Stream: git-wasmtime

Topic: wasmtime / PR #5092 s390x: use constraints for call argum...

Wasmtime GitHub notifications bot (Oct 21 2022 at 17:19):

uweigand opened PR #5092 from s390x-call-abi to main:

Use the regalloc constraint-based CallArgList / CallRetList mechanism instead of directly using physregs in instructions.

CC @cfallin @elliottt

Note that this patch continues to emit calls directly from ISLE. I tried to use the common gen_call, but that would require several extensions to properly support s390x:

• We need to use accumulate_outgoing_args_size instead of emit_stack_pre_adjust / emit_stack_post_adjust.
• ImplicitPtrArg and the register version of StructArg are only implemented in ISLE right now.
• We need to lane-swap vector registers in case of a caller/callee ABI mismatch.

Except for that last point, I have some implementation prototypes. But even so, the resulting code was of lower quality than what I get with the ISLE-based logic today - in particular, with the ISLE logic we can better fold incoming argument expressions (e.g. into sign extension, or into the address used for a memory copy instruction). Therefore I decided to stay with this approach.

The generated code remains the same except for register allocation and instruction scheduling differences.

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Wasmtime GitHub notifications bot (Oct 21 2022 at 18:01):

cfallin submitted PR review.

Wasmtime GitHub notifications bot (Oct 21 2022 at 18:01):

cfallin merged PR #5092.

Last updated: Oct 23 2024 at 20:03 UTC