[llvm-dev] undefined reference to typeinfo for CmpInst

[Morten Brodersen via llvm-dev]

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
>>
>> _______________________________________________
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>
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