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<p>Hello Igor,</p>
<p>thanks for the review!<br>
</p>
<div class="moz-cite-prefix">14.04.2020 12:18, Igor Munkin пишет:<br>
</div>
<blockquote type="cite"
cite="mid:20200414091803.GJ5713@tarantool.org">
<pre class="moz-quote-pre" wrap="">Olya,
Thanks for the patch! I left several comments below, please consider
them.
On 12.03.20, Olga Arkhangelskaia wrote:
</pre>
<blockquote type="cite">
<pre class="moz-quote-pre" wrap="">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)
</pre>
</blockquote>
<pre class="moz-quote-pre" wrap="">
Typo: there is a mess with whitespace above.
However this chunk provides no changes except whitespace and newline.
Please drop it.</pre>
</blockquote>
Will fix1<br>
<blockquote type="cite"
cite="mid:20200414091803.GJ5713@tarantool.org">
<pre class="moz-quote-pre" wrap="">
</pre>
<blockquote type="cite">
<pre class="moz-quote-pre" wrap=""> 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 ${CMAKE_CXX_COMPILER_VERSION} VERSION_LESS 3.4)
</pre>
</blockquote>
<pre class="moz-quote-pre" wrap="">
So, if clang toolchain is used but version is less than 3.4, then gcc
toolchain settings are used. It's either totally wrong or definitely
need to be clarified with a corresponding comment.
Also, AFAICS LTO support for toolchain is checked via CheckIPOSupported
CMake module. So additional check here looks to be excess or also need
to be clarified.</pre>
</blockquote>
<p>I have a mistake here (Thin LTO) - will wix it<br>
</p>
<p>If version is above than 3.9 we can use -flto=thin <br>
</p>
<blockquote type="cite"
cite="mid:20200414091803.GJ5713@tarantool.org">
<pre class="moz-quote-pre" wrap="">
</pre>
<blockquote type="cite">
<pre class="moz-quote-pre" wrap="">+ if (${CMAKE_CXX_COMPILER_VERSION} VERSION_LESS 3.9)
+ set(luajit_cflags ${luajit_cflags} -flto=full)
+ else()
+ set(luajit_cflags ${luajit_cflags} -flto=full)
+ endif()
</pre>
</blockquote>
<pre class="moz-quote-pre" wrap="">
I see no difference in the branches above.
</pre>
<blockquote type="cite">
<pre class="moz-quote-pre" wrap="">+ if (NOT TARGET_OS_DARWIN)
+ # Depending of compiler we need to set appropriate llvm/gcc-ar lib
+ set (CMAKE_AR llvm-ar)
</pre>
</blockquote>
<pre class="moz-quote-pre" wrap="">
What ar is used on systems different from Darwin based ones when clang
toolchain is used?</pre>
</blockquote>
<p><br>
</p>
<p>gcc-ar/ llvm-ar is wrapper on ar that simply passes —plugin
option. We need it for LTO.<br>
</p>
<p>( See <a
href="https://bugzilla.redhat.com/show_bug.cgi?id=1678826">https://bugzilla.redhat.com/show_bug.cgi?id=1678826
<br>
</a></p>
<p><a
href="https://lists.llvm.org/pipermail/llvm-dev/2018-March/122018.html">https://lists.llvm.org/pipermail/llvm-dev/2018-March/122018.html)</a></p>
<p><br>
</p>
<blockquote type="cite"
cite="mid:20200414091803.GJ5713@tarantool.org">
<pre class="moz-quote-pre" wrap="">
</pre>
<blockquote type="cite">
<pre class="moz-quote-pre" wrap="">+ 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)
</pre>
</blockquote>
<pre class="moz-quote-pre" wrap="">
Could you please clarify why ar is set explicitly here?</pre>
</blockquote>
<br>
<blockquote type="cite"
cite="mid:20200414091803.GJ5713@tarantool.org">
<pre class="moz-quote-pre" wrap="">
</pre>
<blockquote type="cite">
<pre class="moz-quote-pre" wrap="">+ endif()
+ endif()
</pre>
</blockquote>
<pre class="moz-quote-pre" wrap="">
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.</pre>
</blockquote>
Will fix<br>
<blockquote type="cite"
cite="mid:20200414091803.GJ5713@tarantool.org">
<pre class="moz-quote-pre" wrap="">
</pre>
<blockquote type="cite">
<pre class="moz-quote-pre" wrap=""> # 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)
</pre>
</blockquote>
<pre class="moz-quote-pre" wrap="">
</pre>
</blockquote>
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