Group JS library exports together, along with JS runtime exports. NFC (#24039)

This is in preparation for #24005 which delays the processing and
creation of Module object itself until later in some cases.

Author: sbc100

src/jsifier.mjs

@@ -734,15 +734,6 @@ function(${args}) {
         }
         contentText = `var ${mangled} = ${snippet};`;
       }
-      // asm module exports are done in emscripten.py, after the asm module is ready. Here
-      // we also export library methods as necessary.
-      if ((EXPORT_ALL || EXPORTED_FUNCTIONS.has(mangled)) && !isStub) {
-        if (MODULARIZE === 'instance') {
-          contentText += `\n__exp_${mangled} = ${mangled};`;
-        } else {
-          contentText += `\nModule['${mangled}'] = ${mangled};`;
-        }
-      }
       // Relocatable code needs signatures to create proper wrappers.
       if (sig && RELOCATABLE) {
         if (!WASM_BIGINT) {

src/modules.mjs

@@ -405,17 +405,21 @@ function addMissingLibraryStubs(unusedLibSymbols) {
   return rtn;
 }
 
+function exportSymbol(name) {
+  if (MODULARIZE === 'instance') {
+    return `__exp_${name} = ${name};`;
+  }
+  return `Module['${name}'] = ${name};`;
+}
+
 // export parts of the JS runtime that the user asked for
-function exportRuntime() {
+function exportRuntimeSymbols() {
   // optionally export something.
   function maybeExport(name) {
     // If requested to be exported, export it.  HEAP objects are exported
     // separately in updateMemoryViews
     if (EXPORTED_RUNTIME_METHODS.has(name) && !name.startsWith('HEAP')) {
-      if (MODULARIZE === 'instance') {
-        return `__exp_${name} = ${name};`;
-      }
-      return `Module['${name}'] = ${name};`;
+      return exportSymbol(name);
     }
   }
 
@@ -509,6 +513,7 @@ function exportRuntime() {
   }
 
   const exports = runtimeElements.map(maybeExport);
+  exports.unshift('// Begin runtime exports');
   const results = exports.filter((name) => name);
 
   if (ASSERTIONS && !EXPORT_ALL) {
@@ -540,8 +545,23 @@ function exportRuntime() {
   return results.join('\n') + '\n';
 }
 
+function exportLibrarySymbols() {
+  const results = ['// Begin JS library exports'];
+  for (const ident of librarySymbols) {
+    if (EXPORT_ALL || EXPORTED_FUNCTIONS.has(ident)) {
+      results.push(exportSymbol(ident));
+    }
+  }
+
+  return results.join('\n') + '\n';
+}
+
+function exportJSSymbols() {
+  return exportRuntimeSymbols() + exportLibrarySymbols();
+}
+
 addToCompileTimeContext({
-  exportRuntime,
+  exportJSSymbols,
   loadStructInfo,
   LibraryManager,
   librarySymbols,

src/postamble.js

@@ -24,7 +24,7 @@ if (ENVIRONMENT_IS_WORKER) {
 #include "deterministic.js"
 #endif
 
-{{{ exportRuntime() }}}
+{{{ exportJSSymbols() }}}
 
 #if ASSERTIONS
 var calledRun;

src/postamble_minimal.js

@@ -5,7 +5,7 @@
  */
 
 // === Auto-generated postamble setup entry stuff ===
-{{{ exportRuntime() }}}
+{{{ exportJSSymbols() }}}
 
 #if HAS_MAIN // Only if user is exporting a C main(), we will generate a run() function that can be used to launch main.
 function run() {

test/other/test_unoptimized_code_size.js.size

@@ -1 +1 @@
-51566
+51619

test/other/test_unoptimized_code_size_no_asserts.js.size

@@ -1 +1 @@
-27275
+27327

test/other/test_unoptimized_code_size_strict.js.size

@@ -1 +1 @@
-49720
+49773