Reaver C Compiler

Reaver C Compiler (rcc) is a C99 compiler. It features a lexer, parser, preprocessor, AST, and compiles to LLVM IR. It supports both x86 and AArch64.

Why?

For fun! We started v1.0 as part of our 2nd year IAC coursework at Imperial College London. Then, to learn about LLVM, I decided to rewrite the entire compiler. For more information on the evolution from v1.0, please read info.md.

The code here can be used as a guide to get started on writing an LLVM based toy compiler.

Getting started

Note

This has been tested only on Linux (x86-64) and Mac (AArch64). There is no planned support for Windows or other architectures.

Dependencies

Reaver C Compiler relies on the following dependencies:

• LLVM
• CLI11
• Boost
• GTest

It also relies on the following tools:

• CMake 3.20+
• Clang (if linking is required)
• Git
• Ninja
• Python
• Flex
• Bison 3.0+

Building from source

1. [Optional] Clone the external repos into a folder called third_party. This will take some time. It is possible to use the latest branch, however, the compiler has only been tested on these versions.

mkdir third_party
git -C third_party clone --branch llvmorg-20.1.5 [email protected]:llvm/llvm-project.git
git -C third_party clone --branch boost-1.88.0 --recursive [email protected]:boostorg/boost.git
git -C third_party clone --branch v2.5.0 [email protected]:CLIUtils/CLI11.git
git -C third_party clone --branch v1.17.0 [email protected]:google/googletest.git

2. Run CMake.

mkdir build
cd build
cmake .. \
    -G Ninja \
    -DFETCHCONTENT_SOURCE_DIR_LLVM_PROJECT=../third_party/llvm-project \
    -DFETCHCONTENT_SOURCE_DIR_BOOST=../third_party/boost \
    -DFETCHCONTENT_SOURCE_DIR_CLI11=../third_party/CLI11 \
    -DFETCHCONTENT_SOURCE_DIR_GOOGLETEST=../third_party/googletest
ninja

Usage

To run the compiler, run the following command, replacing the flags,

• -o for the output file path

For example, this will compile the example program:

build/rcc ./tests/_example/example.c -o ./example.o

Then, invoke your linker to link the object file.

clang ./tests/_example/example_driver.c example.o

Running Unit Tests

To run all unit tests, run the following commands:

cd build
ctest

Running Integration Tests

To run the provided integration tests, run the following command:

./test.py

To run the additional integration tests, run the following commands:

# Only run this once
git submodule update --init --recursive
# More options available. Does not pass all tests yet
./writing-a-c-compiler-tests/test_compiler --chapter 18 --skip-invalid build/rcc

Credits

• William Huynh
• Kevin Lau

References

C99 standard: https://port70.net/%7Ensz/c/c99/n1256.html