This project transpiles LLVM IR to .NET CIL.

Clang Compilation Options

While this project is intended to handle any LLVM IR, it works best when the input is generated on Windows with the following Clang command:

clang -g -fno-discard-value-names -fstandalone-debug -S -emit-llvm -o {outputFile} {inputFile}

This ensures that debug information is included and that parameter names are preserved, which helps with generating code that is more readable.

Large Projects with CMake on Windows

Install Ninja

Use ninja --version to verify that it's been added to the PATH.

Create `clang-msvc.cmake`

It should be placed in the same directory as the C++ source files and contain the following:

set(CMAKE_SYSTEM_NAME Windows)
set(CMAKE_SYSTEM_PROCESSOR x86_64)

set(CMAKE_C_COMPILER "clang-cl")
set(CMAKE_CXX_COMPILER "clang-cl")

set(CMAKE_LINKER "lld-link")

Run CMake

cmake -G "Ninja" \
  -S ./path-to-directory-with-source-files/ \
  -B ./path-to-build-output-directory/ \
  -DCMAKE_TOOLCHAIN_FILE=./clang-msvc.cmake \
  -DCMAKE_C_FLAGS_DEBUG="-g -fno-discard-value-names -fstandalone-debug -emit-llvm -w" \
  -DCMAKE_CXX_FLAGS_DEBUG="-g -fno-discard-value-names -fstandalone-debug -emit-llvm -w" \
  -DCMAKE_EXPORT_COMPILE_COMMANDS=ON

This will generate a compile_commands.json file in the build output directory, which is necessary for the next step.

Flags

-g ensures that debug information is included.
-fno-discard-value-names preserves parameter names in the generated LLVM IR.
-fstandalone-debug ensures that the debug information is self-contained.
-emit-llvm generates LLVM IR instead of object files.
-w suppresses warnings, which can be useful for large projects.

Compile the project

LargeProjectCompiler.exe ./path-to/compile_commands.json

Use --help to see additional options.

66hh/AssetRipper.Translation.LlvmIR