Remove explicit support for JAVA and running closure compiler via java

It should still be possible for a user to explictly run the java
version of closure using `EMCC_CLOSURE_ARGS=--platform=java` or
`--closure-args=--platform=java`, but this isn't something we need to
have explict support for and its not something we test.

ChangeLog.md

@@ -21,6 +21,8 @@ See docs/process.md for more on how version tagging works.
 3.1.52 (in development)
 -----------------------
 - The `--default-obj-ext` command line flag was removed. (#20917)
+- Remove JAVA from the list of `.emscripten` config file settings.  In the
+  past we used this to run the java version of closure compiler.
 
 3.1.51 - 12/13/23
 -----------------

docs/emcc.txt

@@ -268,10 +268,6 @@ Options that are modified or new in *emcc* are listed below:
        before the closure-compiled code runs, because then it will
        reuse that variable.
 
-     * If closure compiler hits an out-of-memory, try adjusting
-       "JAVA_HEAP_SIZE" in the environment (for example, to 4096m for
-       4GB).
-
      * Closure is only run if JavaScript opts are being done ("-O2" or
        above).
 

site/source/docs/building_from_source/verify_emscripten_environment.rst

@@ -21,14 +21,15 @@ Open a terminal in the directory in which you installed Emscripten (on Windows o
 
 .. note:: On Windows, invoke the tool with **emcc** instead of **./emcc**.
 
-For example, the following output reports an installation where Java is missing:
+For example, the following output reports that the correcrt version of clang
+could not be found:
 
 .. code-block:: none
   :emphasize-lines: 3
 
   emcc (Emscripten GCC-like replacement + linker emulating GNU ld) 1.21.0
   shared:INFO: (Emscripten: Running sanity checks)
-  shared:WARNING: java does not seem to exist, required for closure compiler. -O2 and above will fail. You need to define JAVA in .emscripten
+  emcc: warning: LLVM version for clang executable "/usr/bin/clang" appears incorrect (seeing "16.0", expected "18") [-Wversion-check]
 
 At this point you need to :ref:`Install and activate <fixing-missing-components-emcc>` any missing components. When everything is set up properly, ``emcc ---check`` should give no warnings, and if you just enter ``emcc`` (without any input files), it will give an error ::
 

site/source/docs/tools_reference/emcc.rst

@@ -259,7 +259,6 @@ Options that are modified or new in *emcc* are listed below:
 
     - Consider using ``-sMODULARIZE`` when using closure, as it minifies globals to names that might conflict with others in the global scope. ``MODULARIZE`` puts all the output into a function (see ``src/settings.js``).
     - Closure will minify the name of `Module` itself, by default! Using ``MODULARIZE`` will solve that as well. Another solution is to make sure a global variable called `Module` already exists before the closure-compiled code runs, because then it will reuse that variable.
-    - If closure compiler hits an out-of-memory, try adjusting ``JAVA_HEAP_SIZE`` in the environment (for example, to 4096m for 4GB).
     - Closure is only run if JavaScript opts are being done (``-O2`` or above).
 
 ``--closure-args=<args>``

tools/building.py

@@ -454,26 +454,6 @@ def get_closure_compiler():
   return cmd
 
 
-def check_closure_compiler(cmd, args, env, allowed_to_fail):
-  cmd = cmd + args + ['--version']
-  try:
-    output = run_process(cmd, stdout=PIPE, env=env).stdout
-  except Exception as e:
-    if allowed_to_fail:
-      return False
-    if isinstance(e, subprocess.CalledProcessError):
-      sys.stderr.write(e.stdout)
-    sys.stderr.write(str(e) + '\n')
-    exit_with_error('closure compiler (%s) did not execute properly!' % shared.shlex_join(cmd))
-
-  if 'Version:' not in output:
-    if allowed_to_fail:
-      return False
-    exit_with_error('unrecognized closure compiler --version output (%s):\n%s' % (shared.shlex_join(cmd), output))
-
-  return True
-
-
 # Remove this once we require python3.7 and can use std.isascii.
 # See: https://docs.python.org/3/library/stdtypes.html#str.isascii
 def isascii(s):
@@ -488,25 +468,6 @@ def isascii(s):
 def get_closure_compiler_and_env(user_args):
   env = shared.env_with_node_in_path()
   closure_cmd = get_closure_compiler()
-
-  native_closure_compiler_works = check_closure_compiler(closure_cmd, user_args, env, allowed_to_fail=True)
-  if not native_closure_compiler_works and not any(a.startswith('--platform') for a in user_args):
-    # Run with Java Closure compiler as a fallback if the native version does not work
-    user_args.append('--platform=java')
-    check_closure_compiler(closure_cmd, user_args, env, allowed_to_fail=False)
-
-  if config.JAVA and '--platform=java' in user_args:
-    # Closure compiler expects JAVA_HOME to be set *and* java.exe to be in the PATH in order
-    # to enable use the java backend.  Without this it will only try the native and JavaScript
-    # versions of the compiler.
-    java_bin = os.path.dirname(config.JAVA)
-    if java_bin:
-      def add_to_path(dirname):
-        env['PATH'] = env['PATH'] + os.pathsep + dirname
-      add_to_path(java_bin)
-      java_home = os.path.dirname(java_bin)
-      env.setdefault('JAVA_HOME', java_home)
-
   return closure_cmd, env
 
 

tools/config.py

@@ -28,7 +28,6 @@
 LLVM_ADD_VERSION = None
 CLANG_ADD_VERSION = None
 CLOSURE_COMPILER = None
-JAVA = None
 JS_ENGINES: List[List[str]] = []
 WASMER = None
 WASMTIME = None
@@ -130,7 +129,6 @@ def parse_config_file():
     'LLVM_ADD_VERSION',
     'CLANG_ADD_VERSION',
     'CLOSURE_COMPILER',
-    'JAVA',
     'JS_ENGINES',
     'WASMER',
     'WASMTIME',

tools/config_template.py

@@ -19,8 +19,6 @@
 # This engine must exist, or nothing can be compiled.
 NODE_JS = '{{{ NODE }}}' # executable
 
-JAVA = 'java' # executable
-
 ################################################################################
 #
 # Test suite options:

tools/scons/site_scons/site_tools/emscripten/emscripten.py

@@ -27,7 +27,7 @@ def generate(env, emscripten_path=None, **kw):
               'EMSCRIPTEN_SUPPRESS_USAGE_WARNING', 'NODE_PATH', 'EMCC_JSOPT_MIN_CHUNK_SIZE',
               'EMCC_JSOPT_MAX_CHUNK_SIZE', 'EMCC_CORES', 'EMCC_NO_OPT_SORT',
               'EMCC_BUILD_DIR', 'EMCC_DEBUG_SAVE', 'EMCC_SKIP_SANITY_CHECK',
-              'EM_PKG_CONFIG_PATH', 'EMCC_CLOSURE_ARGS', 'JAVA_HEAP_SIZE',
+              'EM_PKG_CONFIG_PATH', 'EMCC_CLOSURE_ARGS',
               'EMCC_FORCE_STDLIBS', 'EMCC_ONLY_FORCED_STDLIBS', 'EM_PORTS', 'IDL_CHECKS', 'IDL_VERBOSE']:
     if os.environ.get(var):
       env['ENV'][var] = os.environ.get(var)