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[AVR] Include AVR by default in LLVM builds

Authored by dylanmckay on Mar 11 2020, 11:07 PM.

Description

[AVR] Include AVR by default in LLVM builds

Summary:
This patch makes the AVR backend an official target of LLVM, serving
as a request for comments for moving the AVR backend out of
experimental.

A future patch will move the LLVM AVR buildbot (llvm-avr-linux) from the
staging buildmaster to the production buildmaster, so error emails will
start to go out.

Summary of the backend

  • 16-bit little endian
  • AsmParser based assembly parser
  • uses the MC library for generating AVR ELFs
  • most logic driven from standard TableGen-erated tables like other backends
  • passes all of the test suite under check-all, including generic CodeGen and DebugInfo tests
  • Used in two frontends
  • Limited, but functional support for DebugInfo and LLVM DWARF dumping
  • Binary compatible with AVR-GCC and avr-{libc,libgcc} for the most part
  • Cannot lower 32-bit shifts due to a bug, can lower shifts larger or smaller
  • Supports assembly/MC for all the entire AVR ISA, generally generates poorly optimized machine instructions, with most focus thus far on correctness

I've added reviewers and subscribers from previous patches where backends were made official,
and those who participated in the recent thread on llvm-dev, please add anybody I've missed.

The most recent discussion on this topic can be found in the llvm-dev thread Moving the AVR backend out of experimental

Reviewers: chandlerc, lattner, rengolin, tstellar, arsenm, thakis, simoll, asb

Reviewed By: rengolin, thakis

Subscribers: CryZe, wdng, mgorny, aprantl, Jim, hans, aykevl, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D75099

Details

Event Timeline

hans added a subscriber: hans.Aug 25 2020, 11:23 AM

Would you like to add a mention of this in docs/ReleaseNotes.rst? Thanks.