Chisel/FIRRTL Hardware Compiler Framework

by lnyan • 5 years ago

59 16 5 years ago

syntaxing• 5 years ago

I think (?) the first generation of TPU and Coral chips were designed using Chisel. There was a good presentation done by Google a while back but I will have to dig for it to find it

ekiwi5• 5 years ago

It was in fact the EdgeTPU (which is different from the TPU used in data centers).

The talk from a google engineer can be found on youtube: https://www.youtube.com/watch?v=x85342Cny8c Please note that they were using a version of Chisel from 5+ years ago and many things have changed since then. It is still true though that Chisel can be hard to learn for typical hardware engineers, which is why it may be best suited for small and highly dedicated teams rather then large hardware companies.

[EDIT] Here is a talk from a solo-developer using the latest version of Chisel: https://www.youtube.com/watch?v=Wst8IoYRWKo

Rochus4• 5 years ago

Some interesting quotes from the presentation:

"frankly, most hardware engineers don't really get passed this yellow [Chisel learning] curve"

"Chisel makes the long pole of chip design longer"

"the productivity gains we might have had on the design side were more than lost on the verification side"

"It might be a hard sell for other projects to adopt Chisel [...] there were a buch of dark periods, mostly".

xvilka• 5 years ago

There was a suggestion[1] (by me) to coordinate more between various hardware design/programming tools to agree on the common intermediate representation. Sadly, nothing came out of it yet.

[1] https://github.com/SymbiFlow/ideas/issues/19

ekiwi5• 5 years ago

Did you see the work being done on CIRCT? https://github.com/llvm/circt

I remember one of the reasons you did not want to use firrtl was that its compiler is implemented in Scala and thus hard to integrate into other projexts. CIRCT will solve that problem by providing a firrtl compiler implemented in C++. Other languages like Verilog/VHDL and new high level languages for HLS-like designs are also on the todo list.

mikeurbach• 5 years ago

I contribute to CIRCT, so I feel like I should chime in here. I personally hope that it can provide exactly the kind of unifying IRs we are all hoping for in the open-source community. The fact that the tools are implemented in C++ may be a win for some, but I think the CIRCT project is compelling for much deeper reasons. The README states the ambition clearly:

By working together, we hope that we can build a new center of gravity to draw contributions from the small (but enthusiastic!) community of people who work on open hardware tooling.

There are weekly community meetings that are open to the public, and we have guest speakers from all sorts of interesting projects in the open-source community. Many of those are leading to collaborations and contributions to CIRCT.

There hasn't been much (any?) discussion of CIRCT on HN, but rather than present the reasons I think it's so great here, I'll point to a talk[1] I gave earlier this year and a much better talk[2] Chris Lattner gave shortly thereafter, both of which lead up to the "Why CIRCT?" question in the second half.

Looking back at that SymbiFlow thread, I see familiar faces that are now actively contributing to CIRCT. There are mentions of many different hardware IRs in some of the posts, but at least three have first-class support in CIRCT today: FIRRTL[3], LLHD[4], and Calyx[5]. This is all very recent and experimental, but I would say the results are already promising.

[1] https://slideslive.com/38955645/applying-circuit-ir-compiler...

[2] https://www.youtube.com/watch?v=4HgShra-KnY

[3] https://circt.llvm.org/docs/Dialects/FIRRTL/

[4] https://circt.llvm.org/docs/Dialects/LLHD/

[5] https://circt.llvm.org/docs/Dialects/Calyx/

Chisel/FIRRTL Hardware Compiler Framework

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