def test_division_by_zero(prime):
simplifier = ExpressionSimplifier(prime)
with pytest.raises(SimplifierError, match='Division by zero'):
simplifier.visit(parse_expr('fp / 0'))
with pytest.raises(SimplifierError, match='Division by zero'):
simplifier.visit(parse_expr('5 / 0'))
if prime is not None:
with pytest.raises(SimplifierError, match='Division by zero'):
simplifier.visit(parse_expr(f'fp / {prime}'))
def test_modulo():
PRIME = 19
simplifier = ExpressionSimplifier(PRIME)
# Check that the range is (-PRIME/2, PRIME/2).
assert simplifier.visit(parse_expr('-9')).format() == '-9'
assert simplifier.visit(parse_expr('-10')).format() == '9'
assert simplifier.visit(parse_expr('9')).format() == '9'
assert simplifier.visit(parse_expr('10')).format() == '-9'
# Check value which is bigger than PRIME.
assert simplifier.visit(parse_expr('20')).format() == '1'
# Check operators.
assert simplifier.visit(parse_expr('10 + 10')).format() == '1'
assert simplifier.visit(parse_expr('10 - 30')).format() == '-1'
assert simplifier.visit(parse_expr('10 * 10')).format() == '5'
assert simplifier.visit(parse_expr('2 / 3')).format() == '7'
def test_rotation(prime):
simplifier = ExpressionSimplifier(prime)
assert simplifier.visit(parse_expr('(fp + 10) + 1')).format() == 'fp + 11'
assert simplifier.visit(parse_expr('(fp + 10) - 1')).format() == 'fp + 9'
assert simplifier.visit(
parse_expr('(fp - 10) + 1')).format() == 'fp + (-9)'
assert simplifier.visit(
parse_expr('(fp - 10) - 1')).format() == 'fp + (-11)'
assert simplifier.visit(parse_expr('(10 + fp) - 1')).format() == 'fp + 9'
assert simplifier.visit(parse_expr('10 + (fp - 1)')).format() == 'fp + 9'
assert simplifier.visit(parse_expr('10 + (1 + fp)')).format() == 'fp + 11'
assert simplifier.visit(
parse_expr('10 + (1 + fp) + 100')).format() == 'fp + 111'
assert simplifier.visit(
parse_expr('10 + (1 + (fp + 100))')).format() == 'fp + 111'
def test_operator_precedence():
code = '(5 + 2) - (3 - 9) * (7 + (-8)) - 10 * (-2) * 5 + (((7)))'
expr = parse_expr(code)
# Test formatting.
assert expr.format() == code
# Compute the value of expr from the tree and compare it with the correct value.
PRIME = 3 * 2**30 + 1
simplified_expr = ExpressionSimplifier(PRIME).visit(expr)
assert isinstance(simplified_expr, ExprConst)
assert simplified_expr.val == eval(code)
def test_div_expr():
assert parse_expr(
'[ap]/[fp]/3/[ap+1]').format() == '[ap] / [fp] / 3 / [ap + 1]'
code = '120 / 2 / 3 / 4'
expr = parse_expr(code)
# Compute the value of expr from the tree and compare it with the correct value.
PRIME = 3 * 2**30 + 1
simplified_expr = ExpressionSimplifier(PRIME).visit(expr)
assert isinstance(simplified_expr, ExprConst)
assert simplified_expr.val == 5
def test_simplifier(prime):
assignments = {'x': 10, 'y': 3, 'z': -2, 'w': -60}
simplifier = ExpressionSimplifier(prime)
simplify = lambda expr: simplifier.visit(
substitute_identifiers(expr, lambda var: assignments[var.name]))
assert simplify(parse_expr('fp + x * (y + -1)')).format() == 'fp + 20'
assert simplify(parse_expr('[fp + x] + [ap - (-z)]')).format() == \
'[fp + 10] + [ap + (-2)]'
assert simplify(parse_expr('fp + x - y')).format() == 'fp + 7'
assert simplify(parse_expr('[1 + fp + 5]')).format() == '[fp + 6]'
assert simplify(parse_expr('[fp] - 3')).format() == '[fp] + (-3)'
if prime is not None:
assert simplify(parse_expr('fp * (x - 1) / y')).format() == 'fp * 3'
assert simplify(parse_expr('fp * w / x / y / z')).format() == 'fp'
else:
assert simplify(
parse_expr('fp * (x - 1) / y')).format() == 'fp * 9 / 3'
assert simplify(parse_expr('fp * w / x / y / z')).format() == \
'fp * (-60) / 10 / 3 / (-2)'
assert simplify(parse_expr('fp * 1')).format() == 'fp'
assert simplify(parse_expr('1 * fp')).format() == 'fp'
def converge(
self, reference_manager: ReferenceManager, other: 'FlowTrackingData',
group_alloc: Callable):
if not isinstance(other, FlowTrackingDataActual):
return other.converge(reference_manager, self, group_alloc)
new_ap_tracking = self.ap_tracking.converge(other.ap_tracking, group_alloc)
simplifier = ExpressionSimplifier()
# Allow different references from different branches to unite if they have the same name
# and the same expression at the converged ap_tracking.
reference_ids = {}
for name, ref_id in self.reference_ids.items():
other_ref_id = other.reference_ids.get(name)
if other_ref_id is None:
continue
reference = reference_manager.get_ref(ref_id)
other_ref = reference_manager.get_ref(other_ref_id)
try:
ref_expr = reference.eval(self.ap_tracking)
if simplifier.visit(ref_expr) == \
simplifier.visit(other_ref.eval(other.ap_tracking)):
# Same expression.
if self.ap_tracking != new_ap_tracking:
# Create a new reference on the new ap tracking.
new_reference = Reference(
pc=reference.pc,
value=ref_expr,
ap_tracking_data=new_ap_tracking,
)
ref_id = reference_manager.get_id(new_reference)
reference_ids[name] = ref_id
except FlowTrackingError:
pass
return FlowTrackingDataActual(
ap_tracking=new_ap_tracking,
reference_ids=reference_ids,
)
def test_pow(prime):
simplifier = ExpressionSimplifier(prime)
assert simplifier.visit(parse_expr('4 ** 3 ** 2')).format() == '262144'
if prime is not None:
# Make sure the exponent is not computed modulo prime (if it were,
# the result would have been 1).
assert simplifier.visit(
parse_expr('(3 * 2**30 + 4) ** (3 * 2**30 + 1)')).format() == '3'
with pytest.raises(
SimplifierError,
match='Power is not supported with a negative exponent'):
simplifier.visit(parse_expr('2 ** (-1)'))
def visit_ExprSubscript(
self, expr: ExprSubscript) -> Tuple[Expression, CairoType]:
inner_expr, inner_type = self.visit(expr.expr)
offset_expr, offset_type = self.visit(expr.offset)
if isinstance(inner_type, TypeTuple):
self.verify_offset_is_felt(offset_type, offset_expr.location)
offset_expr = ExpressionSimplifier().visit(offset_expr)
if not isinstance(offset_expr, ExprConst):
raise CairoTypeError(
'Subscript-operator for tuples supports only constant offsets, found '
f"'{type(offset_expr).__name__}'.",
location=offset_expr.location)
offset_value = offset_expr.val
tuple_len = len(inner_type.members)
if not 0 <= offset_value < tuple_len:
raise CairoTypeError(
f'Tuple index {offset_value} is out of range [0, {tuple_len}).',
location=expr.location)
item_type = inner_type.members[offset_value]
if isinstance(inner_expr, ExprTuple):
assert len(inner_expr.members.args) == tuple_len
return (
# Take the inner item, but keep the original expression's location.
dataclasses.replace(
inner_expr.members.args[offset_value].expr,
location=expr.location),
item_type)
elif isinstance(inner_expr, ExprDeref):
# Handles pointers cast as tuples*, e.g. `[cast(ap, (felt, felt)*][0]`.
addr = inner_expr.addr
offset_in_felts = ExprConst(val=sum(
map(self.get_size, inner_type.members[:offset_value])),
location=offset_expr.location)
addr_with_offset = ExprOperator(a=addr,
op='+',
b=offset_in_felts,
location=expr.location)
return ExprDeref(addr=addr_with_offset,
location=expr.location), item_type
else:
raise CairoTypeError(
'Unexpected expression typed as TypeTuple. Expected ExprTuple or ExprDeref, '
f"found '{type(inner_expr).__name__}'.",
location=expr.location)
elif isinstance(inner_type, TypePointer):
self.verify_offset_is_felt(offset_type, offset_expr.location)
try:
# If pointed type is struct, get_size could throw IdentifierErrors. We catch and
# convert them to CairoTypeErrors.
element_size = self.get_size(inner_type.pointee)
except Exception as exc:
raise CairoTypeError(str(exc), location=expr.location)
element_size_expr = ExprConst(val=element_size,
location=expr.location)
modified_offset_expr = ExprOperator(a=offset_expr,
op='*',
b=element_size_expr,
location=expr.location)
simplified_expr = ExprDeref(addr=ExprOperator(
a=inner_expr,
op='+',
b=modified_offset_expr,
location=expr.location),
location=expr.location)
return simplified_expr, inner_type.pointee
else:
raise CairoTypeError(
'Cannot apply subscript-operator to non-pointer, non-tuple type '
f"'{inner_type.format()}'.",
location=expr.location)