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1"""
2Objective-C runtime wrapper for use by LLDB Python formatters
3
4Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
5See https://llvm.org/LICENSE.txt for license information.
6SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
7"""
8import lldb
9import lldb.formatters.cache
10import lldb.formatters.attrib_fromdict
11import functools
12import lldb.formatters.Logger
13
14
15class Utilities:
16
17    @staticmethod
18    def read_ascii(process, pointer, max_len=128):
19        logger = lldb.formatters.Logger.Logger()
20        error = lldb.SBError()
21        content = None
22        try:
23            content = process.ReadCStringFromMemory(pointer, max_len, error)
24        except:
25            pass
26        if content is None or len(content) == 0 or error.fail:
27            return None
28        return content
29
30    @staticmethod
31    def is_valid_pointer(pointer, pointer_size, allow_tagged=0, allow_NULL=0):
32        logger = lldb.formatters.Logger.Logger()
33        if pointer is None:
34            return 0
35        if pointer == 0:
36            return allow_NULL
37        if allow_tagged and (pointer % 2) == 1:
38            return 1
39        return ((pointer % pointer_size) == 0)
40
41    # Objective-C runtime has a rule that pointers in a class_t will only have bits 0 thru 46 set
42    # so if any pointer has bits 47 thru 63 high we know that this is not a
43    # valid isa
44    @staticmethod
45    def is_allowed_pointer(pointer):
46        logger = lldb.formatters.Logger.Logger()
47        if pointer is None:
48            return 0
49        return ((pointer & 0xFFFF800000000000) == 0)
50
51    @staticmethod
52    def read_child_of(valobj, offset, type):
53        logger = lldb.formatters.Logger.Logger()
54        if offset == 0 and type.GetByteSize() == valobj.GetByteSize():
55            return valobj.GetValueAsUnsigned()
56        child = valobj.CreateChildAtOffset("childUNK", offset, type)
57        if child is None or child.IsValid() == 0:
58            return None
59        return child.GetValueAsUnsigned()
60
61    @staticmethod
62    def is_valid_identifier(name):
63        logger = lldb.formatters.Logger.Logger()
64        if name is None:
65            return None
66        if len(name) == 0:
67            return None
68        # technically, the ObjC runtime does not enforce any rules about what name a class can have
69        # in practice, the commonly used byte values for a class name are the letters, digits and some
70        # symbols: $, %, -, _, .
71        # WARNING: this means that you cannot use this runtime implementation if you need to deal
72        # with class names that use anything but what is allowed here
73        ok_values = dict.fromkeys(
74            "$%_.-ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz1234567890")
75        return all(c in ok_values for c in name)
76
77    @staticmethod
78    def check_is_osx_lion(target):
79        logger = lldb.formatters.Logger.Logger()
80        # assume the only thing that has a Foundation.framework is a Mac
81        # assume anything < Lion does not even exist
82        try:
83            mod = target.module['Foundation']
84        except:
85            mod = None
86        if mod is None or mod.IsValid() == 0:
87            return None
88        ver = mod.GetVersion()
89        if ver is None or ver == []:
90            return None
91        return (ver[0] < 900)
92
93    # a utility method that factors out code common to almost all the formatters
94    # takes in an SBValue and a metrics object
95    # returns a class_data and a wrapper (or None, if the runtime alone can't
96    # decide on a wrapper)
97    @staticmethod
98    def prepare_class_detection(valobj, statistics):
99        logger = lldb.formatters.Logger.Logger()
100        class_data = ObjCRuntime(valobj)
101        if class_data.is_valid() == 0:
102            statistics.metric_hit('invalid_pointer', valobj)
103            wrapper = InvalidPointer_Description(
104                valobj.GetValueAsUnsigned(0) == 0)
105            return class_data, wrapper
106        class_data = class_data.read_class_data()
107        if class_data.is_valid() == 0:
108            statistics.metric_hit('invalid_isa', valobj)
109            wrapper = InvalidISA_Description()
110            return class_data, wrapper
111        if class_data.is_kvo():
112            class_data = class_data.get_superclass()
113        if class_data.class_name() == '_NSZombie_OriginalClass':
114            wrapper = ThisIsZombie_Description()
115            return class_data, wrapper
116        return class_data, None
117
118
119class RoT_Data:
120
121    def __init__(self, rot_pointer, params):
122        logger = lldb.formatters.Logger.Logger()
123        if (Utilities.is_valid_pointer(rot_pointer.GetValueAsUnsigned(),
124                                       params.pointer_size, allow_tagged=0)):
125            self.sys_params = params
126            self.valobj = rot_pointer
127            #self.flags = Utilities.read_child_of(self.valobj,0,self.sys_params.uint32_t)
128            #self.instanceStart = Utilities.read_child_of(self.valobj,4,self.sys_params.uint32_t)
129            self.instanceSize = None  # lazy fetching
130            offset = 24 if self.sys_params.is_64_bit else 16
131            #self.ivarLayoutPtr = Utilities.read_child_of(self.valobj,offset,self.sys_params.addr_ptr_type)
132            self.namePointer = Utilities.read_child_of(
133                self.valobj, offset, self.sys_params.types_cache.addr_ptr_type)
134            self.valid = 1  # self.check_valid()
135        else:
136            logger >> "Marking as invalid - rot is invalid"
137            self.valid = 0
138        if self.valid:
139            self.name = Utilities.read_ascii(
140                self.valobj.GetTarget().GetProcess(), self.namePointer)
141            if not(Utilities.is_valid_identifier(self.name)):
142                logger >> "Marking as invalid - name is invalid"
143                self.valid = 0
144
145    # perform sanity checks on the contents of this class_ro_t
146    def check_valid(self):
147        self.valid = 1
148        # misaligned pointers seem to be possible for this field
149        # if not(Utilities.is_valid_pointer(self.namePointer,self.sys_params.pointer_size,allow_tagged=0)):
150        #	self.valid = 0
151        #	pass
152
153    def __str__(self):
154        logger = lldb.formatters.Logger.Logger()
155        return \
156            "instanceSize = " + hex(self.instance_size()) + "\n" + \
157            "namePointer = " + hex(self.namePointer) + " --> " + self.name
158
159    def is_valid(self):
160        return self.valid
161
162    def instance_size(self, align=0):
163        logger = lldb.formatters.Logger.Logger()
164        if self.is_valid() == 0:
165            return None
166        if self.instanceSize is None:
167            self.instanceSize = Utilities.read_child_of(
168                self.valobj, 8, self.sys_params.types_cache.uint32_t)
169        if align:
170            unalign = self.instance_size(0)
171            if self.sys_params.is_64_bit:
172                return ((unalign + 7) & ~7) % 0x100000000
173            else:
174                return ((unalign + 3) & ~3) % 0x100000000
175        else:
176            return self.instanceSize
177
178
179class RwT_Data:
180
181    def __init__(self, rwt_pointer, params):
182        logger = lldb.formatters.Logger.Logger()
183        if (Utilities.is_valid_pointer(rwt_pointer.GetValueAsUnsigned(),
184                                       params.pointer_size, allow_tagged=0)):
185            self.sys_params = params
186            self.valobj = rwt_pointer
187            #self.flags = Utilities.read_child_of(self.valobj,0,self.sys_params.uint32_t)
188            #self.version = Utilities.read_child_of(self.valobj,4,self.sys_params.uint32_t)
189            self.roPointer = Utilities.read_child_of(
190                self.valobj, 8, self.sys_params.types_cache.addr_ptr_type)
191            self.check_valid()
192        else:
193            logger >> "Marking as invalid - rwt is invald"
194            self.valid = 0
195        if self.valid:
196            self.rot = self.valobj.CreateValueFromData(
197                "rot", lldb.SBData.CreateDataFromUInt64Array(
198                    self.sys_params.endianness, self.sys_params.pointer_size, [
199                        self.roPointer]), self.sys_params.types_cache.addr_ptr_type)
200#			self.rot = self.valobj.CreateValueFromAddress("rot",self.roPointer,self.sys_params.types_cache.addr_ptr_type).AddressOf()
201            self.data = RoT_Data(self.rot, self.sys_params)
202
203    # perform sanity checks on the contents of this class_rw_t
204    def check_valid(self):
205        logger = lldb.formatters.Logger.Logger()
206        self.valid = 1
207        if not(
208            Utilities.is_valid_pointer(
209                self.roPointer,
210                self.sys_params.pointer_size,
211                allow_tagged=0)):
212            logger >> "Marking as invalid - ropointer is invalid"
213            self.valid = 0
214
215    def __str__(self):
216        logger = lldb.formatters.Logger.Logger()
217        return \
218            "roPointer = " + hex(self.roPointer)
219
220    def is_valid(self):
221        logger = lldb.formatters.Logger.Logger()
222        if self.valid:
223            return self.data.is_valid()
224        return 0
225
226
227class Class_Data_V2:
228
229    def __init__(self, isa_pointer, params):
230        logger = lldb.formatters.Logger.Logger()
231        if (isa_pointer is not None) and (Utilities.is_valid_pointer(
232                isa_pointer.GetValueAsUnsigned(), params.pointer_size, allow_tagged=0)):
233            self.sys_params = params
234            self.valobj = isa_pointer
235            self.check_valid()
236        else:
237            logger >> "Marking as invalid - isa is invalid or None"
238            self.valid = 0
239        if self.valid:
240            self.rwt = self.valobj.CreateValueFromData(
241                "rwt", lldb.SBData.CreateDataFromUInt64Array(
242                    self.sys_params.endianness, self.sys_params.pointer_size, [
243                        self.dataPointer]), self.sys_params.types_cache.addr_ptr_type)
244#			self.rwt = self.valobj.CreateValueFromAddress("rwt",self.dataPointer,self.sys_params.types_cache.addr_ptr_type).AddressOf()
245            self.data = RwT_Data(self.rwt, self.sys_params)
246
247    # perform sanity checks on the contents of this class_t
248    # this call tries to minimize the amount of data fetched- as soon as we have "proven"
249    # that we have an invalid object, we stop reading
250    def check_valid(self):
251        logger = lldb.formatters.Logger.Logger()
252        self.valid = 1
253
254        self.isaPointer = Utilities.read_child_of(
255            self.valobj, 0, self.sys_params.types_cache.addr_ptr_type)
256        if not(
257            Utilities.is_valid_pointer(
258                self.isaPointer,
259                self.sys_params.pointer_size,
260                allow_tagged=0)):
261            logger >> "Marking as invalid - isaPointer is invalid"
262            self.valid = 0
263            return
264        if not(Utilities.is_allowed_pointer(self.isaPointer)):
265            logger >> "Marking as invalid - isaPointer is not allowed"
266            self.valid = 0
267            return
268
269        self.cachePointer = Utilities.read_child_of(
270            self.valobj,
271            2 * self.sys_params.pointer_size,
272            self.sys_params.types_cache.addr_ptr_type)
273        if not(
274            Utilities.is_valid_pointer(
275                self.cachePointer,
276                self.sys_params.pointer_size,
277                allow_tagged=0)):
278            logger >> "Marking as invalid - cachePointer is invalid"
279            self.valid = 0
280            return
281        if not(Utilities.is_allowed_pointer(self.cachePointer)):
282            logger >> "Marking as invalid - cachePointer is not allowed"
283            self.valid = 0
284            return
285        self.dataPointer = Utilities.read_child_of(
286            self.valobj,
287            4 * self.sys_params.pointer_size,
288            self.sys_params.types_cache.addr_ptr_type)
289        if not(
290            Utilities.is_valid_pointer(
291                self.dataPointer,
292                self.sys_params.pointer_size,
293                allow_tagged=0)):
294            logger >> "Marking as invalid - dataPointer is invalid"
295            self.valid = 0
296            return
297        if not(Utilities.is_allowed_pointer(self.dataPointer)):
298            logger >> "Marking as invalid - dataPointer is not allowed"
299            self.valid = 0
300            return
301
302        self.superclassIsaPointer = Utilities.read_child_of(
303            self.valobj,
304            1 * self.sys_params.pointer_size,
305            self.sys_params.types_cache.addr_ptr_type)
306        if not(
307            Utilities.is_valid_pointer(
308                self.superclassIsaPointer,
309                self.sys_params.pointer_size,
310                allow_tagged=0,
311                allow_NULL=1)):
312            logger >> "Marking as invalid - superclassIsa is invalid"
313            self.valid = 0
314            return
315        if not(Utilities.is_allowed_pointer(self.superclassIsaPointer)):
316            logger >> "Marking as invalid - superclassIsa is not allowed"
317            self.valid = 0
318            return
319
320    # in general, KVO is implemented by transparently subclassing
321    # however, there could be exceptions where a class does something else
322    # internally to implement the feature - this method will have no clue that a class
323    # has been KVO'ed unless the standard implementation technique is used
324    def is_kvo(self):
325        logger = lldb.formatters.Logger.Logger()
326        if self.is_valid():
327            if self.class_name().startswith("NSKVONotifying_"):
328                return 1
329        return 0
330
331    # some CF classes have a valid ObjC isa in their CFRuntimeBase
332    # but instead of being class-specific this isa points to a match-'em-all class
333    # which is __NSCFType (the versions without __ also exists and we are matching to it
334    #                      just to be on the safe side)
335    def is_cftype(self):
336        logger = lldb.formatters.Logger.Logger()
337        if self.is_valid():
338            return self.class_name() == '__NSCFType' or self.class_name() == 'NSCFType'
339
340    def get_superclass(self):
341        logger = lldb.formatters.Logger.Logger()
342        if self.is_valid():
343            parent_isa_pointer = self.valobj.CreateChildAtOffset(
344                "parent_isa", self.sys_params.pointer_size, self.sys_params.addr_ptr_type)
345            return Class_Data_V2(parent_isa_pointer, self.sys_params)
346        else:
347            return None
348
349    def class_name(self):
350        logger = lldb.formatters.Logger.Logger()
351        if self.is_valid():
352            return self.data.data.name
353        else:
354            return None
355
356    def is_valid(self):
357        logger = lldb.formatters.Logger.Logger()
358        if self.valid:
359            return self.data.is_valid()
360        return 0
361
362    def __str__(self):
363        logger = lldb.formatters.Logger.Logger()
364        return 'isaPointer = ' + hex(self.isaPointer) + "\n" + \
365            "superclassIsaPointer = " + hex(self.superclassIsaPointer) + "\n" + \
366            "cachePointer = " + hex(self.cachePointer) + "\n" + \
367            "data = " + hex(self.dataPointer)
368
369    def is_tagged(self):
370        return 0
371
372    def instance_size(self, align=0):
373        logger = lldb.formatters.Logger.Logger()
374        if self.is_valid() == 0:
375            return None
376        return self.rwt.rot.instance_size(align)
377
378# runtime v1 is much less intricate than v2 and stores relevant
379# information directly in the class_t object
380
381
382class Class_Data_V1:
383
384    def __init__(self, isa_pointer, params):
385        logger = lldb.formatters.Logger.Logger()
386        if (isa_pointer is not None) and (Utilities.is_valid_pointer(
387                isa_pointer.GetValueAsUnsigned(), params.pointer_size, allow_tagged=0)):
388            self.valid = 1
389            self.sys_params = params
390            self.valobj = isa_pointer
391            self.check_valid()
392        else:
393            logger >> "Marking as invalid - isaPointer is invalid or None"
394            self.valid = 0
395        if self.valid:
396            self.name = Utilities.read_ascii(
397                self.valobj.GetTarget().GetProcess(), self.namePointer)
398            if not(Utilities.is_valid_identifier(self.name)):
399                logger >> "Marking as invalid - name is not valid"
400                self.valid = 0
401
402    # perform sanity checks on the contents of this class_t
403    def check_valid(self):
404        logger = lldb.formatters.Logger.Logger()
405        self.valid = 1
406
407        self.isaPointer = Utilities.read_child_of(
408            self.valobj, 0, self.sys_params.types_cache.addr_ptr_type)
409        if not(
410            Utilities.is_valid_pointer(
411                self.isaPointer,
412                self.sys_params.pointer_size,
413                allow_tagged=0)):
414            logger >> "Marking as invalid - isaPointer is invalid"
415            self.valid = 0
416            return
417
418        self.superclassIsaPointer = Utilities.read_child_of(
419            self.valobj,
420            1 * self.sys_params.pointer_size,
421            self.sys_params.types_cache.addr_ptr_type)
422        if not(
423            Utilities.is_valid_pointer(
424                self.superclassIsaPointer,
425                self.sys_params.pointer_size,
426                allow_tagged=0,
427                allow_NULL=1)):
428            logger >> "Marking as invalid - superclassIsa is invalid"
429            self.valid = 0
430            return
431
432        self.namePointer = Utilities.read_child_of(
433            self.valobj,
434            2 * self.sys_params.pointer_size,
435            self.sys_params.types_cache.addr_ptr_type)
436        # if not(Utilities.is_valid_pointer(self.namePointer,self.sys_params.pointer_size,allow_tagged=0,allow_NULL=0)):
437        #	self.valid = 0
438        #	return
439
440    # in general, KVO is implemented by transparently subclassing
441    # however, there could be exceptions where a class does something else
442    # internally to implement the feature - this method will have no clue that a class
443    # has been KVO'ed unless the standard implementation technique is used
444    def is_kvo(self):
445        logger = lldb.formatters.Logger.Logger()
446        if self.is_valid():
447            if self.class_name().startswith("NSKVONotifying_"):
448                return 1
449        return 0
450
451    # some CF classes have a valid ObjC isa in their CFRuntimeBase
452    # but instead of being class-specific this isa points to a match-'em-all class
453    # which is __NSCFType (the versions without __ also exists and we are matching to it
454    #                      just to be on the safe side)
455    def is_cftype(self):
456        logger = lldb.formatters.Logger.Logger()
457        if self.is_valid():
458            return self.class_name() == '__NSCFType' or self.class_name() == 'NSCFType'
459
460    def get_superclass(self):
461        logger = lldb.formatters.Logger.Logger()
462        if self.is_valid():
463            parent_isa_pointer = self.valobj.CreateChildAtOffset(
464                "parent_isa", self.sys_params.pointer_size, self.sys_params.addr_ptr_type)
465            return Class_Data_V1(parent_isa_pointer, self.sys_params)
466        else:
467            return None
468
469    def class_name(self):
470        logger = lldb.formatters.Logger.Logger()
471        if self.is_valid():
472            return self.name
473        else:
474            return None
475
476    def is_valid(self):
477        return self.valid
478
479    def __str__(self):
480        logger = lldb.formatters.Logger.Logger()
481        return 'isaPointer = ' + hex(self.isaPointer) + "\n" + \
482            "superclassIsaPointer = " + hex(self.superclassIsaPointer) + "\n" + \
483            "namePointer = " + hex(self.namePointer) + " --> " + self.name + \
484            "instanceSize = " + hex(self.instanceSize()) + "\n"
485
486    def is_tagged(self):
487        return 0
488
489    def instance_size(self, align=0):
490        logger = lldb.formatters.Logger.Logger()
491        if self.is_valid() == 0:
492            return None
493        if self.instanceSize is None:
494            self.instanceSize = Utilities.read_child_of(
495                self.valobj,
496                5 * self.sys_params.pointer_size,
497                self.sys_params.types_cache.addr_ptr_type)
498        if align:
499            unalign = self.instance_size(0)
500            if self.sys_params.is_64_bit:
501                return ((unalign + 7) & ~7) % 0x100000000
502            else:
503                return ((unalign + 3) & ~3) % 0x100000000
504        else:
505            return self.instanceSize
506
507# these are the only tagged pointers values for current versions
508# of OSX - they might change in future OS releases, and no-one is
509# advised to rely on these values, or any of the bitmasking formulas
510# in TaggedClass_Data. doing otherwise is at your own risk
511TaggedClass_Values_Lion = {1: 'NSNumber',
512                           5: 'NSManagedObject',
513                           6: 'NSDate',
514                           7: 'NSDateTS'}
515TaggedClass_Values_NMOS = {0: 'NSAtom',
516                           3: 'NSNumber',
517                           4: 'NSDateTS',
518                           5: 'NSManagedObject',
519                           6: 'NSDate'}
520
521
522class TaggedClass_Data:
523
524    def __init__(self, pointer, params):
525        logger = lldb.formatters.Logger.Logger()
526        global TaggedClass_Values_Lion, TaggedClass_Values_NMOS
527        self.valid = 1
528        self.name = None
529        self.sys_params = params
530        self.valobj = pointer
531        self.val = (pointer & ~0x0000000000000000FF) >> 8
532        self.class_bits = (pointer & 0xE) >> 1
533        self.i_bits = (pointer & 0xF0) >> 4
534
535        if self.sys_params.is_lion:
536            if self.class_bits in TaggedClass_Values_Lion:
537                self.name = TaggedClass_Values_Lion[self.class_bits]
538            else:
539                logger >> "Marking as invalid - not a good tagged pointer for Lion"
540                self.valid = 0
541        else:
542            if self.class_bits in TaggedClass_Values_NMOS:
543                self.name = TaggedClass_Values_NMOS[self.class_bits]
544            else:
545                logger >> "Marking as invalid - not a good tagged pointer for NMOS"
546                self.valid = 0
547
548    def is_valid(self):
549        return self.valid
550
551    def class_name(self):
552        logger = lldb.formatters.Logger.Logger()
553        if self.is_valid():
554            return self.name
555        else:
556            return 0
557
558    def value(self):
559        return self.val if self.is_valid() else None
560
561    def info_bits(self):
562        return self.i_bits if self.is_valid() else None
563
564    def is_kvo(self):
565        return 0
566
567    def is_cftype(self):
568        return 0
569
570    # we would need to go around looking for the superclass or ask the runtime
571    # for now, we seem not to require support for this operation so we will merrily
572    # pretend to be at a root point in the hierarchy
573    def get_superclass(self):
574        return None
575
576    # anything that is handled here is tagged
577    def is_tagged(self):
578        return 1
579
580    # it seems reasonable to say that a tagged pointer is the size of a pointer
581    def instance_size(self, align=0):
582        logger = lldb.formatters.Logger.Logger()
583        if self.is_valid() == 0:
584            return None
585        return self.sys_params.pointer_size
586
587
588class InvalidClass_Data:
589
590    def __init__(self):
591        pass
592
593    def is_valid(self):
594        return 0
595
596
597class Version:
598
599    def __init__(self, major, minor, release, build_string):
600        self._major = major
601        self._minor = minor
602        self._release = release
603        self._build_string = build_string
604
605    def get_major(self):
606        return self._major
607
608    def get_minor(self):
609        return self._minor
610
611    def get_release(self):
612        return self._release
613
614    def get_build_string(self):
615        return self._build_string
616
617    major = property(get_major, None)
618    minor = property(get_minor, None)
619    release = property(get_release, None)
620    build_string = property(get_build_string, None)
621
622    def __lt__(self, other):
623        if (self.major < other.major):
624            return 1
625        if (self.minor < other.minor):
626            return 1
627        if (self.release < other.release):
628            return 1
629        # build strings are not compared since they are heavily platform-dependent and might not always
630        # be available
631        return 0
632
633    def __eq__(self, other):
634        return (self.major == other.major) and \
635               (self.minor == other.minor) and \
636               (self.release == other.release) and \
637               (self.build_string == other.build_string)
638
639    # Python 2.6 doesn't have functools.total_ordering, so we have to implement
640    # other comparators
641    def __gt__(self, other):
642        return other < self
643
644    def __le__(self, other):
645        return not other < self
646
647    def __ge__(self, other):
648        return not self < other
649
650
651runtime_version = lldb.formatters.cache.Cache()
652os_version = lldb.formatters.cache.Cache()
653types_caches = lldb.formatters.cache.Cache()
654isa_caches = lldb.formatters.cache.Cache()
655
656
657class SystemParameters:
658
659    def __init__(self, valobj):
660        logger = lldb.formatters.Logger.Logger()
661        self.adjust_for_architecture(valobj)
662        self.adjust_for_process(valobj)
663
664    def adjust_for_process(self, valobj):
665        logger = lldb.formatters.Logger.Logger()
666        global runtime_version
667        global os_version
668        global types_caches
669        global isa_caches
670
671        process = valobj.GetTarget().GetProcess()
672        # using the unique ID for added guarantees (see svn revision 172628 for
673        # further details)
674        self.pid = process.GetUniqueID()
675
676        if runtime_version.look_for_key(self.pid):
677            self.runtime_version = runtime_version.get_value(self.pid)
678        else:
679            self.runtime_version = ObjCRuntime.runtime_version(process)
680            runtime_version.add_item(self.pid, self.runtime_version)
681
682        if os_version.look_for_key(self.pid):
683            self.is_lion = os_version.get_value(self.pid)
684        else:
685            self.is_lion = Utilities.check_is_osx_lion(valobj.GetTarget())
686            os_version.add_item(self.pid, self.is_lion)
687
688        if types_caches.look_for_key(self.pid):
689            self.types_cache = types_caches.get_value(self.pid)
690        else:
691            self.types_cache = lldb.formatters.attrib_fromdict.AttributesDictionary(
692                allow_reset=0)
693            self.types_cache.addr_type = valobj.GetType(
694            ).GetBasicType(lldb.eBasicTypeUnsignedLong)
695            self.types_cache.addr_ptr_type = self.types_cache.addr_type.GetPointerType()
696            self.types_cache.uint32_t = valobj.GetType(
697            ).GetBasicType(lldb.eBasicTypeUnsignedInt)
698            types_caches.add_item(self.pid, self.types_cache)
699
700        if isa_caches.look_for_key(self.pid):
701            self.isa_cache = isa_caches.get_value(self.pid)
702        else:
703            self.isa_cache = lldb.formatters.cache.Cache()
704            isa_caches.add_item(self.pid, self.isa_cache)
705
706    def adjust_for_architecture(self, valobj):
707        process = valobj.GetTarget().GetProcess()
708        self.pointer_size = process.GetAddressByteSize()
709        self.is_64_bit = (self.pointer_size == 8)
710        self.endianness = process.GetByteOrder()
711        self.is_little = (self.endianness == lldb.eByteOrderLittle)
712        self.cfruntime_size = 16 if self.is_64_bit else 8
713
714    # a simple helper function that makes it more explicit that one is calculating
715    # an offset that is made up of X pointers and Y bytes of additional data
716    # taking into account pointer size - if you know there is going to be some padding
717    # you can pass that in and it will be taken into account (since padding may be different between
718    # 32 and 64 bit versions, you can pass padding value for both, the right
719    # one will be used)
720    def calculate_offset(
721            self,
722            num_pointers=0,
723            bytes_count=0,
724            padding32=0,
725            padding64=0):
726        value = bytes_count + num_pointers * self.pointer_size
727        return value + padding64 if self.is_64_bit else value + padding32
728
729
730class ObjCRuntime:
731
732    # the ObjC runtime has no explicit "version" field that we can use
733    # instead, we discriminate v1 from v2 by looking for the presence
734    # of a well-known section only present in v1
735    @staticmethod
736    def runtime_version(process):
737        logger = lldb.formatters.Logger.Logger()
738        if process.IsValid() == 0:
739            logger >> "No process - bailing out"
740            return None
741        target = process.GetTarget()
742        num_modules = target.GetNumModules()
743        module_objc = None
744        for idx in range(num_modules):
745            module = target.GetModuleAtIndex(idx)
746            if module.GetFileSpec().GetFilename() == 'libobjc.A.dylib':
747                module_objc = module
748                break
749        if module_objc is None or module_objc.IsValid() == 0:
750            logger >> "no libobjc - bailing out"
751            return None
752        num_sections = module.GetNumSections()
753        section_objc = None
754        for idx in range(num_sections):
755            section = module.GetSectionAtIndex(idx)
756            if section.GetName() == '__OBJC':
757                section_objc = section
758                break
759        if section_objc is not None and section_objc.IsValid():
760            logger >> "found __OBJC: v1"
761            return 1
762        logger >> "no __OBJC: v2"
763        return 2
764
765    @staticmethod
766    def runtime_from_isa(isa):
767        logger = lldb.formatters.Logger.Logger()
768        runtime = ObjCRuntime(isa)
769        runtime.isa = isa
770        return runtime
771
772    def __init__(self, valobj):
773        logger = lldb.formatters.Logger.Logger()
774        self.valobj = valobj
775        self.adjust_for_architecture()
776        self.sys_params = SystemParameters(self.valobj)
777        self.unsigned_value = self.valobj.GetValueAsUnsigned()
778        self.isa_value = None
779
780    def adjust_for_architecture(self):
781        pass
782
783# an ObjC pointer can either be tagged or must be aligned
784    def is_tagged(self):
785        logger = lldb.formatters.Logger.Logger()
786        if self.valobj is None:
787            return 0
788        return (
789            Utilities.is_valid_pointer(
790                self.unsigned_value,
791                self.sys_params.pointer_size,
792                allow_tagged=1) and not(
793                Utilities.is_valid_pointer(
794                    self.unsigned_value,
795                    self.sys_params.pointer_size,
796                    allow_tagged=0)))
797
798    def is_valid(self):
799        logger = lldb.formatters.Logger.Logger()
800        if self.valobj is None:
801            return 0
802        if self.valobj.IsInScope() == 0:
803            return 0
804        return Utilities.is_valid_pointer(
805            self.unsigned_value,
806            self.sys_params.pointer_size,
807            allow_tagged=1)
808
809    def is_nil(self):
810        return self.unsigned_value == 0
811
812    def read_isa(self):
813        logger = lldb.formatters.Logger.Logger()
814        if self.isa_value is not None:
815            logger >> "using cached isa"
816            return self.isa_value
817        self.isa_pointer = self.valobj.CreateChildAtOffset(
818            "cfisa", 0, self.sys_params.types_cache.addr_ptr_type)
819        if self.isa_pointer is None or self.isa_pointer.IsValid() == 0:
820            logger >> "invalid isa - bailing out"
821            return None
822        self.isa_value = self.isa_pointer.GetValueAsUnsigned(1)
823        if self.isa_value == 1:
824            logger >> "invalid isa value - bailing out"
825            return None
826        return Ellipsis
827
828    def read_class_data(self):
829        logger = lldb.formatters.Logger.Logger()
830        global isa_cache
831        if self.is_tagged():
832            # tagged pointers only exist in ObjC v2
833            if self.sys_params.runtime_version == 2:
834                logger >> "on v2 and tagged - maybe"
835                # not every odd-valued pointer is actually tagged. most are just plain wrong
836                # we could try and predetect this before even creating a TaggedClass_Data object
837                # but unless performance requires it, this seems a cleaner way
838                # to tackle the task
839                tentative_tagged = TaggedClass_Data(
840                    self.unsigned_value, self.sys_params)
841                if tentative_tagged.is_valid():
842                    logger >> "truly tagged"
843                    return tentative_tagged
844                else:
845                    logger >> "not tagged - error"
846                    return InvalidClass_Data()
847            else:
848                logger >> "on v1 and tagged - error"
849                return InvalidClass_Data()
850        if self.is_valid() == 0 or self.read_isa() is None:
851            return InvalidClass_Data()
852        data = self.sys_params.isa_cache.get_value(
853            self.isa_value, default=None)
854        if data is not None:
855            return data
856        if self.sys_params.runtime_version == 2:
857            data = Class_Data_V2(self.isa_pointer, self.sys_params)
858        else:
859            data = Class_Data_V1(self.isa_pointer, self.sys_params)
860        if data is None:
861            return InvalidClass_Data()
862        if data.is_valid():
863            self.sys_params.isa_cache.add_item(
864                self.isa_value, data, ok_to_replace=1)
865        return data
866
867# these classes below can be used by the data formatters to provide a
868# consistent message that describes a given runtime-generated situation
869
870
871class SpecialSituation_Description:
872
873    def message(self):
874        return ''
875
876
877class InvalidPointer_Description(SpecialSituation_Description):
878
879    def __init__(self, nil):
880        self.is_nil = nil
881
882    def message(self):
883        if self.is_nil:
884            return '@"<nil>"'
885        else:
886            return '<invalid pointer>'
887
888
889class InvalidISA_Description(SpecialSituation_Description):
890
891    def __init__(self):
892        pass
893
894    def message(self):
895        return '<not an Objective-C object>'
896
897
898class ThisIsZombie_Description(SpecialSituation_Description):
899
900    def message(self):
901        return '<freed object>'
902