[llvm] [Libomptarget] Remove requires information from plugin (PR #80345)

[Joseph Huber via llvm-commits]

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

>From 3c6f6ace67fbcb5add1ff0d13fa89476a475eb65 Mon Sep 17 00:00:00 2001
From: Joseph Huber <huberjn at outlook.com>
Date: Thu, 16 May 2024 11:06:00 -0500
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.
---
 .../common/include/PluginInterface.h              | 15 +--------------
 .../common/src/PluginInterface.cpp                | 10 ----------
 offload/src/device.cpp                            | 12 +++---------
 3 files changed, 4 insertions(+), 33 deletions(-)

diff --git a/offload/plugins-nextgen/common/include/PluginInterface.h b/offload/plugins-nextgen/common/include/PluginInterface.h
index c396099ac6252..d8d71e3e65a4a 100644
--- a/offload/plugins-nextgen/common/include/PluginInterface.h
+++ b/offload/plugins-nextgen/common/include/PluginInterface.h
@@ -958,8 +958,7 @@ struct GenericPluginTy {
 
   /// Construct a plugin instance.
   GenericPluginTy(Triple::ArchType TA)
-      : RequiresFlags(OMP_REQ_UNDEFINED), GlobalHandler(nullptr), JIT(TA),
-        RPCServer(nullptr) {}
+      : GlobalHandler(nullptr), JIT(TA), RPCServer(nullptr) {}
 
   virtual ~GenericPluginTy() {}
 
@@ -1028,12 +1027,6 @@ 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);
 
@@ -1074,9 +1067,6 @@ struct GenericPluginTy {
   /// Return the number of devices this plugin can support.
   int32_t number_of_devices();
 
-  /// Initializes the OpenMP register requires information.
-  int64_t init_requires(int64_t RequiresFlags);
-
   /// Returns non-zero if the data can be exchanged between the two devices.
   int32_t is_data_exchangable(int32_t SrcDeviceId, int32_t DstDeviceId);
 
@@ -1203,9 +1193,6 @@ struct GenericPluginTy {
   /// device was not initialized yet.
   llvm::SmallVector<GenericDeviceTy *> Devices;
 
-  /// OpenMP requires flags.
-  int64_t RequiresFlags;
-
   /// Pointer to the global handler for this plugin.
   GenericGlobalHandlerTy *GlobalHandler;
 
diff --git a/offload/plugins-nextgen/common/src/PluginInterface.cpp b/offload/plugins-nextgen/common/src/PluginInterface.cpp
index 737a8b2a4064f..253acacc3a9dc 100644
--- a/offload/plugins-nextgen/common/src/PluginInterface.cpp
+++ b/offload/plugins-nextgen/common/src/PluginInterface.cpp
@@ -1618,11 +1618,6 @@ int32_t GenericPluginTy::init_device(int32_t DeviceId) {
 
 int32_t GenericPluginTy::number_of_devices() { return getNumDevices(); }
 
-int64_t GenericPluginTy::init_requires(int64_t RequiresFlags) {
-  setRequiresFlag(RequiresFlags);
-  return OFFLOAD_SUCCESS;
-}
-
 int32_t GenericPluginTy::is_data_exchangable(int32_t SrcDeviceId,
                                              int32_t DstDeviceId) {
   return isDataExchangable(SrcDeviceId, DstDeviceId);
@@ -1964,11 +1959,6 @@ int32_t GenericPluginTy::set_device_offset(int32_t DeviceIdOffset) {
 }
 
 int32_t GenericPluginTy::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 (getRequiresFlags() & OMP_REQ_UNIFIED_SHARED_MEMORY)
-    return false;
   return getDevice(DeviceId).useAutoZeroCopy();
 }
 
diff --git a/offload/src/device.cpp b/offload/src/device.cpp
index 749b4c567f8e4..943c778278730 100644
--- a/offload/src/device.cpp
+++ b/offload/src/device.cpp
@@ -77,15 +77,7 @@ DeviceTy::~DeviceTy() {
 }
 
 llvm::Error DeviceTy::init() {
-  // Make call to init_requires if it exists for this plugin.
-  int32_t Ret = 0;
-  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);
+  int32_t Ret = RTL->init_device(RTLDeviceID);
   if (Ret != OFFLOAD_SUCCESS)
     return llvm::createStringError(llvm::inconvertibleErrorCode(),
                                    "Failed to initialize device %d\n",
@@ -285,5 +277,7 @@ void DeviceTy::dumpOffloadEntries() {
 }
 
 bool DeviceTy::useAutoZeroCopy() {
+  if (PM->getRequirements() & OMP_REQ_UNIFIED_SHARED_MEMORY)
+    return false;
   return RTL->use_auto_zero_copy(RTLDeviceID);
 }