xref: /openbsd-src/gnu/llvm/lldb/source/Plugins/Language/CPlusPlus/LibCxx.cpp (revision 3d61058aa5c692477b6d18acfbbdb653a9930ff9) 
1 //===-- LibCxx.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 "LibCxx.h"
10 
11 #include "lldb/Core/Debugger.h"
12 #include "lldb/Core/FormatEntity.h"
13 #include "lldb/Core/ValueObject.h"
14 #include "lldb/Core/ValueObjectConstResult.h"
15 #include "lldb/DataFormatters/FormattersHelpers.h"
16 #include "lldb/DataFormatters/StringPrinter.h"
17 #include "lldb/DataFormatters/TypeSummary.h"
18 #include "lldb/DataFormatters/VectorIterator.h"
19 #include "lldb/Target/ProcessStructReader.h"
20 #include "lldb/Target/SectionLoadList.h"
21 #include "lldb/Target/Target.h"
22 #include "lldb/Utility/ConstString.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 #include "Plugins/LanguageRuntime/CPlusPlus/CPPLanguageRuntime.h"
29 #include "Plugins/TypeSystem/Clang/TypeSystemClang.h"
30 #include "lldb/lldb-enumerations.h"
31 #include <optional>
32 #include <tuple>
33 
34 using namespace lldb;
35 using namespace lldb_private;
36 using namespace lldb_private::formatters;
37 
38 lldb::ValueObjectSP lldb_private::formatters::GetChildMemberWithName(
39     ValueObject &obj, llvm::ArrayRef<ConstString> alternative_names) {
40   for (ConstString name : alternative_names) {
41     lldb::ValueObjectSP child_sp = obj.GetChildMemberWithName(name, true);
42 
43     if (child_sp)
44       return child_sp;
45   }
46   return {};
47 }
48 
49 bool lldb_private::formatters::LibcxxOptionalSummaryProvider(
50     ValueObject &valobj, Stream &stream, const TypeSummaryOptions &options) {
51   ValueObjectSP valobj_sp(valobj.GetNonSyntheticValue());
52   if (!valobj_sp)
53     return false;
54 
55   // An optional either contains a value or not, the member __engaged_ is
56   // a bool flag, it is true if the optional has a value and false otherwise.
57   ValueObjectSP engaged_sp(
58       valobj_sp->GetChildMemberWithName(ConstString("__engaged_"), true));
59 
60   if (!engaged_sp)
61     return false;
62 
63   llvm::StringRef engaged_as_cstring(
64       engaged_sp->GetValueAsUnsigned(0) == 1 ? "true" : "false");
65 
66   stream.Printf(" Has Value=%s ", engaged_as_cstring.data());
67 
68   return true;
69 }
70 
71 bool lldb_private::formatters::LibcxxFunctionSummaryProvider(
72     ValueObject &valobj, Stream &stream, const TypeSummaryOptions &options) {
73 
74   ValueObjectSP valobj_sp(valobj.GetNonSyntheticValue());
75 
76   if (!valobj_sp)
77     return false;
78 
79   ExecutionContext exe_ctx(valobj_sp->GetExecutionContextRef());
80   Process *process = exe_ctx.GetProcessPtr();
81 
82   if (process == nullptr)
83     return false;
84 
85   CPPLanguageRuntime *cpp_runtime = CPPLanguageRuntime::Get(*process);
86 
87   if (!cpp_runtime)
88     return false;
89 
90   CPPLanguageRuntime::LibCppStdFunctionCallableInfo callable_info =
91       cpp_runtime->FindLibCppStdFunctionCallableInfo(valobj_sp);
92 
93   switch (callable_info.callable_case) {
94   case CPPLanguageRuntime::LibCppStdFunctionCallableCase::Invalid:
95     stream.Printf(" __f_ = %" PRIu64, callable_info.member_f_pointer_value);
96     return false;
97     break;
98   case CPPLanguageRuntime::LibCppStdFunctionCallableCase::Lambda:
99     stream.Printf(
100         " Lambda in File %s at Line %u",
101         callable_info.callable_line_entry.file.GetFilename().GetCString(),
102         callable_info.callable_line_entry.line);
103     break;
104   case CPPLanguageRuntime::LibCppStdFunctionCallableCase::CallableObject:
105     stream.Printf(
106         " Function in File %s at Line %u",
107         callable_info.callable_line_entry.file.GetFilename().GetCString(),
108         callable_info.callable_line_entry.line);
109     break;
110   case CPPLanguageRuntime::LibCppStdFunctionCallableCase::FreeOrMemberFunction:
111     stream.Printf(" Function = %s ",
112                   callable_info.callable_symbol.GetName().GetCString());
113     break;
114   }
115 
116   return true;
117 }
118 
119 bool lldb_private::formatters::LibcxxSmartPointerSummaryProvider(
120     ValueObject &valobj, Stream &stream, const TypeSummaryOptions &options) {
121   ValueObjectSP valobj_sp(valobj.GetNonSyntheticValue());
122   if (!valobj_sp)
123     return false;
124   ValueObjectSP ptr_sp(
125       valobj_sp->GetChildMemberWithName(ConstString("__ptr_"), true));
126   ValueObjectSP count_sp(valobj_sp->GetChildAtNamePath(
127       {ConstString("__cntrl_"), ConstString("__shared_owners_")}));
128   ValueObjectSP weakcount_sp(valobj_sp->GetChildAtNamePath(
129       {ConstString("__cntrl_"), ConstString("__shared_weak_owners_")}));
130 
131   if (!ptr_sp)
132     return false;
133 
134   if (ptr_sp->GetValueAsUnsigned(0) == 0) {
135     stream.Printf("nullptr");
136     return true;
137   } else {
138     bool print_pointee = false;
139     Status error;
140     ValueObjectSP pointee_sp = ptr_sp->Dereference(error);
141     if (pointee_sp && error.Success()) {
142       if (pointee_sp->DumpPrintableRepresentation(
143               stream, ValueObject::eValueObjectRepresentationStyleSummary,
144               lldb::eFormatInvalid,
145               ValueObject::PrintableRepresentationSpecialCases::eDisable,
146               false))
147         print_pointee = true;
148     }
149     if (!print_pointee)
150       stream.Printf("ptr = 0x%" PRIx64, ptr_sp->GetValueAsUnsigned(0));
151   }
152 
153   if (count_sp)
154     stream.Printf(" strong=%" PRIu64, 1 + count_sp->GetValueAsUnsigned(0));
155 
156   if (weakcount_sp)
157     stream.Printf(" weak=%" PRIu64, 1 + weakcount_sp->GetValueAsUnsigned(0));
158 
159   return true;
160 }
161 
162 bool lldb_private::formatters::LibcxxUniquePointerSummaryProvider(
163     ValueObject &valobj, Stream &stream, const TypeSummaryOptions &options) {
164   ValueObjectSP valobj_sp(valobj.GetNonSyntheticValue());
165   if (!valobj_sp)
166     return false;
167 
168   ValueObjectSP ptr_sp(
169       valobj_sp->GetChildMemberWithName(ConstString("__ptr_"), true));
170   if (!ptr_sp)
171     return false;
172 
173   ptr_sp = GetValueOfLibCXXCompressedPair(*ptr_sp);
174   if (!ptr_sp)
175     return false;
176 
177   if (ptr_sp->GetValueAsUnsigned(0) == 0) {
178     stream.Printf("nullptr");
179     return true;
180   } else {
181     bool print_pointee = false;
182     Status error;
183     ValueObjectSP pointee_sp = ptr_sp->Dereference(error);
184     if (pointee_sp && error.Success()) {
185       if (pointee_sp->DumpPrintableRepresentation(
186               stream, ValueObject::eValueObjectRepresentationStyleSummary,
187               lldb::eFormatInvalid,
188               ValueObject::PrintableRepresentationSpecialCases::eDisable,
189               false))
190         print_pointee = true;
191     }
192     if (!print_pointee)
193       stream.Printf("ptr = 0x%" PRIx64, ptr_sp->GetValueAsUnsigned(0));
194   }
195 
196   return true;
197 }
198 
199 /*
200  (lldb) fr var ibeg --raw --ptr-depth 1
201  (std::__1::__map_iterator<std::__1::__tree_iterator<std::__1::pair<int,
202  std::__1::basic_string<char, std::__1::char_traits<char>,
203  std::__1::allocator<char> > >, std::__1::__tree_node<std::__1::pair<int,
204  std::__1::basic_string<char, std::__1::char_traits<char>,
205  std::__1::allocator<char> > >, void *> *, long> >) ibeg = {
206  __i_ = {
207  __ptr_ = 0x0000000100103870 {
208  std::__1::__tree_node_base<void *> = {
209  std::__1::__tree_end_node<std::__1::__tree_node_base<void *> *> = {
210  __left_ = 0x0000000000000000
211  }
212  __right_ = 0x0000000000000000
213  __parent_ = 0x00000001001038b0
214  __is_black_ = true
215  }
216  __value_ = {
217  first = 0
218  second = { std::string }
219  */
220 
221 lldb_private::formatters::LibCxxMapIteratorSyntheticFrontEnd::
222     LibCxxMapIteratorSyntheticFrontEnd(lldb::ValueObjectSP valobj_sp)
223     : SyntheticChildrenFrontEnd(*valobj_sp), m_pair_ptr(), m_pair_sp() {
224   if (valobj_sp)
225     Update();
226 }
227 
228 bool lldb_private::formatters::LibCxxMapIteratorSyntheticFrontEnd::Update() {
229   m_pair_sp.reset();
230   m_pair_ptr = nullptr;
231 
232   ValueObjectSP valobj_sp = m_backend.GetSP();
233   if (!valobj_sp)
234     return false;
235 
236   TargetSP target_sp(valobj_sp->GetTargetSP());
237 
238   if (!target_sp)
239     return false;
240 
241   if (!valobj_sp)
242     return false;
243 
244   static ConstString g_i_("__i_");
245 
246   // this must be a ValueObject* because it is a child of the ValueObject we
247   // are producing children for it if were a ValueObjectSP, we would end up
248   // with a loop (iterator -> synthetic -> child -> parent == iterator) and
249   // that would in turn leak memory by never allowing the ValueObjects to die
250   // and free their memory
251   m_pair_ptr = valobj_sp
252                    ->GetValueForExpressionPath(
253                        ".__i_.__ptr_->__value_", nullptr, nullptr,
254                        ValueObject::GetValueForExpressionPathOptions()
255                            .DontCheckDotVsArrowSyntax()
256                            .SetSyntheticChildrenTraversal(
257                                ValueObject::GetValueForExpressionPathOptions::
258                                    SyntheticChildrenTraversal::None),
259                        nullptr)
260                    .get();
261 
262   if (!m_pair_ptr) {
263     m_pair_ptr = valobj_sp
264                      ->GetValueForExpressionPath(
265                          ".__i_.__ptr_", nullptr, nullptr,
266                          ValueObject::GetValueForExpressionPathOptions()
267                              .DontCheckDotVsArrowSyntax()
268                              .SetSyntheticChildrenTraversal(
269                                  ValueObject::GetValueForExpressionPathOptions::
270                                      SyntheticChildrenTraversal::None),
271                          nullptr)
272                      .get();
273     if (m_pair_ptr) {
274       auto __i_(valobj_sp->GetChildMemberWithName(g_i_, true));
275       if (!__i_) {
276         m_pair_ptr = nullptr;
277         return false;
278       }
279       CompilerType pair_type(
280           __i_->GetCompilerType().GetTypeTemplateArgument(0));
281       std::string name;
282       uint64_t bit_offset_ptr;
283       uint32_t bitfield_bit_size_ptr;
284       bool is_bitfield_ptr;
285       pair_type = pair_type.GetFieldAtIndex(
286           0, name, &bit_offset_ptr, &bitfield_bit_size_ptr, &is_bitfield_ptr);
287       if (!pair_type) {
288         m_pair_ptr = nullptr;
289         return false;
290       }
291 
292       auto addr(m_pair_ptr->GetValueAsUnsigned(LLDB_INVALID_ADDRESS));
293       m_pair_ptr = nullptr;
294       if (addr && addr != LLDB_INVALID_ADDRESS) {
295         auto ts = pair_type.GetTypeSystem();
296         auto ast_ctx = ts.dyn_cast_or_null<TypeSystemClang>();
297         if (!ast_ctx)
298           return false;
299 
300         // Mimick layout of std::__tree_iterator::__ptr_ and read it in
301         // from process memory.
302         //
303         // The following shows the contiguous block of memory:
304         //
305         //        +-----------------------------+ class __tree_end_node
306         // __ptr_ | pointer __left_;            |
307         //        +-----------------------------+ class __tree_node_base
308         //        | pointer __right_;           |
309         //        | __parent_pointer __parent_; |
310         //        | bool __is_black_;           |
311         //        +-----------------------------+ class __tree_node
312         //        | __node_value_type __value_; | <<< our key/value pair
313         //        +-----------------------------+
314         //
315         CompilerType tree_node_type = ast_ctx->CreateStructForIdentifier(
316             ConstString(),
317             {{"ptr0",
318               ast_ctx->GetBasicType(lldb::eBasicTypeVoid).GetPointerType()},
319              {"ptr1",
320               ast_ctx->GetBasicType(lldb::eBasicTypeVoid).GetPointerType()},
321              {"ptr2",
322               ast_ctx->GetBasicType(lldb::eBasicTypeVoid).GetPointerType()},
323              {"cw", ast_ctx->GetBasicType(lldb::eBasicTypeBool)},
324              {"payload", pair_type}});
325         std::optional<uint64_t> size = tree_node_type.GetByteSize(nullptr);
326         if (!size)
327           return false;
328         WritableDataBufferSP buffer_sp(new DataBufferHeap(*size, 0));
329         ProcessSP process_sp(target_sp->GetProcessSP());
330         Status error;
331         process_sp->ReadMemory(addr, buffer_sp->GetBytes(),
332                                buffer_sp->GetByteSize(), error);
333         if (error.Fail())
334           return false;
335         DataExtractor extractor(buffer_sp, process_sp->GetByteOrder(),
336                                 process_sp->GetAddressByteSize());
337         auto pair_sp = CreateValueObjectFromData(
338             "pair", extractor, valobj_sp->GetExecutionContextRef(),
339             tree_node_type);
340         if (pair_sp)
341           m_pair_sp = pair_sp->GetChildAtIndex(4, true);
342       }
343     }
344   }
345 
346   return false;
347 }
348 
349 size_t lldb_private::formatters::LibCxxMapIteratorSyntheticFrontEnd::
350     CalculateNumChildren() {
351   return 2;
352 }
353 
354 lldb::ValueObjectSP
355 lldb_private::formatters::LibCxxMapIteratorSyntheticFrontEnd::GetChildAtIndex(
356     size_t idx) {
357   if (m_pair_ptr)
358     return m_pair_ptr->GetChildAtIndex(idx, true);
359   if (m_pair_sp)
360     return m_pair_sp->GetChildAtIndex(idx, true);
361   return lldb::ValueObjectSP();
362 }
363 
364 bool lldb_private::formatters::LibCxxMapIteratorSyntheticFrontEnd::
365     MightHaveChildren() {
366   return true;
367 }
368 
369 size_t lldb_private::formatters::LibCxxMapIteratorSyntheticFrontEnd::
370     GetIndexOfChildWithName(ConstString name) {
371   if (name == "first")
372     return 0;
373   if (name == "second")
374     return 1;
375   return UINT32_MAX;
376 }
377 
378 lldb_private::formatters::LibCxxMapIteratorSyntheticFrontEnd::
379     ~LibCxxMapIteratorSyntheticFrontEnd() {
380   // this will be deleted when its parent dies (since it's a child object)
381   // delete m_pair_ptr;
382 }
383 
384 SyntheticChildrenFrontEnd *
385 lldb_private::formatters::LibCxxMapIteratorSyntheticFrontEndCreator(
386     CXXSyntheticChildren *, lldb::ValueObjectSP valobj_sp) {
387   return (valobj_sp ? new LibCxxMapIteratorSyntheticFrontEnd(valobj_sp)
388                     : nullptr);
389 }
390 
391 lldb_private::formatters::LibCxxUnorderedMapIteratorSyntheticFrontEnd::
392     LibCxxUnorderedMapIteratorSyntheticFrontEnd(lldb::ValueObjectSP valobj_sp)
393     : SyntheticChildrenFrontEnd(*valobj_sp) {
394   if (valobj_sp)
395     Update();
396 }
397 
398 bool lldb_private::formatters::LibCxxUnorderedMapIteratorSyntheticFrontEnd::
399     Update() {
400   m_pair_sp.reset();
401   m_iter_ptr = nullptr;
402 
403   ValueObjectSP valobj_sp = m_backend.GetSP();
404   if (!valobj_sp)
405     return false;
406 
407   TargetSP target_sp(valobj_sp->GetTargetSP());
408 
409   if (!target_sp)
410     return false;
411 
412   if (!valobj_sp)
413     return false;
414 
415   auto exprPathOptions = ValueObject::GetValueForExpressionPathOptions()
416                              .DontCheckDotVsArrowSyntax()
417                              .SetSyntheticChildrenTraversal(
418                                  ValueObject::GetValueForExpressionPathOptions::
419                                      SyntheticChildrenTraversal::None);
420 
421   // This must be a ValueObject* because it is a child of the ValueObject we
422   // are producing children for it if were a ValueObjectSP, we would end up
423   // with a loop (iterator -> synthetic -> child -> parent == iterator) and
424   // that would in turn leak memory by never allowing the ValueObjects to die
425   // and free their memory.
426   m_iter_ptr =
427       valobj_sp
428           ->GetValueForExpressionPath(".__i_.__node_", nullptr, nullptr,
429                                       exprPathOptions, nullptr)
430           .get();
431 
432   if (m_iter_ptr) {
433     auto iter_child(
434         valobj_sp->GetChildMemberWithName(ConstString("__i_"), true));
435     if (!iter_child) {
436       m_iter_ptr = nullptr;
437       return false;
438     }
439 
440     CompilerType node_type(iter_child->GetCompilerType()
441                                .GetTypeTemplateArgument(0)
442                                .GetPointeeType());
443 
444     CompilerType pair_type(node_type.GetTypeTemplateArgument(0));
445 
446     std::string name;
447     uint64_t bit_offset_ptr;
448     uint32_t bitfield_bit_size_ptr;
449     bool is_bitfield_ptr;
450 
451     pair_type = pair_type.GetFieldAtIndex(
452         0, name, &bit_offset_ptr, &bitfield_bit_size_ptr, &is_bitfield_ptr);
453     if (!pair_type) {
454       m_iter_ptr = nullptr;
455       return false;
456     }
457 
458     uint64_t addr = m_iter_ptr->GetValueAsUnsigned(LLDB_INVALID_ADDRESS);
459     m_iter_ptr = nullptr;
460 
461     if (addr == 0 || addr == LLDB_INVALID_ADDRESS)
462       return false;
463 
464     auto ts = pair_type.GetTypeSystem();
465     auto ast_ctx = ts.dyn_cast_or_null<TypeSystemClang>();
466     if (!ast_ctx)
467       return false;
468 
469     // Mimick layout of std::__hash_iterator::__node_ and read it in
470     // from process memory.
471     //
472     // The following shows the contiguous block of memory:
473     //
474     //         +-----------------------------+ class __hash_node_base
475     // __node_ | __next_pointer __next_;     |
476     //         +-----------------------------+ class __hash_node
477     //         | size_t __hash_;             |
478     //         | __node_value_type __value_; | <<< our key/value pair
479     //         +-----------------------------+
480     //
481     CompilerType tree_node_type = ast_ctx->CreateStructForIdentifier(
482         ConstString(),
483         {{"__next_",
484           ast_ctx->GetBasicType(lldb::eBasicTypeVoid).GetPointerType()},
485          {"__hash_", ast_ctx->GetBasicType(lldb::eBasicTypeUnsignedLongLong)},
486          {"__value_", pair_type}});
487     std::optional<uint64_t> size = tree_node_type.GetByteSize(nullptr);
488     if (!size)
489       return false;
490     WritableDataBufferSP buffer_sp(new DataBufferHeap(*size, 0));
491     ProcessSP process_sp(target_sp->GetProcessSP());
492     Status error;
493     process_sp->ReadMemory(addr, buffer_sp->GetBytes(),
494                            buffer_sp->GetByteSize(), error);
495     if (error.Fail())
496       return false;
497     DataExtractor extractor(buffer_sp, process_sp->GetByteOrder(),
498                             process_sp->GetAddressByteSize());
499     auto pair_sp = CreateValueObjectFromData(
500         "pair", extractor, valobj_sp->GetExecutionContextRef(), tree_node_type);
501     if (pair_sp)
502       m_pair_sp = pair_sp->GetChildAtIndex(2, true);
503   }
504 
505   return false;
506 }
507 
508 size_t lldb_private::formatters::LibCxxUnorderedMapIteratorSyntheticFrontEnd::
509     CalculateNumChildren() {
510   return 2;
511 }
512 
513 lldb::ValueObjectSP lldb_private::formatters::
514     LibCxxUnorderedMapIteratorSyntheticFrontEnd::GetChildAtIndex(size_t idx) {
515   if (m_pair_sp)
516     return m_pair_sp->GetChildAtIndex(idx, true);
517   return lldb::ValueObjectSP();
518 }
519 
520 bool lldb_private::formatters::LibCxxUnorderedMapIteratorSyntheticFrontEnd::
521     MightHaveChildren() {
522   return true;
523 }
524 
525 size_t lldb_private::formatters::LibCxxUnorderedMapIteratorSyntheticFrontEnd::
526     GetIndexOfChildWithName(ConstString name) {
527   if (name == "first")
528     return 0;
529   if (name == "second")
530     return 1;
531   return UINT32_MAX;
532 }
533 
534 SyntheticChildrenFrontEnd *
535 lldb_private::formatters::LibCxxUnorderedMapIteratorSyntheticFrontEndCreator(
536     CXXSyntheticChildren *, lldb::ValueObjectSP valobj_sp) {
537   return (valobj_sp ? new LibCxxUnorderedMapIteratorSyntheticFrontEnd(valobj_sp)
538                     : nullptr);
539 }
540 
541 /*
542  (lldb) fr var ibeg --raw --ptr-depth 1 -T
543  (std::__1::__wrap_iter<int *>) ibeg = {
544  (std::__1::__wrap_iter<int *>::iterator_type) __i = 0x00000001001037a0 {
545  (int) *__i = 1
546  }
547  }
548 */
549 
550 SyntheticChildrenFrontEnd *
551 lldb_private::formatters::LibCxxVectorIteratorSyntheticFrontEndCreator(
552     CXXSyntheticChildren *, lldb::ValueObjectSP valobj_sp) {
553   return (valobj_sp ? new VectorIteratorSyntheticFrontEnd(
554                           valobj_sp, {ConstString("__i_"), ConstString("__i")})
555                     : nullptr);
556 }
557 
558 lldb_private::formatters::LibcxxSharedPtrSyntheticFrontEnd::
559     LibcxxSharedPtrSyntheticFrontEnd(lldb::ValueObjectSP valobj_sp)
560     : SyntheticChildrenFrontEnd(*valobj_sp), m_cntrl(nullptr) {
561   if (valobj_sp)
562     Update();
563 }
564 
565 size_t lldb_private::formatters::LibcxxSharedPtrSyntheticFrontEnd::
566     CalculateNumChildren() {
567   return (m_cntrl ? 1 : 0);
568 }
569 
570 lldb::ValueObjectSP
571 lldb_private::formatters::LibcxxSharedPtrSyntheticFrontEnd::GetChildAtIndex(
572     size_t idx) {
573   if (!m_cntrl)
574     return lldb::ValueObjectSP();
575 
576   ValueObjectSP valobj_sp = m_backend.GetSP();
577   if (!valobj_sp)
578     return lldb::ValueObjectSP();
579 
580   if (idx == 0)
581     return valobj_sp->GetChildMemberWithName(ConstString("__ptr_"), true);
582 
583   if (idx == 1) {
584     if (auto ptr_sp =
585             valobj_sp->GetChildMemberWithName(ConstString("__ptr_"), true)) {
586       Status status;
587       auto value_sp = ptr_sp->Dereference(status);
588       if (status.Success()) {
589         auto value_type_sp =
590             valobj_sp->GetCompilerType().GetTypeTemplateArgument(0);
591         return value_sp->Cast(value_type_sp);
592       }
593     }
594   }
595 
596   return lldb::ValueObjectSP();
597 }
598 
599 bool lldb_private::formatters::LibcxxSharedPtrSyntheticFrontEnd::Update() {
600   m_cntrl = nullptr;
601 
602   ValueObjectSP valobj_sp = m_backend.GetSP();
603   if (!valobj_sp)
604     return false;
605 
606   TargetSP target_sp(valobj_sp->GetTargetSP());
607   if (!target_sp)
608     return false;
609 
610   lldb::ValueObjectSP cntrl_sp(
611       valobj_sp->GetChildMemberWithName(ConstString("__cntrl_"), true));
612 
613   m_cntrl = cntrl_sp.get(); // need to store the raw pointer to avoid a circular
614                             // dependency
615   return false;
616 }
617 
618 bool lldb_private::formatters::LibcxxSharedPtrSyntheticFrontEnd::
619     MightHaveChildren() {
620   return true;
621 }
622 
623 size_t lldb_private::formatters::LibcxxSharedPtrSyntheticFrontEnd::
624     GetIndexOfChildWithName(ConstString name) {
625   if (name == "__ptr_")
626     return 0;
627   if (name == "$$dereference$$")
628     return 1;
629   return UINT32_MAX;
630 }
631 
632 lldb_private::formatters::LibcxxSharedPtrSyntheticFrontEnd::
633     ~LibcxxSharedPtrSyntheticFrontEnd() = default;
634 
635 SyntheticChildrenFrontEnd *
636 lldb_private::formatters::LibcxxSharedPtrSyntheticFrontEndCreator(
637     CXXSyntheticChildren *, lldb::ValueObjectSP valobj_sp) {
638   return (valobj_sp ? new LibcxxSharedPtrSyntheticFrontEnd(valobj_sp)
639                     : nullptr);
640 }
641 
642 lldb_private::formatters::LibcxxUniquePtrSyntheticFrontEnd::
643     LibcxxUniquePtrSyntheticFrontEnd(lldb::ValueObjectSP valobj_sp)
644     : SyntheticChildrenFrontEnd(*valobj_sp) {
645   if (valobj_sp)
646     Update();
647 }
648 
649 lldb_private::formatters::LibcxxUniquePtrSyntheticFrontEnd::
650     ~LibcxxUniquePtrSyntheticFrontEnd() = default;
651 
652 SyntheticChildrenFrontEnd *
653 lldb_private::formatters::LibcxxUniquePtrSyntheticFrontEndCreator(
654     CXXSyntheticChildren *, lldb::ValueObjectSP valobj_sp) {
655   return (valobj_sp ? new LibcxxUniquePtrSyntheticFrontEnd(valobj_sp)
656                     : nullptr);
657 }
658 
659 size_t lldb_private::formatters::LibcxxUniquePtrSyntheticFrontEnd::
660     CalculateNumChildren() {
661   return (m_value_ptr_sp ? 1 : 0);
662 }
663 
664 lldb::ValueObjectSP
665 lldb_private::formatters::LibcxxUniquePtrSyntheticFrontEnd::GetChildAtIndex(
666     size_t idx) {
667   if (!m_value_ptr_sp)
668     return lldb::ValueObjectSP();
669 
670   if (idx == 0)
671     return m_value_ptr_sp;
672 
673   if (idx == 1) {
674     Status status;
675     auto value_sp = m_value_ptr_sp->Dereference(status);
676     if (status.Success()) {
677       return value_sp;
678     }
679   }
680 
681   return lldb::ValueObjectSP();
682 }
683 
684 bool lldb_private::formatters::LibcxxUniquePtrSyntheticFrontEnd::Update() {
685   ValueObjectSP valobj_sp = m_backend.GetSP();
686   if (!valobj_sp)
687     return false;
688 
689   ValueObjectSP ptr_sp(
690       valobj_sp->GetChildMemberWithName(ConstString("__ptr_"), true));
691   if (!ptr_sp)
692     return false;
693 
694   m_value_ptr_sp = GetValueOfLibCXXCompressedPair(*ptr_sp);
695 
696   return false;
697 }
698 
699 bool lldb_private::formatters::LibcxxUniquePtrSyntheticFrontEnd::
700     MightHaveChildren() {
701   return true;
702 }
703 
704 size_t lldb_private::formatters::LibcxxUniquePtrSyntheticFrontEnd::
705     GetIndexOfChildWithName(ConstString name) {
706   if (name == "__value_")
707     return 0;
708   if (name == "$$dereference$$")
709     return 1;
710   return UINT32_MAX;
711 }
712 
713 bool lldb_private::formatters::LibcxxContainerSummaryProvider(
714     ValueObject &valobj, Stream &stream, const TypeSummaryOptions &options) {
715   if (valobj.IsPointerType()) {
716     uint64_t value = valobj.GetValueAsUnsigned(0);
717     if (!value)
718       return false;
719     stream.Printf("0x%016" PRIx64 " ", value);
720   }
721   return FormatEntity::FormatStringRef("size=${svar%#}", stream, nullptr,
722                                        nullptr, nullptr, &valobj, false, false);
723 }
724 
725 /// The field layout in a libc++ string (cap, side, data or data, size, cap).
726 namespace {
727 enum class StringLayout { CSD, DSC };
728 }
729 
730 /// Determine the size in bytes of \p valobj (a libc++ std::string object) and
731 /// extract its data payload. Return the size + payload pair.
732 // TODO: Support big-endian architectures.
733 static std::optional<std::pair<uint64_t, ValueObjectSP>>
734 ExtractLibcxxStringInfo(ValueObject &valobj) {
735   ValueObjectSP valobj_r_sp =
736       valobj.GetChildMemberWithName(ConstString("__r_"), /*can_create=*/true);
737   if (!valobj_r_sp || !valobj_r_sp->GetError().Success())
738     return {};
739 
740   // __r_ is a compressed_pair of the actual data and the allocator. The data we
741   // want is in the first base class.
742   ValueObjectSP valobj_r_base_sp =
743       valobj_r_sp->GetChildAtIndex(0, /*can_create=*/true);
744   if (!valobj_r_base_sp)
745     return {};
746 
747   ValueObjectSP valobj_rep_sp = valobj_r_base_sp->GetChildMemberWithName(
748       ConstString("__value_"), /*can_create=*/true);
749   if (!valobj_rep_sp)
750     return {};
751 
752   ValueObjectSP l = valobj_rep_sp->GetChildMemberWithName(ConstString("__l"),
753                                                           /*can_create=*/true);
754   if (!l)
755     return {};
756 
757   StringLayout layout = l->GetIndexOfChildWithName(ConstString("__data_")) == 0
758                             ? StringLayout::DSC
759                             : StringLayout::CSD;
760 
761   bool short_mode = false; // this means the string is in short-mode and the
762                            // data is stored inline
763   bool using_bitmasks = true; // Whether the class uses bitmasks for the mode
764                               // flag (pre-D123580).
765   uint64_t size;
766   uint64_t size_mode_value = 0;
767 
768   ValueObjectSP short_sp = valobj_rep_sp->GetChildMemberWithName(
769       ConstString("__s"), /*can_create=*/true);
770   if (!short_sp)
771     return {};
772 
773   ValueObjectSP is_long =
774       short_sp->GetChildMemberWithName(ConstString("__is_long_"), true);
775   ValueObjectSP size_sp =
776       short_sp->GetChildAtNamePath({ConstString("__size_")});
777   if (!size_sp)
778     return {};
779 
780   if (is_long) {
781     using_bitmasks = false;
782     short_mode = !is_long->GetValueAsUnsigned(/*fail_value=*/0);
783     size = size_sp->GetValueAsUnsigned(/*fail_value=*/0);
784   } else {
785     // The string mode is encoded in the size field.
786     size_mode_value = size_sp->GetValueAsUnsigned(0);
787     uint8_t mode_mask = layout == StringLayout::DSC ? 0x80 : 1;
788     short_mode = (size_mode_value & mode_mask) == 0;
789   }
790 
791   if (short_mode) {
792     ValueObjectSP location_sp =
793         short_sp->GetChildMemberWithName(ConstString("__data_"), true);
794     if (using_bitmasks)
795       size = (layout == StringLayout::DSC) ? size_mode_value
796                                            : ((size_mode_value >> 1) % 256);
797 
798     // When the small-string optimization takes place, the data must fit in the
799     // inline string buffer (23 bytes on x86_64/Darwin). If it doesn't, it's
800     // likely that the string isn't initialized and we're reading garbage.
801     ExecutionContext exe_ctx(location_sp->GetExecutionContextRef());
802     const std::optional<uint64_t> max_bytes =
803         location_sp->GetCompilerType().GetByteSize(
804             exe_ctx.GetBestExecutionContextScope());
805     if (!max_bytes || size > *max_bytes || !location_sp)
806       return {};
807 
808     return std::make_pair(size, location_sp);
809   }
810 
811   // we can use the layout_decider object as the data pointer
812   ValueObjectSP location_sp =
813       l->GetChildMemberWithName(ConstString("__data_"), /*can_create=*/true);
814   ValueObjectSP size_vo =
815       l->GetChildMemberWithName(ConstString("__size_"), /*can_create=*/true);
816   ValueObjectSP capacity_vo =
817       l->GetChildMemberWithName(ConstString("__cap_"), /*can_create=*/true);
818   if (!size_vo || !location_sp || !capacity_vo)
819     return {};
820   size = size_vo->GetValueAsUnsigned(LLDB_INVALID_OFFSET);
821   uint64_t capacity = capacity_vo->GetValueAsUnsigned(LLDB_INVALID_OFFSET);
822   if (!using_bitmasks && layout == StringLayout::CSD)
823     capacity *= 2;
824   if (size == LLDB_INVALID_OFFSET || capacity == LLDB_INVALID_OFFSET ||
825       capacity < size)
826     return {};
827   return std::make_pair(size, location_sp);
828 }
829 
830 static bool
831 LibcxxWStringSummaryProvider(ValueObject &valobj, Stream &stream,
832                              const TypeSummaryOptions &summary_options,
833                              ValueObjectSP location_sp, size_t size) {
834   if (size == 0) {
835     stream.Printf("L\"\"");
836     return true;
837   }
838   if (!location_sp)
839     return false;
840 
841   StringPrinter::ReadBufferAndDumpToStreamOptions options(valobj);
842   if (summary_options.GetCapping() == TypeSummaryCapping::eTypeSummaryCapped) {
843     const auto max_size = valobj.GetTargetSP()->GetMaximumSizeOfStringSummary();
844     if (size > max_size) {
845       size = max_size;
846       options.SetIsTruncated(true);
847     }
848   }
849 
850   DataExtractor extractor;
851   const size_t bytes_read = location_sp->GetPointeeData(extractor, 0, size);
852   if (bytes_read < size)
853     return false;
854 
855   // std::wstring::size() is measured in 'characters', not bytes
856   TypeSystemClangSP scratch_ts_sp =
857       ScratchTypeSystemClang::GetForTarget(*valobj.GetTargetSP());
858   if (!scratch_ts_sp)
859     return false;
860 
861   auto wchar_t_size =
862       scratch_ts_sp->GetBasicType(lldb::eBasicTypeWChar).GetByteSize(nullptr);
863   if (!wchar_t_size)
864     return false;
865 
866   options.SetData(std::move(extractor));
867   options.SetStream(&stream);
868   options.SetPrefixToken("L");
869   options.SetQuote('"');
870   options.SetSourceSize(size);
871   options.SetBinaryZeroIsTerminator(false);
872 
873   switch (*wchar_t_size) {
874   case 1:
875     return StringPrinter::ReadBufferAndDumpToStream<
876         lldb_private::formatters::StringPrinter::StringElementType::UTF8>(
877         options);
878     break;
879 
880   case 2:
881     return StringPrinter::ReadBufferAndDumpToStream<
882         lldb_private::formatters::StringPrinter::StringElementType::UTF16>(
883         options);
884     break;
885 
886   case 4:
887     return StringPrinter::ReadBufferAndDumpToStream<
888         lldb_private::formatters::StringPrinter::StringElementType::UTF32>(
889         options);
890   }
891   return false;
892 }
893 
894 bool lldb_private::formatters::LibcxxWStringSummaryProvider(
895     ValueObject &valobj, Stream &stream,
896     const TypeSummaryOptions &summary_options) {
897   auto string_info = ExtractLibcxxStringInfo(valobj);
898   if (!string_info)
899     return false;
900   uint64_t size;
901   ValueObjectSP location_sp;
902   std::tie(size, location_sp) = *string_info;
903 
904   return ::LibcxxWStringSummaryProvider(valobj, stream, summary_options,
905                                         location_sp, size);
906 }
907 
908 template <StringPrinter::StringElementType element_type>
909 static bool
910 LibcxxStringSummaryProvider(ValueObject &valobj, Stream &stream,
911                             const TypeSummaryOptions &summary_options,
912                             std::string prefix_token, ValueObjectSP location_sp,
913                             uint64_t size) {
914 
915   if (size == 0) {
916     stream.Printf("\"\"");
917     return true;
918   }
919 
920   if (!location_sp)
921     return false;
922 
923   StringPrinter::ReadBufferAndDumpToStreamOptions options(valobj);
924 
925   if (summary_options.GetCapping() == TypeSummaryCapping::eTypeSummaryCapped) {
926     const auto max_size = valobj.GetTargetSP()->GetMaximumSizeOfStringSummary();
927     if (size > max_size) {
928       size = max_size;
929       options.SetIsTruncated(true);
930     }
931   }
932 
933   {
934     DataExtractor extractor;
935     const size_t bytes_read = location_sp->GetPointeeData(extractor, 0, size);
936     if (bytes_read < size)
937       return false;
938 
939     options.SetData(std::move(extractor));
940   }
941   options.SetStream(&stream);
942   if (prefix_token.empty())
943     options.SetPrefixToken(nullptr);
944   else
945     options.SetPrefixToken(prefix_token);
946   options.SetQuote('"');
947   options.SetSourceSize(size);
948   options.SetBinaryZeroIsTerminator(false);
949   return StringPrinter::ReadBufferAndDumpToStream<element_type>(options);
950 }
951 
952 template <StringPrinter::StringElementType element_type>
953 static bool
954 LibcxxStringSummaryProvider(ValueObject &valobj, Stream &stream,
955                             const TypeSummaryOptions &summary_options,
956                             std::string prefix_token) {
957   auto string_info = ExtractLibcxxStringInfo(valobj);
958   if (!string_info)
959     return false;
960   uint64_t size;
961   ValueObjectSP location_sp;
962   std::tie(size, location_sp) = *string_info;
963 
964   return LibcxxStringSummaryProvider<element_type>(
965       valobj, stream, summary_options, prefix_token, location_sp, size);
966 }
967 template <StringPrinter::StringElementType element_type>
968 static bool formatStringImpl(ValueObject &valobj, Stream &stream,
969                              const TypeSummaryOptions &summary_options,
970                              std::string prefix_token) {
971   StreamString scratch_stream;
972   const bool success = LibcxxStringSummaryProvider<element_type>(
973       valobj, scratch_stream, summary_options, prefix_token);
974   if (success)
975     stream << scratch_stream.GetData();
976   else
977     stream << "Summary Unavailable";
978   return true;
979 }
980 
981 bool lldb_private::formatters::LibcxxStringSummaryProviderASCII(
982     ValueObject &valobj, Stream &stream,
983     const TypeSummaryOptions &summary_options) {
984   return formatStringImpl<StringPrinter::StringElementType::ASCII>(
985       valobj, stream, summary_options, "");
986 }
987 
988 bool lldb_private::formatters::LibcxxStringSummaryProviderUTF16(
989     ValueObject &valobj, Stream &stream,
990     const TypeSummaryOptions &summary_options) {
991   return formatStringImpl<StringPrinter::StringElementType::UTF16>(
992       valobj, stream, summary_options, "u");
993 }
994 
995 bool lldb_private::formatters::LibcxxStringSummaryProviderUTF32(
996     ValueObject &valobj, Stream &stream,
997     const TypeSummaryOptions &summary_options) {
998   return formatStringImpl<StringPrinter::StringElementType::UTF32>(
999       valobj, stream, summary_options, "U");
1000 }
1001 
1002 static std::tuple<bool, ValueObjectSP, size_t>
1003 LibcxxExtractStringViewData(ValueObject& valobj) {
1004   auto dataobj = GetChildMemberWithName(
1005       valobj, {ConstString("__data_"), ConstString("__data")});
1006   auto sizeobj = GetChildMemberWithName(
1007       valobj, {ConstString("__size_"), ConstString("__size")});
1008   if (!dataobj || !sizeobj)
1009     return std::make_tuple<bool,ValueObjectSP,size_t>(false, {}, {});
1010 
1011   if (!dataobj->GetError().Success() || !sizeobj->GetError().Success())
1012     return std::make_tuple<bool,ValueObjectSP,size_t>(false, {}, {});
1013 
1014   bool success{false};
1015   uint64_t size = sizeobj->GetValueAsUnsigned(0, &success);
1016   if (!success)
1017     return std::make_tuple<bool,ValueObjectSP,size_t>(false, {}, {});
1018 
1019   return std::make_tuple(true,dataobj,size);
1020 }
1021 
1022 template <StringPrinter::StringElementType element_type>
1023 static bool formatStringViewImpl(ValueObject &valobj, Stream &stream,
1024                                  const TypeSummaryOptions &summary_options,
1025                                  std::string prefix_token) {
1026 
1027   bool success;
1028   ValueObjectSP dataobj;
1029   size_t size;
1030   std::tie(success, dataobj, size) = LibcxxExtractStringViewData(valobj);
1031 
1032   if (!success) {
1033     stream << "Summary Unavailable";
1034     return true;
1035   }
1036 
1037   return LibcxxStringSummaryProvider<element_type>(
1038       valobj, stream, summary_options, prefix_token, dataobj, size);
1039 }
1040 
1041 bool lldb_private::formatters::LibcxxStringViewSummaryProviderASCII(
1042     ValueObject &valobj, Stream &stream,
1043     const TypeSummaryOptions &summary_options) {
1044   return formatStringViewImpl<StringPrinter::StringElementType::ASCII>(
1045       valobj, stream, summary_options, "");
1046 }
1047 
1048 bool lldb_private::formatters::LibcxxStringViewSummaryProviderUTF16(
1049     ValueObject &valobj, Stream &stream,
1050     const TypeSummaryOptions &summary_options) {
1051   return formatStringViewImpl<StringPrinter::StringElementType::UTF16>(
1052       valobj, stream, summary_options, "u");
1053 }
1054 
1055 bool lldb_private::formatters::LibcxxStringViewSummaryProviderUTF32(
1056     ValueObject &valobj, Stream &stream,
1057     const TypeSummaryOptions &summary_options) {
1058   return formatStringViewImpl<StringPrinter::StringElementType::UTF32>(
1059       valobj, stream, summary_options, "U");
1060 }
1061 
1062 bool lldb_private::formatters::LibcxxWStringViewSummaryProvider(
1063     ValueObject &valobj, Stream &stream,
1064     const TypeSummaryOptions &summary_options) {
1065 
1066   bool success;
1067   ValueObjectSP dataobj;
1068   size_t size;
1069   std::tie( success, dataobj, size ) = LibcxxExtractStringViewData(valobj);
1070 
1071   if (!success) {
1072     stream << "Summary Unavailable";
1073     return true;
1074   }
1075 
1076 
1077   return ::LibcxxWStringSummaryProvider(valobj, stream, summary_options,
1078                                         dataobj, size);
1079 }
1080