jit-compilation

name	JIT Compilation
description	Expert skill for just-in-time compilation including profiling, tiered compilation, and deoptimization
category	Runtime Optimization
allowed-tools	["Read","Write","Edit","Glob","Grep","Bash"]
graph	{"domains":["domain:software-engineering"],"specializations":["specialization:programming-languages"],"skillAreas":["skill-area:compiler-implementation","skill-area:profiling-cpu"],"roles":["role:backend-engineer"]}

JIT Compilation Skill

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

1. Tiered Approach: Start with a baseline tier, add optimizing tier when profiling data is available
2. Profile-Guided: Use profiling data to guide optimization decisions
3. Speculation: Implement guards for speculative optimizations with clean deoptimization
4. OSR: Implement OSR for long-running loops to benefit from optimization mid-execution
5. 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",