llvm dev - Feb 2016 - undefined reference to typeinfo for CmpInst

Hi all,

I am having some some trouble with LLVM 3.8... I built it with GCC 4.8.2 
with cmake and no special CXX/C flags. That means in case of GCC that 
RTTI is switched on, I believe.

However, building my MCJIT application against the just built LLVM and 
linking results in:

libqdp.a(qdp_llvm.o):(.rodata._ZTIN4llvm8FCmpInstE[_ZTIN4llvm8FCmpInstE]+0x10): 
undefined reference to `typeinfo for llvm::CmpInst'
libqdp.a(qdp_jit_util.o):(.rodata._ZTIN4llvm16ExtractValueInstE[_ZTIN4llvm16ExtractValueInstE]+0x10):
undefined reference to `typeinfo for llvm::UnaryInstruction'
libqdp.a(qdp_jit_util.o):(.rodata._ZTIN4llvm15InsertValueInstE[_ZTIN4llvm15InsertValueInstE]+0x10):
undefined reference to `typeinfo for llvm::Instruction'
collect2: error: ld returned 1 exit status


I searched for this and there seem to be two common causes for this

1) There are virtual functions declared but never defined (I don't think 
that's the case, since LLVM has nightly tests)

2) Something's wrong with the RTTI settings.

I greped the LLVM source and it seems typeinfo is never used, so I 
though it's a good idea to build LLVM with RTTI switched off:

However, building LLVM with RTTI switched off (see build script below) 
results during the build in

/usr/bin/ld: ../../lib/libLLVMX86CodeGen.a(X86AsmPrinter.cpp.o): 
relocation R_X86_64_32S against `.rodata' can not be used when making a 
shared object; recompile with -fPIC
../../lib/libLLVMX86CodeGen.a: could not read symbols: Bad value
collect2: error: ld returned 1 exit status

I am not sure how to proceed from here..



Thanks,
Frank



SRC=$HOME/svn/llvm-3.8

CMAKE_BUILD_TYPE="Debug"
CMAKE_INSTALL_PREFIX="$HOME/toolchain/install/llvm-3.8"
LLVM_TARGETS_TO_BUILD="X86"

CXX="/dist/gcc-4.8.2/bin/g++"
CC="/dist/gcc-4.8.2/bin/gcc"

#-DBUILD_SHARED_LIBS="ON" \


cmake -G "Unix Makefiles" \
-DCMAKE_CXX_FLAGS="-fno-rtti" \
-DCMAKE_C_FLAGS="-fno-rtti" \
-DCMAKE_CXX_COMPILER=$CXX \
-DCMAKE_C_COMPILER=$CC \
-DCMAKE_BUILD_TYPE=$CMAKE_BUILD_TYPE \
-DCMAKE_INSTALL_PREFIX=$CMAKE_INSTALL_PREFIX \
-DLLVM_TARGETS_TO_BUILD=$LLVM_TARGETS_TO_BUILD \
$SRC

Solved. Recompiling LLVM with "-fno-rtti -fPIC" and building my 
application with "-fno-rtti" solved the issue.

As a result of this experiment I conclude that the LLVM library cannot 
be used in applications that make use of RTTI. I guess that's a bug.

Frank


On 02/19/2016 01:46 PM, Frank Winter via llvm-dev wrote:
> Hi all,
>
> I am having some some trouble with LLVM 3.8... I built it with GCC 4.8.2
> with cmake and no special CXX/C flags. That means in case of GCC that
> RTTI is switched on, I believe.
>
> However, building my MCJIT application against the just built LLVM and
> linking results in:
>
>
libqdp.a(qdp_llvm.o):(.rodata._ZTIN4llvm8FCmpInstE[_ZTIN4llvm8FCmpInstE]+0x10):
> undefined reference to `typeinfo for llvm::CmpInst'
>
libqdp.a(qdp_jit_util.o):(.rodata._ZTIN4llvm16ExtractValueInstE[_ZTIN4llvm16ExtractValueInstE]+0x10):
> undefined reference to `typeinfo for llvm::UnaryInstruction'
>
libqdp.a(qdp_jit_util.o):(.rodata._ZTIN4llvm15InsertValueInstE[_ZTIN4llvm15InsertValueInstE]+0x10):
> undefined reference to `typeinfo for llvm::Instruction'
> collect2: error: ld returned 1 exit status
>
>
> I searched for this and there seem to be two common causes for this
>
> 1) There are virtual functions declared but never defined (I don't
think
> that's the case, since LLVM has nightly tests)
>
> 2) Something's wrong with the RTTI settings.
>
> I greped the LLVM source and it seems typeinfo is never used, so I
> though it's a good idea to build LLVM with RTTI switched off:
>
> However, building LLVM with RTTI switched off (see build script below)
> results during the build in
>
> /usr/bin/ld: ../../lib/libLLVMX86CodeGen.a(X86AsmPrinter.cpp.o):
> relocation R_X86_64_32S against `.rodata' can not be used when making a
> shared object; recompile with -fPIC
> ../../lib/libLLVMX86CodeGen.a: could not read symbols: Bad value
> collect2: error: ld returned 1 exit status
>
> I am not sure how to proceed from here..
>
>
>
> Thanks,
> Frank
>
>
>
> SRC=$HOME/svn/llvm-3.8
>
> CMAKE_BUILD_TYPE="Debug"
> CMAKE_INSTALL_PREFIX="$HOME/toolchain/install/llvm-3.8"
> LLVM_TARGETS_TO_BUILD="X86"
>
> CXX="/dist/gcc-4.8.2/bin/g++"
> CC="/dist/gcc-4.8.2/bin/gcc"
>
> #-DBUILD_SHARED_LIBS="ON" \
>
>
> cmake -G "Unix Makefiles" \
> -DCMAKE_CXX_FLAGS="-fno-rtti" \
> -DCMAKE_C_FLAGS="-fno-rtti" \
> -DCMAKE_CXX_COMPILER=$CXX \
> -DCMAKE_C_COMPILER=$CC \
> -DCMAKE_BUILD_TYPE=$CMAKE_BUILD_TYPE \
> -DCMAKE_INSTALL_PREFIX=$CMAKE_INSTALL_PREFIX \
> -DLLVM_TARGETS_TO_BUILD=$LLVM_TARGETS_TO_BUILD \
> $SRC
>
> _______________________________________________
> LLVM Developers mailing list
> llvm-dev at lists.llvm.org
> http://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-dev

On Fri, Feb 19, 2016 at 11:09 AM, Frank Winter via llvm-dev <
llvm-dev at lists.llvm.org> wrote:
> Solved. Recompiling LLVM with "-fno-rtti -fPIC" and building my
> application with "-fno-rtti" solved the issue.
>
LLVM should already set -fno-rtti by default. I think re-compiling your app
with -fno-rtti is what fixed the undefined typeinfo symbol errors.

It looks like you are linking LLVM static libs into a shared library, so
you also needed to build LLVM with -fPIC. The documented way of doing this
is to pass -DLLVM_ENABLE_PIC=ON to cmake.

> As a result of this experiment I conclude that the LLVM library cannot be
> used in applications that make use of RTTI. I guess that's a bug.

You can enable RTTI by passing -DLLVM_ENABLE_RTTI=ON to cmake. This is
documented here:
http://llvm.org/docs/CMake.html#llvm-specific-variables

It sounds like the real bug is "make the build documentation less
confusing". Sorry about that. =/
-------------- next part --------------
An HTML attachment was scrubbed...
URL:
<http://lists.llvm.org/pipermail/llvm-dev/attachments/20160219/ce5380aa/attachment.html>

Hi Frank,

I am building LLVM 3.7.1 with RTTI and it works fine. I am using the 
following flags:

         cmake \
             -DCMAKE_BUILD_TYPE=Release \
             -DCMAKE_INSTALL_PREFIX=$(LLVM_DST) \
             -DLLVM_BUILD_TOOLS=OFF \
             -DLLVM_ENABLE_ASSERTIONS=ON \
             -DLLVM_ENABLE_RTTI=ON \
             -DLLVM_ENABLE_WERROR=ON \
             -DLLVM_REQUIRES_RTTI=ON \
             -DLLVM_TARGETS_TO_BUILD="X86" \
             -DLLVM_TARGET_ARCH="X86" \
             $(LLVM_SVN)

You apparently need to both use  LLVM_ENABLE_RTTI=ON and 
LLVM_REQUIRES_RTTI=ON.

Cheers
Morten

On 20/02/16 06:09, Frank Winter via llvm-dev wrote:
> Solved. Recompiling LLVM with "-fno-rtti -fPIC" and building my 
> application with "-fno-rtti" solved the issue.
>
> As a result of this experiment I conclude that the LLVM library cannot 
> be used in applications that make use of RTTI. I guess that's a bug.
>
> Frank
>
>
> On 02/19/2016 01:46 PM, Frank Winter via llvm-dev wrote:
>> Hi all,
>>
>> I am having some some trouble with LLVM 3.8... I built it with GCC
4.8.2
>> with cmake and no special CXX/C flags. That means in case of GCC that
>> RTTI is switched on, I believe.
>>
>> However, building my MCJIT application against the just built LLVM and
>> linking results in:
>>
>>
libqdp.a(qdp_llvm.o):(.rodata._ZTIN4llvm8FCmpInstE[_ZTIN4llvm8FCmpInstE]+0x10):
>>
>> undefined reference to `typeinfo for llvm::CmpInst'
>>
libqdp.a(qdp_jit_util.o):(.rodata._ZTIN4llvm16ExtractValueInstE[_ZTIN4llvm16ExtractValueInstE]+0x10):
>>
>> undefined reference to `typeinfo for llvm::UnaryInstruction'
>>
libqdp.a(qdp_jit_util.o):(.rodata._ZTIN4llvm15InsertValueInstE[_ZTIN4llvm15InsertValueInstE]+0x10):
>>
>> undefined reference to `typeinfo for llvm::Instruction'
>> collect2: error: ld returned 1 exit status
>>
>>
>> I searched for this and there seem to be two common causes for this
>>
>> 1) There are virtual functions declared but never defined (I don't
think
>> that's the case, since LLVM has nightly tests)
>>
>> 2) Something's wrong with the RTTI settings.
>>
>> I greped the LLVM source and it seems typeinfo is never used, so I
>> though it's a good idea to build LLVM with RTTI switched off:
>>
>> However, building LLVM with RTTI switched off (see build script below)
>> results during the build in
>>
>> /usr/bin/ld: ../../lib/libLLVMX86CodeGen.a(X86AsmPrinter.cpp.o):
>> relocation R_X86_64_32S against `.rodata' can not be used when
making a
>> shared object; recompile with -fPIC
>> ../../lib/libLLVMX86CodeGen.a: could not read symbols: Bad value
>> collect2: error: ld returned 1 exit status
>>
>> I am not sure how to proceed from here..
>>
>>
>>
>> Thanks,
>> Frank
>>
>>
>>
>> SRC=$HOME/svn/llvm-3.8
>>
>> CMAKE_BUILD_TYPE="Debug"
>> CMAKE_INSTALL_PREFIX="$HOME/toolchain/install/llvm-3.8"
>> LLVM_TARGETS_TO_BUILD="X86"
>>
>> CXX="/dist/gcc-4.8.2/bin/g++"
>> CC="/dist/gcc-4.8.2/bin/gcc"
>>
>> #-DBUILD_SHARED_LIBS="ON" \
>>
>>
>> cmake -G "Unix Makefiles" \
>> -DCMAKE_CXX_FLAGS="-fno-rtti" \
>> -DCMAKE_C_FLAGS="-fno-rtti" \
>> -DCMAKE_CXX_COMPILER=$CXX \
>> -DCMAKE_C_COMPILER=$CC \
>> -DCMAKE_BUILD_TYPE=$CMAKE_BUILD_TYPE \
>> -DCMAKE_INSTALL_PREFIX=$CMAKE_INSTALL_PREFIX \
>> -DLLVM_TARGETS_TO_BUILD=$LLVM_TARGETS_TO_BUILD \
>> $SRC
>>
>> _______________________________________________
>> LLVM Developers mailing list
>> llvm-dev at lists.llvm.org
>> http://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-dev
>
> _______________________________________________
> LLVM Developers mailing list
> llvm-dev at lists.llvm.org
> http://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-dev