The IC exposes a register definition.

src/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
 
@@ skipping 542 matching lines @@
   __ Push(a1, a0);
 
   // Perform tail call to the entry.
   ExternalReference ref =
       ExternalReference(IC_Utility(kKeyedLoadIC_Miss), isolate);
 
   __ TailCallExternalReference(ref, 2, 1);
 }
 
 
+// IC register specifications
+const Register LoadIC::ReceiverRegister() { return a0; }
+const Register LoadIC::NameRegister() { return a2; }
+const Register KeyedLoadIC::ReceiverRegister() { return a1; }
+const Register KeyedLoadIC::NameRegister() { return a0; }
+
+
+const Register* KeyedLoadIC::AllocateRegisterArray() {
+  Register* registers = new Register[kRegisterArgumentCount];
+  registers[0] = ReceiverRegister();
+  registers[1] = NameRegister();
+  return registers;
+}
+
+
 void KeyedLoadIC::GenerateRuntimeGetProperty(MacroAssembler* masm) {
   // ---------- S t a t e --------------
   //  -- ra     : return address
   //  -- a0     : key
   //  -- a1     : receiver
   // -----------------------------------
 
   __ Push(a1, a0);
 
   __ TailCallRuntime(Runtime::kKeyedGetProperty, 2, 1);
@@ skipping 758 matching lines @@
   } else {
     ASSERT(Assembler::IsBne(branch_instr));
     patcher.ChangeBranchCondition(eq);
   }
 }
 
 
 } }  // namespace v8::internal
 
 #endif  // V8_TARGET_ARCH_MIPS