llvm JIT向模块添加库 [英] llvm JIT add library to module

问题描述

我正在研究使用LLVM的JIT.该语言有一个用C ++编写的小运行时，我使用clang编译为LLVM IR

I am working on a JIT that uses LLVM. The language has a small run-time written in C++ which I compile down to LLVM IR using clang

clang++ runtime.cu --cuda-gpu-arch=sm_50 -c -emit-llvm

，然后加载* .bc文件，生成其他IR，然后即时执行.之所以使用CUDA，是因为我想在运行时添加一些GPU加速.但是，这引入了特定于CUDA的外部函数，该函数会产生诸如以下错误:

and then load the *.bc files, generate additional IR, and execute on the fly. The reason for the CUDA stuff is that I want to add some GPU acceleration to the runtime. However, this introduces CUDA specific external functions which gives errors such as:

LLVM ERROR: Program used external function 'cudaSetupArgument' which could not be resolved!

如此处所述， ，通常可以通过在编译程序时包含适当的库来解决:

As discussed here, this is usually solved by including the appropriate libraries when compiling the program:

g++ main.c cmal.o -L/usr/local/cuda/lib64 -lcudart 

但是，我不确定如何使用LLVM在JITed模块中包括库.我发现了这个问题，该问题过去曾经是可能的像这样将库添加到JIT中的模块:

However, I am not sure how to include libraries in JITed modules using LLVM. I found this question which suggested that is used to be possible to add libraries to modules in the JIT like this:

[your module]->addLibrary("m");

不幸的是，此方法已被弃用.谁能告诉我最好的方法吗?让我知道是否需要提供更多信息！

Unfortunately, this has been deprecated. Can anyone tell me the best way to do this now? Let me know if I need to provide more information!

此外，我不确定这是否是将GPU卸载整合到我的JIT中的最佳方法，因此，如果有人可以向我指出一种更好的方法，请执行:)

Furthermore, I am not really sure if this is the best way to be incorporating GPU offloading into my JIT, so if anyone can point me to a better method then please do :)

谢谢！

我正在使用LLVM 5.0，而我正在使用的JIT引擎来自llvm/ExecutionEngine/ExecutionEngine.h，更具体地说，我是这样创建的:

I am using LLVM 5.0 and the JIT engine I am using is from llvm/ExecutionEngine/ExecutionEngine.h, more specifically I create it like this:

EngineBuilder EB(std::move(module));
ExecutionEngine *EE = EB.create(targetMachine);

推荐答案

您需要明确地向JIT引擎学习其他符号.

You need to teach your JIT engine about other symbols explicitly.

如果它们在动态库(dylib，so，dll)中，则可以调用

If they are in a dynamic library (dylib, so, dll) then you can just call

sys::DynamicLibrary::LoadLibraryPermanently("path_to_some.dylib")

带有动态库的路径.

如果符号在目标文件或归档中，则需要做更多的工作:您需要将它们加载到内存中，并使用其API添加到ExecutionEngine中.

If the symbols are in an object file or an archive, then it requires a bit more work: you would need to load them into memory and add to the ExecutionEngine using its APIs.

以下是目标文件的示例:

Here is an example for an object file:

std::string objectFileName("some_object_file.o");

ErrorOr<std::unique_ptr<MemoryBuffer>> buffer =
  MemoryBuffer::getFile(objectFileName.c_str());

if (!buffer) {
  // handle error
}

Expected<std::unique_ptr<ObjectFile>> objectOrError =
  ObjectFile::createObjectFile(buffer.get()->getMemBufferRef());

if (!objectOrError) {
  // handle error
}

std::unique_ptr<ObjectFile> objectFile(std::move(objectOrError.get()));

auto owningObject = OwningBinary<ObjectFile>(std::move(objectFile),
                                             std::move(buffer.get()));

executionEngine.addObjectFile(std::move(owningObject));

对于档案，将模板类型ObjectFile替换为Archive，然后调用

For archives replace template types ObjectFile with Archive, and call

executionEngine.addArchive(std::move(owningArchive));

最后.

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