params: core, core/vm, miner: 64bit gas instructions (#3514)

Reworked the EVM gas instructions to use 64bit integers rather than
arbitrary size big ints. All gas operations, be it additions,
multiplications or divisions, are checked and guarded against 64 bit
integer overflows.

In additon, most of the protocol paramaters in the params package have
been converted to uint64 and are now constants rather than variables.

* common/math: added overflow check ops
* core: vmenv, env renamed to evm
* eth, internal/ethapi, les: unmetered eth_call and cancel methods
* core/vm: implemented big.Int pool for evm instructions
* core/vm: unexported intPool methods & verification methods
* core/vm: added memoryGasCost overflow check and test

1 files changed, 299 insertions, 0 deletions

diff --git a/core/vm/evm.go b/core/vm/evm.go
new file mode 100644
index 000000000..0c5d998c2
--- /dev/null
+++ b/core/vm/evm.go
@@ -0,0 +1,299 @@
+// Copyright 2014 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 (
+	"math/big"
+	"sync/atomic"
+
+	"github.com/ethereum/go-ethereum/common"
+	"github.com/ethereum/go-ethereum/crypto"
+	"github.com/ethereum/go-ethereum/params"
+)
+
+type (
+	CanTransferFunc func(StateDB, common.Address, *big.Int) bool
+	TransferFunc    func(StateDB, common.Address, common.Address, *big.Int)
+	// GetHashFunc returns the nth block hash in the blockchain
+	// and is used by the BLOCKHASH EVM op code.
+	GetHashFunc func(uint64) common.Hash
+)
+
+// Context provides the EVM with auxiliary information. Once provided it shouldn't be modified.
+type Context struct {
+	// CanTransfer returns whether the account contains
+	// sufficient ether to transfer the value
+	CanTransfer CanTransferFunc
+	// Transfer transfers ether from one account to the other
+	Transfer TransferFunc
+	// GetHash returns the hash corresponding to n
+	GetHash GetHashFunc
+
+	// Message information
+	Origin   common.Address // Provides information for ORIGIN
+	GasPrice *big.Int       // Provides information for GASPRICE
+
+	// Block information
+	Coinbase    common.Address // Provides information for COINBASE
+	GasLimit    *big.Int       // Provides information for GASLIMIT
+	BlockNumber *big.Int       // Provides information for NUMBER
+	Time        *big.Int       // Provides information for TIME
+	Difficulty  *big.Int       // Provides information for DIFFICULTY
+}
+
+// EVM provides information about external sources for the EVM
+//
+// The EVM should never be reused and is not thread safe.
+type EVM struct {
+	// Context provides auxiliary blockchain related information
+	Context
+	// StateDB gives access to the underlying state
+	StateDB StateDB
+	// Depth is the current call stack
+	depth int
+
+	// chainConfig contains information about the current chain
+	chainConfig *params.ChainConfig
+	// virtual machine configuration options used to initialise the
+	// evm.
+	vmConfig Config
+	// global (to this context) ethereum virtual machine
+	// used throughout the execution of the tx.
+	interpreter *Interpreter
+	// abort is used to abort the EVM calling operations
+	// NOTE: must be set atomically
+	abort int32
+}
+
+// NewEVM retutrns a new EVM evmironment.
+func NewEVM(ctx Context, statedb StateDB, chainConfig *params.ChainConfig, vmConfig Config) *EVM {
+	evm := &EVM{
+		Context:     ctx,
+		StateDB:     statedb,
+		vmConfig:    vmConfig,
+		chainConfig: chainConfig,
+	}
+
+	evm.interpreter = NewInterpreter(evm, vmConfig)
+	return evm
+}
+
+// Cancel cancels any running EVM operation. This may be called concurrently and it's safe to be
+// called multiple times.
+func (evm *EVM) Cancel() {
+	atomic.StoreInt32(&evm.abort, 1)
+}
+
+// Call executes the contract associated with the addr with the given input as parameters. It also handles any
+// necessary value transfer required and takes the necessary steps to create accounts and reverses the state in
+// case of an execution error or failed value transfer.
+func (evm *EVM) Call(caller ContractRef, addr common.Address, input []byte, gas uint64, value *big.Int) (ret []byte, leftOverGas uint64, err error) {
+	if evm.vmConfig.NoRecursion && evm.depth > 0 {
+		return nil, gas, nil
+	}
+
+	// Depth check execution. Fail if we're trying to execute above the
+	// limit.
+	if evm.depth > int(params.CallCreateDepth) {
+		return nil, gas, ErrDepth
+	}
+	if !evm.Context.CanTransfer(evm.StateDB, caller.Address(), value) {
+		return nil, gas, ErrInsufficientBalance
+	}
+
+	var (
+		to       Account
+		snapshot = evm.StateDB.Snapshot()
+	)
+	if !evm.StateDB.Exist(addr) {
+		if PrecompiledContracts[addr] == nil && evm.ChainConfig().IsEIP158(evm.BlockNumber) && value.BitLen() == 0 {
+			return nil, gas, nil
+		}
+
+		to = evm.StateDB.CreateAccount(addr)
+	} else {
+		to = evm.StateDB.GetAccount(addr)
+	}
+	evm.Transfer(evm.StateDB, caller.Address(), to.Address(), value)
+
+	// initialise a new contract and set the code that is to be used by the
+	// E The contract is a scoped evmironment for this execution context
+	// only.
+	contract := NewContract(caller, to, value, gas)
+	contract.SetCallCode(&addr, evm.StateDB.GetCodeHash(addr), evm.StateDB.GetCode(addr))
+
+	ret, err = evm.interpreter.Run(contract, input)
+	// When an error was returned by the EVM or when setting the creation code
+	// above we revert to the snapshot and consume any gas remaining. Additionally
+	// when we're in homestead this also counts for code storage gas errors.
+	if err != nil {
+		contract.UseGas(contract.Gas)
+
+		evm.StateDB.RevertToSnapshot(snapshot)
+	}
+	return ret, contract.Gas, err
+}
+
+// CallCode executes the contract associated with the addr with the given input as parameters. It also handles any
+// necessary value transfer required and takes the necessary steps to create accounts and reverses the state in
+// case of an execution error or failed value transfer.
+//
+// CallCode differs from Call in the sense that it executes the given address' code with the caller as context.
+func (evm *EVM) CallCode(caller ContractRef, addr common.Address, input []byte, gas uint64, value *big.Int) (ret []byte, leftOverGas uint64, err error) {
+	if evm.vmConfig.NoRecursion && evm.depth > 0 {
+		return nil, gas, nil
+	}
+
+	// Depth check execution. Fail if we're trying to execute above the
+	// limit.
+	if evm.depth > int(params.CallCreateDepth) {
+		return nil, gas, ErrDepth
+	}
+	if !evm.CanTransfer(evm.StateDB, caller.Address(), value) {
+		return nil, gas, ErrInsufficientBalance
+	}
+
+	var (
+		snapshot = evm.StateDB.Snapshot()
+		to       = evm.StateDB.GetAccount(caller.Address())
+	)
+	// initialise a new contract and set the code that is to be used by the
+	// E The contract is a scoped evmironment for this execution context
+	// only.
+	contract := NewContract(caller, to, value, gas)
+	contract.SetCallCode(&addr, evm.StateDB.GetCodeHash(addr), evm.StateDB.GetCode(addr))
+
+	ret, err = evm.interpreter.Run(contract, input)
+	if err != nil {
+		contract.UseGas(contract.Gas)
+
+		evm.StateDB.RevertToSnapshot(snapshot)
+	}
+
+	return ret, contract.Gas, err
+}
+
+// DelegateCall executes the contract associated with the addr with the given input as parameters.
+// It reverses the state in case of an execution error.
+//
+// DelegateCall differs from CallCode in the sense that it executes the given address' code with the caller as context
+// and the caller is set to the caller of the caller.
+func (evm *EVM) DelegateCall(caller ContractRef, addr common.Address, input []byte, gas uint64) (ret []byte, leftOverGas uint64, err error) {
+	if evm.vmConfig.NoRecursion && evm.depth > 0 {
+		return nil, gas, nil
+	}
+
+	// Depth check execution. Fail if we're trying to execute above the
+	// limit.
+	if evm.depth > int(params.CallCreateDepth) {
+		return nil, gas, ErrDepth
+	}
+
+	var (
+		snapshot = evm.StateDB.Snapshot()
+		to       = evm.StateDB.GetAccount(caller.Address())
+	)
+
+	// Iinitialise a new contract and make initialise the delegate values
+	contract := NewContract(caller, to, caller.Value(), gas).AsDelegate()
+	contract.SetCallCode(&addr, evm.StateDB.GetCodeHash(addr), evm.StateDB.GetCode(addr))
+
+	ret, err = evm.interpreter.Run(contract, input)
+	if err != nil {
+		contract.UseGas(contract.Gas)
+
+		evm.StateDB.RevertToSnapshot(snapshot)
+	}
+
+	return ret, contract.Gas, err
+}
+
+// Create creates a new contract using code as deployment code.
+func (evm *EVM) Create(caller ContractRef, code []byte, gas uint64, value *big.Int) (ret []byte, contractAddr common.Address, leftOverGas uint64, err error) {
+	if evm.vmConfig.NoRecursion && evm.depth > 0 {
+		return nil, common.Address{}, gas, nil
+	}
+
+	// Depth check execution. Fail if we're trying to execute above the
+	// limit.
+	if evm.depth > int(params.CallCreateDepth) {
+		return nil, common.Address{}, gas, ErrDepth
+	}
+	if !evm.CanTransfer(evm.StateDB, caller.Address(), value) {
+		return nil, common.Address{}, gas, ErrInsufficientBalance
+	}
+
+	// Create a new account on the state
+	nonce := evm.StateDB.GetNonce(caller.Address())
+	evm.StateDB.SetNonce(caller.Address(), nonce+1)
+
+	snapshot := evm.StateDB.Snapshot()
+	contractAddr = crypto.CreateAddress(caller.Address(), nonce)
+	to := evm.StateDB.CreateAccount(contractAddr)
+	if evm.ChainConfig().IsEIP158(evm.BlockNumber) {
+		evm.StateDB.SetNonce(contractAddr, 1)
+	}
+	evm.Transfer(evm.StateDB, caller.Address(), to.Address(), value)
+
+	// initialise a new contract and set the code that is to be used by the
+	// E The contract is a scoped evmironment for this execution context
+	// only.
+	contract := NewContract(caller, to, value, gas)
+	contract.SetCallCode(&contractAddr, crypto.Keccak256Hash(code), code)
+
+	ret, err = evm.interpreter.Run(contract, nil)
+
+	// check whether the max code size has been exceeded
+	maxCodeSizeExceeded := len(ret) > params.MaxCodeSize
+	// if the contract creation ran successfully and no errors were returned
+	// calculate the gas required to store the code. If the code could not
+	// be stored due to not enough gas set an error and let it be handled
+	// by the error checking condition below.
+	if err == nil && !maxCodeSizeExceeded {
+		createDataGas := uint64(len(ret)) * params.CreateDataGas
+		if contract.UseGas(createDataGas) {
+			evm.StateDB.SetCode(contractAddr, ret)
+		} else {
+			err = ErrCodeStoreOutOfGas
+		}
+	}
+
+	// When an error was returned by the EVM or when setting the creation code
+	// above we revert to the snapshot and consume any gas remaining. Additionally
+	// when we're in homestead this also counts for code storage gas errors.
+	if maxCodeSizeExceeded ||
+		(err != nil && (evm.ChainConfig().IsHomestead(evm.BlockNumber) || err != ErrCodeStoreOutOfGas)) {
+		evm.StateDB.RevertToSnapshot(snapshot)
+
+		// Nothing should be returned when an error is thrown.
+		return nil, contractAddr, 0, err
+	}
+	// If the vm returned with an error the return value should be set to nil.
+	// This isn't consensus critical but merely to for behaviour reasons such as
+	// tests, RPC calls, etc.
+	if err != nil {
+		ret = nil
+	}
+
+	return ret, contractAddr, contract.Gas, err
+}
+
+// ChainConfig returns the evmironment's chain configuration
+func (evm *EVM) ChainConfig() *params.ChainConfig { return evm.chainConfig }
+
+// Interpreter returns the EVM interpreter
+func (evm *EVM) Interpreter() *Interpreter { return evm.interpreter }