| 1 | /** |
| 2 | * Copyright (c) Meta Platforms, Inc. and affiliates. |
| 3 | * |
| 4 | * This source code is licensed under the MIT license found in the |
| 5 | * LICENSE file in the root directory of this source tree. |
| 6 | */ |
| 7 | |
| 8 | import {CompilerError} from '..'; |
| 9 | import {BlockId, ReactiveFunction, ReactiveTerminalStatement} from '../HIR'; |
| 10 | import {ReactiveFunctionVisitor, visitReactiveFunction} from './visitors'; |
| 11 | |
| 12 | /** |
| 13 | * Assert that all break/continue targets reference existent labels. |
| 14 | */ |
| 15 | export function assertWellFormedBreakTargets(fn: ReactiveFunction): void { |
| 16 | visitReactiveFunction(fn, new Visitor(), new Set()); |
| 17 | } |
| 18 | |
| 19 | class Visitor extends ReactiveFunctionVisitor<Set<BlockId>> { |
| 20 | override visitTerminal( |
| 21 | stmt: ReactiveTerminalStatement, |
| 22 | seenLabels: Set<BlockId>, |
| 23 | ): void { |
| 24 | if (stmt.label != null) { |
| 25 | seenLabels.add(stmt.label.id); |
| 26 | } |
| 27 | const terminal = stmt.terminal; |
| 28 | if (terminal.kind === 'break' || terminal.kind === 'continue') { |
| 29 | CompilerError.invariant(seenLabels.has(terminal.target), { |
| 30 | reason: 'Unexpected break to invalid label', |
| 31 | loc: stmt.terminal.loc, |
| 32 | }); |
| 33 | } |
| 34 | } |
| 35 | } |