handleInstruction() — react Function Reference

Source Code

compiler/packages/babel-plugin-react-compiler/src/HIR/PropagateScopeDependenciesHIR.ts lines 667–745

export function handleInstruction(
  instr: Instruction,
  context: DependencyCollectionContext,
): void {
  const {id, value, lvalue} = instr;
  context.declare(lvalue.identifier, {
    id,
    scope: context.currentScope,
  });
  if (
    context.isDeferredDependency({kind: HIRValue.Instruction, value: instr})
  ) {
    return;
  }
  if (value.kind === 'PropertyLoad') {
    context.visitProperty(value.object, value.property, false);
  } else if (value.kind === 'StoreLocal') {
    context.visitOperand(value.value);
    if (value.lvalue.kind === InstructionKind.Reassign) {
      context.visitReassignment(value.lvalue.place);
    }
    context.declare(value.lvalue.place.identifier, {
      id,
      scope: context.currentScope,
    });
  } else if (value.kind === 'DeclareLocal' || value.kind === 'DeclareContext') {
    /*
     * Some variables may be declared and never initialized. We need to retain
     * (and hoist) these declarations if they are included in a reactive scope.
     * One approach is to simply add all `DeclareLocal`s as scope declarations.
     *
     * Context variables with hoisted declarations only become live after their
     * first assignment. We only declare real DeclareLocal / DeclareContext
     * instructions (not hoisted ones) to avoid generating dependencies on
     * hoisted declarations.
     */
    if (convertHoistedLValueKind(value.lvalue.kind) === null) {
      context.declare(value.lvalue.place.identifier, {
        id,
        scope: context.currentScope,
      });
    }
  } else if (value.kind === 'Destructure') {
    context.visitOperand(value.value);
    for (const place of eachPatternOperand(value.lvalue.pattern)) {
      if (value.lvalue.kind === InstructionKind.Reassign) {
        context.visitReassignment(place);
      }
      context.declare(place.identifier, {
        id,
        scope: context.currentScope,
      });
    }
  } else if (value.kind === 'StoreContext') {
    /**
     * Some StoreContext variables have hoisted declarations. If we're storing
     * to a context variable that hasn't yet been declared, the StoreContext is
     * the declaration.
     * (see corresponding logic in PruneHoistedContext)
     */
    if (
      !context.hasDeclared(value.lvalue.place.identifier) ||
      value.lvalue.kind !== InstructionKind.Reassign
    ) {
      context.declare(value.lvalue.place.identifier, {
        id,
        scope: context.currentScope,
      });
    }

    for (const operand of eachInstructionValueOperand(value)) {
      context.visitOperand(operand);
    }
  } else {
    for (const operand of eachInstructionValueOperand(value)) {
      context.visitOperand(operand);
    }
  }
}