def rewrite_free_ptr(block):
for i, instruction in enumerate(block.get_instructions()):
opcode = instruction.opcode
if opcode == "MLOAD" and \
instruction.reads[0] == 64:
new_instruction = MoveInstruction("MOVE", ["$m"],
instruction.writes,
instruction.address)
block.set_instruction(i, new_instruction)
elif opcode == "MSTORE" and \
instruction.reads[0] == 64:
new_instruction = MoveInstruction("MOVE", [instruction.reads[1]],
["$m"], instruction.address)
block.set_instruction(i, new_instruction)
def __fold_constant(i, instruction, block):
opcode = instruction.opcode
constants = instruction.get_constants()
if not constants:
return
inputs = [opcode] + constants
writes = instruction.writes
address = instruction.address
if opcode in bin_ops:
try:
value = execute_binop(inputs)
except ZeroDivisionError:
return
new_instruction = MoveInstruction("MOVE", [value], writes, address)
block.set_instruction(i, new_instruction)
elif opcode in mono_ops:
value = execute_monop(inputs)
new_instruction = MoveInstruction("MOVE", [value], writes, address)
block.set_instruction(i, new_instruction)
def __rewrite_move(i, instruction, block):
opcode = instruction.opcode
reads = instruction.reads
writes = instruction.writes
address = instruction.address
if opcode == "DIV" and reads[1] == 1:
new_instruction = MoveInstruction("MOVE", [reads[0]], writes, address)
block.set_instruction(i, new_instruction)
elif opcode == "ADD" and reads[0] == 0:
new_instruction = MoveInstruction("MOVE", [reads[1]], writes, address)
block.set_instruction(i, new_instruction)
elif opcode == "MUL" and reads[0] == 1:
new_instruction = MoveInstruction("MOVE", [reads[1]], writes, address)
block.set_instruction(i, new_instruction)
elif opcode == "AND" and reads[0] == WORD_MASK:
new_instruction = MoveInstruction("MOVE", [reads[1]], writes, address)
block.set_instruction(i, new_instruction)
elif opcode == "SUB" and reads[0] == reads[1]:
new_instruction = MoveInstruction("MOVE", [0], writes, address)
block.set_instruction(i, new_instruction)
def __remove_address_mask(i, instruction_0, instruction_1, block):
if instruction_0.opcode not in {"CALLER", "ADDRESS"} or \
instruction_1.opcode != "AND":
return
w_0 = instruction_0.writes[0]
w_1 = instruction_1.writes[0]
reads_1 = instruction_1.reads
if reads_1[0] != ADDRESS_MASK or reads_1[1] != w_0:
return
address = instruction_1.address
instruction_1 = MoveInstruction("MOVE", [w_0], [w_1], address)
block.set_instruction(i, instruction_1)