[llvm-dev] Migrate utils/ Python 2 scripts to Python 3

[Matthias Braun via llvm-dev]

+1 from my for changing LLVMs minimum requirements (for compiling llvm) to python3 and dropping python2 support.

In case of lit we probably need to keep the code in a way that works with python 2 and 3 though as that will affect various projects outside of core llvm that started adopting it.

- Matthias

> On Jan 29, 2018, at 3:42 PM, Jason Molenda via llvm-dev <llvm-dev at lists.llvm.org> wrote:
> 
> Hi Fangrui, for what it's worth regarding lldb, Zachary Turner has already done a lot of work to make the majority of its python code (most importantly, its testsuite) work with Python 3 as well as Python 2.
> 
> J
> 
>> On Jan 29, 2018, at 12:46 PM, Fāng-ruì Sòng via llvm-dev <llvm-dev at lists.llvm.org> wrote:
>> 
>> Hi LLVM-Devs,
>> 
>> I noticed that many Python scripts under utils/ have a shebang of
>> `#!/usr/bin/python` (which is a symlink to python2.7 on many platforms) and some of them use Python 2 syntax that is not compatible with Python 3 (e.g. print statements; str/bytes)
>> 
>> I created a revision to migrate utils/update_{llc_,}_test_checks.py from Python 2 to Python 3 https://reviews.llvm.org/D42450 , the arguments against making it Python 3 is:
>> 
>> * There are many Mac OS X users and Mac OS X 10.8 comes with Python 2.7 pre-installed [0] but not Python 3.
>> * Forcing scripts to use Python 3 (by doing so we can avoid some compatibility trouble) may not be a good idea.
>> 
>> Python 2.7 was published in 2010 and planned as the last of the 2.x releases. It will not be maintained past 2020 and there is also a retirement page https://pythonclock.org/ .
>> 
>> The second argument would not need to be addressed if the first one did not lay too much burden on developers. After all, we have to install `cmake, ninja/GNU Make / libedit(for lldb)` to build LLVM. These packages are not installed by default on many platforms.
>> 
>> Thoughts on deprecating Python 2 for utils/ scripts (different from libclang or lldb scripts) which are not user-facing?
>> 
>> [0]: https://docs.python.org/3/using/mac.html#getting-and-installing-macpython
>> 
>> 
>> Thanks,
>> Fangrui
>> _______________________________________________
>> LLVM Developers mailing list
>> llvm-dev at lists.llvm.org
>> http://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-dev
> 
> _______________________________________________
> LLVM Developers mailing list
> llvm-dev at lists.llvm.org
> http://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-dev