Make noExitRuntime into a library symbol (emscripten-core#20336)

Hopefully we can completely remove this symbols at some point, but converting into a library symbol at least means it only gets added when needed.
sbc100 · Oct 2, 2023 · 4e72237 · 4e72237
1 parent 00e3406
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Showing 39 changed files with 84 additions and 38 deletions.
diff --git a/ChangeLog.md b/ChangeLog.md
@@ -20,6 +20,11 @@ See docs/process.md for more on how version tagging works.
 
 3.1.47 (in development)
 -----------------------
+- The `noExitRuntime` global is now a JS library symbol that will only be
+  included as needed.  User of `noExitRuntime` will now need to declare a
+  dependency on it.  It will get implicitly included if `noExitRuntime` is part
+  of `INCOMING_MODULE_JS_API.` (which it is by default), or it can be added to
+  either `DEFAULT_LIBRARY_FUNCS_TO_INCLUDE` or `noExitRuntime`. (#20336)
 - The egl, html5, sdl and webgpu libraries now support basic functionality with
   `-sMEMORY64`. (#20276)
 - Value types in `emscripten/html5.h` that correspond the WebIDL `long` type are

diff --git a/emcc.py b/emcc.py
@@ -1804,6 +1804,9 @@ def phase_linker_setup(options, state, newargs):
   system_libpath = '-L' + str(cache.get_lib_dir(absolute=True))
   add_link_flag(state, sys.maxsize, system_libpath)
 
+  if 'noExitRuntime' in settings.INCOMING_MODULE_JS_API:
+    settings.DEFAULT_LIBRARY_FUNCS_TO_INCLUDE.append('$noExitRuntime')
+
   if settings.OPT_LEVEL >= 1:
     default_setting('ASSERTIONS', 0)
 

diff --git a/src/jsifier.js b/src/jsifier.js
@@ -487,6 +487,12 @@ function(${args}) {
         if (typeof dep == 'function') {
           return dep();
         }
+        // $noExitRuntime is special since there are conditional usages of it
+        // in library.js and library_pthread.js.  These happen before deps are
+        // processed so depending on it via `__deps` doesn't work.
+        if (dep === '$noExitRuntime') {
+          error('noExitRuntime cannot be referenced via __deps mechansim.  Use DEFAULT_LIBRARY_FUNCS_TO_INCLUDE or EXPORTED_RUNTIME_METHODS')
+        }
         return addFromLibrary(dep, `${symbol}, referenced by ${dependent}`, dep === aliasTarget);
       }
       let contentText;

diff --git a/src/library.js b/src/library.js
@@ -3269,8 +3269,10 @@ addToLibrary({
 
   _emscripten_runtime_keepalive_clear__proxy: 'sync',
   _emscripten_runtime_keepalive_clear: () => {
-#if !MINIMAL_RUNTIME
+#if isSymbolNeeded('$noExitRuntime')
     noExitRuntime = false;
+#endif
+#if !MINIMAL_RUNTIME
     runtimeKeepaliveCounter = 0;
 #endif
   },
@@ -3388,7 +3390,11 @@ addToLibrary({
   $runtimeKeepaliveCounter: 0,
 
   $keepRuntimeAlive__deps: ['$runtimeKeepaliveCounter'],
+#if isSymbolNeeded('$noExitRuntime')
   $keepRuntimeAlive: () => noExitRuntime || runtimeKeepaliveCounter > 0,
+#else
+  $keepRuntimeAlive: () => runtimeKeepaliveCounter > 0,
+#endif
 
   // Callable in pthread without __proxy needed.
   $runtimeKeepalivePush__deps: ['$runtimeKeepaliveCounter'],
@@ -3646,6 +3652,8 @@ addToLibrary({
   $wasmTable: undefined,
 #endif
 
+  $noExitRuntime: "{{{ makeModuleReceiveExpr('noExitRuntime', !EXIT_RUNTIME) }}}",
+
   // We used to define these globals unconditionally in support code.
   // Instead, we now define them here so folks can pull it in explicitly, on
   // demand.

diff --git a/src/library_pthread.js b/src/library_pthread.js
@@ -129,7 +129,7 @@ var LibraryPThread = {
 #endif
 #endif
 
-#if !MINIMAL_RUNTIME
+#if isSymbolNeeded('$noExitRuntime')
       // The default behaviour for pthreads is always to exit once they return
       // from their entry point (or call pthread_exit).  If we set noExitRuntime
       // to true here on pthreads they would never complete and attempt to

diff --git a/src/parseTools.js b/src/parseTools.js
@@ -744,6 +744,18 @@ function expectToReceiveOnModule(name) {
   return INCOMING_MODULE_JS_API.has(name);
 }
 
+// Return true if the user requested that a library symbol be included
+// either via DEFAULT_LIBRARY_FUNCS_TO_INCLUDE or EXPORTED_RUNTIME_METHODS.
+function isSymbolNeeded(symName) {
+  if (DEFAULT_LIBRARY_FUNCS_TO_INCLUDE.includes(symName)) {
+    return true;
+  }
+  if (symName.startsWith('$') && symName.slice(1) in EXPORTED_RUNTIME_METHODS) {
+    return true;
+  }
+  return false;
+}
+
 function makeRemovedModuleAPIAssert(moduleName, localName) {
   if (!ASSERTIONS) return '';
   if (!localName) localName = moduleName;

diff --git a/src/preamble.js b/src/preamble.js
@@ -24,7 +24,6 @@ out = err = () => {};
 #endif
 
 {{{ makeModuleReceiveWithVar('wasmBinary') }}}
-{{{ makeModuleReceiveWithVar('noExitRuntime', undefined, EXIT_RUNTIME ? 'false' : 'true') }}}
 
 #if WASM != 2 && MAYBE_WASM2JS
 #if !WASM2JS

diff --git a/test/other/metadce/test_metadce_cxx_ctors1.jssize b/test/other/metadce/test_metadce_cxx_ctors1.jssize
@@ -1 +1 @@
-25031
+25027
diff --git a/test/other/metadce/test_metadce_cxx_ctors2.jssize b/test/other/metadce/test_metadce_cxx_ctors2.jssize
@@ -1 +1 @@
-24999
+24995
diff --git a/test/other/metadce/test_metadce_cxx_except.jssize b/test/other/metadce/test_metadce_cxx_except.jssize
@@ -1 +1 @@
-29164
+29160
diff --git a/test/other/metadce/test_metadce_cxx_except_wasm.jssize b/test/other/metadce/test_metadce_cxx_except_wasm.jssize
@@ -1 +1 @@
-24805
+24801
diff --git a/test/other/metadce/test_metadce_cxx_mangle.jssize b/test/other/metadce/test_metadce_cxx_mangle.jssize
@@ -1 +1 @@
-29163
+29159
diff --git a/test/other/metadce/test_metadce_cxx_noexcept.jssize b/test/other/metadce/test_metadce_cxx_noexcept.jssize
@@ -1 +1 @@
-25031
+25027
diff --git a/test/other/metadce/test_metadce_cxx_wasmfs.jssize b/test/other/metadce/test_metadce_cxx_wasmfs.jssize
@@ -1 +1 @@
-12440
+12436
diff --git a/test/other/metadce/test_metadce_files_js_fs.jssize b/test/other/metadce/test_metadce_files_js_fs.jssize
@@ -1 +1 @@
-19930
+19926
diff --git a/test/other/metadce/test_metadce_files_wasmfs.jssize b/test/other/metadce/test_metadce_files_wasmfs.jssize
@@ -1 +1 @@
-7070
+7065
diff --git a/test/other/metadce/test_metadce_hello_O0.jssize b/test/other/metadce/test_metadce_hello_O0.jssize
@@ -1 +1 @@
-23549
+23522
diff --git a/test/other/metadce/test_metadce_hello_O1.jssize b/test/other/metadce/test_metadce_hello_O1.jssize
@@ -1 +1 @@
-8062
+8058
diff --git a/test/other/metadce/test_metadce_hello_O2.jssize b/test/other/metadce/test_metadce_hello_O2.jssize
@@ -1 +1 @@
-5724
+5719
diff --git a/test/other/metadce/test_metadce_hello_O3.jssize b/test/other/metadce/test_metadce_hello_O3.jssize
@@ -1 +1 @@
-5571
+5566
diff --git a/test/other/metadce/test_metadce_hello_Os.jssize b/test/other/metadce/test_metadce_hello_Os.jssize
@@ -1 +1 @@
-5571
+5566
diff --git a/test/other/metadce/test_metadce_hello_Oz.jssize b/test/other/metadce/test_metadce_hello_Oz.jssize
@@ -1 +1 @@
-5537
+5533
diff --git a/test/other/metadce/test_metadce_hello_dylink.jssize b/test/other/metadce/test_metadce_hello_dylink.jssize
@@ -1 +1 @@
-14810
+14806
diff --git a/test/other/metadce/test_metadce_hello_wasmfs.jssize b/test/other/metadce/test_metadce_hello_wasmfs.jssize
@@ -1 +1 @@
-5571
+5566
diff --git a/test/other/metadce/test_metadce_libcxxabi_message_O3.jssize b/test/other/metadce/test_metadce_libcxxabi_message_O3.jssize
@@ -1 +1 @@
-4855
+4850
diff --git a/test/other/metadce/test_metadce_libcxxabi_message_O3_standalone.jssize b/test/other/metadce/test_metadce_libcxxabi_message_O3_standalone.jssize
@@ -1 +1 @@
-4904
+4899
diff --git a/test/other/metadce/test_metadce_mem_O3.jssize b/test/other/metadce/test_metadce_mem_O3.jssize
@@ -1 +1 @@
-5752
+5748
diff --git a/test/other/metadce/test_metadce_mem_O3_grow.jssize b/test/other/metadce/test_metadce_mem_O3_grow.jssize
@@ -1 +1 @@
-6074
+6070
diff --git a/test/other/metadce/test_metadce_mem_O3_grow_standalone.jssize b/test/other/metadce/test_metadce_mem_O3_grow_standalone.jssize
@@ -1 +1 @@
-5468
+5464
diff --git a/test/other/metadce/test_metadce_mem_O3_standalone.jssize b/test/other/metadce/test_metadce_mem_O3_standalone.jssize
@@ -1 +1 @@
-5399
+5395
diff --git a/test/other/metadce/test_metadce_mem_O3_standalone_lib.jssize b/test/other/metadce/test_metadce_mem_O3_standalone_lib.jssize
@@ -1 +1 @@
-4906
+4901
diff --git a/test/other/metadce/test_metadce_mem_O3_standalone_narg.jssize b/test/other/metadce/test_metadce_mem_O3_standalone_narg.jssize
@@ -1 +1 @@
-4904
+4899
diff --git a/test/other/metadce/test_metadce_mem_O3_standalone_narg_flto.jssize b/test/other/metadce/test_metadce_mem_O3_standalone_narg_flto.jssize
@@ -1 +1 @@
-4904
+4899
diff --git a/test/other/metadce/test_metadce_minimal_O0.jssize b/test/other/metadce/test_metadce_minimal_O0.jssize
@@ -1 +1 @@
-20027
+20004
diff --git a/test/other/test_unoptimized_code_size.js.size b/test/other/test_unoptimized_code_size.js.size
@@ -1 +1 @@
-58384
+58355
diff --git a/test/other/test_unoptimized_code_size_no_asserts.js.size b/test/other/test_unoptimized_code_size_no_asserts.js.size
@@ -1 +1 @@
-31749
+31752
diff --git a/test/other/test_unoptimized_code_size_strict.js.size b/test/other/test_unoptimized_code_size_strict.js.size
@@ -1 +1 @@
-57098
+57069
diff --git a/test/test_other.py b/test/test_other.py
@@ -13888,17 +13888,17 @@ def test_webidl_empty(self):
 
   def test_noExitRuntime(self):
     onexit_called = 'onExit called'
-    create_file('pre.js', f'Module.onExit = () => console.log("${onexit_called}");')
+    create_file('pre.js', f'Module.onExit = () => console.log("${onexit_called}");\n')
     self.emcc_args += ['--pre-js=pre.js']
     self.set_setting('EXIT_RUNTIME')
 
-    # Normally with EXIT_RUNTIME set we expect onExit to be called;
+    # Normally, with EXIT_RUNTIME set we expect onExit to be called.
     output = self.do_runf(test_file('hello_world.c'), 'hello, world')
     self.assertContained(onexit_called, output)
 
-    # However, if we set `Module.noExitRuntime = true`, then we expect
-    # it not to be called.
-    create_file('noexit.js', 'Module.noExitRuntime = true;')
+    # However, if we set `Module.noExitRuntime = true`, then it should
+    # not be called.
+    create_file('noexit.js', 'Module.noExitRuntime = true;\n')
     output = self.do_runf(test_file('hello_world.c'), 'hello, world', emcc_args=['--pre-js=noexit.js'])
     self.assertNotContained(onexit_called, output)
 
@@ -13907,3 +13907,15 @@ def test_noExitRuntime(self):
     create_file('noexit_oninit.js', 'Module.preRun = () => { noExitRuntime = true; }')
     output = self.do_runf(test_file('hello_world.c'), 'hello, world', emcc_args=['--pre-js=noexit_oninit.js'])
     self.assertNotContained(onexit_called, output)
+
+  def test_noExitRuntime_deps(self):
+    create_file('lib.js', r'''
+addToLibrary({
+  foo__deps: ['$noExitRuntime'],
+  foo: () => {
+    return 0;
+  }
+});
+''')
+    err = self.expect_fail([EMCC, test_file('hello_world.c'), '--js-library=lib.js', '-sDEFAULT_LIBRARY_FUNCS_TO_INCLUDE=foo'])
+    self.assertContained('error: noExitRuntime cannot be referenced via __deps mechansim', err)
diff --git a/tools/gen_struct_info.py b/tools/gen_struct_info.py
@@ -250,6 +250,7 @@ def inspect_headers(headers, cflags):
                                '-nostdlib',
                                compiler_rt,
                                '-sBOOTSTRAPPING_STRUCT_INFO',
+                               '-sINCOMING_MODULE_JS_API=',
                                '-sSTRICT',
                                '-sASSERTIONS=0'] + node_flags