4 ms·

Llvmcpy – Python bindings for LLVM auto-generated from the LLVM-C API

60 points by aleclm 10y ago

bmh100 10y ago
Please forgive my ignorance, but how would this be useful? I am not familiar with compilers or what having bindings in Python to a compiler would help.
- thomaslee 10y ago
  You could, for example, write a compiler in Python that generated native code (or LLVM bitcode to be passed to llc or whatever) via the LLVM API. Writing a compiler in Python vs. C/C++ would be a lot easier in a number of ways. I'm not aware of any "production grade" compilers that do this, but no hard reason why not, I guess. Seems like it'd be nice for prototyping etc. if nothing else.
  - Tempest1981 10y ago
    More on what Thomas said: http://www.llvmpy.org/ http://www.llvmpy.org/
    - bootload 10y ago
      "This project has been deprecated and is no longer being actively developed. We strongly suggest migrating to llvmlite. " try http://llvmlite.pydata.org/en/latest/ http://llvmlite.pydata.org/en/latest/ explanation why http://llvmlite.pydata.org/en/latest/intro/index.html http://llvmlite.pydata.org/en/latest/intro/index.html
  - grej 10y ago
    Check out numba. It does this for a subset of Python.
  - bmh100 10y ago
    So could I use this to conveniently optimize frequently called or inner loop functions?
- m_mueller 10y ago
  Want to make an obscure (your own?) language faster or extend it for your usecase? Write a frontend in python and let llvm do the hard parts.
- exDM69 10y ago
  Two big use cases are building your own compiler in Python and doing some JIT compilation (E.g. regex matcher or similar) to gain some perf. LLVM is fantastic but not everyone wants or can use C++ in their project. I've been doing prototype compilers in Haskell, but Python might also be a nice choice.
yjftsjthsd-h 10y ago
Didn't see in the readme: why "final"? I could see it being considered complete or failed, but it's unclear.
- connerbryan 10y ago
  I believe it's because llvmlite is now suggested. The llvmpy page mentions: > Warning > This project has been deprecated and is no longer being actively developed. We strongly suggest migrating to llvmlite. http://llvmlite.pydata.org/en/latest/ http://llvmlite.pydata.org/en/latest/
  - jholman 10y ago
    Why is this relevant? Are llvmpy and llvmcpy related?
    - connerbryan 10y ago
      Oh, my bad. You're right, I got my links mixed up. aleclm has responded with the correct answer, ignore mine.
- aleclm 10y ago
  Final in the sense that hopefully we won't need a fourth one. It should provide the best performance (since the IR is not re-encoded in Python) and I've tried to make it flexible and future proof. llvmlite currently only supports LLVM 3.8, while I quickly tested llvmcpy with 3.4, 3.8 and 3.9 and works flawlessly. Still quite alpha, though.
witty_username 10y ago
How does this compare to llvmlite? Is this going to support a larger portion of the LLVM API?
- eliben 10y ago
  It looks to be a less complete solution, since it only relies on the LLVM C API which is incomplete. llvmlite digs into the C++ API as well, so while it has more work to do to keep up with changes in LLVM, it's more more feature-complete
  - aleclm 10y ago
    The LLVM-C API is quite powerful, and I'm planning to upstream some patch to expose additional stuff. On the other hand, llvmlite doesn't even parse existing IR, it's basically write-only. Plus, representing the IR in Python makes it less memory efficient than using the native representation.

60 points by aleclm 10y ago

Please forgive my ignorance, but how would this be useful? I am not familiar with compilers or what having bindings in Python to a compiler would help.

thomaslee 10y ago
You could, for example, write a compiler in Python that generated native code (or LLVM bitcode to be passed to llc or whatever) via the LLVM API. Writing a compiler in Python vs. C/C++ would be a lot easier in a number of ways. I'm not aware of any "production grade" compilers that do this, but no hard reason why not, I guess. Seems like it'd be nice for prototyping etc. if nothing else.
- Tempest1981 10y ago
  More on what Thomas said: http://www.llvmpy.org/ http://www.llvmpy.org/
  - bootload 10y ago
    "This project has been deprecated and is no longer being actively developed. We strongly suggest migrating to llvmlite. " try http://llvmlite.pydata.org/en/latest/ http://llvmlite.pydata.org/en/latest/ explanation why http://llvmlite.pydata.org/en/latest/intro/index.html http://llvmlite.pydata.org/en/latest/intro/index.html
- grej 10y ago
  Check out numba. It does this for a subset of Python.
- bmh100 10y ago
  So could I use this to conveniently optimize frequently called or inner loop functions?
m_mueller 10y ago
Want to make an obscure (your own?) language faster or extend it for your usecase? Write a frontend in python and let llvm do the hard parts.
exDM69 10y ago
Two big use cases are building your own compiler in Python and doing some JIT compilation (E.g. regex matcher or similar) to gain some perf. LLVM is fantastic but not everyone wants or can use C++ in their project. I've been doing prototype compilers in Haskell, but Python might also be a nice choice.

yjftsjthsd-h 10y ago

Didn't see in the readme: why "final"? I could see it being considered complete or failed, but it's unclear.

connerbryan 10y ago
I believe it's because llvmlite is now suggested. The llvmpy page mentions: > Warning > This project has been deprecated and is no longer being actively developed. We strongly suggest migrating to llvmlite. http://llvmlite.pydata.org/en/latest/ http://llvmlite.pydata.org/en/latest/
- jholman 10y ago
  Why is this relevant? Are llvmpy and llvmcpy related?
  - connerbryan 10y ago
    Oh, my bad. You're right, I got my links mixed up. aleclm has responded with the correct answer, ignore mine.
aleclm 10y ago
Final in the sense that hopefully we won't need a fourth one. It should provide the best performance (since the IR is not re-encoded in Python) and I've tried to make it flexible and future proof. llvmlite currently only supports LLVM 3.8, while I quickly tested llvmcpy with 3.4, 3.8 and 3.9 and works flawlessly. Still quite alpha, though.

witty_username 10y ago

How does this compare to llvmlite? Is this going to support a larger portion of the LLVM API?

eliben 10y ago
It looks to be a less complete solution, since it only relies on the LLVM C API which is incomplete. llvmlite digs into the C++ API as well, so while it has more work to do to keep up with changes in LLVM, it's more more feature-complete
- aleclm 10y ago
  The LLVM-C API is quite powerful, and I'm planning to upstream some patch to expose additional stuff. On the other hand, llvmlite doesn't even parse existing IR, it's basically write-only. Plus, representing the IR in Python makes it less memory efficient than using the native representation.