[Tarantool-patches] [PATCH luajit] Fix maxslots when recording BC_VARG, part 3.
Maxim Kokryashkin
m.kokryashkin at tarantool.org
Thu Aug 17 16:16:36 MSK 2023
Hi, Sergey!
Thanks for the fixes!
LGTM
On Wed, Aug 16, 2023 at 07:11:57PM +0300, Sergey Kaplun wrote:
> Hi, Maxim!
> Thanks for the review!
> Fixed your comments and force-pushed the branch.
>
> On 16.08.23, Maxim Kokryashkin wrote:
> > Hi, Sergey!
> > Thanks for the patch!
> > Please consider my comments below.
> >
> > On Tue, Aug 15, 2023 at 03:32:15PM +0300, Sergey Kaplun wrote:
> > > From: Mike Pall <mike>
> > >
> > > Thanks to Peter Cawley.
> > >
> > > (cherry-picked from commit abb27c7771947e082c9d919d184ad5f5f03e2e32)
> > >
> > > In case, when `BC_VARG` set the VARG slot to the non-top stack slot,
> > Typo: s/set/sets/
>
> Fixed.
>
> > > `maxslot` value was unconditionally set to the destination slot, so some
> > > top slots may be omitted in the snapshot entry. Since these slots are
> > > omitted, they are not restored correctly, when restoring from snapshot
> > Typo: s/snapshot/a snapshot/
>
> Fixed.
>
> > > for this side exit.
> > >
> > > This patch adds the check for the aforementioned case, to avoid maxslot
> > > shrinking.
> > >
> > > Sergey Kaplun:
> > > * added the description and the test for the problem
> > >
> > > Part of tarantool/tarantool#8825
> > > ---
> > >
> > > Branch: https://github.com/tarantool/luajit/tree/skaplun/lj-1046-fix-bc-varg-recording
> > > PR: https://github.com/tarantool/tarantool/pull/8986
> > > Related issues:
> > > * https://github.com/LuaJIT/LuaJIT/issues/1046
> > > * https://github.com/tarantool/tarantool/issues/8825
> > >
> > > src/lj_record.c | 12 +++-
> > > .../lj-1046-fix-bc-varg-recording.test.lua | 58 +++++++++++++++++++
> > > 2 files changed, 67 insertions(+), 3 deletions(-)
> > > create mode 100644 test/tarantool-tests/lj-1046-fix-bc-varg-recording.test.lua
> > >
> > > diff --git a/src/lj_record.c b/src/lj_record.c
> > > index 34d1210a..6bcdb04c 100644
> > > --- a/src/lj_record.c
> > > +++ b/src/lj_record.c
>
> <snipped>
>
> > > diff --git a/test/tarantool-tests/lj-1046-fix-bc-varg-recording.test.lua b/test/tarantool-tests/lj-1046-fix-bc-varg-recording.test.lua
> > > new file mode 100644
> > > index 00000000..34c5c572
> > > --- /dev/null
> > > +++ b/test/tarantool-tests/lj-1046-fix-bc-varg-recording.test.lua
> > > @@ -0,0 +1,58 @@
> > > +local tap = require('tap')
> > > +local test = tap.test('lj-1046-fix-bc-varg-recording'):skipcond({
> > > + ['Test requires JIT enabled'] = not jit.status(),
> > > +})
> > > +
> > > +test:plan(2)
> > > +
> > > +jit.opt.start('hotloop=1')
> > > +
> > > +-- luacheck: ignore
> > > +local anchor
> > > +local N_ITER = 5
> > > +local SIDE_ITER = N_ITER - 1
> > > +for i = 1, N_ITER do
> > > + -- In case, when `BC_VARG` set the VARG slot to the non-top
> > > + -- stack slot, `maxslot` value was unconditionally set to the
> > > + -- destination slot, so the following snapshot is used:
> > > + -- SNAP #4 [ ---- ---- ---- nil ]
> > > + -- instead of:
> > > + -- SNAP #4 [ ---- nil ---- ---- 0009 0001 ---- 0009 ]
> > Snapshot examples here ceratinly give the idea of what goes wrong,
> > but the `0009` and `0001` are meaningless by themselves. I think it would be
> > nice to include IRs here too.
>
> Added.
>
> > > + -- Since these slots are omitted, they are not restored
> > > + -- correctly, when restoring from snapshot for this side exit.
> > Please fix the same typos as in the commit message here.
>
> Fixed.
>
> > > + anchor = ...
> > > + if i > SIDE_ITER then
> > > + -- XXX: Don't use `test:ok()` here to avoid double-running of
> > I think better phrasing would be:
> > | `test:ok()` is not used here ...
>
> Fixed.
>
> > > + -- tests in case of `i` incorrect restoring from the snapshot.
> > Typo: s/restoring/restoration/
>
> Fixed.
>
> > > + assert(i > SIDE_ITER)
> > > + end
> > > +end
> > > +
> > > +test:ok(true, 'BC_VARG recording 0th frame depth, 1 result')
> > > +
> > > +-- Now the same case, but with an additional frame, so VARG slots
> > > +-- are defined on the trace.
> > > +local function varg_frame(anchor, i, side_iter, ...)
> > > + anchor = ...
> > > + -- In case, when `BC_VARG` set the VARG slot to the non-top
> > > + -- stack slot, `maxslot` value was unconditionally set to the
> > > + -- destination slot, so the following snapshot is used:
> > > + -- SNAP #4 [ <snipped> | nil nil nil `varg_frame` | nil ]
> > > + -- instead of:
> > > + -- SNAP #4 [ <snipped> | nil nil nil `varg_frame` | nil 0009 0005 ]
> > > + -- Since these slots are omitted, they are not restored
> > > + -- correctly, when restoring from snapshot for this side exit.
> > I guess we don't need to repeat the entire comment again.
>
> Dropped then.
>
> > > + if i > side_iter then
> > > + -- XXX: Don't use `test:ok()` here to avoid double-running of
> > > + -- tests in case of `i` incorrect restoring from the snapshot.
> > Same typos as in the comment above.
>
> Fixed.
>
> > > + assert(i > side_iter)
>
> See the iterative patch below. Branch is force-pushed.
>
> ===================================================================
> diff --git a/test/tarantool-tests/lj-1046-fix-bc-varg-recording.test.lua b/test/tarantool-tests/lj-1046-fix-bc-varg-recording.test.lua
> index 34c5c572..30a87e54 100644
> --- a/test/tarantool-tests/lj-1046-fix-bc-varg-recording.test.lua
> +++ b/test/tarantool-tests/lj-1046-fix-bc-varg-recording.test.lua
> @@ -12,18 +12,39 @@ local anchor
> local N_ITER = 5
> local SIDE_ITER = N_ITER - 1
> for i = 1, N_ITER do
> - -- In case, when `BC_VARG` set the VARG slot to the non-top
> + -- This trace generates the following IRs:
> + -- 0001 > int SLOAD #7 CRI
> + -- 0002 > int LE 0001 +2147483646
> + -- 0003 int SLOAD #6 CI
> + -- 0004 int SLOAD #0 FR
> + -- 0005 > int LE 0004 +11
> + -- 0006 > num SLOAD #5 T
> + -- 0007 num CONV 0003 num.int
> + -- .... SNAP #1 [ ---- ---- ---- nil ]
> + -- 0008 > num ULE 0007 0006
> + -- 0009 + int ADD 0003 +1
> + -- .... SNAP #2 [ ---- ---- ---- nil ---- ---- ]
> + -- 0010 > int LE 0009 0001
> + -- .... SNAP #3 [ ---- ---- ---- nil ---- ---- 0009 0001 ---- 0009 ]
> + -- 0011 ------ LOOP ------------
> + -- 0012 num CONV 0009 num.int
> + -- .... SNAP #4 [ ---- ---- ---- nil ]
> + --
> + -- In case, when `BC_VARG` sets the VARG slot to the non-top
> -- stack slot, `maxslot` value was unconditionally set to the
> - -- destination slot, so the following snapshot is used:
> - -- SNAP #4 [ ---- ---- ---- nil ]
> + -- destination slot, so the following snapshot (same for the #1)
> + -- is used:
> + -- .... SNAP #4 [ ---- ---- ---- nil ]
> -- instead of:
> - -- SNAP #4 [ ---- nil ---- ---- 0009 0001 ---- 0009 ]
> + -- .... SNAP #4 [ ---- ---- ---- nil ---- ---- 0009 0001 ---- 0009 ]
> -- Since these slots are omitted, they are not restored
> - -- correctly, when restoring from snapshot for this side exit.
> + -- correctly, when restoring from the snapshot for this side
> + -- exit.
> anchor = ...
> if i > SIDE_ITER then
> - -- XXX: Don't use `test:ok()` here to avoid double-running of
> - -- tests in case of `i` incorrect restoring from the snapshot.
> + -- XXX: `test:ok()` isn't used here to avoid double-running of
> + -- tests in case of `i` incorrect restoration from the
> + -- snapshot.
> assert(i > SIDE_ITER)
> end
> end
> @@ -34,17 +55,10 @@ test:ok(true, 'BC_VARG recording 0th frame depth, 1 result')
> -- are defined on the trace.
> local function varg_frame(anchor, i, side_iter, ...)
> anchor = ...
> - -- In case, when `BC_VARG` set the VARG slot to the non-top
> - -- stack slot, `maxslot` value was unconditionally set to the
> - -- destination slot, so the following snapshot is used:
> - -- SNAP #4 [ <snipped> | nil nil nil `varg_frame` | nil ]
> - -- instead of:
> - -- SNAP #4 [ <snipped> | nil nil nil `varg_frame` | nil 0009 0005 ]
> - -- Since these slots are omitted, they are not restored
> - -- correctly, when restoring from snapshot for this side exit.
> if i > side_iter then
> - -- XXX: Don't use `test:ok()` here to avoid double-running of
> - -- tests in case of `i` incorrect restoring from the snapshot.
> + -- XXX: `test:ok()` isn't used here to avoid double-running of
> + -- tests in case of `i` incorrect restoration from the
> + -- snapshot.
> assert(i > side_iter)
> end
> end
> ===================================================================
>
> <snipped>
>
> > >
>
> --
> Best regards,
> Sergey Kaplun
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