
Initial patches to add an MC layer for RISC-V - cokernel_hacker
http://llvm.org/viewvc/llvm-project?view=revision&revision=285707
======
rwmj
The author of these patches is giving a talk at the LLVM dev meeting on
Thursday:

[https://groups.google.com/a/groups.riscv.org/d/msg/sw-
dev/Yp...](https://groups.google.com/a/groups.riscv.org/d/msg/sw-
dev/Yp7lbvgg2Cg/9iioB3U2IgAJ)

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wyager
For those confused by the title, it means they're working on adding LLVM
support for RISC-V.

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ZenoArrow
What's an MC layer?

~~~
cokernel_hacker
It is the low-level assembler-related machinery in LLVM.

For more details, see [http://blog.llvm.org/2010/04/intro-to-llvm-mc-
project.html](http://blog.llvm.org/2010/04/intro-to-llvm-mc-project.html)

~~~
ZenoArrow
Thank you. Guessing the MC stands for 'Machine Code' then.

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lpmay
When this is done, does it mean any LLVM language can compile to RISC-V? Or is
there additional per-language work that would need to happen first?

~~~
asb
There'll be some small amount of additional per-language work generally. I
(and lowrisc.org as a whole) would be keen to support people attempting such
ports. Rust and Swift are obviously high on the list.

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CalChris
So they have an LLVM target for RISC-V. They could submit that but they choose
to divide it up into pieces and submit them piecemeal. This is the first piece
of that meal. If you want to skip to the dessert:

[https://github.com/riscv/riscv-llvm](https://github.com/riscv/riscv-llvm)

~~~
legulere
It's actually a reimplementation, because there were some (I think legal)
problems with the implementation that you linked

~~~
CalChris
Thanks. That sounds similar to the GCC kerfuffle.

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phkahler
When will GCC get their RISC-V support? I thought I read the UCB lawyer issue
got resolved. Or is that not so?

~~~
CalChris
RISC-V has GCC support already:

[https://github.com/riscv/riscv-gcc](https://github.com/riscv/riscv-gcc)

But the UCB IP lawyers are preventing it (for now) from getting upstreamed to
GCC proper:

[http://www.phoronix.com/scan.php?page=news_item&px=GCC-
RISCV...](http://www.phoronix.com/scan.php?page=news_item&px=GCC-RISCV-Lawyer-
Hold)

