Xcode compile profiler

Skill Xopoko/build-swift-apps/skills/xcode-compile-profiler

Swift-focused AI agent skills for iOS and macOS: build, debug, simulator, SwiftUI, Xcode, App Store workflows. Part of Plug'n Skills.

Install

npx -y skills add Xopoko/build-swift-apps --skill xcode-compile-profiler

Assembled from the repository path, not quoted from the project. Check it against their README if it does not work.

What its author says it does

Copied from the file, not written here

Analyze Swift and mixed-language compile hotspots from timing summaries, Swift frontend diagnostics, type-checking warnings, CompileSwiftSources, SwiftEmitModule, and related build evidence.

SKILL.md

2.4 KB, as published. Nobody here has run it

Xcode Compile Profiler

Use when compile time, type checking, or mixed-language compilation is the bottleneck. Recommend first; do not edit source or build settings without explicit approval.

Rules

Start from .build-benchmark/ artifacts or raw build timing output.
Prefer ad hoc diagnostic flags over persistent project edits.
Rank by expected wall-clock impact, not cumulative parallel compiler work.
If compile work is parallelized, label improvements as "Reduces compiler workload (parallel)" unless wait time should drop.
Separate code-level, project-level, and module-level recommendations.

Inspect

clean and incremental Build Timing Summary
long CompileSwiftSources, per-file compile tasks, SwiftEmitModule, and Planning Swift module
mixed Swift/Objective-C boundaries, bridging headers, generated Swift-to-ObjC surfaces
diagnostics:
- -Xfrontend -warn-long-expression-type-checking=<ms>
- -Xfrontend -warn-long-function-bodies=<ms>
- -Xfrontend -debug-time-compilation
- -Xfrontend -debug-time-function-bodies
- -Xswiftc -driver-time-compilation
- -Xfrontend -stats-output-dir <path>

Preferred script:

python3 ../../shared/build-optimization/scripts/diagnose_compilation.py \
  --project App.xcodeproj \
  --scheme MyApp \
  --configuration Debug \
  --destination "platform=iOS Simulator,name=<latest available iPhone simulator>,OS=latest" \
  --threshold 100 \
  --output-dir .build-benchmark

Checks

Look first for missing explicit types in expensive expressions, deeply chained expressions, delegates typed as AnyObject, oversized bridging surfaces, unqualified header imports, non-final classes, broad public/open symbols, monolithic SwiftUI body, and closures without helpful type annotations.

Output

For each recommendation include evidence, file/module, expected wait-time impact or parallel-work caveat, confidence, and whether approval is needed. If evidence points to project configuration, read and hand off to xcode-project-auditor.

Resources

references/code-compilation-checks.md
../../shared/build-optimization/references/recommendation-format.md
../../shared/build-optimization/references/build-optimization-sources.md