MatchData#end returns invalid offset when called within evalAsync

[palkan]

Stackblitz reproduction: https://stackblitz.com/edit/ruby-wasm-demo-78s71k?file=index.html

MatchData#end returns incorrect match offset when used in async context:

vm.eval(/(т)(е)(с)/.match('тест').end(0)) #=> 3
vm.eval(/(т)(е)(с)/.match('тест').end(1)) #=> 1

vm.evalAsync(/(т)(е)(с)/.match('тест').end(0)) #=> 3291
vm.evalAsync(/(т)(е)(с)/.match('тест').end(1)) #=> 3

[palkan]

Good news: the head version works fine.

[kateinoigakukun]

I'll bisect which nightly head version fixed the issue once I'll get a stable internet connection.

[palkan]

This also crashes Date._parse (within evalAsync):

app.wasm:0x5739f8 Uncaught RuntimeError: memory access out of bounds
    at enc_strlen (app.wasm:0x5739f7)
    at rb_enc_strlen (app.wasm:0x573574)
    at update_char_offset (app.wasm:0x50cc96)
    at match_begin (app.wasm:0x507547)
    at ractor_safe_call_cfunc_1 (app.wasm:0x67a681)
    at vm_call0_body (app.wasm:0x638879)
    at rb_funcallv_scope (app.wasm:0x637cdb)
    at rb_funcall (app.wasm:0x65269f)
    at subx (app.wasm:0x7ed59)
    at date__parse (app.wasm:0x7bd9b)

[palkan]

Okay, I found the fix 😁—https://github.com/ruby/ruby/commit/0d4de0f4b1b9ac90be437bf1bac6851dd1d96fd0:

Author: Yuta Saito <[email protected]>
Date:   Mon Jan 29 09:49:15 2024 +0000

    wasm: align fiber stack pointer to 16 bytes

    In WebAssembly C ABI, the linear stack pointer must be always aligned
    to 16 bytes like other archs.
    The misaligned stack pointer causes some weird memory corruption since
    compiler assumes the aligned stack pointer.

[kateinoigakukun]

I'm sorry about totally forgetting my fix in January... I opened backport PRs for 3.2 and 3.3:

• https://github.com/ruby/ruby/pull/12100
• https://github.com/ruby/ruby/pull/12101