LLVM：“导出”班级
我想使用 LLVM 从我的程序中调用此代码：
#include <string>
#include <iostream>
extern "C" void hello() {
std::cout << "hello" << std::endl;
}
class Hello {
public:
Hello() {
std::cout <<"Hello::Hello()" << std::endl;
};
int hello() {
std::cout<< "Hello::hello()" << std::endl;
return 99;
};
};
我使用 clang++ -emit-llvm -c -o hello.bc hello.cpp 将此代码编译为 llvm 字节代码，然后我想从此程序中调用它：（
#include <llvm/ExecutionEngine/ExecutionEngine.h>
#include <llvm/ExecutionEngine/GenericValue.h>
#include <llvm/ExecutionEngine/JIT.h>
#include <llvm/LLVMContext.h>
#include <llvm/Module.h>
#include <llvm/Target/TargetSelect.h>
#include <llvm/Support/MemoryBuffer.h>
#include <llvm/Support/IRReader.h>
#include <string>
#include <iostream>
#include <vector>
using namespace std;
using namespace llvm;
void callFunction(string file, string function) {
InitializeNativeTarget();
LLVMContext context;
string error;
MemoryBuffer* buff = MemoryBuffer::getFile(file);
assert(buff);
Module* m = getLazyBitcodeModule(buff, context, &error);
ExecutionEngine* engine = ExecutionEngine::create(m);
Function* func = m->getFunction(function);
vector<GenericValue> args(0);
engine->runFunction(func, args);
func = m->getFunction("Hello::Hello");
engine->runFunction(func, args);
}
int main() {
callFunction("hello.bc", "hello");
}
使用 g++ -g main.cpp 'llvm-config --cppflags --ldflags --libs core jit native bitreader' 编译）
我可以调用 hello( ) 功能没有任何问题。 我的问题是：如何使用 LLVM 创建 Hello 类的新实例？ 当我调用 Hello::Hello() 时遇到分段错误
感谢您的任何提示！
曼努埃尔
I'd like to call this code from my program using LLVM:
#include <string>
#include <iostream>
extern "C" void hello() {
std::cout << "hello" << std::endl;
}
class Hello {
public:
Hello() {
std::cout <<"Hello::Hello()" << std::endl;
};
int hello() {
std::cout<< "Hello::hello()" << std::endl;
return 99;
};
};
I compiled this code to llvm byte code using clang++ -emit-llvm -c -o hello.bc hello.cpp and then I want to call it from this program:
#include <llvm/ExecutionEngine/ExecutionEngine.h>
#include <llvm/ExecutionEngine/GenericValue.h>
#include <llvm/ExecutionEngine/JIT.h>
#include <llvm/LLVMContext.h>
#include <llvm/Module.h>
#include <llvm/Target/TargetSelect.h>
#include <llvm/Support/MemoryBuffer.h>
#include <llvm/Support/IRReader.h>
#include <string>
#include <iostream>
#include <vector>
using namespace std;
using namespace llvm;
void callFunction(string file, string function) {
InitializeNativeTarget();
LLVMContext context;
string error;
MemoryBuffer* buff = MemoryBuffer::getFile(file);
assert(buff);
Module* m = getLazyBitcodeModule(buff, context, &error);
ExecutionEngine* engine = ExecutionEngine::create(m);
Function* func = m->getFunction(function);
vector<GenericValue> args(0);
engine->runFunction(func, args);
func = m->getFunction("Hello::Hello");
engine->runFunction(func, args);
}
int main() {
callFunction("hello.bc", "hello");
}
(compiled using g++ -g main.cpp 'llvm-config --cppflags --ldflags --libs core jit native bitreader')
I can call the hello() function without any problems.
My question is: how can I create a new instance of the Hello class using LLVM?
I'm getting a segmentation fault when I call Hello::Hello()
Thanks for any hints!!
Manuel
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在给定源上运行
clang++ -emit-llvm不会发出 Hello::Hello，并且m->getFunction("Hello::Hello")也不会即使它被发射了也能找到它。我猜它崩溃是因为func为空。通常不建议尝试直接从 LLVM JIT 调用不是
extern "C"的函数...我建议编写如下所示的包装器，并使用 clang 编译它（或使用clang API，取决于你在做什么）：Running
clang++ -emit-llvmon the given source won't emit Hello::Hello, andm->getFunction("Hello::Hello")wouldn't find it even if it were emitted. I would guess it's crashing becausefuncis null.Trying to directly call functions which aren't
extern "C"from the LLVM JIT is generally not recommended... I'd suggest writing a wrapper like the following, and compiling it with clang (or using the clang API, depending on what you're doing):