SSABuilder Class — react Architecture

Source Code

compiler/packages/babel-plugin-react-compiler/src/SSA/EnterSSA.ts lines 40–238

class SSABuilder {
  #states: Map<BasicBlock, State> = new Map();
  #current: BasicBlock | null = null;
  unsealedPreds: Map<BasicBlock, number> = new Map();
  #blocks: Map<BlockId, BasicBlock>;
  #env: Environment;
  #unknown: Set<Identifier> = new Set();
  #context: Set<Identifier> = new Set();

  constructor(env: Environment, blocks: ReadonlyMap<BlockId, BasicBlock>) {
    this.#blocks = new Map(blocks);
    this.#env = env;
  }

  get nextSsaId(): IdentifierId {
    return this.#env.nextIdentifierId;
  }

  defineFunction(func: HIRFunction): void {
    for (const [id, block] of func.body.blocks) {
      this.#blocks.set(id, block);
    }
  }

  enter(fn: () => void): void {
    const current = this.#current;
    fn();
    this.#current = current;
  }

  state(): State {
    CompilerError.invariant(this.#current !== null, {
      reason: 'we need to be in a block to access state!',
      loc: GeneratedSource,
    });
    return this.#states.get(this.#current)!;
  }

  makeId(oldId: Identifier): Identifier {
    return {
      id: this.nextSsaId,
      declarationId: oldId.declarationId,
      name: oldId.name,
      mutableRange: {
        start: makeInstructionId(0),
        end: makeInstructionId(0),
      },
      scope: null, // reset along w the mutable range
      type: makeType(),
      loc: oldId.loc,
    };
  }

  defineContext(oldPlace: Place): Place {
    const newPlace = this.definePlace(oldPlace);
    this.#context.add(oldPlace.identifier);
    return newPlace;
  }

  definePlace(oldPlace: Place): Place {
    const oldId = oldPlace.identifier;
    if (this.#unknown.has(oldId)) {
      CompilerError.throwTodo({
        reason: `[hoisting] EnterSSA: Expected identifier to be defined before being used`,
        description: `Identifier ${printIdentifier(oldId)} is undefined`,
        loc: oldPlace.loc,
        suggestions: null,
      });
    }

    // Do not redefine context references.
    if (this.#context.has(oldId)) {
      return this.getPlace(oldPlace);
    }

    const newId = this.makeId(oldId);
    this.state().defs.set(oldId, newId);
    return {
      ...oldPlace,
      identifier: newId,
    };