consensus, core/*, params: metropolis preparation refactor

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)

consensus/ethash/consensus.go

@@ -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
 }

consensus/ethash/consensus_test.go

@@ -23,6 +23,7 @@ import (
 	"testing"
 
 	"github.com/ethereum/go-ethereum/common/math"
+	"github.com/ethereum/go-ethereum/core/types"
 	"github.com/ethereum/go-ethereum/params"
 )
 
@@ -71,7 +72,11 @@ func TestCalcDifficulty(t *testing.T) {
 	config := &params.ChainConfig{HomesteadBlock: big.NewInt(1150000)}
 	for name, test := range tests {
 		number := new(big.Int).Sub(test.CurrentBlocknumber, big.NewInt(1))
-		diff := CalcDifficulty(config, test.CurrentTimestamp, test.ParentTimestamp, number, test.ParentDifficulty)
+		diff := CalcDifficulty(config, test.CurrentTimestamp, &types.Header{
+			Number:     number,
+			Time:       test.ParentTimestamp,
+			Difficulty: test.ParentDifficulty,
+		})
 		if diff.Cmp(test.CurrentDifficulty) != 0 {
 			t.Error(name, "failed. Expected", test.CurrentDifficulty, "and calculated", diff)
 		}

core/chain_makers.go

@@ -84,7 +84,7 @@ func (b *BlockGen) AddTx(tx *types.Transaction) {
 	if b.gasPool == nil {
 		b.SetCoinbase(common.Address{})
 	}
-	b.statedb.StartRecord(tx.Hash(), common.Hash{}, len(b.txs))
+	b.statedb.Prepare(tx.Hash(), common.Hash{}, len(b.txs))
 	receipt, _, err := ApplyTransaction(b.config, nil, &b.header.Coinbase, b.gasPool, b.statedb, b.header, tx, b.header.GasUsed, vm.Config{})
 	if err != nil {
 		panic(err)
@@ -142,7 +142,7 @@ func (b *BlockGen) OffsetTime(seconds int64) {
 	if b.header.Time.Cmp(b.parent.Header().Time) <= 0 {
 		panic("block time out of range")
 	}
-	b.header.Difficulty = ethash.CalcDifficulty(b.config, b.header.Time.Uint64(), b.parent.Time().Uint64(), b.parent.Number(), b.parent.Difficulty())
+	b.header.Difficulty = ethash.CalcDifficulty(b.config, b.header.Time.Uint64(), b.parent.Header())
 }
 
 // GenerateChain creates a chain of n blocks. The first block's
@@ -209,15 +209,23 @@ func makeHeader(config *params.ChainConfig, parent *types.Block, state *state.St
 	} else {
 		time = new(big.Int).Add(parent.Time(), big.NewInt(10)) // block time is fixed at 10 seconds
 	}
+	parentHeader := parent.Header()
+	// adjust the parent time
+	parentHeader.Time = new(big.Int).Sub(time, big.NewInt(10))
+
 	return &types.Header{
 		Root:       state.IntermediateRoot(config.IsEIP158(parent.Number())),
 		ParentHash: parent.Hash(),
 		Coinbase:   parent.Coinbase(),
-		Difficulty: ethash.CalcDifficulty(config, time.Uint64(), new(big.Int).Sub(time, big.NewInt(10)).Uint64(), parent.Number(), parent.Difficulty()),
-		GasLimit:   CalcGasLimit(parent),
-		GasUsed:    new(big.Int),
-		Number:     new(big.Int).Add(parent.Number(), common.Big1),
-		Time:       time,
+		Difficulty: ethash.CalcDifficulty(config, time.Uint64(), &types.Header{
+			Number:     parent.Number(),
+			Time:       new(big.Int).Sub(time, big.NewInt(10)),
+			Difficulty: parent.Difficulty(),
+		}),
+		GasLimit: CalcGasLimit(parent),
+		GasUsed:  new(big.Int),
+		Number:   new(big.Int).Add(parent.Number(), common.Big1),
+		Time:     time,
 	}
 }
 

core/state/statedb.go

@@ -62,8 +62,9 @@ type StateDB struct {
 	codeSizeCache *lru.Cache
 
 	// This map holds 'live' objects, which will get modified while processing a state transition.
-	stateObjects      map[common.Address]*stateObject
-	stateObjectsDirty map[common.Address]struct{}
+	stateObjects           map[common.Address]*stateObject
+	stateObjectsDirty      map[common.Address]struct{}
+	stateObjectsDestructed map[common.Address]struct{}
 
 	// The refund counter, also used by state transitioning.
 	refund *big.Int
@@ -92,14 +93,15 @@ func New(root common.Hash, db ethdb.Database) (*StateDB, error) {
 	}
 	csc, _ := lru.New(codeSizeCacheSize)
 	return &StateDB{
-		db:                db,
-		trie:              tr,
-		codeSizeCache:     csc,
-		stateObjects:      make(map[common.Address]*stateObject),
-		stateObjectsDirty: make(map[common.Address]struct{}),
-		refund:            new(big.Int),
-		logs:              make(map[common.Hash][]*types.Log),
-		preimages:         make(map[common.Hash][]byte),
+		db:                     db,
+		trie:                   tr,
+		codeSizeCache:          csc,
+		stateObjects:           make(map[common.Address]*stateObject),
+		stateObjectsDirty:      make(map[common.Address]struct{}),
+		stateObjectsDestructed: make(map[common.Address]struct{}),
+		refund:                 new(big.Int),
+		logs:                   make(map[common.Hash][]*types.Log),
+		preimages:              make(map[common.Hash][]byte),
 	}, nil
 }
 
@@ -114,14 +116,15 @@ func (self *StateDB) New(root common.Hash) (*StateDB, error) {
 		return nil, err
 	}
 	return &StateDB{
-		db:                self.db,
-		trie:              tr,
-		codeSizeCache:     self.codeSizeCache,
-		stateObjects:      make(map[common.Address]*stateObject),
-		stateObjectsDirty: make(map[common.Address]struct{}),
-		refund:            new(big.Int),
-		logs:              make(map[common.Hash][]*types.Log),
-		preimages:         make(map[common.Hash][]byte),
+		db:                     self.db,
+		trie:                   tr,
+		codeSizeCache:          self.codeSizeCache,
+		stateObjects:           make(map[common.Address]*stateObject),
+		stateObjectsDirty:      make(map[common.Address]struct{}),
+		stateObjectsDestructed: make(map[common.Address]struct{}),
+		refund:                 new(big.Int),
+		logs:                   make(map[common.Hash][]*types.Log),
+		preimages:              make(map[common.Hash][]byte),
 	}, nil
 }
 
@@ -138,6 +141,7 @@ func (self *StateDB) Reset(root common.Hash) error {
 	self.trie = tr
 	self.stateObjects = make(map[common.Address]*stateObject)
 	self.stateObjectsDirty = make(map[common.Address]struct{})
+	self.stateObjectsDestructed = make(map[common.Address]struct{})
 	self.thash = common.Hash{}
 	self.bhash = common.Hash{}
 	self.txIndex = 0
@@ -173,12 +177,6 @@ func (self *StateDB) pushTrie(t *trie.SecureTrie) {
 	}
 }
 
-func (self *StateDB) StartRecord(thash, bhash common.Hash, ti int) {
-	self.thash = thash
-	self.bhash = bhash
-	self.txIndex = ti
-}
-
 func (self *StateDB) AddLog(log *types.Log) {
 	self.journal = append(self.journal, addLogChange{txhash: self.thash})
 
@@ -510,21 +508,25 @@ func (self *StateDB) Copy() *StateDB {
 
 	// Copy all the basic fields, initialize the memory ones
 	state := &StateDB{
-		db:                self.db,
-		trie:              self.trie,
-		pastTries:         self.pastTries,
-		codeSizeCache:     self.codeSizeCache,
-		stateObjects:      make(map[common.Address]*stateObject, len(self.stateObjectsDirty)),
-		stateObjectsDirty: make(map[common.Address]struct{}, len(self.stateObjectsDirty)),
-		refund:            new(big.Int).Set(self.refund),
-		logs:              make(map[common.Hash][]*types.Log, len(self.logs)),
-		logSize:           self.logSize,
-		preimages:         make(map[common.Hash][]byte),
+		db:                     self.db,
+		trie:                   self.trie,
+		pastTries:              self.pastTries,
+		codeSizeCache:          self.codeSizeCache,
+		stateObjects:           make(map[common.Address]*stateObject, len(self.stateObjectsDirty)),
+		stateObjectsDirty:      make(map[common.Address]struct{}, len(self.stateObjectsDirty)),
+		stateObjectsDestructed: make(map[common.Address]struct{}, len(self.stateObjectsDestructed)),
+		refund:                 new(big.Int).Set(self.refund),
+		logs:                   make(map[common.Hash][]*types.Log, len(self.logs)),
+		logSize:                self.logSize,
+		preimages:              make(map[common.Hash][]byte),
 	}
 	// Copy the dirty states, logs, and preimages
 	for addr := range self.stateObjectsDirty {
 		state.stateObjects[addr] = self.stateObjects[addr].deepCopy(state, state.MarkStateObjectDirty)
 		state.stateObjectsDirty[addr] = struct{}{}
+		if self.stateObjects[addr].suicided {
+			state.stateObjectsDestructed[addr] = struct{}{}
+		}
 	}
 	for hash, logs := range self.logs {
 		state.logs[hash] = make([]*types.Log, len(logs))
@@ -590,6 +592,27 @@ func (s *StateDB) IntermediateRoot(deleteEmptyObjects bool) common.Hash {
 	return s.trie.Hash()
 }
 
+// Prepare sets the current transaction hash and index and block hash which is
+// used when the EVM emits new state logs.
+func (self *StateDB) Prepare(thash, bhash common.Hash, ti int) {
+	self.thash = thash
+	self.bhash = bhash
+	self.txIndex = ti
+}
+
+// Finalise finalises the state by removing the self destructed objects
+// in the current stateObjectsDestructed buffer and clears the journal
+// as well as the refunds.
+//
+// Please note that Finalise is used by EIP#98 and is used instead of
+// IntermediateRoot.
+func (s *StateDB) Finalise() {
+	for addr := range s.stateObjectsDestructed {
+		s.deleteStateObject(s.stateObjects[addr])
+	}
+	s.clearJournalAndRefund()
+}
+
 // DeleteSuicides flags the suicided objects for deletion so that it
 // won't be referenced again when called / queried up on.
 //

core/state_processor.go

@@ -69,7 +69,7 @@ func (p *StateProcessor) Process(block *types.Block, statedb *state.StateDB, cfg
 	}
 	// Iterate over and process the individual transactions
 	for i, tx := range block.Transactions() {
-		statedb.StartRecord(tx.Hash(), block.Hash(), i)
+		statedb.Prepare(tx.Hash(), block.Hash(), i)
 		receipt, _, err := ApplyTransaction(p.config, p.bc, nil, gp, statedb, header, tx, totalUsedGas, cfg)
 		if err != nil {
 			return nil, nil, nil, err
@@ -107,7 +107,8 @@ func ApplyTransaction(config *params.ChainConfig, bc *BlockChain, author *common
 	usedGas.Add(usedGas, gas)
 	// Create a new receipt for the transaction, storing the intermediate root and gas used by the tx
 	// based on the eip phase, we're passing wether the root touch-delete accounts.
-	receipt := types.NewReceipt(statedb.IntermediateRoot(config.IsEIP158(header.Number)).Bytes(), usedGas)
+	root := statedb.IntermediateRoot(config.IsEIP158(header.Number))
+	receipt := types.NewReceipt(root.Bytes(), usedGas)
 	receipt.TxHash = tx.Hash()
 	receipt.GasUsed = new(big.Int).Set(gas)
 	// if the transaction created a contract, store the creation address in the receipt.

core/types/transaction_signing.go

@@ -27,7 +27,12 @@ import (
 	"github.com/ethereum/go-ethereum/params"
 )
 
-var ErrInvalidChainId = errors.New("invalid chaid id for signer")
+var (
+	ErrInvalidChainId = errors.New("invalid chaid id for signer")
+
+	errAbstractSigner     = errors.New("abstract signer")
+	abstractSignerAddress = common.HexToAddress("ffffffffffffffffffffffffffffffffffffff")
+)
 
 // sigCache is used to cache the derived sender and contains
 // the signer used to derive it.
@@ -103,6 +108,17 @@ type Signer interface {
 	Equal(Signer) bool
 }
 
+/*
+// WithSignature returns a new transaction with the given signature. This signature
+// needs to be in the [R || S || V] format where V is 0 or 1.
+func (s EIP86Signer) WithSignature(tx *Transaction, sig []byte) (*Transaction, error) {
+}
+
+// Hash returns the hash to be signed by the sender.
+// It does not uniquely identify the transaction.
+func (s EIP86Signer) Hash(tx *Transaction) common.Hash {}
+*/
+
 // EIP155Transaction implements TransactionInterface using the
 // EIP155 rules
 type EIP155Signer struct {