LLVM backend resources

Official LLVM backend guide: https://llvm.org/docs/WritingAnLLVMBackend.html

Slides on Selection DAG: https://llvm.org/devmtg/2024-10/slides/tutorial/MacLean-Fargnoli-ABeginnersGuide-to-SelectionDAG.pdf

Slides on building an LLVM Backend, has all the basics. https://llvm.org/devmtg/2014-04/PDFs/Talks/Building%20an%20LLVM%20backend.pdf

A guide just like this one. https://sourcecodeartisan.com/2020/09/13/llvm-backend-0.html

Detailed guide https://jonathan2251.github.io/lbd/TutorialLLVMBackendCpu0.pdf The ebook version: https://jonathan2251.github.io/lbt/index.html

From this llvm thread

“Lessons in TableGen” FOSDEM 2019; Nicolai Hähnle https://fosdem.org/2019/schedule/event/llvm_tablegen/ Slides: https://archive.fosdem.org/2019/schedule/event/llvm_tablegen/attachments/slides/3304/export/events/attachments/llvm_tablegen/slides/3304/tablegen.pdf

Series:

• What has TableGen ever done for us?: http://nhaehnle.blogspot.com/2018/02/tablegen-1-what-has-tablegen-ever-done.html
• Functional Programming: http://nhaehnle.blogspot.com/2018/02/tablegen-2-functional-programming.html
• Bits: http://nhaehnle.blogspot.com/2018/02/tablegen-3-bits.html
• Resolving variables: http://nhaehnle.blogspot.com/2018/03/tablegen-4-resolving-variables.html
• DAGs: http://nhaehnle.blogspot.com/2018/03/tablegen-5-dags.html

Some of the parts of TableGen used in SelectionDAG are in the backend docs (e.g., the keywords OP asked about): https://llvm.org/docs/WritingAnLLVMBackend.html#instruction-set & https://llvm.org/docs/WritingAnLLVMBackend.html#instruction-selector (has a simple example of PatFrag for store).

There are a few examples of simple .td files an LLVM backend in the following:

LLVM backend development by example (RISC-V) 2018 LLVM Developers’ Meeting; Alex Bradbury https://www.youtube.com/watch?v=AFaIP-dF-RA

2014 - Building an LLVM Backend - LLVM Developer’s Meeting https://llvm.org/devmtg/2014-10/#tutorial1 https://llvm.org/devmtg/2014-10/Slides/Cormack-BuildingAnLLVMBackend.pdf https://llvm.org/devmtg/2014-04/PDFs/Talks/Building%20an%20LLVM%20backend.pdf http://web.archive.org/http://llvm.org/devmtg/2014-10/Videos/Building%20an%20LLVM%20backend-720.mov http://llvm.org/devmtg/2014-10/#tutorial1 http://www.inf.ed.ac.uk/teaching/courses/ct/other/LLVMBackend-2015-03-26_v2.pdf

llvm-leg: LEG Example Backend LEG Example Backend: a simple example LLVM backend for an ARM-like architecture: ‘LEG’. https://github.com/frasercrmck/llvm-leg

Others

Dealing with register hierarchies https://llvm.org/devmtg/2016-11/Slides/Braun-DealingWithRegisterHierarchies.pdf