unnamedd / LLVMPlayground

Small sample programs that use LLVM and Clang APIs.

LLVMPlayground

This is a CMake project I use to experiment with LLVM and Clang libraries, by writing small example programs that use them.

To use it yourself:

git clone https://github.com/modocache/LLVMPlayground.git
make -C LLVMPlayground

The example programs are in LLVMPlayground/build/playground. For example, to run a program that uses llvm::MemoryBuffer, run:

./LLVMPlayground/build/playground/memorybuffer

To add your own example program, add a call to add_playground_executable to the CMakeLists.txt file.

How this project is built

The source files in this LLVMPlayground repository are configured and built using CMake. As explained in this article, LLVM, Clang, and Swift also use CMake.

Projects that use CMake require two invocations of the cmake executable: one to configure the project, and one to build it based on that configuration.

The Makefile in this project handles this "configure and then build" dance for LLVM and Clang, and then for this LLVMPlayground project itself. Running make does the following:

1. Clones LLVM and Clang as Git submodules, placing them in the external directory.
2. Runs cmake in order to configure the LLVM project. LLVM's CMake allows Clang to be configured as well, by using its LLVM_ENABLE_PROJECTS CMake option.
3. Runs cmake --build in order to build LLVM and Clang.
4. Runs cmake in order to configure the LLVMPlayground project. When configuring, the Makefile passes in the paths to LLVM and Clang CMake files. This allows the LLVMPlayground executables to be linked against LLVM and Clang libraries.
5. Runs cmake --build in order to build the executables in LLVMPlayground.