From: Sergey Kaplun via Tarantool-patches <tarantool-patches@dev.tarantool.org> To: Sergey Ostanevich <sergos@tarantool.org>, Igor Munkin <imun@tarantool.org> Cc: tarantool-patches@dev.tarantool.org Subject: [Tarantool-patches] [PATCH luajit] LJ_GC64: Fix IR_VARG offset for fixed number of results. Date: Wed, 13 Jul 2022 12:53:49 +0300 [thread overview] Message-ID: <20220713095349.31718-1-skaplun@tarantool.org> (raw) From: Mike Pall <mike> Reported by George Vaintrub. Fixed by Sergey Kaplun. (cherry picked from commit 6bda30d8c745b3963ba870221b9be6acdffed9b1) This bug occurs when recording `BC_VARG` with the following conditions: 1) varargs undefined on trace. 2) known fixed number of results. For this case the vararg slots loads via `IR_VLOAD` by offset from vararg base. In GC64 mode this offset was miscounting due to missing `LJ_FR2` correction in the base TRef calculation. As the result the wrong (+1) vararg slot is used. This patch adds the missing the aforementioned `LJ_FR2` correction. Sergey Kaplun: * added the description and the test for the problem Resolves tarantool/tarantool#7172 Part of tarantool/tarantool#7230 --- Branch: https://github.com/tarantool/luajit/tree/skaplun/lj-864-varg-rec-base-offset-full-ci Issues: * https://github.com/tarantool/tarantool/issues/7172 * https://github.com/LuaJIT/LuaJIT/issues/864 src/lj_record.c | 2 +- .../lj-864-varg-rec-base-offset.test.lua | 25 +++++++++++++++++++ 2 files changed, 26 insertions(+), 1 deletion(-) create mode 100644 test/tarantool-tests/lj-864-varg-rec-base-offset.test.lua diff --git a/src/lj_record.c b/src/lj_record.c index a11f3712..9e2e1d9e 100644 --- a/src/lj_record.c +++ b/src/lj_record.c @@ -1794,7 +1794,7 @@ static void rec_varg(jit_State *J, BCReg dst, ptrdiff_t nresults) emitir(IRTGI(IR_EQ), fr, lj_ir_kint(J, (int32_t)frame_ftsz(J->L->base-1))); vbase = emitir(IRT(IR_SUB, IRT_IGC), REF_BASE, fr); - vbase = emitir(IRT(IR_ADD, IRT_PGC), vbase, lj_ir_kint(J, frofs-8)); + vbase = emitir(IRT(IR_ADD, IRT_PGC), vbase, lj_ir_kint(J, frofs-8*(1+LJ_FR2))); for (i = 0; i < nload; i++) { IRType t = itype2irt(&J->L->base[i-1-LJ_FR2-nvararg]); TRef aref = emitir(IRT(IR_AREF, IRT_PGC), diff --git a/test/tarantool-tests/lj-864-varg-rec-base-offset.test.lua b/test/tarantool-tests/lj-864-varg-rec-base-offset.test.lua new file mode 100644 index 00000000..ca30f92f --- /dev/null +++ b/test/tarantool-tests/lj-864-varg-rec-base-offset.test.lua @@ -0,0 +1,25 @@ +local tap = require('tap') + +-- Test file to demonstrate LuaJIT misbehaviour during recording +-- BC_VARG with nvarargs >= nresults in GC64 mode. +-- See also https://github.com/LuaJIT/LuaJIT/issues/864, +-- https://github.com/tarantool/tarantool/issues/7172. +local test = tap.test('lj-864-varg-rec-base-offset') +test:plan(1) + +jit.opt.start('hotloop=1') + +local MAGIC = 42 +local function test_rec_varg(...) + local slot1 + for _ = 1, 3 do + slot1 = ... + end + return slot1 == MAGIC +end + +-- Test case for nvarargs >= nresults. Equality is not suitable +-- due to failing assertion guard for type of loaded vararg slot. +test:ok(test_rec_varg(MAGIC, 0), 'correct BC_VARG recording') + +os.exit(test:check() and 0 or 1) -- 2.34.1
next reply other threads:[~2022-07-13 9:56 UTC|newest] Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top 2022-07-13 9:53 Sergey Kaplun via Tarantool-patches [this message] 2022-07-14 11:54 ` sergos via Tarantool-patches 2022-07-15 14:44 ` Sergey Kaplun via Tarantool-patches 2022-07-15 15:03 ` sergos via Tarantool-patches 2022-07-19 0:14 ` Igor Munkin via Tarantool-patches 2022-08-10 14:32 ` Igor Munkin via Tarantool-patches
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