pruneMaybeThrows() — react Function Reference

Source Code

compiler/packages/babel-plugin-react-compiler/src/Optimization/PruneMaybeThrows.ts lines 38–75

export function pruneMaybeThrows(fn: HIRFunction): void {
  const terminalMapping = pruneMaybeThrowsImpl(fn);
  if (terminalMapping) {
    /*
     * If terminals have changed then blocks may have become newly unreachable.
     * Re-run minification of the graph (incl reordering instruction ids)
     */
    reversePostorderBlocks(fn.body);
    removeUnreachableForUpdates(fn.body);
    removeDeadDoWhileStatements(fn.body);
    removeUnnecessaryTryCatch(fn.body);
    markInstructionIds(fn.body);
    mergeConsecutiveBlocks(fn);

    // Rewrite phi operands to reference the updated predecessor blocks
    for (const [, block] of fn.body.blocks) {
      for (const phi of block.phis) {
        for (const [predecessor, operand] of phi.operands) {
          if (!block.preds.has(predecessor)) {
            const mappedTerminal = terminalMapping.get(predecessor);
            CompilerError.invariant(mappedTerminal != null, {
              reason: `Expected non-existing phi operand's predecessor to have been mapped to a new terminal`,
              description: `Could not find mapping for predecessor bb${predecessor} in block bb${
                block.id
              } for phi ${printPlace(phi.place)}`,
              loc: GeneratedSource,
            });
            phi.operands.delete(predecessor);
            phi.operands.set(mappedTerminal, operand);
          }
        }
      }
    }

    assertConsistentIdentifiers(fn);
    assertTerminalSuccessorsExist(fn);
  }
}