Linking against clang-llvm

问题:

I've been working on a small tool with clang/llvm but I haven't been able to successfully get g++ and gnu's linker to properly link my code against clang.

my linker is generating the following errors:

undefined reference to `clang::FileManager::~FileManager()'

undefined reference to `clang::FileManager::FileManager()'

undefined reference to `llvm::sys::getHostTriple()'

undefined reference to `clang::Diagnostic::Diagnostic(clang::DiagnosticClient*)'

undefined reference to `llvm::outs()'

undefined reference to `clang::TargetInfo::CreateTargetInfo(clang::Diagnostic&, clang::TargetOptions&)'

undefined reference to `clang::SourceManager::getOrCreateContentCache(clang::FileEntry const*)'

undefined reference to `clang::SourceManager::createFileID(clang::SrcMgr::ContentCache const*, clang::SourceLocation, clang::SrcMgr::CharacteristicKind, unsigned int, unsigned int)'

my compile commands looks like this:

g++ -g -fno-rtti -I~/llvm-2.8/tools/clang-2.8/include \
  -I~/llvm-2.8/llvm/include \
  `~/bin/llvm-config --cxxflags` \
  -c Frontend.cpp

g++ -g -fno-rtti -I~/llvm-2.8/tools/clang-2.8/include \
  -I~/llvm-2.8/llvm/include \
  `~/bin/llvm-config --cxxflags` \
  -c exec.cpp

g++ -I~/llvm-2.8/tools/clang-2.8/include \
    -I~/llvm-2.8/llvm/include -L~/opt/lib/ \
    -g -fno-rtti -lclangDriver -lclangAnalysis \
    -lclangFrontend -lclangSema -lclangAST -lclangParse \
    -lclangLex -lclangBasic  \
    `~/bin/llvm-config --cxxflags --ldflags --libs`  \
    Frontend.o exec.o -o run

any tips or advice would be welcomed.

cheers, ct

PS: I've been exploring some of the information on this page:

http://ubuntuforums.org/showthread.php?t=532693

and it might do the trick, will post a comment on that tip when I can.

Solution

using clang code from this tutorial (which had to be modified to remove the references to FileSystemOptions b/c clang/Basic/FileSystemOptions.h doesn't exist in clang-2.8): http://clangtutorial.codeplex.com/

g++ tutorial1.cpp -g -fno-rtti -lclangFrontend -lclangDriver       \
    -lclangCodeGen -lclangSema -lclangChecker -lclangAnalysis      \
    -lclangRewrite -lclangAST -lclangParse -lclangLex -lclangBasic \
    -lLLVMSupport -lLLVMSystem -I~/opt/include/                    \
    `llvm-config --cxxflags --ldflags --libs all`

seemed to do the trick!

回答1:

When I've built some stuff against llvm / clang, this is what I've used to build it. Perhaps you can compare the two build lines.

Also, the llvm-config command I've used has been: llvm-config --cxxflags --ldflags --libs backend.

Finally, this is likely partially related to an ordering issue. You probably want to include the libraries for llvm before you include the clang libraries.

/usr/bin/g++                                                              \
    -fno-exceptions -fno-rtti -fno-common                                 \
    -I/Users/wlynch/Homebrew/include                                      \
    -DNDEBUG -D_GNU_SOURCE -D__STDC_LIMIT_MACROS -D__STDC_CONSTANT_MACROS \
    ../src/main.cpp -c -o src/main.cpp.0.o

/usr/bin/g++
     src/main.cpp.0.o -o /Users/wlynch/Dropbox/Clang/Indexer/build/main               \
     -L/Users/wlynch/Homebrew/lib -L/Users/wlynch/Homebrew/lib                        \
     -lpthread -lm                                                                    \
     -lLLVMX86Disassembler -lLLVMX86AsmParser -lLLVMX86CodeGen -lLLVMSelectionDAG     \
     -lLLVMAsmPrinter -lLLVMMCParser -lLLVMCodeGen -lLLVMScalarOpts -lLLVMInstCombine \
     -lLLVMTransformUtils -lLLVMipa -lLLVMAnalysis -lLLVMTarget -lLLVMCore            \
     -lLLVMX86AsmPrinter -lLLVMMC -lLLVMX86Info -lLLVMSupport -lLLVMSystem            \
     -lclangAST -lclangAnalysis -lclangBasic -lclangChecker -lclangCodeGen            \
     -lclangDriver -lclangFrontend -lclangFrontendTool -lclangIndex -lclangLex        \
     -lclangParse -lclangRewrite -lclangSema -lclangSerialization

回答2:

I assume you have back quotes around ~/bin/llvm-config, right?

That being said, move the -l options and the

`~/bin/llvm-config --cxxflags --ldflags --libs`

after the .o files on the command line. Stuff won't be taken out of the libraries unless referenced by a preceding object file.