lib: convert WeakMaps in cjs loader with private symbol properties

Symbol properties are typically more GC-efficient than using WeakMaps, since WeakMap requires ephemeron GC. `module[kModuleExportNames]` would be easier to read than `importedCJSCache.get(module).exportNames` as well. PR-URL: #52095 Backport-PR-URL: #53500 Reviewed-By: Geoffrey Booth <[email protected]> Reviewed-By: Joyee Cheung <[email protected]> Reviewed-By: Antoine du Hamel <[email protected]>

Author: legendecas

lib/internal/modules/cjs/loader.js

@@ -50,7 +50,6 @@ const{
  ReflectSet,
  RegExpPrototypeExec,
  SafeMap,
- SafeWeakMap,
  String,
  StringPrototypeCharAt,
  StringPrototypeCharCodeAt,
@@ -62,25 +61,50 @@ const{
  StringPrototypeStartsWith,
  Symbol,
 }=primordials;
+const{
+privateSymbols: {
+ module_source_private_symbol,
+ module_export_names_private_symbol,
+ module_circular_visited_private_symbol,
+ module_export_private_symbol,
+ module_parent_private_symbol,
+},
+}=internalBinding('util');
 
 const{ kEvaluated }=internalBinding('module_wrap');
 
-// Map used to store CJS parsing data or for ESM loading.
-constimportedCJSCache=newSafeWeakMap();
+// Internal properties for Module instances.
+/**
+ * Cached{@link Module} source string.
+ */
+constkModuleSource=module_source_private_symbol;
+/**
+ * Cached{@link Module} export names for ESM loader.
+ */
+constkModuleExportNames=module_export_names_private_symbol;
+/**
+ *{@link Module} circular dependency visited flag.
+ */
+constkModuleCircularVisited=module_circular_visited_private_symbol;
 /**
- * Map of already-loaded CJS modules to use.
+ * {@link Module} export object snapshot for ESM loader.
  */
-constcjsExportsCache=newSafeWeakMap();
-constrequiredESMSourceCache=newSafeWeakMap();
+constkModuleExport=module_export_private_symbol;
+/**
+ *{@link Module} parent module.
+ */
+constkModuleParent=module_parent_private_symbol;
 
 constkIsMainSymbol=Symbol('kIsMainSymbol');
 constkIsCachedByESMLoader=Symbol('kIsCachedByESMLoader');
 constkRequiredModuleSymbol=Symbol('kRequiredModuleSymbol');
 constkIsExecuting=Symbol('kIsExecuting');
 // Set first due to cycle with ESM loader functions.
 module.exports={
- cjsExportsCache,
- importedCJSCache,
+ kModuleSource,
+ kModuleExport,
+ kModuleExportNames,
+ kModuleCircularVisited,
  initializeCJS,
  Module,
  wrapSafe,
@@ -256,8 +280,6 @@ function reportModuleNotFoundToWatchMode(basePath, extensions){
 }
 }
 
-/** @type{Map<Module, Module>} */
-constmoduleParentCache=newSafeWeakMap();
 /**
  * Create a new module instance.
  * @param{string} id
@@ -267,7 +289,7 @@ function Module(id = '', parent){
 this.id=id;
 this.path=path.dirname(id);
 setOwnProperty(this,'exports',{});
-moduleParentCache.set(this,parent);
+this[kModuleParent]=parent;
 updateChildren(parent,this,false);
 this.filename=null;
 this.loaded=false;
@@ -355,17 +377,19 @@ ObjectDefineProperty(BuiltinModule.prototype, 'isPreloading', isPreloadingDesc);
 
 /**
  * Get the parent of the current module from our cache.
+ * @this{Module}
  */
 functiongetModuleParent(){
-returnmoduleParentCache.get(this);
+returnthis[kModuleParent];
 }
 
 /**
  * Set the parent of the current module in our cache.
+ * @this{Module}
  * @param{Module} value
  */
 functionsetModuleParent(value){
-moduleParentCache.set(this,value);
+this[kModuleParent]=value;
 }
 
 letdebug=require('internal/util/debuglog').debuglog('module',(fn)=>{
@@ -955,7 +979,7 @@ function getExportsForCircularRequire(module){
 constrequiredESM=module[kRequiredModuleSymbol];
 if(requiredESM&&requiredESM.getStatus()!==kEvaluated){
 letmessage=`Cannot require() ES Module ${module.id} in a cycle.`;
-constparent=moduleParentCache.get(module);
+constparent=module[kModuleParent];
 if(parent){
 message+=` (from ${parent.filename})`;
 }
@@ -1028,25 +1052,24 @@ Module._load = function(request, parent, isMain){
 constcachedModule=Module._cache[filename];
 if(cachedModule!==undefined){
 updateChildren(parent,cachedModule,true);
-if(!cachedModule.loaded){
-// If it's not cached by the ESM loader, the loading request
-// comes from required CJS, and we can consider it a circular
-// dependency when it's cached.
-if(!cachedModule[kIsCachedByESMLoader]){
-returngetExportsForCircularRequire(cachedModule);
-}
-// If it's cached by the ESM loader as a way to indirectly pass
-// the module in to avoid creating it twice, the loading request
-// come from imported CJS. In that case use the importedCJSCache
-// to determine if it's loading or not.
-constimportedCJSMetadata=importedCJSCache.get(cachedModule);
-if(importedCJSMetadata.loading){
-returngetExportsForCircularRequire(cachedModule);
-}
-importedCJSMetadata.loading=true;
-}else{
+if(cachedModule.loaded){
 returncachedModule.exports;
 }
+// If it's not cached by the ESM loader, the loading request
+// comes from required CJS, and we can consider it a circular
+// dependency when it's cached.
+if(!cachedModule[kIsCachedByESMLoader]){
+returngetExportsForCircularRequire(cachedModule);
+}
+// If it's cached by the ESM loader as a way to indirectly pass
+// the module in to avoid creating it twice, the loading request
+// come from imported CJS. In that case use the kModuleCircularVisited
+// to determine if it's loading or not.
+if(cachedModule[kModuleCircularVisited]){
+returngetExportsForCircularRequire(cachedModule);
+}
+// This is an ESM loader created cache entry, mark it as visited and fallthrough to loading the module.
+cachedModule[kModuleCircularVisited]=true;
 }
 
 if(BuiltinModule.canBeRequiredWithoutScheme(filename)){
@@ -1190,7 +1213,7 @@ Module._resolveFilename = function(request, parent, isMain, options){
 constrequireStack=[];
 for(letcursor=parent;
 cursor;
-cursor=moduleParentCache.get(cursor)){
+cursor=cursor[kModuleParent]){
 ArrayPrototypePush(requireStack,cursor.filename||cursor.id);
 }
 letmessage=`Cannot find module '${request}'`;
@@ -1268,9 +1291,7 @@ Module.prototype.load = function(filename){
 // Create module entry at load time to snapshot exports correctly
 constexports=this.exports;
 // Preemptively cache for ESM loader.
-if(!cjsExportsCache.has(this)){
-cjsExportsCache.set(this,exports);
-}
+this[kModuleExport]=exports;
 };
 
 /**
@@ -1313,7 +1334,7 @@ function loadESMFromCJS(mod, filename){
 constisMain=mod[kIsMainSymbol];
 // TODO(joyeecheung): we may want to invent optional special handling for default exports here.
 // For now, it's good enough to be identical to what `import()` returns.
-mod.exports=cascadedLoader.importSyncForRequire(mod,filename,source,isMain,moduleParentCache.get(mod));
+mod.exports=cascadedLoader.importSyncForRequire(mod,filename,source,isMain,mod[kModuleParent]);
 }
 
 /**
@@ -1399,7 +1420,7 @@ Module.prototype._compile = function(content, filename, loadAsESM = false){
 // Only modules being require()'d really need to avoid TLA.
 if(loadAsESM){
 // Pass the source into the .mjs extension handler indirectly through the cache.
-requiredESMSourceCache.set(this,content);
+this[kModuleSource]=content;
 loadESMFromCJS(this,filename);
 return;
 }
@@ -1460,15 +1481,15 @@ Module.prototype._compile = function(content, filename, loadAsESM = false){
  * @returns{string}
  */
 functiongetMaybeCachedSource(mod,filename){
-constcached=importedCJSCache.get(mod);
+// If already analyzed the source, then it will be cached.
 letcontent;
-if(cached?.source){
-content=cached.source;
-cached.source=undefined;
+if(mod[kModuleSource]!==undefined){
+content=mod[kModuleSource];
+mod[kModuleSource]=undefined;
 }else{
 // TODO(joyeecheung): we can read a buffer instead to speed up
 // compilation.
-content=requiredESMSourceCache.get(mod)??fs.readFileSync(filename,'utf8');
+content=fs.readFileSync(filename,'utf8');
 }
 returncontent;
 }
@@ -1492,7 +1513,7 @@ Module._extensions['.js'] = function(module, filename){
 }
 
 // This is an error path because `require` of a `.js` file in a `"type": "module"` scope is not allowed.
-constparent=moduleParentCache.get(module);
+constparent=module[kModuleParent];
 constparentPath=parent?.filename;
 constpackageJsonPath=path.resolve(pkg.path,'package.json');
 constusesEsm=containsModuleSyntax(content,filename);

lib/internal/modules/esm/translators.js

@@ -43,10 +43,11 @@ const{
  stripBOM,
 }=require('internal/modules/helpers');
 const{
- cjsExportsCache,
- importedCJSCache,
  kIsCachedByESMLoader,
 Module: CJSModule,
+ kModuleSource,
+ kModuleExport,
+ kModuleExportNames,
 }=require('internal/modules/cjs/loader');
 const{ fileURLToPath, pathToFileURL,URL}=require('internal/url');
 letdebug=require('internal/util/debuglog').debuglog('esm',(fn)=>{
@@ -285,9 +286,9 @@ function createCJSModuleWrap(url, source, isMain, loadCJS = loadCJSModule){
 }
 
 letexports;
-if(cjsExportsCache.has(module)){
-exports=cjsExportsCache.get(module);
-cjsExportsCache.delete(module);
+if(module[kModuleExport]!==undefined){
+exports=module[kModuleExport];
+module[kModuleExport]=undefined;
 }else{
 ({ exports }=module);
 }
@@ -366,18 +367,16 @@ translators.set('commonjs', async function commonjsStrategy(url, source,
 functioncjsPreparseModuleExports(filename,source){
 // TODO: Do we want to keep hitting the user mutable CJS loader here?
 letmodule=CJSModule._cache[filename];
-if(module){
-constcached=importedCJSCache.get(module);
-if(cached){
-return{ module,exportNames: cached.exportNames};
-}
+if(module&&module[kModuleExportNames]!==undefined){
+return{ module,exportNames: module[kModuleExportNames]};
 }
 constloaded=Boolean(module);
 if(!loaded){
 module=newCJSModule(filename);
 module.filename=filename;
 module.paths=CJSModule._nodeModulePaths(module.path);
 module[kIsCachedByESMLoader]=true;
+module[kModuleSource]=source;
 CJSModule._cache[filename]=module;
 }
 
@@ -392,7 +391,7 @@ function cjsPreparseModuleExports(filename, source){
 constexportNames=newSafeSet(newSafeArrayIterator(exports));
 
 // Set first for cycles.
-importedCJSCache.set(module,{ source,exportNames});
+module[kModuleExportNames]=exportNames;
 
 if(reexports.length){
 module.filename=filename;

src/env_properties.h

@@ -22,6 +22,11 @@
  V(contextify_context_private_symbol, "node:contextify:context") \
  V(decorated_private_symbol, "node:decorated") \
  V(host_defined_option_symbol, "node:host_defined_option_symbol") \
+ V(module_source_private_symbol, "node:module_source") \
+ V(module_export_names_private_symbol, "node:module_export_names") \
+ V(module_circular_visited_private_symbol, "node:module_circular_visited") \
+ V(module_export_private_symbol, "node:module_export") \
+ V(module_parent_private_symbol, "node:module_parent") \
  V(napi_type_tag, "node:napi:type_tag") \
  V(napi_wrapper, "node:napi:wrapper") \
  V(untransferable_object_private_symbol, "node:untransferableObject") \