Remove Fastcomp's Asyncify, which has been deprecated for years (#9075)

This was deprecated around when Emterpreter-Async came around, which was a long time ago. Also we now have a new Asyncify in the upstream backend, so it's a good time to remove the old one.

This will also make work on the new one easier (e.g. it had a whitelist already, and supporting two variants would be annoying).

People that still need Asyncify can use an older version (1.38.40), but upgrading to upstream and the new Asyncify is recommended.

Author: kripken

ChangeLog.md

@@ -18,6 +18,11 @@ See docs/process.md for how version tagging works.
 
 Current Trunk
 -------------
+ - Remove fastcomp's implementation of Asyncify. This has been deprecated for
+   a long time, since we added Emterpreter-Async, and now we have a new Asyncify
+   implementation in the upstream wasm backend. It is recommended to upgrade to
+   the upstream backend and use Asyncify there if you need it. (If you do still
+   need the older version, you can use 1.38.40.)
 
 v.1.38.40: 07/24/2019
 ---------------------

emcc.py

@@ -1223,6 +1223,10 @@ def check(input_file):
       shared.Settings.ERROR_ON_UNDEFINED_SYMBOLS = 0
       shared.Settings.WARN_ON_UNDEFINED_SYMBOLS = 0
 
+    if shared.Settings.ASYNCIFY:
+      if not shared.Settings.WASM_BACKEND:
+        exit_with_error('ASYNCIFY has been removed from fastcomp. There is a new implementation which can be used in the upstream wasm backend.')
+
     if shared.Settings.EMTERPRETIFY:
       shared.Settings.FINALIZE_ASM_JS = 0
       shared.Settings.SIMPLIFY_IFS = 0 # this is just harmful for emterpreting

emscripten.py

@@ -589,10 +589,6 @@ def create_backend_cmd(infile, temp_js):
     args += ['-enable-emscripten-cpp-exceptions']
     if shared.Settings.DISABLE_EXCEPTION_CATCHING == 2:
       args += ['-emscripten-cpp-exceptions-whitelist=' + ','.join(shared.Settings.EXCEPTION_CATCHING_WHITELIST or ['fake'])]
-  if shared.Settings.ASYNCIFY:
-    args += ['-emscripten-asyncify']
-    args += ['-emscripten-asyncify-functions=' + ','.join(shared.Settings.ASYNCIFY_FUNCTIONS)]
-    args += ['-emscripten-asyncify-whitelist=' + ','.join(shared.Settings.ASYNCIFY_WHITELIST)]
   if not shared.Settings.EXIT_RUNTIME:
     args += ['-emscripten-no-exit-runtime']
   if shared.Settings.WORKAROUND_IOS_9_RIGHT_SHIFT_BUG:
@@ -917,8 +913,6 @@ def get_exported_implemented_functions(all_exported_functions, all_implemented,
       funcs += ['emterpret']
       if shared.Settings.EMTERPRETIFY_ASYNC:
         funcs += ['setAsyncState', 'emtStackSave', 'emtStackRestore', 'getEmtStackMax', 'setEmtStackMax']
-    if shared.Settings.ASYNCIFY and need_asyncify(funcs):
-      funcs += ['setAsync']
 
   return sorted(set(funcs))
 
@@ -1487,10 +1481,6 @@ def make_simd_types(metadata):
   }
 
 
-def need_asyncify(exported_implemented_functions):
-  return '_emscripten_alloc_async_context' in exported_implemented_functions
-
-
 def asm_safe_heap():
   """optimized safe heap in asm, when we can"""
   return shared.Settings.SAFE_HEAP and not shared.Settings.SAFE_HEAP_LOG and not shared.Settings.RELOCATABLE
@@ -1610,11 +1600,6 @@ def create_basic_vars(exported_implemented_functions, forwarded_json, metadata):
       # wasm side modules have a specific convention for these
       basic_vars += ['__memory_base', '__table_base']
 
-  # See if we need ASYNCIFY functions
-  # We might not need them even if ASYNCIFY is enabled
-  if need_asyncify(exported_implemented_functions):
-    basic_vars += ['___async', '___async_unwind', '___async_retval', '___async_cur_frame']
-
   if shared.Settings.EMTERPRETIFY:
     basic_vars += ['EMTSTACKTOP', 'EMT_STACK_MAX', 'eb']
 
@@ -1883,13 +1868,6 @@ def create_runtime_funcs_asmjs(exports):
     # MINIMAL_RUNTIME moves stack functions to library.
     funcs = []
 
-  if need_asyncify(exports):
-    funcs.append('''
-function setAsync() {
-  ___async = 1;
-}
-''')
-
   if shared.Settings.EMTERPRETIFY:
     funcs.append('''
 function emterpret(pc) { // this will be replaced when the emterpreter code is generated; adding it here allows validation until then

site/source/docs/porting/asyncify.rst

@@ -23,7 +23,7 @@ for general background and details of how it works internally. The following
 expands on the Emscripten examples from that post.
 
 .. note:: This post talks about Asyncify using the new LLVM wasm backend.
-          There is also an older Asyncify implementation for the old fastcomp
+          There was an older Asyncify implementation for the old fastcomp
           backend. The two algorithms and implementations are entirely separate,
           so if you are using fastcomp, these docs may not be accurate - you
           should upgrade to the wasm backend and new Asyncify!

tests/test_browser.py

@@ -2666,14 +2666,7 @@ def test_codemods(self):
 
   def test_wget(self):
     create_test_file('test.txt', 'emscripten')
-    if not self.is_wasm_backend():
-      self.btest(path_from_root('tests', 'test_wget.c'), expected='1', args=['-s', 'ASYNCIFY=1'])
-      print('asyncify+emterpreter')
-      self.btest(path_from_root('tests', 'test_wget.c'), expected='1', args=['-s', 'ASYNCIFY=1', '-s', 'EMTERPRETIFY=1'])
-      print('emterpreter by itself')
-      self.btest(path_from_root('tests', 'test_wget.c'), expected='1', args=['-s', 'EMTERPRETIFY=1', '-s', 'EMTERPRETIFY_ASYNC=1'])
-    else:
-      self.btest(path_from_root('tests', 'test_wget.c'), expected='1', args=['-s', 'ASYNCIFY=1'])
+    self.btest(path_from_root('tests', 'test_wget.c'), expected='1', args=self.get_async_args())
 
   def test_wget_data(self):
     create_test_file('test.txt', 'emscripten')

tests/test_core.py

@@ -7168,14 +7168,11 @@ def test_async(self, emterpretify=False):
 
     if self.is_wasm_backend():
       self.set_setting('ASYNCIFY', 1)
+    elif emterpretify:
+      self.set_setting('EMTERPRETIFY', 1)
+      self.set_setting('EMTERPRETIFY_ASYNC', 1)
     else:
-      if not emterpretify:
-        if self.is_emterpreter():
-          self.skipTest("don't test both emterpretify and asyncify at once")
-        self.set_setting('ASYNCIFY', 1)
-      else:
-        self.set_setting('EMTERPRETIFY', 1)
-        self.set_setting('EMTERPRETIFY_ASYNC', 1)
+      self.skipTest('fastcomp Asyncify was removed')
 
     src = r'''
 #include <stdio.h>
@@ -7474,10 +7471,12 @@ def do_test_coroutine(self, additional_settings):
     self.do_run(src, '*leaf-0-100-1-101-1-102-2-103-3-104-5-105-8-106-13-107-21-108-34-109-*')
 
   @no_wasm_backend('ASYNCIFY coroutines are not yet supported in the LLVM wasm backend')
+  @no_fastcomp('ASYNCIFY has been removed from fastcomp')
   def test_coroutine_asyncify(self):
     self.do_test_coroutine({'ASYNCIFY': 1})
 
   @no_wasm_backend('ASYNCIFY is not supported in the LLVM wasm backend')
+  @no_fastcomp('ASYNCIFY has been removed from fastcomp')
   def test_asyncify_unused(self):
     # test a program not using asyncify, but the pref is set
     self.set_setting('ASYNCIFY', 1)