[L0] move adapter into its constructor from urAdapterGet

This restores the old behavior where urAdapterGet was essentially
a noop.

Author: pbalcer

source/adapters/level_zero/adapter.cpp

@@ -11,8 +11,6 @@
 #include "adapter.hpp"
 #include "ur_level_zero.hpp"
 
-ur_adapter_handle_t_ Adapter{};
-
 ur_result_t initPlatforms(PlatformVec &platforms) noexcept try {
   uint32_t ZeDriverCount = 0;
   ZE2UR_CALL(zeDriverGet, (&ZeDriverCount, nullptr));
@@ -36,43 +34,45 @@ ur_result_t initPlatforms(PlatformVec &platforms) noexcept try {
   return exceptionToResult(std::current_exception());
 }
 
-ur_result_t adapterStateInit() {
-  static std::once_flag ZeCallCountInitialized;
-  try {
-    std::call_once(ZeCallCountInitialized, []() {
-      if (UrL0LeaksDebug) {
-        ZeCallCount = new std::map<std::string, int>;
-      }
-    });
-  } catch (const std::bad_alloc &) {
-    return UR_RESULT_ERROR_OUT_OF_HOST_MEMORY;
-  } catch (...) {
-    return UR_RESULT_ERROR_UNKNOWN;
-  }
+ur_result_t adapterStateInit() { return UR_RESULT_SUCCESS; }
 
-  // initialize level zero only once.
-  if (Adapter.ZeResult == std::nullopt) {
-    // Setting these environment variables before running zeInit will enable the
-    // validation layer in the Level Zero loader.
-    if (UrL0Debug & UR_L0_DEBUG_VALIDATION) {
-      setEnvVar("ZE_ENABLE_VALIDATION_LAYER", "1");
-      setEnvVar("ZE_ENABLE_PARAMETER_VALIDATION", "1");
-    }
+ur_adapter_handle_t_::ur_adapter_handle_t_() {
 
-    if (getenv("SYCL_ENABLE_PCI") != nullptr) {
-      urPrint("WARNING: SYCL_ENABLE_PCI is deprecated and no longer needed.\n");
+  Adapter.PlatformCache.Compute = [](Result<PlatformVec> &result) {
+    static std::once_flag ZeCallCountInitialized;
+    try {
+      std::call_once(ZeCallCountInitialized, []() {
+        if (UrL0LeaksDebug) {
+          ZeCallCount = new std::map<std::string, int>;
+        }
+      });
+    } catch (...) {
+      result = exceptionToResult(std::current_exception());
+      return;
     }
 
-    // TODO: We can still safely recover if something goes wrong during the
-    // init. Implement handling segfault using sigaction.
+    // initialize level zero only once.
+    if (Adapter.ZeResult == std::nullopt) {
+      // Setting these environment variables before running zeInit will enable
+      // the validation layer in the Level Zero loader.
+      if (UrL0Debug & UR_L0_DEBUG_VALIDATION) {
+        setEnvVar("ZE_ENABLE_VALIDATION_LAYER", "1");
+        setEnvVar("ZE_ENABLE_PARAMETER_VALIDATION", "1");
+      }
 
-    // We must only initialize the driver once, even if urPlatformGet() is
-    // called multiple times.  Declaring the return value as "static" ensures
-    // it's only called once.
-    Adapter.ZeResult = ZE_CALL_NOCHECK(zeInit, (ZE_INIT_FLAG_GPU_ONLY));
-  }
+      if (getenv("SYCL_ENABLE_PCI") != nullptr) {
+        urPrint(
+            "WARNING: SYCL_ENABLE_PCI is deprecated and no longer needed.\n");
+      }
 
-  Adapter.PlatformCache.Compute = [](Result<PlatformVec> &result) {
+      // TODO: We can still safely recover if something goes wrong during the
+      // init. Implement handling segfault using sigaction.
+
+      // We must only initialize the driver once, even if urPlatformGet() is
+      // called multiple times.  Declaring the return value as "static" ensures
+      // it's only called once.
+      Adapter.ZeResult = ZE_CALL_NOCHECK(zeInit, (ZE_INIT_FLAG_GPU_ONLY));
+    }
     assert(Adapter.ZeResult !=
            std::nullopt); // verify that level-zero is initialized
     PlatformVec platforms;
@@ -95,9 +95,10 @@ ur_result_t adapterStateInit() {
       result = err;
     }
   };
-  return UR_RESULT_SUCCESS;
 }
 
+ur_adapter_handle_t_ Adapter{};
+
 ur_result_t adapterStateTeardown() {
   bool LeakFound = false;
 

source/adapters/level_zero/adapter.hpp

@@ -17,6 +17,7 @@
 using PlatformVec = std::vector<std::unique_ptr<ur_platform_handle_t_>>;
 
 struct ur_adapter_handle_t_ {
+  ur_adapter_handle_t_();
   std::atomic<uint32_t> RefCount = 0;
   std::mutex Mutex;
 

source/adapters/level_zero/platform.cpp

@@ -29,7 +29,8 @@ UR_APIEXPORT ur_result_t UR_APICALL urPlatformGet(
 ) {
   // Platform handles are cached for reuse. This is to ensure consistent
   // handle pointers across invocations and to improve retrieval performance.
-  if (const auto *cached_platforms = Adapter.PlatformCache->get_value()) {
+  if (const auto *cached_platforms = Adapter.PlatformCache->get_value();
+      cached_platforms) {
     uint32_t nplatforms = (uint32_t)cached_platforms->size();
     if (NumPlatforms) {
       *NumPlatforms = nplatforms;