go-ethereum/cmd/disasm/main.go

// Copyright 2015 The go-ethereum Authors
// This file is part of go-ethereum.
//
// go-ethereum is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// go-ethereum is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU General Public License for more details.
//
// You should have received a copy of the GNU General Public License
// along with go-ethereum. If not, see <http://www.gnu.org/licenses/>.

// disasm is a pretty-printer for EVM bytecode.
package main

import (
	"encoding/hex"
	"fmt"
	"io/ioutil"
	"os"
	"strings"

	"github.com/ethereum/go-ethereum/core/vm"
)

func main() {
	code, err := ioutil.ReadAll(os.Stdin)
	if err != nil {
		fmt.Println(err)
		os.Exit(1)
	}
	code, err = hex.DecodeString(strings.TrimSpace(string(code[:])))
	if err != nil {
		fmt.Printf("Error: %v\n", err)
		return
	}
	fmt.Printf("%x\n", code)

	for pc := uint64(0); pc < uint64(len(code)); pc++ {
		op := vm.OpCode(code[pc])

		switch op {
		case vm.PUSH1, vm.PUSH2, vm.PUSH3, vm.PUSH4, vm.PUSH5, vm.PUSH6, vm.PUSH7, vm.PUSH8, vm.PUSH9, vm.PUSH10, vm.PUSH11, vm.PUSH12, vm.PUSH13, vm.PUSH14, vm.PUSH15, vm.PUSH16, vm.PUSH17, vm.PUSH18, vm.PUSH19, vm.PUSH20, vm.PUSH21, vm.PUSH22, vm.PUSH23, vm.PUSH24, vm.PUSH25, vm.PUSH26, vm.PUSH27, vm.PUSH28, vm.PUSH29, vm.PUSH30, vm.PUSH31, vm.PUSH32:
			a := uint64(op) - uint64(vm.PUSH1) + 1
			u := pc + 1 + a
			if uint64(len(code)) <= pc || uint64(len(code)) < u {
				fmt.Printf("Error: incomplete push instruction at %v\n", pc)
				return
			}
			fmt.Printf("%-5d  %v  => %x\n", pc, op, code[pc+1:u])
			pc += a
		default:
			fmt.Printf("%-5d  %v\n", pc, op)
		}
	}
}