# DExTer : Debugging Experience Tester
# ~~~~~~ ~ ~~ ~ ~~
#
# Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
# See https://llvm.org/LICENSE.txt for license information.
# SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
"""DexExpectWatch base class, holds logic for how to build and process expected
watch commands.
"""
import abc
import difflib
import os
import math
from collections import namedtuple
from pathlib import PurePath
from dex.command.CommandBase import CommandBase, StepExpectInfo
from dex.command.StepValueInfo import StepValueInfo
from dex.utils.Exceptions import NonFloatValueInCommand
class AddressExpression(object):
def __init__(self, name, offset=0):
self.name = name
self.offset = offset
def is_resolved(self, resolutions):
return self.name in resolutions
# Given the resolved value of the address, resolve the final value of
# this expression.
def resolved_value(self, resolutions):
if not self.name in resolutions or resolutions[self.name] is None:
return None
# Technically we should fill(8) if we're debugging on a 32bit architecture?
return format_address(resolutions[self.name] + self.offset)
def format_address(value, address_width=64):
return "0x" + hex(value)[2:].zfill(math.ceil(address_width / 4))
def resolved_value(value, resolutions):
return (
value.resolved_value(resolutions)
if isinstance(value, AddressExpression)
else value
)
class DexExpectWatchBase(CommandBase):
def __init__(self, *args, **kwargs):
if len(args) < 2:
raise TypeError("expected at least two args")
self.expression = args[0]
self.values = [
arg if isinstance(arg, AddressExpression) else str(arg) for arg in args[1:]
]
try:
on_line = kwargs.pop("on_line")
self._from_line = on_line
self._to_line = on_line
except KeyError:
self._from_line = kwargs.pop("from_line", 1)
self._to_line = kwargs.pop("to_line", 999999)
self._require_in_order = kwargs.pop("require_in_order", True)
self.float_range = kwargs.pop("float_range", None)
if self.float_range is not None:
for value in self.values:
try:
float(value)
except ValueError:
raise NonFloatValueInCommand(
f"Non-float value '{value}' when float_range arg provided"
)
if kwargs:
raise TypeError("unexpected named args: {}".format(", ".join(kwargs)))
# Number of times that this watch has been encountered.
self.times_encountered = 0
# We'll pop from this set as we encounter values so anything left at
# the end can be considered as not having been seen.
self._missing_values = set(self.values)
self.misordered_watches = []
# List of StepValueInfos for any watch that is encountered as invalid.
self.invalid_watches = []
# List of StepValueInfo any any watch where we couldn't retrieve its
# data.
self.irretrievable_watches = []
# List of StepValueInfos for any watch that is encountered as having
# been optimized out.
self.optimized_out_watches = []
# List of StepValueInfos for any watch that is encountered that has an
# expected value.
self.expected_watches = []
# List of StepValueInfos for any watch that is encountered that has an
# unexpected value.
self.unexpected_watches = []
# List of StepValueInfos for all observed watches that were not
# invalid, irretrievable, or optimized out (combines expected and
# unexpected).
self.observed_watches = []
# dict of address names to their final resolved values, None until it
# gets assigned externally.
self.address_resolutions = None
super(DexExpectWatchBase, self).__init__()
def resolve_value(self, value):
return (
value.resolved_value(self.address_resolutions)
if isinstance(value, AddressExpression)
else value
)
def describe_value(self, value):
if isinstance(value, AddressExpression):
offset = ""
if value.offset > 0:
offset = f"+{value.offset}"
elif value.offset < 0:
offset = str(value.offset)
desc = f"address '{value.name}'{offset}"
if self.resolve_value(value) is not None:
desc += f" ({self.resolve_value(value)})"
return desc
return value
def get_watches(self):
return [
StepExpectInfo(
self.expression, self.path, 0, range(self._from_line, self._to_line + 1)
)
]
@property
def line_range(self):
return list(range(self._from_line, self._to_line + 1))
@property
def missing_values(self):
return sorted(list(self.describe_value(v) for v in self._missing_values))
@property
def encountered_values(self):
return sorted(
list(
set(
self.describe_value(v)
for v in set(self.values) - self._missing_values
)
)
)
@abc.abstractmethod
def _get_expected_field(self, watch):
"""Return a field from watch that this ExpectWatch command is checking."""
def _match_expected_floating_point(self, value):
"""Checks to see whether value is a float that falls within the
acceptance range of one of this command's expected float values, and
returns the expected value if so; otherwise returns the original
value."""
try:
value_as_float = float(value)
except ValueError:
return value
possible_values = self.values
for expected in possible_values:
try:
expected_as_float = float(expected)
difference = abs(value_as_float - expected_as_float)
if difference <= self.float_range:
return expected
except ValueError:
pass
return value
def _maybe_fix_float(self, value):
if self.float_range is not None:
return self._match_expected_floating_point(value)
else:
return value
def _handle_watch(self, step_info):
self.times_encountered += 1
if not step_info.watch_info.could_evaluate:
self.invalid_watches.append(step_info)
return
if step_info.watch_info.is_optimized_away:
self.optimized_out_watches.append(step_info)
return
if step_info.watch_info.is_irretrievable:
self.irretrievable_watches.append(step_info)
return
expected_value = self._maybe_fix_float(step_info.expected_value)
# Check to see if this value matches with a resolved address.
matching_address = None
for v in self.values:
if (
isinstance(v, AddressExpression)
and v.name in self.address_resolutions
and self.resolve_value(v) == expected_value
):
matching_address = v
break
# If this is not an expected value, either a direct value or an address,
# then this is an unexpected watch.
if expected_value not in self.values and matching_address is None:
self.unexpected_watches.append(step_info)
return
self.expected_watches.append(step_info)
value_to_remove = (
matching_address if matching_address is not None else expected_value
)
try:
self._missing_values.remove(value_to_remove)
except KeyError:
pass
def _check_watch_order(self, actual_watches, expected_values):
"""Use difflib to figure out whether the values are in the expected order
or not.
"""
differences = []
actual_values = [
self._maybe_fix_float(w.expected_value) for w in actual_watches
]
value_differences = list(
difflib.Differ().compare(actual_values, expected_values)
)
missing_value = False
index = 0
for vd in value_differences:
kind = vd[0]
if kind == "+":
# A value that is encountered in the expected list but not in the
# actual list. We'll keep a note that something is wrong and flag
# the next value that matches as misordered.
missing_value = True
elif kind == " ":
# This value is as expected. It might still be wrong if we've
# previously encountered a value that is in the expected list but
# not the actual list.
if missing_value:
missing_value = False
differences.append(actual_watches[index])
index += 1
elif kind == "-":
# A value that is encountered in the actual list but not the
# expected list.
differences.append(actual_watches[index])
index += 1
else:
assert False, "unexpected diff:{}".format(vd)
return differences
def eval(self, step_collection):
for step in step_collection.steps:
loc = step.current_location
if (
loc.path
and self.path
and PurePath(loc.path) == PurePath(self.path)
and loc.lineno in self.line_range
):
try:
watch = step.program_state.frames[0].watches[self.expression]
except KeyError:
pass
else:
expected_field = self._get_expected_field(watch)
step_info = StepValueInfo(step.step_index, watch, expected_field)
self._handle_watch(step_info)
if self._require_in_order:
# A list of all watches where the value has changed.
value_change_watches = []
prev_value = None
all_expected_values = []
for watch in self.expected_watches:
expected_value = self._maybe_fix_float(watch.expected_value)
all_expected_values.append(expected_value)
if expected_value != prev_value:
value_change_watches.append(watch)
prev_value = expected_value
resolved_values = [self.resolve_value(v) for v in self.values]
self.misordered_watches = self._check_watch_order(
value_change_watches,
[v for v in resolved_values if v in all_expected_values],
)
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