Fast JIT Code Generation for x86-64

by Viktor for The LLVM Compiler Infrastructure

Goal of this project is to implement a fast path through code generation for x86-64 that produces unoptimized code in a very short time. The codegen bypasses the more expensive backend passes altogether by directly emitting machine code that was prepared leveraging the existing TableGen instruction descriptions. This codegen will be useful for fast first-time compilation in an adaptive compilation scheme. The LLVM JIT benefits through an expected increase in speed while remaining portable.