https://github.com/mini-llvm/mini-llvm
A minimal implementation of the LLVM core libraries and tools
https://github.com/mini-llvm/mini-llvm
llvm
Last synced: 8 days ago
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A minimal implementation of the LLVM core libraries and tools
- Host: GitHub
- URL: https://github.com/mini-llvm/mini-llvm
- Owner: mini-llvm
- License: mit
- Created: 2024-10-01T02:54:48.000Z (over 1 year ago)
- Default Branch: main
- Last Pushed: 2026-06-06T07:29:19.000Z (12 days ago)
- Last Synced: 2026-06-06T09:13:37.936Z (12 days ago)
- Topics: llvm
- Language: C++
- Homepage: https://mini-llvm.github.io/mini-llvm/
- Size: 292 KB
- Stars: 15
- Watchers: 1
- Forks: 3
- Open Issues: 0
-
Metadata Files:
- Readme: README.md
- License: LICENSE
Awesome Lists containing this project
README
# mini-llvm
**A minimal implementation of the LLVM core libraries and tools**
| main | develop |
|:-:|:-:|
| [](https://github.com/mini-llvm/mini-llvm/actions/workflows/build.yml?query=branch%3Amain) | [](https://github.com/mini-llvm/mini-llvm/actions/workflows/build.yml?query=branch%3Adevelop) |
## Table of Contents
- [Overview](#overview)
- [Components](#components)
- [Highlights](#highlights)
- [Design](#design)
- [Features](#features)
- [Usage](#usage)
- [Build](#build)
- [Testing](#testing)
- [Installation](#installation)
- [References](#references)
- [License](#license)
## Overview
**mini-llvm** is a minimal implementation of the LLVM core libraries and tools, supporting a strict subset of LLVM IR constructs. It aims to demonstrate the essential principles of modern compiler design in a clear, concise, and approachable way.
## Components
- The mini-llvm core library (`libmini-llvm`)
- The `mini-llc` command-line tool
## Highlights
- Modern C++ (C++23)
- Cross-platform compatibility (Linux & Windows)
- Easy integration (CMake & Bazel)
- No external dependencies
## Design
## Features
### Supported Targets
- `riscv64`
Although `riscv64` is currently the only supported target, the flexible architecture design of mini-llvm enables adding new targets with minimal effort.
### Supported IR Constructs
#### Types
- `void`
- Integer types
- `i1`
- `i8`
- `i16`
- `i32`
- `i64`
- Floating-point types
- `float`
- `double`
- `ptr`
- Array types
- Function types
- `label`
#### Constants
- Integer constants
- Floating-point constants
- `null`
- Array constants
- `poison`
#### Instructions
- Terminators
- `br`
- `ret`
- Binary operators
- Integer
- Arithmetic
- `add`
- `sub`
- `mul`
- `sdiv`
- `udiv`
- `srem`
- `urem`
- `and`
- `or`
- `xor`
- `shl`
- `lshr`
- `ashr`
- Relational
- `icmp`
- Floating-point
- Arithmetic
- `fadd`
- `fsub`
- `fmul`
- `fdiv`
- `frem`
- Relational
- `fcmp`
- Unary operators
- Floating-point
- Arithmetic
- `fneg`
- Casting operators
- Integer
- `trunc`
- `sext`
- `zext`
- Floating-point
- `fptrunc`
- `fpext`
- Integer ↔️ Floating-point
- `sitofp`
- `uitofp`
- `fptosi`
- `fptoui`
- Pointer ↔️ Integer
- `ptrtoint`
- `inttoptr`
- `bitcast`
- Memory management
- `alloca`
- `load`
- `store`
- `getelemenetptr`
- Other
- `select`
- `call`
- `phi`
#### Attributes
- `alwaysinline`
- `argmemonly`
- `inaccessiblemem_or_argmemonly`
- `inaccessiblememonly`
- `noinline`
- `readnone`
- `readonly`
### Transform & Analysis Passes
#### IR-Level
- `AlgebraicSimplification`
- `ArrayFlattening`
- `AttributeDeduction`
- `BasicBlockMerging`
- `BranchSimplification`
- `ConstantFolding`
- `DeadCodeElimination`
- `DeadStoreElimination`
- `FunctionInlining`
- `GlobalCodeMotion`
- `GlobalDeadCodeElimination`
- `GlobalValueNumbering`
- `InstructionCombining`
- `JumpThreading`
- `Mem2Reg`
- `PoisonPropagation`
- `RedundantLoadElimination`
- `StrengthReduction`
- `TailCallElimination`
- `TailDuplication`
- `UnreachableBlockElimination`
- `AliasAnalysis`
- `DominatorTreeAnalysis`
- `LoopTreeAnalysis`
#### MIR-Level
- `BasicBlockMerging`
- `BasicBlockReordering`
- `CopyPropagation`
- `DeadCodeElimination`
- `JumpThreading`
- `NullOperationElimination`
- `RegisterReuse`
- `StackOffsetEvaluation`
- `TailDuplication`
- `UnreachableBlockElimination`
- `ZeroRegisterReplacement`
- `BranchPredictionAnalysis`
- `LiveVariableAnalysis`
- `RISCVConstantPropagation` (`riscv64`)
#### MC-Level
- `RISCVFallthrough` (`riscv64`)
- `RISCVUnusedLabelElimination` (`riscv64`)
### Register Allocators
- `GraphColoringAllocator`
- `LinearScanAllocator`
- `NaiveAllocator`
## Usage
main.ll
```llvm
@format = private constant [15 x i8] c"Hello, world!\0A\00"
declare i32 @printf(ptr, ...)
define i32 @main() {
0:
%1 = call i32 (ptr, ...) @printf(ptr @format)
ret i32 0
}
```
```sh
mini-llc --target riscv64 -o main.s main.ll
```
## Build
| Linux | macOS | Windows |
|:-:|:-:|:-:|
| ✅ | ✅ | ✅ |
| GCC | Clang | MSVC |
|:-:|:-:|:-:|
| ≥ 14 | ≥ 18 (libstdc++ ≥ 14, libc++ ❌*) | ≥ 19.42 (VS 2022 17.12) |
\* libc++ lacks support for certain C++23 features such as `std::move_only_function` and `std::views::enumerate`
| CMake | Bazel |
|:-:|:-:|
| ≥ 3.20 | ≥ 7.1 |
```sh
git clone --depth=1 --recurse-submodules --shallow-submodules
```
### With CMake
```sh
sudo apt-get update
sudo apt-get install -y g++-14 cmake ninja-build
cd
mkdir build && cd build
cmake -DCMAKE_CXX_COMPILER=g++-14 -DCMAKE_BUILD_TYPE=Release -DMINI_LLVM_TESTS=ON -G Ninja ..
cmake --build .
./tools/mini-llc/mini-llc --help
```
| Build Option | Default | Description |
| - | - | - |
| `BUILD_SHARED_LIBS` | `OFF` | Build mini-llvm as a shared library (libmini-llvm.so) |
| `MINI_LLVM_TESTS` | `OFF` | Build tests |
| `MINI_LLVM_FUZZ` | `OFF` | Build fuzz targets |
| `MINI_LLVM_DOCS` | `OFF` | Build docs (requires Doxygen and Graphviz) |
### With Bazel
```sh
sudo apt-get update
sudo apt-get install -y g++-14
# Install Bazel: https://bazel.build/install/ubuntu
cd
CC=gcc-14 CXX=g++-14 bazel build -c opt //...
./bazel-bin/tools/mini-llc/mini-llc --help
```
| Build Option | Default | Description |
| - | - | - |
| `--//:shared` | `false` | Build mini-llvm as a shared library (libmini-llvm.so) |
## Testing
### Unit Tests
```sh
# CMake
cd /build
ctest
# Bazel
cd
CC=gcc-14 CXX=g++-14 bazel test -c opt //unittests:unittests
```
### Integration Tests
```sh
sudo apt-get update
sudo apt-get install -y gcc-riscv64-linux-gnu qemu-user
sudo mkdir -p /usr/gnemul
sudo ln -s /usr/riscv64-linux-gnu /usr/gnemul/qemu-riscv64
cd /tests/mini-llc
# CMake
./test_all.sh \
--mini-llc ../../build/bin/mini-llc \
--target riscv64 \
--driver riscv64-linux-gnu-gcc \
--emulator qemu-riscv64
# Bazel
./test_all.sh \
--mini-llc ../../bazel-bin/tools/mini-llc/mini-llc \
--target riscv64 \
--driver riscv64-linux-gnu-gcc \
--emulator qemu-riscv64
```
## Installation
```sh
# CMake
cd /build
cmake --install .
```
## References
- LLVM Language Reference Manual. https://llvm.org/docs/LangRef.html
- Cliff Click. 1995. Global code motion/global value numbering. In *Proceedings of the ACM SIGPLAN 1995 Conference on Programming Language Design and Implementation* (PLDI '95). Association for Computing Machinery, New York, NY, USA, 246–257. https://doi.org/10.1145/207110.207154
- Ron Cytron, Jeanne Ferrante, Barry K. Rosen, Mark N. Wegman, and F. Kenneth Zadeck. 1991. Efficiently computing static single assignment form and the control dependence graph. *ACM Trans. Program. Lang. Syst.* 13, 4 (Oct. 1991), 451–490. https://doi.org/10.1145/115372.115320
- Torbjörn Granlund and Peter L. Montgomery. 1994. Division by invariant integers using multiplication. In *Proceedings of the ACM SIGPLAN 1994 Conference on Programming Language Design and Implementation* (PLDI '94). Association for Computing Machinery, New York, NY, USA, 61–72. https://doi.org/10.1145/178243.178249
- Thomas Lengauer and Robert Endre Tarjan. 1979. A fast algorithm for finding dominators in a flowgraph. *ACM Trans. Program. Lang. Syst.* 1, 1 (Jan. 1979), 121–141. https://doi.org/10.1145/357062.357071
- Massimiliano Poletto and Vivek Sarkar. 1999. Linear scan register allocation. *ACM Trans. Program. Lang. Syst.* 21, 5 (Sept. 1999), 895–913. https://doi.org/10.1145/330249.330250
## License
mini-llvm is licensed under the [MIT license](https://opensource.org/licenses/MIT).