Re: [Boost-users] [Boost.Math] Weird compiler-error with Clang 3.8

Subject: Re: [Boost-users] [Boost.Math] Weird compiler-error with Clang 3.8
From: Deniz Bahadir (dbahadir_at_[hidden])
Date: 2017-01-19 09:27:14

Am 18.01.2017 um 18:00 schrieb John Maddock:
>
>
> On 18/01/2017 13:25, Deniz Bahadir wrote:
>> Hi guys,
>>
>> Our build-server (Jenkins) tried to build Boost 1.58 with Clang 3.8
>> and libc++ and tripped over an error that I do not understand.
>> Maybe someone can shed some light on it?

I can, now.

>
> A probable workaround is to build with pch=off, but I don't understand
> the error either, it's something to do with your specific version of
> clang not understanding the command line (which I believe is the same as
> for gcc, so it should work?)

Actually, these lines look quite different.

from gcc.jam:
   "$(CONFIG_COMMAND)" -x c++-header $(OPTIONS) $(USER_OPTIONS) 
-D$(DEFINES) -I"$(INCLUDES)" -c -o "$(<)" "$(>)"

from clang-linux.jam:
   rm -f "$(<)" && "$(CONFIG_COMMAND)" -x c++-header $(OPTIONS) 
$(USER_OPTIONS) -D$(DEFINES) -I"$(INCLUDES)" -Xclang -emit-pth -o "$(<)" 
"$(>)"

Note the "-c" option which is there in the GCC command but missing in 
the Clang command?
With it missing, Clang seems to try to generate pre-compiled headers and 
link them (to what?) which would generate multiple output files. 
Therefore the error-message.

BTW, this is not only true for Boost.Build command 
"clang-linux.compile.c++.pch" but also for "clang-linux.compiler.c.pch".

After I added the "-c" option to both commands, it compiles fine.

A patch for the 1.58.0 release is attached.
Should I create a pull-request to Boost.Build with this fix?

>
> Everything works fine for me with my clang version on Ubuntu BTW, but if
> you can figure out what the issue with the command line is, we might be
> able to fix it in the build scripts.
>

I am wondering why your Clang version seems to work fine. I tested Clang 
3.8 and Clang 3.7 and both fail with the "-c" option missing.

However, just a few days ago I was able to compile everything with Clang 
3.8 without any problems!?
However, some linker-options changed since then. (I added "-lc++abi" and 
"-Wl,--as-needed".) And some updates where installed to the Ubuntu OS...
So I cannot really tell what made the difference.

> HTH, John.
>

Thanks,
Deniz

>>
>> The specific error is this:
>>
>> clang-linux.compile.c++.pch
>> /home/jenkins/workspace/Pipeline_Boost_at_3/clang38/build/boost/boost/bin.v2/libs/math/build/clang-linux-3.8/release/threading-multi/../src/tr1/pch.hpp.pth
>>
>> clang: error: cannot specify -o when generating multiple output files
>>
>> Does this look familiar to anyone?
>>
>> My build-environment is Ubuntu 16.04 x86_64 and I invoked Boost.Build
>> like this:
>>
>>
>> cd /home/jenkins/workspace/Pipeline_Boost/sources/boost_1_58_0
>> COMMON_COMPILER_FLAGS="-m64 -fpic -fdiagnostics-color=always -O3"
>> CFLAGS="$COMMON_COMPILER_FLAGS"
>> CXXFLAGS="$COMMON_COMPILER_FLAGS -std=c++14 -stdlib=libc++
>> -isystem/usr/include/libcxxabi -lc++abi"
>> CC=/usr/bin/clang-3.8
>> CXX=/usr/bin/clang++-3.8
>>
>> /home/jenkins/workspace/Pipeline_Boost_at_3/clang38/build/boost-build/b2
>> -j1 -q  \
>>
>> --build-dir=/home/jenkins/workspace/Pipeline_Boost_at_3/clang38/build/boost
>> \
>>     --build-type=minimal --layout=versioned address-model=64 install  \
>>
>> --prefix=/home/jenkins/workspace/Pipeline_Boost_at_3/clang38/installed/opt/BENOCS/clang38
>>  \
>>
>> --libdir=/home/jenkins/workspace/Pipeline_Boost_at_3/clang38/installed/opt/BENOCS/clang38/lib/x86_64-linux-gnu
>>  \
>>     dll-path==/opt/BENOCS/clang38/lib/x86_64-linux-gnu  \
>>     toolset=clang-3.8  \
>>     cflags="$CFLAGS" CXXFLAGS="$CXXFLAGS" linkflags="-Wl,--as-needed"
>>
>>
>> The more detailed error-message is the following:
>>
>>
>> common.mkdir
>> /home/jenkins/workspace/Pipeline_Boost_at_3/clang38/build/boost/boost/bin.v2/libs/math/build
>>
>> common.mkdir
>> /home/jenkins/workspace/Pipeline_Boost_at_3/clang38/build/boost/boost/bin.v2/libs/math/build/clang-linux-3.8
>>
>> common.mkdir
>> /home/jenkins/workspace/Pipeline_Boost_at_3/clang38/build/boost/boost/bin.v2/libs/math/build/clang-linux-3.8/release
>>
>> common.mkdir
>> /home/jenkins/workspace/Pipeline_Boost_at_3/clang38/build/boost/boost/bin.v2/libs/math/build/clang-linux-3.8/release/threading-multi
>>
>> common.mkdir
>> /home/jenkins/workspace/Pipeline_Boost_at_3/clang38/build/boost/boost/bin.v2/libs/math/build/clang-linux-3.8/release/threading-multi/..
>>
>> common.mkdir
>> /home/jenkins/workspace/Pipeline_Boost_at_3/clang38/build/boost/boost/bin.v2/libs/math/build/clang-linux-3.8/release/threading-multi/../src
>>
>> common.mkdir
>> /home/jenkins/workspace/Pipeline_Boost_at_3/clang38/build/boost/boost/bin.v2/libs/math/build/clang-linux-3.8/release/threading-multi/../src/tr1
>>
>> clang-linux.compile.c++.pch
>> /home/jenkins/workspace/Pipeline_Boost_at_3/clang38/build/boost/boost/bin.v2/libs/math/build/clang-linux-3.8/release/threading-multi/../src/tr1/pch.hpp.pth
>>
>> clang: error: cannot specify -o when generating multiple output files
>>
>>   rm -f
>> "/home/jenkins/workspace/Pipeline_Boost_at_3/clang38/build/boost/boost/bin.v2/libs/math/build/clang-linux-3.8/release/threading-multi/../src/tr1/pch.hpp.pth"
>> && "clang++" -x c++-header -m64 -fpic -fdiagnostics-color=always -O3
>> -std=c++14 -stdlib=libc++ -isystem/usr/include/libcxxabi -lc++abi -m64
>> -fpic -fdiagnostics-color=always -O3   -O3 -Wno-inline -Wall -pthread
>> -fPIC -m64 -m64 -fpic -fdiagnostics-color=always -O3 -std=c++14
>> -stdlib=libc++ -isystem/usr/include/libcxxabi -lc++abi -m64 -fpic
>> -fdiagnostics-color=always -O3   -DBOOST_ALL_NO_LIB=1
>> -DBOOST_BUILD_PCH_ENABLED -DBOOST_MATH_TR1_DYN_LINK=1 -DNDEBUG -I"."
>> -I"libs/math/src/tr1" -Xclang -emit-pth -o
>> "/home/jenkins/workspace/Pipeline_Boost_at_3/clang38/build/boost/boost/bin.v2/libs/math/build/clang-linux-3.8/release/threading-multi/../src/tr1/pch.hpp.pth"
>> "libs/math/build/../src/tr1/pch.hpp"
>>
>> ...failed clang-linux.compile.c++.pch
>> /home/jenkins/workspace/Pipeline_Boost_at_3/clang38/build/boost/boost/bin.v2/libs/math/build/clang-linux-3.8/release/threading-multi/../src/tr1/pch.hpp.pth...
>>
>> ...skipped
>> <p/home/jenkins/workspace/Pipeline_Boost_at_3/clang38/build/boost/boost/bin.v2/libs/math/build/clang-linux-3.8/release/threading-multi>assoc_laguerre.o
>> for lack of
>> <p/home/jenkins/workspace/Pipeline_Boost_at_3/clang38/build/boost/boost/bin.v2/libs/math/build/clang-linux-3.8/release/threading-multi>../src/tr1/pch.hpp.pth...
>>
>> ...failed updating 1 target...
>> ...skipped 1 target...
>> ...updated 11871 targets...
>>
>>
>> Can someone tell me what is going on and how to fix or work around
>> this problem?
>>
>> Thanks,
>> Deniz
>>
>
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