rewriteSplices() — react Function Reference

Source Code

compiler/packages/babel-plugin-react-compiler/src/Inference/InferEffectDependencies.ts lines 373–490

function rewriteSplices(
  originalBlock: BasicBlock,
  splices: Array<SpliceInfo>,
  rewriteBlocks: Array<BasicBlock>,
): void {
  if (splices.length === 0) {
    return;
  }
  /**
   * Splice instructions or value blocks into the original block.
   * --- original block ---
   * bb_original
   *   instr1
   *   ...
   *   instr2 <-- splice location
   *   instr3
   *   ...
   *   <original terminal>
   *
   * If there is more than one block in the splice, this means that we're
   * splicing in a set of value-blocks of the following structure:
   * --- blocks we're splicing in ---
   * bb_entry:
   *   instrEntry
   *   ...
   *   <splice terminal> fallthrough=bb_exit
   *
   * bb1(value):
   *   ...
   *
   * bb_exit:
   *   instrExit
   *   ...
   *   <synthetic terminal>
   *
   *
   * --- rewritten blocks ---
   * bb_original
   *   instr1
   *   ... (original instructions)
   *   instr2
   *   instrEntry
   *   ... (spliced instructions)
   *   <splice terminal> fallthrough=bb_exit
   *
   * bb1(value):
   *   ...
   *
   * bb_exit:
   *   instrExit
   *   ... (spliced instructions)
   *   instr3
   *   ... (original instructions)
   *   <original terminal>
   */
  const originalInstrs = originalBlock.instructions;
  let currBlock: BasicBlock = {...originalBlock, instructions: []};
  rewriteBlocks.push(currBlock);

  let cursor = 0;

  for (const rewrite of splices) {
    while (originalInstrs[cursor].id < rewrite.location) {
      CompilerError.invariant(
        originalInstrs[cursor].id < originalInstrs[cursor + 1].id,
        {
          reason:
            '[InferEffectDependencies] Internal invariant broken: expected block instructions to be sorted',
          loc: originalInstrs[cursor].loc,
        },
      );
      currBlock.instructions.push(originalInstrs[cursor]);
      cursor++;
    }
    CompilerError.invariant(originalInstrs[cursor].id === rewrite.location, {
      reason:
        '[InferEffectDependencies] Internal invariant broken: splice location not found',
      loc: originalInstrs[cursor].loc,
    });

    if (rewrite.kind === 'instr') {