unidecompiler

unidecompiler is the frontend-neutral core for universal bytecode decompilation. It owns thin-IR lifting, recovery, generic IR, diagnostics, AST generation, and the stable DecompilerEngine facade used by CLI, GUI, and frontend plugin packages.

Frontend plugins decode VM-specific formats and submit neutral bytecode facts; they do not perform source-structure recovery.

The core may also carry optional ByteRange provenance for exact, absolute locations in the original input artifact. This is read-only presentation data for hosts such as the GUI; it has no execution, control-flow, or recovery semantics and is omitted whenever the decoder cannot prove the range.

Core recovery reaches a fixed point before the final AST is emitted:

thin IR -> generic IR / low-level CFG
                 |
                 v
          CFG structuring
                 |
                 v
  structured FunctionIR refinement
          |                 |
       changed            stable
          |                 |
          +--> CFG analysis/structuring ↺
                              |
                              v
                   final AST -> backend rendering

recovery_refinement.py owns the VM-neutral refinement loop. It accepts only rewrites that preserve the verified CFG and safety invariants; otherwise the existing low-level CFG/goto representation remains the preservation floor. The loop operates on structured FunctionIR inside core. It is not a frontend-specific pass, and backends do not infer or recover control flow.

CFG rewrites are edge-aware. Parallel edges retain deterministic concrete identity, and shared CFG analysis snapshots provide graph facts for structuring. Same-value Phi cleanup and explicit fallthrough-jump removal are performed only when predecessor edges, exception state, data-flow values, and evaluation order are proven equivalent. If that proof is unavailable, core keeps the low-level CFG/goto form rather than guessing.

Install

Install the core library directly from PyPI. Cloning this repository is not required for normal use:

python -m pip install unidecompiler

To decompile an artifact, also install a host such as unidecompiler-cli or unidecompiler-gui and the frontend plugin for the bytecode format you need.