inferReactivePlaces() — react Function Reference

Source Code

compiler/packages/babel-plugin-react-compiler/src/Inference/InferReactivePlaces.ts lines 205–366

export function inferReactivePlaces(fn: HIRFunction): void {
  const reactiveIdentifiers = new ReactivityMap(findDisjointMutableValues(fn));
  const stableIdentifierSources = new StableSidemap(fn.env);
  for (const param of fn.params) {
    const place = param.kind === 'Identifier' ? param : param.place;
    reactiveIdentifiers.markReactive(place);
  }

  const isReactiveControlledBlock = createControlDominators(fn, place =>
    reactiveIdentifiers.isReactive(place),
  );

  do {
    for (const [, block] of fn.body.blocks) {
      let hasReactiveControl = isReactiveControlledBlock(block.id);

      for (const phi of block.phis) {
        if (reactiveIdentifiers.isReactive(phi.place)) {
          // Already marked reactive on a previous pass
          continue;
        }
        let isPhiReactive = false;
        for (const [, operand] of phi.operands) {
          if (reactiveIdentifiers.isReactive(operand)) {
            isPhiReactive = true;
            break;
          }
        }
        if (isPhiReactive) {
          reactiveIdentifiers.markReactive(phi.place);
        } else {
          for (const [pred] of phi.operands) {
            if (isReactiveControlledBlock(pred)) {
              reactiveIdentifiers.markReactive(phi.place);
              break;
            }
          }
        }
      }
      for (const instruction of block.instructions) {
        stableIdentifierSources.handleInstruction(instruction);
        const {value} = instruction;
        let hasReactiveInput = false;
        /*
         * NOTE: we want to mark all operands as reactive or not, so we
         * avoid short-circuiting here
         */
        for (const operand of eachInstructionValueOperand(value)) {
          const reactive = reactiveIdentifiers.isReactive(operand);
          hasReactiveInput ||= reactive;
        }

        /**
         * Hooks and the 'use' operator are sources of reactivity because
         * they can access state (for hooks) or context (for hooks/use).
         *
         * Technically, `use` could be used to await a non-reactive promise,
         * but we are conservative and assume that the value could be reactive.
         */
        if (
          value.kind === 'CallExpression' &&
          (getHookKind(fn.env, value.callee.identifier) != null ||
            isUseOperator(value.callee.identifier))
        ) {
          hasReactiveInput = true;
        } else if (
          value.kind === 'MethodCall' &&
          (getHookKind(fn.env, value.property.identifier) != null ||
            isUseOperator(value.property.identifier))
        ) {
          hasReactiveInput = true;
        }

        if (hasReactiveInput) {
          for (const lvalue of eachInstructionLValue(instruction)) {
            /**
             * Note that it's not correct to mark all stable-typed identifiers
             * as non-reactive, since ternaries and other value blocks can
             * produce reactive identifiers typed as these.
             * (e.g. `props.cond ? setState1 : setState2`)
             */