implement extcodehash (#420)

* implement extcodehash

* update dialyzer ignore file

.dialyzer.ignore-warnings

@@ -39,21 +39,21 @@
 
 # evm warnings
 
-apps/evm/lib/evm/functions.ex:181: Function 'not_enough_gas?'/2 has no local return
-apps/evm/lib/evm/functions.ex:193: Function 'is_invalid_jump_destination?'/3 will never be called
-apps/evm/lib/evm/functions.ex:203: Function 'static_state_modification?'/2 will never be called
-apps/evm/lib/evm/gas.ex:137: Function cost/2 has no local return
-apps/evm/lib/evm/gas.ex:137: Function cost/3 has no local return
-apps/evm/lib/evm/gas.ex:142: The call 'Elixir.EVM.Gas':operation_cost(atom(),_inputs@1::[integer()],_machine_state@1::#{'__struct__':='Elixir.EVM.MachineState', 'active_words':=integer(), 'gas':=integer(), 'last_return_data':=binary(), 'memory':=binary(), 'previously_active_words':=integer(), 'program_counter':=integer(), 'stack':=[integer()]},_exec_env@1::#{'__struct__':='Elixir.EVM.ExecEnv', 'account_interface':=atom(), 'address':=<<_:160>>, 'block_interface':=atom(), 'config':=atom(), 'data':=binary(), 'gas_price':=integer(), 'machine_code':=binary(), 'originator':=<<_:160>>, 'sender':=<<_:160>>, 'stack_depth':=integer(), 'static':=boolean(), 'value_in_wei':=integer()}) breaks the contract (atom(),['Elixir.EVM':val()],['Elixir.EVM':val()],'Elixir.EVM.MachineState':t()) -> t() | 'nil'
-apps/evm/lib/evm/gas.ex:303: Function operation_cost/0 has no local return
-apps/evm/lib/evm/gas.ex:303: The call 'Elixir.EVM.Gas':operation_cost('nil','nil','nil','nil') breaks the contract (atom(),['Elixir.EVM':val()],['Elixir.EVM':val()],'Elixir.EVM.MachineState':t()) -> t() | 'nil'
-apps/evm/lib/evm/gas.ex:303: Function operation_cost/1 has no local return
-apps/evm/lib/evm/gas.ex:303: The call 'Elixir.EVM.Gas':operation_cost(__@1::any(),'nil','nil','nil') breaks the contract (atom(),['Elixir.EVM':val()],['Elixir.EVM':val()],'Elixir.EVM.MachineState':t()) -> t() | 'nil'
-apps/evm/lib/evm/gas.ex:303: Function operation_cost/2 has no local return
-apps/evm/lib/evm/gas.ex:303: The call 'Elixir.EVM.Gas':operation_cost(__@1::any(),__@2::any(),'nil','nil') breaks the contract (atom(),['Elixir.EVM':val()],['Elixir.EVM':val()],'Elixir.EVM.MachineState':t()) -> t() | 'nil'
-apps/evm/lib/evm/gas.ex:303: Function operation_cost/3 has no local return
-apps/evm/lib/evm/gas.ex:303: The call 'Elixir.EVM.Gas':operation_cost(__@1::any(),__@2::any(),__@3::any(),'nil') breaks the contract (atom(),['Elixir.EVM':val()],['Elixir.EVM':val()],'Elixir.EVM.MachineState':t()) -> t() | 'nil'
-apps/evm/lib/evm/gas.ex:562: Function gas_cost_for_nested_operation/2 will never be called
+apps/evm/lib/evm/functions.ex:184: Function 'not_enough_gas?'/2 has no local return
+apps/evm/lib/evm/functions.ex:196: Function 'is_invalid_jump_destination?'/3 will never be called
+apps/evm/lib/evm/functions.ex:206: Function 'static_state_modification?'/2 will never be called
+apps/evm/lib/evm/gas.ex:138: Function cost/2 has no local return
+apps/evm/lib/evm/gas.ex:138: Function cost/3 has no local return
+apps/evm/lib/evm/gas.ex:143: The call 'Elixir.EVM.Gas':operation_cost(atom(),_inputs@1::[integer()],_machine_state@1::#{'__struct__':='Elixir.EVM.MachineState', 'active_words':=integer(), 'gas':=integer(), 'last_return_data':=binary(), 'memory':=binary(), 'previously_active_words':=integer(), 'program_counter':=integer(), 'stack':=[integer()]},_exec_env@1::#{'__struct__':='Elixir.EVM.ExecEnv', 'account_interface':=atom(), 'address':=<<_:160>>, 'block_interface':=atom(), 'config':=atom(), 'data':=binary(), 'gas_price':=integer(), 'machine_code':=binary(), 'originator':=<<_:160>>, 'sender':=<<_:160>>, 'stack_depth':=integer(), 'static':=boolean(), 'value_in_wei':=integer()}) breaks the contract (atom(),['Elixir.EVM':val()],['Elixir.EVM':val()],'Elixir.EVM.MachineState':t()) -> t() | 'nil'
+apps/evm/lib/evm/gas.ex:304: Function operation_cost/0 has no local return
+apps/evm/lib/evm/gas.ex:304: The call 'Elixir.EVM.Gas':operation_cost('nil','nil','nil','nil') breaks the contract (atom(),['Elixir.EVM':val()],['Elixir.EVM':val()],'Elixir.EVM.MachineState':t()) -> t() | 'nil'
+apps/evm/lib/evm/gas.ex:304: Function operation_cost/1 has no local return
+apps/evm/lib/evm/gas.ex:304: The call 'Elixir.EVM.Gas':operation_cost(__@1::any(),'nil','nil','nil') breaks the contract (atom(),['Elixir.EVM':val()],['Elixir.EVM':val()],'Elixir.EVM.MachineState':t()) -> t() | 'nil'
+apps/evm/lib/evm/gas.ex:304: Function operation_cost/2 has no local return
+apps/evm/lib/evm/gas.ex:304: The call 'Elixir.EVM.Gas':operation_cost(__@1::any(),__@2::any(),'nil','nil') breaks the contract (atom(),['Elixir.EVM':val()],['Elixir.EVM':val()],'Elixir.EVM.MachineState':t()) -> t() | 'nil'
+apps/evm/lib/evm/gas.ex:304: Function operation_cost/3 has no local return
+apps/evm/lib/evm/gas.ex:304: The call 'Elixir.EVM.Gas':operation_cost(__@1::any(),__@2::any(),__@3::any(),'nil') breaks the contract (atom(),['Elixir.EVM':val()],['Elixir.EVM':val()],'Elixir.EVM.MachineState':t()) -> t() | 'nil'
+apps/evm/lib/evm/gas.ex:566: Function gas_cost_for_nested_operation/2 will never be called
 apps/evm/lib/evm/machine_state.ex:53: Function subtract_gas/2 has no local return
 apps/evm/lib/evm/operation/environmental_information.ex:114: Function calldataload/2 has no local return
 apps/evm/lib/evm/operation/environmental_information.ex:117: The call 'Elixir.EVM.Helpers':decode_signed(binary()) breaks the contract (integer() | 'nil') -> 'Elixir.EVM':val() | 'nil'

apps/blockchain/lib/blockchain/interface/account_interface.ex

@@ -111,6 +111,13 @@ defimpl EVM.Interface.AccountInterface, for: Blockchain.Interface.AccountInterfa
     end
   end
 
+  @spec get_account_code_hash(AccountInterface.t(), EVM.address()) :: binary() | nil
+  def get_account_code_hash(account_interface, address) do
+    account = Account.get_account(account_interface.state, address)
+
+    unless is_nil(account), do: account.code_hash
+  end
+
   @doc """
   Given an account interface and an address, increments the nonce on the account,
   returning both a new `AccountInterface` and the previous nonce value.

apps/evm/lib/evm/configuration.ex

@@ -100,4 +100,8 @@ defprotocol EVM.Configuration do
   # EIP145
   @spec has_shift_operations?(t) :: boolean()
   def has_shift_operations?(t)
+
+  # EIP1052
+  @spec has_extcodehash?(t) :: boolean()
+  def has_extcodehash?(t)
 end

apps/evm/lib/evm/configuration/byzantium.ex

@@ -97,4 +97,7 @@ defimpl EVM.Configuration, for: EVM.Configuration.Byzantium do
   @spec has_shift_operations?(Configuration.t()) :: boolean()
   def has_shift_operations?(config),
     do: Configuration.has_shift_operations?(config.fallback_config)
+
+  @spec has_extcodehash?(Configuration.t()) :: boolean()
+  def has_extcodehash?(config), do: Configuration.has_extcodehash?(config.fallback_config)
 end

apps/evm/lib/evm/configuration/constantinople.ex

@@ -1,6 +1,7 @@
 defmodule EVM.Configuration.Constantinople do
   defstruct fallback_config: EVM.Configuration.Byzantium.new(),
-            has_shift_operations: true
+            has_shift_operations: true,
+            has_extcodehash: true
 
   def new do
     %__MODULE__{}
@@ -92,4 +93,7 @@ defimpl EVM.Configuration, for: EVM.Configuration.Constantinople do
   @spec has_shift_operations?(Configuration.t()) :: boolean()
   def has_shift_operations?(config),
     do: config.has_shift_operations
+
+  @spec has_extcodehash?(Configuration.t()) :: boolean()
+  def has_extcodehash?(config), do: config.has_extcodehash
 end

apps/evm/lib/evm/configuration/eip150.ex

@@ -100,4 +100,7 @@ defimpl EVM.Configuration, for: EVM.Configuration.EIP150 do
   @spec has_shift_operations?(Configuration.t()) :: boolean()
   def has_shift_operations?(config),
     do: Configuration.has_shift_operations?(config.fallback_config)
+
+  @spec has_extcodehash?(Configuration.t()) :: boolean()
+  def has_extcodehash?(config), do: Configuration.has_extcodehash?(config.fallback_config)
 end

apps/evm/lib/evm/configuration/eip158.ex

@@ -92,4 +92,7 @@ defimpl EVM.Configuration, for: EVM.Configuration.EIP158 do
   @spec has_shift_operations?(Configuration.t()) :: boolean()
   def has_shift_operations?(config),
     do: Configuration.has_shift_operations?(config.fallback_config)
+
+  @spec has_extcodehash?(Configuration.t()) :: boolean()
+  def has_extcodehash?(config), do: Configuration.has_extcodehash?(config.fallback_config)
 end

apps/evm/lib/evm/configuration/frontier.ex

@@ -22,7 +22,8 @@ defmodule EVM.Configuration.Frontier do
             has_ec_add_builtin: false,
             has_ec_mult_builtin: false,
             has_ec_pairing_builtin: false,
-            has_shift_operations: false
+            has_shift_operations: false,
+            has_extcodehash: false
 
   def new do
     %__MODULE__{}
@@ -104,4 +105,7 @@ defimpl EVM.Configuration, for: EVM.Configuration.Frontier do
 
   @spec has_shift_operations?(Configuration.t()) :: boolean()
   def has_shift_operations?(config), do: config.has_shift_operations
+
+  @spec has_extcodehash?(Configuration.t()) :: boolean()
+  def has_extcodehash?(config), do: config.has_extcodehash
 end

apps/evm/lib/evm/configuration/homestead.ex

@@ -93,4 +93,7 @@ defimpl EVM.Configuration, for: EVM.Configuration.Homestead do
   @spec has_shift_operations?(Configuration.t()) :: boolean()
   def has_shift_operations?(config),
     do: Configuration.has_shift_operations?(config.fallback_config)
+
+  @spec has_extcodehash?(Configuration.t()) :: boolean()
+  def has_extcodehash?(config), do: Configuration.has_extcodehash?(config.fallback_config)
 end

apps/evm/lib/evm/functions.ex

@@ -171,6 +171,9 @@ defmodule EVM.Functions do
         :sar ->
           if Configuration.has_shift_operations?(config), do: operation_metadata
 
+        :extcodehash ->
+          if Configuration.has_extcodehash?(config), do: operation_metadata
+
         _ ->
           operation_metadata
       end

apps/evm/lib/evm/gas.ex

@@ -70,6 +70,7 @@ defmodule EVM.Gas do
   @g_copy 3
   # Payment for BLOCKHASH operation
   @g_blockhash 20
+  @g_extcodehash 400
 
   @w_zero_instr [:stop, :return, :revert]
   @w_base_instr [
@@ -485,6 +486,9 @@ defmodule EVM.Gas do
       operation == :jumpdest ->
         @g_jumpdest
 
+      operation == :extcodehash ->
+        @g_extcodehash
+
       true ->
         0
     end

apps/evm/lib/evm/interface/account_interface.ex

@@ -28,6 +28,9 @@ defprotocol EVM.Interface.AccountInterface do
   @spec get_account_nonce(EVM.Interface.AccountInterface.t(), EVM.address()) :: integer()
   def get_account_nonce(mock_account_interface, address)
 
+  @spec get_account_code_hash(t, EVM.address()) :: binary() | nil
+  def get_account_code_hash(t, address)
+
   @spec increment_account_nonce(t, EVM.address()) :: {t(), integer()}
   def increment_account_nonce(t, address)
 

apps/evm/lib/evm/interface/mock/mock_account_interface.ex

@@ -78,6 +78,13 @@ defimpl EVM.Interface.AccountInterface, for: EVM.Interface.Mock.MockAccountInter
     end
   end
 
+  @spec get_account_code_hash(EVM.Interface.AccountInterface.t(), EVM.address()) :: binary() | nil
+  def get_account_code_hash(mock_account_interface, address) do
+    account = get_account(mock_account_interface, address)
+
+    unless is_nil(account), do: account.code_hash
+  end
+
   defp get_account(mock_account_interface, address) do
     Map.get(mock_account_interface.account_map, address)
   end

apps/evm/lib/evm/operation/environmental_information.ex

@@ -297,6 +297,18 @@ defmodule EVM.Operation.EnvironmentalInformation do
     end
   end
 
+  @spec extcodehash(Operation.stack_args(), Operation.vm_map()) :: Operation.op_result()
+  def extcodehash([address], %{exec_env: exec_env}) do
+    wrapped_address = Helpers.wrap_address(address)
+    hash = AccountInterface.get_account_code_hash(exec_env.account_interface, wrapped_address)
+
+    if is_nil(hash) do
+      0
+    else
+      hash
+    end
+  end
+
   @doc """
   Get size of output data from the previous call from the current environment.
 

apps/evm/lib/evm/operation/metadata/environmental_information.ex

@@ -121,6 +121,14 @@ defmodule EVM.Operation.Metadata.EnvironmentalInformation do
                       input_count: 3,
                       output_count: 0,
                       group: :environmental_information
+                    },
+                    %{
+                      id: 0x3F,
+                      description: "Returns the keccak256 hash of a contract’s code",
+                      sym: :extcodehash,
+                      input_count: 1,
+                      output_count: 1,
+                      group: :environmental_information
                     }
                   ],
                   do: struct(EVM.Operation.Metadata, operation)