Cleanup use of EMCC_WASM_BACKEND env (#5327)

In some places were were checking EMCC_WASM_BACKEND
directly.

Rather than checking the environment or calculating it
based on get_llvm_target() we should consistently
using Settings.

Author: sbc100

embuilder.py

@@ -87,7 +87,7 @@ def build_port(port_name, lib_name, params):
   tasks = sys.argv[2:]
   if 'ALL' in tasks:
     tasks = ['libc', 'libc-mt', 'dlmalloc', 'dlmalloc_threadsafe', 'pthreads', 'libcxx', 'libcxx_noexcept', 'libcxxabi', 'gl', 'binaryen', 'bullet', 'freetype', 'libpng', 'ogg', 'sdl2', 'sdl2-image', 'sdl2-ttf', 'sdl2-net', 'vorbis', 'zlib']
-    if os.environ.get('EMCC_WASM_BACKEND') == '1':
+    if shared.Settings.WASM_BACKEND:
       skip_tasks = {'libc-mt', 'dlmalloc_threadsafe', 'pthreads'}
       print('Skipping building of %s, because WebAssembly does not support pthreads.' % ', '.join(skip_tasks))
       tasks = [x for x in tasks if x not in skip_tasks]
@@ -160,7 +160,7 @@ def build_port(port_name, lib_name, params):
         int main() {}
       ''', ['optimizer.2.exe'], ['-O2'])
     elif what == 'wasm_compiler_rt':
-      if shared.get_llvm_target() == shared.WASM_TARGET:
+      if shared.Settings.WASM_BACKEND:
         build('''
           int main() {}
         ''', ['wasm_compiler_rt.a'], ['-s', 'WASM=1'])

emcc.py

@@ -887,9 +887,6 @@ def check(input_file):
       if shared.Settings.ASSERTIONS:
         shared.Settings.STACK_OVERFLOW_CHECK = 2
 
-      if shared.get_llvm_target() == shared.WASM_TARGET:
-        shared.Settings.WASM_BACKEND = 1
-
       if not shared.Settings.STRICT:
         # The preprocessor define EMSCRIPTEN is deprecated. Don't pass it to code in strict mode. Code should use the define __EMSCRIPTEN__ instead.
         shared.COMPILER_OPTS += ['-DEMSCRIPTEN']

tests/test_sanity.py

@@ -724,7 +724,7 @@ def test_embuilder(self):
       ([PYTHON, 'embuilder.py', 'build', 'cocos2d'], ['building and verifying cocos2d', 'success'], True, [os.path.join('ports-builds', 'Cocos2d', 'libCocos2d.bc')]),
       ([PYTHON, 'embuilder.py', 'build', 'wasm-libc'], ['building and verifying wasm-libc', 'success'], True, ['wasm-libc.bc']),
     ]
-    if get_llvm_target() == WASM_TARGET:
+    if Settings.WASM_BACKEND:
       tests.append(([PYTHON, 'embuilder.py', 'build', 'wasm_compiler_rt'], ['building and verifying wasm_compiler_rt', 'success'], True, ['wasm_compiler_rt.a']),)
 
     for command, expected, success, result_libs in tests:

tools/cache.py

@@ -28,7 +28,7 @@ def try_remove_ending(thestring, ending):
     self.filelock = filelock.FileLock(self.filelock_name)
 
     if use_subdir:
-      if os.environ.get('EMCC_WASM_BACKEND') and os.environ.get('EMCC_WASM_BACKEND') != '0':
+      if shared.Settings.WASM_BACKEND:
         dirname = os.path.join(dirname, 'wasm')
       else:
         dirname = os.path.join(dirname, 'asmjs')

tools/shared.py

@@ -384,7 +384,7 @@ def has_wasm_target(targets):
 def check_fastcomp():
   try:
     targets = get_llc_targets()
-    if get_llvm_target() == ASM_JS_TARGET:
+    if not Settings.WASM_BACKEND:
       if not has_asm_js_target(targets):
         logging.critical('fastcomp in use, but LLVM has not been built with the JavaScript backend as a target, llc reports:')
         print >> sys.stderr, '==========================================================================='
@@ -393,15 +393,14 @@ def check_fastcomp():
         logging.critical('you can fall back to the older (pre-fastcomp) compiler core, although that is not recommended, see http://kripken.github.io/emscripten-site/docs/building_from_source/LLVM-Backend.html')
         return False
     else:
-      assert get_llvm_target() == WASM_TARGET
       if not has_wasm_target(targets):
         logging.critical('WebAssembly set as target, but LLVM has not been built with the WebAssembly backend, llc reports:')
         print >> sys.stderr, '==========================================================================='
         print >> sys.stderr, targets
         print >> sys.stderr, '==========================================================================='
         return False
 
-    if get_llvm_target() == ASM_JS_TARGET:
+    if not Settings.WASM_BACKEND:
       # check repo versions
       d = get_fastcomp_src_dir()
       shown_repo_version_error = False
@@ -501,7 +500,7 @@ def get_emscripten_version(path):
   EMSCRIPTEN_VERSION = 'unknown'
 
 def generate_sanity():
-  return EMSCRIPTEN_VERSION + '|' + LLVM_ROOT + '|' + get_clang_version() + ('_wasm' if get_llvm_target() == WASM_TARGET else '')
+  return EMSCRIPTEN_VERSION + '|' + LLVM_ROOT + '|' + get_clang_version() + ('_wasm' if Settings.WASM_BACKEND else '')
 
 def check_sanity(force=False):
   ToolchainProfiler.enter_block('sanity')
@@ -514,7 +513,7 @@ def check_sanity(force=False):
     else:
       settings_mtime = os.stat(CONFIG_FILE).st_mtime
       sanity_file = CONFIG_FILE + '_sanity'
-      if get_llvm_target() == WASM_TARGET:
+      if Settings.WASM_BACKEND:
         sanity_file += '_wasm'
       if os.path.exists(sanity_file):
         try:
@@ -955,7 +954,6 @@ def get_vanilla_file():
     if is_vanilla:
       logging.debug('check tells us to use wasm backend')
       LLVM_TARGET = WASM_TARGET
-      os.environ['EMCC_WASM_BACKEND'] = '1'
     else:
       logging.debug('check tells us to use asm.js backend')
       LLVM_TARGET = ASM_JS_TARGET
@@ -1171,6 +1169,9 @@ def load(self, args=[]):
           declare = re.sub(r'([\w\d]+)\s*=\s*(.+)', r'self.attrs["\1"]=\2;', args[i+1])
           exec declare
 
+      if get_llvm_target() == WASM_TARGET:
+        self.attrs['WASM_BACKEND'] = 1
+
     # Transforms the Settings information into emcc-compatible args (-s X=Y, etc.). Basically
     # the reverse of load_settings, except for -Ox which is relevant there but not here
     @classmethod
@@ -1340,14 +1341,21 @@ def map(self, func, tasks):
         Building.multiprocessing_pool = FakeMultiprocessor()
       else:
         child_env = [
-          # Multiprocessing pool children must have their current working directory set to a safe path that is guaranteed not to die in between of
-          # executing commands, or otherwise the pool children will have trouble spawning subprocesses of their own.
+          # Multiprocessing pool children must have their current working
+          # directory set to a safe path that is guaranteed not to die in
+          # between of executing commands, or otherwise the pool children will
+          # have trouble spawning subprocesses of their own.
           'EMCC_POOL_CWD=' + path_from_root(),
-          # Multiprocessing pool children need to avoid all calling check_vanilla() again and again,
-          # otherwise the compiler can deadlock when building system libs, because the multiprocess parent can have the Emscripten cache directory locked for write
-          # access, and the EMCC_WASM_BACKEND check also requires locked access to the cache, which the multiprocess children would not get.
-          'EMCC_WASM_BACKEND=' + os.getenv('EMCC_WASM_BACKEND', '0'),
-          'EMCC_CORES=1' # Multiprocessing pool children can't spawn their own linear number of children, that could cause a quadratic amount of spawned processes.
+          # Multiprocessing pool children need to avoid all calling
+          # check_vanilla() again and again, otherwise the compiler can deadlock
+          # when building system libs, because the multiprocess parent can have
+          # the Emscripten cache directory locked for write access, and the
+          # EMCC_WASM_BACKEND check also requires locked access to the cache,
+          # which the multiprocess children would not get.
+          'EMCC_WASM_BACKEND=%s' % Settings.WASM_BACKEND,
+          # Multiprocessing pool children can't spawn their own linear number of
+          # children, that could cause a quadratic amount of spawned processes.
+          'EMCC_CORES=1'
         ]
         Building.multiprocessing_pool = multiprocessing.Pool(processes=cores, initializer=g_multiprocessing_initializer, initargs=child_env)