RFC: Improving lit's debug output

LLVM Project
52

So I was hoping https://github.com/llvm/llvm-project/pull/65267 would help, but it looks like it was reverted and the current situation is that the lit output is very broken. I’ve been seeing a failure locally on a change I’m working on and the commands no longer print anything even remotely actionable. In test/tools/dxil-dis/opaque-value_as_metadata.ll, we have a run line like so:

; RUN: llc --filetype=obj %s -o - 2>&1 | dxil-dis -o - | FileCheck %s

But lit now prints this without any of the redirects or pipes and also out of order:

Command Output (stderr):
--
+ : 'RUN: at line 1'
+ /Users/bogner/code/llvm.org/build/bin/llc --filetype=obj /Users/bogner/code/llvm.org/llvm/test/tools/dxil-dis/opaque-value_as_metadata.ll -o -
+ /Users/bogner/code/llvm.org/build/bin/FileCheck /Users/bogner/code/llvm.org/llvm/test/tools/dxil-dis/opaque-value_as_metadata.ll
+ /Users/bogner/code/llvm.org/build/bin/dxil-dis -o -
/Users/bogner/code/llvm.org/llvm/test/tools/dxil-dis/opaque-value_as_metadata.ll:25:15: error: CHECK-DAG: expected string not found in input

whereas if I git revert b6bd9d275f78 012d844fb856 3db5db92d746 f254bbf23374 c981c533055e I get the much more actionable:

Script:
--
: 'RUN: at line 1';   /Users/bogner/code/llvm.org/build/bin/llc --filetype=obj /Users/bogner/code/llvm.org/llvm/test/tools/dxil-dis/opaque-value_as_metadata.ll -o - 2>&1 | /Users/bogner/code/llvm.org/build/bin/dxil-dis -o - | /Users/bogner/code/llvm.org/build/bin/FileCheck /Users/bogner/code/llvm.org/llvm/test/tools/dxil-dis/opaque-value_as_metadata.ll

Should we just revert all of these changes until they can be done without significant regressions?