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__

29
__all__ = ("Environment", "Evm", "Message")

Environment

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

32
@dataclass
class Environment:

caller

38
    caller: Address

block_hashes

39
    block_hashes: List[Hash32]

origin

40
    origin: Address

coinbase

41
    coinbase: Address

number

42
    number: Uint

gas_limit

43
    gas_limit: Uint

gas_price

44
    gas_price: Uint

time

45
    time: U256

difficulty

46
    difficulty: Uint

state

47
    state: State

traces

48
    traces: List[dict]

Message

Items that are used by contract creation or message call.

51
@dataclass
class Message:

caller

57
    caller: Address

target

58
    target: Union[Bytes0, Address]

current_target

59
    current_target: Address

gas

60
    gas: Uint

value

61
    value: U256

data

62
    data: Bytes

code_address

63
    code_address: Optional[Address]

code

64
    code: Bytes

depth

65
    depth: Uint

should_transfer_value

66
    should_transfer_value: bool

is_static

67
    is_static: bool

parent_evm

68
    parent_evm: Optional["Evm"]

Evm

The internal state of the virtual machine.

71
@dataclass
class Evm:

pc

75
    pc: Uint

stack

76
    stack: List[U256]

memory

77
    memory: bytearray

code

78
    code: Bytes

gas_left

79
    gas_left: Uint

env

80
    env: Environment

valid_jump_destinations

81
    valid_jump_destinations: Set[Uint]

logs

82
    logs: Tuple[Log, ...]

refund_counter

83
    refund_counter: int

running

84
    running: bool

message

85
    message: Message

output

86
    output: Bytes

accounts_to_delete

87
    accounts_to_delete: Set[Address]

touched_accounts

88
    touched_accounts: Set[Address]

return_data

89
    return_data: Bytes

error

90
    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:
94
    """
95
    Incorporate the state of a successful `child_evm` into the parent `evm`.
96
97
    Parameters
98
    ----------
99
    evm :
100
        The parent `EVM`.
101
    child_evm :
102
        The child evm to incorporate.
103
    """
104
    evm.gas_left += child_evm.gas_left
105
    evm.logs += child_evm.logs
106
    evm.refund_counter += child_evm.refund_counter
107
    evm.accounts_to_delete.update(child_evm.accounts_to_delete)
108
    evm.touched_accounts.update(child_evm.touched_accounts)
109
    if account_exists_and_is_empty(
110
        evm.env.state, child_evm.message.current_target
111
    ):
112
        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:
116
    """
117
    Incorporate the state of an unsuccessful `child_evm` into the parent `evm`.
118
119
    Parameters
120
    ----------
121
    evm :
122
        The parent `EVM`.
123
    child_evm :
124
        The child evm to incorporate.
125
    """
126
    # In block 2675119, the empty account at 0x3 (the RIPEMD160 precompile) was
127
    # cleared despite running out of gas. This is an obscure edge case that can
128
    # only happen to a precompile.
129
    # According to the general rules governing clearing of empty accounts, the
130
    # touch should have been reverted. Due to client bugs, this event went
131
    # unnoticed and 0x3 has been exempted from the rule that touches are
132
    # reverted in order to preserve this historical behaviour.
133
    if RIPEMD160_ADDRESS in child_evm.touched_accounts:
134
        evm.touched_accounts.add(RIPEMD160_ADDRESS)
135
    if child_evm.message.current_target == RIPEMD160_ADDRESS:
136
        if account_exists_and_is_empty(
137
            evm.env.state, child_evm.message.current_target
138
        ):
139
            evm.touched_accounts.add(RIPEMD160_ADDRESS)
140
    evm.gas_left += child_evm.gas_left