def label_blocks(contract):
"""
Label all the blocks
"""
for block in contract.blocks:
for index, instruction in enumerate(block.instructions):
if not opcodes.is_push(instruction.op):
continue
if instruction.arg not in contract.jump_destination.keys():
continue
destination = instruction.destination
for operand_pointer in destination:
instruction_pointer = operand_pointer.instruction_pointer
destination_instruction = get_instruction(instruction_pointer)
if destination_instruction.name != 'JUMPI' and destination_instruction.name != 'JUMP':
break
elif operand_pointer.pos != 0:
break
else:
target_block = contract.jump_destination[instruction.arg]
target_block.label = -1
identity = 0
for block in contract.blocks:
if block.label is not None:
block.label = identity
identity += 1
def print_analysis_result(analyzed_contract):
"""
Print the analysis result
"""
result = ''
for block in analyzed_contract.blocks:
label = block.label
if label is not None:
result += ':label{}\n'.format(label)
offset = block.offset
for instruction in block.instructions:
op = instruction.op
name = instruction.name
if opcodes.is_push(op):
arg = instruction.arg
result += '{:#x}\t{} {:#x}\n'.format(offset, name, arg)
elif name == 'JUMPI' or name == 'JUMP':
result += '{:#x}\t{} '.format(offset, name)
source_instruction_set = instruction.source[0]
for pointer in source_instruction_set:
source_instruction = analyze.get_instruction(pointer)
target_label = analyzed_contract.jump_destination[
source_instruction.arg].label
result += ':label{} '.format(target_label)
result = result[:-1] + '\n'
else:
result += '{:#x}\t{}\n'.format(offset, name)
offset += opcodes.operand_size(op) + 1
result += '\n'
print(result)
def instruction_to_bytecode(instr):
"""
Convert instruction to bytecode
"""
op = instr.op
evm = bytearray(op.to_bytes(1, byteorder='big'))
if opcodes.is_push(op):
arg = instr.arg
size = opcodes.operand_size(op)
evm += bytearray(arg.to_bytes(size, byteorder='big'))
return evm
def advance(state):
"""
Execute next block abstractly and advance the current state
"""
contract = state.contract
block = state.next_block
pc = state.next_block.offset
stack = state.stack.copy()
update_block_source(block, stack, len(stack))
for index, instruction in enumerate(state.next_block.instructions):
op = instruction.op
name = instruction.name
old_stack = stack.copy()
ins = opcodes.opcodes[op][1]
operands = []
for i in range(ins):
operand = stack.pop(0)
operands.append(operand)
update_instruction_source(instruction, operands, ins)
if name == 'STOP' or name == 'RETURN' or name == 'REVERT' or name == 'SUICIDE':
return []
elif opcodes.is_push(op):
stack.insert(0, InstructionPointer(state.next_block, index))
elif opcodes.is_dup(op):
old_stack.insert(0, operands[-1])
stack = old_stack
elif opcodes.is_swap(op):
tmp = old_stack[0]
old_stack[0] = old_stack[ins - 1]
old_stack[ins - 1] = tmp
stack = old_stack
elif name == 'JUMP':
source_instruction = get_instruction(operands[0])
if not opcodes.is_push(source_instruction.op):
raise TypeError(
'Error resolving JUMP address. pc: {:#x}, source: {:#x}'.
format(pc, get_instruction_offset(operands[0])))
if source_instruction.arg not in contract.jump_destination.keys():
raise KeyError(
'Invalid JUMP address. pc: {:#x}, source: {:#x}, addr: {:#x}'
.format(pc, get_instruction_offset(operands[0]),
source_instruction.arg))
return [
State(contract,
contract.jump_destination[source_instruction.arg], stack)
]
elif name == 'JUMPI':
source_instruction = get_instruction(operands[0])
if not opcodes.is_push(source_instruction.op):
raise ValueError(
'Error resolving JUMP address. pc: {:#x}, source: {:#x}'.
format(pc, get_instruction_offset(operands[0])))
if source_instruction.arg not in contract.jump_destination.keys():
raise KeyError(
'Invalid JUMP address. pc: {:#x}, source: {:#x}, addr: {:#x}'
.format(pc, get_instruction_offset(operands[0]),
source_instruction.arg))
ret = [
State(contract,
contract.jump_destination[source_instruction.arg], stack)
]
if state.next_block.next is not None:
ret.append(State(contract, state.next_block.next, stack))
return ret
else:
outs = opcodes.opcodes[op][2]
for i in range(outs):
stack.insert(0, InstructionPointer(state.next_block, index))
if len(stack) > 1024:
log.critical('Stack overflow. pc: {:#x}'.format(pc))
return []
size = opcodes.operand_size(op)
pc += size + 1
if state.next_block.next is not None:
return [State(contract, state.next_block.next, stack)]
else:
return []
def advance(elm):
"""
Execute next block abstractly and advance current state
"""
global contr
global trace
global relocate
stat = elm.state
blk = stat.next_block
pc = blk.offset
stack = stat.stack.copy()
memory = stat.memory.copy()
storage = stat.storage.copy()
sequence = stat.sequence.copy()
# Mark current state as executed
elm.executed = True
for instr in blk.instructions:
op = instr.op
name = instr.name
old_stack = stack.copy()
ins = opcodes.listing[op][1]
if ins > len(stack):
raise RuntimeError('Stack underflow. pc: {:#x}'.format(pc))
operands = []
for i in range(ins):
operand = stack.pop(0)
operands.append(operand)
backtrack_instruction_sources(pc, instr, operands, ins)
# Trace executed instructions from CALL to SSTORE, omit JUMPDEST, SWAP and DUP
if name != 'JUMPDEST' and not opcodes.is_swap(op) and not opcodes.is_dup(op):
for off in sequence:
sequence[off].add(pc)
if name == 'STOP' or name == 'SUICIDE':
# Current block is NOT revert block
return False
elif name == 'INVALID':
# Current block is revert block
return True
elif name == 'ADD':
op0 = operands[0].value
op1 = operands[1].value
if op0 is not None and op1 is not None:
stack.insert(0, OperandStackElement(pc, instr, (op0 + op1) & TT256M1))
else:
stack.insert(0, OperandStackElement(pc, instr))
elif name == 'SUB':
op0 = operands[0].value
op1 = operands[1].value
if op0 is not None and op1 is not None:
stack.insert(0, OperandStackElement(pc, instr, (op0 - op1) & TT256M1))
else:
stack.insert(0, OperandStackElement(pc, instr))
elif name == 'MUL':
op0 = operands[0].value
op1 = operands[1].value
if op0 is not None and op1 is not None:
stack.insert(0, OperandStackElement(pc, instr, (op0 * op1) & TT256M1))
else:
stack.insert(0, OperandStackElement(pc, instr))
elif name == 'DIV':
op0 = operands[0].value
op1 = operands[1].value
if op0 is not None and op1 is not None:
stack.insert(0, OperandStackElement(pc, instr, 0 if op1 == 0 else op0 // op1))
else:
stack.insert(0, OperandStackElement(pc, instr))
elif name == 'MOD':
op0 = operands[0].value
op1 = operands[1].value
if op0 is not None and op1 is not None:
stack.insert(0, OperandStackElement(pc, instr, 0 if op1 == 0 else op0 % op1))
else:
stack.insert(0, OperandStackElement(pc, instr))
elif name == 'SDIV':
op0 = convert_to_signed(operands[0].value)
op1 = convert_to_signed(operands[1].value)
if op0 is not None and op1 is not None:
stack.insert(0, OperandStackElement(pc, instr,
0 if op1 == 0 else (abs(op0) // abs(op1) *
(-1 if op0 * op1 < 0 else 1)) & TT256M1))
else:
stack.insert(0, OperandStackElement(pc, instr))
elif name == 'SMOD':
op0 = convert_to_signed(operands[0].value)
op1 = convert_to_signed(operands[1].value)
if op0 is not None and op1 is not None:
stack.insert(0, OperandStackElement(pc, instr,
0 if op1 == 0 else (abs(op0) % abs(op1) *
(-1 if op0 < 0 else 1)) & TT256M1))
else:
stack.insert(0, OperandStackElement(pc, instr))
elif name == 'ADDMOD':
op0 = operands[0].value
op1 = operands[1].value
op2 = operands[2].value
if op0 is not None and op1 is not None and op2 is not None:
stack.insert(0, OperandStackElement(pc, instr, (op0 + op1) % op2 if op2 else 0))
else:
stack.insert(0, OperandStackElement(pc, instr))
elif name == 'MULMOD':
op0 = operands[0].value
op1 = operands[1].value
op2 = operands[2].value
if op0 is not None and op1 is not None and op2 is not None:
stack.insert(0, OperandStackElement(pc, instr, (op0 * op1) % op2 if op2 else 0))
else:
stack.insert(0, OperandStackElement(pc, instr))
elif name == 'EXP':
base = operands[0].value
exponent = operands[1].value
if base is not None and exponent is not None:
stack.insert(0, OperandStackElement(pc, instr, pow(base, exponent, TT256)))
else:
stack.insert(0, OperandStackElement(pc, instr))
elif name == 'SIGNEXTEND':
op0 = operands[0].value
op1 = operands[1].value
if op0 is not None and op1 is not None:
if op0 <= 31:
test_bit = op0 * 8 + 7
if op1 & (1 << test_bit):
stack.insert(0, OperandStackElement(pc, instr, op1 | (TT256 - (1 << test_bit))))
else:
stack.insert(0, OperandStackElement(pc, instr, op1 & ((1 << test_bit) - 1)))
else:
stack.insert(0, OperandStackElement(pc, instr, op1))
else:
stack.insert(0, OperandStackElement(pc, instr))
elif name == 'LT':
op0 = operands[0].value
op1 = operands[1].value
if op0 is not None and op1 is not None:
stack.insert(0, OperandStackElement(pc, instr, 1 if op0 < op1 else 0))
else:
stack.insert(0, OperandStackElement(pc, instr))
elif name == 'GT':
op0 = operands[0].value
op1 = operands[1].value
if op0 is not None and op1 is not None:
stack.insert(0, OperandStackElement(pc, instr, 1 if op0 > op1 else 0))
else:
stack.insert(0, OperandStackElement(pc, instr))
elif name == 'SLT':
op0 = convert_to_signed(operands[0].value)
op1 = convert_to_signed(operands[1].value)
if op0 is not None and op1 is not None:
stack.insert(0, OperandStackElement(pc, instr, 1 if op0 < op1 else 0))
else:
stack.insert(0, OperandStackElement(pc, instr))
elif name == 'SGT':
op0 = convert_to_signed(operands[0].value)
op1 = convert_to_signed(operands[1].value)
if op0 is not None and op1 is not None:
stack.insert(0, OperandStackElement(pc, instr, 1 if op0 > op1 else 0))
else:
stack.insert(0, OperandStackElement(pc, instr))
elif name == 'EQ':
op0 = operands[0].value
op1 = operands[1].value
if op0 is not None and op1 is not None:
stack.insert(0, OperandStackElement(pc, instr, 1 if op0 == op1 else 0))
else:
stack.insert(0, OperandStackElement(pc, instr))
elif name == 'ISZERO':
op0 = operands[0].value
if op0 is not None:
stack.insert(0, OperandStackElement(pc, instr, 0 if op0 else 1))
else:
stack.insert(0, OperandStackElement(pc, instr))
elif name == 'AND':
op0 = operands[0].value
op1 = operands[1].value
if op0 is not None and op1 is not None:
if op0 == 0xffffffff:
stack.insert(0, OperandStackElement(pc, instr, op0 & op1, operands[1].source))
elif op1 == 0xffffffff:
stack.insert(0, OperandStackElement(pc, instr, op0 & op1, operands[0].source))
else:
stack.insert(0, OperandStackElement(pc, instr, op0 & op1))
else:
stack.insert(0, OperandStackElement(pc, instr))
elif name == 'OR':
op0 = operands[0].value
op1 = operands[1].value
if op0 is not None and op1 is not None:
stack.insert(0, OperandStackElement(pc, instr, op0 | op1))
else:
stack.insert(0, OperandStackElement(pc, instr))
elif name == 'XOR':
op0 = operands[0].value
op1 = operands[1].value
if op0 is not None and op1 is not None:
stack.insert(0, OperandStackElement(pc, instr, op0 ^ op1))
else:
stack.insert(0, OperandStackElement(pc, instr))
elif name == 'NOT':
op0 = operands[0].value
if op0 is not None:
stack.insert(0, OperandStackElement(pc, instr, TT256M1 - op0))
else:
stack.insert(0, OperandStackElement(pc, instr))
elif name == 'BYTE':
op0 = operands[0].value
op1 = operands[1].value
if op0 is not None and op1 is not None:
if op0 >= 32:
stack.insert(0, OperandStackElement(pc, instr, 0))
else:
stack.insert(0, OperandStackElement(pc, instr, (op1 // 256 ** (31 - op0)) % 256))
else:
stack.insert(0, OperandStackElement(pc, instr))
elif name == 'RETURN':
address = operands[0].value
size = operands[1].value
# Resolve read address and read size, record memory dependencies
if address is not None and size is not None:
for i in range(size):
if address + i in memory:
instr.dependence.update(memory[address + i])
if 'all' in memory:
instr.dependence.update(memory['all'])
# Can not resolve read address or read size, record all possible memory dependencies
else:
for addr in memory:
instr.dependence.update(memory[addr])
# Current block is NOT revert block
return False
elif name == 'REVERT':
address = operands[0].value
size = operands[1].value
# Resolve read address and read size, record memory dependencies
if address is not None and size is not None:
for i in range(size):
if address + i in memory:
instr.dependence.update(memory[address + i])
if 'all' in memory:
instr.dependence.update(memory['all'])
# Can not resolve read address or read size, record all possible memory dependencies
else:
for addr in memory:
instr.dependence.update(memory[addr])
# Current block is revert block
return True
elif opcodes.is_push(op):
stack.insert(0, OperandStackElement(pc, instr, instr.arg, pc))
elif opcodes.is_dup(op):
old_stack.insert(0, operands[-1])
stack = old_stack
elif opcodes.is_swap(op):
tmp = old_stack[0]
old_stack[0] = old_stack[ins - 1]
old_stack[ins - 1] = tmp
stack = old_stack
elif name == 'JUMP':
src_pc = operands[0].source
dst_pc = operands[0].value
if src_pc is None or dst_pc is None:
raise ValueError('Error resolving JUMP address. pc: {:#x}, source: {:#x}'
.format(pc, operands[0].pc))
if dst_pc not in contr.jump_destination:
# Current block is revert block
return True
else:
dst_blk = contr.jump_destination[dst_pc]
# Construct relocation table
relocate.sources[src_pc] = None
relocate.destinations[dst_pc] = None
# Add CFG edges, representing control flow dependencies between basic blocks
cfg.graph.add_edge(blk.offset, dst_blk.offset, type='JUMP')
# Update number of return values to wait
elm.num += 1
return [State(dst_blk, stack, memory, storage, sequence)]
elif name == 'JUMPI':
src_pc = operands[0].source
dst_pc = operands[0].value
if src_pc is None or dst_pc is None:
raise ValueError('Error resolving JUMPI address. pc: {:#x}, source: {:#x}'
.format(pc, operands[0].pc))
ret = []
if dst_pc in contr.jump_destination:
dst_blk = contr.jump_destination[dst_pc]
# Construct relocation table
relocate.sources[src_pc] = None
relocate.destinations[dst_pc] = None
# Add CFG edges, representing control flow dependencies between basic blocks
cfg.graph.add_edge(blk.offset, dst_blk.offset, type='JUMPI')
# Update number of return values to wait
elm.num += 1
ret.append(State(dst_blk, stack, memory, storage, sequence))
if blk.next is not None:
# Add CFG edges, representing control flow dependencies between basic blocks
cfg.graph.add_edge(blk.offset, blk.next.offset, type='JUMPI')
# Update number of return values to wait
elm.num += 1
ret.append(State(blk.next, stack, memory, storage, sequence))
if not ret:
# Current block is revert block
return True
else:
return ret
elif name == 'SHA3':
address = operands[0].value
size = operands[1].value
# Resolve read address and read size, record memory dependencies
if address is not None and size is not None:
for i in range(size):
if address + i in memory:
instr.dependence.update(memory[address + i])
if 'all' in memory:
instr.dependence.update(memory['all'])
# Can not resolve read address or read size, record all possible memory dependencies
else:
for addr in memory:
instr.dependence.update(memory[addr])
stack.insert(0, OperandStackElement(pc, instr))
elif name == 'LOG0' or name == 'LOG1' or name == 'LOG2' or name == 'LOG3' or name == 'LOG4':
address = operands[0].value
size = operands[1].value
# Resolve read address and read size, record memory dependencies
if address is not None and size is not None:
for i in range(size):
if address + i in memory:
instr.dependence.update(memory[address + i])
if 'all' in memory:
instr.dependence.update(memory['all'])
# Can not resolve read address or read size, record all possible memory dependencies
else:
for addr in memory:
instr.dependence.update(memory[addr])
elif name == 'MLOAD':
address = operands[0].value
# Resolve read address, record memory dependencies
if address is not None:
for i in range(32):
if address + i in memory:
instr.dependence.update(memory[address + i])
if 'all' in memory:
instr.dependence.update(memory['all'])
# Can not resolve read address, record all possible memory dependencies
else:
for addr in memory:
instr.dependence.update(memory[addr])
stack.insert(0, OperandStackElement(pc, instr))
elif name == 'CREATE':
address = operands[0].value
size = operands[1].value
# Resolve read address and read size, record memory dependencies
if address is not None and size is not None:
for i in range(size):
if address + i in memory:
instr.dependence.update(memory[address + i])
if 'all' in memory:
instr.dependence.update(memory['all'])
# Can not resolve read address or read size, record all possible memory dependencies
else:
for addr in memory:
instr.dependence.update(memory[addr])
stack.insert(0, OperandStackElement(pc, instr))
elif name == 'MSTORE':
address = operands[0].value
# Resolve write address, label memory
if address is not None:
for i in range(32):
if address + i not in memory:
memory[address + i] = set()
instr.overwrite.update(memory[address + i])
memory[address + i].add(pc)
# Can not resolve write address, label all possible addresses
else:
if 'all' not in memory:
memory['all'] = set()
for addr in memory:
instr.overwrite.update(memory[addr])
memory['all'].add(pc)
elif name == 'MSTORE8':
address = operands[0].value
# Resolve write address, label memory
if address is not None:
if address not in memory:
memory[address] = set()
instr.overwrite.update(memory[address])
memory[address].add(pc)
# Can not resolve write address, label all possible addresses
else:
if 'all' not in memory:
memory['all'] = set()
for addr in memory:
instr.overwrite.update(memory[addr])
memory['all'].add(pc)
elif name == 'CALLDATACOPY' or name == 'RETURNDATACOPY':
address = operands[0].value
size = operands[2].value
# Resolve write address and write size, label memory
if address is not None and size is not None:
for i in range(size):
if address + i not in memory:
memory[address + i] = set()
instr.overwrite.update(memory[address + i])
memory[address + i].add(pc)
# Can not resolve write address or write size, label all possible addresses
else:
if 'all' not in memory:
memory['all'] = set()
for addr in memory:
instr.overwrite.update(memory[addr])
memory['all'].add(pc)
elif name == 'CODECOPY':
address = operands[0].value
size = operands[2].value
src_pc = operands[1].source
dst_pc = operands[1].value
if src_pc is None or dst_pc is None:
raise ValueError('Error resolving CODECOPY address. pc: {:#x}, source: {:#x}'
.format(pc, operands[1].pc))
# Construct relocation table
relocate.sources[src_pc] = None
relocate.destinations[dst_pc] = None
# Resolve write address and write size, label memory
if address is not None and size is not None:
for i in range(size):
if address + i not in memory:
memory[address + i] = set()
instr.overwrite.update(memory[address + i])
memory[address + i].add(pc)
# Can not resolve write address or write size, label all possible addresses
else:
if 'all' not in memory:
memory['all'] = set()
for addr in memory:
instr.overwrite.update(memory[addr])
memory['all'].add(pc)
elif name == 'EXTCODECOPY':
address = operands[1].value
size = operands[3].value
# Resolve write address and write size, label memory
if address is not None and size is not None:
for i in range(size):
if address + i not in memory:
memory[address + i] = set()
instr.overwrite.update(memory[address + i])
memory[address + i].add(pc)
# Can not resolve write address or write size, label all possible addresses
else:
if 'all' not in memory:
memory['all'] = set()
for addr in memory:
instr.overwrite.update(memory[addr])
memory['all'].add(pc)
elif name == 'CALL':
# Start tracing executed instructions from CALL to SSTORE
if pc not in sequence:
sequence[pc] = set()
read_address = operands[3].value
read_size = operands[4].value
# Resolve read address and read size, record memory dependencies
if read_address is not None and read_size is not None:
for i in range(read_size):
if read_address + i in memory:
instr.dependence.update(memory[read_address + i])
if 'all' in memory:
instr.dependence.update(memory['all'])
# Can not resolve read address or read size, record all possible memory dependencies
else:
for addr in memory:
instr.dependence.update(memory[addr])
write_address = operands[5].value
write_size = operands[6].value
# Resolve write address and write size, label memory
if write_address is not None and write_size is not None:
for i in range(write_size):
if write_address + i not in memory:
memory[write_address + i] = set()
instr.overwrite.update(memory[write_address + i])
memory[write_address + i].add(pc)
# Can not resolve write address or write size, label all possible addresses
else:
if 'all' not in memory:
memory['all'] = set()
for addr in memory:
instr.overwrite.update(memory[addr])
memory['all'].add(pc)
stack.insert(0, OperandStackElement(pc, instr))
elif name == 'CALLCODE':
read_address = operands[3].value
read_size = operands[4].value
# Resolve read address and read size, record memory dependencies
if read_address is not None and read_size is not None:
for i in range(read_size):
if read_address + i in memory:
instr.dependence.update(memory[read_address + i])
if 'all' in memory:
instr.dependence.update(memory['all'])
# Can not resolve read address or read size, record all possible memory dependencies
else:
for addr in memory:
instr.dependence.update(memory[addr])
write_address = operands[5].value
write_size = operands[6].value
# Resolve write address and write size, label memory
if write_address is not None and write_size is not None:
for i in range(write_size):
if write_address + i not in memory:
memory[write_address + i] = set()
instr.overwrite.update(memory[write_address + i])
memory[write_address + i].add(pc)
# Can not resolve write address or write size, label all possible addresses
else:
if 'all' not in memory:
memory['all'] = set()
for addr in memory:
instr.overwrite.update(memory[addr])
memory['all'].add(pc)
stack.insert(0, OperandStackElement(pc, instr))
elif name == 'DELEGATECALL' or name == 'STATICCALL':
read_address = operands[2].value
read_size = operands[3].value
# Resolve read address and read size, record memory dependencies
if read_address is not None and read_size is not None:
for i in range(read_size):
if read_address + i in memory:
instr.dependence.update(memory[read_address + i])
if 'all' in memory:
instr.dependence.update(memory['all'])
# Can not resolve read address or read size, record all possible memory dependencies
else:
for addr in memory:
instr.dependence.update(memory[addr])
write_address = operands[4].value
write_size = operands[5].value
# Resolve write address and write size, label memory
if write_address is not None and write_size is not None:
for i in range(write_size):
if write_address + i not in memory:
memory[write_address + i] = set()
instr.overwrite.update(memory[write_address + i])
memory[write_address + i].add(pc)
# Can not resolve write address or write size, label all possible addresses
else:
if 'all' not in memory:
memory['all'] = set()
for addr in memory:
instr.overwrite.update(memory[addr])
memory['all'].add(pc)
stack.insert(0, OperandStackElement(pc, instr))
elif name == 'SLOAD':
address = operands[0].value
# Resolve read address, record storage dependencies
if address is not None:
if address in storage:
instr.dependence.update(storage[address])
if 'all' in storage:
instr.dependence.update(storage['all'])
# Can not resolve read address, record all possible storage dependencies
else:
for addr in storage:
instr.dependence.update(storage[addr])
stack.insert(0, OperandStackElement(pc, instr))
elif name == 'SSTORE':
# End tracing executed instructions from CALL to SSTORE
for off in sequence:
if (off, pc) not in trace:
trace[(off, pc)] = set()
trace[(off, pc)].update(sequence[off])
address = operands[0].value
# Resolve write address, label storage
if address is not None:
if address not in storage:
storage[address] = set()
instr.overwrite.update(storage[address])
storage[address].add(pc)
# Can not resolve write address, label all possible addresses
else:
if 'all' not in storage:
storage['all'] = set()
for addr in storage:
instr.overwrite.update(storage[addr])
storage['all'].add(pc)
else:
outs = opcodes.listing[op][2]
for i in range(outs):
stack.insert(0, OperandStackElement(pc, instr))
if len(stack) > MAX_DEPTH:
raise RuntimeError('Stack overflow. pc: {:#x}'.format(pc))
size = opcodes.operand_size(op)
pc += size + 1
if blk.next is not None:
# Add CFG edges, representing control flow dependencies between basic blocks
cfg.graph.add_edge(blk.offset, blk.next.offset, type='SEQUENTIAL')
# Update number of return values to wait
elm.num += 1
return [State(stat.next_block.next, stack, memory, storage, sequence)]
else:
# Current block is NOT revert block
return False