Function replaceOps

packages/utils/src/script.ts:276–423

(
  script: Script,
  locationData: FullLocationData,
  logs: LogEntry[],
  requires: RequireStatement[],
  sourceTags: SourceTagEntry[],
  constructorParamLength: number,
  optimisations: string[][],
)

}

function replaceOps(
  script: Script,
  locationData: FullLocationData,
  logs: LogEntry[],
  requires: RequireStatement[],
  sourceTags: SourceTagEntry[],
  constructorParamLength: number,
  optimisations: string[][],
): ReplaceOpsResult {
  let asm = scriptToAsm(script);
  let newLocationData = [...locationData];
  let newLogs = [...logs];
  let newRequires = [...requires];
  let newSourceTags = [...sourceTags];

  optimisations.forEach(([pattern, replacement]) => {
    let processedAsm = '';
    let asmToSearch = asm;

    // We add a space or end of string to the end of the pattern to ensure that we match the whole pattern
    // (no partial matches)
    const regex = new RegExp(`${pattern}(\\s|$)`, 'g');

    let matchIndex = asmToSearch.search(regex);
    while (matchIndex !== -1) {
      // We add the part before the match to the processed asm
      processedAsm = mergeAsm(processedAsm, asmToSearch.slice(0, matchIndex));

      // We count the number of spaces in the processed asm + 1, which is equal to the script index
      // We do the same thing to calculate the number of opcodes in the pattern and replacement
      const scriptIndex = processedAsm === '' ? 0 : [...processedAsm.matchAll(/\s+/g)].length + 1;
      const patternLength = [...pattern.matchAll(/\s+/g)].length + 1;
      const replacementLength = replacement === '' ? 0 : [...replacement.matchAll(/\s+/g)].length + 1;

      // We get the locationData entries for every opcode in the pattern
      const patternLocations = newLocationData.slice(scriptIndex, scriptIndex + patternLength);

      // We get the lowest start location and highest end location of the pattern
      const lowestStart = getLowestStartLocation(patternLocations);
      const highestEnd = getHighestEndLocation(patternLocations);

      // Initially we set the position hint to END if any of the pattern locations have a position hint of END
      // It turned out that this was not the correct approach in the case of OP_NOT OP_IF => OP_NOTIF,
      // because OP_IF and OP_NOTIF are START opcodes, and OP_NOT is an END opcode.
      // After reviewing the entire list of optimisations, we set the position hint to the last location's position hint
      // which we believe to be the correct approach, but it is hard to reason about.
      // We've also consulted with AI (o3-max) to help us reason about this, and it seems to be the correct approach.
      const positionHint = patternLocations.at(-1)?.positionHint ?? PositionHint.START;

      // We merge the lowest start and highest end locations into a single location data entry
      const mergedLocation = {
        location: {
          start: lowestStart.location.start,
          end: highestEnd.location.end,
        },
        positionHint,
      };