Make path_finder work for "nvrtc" (#553)

* Revert "Restore cuda/bindings/_bindings/cynvrtc.pyx.in as-is on main"

This reverts commit ba093f5.

* Revert "Reapply "Revert debug changes under .github/workflows""

This reverts commit 8f69f83.

* Also load nvrtc from cuda_bindings/tests/path_finder.py

* Add heuristics for nvidia_cuda_nvrtc Windows wheels.

Also fix a couple bugs discovered by ChatGPT:

* `glob.glob()` in this code return absolute paths.

* stray `error_messages = []`

* Add debug prints, mostly for `os.add_dll_directory(bin_dir)`

* Fix unfortunate silly oversight (import os missing under Windows)

* Use `win32api.LoadLibraryEx()` with suitable `flags`; also update `os.environ["PATH"]`

* Hard-wire WinBase.h constants (they are not exposed by win32con)

* Remove debug prints

* Reapply "Reapply "Revert debug changes under .github/workflows""

This reverts commit b002ff6.

Author: rwgk

cuda_bindings/cuda/bindings/_bindings/cynvrtc.pyx.in

@@ -9,13 +9,12 @@
 # This code was automatically generated with version 12.8.0. Do not modify it directly.
 {{if 'Windows' == platform.system()}}
 import os
-import site
-import struct
 import win32api
-from pywintypes import error
 {{else}}
 cimport cuda.bindings._lib.dlfcn as dlfcn
+from libc.stdint cimport uintptr_t
 {{endif}}
+from cuda.bindings import path_finder
 
 cdef bint __cuPythonInit = False
 {{if 'nvrtcGetErrorString' in found_functions}}cdef void *__nvrtcGetErrorString = NULL{{endif}}
@@ -46,64 +45,18 @@ cdef bint __cuPythonInit = False
 {{if 'nvrtcSetFlowCallback' in found_functions}}cdef void *__nvrtcSetFlowCallback = NULL{{endif}}
 
 cdef int cuPythonInit() except -1 nogil:
+    {{if 'Windows' != platform.system()}}
+    cdef void* handle = NULL
+    {{endif}}
+
     global __cuPythonInit
     if __cuPythonInit:
         return 0
     __cuPythonInit = True
 
-    # Load library
-    {{if 'Windows' == platform.system()}}
-    with gil:
-        # First check if the DLL has been loaded by 3rd parties
-        try:
-            handle = win32api.GetModuleHandle("nvrtc64_120_0.dll")
-        except:
-            handle = None
-
-        # Else try default search
-        if not handle:
-            LOAD_LIBRARY_SAFE_CURRENT_DIRS = 0x00002000
-            try:
-                handle = win32api.LoadLibraryEx("nvrtc64_120_0.dll", 0, LOAD_LIBRARY_SAFE_CURRENT_DIRS)
-            except:
-                pass
-
-        # Final check if DLLs can be found within pip installations
-        if not handle:
-            site_packages = [site.getusersitepackages()] + site.getsitepackages()
-            for sp in site_packages:
-                mod_path = os.path.join(sp, "nvidia", "cuda_nvrtc", "bin")
-                if not os.path.isdir(mod_path):
-                    continue
-                os.add_dll_directory(mod_path)
-            LOAD_LIBRARY_SEARCH_DEFAULT_DIRS = 0x00001000
-            LOAD_LIBRARY_SEARCH_DLL_LOAD_DIR = 0x00000100
-            try:
-                handle = win32api.LoadLibraryEx(
-                    # Note: LOAD_LIBRARY_SEARCH_DLL_LOAD_DIR needs an abs path...
-                    os.path.join(mod_path, "nvrtc64_120_0.dll"),
-                    0, LOAD_LIBRARY_SEARCH_DEFAULT_DIRS | LOAD_LIBRARY_SEARCH_DLL_LOAD_DIR)
-
-                # Note: nvrtc64_120_0.dll calls into nvrtc-builtins64_*.dll which is
-                # located in the same mod_path.
-                # Update PATH environ so that the two dlls can find each other
-                os.environ["PATH"] = os.pathsep.join((os.environ.get("PATH", ""), mod_path))
-            except:
-                pass
-
-        if not handle:
-            raise RuntimeError('Failed to LoadLibraryEx nvrtc64_120_0.dll')
-    {{else}}
-    handle = dlfcn.dlopen('libnvrtc.so.12', dlfcn.RTLD_NOW)
-    if handle == NULL:
-        with gil:
-            raise RuntimeError('Failed to dlopen libnvrtc.so.12')
-    {{endif}}
-
-
-    # Load function
     {{if 'Windows' == platform.system()}}
     with gil:
+        handle = path_finder.load_nvidia_dynamic_library("nvrtc")
         {{if 'nvrtcGetErrorString' in found_functions}}
         try:
             global __nvrtcGetErrorString
@@ -288,6 +241,8 @@ cdef int cuPythonInit() except -1 nogil:
         {{endif}}
 
     {{else}}
+    with gil:
+        handle = <void*><uintptr_t>path_finder.load_nvidia_dynamic_library("nvrtc")
     {{if 'nvrtcGetErrorString' in found_functions}}
     global __nvrtcGetErrorString
     __nvrtcGetErrorString = dlfcn.dlsym(handle, 'nvrtcGetErrorString')

cuda_bindings/cuda/bindings/_path_finder/find_nvidia_dynamic_library.py

@@ -31,25 +31,50 @@ def _find_so_using_nvidia_lib_dirs(libname, so_basename, error_messages, attachm
             return so_name
         # Look for a versioned library
         # Using sort here mainly to make the result deterministic.
-        for node in sorted(glob.glob(os.path.join(lib_dir, file_wild))):
-            so_name = os.path.join(lib_dir, node)
+        for so_name in sorted(glob.glob(os.path.join(lib_dir, file_wild))):
             if os.path.isfile(so_name):
                 return so_name
     _no_such_file_in_sub_dirs(nvidia_sub_dirs, file_wild, error_messages, attachments)
     return None
 
 
+def _append_to_os_environ_path(dirpath):
+    curr_path = os.environ.get("PATH")
+    os.environ["PATH"] = dirpath if curr_path is None else os.pathsep.join((curr_path, dirpath))
+
+
 def _find_dll_using_nvidia_bin_dirs(libname, error_messages, attachments):
     if libname == "nvvm":  # noqa: SIM108
         nvidia_sub_dirs = ("nvidia", "*", "nvvm", "bin")
     else:
         nvidia_sub_dirs = ("nvidia", "*", "bin")
     file_wild = libname + "*.dll"
     for bin_dir in sys_path_find_sub_dirs(nvidia_sub_dirs):
-        for node in sorted(glob.glob(os.path.join(bin_dir, file_wild))):
-            dll_name = os.path.join(bin_dir, node)
-            if os.path.isfile(dll_name):
-                return dll_name
+        dll_name = None
+        have_builtins = False
+        for path in sorted(glob.glob(os.path.join(bin_dir, file_wild))):
+            # nvidia_cuda_nvrtc_cu12-12.8.93-py3-none-win_amd64.whl:
+            #     nvidia\cuda_nvrtc\bin\
+            #         nvrtc-builtins64_128.dll
+            #         nvrtc64_120_0.alt.dll
+            #         nvrtc64_120_0.dll
+            node = os.path.basename(path)
+            if node.endswith(".alt.dll"):
+                continue
+            if "-builtins" in node:
+                have_builtins = True
+                continue
+            if dll_name is not None:
+                continue
+            if os.path.isfile(path):
+                dll_name = path
+        if dll_name is not None:
+            if have_builtins:
+                # Add the DLL directory to the search path
+                os.add_dll_directory(bin_dir)
+                # Update PATH as a fallback for dependent DLL resolution
+                _append_to_os_environ_path(bin_dir)
+            return dll_name
     _no_such_file_in_sub_dirs(nvidia_sub_dirs, file_wild, error_messages, attachments)
     return None
 
@@ -78,7 +103,6 @@ def _find_so_using_cudalib_dir(so_basename, error_messages, attachments):
             candidate_so_dirs.append(alt_dir)
         libs.reverse()
     candidate_so_names = [so_dirname + so_basename for so_dirname in candidate_so_dirs]
-    error_messages = []
     for so_name in candidate_so_names:
         if os.path.isfile(so_name):
             return so_name
@@ -98,8 +122,7 @@ def _find_dll_using_cudalib_dir(libname, error_messages, attachments):
     if cudalib_dir is None:
         return None
     file_wild = libname + "*.dll"
-    for node in sorted(glob.glob(os.path.join(cudalib_dir, file_wild))):
-        dll_name = os.path.join(cudalib_dir, node)
+    for dll_name in sorted(glob.glob(os.path.join(cudalib_dir, file_wild))):
         if os.path.isfile(dll_name):
             return dll_name
     error_messages.append(f"No such file: {file_wild}")
@@ -123,7 +146,7 @@ def find_nvidia_dynamic_library(name: str) -> str:
                 dll_name = _find_dll_using_cudalib_dir(name, error_messages, attachments)
         if dll_name is None:
             attachments = "\n".join(attachments)
-            raise RuntimeError(f"Failure finding {name}*.dll: {', '.join(error_messages)}\n{attachments}")
+            raise RuntimeError(f'Failure finding "{name}*.dll": {", ".join(error_messages)}\n{attachments}')
         return dll_name
 
     so_basename = f"lib{name}.so"
@@ -135,5 +158,5 @@ def find_nvidia_dynamic_library(name: str) -> str:
             so_name = _find_so_using_cudalib_dir(so_basename, error_messages, attachments)
     if so_name is None:
         attachments = "\n".join(attachments)
-        raise RuntimeError(f"Failure finding {so_basename}: {', '.join(error_messages)}\n{attachments}")
+        raise RuntimeError(f'Failure finding "{so_basename}": {", ".join(error_messages)}\n{attachments}')
     return so_name

cuda_bindings/cuda/bindings/_path_finder/load_nvidia_dynamic_library.py

@@ -8,7 +8,8 @@
     import win32api
 
     # Mirrors WinBase.h (unfortunately not defined already elsewhere)
-    _WINBASE_LOAD_LIBRARY_SEARCH_SYSTEM32 = 0x00000800
+    _WINBASE_LOAD_LIBRARY_SEARCH_DLL_LOAD_DIR = 0x00000100
+    _WINBASE_LOAD_LIBRARY_SEARCH_DEFAULT_DIRS = 0x00001000
 
 else:
     import ctypes
@@ -77,8 +78,9 @@ def load_nvidia_dynamic_library(name: str) -> int:
 
     dl_path = find_nvidia_dynamic_library(name)
     if sys.platform == "win32":
+        flags = _WINBASE_LOAD_LIBRARY_SEARCH_DEFAULT_DIRS | _WINBASE_LOAD_LIBRARY_SEARCH_DLL_LOAD_DIR
         try:
-            handle = win32api.LoadLibrary(dl_path)
+            handle = win32api.LoadLibraryEx(dl_path, 0, flags)
         except pywintypes.error as e:
             raise RuntimeError(f"Failed to load DLL at {dl_path}: {e}") from e
         # Use `cdef void* ptr = <void*><intptr_t>` in cython to convert back to void*

cuda_bindings/tests/path_finder.py

@@ -4,6 +4,15 @@
 
 for k, v in paths.items():
     print(f"{k}: {v}", flush=True)
+print()
 
-print(path_finder.find_nvidia_dynamic_library("nvvm"))
-print(path_finder.find_nvidia_dynamic_library("nvJitLink"))
+libnames = ("nvJitLink", "nvrtc", "nvvm")
+
+for libname in libnames:
+    print(path_finder.find_nvidia_dynamic_library(libname))
+    print()
+
+for libname in libnames:
+    print(libname)
+    print(path_finder.load_nvidia_dynamic_library(libname))
+    print()