ethereum.forks.shanghai.vm.runtimeethereum.forks.cancun.vm.runtime
Ethereum Virtual Machine (EVM) Runtime Operations.
.. contents:: Table of Contents :backlinks: none :local:
Introduction
Runtime related operations used while executing EVM code.
get_valid_jump_destinations
Analyze the evm code to obtain the set of valid jump destinations.
Valid jump destinations are defined as follows:
* The jump destination is less than the length of the code.
* The jump destination should have the JUMPDEST
opcode (0x5B).
* The jump destination shouldn't be part of the data corresponding to
PUSH-N
opcodes.
Note - Jump destinations are 0-indexed.
Parameters
code : The EVM code which is to be executed.
Returns
valid_jump_destinations: Set[Uint]
The set of valid jump destinations in the code.
def get_valid_jump_destinations(code: Bytes) -> Set[Uint]:
23 | """ |
---|---|
24 | Analyze the evm code to obtain the set of valid jump destinations. |
25 |
|
26 | Valid jump destinations are defined as follows: |
27 | * The jump destination is less than the length of the code. |
28 | * The jump destination should have the `JUMPDEST` opcode (0x5B). |
29 | * The jump destination shouldn't be part of the data corresponding to |
30 | `PUSH-N` opcodes. |
31 |
|
32 | Note - Jump destinations are 0-indexed. |
33 |
|
34 | Parameters |
35 | ---------- |
36 | code : |
37 | The EVM code which is to be executed. |
38 |
|
39 | Returns |
40 | ------- |
41 | valid_jump_destinations: `Set[Uint]` |
42 | The set of valid jump destinations in the code. |
43 |
|
44 | """ |
45 | valid_jump_destinations = set() |
46 | pc = Uint(0) |
47 | |
48 | while pc < ulen(code): |
49 | try: |
50 | current_opcode = Ops(code[pc]) |
51 | except ValueError: |
52 | # Skip invalid opcodes, as they don't affect the jumpdest |
53 | # analysis. Nevertheless, such invalid opcodes would be caught |
54 | # and raised when the interpreter runs. |
55 | pc += Uint(1) |
56 | continue |
57 |
|
58 | if current_opcode == Ops.JUMPDEST: |
59 | valid_jump_destinations.add(pc) |
60 | elif Ops.PUSH1.value <= current_opcode.value <= Ops.PUSH32.value: |
61 | # If PUSH-N opcodes are encountered, skip the current opcode along |
62 | # with the trailing data segment corresponding to the PUSH-N |
63 | # opcodes. |
64 | push_data_size = current_opcode.value - Ops.PUSH1.value + 1 |
65 | pc += Uint(push_data_size) |
66 |
|
67 | pc += Uint(1) |
68 | |
69 | return valid_jump_destinations |