def unbounded_expression_type_for_physical_type(type_definition):
"""Gets the ExpressionType for a field of the given TypeDefinition.
Arguments:
type_definition: an ir_pb2.TypeDefinition.
Returns:
An ir_pb2.ExpressionType with the corresponding expression type filled in:
for example, [prelude].UInt will result in an ExpressionType with the
`integer` field filled in.
The returned ExpressionType will not have any bounds set.
"""
# TODO(bolms): Add a `[value_type]` attribute for `external`s.
if ir_util.get_boolean_attribute(type_definition.attribute,
attributes.IS_INTEGER):
return ir_pb2.ExpressionType(integer=ir_pb2.IntegerType())
elif tuple(type_definition.name.canonical_name.object_path) == ("Flag", ):
# This is a hack: the Flag type should say that it is a boolean.
return ir_pb2.ExpressionType(boolean=ir_pb2.BooleanType())
elif type_definition.HasField("enumeration"):
return ir_pb2.ExpressionType(enumeration=ir_pb2.EnumType(
name=ir_pb2.Reference(
canonical_name=type_definition.name.canonical_name)))
else:
return ir_pb2.ExpressionType(opaque=ir_pb2.OpaqueType())
def test_is_constant_enumeration_type(self):
self.assertFalse(
ir_util.is_constant_type(
ir_pb2.ExpressionType(enumeration=ir_pb2.EnumType())))
self.assertTrue(
ir_util.is_constant_type(
ir_pb2.ExpressionType(enumeration=ir_pb2.EnumType(value="0"))))
def test_is_constant_boolean_type(self):
self.assertFalse(
ir_util.is_constant_type(
ir_pb2.ExpressionType(boolean=ir_pb2.BooleanType())))
self.assertTrue(
ir_util.is_constant_type(
ir_pb2.ExpressionType(boolean=ir_pb2.BooleanType(value=True))))
self.assertTrue(
ir_util.is_constant_type(
ir_pb2.ExpressionType(boolean=ir_pb2.BooleanType(
value=False))))
def test_is_constant_integer_type(self):
self.assertFalse(
ir_util.is_constant_type(
ir_pb2.ExpressionType(
integer=ir_pb2.IntegerType(modulus="10",
modular_value="5",
minimum_value="-5",
maximum_value="15"))))
self.assertTrue(
ir_util.is_constant_type(
ir_pb2.ExpressionType(
integer=ir_pb2.IntegerType(modulus="infinity",
modular_value="5",
minimum_value="5",
maximum_value="5"))))
def test_is_constant_enum(self):
self.assertTrue(
ir_util.is_constant(
ir_pb2.Expression(
constant_reference=ir_pb2.Reference(),
type=ir_pb2.ExpressionType(enumeration=ir_pb2.EnumType(
value="12")))))
def test_constant_value_of_boolean_reference(self):
self.assertTrue(
ir_util.constant_value(
ir_pb2.Expression(
constant_reference=ir_pb2.Reference(),
type=ir_pb2.ExpressionType(boolean=ir_pb2.BooleanType(
value=True)))))
def test_constant_value_of_integer_reference(self):
self.assertEqual(
12,
ir_util.constant_value(
ir_pb2.Expression(
constant_reference=ir_pb2.Reference(),
type=ir_pb2.ExpressionType(integer=ir_pb2.IntegerType(
modulus="infinity", modular_value="12")))))
def test_constant_value_of_enum(self):
self.assertEqual(
12,
ir_util.constant_value(
ir_pb2.Expression(
constant_reference=ir_pb2.Reference(),
type=ir_pb2.ExpressionType(enumeration=ir_pb2.EnumType(
value="12")))))
def _construct_boolean_attribute(name, value, source_location):
"""Constructs a boolean Attribute with the given name and value."""
attr_value = ir_pb2.AttributeValue(
expression=ir_pb2.Expression(
boolean_constant=ir_pb2.BooleanConstant(
value=value, source_location=source_location),
type=ir_pb2.ExpressionType(boolean=ir_pb2.BooleanType(value=value)),
source_location=source_location),
source_location=source_location)
return ir_pb2.Attribute(name=ir_pb2.Word(text=name,
source_location=source_location),
value=attr_value,
source_location=source_location)
def _construct_integer_attribute(name, value, source_location):
"""Constructs an integer Attribute with the given name and value."""
attr_value = ir_pb2.AttributeValue(
expression=ir_pb2.Expression(
constant=ir_pb2.NumericConstant(value=str(value),
source_location=source_location),
type=ir_pb2.ExpressionType(
integer=ir_pb2.IntegerType(modular_value=str(value),
modulus="infinity",
minimum_value=str(value),
maximum_value=str(value))),
source_location=source_location),
source_location=source_location)
return ir_pb2.Attribute(name=ir_pb2.Word(text=name),
value=attr_value,
source_location=source_location)
def test_is_constant_opaque_type(self):
self.assertFalse(
ir_util.is_constant_type(
ir_pb2.ExpressionType(opaque=ir_pb2.OpaqueType())))
def test_get_integer_attribute(self):
type_def = ir_pb2.TypeDefinition(attribute=[
ir_pb2.Attribute(value=ir_pb2.AttributeValue(
expression=ir_pb2.Expression(type=ir_pb2.ExpressionType(
integer=ir_pb2.IntegerType()))),
name=ir_pb2.Word(text="phil")),
ir_pb2.Attribute(value=ir_pb2.AttributeValue(
expression=ir_pb2.Expression(
constant=ir_pb2.NumericConstant(value="20"),
type=ir_pb2.ExpressionType(integer=ir_pb2.IntegerType(
modular_value="20", modulus="infinity")))),
name=ir_pb2.Word(text="bob"),
is_default=True),
ir_pb2.Attribute(value=ir_pb2.AttributeValue(
expression=ir_pb2.Expression(
constant=ir_pb2.NumericConstant(value="10"),
type=ir_pb2.ExpressionType(integer=ir_pb2.IntegerType(
modular_value="10", modulus="infinity")))),
name=ir_pb2.Word(text="bob")),
ir_pb2.Attribute(value=ir_pb2.AttributeValue(
expression=ir_pb2.Expression(
constant=ir_pb2.NumericConstant(value="5"),
type=ir_pb2.ExpressionType(integer=ir_pb2.IntegerType(
modular_value="5", modulus="infinity")))),
name=ir_pb2.Word(text="bob2")),
ir_pb2.Attribute(value=ir_pb2.AttributeValue(
expression=ir_pb2.Expression(
constant=ir_pb2.NumericConstant(value="0"),
type=ir_pb2.ExpressionType(integer=ir_pb2.IntegerType(
modular_value="0", modulus="infinity")))),
name=ir_pb2.Word(text="bob2"),
is_default=True),
ir_pb2.Attribute(value=ir_pb2.AttributeValue(
expression=ir_pb2.Expression(
constant=ir_pb2.NumericConstant(value="30"),
type=ir_pb2.ExpressionType(integer=ir_pb2.IntegerType(
modular_value="30", modulus="infinity")))),
name=ir_pb2.Word(text="bob3"),
is_default=True),
ir_pb2.Attribute(value=ir_pb2.AttributeValue(
expression=ir_pb2.Expression(function=ir_pb2.Function(
function=ir_pb2.Function.ADDITION,
args=[
ir_pb2.Expression(
constant=ir_pb2.NumericConstant(value="100"),
type=ir_pb2.ExpressionType(
integer=ir_pb2.IntegerType(
modular_value="100", modulus="infinity"))),
ir_pb2.Expression(
constant=ir_pb2.NumericConstant(value="100"),
type=ir_pb2.ExpressionType(
integer=ir_pb2.IntegerType(
modular_value="100", modulus="infinity")))
]),
type=ir_pb2.ExpressionType(
integer=ir_pb2.IntegerType(
modular_value="200",
modulus="infinity")))),
name=ir_pb2.Word(text="bob4")),
ir_pb2.Attribute(value=ir_pb2.AttributeValue(
expression=ir_pb2.Expression(
constant=ir_pb2.NumericConstant(value="40"),
type=ir_pb2.ExpressionType(integer=ir_pb2.IntegerType(
modular_value="40", modulus="infinity")))),
name=ir_pb2.Word()),
])
self.assertEqual(
10, ir_util.get_integer_attribute(type_def.attribute, "bob"))
self.assertEqual(
5, ir_util.get_integer_attribute(type_def.attribute, "bob2"))
self.assertIsNone(
ir_util.get_integer_attribute(type_def.attribute, "Bob"))
self.assertEqual(
10,
ir_util.get_integer_attribute(type_def.attribute,
"Bob",
default_value=10))
self.assertIsNone(
ir_util.get_integer_attribute(type_def.attribute, "bob3"))
self.assertEqual(
200, ir_util.get_integer_attribute(type_def.attribute, "bob4"))
def _invert_expression(expression, ir):
"""For the given expression, searches for an algebraic inverse expression.
That is, it takes the notional equation:
$logical_value = expression
and, if there is exactly one `field_reference` in `expression`, it will
attempt to solve the equation for that field. For example, if the expression
is `x + 1`, it will iteratively transform:
$logical_value = x + 1
$logical_value - 1 = x + 1 - 1
$logical_value - 1 = x
and finally return `x` and `$logical_value - 1`.
The purpose of this transformation is to find an assignment statement that can
be used to write back through certain virtual fields. E.g., given:
struct Foo:
0 [+1] UInt raw_value
let actual_value = raw_value + 100
it should be possible to write a value to the `actual_value` field, and have
it set `raw_value` to the appropriate value.
Arguments:
expression: an ir_pb2.Expression to be inverted.
ir: the full IR, for looking up symbols.
Returns:
(field_reference, inverse_expression) if expression can be inverted,
otherwise None.
"""
reference_path = _find_field_reference_path(expression)
if reference_path is None:
return None
subexpression = expression
result = ir_pb2.Expression(
builtin_reference=ir_pb2.Reference(
canonical_name=ir_pb2.CanonicalName(
module_file="",
object_path=["$logical_value"]
),
source_name=[ir_pb2.Word(
text="$logical_value",
source_location=ir_pb2.Location(is_synthetic=True)
)],
source_location=ir_pb2.Location(is_synthetic=True)
),
type=expression.type,
source_location=ir_pb2.Location(is_synthetic=True)
)
# This loop essentially starts with:
#
# f(g(x)) == $logical_value
#
# and ends with
#
# x == g_inv(f_inv($logical_value))
#
# At each step, `subexpression` has one layer removed, and `result` has a
# corresponding inverse function applied. So, for example, it might start
# with:
#
# 2 + ((3 - x) - 10) == $logical_value
#
# On each iteration, `subexpression` and `result` will become:
#
# (3 - x) - 10 == $logical_value - 2 [subtract 2 from both sides]
# (3 - x) == ($logical_value - 2) + 10 [add 10 to both sides]
# x == 3 - (($logical_value - 2) + 10) [subtract both sides from 3]
#
# This is an extremely limited algebraic solver, but it covers common-enough
# cases.
#
# Note that any equation that can be solved here becomes part of Emboss's
# contract, forever, so be conservative in expanding its solving capabilities!
for index in reference_path:
if subexpression.function.function == ir_pb2.Function.ADDITION:
result = ir_pb2.Expression(
function=ir_pb2.Function(
function=ir_pb2.Function.SUBTRACTION,
args=[
result,
subexpression.function.args[1 - index],
]
),
type=ir_pb2.ExpressionType(integer=ir_pb2.IntegerType())
)
elif subexpression.function.function == ir_pb2.Function.SUBTRACTION:
if index == 0:
result = ir_pb2.Expression(
function=ir_pb2.Function(
function=ir_pb2.Function.ADDITION,
args=[
result,
subexpression.function.args[1],
]
),
type=ir_pb2.ExpressionType(integer=ir_pb2.IntegerType())
)
else:
result = ir_pb2.Expression(
function=ir_pb2.Function(
function=ir_pb2.Function.SUBTRACTION,
args=[
subexpression.function.args[0],
result,
]
),
type=ir_pb2.ExpressionType(integer=ir_pb2.IntegerType())
)
else:
return None
subexpression = subexpression.function.args[index]
expression_bounds.compute_constraints_of_expression(result, ir)
return subexpression, result
