createControlDominators() — react Function Reference

Source Code

compiler/packages/babel-plugin-react-compiler/src/Inference/ControlDominators.ts lines 17–59

export function createControlDominators(
  fn: HIRFunction,
  isControlVariable: (place: Place) => boolean,
): ControlDominators {
  const postDominators = computePostDominatorTree(fn, {
    includeThrowsAsExitNode: false,
  });
  const postDominatorFrontierCache = new Map<BlockId, Set<BlockId>>();

  function isControlledBlock(id: BlockId): boolean {
    let controlBlocks = postDominatorFrontierCache.get(id);
    if (controlBlocks === undefined) {
      controlBlocks = postDominatorFrontier(fn, postDominators, id);
      postDominatorFrontierCache.set(id, controlBlocks);
    }
    for (const blockId of controlBlocks) {
      const controlBlock = fn.body.blocks.get(blockId)!;
      switch (controlBlock.terminal.kind) {
        case 'if':
        case 'branch': {
          if (isControlVariable(controlBlock.terminal.test)) {
            return true;
          }
          break;
        }
        case 'switch': {
          if (isControlVariable(controlBlock.terminal.test)) {
            return true;
          }
          for (const case_ of controlBlock.terminal.cases) {
            if (case_.test !== null && isControlVariable(case_.test)) {
              return true;
            }
          }
          break;
        }
      }
    }
    return false;
  }

  return isControlledBlock;
}