[Offload] Introduce dataFence plugin interface. (#153793)

The purpose of this fence is to ensure that any `dataSubmit`s inserted
into a queue before a `dataFence` finish before finish before any
`dataSubmit`s
inserted after it begin.

This is a no-op for most queues, since they are in-order, and by design
any operations inserted into them occur in order.

But the interface is supposed to be functional for out-of-order queues.

The addition of the interface means that any operations that rely on
such ordering (like ATTACH map-type support in #149036) can invoke it,
without worrying about whether the underlying queue is in-order or
out-of-order.

Once a plugin supports out-of-order queues, the plugin can implement
this function, without requiring any change at the libomptarget level.

---------

Co-authored-by: Alex Duran <alejandro.duran@intel.com>

1 files changed, 8 insertions, 0 deletions

diff --git a/offload/plugins-nextgen/common/include/PluginInterface.h b/offload/plugins-nextgen/common/include/PluginInterface.h
index 5e32a1a76d96..a448721755a6 100644
--- a/offload/plugins-nextgen/common/include/PluginInterface.h
+++ b/offload/plugins-nextgen/common/include/PluginInterface.h
@@ -944,6 +944,10 @@ struct GenericDeviceTy : public DeviceAllocatorTy {
   virtual Error dataRetrieveImpl(void *HstPtr, const void *TgtPtr, int64_t Size,
                                  AsyncInfoWrapperTy &AsyncInfoWrapper) = 0;
 
+  /// Instert a data fence between previous data operations and the following
+  /// operations if necessary for the device
+  virtual Error dataFence(__tgt_async_info *AsyncInfo) = 0;
+
   /// Exchange data between devices (device to device transfer). Calling this
   /// function is only valid if GenericPlugin::isDataExchangable() passing the
   /// two devices returns true.
@@ -1454,6 +1458,10 @@ public:
                               int DstDeviceId, void *DstPtr, int64_t Size,
                               __tgt_async_info *AsyncInfo);
 
+  /// Places a fence between previous data movements and following data
+  /// movements if necessary on the device
+  int32_t data_fence(int32_t DeviceId, __tgt_async_info *AsyncInfo);
+
   /// Begin executing a kernel on the given device.
   int32_t launch_kernel(int32_t DeviceId, void *TgtEntryPtr, void **TgtArgs,
                         ptrdiff_t *TgtOffsets, KernelArgsTy *KernelArgs,