Micro-optimize preRun/postRun handling. NFC (#22671)

Author: sbc100

src/library.js

@@ -1947,10 +1947,8 @@ addToLibrary({
 
   $callRuntimeCallbacks__internal: true,
   $callRuntimeCallbacks: (callbacks) => {
-    while (callbacks.length > 0) {
-      // Pass the module as the first argument.
-      callbacks.shift()(Module);
-    }
+    // Pass the module as the first argument.
+    callbacks.forEach((f) => f(Module));
   },
 
 #if SHRINK_LEVEL == 0 || ASYNCIFY == 2

src/postamble.js

@@ -27,6 +27,7 @@ if (ENVIRONMENT_IS_WORKER) {
 {{{ exportRuntime() }}}
 
 var calledRun;
+var calledPrerun;
 
 #if STANDALONE_WASM && MAIN_READS_PARAMS
 var mainArgs = undefined;
@@ -46,7 +47,7 @@ function callMain() {
 #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(calledPrerun, 'cannot call main without calling preRun first');
 #endif
 
   var entryFunction = {{{ getEntryFunction() }}};
@@ -191,22 +192,25 @@ function run() {
   }
 #endif
 
-  preRun();
+  if (!calledPrerun) {
+    calledPrerun = 1;
+    preRun();
 
-  // a preRun added a dependency, run will be called later
-  if (runDependencies > 0) {
+    // a preRun added a dependency, run will be called later
+    if (runDependencies > 0) {
 #if RUNTIME_DEBUG
-    dbg('run() called, but dependencies remain, so not running');
+      dbg('run() called, but dependencies remain, so not running');
 #endif
-    return;
+      return;
+    }
   }
 
   function doRun() {
     // run may have just been called through dependencies being fulfilled just in this very frame,
     // or while the async setStatus time below was happening
     if (calledRun) return;
-    calledRun = true;
-    Module['calledRun'] = true;
+    calledRun = 1;
+    Module['calledRun'] = 1;
 
     if (ABORT) return;
 

src/preamble.js

@@ -195,11 +195,10 @@ function preRun() {
   assert(!ENVIRONMENT_IS_PTHREAD); // PThreads reuse the runtime from the main thread.
 #endif
 #if expectToReceiveOnModule('preRun')
-  if (Module['preRun']) {
-    if (typeof Module['preRun'] == 'function') Module['preRun'] = [Module['preRun']];
-    while (Module['preRun'].length) {
-      addOnPreRun(Module['preRun'].shift());
-    }
+  var preRuns = Module['preRun'];
+  if (preRuns) {
+    if (typeof preRuns == 'function') preRuns = [preRuns];
+    preRuns.forEach(addOnPreRun);
   }
 #endif
   callRuntimeCallbacks(__ATPRERUN__);
@@ -289,11 +288,10 @@ function postRun() {
 #endif
 
 #if expectToReceiveOnModule('postRun')
-  if (Module['postRun']) {
-    if (typeof Module['postRun'] == 'function') Module['postRun'] = [Module['postRun']];
-    while (Module['postRun'].length) {
-      addOnPostRun(Module['postRun'].shift());
-    }
+  var postRuns = Module['postRun'];
+  if (postRuns) {
+    if (typeof postRuns == 'function') postRuns = [postRuns];
+    postRuns.forEach(addOnPostRun);
   }
 #endif
 

test/other/codesize/test_codesize_cxx_ctors1.gzsize

@@ -1 +1 @@
-8466
+8470

test/other/codesize/test_codesize_cxx_ctors1.jssize

@@ -1 +1 @@
-20855
+20801

test/other/codesize/test_codesize_cxx_ctors2.gzsize

@@ -1 +1 @@
-8450
+8452

test/other/codesize/test_codesize_cxx_ctors2.jssize

@@ -1 +1 @@
-20823
+20769

test/other/codesize/test_codesize_cxx_except.gzsize

@@ -1 +1 @@
-9488
+9497

test/other/codesize/test_codesize_cxx_except.jssize

@@ -1 +1 @@
-24699
+24645

test/other/codesize/test_codesize_cxx_except_wasm.gzsize

@@ -1 +1 @@
-8426
+8432