Improve memory usage for parameter deoptimizations

browser/package.json

@@ -1,6 +1,6 @@
 {
   "name": "@rollup/browser",
-  "version": "3.20.2",
+  "version": "3.20.3-0",
   "description": "Next-generation ES module bundler browser build",
   "main": "dist/rollup.browser.js",
   "module": "dist/es/rollup.browser.js",

package.json

@@ -1,6 +1,6 @@
 {
   "name": "rollup",
-  "version": "3.20.2",
+  "version": "3.20.3-0",
   "description": "Next-generation ES module bundler",
   "main": "dist/rollup.js",
   "module": "dist/es/rollup.js",

src/ast/NodeInteractions.ts

@@ -6,53 +6,45 @@ export const INTERACTION_ACCESSED = 0;
 export const INTERACTION_ASSIGNED = 1;
 export const INTERACTION_CALLED = 2;
 
+// The first argument is the "this" context
 export interface NodeInteractionAccessed {
-	args: null;
-	thisArg: ExpressionEntity | null;
+	args: readonly [ExpressionEntity | null];
 	type: typeof INTERACTION_ACCESSED;
 }
 
 export const NODE_INTERACTION_UNKNOWN_ACCESS: NodeInteractionAccessed = {
-	args: null,
-	thisArg: null,
+	args: [null],
 	type: INTERACTION_ACCESSED
 };
 
+// The first argument is the "this" context, the second argument the assigned expression
 export interface NodeInteractionAssigned {
-	args: readonly [ExpressionEntity];
-	thisArg: ExpressionEntity | null;
+	args: readonly [ExpressionEntity | null, ExpressionEntity];
 	type: typeof INTERACTION_ASSIGNED;
 }
 
-export const UNKNOWN_ARG = [UNKNOWN_EXPRESSION] as const;
-
 export const NODE_INTERACTION_UNKNOWN_ASSIGNMENT: NodeInteractionAssigned = {
-	args: UNKNOWN_ARG,
-	thisArg: null,
+	args: [null, UNKNOWN_EXPRESSION],
 	type: INTERACTION_ASSIGNED
 };
 
+// The first argument is the "this" context, the other arguments are the actual arguments
 export interface NodeInteractionCalled {
-	args: readonly (ExpressionEntity | SpreadElement)[];
-	thisArg: ExpressionEntity | null;
+	args: readonly [ExpressionEntity | null, ...(ExpressionEntity | SpreadElement)[]];
 	type: typeof INTERACTION_CALLED;
 	withNew: boolean;
 }
 
-export const NO_ARGS = [];
-
 // While this is technically a call without arguments, we can compare against
-// this reference in places where precise values or thisArg would make a
+// this reference in places where precise values or this argument would make a
 // difference
 export const NODE_INTERACTION_UNKNOWN_CALL: NodeInteractionCalled = {
-	args: NO_ARGS,
-	thisArg: null,
+	args: [null],
 	type: INTERACTION_CALLED,
 	withNew: false
 };
 
-// For tracking, called and assigned are uniquely determined by their .args
-// while accessed is determined by .thisArg
+// For tracking, interactions are uniquely determined by their .args
 export type NodeInteraction =
 	| NodeInteractionAccessed
 	| NodeInteractionAssigned

src/ast/nodes/CallExpression.ts

@@ -41,11 +41,12 @@ export default class CallExpression
 			}
 		}
 		this.interaction = {
-			args: this.arguments,
-			thisArg:
+			args: [
 				this.callee instanceof MemberExpression && !this.callee.variable
 					? this.callee.object
 					: null,
+				...this.arguments
+			],
 			type: INTERACTION_CALLED,
 			withNew: false
 		};

src/ast/nodes/ConditionalExpression.ts

@@ -1,5 +1,5 @@
 import type MagicString from 'magic-string';
-import { BLANK } from '../../utils/blank';
+import { BLANK, EMPTY_ARRAY } from '../../utils/blank';
 import type { NodeRenderOptions, RenderOptions } from '../../utils/renderHelpers';
 import {
 	findFirstOccurrenceOutsideComment,
@@ -44,7 +44,9 @@ export default class ConditionalExpression extends NodeBase implements Deoptimiz
 			const unusedBranch = this.usedBranch === this.consequent ? this.alternate : this.consequent;
 			this.usedBranch = null;
 			unusedBranch.deoptimizePath(UNKNOWN_PATH);
-			for (const expression of this.expressionsToBeDeoptimized) {
+			const { expressionsToBeDeoptimized } = this;
+			this.expressionsToBeDeoptimized = EMPTY_ARRAY as unknown as DeoptimizableEntity[];
+			for (const expression of expressionsToBeDeoptimized) {
 				expression.deoptimizeCache();
 			}
 		}

src/ast/nodes/LogicalExpression.ts

@@ -1,5 +1,5 @@
 import type MagicString from 'magic-string';
-import { BLANK } from '../../utils/blank';
+import { BLANK, EMPTY_ARRAY } from '../../utils/blank';
 import {
 	findFirstOccurrenceOutsideComment,
 	findNonWhiteSpace,
@@ -54,12 +54,14 @@ export default class LogicalExpression extends NodeBase implements Deoptimizable
 			const unusedBranch = this.usedBranch === this.left ? this.right : this.left;
 			this.usedBranch = null;
 			unusedBranch.deoptimizePath(UNKNOWN_PATH);
-			for (const expression of this.expressionsToBeDeoptimized) {
+			const { context, expressionsToBeDeoptimized } = this;
+			this.expressionsToBeDeoptimized = EMPTY_ARRAY as unknown as DeoptimizableEntity[];
+			for (const expression of expressionsToBeDeoptimized) {
 				expression.deoptimizeCache();
 			}
 			// Request another pass because we need to ensure "include" runs again if
 			// it is rendered
-			this.context.requestTreeshakingPass();
+			context.requestTreeshakingPass();
 		}
 	}
 

src/ast/nodes/MemberExpression.ts

@@ -1,7 +1,7 @@
 import type MagicString from 'magic-string';
 import type { AstContext } from '../../Module';
 import type { NormalizedTreeshakingOptions } from '../../rollup/types';
-import { BLANK } from '../../utils/blank';
+import { BLANK, EMPTY_ARRAY } from '../../utils/blank';
 import { errorIllegalImportReassignment, errorMissingExport } from '../../utils/error';
 import type { NodeRenderOptions, RenderOptions } from '../../utils/renderHelpers';
 import type { DeoptimizableEntity } from '../DeoptimizableEntity';
@@ -101,8 +101,8 @@ export default class MemberExpression
 	declare propertyKey: ObjectPathKey | null;
 	declare type: NodeType.tMemberExpression;
 	variable: Variable | null = null;
-	protected declare assignmentInteraction: NodeInteractionAssigned & { thisArg: ExpressionEntity };
-	private declare accessInteraction: NodeInteractionAccessed & { thisArg: ExpressionEntity };
+	protected declare assignmentInteraction: NodeInteractionAssigned;
+	private declare accessInteraction: NodeInteractionAccessed;
 	private assignmentDeoptimized = false;
 	private bound = false;
 	private expressionsToBeDeoptimized: DeoptimizableEntity[] = [];
@@ -152,10 +152,10 @@ export default class MemberExpression
 	}
 
 	deoptimizeCache(): void {
-		const expressionsToBeDeoptimized = this.expressionsToBeDeoptimized;
-		this.expressionsToBeDeoptimized = [];
+		const { expressionsToBeDeoptimized, object } = this;
+		this.expressionsToBeDeoptimized = EMPTY_ARRAY as unknown as DeoptimizableEntity[];
 		this.propertyKey = UnknownKey;
-		this.object.deoptimizePath(UNKNOWN_PATH);
+		object.deoptimizePath(UNKNOWN_PATH);
 		for (const expression of expressionsToBeDeoptimized) {
 			expression.deoptimizeCache();
 		}
@@ -185,8 +185,8 @@ export default class MemberExpression
 		if (this.isUndefined) {
 			return undefined;
 		}
-		this.expressionsToBeDeoptimized.push(origin);
-		if (path.length < MAX_PATH_DEPTH) {
+		if (this.propertyKey !== UnknownKey && path.length < MAX_PATH_DEPTH) {
+			this.expressionsToBeDeoptimized.push(origin);
 			return this.object.getLiteralValueAtPath(
 				[this.getPropertyKey(), ...path],
 				recursionTracker,
@@ -213,8 +213,8 @@ export default class MemberExpression
 		if (this.isUndefined) {
 			return [UNDEFINED_EXPRESSION, false];
 		}
-		this.expressionsToBeDeoptimized.push(origin);
-		if (path.length < MAX_PATH_DEPTH) {
+		if (this.propertyKey !== UnknownKey && path.length < MAX_PATH_DEPTH) {
+			this.expressionsToBeDeoptimized.push(origin);
 			return this.object.getReturnExpressionWhenCalledAtPath(
 				[this.getPropertyKey(), ...path],
 				interaction,
@@ -297,7 +297,7 @@ export default class MemberExpression
 
 	initialise(): void {
 		this.propertyKey = getResolvablePropertyKey(this);
-		this.accessInteraction = { args: null, thisArg: this.object, type: INTERACTION_ACCESSED };
+		this.accessInteraction = { args: [this.object], type: INTERACTION_ACCESSED };
 	}
 
 	isSkippedAsOptional(origin: DeoptimizableEntity): boolean {
@@ -340,8 +340,7 @@ export default class MemberExpression
 
 	setAssignedValue(value: ExpressionEntity) {
 		this.assignmentInteraction = {
-			args: [value],
-			thisArg: this.object,
+			args: [this.object, value],
 			type: INTERACTION_ASSIGNED
 		};
 	}

src/ast/nodes/NewExpression.ts

@@ -53,8 +53,7 @@ export default class NewExpression extends NodeBase {
 
 	initialise(): void {
 		this.interaction = {
-			args: this.arguments,
-			thisArg: null,
+			args: [null, ...this.arguments],
 			type: INTERACTION_CALLED,
 			withNew: true
 		};

src/ast/nodes/TaggedTemplateExpression.ts

@@ -18,6 +18,7 @@ export default class TaggedTemplateExpression extends CallExpressionBase {
 	declare quasi: TemplateLiteral;
 	declare tag: ExpressionNode;
 	declare type: NodeType.tTaggedTemplateExpression;
+	private declare args: ExpressionEntity[];
 
 	bind(): void {
 		super.bind();
@@ -54,17 +55,20 @@ export default class TaggedTemplateExpression extends CallExpressionBase {
 			this.tag.include(context, includeChildrenRecursively);
 			this.quasi.include(context, includeChildrenRecursively);
 		}
-		this.tag.includeCallArguments(context, this.interaction.args);
+		this.tag.includeCallArguments(context, this.args);
 		const [returnExpression] = this.getReturnExpression();
 		if (!returnExpression.included) {
 			returnExpression.include(context, false);
 		}
 	}
 
 	initialise(): void {
+		this.args = [UNKNOWN_EXPRESSION, ...this.quasi.expressions];
 		this.interaction = {
-			args: [UNKNOWN_EXPRESSION, ...this.quasi.expressions],
-			thisArg: this.tag instanceof MemberExpression && !this.tag.variable ? this.tag.object : null,
+			args: [
+				this.tag instanceof MemberExpression && !this.tag.variable ? this.tag.object : null,
+				...this.args
+			],
 			type: INTERACTION_CALLED,
 			withNew: false
 		};

src/ast/nodes/ThisExpression.ts

@@ -23,12 +23,7 @@ export default class ThisExpression extends NodeBase {
 		path: ObjectPath,
 		recursionTracker: PathTracker
 	): void {
-		// We rewrite the parameter so that a ThisVariable can detect self-mutations
-		this.variable.deoptimizeArgumentsOnInteractionAtPath(
-			interaction.thisArg === this ? { ...interaction, thisArg: this.variable } : interaction,
-			path,
-			recursionTracker
-		);
+		this.variable.deoptimizeArgumentsOnInteractionAtPath(interaction, path, recursionTracker);
 	}
 
 	deoptimizePath(path: ObjectPath): void {

src/ast/nodes/shared/CallExpressionBase.ts

@@ -1,3 +1,4 @@
+import { EMPTY_ARRAY, EMPTY_SET } from '../../../utils/blank';
 import type { DeoptimizableEntity } from '../../DeoptimizableEntity';
 import type { HasEffectsContext } from '../../ExecutionContext';
 import type { NodeInteraction, NodeInteractionCalled } from '../../NodeInteractions';
@@ -15,36 +16,32 @@ import { NodeBase } from './Node';
 export default abstract class CallExpressionBase extends NodeBase implements DeoptimizableEntity {
 	protected declare interaction: NodeInteractionCalled;
 	protected returnExpression: [expression: ExpressionEntity, isPure: boolean] | null = null;
-	private readonly deoptimizableDependentExpressions: DeoptimizableEntity[] = [];
-	private readonly expressionsToBeDeoptimized = new Set<ExpressionEntity>();
+	private deoptimizableDependentExpressions: DeoptimizableEntity[] = [];
+	private expressionsToBeDeoptimized = new Set<ExpressionEntity>();
 
 	deoptimizeArgumentsOnInteractionAtPath(
 		interaction: NodeInteraction,
 		path: ObjectPath,
 		recursionTracker: PathTracker
 	): void {
-		const { args, thisArg } = interaction;
+		const { args } = interaction;
 		const [returnExpression, isPure] = this.getReturnExpression(recursionTracker);
 		if (isPure) return;
+		const deoptimizedExpressions = args.filter(
+			expression => !!expression && expression !== UNKNOWN_EXPRESSION
+		) as ExpressionEntity[];
+		if (deoptimizedExpressions.length === 0) return;
 		if (returnExpression === UNKNOWN_EXPRESSION) {
-			thisArg?.deoptimizePath(UNKNOWN_PATH);
-			if (args) {
-				for (const argument of args) {
-					argument.deoptimizePath(UNKNOWN_PATH);
-				}
+			for (const expression of deoptimizedExpressions) {
+				expression.deoptimizePath(UNKNOWN_PATH);
 			}
 		} else {
 			recursionTracker.withTrackedEntityAtPath(
 				path,
 				returnExpression,
 				() => {
-					if (thisArg) {
-						this.expressionsToBeDeoptimized.add(thisArg);
-					}
-					if (args) {
-						for (const argument of args) {
-							this.expressionsToBeDeoptimized.add(argument);
-						}
+					for (const expression of deoptimizedExpressions) {
+						this.expressionsToBeDeoptimized.add(expression);
 					}
 					returnExpression.deoptimizeArgumentsOnInteractionAtPath(
 						interaction,
@@ -60,10 +57,13 @@ export default abstract class CallExpressionBase extends NodeBase implements Deo
 	deoptimizeCache(): void {
 		if (this.returnExpression?.[0] !== UNKNOWN_EXPRESSION) {
 			this.returnExpression = UNKNOWN_RETURN_EXPRESSION;
-			for (const expression of this.deoptimizableDependentExpressions) {
+			const { deoptimizableDependentExpressions, expressionsToBeDeoptimized } = this;
+			this.expressionsToBeDeoptimized = EMPTY_SET;
+			this.deoptimizableDependentExpressions = EMPTY_ARRAY as unknown as DeoptimizableEntity[];
+			for (const expression of deoptimizableDependentExpressions) {
 				expression.deoptimizeCache();
 			}
-			for (const expression of this.expressionsToBeDeoptimized) {
+			for (const expression of expressionsToBeDeoptimized) {
 				expression.deoptimizePath(UNKNOWN_PATH);
 			}
 		}

src/ast/nodes/shared/Expression.ts

@@ -99,10 +99,7 @@ export const UNKNOWN_RETURN_EXPRESSION: [expression: ExpressionEntity, isPure: b
 ];
 
 export const deoptimizeInteraction = (interaction: NodeInteraction) => {
-	interaction.thisArg?.deoptimizePath(UNKNOWN_PATH);
-	if (interaction.args) {
-		for (const argument of interaction.args) {
-			argument.deoptimizePath(UNKNOWN_PATH);
-		}
+	for (const argument of interaction.args) {
+		argument?.deoptimizePath(UNKNOWN_PATH);
 	}
 };

src/ast/nodes/shared/FunctionBase.ts

@@ -49,16 +49,17 @@ export default abstract class FunctionBase extends NodeBase {
 			const { parameters } = this.scope;
 			const { args } = interaction;
 			let hasRest = false;
-			for (let position = 0; position < args.length; position++) {
+			for (let position = 0; position < args.length - 1; position++) {
 				const parameter = this.params[position];
+				// Only the "this" argument arg[0] can be null
+				const argument = args[position + 1]!;
 				if (hasRest || parameter instanceof RestElement) {
 					hasRest = true;
-					args[position].deoptimizePath(UNKNOWN_PATH);
+					argument.deoptimizePath(UNKNOWN_PATH);
 				} else if (parameter instanceof Identifier) {
-					// args[position].deoptimizePath(UNKNOWN_PATH);
-					parameters[position][0].addEntityToBeDeoptimized(args[position]);
+					parameters[position][0].addEntityToBeDeoptimized(argument);
 				} else if (parameter) {
-					args[position].deoptimizePath(UNKNOWN_PATH);
+					argument.deoptimizePath(UNKNOWN_PATH);
 				}
 			}
 		} else {