Fix keyed element access wrt string wrappers

src/ic/mips/ic-mips.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_MIPS
 
 #include "src/codegen.h"
@@ skipping 638 matching lines @@
   __ lw(receiver_map, FieldMemOperand(receiver, HeapObject::kMapOffset));
   // Check that the receiver does not require access checks and is not observed.
   // The generic stub does not perform map checks or handle observed objects.
   __ lbu(t0, FieldMemOperand(receiver_map, Map::kBitFieldOffset));
   __ And(t0, t0,
          Operand(1 << Map::kIsAccessCheckNeeded | 1 << Map::kIsObserved));
   __ Branch(&slow, ne, t0, Operand(zero_reg));
   // Check if the object is a JS array or not.
   __ lbu(t0, FieldMemOperand(receiver_map, Map::kInstanceTypeOffset));
   __ Branch(&array, eq, t0, Operand(JS_ARRAY_TYPE));
-  // Check that the object is some kind of JSObject.
-  __ Branch(&slow, lt, t0, Operand(FIRST_JS_OBJECT_TYPE));
+  // Check that the object is some kind of JS object EXCEPT JS Value type. In
+  // the case that the object is a value-wrapper object, we enter the runtime
+  // system to make sure that indexing into string objects works as intended.
+  STATIC_ASSERT(JS_VALUE_TYPE < JS_OBJECT_TYPE);
+  __ Branch(&slow, lo, t0, Operand(JS_OBJECT_TYPE));
 
   // Object case: Check key against length in the elements array.
   __ lw(elements, FieldMemOperand(receiver, JSObject::kElementsOffset));
   // Check array bounds. Both the key and the length of FixedArray are smis.
   __ lw(t0, FieldMemOperand(elements, FixedArray::kLengthOffset));
   __ Branch(&fast_object, lo, key, Operand(t0));
 
   // Slow case, handle jump to runtime.
   __ bind(&slow);
   // Entry registers are intact.
@@ skipping 226 matching lines @@
     patcher.ChangeBranchCondition(ne);
   } else {
     DCHECK(Assembler::IsBne(branch_instr));
     patcher.ChangeBranchCondition(eq);
   }
 }
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_TARGET_ARCH_MIPS