1//===-- ValueObjectDynamicValue.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/ValueObjectDynamicValue.h"
10#include "lldb/Core/Value.h"
11#include "lldb/Symbol/CompilerType.h"
12#include "lldb/Symbol/Type.h"
13#include "lldb/Target/ExecutionContext.h"
14#include "lldb/Target/LanguageRuntime.h"
15#include "lldb/Target/Process.h"
16#include "lldb/Target/Target.h"
17#include "lldb/Utility/DataExtractor.h"
18#include "lldb/Utility/LLDBLog.h"
19#include "lldb/Utility/Log.h"
20#include "lldb/Utility/Scalar.h"
21#include "lldb/Utility/Status.h"
22#include "lldb/ValueObject/ValueObject.h"
23#include "lldb/lldb-types.h"
24
25#include <cstring>
26#include <optional>
27namespace lldb_private {
28class Declaration;
29}
30
31using namespace lldb_private;
32
33ValueObjectDynamicValue::ValueObjectDynamicValue(
34 ValueObject &parent, lldb::DynamicValueType use_dynamic)
35 : ValueObject(parent), m_address(), m_dynamic_type_info(),
36 m_use_dynamic(use_dynamic) {
37 SetName(parent.GetName());
38}
39
40CompilerType ValueObjectDynamicValue::GetCompilerTypeImpl() {
41 const bool success = UpdateValueIfNeeded(update_format: false);
42 if (success) {
43 if (m_dynamic_type_info.HasType())
44 return m_value.GetCompilerType();
45 else
46 return m_parent->GetCompilerType();
47 }
48 return m_parent->GetCompilerType();
49}
50
51ConstString ValueObjectDynamicValue::GetTypeName() {
52 const bool success = UpdateValueIfNeeded(update_format: false);
53 if (success) {
54 if (m_dynamic_type_info.HasName())
55 return m_dynamic_type_info.GetName();
56 }
57 return m_parent->GetTypeName();
58}
59
60TypeImpl ValueObjectDynamicValue::GetTypeImpl() {
61 const bool success = UpdateValueIfNeeded(update_format: false);
62 if (success && m_type_impl.IsValid()) {
63 return m_type_impl;
64 }
65 return m_parent->GetTypeImpl();
66}
67
68ConstString ValueObjectDynamicValue::GetQualifiedTypeName() {
69 const bool success = UpdateValueIfNeeded(update_format: false);
70 if (success) {
71 if (m_dynamic_type_info.HasName())
72 return m_dynamic_type_info.GetName();
73 }
74 return m_parent->GetQualifiedTypeName();
75}
76
77ConstString ValueObjectDynamicValue::GetDisplayTypeName() {
78 const bool success = UpdateValueIfNeeded(update_format: false);
79 if (success) {
80 if (m_dynamic_type_info.HasType())
81 return GetCompilerType().GetDisplayTypeName();
82 if (m_dynamic_type_info.HasName())
83 return m_dynamic_type_info.GetName();
84 }
85 return m_parent->GetDisplayTypeName();
86}
87
88llvm::Expected<uint32_t>
89ValueObjectDynamicValue::CalculateNumChildren(uint32_t max) {
90 const bool success = UpdateValueIfNeeded(update_format: false);
91 if (success && m_dynamic_type_info.HasType()) {
92 ExecutionContext exe_ctx(GetExecutionContextRef());
93 auto children_count = GetCompilerType().GetNumChildren(omit_empty_base_classes: true, exe_ctx: &exe_ctx);
94 if (!children_count)
95 return children_count;
96 return *children_count <= max ? *children_count : max;
97 } else
98 return m_parent->GetNumChildren(max);
99}
100
101llvm::Expected<uint64_t> ValueObjectDynamicValue::GetByteSize() {
102 const bool success = UpdateValueIfNeeded(update_format: false);
103 if (success && m_dynamic_type_info.HasType()) {
104 ExecutionContext exe_ctx(GetExecutionContextRef());
105 return m_value.GetValueByteSize(error_ptr: nullptr, exe_ctx: &exe_ctx);
106 } else
107 return m_parent->GetByteSize();
108}
109
110lldb::ValueType ValueObjectDynamicValue::GetValueType() const {
111 return m_parent->GetValueType();
112}
113
114bool ValueObjectDynamicValue::UpdateValue() {
115 SetValueIsValid(false);
116 m_error.Clear();
117
118 if (!m_parent->UpdateValueIfNeeded(update_format: false)) {
119 // The dynamic value failed to get an error, pass the error along
120 if (m_error.Success() && m_parent->GetError().Fail())
121 m_error = m_parent->GetError().Clone();
122 return false;
123 }
124
125 // Setting our type_sp to NULL will route everything back through our parent
126 // which is equivalent to not using dynamic values.
127 if (m_use_dynamic == lldb::eNoDynamicValues) {
128 m_dynamic_type_info.Clear();
129 return true;
130 }
131
132 ExecutionContext exe_ctx(GetExecutionContextRef());
133 Target *target = exe_ctx.GetTargetPtr();
134 if (target) {
135 m_data.SetByteOrder(target->GetArchitecture().GetByteOrder());
136 m_data.SetAddressByteSize(target->GetArchitecture().GetAddressByteSize());
137 }
138
139 // First make sure our Type and/or Address haven't changed:
140 Process *process = exe_ctx.GetProcessPtr();
141 if (!process)
142 return false;
143
144 TypeAndOrName class_type_or_name;
145 Address dynamic_address;
146 bool found_dynamic_type = false;
147 Value::ValueType value_type;
148 llvm::ArrayRef<uint8_t> local_buffer;
149
150 LanguageRuntime *runtime = nullptr;
151
152 lldb::LanguageType known_type = m_parent->GetObjectRuntimeLanguage();
153 if (known_type != lldb::eLanguageTypeUnknown &&
154 known_type != lldb::eLanguageTypeC) {
155 runtime = process->GetLanguageRuntime(language: known_type);
156 if (auto *preferred_runtime =
157 runtime->GetPreferredLanguageRuntime(in_value&: *m_parent)) {
158 // Try the preferred runtime first.
159 found_dynamic_type = preferred_runtime->GetDynamicTypeAndAddress(
160 in_value&: *m_parent, use_dynamic: m_use_dynamic, class_type_or_name, address&: dynamic_address,
161 value_type, local_buffer);
162 if (found_dynamic_type)
163 // Set the operative `runtime` for later use in this function.
164 runtime = preferred_runtime;
165 }
166 if (!found_dynamic_type)
167 // Fallback to the runtime for `known_type`.
168 found_dynamic_type = runtime->GetDynamicTypeAndAddress(
169 in_value&: *m_parent, use_dynamic: m_use_dynamic, class_type_or_name, address&: dynamic_address,
170 value_type, local_buffer);
171 } else {
172 runtime = process->GetLanguageRuntime(language: lldb::eLanguageTypeC_plus_plus);
173 if (runtime)
174 found_dynamic_type = runtime->GetDynamicTypeAndAddress(
175 in_value&: *m_parent, use_dynamic: m_use_dynamic, class_type_or_name, address&: dynamic_address,
176 value_type, local_buffer);
177
178 if (!found_dynamic_type) {
179 runtime = process->GetLanguageRuntime(language: lldb::eLanguageTypeObjC);
180 if (runtime)
181 found_dynamic_type = runtime->GetDynamicTypeAndAddress(
182 in_value&: *m_parent, use_dynamic: m_use_dynamic, class_type_or_name, address&: dynamic_address,
183 value_type, local_buffer);
184 }
185 }
186
187 // Getting the dynamic value may have run the program a bit, and so marked us
188 // as needing updating, but we really don't...
189
190 m_update_point.SetUpdated();
191
192 if (runtime && found_dynamic_type) {
193 if (class_type_or_name.HasType()) {
194 m_type_impl =
195 TypeImpl(m_parent->GetCompilerType(),
196 runtime->FixUpDynamicType(type_and_or_name: class_type_or_name, static_value&: *m_parent)
197 .GetCompilerType());
198 } else {
199 m_type_impl.Clear();
200 }
201 } else {
202 m_type_impl.Clear();
203 }
204
205 // If we don't have a dynamic type, set ourselves to be invalid and return
206 // false. We used to try to produce a dynamic ValueObject that behaved "like"
207 // its parent, but that failed for ValueObjectConstResult, which is too
208 // complex a beast to try to emulate. If we return an invalid ValueObject,
209 // clients will end up getting the static value instead, which behaves
210 // correctly.
211 if (!found_dynamic_type) {
212 if (m_dynamic_type_info)
213 SetValueDidChange(true);
214 ClearDynamicTypeInformation();
215 m_dynamic_type_info.Clear();
216 m_error = Status::FromErrorString(str: "no dynamic type found");
217 return false;
218 }
219
220 Value old_value(m_value);
221
222 Log *log = GetLog(mask: LLDBLog::Types);
223
224 bool has_changed_type = false;
225
226 if (!m_dynamic_type_info) {
227 m_dynamic_type_info = class_type_or_name;
228 has_changed_type = true;
229 } else if (class_type_or_name != m_dynamic_type_info) {
230 // We are another type, we need to tear down our children...
231 m_dynamic_type_info = class_type_or_name;
232 SetValueDidChange(true);
233 has_changed_type = true;
234 }
235
236 if (has_changed_type)
237 ClearDynamicTypeInformation();
238
239 if (!m_address.IsValid() || m_address != dynamic_address) {
240 if (m_address.IsValid())
241 SetValueDidChange(true);
242
243 // If we found a host address, and the dynamic type fits in the local buffer
244 // that was found, point to that buffer. Later on this function will copy
245 // the buffer over.
246 if (value_type == Value::ValueType::HostAddress && !local_buffer.empty()) {
247 auto *exe_scope = exe_ctx.GetBestExecutionContextScope();
248 // If we found a host address but it doesn't fit in the buffer, there's
249 // nothing we can do.
250 if (local_buffer.size() <
251 llvm::expectedToOptional(
252 E: m_dynamic_type_info.GetCompilerType().GetByteSize(exe_scope))) {
253 SetValueIsValid(false);
254 return false;
255 }
256
257 m_value.GetScalar() = (uint64_t)local_buffer.data();
258 m_address = LLDB_INVALID_ADDRESS;
259 } else {
260 // Otherwise we have a legitimate address on the target. Point to the load
261 // address.
262 m_address = dynamic_address;
263 lldb::TargetSP target_sp(GetTargetSP());
264 lldb::addr_t load_address = m_address.GetLoadAddress(target: target_sp.get());
265 m_value.GetScalar() = load_address;
266 }
267 }
268
269 if (runtime)
270 m_dynamic_type_info =
271 runtime->FixUpDynamicType(type_and_or_name: m_dynamic_type_info, static_value&: *m_parent);
272
273 m_value.SetCompilerType(m_dynamic_type_info.GetCompilerType());
274
275 m_value.SetValueType(value_type);
276
277 if (has_changed_type && log)
278 LLDB_LOGF(log, "[%s %p] has a new dynamic type %s", GetName().GetCString(),
279 static_cast<void *>(this), GetTypeName().GetCString());
280
281 // m_address could be invalid but we could still have a local buffer
282 // containing the dynamic value.
283 if ((m_address.IsValid() ||
284 m_value.GetValueType() == Value::ValueType::HostAddress) &&
285 m_dynamic_type_info) {
286 // The variable value is in the Scalar value inside the m_value. We can
287 // point our m_data right to it.
288 m_error = m_value.GetValueAsData(exe_ctx: &exe_ctx, data&: m_data, module: GetModule().get());
289 if (m_error.Success()) {
290 if (!CanProvideValue()) {
291 // this value object represents an aggregate type whose children have
292 // values, but this object does not. So we say we are changed if our
293 // location has changed.
294 SetValueDidChange(m_value.GetValueType() != old_value.GetValueType() ||
295 m_value.GetScalar() != old_value.GetScalar());
296 }
297
298 SetValueIsValid(true);
299 return true;
300 }
301 }
302
303 // We get here if we've failed above...
304 SetValueIsValid(false);
305 return false;
306}
307
308bool ValueObjectDynamicValue::IsInScope() { return m_parent->IsInScope(); }
309
310bool ValueObjectDynamicValue::SetValueFromCString(const char *value_str,
311 Status &error) {
312 if (!UpdateValueIfNeeded(update_format: false)) {
313 error = Status::FromErrorString(str: "unable to read value");
314 return false;
315 }
316
317 uint64_t my_value = GetValueAsUnsigned(UINT64_MAX);
318 uint64_t parent_value = m_parent->GetValueAsUnsigned(UINT64_MAX);
319
320 if (my_value == UINT64_MAX || parent_value == UINT64_MAX) {
321 error = Status::FromErrorString(str: "unable to read value");
322 return false;
323 }
324
325 // if we are at an offset from our parent, in order to set ourselves
326 // correctly we would need to change the new value so that it refers to the
327 // correct dynamic type. we choose not to deal with that - if anything more
328 // than a value overwrite is required, you should be using the expression
329 // parser instead of the value editing facility
330 if (my_value != parent_value) {
331 // but NULL'ing out a value should always be allowed
332 if (strcmp(s1: value_str, s2: "0")) {
333 error = Status::FromErrorString(
334 str: "unable to modify dynamic value, use 'expression' command");
335 return false;
336 }
337 }
338
339 bool ret_val = m_parent->SetValueFromCString(value_str, error);
340 SetNeedsUpdate();
341 return ret_val;
342}
343
344bool ValueObjectDynamicValue::SetData(DataExtractor &data, Status &error) {
345 if (!UpdateValueIfNeeded(update_format: false)) {
346 error = Status::FromErrorString(str: "unable to read value");
347 return false;
348 }
349
350 uint64_t my_value = GetValueAsUnsigned(UINT64_MAX);
351 uint64_t parent_value = m_parent->GetValueAsUnsigned(UINT64_MAX);
352
353 if (my_value == UINT64_MAX || parent_value == UINT64_MAX) {
354 error = Status::FromErrorString(str: "unable to read value");
355 return false;
356 }
357
358 // if we are at an offset from our parent, in order to set ourselves
359 // correctly we would need to change the new value so that it refers to the
360 // correct dynamic type. we choose not to deal with that - if anything more
361 // than a value overwrite is required, you should be using the expression
362 // parser instead of the value editing facility
363 if (my_value != parent_value) {
364 // but NULL'ing out a value should always be allowed
365 lldb::offset_t offset = 0;
366
367 if (data.GetAddress(offset_ptr: &offset) != 0) {
368 error = Status::FromErrorString(
369 str: "unable to modify dynamic value, use 'expression' command");
370 return false;
371 }
372 }
373
374 bool ret_val = m_parent->SetData(data, error);
375 SetNeedsUpdate();
376 return ret_val;
377}
378
379void ValueObjectDynamicValue::SetPreferredDisplayLanguage(
380 lldb::LanguageType lang) {
381 this->ValueObject::SetPreferredDisplayLanguage(lang);
382 if (m_parent)
383 m_parent->SetPreferredDisplayLanguage(lang);
384}
385
386lldb::LanguageType ValueObjectDynamicValue::GetPreferredDisplayLanguage() {
387 if (m_preferred_display_language == lldb::eLanguageTypeUnknown) {
388 if (m_parent)
389 return m_parent->GetPreferredDisplayLanguage();
390 return lldb::eLanguageTypeUnknown;
391 } else
392 return m_preferred_display_language;
393}
394
395bool ValueObjectDynamicValue::IsSyntheticChildrenGenerated() {
396 if (m_parent)
397 return m_parent->IsSyntheticChildrenGenerated();
398 return false;
399}
400
401void ValueObjectDynamicValue::SetSyntheticChildrenGenerated(bool b) {
402 if (m_parent)
403 m_parent->SetSyntheticChildrenGenerated(b);
404 this->ValueObject::SetSyntheticChildrenGenerated(b);
405}
406
407bool ValueObjectDynamicValue::GetDeclaration(Declaration &decl) {
408 if (m_parent)
409 return m_parent->GetDeclaration(decl);
410
411 return ValueObject::GetDeclaration(decl);
412}
413
414uint64_t ValueObjectDynamicValue::GetLanguageFlags() {
415 if (m_parent)
416 return m_parent->GetLanguageFlags();
417 return this->ValueObject::GetLanguageFlags();
418}
419
420void ValueObjectDynamicValue::SetLanguageFlags(uint64_t flags) {
421 if (m_parent)
422 m_parent->SetLanguageFlags(flags);
423 else
424 this->ValueObject::SetLanguageFlags(flags);
425}
426

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