JIT Compilation

SkillDev tools

Expert skill for just-in-time compilation including profiling, tiered compilation, and deoptimization

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Then ask your AI: use the JIT Compilation skill

What this skill tells your AI

The instructions your AI receives, as published by a5c-ai/babysitter in library/specializations/programming-languages/skills/jit-compilation/SKILL.md and read by ahel’s review.

Overview

Expert skill for just-in-time compilation including profiling, tiered compilation, and deoptimization.

Capabilities

Implement execution profiling and hot path detection
Design tiered compilation strategies (baseline + optimizing)
Implement on-stack replacement (OSR)
Implement speculative optimizations with guards
Design deoptimization frame reconstruction
Implement inline caching and type feedback
Design code cache management and eviction
Implement method inlining heuristics

Target Processes

jit-compiler-development.js
bytecode-vm-implementation.js
interpreter-implementation.js

Dependencies

V8/HotSpot architecture references

Usage Guidelines

Tiered Approach: Start with a baseline tier, add optimizing tier when profiling data is available
Profile-Guided: Use profiling data to guide optimization decisions
Speculation: Implement guards for speculative optimizations with clean deoptimization
OSR: Implement OSR for long-running loops to benefit from optimization mid-execution
Code Cache: Implement code cache management to handle memory pressure

Output Schema

{
  "type": "object",
  "properties": {
    "tiers": {
      "type": "array",
      "items": {
        "type": "object",
        "properties": {
          "name": { "type": "string" },
          "trigger": { "type": "string" }
        }
      }
    },
    "profilingMethod": {
      "type": "string",
      "enum": ["counters", "sampling", "tracing"]
    },
    "osrSupport": { "type": "boolean" },
    "generatedFiles": {
      "type": "array",
      "items": { "type": "string" }
    }
  }
}

Signals

GitHub stars: 2k
Forks: 112
Last commit: Sep 2026

Advanced

Item type: skill
Key: jit-compilation
Source: github.com/a5c-ai/babysitter

github.com/a5c-ai/babysitter