[Tarantool-patches] [PATCH] cmake: add LTO support for building luajit
Sergey Bronnikov
sergeyb at tarantool.org
Mon May 25 18:43:00 MSK 2020
I can confirm, formatting is fixed now.
LGTM
On 18:12 Mon 25 May , Olga Arkhangelskaia wrote:
> New diff is below:
>
> endif()
> - # XCode linker dynamically load libLTO.dylib to perform
> - # link-time optimization.
> - #
> http://lists.llvm.org/pipermail/llvm-dev/2009-November/027103.html
> + # XCode linker dynamically load libLTO.dylib to perform
> + # link-time optimization.
> + #
> http://lists.llvm.org/pipermail/llvm-dev/2009-November/027103.html
> if (NOT TARGET_OS_DARWIN)
> # llvm-ar is just a wrapper over ar to pass --plugin=
> option,
> # so that ar can understand LTO objects.
> @@ -248,7 +248,7 @@ macro(luajit_build)
> set (CMAKE_AR llvm-ar)
> endif()
> else()
> - # GNU opts to support lto
> + # GNU opts to support lto
> # Due to some problems (bugs, slow work, etc) we support LTO
> # only for 5.0+. The same is for binutils prior to 2.27
> # See comments in scripts/Makefile.lto in scope of
> @@ -256,7 +256,7 @@ macro(luajit_build)
> if (NOT ${CMAKE_CXX_COMPILER_VERSION} VERSION_LESS 5.0
> AND NOT ${linker_version} VERSION_LESS 2.27)
> set (luajit_cflags ${luajit_cflags} -flto
> -fuse-linker-plugin -fno-fat-lto-objects)
> - endif()
> + endif()
>
> 25.05.2020 15:58, Sergey Bronnikov пишет:
> > Olya,
> >
> > I have reviewed patch in a branch and below my comments.
> >
> > formatting issues still exist:
> >
> > + if (CMAKE_COMPILER_IS_CLANG)
> > + if (${CMAKE_CXX_COMPILER_VERSION} VERSION_LESS 3.9)
> > + set (luajit_cflags ${luajit_cflags} -flto=full)
> > + else()
> > + # ThinLTO that is both scalable and incremental
> > + # due to parallel IPO, available since 3.9 and above.
> > + # See http://blog.llvm.org/2016/06/thinlto-scalable-and-incremental-lto.html
> > + set (luajit_cflags ${luajit_cflags} -flto=thin)
> > + endif()
> > + # XCode linker dynamically load libLTO.dylib to perform
> > + # link-time optimization.
> > + # http://lists.llvm.org/pipermail/llvm-dev/2009-November/027103.html
> > ^^^^^^^^^^^^^^^^^^^^^^^^
> >
> > + if (NOT TARGET_OS_DARWIN)
> > + # llvm-ar is just a wrapper over ar to pass --plugin= option,
> > + # so that ar can understand LTO objects.
> > + # See https://lists.llvm.org/pipermail/llvm-dev/2018-March/122018.html
> > + set (CMAKE_AR llvm-ar)
> > + endif()
> > + else()
> > + # GNU opts to support lto
> > ^^^^^^^^^^^^^^^^^^^^^^
> >
> > + # Due to some problems (bugs, slow work, etc) we support LTO
> > + # only for 5.0+. The same is for binutils prior to 2.27
> > + # See comments in scripts/Makefile.lto in scope of
> >
> >
> > + # the patch: https://patchwork.kernel.org/patch/10078207/
> > + if (NOT ${CMAKE_CXX_COMPILER_VERSION} VERSION_LESS 5.0
> > + AND NOT ${linker_version} VERSION_LESS 2.27)
> > + set (luajit_cflags ${luajit_cflags} -flto -fuse-linker-plugin -fno-fat-lto-objects)
> > + endif()
> > ^^^^^^^^^^^^^^^^^^^^^^
> > + # gcc-ar is just a wrapper over ar to pass --plugin option
> >
> > Unfortunatlely I have no minimal required version of binutils on my system
> > and I tested patch with ld gold (cmake -DCMAKE_LINKER=/usr/bin/ld.gold ..),
> > as Timur Safin advised.
> >
> > How I tested:
> > $ mkdir build; cd build
> > $ make build_bundled_libs VERBOSE=1 2>&1 | tee log.txt
> >
> > with commands above output in log.txt doesn't contain LTO related options
> > in compilation lines for luajit.
> >
> > gcc 8.3.1, clang 8.0.1, CentOS 8.1.1911
> >
> > Sergey
> >
> > On 17:33 Tue 14 Apr , Olga Arkhangelskaia wrote:
> > > Fixed tabs:
> > >
> > > + # Depending of compiler we need to set appropriate llvm/gcc-ar
> > > lib
> > > + # llvm/gcc -ar is just a wrapper over ar to pass --plugin=
> > > option,
> > > + # so that ar can understand LTO objects.
> > >
> > > 14.04.2020 12:18, Igor Munkin пишет:
> > > > Olya,
> > > >
> > > > Thanks for the patch! I left several comments below, please consider
> > > > them.
> > > >
> > > > On 12.03.20, Olga Arkhangelskaia wrote:
> > > > > Tarantool has LTO support, however while building luajit this opt. was
> > > > > omitted. Patch adds necessary flag to turn it on.
> > > > >
> > > > > Minimum compiler/linker versions: clang 3.4, gcc 5.0+, ld 2.27+.
> > > > >
> > > > > Closes #3743
> > > > > ---
> > > > > Branch: OKriw/gh-3743-LuaJIT-does-not-use-LTO-with-DENABLE_LTO=ON-full-ci
> > > > > cmake/lto.cmake | 3 ++-
> > > > > cmake/luajit.cmake | 26 ++++++++++++++++++++++++++
> > > > > 2 files changed, 28 insertions(+), 1 deletion(-)
> > > > >
> > > > > diff --git a/cmake/lto.cmake b/cmake/lto.cmake
> > > > > index 95ade75f4..9f29f3324 100644
> > > > > --- a/cmake/lto.cmake
> > > > > +++ b/cmake/lto.cmake
> > > > > @@ -78,7 +78,8 @@ if (NOT TARGET_OS_DARWIN)
> > > > > if (linker_version VERSION_LESS "2.31")
> > > > > message(FATAL_ERROR "ld.bfd >= 2.31 is needed for LTO")
> > > > > endif()
> > > > > - elseif(matched_gold)
> > > > > +
> > > > > + elseif(matched_gold)
> > > > Typo: there is a mess with whitespace above.
> > > >
> > > > However this chunk provides no changes except whitespace and newline.
> > > > Please drop it.
> > > >
> > > > > set(linker_version ${CMAKE_MATCH_1})
> > > > > message(STATUS "Found ld.gold version: ${linker_version}")
> > > > > diff --git a/cmake/luajit.cmake b/cmake/luajit.cmake
> > > > > index 072db8269..da1b4926d 100644
> > > > > --- a/cmake/luajit.cmake
> > > > > +++ b/cmake/luajit.cmake
> > > > > @@ -225,6 +225,32 @@ macro(luajit_build)
> > > > > set(luajit_xcflags ${luajit_xcflags} -D${def})
> > > > > endforeach()
> > > > > + # Add LTO option to luajit
> > > > > + if (CMAKE_INTERPROCEDURAL_OPTIMIZATION)
> > > > > + message("Setting LTO flags for building luajit")
> > > > > + # Clang opt to support LTO
> > > > > + if (CMAKE_COMPILER_IS_CLANG AND
> > > > > + NOT ${CMAKE_CXX_COMPILER_VERSION} VERSION_LESS 3.4)
> > > > So, if clang toolchain is used but version is less than 3.4, then gcc
> > > > toolchain settings are used. It's either totally wrong or definitely
> > > > need to be clarified with a corresponding comment.
> > > >
> > > > Also, AFAICS LTO support for toolchain is checked via CheckIPOSupported
> > > > CMake module. So additional check here looks to be excess or also need
> > > > to be clarified.
> > > >
> > > > > + if (${CMAKE_CXX_COMPILER_VERSION} VERSION_LESS 3.9)
> > > > > + set(luajit_cflags ${luajit_cflags} -flto=full)
> > > > > + else()
> > > > > + set(luajit_cflags ${luajit_cflags} -flto=full)
> > > > > + endif()
> > > > I see no difference in the branches above.
> > > >
> > > > > + if (NOT TARGET_OS_DARWIN)
> > > > > + # Depending of compiler we need to set appropriate llvm/gcc-ar lib
> > > > > + set (CMAKE_AR llvm-ar)
> > > > What ar is used on systems different from Darwin based ones when clang
> > > > toolchain is used?
> > > >
> > > > > + endif()
> > > > > + # GNU opts to support lto
> > > > > + else()
> > > > > + #Due to some problems (bugs, slow work, etc) we support LTO only for 5.0+
> > > > > + #The same is for binutils prior 2.27
> > > > > + if (NOT ${CMAKE_CXX_COMPILER_VERSION} VERSION_LESS 5.0
> > > > > + AND NOT ${linker_version} VERSION_LESS 2.27)
> > > > > + set(luajit_cflags ${luajit_cflags} -flto -fuse-linker-plugin -fno-fat-lto-objects)
> > > > > + endif()
> > > > > + set (CMAKE_AR gcc-ar)
> > > > Could you please clarify why ar is set explicitly here?
> > > >
> > > > > + endif()
> > > > > + endif()
> > > > Typo: there is a mess with indent above. Unfortunately I failed to find
> > > > our CMake style guide, so please adjust your changes considering the
> > > > code nearby.
> > > >
> > > > > # Pass the same toolchain that is used for building of
> > > > > # tarantool itself, because tools from different toolchains
> > > > > # can be incompatible. A compiler and a linker are already set
> > > > > --
> > > > > 2.20.1 (Apple Git-117)
> > > > >
--
sergeyb@
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