[Openmp-commits] [openmp] [Libomptarget] Remove requires information from plugin (PR #80345)

[Joseph Huber via Openmp-commits]

https://github.com/jhuber6 created https://github.com/llvm/llvm-project/pull/80345

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`.


>From b25924893185f8452e3380afc9b60bee3a516468 Mon Sep 17 00:00:00 2001
From: Joseph Huber <huberjn at outlook.com>
Date: Thu, 1 Feb 2024 15:38:17 -0600
Subject: [PATCH] [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`.
---
 openmp/libomptarget/include/Shared/PluginAPI.h   |  3 ---
 openmp/libomptarget/include/Shared/PluginAPI.inc |  1 -
 .../common/include/PluginInterface.h             |  6 ------
 .../common/src/PluginInterface.cpp               |  8 +-------
 openmp/libomptarget/src/device.cpp               | 16 +++++-----------
 5 files changed, 6 insertions(+), 28 deletions(-)

diff --git a/openmp/libomptarget/include/Shared/PluginAPI.h b/openmp/libomptarget/include/Shared/PluginAPI.h
index 5de5f106045b5..7d0fd8d029bff 100644
--- a/openmp/libomptarget/include/Shared/PluginAPI.h
+++ b/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);
diff --git a/openmp/libomptarget/include/Shared/PluginAPI.inc b/openmp/libomptarget/include/Shared/PluginAPI.inc
index 5f8a9dd11fdce..53102f4c3b3d1 100644
--- a/openmp/libomptarget/include/Shared/PluginAPI.inc
+++ b/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);
diff --git a/openmp/libomptarget/plugins-nextgen/common/include/PluginInterface.h b/openmp/libomptarget/plugins-nextgen/common/include/PluginInterface.h
index 3c2a4d7e6c0e7..d000ddcffb70a 100644
--- a/openmp/libomptarget/plugins-nextgen/common/include/PluginInterface.h
+++ b/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);
 
diff --git a/openmp/libomptarget/plugins-nextgen/common/src/PluginInterface.cpp b/openmp/libomptarget/plugins-nextgen/common/src/PluginInterface.cpp
index def9c14fa53f8..c34d504dc7ef5 100644
--- a/openmp/libomptarget/plugins-nextgen/common/src/PluginInterface.cpp
+++ b/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();
 }
 
diff --git a/openmp/libomptarget/src/device.cpp b/openmp/libomptarget/src/device.cpp
index 67edc559e8ede..8394928230667 100644
--- a/openmp/libomptarget/src/device.cpp
+++ b/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;