Reland 10216 - Optimize the equality check case of ICCompare stubs.

src/ic.cc

 // Copyright 2011 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 2302 matching lines @@
   return static_cast<State>(target->compare_state());
 }
 
 
 const char* CompareIC::GetStateName(State state) {
   switch (state) {
     case UNINITIALIZED: return "UNINITIALIZED";
     case SMIS: return "SMIS";
     case HEAP_NUMBERS: return "HEAP_NUMBERS";
     case OBJECTS: return "OBJECTS";
+    case KNOWN_OBJECTS: return "OBJECTS";
     case SYMBOLS: return "SYMBOLS";
     case STRINGS: return "STRINGS";
     case GENERIC: return "GENERIC";
     default:
       UNREACHABLE();
       return NULL;
   }
 }
 
 
 CompareIC::State CompareIC::TargetState(State state,
                                         bool has_inlined_smi_code,
                                         Handle<Object> x,
                                         Handle<Object> y) {
-  if (!has_inlined_smi_code && state != UNINITIALIZED && state != SYMBOLS) {
-    return GENERIC;
+  switch (state) {
+    case UNINITIALIZED:
+      if (x->IsSmi() && y->IsSmi()) return SMIS;
+      if (x->IsNumber() && y->IsNumber()) return HEAP_NUMBERS;
+      if (!Token::IsEqualityOp(op_)) return GENERIC;
+      if (x->IsSymbol() && y->IsSymbol()) return SYMBOLS;
+      if (x->IsString() && y->IsString()) return STRINGS;
+      if (x->IsJSObject() && y->IsJSObject()) {
+        if (Handle<JSObject>::cast(x)->map() ==
+            Handle<JSObject>::cast(y)->map() &&
+            Token::IsEqualityOp(op_)) {
+          return KNOWN_OBJECTS;
+        } else {
+          return OBJECTS;
+        }
+      }
+      return GENERIC;
+    case SMIS:
+      return has_inlined_smi_code && x->IsNumber() && y->IsNumber()
+          ? HEAP_NUMBERS
+          : GENERIC;
+    case SYMBOLS:
+      ASSERT(Token::IsEqualityOp(op_));
+      return x->IsString() && y->IsString() ? STRINGS : GENERIC;
+    case HEAP_NUMBERS:
+    case STRINGS:
+    case OBJECTS:
+    case KNOWN_OBJECTS:
+    case GENERIC:
+      return GENERIC;
+    default:
+      UNREACHABLE();

[Kevin Millikin (Chromium), 2011/12/09 09:10:31]

I'd rather have this outside the switch:

switch (state) {
  case ...  // Cases for all enum values.
}
UNREACHABLE();
return NULL;

[Rico, 2011/12/09 09:28:31]

Done.

+      return NULL;
   }
-  if (state == UNINITIALIZED && x->IsSmi() && y->IsSmi()) return SMIS;
-  if ((state == UNINITIALIZED || (state == SMIS && has_inlined_smi_code)) &&
-      x->IsNumber() && y->IsNumber()) return HEAP_NUMBERS;
-  if (op_ != Token::EQ && op_ != Token::EQ_STRICT) return GENERIC;
-  if (state == UNINITIALIZED &&
-      x->IsSymbol() && y->IsSymbol()) return SYMBOLS;
-  if ((state == UNINITIALIZED || state == SYMBOLS) &&
-      x->IsString() && y->IsString()) return STRINGS;
-  if (state == UNINITIALIZED &&
-      x->IsJSObject() && y->IsJSObject()) return OBJECTS;
-  return GENERIC;
 }
 
 
 // Used from ic_<arch>.cc.
 RUNTIME_FUNCTION(Code*, CompareIC_Miss) {
   NoHandleAllocation na;
   ASSERT(args.length() == 3);
   CompareIC ic(isolate, static_cast<Token::Value>(args.smi_at(2)));
   ic.UpdateCaches(args.at<Object>(0), args.at<Object>(1));
   return ic.target();
@@ skipping 32 matching lines @@
 #undef ADDR
 };
 
 
 Address IC::AddressFromUtilityId(IC::UtilityId id) {
   return IC_utilities[id];
 }
 
 
 } }  // namespace v8::internal