State of the repository

As of January 2023, this project is no longer being maintained. Many parts of this projects have open-source alternatives that are part of a bigger effort and that are actively maintained:

• llvm-exegesis allows analyzing individual instructions or snippets of assembly code.
• llvm-mca is a CPU pipeline simulation tool.
• uops.info provides detailed performance characteristics and a machine-readable database of x86-64 instructions.

Goal

Google’s EXEgesis project aims to improve code generation in compilers, via:

1. Providing machine-readable lists of instructions for hardware vendors and microarchitectures.
2. Providing tools for debugging the performance of code based on this data.

For a high-level overview of our efforts, see the slides for a tech talk about EXEgesis (July 2017).

We are providing tools to measure instruction latencies and µOps scheduling. We have contributed that part into LLVM as as the llvm-exegesis tool.

Details

This repository provides a set of tools for extracting data about instructions and latencies from canonical sources and converting them into machine-readable form. Some require parsing PDF files; others are more straightforward.

The output data is available in the form of a Protocol Buffer message.

It includes:

• A textual description. e.g. Add with carry imm8 to AL.
• The raw encoding. e.g. 14 ib and equivalent LLVM mnemonic. e.g. ADC8i8

What’s Next

• Intel x86-64 - done

Get Involved

• Issue tracker: https://github.com/google/EXEgesis/issues
• Mailing list: exegesis-discuss@googlegroups.com

We welcome patches – see CONTRIBUTING for more information on how to submit a patch.