[llvm-dev] [RFC] Compiled regression tests.

[Hal Finkel via llvm-dev]

On 7/2/20 12:44 AM, Michael Kruse wrote:
> Am Mi., 1. Juli 2020 um 14:36 Uhr schrieb Hal Finkel <hfinkel at anl.gov>:
>> When I teach my compilers class, I tell my students to liberally add the
>> ability to serialize to interpretable text all of their internal data
>> structures. It will seem like extra work at first, but when they're
>> trying to debug things later, it will be really helpful. I think this is
>> a key lesson that I, at least, have learned from LLVM. It makes us all
>> more productive in the end (in part because we often spend much more
>> time debugging our code than writing it in the first place). Firing up
>> an actual debugger is slow and (despite our best efforts) fragile,
>> changing a textual input and running it through something that produces
>> textual output is fast.
> One of the first things I write for my data structure is indeed a dump
> function. However, the output is not stable since I regularly
> change/remove/add information that is dumped depending on whether
> information is relevant, adds too much noise, or found a better
> textual representation of the same thing.


I think that, to a large extent, we're on the same page on this aspect. 
It's a question of reuse and stability. If there's a principled way to 
design an output that will be reused across many tests and can 
reasonably be believed will remain relatively stable, then we should do 
that. If not, then unit tests are better. The question is: do we have so 
many such unit tests that we want a special way to construct them from 
IR files (instead of, I suppose, just having the IR in a string in the 
code)? I don't know.

  -Hal


>
>
> Michael

-- 
Hal Finkel
Lead, Compiler Technology and Programming Languages
Leadership Computing Facility
Argonne National Laboratory