Move all addOn<X> functions into a JS library. (#23565)

- Make all `addOn<X>` functions have a corresponding compile time
version `addAt<X>`.
- Make all the `addOn<X>` functions use the compile time `addAt<X>`
helper so the `addOn<X>` code is not emitted if it is not needed.
- Add the missing injection points to the minimal runtime.
- Add tests to ensure the order in regular runtime and mininimal
runtime.


Automatic rebaseline of codesize expectations. NFC
This is an automatic change generated by tools/maint/rebaseline_tests.py.

The following (85) test expectation files were updated by
running the tests with `--rebaseline`:

```
browser/test_small_js_flags.js.size: 4248 => 4150 [-98 bytes / -2.31%]
other/codesize/test_codesize_cxx_ctors1.gzsize: 8288 => 8263 [-25 bytes / -0.30%]
other/codesize/test_codesize_cxx_ctors1.jssize: 20132 => 20087 [-45 bytes / -0.22%]
other/codesize/test_codesize_cxx_ctors2.gzsize: 8273 => 8252 [-21 bytes / -0.25%]
other/codesize/test_codesize_cxx_ctors2.jssize: 20111 => 20065 [-46 bytes / -0.23%]
other/codesize/test_codesize_cxx_except.gzsize: 9289 => 9269 [-20 bytes / -0.22%]
other/codesize/test_codesize_cxx_except.jssize: 23900 => 23854 [-46 bytes / -0.19%]
other/codesize/test_codesize_cxx_except_wasm.gzsize: 8231 => 8207 [-24 bytes / -0.29%]
other/codesize/test_codesize_cxx_except_wasm.jssize: 20024 => 19979 [-45 bytes / -0.22%]
other/codesize/test_codesize_cxx_except_wasm_legacy.gzsize: 8231 => 8207 [-24 bytes / -0.29%]
other/codesize/test_codesize_cxx_except_wasm_legacy.jssize: 20024 => 19979 [-45 bytes / -0.22%]
other/codesize/test_codesize_cxx_lto.gzsize: 8296 => 8279 [-17 bytes / -0.20%]
other/codesize/test_codesize_cxx_lto.jssize: 20208 => 20162 [-46 bytes / -0.23%]
other/codesize/test_codesize_cxx_mangle.gzsize: 9292 => 9277 [-15 bytes / -0.16%]
other/codesize/test_codesize_cxx_mangle.jssize: 23900 => 23854 [-46 bytes / -0.19%]
other/codesize/test_codesize_cxx_noexcept.gzsize: 8288 => 8263 [-25 bytes / -0.30%]
other/codesize/test_codesize_cxx_noexcept.jssize: 20132 => 20087 [-45 bytes / -0.22%]
other/codesize/test_codesize_cxx_wasmfs.gzsize: 3496 => 3471 [-25 bytes / -0.72%]
other/codesize/test_codesize_cxx_wasmfs.jssize: 7541 => 7496 [-45 bytes / -0.60%]
other/codesize/test_codesize_files_js_fs.gzsize: 7591 => 7571 [-20 bytes / -0.26%]
other/codesize/test_codesize_files_js_fs.jssize: 18679 => 18634 [-45 bytes / -0.24%]
other/codesize/test_codesize_files_wasmfs.gzsize: 2736 => 2712 [-24 bytes / -0.88%]
other/codesize/test_codesize_files_wasmfs.jssize: 5851 => 5807 [-44 bytes / -0.75%]
other/codesize/test_codesize_hello_O0.gzsize: 7874 => 7872 [-2 bytes / -0.03%]
other/codesize/test_codesize_hello_O0.jssize: 20992 => 20962 [-30 bytes / -0.14%]
other/codesize/test_codesize_hello_O1.gzsize: 2605 => 2579 [-26 bytes / -1.00%]
other/codesize/test_codesize_hello_O1.jssize: 6719 => 6647 [-72 bytes / -1.07%]
other/codesize/test_codesize_hello_O2.gzsize: 2257 => 2232 [-25 bytes / -1.11%]
other/codesize/test_codesize_hello_O2.jssize: 4645 => 4600 [-45 bytes / -0.97%]
other/codesize/test_codesize_hello_O3.gzsize: 2212 => 2190 [-22 bytes / -0.99%]
other/codesize/test_codesize_hello_O3.jssize: 4587 => 4542 [-45 bytes / -0.98%]
other/codesize/test_codesize_hello_Os.gzsize: 2212 => 2190 [-22 bytes / -0.99%]
other/codesize/test_codesize_hello_Os.jssize: 4587 => 4542 [-45 bytes / -0.98%]
other/codesize/test_codesize_hello_Oz.gzsize: 2212 => 2190 [-22 bytes / -0.99%]
other/codesize/test_codesize_hello_Oz.jssize: 4587 => 4542 [-45 bytes / -0.98%]
other/codesize/test_codesize_hello_dylink.gzsize: 5931 => 5914 [-17 bytes / -0.29%]
other/codesize/test_codesize_hello_dylink.jssize: 13106 => 13075 [-31 bytes / -0.24%]
other/codesize/test_codesize_hello_export_nothing.gzsize: 1620 => 1600 [-20 bytes / -1.23%]
other/codesize/test_codesize_hello_export_nothing.jssize: 3500 => 3471 [-29 bytes / -0.83%]
other/codesize/test_codesize_hello_wasmfs.gzsize: 2212 => 2190 [-22 bytes / -0.99%]
other/codesize/test_codesize_hello_wasmfs.jssize: 4587 => 4542 [-45 bytes / -0.98%]
other/codesize/test_codesize_libcxxabi_message_O3.gzsize: 1814 => 1791 [-23 bytes / -1.27%]
other/codesize/test_codesize_libcxxabi_message_O3.jssize: 3863 => 3825 [-38 bytes / -0.98%]
other/codesize/test_codesize_libcxxabi_message_O3_standalone.gzsize: 1858 => 1825 [-33 bytes / -1.78%]
other/codesize/test_codesize_libcxxabi_message_O3_standalone.jssize: 3920 => 3868 [-52 bytes / -1.33%]
other/codesize/test_codesize_mem_O3.gzsize: 2265 => 2242 [-23 bytes / -1.02%]
other/codesize/test_codesize_mem_O3.jssize: 4755 => 4710 [-45 bytes / -0.95%]
other/codesize/test_codesize_mem_O3_grow.gzsize: 2413 => 2391 [-22 bytes / -0.91%]
other/codesize/test_codesize_mem_O3_grow.jssize: 5039 => 4994 [-45 bytes / -0.89%]
other/codesize/test_codesize_mem_O3_grow_standalone.gzsize: 2117 => 2087 [-30 bytes / -1.42%]
other/codesize/test_codesize_mem_O3_grow_standalone.jssize: 4457 => 4405 [-52 bytes / -1.17%]
other/codesize/test_codesize_mem_O3_standalone.gzsize: 2083 => 2047 [-36 bytes / -1.73%]
other/codesize/test_codesize_mem_O3_standalone.jssize: 4389 => 4337 [-52 bytes / -1.18%]
other/codesize/test_codesize_mem_O3_standalone_lib.gzsize: 1844 => 1819 [-25 bytes / -1.36%]
other/codesize/test_codesize_mem_O3_standalone_lib.jssize: 3919 => 3881 [-38 bytes / -0.97%]
other/codesize/test_codesize_mem_O3_standalone_narg.gzsize: 1858 => 1825 [-33 bytes / -1.78%]
other/codesize/test_codesize_mem_O3_standalone_narg.jssize: 3920 => 3868 [-52 bytes / -1.33%]
other/codesize/test_codesize_mem_O3_standalone_narg_flto.gzsize: 1858 => 1825 [-33 bytes / -1.78%]
other/codesize/test_codesize_mem_O3_standalone_narg_flto.jssize: 3920 => 3868 [-52 bytes / -1.33%]
other/codesize/test_codesize_minimal_64.gzsize: 1389 => 1332 [-57 bytes / -4.10%]
other/codesize/test_codesize_minimal_64.jssize: 2908 => 2827 [-81 bytes / -2.79%]
other/codesize/test_codesize_minimal_O0.gzsize: 6381 => 6331 [-50 bytes / -0.78%]
other/codesize/test_codesize_minimal_O0.jssize: 16805 => 16687 [-118 bytes / -0.70%]
other/codesize/test_codesize_minimal_O1.gzsize: 1470 => 1408 [-62 bytes / -4.22%]
other/codesize/test_codesize_minimal_O1.jssize: 3423 => 3301 [-122 bytes / -3.56%]
other/codesize/test_codesize_minimal_O2.gzsize: 1329 => 1273 [-56 bytes / -4.21%]
other/codesize/test_codesize_minimal_O2.jssize: 2656 => 2574 [-82 bytes / -3.09%]
other/codesize/test_codesize_minimal_O3.gzsize: 1294 => 1238 [-56 bytes / -4.33%]
other/codesize/test_codesize_minimal_O3.jssize: 2605 => 2524 [-81 bytes / -3.11%]
other/codesize/test_codesize_minimal_Os.gzsize: 1294 => 1238 [-56 bytes / -4.33%]
other/codesize/test_codesize_minimal_Os.jssize: 2605 => 2524 [-81 bytes / -3.11%]
other/codesize/test_codesize_minimal_Oz-ctors.gzsize: 1290 => 1223 [-67 bytes / -5.19%]
other/codesize/test_codesize_minimal_Oz-ctors.jssize: 2599 => 2503 [-96 bytes / -3.69%]
other/codesize/test_codesize_minimal_Oz.gzsize: 1294 => 1238 [-56 bytes / -4.33%]
other/codesize/test_codesize_minimal_Oz.jssize: 2605 => 2524 [-81 bytes / -3.11%]
other/codesize/test_codesize_minimal_esm.gzsize: 1495 => 1436 [-59 bytes / -3.95%]
other/codesize/test_codesize_minimal_esm.jssize: 3074 => 2995 [-79 bytes / -2.57%]
other/codesize/test_codesize_minimal_pthreads.gzsize: 4152 => 4114 [-38 bytes / -0.92%]
other/codesize/test_codesize_minimal_pthreads.jssize: 8634 => 8564 [-70 bytes / -0.81%]
other/codesize/test_codesize_minimal_wasmfs.gzsize: 1294 => 1238 [-56 bytes / -4.33%]
other/codesize/test_codesize_minimal_wasmfs.jssize: 2605 => 2524 [-81 bytes / -3.11%]
other/test_INCOMING_MODULE_JS_API.js.size: 3639 => 3540 [-99 bytes / -2.72%]
other/test_unoptimized_code_size.js.size: 52550 => 51969 [-581 bytes / -1.11%]
other/test_unoptimized_code_size_no_asserts.js.size: 28168 => 27535 [-633 bytes / -2.25%]
other/test_unoptimized_code_size_strict.js.size: 51198 => 50401 [-797 bytes / -1.56%]

Average change: -1.48% (-5.19% - -0.03%)
```

Author: brendandahl

src/jsifier.mjs

@@ -14,6 +14,9 @@ import {
   ATEXITS,
   ATINITS,
   ATPOSTCTORS,
+  ATPRERUNS,
+  ATMAINS,
+  ATPOSTRUNS,
   defineI64Param,
   indentify,
   makeReturn64,
@@ -786,8 +789,11 @@ var proxiedFunctionTable = [
           warnings: warningOccured(),
           asyncFuncs,
           libraryDefinitions: LibraryManager.libraryDefinitions,
+          ATPRERUNS: ATPRERUNS.join('\n'),
           ATINITS: ATINITS.join('\n'),
           ATPOSTCTORS: ATPOSTCTORS.join('\n'),
+          ATMAINS: ATMAINS.join('\n'),
+          ATPOSTRUNS: ATPOSTRUNS.join('\n'),
           ATEXITS: ATEXITS.join('\n'),
         }),
     );

src/lib/libcore.js

@@ -2296,6 +2296,68 @@ addToLibrary({
 
   $noExitRuntime: "{{{ makeModuleReceiveExpr('noExitRuntime', !EXIT_RUNTIME) }}}",
 
+  // The following addOn<X> functions are for adding runtime callbacks at
+  // various executions points. Each addOn<X> function has a corresponding
+  // compiled time version named addAt<X> that will instead inline during
+  // compilation (see parseTools.mjs).
+  // Note: if there are both runtime and compile time code, the runtime
+  // callbacks will be invoked before the compile time code.
+
+  // See ATPRERUNS in parseTools.mjs for more information.
+  $onPreRuns: [],
+  $onPreRuns__internal: true,
+  $onPreRuns__deps: ['$callRuntimeCallbacks'],
+  $onPreRuns__postset: () => {
+    ATPRERUNS.unshift('callRuntimeCallbacks(onPreRuns);');
+  },
+  $addOnPreRun__deps: ['$onPreRuns'],
+  $addOnPreRun: (cb) => onPreRuns.unshift(cb),
+  // See ATINITS in parseTools.mjs for more information.
+  $onInits: [],
+  $onInits__internal: true,
+  $onInits__deps: ['$callRuntimeCallbacks'],
+  $onInits__postset: () => {
+    ATINITS.unshift('callRuntimeCallbacks(onInits);');
+  },
+  $addOnInit__deps: ['$onInits'],
+  $addOnInit: (cb) => onInits.unshift(cb),
+  // See ATPOSTCTORS in parseTools.mjs for more information.
+  $onPostCtors: [],
+  $onPostCtors__internal: true,
+  $onPostCtors__deps: ['$callRuntimeCallbacks'],
+  $onPostCtors__postset: () =>  {
+    ATPOSTCTORS.unshift('callRuntimeCallbacks(onPostCtors);');
+  },
+  $addOnPostCtor__deps: ['$onPostCtors'],
+  $addOnPostCtor: (cb) => onPostCtors.unshift(cb),
+  // See ATMAINS in parseTools.mjs for more information.
+  $onMains: [],
+  $onMains__internal: true,
+  $onMains__deps: ['$callRuntimeCallbacks'],
+  $onMains__postset: () => {
+    ATMAINS.unshift('callRuntimeCallbacks(onMains);');
+  },
+  $addOnPreMain__deps: ['$onMains'],
+  $addOnPreMain: (cb) => onMains.unshift(cb),
+  // See ATEXITS in parseTools.mjs for more information.
+  $onExits: [],
+  $onExits__internal: true,
+  $onExits__deps: ['$callRuntimeCallbacks'],
+  $onExits__postset: () => {
+    ATEXITS.unshift('callRuntimeCallbacks(onExits);');
+  },
+  $addOnExit__deps: ['$onExits'],
+  $addOnExit: (cb) => onExits.unshift(cb),
+  // See ATPOSTRUNS in parseTools.mjs for more information.
+  $onPostRuns: [],
+  $onPostRuns__internal: true,
+  $onPostRuns__deps: ['$callRuntimeCallbacks'],
+  $onPostRuns__postset: () => {
+    ATPOSTRUNS.unshift('callRuntimeCallbacks(onPostRuns);');
+  },
+  $addOnPostRun__deps: ['$onPostRuns'],
+  $addOnPostRun: (cb) => onPostRuns.unshift(cb),
+
   // 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.

src/lib/libdylink.js

@@ -612,6 +612,7 @@ var LibraryDylink = {
     '$currentModuleWeakSymbols',
     '$updateTableMap',
     '$wasmTable',
+    '$addOnPostCtor',
   ],
   $loadWebAssemblyModule: (binary, flags, libName, localScope, handle) => {
 #if DYLINK_DEBUG
@@ -859,7 +860,7 @@ var LibraryDylink = {
               init();
             } else {
               // we aren't ready to run compiled code yet
-              __ATPOSTCTOR__.push(init);
+              addOnPostCtor(init);
             }
           }
 #if PTHREADS

src/lib/libglut.js

@@ -304,7 +304,7 @@ var LibraryGLUT = {
   glutGetModifiers__proxy: 'sync',
   glutGetModifiers: () => GLUT.modifiers,
 
-  glutInit__deps: ['$Browser'],
+  glutInit__deps: ['$Browser', '$addOnExit'],
   glutInit__proxy: 'sync',
   glutInit: (argcp, argv) => {
     // Ignore arguments
@@ -342,7 +342,7 @@ var LibraryGLUT = {
       }
     });
 
-    __ATEXIT__.push(() => {
+    addOnExit(() => {
       if (isTouchDevice) {
         window.removeEventListener("touchmove", GLUT.touchHandler, true);
         window.removeEventListener("touchstart", GLUT.touchHandler, true);

src/lib/libhtml5.js

@@ -9,6 +9,7 @@ var LibraryHTML5 = {
 #if PTHREADS
     '_emscripten_run_callback_on_thread',
 #endif
+    '$addOnExit',
   ],
   $JSEvents: {
 
@@ -49,7 +50,7 @@ var LibraryHTML5 = {
 
     // When the C runtime exits via exit(), we unregister all event handlers
     // added by this library to be nice and clean.
-    // Track in this field whether we have yet registered that __ATEXIT__ handler.
+    // Track in this field whether we have yet registered that onExit handler.
     removeEventListenersRegistered: false,
 
 #if HTML5_SUPPORT_DEFERRING_USER_SENSITIVE_REQUESTS
@@ -74,7 +75,7 @@ var LibraryHTML5 = {
 #if EXIT_RUNTIME
     registerRemoveEventListeners() {
       if (!JSEvents.removeEventListenersRegistered) {
-        __ATEXIT__.push(JSEvents.removeAllEventListeners);
+        addOnExit(JSEvents.removeAllEventListeners);
         JSEvents.removeEventListenersRegistered = true;
       }
     },

src/lib/libpthread.js

@@ -36,6 +36,7 @@ var LibraryPThread = {
   $PThread__deps: ['_emscripten_thread_init',
                    '$terminateWorker',
                    '$cleanupThread',
+                   '$addOnPreRun',
 #if MAIN_MODULE
                    '$markAsFinished',
 #endif

src/modules.mjs

@@ -427,11 +427,6 @@ function exportRuntime() {
   // All possible runtime elements that can be exported
   let runtimeElements = [
     'run',
-    'addOnPreRun',
-    'addOnInit',
-    'addOnPreMain',
-    'addOnExit',
-    'addOnPostRun',
     'addRunDependency',
     'removeRunDependency',
     'out',

src/parseTools.mjs

@@ -731,30 +731,54 @@ function makeEval(code) {
   return ret;
 }
 
-export const ATINITS = [];
+// Add code to run soon after the Wasm module has been loaded. This is the first
+// injection point before all the other addAt<X> functions below. The code will
+// be executed after the runtime `onPreRuns` callbacks.
+export const ATPRERUNS = [];
+function addAtPreRun(code) {
+  ATPRERUNS.push(code);
+}
 
 // Add code to run after the Wasm module is loaded, but before static
-// constructors and main (if applicable). The code will be executed before the
-// runtime `__ATINIT__` callbacks.
+// constructors and main (if applicable). The code will be executed after the
+// runtime `onInits` callbacks.
+export const ATINITS = [];
 function addAtInit(code) {
   ATINITS.push(code);
 }
 
-export const ATPOSTCTORS = [];
-
 // Add code to run after static constructors, but before main (if applicable).
+// The code will be executed after the runtime `onPostCtors` callbacks.
+export const ATPOSTCTORS = [];
 function addAtPostCtor(code) {
   ATPOSTCTORS.push(code);
 }
 
-export const ATEXITS = [];
+// Add code to run right before main is called. This is only available if the
+// the Wasm module has a main function. The code will be executed after the
+// runtime `onMains` callbacks.
+export const ATMAINS = [];
+function addAtPreMain(code) {
+  ATMAINS.push(code);
+}
 
+// Add code to run after main has executed and the runtime is shutdown. This is
+// only available when the Wasm module has a main function and -sEXIT_RUNTIME is
+// set. The code will be executed after the runtime `onExits` callbacks.
+export const ATEXITS = [];
 function addAtExit(code) {
   if (EXIT_RUNTIME) {
     ATEXITS.push(code);
   }
 }
 
+// Add code to run after main and ATEXITS (if applicable). The code will be
+// executed after the runtime `onPostRuns` callbacks.
+export const ATPOSTRUNS = [];
+function addAtPostRun(code) {
+  ATPOSTRUNS.push(code);
+}
+
 function makeRetainedCompilerSettings() {
   const ignore = new Set();
   if (STRICT) {
@@ -1093,7 +1117,11 @@ function ENVIRONMENT_IS_WORKER_THREAD() {
 
 addToCompileTimeContext({
   ATEXITS,
+  ATPRERUNS,
   ATINITS,
+  ATPOSTCTORS,
+  ATMAINS,
+  ATPOSTRUNS,
   FOUR_GB,
   LONG_TYPE,
   POINTER_HEAP,
@@ -1111,8 +1139,11 @@ addToCompileTimeContext({
   ENVIRONMENT_IS_MAIN_THREAD,
   ENVIRONMENT_IS_WORKER_THREAD,
   addAtExit,
+  addAtPreRun,
   addAtInit,
   addAtPostCtor,
+  addAtPreMain,
+  addAtPostRun,
   asyncIf,
   awaitIf,
   buildStringArray,

src/postamble.js

@@ -42,7 +42,7 @@ var mainArgs = undefined;
 #endif
 #if ASSERTIONS
   assert(runDependencies == 0, 'cannot call main when async dependencies remain! (listen on Module["onRuntimeInitialized"])');
-  assert(__ATPRERUN__.length == 0, 'cannot call main when preRun functions remain to be called');
+  assert(typeof onPreRuns === 'undefined' || onPreRuns.length == 0, 'cannot call main when preRun functions remain to be called');
 #endif
 
   var entryFunction = {{{ getEntryFunction() }}};

src/postamble_minimal.js

@@ -13,6 +13,7 @@ function run() {
   emscriptenMemoryProfiler.onPreloadComplete();
 #endif
 
+  <<< ATMAINS >>>
 #if PROXY_TO_PTHREAD
   // User requested the PROXY_TO_PTHREAD option, so call a stub main which
   // pthread_create()s a new thread that will call the user's real main() for
@@ -22,7 +23,6 @@ function run() {
   var ret = _main();
 
 #if EXIT_RUNTIME
-  callRuntimeCallbacks(__ATEXIT__);
   <<< ATEXITS >>>
 #if PTHREADS
   PThread.terminateAllThreads();
@@ -43,6 +43,7 @@ function run() {
 #if STACK_OVERFLOW_CHECK
   checkStackCookie();
 #endif
+  <<< ATPOSTRUNS >>>
 }
 #endif
 
@@ -217,6 +218,7 @@ WebAssembly.instantiate(Module['wasm'], imports).then((output) => {
 #endif
   updateMemoryViews();
 #endif
+  <<< ATPRERUNS >>>
 
   initRuntime(wasmExports);
 #if PTHREADS