Handle virtual destructors in C++ classes

This resolves crashing on virtual destructors if Clang is build with
assertions and corrects vtbl indices for tables with destructors.

Fixes #240.

Author: zeule

sources/ClangSharp.Interop/CX_DestructorType.cs

@@ -0,0 +1,13 @@
+// Copyright (c) Microsoft and Contributors. All rights reserved. Licensed under the University of Illinois/NCSA Open Source License. See LICENSE.txt in the project root for license information.
+// Ported from https://github.com/microsoft/ClangSharp/blob/main/sources/libClangSharp
+
+namespace ClangSharp.Interop
+{
+    public enum CX_DestructorType
+    {
+        Deleting,
+        Complete,
+        Base,
+        Comdat
+    }
+}

sources/ClangSharp.Interop/clangsharp.cs

@@ -865,6 +865,10 @@ public static partial class clangsharp
         [DllImport("libClangSharp", CallingConvention = CallingConvention.Cdecl, EntryPoint = "clangsharp_Cursor_getVBase", ExactSpelling = true)]
         public static extern CXCursor Cursor_getVBase(CXCursor C, [NativeTypeName("unsigned int")] uint i);
 
+        [DllImport("libClangSharp", CallingConvention = CallingConvention.Cdecl, EntryPoint = "clangsharp_Cursor_getDtorVtblIdx", ExactSpelling = true)]
+        [return: NativeTypeName("int64_t")]
+        public static extern long Cursor_getDtorVtblIdx(CXCursor C, CX_DestructorType dtor);
+
         [DllImport("libClangSharp", CallingConvention = CallingConvention.Cdecl, EntryPoint = "clangsharp_Cursor_getVtblIdx", ExactSpelling = true)]
         [return: NativeTypeName("int64_t")]
         public static extern long Cursor_getVtblIdx(CXCursor C);

sources/libClangSharp/ClangSharp.cpp

@@ -8,12 +8,16 @@
 #include "CXTranslationUnit.h"
 #include "CXType.h"
 
+#ifdef _MSC_VER
 #pragma warning(push)
 #pragma warning(disable : 4146 4244 4267 4291 4624 4996)
+#endif
 
 #include <clang/Basic/SourceManager.h>
 
+#ifdef _MSC_VER
 #pragma warning(pop)
+#endif
 
 using namespace clang;
 using namespace clang::cxcursor;
@@ -61,6 +65,25 @@ bool isStmtOrExpr(CXCursorKind kind) {
     return clang_isStatement(kind) || clang_isExpression(kind);
 }
 
+int64_t getVtblIdx(const GlobalDecl& d)
+{
+    const CXXMethodDecl* CMD = static_cast<const CXXMethodDecl*>(d.getDecl());
+    if (VTableContextBase::hasVtableSlot(CMD)) {
+        VTableContextBase* VTC = CMD->getASTContext().getVTableContext();
+
+        if (MicrosoftVTableContext* MSVTC = dyn_cast<MicrosoftVTableContext>(VTC)) {
+            MethodVFTableLocation ML = MSVTC->getMethodVFTableLocation(d);
+            return ML.Index;
+        }
+
+        if (ItaniumVTableContext* IVTC = dyn_cast<ItaniumVTableContext>(VTC)) {
+            return IVTC->getMethodVTableIndex(d);
+        }
+    }
+
+    return -1;
+}
+
 CXCursor clangsharp_Cursor_getArgument(CXCursor C, unsigned i) {
     if (isDeclOrTU(C.kind)) {
         const Decl* D = getCursorDecl(C);
@@ -4693,23 +4716,30 @@ CXCursor clangsharp_Cursor_getVBase(CXCursor C, unsigned i) {
     return clang_getNullCursor();
 }
 
-int64_t clangsharp_Cursor_getVtblIdx(CXCursor C) {
+int64_t clangsharp_Cursor_getDtorVtblIdx(CXCursor C, CX_DestructorType dtor)
+{
     if (isDeclOrTU(C.kind)) {
         const Decl* D = getCursorDecl(C);
 
-        if (const CXXMethodDecl* CMD = dyn_cast<CXXMethodDecl>(D)) {
-            if (VTableContextBase::hasVtableSlot(CMD)) {
-                VTableContextBase* VTC = getASTUnit(getCursorTU(C))->getASTContext().getVTableContext();
+        if (const CXXDestructorDecl* CMD = dyn_cast<CXXDestructorDecl>(D)) {
+            return getVtblIdx(GlobalDecl(CMD, static_cast<CXXDtorType>(dtor)));
+        }
+    }
+    return -1;
+}
 
-                if (MicrosoftVTableContext* MSVTC = dyn_cast<MicrosoftVTableContext>(VTC)) {
-                    MethodVFTableLocation ML = MSVTC->getMethodVFTableLocation(CMD);
-                    return ML.Index;
-                }
+int64_t clangsharp_Cursor_getVtblIdx(CXCursor C) {
+    if (isDeclOrTU(C.kind)) {
+        const Decl* D = getCursorDecl(C);
 
-                if (ItaniumVTableContext* IVTC = dyn_cast<ItaniumVTableContext>(VTC)) {
-                    return IVTC->getMethodVTableIndex(CMD);
-                }
+        if (const CXXMethodDecl* CMD = dyn_cast<CXXMethodDecl>(D)) {
+            int64_t dtorIdx = clangsharp_Cursor_getDtorVtblIdx(C, Deleting); // will test if CMD is a dtor
+            if (dtorIdx != -1) { // yes, it is a dtor
+                return dtorIdx;
             }
+
+            // no, it is a regular method
+            return getVtblIdx(CMD);
         }
     }
 

sources/libClangSharp/ClangSharp.h

@@ -3,8 +3,10 @@
 #ifndef LIBCLANGSHARP_CLANGSHARP_H
 #define LIBCLANGSHARP_CLANGSHARP_H
 
+#ifdef _MSC_VER
 #pragma warning(push)
 #pragma warning(disable : 4146 4244 4267 4291 4624 4996)
+#endif
 
 #include <clang/AST/Decl.h>
 #include <clang/AST/DeclCXX.h>
@@ -19,7 +21,9 @@
 #include <clang/Basic/Specifiers.h>
 #include <clang-c/Index.h>
 
+#ifdef _MSC_VER
 #pragma warning(pop)
+#endif
 
 #ifdef __cplusplus
 #define EXTERN_C extern "C"
@@ -202,6 +206,13 @@ enum CX_VariableCaptureKind {
     CX_VCK_VLAType = clang::CapturedStmt::VCK_VLAType + 1
 };
 
+enum CX_DestructorType {
+    Deleting = clang::Dtor_Deleting,
+    Complete = clang::Dtor_Complete,
+    Base = clang::Dtor_Base,
+    Comdat = clang::Dtor_Comdat
+};
+
 struct CX_TemplateArgument {
     CXTemplateArgumentKind kind;
     int xdata;
@@ -722,6 +733,8 @@ CLANGSHARP_LINKAGE CXCursor clangsharp_Cursor_getUsedContext(CXCursor C);
 
 CLANGSHARP_LINKAGE CXCursor clangsharp_Cursor_getVBase(CXCursor C, unsigned i);
 
+CLANGSHARP_LINKAGE int64_t clangsharp_Cursor_getDtorVtblIdx(CXCursor C, CX_DestructorType dtor);
+
 CLANGSHARP_LINKAGE int64_t clangsharp_Cursor_getVtblIdx(CXCursor C);
 
 CLANGSHARP_LINKAGE void clangsharp_TemplateArgument_dispose(CX_TemplateArgument T);