Driver Class — react Architecture

Source Code

compiler/packages/babel-plugin-react-compiler/src/ReactiveScopes/BuildReactiveFunction.ts lines 59–1245

class Driver {
  cx: Context;

  constructor(cx: Context) {
    this.cx = cx;
  }

  /*
   * Wraps a continuation result with preceding instructions. If there are no
   * instructions, returns the continuation as-is. Otherwise, wraps the continuation's
   * value in a SequenceExpression with the instructions prepended.
   */
  wrapWithSequence(
    instructions: Array<ReactiveInstruction>,
    continuation: {
      block: BlockId;
      value: ReactiveValue;
      place: Place;
      id: InstructionId;
    },
    loc: SourceLocation,
  ): {block: BlockId; value: ReactiveValue; place: Place; id: InstructionId} {
    if (instructions.length === 0) {
      return continuation;
    }
    const sequence: ReactiveSequenceValue = {
      kind: 'SequenceExpression',
      instructions,
      id: continuation.id,
      value: continuation.value,
      loc,
    };
    return {
      block: continuation.block,
      value: sequence,
      place: continuation.place,
      id: continuation.id,
    };
  }

  /*
   * Extracts the result value from instructions at the end of a value block.
   * Value blocks generally end in a StoreLocal to assign the value of the
   * expression. These StoreLocal instructions can be pruned since we represent
   * value blocks as compound values in ReactiveFunction (no phis). However,
   * it's also possible to have a value block that ends in an AssignmentExpression,
   * which we need to keep. So we only prune StoreLocal for temporaries.
   */
  extractValueBlockResult(
    instructions: BasicBlock['instructions'],
    blockId: BlockId,
    loc: SourceLocation,
  ): {block: BlockId; place: Place; value: ReactiveValue; id: InstructionId} {
    CompilerError.invariant(instructions.length !== 0, {
      reason: `Expected non-empty instructions in extractValueBlockResult`,
      description: null,
      loc,
    });
    const instr = instructions.at(-1)!;
    let place: Place = instr.lvalue;
    let value: ReactiveValue = instr.value;
    if (
      value.kind === 'StoreLocal' &&
      value.lvalue.place.identifier.name === null
    ) {
      place = value.lvalue.place;
      value = {
        kind: 'LoadLocal',
        place: value.value,
        loc: value.value.loc,
      };
    }
    if (instructions.length === 1) {
      return {block: blockId, place, value, id: instr.id};
    }
    const sequence: ReactiveSequenceValue = {
      kind: 'SequenceExpression',
      instructions: instructions.slice(0, -1),
      id: instr.id,
      value,
      loc,