ethereum.byzantium.vmethereum.constantinople.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") |
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Environment
Items external to the virtual machine itself, provided by the environment.
| 32 | @dataclass |
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class Environment:
caller
| 38 | caller: Address |
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block_hashes
| 39 | block_hashes: List[Hash32] |
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origin
| 40 | origin: Address |
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coinbase
| 41 | coinbase: Address |
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number
| 42 | number: Uint |
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gas_limit
| 43 | gas_limit: Uint |
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gas_price
| 44 | gas_price: Uint |
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time
| 45 | time: U256 |
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difficulty
| 46 | difficulty: Uint |
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state
| 47 | state: State |
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traces
| 48 | traces: List[dict] |
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Message
Items that are used by contract creation or message call.
| 51 | @dataclass |
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class Message:
caller
| 57 | caller: Address |
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target
| 58 | target: Union[Bytes0, Address] |
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current_target
| 59 | current_target: Address |
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gas
| 60 | gas: Uint |
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value
| 61 | value: U256 |
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data
| 62 | data: Bytes |
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code_address
| 63 | code_address: Optional[Address] |
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code
| 64 | code: Bytes |
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depth
| 65 | depth: Uint |
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should_transfer_value
| 66 | should_transfer_value: bool |
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is_static
| 67 | is_static: bool |
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parent_evm
| 68 | parent_evm: Optional["Evm"] |
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Evm
The internal state of the virtual machine.
| 71 | @dataclass |
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class Evm:
pc
| 75 | pc: Uint |
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stack
| 76 | stack: List[U256] |
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memory
| 77 | memory: bytearray |
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code
| 78 | code: Bytes |
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gas_left
| 79 | gas_left: Uint |
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env
| 80 | env: Environment |
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valid_jump_destinations
| 81 | valid_jump_destinations: Set[Uint] |
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logs
| 82 | logs: Tuple[Log, ...] |
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refund_counter
| 83 | refund_counter: int |
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running
| 84 | running: bool |
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message
| 85 | message: Message |
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output
| 86 | output: Bytes |
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accounts_to_delete
| 87 | accounts_to_delete: Set[Address] |
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touched_accounts
| 88 | touched_accounts: Set[Address] |
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return_data
| 89 | return_data: Bytes |
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error
| 90 | error: Optional[Exception] |
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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 | """ |
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| 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 |