| # Copyright 2019 Google LLC |
| # |
| # Licensed under the Apache License, Version 2.0 (the "License"); |
| # you may not use this file except in compliance with the License. |
| # You may obtain a copy of the License at |
| # |
| # https://www.apache.org/licenses/LICENSE-2.0 |
| # |
| # Unless required by applicable law or agreed to in writing, software |
| # distributed under the License is distributed on an "AS IS" BASIS, |
| # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| # See the License for the specific language governing permissions and |
| # limitations under the License. |
| |
| """Module which adds and verifies attributes in Emboss IR. |
| |
| The main entry point is normalize_and_verify(), which adds attributes and/or |
| verifies attributes which may have been manually entered. |
| """ |
| |
| import re |
| |
| from compiler.front_end import attributes |
| from compiler.front_end import type_check |
| from compiler.util import attribute_util |
| from compiler.util import error |
| from compiler.util import ir_pb2 |
| from compiler.util import ir_util |
| from compiler.util import traverse_ir |
| |
| |
| # Default value for maximum_bits on an `enum`. |
| _DEFAULT_ENUM_MAXIMUM_BITS = 64 |
| |
| # Default value for expected_back_ends -- mostly for legacy |
| _DEFAULT_BACK_ENDS = "cpp" |
| |
| # Attribute type checkers |
| _VALID_BYTE_ORDER = attribute_util.string_from_list( |
| {"BigEndian", "LittleEndian", "Null"}) |
| _VALID_TEXT_OUTPUT = attribute_util.string_from_list({"Emit", "Skip"}) |
| |
| |
| def _valid_back_ends(attr, module_source_file): |
| if not re.match( |
| r"^(?:\s*[a-z][a-z0-9_]*\s*(?:,\s*[a-z][a-z0-9_]*\s*)*,?)?\s*$", |
| attr.value.string_constant.text): |
| return [[error.error( |
| module_source_file, |
| attr.value.source_location, |
| "Attribute '{name}' must be a comma-delimited list of back end " |
| "specifiers (like \"cpp, proto\")), not \"{value}\".".format( |
| name=attr.name.text, |
| value=attr.value.string_constant.text))]] |
| return [] |
| |
| |
| # Attributes must be the same type no matter where they occur. |
| _ATTRIBUTE_TYPES = { |
| attributes.ADDRESSABLE_UNIT_SIZE: attribute_util.INTEGER_CONSTANT, |
| attributes.BYTE_ORDER: _VALID_BYTE_ORDER, |
| attributes.ENUM_MAXIMUM_BITS: attribute_util.INTEGER_CONSTANT, |
| attributes.FIXED_SIZE: attribute_util.INTEGER_CONSTANT, |
| attributes.IS_INTEGER: attribute_util.BOOLEAN_CONSTANT, |
| attributes.IS_SIGNED: attribute_util.BOOLEAN_CONSTANT, |
| attributes.REQUIRES: attribute_util.BOOLEAN, |
| attributes.STATIC_REQUIREMENTS: attribute_util.BOOLEAN, |
| attributes.TEXT_OUTPUT: _VALID_TEXT_OUTPUT, |
| attributes.BACK_ENDS: _valid_back_ends, |
| } |
| |
| _MODULE_ATTRIBUTES = { |
| (attributes.BYTE_ORDER, True), |
| (attributes.BACK_ENDS, False), |
| } |
| _BITS_ATTRIBUTES = { |
| (attributes.FIXED_SIZE, False), |
| (attributes.REQUIRES, False), |
| } |
| _STRUCT_ATTRIBUTES = { |
| (attributes.FIXED_SIZE, False), |
| (attributes.BYTE_ORDER, True), |
| (attributes.REQUIRES, False), |
| } |
| _ENUM_ATTRIBUTES = { |
| (attributes.ENUM_MAXIMUM_BITS, False), |
| (attributes.IS_SIGNED, False), |
| } |
| _EXTERNAL_ATTRIBUTES = { |
| (attributes.ADDRESSABLE_UNIT_SIZE, False), |
| (attributes.FIXED_SIZE, False), |
| (attributes.IS_INTEGER, False), |
| (attributes.STATIC_REQUIREMENTS, False), |
| } |
| _STRUCT_PHYSICAL_FIELD_ATTRIBUTES = { |
| (attributes.BYTE_ORDER, False), |
| (attributes.REQUIRES, False), |
| (attributes.TEXT_OUTPUT, False), |
| } |
| _STRUCT_VIRTUAL_FIELD_ATTRIBUTES = { |
| (attributes.REQUIRES, False), |
| (attributes.TEXT_OUTPUT, False), |
| } |
| |
| |
| 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, |
| source_location=source_location), |
| value=attr_value, |
| source_location=source_location) |
| |
| |
| 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_string_attribute(name, value, source_location): |
| """Constructs a string Attribute with the given name and value.""" |
| attr_value = ir_pb2.AttributeValue( |
| string_constant=ir_pb2.String(text=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 _fixed_size_of_struct_or_bits(struct, unit_size): |
| """Returns size of struct in bits or None, if struct is not fixed size.""" |
| size = 0 |
| for field in struct.field: |
| if not field.HasField("location"): |
| # Virtual fields do not contribute to the physical size of the struct. |
| continue |
| field_start = ir_util.constant_value(field.location.start) |
| field_size = ir_util.constant_value(field.location.size) |
| if field_start is None or field_size is None: |
| # Technically, start + size could be constant even if start and size are |
| # not; e.g. if start == x and size == 10 - x, but we don't handle that |
| # here. |
| return None |
| # TODO(bolms): knows_own_size |
| # TODO(bolms): compute min/max sizes for variable-sized arrays. |
| field_end = field_start + field_size |
| if field_end >= size: |
| size = field_end |
| return size * unit_size |
| |
| |
| def _verify_size_attributes_on_structure(struct, type_definition, |
| source_file_name, errors): |
| """Verifies size attributes on a struct or bits.""" |
| fixed_size = _fixed_size_of_struct_or_bits(struct, |
| type_definition.addressable_unit) |
| fixed_size_attr = ir_util.get_attribute(type_definition.attribute, |
| attributes.FIXED_SIZE) |
| if not fixed_size_attr: |
| return |
| if fixed_size is None: |
| errors.append([error.error( |
| source_file_name, fixed_size_attr.source_location, |
| "Struct is marked as fixed size, but contains variable-location " |
| "fields.")]) |
| elif ir_util.constant_value(fixed_size_attr.expression) != fixed_size: |
| errors.append([error.error( |
| source_file_name, fixed_size_attr.source_location, |
| "Struct is {} bits, but is marked as {} bits.".format( |
| fixed_size, ir_util.constant_value(fixed_size_attr.expression)))]) |
| |
| |
| # TODO(bolms): remove [fixed_size]; it is superseded by $size_in_{bits,bytes} |
| def _add_missing_size_attributes_on_structure(struct, type_definition): |
| """Adds missing size attributes on a struct.""" |
| fixed_size = _fixed_size_of_struct_or_bits(struct, |
| type_definition.addressable_unit) |
| if fixed_size is None: |
| return |
| fixed_size_attr = ir_util.get_attribute(type_definition.attribute, |
| attributes.FIXED_SIZE) |
| if not fixed_size_attr: |
| # TODO(bolms): Use the offset and length of the last field as the |
| # source_location of the fixed_size attribute? |
| type_definition.attribute.extend([ |
| _construct_integer_attribute(attributes.FIXED_SIZE, fixed_size, |
| type_definition.source_location)]) |
| |
| |
| def _field_needs_byte_order(field, type_definition, ir): |
| """Returns true if the given field needs a byte_order attribute.""" |
| if ir_util.field_is_virtual(field): |
| # Virtual fields have no physical type, and thus do not need a byte order. |
| return False |
| field_type = ir_util.find_object( |
| ir_util.get_base_type(field.type).atomic_type.reference.canonical_name, |
| ir) |
| assert field_type is not None |
| assert field_type.addressable_unit != ir_pb2.TypeDefinition.NONE |
| return field_type.addressable_unit != type_definition.addressable_unit |
| |
| |
| def _field_may_have_null_byte_order(field, type_definition, ir): |
| """Returns true if "Null" is a valid byte order for the given field.""" |
| # If the field is one unit in length, then byte order does not matter. |
| if (ir_util.is_constant(field.location.size) and |
| ir_util.constant_value(field.location.size) == 1): |
| return True |
| unit = type_definition.addressable_unit |
| # Otherwise, if the field's type is either a one-unit-sized type or an array |
| # of a one-unit-sized type, then byte order does not matter. |
| if (ir_util.fixed_size_of_type_in_bits(ir_util.get_base_type(field.type), ir) |
| == unit): |
| return True |
| # In all other cases, byte order does matter. |
| return False |
| |
| |
| def _add_missing_byte_order_attribute_on_field(field, type_definition, ir, |
| defaults): |
| """Adds missing byte_order attributes to fields that need them.""" |
| if _field_needs_byte_order(field, type_definition, ir): |
| byte_order_attr = ir_util.get_attribute(field.attribute, |
| attributes.BYTE_ORDER) |
| if byte_order_attr is None: |
| if attributes.BYTE_ORDER in defaults: |
| field.attribute.extend([defaults[attributes.BYTE_ORDER]]) |
| elif _field_may_have_null_byte_order(field, type_definition, ir): |
| field.attribute.extend( |
| [_construct_string_attribute(attributes.BYTE_ORDER, "Null", |
| field.source_location)]) |
| |
| |
| def _add_missing_back_ends_to_module(module): |
| """Sets the expected_back_ends attribute for a module, if not already set.""" |
| back_ends_attr = ir_util.get_attribute(module.attribute, attributes.BACK_ENDS) |
| if back_ends_attr is None: |
| module.attribute.extend( |
| [_construct_string_attribute(attributes.BACK_ENDS, _DEFAULT_BACK_ENDS, |
| module.source_location)]) |
| |
| |
| def _gather_expected_back_ends(module): |
| """Captures the expected_back_ends attribute for `module`.""" |
| back_ends_attr = ir_util.get_attribute(module.attribute, attributes.BACK_ENDS) |
| back_ends_str = back_ends_attr.string_constant.text |
| return { |
| "expected_back_ends": {x.strip() for x in back_ends_str.split(",")} | {""} |
| } |
| |
| |
| def _add_addressable_unit_to_external(external, type_definition): |
| """Sets the addressable_unit field for an external TypeDefinition.""" |
| # Strictly speaking, addressable_unit isn't an "attribute," but it's close |
| # enough that it makes sense to handle it with attributes. |
| del external # Unused. |
| size = ir_util.get_integer_attribute(type_definition.attribute, |
| attributes.ADDRESSABLE_UNIT_SIZE) |
| if size == 1: |
| type_definition.addressable_unit = ir_pb2.TypeDefinition.BIT |
| elif size == 8: |
| type_definition.addressable_unit = ir_pb2.TypeDefinition.BYTE |
| # If the addressable_unit_size is not in (1, 8), it will be caught by |
| # _verify_addressable_unit_attribute_on_external, below. |
| |
| |
| def _add_missing_width_and_sign_attributes_on_enum(enum, type_definition): |
| """Sets the maximum_bits and is_signed attributes for an enum, if needed.""" |
| max_bits_attr = ir_util.get_integer_attribute(type_definition.attribute, |
| attributes.ENUM_MAXIMUM_BITS) |
| if max_bits_attr is None: |
| type_definition.attribute.extend([ |
| _construct_integer_attribute(attributes.ENUM_MAXIMUM_BITS, |
| _DEFAULT_ENUM_MAXIMUM_BITS, |
| type_definition.source_location)]) |
| signed_attr = ir_util.get_boolean_attribute(type_definition.attribute, |
| attributes.IS_SIGNED) |
| if signed_attr is None: |
| for value in enum.value: |
| numeric_value = ir_util.constant_value(value.value) |
| if numeric_value < 0: |
| is_signed = True |
| break |
| else: |
| is_signed = False |
| type_definition.attribute.extend([ |
| _construct_boolean_attribute(attributes.IS_SIGNED, is_signed, |
| type_definition.source_location)]) |
| |
| |
| def _verify_byte_order_attribute_on_field(field, type_definition, |
| source_file_name, ir, errors): |
| """Verifies the byte_order attribute on the given field.""" |
| byte_order_attr = ir_util.get_attribute(field.attribute, |
| attributes.BYTE_ORDER) |
| field_needs_byte_order = _field_needs_byte_order(field, type_definition, ir) |
| if byte_order_attr and not field_needs_byte_order: |
| errors.append([error.error( |
| source_file_name, byte_order_attr.source_location, |
| "Attribute 'byte_order' not allowed on field which is not byte order " |
| "dependent.")]) |
| if not byte_order_attr and field_needs_byte_order: |
| errors.append([error.error( |
| source_file_name, field.source_location, |
| "Attribute 'byte_order' required on field which is byte order " |
| "dependent.")]) |
| if (byte_order_attr and byte_order_attr.string_constant.text == "Null" and |
| not _field_may_have_null_byte_order(field, type_definition, ir)): |
| errors.append([error.error( |
| source_file_name, byte_order_attr.source_location, |
| "Attribute 'byte_order' may only be 'Null' for one-byte fields.")]) |
| |
| |
| def _verify_requires_attribute_on_field(field, source_file_name, ir, errors): |
| """Verifies that [requires] is valid on the given field.""" |
| requires_attr = ir_util.get_attribute(field.attribute, attributes.REQUIRES) |
| if not requires_attr: |
| return |
| if ir_util.field_is_virtual(field): |
| field_expression_type = field.read_transform.type |
| else: |
| if not field.type.HasField("atomic_type"): |
| errors.append([ |
| error.error(source_file_name, requires_attr.source_location, |
| "Attribute 'requires' is only allowed on integer, " |
| "enumeration, or boolean fields, not arrays."), |
| error.note(source_file_name, field.type.source_location, |
| "Field type."), |
| ]) |
| return |
| field_type = ir_util.find_object(field.type.atomic_type.reference, ir) |
| assert field_type, "Field type should be non-None after name resolution." |
| field_expression_type = ( |
| type_check.unbounded_expression_type_for_physical_type(field_type)) |
| if field_expression_type.WhichOneof("type") not in ( |
| "integer", "enumeration", "boolean"): |
| errors.append([error.error( |
| source_file_name, requires_attr.source_location, |
| "Attribute 'requires' is only allowed on integer, enumeration, or " |
| "boolean fields.")]) |
| |
| |
| def _verify_addressable_unit_attribute_on_external(external, type_definition, |
| source_file_name, errors): |
| """Verifies the addressable_unit_size attribute on an external.""" |
| del external # Unused. |
| addressable_unit_size_attr = ir_util.get_integer_attribute( |
| type_definition.attribute, attributes.ADDRESSABLE_UNIT_SIZE) |
| if addressable_unit_size_attr is None: |
| errors.append([error.error( |
| source_file_name, type_definition.source_location, |
| "Expected '{}' attribute for external type.".format( |
| attributes.ADDRESSABLE_UNIT_SIZE))]) |
| elif addressable_unit_size_attr not in (1, 8): |
| errors.append([ |
| error.error(source_file_name, type_definition.source_location, |
| "Only values '1' (bit) and '8' (byte) are allowed for the " |
| "'{}' attribute".format(attributes.ADDRESSABLE_UNIT_SIZE)) |
| ]) |
| |
| |
| def _verify_width_attribute_on_enum(enum, type_definition, source_file_name, |
| errors): |
| """Verifies the maximum_bits attribute for an enum TypeDefinition.""" |
| max_bits_value = ir_util.get_integer_attribute(type_definition.attribute, |
| attributes.ENUM_MAXIMUM_BITS) |
| # The attribute should already have been defaulted, if not originally present. |
| assert max_bits_value is not None, "maximum_bits not set" |
| if max_bits_value > 64 or max_bits_value < 1: |
| max_bits_attr = ir_util.get_attribute(type_definition.attribute, |
| attributes.ENUM_MAXIMUM_BITS) |
| errors.append([ |
| error.error(source_file_name, max_bits_attr.source_location, |
| "'maximum_bits' on an 'enum' must be between 1 and 64.") |
| ]) |
| |
| |
| def _gather_default_attributes(obj, defaults): |
| defaults = defaults.copy() |
| for attr in obj.attribute: |
| if attr.is_default: |
| defaulted_attr = ir_pb2.Attribute() |
| defaulted_attr.CopyFrom(attr) |
| defaulted_attr.is_default = False |
| defaults[attr.name.text] = defaulted_attr |
| return {"defaults": defaults} |
| |
| |
| def _add_missing_attributes_on_ir(ir): |
| """Adds missing attributes in a complete IR.""" |
| traverse_ir.fast_traverse_ir_top_down( |
| ir, [ir_pb2.Module], _add_missing_back_ends_to_module) |
| traverse_ir.fast_traverse_ir_top_down( |
| ir, [ir_pb2.External], _add_addressable_unit_to_external) |
| traverse_ir.fast_traverse_ir_top_down( |
| ir, [ir_pb2.Enum], _add_missing_width_and_sign_attributes_on_enum) |
| traverse_ir.fast_traverse_ir_top_down( |
| ir, [ir_pb2.Structure], _add_missing_size_attributes_on_structure, |
| incidental_actions={ |
| ir_pb2.Module: _gather_default_attributes, |
| ir_pb2.TypeDefinition: _gather_default_attributes, |
| ir_pb2.Field: _gather_default_attributes, |
| }, |
| parameters={"defaults": {}}) |
| traverse_ir.fast_traverse_ir_top_down( |
| ir, [ir_pb2.Field], _add_missing_byte_order_attribute_on_field, |
| incidental_actions={ |
| ir_pb2.Module: _gather_default_attributes, |
| ir_pb2.TypeDefinition: _gather_default_attributes, |
| ir_pb2.Field: _gather_default_attributes, |
| }, |
| parameters={"defaults": {}}) |
| return [] |
| |
| |
| def _verify_field_attributes(field, type_definition, source_file_name, ir, |
| errors): |
| _verify_byte_order_attribute_on_field(field, type_definition, |
| source_file_name, ir, errors) |
| _verify_requires_attribute_on_field(field, source_file_name, ir, errors) |
| |
| |
| def _verify_back_end_attributes(attribute, expected_back_ends, source_file_name, |
| ir, errors): |
| back_end_text = attribute.back_end.text |
| if back_end_text not in expected_back_ends: |
| expected_back_ends_for_error = expected_back_ends - {""} |
| errors.append([error.error( |
| source_file_name, attribute.back_end.source_location, |
| "Back end specifier '{back_end}' does not match any expected back end " |
| "specifier for this file: '{expected_back_ends}'. Add or update the " |
| "'[expected_back_ends: \"{new_expected_back_ends}\"]' attribute at the " |
| "file level if this back end specifier is intentional.".format( |
| back_end=attribute.back_end.text, |
| expected_back_ends="', '".join( |
| sorted(expected_back_ends_for_error)), |
| new_expected_back_ends=", ".join( |
| sorted(expected_back_ends_for_error | {back_end_text})), |
| ))]) |
| |
| |
| def _verify_attributes_on_ir(ir): |
| """Verifies attributes in a complete IR.""" |
| errors = [] |
| traverse_ir.fast_traverse_ir_top_down( |
| ir, [ir_pb2.Attribute], _verify_back_end_attributes, |
| incidental_actions={ |
| ir_pb2.Module: _gather_expected_back_ends, |
| }, |
| parameters={"errors": errors}) |
| traverse_ir.fast_traverse_ir_top_down( |
| ir, [ir_pb2.Structure], _verify_size_attributes_on_structure, |
| parameters={"errors": errors}) |
| traverse_ir.fast_traverse_ir_top_down( |
| ir, [ir_pb2.Enum], _verify_width_attribute_on_enum, |
| parameters={"errors": errors}) |
| traverse_ir.fast_traverse_ir_top_down( |
| ir, [ir_pb2.External], _verify_addressable_unit_attribute_on_external, |
| parameters={"errors": errors}) |
| traverse_ir.fast_traverse_ir_top_down( |
| ir, [ir_pb2.Field], _verify_field_attributes, |
| parameters={"errors": errors}) |
| return errors |
| |
| |
| def normalize_and_verify(ir): |
| """Performs various normalizations and verifications on ir. |
| |
| Checks for duplicate attributes. |
| |
| Adds fixed_size_in_bits and addressable_unit_size attributes to types when |
| they are missing, and checks their correctness when they are not missing. |
| |
| Arguments: |
| ir: The IR object to normalize. |
| |
| Returns: |
| A list of validation errors, or an empty list if no errors were encountered. |
| """ |
| errors = attribute_util.check_attributes_in_ir( |
| ir, |
| types=_ATTRIBUTE_TYPES, |
| module_attributes=_MODULE_ATTRIBUTES, |
| struct_attributes=_STRUCT_ATTRIBUTES, |
| bits_attributes=_BITS_ATTRIBUTES, |
| enum_attributes=_ENUM_ATTRIBUTES, |
| external_attributes=_EXTERNAL_ATTRIBUTES, |
| structure_virtual_field_attributes=_STRUCT_VIRTUAL_FIELD_ATTRIBUTES, |
| structure_physical_field_attributes=_STRUCT_PHYSICAL_FIELD_ATTRIBUTES) |
| if errors: |
| return errors |
| _add_missing_attributes_on_ir(ir) |
| return _verify_attributes_on_ir(ir) |
