[Lldb-commits] [lldb] [lldb] Fix crash missing MSInheritanceAttr on CXXRecordDecl with DWARF on Windows (PR #112928)

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Stefan =?utf-8?q?Gränitz?= <stefan.graenitz at gmail.com>
Message-ID:
In-Reply-To: <llvm.org/llvm/llvm-project/pull/112928 at github.com>


llvmbot wrote:


<!--LLVM PR SUMMARY COMMENT-->

@llvm/pr-subscribers-lldb

Author: Stefan Gränitz (weliveindetail)

<details>
<summary>Changes</summary>

In the MS ABI, member pointers to `CXXRecordDecl`s must have a `MSInheritanceAttr` in order to be complete. Otherwise we cannot query their size in memory. This patch checks `MemberPointer` types for completeness (eventually looking at the existence of the attribute) to avoid a crash [further down in the clang AST context](https://github.com/llvm/llvm-project/blob/release/19.x/clang/lib/AST/MicrosoftCXXABI.cpp#L282).

---
Full diff: https://github.com/llvm/llvm-project/pull/112928.diff


2 Files Affected:

- (modified) lldb/source/Plugins/TypeSystem/Clang/TypeSystemClang.cpp (+3) 
- (added) lldb/test/Shell/SymbolFile/DWARF/x86/ms-abi.cpp (+45) 


``````````diff
diff --git a/lldb/source/Plugins/TypeSystem/Clang/TypeSystemClang.cpp b/lldb/source/Plugins/TypeSystem/Clang/TypeSystemClang.cpp
index fe0c53a7e9a3ea..a23dce97f3f299 100644
--- a/lldb/source/Plugins/TypeSystem/Clang/TypeSystemClang.cpp
+++ b/lldb/source/Plugins/TypeSystem/Clang/TypeSystemClang.cpp
@@ -2771,6 +2771,9 @@ static bool GetCompleteQualType(clang::ASTContext *ast,
         ast, llvm::cast<clang::AttributedType>(qual_type)->getModifiedType(),
         allow_completion);
 
+  case clang::Type::MemberPointer:
+    return !qual_type.getTypePtr()->isIncompleteType();
+
   default:
     break;
   }
diff --git a/lldb/test/Shell/SymbolFile/DWARF/x86/ms-abi.cpp b/lldb/test/Shell/SymbolFile/DWARF/x86/ms-abi.cpp
new file mode 100644
index 00000000000000..0e51ec99934f4c
--- /dev/null
+++ b/lldb/test/Shell/SymbolFile/DWARF/x86/ms-abi.cpp
@@ -0,0 +1,45 @@
+// REQUIRES: lld
+
+// Check that we don't crash on variables without MSInheritanceAttr
+
+// RUN: %clang -c --target=x86_64-windows-msvc -gdwarf %s -o %t.obj
+// RUN: lld-link /out:%t.exe %t.obj /nodefaultlib /entry:main /debug
+// RUN: %lldb -f %t.exe -b -o "target variable mp1 mp2 mp3 mp4 mp5 mp6 mp7 mp8 mp9"
+
+class SI {
+  int si;
+};
+struct SI2 {
+  int si2;
+};
+class MI : SI, SI2 {
+  int mi;
+};
+class MI2 : MI {
+  int mi2;
+};
+class VI : virtual MI {
+  int vi;
+};
+class VI2 : virtual SI, virtual SI2 {
+  int vi;
+};
+class /* __unspecified_inheritance*/ UI;
+
+typedef void (SI::*SITYPE)();
+typedef void (MI::*MITYPE)();
+typedef void (MI2::*MI2TYPE)();
+typedef void (VI::*VITYPE)();
+typedef void (VI2::*VI2TYPE)();
+typedef void (UI::*UITYPE)();
+SITYPE mp1 = nullptr;
+MITYPE mp2 = nullptr;
+MI2TYPE mp3 = nullptr;
+VITYPE mp4 = nullptr;
+VI2TYPE mp5 = nullptr;
+UITYPE mp6 = nullptr;
+MITYPE *mp7 = nullptr;
+VI2TYPE *mp8 = nullptr;
+int SI::*mp9 = nullptr;
+
+int main() {}

``````````

</details>


https://github.com/llvm/llvm-project/pull/112928