Enable split-dwarf and thin archives when possible. (#11292)

Split-dwarf separates debug info to per-object .dwo files, which reduces
IO throughout the build. It works best with the gdb-index linker feature
(of gold and lld), which links to this debug info (vs embedding) and
also adds an index to speed debugger launch.

Thin archives, which is a feature of GNU AR and llvm-ar on Linux
produces static archives that do not embed object files, instead just
referencing them by path.

While spit-dwarf is aimed at debug configurations, thin archives can
help all builds.

Results:

```
Before:
  Clean build:
    real    7m24.609s
    user    392m31.930s
    sys     18m59.113s
  build dir: 11GiB
  libIREECompiler.so: 1.4GiB
  Trivial relink the compiler:
    real    0m5.336s
    user    0m12.862s
    sys     0m31.818s

After:
  Clean build:
    real    7m38.461s
    user    402m52.180s
    sys     18m8.314s
  build dir: 5.2GiB
  libIREECompiler.so: 490MiB
  Trivial relink the compiler:
    real    0m4.350s
    user    0m8.233s
    sys     0m8.104s
  gdb of iree-compile starts instantly and sets a breakpoint on ireeCompilerRunMain with no delay (a few seconds to step in)
```

For a RelWithDebInfo build as documented on our website, wall clock time
to do a clean build is in the noise on my machine, but with the new
flags:

* Build directory size is reduced by >50%
* Size of the main compiler shared library is reduced by ~65%
* Time to incremental relink of the compiler after a trivial change to a
C file is reduced by ~18%.

Ideally there would be a less invasive way to enable these things, but
that isn't coming any time soon. I think the complexity is worth it. The
trivial relink case shows that this should make the cycle time better
disproportionately on lower end machines as well.
3 files changed
tree: d673962e032122ef08f7335115c2076ce8283dab
  1. .github/
  2. benchmarks/
  3. build_tools/
  4. compiler/
  5. docs/
  6. experimental/
  7. integrations/
  8. llvm-external-projects/
  9. runtime/
  10. samples/
  11. tests/
  12. third_party/
  13. tools/
  14. .bazelignore
  15. .bazelrc
  16. .bazelversion
  17. .clang-format
  18. .dockerignore
  19. .gitignore
  20. .gitmodules
  21. .pylintrc
  22. .style.yapf
  23. .yamllint.yml
  24. AUTHORS
  25. BUILD.bazel
  26. CITATION.cff
  27. CMakeLists.txt
  28. configure_bazel.py
  29. CONTRIBUTING.md
  30. LICENSE
  31. README.md
  32. WORKSPACE
README.md

IREE: Intermediate Representation Execution Environment

IREE (Intermediate Representation Execution Environment, pronounced as “eerie”) is an MLIR-based end-to-end compiler and runtime that lowers Machine Learning (ML) models to a unified IR that scales up to meet the needs of the datacenter and down to satisfy the constraints and special considerations of mobile and edge deployments.

See our website for project details, user guides, and instructions on building from source.

CI Status

Project Status

IREE is still in its early phase. We have settled down on the overarching infrastructure and are actively improving various software components as well as project logistics. It is still quite far from ready for everyday use and is made available without any support at the moment. With that said, we welcome any kind of feedback on any communication channels!

Communication Channels

Related Project Channels

  • MLIR topic within LLVM Discourse: IREE is enabled by and heavily relies on MLIR. IREE sometimes is referred to in certain MLIR discussions. Useful if you are also interested in MLIR evolution.

Architecture Overview

IREE Architecture IREE Architecture

See our website for more information.

Presentations and Talks

  • 2021-06-09: IREE Runtime Design Tech Talk (recording and slides)
  • 2020-08-20: IREE CodeGen: MLIR Open Design Meeting Presentation (recording and slides)
  • 2020-03-18: Interactive HAL IR Walkthrough (recording)
  • 2020-01-31: End-to-end MLIR Workflow in IREE: MLIR Open Design Meeting Presentation (recording and slides)

License

IREE is licensed under the terms of the Apache 2.0 License with LLVM Exceptions. See LICENSE for more information.