Steven Johnson

> (have you ever used [direnv](https://direnv.net/)?) Yikes, no, magic hidden things that set env vars based on my location is (to me) an indication of a system gone wrong

> Why do we need to set LLVM_ROOT here? The buildbots have set only LLVM_DIR for ~ever. To be more on point: it seems suboptimal to have to set two...

> cmake --build --preset linux-x64-asan On gLinux, this fails for me with `CMake Error: Could not read presets from /usr/local/google/home/srj/GitHub/Halide/build-asan: File not found`

LGTM

So I'm not entirely sure what's going on, but while trying to debug some of these issues via a JIT test, it looks like our debug runtime isn't (reliably) used...

I know OpenGL is deprecated on OSX, but do we expect it to work at all? On Big Sur, I fail reliably with `Could not load function pointer for glDispatchCompute`....

> I think we might want some kind of warning, but failing aggressively seems like overkill-- there's some 3rd party OpenGL(ES?) implementations available on macOS (see e.g. https://stackoverflow.com/questions/65802625/develop-using-opengl-4-x-on-osx-big-sur) that some...

> `correctness_vector_cast` (intermittently) `performance_async_gpu` (SEGFAULT) `generator_aot_gpu_multi_context_threaded` `generator_aot_msan` On my linux box, I don't get vector_gpu failures, but I do get correctness_math failures.

For `performance_async_gpu`, the crash seems to be because we call `halide_buffer_copy` with a src that has a null host and a null device_interface (which we don't properly check for): ```...

> > but I do get correctness_math failures. > > Can you post the output? I could probably fix it quickly (I had failures in that test, and thought I'd...