Implement monitorenter/monitorexit.

Pretty simple as they just invoke the runtime.

Change-Id: I5fcb2c783deac27e55e28d8b3da3e68ea4b77363
diff --git a/compiler/optimizing/code_generator_x86.cc b/compiler/optimizing/code_generator_x86.cc
index 14c7fe4..bed44b2 100644
--- a/compiler/optimizing/code_generator_x86.cc
+++ b/compiler/optimizing/code_generator_x86.cc
@@ -2905,5 +2905,19 @@
   __ Bind(slow_path->GetExitLabel());
 }
 
+void LocationsBuilderX86::VisitMonitorOperation(HMonitorOperation* instruction) {
+  LocationSummary* locations =
+      new (GetGraph()->GetArena()) LocationSummary(instruction, LocationSummary::kCall);
+  InvokeRuntimeCallingConvention calling_convention;
+  locations->SetInAt(0, Location::RegisterLocation(calling_convention.GetRegisterAt(0)));
+}
+
+void InstructionCodeGeneratorX86::VisitMonitorOperation(HMonitorOperation* instruction) {
+  __ fs()->call(Address::Absolute(instruction->IsEnter()
+        ? QUICK_ENTRYPOINT_OFFSET(kX86WordSize, pLockObject)
+        : QUICK_ENTRYPOINT_OFFSET(kX86WordSize, pUnlockObject)));
+  codegen_->RecordPcInfo(instruction, instruction->GetDexPc());
+}
+
 }  // namespace x86
 }  // namespace art