diff --git a/openmp/libomptarget/src/api.cpp b/openmp/libomptarget/src/api.cpp
--- a/openmp/libomptarget/src/api.cpp
+++ b/openmp/libomptarget/src/api.cpp
@@ -57,8 +57,7 @@
     return NULL;
   }
 
-  DeviceTy &Device = Devices[device_num];
-  rc = Device.RTL->data_alloc(Device.RTLDeviceID, size, NULL);
+  rc = Devices[device_num].data_alloc(size);
   DP("omp_target_alloc returns device ptr " DPxMOD "\n", DPxPTR(rc));
   return rc;
 }
@@ -83,8 +82,7 @@
     return;
   }
 
-  DeviceTy &Device = Devices[device_num];
-  Device.RTL->data_delete(Device.RTLDeviceID, (void *)device_ptr);
+  Devices[device_num].data_delete(device_ptr);
   DP("omp_target_free deallocated device ptr\n");
 }
 
diff --git a/openmp/libomptarget/src/device.h b/openmp/libomptarget/src/device.h
--- a/openmp/libomptarget/src/device.h
+++ b/openmp/libomptarget/src/device.h
@@ -192,6 +192,18 @@
   int32_t initOnce();
   __tgt_target_table *load_binary(void *Img);
 
+  // device memory allocation/deallocation routines
+  /// Allocates \p Size bytes on the device and returns the address/nullptr when
+  /// succeeds/fails. \p HstPtr is an address of the host data which the
+  /// allocated target data will be associated with. If it is unknown, the
+  /// default value of \p HstPtr is nullptr. Note: this function doesn't do
+  /// pointer association. Actually, all the __tgt_rtl_data_alloc
+  /// implementations ignore \p HstPtr.
+  void *data_alloc(int64_t Size, void *HstPtr = nullptr);
+  /// Deallocates memory which \p TgtPtrBegin points at and returns
+  /// OFFLOAD_SUCCESS/OFFLOAD_FAIL when succeeds/fails.
+  int32_t data_delete(void *TgtPtrBegin);
+
   // Data transfer. When AsyncInfoPtr is nullptr, the transfer will be
   // synchronous.
   // Copy data from host to device
@@ -213,6 +225,10 @@
                           uint64_t LoopTripCount,
                           __tgt_async_info *AsyncInfoPtr);
 
+  /// Synchronize device/queue/event based on \p AsyncInfoPtr and return
+  /// OFFLOAD_SUCCESS/OFFLOAD_FAIL when succeeds/fails.
+  int32_t synchronize(__tgt_async_info *AsyncInfoPtr);
+
 private:
   // Call to RTL
   void init(); // To be called only via DeviceTy::initOnce()
diff --git a/openmp/libomptarget/src/device.cpp b/openmp/libomptarget/src/device.cpp
--- a/openmp/libomptarget/src/device.cpp
+++ b/openmp/libomptarget/src/device.cpp
@@ -217,7 +217,7 @@
   } else if (Size) {
     // If it is not contained and Size > 0, we should create a new entry for it.
     IsNew = true;
-    uintptr_t tp = (uintptr_t)RTL->data_alloc(RTLDeviceID, Size, HstPtrBegin);
+    uintptr_t tp = (uintptr_t)data_alloc(Size, HstPtrBegin);
     DP("Creating new map entry: HstBase=" DPxMOD ", HstBegin=" DPxMOD ", "
        "HstEnd=" DPxMOD ", TgtBegin=" DPxMOD "\n",
        DPxPTR(HstPtrBase), DPxPTR(HstPtrBegin),
@@ -299,7 +299,7 @@
     if (HT.decRefCount() == 0) {
       DP("Deleting tgt data " DPxMOD " of size %ld\n",
           DPxPTR(HT.TgtPtrBegin), Size);
-      RTL->data_delete(RTLDeviceID, (void *)HT.TgtPtrBegin);
+      data_delete((void *)HT.TgtPtrBegin);
       DP("Removing%s mapping with HstPtrBegin=" DPxMOD ", TgtPtrBegin=" DPxMOD
           ", Size=%ld\n", (ForceDelete ? " (forced)" : ""),
           DPxPTR(HT.HstPtrBegin), DPxPTR(HT.TgtPtrBegin), Size);
@@ -351,6 +351,14 @@
   return rc;
 }
 
+void *DeviceTy::data_alloc(int64_t Size, void *HstPtr) {
+  return RTL->data_alloc(RTLDeviceID, Size, HstPtr);
+}
+
+int32_t DeviceTy::data_delete(void *TgtPtrBegin) {
+  return RTL->data_delete(RTLDeviceID, TgtPtrBegin);
+}
+
 // Submit data to device
 int32_t DeviceTy::data_submit(void *TgtPtrBegin, void *HstPtrBegin,
                               int64_t Size, __tgt_async_info *AsyncInfoPtr) {
@@ -423,6 +431,12 @@
   return false;
 }
 
+int32_t DeviceTy::synchronize(__tgt_async_info *AsyncInfoPtr) {
+  if (RTL->synchronize)
+    return RTL->synchronize(RTLDeviceID, AsyncInfoPtr);
+  return OFFLOAD_SUCCESS;
+}
+
 /// Check whether a device has an associated RTL and initialize it if it's not
 /// already initialized.
 bool device_is_ready(int device_num) {
diff --git a/openmp/libomptarget/src/omptarget.cpp b/openmp/libomptarget/src/omptarget.cpp
--- a/openmp/libomptarget/src/omptarget.cpp
+++ b/openmp/libomptarget/src/omptarget.cpp
@@ -845,8 +845,7 @@
       TgtBaseOffset = 0;
     } else if (arg_types[i] & OMP_TGT_MAPTYPE_PRIVATE) {
       // Allocate memory for (first-)private array
-      TgtPtrBegin = Device.RTL->data_alloc(Device.RTLDeviceID,
-          arg_sizes[i], HstPtrBegin);
+      TgtPtrBegin = Device.data_alloc(arg_sizes[i], HstPtrBegin);
       if (!TgtPtrBegin) {
         DP ("Data allocation for %sprivate array " DPxMOD " failed, "
             "abort target.\n",
@@ -929,7 +928,7 @@
 
   // Deallocate (first-)private arrays
   for (auto it : fpArrays) {
-    int rt = Device.RTL->data_delete(Device.RTLDeviceID, it);
+    int rt = Device.data_delete(it);
     if (rt != OFFLOAD_SUCCESS) {
       DP("Deallocation of (first-)private arrays failed.\n");
       return OFFLOAD_FAIL;
@@ -944,8 +943,5 @@
     return OFFLOAD_FAIL;
   }
 
-  if (Device.RTL->synchronize)
-    return Device.RTL->synchronize(device_id, &AsyncInfo);
-
-  return OFFLOAD_SUCCESS;
+  return Device.synchronize(&AsyncInfo);
 }
diff --git a/openmp/libomptarget/src/rtl.h b/openmp/libomptarget/src/rtl.h
--- a/openmp/libomptarget/src/rtl.h
+++ b/openmp/libomptarget/src/rtl.h
@@ -52,7 +52,7 @@
                                             int32_t, uint64_t,
                                             __tgt_async_info *);
   typedef int64_t(init_requires_ty)(int64_t);
-  typedef int64_t(synchronize_ty)(int64_t, __tgt_async_info *);
+  typedef int64_t(synchronize_ty)(int32_t, __tgt_async_info *);
 
   int32_t Idx = -1;             // RTL index, index is the number of devices
                                 // of other RTLs that were registered before,