all: unify big.Int zero checks, use common/math in more places (#3716)

* common/math: optimize PaddedBigBytes, use it more

name              old time/op    new time/op    delta
PaddedBigBytes-8    71.1ns ± 5%    46.1ns ± 1%  -35.15%  (p=0.000 n=20+19)

name              old alloc/op   new alloc/op   delta
PaddedBigBytes-8     48.0B ± 0%     32.0B ± 0%  -33.33%  (p=0.000 n=20+20)

* all: unify big.Int zero checks

Various checks were in use. This commit replaces them all with Int.Sign,
which is cheaper and less code.

eg templates:

    func before(x *big.Int) bool { return x.BitLen() == 0 }
    func after(x *big.Int) bool  { return x.Sign() == 0 }

    func before(x *big.Int) bool { return x.BitLen() > 0 }
    func after(x *big.Int) bool  { return x.Sign() != 0 }

    func before(x *big.Int) int { return x.Cmp(common.Big0) }
    func after(x *big.Int) int  { return x.Sign() }

* common/math, crypto/secp256k1: make ReadBits public in package math
This commit is contained in:
Felix Lange
2017-02-28 15:09:11 +01:00
committed by Jeffrey Wilcke
parent d4f60d362b
commit 5f7826270c
30 changed files with 104 additions and 114 deletions

View File

@ -25,7 +25,7 @@ import (
// calculates the memory size required for a step
func calcMemSize(off, l *big.Int) *big.Int {
if l.Cmp(common.Big0) == 0 {
if l.Sign() == 0 {
return common.Big0
}

View File

@ -120,7 +120,7 @@ func (evm *EVM) Call(caller ContractRef, addr common.Address, input []byte, gas
snapshot = evm.StateDB.Snapshot()
)
if !evm.StateDB.Exist(addr) {
if PrecompiledContracts[addr] == nil && evm.ChainConfig().IsEIP158(evm.BlockNumber) && value.BitLen() == 0 {
if PrecompiledContracts[addr] == nil && evm.ChainConfig().IsEIP158(evm.BlockNumber) && value.Sign() == 0 {
return nil, gas, nil
}

View File

@ -273,7 +273,7 @@ func gasExp(gt params.GasTable, evm *EVM, contract *Contract, stack *Stack, mem
func gasCall(gt params.GasTable, evm *EVM, contract *Contract, stack *Stack, mem *Memory, memorySize uint64) (uint64, error) {
var (
gas = gt.Calls
transfersValue = stack.Back(2).BitLen() > 0
transfersValue = stack.Back(2).Sign() != 0
address = common.BigToAddress(stack.Back(1))
eip158 = evm.ChainConfig().IsEIP158(evm.BlockNumber)
)
@ -316,7 +316,7 @@ func gasCall(gt params.GasTable, evm *EVM, contract *Contract, stack *Stack, mem
func gasCallCode(gt params.GasTable, evm *EVM, contract *Contract, stack *Stack, mem *Memory, memorySize uint64) (uint64, error) {
gas := gt.Calls
if stack.Back(2).BitLen() > 0 {
if stack.Back(2).Sign() != 0 {
gas += params.CallValueTransferGas
}
memoryGas, err := memoryGasCost(mem, memorySize)
@ -362,7 +362,7 @@ func gasSuicide(gt params.GasTable, evm *EVM, contract *Contract, stack *Stack,
if eip158 {
// if empty and transfers value
if evm.StateDB.Empty(address) && evm.StateDB.GetBalance(contract.Address()).BitLen() > 0 {
if evm.StateDB.Empty(address) && evm.StateDB.GetBalance(contract.Address()).Sign() != 0 {
gas += gt.CreateBySuicide
}
} else if !evm.StateDB.Exist(address) {

View File

@ -58,7 +58,7 @@ func opMul(pc *uint64, evm *EVM, contract *Contract, memory *Memory, stack *Stac
func opDiv(pc *uint64, evm *EVM, contract *Contract, memory *Memory, stack *Stack) ([]byte, error) {
x, y := stack.pop(), stack.pop()
if y.Cmp(common.Big0) != 0 {
if y.Sign() != 0 {
stack.push(math.U256(x.Div(x, y)))
} else {
stack.push(new(big.Int))
@ -71,12 +71,12 @@ func opDiv(pc *uint64, evm *EVM, contract *Contract, memory *Memory, stack *Stac
func opSdiv(pc *uint64, evm *EVM, contract *Contract, memory *Memory, stack *Stack) ([]byte, error) {
x, y := math.S256(stack.pop()), math.S256(stack.pop())
if y.Cmp(common.Big0) == 0 {
if y.Sign() == 0 {
stack.push(new(big.Int))
return nil, nil
} else {
n := new(big.Int)
if evm.interpreter.intPool.get().Mul(x, y).Cmp(common.Big0) < 0 {
if evm.interpreter.intPool.get().Mul(x, y).Sign() < 0 {
n.SetInt64(-1)
} else {
n.SetInt64(1)
@ -93,7 +93,7 @@ func opSdiv(pc *uint64, evm *EVM, contract *Contract, memory *Memory, stack *Sta
func opMod(pc *uint64, evm *EVM, contract *Contract, memory *Memory, stack *Stack) ([]byte, error) {
x, y := stack.pop(), stack.pop()
if y.Cmp(common.Big0) == 0 {
if y.Sign() == 0 {
stack.push(new(big.Int))
} else {
stack.push(math.U256(x.Mod(x, y)))
@ -105,11 +105,11 @@ func opMod(pc *uint64, evm *EVM, contract *Contract, memory *Memory, stack *Stac
func opSmod(pc *uint64, evm *EVM, contract *Contract, memory *Memory, stack *Stack) ([]byte, error) {
x, y := math.S256(stack.pop()), math.S256(stack.pop())
if y.Cmp(common.Big0) == 0 {
if y.Sign() == 0 {
stack.push(new(big.Int))
} else {
n := new(big.Int)
if x.Cmp(common.Big0) < 0 {
if x.Sign() < 0 {
n.SetInt64(-1)
} else {
n.SetInt64(1)
@ -221,7 +221,7 @@ func opEq(pc *uint64, evm *EVM, contract *Contract, memory *Memory, stack *Stack
func opIszero(pc *uint64, evm *EVM, contract *Contract, memory *Memory, stack *Stack) ([]byte, error) {
x := stack.pop()
if x.Cmp(common.Big0) > 0 {
if x.Sign() > 0 {
stack.push(new(big.Int))
} else {
stack.push(evm.interpreter.intPool.get().SetUint64(1))
@ -252,10 +252,11 @@ func opXor(pc *uint64, evm *EVM, contract *Contract, memory *Memory, stack *Stac
evm.interpreter.intPool.put(y)
return nil, nil
}
func opByte(pc *uint64, evm *EVM, contract *Contract, memory *Memory, stack *Stack) ([]byte, error) {
th, val := stack.pop(), stack.pop()
if th.Cmp(big.NewInt(32)) < 0 {
byte := evm.interpreter.intPool.get().SetInt64(int64(common.LeftPadBytes(val.Bytes(), 32)[th.Int64()]))
byte := evm.interpreter.intPool.get().SetInt64(int64(math.PaddedBigBytes(val, 32)[th.Int64()]))
stack.push(byte)
} else {
stack.push(new(big.Int))
@ -505,7 +506,7 @@ func opJump(pc *uint64, evm *EVM, contract *Contract, memory *Memory, stack *Sta
}
func opJumpi(pc *uint64, evm *EVM, contract *Contract, memory *Memory, stack *Stack) ([]byte, error) {
pos, cond := stack.pop(), stack.pop()
if cond.BitLen() > 0 {
if cond.Sign() != 0 {
if !contract.jumpdests.has(contract.CodeHash, contract.Code, pos) {
nop := contract.GetOp(pos.Uint64())
return nil, fmt.Errorf("invalid jump destination (%v) %v", nop, pos)
@ -583,7 +584,7 @@ func opCall(pc *uint64, evm *EVM, contract *Contract, memory *Memory, stack *Sta
// Get the arguments from the memory
args := memory.Get(inOffset.Int64(), inSize.Int64())
if value.BitLen() > 0 {
if value.Sign() != 0 {
gas += params.CallStipend
}
@ -616,7 +617,7 @@ func opCallCode(pc *uint64, evm *EVM, contract *Contract, memory *Memory, stack
// Get the arguments from the memory
args := memory.Get(inOffset.Int64(), inSize.Int64())
if value.BitLen() > 0 {
if value.Sign() != 0 {
gas += params.CallStipend
}

View File

@ -23,6 +23,7 @@ import (
"unicode"
"github.com/ethereum/go-ethereum/common"
"github.com/ethereum/go-ethereum/common/math"
)
type Storage map[common.Hash]common.Hash
@ -180,7 +181,7 @@ func StdErrFormat(logs []StructLog) {
fmt.Fprintln(os.Stderr, "STACK =", len(log.Stack))
for i := len(log.Stack) - 1; i >= 0; i-- {
fmt.Fprintf(os.Stderr, "%04d: %x\n", len(log.Stack)-i-1, common.LeftPadBytes(log.Stack[i].Bytes(), 32))
fmt.Fprintf(os.Stderr, "%04d: %x\n", len(log.Stack)-i-1, math.PaddedBigBytes(log.Stack[i], 32))
}
const maxMem = 10