Zabi

InstructionErrors

Set of common errors when running indivual instructions.

Allocator.Error || error{ StackUnderflow, StackOverflow, Overflow } || GasTracker.Error

AllInstructionErrors

Set of all possible errors of interpreter instructions.

InstructionErrors || Memory.Error || error{
    UnexpectedError,
    InvalidJump,
    InstructionNotEnabled,
}

InterpreterRunErrors

Set of possible errors when running the interpreter.

AllInstructionErrors || error{
    OpcodeNotFound,
    InvalidInstructionOpcode,
    InterpreterReverted,
    InvalidOffset,
    CallWithValueNotAllowedInStaticCall,
    CreateCodeSizeLimit,
}

InterpreterStatusErrors

Set of possible errors that can be returned depending on the interpreter's current state.

error{
    OpcodeNotFound,
    CallWithValueNotAllowedInStaticCall,
    InvalidInstructionOpcode,
    InterpreterReverted,
    CreateCodeSizeLimit,
    InvalidOffset,
    InvalidJump,
}

InterpreterActions

The set of next interpreter actions.

Properties

union(enum) {
  /// Call action.
  call_action: CallAction
  /// Create action.
  create_action: CreateAction
  /// Return action.
  return_action: ReturnAction
  /// No action for the interpreter to take.
  no_action
}

Deinit

Clears any memory with the associated action.

Signature

pub fn deinit(self: @This(), allocator: Allocator) void

InterpreterStatus

The status of execution for the interpreter.

Properties

enum {
  call_or_create
  call_with_value_not_allowed_in_static_call
  create_code_size_limit
  invalid
  invalid_jump
  invalid_offset
  opcode_not_found
  returned
  reverted
  running
  self_destructed
  stopped
}

InterpreterInitOptions

Set of default options that the interperter needs for it to be able to run.

Properties

struct {
  /// Maximum amount of gas available to perform the operations
  gas_limit: u64 = 30_000_000
  /// Tells the interperter if it's going to run as a static call
  is_static: bool = false
  /// Sets the interperter spec based on the hardforks.
  spec_id: SpecId = .LATEST
}

Init

Sets the interpreter to it's expected initial state.

Copy's the contract's bytecode independent of it's state.

Example

const contract_instance = try Contract.init(
    testing.allocator,
    &.{},
    .{ .raw = @constCast(&[_]u8{ 0x60, 0x01, 0x60, 0x02, 0x01 }) },
    null,
    0,
    [_]u8{1} ** 20,
    [_]u8{0} ** 20,
);
defer contract_instance.deinit(testing.allocator);
 
var plain: PlainHost = undefined;
defer plain.deinit();
 
plain.init(testing.allocator);
 
var interpreter: Interpreter = undefined;
defer interpreter.deinit();
 
try interpreter.init(testing.allocator, contract_instance, plain.host(), .{});

Signature

pub fn init(
    self: *Interpreter,
    allocator: Allocator,
    contract_instance: Contract,
    evm_host: Host,
    opts: InterpreterInitOptions,
) Allocator.Error!void

AdvanceProgramCounter

Moves the program_counter by one.

Signature

pub fn advanceProgramCounter(self: *Interpreter) void

RunInstruction

Runs a single instruction based on the program_counter position and the associated bytecode. Doesn't move the counter.

Signature

pub fn runInstruction(self: *Interpreter) AllInstructionErrors!void

Run

Runs the associated contract bytecode.

Depending on the interperter final status this can return errors.
The bytecode that will get run will be padded with STOP instructions at the end to make sure that we don't have index out of bounds panics.

Example

const contract_instance = try Contract.init(
    testing.allocator,
    &.{},
    .{ .raw = @constCast(&[_]u8{ 0x60, 0x01, 0x60, 0x02, 0x01 }) },
    null,
    0,
    [_]u8{1} ** 20,
    [_]u8{0} ** 20,
);
defer contract_instance.deinit(testing.allocator);
 
var plain: PlainHost = undefined;
defer plain.deinit();
 
plain.init(testing.allocator);
 
var interpreter: Interpreter = undefined;
defer interpreter.deinit();
 
try interpreter.init(testing.allocator, contract_instance, plain.host(), .{});
 
const result = try interpreter.run();
defer result.deinit(testing.allocator);

Signature

pub fn run(self: *Interpreter) (AllInstructionErrors || InterpreterStatusErrors)!InterpreterActions

Resize

Resizes the inner memory size. Adds gas expansion cost to the gas tracker.

Signature

pub fn resize(self: *Interpreter, new_size: usize) (Allocator.Error || GasTracker.Error || Memory.Error)!void