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/Core/ValueObjectDynamicValue.h"
10#include "lldb/Core/Value.h"
11#include "lldb/Core/ValueObject.h"
12#include "lldb/Symbol/CompilerType.h"
13#include "lldb/Symbol/Type.h"
14#include "lldb/Target/ExecutionContext.h"
15#include "lldb/Target/LanguageRuntime.h"
16#include "lldb/Target/Process.h"
17#include "lldb/Target/Target.h"
18#include "lldb/Utility/DataExtractor.h"
19#include "lldb/Utility/LLDBLog.h"
20#include "lldb/Utility/Log.h"
21#include "lldb/Utility/Scalar.h"
22#include "lldb/Utility/Status.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
101std::optional<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();
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
149 LanguageRuntime *runtime = nullptr;
150
151 lldb::LanguageType known_type = m_parent->GetObjectRuntimeLanguage();
152 if (known_type != lldb::eLanguageTypeUnknown &&
153 known_type != lldb::eLanguageTypeC) {
154 runtime = process->GetLanguageRuntime(language: known_type);
155 if (auto *preferred_runtime =
156 runtime->GetPreferredLanguageRuntime(in_value&: *m_parent)) {
157 // Try the preferred runtime first.
158 found_dynamic_type = preferred_runtime->GetDynamicTypeAndAddress(
159 in_value&: *m_parent, use_dynamic: m_use_dynamic, class_type_or_name, address&: dynamic_address,
160 value_type);
161 if (found_dynamic_type)
162 // Set the operative `runtime` for later use in this function.
163 runtime = preferred_runtime;
164 }
165 if (!found_dynamic_type)
166 // Fallback to the runtime for `known_type`.
167 found_dynamic_type = runtime->GetDynamicTypeAndAddress(
168 in_value&: *m_parent, use_dynamic: m_use_dynamic, class_type_or_name, address&: dynamic_address,
169 value_type);
170 } else {
171 runtime = process->GetLanguageRuntime(language: lldb::eLanguageTypeC_plus_plus);
172 if (runtime)
173 found_dynamic_type = runtime->GetDynamicTypeAndAddress(
174 in_value&: *m_parent, use_dynamic: m_use_dynamic, class_type_or_name, address&: dynamic_address,
175 value_type);
176
177 if (!found_dynamic_type) {
178 runtime = process->GetLanguageRuntime(language: lldb::eLanguageTypeObjC);
179 if (runtime)
180 found_dynamic_type = runtime->GetDynamicTypeAndAddress(
181 in_value&: *m_parent, use_dynamic: m_use_dynamic, class_type_or_name, address&: dynamic_address,
182 value_type);
183 }
184 }
185
186 // Getting the dynamic value may have run the program a bit, and so marked us
187 // as needing updating, but we really don't...
188
189 m_update_point.SetUpdated();
190
191 if (runtime && found_dynamic_type) {
192 if (class_type_or_name.HasType()) {
193 m_type_impl =
194 TypeImpl(m_parent->GetCompilerType(),
195 runtime->FixUpDynamicType(type_and_or_name: class_type_or_name, static_value&: *m_parent)
196 .GetCompilerType());
197 } else {
198 m_type_impl.Clear();
199 }
200 } else {
201 m_type_impl.Clear();
202 }
203
204 // If we don't have a dynamic type, set ourselves to be invalid and return
205 // false. We used to try to produce a dynamic ValueObject that behaved "like"
206 // its parent, but that failed for ValueObjectConstResult, which is too
207 // complex a beast to try to emulate. If we return an invalid ValueObject,
208 // clients will end up getting the static value instead, which behaves
209 // correctly.
210 if (!found_dynamic_type) {
211 if (m_dynamic_type_info)
212 SetValueDidChange(true);
213 ClearDynamicTypeInformation();
214 m_dynamic_type_info.Clear();
215 m_error.SetErrorString("no dynamic type found");
216 return false;
217 }
218
219 Value old_value(m_value);
220
221 Log *log = GetLog(mask: LLDBLog::Types);
222
223 bool has_changed_type = false;
224
225 if (!m_dynamic_type_info) {
226 m_dynamic_type_info = class_type_or_name;
227 has_changed_type = true;
228 } else if (class_type_or_name != m_dynamic_type_info) {
229 // We are another type, we need to tear down our children...
230 m_dynamic_type_info = class_type_or_name;
231 SetValueDidChange(true);
232 has_changed_type = true;
233 }
234
235 if (has_changed_type)
236 ClearDynamicTypeInformation();
237
238 if (!m_address.IsValid() || m_address != dynamic_address) {
239 if (m_address.IsValid())
240 SetValueDidChange(true);
241
242 // We've moved, so we should be fine...
243 m_address = dynamic_address;
244 lldb::TargetSP target_sp(GetTargetSP());
245 lldb::addr_t load_address = m_address.GetLoadAddress(target: target_sp.get());
246 m_value.GetScalar() = load_address;
247 }
248
249 if (runtime)
250 m_dynamic_type_info =
251 runtime->FixUpDynamicType(type_and_or_name: m_dynamic_type_info, static_value&: *m_parent);
252
253 m_value.SetCompilerType(m_dynamic_type_info.GetCompilerType());
254
255 m_value.SetValueType(value_type);
256
257 if (has_changed_type && log)
258 LLDB_LOGF(log, "[%s %p] has a new dynamic type %s", GetName().GetCString(),
259 static_cast<void *>(this), GetTypeName().GetCString());
260
261 if (m_address.IsValid() && m_dynamic_type_info) {
262 // The variable value is in the Scalar value inside the m_value. We can
263 // point our m_data right to it.
264 m_error = m_value.GetValueAsData(exe_ctx: &exe_ctx, data&: m_data, module: GetModule().get());
265 if (m_error.Success()) {
266 if (!CanProvideValue()) {
267 // this value object represents an aggregate type whose children have
268 // values, but this object does not. So we say we are changed if our
269 // location has changed.
270 SetValueDidChange(m_value.GetValueType() != old_value.GetValueType() ||
271 m_value.GetScalar() != old_value.GetScalar());
272 }
273
274 SetValueIsValid(true);
275 return true;
276 }
277 }
278
279 // We get here if we've failed above...
280 SetValueIsValid(false);
281 return false;
282}
283
284bool ValueObjectDynamicValue::IsInScope() { return m_parent->IsInScope(); }
285
286bool ValueObjectDynamicValue::SetValueFromCString(const char *value_str,
287 Status &error) {
288 if (!UpdateValueIfNeeded(update_format: false)) {
289 error.SetErrorString("unable to read value");
290 return false;
291 }
292
293 uint64_t my_value = GetValueAsUnsigned(UINT64_MAX);
294 uint64_t parent_value = m_parent->GetValueAsUnsigned(UINT64_MAX);
295
296 if (my_value == UINT64_MAX || parent_value == UINT64_MAX) {
297 error.SetErrorString("unable to read value");
298 return false;
299 }
300
301 // if we are at an offset from our parent, in order to set ourselves
302 // correctly we would need to change the new value so that it refers to the
303 // correct dynamic type. we choose not to deal with that - if anything more
304 // than a value overwrite is required, you should be using the expression
305 // parser instead of the value editing facility
306 if (my_value != parent_value) {
307 // but NULL'ing out a value should always be allowed
308 if (strcmp(s1: value_str, s2: "0")) {
309 error.SetErrorString(
310 "unable to modify dynamic value, use 'expression' command");
311 return false;
312 }
313 }
314
315 bool ret_val = m_parent->SetValueFromCString(value_str, error);
316 SetNeedsUpdate();
317 return ret_val;
318}
319
320bool ValueObjectDynamicValue::SetData(DataExtractor &data, Status &error) {
321 if (!UpdateValueIfNeeded(update_format: false)) {
322 error.SetErrorString("unable to read value");
323 return false;
324 }
325
326 uint64_t my_value = GetValueAsUnsigned(UINT64_MAX);
327 uint64_t parent_value = m_parent->GetValueAsUnsigned(UINT64_MAX);
328
329 if (my_value == UINT64_MAX || parent_value == UINT64_MAX) {
330 error.SetErrorString("unable to read value");
331 return false;
332 }
333
334 // if we are at an offset from our parent, in order to set ourselves
335 // correctly we would need to change the new value so that it refers to the
336 // correct dynamic type. we choose not to deal with that - if anything more
337 // than a value overwrite is required, you should be using the expression
338 // parser instead of the value editing facility
339 if (my_value != parent_value) {
340 // but NULL'ing out a value should always be allowed
341 lldb::offset_t offset = 0;
342
343 if (data.GetAddress(offset_ptr: &offset) != 0) {
344 error.SetErrorString(
345 "unable to modify dynamic value, use 'expression' command");
346 return false;
347 }
348 }
349
350 bool ret_val = m_parent->SetData(data, error);
351 SetNeedsUpdate();
352 return ret_val;
353}
354
355void ValueObjectDynamicValue::SetPreferredDisplayLanguage(
356 lldb::LanguageType lang) {
357 this->ValueObject::SetPreferredDisplayLanguage(lang);
358 if (m_parent)
359 m_parent->SetPreferredDisplayLanguage(lang);
360}
361
362lldb::LanguageType ValueObjectDynamicValue::GetPreferredDisplayLanguage() {
363 if (m_preferred_display_language == lldb::eLanguageTypeUnknown) {
364 if (m_parent)
365 return m_parent->GetPreferredDisplayLanguage();
366 return lldb::eLanguageTypeUnknown;
367 } else
368 return m_preferred_display_language;
369}
370
371bool ValueObjectDynamicValue::IsSyntheticChildrenGenerated() {
372 if (m_parent)
373 return m_parent->IsSyntheticChildrenGenerated();
374 return false;
375}
376
377void ValueObjectDynamicValue::SetSyntheticChildrenGenerated(bool b) {
378 if (m_parent)
379 m_parent->SetSyntheticChildrenGenerated(b);
380 this->ValueObject::SetSyntheticChildrenGenerated(b);
381}
382
383bool ValueObjectDynamicValue::GetDeclaration(Declaration &decl) {
384 if (m_parent)
385 return m_parent->GetDeclaration(decl);
386
387 return ValueObject::GetDeclaration(decl);
388}
389
390uint64_t ValueObjectDynamicValue::GetLanguageFlags() {
391 if (m_parent)
392 return m_parent->GetLanguageFlags();
393 return this->ValueObject::GetLanguageFlags();
394}
395
396void ValueObjectDynamicValue::SetLanguageFlags(uint64_t flags) {
397 if (m_parent)
398 m_parent->SetLanguageFlags(flags);
399 else
400 this->ValueObject::SetLanguageFlags(flags);
401}
402

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