xcode-compilation-analyzerlisted

# Xcode Compilation Analyzer Use this skill when compile time, not just general project configuration, looks like the bottleneck. ## Core Rules - Start from evidence, ideally a recent `.build-benchmark/` artifact or raw timing-summary output. - Prefer analysis-only compiler flags over persistent project edits during investigation. - Rank findings by expected **wall-clock** impact, not cumulative compile-time impact. When compile tasks are heavily parallelized (sum of compile categories >> wall-clock median), note that fixing individual hotspots may improve parallel efficiency without reducing build wait time. - When the evidence points to parallelized work rather than serial bottlenecks, label recommendations as "Reduces compiler workload (parallel)" rather than "Reduces build time." - Do not edit source or build settings without explicit developer approval. ## What To Inspect - `Build Timing Summary` output from clean and incremental builds - long-running `CompileSwiftSources` or per-file compilation tasks - `SwiftEmitModule` time -- can reach 60s+ after a single-line change in large modules; if it dominates incremental builds, the module is likely too large or macro-heavy - `Planning Swift module` time -- if this category is disproportionately large in incremental builds (up to 30s per module), it signals unexpected input invalidation or macro-related rebuild cascading - ad hoc runs with: - `-Xfrontend -warn-long-expression-type-checking=<ms>` - `-Xfrontend -warn-l