[Libomptarget] Remove requires information from plugin

Summary:
Currently this is only used for the zero-copy handling. However, this
can easily be moved into `libomptarget` so that we do not need to bother
setting the requires flags in the plugin. The advantage here is that we
no longer need to do this for every device redundently. Additionally,
these requires flags are specifically OpenMP related, so they should
live in `libomptarget`.

Author: jhuber6

openmp/libomptarget/include/Shared/PluginAPI.h

@@ -45,9 +45,6 @@ int32_t __tgt_rtl_is_data_exchangable(int32_t SrcDevId, int32_t DstDevId);
 // functions)
 int32_t __tgt_rtl_supports_empty_images();
 
-// Initialize the requires flags for the device.
-int64_t __tgt_rtl_init_requires(int64_t RequiresFlags);
-
 // Initialize the specified device. In case of success return 0; otherwise
 // return an error code.
 int32_t __tgt_rtl_init_device(int32_t ID);

openmp/libomptarget/include/Shared/PluginAPI.inc

@@ -30,7 +30,6 @@ PLUGIN_API_HANDLE(data_exchange, false);
 PLUGIN_API_HANDLE(data_exchange_async, false);
 PLUGIN_API_HANDLE(data_delete, true);
 PLUGIN_API_HANDLE(launch_kernel, true);
-PLUGIN_API_HANDLE(init_requires, false);
 PLUGIN_API_HANDLE(synchronize, false);
 PLUGIN_API_HANDLE(query_async, false);
 PLUGIN_API_HANDLE(supports_empty_images, false);

openmp/libomptarget/plugins-nextgen/common/include/PluginInterface.h

@@ -1020,12 +1020,6 @@ struct GenericPluginTy {
     return *RPCServer;
   }
 
-  /// Get the OpenMP requires flags set for this plugin.
-  int64_t getRequiresFlags() const { return RequiresFlags; }
-
-  /// Set the OpenMP requires flags for this plugin.
-  void setRequiresFlag(int64_t Flags) { RequiresFlags = Flags; }
-
   /// Initialize a device within the plugin.
   Error initDevice(int32_t DeviceId);
 

openmp/libomptarget/plugins-nextgen/common/src/PluginInterface.cpp

@@ -852,6 +852,7 @@ Error GenericDeviceTy::deinit(GenericPluginTy &Plugin) {
 
   return deinitImpl();
 }
+
 Expected<DeviceImageTy *>
 GenericDeviceTy::loadBinary(GenericPluginTy &Plugin,
                             const __tgt_device_image *InputTgtImage) {
@@ -1637,11 +1638,6 @@ int32_t __tgt_rtl_init_device(int32_t DeviceId) {
 
 int32_t __tgt_rtl_number_of_devices() { return Plugin::get().getNumDevices(); }
 
-int64_t __tgt_rtl_init_requires(int64_t RequiresFlags) {
-  Plugin::get().setRequiresFlag(RequiresFlags);
-  return OFFLOAD_SUCCESS;
-}
-
 int32_t __tgt_rtl_is_data_exchangable(int32_t SrcDeviceId,
                                       int32_t DstDeviceId) {
   return Plugin::get().isDataExchangable(SrcDeviceId, DstDeviceId);
@@ -1989,8 +1985,6 @@ int32_t __tgt_rtl_use_auto_zero_copy(int32_t DeviceId) {
   // Automatic zero-copy only applies to programs that did
   // not request unified_shared_memory and are deployed on an
   // APU with XNACK enabled.
-  if (Plugin::get().getRequiresFlags() & OMP_REQ_UNIFIED_SHARED_MEMORY)
-    return false;
   return Plugin::get().getDevice(DeviceId).useAutoZeroCopy();
 }
 

openmp/libomptarget/src/device.cpp

@@ -77,17 +77,7 @@ DeviceTy::~DeviceTy() {
 }
 
 llvm::Error DeviceTy::init() {
-  // Make call to init_requires if it exists for this plugin.
-  int32_t Ret = 0;
-  if (RTL->init_requires)
-    Ret = RTL->init_requires(PM->getRequirements());
-  if (Ret != OFFLOAD_SUCCESS)
-    return llvm::createStringError(
-        llvm::inconvertibleErrorCode(),
-        "Failed to initialize requirements for device %d\n", DeviceID);
-
-  Ret = RTL->init_device(RTLDeviceID);
-  if (Ret != OFFLOAD_SUCCESS)
+  if (RTL->init_device(RTLDeviceID) != OFFLOAD_SUCCESS)
     return llvm::createStringError(llvm::inconvertibleErrorCode(),
                                    "Failed to initialize device %d\n",
                                    DeviceID);
@@ -310,6 +300,10 @@ void DeviceTy::dumpOffloadEntries() {
 }
 
 bool DeviceTy::useAutoZeroCopy() {
+  // Automatic zero-copy only applies when unfiied shared memory is disabled.
+  if (PM->getRequirements() & OMP_REQ_UNIFIED_SHARED_MEMORY)
+    return false;
+
   if (RTL->use_auto_zero_copy)
     return RTL->use_auto_zero_copy(RTLDeviceID);
   return false;