327 lines
12 KiB
Python
327 lines
12 KiB
Python
# Copyright 2015 The Rust Project Developers. See the COPYRIGHT
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# file at the top-level directory of this distribution and at
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# http://rust-lang.org/COPYRIGHT.
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#
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# Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
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# http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
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# <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
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# option. This file may not be copied, modified, or distributed
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# except according to those terms.
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"""
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This module provides an abstraction layer over common Rust pretty printing
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functionality needed by both GDB and LLDB.
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"""
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import re
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# Type codes that indicate the kind of type as it appears in DWARF debug
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# information. This code alone is not sufficient to determine the Rust type.
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# For example structs, tuples, fat pointers, or enum variants will all have
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# DWARF_TYPE_CODE_STRUCT.
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DWARF_TYPE_CODE_STRUCT = 1
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DWARF_TYPE_CODE_UNION = 2
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DWARF_TYPE_CODE_PTR = 3
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DWARF_TYPE_CODE_ARRAY = 4
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DWARF_TYPE_CODE_ENUM = 5
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# These constants specify the most specific kind of type that could be
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# determined for a given value.
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TYPE_KIND_UNKNOWN = -1
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TYPE_KIND_EMPTY = 0
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TYPE_KIND_SLICE = 1
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TYPE_KIND_REGULAR_STRUCT = 2
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TYPE_KIND_TUPLE = 3
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TYPE_KIND_TUPLE_STRUCT = 4
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TYPE_KIND_CSTYLE_VARIANT = 5
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TYPE_KIND_TUPLE_VARIANT = 6
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TYPE_KIND_STRUCT_VARIANT = 7
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TYPE_KIND_STR_SLICE = 8
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TYPE_KIND_STD_VEC = 9
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TYPE_KIND_STD_STRING = 10
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TYPE_KIND_REGULAR_ENUM = 11
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TYPE_KIND_COMPRESSED_ENUM = 12
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TYPE_KIND_SINGLETON_ENUM = 13
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TYPE_KIND_CSTYLE_ENUM = 14
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TYPE_KIND_PTR = 15
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TYPE_KIND_FIXED_SIZE_VEC = 16
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ENCODED_ENUM_PREFIX = "RUST$ENCODED$ENUM$"
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ENUM_DISR_FIELD_NAME = "RUST$ENUM$DISR"
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# Slice related constants
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SLICE_FIELD_NAME_DATA_PTR = "data_ptr"
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SLICE_FIELD_NAME_LENGTH = "length"
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SLICE_FIELD_NAMES = [SLICE_FIELD_NAME_DATA_PTR, SLICE_FIELD_NAME_LENGTH]
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# std::Vec<> related constants
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STD_VEC_FIELD_NAME_LENGTH = "len"
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STD_VEC_FIELD_NAME_BUF = "buf"
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STD_VEC_FIELD_NAMES = [STD_VEC_FIELD_NAME_BUF,
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STD_VEC_FIELD_NAME_LENGTH]
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# std::String related constants
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STD_STRING_FIELD_NAMES = ["vec"]
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class Type(object):
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"""
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This class provides a common interface for type-oriented operations.
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Sub-classes are supposed to wrap a debugger-specific type-object and
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provide implementations for the abstract methods in this class.
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"""
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def __init__(self):
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self.__type_kind = None
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def get_unqualified_type_name(self):
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"""
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Implementations of this method should return the unqualified name of the
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type-object they are wrapping. Some examples:
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'int' -> 'int'
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'std::vec::Vec<std::string::String>' -> 'Vec<std::string::String>'
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'&std::option::Option<std::string::String>' -> '&std::option::Option<std::string::String>'
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As you can see, type arguments stay fully qualified.
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"""
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raise NotImplementedError("Override this method")
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def get_dwarf_type_kind(self):
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"""
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Implementations of this method should return the correct
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DWARF_TYPE_CODE_* value for the wrapped type-object.
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"""
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raise NotImplementedError("Override this method")
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def get_fields(self):
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"""
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Implementations of this method should return a list of field-objects of
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this type. For Rust-enums (i.e. with DWARF_TYPE_CODE_UNION) these field-
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objects represent the variants of the enum. Field-objects must have a
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`name` attribute that gives their name as specified in DWARF.
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"""
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assert ((self.get_dwarf_type_kind() == DWARF_TYPE_CODE_STRUCT) or
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(self.get_dwarf_type_kind() == DWARF_TYPE_CODE_UNION))
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raise NotImplementedError("Override this method")
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def get_wrapped_value(self):
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"""
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Returns the debugger-specific type-object wrapped by this object. This
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is sometimes needed for doing things like pointer-arithmetic in GDB.
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"""
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raise NotImplementedError("Override this method")
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def get_type_kind(self):
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"""This method returns the TYPE_KIND_* value for this type-object."""
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if self.__type_kind is None:
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dwarf_type_code = self.get_dwarf_type_kind()
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if dwarf_type_code == DWARF_TYPE_CODE_STRUCT:
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self.__type_kind = self.__classify_struct()
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elif dwarf_type_code == DWARF_TYPE_CODE_UNION:
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self.__type_kind = self.__classify_union()
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elif dwarf_type_code == DWARF_TYPE_CODE_PTR:
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self.__type_kind = TYPE_KIND_PTR
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elif dwarf_type_code == DWARF_TYPE_CODE_ARRAY:
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self.__type_kind = TYPE_KIND_FIXED_SIZE_VEC
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else:
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self.__type_kind = TYPE_KIND_UNKNOWN
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return self.__type_kind
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def __classify_struct(self):
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assert self.get_dwarf_type_kind() == DWARF_TYPE_CODE_STRUCT
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unqualified_type_name = self.get_unqualified_type_name()
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# STR SLICE
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if unqualified_type_name == "&str":
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return TYPE_KIND_STR_SLICE
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# REGULAR SLICE
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if (unqualified_type_name.startswith("&[") and
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unqualified_type_name.endswith("]") and
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self.__conforms_to_field_layout(SLICE_FIELD_NAMES)):
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return TYPE_KIND_SLICE
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fields = self.get_fields()
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field_count = len(fields)
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# EMPTY STRUCT
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if field_count == 0:
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return TYPE_KIND_EMPTY
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# STD VEC
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if (unqualified_type_name.startswith("Vec<") and
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self.__conforms_to_field_layout(STD_VEC_FIELD_NAMES)):
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return TYPE_KIND_STD_VEC
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# STD STRING
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if (unqualified_type_name.startswith("String") and
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self.__conforms_to_field_layout(STD_STRING_FIELD_NAMES)):
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return TYPE_KIND_STD_STRING
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# ENUM VARIANTS
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if fields[0].name == ENUM_DISR_FIELD_NAME:
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if field_count == 1:
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return TYPE_KIND_CSTYLE_VARIANT
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elif self.__all_fields_conform_to_tuple_field_naming(1):
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return TYPE_KIND_TUPLE_VARIANT
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else:
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return TYPE_KIND_STRUCT_VARIANT
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# TUPLE
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if self.__all_fields_conform_to_tuple_field_naming(0):
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if unqualified_type_name.startswith("("):
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return TYPE_KIND_TUPLE
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else:
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return TYPE_KIND_TUPLE_STRUCT
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# REGULAR STRUCT
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return TYPE_KIND_REGULAR_STRUCT
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def __classify_union(self):
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assert self.get_dwarf_type_kind() == DWARF_TYPE_CODE_UNION
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union_members = self.get_fields()
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union_member_count = len(union_members)
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if union_member_count == 0:
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return TYPE_KIND_EMPTY
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elif union_member_count == 1:
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first_variant_name = union_members[0].name
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if first_variant_name is None:
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return TYPE_KIND_SINGLETON_ENUM
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else:
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assert first_variant_name.startswith(ENCODED_ENUM_PREFIX)
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return TYPE_KIND_COMPRESSED_ENUM
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else:
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return TYPE_KIND_REGULAR_ENUM
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def __conforms_to_field_layout(self, expected_fields):
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actual_fields = self.get_fields()
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actual_field_count = len(actual_fields)
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if actual_field_count != len(expected_fields):
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return False
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for i in range(0, actual_field_count):
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if actual_fields[i].name != expected_fields[i]:
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return False
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return True
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def __all_fields_conform_to_tuple_field_naming(self, start_index):
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fields = self.get_fields()
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field_count = len(fields)
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for i in range(start_index, field_count):
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field_name = fields[i].name
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if (field_name is None) or (re.match(r"__\d+$", field_name) is None):
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return False
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return True
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class Value(object):
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"""
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This class provides a common interface for value-oriented operations.
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Sub-classes are supposed to wrap a debugger-specific value-object and
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provide implementations for the abstract methods in this class.
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"""
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def __init__(self, ty):
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self.type = ty
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def get_child_at_index(self, index):
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"""Returns the value of the field, array element or variant at the given index"""
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raise NotImplementedError("Override this method")
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def as_integer(self):
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"""
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Try to convert the wrapped value into a Python integer. This should
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always succeed for values that are pointers or actual integers.
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"""
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raise NotImplementedError("Override this method")
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def get_wrapped_value(self):
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"""
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Returns the debugger-specific value-object wrapped by this object. This
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is sometimes needed for doing things like pointer-arithmetic in GDB.
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"""
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raise NotImplementedError("Override this method")
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class EncodedEnumInfo(object):
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"""
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This class provides facilities for handling enum values with compressed
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encoding where a non-null field in one variant doubles as the discriminant.
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"""
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def __init__(self, enum_val):
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assert enum_val.type.get_type_kind() == TYPE_KIND_COMPRESSED_ENUM
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variant_name = enum_val.type.get_fields()[0].name
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last_separator_index = variant_name.rfind("$")
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start_index = len(ENCODED_ENUM_PREFIX)
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indices_substring = variant_name[start_index:last_separator_index].split("$")
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self.__enum_val = enum_val
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self.__disr_field_indices = [int(index) for index in indices_substring]
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self.__null_variant_name = variant_name[last_separator_index + 1:]
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def is_null_variant(self):
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ty = self.__enum_val.type
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sole_variant_val = self.__enum_val.get_child_at_index(0)
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discriminant_val = sole_variant_val
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for disr_field_index in self.__disr_field_indices:
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discriminant_val = discriminant_val.get_child_at_index(disr_field_index)
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# If the discriminant field is a fat pointer we have to consider the
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# first word as the true discriminant
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if discriminant_val.type.get_dwarf_type_kind() == DWARF_TYPE_CODE_STRUCT:
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discriminant_val = discriminant_val.get_child_at_index(0)
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return discriminant_val.as_integer() == 0
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def get_non_null_variant_val(self):
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return self.__enum_val.get_child_at_index(0)
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def get_null_variant_name(self):
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return self.__null_variant_name
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def get_discriminant_value_as_integer(enum_val):
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assert enum_val.type.get_dwarf_type_kind() == DWARF_TYPE_CODE_UNION
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# we can take any variant here because the discriminant has to be the same
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# for all of them.
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variant_val = enum_val.get_child_at_index(0)
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disr_val = variant_val.get_child_at_index(0)
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return disr_val.as_integer()
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def extract_length_ptr_and_cap_from_std_vec(vec_val):
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assert vec_val.type.get_type_kind() == TYPE_KIND_STD_VEC
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length_field_index = STD_VEC_FIELD_NAMES.index(STD_VEC_FIELD_NAME_LENGTH)
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buf_field_index = STD_VEC_FIELD_NAMES.index(STD_VEC_FIELD_NAME_BUF)
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length = vec_val.get_child_at_index(length_field_index).as_integer()
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buf = vec_val.get_child_at_index(buf_field_index)
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vec_ptr_val = buf.get_child_at_index(0)
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capacity = buf.get_child_at_index(1).as_integer()
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unique_ptr_val = vec_ptr_val.get_child_at_index(0)
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data_ptr = unique_ptr_val.get_child_at_index(0)
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assert data_ptr.type.get_dwarf_type_kind() == DWARF_TYPE_CODE_PTR
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return (length, data_ptr, capacity)
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def extract_length_and_ptr_from_slice(slice_val):
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assert (slice_val.type.get_type_kind() == TYPE_KIND_SLICE or
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slice_val.type.get_type_kind() == TYPE_KIND_STR_SLICE)
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length_field_index = SLICE_FIELD_NAMES.index(SLICE_FIELD_NAME_LENGTH)
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ptr_field_index = SLICE_FIELD_NAMES.index(SLICE_FIELD_NAME_DATA_PTR)
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length = slice_val.get_child_at_index(length_field_index).as_integer()
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data_ptr = slice_val.get_child_at_index(ptr_field_index)
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assert data_ptr.type.get_dwarf_type_kind() == DWARF_TYPE_CODE_PTR
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return (length, data_ptr)
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