Move normalModuleLoader hook

lib/Compilation.js

@@ -354,12 +354,7 @@ class Compilation {
 				"childCompiler",
 				"compilerName",
 				"compilerIndex"
-			]),
-
-			// TODO the following hooks are weirdly located here
-			// TODO move them for webpack 5
-			/** @type {SyncHook<object, Module>} */
-			normalModuleLoader: new SyncHook(["loaderContext", "module"])
+			])
 		});
 		/** @type {string=} */
 		this.name = undefined;

lib/HotModuleReplacementPlugin.js

@@ -16,6 +16,7 @@ const {
 	toConstantDependencyWithWebpackRequire
 } = require("./JavascriptParserHelpers");
 const MainTemplate = require("./MainTemplate");
+const NormalModule = require("./NormalModule");
 const NullFactory = require("./NullFactory");
 const RuntimeGlobals = require("./RuntimeGlobals");
 const Template = require("./Template");
@@ -461,7 +462,7 @@ class HotModuleReplacementPlugin {
 					.for("javascript/dynamic")
 					.tap("HotModuleReplacementPlugin", addParserPlugins);
 
-				compilation.hooks.normalModuleLoader.tap(
+				NormalModule.getCompilationHooks(compilation).loader.tap(
 					"HotModuleReplacementPlugin",
 					context => {
 						context.hot = true;

lib/LoaderOptionsPlugin.js

@@ -37,13 +37,9 @@ class LoaderOptionsPlugin {
 	apply(compiler) {
 		const options = this.options;
 		compiler.hooks.compilation.tap("LoaderOptionsPlugin", compilation => {
-			compilation.hooks.normalModuleLoader.tap(
+			NormalModule.getCompilationHooks(compilation).loader.tap(
 				"LoaderOptionsPlugin",
-				(context, m) => {
-					if (!(m instanceof NormalModule)) {
-						return;
-					}
-					const module = /** @type {NormalModule} */ m;
+				(context, module) => {
 					const resource = module.resource;
 					if (!resource) return;
 					const i = resource.indexOf("?");

lib/LoaderTargetPlugin.js

@@ -5,6 +5,8 @@
 
 "use strict";
 
+const NormalModule = require("./NormalModule");
+
 /** @typedef {import("./Compiler")} Compiler */
 
 class LoaderTargetPlugin {
@@ -21,7 +23,7 @@ class LoaderTargetPlugin {
 	 */
 	apply(compiler) {
 		compiler.hooks.compilation.tap("LoaderTargetPlugin", compilation => {
-			compilation.hooks.normalModuleLoader.tap(
+			NormalModule.getCompilationHooks(compilation).loader.tap(
 				"LoaderTargetPlugin",
 				loaderContext => {
 					loaderContext.target = this.target;

lib/NormalModule.js

@@ -7,12 +7,14 @@
 
 const { getContext, runLoaders } = require("loader-runner");
 const asyncLib = require("neo-async");
+const { SyncHook } = require("tapable");
 const {
 	CachedSource,
 	OriginalSource,
 	RawSource,
 	SourceMapSource
 } = require("webpack-sources");
+const Compilation = require("./Compilation");
 const Module = require("./Module");
 const ModuleBuildError = require("./ModuleBuildError");
 const ModuleError = require("./ModuleError");
@@ -79,7 +81,35 @@ makeSerializable(
  * @property {string} hash the hash value
  */
 
+/**
+ * @typedef {Object} NormalModuleCompilationHooks
+ * @property {SyncHook<object, NormalModule>} loader
+ */
+
+/** @type {WeakMap<Compilation, NormalModuleCompilationHooks>} */
+const compilationHooksMap = new WeakMap();
+
 class NormalModule extends Module {
+	/**
+	 * @param {Compilation} compilation the compilation
+	 * @returns {NormalModuleCompilationHooks} the attached hooks
+	 */
+	static getCompilationHooks(compilation) {
+		if (!(compilation instanceof Compilation)) {
+			throw new TypeError(
+				"The 'compilation' argument must be an instance of Compilation"
+			);
+		}
+		let hooks = compilationHooksMap.get(compilation);
+		if (hooks === undefined) {
+			hooks = {
+				loader: new SyncHook(["loaderContext", "module"])
+			};
+			compilationHooksMap.set(compilation, hooks);
+		}
+		return hooks;
+	}
+
 	constructor({
 		type,
 		request,
@@ -235,7 +265,11 @@ class NormalModule extends Module {
 			fs: fs
 		};
 
-		compilation.hooks.normalModuleLoader.call(loaderContext, this);
+		NormalModule.getCompilationHooks(compilation).loader.call(
+			loaderContext,
+			this
+		);
+
 		if (options.loader) {
 			Object.assign(loaderContext, options.loader);
 		}

lib/dependencies/LoaderPlugin.js

@@ -5,6 +5,7 @@
 
 "use strict";
 
+const NormalModule = require("../NormalModule");
 const LoaderDependency = require("./LoaderDependency");
 
 /** @typedef {import("../Module")} Module */
@@ -31,9 +32,9 @@ class LoaderPlugin {
 
 		compiler.hooks.compilation.tap("LoaderPlugin", compilation => {
 			const moduleGraph = compilation.moduleGraph;
-			compilation.hooks.normalModuleLoader.tap(
+			NormalModule.getCompilationHooks(compilation).loader.tap(
 				"LoaderPlugin",
-				(loaderContext, module) => {
+				loaderContext => {
 					/**
 					 * @param {string} request the request string to load the module from
 					 * @param {LoadModuleCallback} callback callback returning the loaded module or error