[Lldb-commits] [lldb] [lldb] Infer MSInheritanceAttr for CXXRecordDecl with DWARF on Windows (PR #115177)

[Stefan Gränitz via lldb-commits]

https://github.com/weliveindetail created https://github.com/llvm/llvm-project/pull/115177

Following up from https://github.com/llvm/llvm-project/pull/112928, we can reuse the [approach from Clang Sema](https://github.com/llvm/llvm-project/blob/release/19.x/clang/lib/Sema/SemaType.cpp#L9039) to infer the `MSInheritanceModel` and add the necessary attribute manually. This allows the inspection of member function pointers with DWARF on Windows.

>From 32d7b7d5261e651851e5a36c5fd5ae9d927a9fb3 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Stefan=20Gr=C3=A4nitz?= <stefan.graenitz at gmail.com>
Date: Wed, 6 Nov 2024 15:45:03 +0100
Subject: [PATCH] [lldb] Infer MSInheritanceAttr for CXXRecordDecl with DWARF
 on Windows

---
 .../Plugins/SymbolFile/DWARF/DWARFASTParserClang.cpp      | 5 +++++
 lldb/source/Plugins/TypeSystem/Clang/TypeSystemClang.cpp  | 8 +++++++-
 2 files changed, 12 insertions(+), 1 deletion(-)

diff --git a/lldb/source/Plugins/SymbolFile/DWARF/DWARFASTParserClang.cpp b/lldb/source/Plugins/SymbolFile/DWARF/DWARFASTParserClang.cpp
index a30d898a93cc4d..319540389c05ee 100644
--- a/lldb/source/Plugins/SymbolFile/DWARF/DWARFASTParserClang.cpp
+++ b/lldb/source/Plugins/SymbolFile/DWARF/DWARFASTParserClang.cpp
@@ -2138,6 +2138,11 @@ bool DWARFASTParserClang::CompleteRecordType(const DWARFDIE &die,
   if (record_decl)
     GetClangASTImporter().SetRecordLayout(record_decl, layout_info);
 
+  // TODO: Only necessary if we target the Microsoft C++ ABI
+  auto IM = record_decl->calculateInheritanceModel();
+  record_decl->addAttr(clang::MSInheritanceAttr::CreateImplicit(
+      m_ast.getASTContext(), true, {}, clang::MSInheritanceAttr::Spelling(IM)));
+
   // Now parse all contained types inside of the class. We make forward
   // declarations to all classes, but we need the CXXRecordDecl to have decls
   // for all contained types because we don't get asked for them via the
diff --git a/lldb/source/Plugins/TypeSystem/Clang/TypeSystemClang.cpp b/lldb/source/Plugins/TypeSystem/Clang/TypeSystemClang.cpp
index f5063175d6e070..a1e224a395e69f 100644
--- a/lldb/source/Plugins/TypeSystem/Clang/TypeSystemClang.cpp
+++ b/lldb/source/Plugins/TypeSystem/Clang/TypeSystemClang.cpp
@@ -2771,8 +2771,14 @@ static bool GetCompleteQualType(clang::ASTContext *ast,
         ast, llvm::cast<clang::AttributedType>(qual_type)->getModifiedType(),
         allow_completion);
 
-  case clang::Type::MemberPointer:
+  case clang::Type::MemberPointer: {
+    auto *MPT = qual_type.getTypePtr()->castAs<clang::MemberPointerType>();
+    if (MPT->getClass()->isRecordType())
+      GetCompleteRecordType(ast, clang::QualType(MPT->getClass(), 0),
+                            allow_completion);
+
     return !qual_type.getTypePtr()->isIncompleteType();
+  }
 
   default:
     break;