[lldb] Make GetDynamicTypeAndAddress() use host address if available

augusto2112 · augusto2112 · commit 829f2bc38dcc · 2025-02-07T10:06:38.000-08:00
If GetDynamicTypeAndAddress_Value cannot get back to the inferior address,
but does have a host address and buffer that fits the dynamic type,
return that.
diff --git a/lldb/source/Plugins/Language/Swift/SwiftLanguage.cpp b/lldb/source/Plugins/Language/Swift/SwiftLanguage.cpp
@@ -1114,13 +1114,14 @@ SwiftLanguage::GetHardcodedSynthetics() {
       TypeAndOrName type_or_name;
       Address address;
       Value::ValueType value_type;
+      llvm::ArrayRef<uint8_t> local_buffer;
       // Try to find the dynamic type of the Swift type.
       // TODO: find a way to get the dyamic value type from the
       // command.
       if (swift_runtime->GetDynamicTypeAndAddress(
               *casted_to_swift.get(),
               lldb::DynamicValueType::eDynamicCanRunTarget, type_or_name,
-              address, value_type)) {
+              address, value_type, local_buffer)) {
         if (type_or_name.HasCompilerType()) {
           swift_type = type_or_name.GetCompilerType();
           // Cast it to the more specific type.
@@ -1248,8 +1249,9 @@ SwiftLanguage::GetPossibleFormattersMatches(
   TypeAndOrName type_and_or_name;
   Address address;
   Value::ValueType value_type;
+  llvm::ArrayRef<uint8_t> local_buffer;
   if (!runtime->GetDynamicTypeAndAddress(valobj, use_dynamic, type_and_or_name,
-                                         address, value_type))
+                                         address, value_type, local_buffer))
     return result;
   if (ConstString name = type_and_or_name.GetName())
     result.push_back(
diff --git a/lldb/source/Plugins/LanguageRuntime/Swift/SwiftLanguageRuntime.h b/lldb/source/Plugins/LanguageRuntime/Swift/SwiftLanguageRuntime.h
@@ -242,8 +242,8 @@ class SwiftLanguageRuntime : public LanguageRuntime {
   bool GetDynamicTypeAndAddress(ValueObject &in_value,
                                 lldb::DynamicValueType use_dynamic,
                                 TypeAndOrName &class_type_or_name,
-                                Address &address,
-                                Value::ValueType &value_type) override;
+                                Address &address, Value::ValueType &value_type,
+                                llvm::ArrayRef<uint8_t> &local_buffer) override;
 
   CompilerType BindGenericTypeParameters(
       CompilerType unbound_type,
@@ -569,7 +569,8 @@ class SwiftLanguageRuntime : public LanguageRuntime {
                                       lldb::DynamicValueType use_dynamic,
                                       TypeAndOrName &class_type_or_name,
                                       Address &address,
-                                      Value::ValueType &value_type);
+                                      Value::ValueType &value_type,
+                                      llvm::ArrayRef<uint8_t> &local_buffer);
 #ifndef NDEBUG
   ConstString GetDynamicTypeName_ClassRemoteAST(ValueObject &in_value,
                                                 lldb::addr_t instance_ptr);
@@ -596,18 +597,18 @@ class SwiftLanguageRuntime : public LanguageRuntime {
                                       lldb::DynamicValueType use_dynamic,
                                       TypeAndOrName &class_type_or_name,
                                       Address &address,
-                                      Value::ValueType &value_type);
+                                      Value::ValueType &value_type,
+                                      llvm::ArrayRef<uint8_t> &local_buffer);
 
   bool GetDynamicTypeAndAddress_IndirectEnumCase(
       ValueObject &in_value, lldb::DynamicValueType use_dynamic,
       TypeAndOrName &class_type_or_name, Address &address,
-      Value::ValueType &value_type);
+      Value::ValueType &value_type, llvm::ArrayRef<uint8_t> &local_buffer);
 
-  bool GetDynamicTypeAndAddress_ClangType(ValueObject &in_value,
-                                          lldb::DynamicValueType use_dynamic,
-                                          TypeAndOrName &class_type_or_name,
-                                          Address &address,
-                                          Value::ValueType &value_type);
+  bool GetDynamicTypeAndAddress_ClangType(
+      ValueObject &in_value, lldb::DynamicValueType use_dynamic,
+      TypeAndOrName &class_type_or_name, Address &address,
+      Value::ValueType &value_type, llvm::ArrayRef<uint8_t> &local_buffer);
 
   /// Dynamic type resolution tends to want to generate scalar data -
   /// but there are caveats Per original comment here "Our address is
@@ -618,7 +619,8 @@ class SwiftLanguageRuntime : public LanguageRuntime {
   Value::ValueType GetValueType(ValueObject &in_value,
                                 CompilerType dynamic_type,
                                 Value::ValueType static_value_type,
-                                bool is_indirect_enum_case);
+                                bool is_indirect_enum_case,
+                                llvm::ArrayRef<uint8_t> &local_buffer);
 
   lldb::UnwindPlanSP
   GetRuntimeUnwindPlan(lldb::ProcessSP process_sp,
diff --git a/lldb/source/Plugins/LanguageRuntime/Swift/SwiftLanguageRuntimeDynamicTypeResolution.cpp b/lldb/source/Plugins/LanguageRuntime/Swift/SwiftLanguageRuntimeDynamicTypeResolution.cpp
@@ -1847,7 +1847,8 @@ static bool IsPrivateNSClass(NodePointer node) {
 bool SwiftLanguageRuntime::GetDynamicTypeAndAddress_Class(
     ValueObject &in_value, CompilerType class_type,
     lldb::DynamicValueType use_dynamic, TypeAndOrName &class_type_or_name,
-    Address &address, Value::ValueType &value_type) {
+    Address &address, Value::ValueType &value_type,
+    llvm::ArrayRef<uint8_t> &local_buffer) {
   AddressType address_type;
   lldb::addr_t instance_ptr = in_value.GetPointerValue(&address_type);
   value_type = Value::GetValueTypeFromAddressType(address_type);
@@ -1873,8 +1874,9 @@ bool SwiftLanguageRuntime::GetDynamicTypeAndAddress_Class(
     if (auto *objc_runtime =
             SwiftLanguageRuntime::GetObjCRuntime(GetProcess())) {
       Value::ValueType value_type;
-      if (objc_runtime->GetDynamicTypeAndAddress(
-              in_value, use_dynamic, class_type_or_name, address, value_type)) {
+      if (objc_runtime->GetDynamicTypeAndAddress(in_value, use_dynamic,
+                                                 class_type_or_name, address,
+                                                 value_type, local_buffer)) {
         bool found = false;
         // Return the most specific class which we can get the typeref.
         ForEachSuperClassType(in_value, [&](SuperClassType sc) -> bool {
@@ -2430,17 +2432,41 @@ bool SwiftLanguageRuntime::GetAbstractTypeName(StreamString &name,
 bool SwiftLanguageRuntime::GetDynamicTypeAndAddress_Value(
     ValueObject &in_value, CompilerType &bound_type,
     lldb::DynamicValueType use_dynamic, TypeAndOrName &class_type_or_name,
-    Address &address, Value::ValueType &value_type) {
+    Address &address, Value::ValueType &value_type,
+    llvm::ArrayRef<uint8_t> &local_buffer) {
+  auto static_type = in_value.GetCompilerType();
   value_type = Value::ValueType::Invalid;
   class_type_or_name.SetCompilerType(bound_type);
 
   ExecutionContext exe_ctx = in_value.GetExecutionContextRef().Lock(true);
+  ExecutionContextScope *exe_scope = exe_ctx.GetBestExecutionContextScope();
+  if (!exe_scope)
+    return false;
   std::optional<uint64_t> size =
       bound_type.GetByteSize(exe_ctx.GetBestExecutionContextScope());
   if (!size)
     return false;
   AddressType address_type;
   lldb::addr_t val_address = in_value.GetAddressOf(true, &address_type);
+  // If we couldn't find a load address, but the value object has a local
+  // buffer, use that.
+  if (val_address == LLDB_INVALID_ADDRESS && address_type == eAddressTypeHost) {
+    // Get the start and size of the local buffer.
+    auto start = in_value.GetValue().GetScalar().ULongLong();
+    auto local_buffer_size = in_value.GetLocalBufferSize();
+
+    // If we can't find the size of the local buffer we can't safely know if the
+    // dynamic type fits in it.
+    if (local_buffer_size == LLDB_INVALID_ADDRESS)
+      return false;
+    // If the dynamic type doesn't in the buffer we can't use it either.
+    if (local_buffer_size < bound_type.GetByteSize(exe_scope))
+      return false;
+
+    value_type = Value::GetValueTypeFromAddressType(address_type);
+    local_buffer = {(uint8_t *)start, local_buffer_size};
+    return true;
+  }
   if (*size && (!val_address || val_address == LLDB_INVALID_ADDRESS))
     return false;
 
@@ -2452,7 +2478,7 @@ bool SwiftLanguageRuntime::GetDynamicTypeAndAddress_Value(
 bool SwiftLanguageRuntime::GetDynamicTypeAndAddress_IndirectEnumCase(
     ValueObject &in_value, lldb::DynamicValueType use_dynamic,
     TypeAndOrName &class_type_or_name, Address &address,
-    Value::ValueType &value_type) {
+    Value::ValueType &value_type, llvm::ArrayRef<uint8_t> &local_buffer) {
   Status error;
   CompilerType child_type = in_value.GetCompilerType();
   class_type_or_name.SetCompilerType(child_type);
@@ -2484,7 +2510,7 @@ bool SwiftLanguageRuntime::GetDynamicTypeAndAddress_IndirectEnumCase(
       return false;
 
     return GetDynamicTypeAndAddress(*valobj_sp, use_dynamic, class_type_or_name,
-                                    address, value_type);
+                                    address, value_type, local_buffer);
   } else {
     // This is most likely a statically known type.
     address.SetLoadAddress(box_value, &GetProcess().GetTarget());
@@ -2510,7 +2536,8 @@ void SwiftLanguageRuntime::DumpTyperef(CompilerType type,
 
 Value::ValueType SwiftLanguageRuntime::GetValueType(
     ValueObject &in_value, CompilerType dynamic_type,
-    Value::ValueType static_value_type, bool is_indirect_enum_case) {
+    Value::ValueType static_value_type, bool is_indirect_enum_case,
+    llvm::ArrayRef<uint8_t> &local_buffer) {
   CompilerType static_type = in_value.GetCompilerType();
   Flags static_type_flags(static_type.GetTypeInfo());
   Flags dynamic_type_flags(dynamic_type.GetTypeInfo());
@@ -2564,6 +2591,12 @@ Value::ValueType SwiftLanguageRuntime::GetValueType(
       // If the data is not inlined, we have a pointer.
       return Value::ValueType::LoadAddress;
     }
+    // If we found a host address and the dynamic type fits in there, and
+    // this is not a pointer from an existential container, then this points to
+    // the local buffer.
+    if (static_value_type == Value::ValueType::HostAddress &&
+        !local_buffer.empty())
+      return static_value_type;
 
     if (static_type_flags.AllSet(eTypeIsSwift | eTypeIsGenericTypeParam)) {
       // if I am handling a non-pointer Swift type obtained from an archetype,
@@ -2671,7 +2704,7 @@ std::optional<SwiftNominalType> GetSwiftClass(ValueObject &valobj,
 bool SwiftLanguageRuntime::GetDynamicTypeAndAddress_ClangType(
     ValueObject &in_value, lldb::DynamicValueType use_dynamic,
     TypeAndOrName &class_type_or_name, Address &address,
-    Value::ValueType &value_type) {
+    Value::ValueType &value_type, llvm::ArrayRef<uint8_t> &local_buffer) {
   AppleObjCRuntime *objc_runtime =
       SwiftLanguageRuntime::GetObjCRuntime(GetProcess());
   if (!objc_runtime)
@@ -2684,8 +2717,9 @@ bool SwiftLanguageRuntime::GetDynamicTypeAndAddress_ClangType(
   // resolution first, and then map the dynamic Objective-C type back
   // into Swift.
   TypeAndOrName dyn_class_type_or_name = class_type_or_name;
-  if (!objc_runtime->GetDynamicTypeAndAddress(
-          in_value, use_dynamic, dyn_class_type_or_name, address, value_type))
+  if (!objc_runtime->GetDynamicTypeAndAddress(in_value, use_dynamic,
+                                              dyn_class_type_or_name, address,
+                                              value_type, local_buffer))
     return false;
 
   StringRef dyn_name = dyn_class_type_or_name.GetName().GetStringRef();
@@ -2791,7 +2825,7 @@ static bool CouldHaveDynamicValue(ValueObject &in_value) {
 bool SwiftLanguageRuntime::GetDynamicTypeAndAddress(
     ValueObject &in_value, lldb::DynamicValueType use_dynamic,
     TypeAndOrName &class_type_or_name, Address &address,
-    Value::ValueType &value_type) {
+    Value::ValueType &value_type, llvm::ArrayRef<uint8_t> &local_buffer) {
   class_type_or_name.Clear();
   if (use_dynamic == lldb::eNoDynamicValues)
     return false;
@@ -2800,8 +2834,9 @@ bool SwiftLanguageRuntime::GetDynamicTypeAndAddress(
 
   // Try to import a Clang type into Swift.
   if (in_value.GetObjectRuntimeLanguage() == eLanguageTypeObjC)
-    return GetDynamicTypeAndAddress_ClangType(
-        in_value, use_dynamic, class_type_or_name, address, value_type);
+    return GetDynamicTypeAndAddress_ClangType(in_value, use_dynamic,
+                                              class_type_or_name, address,
+                                              value_type, local_buffer);
 
   if (!CouldHaveDynamicValue(in_value))
     return false;
@@ -2817,7 +2852,8 @@ bool SwiftLanguageRuntime::GetDynamicTypeAndAddress(
   // Type kinds with instance metadata don't need generic type resolution.
   if (is_indirect_enum_case)
     success = GetDynamicTypeAndAddress_IndirectEnumCase(
-        in_value, use_dynamic, class_type_or_name, address, static_value_type);
+        in_value, use_dynamic, class_type_or_name, address, static_value_type,
+        local_buffer);
   else if (type_info.AnySet(eTypeIsPack))
     success = GetDynamicTypeAndAddress_Pack(in_value, val_type, use_dynamic,
                                             class_type_or_name, address,
@@ -2826,7 +2862,7 @@ bool SwiftLanguageRuntime::GetDynamicTypeAndAddress(
            type_info.AllSet(eTypeIsBuiltIn | eTypeIsPointer | eTypeHasValue))
     success = GetDynamicTypeAndAddress_Class(in_value, val_type, use_dynamic,
                                              class_type_or_name, address,
-                                             static_value_type);
+                                             static_value_type, local_buffer);
   else if (type_info.AllSet(eTypeIsMetatype | eTypeIsProtocol))
     success = GetDynamicTypeAndAddress_ExistentialMetatype(
         in_value, val_type, use_dynamic, class_type_or_name, address);
@@ -2850,16 +2886,16 @@ bool SwiftLanguageRuntime::GetDynamicTypeAndAddress(
 
     Flags subst_type_info(bound_type.GetTypeInfo());
     if (subst_type_info.AnySet(eTypeIsClass)) {
-      success = GetDynamicTypeAndAddress_Class(in_value, bound_type,
-                                               use_dynamic, class_type_or_name,
-                                               address, static_value_type);
+      success = GetDynamicTypeAndAddress_Class(
+          in_value, bound_type, use_dynamic, class_type_or_name, address,
+          static_value_type, local_buffer);
     } else if (subst_type_info.AnySet(eTypeIsProtocol)) {
       success = GetDynamicTypeAndAddress_Existential(
           in_value, bound_type, use_dynamic, class_type_or_name, address);
     } else {
-      success = GetDynamicTypeAndAddress_Value(in_value, bound_type,
-                                               use_dynamic, class_type_or_name,
-                                               address, static_value_type);
+      success = GetDynamicTypeAndAddress_Value(
+          in_value, bound_type, use_dynamic, class_type_or_name, address,
+          static_value_type, local_buffer);
     }
   }
 
@@ -2869,8 +2905,9 @@ bool SwiftLanguageRuntime::GetDynamicTypeAndAddress(
     if (static_value_type == Value::ValueType::Invalid)
       static_value_type = in_value.GetValue().GetValueType();
 
-    value_type = GetValueType(in_value, class_type_or_name.GetCompilerType(),
-                              static_value_type, is_indirect_enum_case);
+    value_type =
+        GetValueType(in_value, class_type_or_name.GetCompilerType(),
+                     static_value_type, is_indirect_enum_case, local_buffer);
   }
   return success;
 }
diff --git a/lldb/source/ValueObject/ValueObjectDynamicValue.cpp b/lldb/source/ValueObject/ValueObjectDynamicValue.cpp
@@ -172,7 +172,7 @@ bool ValueObjectDynamicValue::UpdateValue() {
       if (runtime)
         found_dynamic_type = runtime->GetDynamicTypeAndAddress(
             *m_parent, m_use_dynamic, class_type_or_name, dynamic_address,
-            value_type);
+            value_type, local_buffer);
     }
 #endif // LLDB_ENABLE_SWIFT
   if (!found_dynamic_type &&
@@ -193,7 +193,7 @@ bool ValueObjectDynamicValue::UpdateValue() {
       // Fallback to the runtime for `known_type`.
       found_dynamic_type = runtime->GetDynamicTypeAndAddress(
           *m_parent, m_use_dynamic, class_type_or_name, dynamic_address,
-          value_type);
+          value_type, local_buffer);
   } else if (!found_dynamic_type) {
     runtime = process->GetLanguageRuntime(lldb::eLanguageTypeC_plus_plus);
     if (runtime)
diff --git a/lldb/test/API/lang/swift/private_discriminator/TestSwiftPrivateDiscriminator.py b/lldb/test/API/lang/swift/private_discriminator/TestSwiftPrivateDiscriminator.py
@@ -27,7 +27,7 @@ def test(self):
         self.expect("expr --bind-generic-types true -- self", error=True, substrs=["Hint"])
         # This should work because expression evaluation automatically falls back
         # to not binding generic parameters.
-        self.expect("expression self", substrs=['Generic', '<T>', 'n', '23'])
+        self.expect("expression self", substrs=['Generic', '<Builder.Private>', 'n', '23'])
 
         process.Continue()
         # This should work.
diff --git a/lldb/test/API/lang/swift/private_generic_type/TestSwiftPrivateGenericType.py b/lldb/test/API/lang/swift/private_generic_type/TestSwiftPrivateGenericType.py
