wasmtime / PR #3402 Remove more old backend ISA concepts · git-wasmtime

Stream: git-wasmtime

Topic: wasmtime / PR #3402 Remove more old backend ISA concepts

Wasmtime GitHub notifications bot (Sep 30 2021 at 23:29):

bnjbvr opened PR #3402 from unify-targetisa-mach-backend to main:

This also paves the way for unifying TargetIsa and MachBackend, since now they map one to one. In theory the two traits could be merged, which would be nice to limit the number of total concepts. Also they have quite different responsibilities, so it might be fine to keep them separate. Any thoughts @cfallin?

Interestingly, this PR started as removingRegInfo from the TargetIsa trait since the adapter returned a dummy value there. From the fallout, noticed that all Display implementations didn't needed an ISA anymore (since these were only used to render ISA specific registers). Also the whole family of RegInfo / ValueLoc / RegUnit was exclusively used for the old backend, and these could be removed. Notably, some IR instructions needed to be removed, because they were using RegUnit too: this was the oddball of regfill / regmove / regspill / copy_special, which were IR instructions inserted by the old regalloc. Fare thee well!

Wasmtime GitHub notifications bot (Sep 30 2021 at 23:30):

bnjbvr edited PR #3402 from unify-targetisa-mach-backend to main:

This also paves the way for unifying TargetIsa and MachBackend, since now they map one to one. In theory the two traits could be merged, which would be nice to limit the number of total concepts. Also they have quite different responsibilities, so it might be fine to keep them separate. Any thoughts @cfallin?

Interestingly, this PR started as removingRegInfo from the TargetIsa trait since the adapter returned a dummy value there. From the fallout, noticed that all Display implementations didn't needed an ISA anymore (since these were only used to render ISA specific registers). Also the whole family of RegInfo / ValueLoc / RegUnit was exclusively used for the old backend, and these could be removed. Notably, some IR instructions needed to be removed, because they were using RegUnit too: this was the oddball of regfill / regmove / regspill / copy_special, which were IR instructions inserted by the old regalloc. Fare thee well!

(feel free to squash the commits before merging, the history of this PR is a bit messy right now)