Merge branch 'multi-coin'

1 files changed, 441 insertions, 0 deletions

diff --git a/core/vm/gas_table.go b/core/vm/gas_table.go
new file mode 100644
index 0000000..2adaf85
--- /dev/null
+++ b/core/vm/gas_table.go
@@ -0,0 +1,441 @@
+// Copyright 2017 The go-ethereum Authors
+// This file is part of the go-ethereum library.
+//
+// The go-ethereum library is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Lesser General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// The go-ethereum library 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 Lesser General Public License for more details.
+//
+// You should have received a copy of the GNU Lesser General Public License
+// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
+
+package vm
+
+import (
+	"errors"
+
+	"github.com/ava-labs/coreth/params"
+	"github.com/ava-labs/go-ethereum/common"
+	"github.com/ava-labs/go-ethereum/common/math"
+)
+
+// memoryGasCost calculates the quadratic gas for memory expansion. It does so
+// only for the memory region that is expanded, not the total memory.
+func memoryGasCost(mem *Memory, newMemSize uint64) (uint64, error) {
+	if newMemSize == 0 {
+		return 0, nil
+	}
+	// The maximum that will fit in a uint64 is max_word_count - 1. Anything above
+	// that will result in an overflow. Additionally, a newMemSize which results in
+	// a newMemSizeWords larger than 0xFFFFFFFF will cause the square operation to
+	// overflow. The constant 0x1FFFFFFFE0 is the highest number that can be used
+	// without overflowing the gas calculation.
+	if newMemSize > 0x1FFFFFFFE0 {
+		return 0, errGasUintOverflow
+	}
+	newMemSizeWords := toWordSize(newMemSize)
+	newMemSize = newMemSizeWords * 32
+
+	if newMemSize > uint64(mem.Len()) {
+		square := newMemSizeWords * newMemSizeWords
+		linCoef := newMemSizeWords * params.MemoryGas
+		quadCoef := square / params.QuadCoeffDiv
+		newTotalFee := linCoef + quadCoef
+
+		fee := newTotalFee - mem.lastGasCost
+		mem.lastGasCost = newTotalFee
+
+		return fee, nil
+	}
+	return 0, nil
+}
+
+// memoryCopierGas creates the gas functions for the following opcodes, and takes
+// the stack position of the operand which determines the size of the data to copy
+// as argument:
+// CALLDATACOPY (stack position 2)
+// CODECOPY (stack position 2)
+// EXTCODECOPY (stack poition 3)
+// RETURNDATACOPY (stack position 2)
+func memoryCopierGas(stackpos int) gasFunc {
+	return func(evm *EVM, contract *Contract, stack *Stack, mem *Memory, memorySize uint64) (uint64, error) {
+		// Gas for expanding the memory
+		gas, err := memoryGasCost(mem, memorySize)
+		if err != nil {
+			return 0, err
+		}
+		// And gas for copying data, charged per word at param.CopyGas
+		words, overflow := bigUint64(stack.Back(stackpos))
+		if overflow {
+			return 0, errGasUintOverflow
+		}
+
+		if words, overflow = math.SafeMul(toWordSize(words), params.CopyGas); overflow {
+			return 0, errGasUintOverflow
+		}
+
+		if gas, overflow = math.SafeAdd(gas, words); overflow {
+			return 0, errGasUintOverflow
+		}
+		return gas, nil
+	}
+}
+
+var (
+	gasCallDataCopy   = memoryCopierGas(2)
+	gasCodeCopy       = memoryCopierGas(2)
+	gasExtCodeCopy    = memoryCopierGas(3)
+	gasReturnDataCopy = memoryCopierGas(2)
+)
+
+func gasSStore(evm *EVM, contract *Contract, stack *Stack, mem *Memory, memorySize uint64) (uint64, error) {
+	var (
+		y, x    = stack.Back(1), stack.Back(0)
+		current = evm.StateDB.GetState(contract.Address(), common.BigToHash(x))
+	)
+	// The legacy gas metering only takes into consideration the current state
+	// Legacy rules should be applied if we are in Petersburg (removal of EIP-1283)
+	// OR Constantinople is not active
+	if evm.chainRules.IsPetersburg || !evm.chainRules.IsConstantinople {
+		// This checks for 3 scenario's and calculates gas accordingly:
+		//
+		// 1. From a zero-value address to a non-zero value         (NEW VALUE)
+		// 2. From a non-zero value address to a zero-value address (DELETE)
+		// 3. From a non-zero to a non-zero                         (CHANGE)
+		switch {
+		case current == (common.Hash{}) && y.Sign() != 0: // 0 => non 0
+			return params.SstoreSetGas, nil
+		case current != (common.Hash{}) && y.Sign() == 0: // non 0 => 0
+			evm.StateDB.AddRefund(params.SstoreRefundGas)
+			return params.SstoreClearGas, nil
+		default: // non 0 => non 0 (or 0 => 0)
+			return params.SstoreResetGas, nil
+		}
+	}
+	// The new gas metering is based on net gas costs (EIP-1283):
+	//
+	// 1. If current value equals new value (this is a no-op), 200 gas is deducted.
+	// 2. If current value does not equal new value
+	//   2.1. If original value equals current value (this storage slot has not been changed by the current execution context)
+	//     2.1.1. If original value is 0, 20000 gas is deducted.
+	// 	   2.1.2. Otherwise, 5000 gas is deducted. If new value is 0, add 15000 gas to refund counter.
+	// 	2.2. If original value does not equal current value (this storage slot is dirty), 200 gas is deducted. Apply both of the following clauses.
+	// 	  2.2.1. If original value is not 0
+	//       2.2.1.1. If current value is 0 (also means that new value is not 0), remove 15000 gas from refund counter. We can prove that refund counter will never go below 0.
+	//       2.2.1.2. If new value is 0 (also means that current value is not 0), add 15000 gas to refund counter.
+	// 	  2.2.2. If original value equals new value (this storage slot is reset)
+	//       2.2.2.1. If original value is 0, add 19800 gas to refund counter.
+	// 	     2.2.2.2. Otherwise, add 4800 gas to refund counter.
+	value := common.BigToHash(y)
+	if current == value { // noop (1)
+		return params.NetSstoreNoopGas, nil
+	}
+	original := evm.StateDB.GetCommittedState(contract.Address(), common.BigToHash(x))
+	if original == current {
+		if original == (common.Hash{}) { // create slot (2.1.1)
+			return params.NetSstoreInitGas, nil
+		}
+		if value == (common.Hash{}) { // delete slot (2.1.2b)
+			evm.StateDB.AddRefund(params.NetSstoreClearRefund)
+		}
+		return params.NetSstoreCleanGas, nil // write existing slot (2.1.2)
+	}
+	if original != (common.Hash{}) {
+		if current == (common.Hash{}) { // recreate slot (2.2.1.1)
+			evm.StateDB.SubRefund(params.NetSstoreClearRefund)
+		} else if value == (common.Hash{}) { // delete slot (2.2.1.2)
+			evm.StateDB.AddRefund(params.NetSstoreClearRefund)
+		}
+	}
+	if original == value {
+		if original == (common.Hash{}) { // reset to original inexistent slot (2.2.2.1)
+			evm.StateDB.AddRefund(params.NetSstoreResetClearRefund)
+		} else { // reset to original existing slot (2.2.2.2)
+			evm.StateDB.AddRefund(params.NetSstoreResetRefund)
+		}
+	}
+	return params.NetSstoreDirtyGas, nil
+}
+
+// 0. If *gasleft* is less than or equal to 2300, fail the current call.
+// 1. If current value equals new value (this is a no-op), SSTORE_NOOP_GAS gas is deducted.
+// 2. If current value does not equal new value:
+//   2.1. If original value equals current value (this storage slot has not been changed by the current execution context):
+//     2.1.1. If original value is 0, SSTORE_INIT_GAS gas is deducted.
+//     2.1.2. Otherwise, SSTORE_CLEAN_GAS gas is deducted. If new value is 0, add SSTORE_CLEAR_REFUND to refund counter.
+//   2.2. If original value does not equal current value (this storage slot is dirty), SSTORE_DIRTY_GAS gas is deducted. Apply both of the following clauses:
+//     2.2.1. If original value is not 0:
+//       2.2.1.1. If current value is 0 (also means that new value is not 0), subtract SSTORE_CLEAR_REFUND gas from refund counter. We can prove that refund counter will never go below 0.
+//       2.2.1.2. If new value is 0 (also means that current value is not 0), add SSTORE_CLEAR_REFUND gas to refund counter.
+//     2.2.2. If original value equals new value (this storage slot is reset):
+//       2.2.2.1. If original value is 0, add SSTORE_INIT_REFUND to refund counter.
+//       2.2.2.2. Otherwise, add SSTORE_CLEAN_REFUND gas to refund counter.
+func gasSStoreEIP2200(evm *EVM, contract *Contract, stack *Stack, mem *Memory, memorySize uint64) (uint64, error) {
+	// If we fail the minimum gas availability invariant, fail (0)
+	if contract.Gas <= params.SstoreSentryGasEIP2200 {
+		return 0, errors.New("not enough gas for reentrancy sentry")
+	}
+	// Gas sentry honoured, do the actual gas calculation based on the stored value
+	var (
+		y, x    = stack.Back(1), stack.Back(0)
+		current = evm.StateDB.GetState(contract.Address(), common.BigToHash(x))
+	)
+	value := common.BigToHash(y)
+
+	if current == value { // noop (1)
+		return params.SstoreNoopGasEIP2200, nil
+	}
+	original := evm.StateDB.GetCommittedState(contract.Address(), common.BigToHash(x))
+	if original == current {
+		if original == (common.Hash{}) { // create slot (2.1.1)
+			return params.SstoreInitGasEIP2200, nil
+		}
+		if value == (common.Hash{}) { // delete slot (2.1.2b)
+			evm.StateDB.AddRefund(params.SstoreClearRefundEIP2200)
+		}
+		return params.SstoreCleanGasEIP2200, nil // write existing slot (2.1.2)
+	}
+	if original != (common.Hash{}) {
+		if current == (common.Hash{}) { // recreate slot (2.2.1.1)
+			evm.StateDB.SubRefund(params.SstoreClearRefundEIP2200)
+		} else if value == (common.Hash{}) { // delete slot (2.2.1.2)
+			evm.StateDB.AddRefund(params.SstoreClearRefundEIP2200)
+		}
+	}
+	if original == value {
+		if original == (common.Hash{}) { // reset to original inexistent slot (2.2.2.1)
+			evm.StateDB.AddRefund(params.SstoreInitRefundEIP2200)
+		} else { // reset to original existing slot (2.2.2.2)
+			evm.StateDB.AddRefund(params.SstoreCleanRefundEIP2200)
+		}
+	}
+	return params.SstoreDirtyGasEIP2200, nil // dirty update (2.2)
+}
+
+func makeGasLog(n uint64) gasFunc {
+	return func(evm *EVM, contract *Contract, stack *Stack, mem *Memory, memorySize uint64) (uint64, error) {
+		requestedSize, overflow := bigUint64(stack.Back(1))
+		if overflow {
+			return 0, errGasUintOverflow
+		}
+
+		gas, err := memoryGasCost(mem, memorySize)
+		if err != nil {
+			return 0, err
+		}
+
+		if gas, overflow = math.SafeAdd(gas, params.LogGas); overflow {
+			return 0, errGasUintOverflow
+		}
+		if gas, overflow = math.SafeAdd(gas, n*params.LogTopicGas); overflow {
+			return 0, errGasUintOverflow
+		}
+
+		var memorySizeGas uint64
+		if memorySizeGas, overflow = math.SafeMul(requestedSize, params.LogDataGas); overflow {
+			return 0, errGasUintOverflow
+		}
+		if gas, overflow = math.SafeAdd(gas, memorySizeGas); overflow {
+			return 0, errGasUintOverflow
+		}
+		return gas, nil
+	}
+}
+
+func gasSha3(evm *EVM, contract *Contract, stack *Stack, mem *Memory, memorySize uint64) (uint64, error) {
+	gas, err := memoryGasCost(mem, memorySize)
+	if err != nil {
+		return 0, err
+	}
+	wordGas, overflow := bigUint64(stack.Back(1))
+	if overflow {
+		return 0, errGasUintOverflow
+	}
+	if wordGas, overflow = math.SafeMul(toWordSize(wordGas), params.Sha3WordGas); overflow {
+		return 0, errGasUintOverflow
+	}
+	if gas, overflow = math.SafeAdd(gas, wordGas); overflow {
+		return 0, errGasUintOverflow
+	}
+	return gas, nil
+}
+
+// pureMemoryGascost is used by several operations, which aside from their
+// static cost have a dynamic cost which is solely based on the memory
+// expansion
+func pureMemoryGascost(evm *EVM, contract *Contract, stack *Stack, mem *Memory, memorySize uint64) (uint64, error) {
+	return memoryGasCost(mem, memorySize)
+}
+
+var (
+	gasReturn  = pureMemoryGascost
+	gasRevert  = pureMemoryGascost
+	gasMLoad   = pureMemoryGascost
+	gasMStore8 = pureMemoryGascost
+	gasMStore  = pureMemoryGascost
+	gasCreate  = pureMemoryGascost
+)
+
+func gasCreate2(evm *EVM, contract *Contract, stack *Stack, mem *Memory, memorySize uint64) (uint64, error) {
+	gas, err := memoryGasCost(mem, memorySize)
+	if err != nil {
+		return 0, err
+	}
+	wordGas, overflow := bigUint64(stack.Back(2))
+	if overflow {
+		return 0, errGasUintOverflow
+	}
+	if wordGas, overflow = math.SafeMul(toWordSize(wordGas), params.Sha3WordGas); overflow {
+		return 0, errGasUintOverflow
+	}
+	if gas, overflow = math.SafeAdd(gas, wordGas); overflow {
+		return 0, errGasUintOverflow
+	}
+	return gas, nil
+}
+
+func gasExpFrontier(evm *EVM, contract *Contract, stack *Stack, mem *Memory, memorySize uint64) (uint64, error) {
+	expByteLen := uint64((stack.data[stack.len()-2].BitLen() + 7) / 8)
+
+	var (
+		gas      = expByteLen * params.ExpByteFrontier // no overflow check required. Max is 256 * ExpByte gas
+		overflow bool
+	)
+	if gas, overflow = math.SafeAdd(gas, params.ExpGas); overflow {
+		return 0, errGasUintOverflow
+	}
+	return gas, nil
+}
+
+func gasExpEIP158(evm *EVM, contract *Contract, stack *Stack, mem *Memory, memorySize uint64) (uint64, error) {
+	expByteLen := uint64((stack.data[stack.len()-2].BitLen() + 7) / 8)
+
+	var (
+		gas      = expByteLen * params.ExpByteEIP158 // no overflow check required. Max is 256 * ExpByte gas
+		overflow bool
+	)
+	if gas, overflow = math.SafeAdd(gas, params.ExpGas); overflow {
+		return 0, errGasUintOverflow
+	}
+	return gas, nil
+}
+
+func gasCall(evm *EVM, contract *Contract, stack *Stack, mem *Memory, memorySize uint64) (uint64, error) {
+	var (
+		gas            uint64
+		transfersValue = stack.Back(2).Sign() != 0
+		address        = common.BigToAddress(stack.Back(1))
+	)
+	if evm.chainRules.IsEIP158 {
+		if transfersValue && evm.StateDB.Empty(address) {
+			gas += params.CallNewAccountGas
+		}
+	} else if !evm.StateDB.Exist(address) {
+		gas += params.CallNewAccountGas
+	}
+	if transfersValue {
+		gas += params.CallValueTransferGas
+	}
+	memoryGas, err := memoryGasCost(mem, memorySize)
+	if err != nil {
+		return 0, err
+	}
+	var overflow bool
+	if gas, overflow = math.SafeAdd(gas, memoryGas); overflow {
+		return 0, errGasUintOverflow
+	}
+
+	evm.callGasTemp, err = callGas(evm.chainRules.IsEIP150, contract.Gas, gas, stack.Back(0))
+	if err != nil {
+		return 0, err
+	}
+	if gas, overflow = math.SafeAdd(gas, evm.callGasTemp); overflow {
+		return 0, errGasUintOverflow
+	}
+	return gas, nil
+}
+
+func gasCallCode(evm *EVM, contract *Contract, stack *Stack, mem *Memory, memorySize uint64) (uint64, error) {
+	memoryGas, err := memoryGasCost(mem, memorySize)
+	if err != nil {
+		return 0, err
+	}
+	var (
+		gas      uint64
+		overflow bool
+	)
+	if stack.Back(2).Sign() != 0 {
+		gas += params.CallValueTransferGas
+	}
+	if gas, overflow = math.SafeAdd(gas, memoryGas); overflow {
+		return 0, errGasUintOverflow
+	}
+	evm.callGasTemp, err = callGas(evm.chainRules.IsEIP150, contract.Gas, gas, stack.Back(0))
+	if err != nil {
+		return 0, err
+	}
+	if gas, overflow = math.SafeAdd(gas, evm.callGasTemp); overflow {
+		return 0, errGasUintOverflow
+	}
+	return gas, nil
+}
+
+func gasDelegateCall(evm *EVM, contract *Contract, stack *Stack, mem *Memory, memorySize uint64) (uint64, error) {
+	gas, err := memoryGasCost(mem, memorySize)
+	if err != nil {
+		return 0, err
+	}
+	evm.callGasTemp, err = callGas(evm.chainRules.IsEIP150, contract.Gas, gas, stack.Back(0))
+	if err != nil {
+		return 0, err
+	}
+	var overflow bool
+	if gas, overflow = math.SafeAdd(gas, evm.callGasTemp); overflow {
+		return 0, errGasUintOverflow
+	}
+	return gas, nil
+}
+
+func gasStaticCall(evm *EVM, contract *Contract, stack *Stack, mem *Memory, memorySize uint64) (uint64, error) {
+	gas, err := memoryGasCost(mem, memorySize)
+	if err != nil {
+		return 0, err
+	}
+	evm.callGasTemp, err = callGas(evm.chainRules.IsEIP150, contract.Gas, gas, stack.Back(0))
+	if err != nil {
+		return 0, err
+	}
+	var overflow bool
+	if gas, overflow = math.SafeAdd(gas, evm.callGasTemp); overflow {
+		return 0, errGasUintOverflow
+	}
+	return gas, nil
+}
+
+func gasSelfdestruct(evm *EVM, contract *Contract, stack *Stack, mem *Memory, memorySize uint64) (uint64, error) {
+	var gas uint64
+	// EIP150 homestead gas reprice fork:
+	if evm.chainRules.IsEIP150 {
+		gas = params.SelfdestructGasEIP150
+		var address = common.BigToAddress(stack.Back(0))
+
+		if evm.chainRules.IsEIP158 {
+			// if empty and transfers value
+			if evm.StateDB.Empty(address) && evm.StateDB.GetBalance(contract.Address()).Sign() != 0 {
+				gas += params.CreateBySelfdestructGas
+			}
+		} else if !evm.StateDB.Exist(address) {
+			gas += params.CreateBySelfdestructGas
+		}
+	}
+
+	if !evm.StateDB.HasSuicided(contract.Address()) {
+		evm.StateDB.AddRefund(params.SelfdestructRefundGas)
+	}
+	return gas, nil
+}