Re: [Tarantool-patches] [PATCH luajit] x64/LJ_GC64: Fix type-check-only variant of SLOAD.

[sergos via Tarantool-patches <tarantool-patches@dev.tarantool.org>]

Hi!

Thanks for the patch!

LGTM with fixes after Max’s review. 

Although, as we discussed earlier I would prefer the test has
`skipcond(not ffi.abi('gc64’), 'test is GC64 only')`

regards,
Sergos

> On 6 Dec 2022, at 11:49, Sergey Kaplun <skaplun@tarantool.org> wrote:
> 
> Hi, Maxim!
> 
> Thanks for the review!
> 
> Fixed you comments.
> 
> On 06.12.22, Maxim Kokryashkin wrote:
>> 
>> Hi, Sergey!
>> Thanks for the patch!
>> Please consider my comments below.
>>>  
> 
> <snipped>
> 
>>>> ---
>>>> 
>>>> Branch:  https://github.com/tarantool/luajit/tree/skaplun/lj-350-fix-sload-typecheck-full-ci
>>>> Issues:
>>>> *  https://github.com/tarantool/tarantool/issues/7230
>>>> *  https://github.com/LuaJIT/LuaJIT/pull/350
>>>> Tarantool PR:  https://github.com/tarantool/tarantool/pull/7995
>>>> 
>>>>  src/lj_asm_x86.h | 2 +-
>>>>  .../lj-350-sload-typecheck.test.lua | 42 +++++++++++++++++++
>>>>  .../lj-408-tonumber-cdata-record.test.lua | 10 -----
>>>>  3 files changed, 43 insertions(+), 11 deletions(-)
>>>>  create mode 100644 test/tarantool-tests/lj-350-sload-typecheck.test.lua
>>>> 
>>>> diff --git a/src/lj_asm_x86.h b/src/lj_asm_x86.h
>>>> index 8a4d4025..8efda8e5 100644
>>>> --- a/src/lj_asm_x86.h
>>>> +++ b/src/lj_asm_x86.h
> 
> <snipped>
> 
>>>> diff --git a/test/tarantool-tests/lj-350-sload-typecheck.test.lua b/test/tarantool-tests/lj-350-sload-typecheck.test.lua
>>>> new file mode 100644
>>>> index 00000000..6ffc61fb
>>>> --- /dev/null
>>>> +++ b/test/tarantool-tests/lj-350-sload-typecheck.test.lua
>>>> @@ -0,0 +1,42 @@
>>>> +local tap = require('tap')
>>>> +local traceinfo = require('jit.util').traceinfo
>>>> +
>>>> +-- Test file to demonstrate the incorrect GC64 JIT asembling
>>>> +-- `IR_SLOAD`.
>>>> +-- See also  https://github.com/LuaJIT/LuaJIT/pull/350 .
>>>> +local test = tap.test('lj-350-sload-typecheck')
>>>> +
>>>> +test:plan(1)
>>>> +
>>>> +-- Contains only IR_SLOAD after recording.
>>>> +local function sload(arg)
>>>> + return arg
>>>> +end
>>>> +
>>>> +local tab_arg = {}
>>>> +
>>>> +-- Reset JIT, remove any other traces.
>>>> +jit.off()
>>>> +jit.flush()
>>>> +
>>>> +assert(not traceinfo(1), 'no traces compiled after flush')
>>>> +
>>>> +-- Try to executed compiled trace wiht IR_SLOAD, if emitted mcode
>>> Typo: s/to executed/to execute
>>> Typo: s/wiht/with
>>> Typo: s/if emitted/if the emmited
> 
> Fixed.
> 
>>>> +-- is incorrect, assertion guard type check will failed even for
>>> Typo: s/failed/fail
>>> Typo: s/for/ for the
> 
> Fixed.
> 
> See the iterative patch below:
> 
> ===================================================================
> diff --git a/test/tarantool-tests/lj-350-sload-typecheck.test.lua b/test/tarantool-tests/lj-350-sload-typecheck.test.lua
> index 6ffc61fb..33794943 100644
> --- a/test/tarantool-tests/lj-350-sload-typecheck.test.lua
> +++ b/test/tarantool-tests/lj-350-sload-typecheck.test.lua
> @@ -21,9 +21,9 @@ jit.flush()
> 
> assert(not traceinfo(1), 'no traces compiled after flush')
> 
> --- Try to executed compiled trace wiht IR_SLOAD, if emitted mcode
> --- is incorrect, assertion guard type check will failed even for
> --- correct type of argument and a new trace is recorded.
> +-- Try to execute the compiled trace with IR_SLOAD, if the emitted
> +-- mcode is incorrect, assertion guard type check will fail even
> +-- for the correct type of argument and a new trace is recorded.
> jit.opt.start('hotloop=1', 'hotexit=1')
> 
> jit.on()
> ===================================================================
> 
> Branch is force-pushed.
> 
>>>> +-- correct type of argument and a new trace is recorded.
>>>> +jit.opt.start('hotloop=1', 'hotexit=1')
>>>> +
>>>> +jit.on()
>>>> +
>>>> +-- Make the function hot.
>>>> +sload(tab_arg)
>>>> +-- Compile the trace.
>>>> +sload(tab_arg)
>>>> +-- Execute trace and try to compile a trace from the side exit.
>>>> +sload(tab_arg)
>>>> +
>>>> +jit.off()
>>>> +
>>>> +test:ok(not traceinfo(2), 'the second trace should not be compiled')
>>>> +
>>>> +os.exit(test:check() and 0 or 1)
>>> Also, that test passes even without the patch on Linux x86_64 GC64: OFF
> 
> Yes, because patch fixes the behaviour only for GC64 as mentioned in the
> commit message.
> 
>>>> diff --git a/test/tarantool-tests/lj-408-tonumber-cdata-record.test.lua b/test/tarantool-tests/lj-408-tonumber-cdata-record.test.lua
>>>> index bf9e8e46..a8235e93 100644
>>>> --- a/test/tarantool-tests/lj-408-tonumber-cdata-record.test.lua
>>>> +++ b/test/tarantool-tests/lj-408-tonumber-cdata-record.test.lua
> 
> <snipped>
> 
>>>> 2.34.1
>>> --
>>> Best regards,
>>> Maxim Kokryashkin
> 
> -- 
> Best regards,
> Sergey Kaplun