From: Igor Munkin via Tarantool-patches <tarantool-patches@dev.tarantool.org> To: Sergey Kaplun <skaplun@tarantool.org> Cc: tarantool-patches@dev.tarantool.org Subject: Re: [Tarantool-patches] [PATCH luajit] Fix bytecode register allocation for comparisons. Date: Tue, 17 Aug 2021 12:24:11 +0300 [thread overview] Message-ID: <20210817092410.GE5743@tarantool.org> (raw) In-Reply-To: <20210719073632.12008-1-skaplun@tarantool.org> Sergey, I've checked the patch into all long-term branches in tarantool/luajit and bumped a new version in 1.10, 2.7, 2.8 and master. On 19.07.21, Sergey Kaplun wrote: > From: Mike Pall <mike> > > (cherry picked from commit 2f3f07882fb4ad9c64967d7088461b1ca0a25d3a) > > When LuaJIT is build with LJ_FR2 (GC64), information about frame takes > two slots -- the first takes the TValue with the function to call, the > second takes the additional frame information. The recording JIT > machinery works pretty the same -- the function IR_KGC is loaded in the > first slot, and the second is set to TREF_FRAME value. This value > should be rewritten after return from a callee. It is done either by the > return values either this slot is cleared (set to zero) manually with > the next bytecode with RA dst mode with the assumption, that the dst RA > takes the next slot after TREF_FRAME, i.e. an earlier instruction uses > the smallest possible destination register (see `lj_record_ins()` for > the details). > > Bytecode allocator swaps operands for ISGT and ISGE comparisons. > When it happens, the aforementioned rule for registers allocations > may be violated. When it happens, and this chunk is recording, the slot > with TREF_FRAME is not rewritten (but the next empty slot after > TREF_FRAME is) during bytecode recording. This leads to JIT slots > inconsistency and assertion failure in `rec_check_slots()` during > recording the next bytecode instruction. > > This patch fixes bytecode register allocation by changing the register > allocation order in case of ISGT and ISGE bytecodes. > > Sergey Kaplun: > * added the description and the test for the problem > > Resolves tarantool/tarantool#6227 > --- > > Branch: https://github.com/tarantool/luajit/tree/skaplun/gh-6227-fix-bytecode-allocator-for-comp > Tarantool branch: https://github.com/tarantool/tarantool/tree/skaplun/gh-6227-fix-bytecode-allocator-for-comp > Issue: https://github.com/tarantool/tarantool/issues/6227 > > src/lj_parse.c | 7 +++- > ...ytecode-allocator-for-comparisons.test.lua | 41 +++++++++++++++++++ > 2 files changed, 46 insertions(+), 2 deletions(-) > create mode 100644 test/tarantool-tests/gh-6227-bytecode-allocator-for-comparisons.test.lua > <snipped> > -- > 2.31.0 > -- Best regards, IM
prev parent reply other threads:[~2021-08-17 9:49 UTC|newest] Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top 2021-07-19 7:36 Sergey Kaplun via Tarantool-patches 2021-08-01 10:43 ` Igor Munkin via Tarantool-patches 2021-08-01 17:10 ` Sergey Kaplun via Tarantool-patches 2021-08-16 7:20 ` Igor Munkin via Tarantool-patches 2021-08-16 16:40 ` Sergey Kaplun via Tarantool-patches 2021-08-16 16:27 ` Igor Munkin via Tarantool-patches 2021-08-17 7:36 ` Vitaliia Ioffe via Tarantool-patches 2021-08-10 17:03 ` Sergey Ostanevich via Tarantool-patches 2021-08-16 16:44 ` Sergey Kaplun via Tarantool-patches 2021-08-17 9:24 ` Igor Munkin via Tarantool-patches [this message]
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