Re: [Tarantool-patches] [PATCH luajit v1 1/5] build: introduce option LUAJIT_ENABLE_TABLE_BUMP

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

Hi, Sergey!
Thanks for the review!

On 06.06.24, Sergey Bronnikov wrote:
> Hi, Sergey
> 
> 
> thanks for the patch! Please see a question below.
> 
> On 22.04.2024 11:49, Sergey Kaplun wrote:
> > This option enables table bump optimization if sink optimization is
> > enabled. The table bump optimization patches the bytecodes with a table
> > allocation on the trace recording if the recorded trace exceeds the size
> > of the allocated table. This optimization still has some bugs, so it is
> > disabled by default. For more details, see the comment in
> > <CMakeLists.txt>.
> >
> > Needed for tarantool/tarantool#9924
> > ---
> >   CMakeLists.txt | 17 +++++++++++++++++
> >   1 file changed, 17 insertions(+)
> >
> > diff --git a/CMakeLists.txt b/CMakeLists.txt
> > index 2355ce17..52014296 100644
> > --- a/CMakeLists.txt
> > +++ b/CMakeLists.txt
> > @@ -307,6 +307,23 @@ if(LUAJIT_ENABLE_COVERAGE)
> >     include(CodeCoverage)
> >   endif()
> >   
> > +# Enable table bump optimization. This optimization patches the
> > +# bytecodes with a table allocation on the trace recording if the
> > +# recorded trace exceeds the size of the allocated table.
> > +# This optimization still has some bugs, so it is disabled by
> > +# default. See also:https://github.com/LuaJIT/LuaJIT/issues/606.
> > +option(LUAJIT_ENABLE_TABLE_BUMP "Enable table bump optimization" OFF)
> > +if(LUAJIT_ENABLE_TABLE_BUMP)
> > +  # Within table bump optimization enabled (and due to our
> > +  # modification related to metrics), some offsets in `GG_State`
> > +  # stop fit in 12bit immediate. Hence, the build failed due to
> > +  # the DASM error (DASM_S_RANGE_I).
> > +  if(CMAKE_SYSTEM_PROCESSOR STREQUAL "aarch64")
> > +    message(FATAL_ERROR "Table Bump optimization is unsupported for aarch64")
> 
> Table optimization works on all architectures supported by LuaJIT except 
> aarch64, right?

In the upstream, it works on all architectures. We have a problem
building LuaJIT for aarch64 due to our metrics that too grows the
`GG_State`.

> 
> 
> > +  endif()
> > +  AppendFlags(TARGET_C_FLAGS -DLUAJIT_ENABLE_TABLE_BUMP)
> > +endif()
> > +
> >   # --- Main source tree ---------------------------------------------------------
> >   
> >   add_subdirectory(src)

-- 
Best regards,
Sergey Kaplun