ethereum.forks.paris.vm.interpreterethereum.forks.shanghai.vm.interpreter

Ethereum Virtual Machine (EVM) Interpreter.

.. contents:: Table of Contents :backlinks: none :local:

Introduction

A straightforward interpreter that executes EVM code.

STACK_DEPTH_LIMIT

62
STACK_DEPTH_LIMIT = Uint(1024)

MAX_CODE_SIZE

63
MAX_CODE_SIZE = 0x6000

MAX_INIT_CODE_SIZE

64
MAX_INIT_CODE_SIZE = 2 * MAX_CODE_SIZE

MessageCallOutput

Output of a particular message call.

Contains the following:

  1. `gas_left`: remaining gas after execution.
  2. `refund_counter`: gas to refund after execution.
  3. `logs`: list of `Log` generated during execution.
  4. `accounts_to_delete`: Contracts which have self-destructed.
  5. `error`: The error from the execution if any.
67
@dataclass
class MessageCallOutput:

gas_left

81
    gas_left: Uint

refund_counter

82
    refund_counter: U256

logs

83
    logs: Tuple[Log, ...]

accounts_to_delete

84
    accounts_to_delete: Set[Address]

error

85
    error: Optional[EthereumException]

process_message_call

If message.target is empty then it creates a smart contract else it executes a call from the message.caller to the message.target.

Parameters

message : Transaction specific items.

Returns

output : MessageCallOutput Output of the message call

def process_message_call(message: Message) -> MessageCallOutput:
89
    """
90
    If `message.target` is empty then it creates a smart contract
91
    else it executes a call from the `message.caller` to the `message.target`.
92
93
    Parameters
94
    ----------
95
    message :
96
        Transaction specific items.
97
98
    Returns
99
    -------
100
    output : `MessageCallOutput`
101
        Output of the message call
102
103
    """
104
    block_env = message.block_env
105
    refund_counter = U256(0)
106
    if message.target == Bytes0(b""):
107
        is_collision = account_has_code_or_nonce(
108
            block_env.state, message.current_target
109
        ) or account_has_storage(block_env.state, message.current_target)
110
        if is_collision:
111
            return MessageCallOutput(
112
                Uint(0), U256(0), tuple(), set(), AddressCollision()
113
            )
114
        else:
115
            evm = process_create_message(message)
116
    else:
117
        evm = process_message(message)
118
119
    if evm.error:
120
        logs: Tuple[Log, ...] = ()
121
        accounts_to_delete = set()
122
    else:
123
        logs = evm.logs
124
        accounts_to_delete = evm.accounts_to_delete
125
        refund_counter += U256(evm.refund_counter)
126
127
    tx_end = TransactionEnd(
128
        int(message.gas) - int(evm.gas_left), evm.output, evm.error
129
    )
130
    evm_trace(evm, tx_end)
131
132
    return MessageCallOutput(
133
        gas_left=evm.gas_left,
134
        refund_counter=refund_counter,
135
        logs=logs,
136
        accounts_to_delete=accounts_to_delete,
137
        error=evm.error,
138
    )

process_create_message

Executes a call to create a smart contract.

Parameters

message : Transaction specific items.

Returns

evm: :py:class:~ethereum.forks.paris.vm.Evm~ethereum.forks.shanghai.vm.Evm Items containing execution specific objects.

def process_create_message(message: Message) -> Evm:
142
    """
143
    Executes a call to create a smart contract.
144
145
    Parameters
146
    ----------
147
    message :
148
        Transaction specific items.
149
150
    Returns
151
    -------
151
    evm: :py:class:`~ethereum.forks.paris.vm.Evm`
152
    evm: :py:class:`~ethereum.forks.shanghai.vm.Evm`
153
        Items containing execution specific objects.
154
155
    """
156
    state = message.block_env.state
157
    # take snapshot of state before processing the message
158
    begin_transaction(state)
159
160
    # If the address where the account is being created has storage, it is
161
    # destroyed. This can only happen in the following highly unlikely
162
    # circumstances:
163
    # * The address created by a `CREATE` call collides with a subsequent
164
    #   `CREATE` or `CREATE2` call.
165
    # * The first `CREATE` happened before Spurious Dragon and left empty
166
    #   code.
167
    destroy_storage(state, message.current_target)
168
169
    # In the previously mentioned edge case the preexisting storage is ignored
170
    # for gas refund purposes. In order to do this we must track created
171
    # accounts.
172
    mark_account_created(state, message.current_target)
173
174
    increment_nonce(state, message.current_target)
175
    evm = process_message(message)
176
    if not evm.error:
177
        contract_code = evm.output
178
        contract_code_gas = Uint(len(contract_code)) * GAS_CODE_DEPOSIT
179
        try:
180
            if len(contract_code) > 0:
181
                if contract_code[0] == 0xEF:
182
                    raise InvalidContractPrefix
183
            charge_gas(evm, contract_code_gas)
184
            if len(contract_code) > MAX_CODE_SIZE:
185
                raise OutOfGasError
186
        except ExceptionalHalt as error:
187
            rollback_transaction(state)
188
            evm.gas_left = Uint(0)
189
            evm.output = b""
190
            evm.error = error
191
        else:
192
            set_code(state, message.current_target, contract_code)
193
            commit_transaction(state)
194
    else:
195
        rollback_transaction(state)
196
    return evm

process_message

Move ether and execute the relevant code.

Parameters

message : Transaction specific items.

Returns

evm: :py:class:~ethereum.forks.paris.vm.Evm~ethereum.forks.shanghai.vm.Evm Items containing execution specific objects

def process_message(message: Message) -> Evm:
200
    """
201
    Move ether and execute the relevant code.
202
203
    Parameters
204
    ----------
205
    message :
206
        Transaction specific items.
207
208
    Returns
209
    -------
209
    evm: :py:class:`~ethereum.forks.paris.vm.Evm`
210
    evm: :py:class:`~ethereum.forks.shanghai.vm.Evm`
211
        Items containing execution specific objects
212
213
    """
214
    state = message.block_env.state
215
    if message.depth > STACK_DEPTH_LIMIT:
216
        raise StackDepthLimitError("Stack depth limit reached")
217
218
    code = message.code
219
    valid_jump_destinations = get_valid_jump_destinations(code)
220
    evm = Evm(
221
        pc=Uint(0),
222
        stack=[],
223
        memory=bytearray(),
224
        code=code,
225
        gas_left=message.gas,
226
        valid_jump_destinations=valid_jump_destinations,
227
        logs=(),
228
        refund_counter=0,
229
        running=True,
230
        message=message,
231
        output=b"",
232
        accounts_to_delete=set(),
233
        return_data=b"",
234
        error=None,
235
        accessed_addresses=message.accessed_addresses,
236
        accessed_storage_keys=message.accessed_storage_keys,
237
    )
238
239
    # take snapshot of state before processing the message
240
    begin_transaction(state)
241
242
    if message.should_transfer_value and message.value != 0:
243
        move_ether(
244
            state, message.caller, message.current_target, message.value
245
        )
246
247
    try:
248
        if evm.message.code_address in PRE_COMPILED_CONTRACTS:
249
            evm_trace(evm, PrecompileStart(evm.message.code_address))
250
            PRE_COMPILED_CONTRACTS[evm.message.code_address](evm)
251
            evm_trace(evm, PrecompileEnd())
252
        else:
253
            while evm.running and evm.pc < ulen(evm.code):
254
                try:
255
                    op = Ops(evm.code[evm.pc])
256
                except ValueError as e:
257
                    raise InvalidOpcode(evm.code[evm.pc]) from e
258
259
                evm_trace(evm, OpStart(op))
260
                op_implementation[op](evm)
261
                evm_trace(evm, OpEnd())
262
263
            evm_trace(evm, EvmStop(Ops.STOP))
264
265
    except ExceptionalHalt as error:
266
        evm_trace(evm, OpException(error))
267
        evm.gas_left = Uint(0)
268
        evm.output = b""
269
        evm.error = error
270
    except Revert as error:
271
        evm_trace(evm, OpException(error))
272
        evm.error = error
273
274
    if evm.error:
275
        # revert state to the last saved checkpoint
276
        # since the message call resulted in an error
277
        rollback_transaction(state)
278
    else:
279
        commit_transaction(state)
280
    return evm