Stream: git-wasmtime

Topic: wasmtime / PR #14629 cranelift(x64): reject callee-pop st...

Wasmtime GitHub notifications bot (Oct 09 2026 at 17:10):

rvolosatovs opened PR #14629 from rvolosatovs:fix/x64-large-callee-pop to bytecodealliance:main:

The tail and winch calling conventions pop their stack arguments on return, which x64 does with ret imm16. gen_return converted the size with u16::try_from(..).unwrap(), but stack arguments may be up to 128 MiB, so compiling a tail or winch function with 64 KiB or more of stack arguments, or a tail function that return_calls such a callee, panicked.

Reject such signatures with CodegenError::ImplLimitExceeded in compute_arg_locs, alongside the existing stack-argument size limit. Since this runs for every signature a function references, it also covers the callee's signature at return_call sites, which grows the caller's tail-argument area. Other backends pop with an sp adjustment and aren't affected. Wasm can't reach this: 1000 parameters is about 16 KiB of stack arguments.

Wasmtime GitHub notifications bot (Oct 09 2026 at 18:52):

github-actions[bot] added the label cranelift on PR #14629.

Wasmtime GitHub notifications bot (Oct 09 2026 at 18:52):

github-actions[bot] added the label cranelift:area:x64 on PR #14629.

Wasmtime GitHub notifications bot (Oct 09 2026 at 22:58):

:thumbs_up: cfallin submitted PR review:

This is still in Draft but it looks right to me if you're happy to mark as ready and merge it!

Wasmtime GitHub notifications bot (Oct 10 2026 at 06:13):

rvolosatovs has marked PR #14629 as ready for review.

Wasmtime GitHub notifications bot (Oct 10 2026 at 06:13):

rvolosatovs requested fitzgen for a review on PR #14629.

Wasmtime GitHub notifications bot (Oct 10 2026 at 06:13):

rvolosatovs requested wasmtime-compiler-reviewers for a review on PR #14629.

Wasmtime GitHub notifications bot (Oct 10 2026 at 06:13):

rvolosatovs added PR #14629 cranelift(x64): reject callee-pop stack args that don't fit ret imm16 to the merge queue

Wasmtime GitHub notifications bot (Oct 10 2026 at 06:36):

github-merge-queue[bot] removed PR #14629 cranelift(x64): reject callee-pop stack args that don't fit ret imm16 from the merge queue

Wasmtime GitHub notifications bot (Oct 10 2026 at 06:49):

rvolosatovs updated PR #14629.

Wasmtime GitHub notifications bot (Oct 10 2026 at 06:49):

rvolosatovs has enabled auto merge for PR #14629.

Wasmtime GitHub notifications bot (Oct 10 2026 at 07:00):

rvolosatovs added PR #14629 cranelift(x64): reject callee-pop stack args that don't fit ret imm16 to the merge queue

Wasmtime GitHub notifications bot (Oct 10 2026 at 07:25):

:check: rvolosatovs merged PR #14629.

Wasmtime GitHub notifications bot (Oct 10 2026 at 07:25):

rvolosatovs removed PR #14629 cranelift(x64): reject callee-pop stack args that don't fit ret imm16 from the merge queue

Last updated: Oct 11 2026 at 04:10 UTC