core, core/vm: added gas price variance table

This implements 1b & 1c of EIP150 by adding a new GasTable which must be
returned from the RuleSet config method. This table is used to determine
the gas prices for the current epoch.

Please note that when the CreateBySuicide gas price is set it is assumed
that we're in the new epoch phase.

In addition this PR will serve as temporary basis while refactorisation
in being done in the EVM64 PR, which will substentially overhaul the gas
price code.

1 files changed, 66 insertions, 11 deletions

diff --git a/core/vm/vm.go b/core/vm/vm.go
index 033ada21c..fcffcf317 100644
--- a/core/vm/vm.go
+++ b/core/vm/vm.go
@@ -44,6 +44,7 @@ type EVM struct {
 	env       Environment
 	jumpTable vmJumpTable
 	cfg       Config
+	gasTable  params.GasTable
 }
 
 // New returns a new instance of the EVM.
@@ -52,6 +53,7 @@ func New(env Environment, cfg Config) *EVM {
 		env:       env,
 		jumpTable: newJumpTable(env.RuleSet(), env.BlockNumber()),
 		cfg:       cfg,
+		gasTable:  env.RuleSet().GasTable(env.BlockNumber()),
 	}
 }
 
@@ -169,7 +171,7 @@ func (evm *EVM) Run(contract *Contract, input []byte) (ret []byte, err error) {
 		// Get the memory location of pc
 		op = contract.GetOp(pc)
 		// calculate the new memory size and gas price for the current executing opcode
-		newMemSize, cost, err = calculateGasAndSize(evm.env, contract, caller, op, statedb, mem, stack)
+		newMemSize, cost, err = calculateGasAndSize(evm.gasTable, evm.env, contract, caller, op, statedb, mem, stack)
 		if err != nil {
 			return nil, err
 		}
@@ -234,7 +236,7 @@ func (evm *EVM) Run(contract *Contract, input []byte) (ret []byte, err error) {
 
 // calculateGasAndSize calculates the required given the opcode and stack items calculates the new memorysize for
 // the operation. This does not reduce gas or resizes the memory.
-func calculateGasAndSize(env Environment, contract *Contract, caller ContractRef, op OpCode, statedb Database, mem *Memory, stack *Stack) (*big.Int, *big.Int, error) {
+func calculateGasAndSize(gasTable params.GasTable, env Environment, contract *Contract, caller ContractRef, op OpCode, statedb Database, mem *Memory, stack *Stack) (*big.Int, *big.Int, error) {
 	var (
 		gas                 = new(big.Int)
 		newMemSize *big.Int = new(big.Int)
@@ -246,6 +248,24 @@ func calculateGasAndSize(env Environment, contract *Contract, caller ContractRef
 
 	// stack Check, memory resize & gas phase
 	switch op {
+	case SUICIDE:
+		// if suicide is not nil: homestead gas fork
+		if gasTable.CreateBySuicide != nil {
+			gas.Set(gasTable.Suicide)
+			if !env.Db().Exist(common.BigToAddress(stack.data[len(stack.data)-1])) {
+				gas.Add(gas, gasTable.CreateBySuicide)
+			}
+		}
+
+		if !statedb.HasSuicided(contract.Address()) {
+			statedb.AddRefund(params.SuicideRefundGas)
+		}
+	case EXTCODESIZE:
+		gas.Set(gasTable.ExtcodeSize)
+	case BALANCE:
+		gas.Set(gasTable.Balance)
+	case SLOAD:
+		gas.Set(gasTable.SLoad)
 	case SWAP1, SWAP2, SWAP3, SWAP4, SWAP5, SWAP6, SWAP7, SWAP8, SWAP9, SWAP10, SWAP11, SWAP12, SWAP13, SWAP14, SWAP15, SWAP16:
 		n := int(op - SWAP1 + 2)
 		err := stack.require(n)
@@ -274,6 +294,8 @@ func calculateGasAndSize(env Environment, contract *Contract, caller ContractRef
 		gas.Add(gas, new(big.Int).Mul(mSize, params.LogDataGas))
 
 		newMemSize = calcMemSize(mStart, mSize)
+
+		quadMemGas(mem, newMemSize, gas)
 	case EXP:
 		gas.Add(gas, new(big.Int).Mul(big.NewInt(int64(len(stack.data[stack.len()-2].Bytes()))), params.ExpByteGas))
 	case SSTORE:
@@ -302,67 +324,100 @@ func calculateGasAndSize(env Environment, contract *Contract, caller ContractRef
 			g = params.SstoreResetGas
 		}
 		gas.Set(g)
-	case SUICIDE:
-		if !statedb.HasSuicided(contract.Address()) {
-			statedb.AddRefund(params.SuicideRefundGas)
-		}
 	case MLOAD:
 		newMemSize = calcMemSize(stack.peek(), u256(32))
+		quadMemGas(mem, newMemSize, gas)
 	case MSTORE8:
 		newMemSize = calcMemSize(stack.peek(), u256(1))
+		quadMemGas(mem, newMemSize, gas)
 	case MSTORE:
 		newMemSize = calcMemSize(stack.peek(), u256(32))
+		quadMemGas(mem, newMemSize, gas)
 	case RETURN:
 		newMemSize = calcMemSize(stack.peek(), stack.data[stack.len()-2])
+		quadMemGas(mem, newMemSize, gas)
 	case SHA3:
 		newMemSize = calcMemSize(stack.peek(), stack.data[stack.len()-2])
 
 		words := toWordSize(stack.data[stack.len()-2])
 		gas.Add(gas, words.Mul(words, params.Sha3WordGas))
+
+		quadMemGas(mem, newMemSize, gas)
 	case CALLDATACOPY:
 		newMemSize = calcMemSize(stack.peek(), stack.data[stack.len()-3])
 
 		words := toWordSize(stack.data[stack.len()-3])
 		gas.Add(gas, words.Mul(words, params.CopyGas))
+
+		quadMemGas(mem, newMemSize, gas)
 	case CODECOPY:
 		newMemSize = calcMemSize(stack.peek(), stack.data[stack.len()-3])
 
 		words := toWordSize(stack.data[stack.len()-3])
 		gas.Add(gas, words.Mul(words, params.CopyGas))
+
+		quadMemGas(mem, newMemSize, gas)
 	case EXTCODECOPY:
+		gas.Set(gasTable.ExtcodeCopy)
+
 		newMemSize = calcMemSize(stack.data[stack.len()-2], stack.data[stack.len()-4])
 
 		words := toWordSize(stack.data[stack.len()-4])
 		gas.Add(gas, words.Mul(words, params.CopyGas))
 
+		quadMemGas(mem, newMemSize, gas)
 	case CREATE:
 		newMemSize = calcMemSize(stack.data[stack.len()-2], stack.data[stack.len()-3])
+
+		quadMemGas(mem, newMemSize, gas)
 	case CALL, CALLCODE:
-		gas.Add(gas, stack.data[stack.len()-1])
+		gas.Set(gasTable.Calls)
 
 		if op == CALL {
 			if !env.Db().Exist(common.BigToAddress(stack.data[stack.len()-2])) {
 				gas.Add(gas, params.CallNewAccountGas)
 			}
 		}
-
 		if len(stack.data[stack.len()-3].Bytes()) > 0 {
 			gas.Add(gas, params.CallValueTransferGas)
 		}
-
 		x := calcMemSize(stack.data[stack.len()-6], stack.data[stack.len()-7])
 		y := calcMemSize(stack.data[stack.len()-4], stack.data[stack.len()-5])
 
 		newMemSize = common.BigMax(x, y)
+
+		quadMemGas(mem, newMemSize, gas)
+
+		cg := callGas(gasTable, contract.Gas, gas, stack.data[stack.len()-1])
+		// Replace the stack item with the new gas calculation. This means that
+		// either the original item is left on the stack or the item is replaced by:
+		// (availableGas - gas) * 63 / 64
+		// We replace the stack item so that it's available when the opCall instruction is
+		// called. This information is otherwise lost due to the dependency on *current*
+		// available gas.
+		stack.data[stack.len()-1] = cg
+		gas.Add(gas, cg)
+
 	case DELEGATECALL:
-		gas.Add(gas, stack.data[stack.len()-1])
+		gas.Set(gasTable.Calls)
 
 		x := calcMemSize(stack.data[stack.len()-5], stack.data[stack.len()-6])
 		y := calcMemSize(stack.data[stack.len()-3], stack.data[stack.len()-4])
 
 		newMemSize = common.BigMax(x, y)
+
+		quadMemGas(mem, newMemSize, gas)
+
+		cg := callGas(gasTable, contract.Gas, gas, stack.data[stack.len()-1])
+		// Replace the stack item with the new gas calculation. This means that
+		// either the original item is left on the stack or the item is replaced by:
+		// (availableGas - gas) * 63 / 64
+		// We replace the stack item so that it's available when the opCall instruction is
+		// called.
+		stack.data[stack.len()-1] = cg
+		gas.Add(gas, cg)
+
 	}
-	quadMemGas(mem, newMemSize, gas)
 
 	return newMemSize, gas, nil
 }