forked from cerc-io/plugeth
342ae7ce7d
The EVM was previously initialised and created for every CALL, CALLCODE, DELEGATECALL and CREATE. This PR changes this behaviour so that the same EVM can be used through the session and beyond as long as the Environment sticks around.
125 lines
3.5 KiB
Go
125 lines
3.5 KiB
Go
// Copyright 2014 The go-ethereum Authors
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// This file is part of the go-ethereum library.
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//
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// The go-ethereum library is free software: you can redistribute it and/or modify
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// it under the terms of the GNU Lesser General Public License as published by
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// the Free Software Foundation, either version 3 of the License, or
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// (at your option) any later version.
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//
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// The go-ethereum library is distributed in the hope that it will be useful,
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// but WITHOUT ANY WARRANTY; without even the implied warranty of
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// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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// GNU Lesser General Public License for more details.
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//
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// You should have received a copy of the GNU Lesser General Public License
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// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
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package vm
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import (
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"math"
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"math/big"
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"github.com/ethereum/go-ethereum/common"
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"github.com/ethereum/go-ethereum/params"
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)
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// Global Debug flag indicating Debug VM (full logging)
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var Debug bool
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var GenerateStructLogs bool = false
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// Type is the VM type accepted by **NewVm**
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type Type byte
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const (
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StdVmTy Type = iota // Default standard VM
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JitVmTy // LLVM JIT VM
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MaxVmTy
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)
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var (
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Pow256 = common.BigPow(2, 256) // Pow256 is 2**256
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U256 = common.U256 // Shortcut to common.U256
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S256 = common.S256 // Shortcut to common.S256
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Zero = common.Big0 // Shortcut to common.Big0
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One = common.Big1 // Shortcut to common.Big1
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max = big.NewInt(math.MaxInt64) // Maximum 64 bit integer
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)
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// calculates the memory size required for a step
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func calcMemSize(off, l *big.Int) *big.Int {
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if l.Cmp(common.Big0) == 0 {
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return common.Big0
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}
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return new(big.Int).Add(off, l)
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}
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// calculates the quadratic gas
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func quadMemGas(mem *Memory, newMemSize, gas *big.Int) {
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if newMemSize.Cmp(common.Big0) > 0 {
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newMemSizeWords := toWordSize(newMemSize)
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newMemSize.Mul(newMemSizeWords, u256(32))
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if newMemSize.Cmp(u256(int64(mem.Len()))) > 0 {
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// be careful reusing variables here when changing.
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// The order has been optimised to reduce allocation
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oldSize := toWordSize(big.NewInt(int64(mem.Len())))
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pow := new(big.Int).Exp(oldSize, common.Big2, Zero)
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linCoef := oldSize.Mul(oldSize, params.MemoryGas)
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quadCoef := new(big.Int).Div(pow, params.QuadCoeffDiv)
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oldTotalFee := new(big.Int).Add(linCoef, quadCoef)
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pow.Exp(newMemSizeWords, common.Big2, Zero)
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linCoef = linCoef.Mul(newMemSizeWords, params.MemoryGas)
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quadCoef = quadCoef.Div(pow, params.QuadCoeffDiv)
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newTotalFee := linCoef.Add(linCoef, quadCoef)
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fee := newTotalFee.Sub(newTotalFee, oldTotalFee)
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gas.Add(gas, fee)
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}
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}
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}
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// Simple helper
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func u256(n int64) *big.Int {
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return big.NewInt(n)
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}
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// Mainly used for print variables and passing to Print*
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func toValue(val *big.Int) interface{} {
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// Let's assume a string on right padded zero's
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b := val.Bytes()
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if b[0] != 0 && b[len(b)-1] == 0x0 && b[len(b)-2] == 0x0 {
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return string(b)
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}
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return val
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}
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// getData returns a slice from the data based on the start and size and pads
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// up to size with zero's. This function is overflow safe.
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func getData(data []byte, start, size *big.Int) []byte {
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dlen := big.NewInt(int64(len(data)))
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s := common.BigMin(start, dlen)
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e := common.BigMin(new(big.Int).Add(s, size), dlen)
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return common.RightPadBytes(data[s.Uint64():e.Uint64()], int(size.Uint64()))
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}
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// useGas attempts to subtract the amount of gas and returns whether it was
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// successful
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func useGas(gas, amount *big.Int) bool {
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if gas.Cmp(amount) < 0 {
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return false
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}
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// Sub the amount of gas from the remaining
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gas.Sub(gas, amount)
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return true
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}
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