Changes to the dispacther to support dispacthing based on dpctl device_context

[diptorupd]

Numba-dppy includes changes to Numba (IntelPython/numba#96) to support dispatching of functions based on dpctl.device_context.

After discussions with Numba upstream developers, they have proposed adding a new way inside Numba to support our changes: numba/numba#6770. Quoting Siu Kwan Lam:

This patch will allow one to insert code to switch the options for @jit. I'm also considering an alternative at numba/numba#6770 (comment), which is more flexible by allowing a function to be injected to transform the original dispatcher to something else.

• Evaluate Siu's PR and build it locally on our systems
• Provide review to Siu
• Adapt the changes in Patch for with context numba#96 to use the new design.
• Finalize changes and merge into numba-dppy (Use Numba dispatcher stack for implementing device context #278)

[PokhodenkoSA]

Pushed branches to IntelPython/numba:
Solution:

• https://github.com/IntelPython/numba/tree/wip/dispstack - branch from Siu
• https://github.com/IntelPython/numba/tree/wip/dispstack-patched - with all our patches applied except for IntelPython/numba@6c70fc9

Alternative solution:

• https://github.com/IntelPython/numba/tree/wip/dispstack_alt1 - branch from Siu
• https://github.com/IntelPython/numba/tree/wip/dispstack_alt1-patched - with all our patches applied except for IntelPython/numba@6c70fc9

Comparing solutions:

• sklam/numba@wip/dispstack...sklam:wip/dispstack_alt1

Solutions:

• Support changing dispatcher options via a with context numba/numba#6770 - old solution - draft, deprecated
  • https://github.com/IntelPython/numba/tree/wip/dispstack - branch
  • https://gist.github.com/sklam/b0f145584107f5fbd346eb1a805ec29a - example
• Add support for dispatcher retargeting using with-context numba/numba#6870 - new solution - draft
  • https://github.com/IntelPython/numba/tree/wip/dispstack_alt1 - branch
  • https://gist.github.com/sklam/1eb89424dda59c8c4a7cb1f1ed2385be - example
• sklam/numba@98d916f - unspecified target
  • https://github.com/sklam/numba/compare/wip/target_unspecified - branch
  • https://gist.github.com/sklam/e473b3731759bd360ad17710f388643a - example
• https://github.com/sklam/numba/blob/demo/extendtarget_demo_1/demo.md - demo
  • https://github.com/sklam/numba/tree/demo/extendtarget_demo_1 - branch
  • Improving context stack numba/numba#6814 - merged to 0.54 - compilation flags propagation
  • Glue wrappers to create @overload from split typing and lowering. numba/numba#6762 - merged to 0.54 - Improving context stack numba/numba#6814 based on it
• Add doc for recent target extension features numba/numba#6877 - documentation

Ours:

• https://gitlab.devtools.intel.com/mlp-python/documents/language-implementation-proposal/-/blob/master/Implementation.md - initial proposal for implementing with context
• Use Numba dispatcher stack for implementing device context #278 - initial adoption for Add support for dispatcher retargeting using with-context numba/numba#6870

ToDo:

• Create branch with all numba PRs merged and with our patches merged (excluding Patch for with context numba#96)
  • https://github.com/sklam/numba/tree/demo/extendtarget_demo_1 contains all code merged. We need only apply our unupstreamed patches on top of it.
  • https://github.com/IntelPython/numba/tree/demo/extendtarget_demo_1-patched - contains demo/extendtarget_demo_1 and our patches
• Get llvmlite 0.37 -c numba/label/dev
• Find a way to test numba-dppy in CI with this custom numba version.
  • Make all changes Siu created into a new patch to release0.53-patched
    • Not possible as there are many merge conflicts when apply 6814 on top of release0.53-patched
  • So we can test it only on Numba0.54. No CI. No proof that numba-dppy will be ready to 0.54.
  • Create release0.54-patched (from release0.54 if exists with our patches) and configure CI for it
    • llvmlite 0.37 is not available in out CI.
• Push to numba patch we initially have for with context - Patch for support numba-dppy with device_context numba/numba#6899

[reazulhoque]

The device context was enabled in this PR: #493