Help with Integrating LLVM

[jiezhuzzz]

Hi everyone, I have trouble integrating the LLVM package into my project. Here’s the segment I used in my CMakeLists.txt:

CPMAddPackage(
  NAME llvm
  VERSION 18.1.8
  URL https://github.com/llvm/llvm-project/releases/download/llvmorg-18.1.8/llvm-project-18.1.8.src.tar.xz
)

When I wrote the following code,

#include <llvm/IR/PassManager.h>
namespace llvm {

class HelloWorldPass : public PassInfoMixin<HelloWorldPass> {
public:
  PreservedAnalyses run(Function &F, FunctionAnalysisManager &AM);
};
} // namespace llvm

I got the following build output:

[build] <some_path_to_cpp_file>:2:10: fatal error: 'llvm/IR/PassManager.h' file not found
[build]     2 | #include <llvm/IR/PassManager.h>
[build]       |          ^~~~~~~~~~~~~~~~~~~~~~~
[build] 1 error generated.

Has anyone integrated LLVM into their project before? How did you set the configuration?

[Avus-c]

One immediate issue is that the llvm-project repository does not have a top-level CMakeLists.txt file. To resolve this, you need to use the SOURCE_SUBDIR argument to specify the location of the CMakeLists.txt file within the repository.

Since I am not deeply familiar with the llvm-project structure, there might be additional adjustments required.

[jiezhuzzz]

Hi Avus-c, thanks for your reply! I added the SOURCE_SUBDIR options, and now my project can automatically compile LLVM. However, I still cannot use LLVM APIs in my project. I checked the official LLVM documentation on how to embed LLVM with CMake, but the procedure seems different from the examples in the wiki.

I want to explore and add examples of installing LLVM to the wikis. However, I'm new to C++ and CMake. Would you mind giving me some hints on which part of the demo CMakeList I should refer to? Thanks!