[lldb] Make SBType::FindDirectNestedType work with expression ASTs

The types we get out of expressions will not have an associated symbol
file, so the current method of looking up the type will fail. Instead, I
plumb the query through the TypeSystem class. This correctly finds the
type in both cases (importing it into the expression AST if needed). I
haven't measured, but it should also be more efficient than doing a type
lookup (at least, after the type has already been found once).

Author: labath

lldb/include/lldb/Symbol/TypeSystem.h

@@ -28,6 +28,7 @@
 #include "lldb/Symbol/CompilerDeclContext.h"
 #include "lldb/Symbol/Type.h"
 #include "lldb/lldb-private.h"
+#include "lldb/lldb-types.h"
 
 class PDBASTParser;
 
@@ -363,6 +364,12 @@ class TypeSystem : public PluginInterface,
       lldb::opaque_compiler_type_t type, llvm::StringRef name,
       bool omit_empty_base_classes, std::vector<uint32_t> &child_indexes) = 0;
 
+  virtual CompilerType
+  GetDirectNestedTypeWithName(lldb::opaque_compiler_type_t type,
+                              llvm::StringRef name) {
+    return CompilerType();
+  }
+
   virtual bool IsTemplateType(lldb::opaque_compiler_type_t type);
 
   virtual size_t GetNumTemplateArguments(lldb::opaque_compiler_type_t type,

lldb/source/Plugins/TypeSystem/Clang/TypeSystemClang.cpp

@@ -6997,6 +6997,36 @@ TypeSystemClang::GetIndexOfChildWithName(lldb::opaque_compiler_type_t type,
   return UINT32_MAX;
 }
 
+CompilerType
+TypeSystemClang::GetDirectNestedTypeWithName(lldb::opaque_compiler_type_t type,
+                                             llvm::StringRef name) {
+  if (!type || name.empty())
+    return CompilerType();
+
+  clang::QualType qual_type = RemoveWrappingTypes(GetCanonicalQualType(type));
+  const clang::Type::TypeClass type_class = qual_type->getTypeClass();
+
+  switch (type_class) {
+  case clang::Type::Record: {
+    if (!GetCompleteType(type))
+      return CompilerType();
+    const clang::RecordType *record_type =
+        llvm::cast<clang::RecordType>(qual_type.getTypePtr());
+    const clang::RecordDecl *record_decl = record_type->getDecl();
+
+    clang::DeclarationName decl_name(&getASTContext().Idents.get(name));
+    for (NamedDecl *decl : record_decl->lookup(decl_name)) {
+      if (auto *tag_decl = dyn_cast<clang::TagDecl>(decl))
+        return GetType(getASTContext().getTagDeclType(tag_decl));
+    }
+    break;
+  }
+  default:
+    break;
+  }
+  return CompilerType();
+}
+
 bool TypeSystemClang::IsTemplateType(lldb::opaque_compiler_type_t type) {
   if (!type)
     return false;

lldb/source/Plugins/TypeSystem/Clang/TypeSystemClang.h

@@ -897,6 +897,9 @@ class TypeSystemClang : public TypeSystem {
                                 bool omit_empty_base_classes,
                                 std::vector<uint32_t> &child_indexes) override;
 
+  CompilerType GetDirectNestedTypeWithName(lldb::opaque_compiler_type_t type,
+                                           llvm::StringRef name) override;
+
   bool IsTemplateType(lldb::opaque_compiler_type_t type) override;
 
   size_t GetNumTemplateArguments(lldb::opaque_compiler_type_t type,

lldb/source/Symbol/Type.cpp

@@ -1177,20 +1177,8 @@ CompilerType TypeImpl::FindDirectNestedType(llvm::StringRef name) {
   if (name.empty())
     return CompilerType();
   auto type_system = GetTypeSystem(/*prefer_dynamic*/ false);
-  auto *symbol_file = type_system->GetSymbolFile();
-  if (!symbol_file)
-    return CompilerType();
-  auto decl_context = type_system->GetCompilerDeclContextForType(m_static_type);
-  if (!decl_context.IsValid())
-    return CompilerType();
-  TypeQuery query(decl_context, ConstString(name),
-                  TypeQueryOptions::e_find_one);
-  TypeResults results;
-  symbol_file->FindTypes(query, results);
-  TypeSP type_sp = results.GetFirstType();
-  if (type_sp)
-    return type_sp->GetFullCompilerType();
-  return CompilerType();
+  return type_system->GetDirectNestedTypeWithName(
+      m_static_type.GetOpaqueQualType(), name);
 }
 
 bool TypeMemberFunctionImpl::IsValid() {

lldb/test/API/python_api/type/TestTypeList.py

@@ -18,6 +18,21 @@ def setUp(self):
         self.source = "main.cpp"
         self.line = line_number(self.source, "// Break at this line")
 
+    def _find_nested_type_in_Task_pointer(self, pointer_type):
+        self.assertTrue(pointer_type)
+        self.DebugSBType(pointer_type)
+        pointer_info_type = pointer_type.template_args[1]
+        self.assertTrue(pointer_info_type)
+        self.DebugSBType(pointer_info_type)
+
+        pointer_masks1_type = pointer_info_type.FindDirectNestedType("Masks1")
+        self.assertTrue(pointer_masks1_type)
+        self.DebugSBType(pointer_masks1_type)
+
+        pointer_masks2_type = pointer_info_type.FindDirectNestedType("Masks2")
+        self.assertTrue(pointer_masks2_type)
+        self.DebugSBType(pointer_masks2_type)
+
     @skipIf(compiler="clang", compiler_version=["<", "17.0"])
     def test(self):
         """Exercise SBType and SBTypeList API."""
@@ -151,22 +166,12 @@ def test(self):
         invalid_type = task_type.FindDirectNestedType(None)
         self.assertFalse(invalid_type)
 
-        # Check that FindDirectNestedType works with types from AST
-        pointer = frame0.FindVariable("pointer")
-        pointer_type = pointer.GetType()
-        self.assertTrue(pointer_type)
-        self.DebugSBType(pointer_type)
-        pointer_info_type = pointer_type.template_args[1]
-        self.assertTrue(pointer_info_type)
-        self.DebugSBType(pointer_info_type)
-
-        pointer_masks1_type = pointer_info_type.FindDirectNestedType("Masks1")
-        self.assertTrue(pointer_masks1_type)
-        self.DebugSBType(pointer_masks1_type)
-
-        pointer_masks2_type = pointer_info_type.FindDirectNestedType("Masks2")
-        self.assertTrue(pointer_masks2_type)
-        self.DebugSBType(pointer_masks2_type)
+        # Check that FindDirectNestedType works with types from module and
+        # expression ASTs.
+        self._find_nested_type_in_Task_pointer(frame0.FindVariable("pointer").GetType())
+        self._find_nested_type_in_Task_pointer(
+            frame0.EvaluateExpression("pointer").GetType()
+        )
 
         # We'll now get the child member 'id' from 'task_head'.
         id = task_head.GetChildMemberWithName("id")