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consensus, core/*, params: metropolis preparation refactor

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This commit is a preparation for the upcoming metropolis hardfork. It
prepares the state, core and vm packages such that integration with
metropolis becomes less of a hassle.

* Difficulty calculation requires header instead of individual
  parameters
* statedb.StartRecord renamed to statedb.Prepare and added Finalise
  method required by metropolis, which removes unwanted accounts from
  the state (i.e. selfdestruct)
* State keeps record of destructed objects (in addition to dirty
  objects)
* core/vm pre-compiles may now return errors
* core/vm pre-compiles gas check now take the full byte slice as argument
  instead of just the size
* core/vm now keeps several hard-fork instruction tables instead of a
  single instruction table and removes the need for hard-fork checks in
  the instructions
* core/vm contains a empty restruction function which is added in
  preparation of metropolis write-only mode operations
* Adds the bn256 curve
* Adds and sets the metropolis chain config block parameters (2^64-1)
This commit is contained in:
Jeffrey Wilcke
2017-02-01 22:36:51 +01:00
parent a2f23ca9b1
commit 10a57fc3d4
28 changed files with 2865 additions and 183 deletions
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46
consensus/ethash/consensus.go
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@ -239,7 +239,7 @@ func (ethash *Ethash) verifyHeader(chain consensus.ChainReader, header, parent *
return errZeroBlockTime
}
// Verify the block's difficulty based in it's timestamp and parent's difficulty
expected := CalcDifficulty(chain.Config(), header.Time.Uint64(), parent.Time.Uint64(), parent.Number, parent.Difficulty)
expected := CalcDifficulty(chain.Config(), header.Time.Uint64(), parent)
if expected.Cmp(header.Difficulty) != 0 {
return fmt.Errorf("invalid difficulty: have %v, want %v", header.Difficulty, expected)
}
@ -283,16 +283,19 @@ func (ethash *Ethash) verifyHeader(chain consensus.ChainReader, header, parent *
return nil
}
// CalcDifficulty is the difficulty adjustment algorithm. It returns the difficulty
// that a new block should have when created at time given the parent block's time
// and difficulty.
// CalcDifficulty is the difficulty adjustment algorithm. It returns
// the difficulty that a new block should have when created at time
// given the parent block's time and difficulty.
//
// TODO (karalabe): Move the chain maker into this package and make this private!
func CalcDifficulty(config *params.ChainConfig, time, parentTime uint64, parentNumber, parentDiff *big.Int) *big.Int {
if config.IsHomestead(new(big.Int).Add(parentNumber, common.Big1)) {
return calcDifficultyHomestead(time, parentTime, parentNumber, parentDiff)
func CalcDifficulty(config *params.ChainConfig, time uint64, parent *types.Header) *big.Int {
next := new(big.Int).Add(parent.Number, common.Big1)
switch {
case config.IsHomestead(next):
return calcDifficultyHomestead(time, parent)
default:
return calcDifficultyFrontier(time, parent)
}
return calcDifficultyFrontier(time, parentTime, parentNumber, parentDiff)
}
// Some weird constants to avoid constant memory allocs for them.
@ -305,15 +308,15 @@ var (
// calcDifficultyHomestead is the difficulty adjustment algorithm. It returns
// the difficulty that a new block should have when created at time given the
// parent block's time and difficulty. The calculation uses the Homestead rules.
func calcDifficultyHomestead(time, parentTime uint64, parentNumber, parentDiff *big.Int) *big.Int {
func calcDifficultyHomestead(time uint64, parent *types.Header) *big.Int {
// https://github.com/ethereum/EIPs/blob/master/EIPS/eip-2.mediawiki
// algorithm:
// diff = (parent_diff +
// (parent_diff / 2048 * max(1 - (block_timestamp - parent_timestamp) // 10, -99))
// ) + 2^(periodCount - 2)
bigTime := new(big.Int).SetUint64(time)
bigParentTime := new(big.Int).SetUint64(parentTime)
bigTime := new(big.Int).Set(parent.Time)
bigParentTime := new(big.Int).Set(parent.Time)
// holds intermediate values to make the algo easier to read & audit
x := new(big.Int)
@ -329,16 +332,16 @@ func calcDifficultyHomestead(time, parentTime uint64, parentNumber, parentDiff *
x.Set(bigMinus99)
}
// (parent_diff + parent_diff // 2048 * max(1 - (block_timestamp - parent_timestamp) // 10, -99))
y.Div(parentDiff, params.DifficultyBoundDivisor)
y.Div(parent.Difficulty, params.DifficultyBoundDivisor)
x.Mul(y, x)
x.Add(parentDiff, x)
x.Add(parent.Difficulty, x)
// minimum difficulty can ever be (before exponential factor)
if x.Cmp(params.MinimumDifficulty) < 0 {
x.Set(params.MinimumDifficulty)
}
// for the exponential factor
periodCount := new(big.Int).Add(parentNumber, common.Big1)
periodCount := new(big.Int).Add(parent.Number, common.Big1)
periodCount.Div(periodCount, expDiffPeriod)
// the exponential factor, commonly referred to as "the bomb"
@ -354,25 +357,25 @@ func calcDifficultyHomestead(time, parentTime uint64, parentNumber, parentDiff *
// calcDifficultyFrontier is the difficulty adjustment algorithm. It returns the
// difficulty that a new block should have when created at time given the parent
// block's time and difficulty. The calculation uses the Frontier rules.
func calcDifficultyFrontier(time, parentTime uint64, parentNumber, parentDiff *big.Int) *big.Int {
func calcDifficultyFrontier(time uint64, parent *types.Header) *big.Int {
diff := new(big.Int)
adjust := new(big.Int).Div(parentDiff, params.DifficultyBoundDivisor)
adjust := new(big.Int).Div(parent.Difficulty, params.DifficultyBoundDivisor)
bigTime := new(big.Int)
bigParentTime := new(big.Int)
bigTime.SetUint64(time)
bigParentTime.SetUint64(parentTime)
bigParentTime.Set(parent.Time)
if bigTime.Sub(bigTime, bigParentTime).Cmp(params.DurationLimit) < 0 {
diff.Add(parentDiff, adjust)
diff.Add(parent.Difficulty, adjust)
} else {
diff.Sub(parentDiff, adjust)
diff.Sub(parent.Difficulty, adjust)
}
if diff.Cmp(params.MinimumDifficulty) < 0 {
diff.Set(params.MinimumDifficulty)
}
periodCount := new(big.Int).Add(parentNumber, common.Big1)
periodCount := new(big.Int).Add(parent.Number, common.Big1)
periodCount.Div(periodCount, expDiffPeriod)
if periodCount.Cmp(common.Big1) > 0 {
// diff = diff + 2^(periodCount - 2)
@ -434,8 +437,7 @@ func (ethash *Ethash) Prepare(chain consensus.ChainReader, header *types.Header)
if parent == nil {
return consensus.ErrUnknownAncestor
}
header.Difficulty = CalcDifficulty(chain.Config(), header.Time.Uint64(),
parent.Time.Uint64(), parent.Number, parent.Difficulty)
header.Difficulty = CalcDifficulty(chain.Config(), header.Time.Uint64(), parent)
return nil
}