Rename each shared libCall once when switching to child property tables (#2381)

packages/compiler/src/frontend/lowering/handle-properties.test.ts

@@ -0,0 +1,26 @@
+import { expect, test } from "vitest";
+import { VOID, type IrExpr, type IrFunction, type IrStmt, type SrcLoc } from "../../ir/ir.js";
+import { applyHandleProperties } from "./handle-properties.js";
+import { ENTRY_NAME, type Lowerer } from "./lowerer.js";
+
+const loc: SrcLoc = { file: "main.ts", start: 0, end: 1 };
+const fn = (name: string, body: IrStmt[]): IrFunction => ({
+  name,
+  body,
+  params: [],
+  locals: [],
+  returnType: VOID,
+  loc,
+});
+
+test("renames a libCall the IR reaches from several statements once", () => {
+  const call: IrExpr = { kind: "libCall", fn: "dyn.defineProperty", args: [], type: VOID, loc };
+  const use: IrStmt = { kind: "exprStmt", expr: call, loc };
+  const functions = [fn(ENTRY_NAME, [use, use]), fn("helper", [use])];
+  applyHandleProperties({ writesOntoChildren: true } as unknown as Lowerer, functions);
+  expect(call).toMatchObject({ kind: "libCall", fn: "child.propsDefine" });
+  expect(functions[0]!.body[0]).toMatchObject({
+    kind: "exprStmt",
+    expr: { kind: "libCall", fn: "child.propsInstall" },
+  });
+});

packages/compiler/src/frontend/lowering/handle-properties.ts

@@ -283,10 +283,11 @@ const RENAMES: ReadonlyMap<IrLibFn, IrLibFn> = new Map<IrLibFn, IrLibFn>([
  * property-table entries (in place) and installs the table in %main. */
 export function applyHandleProperties(lowerer: Lowerer, functions: IrFunction[]): void {
   if (!lowerer.writesOntoChildren && !childAdditions(lowerer).any) return;
-  const calls: (IrExpr & { kind: "libCall" })[] = [];
+  // A node the IR shares at several places is renamed once.
+  const calls = new Set<IrExpr & { kind: "libCall" }>();
   const visitor = {
     expr: (e: IrExpr): boolean => {
-      if (e.kind === "libCall" && RENAMES.has(e.fn)) calls.push(e);
+      if (e.kind === "libCall" && RENAMES.has(e.fn)) calls.add(e);
       return true;
     },
     stmt: (): boolean => true,