[llvm] [utils] Add script to generate elaborated IR and assembly tests (PR #89026)

[Fangrui Song via llvm-commits]

MaskRay wrote:

> It looks like [lab.llvm.org/buildbot/#/builders/67](https://lab.llvm.org/buildbot/#/builders/67) has been failing for a long time due to this?
> 
> ```
> # .---command stderr------------
> # | /home/buildbot/as-worker-92/clang-with-thin-lto-ubuntu/llvm-project/llvm/test/tools/UpdateTestChecks/update_test_body/gen-fail.test:3:10: error: CHECK: expected string not found in input
> # | # CHECK: log
> # |          ^
> # | <stdin>:1:1: note: scanning from here
> # | Traceback (most recent call last):
> # | ^
> # | <stdin>:1:12: note: possible intended match here
> # | Traceback (most recent call last):
> # |            ^
> # | 
> # | Input file: <stdin>
> # | Check file: /home/buildbot/as-worker-92/clang-with-thin-lto-ubuntu/llvm-project/llvm/test/tools/UpdateTestChecks/update_test_body/gen-fail.test
> # | 
> # | -dump-input=help explains the following input dump.
> # | 
> # | Input was:
> # | <<<<<<
> # |            1: Traceback (most recent call last): 
> # | check:3'0     X~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ error: no match found
> # | check:3'1                ?                        possible intended match
> # |            2:  File "/home/buildbot/as-worker-92/clang-with-thin-lto-ubuntu/llvm-project/llvm/utils/update_test_body.py", line 108, in <module> 
> # | check:3'0     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> # |            3:  retcode = process(args, path) 
> # | check:3'0     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> # |            4:  File "/home/buildbot/as-worker-92/clang-with-thin-lto-ubuntu/llvm-project/llvm/utils/update_test_body.py", line 61, in process 
> # | check:3'0     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> # |            5:  check=True, 
> # | check:3'0     ~~~~~~~~~~~~~
> # |            6:  File "/usr/lib/python3.6/subprocess.py", line 423, in run 
> # | check:3'0     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> # |            .
> # |            .
> # |            .
> # | >>>>>>
> # `-----------------------------
> # error: command failed with exit status: 1
> ```
> 
> Unfortunately the backtrace cuts off before we get to the interesting part.

Just saw this. https://lab.llvm.org/buildbot/#/builders/67 is green now. Perhaps some packages have been upgraded.

https://github.com/llvm/llvm-project/pull/89026