reopt
Reopt is a tool under development for decompiling and recompiling
code. It works by mapping binaries into LLVM byte code, using the
LLVM optimization passes to optimize the LLVM, and then combining the
newly generated into the binary to generate a new executable.
Reopt supports the x86_64 instruction set, and is still under active
development -- bugs are expected.
We have recently updated Reopt to make it easier to use specific
capabilities within the tool. The main capabilities are described
below. Additional options can be viewed by running reopt --help.
-
Disassembly.
reopt -d <binary>provides a raw disassembler output view
of the code in the binary. This is similiar toobjdump's disassembly
output. -
Control flow graph construction.
reopt --cfg <binary>displays the low
level control flow graphs that Reopt has constructed for each discovered
function within the binary. This is a low-level IR that maintains
machine code's explicit stack and register references, but lifts the
machine code instructions into a more architectural neutral register
transfer language. -
Function Recovery
reopt --fns <binary>displays the functions that Reopt
has generated after performing stack and function argument analysis. This
is a higher-level IR in which explicit references to the stack have been
replaced with allocations, and functions take arguments. -
LLVM Generation
reopt --llvm <binary>generates LLVM from the binary. This
is essentially a version of function recovery rendered in LLVM's format. -
Object Files
reopt --object <binary>generates an object file from the
LLVM generated in the previous state. This is essentially the same as
generating the LLVM, and then running the LLVM compiler toolchain with
the selected options. The output file should be specified with the
-oflag as object files cannot be written to standard out. -
Recompilation
reopt <binary>runs the full recompilation toolchain
and produces a new binary equialent to the original.
The are additional options that can be viewed by running reopt --help. More documentation will be provided once the tool is in a
more mature state.
Installation
If you have git and Haskell stack, you should be able to install
with:
git submodule update --init
stack install reopt