ethereum.byzantium.vm

Ethereum Virtual Machine (EVM) ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

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

Introduction

The abstract computer which runs the code stored in an .fork_types.Account.

__all__

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__all__ = ("Environment", "Evm", "Message")

Environment

Items external to the virtual machine itself, provided by the environment.

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@dataclass
class Environment:

caller

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    caller: Address

block_hashes

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    block_hashes: List[Hash32]

origin

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    origin: Address

coinbase

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    coinbase: Address

number

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    number: Uint

gas_limit

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    gas_limit: Uint

gas_price

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    gas_price: Uint

time

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    time: U256

difficulty

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    difficulty: Uint

state

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    state: State

traces

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    traces: List[dict]

Message

Items that are used by contract creation or message call.

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@dataclass
class Message:

caller

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    caller: Address

target

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    target: Union[Bytes0, Address]

current_target

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    current_target: Address

gas

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    gas: Uint

value

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    value: U256

data

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    data: Bytes

code_address

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    code_address: Optional[Address]

code

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    code: Bytes

depth

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    depth: Uint

should_transfer_value

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    should_transfer_value: bool

is_static

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    is_static: bool

parent_evm

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    parent_evm: Optional["Evm"]

Evm

The internal state of the virtual machine.

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@dataclass
class Evm:

pc

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    pc: Uint

stack

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    stack: List[U256]

memory

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    memory: bytearray

code

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    code: Bytes

gas_left

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    gas_left: Uint

env

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    env: Environment

valid_jump_destinations

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    valid_jump_destinations: Set[Uint]

logs

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    logs: Tuple[Log, ...]

refund_counter

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    refund_counter: int

running

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    running: bool

message

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    message: Message

output

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    output: Bytes

accounts_to_delete

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    accounts_to_delete: Set[Address]

touched_accounts

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    touched_accounts: Set[Address]

return_data

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    return_data: Bytes

error

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    error: Optional[Exception]

incorporate_child_on_success

Incorporate the state of a successful child_evm into the parent evm.

Parameters

evm : The parent EVM. child_evm : The child evm to incorporate.

def incorporate_child_on_success(​evm: Evm, ​​child_evm: Evm​) -> None:
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    """
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    Incorporate the state of a successful `child_evm` into the parent `evm`.
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    Parameters
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    ----------
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    evm :
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        The parent `EVM`.
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    child_evm :
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        The child evm to incorporate.
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    """
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    evm.gas_left += child_evm.gas_left
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    evm.logs += child_evm.logs
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    evm.refund_counter += child_evm.refund_counter
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    evm.accounts_to_delete.update(child_evm.accounts_to_delete)
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    evm.touched_accounts.update(child_evm.touched_accounts)
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    if account_exists_and_is_empty(
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        evm.env.state, child_evm.message.current_target
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    ):
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        evm.touched_accounts.add(child_evm.message.current_target)

incorporate_child_on_error

Incorporate the state of an unsuccessful child_evm into the parent evm.

Parameters

evm : The parent EVM. child_evm : The child evm to incorporate.

def incorporate_child_on_error(​evm: Evm, ​​child_evm: Evm​) -> None:
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    """
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    Incorporate the state of an unsuccessful `child_evm` into the parent `evm`.
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    Parameters
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    ----------
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    evm :
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        The parent `EVM`.
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    child_evm :
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        The child evm to incorporate.
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    """
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    # In block 2675119, the empty account at 0x3 (the RIPEMD160 precompile) was
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    # cleared despite running out of gas. This is an obscure edge case that can
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    # only happen to a precompile.
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    # According to the general rules governing clearing of empty accounts, the
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    # touch should have been reverted. Due to client bugs, this event went
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    # unnoticed and 0x3 has been exempted from the rule that touches are
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    # reverted in order to preserve this historical behaviour.
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    if RIPEMD160_ADDRESS in child_evm.touched_accounts:
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        evm.touched_accounts.add(RIPEMD160_ADDRESS)
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    if child_evm.message.current_target == RIPEMD160_ADDRESS:
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        if account_exists_and_is_empty(
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            evm.env.state, child_evm.message.current_target
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        ):
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            evm.touched_accounts.add(RIPEMD160_ADDRESS)
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    evm.gas_left += child_evm.gas_left