[Tarantool-patches] [PATCH luajit] Fix FOLD rule for BUFHDR append.

[Igor Munkin]

Sergey,

I've checked the patchset into all long-term branches in
tarantool/luajit and bumped a new version in master, release/2.11 and
release/2.10.

On 14.11.23, Sergey Kaplun via Tarantool-patches wrote:
> From: Mike Pall <mike>
> 
> Reported by XmiliaH.
> 
> (cherry-picked from commit bc1bdbf620f58f0978385828bc51272903601e17)
> 
> `bufput_append()` may fold `BUFHDR RESET` + `BUFPUT` IRs to `BUFHDR
> APPEND` even if the right operand (`BUFSTR`) is the PHI. If it's not the
> last IR in the `BUFSTR` chain, this may lead to an incorrect resulting
> value in the buffer, which contains a longer string since `APPEND` is
> used instead of `RESET`.
> 
> This patch adds the corresponding check inside the fold rule.
> 
> Sergey Kaplun:
> * added the description and the test for the problem
> 
> Part of tarantool/tarantool#9145
> ---
> 
> Branch: https://github.com/tarantool/luajit/tree/skaplun/lj-791-fold-bufhdr-append
> Tarantool PR: https://github.com/tarantool/tarantool/pull/9369
> Relate issues:
> * https://github.com/LuaJIT/LuaJIT/issues/791
> * https://github.com/tarantool/tarantool/issues/9145
> 
>  src/lj_opt_fold.c                             |  3 +-
>  .../lj-791-fold-bufhdr-append.test.lua        | 54 +++++++++++++++++++
>  2 files changed, 56 insertions(+), 1 deletion(-)
>  create mode 100644 test/tarantool-tests/lj-791-fold-bufhdr-append.test.lua
> 

<snipped>

> -- 
> 2.42.0
> 

-- 
Best regards,
IM