getAssumedInvokedFunctions() — react Function Reference

Source Code

compiler/packages/babel-plugin-react-compiler/src/HIR/CollectHoistablePropertyLoads.ts lines 685–810

function getAssumedInvokedFunctions(
  fn: HIRFunction,
  temporaries: Map<
    IdentifierId,
    {fn: LoweredFunction; mayInvoke: Set<LoweredFunction>}
  > = new Map(),
): ReadonlySet<LoweredFunction> {
  const hoistableFunctions = new Set<LoweredFunction>();
  /**
   * Step 1: Conservatively collect identifier to function expression mappings
   */
  for (const block of fn.body.blocks.values()) {
    for (const {lvalue, value} of block.instructions) {
      /**
       * Conservatively only match function expressions which can have guaranteed ssa.
       * ObjectMethods and ObjectProperties do not.
       */
      if (value.kind === 'FunctionExpression') {
        temporaries.set(lvalue.identifier.id, {
          fn: value.loweredFunc,
          mayInvoke: new Set(),
        });
      } else if (value.kind === 'StoreLocal') {
        const lvalue = value.lvalue.place.identifier;
        const maybeLoweredFunc = temporaries.get(value.value.identifier.id);
        if (maybeLoweredFunc != null) {
          temporaries.set(lvalue.id, maybeLoweredFunc);
        }
      } else if (value.kind === 'LoadLocal') {
        const maybeLoweredFunc = temporaries.get(value.place.identifier.id);
        if (maybeLoweredFunc != null) {
          temporaries.set(lvalue.identifier.id, maybeLoweredFunc);
        }
      }
    }
  }
  /**
   * Step 2: Forward pass to do analysis of assumed function calls. Note that
   * this is conservative and does not count indirect references through
   * containers (e.g. `return {cb: () => {...}})`).
   */
  for (const block of fn.body.blocks.values()) {
    for (const {lvalue, value} of block.instructions) {
      if (value.kind === 'CallExpression') {
        const callee = value.callee;
        const maybeHook = getHookKind(fn.env, callee.identifier);
        const maybeLoweredFunc = temporaries.get(callee.identifier.id);
        if (maybeLoweredFunc != null) {
          // Direct calls
          hoistableFunctions.add(maybeLoweredFunc.fn);
        } else if (maybeHook != null) {
          /**
           * Assume arguments to all hooks are safe to invoke
           */
          for (const arg of value.args) {
            if (arg.kind === 'Identifier') {
              const maybeLoweredFunc = temporaries.get(arg.identifier.id);
              if (maybeLoweredFunc != null) {
                hoistableFunctions.add(maybeLoweredFunc.fn);
              }
            }
          }
        }
      } else if (value.kind === 'JsxExpression') {
        /**
         * Assume JSX attributes and children are safe to invoke
         */
        for (const attr of value.props) {
          if (attr.kind === 'JsxSpreadAttribute') {
            continue;
          }
          const maybeLoweredFunc = temporaries.get(attr.place.identifier.id);
          if (maybeLoweredFunc != null) {
            hoistableFunctions.add(maybeLoweredFunc.fn);
          }
        }
        for (const child of value.children ?? []) {
          const maybeLoweredFunc = temporaries.get(child.identifier.id);
          if (maybeLoweredFunc != null) {
            hoistableFunctions.add(maybeLoweredFunc.fn);
          }