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[lldb] Make ValueObjectDynamicValue::UpdateValue() point to a host b… (#125143)
…uffer ValueObjectDynamicValue::UpdateValue() assumes that the dynamic type found by GetDynamicTypeAndAddress() would return an address in the inferior. This commit makes it so it can deal with being passed a host address instead. This is needed downstream by the Swift fork. rdar://143357274
1 parent 6f50849 commit 0cbc498

17 files changed

+342
-41
lines changed

‎lldb/include/lldb/Target/LanguageRuntime.h

Lines changed: 10 additions & 6 deletions
Original file line numberDiff line numberDiff line change
@@ -105,12 +105,16 @@ class LanguageRuntime : public Runtime, public PluginInterface {
105105
"language doesn't support getting vtable information");
106106
}
107107

108-
// this call should return true if it could set the name and/or the type
109-
virtual bool GetDynamicTypeAndAddress(ValueObject &in_value,
110-
lldb::DynamicValueType use_dynamic,
111-
TypeAndOrName &class_type_or_name,
112-
Address &address,
113-
Value::ValueType &value_type) = 0;
108+
/// This call should return true if it could set the name and/or the type
109+
/// Sets address to the address of the dynamic type if value_type is set to
110+
/// a file or load address. Sets local_buffer to a buffer containing the data
111+
/// of the dynamic type if value_type is set to a host address. Callers should
112+
/// copy local_buffer over into their own buffer if they want to keep the data
113+
/// alive.
114+
virtual bool GetDynamicTypeAndAddress(
115+
ValueObject &in_value, lldb::DynamicValueType use_dynamic,
116+
TypeAndOrName &class_type_or_name, Address &address,
117+
Value::ValueType &value_type, llvm::ArrayRef<uint8_t> &local_buffer) = 0;
114118

115119
// This call should return a CompilerType given a generic type name and an
116120
// ExecutionContextScope in which one can actually fetch any specialization

‎lldb/include/lldb/ValueObject/ValueObject.h

Lines changed: 12 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -865,6 +865,18 @@ class ValueObject {
865865

866866
virtual void SetLanguageFlags(uint64_t flags) { m_language_flags = flags; }
867867

868+
/// Returns the size of the local buffer if it's available.
869+
/// \return
870+
/// The size of the local buffer if this value object's value points to a
871+
/// host address, and if that size can be determined. Otherwise, returns
872+
/// LLDB_INVALID_ADDRESS.
873+
///
874+
/// TODO: Because a ValueObject's Value can point to any arbitrary memory
875+
/// location, it is possible that the size of the local buffer can't be
876+
/// determined at all. See the comment in Value::m_value for a more thorough
877+
/// explanation of why that is.
878+
uint64_t GetLocalBufferSize();
879+
868880
protected:
869881
typedef ClusterManager<ValueObject> ValueObjectManager;
870882

‎lldb/source/Plugins/LanguageRuntime/CPlusPlus/ItaniumABI/ItaniumABILanguageRuntime.cpp

Lines changed: 1 addition & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -289,7 +289,7 @@ llvm::Expected<LanguageRuntime::VTableInfo>
289289
bool ItaniumABILanguageRuntime::GetDynamicTypeAndAddress(
290290
ValueObject &in_value, lldb::DynamicValueType use_dynamic,
291291
TypeAndOrName &class_type_or_name, Address &dynamic_address,
292-
Value::ValueType &value_type) {
292+
Value::ValueType &value_type, llvm::ArrayRef<uint8_t> &local_buffer) {
293293
// For Itanium, if the type has a vtable pointer in the object, it will be at
294294
// offset 0 in the object. That will point to the "address point" within the
295295
// vtable (not the beginning of the vtable.) We can then look up the symbol

‎lldb/source/Plugins/LanguageRuntime/CPlusPlus/ItaniumABI/ItaniumABILanguageRuntime.h

Lines changed: 2 additions & 2 deletions
Original file line numberDiff line numberDiff line change
@@ -54,8 +54,8 @@ class ItaniumABILanguageRuntime : public lldb_private::CPPLanguageRuntime {
5454
bool GetDynamicTypeAndAddress(ValueObject &in_value,
5555
lldb::DynamicValueType use_dynamic,
5656
TypeAndOrName &class_type_or_name,
57-
Address &address,
58-
Value::ValueType &value_type) override;
57+
Address &address, Value::ValueType &value_type,
58+
llvm::ArrayRef<uint8_t> &local_buffer) override;
5959

6060
TypeAndOrName FixUpDynamicType(const TypeAndOrName &type_and_or_name,
6161
ValueObject &static_value) override;

‎lldb/source/Plugins/LanguageRuntime/ObjC/AppleObjCRuntime/AppleObjCRuntime.cpp

Lines changed: 1 addition & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -276,7 +276,7 @@ bool AppleObjCRuntime::CouldHaveDynamicValue(ValueObject &in_value) {
276276
bool AppleObjCRuntime::GetDynamicTypeAndAddress(
277277
ValueObject &in_value, lldb::DynamicValueType use_dynamic,
278278
TypeAndOrName &class_type_or_name, Address &address,
279-
Value::ValueType &value_type) {
279+
Value::ValueType &value_type, llvm::ArrayRef<uint8_t> &local_buffer) {
280280
return false;
281281
}
282282

‎lldb/source/Plugins/LanguageRuntime/ObjC/AppleObjCRuntime/AppleObjCRuntime.h

Lines changed: 2 additions & 2 deletions
Original file line numberDiff line numberDiff line change
@@ -54,8 +54,8 @@ class AppleObjCRuntime : public lldb_private::ObjCLanguageRuntime {
5454
bool GetDynamicTypeAndAddress(ValueObject &in_value,
5555
lldb::DynamicValueType use_dynamic,
5656
TypeAndOrName &class_type_or_name,
57-
Address &address,
58-
Value::ValueType &value_type) override;
57+
Address &address, Value::ValueType &value_type,
58+
llvm::ArrayRef<uint8_t> &local_buffer) override;
5959

6060
TypeAndOrName FixUpDynamicType(const TypeAndOrName &type_and_or_name,
6161
ValueObject &static_value) override;

‎lldb/source/Plugins/LanguageRuntime/ObjC/AppleObjCRuntime/AppleObjCRuntimeV1.cpp

Lines changed: 1 addition & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -48,7 +48,7 @@ AppleObjCRuntimeV1::AppleObjCRuntimeV1(Process *process)
4848
bool AppleObjCRuntimeV1::GetDynamicTypeAndAddress(
4949
ValueObject &in_value, lldb::DynamicValueType use_dynamic,
5050
TypeAndOrName &class_type_or_name, Address &address,
51-
Value::ValueType &value_type) {
51+
Value::ValueType &value_type, llvm::ArrayRef<uint8_t> &local_buffer) {
5252
class_type_or_name.Clear();
5353
value_type = Value::ValueType::Scalar;
5454
if (CouldHaveDynamicValue(in_value)) {

‎lldb/source/Plugins/LanguageRuntime/ObjC/AppleObjCRuntime/AppleObjCRuntimeV1.h

Lines changed: 2 additions & 2 deletions
Original file line numberDiff line numberDiff line change
@@ -100,8 +100,8 @@ class AppleObjCRuntimeV1 : public AppleObjCRuntime {
100100
bool GetDynamicTypeAndAddress(ValueObject &in_value,
101101
lldb::DynamicValueType use_dynamic,
102102
TypeAndOrName &class_type_or_name,
103-
Address &address,
104-
Value::ValueType &value_type) override;
103+
Address &address, Value::ValueType &value_type,
104+
llvm::ArrayRef<uint8_t> &local_buffer) override;
105105

106106
llvm::Expected<std::unique_ptr<UtilityFunction>>
107107
CreateObjectChecker(std::string, ExecutionContext &exe_ctx) override;

‎lldb/source/Plugins/LanguageRuntime/ObjC/AppleObjCRuntime/AppleObjCRuntimeV2.cpp

Lines changed: 1 addition & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -770,7 +770,7 @@ AppleObjCRuntimeV2::GetPreferredLanguageRuntime(ValueObject &in_value) {
770770
bool AppleObjCRuntimeV2::GetDynamicTypeAndAddress(
771771
ValueObject &in_value, lldb::DynamicValueType use_dynamic,
772772
TypeAndOrName &class_type_or_name, Address &address,
773-
Value::ValueType &value_type) {
773+
Value::ValueType &value_type, llvm::ArrayRef<uint8_t> &local_buffer) {
774774
// We should never get here with a null process...
775775
assert(m_process != nullptr);
776776

‎lldb/source/Plugins/LanguageRuntime/ObjC/AppleObjCRuntime/AppleObjCRuntimeV2.h

Lines changed: 2 additions & 2 deletions
Original file line numberDiff line numberDiff line change
@@ -53,8 +53,8 @@ class AppleObjCRuntimeV2 : public AppleObjCRuntime {
5353
bool GetDynamicTypeAndAddress(ValueObject &in_value,
5454
lldb::DynamicValueType use_dynamic,
5555
TypeAndOrName &class_type_or_name,
56-
Address &address,
57-
Value::ValueType &value_type) override;
56+
Address &address, Value::ValueType &value_type,
57+
llvm::ArrayRef<uint8_t> &local_buffer) override;
5858

5959
llvm::Expected<std::unique_ptr<UtilityFunction>>
6060
CreateObjectChecker(std::string name, ExecutionContext &exe_ctx) override;

‎lldb/source/Plugins/LanguageRuntime/ObjC/GNUstepObjCRuntime/GNUstepObjCRuntime.cpp

Lines changed: 1 addition & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -127,7 +127,7 @@ bool GNUstepObjCRuntime::CouldHaveDynamicValue(ValueObject &in_value) {
127127
bool GNUstepObjCRuntime::GetDynamicTypeAndAddress(
128128
ValueObject &in_value, DynamicValueType use_dynamic,
129129
TypeAndOrName &class_type_or_name, Address &address,
130-
Value::ValueType &value_type) {
130+
Value::ValueType &value_type, llvm::ArrayRef<uint8_t> &local_buffer) {
131131
return false;
132132
}
133133

‎lldb/source/Plugins/LanguageRuntime/ObjC/GNUstepObjCRuntime/GNUstepObjCRuntime.h

Lines changed: 2 additions & 2 deletions
Original file line numberDiff line numberDiff line change
@@ -67,8 +67,8 @@ class GNUstepObjCRuntime : public lldb_private::ObjCLanguageRuntime {
6767
bool GetDynamicTypeAndAddress(ValueObject &in_value,
6868
lldb::DynamicValueType use_dynamic,
6969
TypeAndOrName &class_type_or_name,
70-
Address &address,
71-
Value::ValueType &value_type) override;
70+
Address &address, Value::ValueType &value_type,
71+
llvm::ArrayRef<uint8_t> &local_buffer) override;
7272

7373
TypeAndOrName FixUpDynamicType(const TypeAndOrName &type_and_or_name,
7474
ValueObject &static_value) override;

‎lldb/source/ValueObject/ValueObject.cpp

Lines changed: 16 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -849,6 +849,22 @@ bool ValueObject::SetData(DataExtractor &data, Status &error) {
849849
return true;
850850
}
851851

852+
uint64_t ValueObject::GetLocalBufferSize() {
853+
if (m_value.GetValueType() != Value::ValueType::HostAddress)
854+
return LLDB_INVALID_ADDRESS;
855+
auto start = m_value.GetScalar().ULongLong(LLDB_INVALID_ADDRESS);
856+
if (start == LLDB_INVALID_ADDRESS)
857+
return LLDB_INVALID_ADDRESS;
858+
// Does our pointer point to this value object's m_data buffer?
859+
if ((uint64_t)m_data.GetDataStart() == start)
860+
return m_data.GetByteSize();
861+
// Does our pointer point to the value's buffer?
862+
if ((uint64_t)m_value.GetBuffer().GetBytes() == start)
863+
return m_value.GetBuffer().GetByteSize();
864+
// Our pointer points to something else. We can't know what the size is.
865+
return LLDB_INVALID_ADDRESS;
866+
}
867+
852868
static bool CopyStringDataToBufferSP(const StreamString &source,
853869
lldb::WritableDataBufferSP &destination) {
854870
llvm::StringRef src = source.GetString();

‎lldb/source/ValueObject/ValueObjectDynamicValue.cpp

Lines changed: 33 additions & 10 deletions
Original file line numberDiff line numberDiff line change
@@ -145,6 +145,7 @@ bool ValueObjectDynamicValue::UpdateValue() {
145145
Address dynamic_address;
146146
bool found_dynamic_type = false;
147147
Value::ValueType value_type;
148+
llvm::ArrayRef<uint8_t> local_buffer;
148149

149150
LanguageRuntime *runtime = nullptr;
150151

@@ -157,7 +158,7 @@ bool ValueObjectDynamicValue::UpdateValue() {
157158
// Try the preferred runtime first.
158159
found_dynamic_type = preferred_runtime->GetDynamicTypeAndAddress(
159160
*m_parent, m_use_dynamic, class_type_or_name, dynamic_address,
160-
value_type);
161+
value_type, local_buffer);
161162
if (found_dynamic_type)
162163
// Set the operative `runtime` for later use in this function.
163164
runtime = preferred_runtime;
@@ -166,20 +167,20 @@ bool ValueObjectDynamicValue::UpdateValue() {
166167
// Fallback to the runtime for `known_type`.
167168
found_dynamic_type = runtime->GetDynamicTypeAndAddress(
168169
*m_parent, m_use_dynamic, class_type_or_name, dynamic_address,
169-
value_type);
170+
value_type, local_buffer);
170171
} else {
171172
runtime = process->GetLanguageRuntime(lldb::eLanguageTypeC_plus_plus);
172173
if (runtime)
173174
found_dynamic_type = runtime->GetDynamicTypeAndAddress(
174175
*m_parent, m_use_dynamic, class_type_or_name, dynamic_address,
175-
value_type);
176+
value_type, local_buffer);
176177

177178
if (!found_dynamic_type) {
178179
runtime = process->GetLanguageRuntime(lldb::eLanguageTypeObjC);
179180
if (runtime)
180181
found_dynamic_type = runtime->GetDynamicTypeAndAddress(
181182
*m_parent, m_use_dynamic, class_type_or_name, dynamic_address,
182-
value_type);
183+
value_type, local_buffer);
183184
}
184185
}
185186

@@ -239,11 +240,29 @@ bool ValueObjectDynamicValue::UpdateValue() {
239240
if (m_address.IsValid())
240241
SetValueDidChange(true);
241242

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_sp.get());
246-
m_value.GetScalar() = load_address;
243+
// If we found a host address, and the dynamic type fits in the local buffer
244+
// that was found, point to thar 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+
m_dynamic_type_info.GetCompilerType().GetByteSize(exe_scope)) {
252+
SetValueIsValid(false);
253+
return false;
254+
}
255+
256+
m_value.GetScalar() = (uint64_t)local_buffer.data();
257+
m_address = LLDB_INVALID_ADDRESS;
258+
} else {
259+
// Otherwise we have a legitimate address on the target. Point to the load
260+
// address.
261+
m_address = dynamic_address;
262+
lldb::TargetSP target_sp(GetTargetSP());
263+
lldb::addr_t load_address = m_address.GetLoadAddress(target_sp.get());
264+
m_value.GetScalar() = load_address;
265+
}
247266
}
248267

249268
if (runtime)
@@ -258,7 +277,11 @@ bool ValueObjectDynamicValue::UpdateValue() {
258277
LLDB_LOGF(log, "[%s %p] has a new dynamic type %s", GetName().GetCString(),
259278
static_cast<void *>(this), GetTypeName().GetCString());
260279

261-
if (m_address.IsValid() && m_dynamic_type_info) {
280+
// m_address could be invalid but we could still have a local buffer
281+
// containing the dynamic value.
282+
if ((m_address.IsValid() ||
283+
m_value.GetValueType() == Value::ValueType::HostAddress) &&
284+
m_dynamic_type_info) {
262285
// The variable value is in the Scalar value inside the m_value. We can
263286
// point our m_data right to it.
264287
m_error = m_value.GetValueAsData(&exe_ctx, m_data, GetModule().get());

‎lldb/unittests/TestingSupport/Symbol/ClangTestUtils.h

Lines changed: 12 additions & 10 deletions
Original file line numberDiff line numberDiff line change
@@ -21,20 +21,21 @@ inline clang::DeclarationName getDeclarationName(TypeSystemClang &ast,
2121
return ast.getASTContext().DeclarationNames.getIdentifier(&II);
2222
}
2323

24-
inline CompilerType createRecord(TypeSystemClang &ast, llvm::StringRef name) {
24+
inline CompilerType
25+
createRecord(TypeSystemClang &ast, llvm::StringRef name,
26+
lldb::LanguageType lang = lldb::LanguageType::eLanguageTypeC) {
2527
return ast.CreateRecordType(ast.getASTContext().getTranslationUnitDecl(),
2628
OptionalClangModuleID(),
27-
lldb::AccessType::eAccessPublic, name, 0,
28-
lldb::LanguageType::eLanguageTypeC);
29+
lldb::AccessType::eAccessPublic, name, 0, lang);
2930
}
3031

3132
/// Create a record with the given name and a field with the given type
3233
/// and name.
33-
inline CompilerType createRecordWithField(TypeSystemClang &ast,
34-
llvm::StringRef record_name,
35-
CompilerType field_type,
36-
llvm::StringRef field_name) {
37-
CompilerType t = createRecord(ast, record_name);
34+
inline CompilerType createRecordWithField(
35+
TypeSystemClang &ast, llvm::StringRef record_name, CompilerType field_type,
36+
llvm::StringRef field_name,
37+
lldb::LanguageType lang = lldb::LanguageType::eLanguageTypeC) {
38+
CompilerType t = createRecord(ast, record_name, lang);
3839

3940
TypeSystemClang::StartTagDeclarationDefinition(t);
4041
ast.AddFieldToRecordType(t, field_name, field_type,
@@ -63,12 +64,13 @@ struct SourceASTWithRecord {
6364
CompilerType record_type;
6465
clang::RecordDecl *record_decl = nullptr;
6566
clang::FieldDecl *field_decl = nullptr;
66-
SourceASTWithRecord() {
67+
SourceASTWithRecord(
68+
lldb::LanguageType lang = lldb::LanguageType::eLanguageTypeC) {
6769
holder = std::make_unique<TypeSystemClangHolder>("test ASTContext");
6870
ast = holder->GetAST();
6971
record_type = createRecordWithField(
7072
*ast, "Source", ast->GetBasicType(lldb::BasicType::eBasicTypeChar),
71-
"a_field");
73+
"a_field", lang);
7274
record_decl =
7375
llvm::cast<clang::RecordDecl>(ClangUtil::GetAsTagDecl(record_type));
7476
field_decl = *record_decl->fields().begin();

‎lldb/unittests/ValueObject/CMakeLists.txt

Lines changed: 1 addition & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -1,6 +1,7 @@
11
add_lldb_unittest(LLDBValueObjectTests
22
DumpValueObjectOptionsTests.cpp
33
DILLexerTests.cpp
4+
DynamicValueObjectLocalBuffer.cpp
45

56
LINK_LIBS
67
lldbValueObject

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