MIPS: Fix for instanceof-proxies failure.

src/mips/code-stubs-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.
 
 #if V8_TARGET_ARCH_MIPS
 
 #include "src/base/bits.h"
 #include "src/bootstrapper.h"
 #include "src/code-stubs.h"
 #include "src/codegen.h"
@@ skipping 1511 matching lines @@
         FieldMemOperand(object, HeapObject::kMapOffset));  // In delay slot.
   __ LoadRoot(result, Heap::kFalseValueRootIndex);
   __ bind(&done);
   __ Ret(USE_DELAY_SLOT);
   __ StoreRoot(result,
                Heap::kInstanceofCacheAnswerRootIndex);  // In delay slot.
 
   // Proxy-case: Call the %HasInPrototypeChain runtime function.
   __ bind(&proxy_case);
   __ Push(object, function_prototype);
+  // Invalidate the instanceof cache.
+  __ li(scratch, Operand(Smi::FromInt(0)));

[dusan.milosavljevic, 2015/12/12 02:40:25]

Can we use zero reg here?

[paul.l..., 2015/12/12 02:55:27]

Definitely we could use move from zero reg. But li() will be encoded as
addiu(scratch, zero_reg, 0), which is single instruction, and unlikely to take
any longer to execute (no memory refs). (With the mov() version, I'd feel
obligated to add an Assert that Smi::FromInt(0) is really zero:) Anyway, I don't
see a payoff for the mov(), do you?

[paul.l..., 2015/12/12 02:57:11]

Sorry, you are right, I missed it. I think I stopped the commit, I'll update the
CL.

+  __ StoreRoot(scratch, Heap::kInstanceofCacheFunctionRootIndex);
   __ TailCallRuntime(Runtime::kHasInPrototypeChain, 2, 1);
 
   // Slow-case: Call the %InstanceOf runtime function.
   __ bind(&slow_case);
   __ Push(object, function);
   __ TailCallRuntime(Runtime::kInstanceOf, 2, 1);
 }
 
 
 void FunctionPrototypeStub::Generate(MacroAssembler* masm) {
@@ skipping 4023 matching lines @@
                            MemOperand(fp, 6 * kPointerSize), NULL);
 }
 
 
 #undef __
 
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_TARGET_ARCH_MIPS