X87: Fix keyed element access wrt string wrappers

src/x87/macro-assembler-x87.cc

Index: src/x87/macro-assembler-x87.cc
diff --git a/src/x87/macro-assembler-x87.cc b/src/x87/macro-assembler-x87.cc
index 3dc8b74a8115d4d2e707d5c03acc839a15b03a6f..b819424976d9de962e0a7fd04148af4067122f20 100644
--- a/src/x87/macro-assembler-x87.cc
+++ b/src/x87/macro-assembler-x87.cc
@@ -3055,14 +3055,22 @@ void MacroAssembler::JumpIfDictionaryInPrototypeChain(
   DCHECK(!scratch1.is(scratch0));
   Factory* factory = isolate()->factory();
   Register current = scratch0;
-  Label loop_again;
+  Label loop_again, end;
 
   // scratch contained elements pointer.
   mov(current, object);
+  mov(current, FieldOperand(current, HeapObject::kMapOffset));
+  mov(current, FieldOperand(current, Map::kPrototypeOffset));
+  cmp(current, Immediate(factory->null_value()));
+  j(equal, &end);
 
   // Loop based on the map going up the prototype chain.
   bind(&loop_again);
   mov(current, FieldOperand(current, HeapObject::kMapOffset));
+  STATIC_ASSERT(JS_PROXY_TYPE < JS_OBJECT_TYPE);
+  STATIC_ASSERT(JS_VALUE_TYPE < JS_OBJECT_TYPE);
+  CmpInstanceType(current, JS_OBJECT_TYPE);
+  j(below, found);
   mov(scratch1, FieldOperand(current, Map::kBitField2Offset));
   DecodeField<Map::ElementsKindBits>(scratch1);
   cmp(scratch1, Immediate(DICTIONARY_ELEMENTS));
@@ -3070,6 +3078,8 @@ void MacroAssembler::JumpIfDictionaryInPrototypeChain(
   mov(current, FieldOperand(current, Map::kPrototypeOffset));
   cmp(current, Immediate(factory->null_value()));
   j(not_equal, &loop_again);
+
+  bind(&end);
 }