The IC exposes a register definition.

src/arm64/ic-arm64.cc

Index: src/arm64/ic-arm64.cc
diff --git a/src/arm64/ic-arm64.cc b/src/arm64/ic-arm64.cc
index 842b3e75dcbf65d805bbbe3f6af2086e5b7aff01..d46cfb07732e1618642113ae737e376bc087ae6b 100644
--- a/src/arm64/ic-arm64.cc
+++ b/src/arm64/ic-arm64.cc
@@ -582,6 +582,21 @@ void KeyedLoadIC::GenerateMiss(MacroAssembler* masm) {
 }
 
 
+// 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