[Lldb-commits] [lldb] [LLDB][NativePDB] Set IsDynmaicCXXType metadata for records (PR #155853)

[via lldb-commits]

https://github.com/Nerixyz created https://github.com/llvm/llvm-project/pull/155853

All records were marked as not being a dynamic C++ type - even ones that contain virtual methods. However, these _are_ dynamic C++ types.

With this PR, the metadata for dynamic C++ types is now set when a record is completed and a type is considered dynamic if it has any virtual method (e.g. destructor). 

I'm not sure how to test this. I noticed this when implementing a Microsoft ABI runtime to resolve types based on their vtables (PR TBD).

>From 8505efc3d41de3b12a4ae63a70d50055a02f06fd Mon Sep 17 00:00:00 2001
From: Nerixyz <nerixdev at outlook.de>
Date: Thu, 28 Aug 2025 16:33:57 +0200
Subject: [PATCH] [LLDB][NativePDB] Set IsDynmaicCXXType metadata for records

---
 lldb/source/Plugins/SymbolFile/NativePDB/PdbAstBuilder.cpp | 1 -
 .../Plugins/SymbolFile/NativePDB/UdtRecordCompleter.cpp    | 7 ++++++-
 .../Plugins/SymbolFile/NativePDB/UdtRecordCompleter.h      | 1 +
 3 files changed, 7 insertions(+), 2 deletions(-)

diff --git a/lldb/source/Plugins/SymbolFile/NativePDB/PdbAstBuilder.cpp b/lldb/source/Plugins/SymbolFile/NativePDB/PdbAstBuilder.cpp
index 709281cb32709..d837eee854801 100644
--- a/lldb/source/Plugins/SymbolFile/NativePDB/PdbAstBuilder.cpp
+++ b/lldb/source/Plugins/SymbolFile/NativePDB/PdbAstBuilder.cpp
@@ -615,7 +615,6 @@ clang::QualType PdbAstBuilder::CreateRecordType(PdbTypeSymId id,
 
   ClangASTMetadata metadata;
   metadata.SetUserID(toOpaqueUid(id));
-  metadata.SetIsDynamicCXXType(false);
 
   CompilerType ct = m_clang.CreateRecordType(
       context, OptionalClangModuleID(), access, uname, llvm::to_underlying(ttk),
diff --git a/lldb/source/Plugins/SymbolFile/NativePDB/UdtRecordCompleter.cpp b/lldb/source/Plugins/SymbolFile/NativePDB/UdtRecordCompleter.cpp
index 1c575e90bd72c..1a9d91f6d6467 100644
--- a/lldb/source/Plugins/SymbolFile/NativePDB/UdtRecordCompleter.cpp
+++ b/lldb/source/Plugins/SymbolFile/NativePDB/UdtRecordCompleter.cpp
@@ -110,9 +110,11 @@ void UdtRecordCompleter::AddMethod(llvm::StringRef name, TypeIndex type_idx,
   lldb::AccessType access_type = TranslateMemberAccess(access);
   bool is_artificial = (options & MethodOptions::CompilerGenerated) ==
                        MethodOptions::CompilerGenerated;
+  bool is_virtual = attrs.isVirtual();
+  m_any_virtual_method = m_any_virtual_method || is_virtual;
   m_ast_builder.clang().AddMethodToCXXRecordType(
       derived_opaque_ty, name.data(), /*asm_label=*/{}, method_ct, access_type,
-      attrs.isVirtual(), attrs.isStatic(), false, false, false, is_artificial);
+      is_virtual, attrs.isStatic(), false, false, false, is_artificial);
 
   m_cxx_record_map[derived_opaque_ty].insert({name, method_ct});
 }
@@ -336,6 +338,9 @@ void UdtRecordCompleter::complete() {
   if (auto *record_decl = llvm::dyn_cast<clang::CXXRecordDecl>(&m_tag_decl)) {
     m_ast_builder.GetClangASTImporter().SetRecordLayout(record_decl, m_layout);
   }
+
+  if (auto meta = m_ast_builder.clang().GetMetadata(&m_tag_decl))
+    meta->SetIsDynamicCXXType(m_any_virtual_method);
 }
 
 uint64_t
diff --git a/lldb/source/Plugins/SymbolFile/NativePDB/UdtRecordCompleter.h b/lldb/source/Plugins/SymbolFile/NativePDB/UdtRecordCompleter.h
index e6e91d0f2c3e4..08edcf39c4cd8 100644
--- a/lldb/source/Plugins/SymbolFile/NativePDB/UdtRecordCompleter.h
+++ b/lldb/source/Plugins/SymbolFile/NativePDB/UdtRecordCompleter.h
@@ -59,6 +59,7 @@ class UdtRecordCompleter : public llvm::codeview::TypeVisitorCallbacks {
   llvm::DenseMap<lldb::opaque_compiler_type_t,
                  llvm::SmallSet<std::pair<llvm::StringRef, CompilerType>, 8>>
       &m_cxx_record_map;
+  bool m_any_virtual_method = false;
 
 public:
   UdtRecordCompleter(