1 //===-- NSArray.cpp -------------------------------------------------------===//
2 //
3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4 // See https://llvm.org/LICENSE.txt for license information.
5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6 //
7 //===----------------------------------------------------------------------===//
8 
9 #include "clang/AST/ASTContext.h"
10 #include "clang/Basic/TargetInfo.h"
11 
12 #include "Cocoa.h"
13 
14 #include "Plugins/LanguageRuntime/ObjC/AppleObjCRuntime/AppleObjCRuntime.h"
15 #include "Plugins/TypeSystem/Clang/TypeSystemClang.h"
16 
17 #include "lldb/Core/ValueObject.h"
18 #include "lldb/Core/ValueObjectConstResult.h"
19 #include "lldb/DataFormatters/FormattersHelpers.h"
20 #include "lldb/Expression/FunctionCaller.h"
21 #include "lldb/Target/Language.h"
22 #include "lldb/Target/Target.h"
23 #include "lldb/Utility/DataBufferHeap.h"
24 #include "lldb/Utility/Endian.h"
25 #include "lldb/Utility/Status.h"
26 #include "lldb/Utility/Stream.h"
27 
28 using namespace lldb;
29 using namespace lldb_private;
30 using namespace lldb_private::formatters;
31 
32 namespace lldb_private {
33 namespace formatters {
34 std::map<ConstString, CXXFunctionSummaryFormat::Callback> &
35 NSArray_Additionals::GetAdditionalSummaries() {
36   static std::map<ConstString, CXXFunctionSummaryFormat::Callback> g_map;
37   return g_map;
38 }
39 
40 std::map<ConstString, CXXSyntheticChildren::CreateFrontEndCallback> &
41 NSArray_Additionals::GetAdditionalSynthetics() {
42   static std::map<ConstString, CXXSyntheticChildren::CreateFrontEndCallback>
43       g_map;
44   return g_map;
45 }
46 
47 class NSArrayMSyntheticFrontEndBase : public SyntheticChildrenFrontEnd {
48 public:
49   NSArrayMSyntheticFrontEndBase(lldb::ValueObjectSP valobj_sp);
50 
51   ~NSArrayMSyntheticFrontEndBase() override = default;
52 
53   size_t CalculateNumChildren() override;
54 
55   lldb::ValueObjectSP GetChildAtIndex(size_t idx) override;
56 
57   bool Update() override = 0;
58 
59   bool MightHaveChildren() override;
60 
61   size_t GetIndexOfChildWithName(ConstString name) override;
62 
63 protected:
64   virtual lldb::addr_t GetDataAddress() = 0;
65 
66   virtual uint64_t GetUsedCount() = 0;
67 
68   virtual uint64_t GetOffset() = 0;
69 
70   virtual uint64_t GetSize() = 0;
71 
72   ExecutionContextRef m_exe_ctx_ref;
73   uint8_t m_ptr_size = 8;
74   CompilerType m_id_type;
75 };
76 
77 template <typename D32, typename D64>
78 class GenericNSArrayMSyntheticFrontEnd : public NSArrayMSyntheticFrontEndBase {
79 public:
80   GenericNSArrayMSyntheticFrontEnd(lldb::ValueObjectSP valobj_sp);
81 
82   ~GenericNSArrayMSyntheticFrontEnd() override;
83 
84   bool Update() override;
85 
86 protected:
87   lldb::addr_t GetDataAddress() override;
88 
89   uint64_t GetUsedCount() override;
90 
91   uint64_t GetOffset() override;
92 
93   uint64_t GetSize() override;
94 
95 private:
96   D32 *m_data_32;
97   D64 *m_data_64;
98 };
99 
100 namespace Foundation1010 {
101   namespace {
102     struct DataDescriptor_32 {
103       uint32_t _used;
104       uint32_t _offset;
105       uint32_t _size : 28;
106       uint64_t _priv1 : 4;
107       uint32_t _priv2;
108       uint32_t _data;
109     };
110 
111     struct DataDescriptor_64 {
112       uint64_t _used;
113       uint64_t _offset;
114       uint64_t _size : 60;
115       uint64_t _priv1 : 4;
116       uint32_t _priv2;
117       uint64_t _data;
118     };
119   }
120 
121   using NSArrayMSyntheticFrontEnd =
122       GenericNSArrayMSyntheticFrontEnd<DataDescriptor_32, DataDescriptor_64>;
123 }
124 
125 namespace Foundation1428 {
126   namespace {
127     struct DataDescriptor_32 {
128       uint32_t _used;
129       uint32_t _offset;
130       uint32_t _size;
131       uint32_t _data;
132     };
133 
134     struct DataDescriptor_64 {
135       uint64_t _used;
136       uint64_t _offset;
137       uint64_t _size;
138       uint64_t _data;
139     };
140   }
141 
142   using NSArrayMSyntheticFrontEnd =
143       GenericNSArrayMSyntheticFrontEnd<DataDescriptor_32, DataDescriptor_64>;
144 }
145 
146 namespace Foundation1437 {
147   template <typename PtrType>
148   struct DataDescriptor {
149     PtrType _cow;
150     // __deque
151     PtrType _data;
152     uint32_t _offset;
153     uint32_t _size;
154     uint32_t _muts;
155     uint32_t _used;
156   };
157 
158   using NSArrayMSyntheticFrontEnd =
159      GenericNSArrayMSyntheticFrontEnd<
160         DataDescriptor<uint32_t>, DataDescriptor<uint64_t>>;
161 
162   template <typename DD>
163   uint64_t
164   __NSArrayMSize_Impl(lldb_private::Process &process,
165                       lldb::addr_t valobj_addr, Status &error) {
166     const lldb::addr_t start_of_descriptor =
167     valobj_addr + process.GetAddressByteSize();
168     DD descriptor = DD();
169     process.ReadMemory(start_of_descriptor, &descriptor,
170                        sizeof(descriptor), error);
171     if (error.Fail()) {
172       return 0;
173     }
174     return descriptor._used;
175   }
176 
177   uint64_t
178   __NSArrayMSize(lldb_private::Process &process, lldb::addr_t valobj_addr,
179                  Status &error) {
180     if (process.GetAddressByteSize() == 4) {
181       return __NSArrayMSize_Impl<DataDescriptor<uint32_t>>(process, valobj_addr,
182                                                            error);
183     } else {
184       return __NSArrayMSize_Impl<DataDescriptor<uint64_t>>(process, valobj_addr,
185                                                            error);
186     }
187   }
188 
189 }
190 
191 namespace CallStackArray {
192 struct DataDescriptor_32 {
193   uint32_t _data;
194   uint32_t _used;
195   uint32_t _offset;
196   const uint32_t _size = 0;
197 };
198 
199 struct DataDescriptor_64 {
200   uint64_t _data;
201   uint64_t _used;
202   uint64_t _offset;
203   const uint64_t _size = 0;
204 };
205 
206 using NSCallStackArraySyntheticFrontEnd =
207     GenericNSArrayMSyntheticFrontEnd<DataDescriptor_32, DataDescriptor_64>;
208 } // namespace CallStackArray
209 
210 template <typename D32, typename D64, bool Inline>
211 class GenericNSArrayISyntheticFrontEnd : public SyntheticChildrenFrontEnd {
212 public:
213   GenericNSArrayISyntheticFrontEnd(lldb::ValueObjectSP valobj_sp);
214 
215   ~GenericNSArrayISyntheticFrontEnd() override;
216 
217   size_t CalculateNumChildren() override;
218 
219   lldb::ValueObjectSP GetChildAtIndex(size_t idx) override;
220 
221   bool Update() override;
222 
223   bool MightHaveChildren() override;
224 
225   size_t GetIndexOfChildWithName(ConstString name) override;
226 
227 private:
228   ExecutionContextRef m_exe_ctx_ref;
229   uint8_t m_ptr_size = 8;
230 
231   D32 *m_data_32;
232   D64 *m_data_64;
233   CompilerType m_id_type;
234 };
235 
236 namespace Foundation1300 {
237     struct IDD32 {
238         uint32_t used;
239         uint32_t list;
240     };
241 
242     struct IDD64 {
243         uint64_t used;
244         uint64_t list;
245     };
246 
247     using NSArrayISyntheticFrontEnd =
248         GenericNSArrayISyntheticFrontEnd<IDD32, IDD64, true>;
249 }
250 
251 namespace Foundation1430 {
252     using NSArrayISyntheticFrontEnd =
253         Foundation1428::NSArrayMSyntheticFrontEnd;
254 }
255 
256 namespace Foundation1436 {
257     struct IDD32 {
258         uint32_t used;
259         uint32_t list; // in Inline cases, this is the first element
260     };
261 
262     struct IDD64 {
263         uint64_t used;
264         uint64_t list; // in Inline cases, this is the first element
265     };
266 
267     using NSArrayI_TransferSyntheticFrontEnd =
268         GenericNSArrayISyntheticFrontEnd<IDD32, IDD64, false>;
269 
270     using NSArrayISyntheticFrontEnd =
271         GenericNSArrayISyntheticFrontEnd<IDD32, IDD64, true>;
272 
273     using NSFrozenArrayMSyntheticFrontEnd =
274         Foundation1437::NSArrayMSyntheticFrontEnd;
275 
276     uint64_t
277     __NSFrozenArrayMSize(lldb_private::Process &process, lldb::addr_t valobj_addr,
278                          Status &error) {
279       return Foundation1437::__NSArrayMSize(process, valobj_addr, error);
280     }
281 }
282 
283 namespace ConstantArray {
284 
285 struct ConstantArray32 {
286   uint64_t used;
287   uint32_t list;
288 };
289 
290 struct ConstantArray64 {
291   uint64_t used;
292   uint64_t list;
293 };
294 
295 using NSConstantArraySyntheticFrontEnd =
296     GenericNSArrayISyntheticFrontEnd<ConstantArray32, ConstantArray64, false>;
297 } // namespace ConstantArray
298 
299 class NSArray0SyntheticFrontEnd : public SyntheticChildrenFrontEnd {
300 public:
301   NSArray0SyntheticFrontEnd(lldb::ValueObjectSP valobj_sp);
302 
303   ~NSArray0SyntheticFrontEnd() override = default;
304 
305   size_t CalculateNumChildren() override;
306 
307   lldb::ValueObjectSP GetChildAtIndex(size_t idx) override;
308 
309   bool Update() override;
310 
311   bool MightHaveChildren() override;
312 
313   size_t GetIndexOfChildWithName(ConstString name) override;
314 };
315 
316 class NSArray1SyntheticFrontEnd : public SyntheticChildrenFrontEnd {
317 public:
318   NSArray1SyntheticFrontEnd(lldb::ValueObjectSP valobj_sp);
319 
320   ~NSArray1SyntheticFrontEnd() override = default;
321 
322   size_t CalculateNumChildren() override;
323 
324   lldb::ValueObjectSP GetChildAtIndex(size_t idx) override;
325 
326   bool Update() override;
327 
328   bool MightHaveChildren() override;
329 
330   size_t GetIndexOfChildWithName(ConstString name) override;
331 };
332 } // namespace formatters
333 } // namespace lldb_private
334 
335 bool lldb_private::formatters::NSArraySummaryProvider(
336     ValueObject &valobj, Stream &stream, const TypeSummaryOptions &options) {
337   static constexpr llvm::StringLiteral g_TypeHint("NSArray");
338 
339   ProcessSP process_sp = valobj.GetProcessSP();
340   if (!process_sp)
341     return false;
342 
343   ObjCLanguageRuntime *runtime = ObjCLanguageRuntime::Get(*process_sp);
344 
345   if (!runtime)
346     return false;
347 
348   ObjCLanguageRuntime::ClassDescriptorSP descriptor(
349       runtime->GetClassDescriptor(valobj));
350 
351   if (!descriptor || !descriptor->IsValid())
352     return false;
353 
354   uint32_t ptr_size = process_sp->GetAddressByteSize();
355 
356   lldb::addr_t valobj_addr = valobj.GetValueAsUnsigned(0);
357 
358   if (!valobj_addr)
359     return false;
360 
361   uint64_t value = 0;
362 
363   ConstString class_name(descriptor->GetClassName());
364 
365   static const ConstString g_NSArrayI("__NSArrayI");
366   static const ConstString g_NSArrayM("__NSArrayM");
367   static const ConstString g_NSArrayI_Transfer("__NSArrayI_Transfer");
368   static const ConstString g_NSFrozenArrayM("__NSFrozenArrayM");
369   static const ConstString g_NSArray0("__NSArray0");
370   static const ConstString g_NSArray1("__NSSingleObjectArrayI");
371   static const ConstString g_NSArrayCF("__NSCFArray");
372   static const ConstString g_NSArrayMLegacy("__NSArrayM_Legacy");
373   static const ConstString g_NSArrayMImmutable("__NSArrayM_Immutable");
374   static const ConstString g_NSCallStackArray("_NSCallStackArray");
375   static const ConstString g_NSConstantArray("NSConstantArray");
376 
377   if (class_name.IsEmpty())
378     return false;
379 
380   if (class_name == g_NSArrayI) {
381     Status error;
382     value = process_sp->ReadUnsignedIntegerFromMemory(valobj_addr + ptr_size,
383                                                       ptr_size, 0, error);
384     if (error.Fail())
385       return false;
386   } else if (class_name == g_NSConstantArray) {
387     Status error;
388     value = process_sp->ReadUnsignedIntegerFromMemory(valobj_addr + ptr_size, 8,
389                                                       0, error);
390     if (error.Fail())
391       return false;
392   } else if (class_name == g_NSArrayM) {
393     AppleObjCRuntime *apple_runtime =
394     llvm::dyn_cast_or_null<AppleObjCRuntime>(runtime);
395     Status error;
396     if (apple_runtime && apple_runtime->GetFoundationVersion() >= 1437) {
397       value = Foundation1437::__NSArrayMSize(*process_sp, valobj_addr, error);
398     } else {
399       value = process_sp->ReadUnsignedIntegerFromMemory(valobj_addr + ptr_size,
400                                                         ptr_size, 0, error);
401     }
402     if (error.Fail())
403       return false;
404   } else if (class_name == g_NSArrayI_Transfer) {
405     Status error;
406     value = process_sp->ReadUnsignedIntegerFromMemory(valobj_addr + ptr_size,
407                                                       ptr_size, 0, error);
408     if (error.Fail())
409       return false;
410   } else if (class_name == g_NSFrozenArrayM) {
411     Status error;
412     value = Foundation1436::__NSFrozenArrayMSize(*process_sp, valobj_addr, error);
413     if (error.Fail())
414       return false;
415   } else if (class_name == g_NSArrayMLegacy) {
416     Status error;
417     value = process_sp->ReadUnsignedIntegerFromMemory(valobj_addr + ptr_size,
418                                                       ptr_size, 0, error);
419     if (error.Fail())
420       return false;
421   } else if (class_name == g_NSArrayMImmutable) {
422     Status error;
423     value = process_sp->ReadUnsignedIntegerFromMemory(valobj_addr + ptr_size,
424                                                       ptr_size, 0, error);
425     if (error.Fail())
426       return false;
427   } else if (class_name == g_NSArray0) {
428     value = 0;
429   } else if (class_name == g_NSArray1) {
430     value = 1;
431   } else if (class_name == g_NSArrayCF || class_name == g_NSCallStackArray) {
432     // __NSCFArray and _NSCallStackArray store the number of elements as a
433     // pointer-sized value at offset `2 * ptr_size`.
434     Status error;
435     value = process_sp->ReadUnsignedIntegerFromMemory(
436         valobj_addr + 2 * ptr_size, ptr_size, 0, error);
437     if (error.Fail())
438       return false;
439   } else {
440     auto &map(NSArray_Additionals::GetAdditionalSummaries());
441     auto iter = map.find(class_name), end = map.end();
442     if (iter != end)
443       return iter->second(valobj, stream, options);
444     else
445       return false;
446   }
447 
448   llvm::StringRef prefix, suffix;
449   if (Language *language = Language::FindPlugin(options.GetLanguage()))
450     std::tie(prefix, suffix) = language->GetFormatterPrefixSuffix(g_TypeHint);
451 
452   stream << prefix;
453   stream.Printf("%" PRIu64 " %s%s", value, "element", value == 1 ? "" : "s");
454   stream << suffix;
455   return true;
456 }
457 
458 lldb_private::formatters::NSArrayMSyntheticFrontEndBase::
459     NSArrayMSyntheticFrontEndBase(lldb::ValueObjectSP valobj_sp)
460     : SyntheticChildrenFrontEnd(*valobj_sp), m_exe_ctx_ref(), m_id_type() {
461   if (valobj_sp) {
462     TypeSystemClangSP scratch_ts_sp = ScratchTypeSystemClang::GetForTarget(
463         *valobj_sp->GetExecutionContextRef().GetTargetSP());
464     if (scratch_ts_sp)
465       m_id_type = CompilerType(
466           scratch_ts_sp->weak_from_this(),
467           scratch_ts_sp->getASTContext().ObjCBuiltinIdTy.getAsOpaquePtr());
468     if (valobj_sp->GetProcessSP())
469       m_ptr_size = valobj_sp->GetProcessSP()->GetAddressByteSize();
470   }
471 }
472 
473 template <typename D32, typename D64>
474 lldb_private::formatters::
475   GenericNSArrayMSyntheticFrontEnd<D32, D64>::
476     GenericNSArrayMSyntheticFrontEnd(lldb::ValueObjectSP valobj_sp)
477     : NSArrayMSyntheticFrontEndBase(valobj_sp), m_data_32(nullptr),
478       m_data_64(nullptr) {}
479 
480 size_t
481 lldb_private::formatters::NSArrayMSyntheticFrontEndBase::CalculateNumChildren() {
482   return GetUsedCount();
483 }
484 
485 lldb::ValueObjectSP
486 lldb_private::formatters::NSArrayMSyntheticFrontEndBase::GetChildAtIndex(
487     size_t idx) {
488   if (idx >= CalculateNumChildren())
489     return lldb::ValueObjectSP();
490   lldb::addr_t object_at_idx = GetDataAddress();
491   size_t pyhs_idx = idx;
492   pyhs_idx += GetOffset();
493   if (GetSize() <= pyhs_idx)
494     pyhs_idx -= GetSize();
495   object_at_idx += (pyhs_idx * m_ptr_size);
496   StreamString idx_name;
497   idx_name.Printf("[%" PRIu64 "]", (uint64_t)idx);
498   return CreateValueObjectFromAddress(idx_name.GetString(), object_at_idx,
499                                       m_exe_ctx_ref, m_id_type);
500 }
501 
502 template <typename D32, typename D64>
503 bool
504 lldb_private::formatters::
505   GenericNSArrayMSyntheticFrontEnd<D32, D64>::Update() {
506   ValueObjectSP valobj_sp = m_backend.GetSP();
507   m_ptr_size = 0;
508   delete m_data_32;
509   m_data_32 = nullptr;
510   delete m_data_64;
511   m_data_64 = nullptr;
512   if (!valobj_sp)
513     return false;
514   m_exe_ctx_ref = valobj_sp->GetExecutionContextRef();
515   Status error;
516   error.Clear();
517   lldb::ProcessSP process_sp(valobj_sp->GetProcessSP());
518   if (!process_sp)
519     return false;
520   m_ptr_size = process_sp->GetAddressByteSize();
521   uint64_t data_location = valobj_sp->GetValueAsUnsigned(0) + m_ptr_size;
522   if (m_ptr_size == 4) {
523     m_data_32 = new D32();
524     process_sp->ReadMemory(data_location, m_data_32, sizeof(D32),
525                            error);
526   } else {
527     m_data_64 = new D64();
528     process_sp->ReadMemory(data_location, m_data_64, sizeof(D64),
529                            error);
530   }
531 
532   return error.Success();
533 }
534 
535 bool
536 lldb_private::formatters::NSArrayMSyntheticFrontEndBase::MightHaveChildren() {
537   return true;
538 }
539 
540 size_t
541 lldb_private::formatters::NSArrayMSyntheticFrontEndBase::GetIndexOfChildWithName(
542     ConstString name) {
543   const char *item_name = name.GetCString();
544   uint32_t idx = ExtractIndexFromString(item_name);
545   if (idx < UINT32_MAX && idx >= CalculateNumChildren())
546     return UINT32_MAX;
547   return idx;
548 }
549 
550 template <typename D32, typename D64>
551 lldb_private::formatters::
552   GenericNSArrayMSyntheticFrontEnd<D32, D64>::
553     ~GenericNSArrayMSyntheticFrontEnd<D32, D64>() {
554   delete m_data_32;
555   m_data_32 = nullptr;
556   delete m_data_64;
557   m_data_64 = nullptr;
558 }
559 
560 template <typename D32, typename D64>
561 lldb::addr_t
562 lldb_private::formatters::
563   GenericNSArrayMSyntheticFrontEnd<D32, D64>::
564     GenericNSArrayMSyntheticFrontEnd::GetDataAddress() {
565   if (!m_data_32 && !m_data_64)
566     return LLDB_INVALID_ADDRESS;
567   return m_data_32 ? m_data_32->_data : m_data_64->_data;
568 }
569 
570 template <typename D32, typename D64>
571 uint64_t
572 lldb_private::formatters::
573   GenericNSArrayMSyntheticFrontEnd<D32, D64>::
574     GenericNSArrayMSyntheticFrontEnd::GetUsedCount() {
575   if (!m_data_32 && !m_data_64)
576     return 0;
577   return m_data_32 ? m_data_32->_used : m_data_64->_used;
578 }
579 
580 template <typename D32, typename D64>
581 uint64_t
582 lldb_private::formatters::
583   GenericNSArrayMSyntheticFrontEnd<D32, D64>::
584     GenericNSArrayMSyntheticFrontEnd::GetOffset() {
585   if (!m_data_32 && !m_data_64)
586     return 0;
587   return m_data_32 ? m_data_32->_offset : m_data_64->_offset;
588 }
589 
590 template <typename D32, typename D64>
591 uint64_t
592 lldb_private::formatters::
593   GenericNSArrayMSyntheticFrontEnd<D32, D64>::
594     GenericNSArrayMSyntheticFrontEnd::GetSize() {
595   if (!m_data_32 && !m_data_64)
596     return 0;
597   return m_data_32 ? m_data_32->_size : m_data_64->_size;
598 }
599 
600 template <typename D32, typename D64, bool Inline>
601 lldb_private::formatters::GenericNSArrayISyntheticFrontEnd<D32, D64, Inline>::
602     GenericNSArrayISyntheticFrontEnd(lldb::ValueObjectSP valobj_sp)
603     : SyntheticChildrenFrontEnd(*valobj_sp), m_exe_ctx_ref(),
604       m_data_32(nullptr), m_data_64(nullptr) {
605   if (valobj_sp) {
606     CompilerType type = valobj_sp->GetCompilerType();
607     if (type) {
608       TypeSystemClangSP scratch_ts_sp = ScratchTypeSystemClang::GetForTarget(
609           *valobj_sp->GetExecutionContextRef().GetTargetSP());
610       if (scratch_ts_sp)
611         m_id_type = scratch_ts_sp->GetType(
612             scratch_ts_sp->getASTContext().ObjCBuiltinIdTy);
613     }
614   }
615 }
616 
617 template <typename D32, typename D64, bool Inline>
618 lldb_private::formatters::GenericNSArrayISyntheticFrontEnd<D32, D64, Inline>::
619   ~GenericNSArrayISyntheticFrontEnd<D32, D64, Inline>() {
620   delete m_data_32;
621   m_data_32 = nullptr;
622   delete m_data_64;
623   m_data_64 = nullptr;
624 }
625 
626 template <typename D32, typename D64, bool Inline>
627 size_t
628 lldb_private::formatters::GenericNSArrayISyntheticFrontEnd<D32, D64, Inline>::
629   GetIndexOfChildWithName(ConstString name) {
630   const char *item_name = name.GetCString();
631   uint32_t idx = ExtractIndexFromString(item_name);
632   if (idx < UINT32_MAX && idx >= CalculateNumChildren())
633     return UINT32_MAX;
634   return idx;
635 }
636 
637 template <typename D32, typename D64, bool Inline>
638 size_t
639 lldb_private::formatters::GenericNSArrayISyntheticFrontEnd<D32, D64, Inline>::
640   CalculateNumChildren() {
641   return m_data_32 ? m_data_32->used : m_data_64->used;
642 }
643 
644 template <typename D32, typename D64, bool Inline>
645 bool
646 lldb_private::formatters::GenericNSArrayISyntheticFrontEnd<D32, D64, Inline>::
647   Update() {
648   ValueObjectSP valobj_sp = m_backend.GetSP();
649   m_ptr_size = 0;
650   delete m_data_32;
651   m_data_32 = nullptr;
652   delete m_data_64;
653   m_data_64 = nullptr;
654   if (!valobj_sp)
655     return false;
656   m_exe_ctx_ref = valobj_sp->GetExecutionContextRef();
657   Status error;
658   error.Clear();
659   lldb::ProcessSP process_sp(valobj_sp->GetProcessSP());
660   if (!process_sp)
661     return false;
662   m_ptr_size = process_sp->GetAddressByteSize();
663   uint64_t data_location = valobj_sp->GetValueAsUnsigned(0) + m_ptr_size;
664   if (m_ptr_size == 4) {
665     m_data_32 = new D32();
666     process_sp->ReadMemory(data_location, m_data_32, sizeof(D32),
667                            error);
668   } else {
669     m_data_64 = new D64();
670     process_sp->ReadMemory(data_location, m_data_64, sizeof(D64),
671                            error);
672   }
673 
674   return error.Success();
675 }
676 
677 template <typename D32, typename D64, bool Inline>
678 bool
679 lldb_private::formatters::GenericNSArrayISyntheticFrontEnd<D32, D64, Inline>::
680   MightHaveChildren() {
681   return true;
682 }
683 
684 template <typename D32, typename D64, bool Inline>
685 lldb::ValueObjectSP
686 lldb_private::formatters::GenericNSArrayISyntheticFrontEnd<D32, D64, Inline>::
687   GetChildAtIndex(size_t idx) {
688   if (idx >= CalculateNumChildren())
689     return lldb::ValueObjectSP();
690   lldb::addr_t object_at_idx;
691   if (Inline) {
692     object_at_idx = m_backend.GetSP()->GetValueAsUnsigned(0) + m_ptr_size;
693     object_at_idx += m_ptr_size == 4 ? sizeof(D32) : sizeof(D64); // skip the data header
694     object_at_idx -= m_ptr_size; // we treat the last entry in the data header as the first pointer
695   } else {
696     object_at_idx = m_data_32 ? m_data_32->list : m_data_64->list;
697   }
698   object_at_idx += (idx * m_ptr_size);
699 
700   ProcessSP process_sp = m_exe_ctx_ref.GetProcessSP();
701   if (!process_sp)
702     return lldb::ValueObjectSP();
703   Status error;
704   if (error.Fail())
705     return lldb::ValueObjectSP();
706   StreamString idx_name;
707   idx_name.Printf("[%" PRIu64 "]", (uint64_t)idx);
708   return CreateValueObjectFromAddress(idx_name.GetString(), object_at_idx,
709                                       m_exe_ctx_ref, m_id_type);
710 }
711 
712 lldb_private::formatters::NSArray0SyntheticFrontEnd::NSArray0SyntheticFrontEnd(
713     lldb::ValueObjectSP valobj_sp)
714     : SyntheticChildrenFrontEnd(*valobj_sp) {}
715 
716 size_t
717 lldb_private::formatters::NSArray0SyntheticFrontEnd::GetIndexOfChildWithName(
718     ConstString name) {
719   return UINT32_MAX;
720 }
721 
722 size_t
723 lldb_private::formatters::NSArray0SyntheticFrontEnd::CalculateNumChildren() {
724   return 0;
725 }
726 
727 bool lldb_private::formatters::NSArray0SyntheticFrontEnd::Update() {
728   return false;
729 }
730 
731 bool lldb_private::formatters::NSArray0SyntheticFrontEnd::MightHaveChildren() {
732   return false;
733 }
734 
735 lldb::ValueObjectSP
736 lldb_private::formatters::NSArray0SyntheticFrontEnd::GetChildAtIndex(
737     size_t idx) {
738   return lldb::ValueObjectSP();
739 }
740 
741 lldb_private::formatters::NSArray1SyntheticFrontEnd::NSArray1SyntheticFrontEnd(
742     lldb::ValueObjectSP valobj_sp)
743     : SyntheticChildrenFrontEnd(*valobj_sp.get()) {}
744 
745 size_t
746 lldb_private::formatters::NSArray1SyntheticFrontEnd::GetIndexOfChildWithName(
747     ConstString name) {
748   static const ConstString g_zero("[0]");
749 
750   if (name == g_zero)
751     return 0;
752 
753   return UINT32_MAX;
754 }
755 
756 size_t
757 lldb_private::formatters::NSArray1SyntheticFrontEnd::CalculateNumChildren() {
758   return 1;
759 }
760 
761 bool lldb_private::formatters::NSArray1SyntheticFrontEnd::Update() {
762   return false;
763 }
764 
765 bool lldb_private::formatters::NSArray1SyntheticFrontEnd::MightHaveChildren() {
766   return true;
767 }
768 
769 lldb::ValueObjectSP
770 lldb_private::formatters::NSArray1SyntheticFrontEnd::GetChildAtIndex(
771     size_t idx) {
772   static const ConstString g_zero("[0]");
773 
774   if (idx == 0) {
775     TypeSystemClangSP scratch_ts_sp =
776         ScratchTypeSystemClang::GetForTarget(*m_backend.GetTargetSP());
777     if (scratch_ts_sp) {
778       CompilerType id_type(scratch_ts_sp->GetBasicType(lldb::eBasicTypeObjCID));
779       return m_backend.GetSyntheticChildAtOffset(
780           m_backend.GetProcessSP()->GetAddressByteSize(), id_type, true,
781           g_zero);
782     }
783   }
784   return lldb::ValueObjectSP();
785 }
786 
787 SyntheticChildrenFrontEnd *
788 lldb_private::formatters::NSArraySyntheticFrontEndCreator(
789     CXXSyntheticChildren *synth, lldb::ValueObjectSP valobj_sp) {
790   if (!valobj_sp)
791     return nullptr;
792 
793   lldb::ProcessSP process_sp(valobj_sp->GetProcessSP());
794   if (!process_sp)
795     return nullptr;
796   AppleObjCRuntime *runtime = llvm::dyn_cast_or_null<AppleObjCRuntime>(
797       ObjCLanguageRuntime::Get(*process_sp));
798   if (!runtime)
799     return nullptr;
800 
801   CompilerType valobj_type(valobj_sp->GetCompilerType());
802   Flags flags(valobj_type.GetTypeInfo());
803 
804   if (flags.IsClear(eTypeIsPointer)) {
805     Status error;
806     valobj_sp = valobj_sp->AddressOf(error);
807     if (error.Fail() || !valobj_sp)
808       return nullptr;
809   }
810 
811   ObjCLanguageRuntime::ClassDescriptorSP descriptor(
812       runtime->GetClassDescriptor(*valobj_sp));
813 
814   if (!descriptor || !descriptor->IsValid())
815     return nullptr;
816 
817   ConstString class_name(descriptor->GetClassName());
818 
819   static const ConstString g_NSArrayI("__NSArrayI");
820   static const ConstString g_NSConstantArray("NSConstantArray");
821   static const ConstString g_NSArrayI_Transfer("__NSArrayI_Transfer");
822   static const ConstString g_NSFrozenArrayM("__NSFrozenArrayM");
823   static const ConstString g_NSArrayM("__NSArrayM");
824   static const ConstString g_NSArray0("__NSArray0");
825   static const ConstString g_NSArray1("__NSSingleObjectArrayI");
826   static const ConstString g_NSArrayMLegacy("__NSArrayM_Legacy");
827   static const ConstString g_NSArrayMImmutable("__NSArrayM_Immutable");
828   static const ConstString g_NSCallStackArray("_NSCallStackArray");
829 
830   if (class_name.IsEmpty())
831     return nullptr;
832 
833   if (class_name == g_NSArrayI) {
834     if (runtime->GetFoundationVersion() >= 1436)
835       return (new Foundation1436::NSArrayISyntheticFrontEnd(valobj_sp));
836     if (runtime->GetFoundationVersion() >= 1430)
837       return (new Foundation1430::NSArrayISyntheticFrontEnd(valobj_sp));
838     return (new Foundation1300::NSArrayISyntheticFrontEnd(valobj_sp));
839   } else if (class_name == g_NSArrayI_Transfer) {
840       return (new Foundation1436::NSArrayI_TransferSyntheticFrontEnd(valobj_sp));
841   } else if (class_name == g_NSConstantArray) {
842     return new ConstantArray::NSConstantArraySyntheticFrontEnd(valobj_sp);
843   } else if (class_name == g_NSFrozenArrayM) {
844     return (new Foundation1436::NSFrozenArrayMSyntheticFrontEnd(valobj_sp));
845   } else if (class_name == g_NSArray0) {
846     return (new NSArray0SyntheticFrontEnd(valobj_sp));
847   } else if (class_name == g_NSArray1) {
848     return (new NSArray1SyntheticFrontEnd(valobj_sp));
849   } else if (class_name == g_NSArrayM) {
850     if (runtime->GetFoundationVersion() >= 1437)
851       return (new Foundation1437::NSArrayMSyntheticFrontEnd(valobj_sp));
852     if (runtime->GetFoundationVersion() >= 1428)
853       return (new Foundation1428::NSArrayMSyntheticFrontEnd(valobj_sp));
854     if (runtime->GetFoundationVersion() >= 1100)
855       return (new Foundation1010::NSArrayMSyntheticFrontEnd(valobj_sp));
856   } else if (class_name == g_NSCallStackArray) {
857     return (new CallStackArray::NSCallStackArraySyntheticFrontEnd(valobj_sp));
858   } else {
859     auto &map(NSArray_Additionals::GetAdditionalSynthetics());
860     auto iter = map.find(class_name), end = map.end();
861     if (iter != end)
862       return iter->second(synth, valobj_sp);
863   }
864 
865   return nullptr;
866 }
867