Update default emscripten cache directory

Now that emscripten uses an in-tree cache directory there is no
need to copy the pre-built libraries around.

See: WebAssembly/waterfall#644

Also for the sake of older versions of emscripten explictly set
EM_CACHE environment variable to point to the in-tree cache
directory.

Author: sbc100

emsdk.py

@@ -1455,17 +1455,13 @@ def generate_dot_emscripten(active_tools):
   if embedded:
     cfg += 'import os\n'
     cfg += "emsdk_path = os.path.dirname(os.environ.get('EM_CONFIG')).replace('\\\\', '/')\n"
-    cfg += "CACHE = '%s'\n" % sdk_path('.emscripten_cache')
 
   # Different tools may provide the same activated configs; the latest to be
   # activated is the relevant one.
   activated_config = OrderedDict()
   for tool in active_tools:
-    tool_cfg = tool.activated_config()
-    if tool_cfg:
-      for specific_cfg in tool_cfg.split(';'):
-        name, value = specific_cfg.split('=')
-        activated_config[name] = value
+    for name, value in tool.activated_config().items():
+      activated_config[name] = value
 
   if 'NODE_JS' not in activated_config:
     node_fallback = which('nodejs')
@@ -1474,7 +1470,7 @@ def generate_dot_emscripten(active_tools):
     activated_config['NODE_JS'] = "'%s'" % node_fallback
 
   for name, value in activated_config.items():
-    cfg += name + ' = ' + value + '\n'
+    cfg += name + " = '" + value + "'\n"
 
   cfg += '''\
 TEMP_DIR = '%s'
@@ -1493,11 +1489,9 @@ def generate_dot_emscripten(active_tools):
   with open(dot_emscripten_path(), "w") as text_file:
     text_file.write(cfg)
 
-  # Clear old cached emscripten content.
+  # Clear old emscripten content.
   try:
-    remove_tree(os.path.join(emscripten_config_directory, ".emscripten_cache"))
     os.remove(os.path.join(emscripten_config_directory, ".emscripten_sanity"))
-    os.remove(os.path.join(emscripten_config_directory, ".emscripten_cache__last_clear"))
   except:
     pass
 
@@ -1620,10 +1614,14 @@ def installation_dir(self):
   # Returns the configuration item that needs to be added to .emscripten to make
   # this Tool active for the current user.
   def activated_config(self):
-    if hasattr(self, 'activated_cfg'):
-      return to_unix_path(self.expand_vars(self.activated_cfg))
-    else:
-      return ''
+    if not hasattr(self, 'activated_cfg'):
+      return {}
+    config = OrderedDict()
+    expanded = to_unix_path(self.expand_vars(self.activated_cfg))
+    for specific_cfg in expanded.split(';'):
+      name, value = specific_cfg.split('=')
+      config[name] = value.strip("'")
+    return config
 
   def activated_environment(self):
     if hasattr(self, 'activated_env'):
@@ -1727,20 +1725,18 @@ def is_active(self):
         return False
 
     activated_cfg = self.activated_config()
-    if activated_cfg == '':
+    if not activated_cfg:
       return len(deps) > 0
 
-    activated_cfg = activated_cfg.split(';')
-    for cfg in activated_cfg:
-      cfg = cfg.strip()
-      key, value = parse_key_value(cfg)
+    for key, value in activated_cfg.items():
       if key not in dot_emscripten:
         debug_print(str(self) + ' is not active, because key="' + key + '" does not exist in .emscripten')
         return False
 
       # If running in embedded mode, all paths are stored dynamically relative
       # to the emsdk root, so normalize those first.
       dot_emscripten_key = dot_emscripten[key].replace("emsdk_path + '", "'" + emsdk_path())
+      dot_emscripten_key = dot_emscripten_key.strip("'")
       if dot_emscripten_key != value:
         debug_print(str(self) + ' is not active, because key="' + key + '" has value "' + dot_emscripten_key + '" but should have value "' + value + '"')
         return False
@@ -2448,31 +2444,6 @@ def run_emcc(tools_to_activate):
         return
 
 
-def emscripten_cache_directory():
-  return os.path.join(emscripten_config_directory, ".emscripten_cache")
-
-
-# Copy over any emscripten cache contents that were pregenerated. This avoids
-# the user needing to immediately build libc etc. on first run.
-def copy_pregenerated_cache(tools_to_activate):
-  for tool in tools_to_activate:
-    pregenerated_cache = getattr(tool, 'pregenerated_cache', None)
-    if not pregenerated_cache:
-      continue
-    for cache_dir in pregenerated_cache:
-      # Finish the install of an emscripten-releases build.
-      install_path = to_native_path(sdk_path(tool.expand_vars(tool.install_path)))
-      in_cache = os.path.join(install_path, 'lib', cache_dir)
-      if not os.path.exists(in_cache):
-        continue
-      out_cache = os.path.join(emscripten_cache_directory(), cache_dir)
-      os.makedirs(out_cache)
-      for filename in os.listdir(in_cache):
-        debug_print('Copying %s to cache: %s' % (filename, out_cache))
-        shutil.copy2(os.path.join(in_cache, filename),
-                     os.path.join(out_cache, filename))
-
-
 # Reconfigure .emscripten to choose the currently activated toolset, set PATH
 # and other environment variables.
 # Returns the full list of deduced tools that are now active.
@@ -2489,8 +2460,6 @@ def set_active_tools(tools_to_activate, permanently_activate):
   # copy the cache contents.
   run_emcc(tools_to_activate)
 
-  copy_pregenerated_cache(tools_to_activate)
-
   # Construct a .bat script that will be invoked to set env. vars and PATH
   if WINDOWS:
     env_string = construct_env(tools_to_activate, False)
@@ -2628,15 +2597,14 @@ def construct_env(tools_to_activate, permanent):
   em_config_path = os.path.normpath(dot_emscripten_path())
   if to_unix_path(os.environ.get('EM_CONFIG', '')) != to_unix_path(em_config_path):
     env_vars_to_add += [('EM_CONFIG', em_config_path)]
-  if emscripten_config_directory == emsdk_path():
-    # Remove this once emscripten support CACHE in the config file:
-    # https://github.com/emscripten-core/emscripten/pull/11091
-    em_cache_dir = sdk_path('.emscripten_cache')
-    if to_unix_path(os.environ.get('EM_CACHE', '')) != to_unix_path(em_cache_dir):
-      env_vars_to_add += [('EM_CACHE', em_cache_dir)]
-    mkdir_p(em_cache_dir)
 
   for tool in tools_to_activate:
+    config = tool.activated_config()
+    if 'EMSCRIPTEN_ROOT' in config:
+      # For older emscripten versions that don't use this default we export
+      # EM_CACHE.
+      em_cache_dir = os.path.join(config['EMSCRIPTEN_ROOT'], 'cache')
+      env_vars_to_add += [('EM_CACHE', em_cache_dir)]
     envs = tool.activated_environment()
     for env in envs:
       key, value = parse_key_value(env)