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phate / jlm

GNU Lesser General Public License v2.1
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JLM: A research compiler based on the RVSDG IR

Jlm is an experimental compiler/optimizer that consumes and produces LLVM IR. It uses the Regionalized Value State Dependence Graph (RVSDG) as intermediate representation for optimizations.

Dependencies

HLS dependencies

MLIR backend and frontend dependencies

Optional dependencies

Bootstrap

./configure.sh
make all

This presumes that the reight version of llvm-config can be found in $PATH. If that is not the case, you may need to explicitly configure it:

./configure.sh --llvm-config /path/to/llvm-config
make all

For working on the code, it is advisable to initialize header file dependency tracking to ensure that dependent objects get recompiled when header files are changed:

make depend

Additional information about supported build options is available via ./configure.sh --help. Useful options include specifying --target debug to switch to a debug build target instead of the (default) release target.

Documentation

Invoke the following command to generate the doxygen documentation:

make docs

The documentation can then be found at docs/html/index.html

Tests

To run unit tests and jlc C compilation tests, execute

make check

The tests can also be run instrumented under valgrind to validate absence of detectable memory errors:

make valgrind-check

Lastly, when the build has been configured with coverage support (specifying --enable-coverage configure flag for the build), then following build target will compute unit test coverage for all files:

make coverage

The report will be available in build/coverage/coverage.html.

To ensure that all build information in the makefiles are correct, it is also advisable to check that all headers used are declared (this is quite easy to forget). To do this, you can run:

make check-headers

High-level synthesis (HLS) backend

The HLS backend uses the MLIR FIRRTL dialect from CIRCT to convert llvm IR to FIRRTL code.

A compatible installation of CIRCT is needed to compile jlm with the capability to generate FIRRTL and the build has to be configured accordingly. A change of build configuration may require cleaning stale intermediate files first, i.e., run 'make clean'. CIRCT and the HLS backend can be setup with the following commands:

./scripts/build-circt.sh

./configure --enable-hls

MLIR backend

The MLIR backend uses the MLIR RVSDG dialect.

A compatible installation of the MLIR RVSDG dialect is needed to compile jlm with the MLIR backend enabled, and the build has to be configured accordingly. A change of build configuration may require cleaning stale intermediate files first, i.e., run 'make clean'. The MLIR RVSDG dialect and the MLIR backend can be setup with the following commands:

./scripts/build-mlir.sh

./configure --enable-mlir

Publications

An introduction to the RVSDG and the optimizations supported by jlm can be found in the following articles:

N. Reissmann, J. C. Meyer, H. Bahmann, and M. Själander "RVSDG: An Intermediate Representation for Optimizing Compilers" ACM Transactions on Embedded Computing Systems (TECS), vol. 19, no. 6, Dec. 2020. https://dl.acm.org/doi/abs/10.1145/3391902

H. Bahmann, N. Reissmann, M. Jahre, and J. C. Meyer "Perfect Reconstructability of Control Flow from Demand Dependence Graphs" ACM Transactions on Architecture and Code Optimization (TACO), no. 66, Jan. 2015. https://dl.acm.org/doi/10.1145/2693261

N. Reissmann, J. C. Meyer, and M. Själander "RVSDG: An Intermediate Representation for the Multi-Core Era" Nordic Workshop on Multi-Core Computing (MCC), Nov. 2018. https://www.sjalander.com/research/pdf/sjalander-mcc2018.pdf