llvm dev - May 2016 - Undefined symbols in llvm-objdump linkage on x86_64-apple-darwin15

On Tue, May 24, 2016 at 2:28 PM, Chris Bieneman <beanz at apple.com>
wrote:
> Jack,
>
> What version of CMake are you using?
>
> -Chris
Chris,
      I am using cmake 3.5.2. My read of this problem is as follows.
While libLLVM.dylib is being linked against -lxar when
-DLLVM_LINK_LLVM_DYLIB:BOOL=ON is passed to cmake, the libLLVM.dylib
is created with -Wl,-dead_strip such that any symbols from libxar not
explicitly used with in the object files of libLLVM.dylib are stripped
out. This means that those additional symbols used by llvm-objdump
aren't accessible from libLLVM.dylib's linkage on libxar and an
additional explicit linkage on libxar is required in the
tools/llvm-objdump/CMakeLists.txt when HAVE_LIBXAR and
LLVM_LINK_LLVM_DYLIB are set.
        Jack
>
>> On May 24, 2016, at 11:00 AM, Jack Howarth <howarth.mailing.lists at
gmail.com> wrote:
>>
>> On Tue, May 24, 2016 at 1:35 PM, Kevin Enderby <enderby at
apple.com> wrote:
>>> Hi Jack,
>>>
>>> Just a guess here, this may be the bug Chris helped me out with in
the use of the include file xar/xar.h which is not C++ safe.  I needed to wrap
my include via:
>>>
>>> #ifdef HAVE_LIBXAR
>>> extern "C" {
>>> #include <xar/xar.h>
>>> }
>>> #endif
>>>
>>> I think we may need some help from Chris to track this down.  I’ll
bug him in a bit to see if he can help us on this.
>>
>> While the build here with  -DLLVM_LINK_LLVM_DYLIB:BOOL=ON passed on
>> the cmake options produces HAVE_LIBXAR:INTERNAL=1 in CMakeCache.txt, I
>> don't see anything in the cmakefiles for tools/llvm-objdump to
provide
>> the necessary linkage on the system libxar shared library. Appending
>> the missing linkage for -lxar onto
>> build/stage1tools/llvm-objdump/CMakeFiles/llvm-objdump.dir/link.txt...
>>
>> /sw/src/fink.build/llvm39-3.9.0-1/opt-bin/ccclang++   -fno-common
>> -fPIC -fvisibility-inlines-hidden -Wall -W -Wno-unused-parameter
>> -Wwrite-strings -Wcast-qual -Wmissing-field-initializers -pedantic
>> -Wno-long-long -Wcovered-switch-default -Wnon-virtual-dtor
>> -Wdelete-non-virtual-dtor -Werror=date-time -std=c++11 -O3
>> -Wl,-search_paths_first -Wl,-headerpad_max_install_names  -L/sw/lib
>> -Wl,-dead_strip CMakeFiles/llvm-objdump.dir/llvm-objdump.cpp.o
>> CMakeFiles/llvm-objdump.dir/COFFDump.cpp.o
>> CMakeFiles/llvm-objdump.dir/ELFDump.cpp.o
>> CMakeFiles/llvm-objdump.dir/MachODump.cpp.o  -o ../../bin/llvm-objdump
>> ../../lib/libLLVM.dylib -Wl,-rpath, at executable_path/../lib -lxar
>>
>> eliminates the bootstrap failure.
>>
>>>
>>> Kev
>>>
>>>> On May 24, 2016, at 10:28 AM, Jack Howarth
<howarth.mailing.lists at gmail.com> wrote:
>>>>
>>>> On Tue, May 24, 2016 at 1:24 PM, Jack Howarth
>>>> <howarth.mailing.lists at gmail.com> wrote:
>>>>> On Tue, May 24, 2016 at 1:22 PM, Jack Howarth
>>>>> <howarth.mailing.lists at gmail.com> wrote:
>>>>>> On Tue, May 24, 2016 at 12:08 PM, Reid Kleckner <rnk
at google.com> wrote:
>>>>>>> Kevin Enderby added those symbol uses in r270491.
It has a cmake
>>>>>>> feature test, and all the uses of those symbols
appear bracketed in
>>>>>>> HAVE_LIBXAR, so I don't know what went wrong
for you.
>>>>>>
>>>>>> The trigger for this build failure is the usage of
>>>>>> -DLLVM_BUILD_EXTERNAL_COMPILER_RT:BOOL=ON. If I drop
that cmake
>>>>>> option, the linkage failure for llvm-objdump
disappears.
>>>>>
>>>>> Wrong cmake option. I meant to say that
-DLLVM_LINK_LLVM_DYLIB:BOOL=ON
>>>>> is the trigger of the build failure. Sorry for the noise
there.
>>>>
>>>> Filed as https://llvm.org/bugs/show_bug.cgi?id=27855
>>>>
>>>>>
>>>>>>
>>>>>>>
>>>>>>> On Tue, May 24, 2016 at 8:07 AM, Jack Howarth via
llvm-dev
>>>>>>> <llvm-dev at lists.llvm.org> wrote:
>>>>>>>> Is anyone else seeing a bootstrap failure on
x86_64-apple-darwin15 in
>>>>>>>> current trunk?
>>>>>>>>
>>>>>>>> [ 95%] Linking CXX executable
../../bin/llvm-objdump
>>>>>>>> Undefined symbols for architecture x86_64:
>>>>>>>> "_xar_serialize", referenced from:
>>>>>>>>    
DumpBitcodeSection(llvm::object::MachOObjectFile*, char const*,
>>>>>>>> unsigned int, bool, bool, bool,
std::__1::basic_string<char,
>>>>>>>> std::__1::char_traits<char>,
std::__1::allocator<char> >) in
>>>>>>>> MachODump.cpp.o
>>>>>>>> "_xar_file_first", referenced from:
>>>>>>>>    
DumpBitcodeSection(llvm::object::MachOObjectFile*, char const*,
>>>>>>>> unsigned int, bool, bool, bool,
std::__1::basic_string<char,
>>>>>>>> std::__1::char_traits<char>,
std::__1::allocator<char> >) in
>>>>>>>> MachODump.cpp.o
>>>>>>>> "_xar_iter_new", referenced from:
>>>>>>>>    
DumpBitcodeSection(llvm::object::MachOObjectFile*, char const*,
>>>>>>>> unsigned int, bool, bool, bool,
std::__1::basic_string<char,
>>>>>>>> std::__1::char_traits<char>,
std::__1::allocator<char> >) in
>>>>>>>> MachODump.cpp.o
>>>>>>>> "_xar_prop_first", referenced from:
>>>>>>>>    
DumpBitcodeSection(llvm::object::MachOObjectFile*, char const*,
>>>>>>>> unsigned int, bool, bool, bool,
std::__1::basic_string<char,
>>>>>>>> std::__1::char_traits<char>,
std::__1::allocator<char> >) in
>>>>>>>> MachODump.cpp.o
>>>>>>>> "_xar_extract_tobuffersz", referenced
from:
>>>>>>>>    
DumpBitcodeSection(llvm::object::MachOObjectFile*, char const*,
>>>>>>>> unsigned int, bool, bool, bool,
std::__1::basic_string<char,
>>>>>>>> std::__1::char_traits<char>,
std::__1::allocator<char> >) in
>>>>>>>> MachODump.cpp.o
>>>>>>>> "_xar_open", referenced from:
>>>>>>>>    
DumpBitcodeSection(llvm::object::MachOObjectFile*, char const*,
>>>>>>>> unsigned int, bool, bool, bool,
std::__1::basic_string<char,
>>>>>>>> std::__1::char_traits<char>,
std::__1::allocator<char> >) in
>>>>>>>> MachODump.cpp.o
>>>>>>>> "_xar_prop_get", referenced from:
>>>>>>>>    
DumpBitcodeSection(llvm::object::MachOObjectFile*, char const*,
>>>>>>>> unsigned int, bool, bool, bool,
std::__1::basic_string<char,
>>>>>>>> std::__1::char_traits<char>,
std::__1::allocator<char> >) in
>>>>>>>> MachODump.cpp.o
>>>>>>>> "_xar_close", referenced from:
>>>>>>>>    
DumpBitcodeSection(llvm::object::MachOObjectFile*, char const*,
>>>>>>>> unsigned int, bool, bool, bool,
std::__1::basic_string<char,
>>>>>>>> std::__1::char_traits<char>,
std::__1::allocator<char> >) in
>>>>>>>> MachODump.cpp.o
>>>>>>>> "_xar_prop_next", referenced from:
>>>>>>>>    
DumpBitcodeSection(llvm::object::MachOObjectFile*, char const*,
>>>>>>>> unsigned int, bool, bool, bool,
std::__1::basic_string<char,
>>>>>>>> std::__1::char_traits<char>,
std::__1::allocator<char> >) in
>>>>>>>> MachODump.cpp.o
>>>>>>>> "_xar_iter_free", referenced from:
>>>>>>>>    
DumpBitcodeSection(llvm::object::MachOObjectFile*, char const*,
>>>>>>>> unsigned int, bool, bool, bool,
std::__1::basic_string<char,
>>>>>>>> std::__1::char_traits<char>,
std::__1::allocator<char> >) in
>>>>>>>> MachODump.cpp.o
>>>>>>>> "_xar_file_next", referenced from:
>>>>>>>>    
DumpBitcodeSection(llvm::object::MachOObjectFile*, char const*,
>>>>>>>> unsigned int, bool, bool, bool,
std::__1::basic_string<char,
>>>>>>>> std::__1::char_traits<char>,
std::__1::allocator<char> >) in
>>>>>>>> MachODump.cpp.o
>>>>>>>> ld: symbol(s) not found for architecture x86_64
>>>>>>>> clang: error: linker command failed with exit
code 1 (use -v to see invocation)
>>>>>>>>
tools/llvm-objdump/CMakeFiles/llvm-objdump.dir/build.make:173: recipe
>>>>>>>> for target 'bin/llvm-objdump' failed
>>>>>>>> make[2]: *** [bin/llvm-objdump] Error 1
>>>>>>>> make[2]: Target
'tools/llvm-objdump/CMakeFiles/llvm-objdump.dir/build'
>>>>>>>> not remade because of errors.
>>>>>>>> CMakeFiles/Makefile2:21861: recipe for target
>>>>>>>>
'tools/llvm-objdump/CMakeFiles/llvm-objdump.dir/all' failed
>>>>>>>> make[1]: ***
[tools/llvm-objdump/CMakeFiles/llvm-objdump.dir/all] Error 2
>>>>>>>> _______________________________________________
>>>>>>>> LLVM Developers mailing list
>>>>>>>> llvm-dev at lists.llvm.org
>>>>>>>>
http://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-dev
>>>
>

On Tue, May 24, 2016 at 2:37 PM, Jack Howarth
<howarth.mailing.lists at gmail.com> wrote:
> On Tue, May 24, 2016 at 2:28 PM, Chris Bieneman <beanz at apple.com>
wrote:
>> Jack,
>>
>> What version of CMake are you using?
>>
>> -Chris
>
> Chris,
>       I am using cmake 3.5.2. My read of this problem is as follows.
> While libLLVM.dylib is being linked against -lxar when
> -DLLVM_LINK_LLVM_DYLIB:BOOL=ON is passed to cmake, the libLLVM.dylib
> is created with -Wl,-dead_strip such that any symbols from libxar not
> explicitly used with in the object files of libLLVM.dylib are stripped
> out. This means that those additional symbols used by llvm-objdump
> aren't accessible from libLLVM.dylib's linkage on libxar and an
> additional explicit linkage on libxar is required in the
> tools/llvm-objdump/CMakeLists.txt when HAVE_LIBXAR and
> LLVM_LINK_LLVM_DYLIB are set.
>         Jack
Also note that this issue doesn't arise for the cmake build with
-DBUILD_SHARED_LIBS:BOOL=ON because the resulting
lib/Object/CMakeFiles/LLVMObject.dir/link.txt contains...

/sw/src/fink.build/llvm39-3.9.0-1/opt-bin/ccclang++  -fno-common -fPIC
-fvisibility-inlines-hidden -Wall -W -Wno-unused-parameter
-Wwrite-strings -Wcast-qual -Wmissing-field-initializers -pedantic
-Wno-long-long -Wcovered-switch-default -Wnon-virtual-dtor
-Wdelete-non-virtual-dtor -Werror=date-time -std=c++11 -O3 -dynamiclib
-Wl,-headerpad_max_install_names  -Wl,-dead_strip  -L/sw/lib -o
../libLLVMObject.dylib -install_name @rpath/libLLVMObject.dylib
CMakeFiles/LLVMObject.dir/Archive.cpp.o
CMakeFiles/LLVMObject.dir/ArchiveWriter.cpp.o
CMakeFiles/LLVMObject.dir/Binary.cpp.o
CMakeFiles/LLVMObject.dir/COFFObjectFile.cpp.o
CMakeFiles/LLVMObject.dir/ELF.cpp.o
CMakeFiles/LLVMObject.dir/ELFObjectFile.cpp.o
CMakeFiles/LLVMObject.dir/Error.cpp.o
CMakeFiles/LLVMObject.dir/IRObjectFile.cpp.o
CMakeFiles/LLVMObject.dir/MachOObjectFile.cpp.o
CMakeFiles/LLVMObject.dir/MachOUniversal.cpp.o
CMakeFiles/LLVMObject.dir/ModuleSummaryIndexObjectFile.cpp.o
CMakeFiles/LLVMObject.dir/Object.cpp.o
CMakeFiles/LLVMObject.dir/ObjectFile.cpp.o
CMakeFiles/LLVMObject.dir/RecordStreamer.cpp.o
CMakeFiles/LLVMObject.dir/SymbolicFile.cpp.o
CMakeFiles/LLVMObject.dir/SymbolSize.cpp.o -lxar
../libLLVMBitReader.dylib ../libLLVMCore.dylib ../libLLVMMC.dylib
../libLLVMMCParser.dylib ../libLLVMSupport.dylib
-Wl,-rpath, at executable_path/../lib

and thus the linkage for  llvm-objdump is directly linked against
libxar as in the default static lib build. Only the
-DLLVM_LINK_LLVM_DYLIB:BOOL=ON build attempts to resolve the symbols
from libxar using an indirect linkage on libxar in libLLVM.dylib.
               Jack
>>
>>> On May 24, 2016, at 11:00 AM, Jack Howarth
<howarth.mailing.lists at gmail.com> wrote:
>>>
>>> On Tue, May 24, 2016 at 1:35 PM, Kevin Enderby <enderby at
apple.com> wrote:
>>>> Hi Jack,
>>>>
>>>> Just a guess here, this may be the bug Chris helped me out with
in the use of the include file xar/xar.h which is not C++ safe.  I needed to
wrap my include via:
>>>>
>>>> #ifdef HAVE_LIBXAR
>>>> extern "C" {
>>>> #include <xar/xar.h>
>>>> }
>>>> #endif
>>>>
>>>> I think we may need some help from Chris to track this down. 
I’ll bug him in a bit to see if he can help us on this.
>>>
>>> While the build here with  -DLLVM_LINK_LLVM_DYLIB:BOOL=ON passed on
>>> the cmake options produces HAVE_LIBXAR:INTERNAL=1 in
CMakeCache.txt, I
>>> don't see anything in the cmakefiles for tools/llvm-objdump to
provide
>>> the necessary linkage on the system libxar shared library.
Appending
>>> the missing linkage for -lxar onto
>>>
build/stage1tools/llvm-objdump/CMakeFiles/llvm-objdump.dir/link.txt...
>>>
>>> /sw/src/fink.build/llvm39-3.9.0-1/opt-bin/ccclang++   -fno-common
>>> -fPIC -fvisibility-inlines-hidden -Wall -W -Wno-unused-parameter
>>> -Wwrite-strings -Wcast-qual -Wmissing-field-initializers -pedantic
>>> -Wno-long-long -Wcovered-switch-default -Wnon-virtual-dtor
>>> -Wdelete-non-virtual-dtor -Werror=date-time -std=c++11 -O3
>>> -Wl,-search_paths_first -Wl,-headerpad_max_install_names  -L/sw/lib
>>> -Wl,-dead_strip CMakeFiles/llvm-objdump.dir/llvm-objdump.cpp.o
>>> CMakeFiles/llvm-objdump.dir/COFFDump.cpp.o
>>> CMakeFiles/llvm-objdump.dir/ELFDump.cpp.o
>>> CMakeFiles/llvm-objdump.dir/MachODump.cpp.o  -o
../../bin/llvm-objdump
>>> ../../lib/libLLVM.dylib -Wl,-rpath, at executable_path/../lib -lxar
>>>
>>> eliminates the bootstrap failure.
>>>
>>>>
>>>> Kev
>>>>
>>>>> On May 24, 2016, at 10:28 AM, Jack Howarth
<howarth.mailing.lists at gmail.com> wrote:
>>>>>
>>>>> On Tue, May 24, 2016 at 1:24 PM, Jack Howarth
>>>>> <howarth.mailing.lists at gmail.com> wrote:
>>>>>> On Tue, May 24, 2016 at 1:22 PM, Jack Howarth
>>>>>> <howarth.mailing.lists at gmail.com> wrote:
>>>>>>> On Tue, May 24, 2016 at 12:08 PM, Reid Kleckner
<rnk at google.com> wrote:
>>>>>>>> Kevin Enderby added those symbol uses in
r270491. It has a cmake
>>>>>>>> feature test, and all the uses of those symbols
appear bracketed in
>>>>>>>> HAVE_LIBXAR, so I don't know what went
wrong for you.
>>>>>>>
>>>>>>> The trigger for this build failure is the usage of
>>>>>>> -DLLVM_BUILD_EXTERNAL_COMPILER_RT:BOOL=ON. If I
drop that cmake
>>>>>>> option, the linkage failure for llvm-objdump
disappears.
>>>>>>
>>>>>> Wrong cmake option. I meant to say that
-DLLVM_LINK_LLVM_DYLIB:BOOL=ON
>>>>>> is the trigger of the build failure. Sorry for the
noise there.
>>>>>
>>>>> Filed as https://llvm.org/bugs/show_bug.cgi?id=27855
>>>>>
>>>>>>
>>>>>>>
>>>>>>>>
>>>>>>>> On Tue, May 24, 2016 at 8:07 AM, Jack Howarth
via llvm-dev
>>>>>>>> <llvm-dev at lists.llvm.org> wrote:
>>>>>>>>> Is anyone else seeing a bootstrap failure
on x86_64-apple-darwin15 in
>>>>>>>>> current trunk?
>>>>>>>>>
>>>>>>>>> [ 95%] Linking CXX executable
../../bin/llvm-objdump
>>>>>>>>> Undefined symbols for architecture x86_64:
>>>>>>>>> "_xar_serialize", referenced
from:
>>>>>>>>>    
DumpBitcodeSection(llvm::object::MachOObjectFile*, char const*,
>>>>>>>>> unsigned int, bool, bool, bool,
std::__1::basic_string<char,
>>>>>>>>> std::__1::char_traits<char>,
std::__1::allocator<char> >) in
>>>>>>>>> MachODump.cpp.o
>>>>>>>>> "_xar_file_first", referenced
from:
>>>>>>>>>    
DumpBitcodeSection(llvm::object::MachOObjectFile*, char const*,
>>>>>>>>> unsigned int, bool, bool, bool,
std::__1::basic_string<char,
>>>>>>>>> std::__1::char_traits<char>,
std::__1::allocator<char> >) in
>>>>>>>>> MachODump.cpp.o
>>>>>>>>> "_xar_iter_new", referenced from:
>>>>>>>>>    
DumpBitcodeSection(llvm::object::MachOObjectFile*, char const*,
>>>>>>>>> unsigned int, bool, bool, bool,
std::__1::basic_string<char,
>>>>>>>>> std::__1::char_traits<char>,
std::__1::allocator<char> >) in
>>>>>>>>> MachODump.cpp.o
>>>>>>>>> "_xar_prop_first", referenced
from:
>>>>>>>>>    
DumpBitcodeSection(llvm::object::MachOObjectFile*, char const*,
>>>>>>>>> unsigned int, bool, bool, bool,
std::__1::basic_string<char,
>>>>>>>>> std::__1::char_traits<char>,
std::__1::allocator<char> >) in
>>>>>>>>> MachODump.cpp.o
>>>>>>>>> "_xar_extract_tobuffersz",
referenced from:
>>>>>>>>>    
DumpBitcodeSection(llvm::object::MachOObjectFile*, char const*,
>>>>>>>>> unsigned int, bool, bool, bool,
std::__1::basic_string<char,
>>>>>>>>> std::__1::char_traits<char>,
std::__1::allocator<char> >) in
>>>>>>>>> MachODump.cpp.o
>>>>>>>>> "_xar_open", referenced from:
>>>>>>>>>    
DumpBitcodeSection(llvm::object::MachOObjectFile*, char const*,
>>>>>>>>> unsigned int, bool, bool, bool,
std::__1::basic_string<char,
>>>>>>>>> std::__1::char_traits<char>,
std::__1::allocator<char> >) in
>>>>>>>>> MachODump.cpp.o
>>>>>>>>> "_xar_prop_get", referenced from:
>>>>>>>>>    
DumpBitcodeSection(llvm::object::MachOObjectFile*, char const*,
>>>>>>>>> unsigned int, bool, bool, bool,
std::__1::basic_string<char,
>>>>>>>>> std::__1::char_traits<char>,
std::__1::allocator<char> >) in
>>>>>>>>> MachODump.cpp.o
>>>>>>>>> "_xar_close", referenced from:
>>>>>>>>>    
DumpBitcodeSection(llvm::object::MachOObjectFile*, char const*,
>>>>>>>>> unsigned int, bool, bool, bool,
std::__1::basic_string<char,
>>>>>>>>> std::__1::char_traits<char>,
std::__1::allocator<char> >) in
>>>>>>>>> MachODump.cpp.o
>>>>>>>>> "_xar_prop_next", referenced
from:
>>>>>>>>>    
DumpBitcodeSection(llvm::object::MachOObjectFile*, char const*,
>>>>>>>>> unsigned int, bool, bool, bool,
std::__1::basic_string<char,
>>>>>>>>> std::__1::char_traits<char>,
std::__1::allocator<char> >) in
>>>>>>>>> MachODump.cpp.o
>>>>>>>>> "_xar_iter_free", referenced
from:
>>>>>>>>>    
DumpBitcodeSection(llvm::object::MachOObjectFile*, char const*,
>>>>>>>>> unsigned int, bool, bool, bool,
std::__1::basic_string<char,
>>>>>>>>> std::__1::char_traits<char>,
std::__1::allocator<char> >) in
>>>>>>>>> MachODump.cpp.o
>>>>>>>>> "_xar_file_next", referenced
from:
>>>>>>>>>    
DumpBitcodeSection(llvm::object::MachOObjectFile*, char const*,
>>>>>>>>> unsigned int, bool, bool, bool,
std::__1::basic_string<char,
>>>>>>>>> std::__1::char_traits<char>,
std::__1::allocator<char> >) in
>>>>>>>>> MachODump.cpp.o
>>>>>>>>> ld: symbol(s) not found for architecture
x86_64
>>>>>>>>> clang: error: linker command failed with
exit code 1 (use -v to see invocation)
>>>>>>>>>
tools/llvm-objdump/CMakeFiles/llvm-objdump.dir/build.make:173: recipe
>>>>>>>>> for target 'bin/llvm-objdump'
failed
>>>>>>>>> make[2]: *** [bin/llvm-objdump] Error 1
>>>>>>>>> make[2]: Target
'tools/llvm-objdump/CMakeFiles/llvm-objdump.dir/build'
>>>>>>>>> not remade because of errors.
>>>>>>>>> CMakeFiles/Makefile2:21861: recipe for
target
>>>>>>>>>
'tools/llvm-objdump/CMakeFiles/llvm-objdump.dir/all' failed
>>>>>>>>> make[1]: ***
[tools/llvm-objdump/CMakeFiles/llvm-objdump.dir/all] Error 2
>>>>>>>>>
_______________________________________________
>>>>>>>>> LLVM Developers mailing list
>>>>>>>>> llvm-dev at lists.llvm.org
>>>>>>>>>
http://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-dev
>>>>
>>

On Tue, May 24, 2016 at 3:03 PM, Jack Howarth
<howarth.mailing.lists at gmail.com> wrote:
> On Tue, May 24, 2016 at 2:37 PM, Jack Howarth
> <howarth.mailing.lists at gmail.com> wrote:
>> On Tue, May 24, 2016 at 2:28 PM, Chris Bieneman <beanz at
apple.com> wrote:
>>> Jack,
>>>
>>> What version of CMake are you using?
>>>
>>> -Chris
>>
>> Chris,
>>       I am using cmake 3.5.2. My read of this problem is as follows.
>> While libLLVM.dylib is being linked against -lxar when
>> -DLLVM_LINK_LLVM_DYLIB:BOOL=ON is passed to cmake, the libLLVM.dylib
>> is created with -Wl,-dead_strip such that any symbols from libxar not
>> explicitly used with in the object files of libLLVM.dylib are stripped
>> out. This means that those additional symbols used by llvm-objdump
>> aren't accessible from libLLVM.dylib's linkage on libxar and an
>> additional explicit linkage on libxar is required in the
>> tools/llvm-objdump/CMakeLists.txt when HAVE_LIBXAR and
>> LLVM_LINK_LLVM_DYLIB are set.
>>         Jack
>
> Also note that this issue doesn't arise for the cmake build with
> -DBUILD_SHARED_LIBS:BOOL=ON because the resulting
> lib/Object/CMakeFiles/LLVMObject.dir/link.txt contains...
>
> /sw/src/fink.build/llvm39-3.9.0-1/opt-bin/ccclang++  -fno-common -fPIC
> -fvisibility-inlines-hidden -Wall -W -Wno-unused-parameter
> -Wwrite-strings -Wcast-qual -Wmissing-field-initializers -pedantic
> -Wno-long-long -Wcovered-switch-default -Wnon-virtual-dtor
> -Wdelete-non-virtual-dtor -Werror=date-time -std=c++11 -O3 -dynamiclib
> -Wl,-headerpad_max_install_names  -Wl,-dead_strip  -L/sw/lib -o
> ../libLLVMObject.dylib -install_name @rpath/libLLVMObject.dylib
> CMakeFiles/LLVMObject.dir/Archive.cpp.o
> CMakeFiles/LLVMObject.dir/ArchiveWriter.cpp.o
> CMakeFiles/LLVMObject.dir/Binary.cpp.o
> CMakeFiles/LLVMObject.dir/COFFObjectFile.cpp.o
> CMakeFiles/LLVMObject.dir/ELF.cpp.o
> CMakeFiles/LLVMObject.dir/ELFObjectFile.cpp.o
> CMakeFiles/LLVMObject.dir/Error.cpp.o
> CMakeFiles/LLVMObject.dir/IRObjectFile.cpp.o
> CMakeFiles/LLVMObject.dir/MachOObjectFile.cpp.o
> CMakeFiles/LLVMObject.dir/MachOUniversal.cpp.o
> CMakeFiles/LLVMObject.dir/ModuleSummaryIndexObjectFile.cpp.o
> CMakeFiles/LLVMObject.dir/Object.cpp.o
> CMakeFiles/LLVMObject.dir/ObjectFile.cpp.o
> CMakeFiles/LLVMObject.dir/RecordStreamer.cpp.o
> CMakeFiles/LLVMObject.dir/SymbolicFile.cpp.o
> CMakeFiles/LLVMObject.dir/SymbolSize.cpp.o -lxar
> ../libLLVMBitReader.dylib ../libLLVMCore.dylib ../libLLVMMC.dylib
> ../libLLVMMCParser.dylib ../libLLVMSupport.dylib
> -Wl,-rpath, at executable_path/../lib
>
> and thus the linkage for  llvm-objdump is directly linked against
> libxar as in the default static lib build. Only the
> -DLLVM_LINK_LLVM_DYLIB:BOOL=ON build attempts to resolve the symbols
> from libxar using an indirect linkage on libxar in libLLVM.dylib.
>                Jack
>
Ignore that last comment. It does appear that
-DBUILD_SHARED_LIBS:BOOL=ON  produces the same error...

[ 98%] Linking CXX executable ../../bin/llvm-objdump
cd /sw/src/fink.build/llvm39-3.9.0-1/build/stage1/tools/llvm-objdump
&& /sw/bin/cmake -E cmake_link_script
CMakeFiles/llvm-objdump.dir/link.txt --verbose=1
/sw/src/fink.build/llvm39-3.9.0-1/opt-bin/ccclang++   -fno-common
-fPIC -fvisibility-inlines-hidden -Wall -W -Wno-unused-parameter
-Wwrite-strings -Wcast-qual -Wmissing-field-initializers -pedantic
-Wno-long-long -Wcovered-switch-default -Wnon-virtual-dtor
-Wdelete-non-virtual-dtor -Werror=date-time -std=c++11 -O3
-Wl,-search_paths_first -Wl,-headerpad_max_install_names  -L/sw/lib
-Wl,-dead_strip CMakeFiles/llvm-objdump.dir/llvm-objdump.cpp.o
CMakeFiles/llvm-objdump.dir/COFFDump.cpp.o
CMakeFiles/llvm-objdump.dir/ELFDump.cpp.o
CMakeFiles/llvm-objdump.dir/MachODump.cpp.o  -o ../../bin/llvm-objdump
 ../../lib/libLLVMX86AsmPrinter.dylib
../../lib/libLLVMPowerPCAsmPrinter.dylib
../../lib/libLLVMARMAsmPrinter.dylib ../../lib/libLLVMX86Desc.dylib
../../lib/libLLVMPowerPCDesc.dylib ../../lib/libLLVMARMDesc.dylib
../../lib/libLLVMX86Disassembler.dylib
../../lib/libLLVMPowerPCDisassembler.dylib
../../lib/libLLVMARMDisassembler.dylib ../../lib/libLLVMX86Info.dylib
../../lib/libLLVMPowerPCInfo.dylib ../../lib/libLLVMARMInfo.dylib
../../lib/libLLVMCodeGen.dylib ../../lib/libLLVMDebugInfoDWARF.dylib
../../lib/libLLVMMC.dylib ../../lib/libLLVMMCDisassembler.dylib
../../lib/libLLVMObject.dylib ../../lib/libLLVMSupport.dylib
-Wl,-rpath, at executable_path/../lib
Undefined symbols for architecture x86_64:
  "_xar_serialize", referenced from:
      DumpBitcodeSection(llvm::object::MachOObjectFile*, char const*,
unsigned int, bool, bool, bool, std::__1::basic_string<char,
std::__1::char_traits<char>, std::__1::allocator<char> >) in
MachODump.cpp.o
  "_xar_file_first", referenced from:
      DumpBitcodeSection(llvm::object::MachOObjectFile*, char const*,
unsigned int, bool, bool, bool, std::__1::basic_string<char,
std::__1::char_traits<char>, std::__1::allocator<char> >) in
MachODump.cpp.o
  "_xar_iter_new", referenced from:
      DumpBitcodeSection(llvm::object::MachOObjectFile*, char const*,
unsigned int, bool, bool, bool, std::__1::basic_string<char,
std::__1::char_traits<char>, std::__1::allocator<char> >) in
MachODump.cpp.o
  "_xar_prop_first", referenced from:
      DumpBitcodeSection(llvm::object::MachOObjectFile*, char const*,
unsigned int, bool, bool, bool, std::__1::basic_string<char,
std::__1::char_traits<char>, std::__1::allocator<char> >) in
MachODump.cpp.o
  "_xar_extract_tobuffersz", referenced from:
      DumpBitcodeSection(llvm::object::MachOObjectFile*, char const*,
unsigned int, bool, bool, bool, std::__1::basic_string<char,
std::__1::char_traits<char>, std::__1::allocator<char> >) in
MachODump.cpp.o
  "_xar_open", referenced from:
      DumpBitcodeSection(llvm::object::MachOObjectFile*, char const*,
unsigned int, bool, bool, bool, std::__1::basic_string<char,
std::__1::char_traits<char>, std::__1::allocator<char> >) in
MachODump.cpp.o
  "_xar_prop_get", referenced from:
      DumpBitcodeSection(llvm::object::MachOObjectFile*, char const*,
unsigned int, bool, bool, bool, std::__1::basic_string<char,
std::__1::char_traits<char>, std::__1::allocator<char> >) in
MachODump.cpp.o
  "_xar_close", referenced from:
      DumpBitcodeSection(llvm::object::MachOObjectFile*, char const*,
unsigned int, bool, bool, bool, std::__1::basic_string<char,
std::__1::char_traits<char>, std::__1::allocator<char> >) in
MachODump.cpp.o
  "_xar_prop_next", referenced from:
      DumpBitcodeSection(llvm::object::MachOObjectFile*, char const*,
unsigned int, bool, bool, bool, std::__1::basic_string<char,
std::__1::char_traits<char>, std::__1::allocator<char> >) in
MachODump.cpp.o
  "_xar_iter_free", referenced from:
      DumpBitcodeSection(llvm::object::MachOObjectFile*, char const*,
unsigned int, bool, bool, bool, std::__1::basic_string<char,
std::__1::char_traits<char>, std::__1::allocator<char> >) in
MachODump.cpp.o
  "_xar_file_next", referenced from:
      DumpBitcodeSection(llvm::object::MachOObjectFile*, char const*,
unsigned int, bool, bool, bool, std::__1::basic_string<char,
std::__1::char_traits<char>, std::__1::allocator<char> >) in
MachODump.cpp.o
ld: symbol(s) not found for architecture x86_64
clang: error: linker command failed with exit code 1 (use -v to see invocation)
tools/llvm-objdump/CMakeFiles/llvm-objdump.dir/build.make:190: recipe
for target 'bin/llvm-objdump' failed
make[2]: *** [bin/llvm-objdump] Error 1
make[2]: Leaving directory
'/sw/src/fink.build/llvm39-3.9.0-1/build/stage1'
CMakeFiles/Makefile2:22545: recipe for target
'tools/llvm-objdump/CMakeFiles/llvm-objdump.dir/all' failed
make[1]: *** [tools/llvm-objdump/CMakeFiles/llvm-objdump.dir/all] Error 2
make[1]: Leaving directory
'/sw/src/fink.build/llvm39-3.9.0-1/build/stage1'
Makefile:149: recipe for target 'all' failed
make: *** [all] Error 2

for the same reason. Appending -lxar to
tools/llvm-objdump/CMakeFiles/llvm-objdump.dir/link.txt likewise
eliminates the linkage error.
         Jack
>>>
>>>> On May 24, 2016, at 11:00 AM, Jack Howarth
<howarth.mailing.lists at gmail.com> wrote:
>>>>
>>>> On Tue, May 24, 2016 at 1:35 PM, Kevin Enderby <enderby at
apple.com> wrote:
>>>>> Hi Jack,
>>>>>
>>>>> Just a guess here, this may be the bug Chris helped me out
with in the use of the include file xar/xar.h which is not C++ safe.  I needed
to wrap my include via:
>>>>>
>>>>> #ifdef HAVE_LIBXAR
>>>>> extern "C" {
>>>>> #include <xar/xar.h>
>>>>> }
>>>>> #endif
>>>>>
>>>>> I think we may need some help from Chris to track this
down.  I’ll bug him in a bit to see if he can help us on this.
>>>>
>>>> While the build here with  -DLLVM_LINK_LLVM_DYLIB:BOOL=ON
passed on
>>>> the cmake options produces HAVE_LIBXAR:INTERNAL=1 in
CMakeCache.txt, I
>>>> don't see anything in the cmakefiles for tools/llvm-objdump
to provide
>>>> the necessary linkage on the system libxar shared library.
Appending
>>>> the missing linkage for -lxar onto
>>>>
build/stage1tools/llvm-objdump/CMakeFiles/llvm-objdump.dir/link.txt...
>>>>
>>>> /sw/src/fink.build/llvm39-3.9.0-1/opt-bin/ccclang++  
-fno-common
>>>> -fPIC -fvisibility-inlines-hidden -Wall -W
-Wno-unused-parameter
>>>> -Wwrite-strings -Wcast-qual -Wmissing-field-initializers
-pedantic
>>>> -Wno-long-long -Wcovered-switch-default -Wnon-virtual-dtor
>>>> -Wdelete-non-virtual-dtor -Werror=date-time -std=c++11 -O3
>>>> -Wl,-search_paths_first -Wl,-headerpad_max_install_names 
-L/sw/lib
>>>> -Wl,-dead_strip CMakeFiles/llvm-objdump.dir/llvm-objdump.cpp.o
>>>> CMakeFiles/llvm-objdump.dir/COFFDump.cpp.o
>>>> CMakeFiles/llvm-objdump.dir/ELFDump.cpp.o
>>>> CMakeFiles/llvm-objdump.dir/MachODump.cpp.o  -o
../../bin/llvm-objdump
>>>> ../../lib/libLLVM.dylib -Wl,-rpath, at executable_path/../lib
-lxar
>>>>
>>>> eliminates the bootstrap failure.
>>>>
>>>>>
>>>>> Kev
>>>>>
>>>>>> On May 24, 2016, at 10:28 AM, Jack Howarth
<howarth.mailing.lists at gmail.com> wrote:
>>>>>>
>>>>>> On Tue, May 24, 2016 at 1:24 PM, Jack Howarth
>>>>>> <howarth.mailing.lists at gmail.com> wrote:
>>>>>>> On Tue, May 24, 2016 at 1:22 PM, Jack Howarth
>>>>>>> <howarth.mailing.lists at gmail.com> wrote:
>>>>>>>> On Tue, May 24, 2016 at 12:08 PM, Reid Kleckner
<rnk at google.com> wrote:
>>>>>>>>> Kevin Enderby added those symbol uses in
r270491. It has a cmake
>>>>>>>>> feature test, and all the uses of those
symbols appear bracketed in
>>>>>>>>> HAVE_LIBXAR, so I don't know what went
wrong for you.
>>>>>>>>
>>>>>>>> The trigger for this build failure is the usage
of
>>>>>>>> -DLLVM_BUILD_EXTERNAL_COMPILER_RT:BOOL=ON. If I
drop that cmake
>>>>>>>> option, the linkage failure for llvm-objdump
disappears.
>>>>>>>
>>>>>>> Wrong cmake option. I meant to say that
-DLLVM_LINK_LLVM_DYLIB:BOOL=ON
>>>>>>> is the trigger of the build failure. Sorry for the
noise there.
>>>>>>
>>>>>> Filed as https://llvm.org/bugs/show_bug.cgi?id=27855
>>>>>>
>>>>>>>
>>>>>>>>
>>>>>>>>>
>>>>>>>>> On Tue, May 24, 2016 at 8:07 AM, Jack
Howarth via llvm-dev
>>>>>>>>> <llvm-dev at lists.llvm.org> wrote:
>>>>>>>>>> Is anyone else seeing a bootstrap
failure on x86_64-apple-darwin15 in
>>>>>>>>>> current trunk?
>>>>>>>>>>
>>>>>>>>>> [ 95%] Linking CXX executable
../../bin/llvm-objdump
>>>>>>>>>> Undefined symbols for architecture
x86_64:
>>>>>>>>>> "_xar_serialize", referenced
from:
>>>>>>>>>>    
DumpBitcodeSection(llvm::object::MachOObjectFile*, char const*,
>>>>>>>>>> unsigned int, bool, bool, bool,
std::__1::basic_string<char,
>>>>>>>>>> std::__1::char_traits<char>,
std::__1::allocator<char> >) in
>>>>>>>>>> MachODump.cpp.o
>>>>>>>>>> "_xar_file_first", referenced
from:
>>>>>>>>>>    
DumpBitcodeSection(llvm::object::MachOObjectFile*, char const*,
>>>>>>>>>> unsigned int, bool, bool, bool,
std::__1::basic_string<char,
>>>>>>>>>> std::__1::char_traits<char>,
std::__1::allocator<char> >) in
>>>>>>>>>> MachODump.cpp.o
>>>>>>>>>> "_xar_iter_new", referenced
from:
>>>>>>>>>>    
DumpBitcodeSection(llvm::object::MachOObjectFile*, char const*,
>>>>>>>>>> unsigned int, bool, bool, bool,
std::__1::basic_string<char,
>>>>>>>>>> std::__1::char_traits<char>,
std::__1::allocator<char> >) in
>>>>>>>>>> MachODump.cpp.o
>>>>>>>>>> "_xar_prop_first", referenced
from:
>>>>>>>>>>    
DumpBitcodeSection(llvm::object::MachOObjectFile*, char const*,
>>>>>>>>>> unsigned int, bool, bool, bool,
std::__1::basic_string<char,
>>>>>>>>>> std::__1::char_traits<char>,
std::__1::allocator<char> >) in
>>>>>>>>>> MachODump.cpp.o
>>>>>>>>>> "_xar_extract_tobuffersz",
referenced from:
>>>>>>>>>>    
DumpBitcodeSection(llvm::object::MachOObjectFile*, char const*,
>>>>>>>>>> unsigned int, bool, bool, bool,
std::__1::basic_string<char,
>>>>>>>>>> std::__1::char_traits<char>,
std::__1::allocator<char> >) in
>>>>>>>>>> MachODump.cpp.o
>>>>>>>>>> "_xar_open", referenced from:
>>>>>>>>>>    
DumpBitcodeSection(llvm::object::MachOObjectFile*, char const*,
>>>>>>>>>> unsigned int, bool, bool, bool,
std::__1::basic_string<char,
>>>>>>>>>> std::__1::char_traits<char>,
std::__1::allocator<char> >) in
>>>>>>>>>> MachODump.cpp.o
>>>>>>>>>> "_xar_prop_get", referenced
from:
>>>>>>>>>>    
DumpBitcodeSection(llvm::object::MachOObjectFile*, char const*,
>>>>>>>>>> unsigned int, bool, bool, bool,
std::__1::basic_string<char,
>>>>>>>>>> std::__1::char_traits<char>,
std::__1::allocator<char> >) in
>>>>>>>>>> MachODump.cpp.o
>>>>>>>>>> "_xar_close", referenced
from:
>>>>>>>>>>    
DumpBitcodeSection(llvm::object::MachOObjectFile*, char const*,
>>>>>>>>>> unsigned int, bool, bool, bool,
std::__1::basic_string<char,
>>>>>>>>>> std::__1::char_traits<char>,
std::__1::allocator<char> >) in
>>>>>>>>>> MachODump.cpp.o
>>>>>>>>>> "_xar_prop_next", referenced
from:
>>>>>>>>>>    
DumpBitcodeSection(llvm::object::MachOObjectFile*, char const*,
>>>>>>>>>> unsigned int, bool, bool, bool,
std::__1::basic_string<char,
>>>>>>>>>> std::__1::char_traits<char>,
std::__1::allocator<char> >) in
>>>>>>>>>> MachODump.cpp.o
>>>>>>>>>> "_xar_iter_free", referenced
from:
>>>>>>>>>>    
DumpBitcodeSection(llvm::object::MachOObjectFile*, char const*,
>>>>>>>>>> unsigned int, bool, bool, bool,
std::__1::basic_string<char,
>>>>>>>>>> std::__1::char_traits<char>,
std::__1::allocator<char> >) in
>>>>>>>>>> MachODump.cpp.o
>>>>>>>>>> "_xar_file_next", referenced
from:
>>>>>>>>>>    
DumpBitcodeSection(llvm::object::MachOObjectFile*, char const*,
>>>>>>>>>> unsigned int, bool, bool, bool,
std::__1::basic_string<char,
>>>>>>>>>> std::__1::char_traits<char>,
std::__1::allocator<char> >) in
>>>>>>>>>> MachODump.cpp.o
>>>>>>>>>> ld: symbol(s) not found for
architecture x86_64
>>>>>>>>>> clang: error: linker command failed
with exit code 1 (use -v to see invocation)
>>>>>>>>>>
tools/llvm-objdump/CMakeFiles/llvm-objdump.dir/build.make:173: recipe
>>>>>>>>>> for target 'bin/llvm-objdump'
failed
>>>>>>>>>> make[2]: *** [bin/llvm-objdump] Error 1
>>>>>>>>>> make[2]: Target
'tools/llvm-objdump/CMakeFiles/llvm-objdump.dir/build'
>>>>>>>>>> not remade because of errors.
>>>>>>>>>> CMakeFiles/Makefile2:21861: recipe for
target
>>>>>>>>>>
'tools/llvm-objdump/CMakeFiles/llvm-objdump.dir/all' failed
>>>>>>>>>> make[1]: ***
[tools/llvm-objdump/CMakeFiles/llvm-objdump.dir/all] Error 2
>>>>>>>>>>
_______________________________________________
>>>>>>>>>> LLVM Developers mailing list
>>>>>>>>>> llvm-dev at lists.llvm.org
>>>>>>>>>>
http://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-dev
>>>>>
>>>