[Tarantool-patches] [PATCH luajit] FFI: Fix recording of union initialization.
Maxim Kokryashkin
m.kokryashkin at tarantool.org
Mon Jul 17 14:31:33 MSK 2023
Hi!
Thanks for the review!
>
>>Hi, Max!
>>Thanks for the fixes!
>>
>>LGTM, with a minor reminder below.
>>I suppose, that Sergey concerned about test name in the `test:ok()`
>>routine.
>>
>>On 14.07.23, Maxim Kokryashkin wrote:
>>>
>>> Hi!
>>> Thanks for the review!
>>> Added a comment with the test description, the branch is force-pushed.
>>> Here is the diff for the test description:
>>> ==============================================
>>> diff --git a/test/tarantool-tests/lj-128-fix-union-init.test.lua b/test/tarantool-tests/lj-128-fix-union-init.test.lua
>>> index 6a49cec8..65ba0f28 100644
>>> --- a/test/tarantool-tests/lj-128-fix-union-init.test.lua
>>> +++ b/test/tarantool-tests/lj-128-fix-union-init.test.lua
>>> @@ -10,6 +10,46 @@ test:plan(NITERATIONS)
>>> local ffi = require('ffi')
>>> local union_type = ffi.typeof('union { uint32_t u; float f; }')
>>>
>>> +-- Before the patch, the `union_type` call resulted in the
>>> +-- initialization of both the integer and the float members
>>> +-- of the union, leading to undefined behavior since the
>>> +-- integer member was overwritten.
>>> +-- The IR was the following:
>>> +--
>>> +-- 0031 ------ LOOP ------------
>>> +-- 0032 u8 XLOAD [0x100684521] V
>>> +-- 0033 int BAND 0032 +12
>>> +-- 0034 > int EQ 0033 +0
>>> +-- 0035 > cdt CNEW +96
>>> +-- 0036 p64 ADD 0035 +16
>>> +-- 0037 u32 XSTORE 0036 0029 <--- `u` member init
>>> +-- 0038 flt XSTORE 0036 0022 <--- `f` member init
>>> +-- 0039 u32 XLOAD 0036
>>> +-- 0040 num CONV 0039 num.u32
>>> +-- 0041 num CONV 0029 num.int
>>> +-- 0042 > num EQ 0041 0040
>>> +-- 0043 + int ADD 0029 +1
>>> +-- 0044 > int LE 0043 0001
>>> +-- 0045 int PHI 0029 0043
>>> +--
>>> +-- After the patch, the initialization is performed only
>>> +-- for the first member of the union, so now IR looks
>>> +-- like this:
>>> +-- 0029 ------ LOOP ------------
>>> +-- 0030 u8 XLOAD [0x1047c4521] V
>>> +-- 0031 int BAND 0030 +12
>>> +-- 0032 > int EQ 0031 +0
>>> +-- 0033 } cdt CNEW +96
>>> +-- 0034 p64 ADD 0033 +16
>>> +-- 0035 } u32 XSTORE 0034 0027 <--- `u` member init
>>> +-- 0036 u32 CONV 0027 u32.int
>>> +-- 0037 num CONV 0036 num.u32
>>> +-- 0038 num CONV 0027 num.int
>>> +-- 0039 > num EQ 0038 0037
>>> +-- 0040 + int ADD 0027 +1
>>> +-- 0041 > int LE 0040 0001
>>> +-- 0042 int PHI 0027 0040
>>> +
>>> jit.opt.start('hotloop=1')
>>> for i = 1, NITERATIONS do
>>> test:ok(union_type(i).u == i)
>>
>>Minor: the description of the test is still missing.
>Fixed! Here is the diff:
>==============================================
>diff --git a/test/tarantool-tests/lj-128-fix-union-init.test.lua b/test/tarantool-tests/lj-128-fix-union-init.test.lua
>index 65ba0f28..93cbf3af 100644
>--- a/test/tarantool-tests/lj-128-fix-union-init.test.lua
>+++ b/test/tarantool-tests/lj-128-fix-union-init.test.lua
>@@ -52,7 +52,7 @@ local union_type = ffi.typeof('union { uint32_t u; float f; }')
>
> jit.opt.start('hotloop=1')
> for i = 1, NITERATIONS do
>- test:ok(union_type(i).u == i)
>+ test:ok(union_type(i).u == i, 'first member init only')
> end
>
> os.exit(test:check() and 0 or 1)
>==============================================
>
>The branch is force-pushed.
>>> ==============================================
>>
>><snipped>
>>
>>> >>> +for i = 1, NITERATIONS do
>>> >>> + test:ok(union_type(i).u == i)
>>> >>testcases description is missed, please add one.
>>> >>> +end
>>> >>> +
>>> >>> +os.exit(test:check() and 0 or 1)
>>> >
>>
>>--
>>Best regards,
>>Sergey Kaplun
>--
>Best regards,
>Maxim Kokryashkin
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