core, core/vm, crypto: fixes for homestead

* Removed some strange code that didn't apply state reverting properly
* Refactored code setting from vm & state transition to the executioner
* Updated tests

9 files changed, 123 insertions, 74 deletions

diff --git a/core/vm/contract.go b/core/vm/contract.go
index dac81a529..d23995218 100644
--- a/core/vm/contract.go
+++ b/core/vm/contract.go
@@ -26,7 +26,6 @@ import (
 type ContractRef interface {
 	ReturnGas(*big.Int, *big.Int)
 	Address() common.Address
-	SetAddress(common.Address)
 	Value() *big.Int
 	SetCode([]byte)
 	EachStorage(cb func(key, value []byte))
@@ -35,8 +34,12 @@ type ContractRef interface {
 // Contract represents an ethereum contract in the state database. It contains
 // the the contract code, calling arguments. Contract implements ContractRef
 type Contract struct {
-	caller ContractRef
-	self   ContractRef
+	// CallerAddress is the result of the caller which initialised this
+	// contract. However when the "call method" is delegated this value
+	// needs to be initialised to that of the caller's caller.
+	CallerAddress common.Address
+	caller        ContractRef
+	self          ContractRef
 
 	jumpdests destinations // result of JUMPDEST analysis.
 
@@ -51,9 +54,9 @@ type Contract struct {
 	DelegateCall bool
 }
 
-// Create a new context for the given data items.
+// NewContract returns a new contract environment for the execution of EVM.
 func NewContract(caller ContractRef, object ContractRef, value, gas, price *big.Int) *Contract {
-	c := &Contract{caller: caller, self: object, Args: nil}
+	c := &Contract{CallerAddress: caller.Address(), caller: caller, self: object, Args: nil}
 
 	if parent, ok := caller.(*Contract); ok {
 		// Reuse JUMPDEST analysis from parent context if available.
@@ -74,6 +77,16 @@ func NewContract(caller ContractRef, object ContractRef, value, gas, price *big.
 	return c
 }
 
+// AsDelegate sets the contract to be a delegate call and returns the current
+// contract (for chaining calls)
+func (c *Contract) AsDelegate() *Contract {
+	c.DelegateCall = true
+	// NOTE: caller must, at all times be a contract. It should never happen
+	// that caller is something other than a Contract.
+	c.CallerAddress = c.caller.(*Contract).CallerAddress
+	return c
+}
+
 // GetOp returns the n'th element in the contract's byte array
 func (c *Contract) GetOp(n uint64) OpCode {
 	return OpCode(c.GetByte(n))
@@ -88,13 +101,19 @@ func (c *Contract) GetByte(n uint64) byte {
 	return 0
 }
 
-// Return returns the given ret argument and returns any remaining gas to the
-// caller
-func (c *Contract) Return(ret []byte) []byte {
+// Caller returns the caller of the contract.
+//
+// Caller will recursively call caller when the contract is a delegate
+// call, including that of caller's caller.
+func (c *Contract) Caller() common.Address {
+	return c.CallerAddress
+}
+
+// Finalise finalises the contract and returning any remaining gas to the original
+// caller.
+func (c *Contract) Finalise() {
 	// Return the remaining gas to the caller
 	c.caller.ReturnGas(c.Gas, c.Price)
-
-	return ret
 }
 
 // UseGas attempts the use gas and subtracts it and returns true on success
@@ -118,11 +137,6 @@ func (c *Contract) Address() common.Address {
 	return c.self.Address()
 }
 
-// SetAddress sets the contracts address
-func (c *Contract) SetAddress(addr common.Address) {
-	c.self.SetAddress(addr)
-}
-
 // Value returns the contracts value (sent to it from it's caller)
 func (c *Contract) Value() *big.Int {
 	return c.value
diff --git a/core/vm/environment.go b/core/vm/environment.go
index dc60af2ca..a58e3ba2b 100644
--- a/core/vm/environment.go
+++ b/core/vm/environment.go
@@ -121,7 +121,6 @@ type Account interface {
 	SetNonce(uint64)
 	Balance() *big.Int
 	Address() common.Address
-	SetAddress(common.Address)
 	ReturnGas(*big.Int, *big.Int)
 	SetCode([]byte)
 	EachStorage(cb func(key, value []byte))
diff --git a/core/vm/instructions.go b/core/vm/instructions.go
index 9d3d4e6fe..26f7671ff 100644
--- a/core/vm/instructions.go
+++ b/core/vm/instructions.go
@@ -337,13 +337,7 @@ func opOrigin(instr instruction, pc *uint64, env Environment, contract *Contract
 }
 
 func opCaller(instr instruction, pc *uint64, env Environment, contract *Contract, memory *Memory, stack *stack) {
-	var bigAddr *big.Int
-	if contract.DelegateCall {
-		bigAddr = env.Origin().Big()
-	} else {
-		bigAddr = contract.caller.Address().Big()
-	}
-	stack.push(bigAddr)
+	stack.push(contract.Caller().Big())
 }
 
 func opCallValue(instr instruction, pc *uint64, env Environment, contract *Contract, memory *Memory, stack *stack) {
@@ -514,6 +508,25 @@ func opGas(instr instruction, pc *uint64, env Environment, contract *Contract, m
 }
 
 func opCreate(instr instruction, pc *uint64, env Environment, contract *Contract, memory *Memory, stack *stack) {
+	var (
+		value        = stack.pop()
+		offset, size = stack.pop(), stack.pop()
+		input        = memory.Get(offset.Int64(), size.Int64())
+		gas          = new(big.Int).Set(contract.Gas)
+	)
+	contract.UseGas(contract.Gas)
+	_, addr, suberr := env.Create(contract, input, gas, contract.Price, value)
+	// Push item on the stack based on the returned error. If the ruleset is
+	// homestead we must check for CodeStoreOutOfGasError (homestead only
+	// rule) and treat as an error, if the ruleset is frontier we must
+	// ignore this error and pretend the operation was successful.
+	if params.IsHomestead(env.BlockNumber()) && suberr == CodeStoreOutOfGasError {
+		stack.push(new(big.Int))
+	} else if suberr != nil && suberr != CodeStoreOutOfGasError {
+		stack.push(new(big.Int))
+	} else {
+		stack.push(addr.Big())
+	}
 }
 
 func opCall(instr instruction, pc *uint64, env Environment, contract *Contract, memory *Memory, stack *stack) {
diff --git a/core/vm/jit.go b/core/vm/jit.go
index 1aa7d7ef2..504aab523 100644
--- a/core/vm/jit.go
+++ b/core/vm/jit.go
@@ -275,6 +275,11 @@ func CompileProgram(program *Program) (err error) {
 			program.addInstr(op, pc, opGas, nil)
 		case CREATE:
 			program.addInstr(op, pc, opCreate, nil)
+		case DELEGATECALL:
+			// Instruction added regardless of homestead phase.
+			// Homestead (and execution of the opcode) is checked during
+			// runtime.
+			program.addInstr(op, pc, opDelegateCall, nil)
 		case CALL:
 			program.addInstr(op, pc, opCall, nil)
 		case CALLCODE:
@@ -317,10 +322,14 @@ func runProgram(program *Program, pcstart uint64, mem *Memory, stack *stack, env
 		}()
 	}
 
+	homestead := params.IsHomestead(env.BlockNumber())
 	for pc < uint64(len(program.instructions)) {
 		instrCount++
 
 		instr := program.instructions[pc]
+		if instr.Op() == DELEGATECALL && !homestead {
+			return nil, fmt.Errorf("Invalid opcode 0x%x", instr.Op())
+		}
 
 		ret, err := instr.do(program, &pc, env, contract, mem, stack)
 		if err != nil {
@@ -328,13 +337,13 @@ func runProgram(program *Program, pcstart uint64, mem *Memory, stack *stack, env
 		}
 
 		if instr.halts() {
-			return contract.Return(ret), nil
+			return ret, nil
 		}
 	}
 
 	contract.Input = nil
 
-	return contract.Return(nil), nil
+	return nil, nil
 }
 
 // validDest checks if the given distination is a valid one given the
@@ -457,7 +466,6 @@ func jitCalculateGasAndSize(env Environment, contract *Contract, instr instructi
 		gas.Add(gas, stack.data[stack.len()-1])
 
 		if op == CALL {
-			//if env.Db().GetStateObject(common.BigToAddress(stack.data[stack.len()-2])) == nil {
 			if !env.Db().Exist(common.BigToAddress(stack.data[stack.len()-2])) {
 				gas.Add(gas, params.CallNewAccountGas)
 			}
@@ -471,6 +479,13 @@ func jitCalculateGasAndSize(env Environment, contract *Contract, instr instructi
 		y := calcMemSize(stack.data[stack.len()-4], stack.data[stack.len()-5])
 
 		newMemSize = common.BigMax(x, y)
+	case DELEGATECALL:
+		gas.Add(gas, stack.data[stack.len()-1])
+
+		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)
 
diff --git a/core/vm/jit_test.go b/core/vm/jit_test.go
index 8c50ed0f5..e8e078a46 100644
--- a/core/vm/jit_test.go
+++ b/core/vm/jit_test.go
@@ -127,6 +127,8 @@ type account struct{}
 
 func (account) SubBalance(amount *big.Int)             {}
 func (account) AddBalance(amount *big.Int)             {}
+func (account) SetAddress(common.Address)              {}
+func (account) Value() *big.Int                        { return nil }
 func (account) SetBalance(*big.Int)                    {}
 func (account) SetNonce(uint64)                        {}
 func (account) Balance() *big.Int                      { return nil }
@@ -206,3 +208,6 @@ func (self *Env) CallCode(caller ContractRef, addr common.Address, data []byte,
 func (self *Env) Create(caller ContractRef, data []byte, gas, price, value *big.Int) ([]byte, common.Address, error) {
 	return nil, common.Address{}, nil
 }
+func (self *Env) DelegateCall(me ContractRef, addr common.Address, data []byte, gas, price *big.Int) ([]byte, error) {
+	return nil, nil
+}
diff --git a/core/vm/jump_table.go b/core/vm/jump_table.go
index 222c93854..37d7bb160 100644
--- a/core/vm/jump_table.go
+++ b/core/vm/jump_table.go
@@ -1,13 +1,29 @@
 package vm
 
-import "math/big"
+import (
+	"math/big"
+
+	"github.com/ethereum/go-ethereum/params"
+)
 
 type jumpPtr struct {
 	fn    instrFn
 	valid bool
 }
 
-var jumpTable [256]jumpPtr
+type vmJumpTable [256]jumpPtr
+
+func (jt vmJumpTable) init(blockNumber *big.Int) {
+	// when initialising a new VM execution we must first check the homestead
+	// changes.
+	if params.IsHomestead(blockNumber) {
+		jumpTable[DELEGATECALL] = jumpPtr{opDelegateCall, true}
+	} else {
+		jumpTable[DELEGATECALL] = jumpPtr{nil, false}
+	}
+}
+
+var jumpTable vmJumpTable
 
 func init() {
 	jumpTable[ADD] = jumpPtr{opAdd, true}
@@ -62,10 +78,9 @@ func init() {
 	jumpTable[PC] = jumpPtr{nil, true}
 	jumpTable[MSIZE] = jumpPtr{opMsize, true}
 	jumpTable[GAS] = jumpPtr{opGas, true}
-	jumpTable[CREATE] = jumpPtr{nil, true}
+	jumpTable[CREATE] = jumpPtr{opCreate, true}
 	jumpTable[CALL] = jumpPtr{opCall, true}
 	jumpTable[CALLCODE] = jumpPtr{opCallCode, true}
-	jumpTable[DELEGATECALL] = jumpPtr{opDelegateCall, true}
 	jumpTable[LOG0] = jumpPtr{makeLog(0), true}
 	jumpTable[LOG1] = jumpPtr{makeLog(1), true}
 	jumpTable[LOG2] = jumpPtr{makeLog(2), true}
diff --git a/core/vm/jump_table_test.go b/core/vm/jump_table_test.go
new file mode 100644
index 000000000..98d34bef2
--- /dev/null
+++ b/core/vm/jump_table_test.go
@@ -0,0 +1,24 @@
+package vm
+
+import (
+	"math/big"
+	"testing"
+
+	"github.com/ethereum/go-ethereum/params"
+)
+
+func TestInit(t *testing.T) {
+	params.HomesteadBlock = big.NewInt(1)
+
+	jumpTable.init(big.NewInt(0))
+	if jumpTable[DELEGATECALL].valid {
+		t.Error("Expected DELEGATECALL not to be present")
+	}
+
+	for _, n := range []int64{1, 2, 100} {
+		jumpTable.init(big.NewInt(n))
+		if !jumpTable[DELEGATECALL].valid {
+			t.Error("Expected DELEGATECALL to be present for block", n)
+		}
+	}
+}
diff --git a/core/vm/opcodes.go b/core/vm/opcodes.go
index 00593ae95..7d861f1de 100644
--- a/core/vm/opcodes.go
+++ b/core/vm/opcodes.go
@@ -404,6 +404,7 @@ var stringToOp = map[string]OpCode{
 	"CALLDATALOAD": CALLDATALOAD,
 	"CALLDATASIZE": CALLDATASIZE,
 	"CALLDATACOPY": CALLDATACOPY,
+	"DELEGATECALL": DELEGATECALL,
 	"CODESIZE":     CODESIZE,
 	"CODECOPY":     CODECOPY,
 	"GASPRICE":     GASPRICE,
diff --git a/core/vm/vm.go b/core/vm/vm.go
index 863b2cc0d..320135ff2 100644
--- a/core/vm/vm.go
+++ b/core/vm/vm.go
@@ -35,6 +35,9 @@ type Vm struct {
 
 // New returns a new Vm
 func New(env Environment) *Vm {
+	// init the jump table. Also prepares the homestead changes
+	jumpTable.init(env.BlockNumber())
+
 	return &Vm{env: env}
 }
 
@@ -43,16 +46,6 @@ func (self *Vm) Run(contract *Contract, input []byte) (ret []byte, err error) {
 	self.env.SetDepth(self.env.Depth() + 1)
 	defer self.env.SetDepth(self.env.Depth() - 1)
 
-	// User defer pattern to check for an error and, based on the error being nil or not, use all gas and return.
-	defer func() {
-		if err != nil {
-			// In case of a VM exception (known exceptions) all gas consumed (panics NOT included).
-			contract.UseGas(contract.Gas)
-
-			ret = contract.Return(nil)
-		}
-	}()
-
 	if contract.CodeAddr != nil {
 		if p := Precompiled[contract.CodeAddr.Str()]; p != nil {
 			return self.RunPrecompiled(p, input, contract)
@@ -61,7 +54,7 @@ func (self *Vm) Run(contract *Contract, input []byte) (ret []byte, err error) {
 
 	// Don't bother with the execution if there's no code.
 	if len(contract.Code) == 0 {
-		return contract.Return(nil), nil
+		return nil, nil
 	}
 
 	var (
@@ -199,46 +192,17 @@ func (self *Vm) Run(contract *Contract, input []byte) (ret []byte, err error) {
 
 						continue
 					}
-				case CREATE:
-					var (
-						value        = stack.pop()
-						offset, size = stack.pop(), stack.pop()
-						input        = mem.Get(offset.Int64(), size.Int64())
-						gas          = new(big.Int).Set(contract.Gas)
-						addr         common.Address
-						ret          []byte
-						suberr       error
-					)
-					contract.UseGas(contract.Gas)
-					ret, addr, suberr = self.env.Create(contract, input, gas, contract.Price, value)
-					if suberr != nil {
-						stack.push(new(big.Int))
-					} else {
-						// gas < len(ret) * Createinstr.dataGas == NO_CODE
-						dataGas := big.NewInt(int64(len(ret)))
-						dataGas.Mul(dataGas, params.CreateDataGas)
-						if contract.UseGas(dataGas) {
-							self.env.Db().SetCode(addr, ret)
-						} else {
-							if params.IsHomestead(self.env.BlockNumber()) {
-								stack.push(new(big.Int))
-								return nil, CodeStoreOutOfGasError
-							}
-						}
-						stack.push(addr.Big())
-					}
-
 				case RETURN:
 					offset, size := stack.pop(), stack.pop()
 					ret := mem.GetPtr(offset.Int64(), size.Int64())
 
-					return contract.Return(ret), nil
+					return ret, nil
 				case SUICIDE:
 					opSuicide(instruction{}, nil, self.env, contract, mem, stack)
 
 					fallthrough
 				case STOP: // Stop the contract
-					return contract.Return(nil), nil
+					return nil, nil
 				}
 			}
 		} else {
@@ -359,7 +323,6 @@ func calculateGasAndSize(env Environment, contract *Contract, caller ContractRef
 		gas.Add(gas, stack.data[stack.len()-1])
 
 		if op == CALL {
-			//if env.Db().GetStateObject(common.BigToAddress(stack.data[stack.len()-2])) == nil {
 			if !env.Db().Exist(common.BigToAddress(stack.data[stack.len()-2])) {
 				gas.Add(gas, params.CallNewAccountGas)
 			}
@@ -392,7 +355,7 @@ func (self *Vm) RunPrecompiled(p *PrecompiledAccount, input []byte, contract *Co
 	if contract.UseGas(gas) {
 		ret = p.Call(input)
 
-		return contract.Return(ret), nil
+		return ret, nil
 	} else {
 		return nil, OutOfGasError
 	}