[SYCL] Avoid copy of plugin information (#5049)

Reuse plugin information so that it's not copied when
sycl::detail::plugin is copied

Author: sergei

sycl/source/detail/pi.cpp

@@ -346,14 +346,15 @@ int unloadPlugin(void *Library) { return unloadOsLibrary(Library); }
 // call is done to get all Interface API mapping. The plugin interface also
 // needs to setup infrastructure to route PI_CALLs to the appropriate plugins.
 // Currently, we bind to a singe plugin.
-bool bindPlugin(void *Library, PiPlugin *PluginInformation) {
+bool bindPlugin(void *Library,
+                const std::shared_ptr<PiPlugin> &PluginInformation) {
 
   decltype(::piPluginInit) *PluginInitializeFunction = (decltype(
       &::piPluginInit))(getOsLibraryFuncAddress(Library, "piPluginInit"));
   if (PluginInitializeFunction == nullptr)
     return false;
 
-  int Err = PluginInitializeFunction(PluginInformation);
+  int Err = PluginInitializeFunction(PluginInformation.get());
 
   // TODO: Compare Supported versions and check for backward compatibility.
   // Make sure err is PI_SUCCESS.
@@ -387,11 +388,11 @@ static void initializePlugins(std::vector<plugin> &Plugins) {
     std::cerr << "SYCL_PI_TRACE[all]: "
               << "No Plugins Found." << std::endl;
 
-  PiPlugin PluginInformation{
-      _PI_H_VERSION_STRING, _PI_H_VERSION_STRING, nullptr, {}};
-  PluginInformation.PiFunctionTable = {};
-
   for (unsigned int I = 0; I < PluginNames.size(); I++) {
+    std::shared_ptr<PiPlugin> PluginInformation = std::make_shared<PiPlugin>(
+        PiPlugin{_PI_H_VERSION_STRING, _PI_H_VERSION_STRING,
+                 /*Targets=*/nullptr, /*FunctionPointers=*/{}});
+
     void *Library = loadPlugin(PluginNames[I].first);
 
     if (!Library) {
@@ -404,7 +405,7 @@ static void initializePlugins(std::vector<plugin> &Plugins) {
       continue;
     }
 
-    if (!bindPlugin(Library, &PluginInformation)) {
+    if (!bindPlugin(Library, PluginInformation)) {
       if (trace(PI_TRACE_ALL)) {
         std::cerr << "SYCL_PI_TRACE[all]: "
                   << "Failed to bind PI APIs to the plugin: "

sycl/source/detail/plugin.hpp

@@ -89,7 +89,8 @@ auto packCallArguments(ArgsT &&... Args) {
 class plugin {
 public:
   plugin() = delete;
-  plugin(RT::PiPlugin Plugin, backend UseBackend, void *LibraryHandle)
+  plugin(const std::shared_ptr<RT::PiPlugin> &Plugin, backend UseBackend,
+         void *LibraryHandle)
       : MPlugin(Plugin), MBackend(UseBackend), MLibraryHandle(LibraryHandle),
         TracingMutex(std::make_shared<std::mutex>()),
         MPluginMutex(std::make_shared<std::mutex>()) {}
@@ -101,8 +102,11 @@ class plugin {
 
   ~plugin() = default;
 
-  const RT::PiPlugin &getPiPlugin() const { return MPlugin; }
-  RT::PiPlugin &getPiPlugin() { return MPlugin; }
+  const RT::PiPlugin &getPiPlugin() const { return *MPlugin; }
+  RT::PiPlugin &getPiPlugin() { return *MPlugin; }
+  const std::shared_ptr<RT::PiPlugin> &getPiPluginPtr() const {
+    return MPlugin;
+  }
 
   /// Checks return value from PI calls.
   ///
@@ -148,29 +152,30 @@ class plugin {
     uint64_t CorrelationID = pi::emitFunctionBeginTrace(PIFnName);
     auto ArgsData =
         packCallArguments<PiApiOffset>(std::forward<ArgsT>(Args)...);
-    uint64_t CorrelationIDWithArgs = pi::emitFunctionWithArgsBeginTrace(
-        static_cast<uint32_t>(PiApiOffset), PIFnName, ArgsData.data(), MPlugin);
+    uint64_t CorrelationIDWithArgs =
+        pi::emitFunctionWithArgsBeginTrace(static_cast<uint32_t>(PiApiOffset),
+                                           PIFnName, ArgsData.data(), *MPlugin);
 #endif
     RT::PiResult R;
     if (pi::trace(pi::TraceLevel::PI_TRACE_CALLS)) {
       std::lock_guard<std::mutex> Guard(*TracingMutex);
       const char *FnName = PiCallInfo.getFuncName();
       std::cout << "---> " << FnName << "(" << std::endl;
       RT::printArgs(Args...);
-      R = PiCallInfo.getFuncPtr(MPlugin)(Args...);
+      R = PiCallInfo.getFuncPtr(*MPlugin)(Args...);
       std::cout << ") ---> ";
       RT::printArgs(R);
       RT::printOuts(Args...);
       std::cout << std::endl;
     } else {
-      R = PiCallInfo.getFuncPtr(MPlugin)(Args...);
+      R = PiCallInfo.getFuncPtr(*MPlugin)(Args...);
     }
 #ifdef XPTI_ENABLE_INSTRUMENTATION
     // Close the function begin with a call to function end
     pi::emitFunctionEndTrace(CorrelationID, PIFnName);
     pi::emitFunctionWithArgsEndTrace(CorrelationIDWithArgs,
                                      static_cast<uint32_t>(PiApiOffset),
-                                     PIFnName, ArgsData.data(), R, MPlugin);
+                                     PIFnName, ArgsData.data(), R, *MPlugin);
 #endif
     return R;
   }
@@ -236,7 +241,7 @@ class plugin {
   std::shared_ptr<std::mutex> getPluginMutex() { return MPluginMutex; }
 
 private:
-  RT::PiPlugin MPlugin;
+  std::shared_ptr<RT::PiPlugin> MPlugin;
   backend MBackend;
   void *MLibraryHandle; // the handle returned from dlopen
   std::shared_ptr<std::mutex> TracingMutex;

sycl/unittests/helpers/PiMock.hpp

@@ -123,7 +123,7 @@ class PiMock {
     // Copy the PiPlugin, thus untying our to-be mock platform from other
     // platforms within the context. Reset our platform to use the new plugin.
     auto NewPluginPtr = std::make_shared<detail::plugin>(
-        OriginalPiPlugin.getPiPlugin(), OriginalPiPlugin.getBackend(),
+        OriginalPiPlugin.getPiPluginPtr(), OriginalPiPlugin.getBackend(),
         OriginalPiPlugin.getLibraryHandle());
     ImplPtr->setPlugin(NewPluginPtr);
     // Extract the new PiPlugin instance by a non-const pointer,