"""
Objective-C runtime wrapper for use by LLDB Python formatters
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
"""
import lldb
import lldb.formatters.cache
import lldb.formatters.attrib_fromdict
import functools
import lldb.formatters.Logger
class Utilities:
@staticmethod
def read_ascii(process, pointer, max_len=128):
logger = lldb.formatters.Logger.Logger()
error = lldb.SBError()
content = None
try:
content = process.ReadCStringFromMemory(pointer, max_len, error)
except:
pass
if content is None or len(content) == 0 or error.fail:
return None
return content
@staticmethod
def is_valid_pointer(pointer, pointer_size, allow_tagged=0, allow_NULL=0):
logger = lldb.formatters.Logger.Logger()
if pointer is None:
return 0
if pointer == 0:
return allow_NULL
if allow_tagged and (pointer % 2) == 1:
return 1
return (pointer % pointer_size) == 0
# Objective-C runtime has a rule that pointers in a class_t will only have bits 0 thru 46 set
# so if any pointer has bits 47 thru 63 high we know that this is not a
# valid isa
@staticmethod
def is_allowed_pointer(pointer):
logger = lldb.formatters.Logger.Logger()
if pointer is None:
return 0
return (pointer & 0xFFFF800000000000) == 0
@staticmethod
def read_child_of(valobj, offset, type):
logger = lldb.formatters.Logger.Logger()
if offset == 0 and type.GetByteSize() == valobj.GetByteSize():
return valobj.GetValueAsUnsigned()
child = valobj.CreateChildAtOffset("childUNK", offset, type)
if child is None or child.IsValid() == 0:
return None
return child.GetValueAsUnsigned()
@staticmethod
def is_valid_identifier(name):
logger = lldb.formatters.Logger.Logger()
if name is None:
return None
if len(name) == 0:
return None
# technically, the ObjC runtime does not enforce any rules about what name a class can have
# in practice, the commonly used byte values for a class name are the letters, digits and some
# symbols: $, %, -, _, .
# WARNING: this means that you cannot use this runtime implementation if you need to deal
# with class names that use anything but what is allowed here
ok_values = dict.fromkeys(
"$%_.-ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz1234567890"
)
return all(c in ok_values for c in name)
@staticmethod
def check_is_osx_lion(target):
logger = lldb.formatters.Logger.Logger()
# assume the only thing that has a Foundation.framework is a Mac
# assume anything < Lion does not even exist
try:
mod = target.module["Foundation"]
except:
mod = None
if mod is None or mod.IsValid() == 0:
return None
ver = mod.GetVersion()
if ver is None or ver == []:
return None
return ver[0] < 900
# a utility method that factors out code common to almost all the formatters
# takes in an SBValue and a metrics object
# returns a class_data and a wrapper (or None, if the runtime alone can't
# decide on a wrapper)
@staticmethod
def prepare_class_detection(valobj, statistics):
logger = lldb.formatters.Logger.Logger()
class_data = ObjCRuntime(valobj)
if class_data.is_valid() == 0:
statistics.metric_hit("invalid_pointer", valobj)
wrapper = InvalidPointer_Description(valobj.GetValueAsUnsigned(0) == 0)
return class_data, wrapper
class_data = class_data.read_class_data()
if class_data.is_valid() == 0:
statistics.metric_hit("invalid_isa", valobj)
wrapper = InvalidISA_Description()
return class_data, wrapper
if class_data.is_kvo():
class_data = class_data.get_superclass()
if class_data.class_name() == "_NSZombie_OriginalClass":
wrapper = ThisIsZombie_Description()
return class_data, wrapper
return class_data, None
class RoT_Data:
def __init__(self, rot_pointer, params):
logger = lldb.formatters.Logger.Logger()
if Utilities.is_valid_pointer(
rot_pointer.GetValueAsUnsigned(), params.pointer_size, allow_tagged=0
):
self.sys_params = params
self.valobj = rot_pointer
# self.flags = Utilities.read_child_of(self.valobj,0,self.sys_params.uint32_t)
# self.instanceStart = Utilities.read_child_of(self.valobj,4,self.sys_params.uint32_t)
self.instanceSize = None # lazy fetching
offset = 24 if self.sys_params.is_64_bit else 16
# self.ivarLayoutPtr = Utilities.read_child_of(self.valobj,offset,self.sys_params.addr_ptr_type)
self.namePointer = Utilities.read_child_of(
self.valobj, offset, self.sys_params.types_cache.addr_ptr_type
)
self.valid = 1 # self.check_valid()
else:
logger >> "Marking as invalid - rot is invalid"
self.valid = 0
if self.valid:
self.name = Utilities.read_ascii(
self.valobj.GetTarget().GetProcess(), self.namePointer
)
if not (Utilities.is_valid_identifier(self.name)):
logger >> "Marking as invalid - name is invalid"
self.valid = 0
# perform sanity checks on the contents of this class_ro_t
def check_valid(self):
self.valid = 1
# misaligned pointers seem to be possible for this field
# if not(Utilities.is_valid_pointer(self.namePointer,self.sys_params.pointer_size,allow_tagged=0)):
# self.valid = 0
# pass
def __str__(self):
logger = lldb.formatters.Logger.Logger()
return (
"instanceSize = "
+ hex(self.instance_size())
+ "\n"
+ "namePointer = "
+ hex(self.namePointer)
+ " --> "
+ self.name
)
def is_valid(self):
return self.valid
def instance_size(self, align=0):
logger = lldb.formatters.Logger.Logger()
if self.is_valid() == 0:
return None
if self.instanceSize is None:
self.instanceSize = Utilities.read_child_of(
self.valobj, 8, self.sys_params.types_cache.uint32_t
)
if align:
unalign = self.instance_size(0)
if self.sys_params.is_64_bit:
return ((unalign + 7) & ~7) % 0x100000000
else:
return ((unalign + 3) & ~3) % 0x100000000
else:
return self.instanceSize
class RwT_Data:
def __init__(self, rwt_pointer, params):
logger = lldb.formatters.Logger.Logger()
if Utilities.is_valid_pointer(
rwt_pointer.GetValueAsUnsigned(), params.pointer_size, allow_tagged=0
):
self.sys_params = params
self.valobj = rwt_pointer
# self.flags = Utilities.read_child_of(self.valobj,0,self.sys_params.uint32_t)
# self.version = Utilities.read_child_of(self.valobj,4,self.sys_params.uint32_t)
self.roPointer = Utilities.read_child_of(
self.valobj, 8, self.sys_params.types_cache.addr_ptr_type
)
self.check_valid()
else:
logger >> "Marking as invalid - rwt is invald"
self.valid = 0
if self.valid:
self.rot = self.valobj.CreateValueFromData(
"rot",
lldb.SBData.CreateDataFromUInt64Array(
self.sys_params.endianness,
self.sys_params.pointer_size,
[self.roPointer],
),
self.sys_params.types_cache.addr_ptr_type,
)
# self.rot = self.valobj.CreateValueFromAddress("rot",self.roPointer,self.sys_params.types_cache.addr_ptr_type).AddressOf()
self.data = RoT_Data(self.rot, self.sys_params)
# perform sanity checks on the contents of this class_rw_t
def check_valid(self):
logger = lldb.formatters.Logger.Logger()
self.valid = 1
if not (
Utilities.is_valid_pointer(
self.roPointer, self.sys_params.pointer_size, allow_tagged=0
)
):
logger >> "Marking as invalid - ropointer is invalid"
self.valid = 0
def __str__(self):
logger = lldb.formatters.Logger.Logger()
return "roPointer = " + hex(self.roPointer)
def is_valid(self):
logger = lldb.formatters.Logger.Logger()
if self.valid:
return self.data.is_valid()
return 0
class Class_Data_V2:
def __init__(self, isa_pointer, params):
logger = lldb.formatters.Logger.Logger()
if (isa_pointer is not None) and (
Utilities.is_valid_pointer(
isa_pointer.GetValueAsUnsigned(), params.pointer_size, allow_tagged=0
)
):
self.sys_params = params
self.valobj = isa_pointer
self.check_valid()
else:
logger >> "Marking as invalid - isa is invalid or None"
self.valid = 0
if self.valid:
self.rwt = self.valobj.CreateValueFromData(
"rwt",
lldb.SBData.CreateDataFromUInt64Array(
self.sys_params.endianness,
self.sys_params.pointer_size,
[self.dataPointer],
),
self.sys_params.types_cache.addr_ptr_type,
)
# self.rwt = self.valobj.CreateValueFromAddress("rwt",self.dataPointer,self.sys_params.types_cache.addr_ptr_type).AddressOf()
self.data = RwT_Data(self.rwt, self.sys_params)
# perform sanity checks on the contents of this class_t
# this call tries to minimize the amount of data fetched- as soon as we have "proven"
# that we have an invalid object, we stop reading
def check_valid(self):
logger = lldb.formatters.Logger.Logger()
self.valid = 1
self.isaPointer = Utilities.read_child_of(
self.valobj, 0, self.sys_params.types_cache.addr_ptr_type
)
if not (
Utilities.is_valid_pointer(
self.isaPointer, self.sys_params.pointer_size, allow_tagged=0
)
):
logger >> "Marking as invalid - isaPointer is invalid"
self.valid = 0
return
if not (Utilities.is_allowed_pointer(self.isaPointer)):
logger >> "Marking as invalid - isaPointer is not allowed"
self.valid = 0
return
self.cachePointer = Utilities.read_child_of(
self.valobj,
2 * self.sys_params.pointer_size,
self.sys_params.types_cache.addr_ptr_type,
)
if not (
Utilities.is_valid_pointer(
self.cachePointer, self.sys_params.pointer_size, allow_tagged=0
)
):
logger >> "Marking as invalid - cachePointer is invalid"
self.valid = 0
return
if not (Utilities.is_allowed_pointer(self.cachePointer)):
logger >> "Marking as invalid - cachePointer is not allowed"
self.valid = 0
return
self.dataPointer = Utilities.read_child_of(
self.valobj,
4 * self.sys_params.pointer_size,
self.sys_params.types_cache.addr_ptr_type,
)
if not (
Utilities.is_valid_pointer(
self.dataPointer, self.sys_params.pointer_size, allow_tagged=0
)
):
logger >> "Marking as invalid - dataPointer is invalid"
self.valid = 0
return
if not (Utilities.is_allowed_pointer(self.dataPointer)):
logger >> "Marking as invalid - dataPointer is not allowed"
self.valid = 0
return
self.superclassIsaPointer = Utilities.read_child_of(
self.valobj,
1 * self.sys_params.pointer_size,
self.sys_params.types_cache.addr_ptr_type,
)
if not (
Utilities.is_valid_pointer(
self.superclassIsaPointer,
self.sys_params.pointer_size,
allow_tagged=0,
allow_NULL=1,
)
):
logger >> "Marking as invalid - superclassIsa is invalid"
self.valid = 0
return
if not (Utilities.is_allowed_pointer(self.superclassIsaPointer)):
logger >> "Marking as invalid - superclassIsa is not allowed"
self.valid = 0
return
# in general, KVO is implemented by transparently subclassing
# however, there could be exceptions where a class does something else
# internally to implement the feature - this method will have no clue that a class
# has been KVO'ed unless the standard implementation technique is used
def is_kvo(self):
logger = lldb.formatters.Logger.Logger()
if self.is_valid():
if self.class_name().startswith("NSKVONotifying_"):
return 1
return 0
# some CF classes have a valid ObjC isa in their CFRuntimeBase
# but instead of being class-specific this isa points to a match-'em-all class
# which is __NSCFType (the versions without __ also exists and we are matching to it
# just to be on the safe side)
def is_cftype(self):
logger = lldb.formatters.Logger.Logger()
if self.is_valid():
return self.class_name() == "__NSCFType" or self.class_name() == "NSCFType"
def get_superclass(self):
logger = lldb.formatters.Logger.Logger()
if self.is_valid():
parent_isa_pointer = self.valobj.CreateChildAtOffset(
"parent_isa",
self.sys_params.pointer_size,
self.sys_params.addr_ptr_type,
)
return Class_Data_V2(parent_isa_pointer, self.sys_params)
else:
return None
def class_name(self):
logger = lldb.formatters.Logger.Logger()
if self.is_valid():
return self.data.data.name
else:
return None
def is_valid(self):
logger = lldb.formatters.Logger.Logger()
if self.valid:
return self.data.is_valid()
return 0
def __str__(self):
logger = lldb.formatters.Logger.Logger()
return (
"isaPointer = "
+ hex(self.isaPointer)
+ "\n"
+ "superclassIsaPointer = "
+ hex(self.superclassIsaPointer)
+ "\n"
+ "cachePointer = "
+ hex(self.cachePointer)
+ "\n"
+ "data = "
+ hex(self.dataPointer)
)
def is_tagged(self):
return 0
def instance_size(self, align=0):
logger = lldb.formatters.Logger.Logger()
if self.is_valid() == 0:
return None
return self.rwt.rot.instance_size(align)
# runtime v1 is much less intricate than v2 and stores relevant
# information directly in the class_t object
class Class_Data_V1:
def __init__(self, isa_pointer, params):
logger = lldb.formatters.Logger.Logger()
if (isa_pointer is not None) and (
Utilities.is_valid_pointer(
isa_pointer.GetValueAsUnsigned(), params.pointer_size, allow_tagged=0
)
):
self.valid = 1
self.sys_params = params
self.valobj = isa_pointer
self.check_valid()
else:
logger >> "Marking as invalid - isaPointer is invalid or None"
self.valid = 0
if self.valid:
self.name = Utilities.read_ascii(
self.valobj.GetTarget().GetProcess(), self.namePointer
)
if not (Utilities.is_valid_identifier(self.name)):
logger >> "Marking as invalid - name is not valid"
self.valid = 0
# perform sanity checks on the contents of this class_t
def check_valid(self):
logger = lldb.formatters.Logger.Logger()
self.valid = 1
self.isaPointer = Utilities.read_child_of(
self.valobj, 0, self.sys_params.types_cache.addr_ptr_type
)
if not (
Utilities.is_valid_pointer(
self.isaPointer, self.sys_params.pointer_size, allow_tagged=0
)
):
logger >> "Marking as invalid - isaPointer is invalid"
self.valid = 0
return
self.superclassIsaPointer = Utilities.read_child_of(
self.valobj,
1 * self.sys_params.pointer_size,
self.sys_params.types_cache.addr_ptr_type,
)
if not (
Utilities.is_valid_pointer(
self.superclassIsaPointer,
self.sys_params.pointer_size,
allow_tagged=0,
allow_NULL=1,
)
):
logger >> "Marking as invalid - superclassIsa is invalid"
self.valid = 0
return
self.namePointer = Utilities.read_child_of(
self.valobj,
2 * self.sys_params.pointer_size,
self.sys_params.types_cache.addr_ptr_type,
)
# if not(Utilities.is_valid_pointer(self.namePointer,self.sys_params.pointer_size,allow_tagged=0,allow_NULL=0)):
# self.valid = 0
# return
# in general, KVO is implemented by transparently subclassing
# however, there could be exceptions where a class does something else
# internally to implement the feature - this method will have no clue that a class
# has been KVO'ed unless the standard implementation technique is used
def is_kvo(self):
logger = lldb.formatters.Logger.Logger()
if self.is_valid():
if self.class_name().startswith("NSKVONotifying_"):
return 1
return 0
# some CF classes have a valid ObjC isa in their CFRuntimeBase
# but instead of being class-specific this isa points to a match-'em-all class
# which is __NSCFType (the versions without __ also exists and we are matching to it
# just to be on the safe side)
def is_cftype(self):
logger = lldb.formatters.Logger.Logger()
if self.is_valid():
return self.class_name() == "__NSCFType" or self.class_name() == "NSCFType"
def get_superclass(self):
logger = lldb.formatters.Logger.Logger()
if self.is_valid():
parent_isa_pointer = self.valobj.CreateChildAtOffset(
"parent_isa",
self.sys_params.pointer_size,
self.sys_params.addr_ptr_type,
)
return Class_Data_V1(parent_isa_pointer, self.sys_params)
else:
return None
def class_name(self):
logger = lldb.formatters.Logger.Logger()
if self.is_valid():
return self.name
else:
return None
def is_valid(self):
return self.valid
def __str__(self):
logger = lldb.formatters.Logger.Logger()
return (
"isaPointer = "
+ hex(self.isaPointer)
+ "\n"
+ "superclassIsaPointer = "
+ hex(self.superclassIsaPointer)
+ "\n"
+ "namePointer = "
+ hex(self.namePointer)
+ " --> "
+ self.name
+ "instanceSize = "
+ hex(self.instanceSize())
+ "\n"
)
def is_tagged(self):
return 0
def instance_size(self, align=0):
logger = lldb.formatters.Logger.Logger()
if self.is_valid() == 0:
return None
if self.instanceSize is None:
self.instanceSize = Utilities.read_child_of(
self.valobj,
5 * self.sys_params.pointer_size,
self.sys_params.types_cache.addr_ptr_type,
)
if align:
unalign = self.instance_size(0)
if self.sys_params.is_64_bit:
return ((unalign + 7) & ~7) % 0x100000000
else:
return ((unalign + 3) & ~3) % 0x100000000
else:
return self.instanceSize
# these are the only tagged pointers values for current versions
# of OSX - they might change in future OS releases, and no-one is
# advised to rely on these values, or any of the bitmasking formulas
# in TaggedClass_Data. doing otherwise is at your own risk
TaggedClass_Values_Lion = {
1: "NSNumber",
5: "NSManagedObject",
6: "NSDate",
7: "NSDateTS",
}
TaggedClass_Values_NMOS = {
0: "NSAtom",
3: "NSNumber",
4: "NSDateTS",
5: "NSManagedObject",
6: "NSDate",
}
class TaggedClass_Data:
def __init__(self, pointer, params):
logger = lldb.formatters.Logger.Logger()
global TaggedClass_Values_Lion, TaggedClass_Values_NMOS
self.valid = 1
self.name = None
self.sys_params = params
self.valobj = pointer
self.val = (pointer & ~0x0000000000000000FF) >> 8
self.class_bits = (pointer & 0xE) >> 1
self.i_bits = (pointer & 0xF0) >> 4
if self.sys_params.is_lion:
if self.class_bits in TaggedClass_Values_Lion:
self.name = TaggedClass_Values_Lion[self.class_bits]
else:
logger >> "Marking as invalid - not a good tagged pointer for Lion"
self.valid = 0
else:
if self.class_bits in TaggedClass_Values_NMOS:
self.name = TaggedClass_Values_NMOS[self.class_bits]
else:
logger >> "Marking as invalid - not a good tagged pointer for NMOS"
self.valid = 0
def is_valid(self):
return self.valid
def class_name(self):
logger = lldb.formatters.Logger.Logger()
if self.is_valid():
return self.name
else:
return 0
def value(self):
return self.val if self.is_valid() else None
def info_bits(self):
return self.i_bits if self.is_valid() else None
def is_kvo(self):
return 0
def is_cftype(self):
return 0
# we would need to go around looking for the superclass or ask the runtime
# for now, we seem not to require support for this operation so we will merrily
# pretend to be at a root point in the hierarchy
def get_superclass(self):
return None
# anything that is handled here is tagged
def is_tagged(self):
return 1
# it seems reasonable to say that a tagged pointer is the size of a pointer
def instance_size(self, align=0):
logger = lldb.formatters.Logger.Logger()
if self.is_valid() == 0:
return None
return self.sys_params.pointer_size
class InvalidClass_Data:
def __init__(self):
pass
def is_valid(self):
return 0
class Version:
def __init__(self, major, minor, release, build_string):
self._major = major
self._minor = minor
self._release = release
self._build_string = build_string
def get_major(self):
return self._major
def get_minor(self):
return self._minor
def get_release(self):
return self._release
def get_build_string(self):
return self._build_string
major = property(get_major, None)
minor = property(get_minor, None)
release = property(get_release, None)
build_string = property(get_build_string, None)
def __lt__(self, other):
if self.major < other.major:
return 1
if self.minor < other.minor:
return 1
if self.release < other.release:
return 1
# build strings are not compared since they are heavily platform-dependent and might not always
# be available
return 0
def __eq__(self, other):
return (
(self.major == other.major)
and (self.minor == other.minor)
and (self.release == other.release)
and (self.build_string == other.build_string)
)
# Python 2.6 doesn't have functools.total_ordering, so we have to implement
# other comparators
def __gt__(self, other):
return other < self
def __le__(self, other):
return not other < self
def __ge__(self, other):
return not self < other
runtime_version = lldb.formatters.cache.Cache()
os_version = lldb.formatters.cache.Cache()
types_caches = lldb.formatters.cache.Cache()
isa_caches = lldb.formatters.cache.Cache()
class SystemParameters:
def __init__(self, valobj):
logger = lldb.formatters.Logger.Logger()
self.adjust_for_architecture(valobj)
self.adjust_for_process(valobj)
def adjust_for_process(self, valobj):
logger = lldb.formatters.Logger.Logger()
global runtime_version
global os_version
global types_caches
global isa_caches
process = valobj.GetTarget().GetProcess()
# using the unique ID for added guarantees (see svn revision 172628 for
# further details)
self.pid = process.GetUniqueID()
if runtime_version.look_for_key(self.pid):
self.runtime_version = runtime_version.get_value(self.pid)
else:
self.runtime_version = ObjCRuntime.runtime_version(process)
runtime_version.add_item(self.pid, self.runtime_version)
if os_version.look_for_key(self.pid):
self.is_lion = os_version.get_value(self.pid)
else:
self.is_lion = Utilities.check_is_osx_lion(valobj.GetTarget())
os_version.add_item(self.pid, self.is_lion)
if types_caches.look_for_key(self.pid):
self.types_cache = types_caches.get_value(self.pid)
else:
self.types_cache = lldb.formatters.attrib_fromdict.AttributesDictionary(
allow_reset=0
)
self.types_cache.addr_type = valobj.GetType().GetBasicType(
lldb.eBasicTypeUnsignedLong
)
self.types_cache.addr_ptr_type = self.types_cache.addr_type.GetPointerType()
self.types_cache.uint32_t = valobj.GetType().GetBasicType(
lldb.eBasicTypeUnsignedInt
)
types_caches.add_item(self.pid, self.types_cache)
if isa_caches.look_for_key(self.pid):
self.isa_cache = isa_caches.get_value(self.pid)
else:
self.isa_cache = lldb.formatters.cache.Cache()
isa_caches.add_item(self.pid, self.isa_cache)
def adjust_for_architecture(self, valobj):
process = valobj.GetTarget().GetProcess()
self.pointer_size = process.GetAddressByteSize()
self.is_64_bit = self.pointer_size == 8
self.endianness = process.GetByteOrder()
self.is_little = self.endianness == lldb.eByteOrderLittle
self.cfruntime_size = 16 if self.is_64_bit else 8
# a simple helper function that makes it more explicit that one is calculating
# an offset that is made up of X pointers and Y bytes of additional data
# taking into account pointer size - if you know there is going to be some padding
# you can pass that in and it will be taken into account (since padding may be different between
# 32 and 64 bit versions, you can pass padding value for both, the right
# one will be used)
def calculate_offset(self, num_pointers=0, bytes_count=0, padding32=0, padding64=0):
value = bytes_count + num_pointers * self.pointer_size
return value + padding64 if self.is_64_bit else value + padding32
class ObjCRuntime:
# the ObjC runtime has no explicit "version" field that we can use
# instead, we discriminate v1 from v2 by looking for the presence
# of a well-known section only present in v1
@staticmethod
def runtime_version(process):
logger = lldb.formatters.Logger.Logger()
if process.IsValid() == 0:
logger >> "No process - bailing out"
return None
target = process.GetTarget()
num_modules = target.GetNumModules()
module_objc = None
for idx in range(num_modules):
module = target.GetModuleAtIndex(idx)
if module.GetFileSpec().GetFilename() == "libobjc.A.dylib":
module_objc = module
break
if module_objc is None or module_objc.IsValid() == 0:
logger >> "no libobjc - bailing out"
return None
num_sections = module.GetNumSections()
section_objc = None
for idx in range(num_sections):
section = module.GetSectionAtIndex(idx)
if section.GetName() == "__OBJC":
section_objc = section
break
if section_objc is not None and section_objc.IsValid():
logger >> "found __OBJC: v1"
return 1
logger >> "no __OBJC: v2"
return 2
@staticmethod
def runtime_from_isa(isa):
logger = lldb.formatters.Logger.Logger()
runtime = ObjCRuntime(isa)
runtime.isa = isa
return runtime
def __init__(self, valobj):
logger = lldb.formatters.Logger.Logger()
self.valobj = valobj
self.adjust_for_architecture()
self.sys_params = SystemParameters(self.valobj)
self.unsigned_value = self.valobj.GetValueAsUnsigned()
self.isa_value = None
def adjust_for_architecture(self):
pass
# an ObjC pointer can either be tagged or must be aligned
def is_tagged(self):
logger = lldb.formatters.Logger.Logger()
if self.valobj is None:
return 0
return Utilities.is_valid_pointer(
self.unsigned_value, self.sys_params.pointer_size, allow_tagged=1
) and not (
Utilities.is_valid_pointer(
self.unsigned_value, self.sys_params.pointer_size, allow_tagged=0
)
)
def is_valid(self):
logger = lldb.formatters.Logger.Logger()
if self.valobj is None:
return 0
if self.valobj.IsInScope() == 0:
return 0
return Utilities.is_valid_pointer(
self.unsigned_value, self.sys_params.pointer_size, allow_tagged=1
)
def is_nil(self):
return self.unsigned_value == 0
def read_isa(self):
logger = lldb.formatters.Logger.Logger()
if self.isa_value is not None:
logger >> "using cached isa"
return self.isa_value
self.isa_pointer = self.valobj.CreateChildAtOffset(
"cfisa", 0, self.sys_params.types_cache.addr_ptr_type
)
if self.isa_pointer is None or self.isa_pointer.IsValid() == 0:
logger >> "invalid isa - bailing out"
return None
self.isa_value = self.isa_pointer.GetValueAsUnsigned(1)
if self.isa_value == 1:
logger >> "invalid isa value - bailing out"
return None
return Ellipsis
def read_class_data(self):
logger = lldb.formatters.Logger.Logger()
global isa_cache
if self.is_tagged():
# tagged pointers only exist in ObjC v2
if self.sys_params.runtime_version == 2:
logger >> "on v2 and tagged - maybe"
# not every odd-valued pointer is actually tagged. most are just plain wrong
# we could try and predetect this before even creating a TaggedClass_Data object
# but unless performance requires it, this seems a cleaner way
# to tackle the task
tentative_tagged = TaggedClass_Data(
self.unsigned_value, self.sys_params
)
if tentative_tagged.is_valid():
logger >> "truly tagged"
return tentative_tagged
else:
logger >> "not tagged - error"
return InvalidClass_Data()
else:
logger >> "on v1 and tagged - error"
return InvalidClass_Data()
if self.is_valid() == 0 or self.read_isa() is None:
return InvalidClass_Data()
data = self.sys_params.isa_cache.get_value(self.isa_value, default=None)
if data is not None:
return data
if self.sys_params.runtime_version == 2:
data = Class_Data_V2(self.isa_pointer, self.sys_params)
else:
data = Class_Data_V1(self.isa_pointer, self.sys_params)
if data is None:
return InvalidClass_Data()
if data.is_valid():
self.sys_params.isa_cache.add_item(self.isa_value, data, ok_to_replace=1)
return data
# these classes below can be used by the data formatters to provide a
# consistent message that describes a given runtime-generated situation
class SpecialSituation_Description:
def message(self):
return ""
class InvalidPointer_Description(SpecialSituation_Description):
def __init__(self, nil):
self.is_nil = nil
def message(self):
if self.is_nil:
return '@"<nil>"'
else:
return "<invalid pointer>"
class InvalidISA_Description(SpecialSituation_Description):
def __init__(self):
pass
def message(self):
return "<not an Objective-C object>"
class ThisIsZombie_Description(SpecialSituation_Description):
def message(self):
return "<freed object>"
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