A disassembler for the Fuel VM byte code.
The forc utility provides a parse-bytecode command which will print a bare-bones disassembly with
the raw values decoded from a contract's binary bytecode. It is limited by assuming that every
32-bit word is an executable instruction, although it does attempt to output some helpful comments
where it can. But generally it is quite hard to read.
forc-dis attempts to produces a far more readable disassembly. It will follow the control flow
from the entry point, making no assumptions about whether decoded bytes are instructions or data.
It also gives readable names to registers, annotates locations which are read by memory instructions
and names known constant values used by the VM.
It also syntax highlights the listing in a fairly pleasing colour scheme.
cargo install forc-dis
Clone this repository and build with Cargo as usual.
git clone https://github.com/otrho/fuel-dis.git
cd fuel-dis
cargo build --release
It can then be run in place using cargo run --release. Or it can be installed using cargo
install --path ..
forc-dis will take the path to the bytecode binary as a command line argument.
Alternatively, if forc-dis is in your path it may be used as a Forc plugin. From within a Forc
project it can be invoked using forc dis, in which case it will attempt to find the bytecode
binary automatically.
``` $ forc new example
To compile, use forc build, and to run tests use forc test
Read the Docs: - Sway Book: https://fuellabs.github.io/sway/latest - Rust SDK Book: https://fuellabs.github.io/fuels-rs/latest - TypeScript SDK: https://github.com/FuelLabs/fuels-ts
Join the Community: - Follow us @SwayLang: https://twitter.com/SwayLang - Ask questions in dev-chat on Discord: https://discord.com/invite/xfpK4Pe
Report Bugs: - Sway Issues: https://github.com/FuelLabs/sway/issues/new
$ cd example/ $ cat src/main.sw contract;
abi MyContract { fn test_function() -> bool; }
impl MyContract for Contract { fn test_function() -> bool { true } }
$ forc build
Creating a new Forc.lock file. (Cause: lock file did not exist)
Adding core
Adding std git+https://github.com/fuellabs/sway...
Created new lock file at...
Compiled library "core".
Compiled library "std".
Compiled contract "example".
Bytecode size is 60 bytes.
$ forc dis 00000000 ji block_0010
00000004 47 00 00 00 G...
00000008 WORD 0000000000000034h ; load @ 00000010
00000010 block0010: ; from 00000000 00000010 lw $ds $is 1 ; $ds = 0000000000000034h 00000014 add $ds $ds $is 00000018 lw $r0 $fp 73 0000001c lw $r1 $ds 0 ; $r1 = 000000002151bd4bh 00000020 eq $r2 $r0 $r1 00000024 jnzi $r2 block0030 00000028 movi $tmp 123 0000002c rvrt $tmp
00000030 block_0030: ; from 00000024 00000030 ret $one
00000034 DATA SECTION: 00000034 WORD 000000002151bd4bh ; load @ 0000001c ```