xref: /freebsd-src/contrib/llvm-project/lldb/source/Plugins/Language/ObjC/NSArray.cpp (revision 8cc087a1eee9ec1ca9f7ac1e63ad51bdb5a682eb)
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;
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;
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 ConstString 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   std::string prefix, suffix;
449   if (Language *language = Language::FindPlugin(options.GetLanguage())) {
450     if (!language->GetFormatterPrefixSuffix(valobj, g_TypeHint, prefix,
451                                             suffix)) {
452       prefix.clear();
453       suffix.clear();
454     }
455   }
456 
457   stream.Printf("%s%" PRIu64 " %s%s%s", prefix.c_str(), value, "element",
458                 value == 1 ? "" : "s", suffix.c_str());
459   return true;
460 }
461 
462 lldb_private::formatters::NSArrayMSyntheticFrontEndBase::NSArrayMSyntheticFrontEndBase(
463     lldb::ValueObjectSP valobj_sp)
464     : SyntheticChildrenFrontEnd(*valobj_sp), m_exe_ctx_ref(), m_ptr_size(8),
465       m_id_type() {
466   if (valobj_sp) {
467     auto *clang_ast_context = ScratchTypeSystemClang::GetForTarget(
468         *valobj_sp->GetExecutionContextRef().GetTargetSP());
469     if (clang_ast_context)
470       m_id_type = CompilerType(
471           clang_ast_context,
472           clang_ast_context->getASTContext().ObjCBuiltinIdTy.getAsOpaquePtr());
473     if (valobj_sp->GetProcessSP())
474       m_ptr_size = valobj_sp->GetProcessSP()->GetAddressByteSize();
475   }
476 }
477 
478 template <typename D32, typename D64>
479 lldb_private::formatters::
480   GenericNSArrayMSyntheticFrontEnd<D32, D64>::
481     GenericNSArrayMSyntheticFrontEnd(lldb::ValueObjectSP valobj_sp)
482     : NSArrayMSyntheticFrontEndBase(valobj_sp), m_data_32(nullptr),
483       m_data_64(nullptr) {}
484 
485 size_t
486 lldb_private::formatters::NSArrayMSyntheticFrontEndBase::CalculateNumChildren() {
487   return GetUsedCount();
488 }
489 
490 lldb::ValueObjectSP
491 lldb_private::formatters::NSArrayMSyntheticFrontEndBase::GetChildAtIndex(
492     size_t idx) {
493   if (idx >= CalculateNumChildren())
494     return lldb::ValueObjectSP();
495   lldb::addr_t object_at_idx = GetDataAddress();
496   size_t pyhs_idx = idx;
497   pyhs_idx += GetOffset();
498   if (GetSize() <= pyhs_idx)
499     pyhs_idx -= GetSize();
500   object_at_idx += (pyhs_idx * m_ptr_size);
501   StreamString idx_name;
502   idx_name.Printf("[%" PRIu64 "]", (uint64_t)idx);
503   return CreateValueObjectFromAddress(idx_name.GetString(), object_at_idx,
504                                       m_exe_ctx_ref, m_id_type);
505 }
506 
507 template <typename D32, typename D64>
508 bool
509 lldb_private::formatters::
510   GenericNSArrayMSyntheticFrontEnd<D32, D64>::Update() {
511   ValueObjectSP valobj_sp = m_backend.GetSP();
512   m_ptr_size = 0;
513   delete m_data_32;
514   m_data_32 = nullptr;
515   delete m_data_64;
516   m_data_64 = nullptr;
517   if (!valobj_sp)
518     return false;
519   m_exe_ctx_ref = valobj_sp->GetExecutionContextRef();
520   Status error;
521   error.Clear();
522   lldb::ProcessSP process_sp(valobj_sp->GetProcessSP());
523   if (!process_sp)
524     return false;
525   m_ptr_size = process_sp->GetAddressByteSize();
526   uint64_t data_location = valobj_sp->GetValueAsUnsigned(0) + m_ptr_size;
527   if (m_ptr_size == 4) {
528     m_data_32 = new D32();
529     process_sp->ReadMemory(data_location, m_data_32, sizeof(D32),
530                            error);
531   } else {
532     m_data_64 = new D64();
533     process_sp->ReadMemory(data_location, m_data_64, sizeof(D64),
534                            error);
535   }
536   if (error.Fail())
537     return false;
538   return false;
539 }
540 
541 bool
542 lldb_private::formatters::NSArrayMSyntheticFrontEndBase::MightHaveChildren() {
543   return true;
544 }
545 
546 size_t
547 lldb_private::formatters::NSArrayMSyntheticFrontEndBase::GetIndexOfChildWithName(
548     ConstString name) {
549   const char *item_name = name.GetCString();
550   uint32_t idx = ExtractIndexFromString(item_name);
551   if (idx < UINT32_MAX && idx >= CalculateNumChildren())
552     return UINT32_MAX;
553   return idx;
554 }
555 
556 template <typename D32, typename D64>
557 lldb_private::formatters::
558   GenericNSArrayMSyntheticFrontEnd<D32, D64>::
559     ~GenericNSArrayMSyntheticFrontEnd<D32, D64>() {
560   delete m_data_32;
561   m_data_32 = nullptr;
562   delete m_data_64;
563   m_data_64 = nullptr;
564 }
565 
566 template <typename D32, typename D64>
567 lldb::addr_t
568 lldb_private::formatters::
569   GenericNSArrayMSyntheticFrontEnd<D32, D64>::
570     GenericNSArrayMSyntheticFrontEnd::GetDataAddress() {
571   if (!m_data_32 && !m_data_64)
572     return LLDB_INVALID_ADDRESS;
573   return m_data_32 ? m_data_32->_data : m_data_64->_data;
574 }
575 
576 template <typename D32, typename D64>
577 uint64_t
578 lldb_private::formatters::
579   GenericNSArrayMSyntheticFrontEnd<D32, D64>::
580     GenericNSArrayMSyntheticFrontEnd::GetUsedCount() {
581   if (!m_data_32 && !m_data_64)
582     return 0;
583   return m_data_32 ? m_data_32->_used : m_data_64->_used;
584 }
585 
586 template <typename D32, typename D64>
587 uint64_t
588 lldb_private::formatters::
589   GenericNSArrayMSyntheticFrontEnd<D32, D64>::
590     GenericNSArrayMSyntheticFrontEnd::GetOffset() {
591   if (!m_data_32 && !m_data_64)
592     return 0;
593   return m_data_32 ? m_data_32->_offset : m_data_64->_offset;
594 }
595 
596 template <typename D32, typename D64>
597 uint64_t
598 lldb_private::formatters::
599   GenericNSArrayMSyntheticFrontEnd<D32, D64>::
600     GenericNSArrayMSyntheticFrontEnd::GetSize() {
601   if (!m_data_32 && !m_data_64)
602     return 0;
603   return m_data_32 ? m_data_32->_size : m_data_64->_size;
604 }
605 
606 template <typename D32, typename D64, bool Inline>
607 lldb_private::formatters::GenericNSArrayISyntheticFrontEnd<D32, D64, Inline>::
608   GenericNSArrayISyntheticFrontEnd(
609     lldb::ValueObjectSP valobj_sp)
610     : SyntheticChildrenFrontEnd(*valobj_sp), m_exe_ctx_ref(), m_ptr_size(8),
611       m_data_32(nullptr), m_data_64(nullptr) {
612   if (valobj_sp) {
613     CompilerType type = valobj_sp->GetCompilerType();
614     if (type) {
615       auto *clang_ast_context = ScratchTypeSystemClang::GetForTarget(
616           *valobj_sp->GetExecutionContextRef().GetTargetSP());
617       if (clang_ast_context)
618         m_id_type = clang_ast_context->GetType(
619             clang_ast_context->getASTContext().ObjCBuiltinIdTy);
620     }
621   }
622 }
623 
624 template <typename D32, typename D64, bool Inline>
625 lldb_private::formatters::GenericNSArrayISyntheticFrontEnd<D32, D64, Inline>::
626   ~GenericNSArrayISyntheticFrontEnd<D32, D64, Inline>() {
627   delete m_data_32;
628   m_data_32 = nullptr;
629   delete m_data_64;
630   m_data_64 = nullptr;
631 }
632 
633 template <typename D32, typename D64, bool Inline>
634 size_t
635 lldb_private::formatters::GenericNSArrayISyntheticFrontEnd<D32, D64, Inline>::
636   GetIndexOfChildWithName(ConstString name) {
637   const char *item_name = name.GetCString();
638   uint32_t idx = ExtractIndexFromString(item_name);
639   if (idx < UINT32_MAX && idx >= CalculateNumChildren())
640     return UINT32_MAX;
641   return idx;
642 }
643 
644 template <typename D32, typename D64, bool Inline>
645 size_t
646 lldb_private::formatters::GenericNSArrayISyntheticFrontEnd<D32, D64, Inline>::
647   CalculateNumChildren() {
648   return m_data_32 ? m_data_32->used : m_data_64->used;
649 }
650 
651 template <typename D32, typename D64, bool Inline>
652 bool
653 lldb_private::formatters::GenericNSArrayISyntheticFrontEnd<D32, D64, Inline>::
654   Update() {
655   ValueObjectSP valobj_sp = m_backend.GetSP();
656   m_ptr_size = 0;
657   delete m_data_32;
658   m_data_32 = nullptr;
659   delete m_data_64;
660   m_data_64 = nullptr;
661   if (!valobj_sp)
662     return false;
663   m_exe_ctx_ref = valobj_sp->GetExecutionContextRef();
664   Status error;
665   error.Clear();
666   lldb::ProcessSP process_sp(valobj_sp->GetProcessSP());
667   if (!process_sp)
668     return false;
669   m_ptr_size = process_sp->GetAddressByteSize();
670   uint64_t data_location = valobj_sp->GetValueAsUnsigned(0) + m_ptr_size;
671   if (m_ptr_size == 4) {
672     m_data_32 = new D32();
673     process_sp->ReadMemory(data_location, m_data_32, sizeof(D32),
674                            error);
675   } else {
676     m_data_64 = new D64();
677     process_sp->ReadMemory(data_location, m_data_64, sizeof(D64),
678                            error);
679   }
680   if (error.Fail())
681     return false;
682   return false;
683 }
684 
685 template <typename D32, typename D64, bool Inline>
686 bool
687 lldb_private::formatters::GenericNSArrayISyntheticFrontEnd<D32, D64, Inline>::
688   MightHaveChildren() {
689   return true;
690 }
691 
692 template <typename D32, typename D64, bool Inline>
693 lldb::ValueObjectSP
694 lldb_private::formatters::GenericNSArrayISyntheticFrontEnd<D32, D64, Inline>::
695   GetChildAtIndex(size_t idx) {
696   if (idx >= CalculateNumChildren())
697     return lldb::ValueObjectSP();
698   lldb::addr_t object_at_idx;
699   if (Inline) {
700     object_at_idx = m_backend.GetSP()->GetValueAsUnsigned(0) + m_ptr_size;
701     object_at_idx += m_ptr_size == 4 ? sizeof(D32) : sizeof(D64); // skip the data header
702     object_at_idx -= m_ptr_size; // we treat the last entry in the data header as the first pointer
703   } else {
704     object_at_idx = m_data_32 ? m_data_32->list : m_data_64->list;
705   }
706   object_at_idx += (idx * m_ptr_size);
707 
708   ProcessSP process_sp = m_exe_ctx_ref.GetProcessSP();
709   if (!process_sp)
710     return lldb::ValueObjectSP();
711   Status error;
712   if (error.Fail())
713     return lldb::ValueObjectSP();
714   StreamString idx_name;
715   idx_name.Printf("[%" PRIu64 "]", (uint64_t)idx);
716   return CreateValueObjectFromAddress(idx_name.GetString(), object_at_idx,
717                                       m_exe_ctx_ref, m_id_type);
718 }
719 
720 lldb_private::formatters::NSArray0SyntheticFrontEnd::NSArray0SyntheticFrontEnd(
721     lldb::ValueObjectSP valobj_sp)
722     : SyntheticChildrenFrontEnd(*valobj_sp) {}
723 
724 size_t
725 lldb_private::formatters::NSArray0SyntheticFrontEnd::GetIndexOfChildWithName(
726     ConstString name) {
727   return UINT32_MAX;
728 }
729 
730 size_t
731 lldb_private::formatters::NSArray0SyntheticFrontEnd::CalculateNumChildren() {
732   return 0;
733 }
734 
735 bool lldb_private::formatters::NSArray0SyntheticFrontEnd::Update() {
736   return false;
737 }
738 
739 bool lldb_private::formatters::NSArray0SyntheticFrontEnd::MightHaveChildren() {
740   return false;
741 }
742 
743 lldb::ValueObjectSP
744 lldb_private::formatters::NSArray0SyntheticFrontEnd::GetChildAtIndex(
745     size_t idx) {
746   return lldb::ValueObjectSP();
747 }
748 
749 lldb_private::formatters::NSArray1SyntheticFrontEnd::NSArray1SyntheticFrontEnd(
750     lldb::ValueObjectSP valobj_sp)
751     : SyntheticChildrenFrontEnd(*valobj_sp.get()) {}
752 
753 size_t
754 lldb_private::formatters::NSArray1SyntheticFrontEnd::GetIndexOfChildWithName(
755     ConstString name) {
756   static const ConstString g_zero("[0]");
757 
758   if (name == g_zero)
759     return 0;
760 
761   return UINT32_MAX;
762 }
763 
764 size_t
765 lldb_private::formatters::NSArray1SyntheticFrontEnd::CalculateNumChildren() {
766   return 1;
767 }
768 
769 bool lldb_private::formatters::NSArray1SyntheticFrontEnd::Update() {
770   return false;
771 }
772 
773 bool lldb_private::formatters::NSArray1SyntheticFrontEnd::MightHaveChildren() {
774   return true;
775 }
776 
777 lldb::ValueObjectSP
778 lldb_private::formatters::NSArray1SyntheticFrontEnd::GetChildAtIndex(
779     size_t idx) {
780   static const ConstString g_zero("[0]");
781 
782   if (idx == 0) {
783     auto *clang_ast_context =
784         ScratchTypeSystemClang::GetForTarget(*m_backend.GetTargetSP());
785     if (clang_ast_context) {
786       CompilerType id_type(
787           clang_ast_context->GetBasicType(lldb::eBasicTypeObjCID));
788       return m_backend.GetSyntheticChildAtOffset(
789           m_backend.GetProcessSP()->GetAddressByteSize(), id_type, true,
790           g_zero);
791     }
792   }
793   return lldb::ValueObjectSP();
794 }
795 
796 SyntheticChildrenFrontEnd *
797 lldb_private::formatters::NSArraySyntheticFrontEndCreator(
798     CXXSyntheticChildren *synth, lldb::ValueObjectSP valobj_sp) {
799   if (!valobj_sp)
800     return nullptr;
801 
802   lldb::ProcessSP process_sp(valobj_sp->GetProcessSP());
803   if (!process_sp)
804     return nullptr;
805   AppleObjCRuntime *runtime = llvm::dyn_cast_or_null<AppleObjCRuntime>(
806       ObjCLanguageRuntime::Get(*process_sp));
807   if (!runtime)
808     return nullptr;
809 
810   CompilerType valobj_type(valobj_sp->GetCompilerType());
811   Flags flags(valobj_type.GetTypeInfo());
812 
813   if (flags.IsClear(eTypeIsPointer)) {
814     Status error;
815     valobj_sp = valobj_sp->AddressOf(error);
816     if (error.Fail() || !valobj_sp)
817       return nullptr;
818   }
819 
820   ObjCLanguageRuntime::ClassDescriptorSP descriptor(
821       runtime->GetClassDescriptor(*valobj_sp));
822 
823   if (!descriptor || !descriptor->IsValid())
824     return nullptr;
825 
826   ConstString class_name(descriptor->GetClassName());
827 
828   static const ConstString g_NSArrayI("__NSArrayI");
829   static const ConstString g_NSConstantArray("NSConstantArray");
830   static const ConstString g_NSArrayI_Transfer("__NSArrayI_Transfer");
831   static const ConstString g_NSFrozenArrayM("__NSFrozenArrayM");
832   static const ConstString g_NSArrayM("__NSArrayM");
833   static const ConstString g_NSArray0("__NSArray0");
834   static const ConstString g_NSArray1("__NSSingleObjectArrayI");
835   static const ConstString g_NSArrayMLegacy("__NSArrayM_Legacy");
836   static const ConstString g_NSArrayMImmutable("__NSArrayM_Immutable");
837   static const ConstString g_NSCallStackArray("_NSCallStackArray");
838 
839   if (class_name.IsEmpty())
840     return nullptr;
841 
842   if (class_name == g_NSArrayI) {
843     if (runtime->GetFoundationVersion() >= 1436)
844       return (new Foundation1436::NSArrayISyntheticFrontEnd(valobj_sp));
845     if (runtime->GetFoundationVersion() >= 1430)
846       return (new Foundation1430::NSArrayISyntheticFrontEnd(valobj_sp));
847     return (new Foundation1300::NSArrayISyntheticFrontEnd(valobj_sp));
848   } else if (class_name == g_NSArrayI_Transfer) {
849       return (new Foundation1436::NSArrayI_TransferSyntheticFrontEnd(valobj_sp));
850   } else if (class_name == g_NSConstantArray) {
851     return new ConstantArray::NSConstantArraySyntheticFrontEnd(valobj_sp);
852   } else if (class_name == g_NSFrozenArrayM) {
853     return (new Foundation1436::NSFrozenArrayMSyntheticFrontEnd(valobj_sp));
854   } else if (class_name == g_NSArray0) {
855     return (new NSArray0SyntheticFrontEnd(valobj_sp));
856   } else if (class_name == g_NSArray1) {
857     return (new NSArray1SyntheticFrontEnd(valobj_sp));
858   } else if (class_name == g_NSArrayM) {
859     if (runtime->GetFoundationVersion() >= 1437)
860       return (new Foundation1437::NSArrayMSyntheticFrontEnd(valobj_sp));
861     if (runtime->GetFoundationVersion() >= 1428)
862       return (new Foundation1428::NSArrayMSyntheticFrontEnd(valobj_sp));
863     if (runtime->GetFoundationVersion() >= 1100)
864       return (new Foundation1010::NSArrayMSyntheticFrontEnd(valobj_sp));
865   } else if (class_name == g_NSCallStackArray) {
866     return (new CallStackArray::NSCallStackArraySyntheticFrontEnd(valobj_sp));
867   } else {
868     auto &map(NSArray_Additionals::GetAdditionalSynthetics());
869     auto iter = map.find(class_name), end = map.end();
870     if (iter != end)
871       return iter->second(synth, valobj_sp);
872   }
873 
874   return nullptr;
875 }
876