我正在处理LLVM Tutorial，但是编译时遇到问题。我写了一个最小的示例来重现该问题:
#include "llvm/Module.h"
#include "llvm/LLVMContext.h"
int main(int argc, char **argv) {
llvm::Module *module = new llvm::Module("test", llvm::getGlobalContext());
return 0;
}
当我尝试编译时，我得到了一堆“ undefined reference ”错误:
clang++ `llvm-config --cxxflags` -c -o test.o test.cpp
clang++ test.o `llvm-config --ldflags --libs core` -o test
/usr/lib/llvm-2.9/lib/libLLVMSupport.a(Signals.o): In function `PrintStackTrace(void*)':
(.text+0x6c): undefined reference to `dladdr'
/usr/lib/llvm-2.9/lib/libLLVMSupport.a(Signals.o): In function `PrintStackTrace(void*)':
(.text+0x1f6): undefined reference to `dladdr'
/usr/lib/llvm-2.9/lib/libLLVMSupport.a(Mutex.o): In function `llvm::sys::MutexImpl::MutexImpl(bool)':
(.text+0x53): undefined reference to `pthread_mutexattr_init'
/usr/lib/llvm-2.9/lib/libLLVMSupport.a(Mutex.o): In function `llvm::sys::MutexImpl::MutexImpl(bool)':
(.text+0x64): undefined reference to `pthread_mutexattr_settype'
/usr/lib/llvm-2.9/lib/libLLVMSupport.a(Mutex.o): In function `llvm::sys::MutexImpl::MutexImpl(bool)':
(.text+0x74): undefined reference to `pthread_mutexattr_setpshared'
/usr/lib/llvm-2.9/lib/libLLVMSupport.a(Mutex.o): In function `llvm::sys::MutexImpl::MutexImpl(bool)':
(.text+0x88): undefined reference to `pthread_mutexattr_destroy'
/usr/lib/llvm-2.9/lib/libLLVMSupport.a(Mutex.o): In function `llvm::sys::MutexImpl::tryacquire()':
(.text+0x179): undefined reference to `pthread_mutex_trylock'
/usr/lib/llvm-2.9/lib/libLLVMSupport.a(RWMutex.o): In function `llvm::sys::RWMutexImpl::RWMutexImpl()':
(.text+0x3e): undefined reference to `pthread_rwlock_init'
/usr/lib/llvm-2.9/lib/libLLVMSupport.a(RWMutex.o): In function `llvm::sys::RWMutexImpl::~RWMutexImpl()':
(.text+0x80): undefined reference to `pthread_rwlock_destroy'
/usr/lib/llvm-2.9/lib/libLLVMSupport.a(RWMutex.o): In function `llvm::sys::RWMutexImpl::reader_acquire()':
(.text+0xb9): undefined reference to `pthread_rwlock_rdlock'
/usr/lib/llvm-2.9/lib/libLLVMSupport.a(RWMutex.o): In function `llvm::sys::RWMutexImpl::reader_release()':
(.text+0xe9): undefined reference to `pthread_rwlock_unlock'
/usr/lib/llvm-2.9/lib/libLLVMSupport.a(RWMutex.o): In function `llvm::sys::RWMutexImpl::writer_acquire()':
(.text+0x119): undefined reference to `pthread_rwlock_wrlock'
/usr/lib/llvm-2.9/lib/libLLVMSupport.a(RWMutex.o): In function `llvm::sys::RWMutexImpl::writer_release()':
(.text+0x149): undefined reference to `pthread_rwlock_unlock'
/usr/lib/llvm-2.9/lib/libLLVMSupport.a(Threading.o): In function `llvm::llvm_execute_on_thread(void (*)(void*), void*, unsigned int)':
(.text+0x1cc): undefined reference to `pthread_create'
/usr/lib/llvm-2.9/lib/libLLVMSupport.a(Threading.o): In function `llvm::llvm_execute_on_thread(void (*)(void*), void*, unsigned int)':
(.text+0x208): undefined reference to `pthread_attr_setstacksize'
/usr/lib/llvm-2.9/lib/libLLVMSupport.a(Threading.o): In function `llvm::llvm_execute_on_thread(void (*)(void*), void*, unsigned int)':
(.text+0x228): undefined reference to `pthread_join'
clang: error: linker command failed with exit code 1 (use -v to see invocation)
make: *** [test] Error 1
如果查看dladdr的联机帮助页，它说我需要与
-ldl链接。但是我已经使用llvm-config做到了:$ llvm-config --ldflags --libs core
-L/usr/lib/llvm-2.9/lib -lpthread -lffi -ldl -lm
-lLLVMCore -lLLVMSupport -L/usr/lib/llvm-2.9/lib
此外，
-ldl会以正确的顺序显示(即，在需要符号的.o文件之后)。我对于调试此问题的下一步不知所措。谁能指出我正确的方向？我在Ubuntu 12.04上运行LVVM 2.9-7。
最佳答案
要求符号的库包含在-lLLVMSupport中，因此-ldl必须在-lLLVMSupport之后。我改变了这个:
`llvm-config --ldflags --libs core`
对此:
`llvm-config --libs core` `llvm-config --ldflags`
链接器成功。