }
   return kNotFound;
@@ -7734,6 +7756,11 @@ void KeyedLookupCache::Update(Map* map, Name* name, int field_offset) {
   // cache to only contain old space names.
   ASSERT(!map->GetIsolate()->heap()->InNewSpace(name));
 
+  // Swizzle the field offset so that it's in the most efficient format to be
+  // accessed in the cache from generated code: in-object properties are index
+  // offsets and out-of-object are negative offsets.
+  field_offset = ConvertToFastIndexForGeneratedCode(map, field_offset);
+
   int index = (Hash(map, name) & kHashMask);
   // After a GC there will be free slots, so we use them in order (this may
   // help to get the most frequently used one in position 0).