ethereum.paris.vm.interpreterethereum.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
63 | STACK_DEPTH_LIMIT = Uint(1024) |
---|
MAX_CODE_SIZE
64 | MAX_CODE_SIZE = 0x6000 |
---|
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.current
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.current` 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 | block_env = message.block_env |
104 | refund_counter = U256(0) |
105 | if message.target == Bytes0(b""): |
106 | is_collision = account_has_code_or_nonce( |
107 | block_env.state, message.current_target |
108 | ) or account_has_storage(block_env.state, message.current_target) |
109 | if is_collision: |
110 | return MessageCallOutput( |
111 | Uint(0), U256(0), tuple(), set(), AddressCollision() |
112 | ) |
113 | else: |
114 | evm = process_create_message(message) |
115 | else: |
116 | evm = process_message(message) |
117 | |
118 | if evm.error: |
119 | logs: Tuple[Log, ...] = () |
120 | accounts_to_delete = set() |
121 | else: |
122 | logs = evm.logs |
123 | accounts_to_delete = evm.accounts_to_delete |
124 | refund_counter += U256(evm.refund_counter) |
125 | |
126 | tx_end = TransactionEnd( |
127 | int(message.gas) - int(evm.gas_left), evm.output, evm.error |
128 | ) |
129 | evm_trace(evm, tx_end) |
130 | |
131 | return MessageCallOutput( |
132 | gas_left=evm.gas_left, |
133 | refund_counter=refund_counter, |
134 | logs=logs, |
135 | accounts_to_delete=accounts_to_delete, |
136 | error=evm.error, |
137 | ) |
process_create_message
Executes a call to create a smart contract.
Parameters
message : Transaction specific items.
Returns
evm: :py:class:
Items containing execution specific objects.~ethereum.paris.vm.Evm~ethereum.shanghai.vm.Evm
def process_create_message(message: Message) -> Evm:
141 | """ |
---|---|
142 | Executes a call to create a smart contract. |
143 |
|
144 | Parameters |
145 | ---------- |
146 | message : |
147 | Transaction specific items. |
148 |
|
149 | Returns |
150 | ------- |
151 | evm: :py:class:`~ethereum.paris.vm.Evm` |
151 | evm: :py:class:`~ethereum.shanghai.vm.Evm` |
152 | Items containing execution specific objects. |
153 | """ |
154 | state = message.block_env.state |
155 | # take snapshot of state before processing the message |
156 | begin_transaction(state) |
157 | |
158 | # If the address where the account is being created has storage, it is |
159 | # destroyed. This can only happen in the following highly unlikely |
160 | # circumstances: |
161 | # * The address created by a `CREATE` call collides with a subsequent |
162 | # `CREATE` or `CREATE2` call. |
163 | # * The first `CREATE` happened before Spurious Dragon and left empty |
164 | # code. |
165 | destroy_storage(state, message.current_target) |
166 | |
167 | # In the previously mentioned edge case the preexisting storage is ignored |
168 | # for gas refund purposes. In order to do this we must track created |
169 | # accounts. |
170 | mark_account_created(state, message.current_target) |
171 | |
172 | increment_nonce(state, message.current_target) |
173 | evm = process_message(message) |
174 | if not evm.error: |
175 | contract_code = evm.output |
176 | contract_code_gas = Uint(len(contract_code)) * GAS_CODE_DEPOSIT |
177 | try: |
178 | if len(contract_code) > 0: |
179 | if contract_code[0] == 0xEF: |
180 | raise InvalidContractPrefix |
181 | charge_gas(evm, contract_code_gas) |
182 | if len(contract_code) > MAX_CODE_SIZE: |
183 | raise OutOfGasError |
184 | except ExceptionalHalt as error: |
185 | rollback_transaction(state) |
186 | evm.gas_left = Uint(0) |
187 | evm.output = b"" |
188 | evm.error = error |
189 | else: |
190 | set_code(state, message.current_target, contract_code) |
191 | commit_transaction(state) |
192 | else: |
193 | rollback_transaction(state) |
194 | return evm |
process_message
Move ether and execute the relevant code.
Parameters
message : Transaction specific items.
Returns
evm: :py:class:
Items containing execution specific objects~ethereum.paris.vm.Evm~ethereum.shanghai.vm.Evm
def process_message(message: Message) -> Evm:
198 | """ |
---|---|
199 | Move ether and execute the relevant code. |
200 |
|
201 | Parameters |
202 | ---------- |
203 | message : |
204 | Transaction specific items. |
205 |
|
206 | Returns |
207 | ------- |
208 | evm: :py:class:`~ethereum.paris.vm.Evm` |
208 | evm: :py:class:`~ethereum.shanghai.vm.Evm` |
209 | Items containing execution specific objects |
210 | """ |
211 | state = message.block_env.state |
212 | if message.depth > STACK_DEPTH_LIMIT: |
213 | raise StackDepthLimitError("Stack depth limit reached") |
214 | |
215 | # take snapshot of state before processing the message |
216 | begin_transaction(state) |
217 | |
218 | if message.should_transfer_value and message.value != 0: |
219 | move_ether( |
220 | state, message.caller, message.current_target, message.value |
221 | ) |
222 | |
223 | evm = execute_code(message) |
224 | if evm.error: |
225 | # revert state to the last saved checkpoint |
226 | # since the message call resulted in an error |
227 | rollback_transaction(state) |
228 | else: |
229 | commit_transaction(state) |
230 | return evm |
execute_code
Executes bytecode present in the message
.
Parameters
message : Transaction specific items.
Returns
evm: ethereum.vm.EVM
Items containing execution specific objects
def execute_code(message: Message) -> Evm:
234 | """ |
---|---|
235 | Executes bytecode present in the `message`. |
236 |
|
237 | Parameters |
238 | ---------- |
239 | message : |
240 | Transaction specific items. |
241 |
|
242 | Returns |
243 | ------- |
244 | evm: `ethereum.vm.EVM` |
245 | Items containing execution specific objects |
246 | """ |
247 | code = message.code |
248 | valid_jump_destinations = get_valid_jump_destinations(code) |
249 | |
250 | evm = Evm( |
251 | pc=Uint(0), |
252 | stack=[], |
253 | memory=bytearray(), |
254 | code=code, |
255 | gas_left=message.gas, |
256 | valid_jump_destinations=valid_jump_destinations, |
257 | logs=(), |
258 | refund_counter=0, |
259 | running=True, |
260 | message=message, |
261 | output=b"", |
262 | accounts_to_delete=set(), |
263 | return_data=b"", |
264 | error=None, |
265 | accessed_addresses=message.accessed_addresses, |
266 | accessed_storage_keys=message.accessed_storage_keys, |
267 | ) |
268 | try: |
269 | if evm.message.code_address in PRE_COMPILED_CONTRACTS: |
270 | evm_trace(evm, PrecompileStart(evm.message.code_address)) |
271 | PRE_COMPILED_CONTRACTS[evm.message.code_address](evm) |
272 | evm_trace(evm, PrecompileEnd()) |
273 | return evm |
274 |
|
275 | while evm.running and evm.pc < ulen(evm.code): |
276 | try: |
277 | op = Ops(evm.code[evm.pc]) |
278 | except ValueError: |
279 | raise InvalidOpcode(evm.code[evm.pc]) |
280 |
|
281 | evm_trace(evm, OpStart(op)) |
282 | op_implementation[op](evm) |
283 | evm_trace(evm, OpEnd()) |
284 |
|
285 | evm_trace(evm, EvmStop(Ops.STOP)) |
286 |
|
287 | except ExceptionalHalt as error: |
288 | evm_trace(evm, OpException(error)) |
289 | evm.gas_left = Uint(0) |
290 | evm.output = b"" |
291 | evm.error = error |
292 | except Revert as error: |
293 | evm_trace(evm, OpException(error)) |
294 | evm.error = error |
295 | return evm |