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LibCxxMap.cpp
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1 //===-- LibCxxMap.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 
12 #include "lldb/Core/ValueObject.h"
15 #include "lldb/Target/Target.h"
17 #include "lldb/Utility/Endian.h"
18 #include "lldb/Utility/Status.h"
19 #include "lldb/Utility/Stream.h"
20 
21 using namespace lldb;
22 using namespace lldb_private;
23 using namespace lldb_private::formatters;
24 
25 class MapEntry {
26 public:
27  MapEntry() = default;
28  explicit MapEntry(ValueObjectSP entry_sp) : m_entry_sp(entry_sp) {}
29  explicit MapEntry(ValueObject *entry)
30  : m_entry_sp(entry ? entry->GetSP() : ValueObjectSP()) {}
31 
32  ValueObjectSP left() const {
33  static ConstString g_left("__left_");
34  if (!m_entry_sp)
35  return m_entry_sp;
36  return m_entry_sp->GetSyntheticChildAtOffset(
37  0, m_entry_sp->GetCompilerType(), true);
38  }
39 
40  ValueObjectSP right() const {
41  static ConstString g_right("__right_");
42  if (!m_entry_sp)
43  return m_entry_sp;
44  return m_entry_sp->GetSyntheticChildAtOffset(
45  m_entry_sp->GetProcessSP()->GetAddressByteSize(),
46  m_entry_sp->GetCompilerType(), true);
47  }
48 
49  ValueObjectSP parent() const {
50  static ConstString g_parent("__parent_");
51  if (!m_entry_sp)
52  return m_entry_sp;
53  return m_entry_sp->GetSyntheticChildAtOffset(
54  2 * m_entry_sp->GetProcessSP()->GetAddressByteSize(),
55  m_entry_sp->GetCompilerType(), true);
56  }
57 
58  uint64_t value() const {
59  if (!m_entry_sp)
60  return 0;
61  return m_entry_sp->GetValueAsUnsigned(0);
62  }
63 
64  bool error() const {
65  if (!m_entry_sp)
66  return true;
67  return m_entry_sp->GetError().Fail();
68  }
69 
70  bool null() const { return (value() == 0); }
71 
72  ValueObjectSP GetEntry() const { return m_entry_sp; }
73 
74  void SetEntry(ValueObjectSP entry) { m_entry_sp = entry; }
75 
76  bool operator==(const MapEntry &rhs) const {
77  return (rhs.m_entry_sp.get() == m_entry_sp.get());
78  }
79 
80 private:
81  ValueObjectSP m_entry_sp;
82 };
83 
84 class MapIterator {
85 public:
86  MapIterator() = default;
87  MapIterator(MapEntry entry, size_t depth = 0)
88  : m_entry(std::move(entry)), m_max_depth(depth), m_error(false) {}
89  MapIterator(ValueObjectSP entry, size_t depth = 0)
90  : m_entry(std::move(entry)), m_max_depth(depth), m_error(false) {}
92  : m_entry(rhs.m_entry), m_max_depth(rhs.m_max_depth), m_error(false) {}
93  MapIterator(ValueObject *entry, size_t depth = 0)
94  : m_entry(entry), m_max_depth(depth), m_error(false) {}
95 
96  MapIterator &operator=(const MapIterator &) = default;
97 
98  ValueObjectSP value() { return m_entry.GetEntry(); }
99 
100  ValueObjectSP advance(size_t count) {
101  ValueObjectSP fail;
102  if (m_error)
103  return fail;
104  size_t steps = 0;
105  while (count > 0) {
106  next();
107  count--, steps++;
108  if (m_error || m_entry.null() || (steps > m_max_depth))
109  return fail;
110  }
111  return m_entry.GetEntry();
112  }
113 
114 protected:
115  void next() {
116  if (m_entry.null())
117  return;
118  MapEntry right(m_entry.right());
119  if (!right.null()) {
120  m_entry = tree_min(std::move(right));
121  return;
122  }
123  size_t steps = 0;
124  while (!is_left_child(m_entry)) {
125  if (m_entry.error()) {
126  m_error = true;
127  return;
128  }
129  m_entry.SetEntry(m_entry.parent());
130  steps++;
131  if (steps > m_max_depth) {
132  m_entry = MapEntry();
133  return;
134  }
135  }
136  m_entry = MapEntry(m_entry.parent());
137  }
138 
139 private:
141  if (x.null())
142  return MapEntry();
143  MapEntry left(x.left());
144  size_t steps = 0;
145  while (!left.null()) {
146  if (left.error()) {
147  m_error = true;
148  return MapEntry();
149  }
150  x = left;
151  left.SetEntry(x.left());
152  steps++;
153  if (steps > m_max_depth)
154  return MapEntry();
155  }
156  return x;
157  }
158 
159  bool is_left_child(const MapEntry &x) {
160  if (x.null())
161  return false;
162  MapEntry rhs(x.parent());
163  rhs.SetEntry(rhs.left());
164  return x.value() == rhs.value();
165  }
166 
168  size_t m_max_depth;
169  bool m_error;
170 };
171 
172 namespace lldb_private {
173 namespace formatters {
175 public:
176  LibcxxStdMapSyntheticFrontEnd(lldb::ValueObjectSP valobj_sp);
177 
178  ~LibcxxStdMapSyntheticFrontEnd() override = default;
179 
180  size_t CalculateNumChildren() override;
181 
182  lldb::ValueObjectSP GetChildAtIndex(size_t idx) override;
183 
184  bool Update() override;
185 
186  bool MightHaveChildren() override;
187 
188  size_t GetIndexOfChildWithName(ConstString name) override;
189 
190 private:
191  bool GetDataType();
192 
193  void GetValueOffset(const lldb::ValueObjectSP &node);
194 
199  size_t m_count;
200  std::map<size_t, MapIterator> m_iterators;
201 };
202 } // namespace formatters
203 } // namespace lldb_private
204 
206  LibcxxStdMapSyntheticFrontEnd(lldb::ValueObjectSP valobj_sp)
207  : SyntheticChildrenFrontEnd(*valobj_sp), m_tree(nullptr),
208  m_root_node(nullptr), m_element_type(), m_skip_size(UINT32_MAX),
209  m_count(UINT32_MAX), m_iterators() {
210  if (valobj_sp)
211  Update();
212 }
213 
216  static ConstString g___pair3_("__pair3_");
217  static ConstString g___first_("__first_");
218  static ConstString g___value_("__value_");
219 
220  if (m_count != UINT32_MAX)
221  return m_count;
222  if (m_tree == nullptr)
223  return 0;
224  ValueObjectSP m_item(m_tree->GetChildMemberWithName(g___pair3_, true));
225  if (!m_item)
226  return 0;
227 
228  switch (m_item->GetCompilerType().GetNumDirectBaseClasses()) {
229  case 1:
230  // Assume a pre llvm r300140 __compressed_pair implementation:
231  m_item = m_item->GetChildMemberWithName(g___first_, true);
232  break;
233  case 2: {
234  // Assume a post llvm r300140 __compressed_pair implementation:
235  ValueObjectSP first_elem_parent = m_item->GetChildAtIndex(0, true);
236  m_item = first_elem_parent->GetChildMemberWithName(g___value_, true);
237  break;
238  }
239  default:
240  return false;
241  }
242 
243  if (!m_item)
244  return 0;
245  m_count = m_item->GetValueAsUnsigned(0);
246  return m_count;
247 }
248 
250  static ConstString g___value_("__value_");
251  static ConstString g_tree_("__tree_");
252  static ConstString g_pair3("__pair3_");
253 
254  if (m_element_type.GetOpaqueQualType() && m_element_type.GetTypeSystem())
255  return true;
256  m_element_type.Clear();
257  ValueObjectSP deref;
258  Status error;
259  deref = m_root_node->Dereference(error);
260  if (!deref || error.Fail())
261  return false;
262  deref = deref->GetChildMemberWithName(g___value_, true);
263  if (deref) {
264  m_element_type = deref->GetCompilerType();
265  return true;
266  }
267  deref = m_backend.GetChildAtNamePath({g_tree_, g_pair3});
268  if (!deref)
269  return false;
270  m_element_type = deref->GetCompilerType()
271  .GetTypeTemplateArgument(1)
272  .GetTypeTemplateArgument(1);
273  if (m_element_type) {
274  std::string name;
275  uint64_t bit_offset_ptr;
276  uint32_t bitfield_bit_size_ptr;
277  bool is_bitfield_ptr;
278  m_element_type = m_element_type.GetFieldAtIndex(
279  0, name, &bit_offset_ptr, &bitfield_bit_size_ptr, &is_bitfield_ptr);
280  m_element_type = m_element_type.GetTypedefedType();
281  return m_element_type.IsValid();
282  } else {
283  m_element_type = m_backend.GetCompilerType().GetTypeTemplateArgument(0);
284  return m_element_type.IsValid();
285  }
286 }
287 
289  const lldb::ValueObjectSP &node) {
290  if (m_skip_size != UINT32_MAX)
291  return;
292  if (!node)
293  return;
294  CompilerType node_type(node->GetCompilerType());
295  uint64_t bit_offset;
296  if (node_type.GetIndexOfFieldWithName("__value_", nullptr, &bit_offset) !=
297  UINT32_MAX) {
298  m_skip_size = bit_offset / 8u;
299  } else {
300  TypeSystemClang *ast_ctx =
301  llvm::dyn_cast_or_null<TypeSystemClang>(node_type.GetTypeSystem());
302  if (!ast_ctx)
303  return;
304  CompilerType tree_node_type = ast_ctx->CreateStructForIdentifier(
305  ConstString(),
306  {{"ptr0", ast_ctx->GetBasicType(lldb::eBasicTypeVoid).GetPointerType()},
307  {"ptr1", ast_ctx->GetBasicType(lldb::eBasicTypeVoid).GetPointerType()},
308  {"ptr2", ast_ctx->GetBasicType(lldb::eBasicTypeVoid).GetPointerType()},
309  {"cw", ast_ctx->GetBasicType(lldb::eBasicTypeBool)},
310  {"payload", (m_element_type.GetCompleteType(), m_element_type)}});
311  std::string child_name;
312  uint32_t child_byte_size;
313  int32_t child_byte_offset = 0;
314  uint32_t child_bitfield_bit_size;
315  uint32_t child_bitfield_bit_offset;
316  bool child_is_base_class;
317  bool child_is_deref_of_parent;
318  uint64_t language_flags;
319  if (tree_node_type
320  .GetChildCompilerTypeAtIndex(
321  nullptr, 4, true, true, true, child_name, child_byte_size,
322  child_byte_offset, child_bitfield_bit_size,
323  child_bitfield_bit_offset, child_is_base_class,
324  child_is_deref_of_parent, nullptr, language_flags)
325  .IsValid())
326  m_skip_size = (uint32_t)child_byte_offset;
327  }
328 }
329 
330 lldb::ValueObjectSP
332  size_t idx) {
333  static ConstString g___cc("__cc");
334  static ConstString g___nc("__nc");
335  static ConstString g___value_("__value_");
336 
337  if (idx >= CalculateNumChildren())
338  return lldb::ValueObjectSP();
339  if (m_tree == nullptr || m_root_node == nullptr)
340  return lldb::ValueObjectSP();
341 
342  MapIterator iterator(m_root_node, CalculateNumChildren());
343 
344  const bool need_to_skip = (idx > 0);
345  size_t actual_advancde = idx;
346  if (need_to_skip) {
347  auto cached_iterator = m_iterators.find(idx - 1);
348  if (cached_iterator != m_iterators.end()) {
349  iterator = cached_iterator->second;
350  actual_advancde = 1;
351  }
352  }
353 
354  ValueObjectSP iterated_sp(iterator.advance(actual_advancde));
355  if (!iterated_sp) {
356  // this tree is garbage - stop
357  m_tree =
358  nullptr; // this will stop all future searches until an Update() happens
359  return iterated_sp;
360  }
361  if (GetDataType()) {
362  if (!need_to_skip) {
363  Status error;
364  iterated_sp = iterated_sp->Dereference(error);
365  if (!iterated_sp || error.Fail()) {
366  m_tree = nullptr;
367  return lldb::ValueObjectSP();
368  }
369  GetValueOffset(iterated_sp);
370  auto child_sp = iterated_sp->GetChildMemberWithName(g___value_, true);
371  if (child_sp)
372  iterated_sp = child_sp;
373  else
374  iterated_sp = iterated_sp->GetSyntheticChildAtOffset(
375  m_skip_size, m_element_type, true);
376  if (!iterated_sp) {
377  m_tree = nullptr;
378  return lldb::ValueObjectSP();
379  }
380  } else {
381  // because of the way our debug info is made, we need to read item 0
382  // first so that we can cache information used to generate other elements
383  if (m_skip_size == UINT32_MAX)
384  GetChildAtIndex(0);
385  if (m_skip_size == UINT32_MAX) {
386  m_tree = nullptr;
387  return lldb::ValueObjectSP();
388  }
389  iterated_sp = iterated_sp->GetSyntheticChildAtOffset(
390  m_skip_size, m_element_type, true);
391  if (!iterated_sp) {
392  m_tree = nullptr;
393  return lldb::ValueObjectSP();
394  }
395  }
396  } else {
397  m_tree = nullptr;
398  return lldb::ValueObjectSP();
399  }
400  // at this point we have a valid
401  // we need to copy current_sp into a new object otherwise we will end up with
402  // all items named __value_
403  DataExtractor data;
404  Status error;
405  iterated_sp->GetData(data, error);
406  if (error.Fail()) {
407  m_tree = nullptr;
408  return lldb::ValueObjectSP();
409  }
410  StreamString name;
411  name.Printf("[%" PRIu64 "]", (uint64_t)idx);
412  auto potential_child_sp = CreateValueObjectFromData(
413  name.GetString(), data, m_backend.GetExecutionContextRef(),
414  m_element_type);
415  if (potential_child_sp) {
416  switch (potential_child_sp->GetNumChildren()) {
417  case 1: {
418  auto child0_sp = potential_child_sp->GetChildAtIndex(0, true);
419  if (child0_sp && child0_sp->GetName() == g___cc)
420  potential_child_sp = child0_sp->Clone(ConstString(name.GetString()));
421  break;
422  }
423  case 2: {
424  auto child0_sp = potential_child_sp->GetChildAtIndex(0, true);
425  auto child1_sp = potential_child_sp->GetChildAtIndex(1, true);
426  if (child0_sp && child0_sp->GetName() == g___cc && child1_sp &&
427  child1_sp->GetName() == g___nc)
428  potential_child_sp = child0_sp->Clone(ConstString(name.GetString()));
429  break;
430  }
431  }
432  }
433  m_iterators[idx] = iterator;
434  return potential_child_sp;
435 }
436 
438  static ConstString g___tree_("__tree_");
439  static ConstString g___begin_node_("__begin_node_");
440  m_count = UINT32_MAX;
441  m_tree = m_root_node = nullptr;
442  m_iterators.clear();
443  m_tree = m_backend.GetChildMemberWithName(g___tree_, true).get();
444  if (!m_tree)
445  return false;
446  m_root_node = m_tree->GetChildMemberWithName(g___begin_node_, true).get();
447  return false;
448 }
449 
452  return true;
453 }
454 
457  return ExtractIndexFromString(name.GetCString());
458 }
459 
462  CXXSyntheticChildren *, lldb::ValueObjectSP valobj_sp) {
463  return (valobj_sp ? new LibcxxStdMapSyntheticFrontEnd(valobj_sp) : nullptr);
464 }
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Definition: LibCxxMap.cpp:32
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