ethereum.tangerine_whistle.vm.interpreterethereum.spurious_dragon.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 |
---|
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.
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. `touched_accounts`: Accounts that have been touched.
6. `error`: The error from the execution if any.
66 | @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] |
---|
touched_accounts
85 | touched_accounts: Set[Address] |
---|
error
86 | 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:
90 | """ |
---|---|
91 | If `message.current` is empty then it creates a smart contract |
92 | else it executes a call from the `message.caller` to the `message.target`. |
93 |
|
94 | Parameters |
95 | ---------- |
96 | message : |
97 | Transaction specific items. |
98 |
|
99 | Returns |
100 | ------- |
101 | output : `MessageCallOutput` |
102 | Output of the message call |
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( |
106 | Uint(0), U256(0), tuple(), set(), AddressCollision() |
112 | Uint(0), U256(0), tuple(), set(), set(), AddressCollision() |
113 | ) |
114 | else: |
115 | evm = process_create_message(message) |
116 | else: |
111 | evm = process_message(message) |
117 | evm = process_message(message) |
118 | if account_exists_and_is_empty( |
119 | block_env.state, Address(message.target) |
120 | ): |
121 | evm.touched_accounts.add(Address(message.target)) |
122 | |
123 | if evm.error: |
124 | logs: Tuple[Log, ...] = () |
115 | accounts_to_delete = set() |
125 | accounts_to_delete = set() |
126 | touched_accounts = set() |
127 | else: |
128 | logs = evm.logs |
129 | accounts_to_delete = evm.accounts_to_delete |
130 | touched_accounts = evm.touched_accounts |
131 | refund_counter += U256(evm.refund_counter) |
132 | |
133 | tx_end = TransactionEnd( |
134 | int(message.gas) - int(evm.gas_left), evm.output, evm.error |
135 | ) |
136 | evm_trace(evm, tx_end) |
137 | |
138 | return MessageCallOutput( |
139 | gas_left=evm.gas_left, |
140 | refund_counter=refund_counter, |
141 | logs=logs, |
142 | accounts_to_delete=accounts_to_delete, |
143 | touched_accounts=touched_accounts, |
144 | error=evm.error, |
145 | ) |
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.tangerine_whistle.vm.Evm~ethereum.spurious_dragon.vm.Evm
def process_create_message(message: Message) -> Evm:
149 | """ |
---|---|
150 | Executes a call to create a smart contract. |
151 |
|
152 | Parameters |
153 | ---------- |
154 | message : |
155 | Transaction specific items. |
156 |
|
157 | Returns |
158 | ------- |
146 | evm: :py:class:`~ethereum.tangerine_whistle.vm.Evm` |
159 | evm: :py:class:`~ethereum.spurious_dragon.vm.Evm` |
160 | Items containing execution specific objects. |
161 | """ |
162 | state = message.block_env.state |
163 | # take snapshot of state before processing the message |
164 | begin_transaction(state) |
165 | |
166 | # If the address where the account is being created has storage, it is |
167 | # destroyed. This can only happen in the following highly unlikely |
168 | # circumstances: |
169 | # * The address created by two `CREATE` calls collide. |
157 | # * The first `CREATE` left empty code. |
170 | # * The first `CREATE` happened before Spurious Dragon and left empty |
171 | # code. |
172 | destroy_storage(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: |
165 | charge_gas(evm, contract_code_gas) |
180 | charge_gas(evm, contract_code_gas) |
181 | if len(contract_code) > MAX_CODE_SIZE: |
182 | raise OutOfGasError |
183 | except ExceptionalHalt as error: |
184 | rollback_transaction(state) |
185 | evm.gas_left = Uint(0) |
186 | evm.error = error |
187 | else: |
188 | set_code(state, message.current_target, contract_code) |
189 | commit_transaction(state) |
190 | else: |
191 | rollback_transaction(state) |
192 | 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.tangerine_whistle.vm.Evm~ethereum.spurious_dragon.vm.Evm
def process_message(message: Message) -> Evm:
196 | """ |
---|---|
197 | Move ether and execute the relevant code. |
198 |
|
199 | Parameters |
200 | ---------- |
201 | message : |
202 | Transaction specific items. |
203 |
|
204 | Returns |
205 | ------- |
189 | evm: :py:class:`~ethereum.tangerine_whistle.vm.Evm` |
206 | evm: :py:class:`~ethereum.spurious_dragon.vm.Evm` |
207 | Items containing execution specific objects |
208 | """ |
209 | state = message.block_env.state |
210 | if message.depth > STACK_DEPTH_LIMIT: |
211 | raise StackDepthLimitError("Stack depth limit reached") |
212 | |
213 | # take snapshot of state before processing the message |
214 | begin_transaction(state) |
215 | |
216 | touch_account(state, message.current_target) |
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 | touched_accounts=set(), |
264 | error=None, |
265 | ) |
266 | try: |
267 | if evm.message.code_address in PRE_COMPILED_CONTRACTS: |
268 | evm_trace(evm, PrecompileStart(evm.message.code_address)) |
269 | PRE_COMPILED_CONTRACTS[evm.message.code_address](evm) |
270 | evm_trace(evm, PrecompileEnd()) |
271 | return evm |
272 |
|
273 | while evm.running and evm.pc < ulen(evm.code): |
274 | try: |
275 | op = Ops(evm.code[evm.pc]) |
276 | except ValueError: |
277 | raise InvalidOpcode(evm.code[evm.pc]) |
278 |
|
279 | evm_trace(evm, OpStart(op)) |
280 | op_implementation[op](evm) |
281 | evm_trace(evm, OpEnd()) |
282 |
|
283 | evm_trace(evm, EvmStop(Ops.STOP)) |
284 |
|
285 | except ExceptionalHalt as error: |
286 | evm_trace(evm, OpException(error)) |
287 | evm.gas_left = Uint(0) |
288 | evm.error = error |
289 | return evm |