debugging-instruments

Debug an iOS app crash using LLDB by setting breakpoints and inspecting variables to trace the fault. The Skill guides Swift and Objective-C workflows on simulators and real devices to reproduce the issue and capture structured diagnostic data safely.

Finding memory leaks in an iOS app is best achieved by analyzing the memory graph to detect retain cycles. The Skill provides structured guidance on using the Memory Graph Debugger and Instruments templates like Leaks to pinpoint and resolve memory issues.

Profile main-thread hangs during complex UI interactions by running Instruments time profiling sessions. The Skill offers validated diagnostic steps to identify performance bottlenecks and slow rendering while reproducing the UI interactions in Xcode.

Instruments is not typically used to triage build failures, but the Skill provides specific guidance for build failure triage during CI and local development. It covers validated diagnostic steps for crashes and performance issues across profiling sessions.

Use the Memory Graph Debugger to capture retain cycles and leaks at a specific point in time, while the Allocations template tracks object lifecycle and memory growth over a profiling session. The Skill guides structured analysis using both tools to ensure safe debugging.

This Skill supports debugging iOS apps on real devices and simulators. It provides structured LLDB workflows and tool-specific best practices to ensure safe debugging without altering app behavior across development and profiling sessions.