The Ballistic JIT Engine

„The world's fastest ARM recompiler“

Overview

This is a rewrite of the dynarmic recompiler, with the goal of fixing its many flaws.

CPU Cache Constraints

Ballistic is being designed to have an extremely low Cache Footprint:

1. L1d: 4 KB
2. L2: 30 KB

Version 1.0 Goals

• Create Tier 1 backend compiler.
• Create Tier 2 backend compiler.
• Support MOVZ, MOVK, MOVN instructions on both compilers.
• Support decoding ARM32 instructions.
• Treat PACISAP and AUTISAP as NOP then strip the upper bits of X30.
• Add more peephole optimizations.
• Have 100% branch coverage.
• Have a config to change Ballistic behavior at runtime.
• Support Block linking.
• Map ARM flags to x86 flags.
• Support 128-bit types and x86 SSE/AVX instructions.
• Add exception handling and recover guest CPU state.
• Add register spilling.
• Add Software Page Tables for MMIO and expose the page table memory layout.
• Handle Guest W^X and Guest RO/RW.
• Support Guest Write permissions and MMIO write traps for bal_translate_write_function_t.
• Allow the Guest to inform the memory subsystem that a Guest page has changed state.
• Invalidate JIT caches when Guest memory is modified using bal_invalidate_git_cache_function_t.
• Trap cache maintanence instructions then invalidate the block cache at that GVA.
• Track multiple address spaces with ASIDs.
• Handle memory aliasing and cache attributes (CPU: Cached, GPU: Cached/Write-Combining)
• Rewrite tools/cdoc.c
• Rewrite all Python scripts in Lua.
• Add code examples on how to use a header file like in bal_x86_sliding_window.h.
• Reorganize all functions in alphabetical order in .c and .h files.
• Add benchmarks measuring compilation speed compared to other JIT compilers.

Building Ballistic

Install Dependencies

macOS

brew install cmake python3 llvm

Debian/Ubuntu

sudo apt update
sudo apt install build-essential cmake python3

Fedora

sudo dnf install cmake python3 gcc-c++

Configure CMake

mkdir build
cd build
cmake ..

Build Binaries

cmake --build .

The compiled executables will be created in the build/bin and build/lib directories.

See tools/ for more information on these executables.