I configured with options: --enable-debug-runtime --prefix=/usr/local/llvm/2.7 --enable-optimized --enable-assertions --enable-shared Build fails with the errors: llvm[2]: Linking Release executable opt (without symbols) /tmp/llvm-build/2.7/llvm-objects/tools/opt/Release/AnalysisWrappers.o(.text+0xb0): In function `(anonymous namespace)::ExternalFunctionsPassedConstants::~ExternalFunctionsPassedConstants()': : undefined reference to `llvm::ModulePass::~ModulePass()' /tmp/llvm-build/2.7/llvm-objects/tools/opt/Release/AnalysisWrappers.o(.text+0xdc): In function `(anonymous namespace)::CallGraphPrinter::~CallGraphPrinter()': : undefined reference to `llvm::ModulePass::~ModulePass()' <...skipped...> /tmp/llvm-build/2.7/llvm-objects/tools/opt/Release/AnalysisWrappers.o(.text+0x63d): In function `(anonymous namespace)::CallGraphPrinter::getAnalysisUsage(llvm::AnalysisUsage&) const': : undefined reference to `llvm::SmallVectorBase::grow_pod(unsigned int, unsigned int)' I used gcc-4.3.1 is used to compile. With gcc-4.5.0 build also fails. FreeBSD-8.0 Yuri