[Clang,debuginfo] added vtt parameter in destructor DISubroutineType (#130674)

Fixes issue #104765: When creating a virtual destructor with an
artificial "vtt" argument, the type of "vtt" was previously missing in
the `DISubroutineType` `types` array.

This commit fixes this behavior and adds a regression test.

Author: mgschossmann

clang/lib/CodeGen/CGDebugInfo.cpp

@@ -2018,8 +2018,17 @@ CGDebugInfo::getOrCreateMethodType(const CXXMethodDecl *Method,
   return getOrCreateInstanceMethodType(ThisType, Func, Unit);
 }
 
-llvm::DISubroutineType *CGDebugInfo::getOrCreateInstanceMethodType(
-    QualType ThisPtr, const FunctionProtoType *Func, llvm::DIFile *Unit) {
+llvm::DISubroutineType *CGDebugInfo::getOrCreateMethodTypeForDestructor(
+    const CXXMethodDecl *Method, llvm::DIFile *Unit, QualType FNType) {
+  const FunctionProtoType *Func = FNType->getAs<FunctionProtoType>();
+  // skip the first param since it is also this
+  return getOrCreateInstanceMethodType(Method->getThisType(), Func, Unit, true);
+}
+
+llvm::DISubroutineType *
+CGDebugInfo::getOrCreateInstanceMethodType(QualType ThisPtr,
+                                           const FunctionProtoType *Func,
+                                           llvm::DIFile *Unit, bool SkipFirst) {
   FunctionProtoType::ExtProtoInfo EPI = Func->getExtProtoInfo();
   Qualifiers &Qc = EPI.TypeQuals;
   Qc.removeConst();
@@ -2059,7 +2068,7 @@ llvm::DISubroutineType *CGDebugInfo::getOrCreateInstanceMethodType(
   }
 
   // Copy rest of the arguments.
-  for (unsigned i = 1, e = Args.size(); i != e; ++i)
+  for (unsigned i = (SkipFirst ? 2 : 1), e = Args.size(); i != e; ++i)
     Elts.push_back(Args[i]);
 
   // Attach FlagObjectPointer to the explicit "this" parameter.
@@ -4372,6 +4381,12 @@ llvm::DISubroutineType *CGDebugInfo::getOrCreateFunctionType(const Decl *D,
     // subprogram DIE will miss DW_AT_decl_file and DW_AT_decl_line fields.
     return DBuilder.createSubroutineType(DBuilder.getOrCreateTypeArray({}));
 
+  if (const auto *Method = dyn_cast<CXXDestructorDecl>(D)) {
+    // Read method type from 'FnType' because 'D.getType()' does not cover
+    // implicit arguments for destructors.
+    return getOrCreateMethodTypeForDestructor(Method, F, FnType);
+  }
+
   if (const auto *Method = dyn_cast<CXXMethodDecl>(D))
     return getOrCreateMethodType(Method, F);
 

clang/lib/CodeGen/CGDebugInfo.h

@@ -249,9 +249,14 @@ class CGDebugInfo {
   /// to get a method type which includes \c this pointer.
   llvm::DISubroutineType *getOrCreateMethodType(const CXXMethodDecl *Method,
                                                 llvm::DIFile *F);
+
+  llvm::DISubroutineType *
+  getOrCreateMethodTypeForDestructor(const CXXMethodDecl *Method,
+                                     llvm::DIFile *F, QualType FNType);
+
   llvm::DISubroutineType *
   getOrCreateInstanceMethodType(QualType ThisPtr, const FunctionProtoType *Func,
-                                llvm::DIFile *Unit);
+                                llvm::DIFile *Unit, bool SkipFirst = false);
   llvm::DISubroutineType *
   getOrCreateFunctionType(const Decl *D, QualType FnType, llvm::DIFile *F);
   /// \return debug info descriptor for vtable.

clang/test/CodeGenCXX/debug-info-dtor-implicit-args.cpp

@@ -0,0 +1,24 @@
+// RUN: %clang_cc1 -triple x86_64-none-linux-gnu -emit-llvm -debug-info-kind=limited %s -o - | FileCheck %s
+// RUN: %clang_cc1 -triple x86_64-pc-windows-msvc -emit-llvm -debug-info-kind=limited %s -o - | FileCheck --check-prefix MSVC %s
+
+struct B {
+    virtual ~B() {}
+};
+
+struct A : virtual B {
+};
+
+A a;
+
+
+// CHECK-DAG: !{{[0-9]+}} = !DILocalVariable(name: "vtt", arg: 2, scope: ![[destructor:[0-9]+]], type: ![[vtttype:[0-9]+]], flags: DIFlagArtificial)
+// CHECK-DAG: ![[destructor]] = distinct !DISubprogram(name: "~A", {{.*}}, type: ![[subroutinetype:[0-9]+]]
+// CHECK-DAG: ![[subroutinetype]] = !DISubroutineType(types: ![[types:[0-9]+]])
+// CHECK-DAG: [[types]] = !{null, !{{[0-9]+}}, ![[vtttype]]}
+
+// MSVC-DAG: ![[inttype:[0-9]+]] = !DIBasicType(name: "int", size: 32, encoding: DW_ATE_signed)
+// MSVC-DAG: ![[voidpointertype:[0-9]+]] = !DIDerivedType(tag: DW_TAG_pointer_type, baseType: null, size: 64)
+// MSVC-DAG: ![[destructor:[0-9]+]] = distinct !DISubprogram(name: "~A", linkageName: "??_GA@@UEAAPEAXI@Z", {{.*}}, type: ![[subroutinetype:[0-9]+]]
+// MSVC-DAG: !{{[0-9]+}} = !DILocalVariable(name: "should_call_delete", arg: 2, scope: ![[destructor]], type: ![[inttype]], flags: DIFlagArtificial)
+// MSVC-DAG: ![[subroutinetype]] = !DISubroutineType(types: ![[types:[0-9]+]])
+// MSVC-DAG: [[types]] = !{![[voidpointertype]], !{{[0-9]+}}, ![[inttype]]}