[clang] [clang-cl]: generate debug info when `novtable` is specified (PR #124643)

[via cfe-commits]

https://github.com/Nerixyz updated https://github.com/llvm/llvm-project/pull/124643

>From 1082c242c297ae510d3e5c192f1620dff724cdf6 Mon Sep 17 00:00:00 2001
From: Nerixyz <nerixdev at outlook.de>
Date: Mon, 27 Jan 2025 23:08:05 +0100
Subject: [PATCH] [clang-cl]: generate debug info when `novtable` is specified

---
 clang/lib/CodeGen/CGDebugInfo.cpp                |  2 +-
 clang/test/CodeGenCXX/debug-info-ms-novtable.cpp | 16 ++++++++++++++++
 2 files changed, 17 insertions(+), 1 deletion(-)
 create mode 100644 clang/test/CodeGenCXX/debug-info-ms-novtable.cpp

diff --git a/clang/lib/CodeGen/CGDebugInfo.cpp b/clang/lib/CodeGen/CGDebugInfo.cpp
index 6cbcaf03844102..f0abfaa7324fcd 100644
--- a/clang/lib/CodeGen/CGDebugInfo.cpp
+++ b/clang/lib/CodeGen/CGDebugInfo.cpp
@@ -2815,7 +2815,7 @@ static bool shouldOmitDefinition(llvm::codegenoptions::DebugInfoKind DebugKind,
   // without any dllimport methods can be used in one DLL and constructed in
   // another, but it is the current behavior of LimitedDebugInfo.
   if (CXXDecl->hasDefinition() && CXXDecl->isDynamicClass() &&
-      !isClassOrMethodDLLImport(CXXDecl))
+      !isClassOrMethodDLLImport(CXXDecl) && !CXXDecl->hasAttr<MSNoVTableAttr>())
     return true;
 
   TemplateSpecializationKind Spec = TSK_Undeclared;
diff --git a/clang/test/CodeGenCXX/debug-info-ms-novtable.cpp b/clang/test/CodeGenCXX/debug-info-ms-novtable.cpp
new file mode 100644
index 00000000000000..d8800608f8b87c
--- /dev/null
+++ b/clang/test/CodeGenCXX/debug-info-ms-novtable.cpp
@@ -0,0 +1,16 @@
+// RUN: %clang -g -S -emit-llvm -fms-extensions -fms-compatibility -target x86_64-pc-windows-msvc -o - %s | FileCheck %s
+
+// CHECK-DAG: ![[FOO:[0-9]+]] = distinct !DICompositeType(tag: DW_TAG_class_type, name: "Foo", file: !{{[0-9]+}}, line: {{[0-9]+}}, size: 128, flags: DIFlagTypePassByReference | DIFlagNonTrivial, elements: ![[FOO_ELEMENTS:[0-9]+]], vtableHolder: ![[FOO]], identifier: ".?AVFoo@@")
+// CHECK-DAG: ![[FOO_ELEMENTS]] = !{![[FOO_VTBL_TY:[0-9]+]], ![[FOO_VTBL_MEMBER:[0-9]+]], ![[FOO_MEMBER:[0-9]+]], ![[FOO_DUMMY:[0-9]+]]}
+// CHECK-DAG: ![[FOO_VTBL_TY]] = !DIDerivedType(tag: DW_TAG_pointer_type, name: "__vtbl_ptr_type", baseType: null, size: 64)
+// CHECK-DAG: ![[FOO_VTBL_MEMBER]] = !DIDerivedType(tag: DW_TAG_member, name: "_vptr$Foo", scope: !10, file: !{{[0-9]+}}, baseType: ![[FOO_VTBL_PTR_TY:[0-9]+]], size: 64, flags: DIFlagArtificial)
+// CHECK-DAG: ![[FOO_VTBL_PTR_TY]] = !DIDerivedType(tag: DW_TAG_pointer_type, baseType: ![[FOO_VTBL_TY]], size: 64)
+// CHECK-DAG: ![[FOO_MEMBER]] = !DIDerivedType(tag: DW_TAG_member, name: "member", scope: ![[FOO]], file: !{{[0-9]+}}, line: {{[0-9]+}}, baseType: !{{[0-9]+}}, size: 32, offset: 64)
+// CHECK-DAG: ![[FOO_DUMMY]] = !DISubprogram(name: "dummy", linkageName: "?dummy at Foo@@EEAAXXZ", scope: ![[FOO]], file: !{{[0-9]+}}, line: {{[0-9]+}}, type: !{{[0-9]+}}, scopeLine: {{[0-9]+}}, containingType: ![[FOO]], virtualIndex: 0, flags: DIFlagPrototyped | DIFlagIntroducedVirtual, spFlags: DISPFlagVirtual)
+class __declspec(novtable) Foo {
+    virtual void dummy() noexcept {};
+
+    int member = 1;
+};
+
+void foo(Foo) {}