Stream: git-wasmtime

Topic: wasmtime / PR #5116 s390x: Fix handling of sret arguments

Wasmtime GitHub notifications bot (Oct 25 2022 at 09:43):

uweigand opened PR #5116 from s390x-sret to main:

Skip synthetic StructReturn entries in the return value list. Fixes https://github.com/bytecodealliance/wasmtime/issues/5089

CC @cfallin

This mirrors the implementation in gen_call_common, and does fix the actual crash. I still think this could be improved further:

• It's unfortunate that whether or not a synthetic StructReturn was added cannot be discovered solely from looking at the Sig (or SigData) - at the moment you always have to look at the SigRef as well.
• There appears to be a discrepancy between call_clobbers, which considers all StructReturn return values as clobbers, and gen_call_common, which only skips those StructReturns that were added by missing_struct_return. Shouldn't these two be in sync? (OTOH does any code ever actually have a StructReturn on the return list that isn't added by missing_struct_return?)
• This whole mechanism probably should be platform-specific anyway. The fact that the incoming return-buffer address needs to be preserved in a return register is a property of the Intel ABI only - AFAIK none of the other ABIs we support have that requirement (s390x certainly does not).

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Wasmtime GitHub notifications bot (Oct 25 2022 at 17:40):

cfallin submitted PR review.

Wasmtime GitHub notifications bot (Oct 25 2022 at 17:40):

cfallin merged PR #5116.

Last updated: Oct 23 2024 at 20:03 UTC