Hi, Max!
thanks for the patch!
See my comments inline.
Sergey
On 7/10/23 18:56, Maksim Kokryashkin wrote:
> From: Mike Pall <mike>
>
> Thanks to Alex Shpilkin.
>
> (cherry-picked from commit 56c04accf975bff2519c34721dccbbdb7b8e6963)
>
> As stated here[1], only the first field of a union can be
> initialized with a flat initializer. However, before this
> patch, on-trace initialization instructions were emitted
> for other union members too, overwriting the previous
> initialization values.
>
> This patch fixes the mentioned behavior by preventing
> initialization of members other than the first one.
>
> [1]:
https://luajit.org/ext_ffi_semantics.html#init>
> Maxim Kokryashkin:
> * added the description and the test for the problem
>
> Part of tarantool/tarantool#8825
> ---
> Branch:
https://github.com/tarantool/luajit/tree/fckxorg/lj-128-fix-union-init> PR:
https://github.com/tarantool/tarantool/pull/8867> Original LuaJIT PR:
https://github.com/LuaJIT/LuaJIT/pull/650>
> src/lj_crecord.c | 5 +++++
> .../lj-128-fix-union-init.test.lua | 18 ++++++++++++++++++
> 2 files changed, 23 insertions(+)
> create mode 100644 test/tarantool-tests/lj-128-fix-union-init.test.lua
>
> diff --git a/src/lj_crecord.c b/src/lj_crecord.c
> index 0008a865..ffe995f4 100644
> --- a/src/lj_crecord.c
> +++ b/src/lj_crecord.c
> @@ -1065,6 +1065,11 @@ static void crec_alloc(jit_State *J, RecordFFData *rd, CTypeID id)
> dp = emitir(IRT(IR_ADD, IRT_PTR), trcd,
> lj_ir_kintp(J, df->size + sizeof(GCcdata)));
> crec_ct_tv(J, dc, dp, sp, sval);
> + if ((d->info & CTF_UNION)) {
> + if (d->size != dc->size) /* NYI: partial init of union. */
> + lj_trace_err(J, LJ_TRERR_NYICONV);
> + break;
> + }
> } else if (!ctype_isconstval(df->info)) {
> /* NYI: init bitfields and sub-structures. */
> lj_trace_err(J, LJ_TRERR_NYICONV);
> diff --git a/test/tarantool-tests/lj-128-fix-union-init.test.lua b/test/tarantool-tests/lj-128-fix-union-init.test.lua
> new file mode 100644
> index 00000000..6a49cec8
> --- /dev/null
> +++ b/test/tarantool-tests/lj-128-fix-union-init.test.lua
> @@ -0,0 +1,18 @@
> +local tap = require('tap')
> +local test = tap.test('lj-128-fix-union-init'):skipcond({
> + ['Test requires JIT enabled'] = not jit.status(),
> +})
> +
> +local NITERATIONS = 4
> +
> +test:plan(NITERATIONS)
> +
> +local ffi = require('ffi')
> +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)
testcases description is missed, please add one.
> +end
> +
> +os.exit(test:check() and 0 or 1)