1//===-- ValueObjectSyntheticFilter.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 "lldb/ValueObject/ValueObjectSyntheticFilter.h"
10
11#include "lldb/Core/Value.h"
12#include "lldb/DataFormatters/TypeSynthetic.h"
13#include "lldb/Target/ExecutionContext.h"
14#include "lldb/Utility/ConstString.h"
15#include "lldb/Utility/LLDBLog.h"
16#include "lldb/Utility/Log.h"
17#include "lldb/Utility/Status.h"
18#include "lldb/ValueObject/ValueObject.h"
19
20#include "llvm/ADT/STLExtras.h"
21#include <optional>
22
23namespace lldb_private {
24class Declaration;
25}
26
27using namespace lldb_private;
28
29class DummySyntheticFrontEnd : public SyntheticChildrenFrontEnd {
30public:
31 DummySyntheticFrontEnd(ValueObject &backend)
32 : SyntheticChildrenFrontEnd(backend) {}
33
34 llvm::Expected<uint32_t> CalculateNumChildren() override {
35 return m_backend.GetNumChildren();
36 }
37
38 lldb::ValueObjectSP GetChildAtIndex(uint32_t idx) override {
39 return m_backend.GetChildAtIndex(idx);
40 }
41
42 llvm::Expected<size_t> GetIndexOfChildWithName(ConstString name) override {
43 return m_backend.GetIndexOfChildWithName(name);
44 }
45
46 bool MightHaveChildren() override { return m_backend.MightHaveChildren(); }
47
48 lldb::ChildCacheState Update() override {
49 return lldb::ChildCacheState::eRefetch;
50 }
51};
52
53ValueObjectSynthetic::ValueObjectSynthetic(ValueObject &parent,
54 lldb::SyntheticChildrenSP filter)
55 : ValueObject(parent), m_synth_sp(std::move(filter)), m_children_byindex(),
56 m_name_toindex(), m_synthetic_children_cache(),
57 m_synthetic_children_count(UINT32_MAX),
58 m_parent_type_name(parent.GetTypeName()),
59 m_might_have_children(eLazyBoolCalculate),
60 m_provides_value(eLazyBoolCalculate) {
61 SetName(parent.GetName());
62 // Copying the data of an incomplete type won't work as it has no byte size.
63 if (m_parent->GetCompilerType().IsCompleteType())
64 CopyValueData(source: m_parent);
65 CreateSynthFilter();
66}
67
68ValueObjectSynthetic::~ValueObjectSynthetic() = default;
69
70CompilerType ValueObjectSynthetic::GetCompilerTypeImpl() {
71 return m_parent->GetCompilerType();
72}
73
74ConstString ValueObjectSynthetic::GetTypeName() {
75 return m_parent->GetTypeName();
76}
77
78ConstString ValueObjectSynthetic::GetQualifiedTypeName() {
79 return m_parent->GetQualifiedTypeName();
80}
81
82ConstString ValueObjectSynthetic::GetDisplayTypeName() {
83 if (ConstString synth_name = m_synth_filter_up->GetSyntheticTypeName())
84 return synth_name;
85
86 return m_parent->GetDisplayTypeName();
87}
88
89llvm::Expected<uint32_t>
90ValueObjectSynthetic::CalculateNumChildren(uint32_t max) {
91 Log *log = GetLog(mask: LLDBLog::DataFormatters);
92
93 UpdateValueIfNeeded();
94 if (m_synthetic_children_count < UINT32_MAX)
95 return m_synthetic_children_count <= max ? m_synthetic_children_count : max;
96
97 if (max < UINT32_MAX) {
98 auto num_children = m_synth_filter_up->CalculateNumChildren(max);
99 LLDB_LOGF(log,
100 "[ValueObjectSynthetic::CalculateNumChildren] for VO of name "
101 "%s and type %s, the filter returned %u child values",
102 GetName().AsCString(), GetTypeName().AsCString(),
103 num_children ? *num_children : 0);
104 return num_children;
105 } else {
106 auto num_children_or_err = m_synth_filter_up->CalculateNumChildren(max);
107 if (!num_children_or_err) {
108 m_synthetic_children_count = 0;
109 return num_children_or_err;
110 }
111 auto num_children = (m_synthetic_children_count = *num_children_or_err);
112 LLDB_LOGF(log,
113 "[ValueObjectSynthetic::CalculateNumChildren] for VO of name "
114 "%s and type %s, the filter returned %u child values",
115 GetName().AsCString(), GetTypeName().AsCString(), num_children);
116 return num_children;
117 }
118}
119
120lldb::ValueObjectSP
121ValueObjectSynthetic::GetDynamicValue(lldb::DynamicValueType valueType) {
122 if (!m_parent)
123 return lldb::ValueObjectSP();
124 if (IsDynamic() && GetDynamicValueType() == valueType)
125 return GetSP();
126 return m_parent->GetDynamicValue(valueType);
127}
128
129bool ValueObjectSynthetic::MightHaveChildren() {
130 if (m_might_have_children == eLazyBoolCalculate)
131 m_might_have_children =
132 (m_synth_filter_up->MightHaveChildren() ? eLazyBoolYes : eLazyBoolNo);
133 return (m_might_have_children != eLazyBoolNo);
134}
135
136llvm::Expected<uint64_t> ValueObjectSynthetic::GetByteSize() {
137 return m_parent->GetByteSize();
138}
139
140lldb::ValueType ValueObjectSynthetic::GetValueType() const {
141 return m_parent->GetValueType();
142}
143
144void ValueObjectSynthetic::CreateSynthFilter() {
145 ValueObject *valobj_for_frontend = m_parent;
146 if (m_synth_sp->WantsDereference()) {
147 CompilerType type = m_parent->GetCompilerType();
148 if (type.IsValid() && type.IsPointerOrReferenceType()) {
149 Status error;
150 lldb::ValueObjectSP deref_sp = m_parent->Dereference(error);
151 if (error.Success())
152 valobj_for_frontend = deref_sp.get();
153 }
154 }
155 m_synth_filter_up = (m_synth_sp->GetFrontEnd(backend&: *valobj_for_frontend));
156 if (!m_synth_filter_up)
157 m_synth_filter_up = std::make_unique<DummySyntheticFrontEnd>(args&: *m_parent);
158}
159
160bool ValueObjectSynthetic::UpdateValue() {
161 Log *log = GetLog(mask: LLDBLog::DataFormatters);
162
163 SetValueIsValid(false);
164 m_error.Clear();
165
166 if (!m_parent->UpdateValueIfNeeded(update_format: false)) {
167 // our parent could not update.. as we are meaningless without a parent,
168 // just stop
169 if (m_parent->GetError().Fail())
170 m_error = m_parent->GetError().Clone();
171 return false;
172 }
173
174 // Regenerate the synthetic filter if our typename changes. When the (dynamic)
175 // type of an object changes, so does their synthetic filter of choice.
176 ConstString new_parent_type_name = m_parent->GetTypeName();
177 if (new_parent_type_name != m_parent_type_name) {
178 LLDB_LOGF(log,
179 "[ValueObjectSynthetic::UpdateValue] name=%s, type changed "
180 "from %s to %s, recomputing synthetic filter",
181 GetName().AsCString(), m_parent_type_name.AsCString(),
182 new_parent_type_name.AsCString());
183 m_parent_type_name = new_parent_type_name;
184 CreateSynthFilter();
185 }
186
187 // let our backend do its update
188 if (m_synth_filter_up->Update() == lldb::ChildCacheState::eRefetch) {
189 LLDB_LOGF(log,
190 "[ValueObjectSynthetic::UpdateValue] name=%s, synthetic "
191 "filter said caches are stale - clearing",
192 GetName().AsCString());
193 // filter said that cached values are stale
194 {
195 std::lock_guard<std::mutex> guard(m_child_mutex);
196 m_children_byindex.clear();
197 m_name_toindex.clear();
198 }
199 // usually, an object's value can change but this does not alter its
200 // children count for a synthetic VO that might indeed happen, so we need
201 // to tell the upper echelons that they need to come back to us asking for
202 // children
203 m_flags.m_children_count_valid = false;
204 {
205 std::lock_guard<std::mutex> guard(m_child_mutex);
206 m_synthetic_children_cache.clear();
207 }
208 m_synthetic_children_count = UINT32_MAX;
209 m_might_have_children = eLazyBoolCalculate;
210 } else {
211 LLDB_LOGF(log,
212 "[ValueObjectSynthetic::UpdateValue] name=%s, synthetic "
213 "filter said caches are still valid",
214 GetName().AsCString());
215 }
216
217 m_provides_value = eLazyBoolCalculate;
218
219 lldb::ValueObjectSP synth_val(m_synth_filter_up->GetSyntheticValue());
220
221 if (synth_val && synth_val->CanProvideValue()) {
222 LLDB_LOGF(log,
223 "[ValueObjectSynthetic::UpdateValue] name=%s, synthetic "
224 "filter said it can provide a value",
225 GetName().AsCString());
226
227 m_provides_value = eLazyBoolYes;
228 CopyValueData(source: synth_val.get());
229 } else {
230 LLDB_LOGF(log,
231 "[ValueObjectSynthetic::UpdateValue] name=%s, synthetic "
232 "filter said it will not provide a value",
233 GetName().AsCString());
234
235 m_provides_value = eLazyBoolNo;
236 // Copying the data of an incomplete type won't work as it has no byte size.
237 if (m_parent->GetCompilerType().IsCompleteType())
238 CopyValueData(source: m_parent);
239 }
240
241 SetValueIsValid(true);
242 return true;
243}
244
245lldb::ValueObjectSP ValueObjectSynthetic::GetChildAtIndex(uint32_t idx,
246 bool can_create) {
247 Log *log = GetLog(mask: LLDBLog::DataFormatters);
248
249 LLDB_LOGF(log,
250 "[ValueObjectSynthetic::GetChildAtIndex] name=%s, retrieving "
251 "child at index %u",
252 GetName().AsCString(), idx);
253
254 UpdateValueIfNeeded();
255
256 ValueObject *valobj;
257 bool child_is_cached;
258 {
259 std::lock_guard<std::mutex> guard(m_child_mutex);
260 auto cached_child_it = m_children_byindex.find(x: idx);
261 child_is_cached = cached_child_it != m_children_byindex.end();
262 if (child_is_cached)
263 valobj = cached_child_it->second;
264 }
265
266 if (!child_is_cached) {
267 if (can_create && m_synth_filter_up != nullptr) {
268 LLDB_LOGF(log,
269 "[ValueObjectSynthetic::GetChildAtIndex] name=%s, child at "
270 "index %u not cached and will be created",
271 GetName().AsCString(), idx);
272
273 lldb::ValueObjectSP synth_guy = m_synth_filter_up->GetChildAtIndex(idx);
274
275 LLDB_LOGF(
276 log,
277 "[ValueObjectSynthetic::GetChildAtIndex] name=%s, child at index "
278 "%u created as %p (is "
279 "synthetic: %s)",
280 GetName().AsCString(), idx, static_cast<void *>(synth_guy.get()),
281 synth_guy.get()
282 ? (synth_guy->IsSyntheticChildrenGenerated() ? "yes" : "no")
283 : "no");
284
285 if (!synth_guy)
286 return synth_guy;
287
288 {
289 std::lock_guard<std::mutex> guard(m_child_mutex);
290 if (synth_guy->IsSyntheticChildrenGenerated())
291 m_synthetic_children_cache.push_back(x: synth_guy);
292 m_children_byindex[idx] = synth_guy.get();
293 }
294 synth_guy->SetPreferredDisplayLanguageIfNeeded(
295 GetPreferredDisplayLanguage());
296 return synth_guy;
297 } else {
298 LLDB_LOGF(log,
299 "[ValueObjectSynthetic::GetChildAtIndex] name=%s, child at "
300 "index %u not cached and cannot "
301 "be created (can_create = %s, synth_filter = %p)",
302 GetName().AsCString(), idx, can_create ? "yes" : "no",
303 static_cast<void *>(m_synth_filter_up.get()));
304
305 return lldb::ValueObjectSP();
306 }
307 } else {
308 LLDB_LOGF(log,
309 "[ValueObjectSynthetic::GetChildAtIndex] name=%s, child at "
310 "index %u cached as %p",
311 GetName().AsCString(), idx, static_cast<void *>(valobj));
312
313 return valobj->GetSP();
314 }
315}
316
317lldb::ValueObjectSP
318ValueObjectSynthetic::GetChildMemberWithName(llvm::StringRef name,
319 bool can_create) {
320 UpdateValueIfNeeded();
321
322 auto index_or_err = GetIndexOfChildWithName(name);
323
324 if (!index_or_err) {
325 llvm::consumeError(Err: index_or_err.takeError());
326 return lldb::ValueObjectSP();
327 }
328
329 return GetChildAtIndex(idx: *index_or_err, can_create);
330}
331
332llvm::Expected<size_t>
333ValueObjectSynthetic::GetIndexOfChildWithName(llvm::StringRef name_ref) {
334 UpdateValueIfNeeded();
335
336 ConstString name(name_ref);
337
338 std::optional<uint32_t> found_index = std::nullopt;
339 {
340 std::lock_guard<std::mutex> guard(m_child_mutex);
341 auto name_to_index = m_name_toindex.find(x: name.GetCString());
342 if (name_to_index != m_name_toindex.end())
343 found_index = name_to_index->second;
344 }
345
346 if (!found_index && m_synth_filter_up != nullptr) {
347 auto index_or_err = m_synth_filter_up->GetIndexOfChildWithName(name);
348 if (!index_or_err)
349 return index_or_err.takeError();
350 std::lock_guard<std::mutex> guard(m_child_mutex);
351 m_name_toindex[name.GetCString()] = *index_or_err;
352 return *index_or_err;
353 } else if (!found_index && m_synth_filter_up == nullptr) {
354 return llvm::createStringError(Fmt: "Type has no child named '%s'",
355 Vals: name.AsCString());
356 } else if (found_index)
357 return *found_index;
358
359 return llvm::createStringError(Fmt: "Type has no child named '%s'",
360 Vals: name.AsCString());
361}
362
363bool ValueObjectSynthetic::IsInScope() { return m_parent->IsInScope(); }
364
365lldb::ValueObjectSP ValueObjectSynthetic::GetNonSyntheticValue() {
366 return m_parent->GetSP();
367}
368
369void ValueObjectSynthetic::CopyValueData(ValueObject *source) {
370 if (!source->UpdateValueIfNeeded())
371 return;
372 m_value = source->GetValue();
373 ExecutionContext exe_ctx(GetExecutionContextRef());
374 m_error = m_value.GetValueAsData(exe_ctx: &exe_ctx, data&: m_data, module: GetModule().get());
375}
376
377bool ValueObjectSynthetic::CanProvideValue() {
378 if (!UpdateValueIfNeeded())
379 return false;
380 if (m_provides_value == eLazyBoolYes)
381 return true;
382 return m_parent->CanProvideValue();
383}
384
385bool ValueObjectSynthetic::SetValueFromCString(const char *value_str,
386 Status &error) {
387 return m_parent->SetValueFromCString(value_str, error);
388}
389
390void ValueObjectSynthetic::SetFormat(lldb::Format format) {
391 if (m_parent) {
392 m_parent->ClearUserVisibleData(items: eClearUserVisibleDataItemsAll);
393 m_parent->SetFormat(format);
394 }
395 this->ValueObject::SetFormat(format);
396 this->ClearUserVisibleData(items: eClearUserVisibleDataItemsAll);
397}
398
399void ValueObjectSynthetic::SetPreferredDisplayLanguage(
400 lldb::LanguageType lang) {
401 this->ValueObject::SetPreferredDisplayLanguage(lang);
402 if (m_parent)
403 m_parent->SetPreferredDisplayLanguage(lang);
404}
405
406lldb::LanguageType ValueObjectSynthetic::GetPreferredDisplayLanguage() {
407 if (m_preferred_display_language == lldb::eLanguageTypeUnknown) {
408 if (m_parent)
409 return m_parent->GetPreferredDisplayLanguage();
410 return lldb::eLanguageTypeUnknown;
411 } else
412 return m_preferred_display_language;
413}
414
415bool ValueObjectSynthetic::IsSyntheticChildrenGenerated() {
416 if (m_parent)
417 return m_parent->IsSyntheticChildrenGenerated();
418 return false;
419}
420
421void ValueObjectSynthetic::SetSyntheticChildrenGenerated(bool b) {
422 if (m_parent)
423 m_parent->SetSyntheticChildrenGenerated(b);
424 this->ValueObject::SetSyntheticChildrenGenerated(b);
425}
426
427bool ValueObjectSynthetic::GetDeclaration(Declaration &decl) {
428 if (m_parent)
429 return m_parent->GetDeclaration(decl);
430
431 return ValueObject::GetDeclaration(decl);
432}
433
434uint64_t ValueObjectSynthetic::GetLanguageFlags() {
435 if (m_parent)
436 return m_parent->GetLanguageFlags();
437 return this->ValueObject::GetLanguageFlags();
438}
439
440void ValueObjectSynthetic::SetLanguageFlags(uint64_t flags) {
441 if (m_parent)
442 m_parent->SetLanguageFlags(flags);
443 else
444 this->ValueObject::SetLanguageFlags(flags);
445}
446

source code of lldb/source/ValueObject/ValueObjectSyntheticFilter.cpp