Use a single/shared implementation of @memoize. NFC (#23476)

Author: sbc100

emcc.py

@@ -45,7 +45,7 @@
 from tools import config
 from tools import cache
 from tools.settings import default_setting, user_settings, settings, MEM_SIZE_SETTINGS, COMPILE_TIME_SETTINGS
-from tools.utils import read_file, removeprefix
+from tools.utils import read_file, removeprefix, memoize
 from tools import feature_matrix
 
 logger = logging.getLogger('emcc')
@@ -422,14 +422,8 @@ def get_clang_flags(user_args):
   return flags
 
 
-cflags = None
-
-
+@memoize
 def get_cflags(user_args):
-  global cflags
-  if cflags:
-    return cflags
-
   # Flags we pass to the compiler when building C/C++ code
   # We add these to the user's flags (newargs), but not when building .s or .S assembly files
   cflags = get_clang_flags(user_args)

tools/shared.py

@@ -6,7 +6,6 @@
 from .toolchain_profiler import ToolchainProfiler
 
 from enum import Enum, unique, auto
-from functools import wraps
 from subprocess import PIPE
 import atexit
 import json
@@ -40,7 +39,7 @@
 logging.basicConfig(format='%(name)s:%(levelname)s: %(message)s', level=log_level)
 colored_logger.enable()
 
-from .utils import path_from_root, exit_with_error, safe_ensure_dirs, WINDOWS, set_version_globals
+from .utils import path_from_root, exit_with_error, safe_ensure_dirs, WINDOWS, set_version_globals, memoize
 from . import cache, tempfiles
 from . import diagnostics
 from . import config
@@ -273,22 +272,6 @@ def get_npm_cmd(name):
   return cmd
 
 
-# TODO(sbc): Replace with functools.cache, once we update to python 3.7
-def memoize(func):
-  called = False
-  result = None
-
-  @wraps(func)
-  def helper():
-    nonlocal called, result
-    if not called:
-      result = func()
-      called = True
-    return result
-
-  return helper
-
-
 @memoize
 def get_clang_version():
   if not os.path.exists(CLANG_CC):

tools/utils.py

@@ -6,6 +6,7 @@
 import os
 import shutil
 import sys
+from functools import wraps
 from pathlib import Path
 
 from . import diagnostics
@@ -98,6 +99,21 @@ def delete_contents(dirname, exclude=None):
       delete_file(entry)
 
 
+# TODO(sbc): Replace with functools.cache, once we update to python 3.7
+def memoize(func):
+  results = {}
+
+  @wraps(func)
+  def helper(*args, **kwargs):
+    assert not kwargs
+    key = (func.__name__, args)
+    if key not in results:
+      results[key] = func(*args)
+    return results[key]
+
+  return helper
+
+
 # TODO: Move this back to shared.py once importing that file becoming side effect free (i.e. it no longer requires a config).
 def set_version_globals():
   global EMSCRIPTEN_VERSION, EMSCRIPTEN_VERSION_MAJOR, EMSCRIPTEN_VERSION_MINOR, EMSCRIPTEN_VERSION_TINY

tools/webassembly.py

@@ -13,6 +13,7 @@
 import os
 import sys
 
+from .utils import memoize
 from . import utils
 
 sys.path.append(utils.path_from_root('third_party'))
@@ -55,19 +56,6 @@ def read_sleb(iobuf):
   return leb128.i.decode_reader(iobuf)[0]
 
 
-def memoize(method):
-
-  @wraps(method)
-  def wrapper(self, *args, **kwargs):
-    assert not kwargs
-    key = (method.__name__, args)
-    if key not in self._cache:
-      self._cache[key] = method(self, *args, **kwargs)
-    return self._cache[key]
-
-  return wrapper
-
-
 def once(method):
 
   @wraps(method)