AOT: Add a separate switchable call state for unlinked calls.

runtime/vm/stub_code_arm.cc

Index: runtime/vm/stub_code_arm.cc
diff --git a/runtime/vm/stub_code_arm.cc b/runtime/vm/stub_code_arm.cc
index 82c50a1efc8063ec95d161602081438133cfa4cc..c94edc5249fa79ae805a431735a3ddf0870948e8 100644
--- a/runtime/vm/stub_code_arm.cc
+++ b/runtime/vm/stub_code_arm.cc
@@ -2125,6 +2125,31 @@ void StubCode::GenerateICCallThroughCodeStub(Assembler* assembler) {
 
 // Called from switchable IC calls.
 //  R0: receiver
+//  R9: UnlinkedCall
+void StubCode::GenerateUnlinkedCallStub(Assembler* assembler) {
+  __ NoMonomorphicCheckedEntry();
+
+  __ EnterStubFrame();
+  __ Push(R0);  // Preserve receiver.
+
+  __ PushObject(Object::null_object());  // Result.

[Florian Schneider, 2016/09/23 17:57:59]

Would it be worth filling the result slot with smi-zero instead of object null?

[rmacnak, 2016/09/26 17:32:53]

Maybe. I'll create another CL that makes that change for all the runtime calls.

+  __ Push(R0);                           // Arg0: Receiver
+  __ Push(R9);                           // Arg1: UnlinkedCall
+  __ CallRuntime(kUnlinkedCallRuntimeEntry, 2);
+  __ Drop(2);
+  __ Pop(R9);  // result = IC
+
+  __ Pop(R0);  // Restore receiver.
+  __ LeaveStubFrame();
+
+  __ ldr(CODE_REG, Address(THR, Thread::ic_lookup_through_code_stub_offset()));
+  __ ldr(R1, FieldAddress(CODE_REG, Code::checked_entry_point_offset()));
+  __ bx(R1);
+}
+
+
+// Called from switchable IC calls.
+//  R0: receiver
 //  R9: SingleTargetCache
 // Passed to target:
 //  CODE_REG: target Code object