I followed the libTooling tutorial at here: to write the loop-convert program. When I built it, I got the following error (I used the unofficial monorepo to build clang):
$ ninja loop-convert
[1/1] Linking CXX executable bin/loop-convert
FAILED: : && /usr/bin/clang++-6.0 -fPIC -fvisibility-inlines-hidden -Werror=date-time -Werror=unguarded-availability-new -std=c++11 -Wall -Wextra -Wno-unused-parameter -Wwrite-strings -Wcast-qual -Wmissing-field-initializers -pedantic -Wno-long-long -Wcovered-switch-default -Wno-noexcept-type -Wnon-virtual-dtor -Wdelete-non-virtual-dtor -Wstring-conversion -fdiagnostics-color -fno-common -Woverloaded-virtual -Wno-nested-anon-types -g -fuse-ld=lld-6.0 -Wl,--color-diagnostics -Wl,-allow-shlib-undefined tools/clang/tools/extra/loop-convert/CMakeFiles/loop-convert.dir/LoopConvert.cpp.o -o bin/loop-convert lib/libLLVMSupport.so.8svn -lpthread lib/libclangTooling.so.8svn lib/libclangBasic.so.8svn lib/libclangASTMatchers.so.8svn -Wl,-rpath,"\$ORIGIN/../lib" && :
/usr/bin/ld.lld-6.0: error: undefined symbol: clang::PCHContainerOperations::PCHContainerOperations()
>>> referenced by new_allocator.h:120 (/usr/bin/../lib/gcc/x86_64-linux-gnu/5.4.0/../../../../include/c++/5.4.0/ext/new_allocator.h:120)
>>> tools/clang/tools/extra/loop-convert/CMakeFiles/loop-convert.dir/LoopConvert.cpp.o:(void __gnu_cxx::new_allocator<clang::PCHContainerOperations>::construct<clang::PCHContainerOperations>(clang::PCHContainerOperations*))
/usr/bin/ld.lld-6.0: error: undefined symbol: vtable for clang::SyntaxOnlyAction
>>> referenced by FrontendActions.h:158 (/home/lu/work/git-repos/llvm-mono/llvm-project/clang/include/clang/Frontend/FrontendActions.h:158)
>>> tools/clang/tools/extra/loop-convert/CMakeFiles/loop-convert.dir/LoopConvert.cpp.o:(clang::SyntaxOnlyAction::SyntaxOnlyAction())
/usr/bin/ld.lld-6.0: error: undefined symbol: clang::FrontendAction::FrontendAction()
>>> referenced by FrontendAction.h:253 (/home/lu/work/git-repos/llvm-mono/llvm-project/clang/include/clang/Frontend/FrontendAction.h:253)
>>> tools/clang/tools/extra/loop-convert/CMakeFiles/loop-convert.dir/LoopConvert.cpp.o:(clang::ASTFrontendAction::ASTFrontendAction())
/usr/bin/ld.lld-6.0: error: undefined symbol: vtable for clang::ASTFrontendAction
>>> referenced by FrontendAction.h:253 (/home/lu/work/git-repos/llvm-mono/llvm-project/clang/include/clang/Frontend/FrontendAction.h:253)
>>> tools/clang/tools/extra/loop-convert/CMakeFiles/loop-convert.dir/LoopConvert.cpp.o:(clang::ASTFrontendAction::ASTFrontendAction())
clang: error: linker command failed with exit code 1 (use -v to see invocation)
ninja: build stopped: subcommand failed.
Can anyone point me to the right direction to fix it?
Thanks.