X87: Fix keyed element access wrt string wrappers

src/x87/macro-assembler-x87.cc

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "src/v8.h"
 
 #if V8_TARGET_ARCH_X87
 
 #include "src/base/bits.h"
 #include "src/base/division-by-constant.h"
@@ skipping 3037 matching lines @@
 
 
 void MacroAssembler::JumpIfDictionaryInPrototypeChain(
     Register object,
     Register scratch0,
     Register scratch1,
     Label* found) {
   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));
   j(equal, found);
   mov(current, FieldOperand(current, Map::kPrototypeOffset));
   cmp(current, Immediate(factory->null_value()));
   j(not_equal, &loop_again);
+
+  bind(&end);
 }
 
 
 void MacroAssembler::TruncatingDiv(Register dividend, int32_t divisor) {
   DCHECK(!dividend.is(eax));
   DCHECK(!dividend.is(edx));
   base::MagicNumbersForDivision<uint32_t> mag =
       base::SignedDivisionByConstant(static_cast<uint32_t>(divisor));
   mov(eax, Immediate(mag.multiplier));
   imul(dividend);
   bool neg = (mag.multiplier & (static_cast<uint32_t>(1) << 31)) != 0;
   if (divisor > 0 && neg) add(edx, dividend);
   if (divisor < 0 && !neg && mag.multiplier > 0) sub(edx, dividend);
   if (mag.shift > 0) sar(edx, mag.shift);
   mov(eax, dividend);
   shr(eax, 31);
   add(edx, eax);
 }
 
 
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_TARGET_ARCH_X87