Implement Create2 opcode for Constantinople

Closes ethereum#1106

Author: cburgdorf

eth/utils/address.py

@@ -3,6 +3,11 @@
 from eth_hash.auto import keccak
 from eth_typing import Address
 
+from eth.utils.numeric import (
+    int_to_big_endian,
+)
+
+
 def force_bytes_to_address(value: bytes) -> Address:
     trimmed_value = value[-20:]
     padded_value = trimmed_value.rjust(20, b'\x00')
@@ -11,3 +16,11 @@ def force_bytes_to_address(value: bytes) -> Address:
 
 def generate_contract_address(address: Address, nonce: bytes) -> Address:
     return Address(keccak(rlp.encode([address, nonce]))[-20:])
+
+
+def generate_safe_contract_address(address: Address,
+                                   salt: int,
+                                   call_data: bytes) -> Address:
+    return force_bytes_to_address(
+        keccak(b'\xff' + address + int_to_big_endian(salt) + keccak(call_data))
+    )

eth/vm/forks/byzantium/opcodes.py

@@ -103,7 +103,6 @@ def inner(computation):
         mnemonic=mnemonics.CREATE,
         gas_cost=constants.GAS_CREATE,
     )(),
-    # TODO: CREATE2
     #
     # Storage
     #

eth/vm/forks/constantinople/opcodes.py

@@ -19,6 +19,7 @@
 from eth.vm.logic import (
     arithmetic,
     context,
+    system,
 )
 from eth.vm.opcode import (
     as_opcode
@@ -46,6 +47,11 @@
         mnemonic=mnemonics.EXTCODEHASH,
         gas_cost=GAS_EXTCODEHASH_EIP1052,
     ),
+    opcode_values.CREATE2: system.Create2.configure(
+        __name__='opcode:CREATE2',
+        mnemonic=mnemonics.CREATE2,
+        gas_cost=constants.GAS_CREATE,
+    )(),
 }
 
 CONSTANTINOPLE_OPCODES = merge(

eth/vm/logic/system.py

@@ -12,6 +12,7 @@
 from eth.utils.address import (
     force_bytes_to_address,
     generate_contract_address,
+    generate_safe_contract_address,
 )
 from eth.utils.hexadecimal import (
     encode_hex,
@@ -100,44 +101,72 @@ def _selfdestruct(computation: BaseComputation, beneficiary: Address) -> None:
     raise Halt('SELFDESTRUCT')
 
 
+class CreateOpcodeStackData:
+
+    def __init__(self,
+                 endowment: int,
+                 memory_start: int,
+                 memory_length: int,
+                 salt: int = None) -> None:
+
+        self.endowment = endowment
+        self.memory_start = memory_start
+        self.memory_length = memory_length
+        self.salt = salt
+
+
 class Create(Opcode):
 
     def max_child_gas_modifier(self, gas: int) -> int:
         return gas
 
-    def __call__(self, computation: BaseComputation) -> None:
-        computation.consume_gas(self.gas_cost, reason=self.mnemonic)
+    def generate_contract_address(self,
+                                  stack_data: CreateOpcodeStackData,
+                                  call_data: bytes,
+                                  computation: BaseComputation) -> Address:
 
-        value, start_position, size = computation.stack_pop(
+        creation_nonce = computation.state.account_db.get_nonce(computation.msg.storage_address)
+        computation.state.account_db.increment_nonce(computation.msg.storage_address)
+
+        contract_address = generate_contract_address(
+            computation.msg.storage_address,
+            creation_nonce,
+        )
+
+        return contract_address
+
+    def get_stack_data(self, computation: BaseComputation) -> CreateOpcodeStackData:
+        endowment, memory_start, memory_length = computation.stack_pop(
             num_items=3,
             type_hint=constants.UINT256,
         )
 
-        computation.extend_memory(start_position, size)
+        return CreateOpcodeStackData(endowment, memory_start, memory_length)
+
+    def __call__(self, computation: BaseComputation) -> None:
+        computation.consume_gas(self.gas_cost, reason=self.mnemonic)
+
+        stack_data = self.get_stack_data(computation)
+
+        computation.extend_memory(stack_data.memory_start, stack_data.memory_length)
 
         insufficient_funds = computation.state.account_db.get_balance(
             computation.msg.storage_address
-        ) < value
+        ) < stack_data.endowment
         stack_too_deep = computation.msg.depth + 1 > constants.STACK_DEPTH_LIMIT
 
         if insufficient_funds or stack_too_deep:
             computation.stack_push(0)
             return
 
-        call_data = computation.memory_read(start_position, size)
+        call_data = computation.memory_read(stack_data.memory_start, stack_data.memory_length)
 
         create_msg_gas = self.max_child_gas_modifier(
             computation.get_gas_remaining()
         )
-        computation.consume_gas(create_msg_gas, reason="CREATE")
+        computation.consume_gas(create_msg_gas, reason=self.mnemonic)
 
-        creation_nonce = computation.state.account_db.get_nonce(computation.msg.storage_address)
-        computation.state.account_db.increment_nonce(computation.msg.storage_address)
-
-        contract_address = generate_contract_address(
-            computation.msg.storage_address,
-            creation_nonce,
-        )
+        contract_address = self.generate_contract_address(stack_data, call_data, computation)
 
         is_collision = computation.state.account_db.account_has_code_or_nonce(contract_address)
 
@@ -152,7 +181,7 @@ def __call__(self, computation: BaseComputation) -> None:
         child_msg = computation.prepare_child_message(
             gas=create_msg_gas,
             to=constants.CREATE_CONTRACT_ADDRESS,
-            value=value,
+            value=stack_data.endowment,
             data=b'',
             code=call_data,
             create_address=contract_address,
@@ -177,3 +206,26 @@ def __call__(self, computation: BaseComputation) -> None:
         if computation.msg.is_static:
             raise WriteProtection("Cannot modify state while inside of a STATICCALL context")
         return super().__call__(computation)
+
+
+class Create2(CreateByzantium):
+
+    def get_stack_data(self, computation: BaseComputation) -> CreateOpcodeStackData:
+
+        endowment, memory_start, memory_length, salt = computation.stack_pop(
+            num_items=4,
+            type_hint=constants.UINT256,
+        )
+
+        return CreateOpcodeStackData(endowment, memory_start, memory_length, salt)
+
+    def generate_contract_address(self,
+                                  stack_data: CreateOpcodeStackData,
+                                  call_data: bytes,
+                                  computation: BaseComputation) -> Address:
+
+        return generate_safe_contract_address(
+            computation.msg.storage_address,
+            stack_data.salt,
+            call_data
+        )

eth/vm/mnemonics.py

@@ -163,6 +163,7 @@
 # System
 #
 CREATE = 'CREATE'
+CREATE2 = 'CREATE2'
 CALL = 'CALL'
 CALLCODE = 'CALLCODE'
 STATICCALL = 'STATICCALL'

eth/vm/opcode_values.py

@@ -183,6 +183,7 @@
 # System
 #
 CREATE = 0xf0
+CREATE2 = 0xf5
 CALL = 0xf1
 CALLCODE = 0xf2
 RETURN = 0xf3