# Building Slang From Source ### TLDR `cmake --workflow --preset release` to configure, build, and package a release version of Slang. ## Prerequisites: Please install: - CMake - A C++ compiler with support for C++17. GCC, Clang and MSVC are supported - A CMake compatible backend, for example Visual Studio or Ninja Optional dependencies include - CUDA - OptiX - NVAPI - Aftermath - X11 ## Get the Source Code Clone [this](https://github.com/shader-slang/slang) repository. Make sure to fetch the submodules also. ```bash git clone https://github.com/shader-slang/slang --recursive ``` ## Configure and build For a Ninja based build system (all platforms) run: ```bash cmake --preset default cmake --build --preset release # or --preset debug ``` For Visual Studio run: ```bash cmake --preset vs2022 # or 'vs2019' or `vs2022-dev` start devenv ./build/slang.sln # to optionally open the project in Visual Studio cmake --build --preset release # to build from the CLI ``` The `vs2022-dev` preset turns on features that makes debugging easy. ## Testing ```bash build/Debug/bin/slang-test ``` See the [documentation on testing](../tools/slang-test/README.md) for more information. ## More niche topics ### CMake options | Option | Default | Description | |-----------------------------------|------------------|--------------------------------------------------------------------| | `SLANG_VERSION` | Latest `v*` tag | The project version, detected using git if available | | `SLANG_EMBED_STDLIB` | `FALSE` | Build slang with an embedded version of the stdlib | | `SLANG_EMBED_STDLIB_SOURCE` | `TRUE` | Embed stdlib source in the binary | | `SLANG_ENABLE_ASAN` | `FALSE` | Enable ASAN (address sanitizer) | | `SLANG_ENABLE_FULL_IR_VALIDATION` | `FALSE` | Enable full IR validation (SLOW!) | | `SLANG_ENABLE_IR_BREAK_ALLOC` | `FALSE` | Enable IR BreakAlloc functionality for debugging. | | `SLANG_ENABLE_GFX` | `TRUE` | Enable gfx targets | | `SLANG_ENABLE_SLANGD` | `TRUE` | Enable language server target | | `SLANG_ENABLE_SLANGC` | `TRUE` | Enable standalone compiler target | | `SLANG_ENABLE_SLANGRT` | `TRUE` | Enable runtime target | | `SLANG_ENABLE_SLANG_GLSLANG` | `TRUE` | Enable glslang dependency and slang-glslang wrapper target | | `SLANG_ENABLE_TESTS` | `TRUE` | Enable test targets, requires SLANG_ENABLE_GFX, SLANG_ENABLE_SLANGD and SLANG_ENABLE_SLANGRT | | `SLANG_ENABLE_EXAMPLES` | `TRUE` | Enable example targets, requires SLANG_ENABLE_GFX | | `SLANG_LIB_TYPE` | `SHARED` | How to build the slang library | | `SLANG_SLANG_LLVM_FLAVOR` | `FETCH_BINARY` | How to set up llvm support | | `SLANG_SLANG_LLVM_BINARY_URL` | System dependent | URL specifying the location of the slang-llvm prebuilt library | | `SLANG_GENERATORS_PATH` | `` | Path to an installed `all-generators` target for cross compilation | The following options relate to optional dependencies for additional backends and running additional tests. Left unchanged they are auto detected, however they can be set to `OFF` to prevent their usage, or set to `ON` to make it an error if they can't be found. | Option | CMake hints | Notes | |--------------------------|--------------------------------|---------------------------------------------------------------------| | `SLANG_ENABLE_CUDA` | `CUDAToolkit_ROOT` `CUDA_PATH` | | | `SLANG_ENABLE_OPTIX` | `Optix_ROOT_DIR` | Requires CUDA | | `SLANG_ENABLE_NVAPI` | `NVAPI_ROOT_DIR` | Only available for builds targeting Windows | | `SLANG_ENABLE_AFTERMATH` | `Aftermath_ROOT_DIR` | Enable Aftermath in GFX, and add aftermath crash example to project | | `SLANG_ENABLE_XLIB` | | | ### LLVM Support There are several options for getting llvm-support: - Use a prebuilt binary slang-llvm library: `-DSLANG_SLANG_LLVM_FLAVOR=FETCH_BINARY`, this is the default - You can set `SLANG_SLANG_LLVM_BINARY_URL` to point to a local `libslang-llvm.so/slang-llvm.dll` or set it to a URL of an zip/archive containing such a file - Use a system supplied LLVM: `-DSLANG_SLANG_LLVM_FLAVOR=USE_SYSTEM_LLVM`, you must have llvm-13.0 and a matching libclang installed. It's important that either: - You don't end up linking to a dynamic libllvm.so, this will almost certainly cause multiple versions of LLVM to be loaded at runtime, leading to errors like `opt: CommandLine Error: Option 'asm-macro-max-nesting-depth' registered more than once!`. Avoid this by compiling LLVM without the dynamic library. - Anything else which may be linked in (for example Mesa, also dynamically loads the same llvm object) - Have the Slang build system build LLVM: `-DSLANG_SLANG_LLVM_FLAVOR=BUILD_LLVM`, this will build LLVM binaries at configure time and use that. This is only intended to be used as part of the process of generating the portable binary slang-llvm library. This always builds a `Release` LLVM, so is unsuitable to use when building a `Debug` `slang-llvm` on Windows as the runtime libraries will be incompatible. - Do not enable LLVM support: `-DSLANG_SLANG_LLVM_FLAVOR=DISABLE` To build only a standalone slang-llvm, you can run: ```bash cmake --workflow --preset slang-llvm ``` This will generate `build/dist-release/slang-slang-llvm.zip` containing the library. This, of course, uses the system LLVM to build slang-llvm, otherwise it would just be a convoluted way to download a prebuilt binary. ### Cross compiling Slang generates some code at build time, using generators build from this codebase. Due to this, for cross compilation one must already have built these generators for the build platform. Build them with the `generators` preset, and pass the install path to the cross building CMake invocation using `SLANG_GENERATORS_PATH` ```bash # build the generators cmake --workflow --preset generators --fresh mkdir my-build-platform-generators cmake --install build --config Release --prefix my-build-platform-generators --component generators # reconfigure, pointing to these generators # Here is also where you should set up any cross compiling environment cmake \ --preset default \ --fresh \ -DSLANG_GENERATORS_PATH=my-build-platform-generators/bin \ -Dwhatever-other-necessary-options-for-your-cross-build # perform the final build cmake --workflow --preset release ``` ### Example cross compiling with MSVC to windows-aarch64 One option is to build using the ninja generator, which requires providing the native and cross environments via `vcvarsall.bat` ```bash vcvarsall.bat cmake --workflow --preset generators --fresh mkdir generators cmake --install build --prefix generators --component generators vsvarsall.bat x64_arm64 cmake --preset default --fresh -DSLANG_GENERATORS_PATH=generators/bin cmake --workflow --preset release ``` Another option is to build using the Visual Studio generator which can find this automatically ``` cmake --preset vs2022 # or --preset vs2019 cmake --build --preset generators # to build from the CLI cmake --install build --prefix generators --component generators rm -rf build # The Visual Studio generator will complain if this is left over from a previous build cmake --preset vs2022 --fresh -A arm64 -DSLANG_GENERATORS_PATH=generators/bin cmake --build --preset release ```