add new options for ghc 9.12

[geekosaur]

ghc 9.12 adds several new command line options, divided between
LANGUAGEs (already added), warnings, new preprocessor control options,
and compilation control options. Two options needed to be added to the
list of options requiring Int parameters.

The new options, excluding warning and language options, are:

• -fexpose-overloaded-unfoldings
• -fmax-forced-spec-args=N
• -fno-expose-overloaded-unfoldings
• -fno-object-determinism
• -fobject-determinism
• -fwrite-if-compression=N
• -optCmmP…
• -optJSP…
• -pgmCmmP
• -pgmJSP

As they all affect compilation and store hashes, the only necessary
change was to list the two numeric options so they will be parsed
correctly. To the best of our understanding, -pgm* and -opt*
options are already handled as a group.

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[geekosaur]

Does anyone know if I need to add special parsing somewhere for -pgmJSP, -optJSP, etc. somewhere? I believe we parse ghc-options contents to determine recompilation necessity and compute hashes?

[geekosaur]

Okay, already need another change, -fwrite-if-compression both changes the store (although supposedly not the meaning) and takes a numeric arg.

[geekosaur]

I suppose I won't hear anything until Monday at earliest, but with a little more understanding on my side: do we care about the new -pgmJSP and -optJSP… options? I know we support GHCJS, but I'm not sure we do anything with the new JS backend and at this point I don't see any way to support those options even as far as hashing them without a pretty major API break. That said, I also don't see what supporting them would do without some even more major changes to the build logic.

[Mikolaj]

Do any of these options look like they'd require recompilation? IIRC cabal needs to recognize those and recompile all components, not just depend on GHC managing recompilation.

[Mikolaj]

Oh, you said "non-compile-affecting" in the ticket title. :) However, e.g., -fexpose-overloaded-unfoldings affects compilation, so I'm confused.

[geekosaur]

I didn't see anywhere where those went, so I assumed all options are considered to affect compilation unless specified otherwise? This is why I asked for input, and why it's still draft.

---

ETA: @alt-romes confirmed my understanding.

[geekosaur]

Per the most recent Cabal meeting (2024-10-24) this is ready to go now.

[geekosaur]

@mergify backport 3.14

[mergify]

backport 3.14

✅ Backports have been created

• #10479 Backport #10468: add new options for ghc 9.12 has been created for branch 3.14