The IC exposes a register definition.

src/arm64/ic-arm64.cc

 // Copyright 2013 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_ARM64
 
 #include "src/arm64/assembler-arm64.h"
 #include "src/code-stubs.h"
@@ skipping 564 matching lines @@
   __ Push(x1, x0);
 
   // 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 x0; }
+const Register LoadIC::NameRegister() { return x2; }
+const Register KeyedLoadIC::ReceiverRegister() { return x1; }
+const Register KeyedLoadIC::NameRegister() { return x0; }
+
+
+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 --------------
   //  -- lr     : return address
   //  -- x0     : key
   //  -- x1     : receiver
   // -----------------------------------
   Register key = x0;
   Register receiver = x1;
 
   __ Push(receiver, key);
@@ skipping 783 matching lines @@
     ASSERT(to_patch->Mask(TestBranchMask) == TBNZ);
     // This is JumpIfSmi(smi_reg, branch_imm).
     patcher.tbz(smi_reg, 0, branch_imm);
   }
 }
 
 
 } }  // namespace v8::internal
 
 #endif  // V8_TARGET_ARCH_ARM64