Initial Windows support for OpenVINO backend

Author: suryasidd

backends/openvino/CMakeLists.txt

@@ -35,7 +35,11 @@ include(${EXECUTORCH_ROOT}/tools/cmake/Utils.cmake)
 add_library(openvino_backend STATIC)
 
 # Enable exceptions and RTTI for OpenVINO backend
-target_compile_options(openvino_backend PRIVATE -frtti -fexceptions)
+target_compile_options(
+  openvino_backend PRIVATE
+  $<$<CXX_COMPILER_ID:MSVC>:/GR /EHsc>
+  $<$<NOT:$<CXX_COMPILER_ID:MSVC>>:-frtti -fexceptions>
+)
 
 # Add source files for OpenVINO backend
 target_sources(

backends/openvino/runtime/OpenvinoApi.h

@@ -8,7 +8,11 @@
 
 #pragma once
 
+#ifdef _WIN32
+#include <windows.h>
+#else
 #include <dlfcn.h>
+#endif
 #include <cstddef>
 #include <cstdint>
 #include <memory>
@@ -99,7 +103,11 @@ using ov_shape_free_fn = ov_status_e (*)(ov_shape_t*);
 struct DlCloser {
   void operator()(void* handle) {
     if (handle) {
+#ifdef _WIN32
+      FreeLibrary(static_cast<HMODULE>(handle));
+#else
       dlclose(handle);
+#endif
     }
   }
 };

backends/openvino/runtime/OpenvinoBackend.cpp

@@ -23,17 +23,34 @@ namespace openvino {
 
 namespace {
 
+#ifdef _WIN32
+constexpr const char* kDefaultLibName = "openvino_c.dll";
+#else
 constexpr const char* kDefaultLibName = "libopenvino_c.so";
+#endif
 
 template <typename FuncPtr>
 FuncPtr load_symbol(void* handle, const char* name) {
+#ifdef _WIN32
+  void* sym =
+      reinterpret_cast<void*>(GetProcAddress(static_cast<HMODULE>(handle), name));
+  if (!sym) {
+    ET_LOG(
+        Error,
+        "OpenVINO: failed to resolve symbol '%s': error %lu",
+        name,
+        GetLastError());
+    return nullptr;
+  }
+#else
   dlerror(); // Clear any stale error state.
   void* sym = dlsym(handle, name);
   const char* err = dlerror();
   if (err) {
     ET_LOG(Error, "OpenVINO: failed to resolve symbol '%s': %s", name, err);
     return nullptr;
   }
+#endif
   return reinterpret_cast<FuncPtr>(sym);
 }
 
@@ -47,6 +64,19 @@ bool OpenvinoBackend::ensure_loaded() const {
     const char* lib_path = std::getenv("OPENVINO_LIB_PATH");
     const char* effective_path = lib_path ? lib_path : kDefaultLibName;
 
+#ifdef _WIN32
+    void* handle = static_cast<void*>(LoadLibrary(effective_path));
+    if (!handle) {
+      ET_LOG(
+          Error,
+          "OpenVINO runtime not found (LoadLibrary failed: error %lu). "
+          "Ensure 'openvino_c.dll' is on your PATH "
+          "(set OPENVINO_LIB_PATH), or install with: "
+          "pip install \"openvino>=2025.1.0,<2026.0.0\"",
+          GetLastError());
+      return;
+    }
+#else
     void* handle = dlopen(effective_path, RTLD_NOW | RTLD_LOCAL);
     if (!handle) {
       ET_LOG(
@@ -58,6 +88,7 @@ bool OpenvinoBackend::ensure_loaded() const {
           dlerror());
       return;
     }
+#endif
     lib_handle_.reset(handle);
 
 #define LOAD_SYM(field, symbol_name)                                  \

extension/pybindings/portable_lib.py

@@ -34,8 +34,8 @@
 logger = logging.getLogger(__name__)
 
 # Auto-discover the OpenVINO C library path from the pip-installed openvino
-# package so the C++ backend's dlopen("libopenvino_c.so") works without the
-# user having to set LD_LIBRARY_PATH or OPENVINO_LIB_PATH manually.
+# package so the C++ backend's dlopen/LoadLibrary call works without the user
+# having to set LD_LIBRARY_PATH or OPENVINO_LIB_PATH manually.
 if not os.environ.get("OPENVINO_LIB_PATH"):
     try:
         import glob
@@ -44,18 +44,24 @@
         spec = importlib.util.find_spec("openvino")
         if spec is not None and spec.submodule_search_locations:
             _ov_dir = spec.submodule_search_locations[0]
-            _ov_libs = sorted(
-                glob.glob(os.path.join(_ov_dir, "libs", "libopenvino_c.so*"))
-            )
+            _ov_libs_dir = os.path.join(_ov_dir, "libs")
+            if sys.platform == "win32":
+                _lib_pattern = os.path.join(_ov_libs_dir, "openvino_c.dll")
+            else:
+                _lib_pattern = os.path.join(_ov_libs_dir, "libopenvino_c.so*")
+            _ov_libs = sorted(glob.glob(_lib_pattern))
             if _ov_libs:
                 os.environ["OPENVINO_LIB_PATH"] = _ov_libs[0]
+                if sys.platform == "win32":
+                    os.add_dll_directory(_ov_libs_dir)
             else:
                 logger.warning(
-                    "OpenVINO package found but libopenvino_c.so not in %s; "
+                    "OpenVINO package found but %s not in %s; "
                     "set OPENVINO_LIB_PATH manually if needed",
-                    os.path.join(_ov_dir, "libs"),
+                    "openvino_c.dll" if sys.platform == "win32" else "libopenvino_c.so",
+                    _ov_libs_dir,
                 )
-            del _ov_libs, _ov_dir, spec
+            del _ov_libs, _ov_libs_dir, _lib_pattern, _ov_dir, spec
     except Exception as e:
         logger.debug("OpenVINO auto-discovery failed: %s", e)