evaluatePhi() — react Function Reference

Architecture documentation for the evaluatePhi() function in ConstantPropagation.ts from the react codebase.

Function typescript BabelCompiler Optimization calls 1 called by 1

Entity Profile

BabelCompiler→ Optimization→ evaluatePhi() — react Function Reference

Dependency Diagram

graph TD
  9356843d_f70e_f922_5710_d8bd36a38797["evaluatePhi()"]
  ee83ff7b_e532_0fd6_0eae_7fe885ffe129["ConstantPropagation.ts"]
  9356843d_f70e_f922_5710_d8bd36a38797 -->|defined in| ee83ff7b_e532_0fd6_0eae_7fe885ffe129
  4419ef20_4b5f_b18c_6237_57b76d298666["applyConstantPropagation()"]
  4419ef20_4b5f_b18c_6237_57b76d298666 -->|calls| 9356843d_f70e_f922_5710_d8bd36a38797
  041ca752_10c1_3cda_1f5c_02f44a01310e["invariant()"]
  9356843d_f70e_f922_5710_d8bd36a38797 -->|calls| 041ca752_10c1_3cda_1f5c_02f44a01310e
  style 9356843d_f70e_f922_5710_d8bd36a38797 fill:#6366f1,stroke:#818cf8,color:#fff

Relationship Graph

Source Code

compiler/packages/babel-plugin-react-compiler/src/Optimization/ConstantPropagation.ts lines 168–222

function evaluatePhi(phi: Phi, constants: Constants): Constant | null {
  let value: Constant | null = null;
  for (const [, operand] of phi.operands) {
    const operandValue = constants.get(operand.identifier.id) ?? null;
    // did not find a constant, can't constant propogate
    if (operandValue === null) {
      return null;
    }

    /*
     * first iteration of the loop, let's store the operand and continue
     * looping.
     */
    if (value === null) {
      value = operandValue;
      continue;
    }

    // found different kinds of constants, can't constant propogate
    if (operandValue.kind !== value.kind) {
      return null;
    }

    switch (operandValue.kind) {
      case 'Primitive': {
        CompilerError.invariant(value.kind === 'Primitive', {
          reason: 'value kind expected to be Primitive',
          loc: GeneratedSource,
        });

        // different constant values, can't constant propogate
        if (operandValue.value !== value.value) {
          return null;
        }
        break;
      }
      case 'LoadGlobal': {
        CompilerError.invariant(value.kind === 'LoadGlobal', {
          reason: 'value kind expected to be LoadGlobal',
          loc: GeneratedSource,
        });

        // different global values, can't constant propogate
        if (operandValue.binding.name !== value.binding.name) {
          return null;
        }
        break;
      }
      default:
        return null;
    }
  }

  return value;
}