Track representations of fields

src/arm/stub-cache-arm.cc

Index: src/arm/stub-cache-arm.cc
diff --git a/src/arm/stub-cache-arm.cc b/src/arm/stub-cache-arm.cc
index f22acb4709e386d75a2a4df18f981624449de2fa..e3e5aa2022ec10b1f8d6a4874712e5aaa939b31b 100644
--- a/src/arm/stub-cache-arm.cc
+++ b/src/arm/stub-cache-arm.cc
@@ -2897,6 +2897,7 @@ Handle<Code> LoadStubCompiler::CompileLoadGlobal(
 Handle<Code> BaseLoadStubCompiler::CompilePolymorphicIC(
     MapHandleList* receiver_maps,
     CodeHandleList* handlers,
+    int number_of_valid_maps,
     Handle<Name> name,
     Code::StubType type,
     IcCheckType check) {
@@ -2912,17 +2913,19 @@ Handle<Code> BaseLoadStubCompiler::CompilePolymorphicIC(
   int receiver_count = receiver_maps->length();
   __ ldr(map_reg, FieldMemOperand(receiver(), HeapObject::kMapOffset));
   for (int current = 0; current < receiver_count; ++current) {
-    __ mov(ip, Operand(receiver_maps->at(current)));
-    __ cmp(map_reg, ip);
-    __ Jump(handlers->at(current), RelocInfo::CODE_TARGET, eq);
+    Handle<Map> map = receiver_maps->at(current);
+    if (!map->is_invalid_transition()) {

[danno, 2013/04/24 15:23:00]

how about reversing the sense of the predicate to is_valid to make reading this
easier? Or add a second version in addition to the is_invalid?

+      __ mov(ip, Operand(receiver_maps->at(current)));
+      __ cmp(map_reg, ip);
+      __ Jump(handlers->at(current), RelocInfo::CODE_TARGET, eq);
+    }
   }
 
   __ bind(&miss);
   TailCallBuiltin(masm(), MissBuiltin(kind()));
 
   // Return the generated code.
-  InlineCacheState state =
-      receiver_maps->length() > 1 ? POLYMORPHIC : MONOMORPHIC;
+  InlineCacheState state = number_of_valid_maps > 1 ? POLYMORPHIC : MONOMORPHIC;
   return GetICCode(kind(), type, name, state);
 }