[llvm-dev] (Thin)LTO llvm build

[Teresa Johnson via llvm-dev]

I can't reproduce the failure. I am building with a clang built Release
from recent source as my stage-1 bootstrap compiler:
   clang version 4.0.0 (trunk 282322) (llvm/trunk 282341)

I am configuring the stage-2 bootstrap compiler with the following command,
which largely is copied from your earlier email with your cmake command
(changes noted below):

  lto=Thin
  type=Release
  cflgs=-w
  INSTALL_PREFIX=$HOME/llvm/${build_dir_name}/clang-install
  BUILD_COMPILER=$HOME/llvm/llvm_10_release_build
  SRC=$HOME/llvm/llvm_head
  BINUTILS=$HOME/binutils/binutils
  env DYLD_LIBRARY_PATH=$BUILD_COMPILER/lib/ \
  cmake \
    -G Ninja \
    -DCMAKE_BUILD_TYPE=${type} \
    -DLLVM_BINUTILS_INCDIR=$BINUTILS/include \
    -DCMAKE_INSTALL_PREFIX=$INSTALL_PREFIX \
    -DLLVM_TARGETS_TO_BUILD="X86" \
    -DLLVM_ENABLE_BACKTRACES=OFF \
    -DLLVM_BUILD_EXAMPLES=OFF \
    -DLLVM_INCLUDE_EXAMPLES=OFF \
    -DLLVM_BUILD_TESTS=OFF \
    -DLLVM_INCLUDE_TESTS=OFF \
    -DLLVM_BUILD_DOCS=OFF \
    -DLLVM_INCLUDE_DOCS=OFF \
    -DLLVM_ENABLE_DOXYGEN=OFF \
    -DLLVM_ENABLE_SPHINX=OFF \
    -DLLDB_DISABLE_PYTHON=ON \
    -DCLANG_PLUGIN_SUPPORT=OFF \
    -DLLVM_ENABLE_LTO=${lto} \
    -DCMAKE_C_COMPILER=$BUILD_COMPILER/bin/clang \
    -DCMAKE_CXX_COMPILER=$BUILD_COMPILER/bin/clang++ \
    -DCMAKE_AR=$BUILD_COMPILER/bin/llvm-ar \
    -DCMAKE_RANLIB=$BUILD_COMPILER/bin/llvm-ranlib \
    -DLLVM_PARALLEL_LINK_JOBS=1 \
    -DBUILD_SHARED_LIBS=ON \
    -DCMAKE_C_FLAGS=${cflgs} \
    -DCMAKE_CXX_FLAGS=${cflgs} \
    -DCMAKE_EXE_LINKER_FLAGS=${linkflgs} \
    $SRC

The changes from your config:
1) Used llvm-ar and llvm-nm from the build compiler. I noticed that you are
specifying those as coming from the same directory used for
CMAKE_INSTALL_PREFIX, which seems wrong - that is where the compiler built
here will be installed.
2) Used my own binutils checkout as I don't have plugin-api.h installed in
/usr/include
3) Set BUILD_SHARED_LIBS=ON (which I don't see in your earlier config, did
you add that later?)
4) Set LLVM_PARALLEL_LINK_JOBS=1 (probably not needed)
5) Build with -w, to avoid occasional issues with warnings only emitted by
clang (probably not needed)
6) Specified CMAKE_C_COMPILER and CMAKE_CXX_COMPILER explicitly (you might
have had the right versions in your path?)

I did an nm on the .so libraries to see where __morestack was referenced
and its linkage. No surprise, it is coming from libLLVMRuntimeDyld.so, and
I do see it as weak as expected:

$ nm lib/libLLVMRuntimeDyld.so | grep morestack
                 w __morestack

Can you do the above nm on your lib/libLLVMRuntimeDyld.so and send me the
output?

Thanks,
Teresa

On Tue, Sep 27, 2016 at 7:00 AM, Teresa Johnson <tejohnson at google.com>
wrote:

>
>
> On Tue, Sep 27, 2016 at 6:53 AM, Mehdi Amini <mehdi.amini at apple.com>
> wrote:
>
>>
>>
>> > On Sep 27, 2016, at 2:18 AM, Carsten Mattner <carstenmattner at gmail.com>
>> wrote:
>> >
>> >> On Mon, Sep 26, 2016 at 11:02 PM, Teresa Johnson <tejohnson at google.com>
>> wrote:
>> >> I'll either need to get a reproducer from you and/or try to repro it
>> myself.
>> >
>> > Assuming I run into this with BUILD_SHARED_LIBS=OFF, which seems
>> unlikely,
>> > what kind of reproducer data would you need from me?
>>
>
> Let me see if I can reproduce it first. Probably a zip of all the inputs
> to the link and the link command line. Another option would be to save the
> temp files, but it would require some work to find the one producing the
> error and I might need all the inputs anyway...
>
>
>> >
>> >> I usually don't check out and build lldb, so perhaps I will start with
>> that.
>> >
>> > I must say I'm surprised a ThinLTO build of all of LLVM svn isn't part
>> of
>> > the periodic builders.
>>
>>
>> I have one, it just does include LLDB.
>>
>
> Great, I was going to ask how to get one set up. Is it an official build
> bot? And I assume you meant it just does "not" include LLDB?
>
> Working getting a shared build of LLDB right now...
>
> Teresa
>
>
>> Mehdi
>> >
>> >> As a workaround you could try -DBUILD_SHARED_LIBS=OFF.
>> >
>> > Thanks, will do, but probably not before Wednesday because it looks like
>> > this requires a full rebuild, if my interpretation of the cmake
>> warning/error
>> > is correct.
>>
>
>
>
> --
> Teresa Johnson |  Software Engineer |  tejohnson at google.com |
> 408-460-2413
>



-- 
Teresa Johnson |  Software Engineer |  tejohnson at google.com |  408-460-2413
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