README

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XLA (Accelerated Linear Algebra) is a domain-specific compiler for linear algebra that optimizes TensorFlow computations. See the documentation.

This directory is currently migrating to OpenXLA and will be the root of the openxla/xla repository.

Where to start? If you're newly integrating with XLA, use PJRT. Integrate with the plugin you need at xla/pjrt/plugin/.

Making a new hardware accelerator type compiler? Create a new PJRT Plugin and follow the examples in xla/pjrt/plugin/example_plugin.

== Directory Structure ==

We're currently re-organizing the directory structure, the end result should be that no sources are directly present at the top-level. Here is the current plan for the directory layout:

• backends/ (created from directories under xla/service)
  • cpu/
  • gpu/
  • interpreter/
  • ...
• hlo/ (created from xla/service/ mostly, no sources expected directly here)
  • client/ (created from xla/client)
  • evaluator/ (created from the relevant files in xla/service)
  • experimental/ (created from xla/experimental)
  • ir/ (created from the relevant files in xla/service)
  • python/ (created from xla/python)
  • tests/ (created from xla/tests)
  • transforms/ (created from the relevant files in xla/service)
  • utils/ (created from the relevant files in xla/service)
• mlir/ (also exported as the root of https://github.com/tensorflow/mlir-hlo and building with CMake)
  • CMakeLists.txt (just like now for mlir-hlo repo).
  • backends/ (same as xla/backends/ but for the MLIR specific bits: this is a short-term solution pending more convergence / XLA Next)
    • cpu
    • gpu (populated from /compiler/xla/mlir/transforms/gpu/passes.td, will contain all the glue for e2e GPU compilation)
  • bindings/
    • c/ (bootstrapped from mlir/hlo/{include,lib}/mlir-hlo-c)
    • python/ (bootstrapped from mlir/hlo/python, should talk about some low-level LAX?)
  • integration_tests/ (to be defined / refined)
  • tools/ (fuzzer, ir-reducer, interpreter/evaluator)
  • transforms/ (generic / cross dialect transforms)
  • utils/
• tsl/ (Tensor Standard Libraries - common utilities for implementing XLA)
• // below are dialects and transforms folders
  • framework/ (moved from compiler/mlir/xla/ir/xla_framework_ops.td)
  • gml_st
    • gmlst-opt.cc
    • gmlst-runner.cc (runner tool that can execute IR at ~gmlst level)
    • ir/
    • integration_test (tests that run things: Tensor(s) in -> Tensor(s) out)
    • test (IR -> IR tests for passes interaction)
    • transforms/
      • bufferize_tiled_loop/
        • bufferize_tiled_loop.cc
        • bufferize_tiled_loop.h
      • ...
  • mhlo/
    • mhlo-opt.cc
    • analysis/
      • dataflow/
        • dataflow.h
        • dataflow.cc
        • test_pass.cc // test_only target, linked into opt tool for testing only.
    • integration_test (tests that run things: Tensor(s) in -> Tensor(s) out)
    • ir/ (dialect definition)
    • test (IR -> IR tests for passes interaction)
    • transforms/
      • materialize_broadcasts/
        • materialize_broadcasts.cc
        • materialize_broadcasts.h // headers stays with the source
        • broadcast_analysis.{cc, h} // private analysis/utils needed for this pass
        • test/ (.mlir unit-tests are collocated with the pass itself).
      • …
      • passes.td // enables group registration for all passes.
    • utils/
  • thlo/
  • runtime/
• pjrt/ (created from xla/pjrt)
  • plugin/ - Public PJRT API entry points for various backends.
• rpc/ (created from xla/rpc)
• runtime/
• stream_executor/ (moved from TensorFlow)
• third_party/ (vendoring of TSL base library)
• tools/ (created from mlir/hlo/tools and xla/tools)
• translate/ (StableHLO to MHLO, MHLO to HLO, HLO to MHLO, MHLO to TOSA)