S390: InstanceOfStub incorrectly interprets the hole as a prototype.

src/s390/code-stubs-s390.cc

 // Copyright 2014 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.
 
 #if V8_TARGET_ARCH_S390
 
 #include "src/code-stubs.h"
 #include "src/api-arguments.h"
 #include "src/base/bits.h"
 #include "src/bootstrapper.h"
@@ skipping 1396 matching lines @@
   __ bne(&slow_case);
   __ LoadRoot(r2, Heap::kFalseValueRootIndex);
   __ Ret();
 
   // Fast-case: The {function} must be a valid JSFunction.
   __ bind(&fast_case);
   __ JumpIfSmi(function, &slow_case);
   __ CompareObjectType(function, function_map, scratch, JS_FUNCTION_TYPE);
   __ bne(&slow_case);
 
+  // Go to the runtime if the function is not a constructor.
+  __ LoadlB(scratch, FieldMemOperand(function_map, Map::kBitFieldOffset));
+  __ TestBit(scratch, Map::kIsConstructor, r0);
+  __ beq(&slow_case);
+
   // Ensure that {function} has an instance prototype.
-  __ LoadlB(scratch, FieldMemOperand(function_map, Map::kBitFieldOffset));
   __ TestBit(scratch, Map::kHasNonInstancePrototype, r0);
   __ bne(&slow_case);
 
   // Get the "prototype" (or initial map) of the {function}.
   __ LoadP(function_prototype,
            FieldMemOperand(function, JSFunction::kPrototypeOrInitialMapOffset));
   __ AssertNotSmi(function_prototype);
 
   // Resolve the prototype if the {function} has an initial map.  Afterwards the
   // {function_prototype} will be either the JSReceiver prototype object or the
@@ skipping 4281 matching lines @@
   CallApiFunctionAndReturn(masm, api_function_address, thunk_ref,
                            kStackUnwindSpace, NULL, return_value_operand, NULL);
 }
 
 #undef __
 
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_TARGET_ARCH_S390