Revert "[clang][DebugInfo] Emit DW_AT_object_pointer on function declarations with explicit this"

[mgorny]

Reverts #122928

[llvmbot]

@llvm/pr-subscribers-clang
@llvm/pr-subscribers-llvm-ir
@llvm/pr-subscribers-clang-codegen

@llvm/pr-subscribers-debuginfo

Author: Michał Górny (mgorny)

Changes

Reverts llvm/llvm-project#122928

---

Full diff: https://github.com/llvm/llvm-project/pull/123455.diff

6 Files Affected:

• (modified) clang/lib/CodeGen/CGDebugInfo.cpp (+6-15)
• (modified) clang/test/CodeGenCXX/debug-info-object-pointer.cpp (+4-3)
• (modified) llvm/include/llvm-c/DebugInfo.h (+4-7)
• (modified) llvm/include/llvm/IR/DIBuilder.h (+3-3)
• (modified) llvm/lib/IR/DIBuilder.cpp (+2-6)
• (modified) llvm/lib/IR/DebugInfo.cpp (+4-5)

diff --git a/clang/lib/CodeGen/CGDebugInfo.cpp b/clang/lib/CodeGen/CGDebugInfo.cpp
index 6cbcaf03844102..f88f56c98186da 100644
--- a/clang/lib/CodeGen/CGDebugInfo.cpp
+++ b/clang/lib/CodeGen/CGDebugInfo.cpp
@@ -2016,15 +2016,13 @@ llvm::DISubroutineType *CGDebugInfo::getOrCreateInstanceMethodType(
   // First element is always return type. For 'void' functions it is NULL.
   Elts.push_back(Args[0]);
 
-  const bool HasExplicitObjectParameter = ThisPtr.isNull();
-
-  // "this" pointer is always first argument. For explicit "this"
-  // parameters, it will already be in Args[1].
-  if (!HasExplicitObjectParameter) {
+  // "this" pointer is always first argument.
+  // ThisPtr may be null if the member function has an explicit 'this'
+  // parameter.
+  if (!ThisPtr.isNull()) {
     llvm::DIType *ThisPtrType = getOrCreateType(ThisPtr, Unit);
     TypeCache[ThisPtr.getAsOpaquePtr()].reset(ThisPtrType);
-    ThisPtrType =
-        DBuilder.createObjectPointerType(ThisPtrType, /*Implicit=*/true);
+    ThisPtrType = DBuilder.createObjectPointerType(ThisPtrType);
     Elts.push_back(ThisPtrType);
   }
 
@@ -2032,13 +2030,6 @@ llvm::DISubroutineType *CGDebugInfo::getOrCreateInstanceMethodType(
   for (unsigned i = 1, e = Args.size(); i != e; ++i)
     Elts.push_back(Args[i]);
 
-  // Attach FlagObjectPointer to the explicit "this" parameter.
-  if (HasExplicitObjectParameter) {
-    assert(Elts.size() >= 2 && Args.size() >= 2 &&
-           "Expected at least return type and object parameter.");
-    Elts[1] = DBuilder.createObjectPointerType(Args[1], /*Implicit=*/false);
-  }
-
   llvm::DITypeRefArray EltTypeArray = DBuilder.getOrCreateTypeArray(Elts);
 
   return DBuilder.createSubroutineType(EltTypeArray, OriginalFunc->getFlags(),
@@ -5127,7 +5118,7 @@ llvm::DIType *CGDebugInfo::CreateSelfType(const QualType &QualTy,
   llvm::DIType *CachedTy = getTypeOrNull(QualTy);
   if (CachedTy)
     Ty = CachedTy;
-  return DBuilder.createObjectPointerType(Ty, /*Implicit=*/true);
+  return DBuilder.createObjectPointerType(Ty);
 }
 
 void CGDebugInfo::EmitDeclareOfBlockDeclRefVariable(
diff --git a/clang/test/CodeGenCXX/debug-info-object-pointer.cpp b/clang/test/CodeGenCXX/debug-info-object-pointer.cpp
index 49079f59909968..594d4da791ee84 100644
--- a/clang/test/CodeGenCXX/debug-info-object-pointer.cpp
+++ b/clang/test/CodeGenCXX/debug-info-object-pointer.cpp
@@ -5,11 +5,12 @@
 // CHECK: !DIDerivedType(tag: DW_TAG_pointer_type
 // CHECK-SAME:           flags: DIFlagArtificial | DIFlagObjectPointer
 //
+// // FIXME: DIFlagObjectPointer not attached to the explicit object
+// // argument in the subprogram declaration.
 // CHECK: !DISubprogram(name: "explicit_this",
 //                      flags: DIFlagPrototyped
-//
-// CHECK: !DIDerivedType(tag: DW_TAG_rvalue_reference_type
-// CHECK-SAME:           flags: DIFlagObjectPointer)
+// CHECK-NOT: DIFlagObjectPointer
+// CHECK-NOT: DIFlagArtificial
 //
 // CHECK: !DILocalVariable(name: "this", arg: 1
 // CHECK-SAME:             flags: DIFlagArtificial | DIFlagObjectPointer
diff --git a/llvm/include/llvm-c/DebugInfo.h b/llvm/include/llvm-c/DebugInfo.h
index ac7ee5a7cc9a19..07f87d44088e7e 100644
--- a/llvm/include/llvm-c/DebugInfo.h
+++ b/llvm/include/llvm-c/DebugInfo.h
@@ -870,16 +870,13 @@ LLVMDIBuilderCreateObjCProperty(LLVMDIBuilderRef Builder,
                                 LLVMMetadataRef Ty);
 
 /**
- * Create a uniqued DIType* clone with FlagObjectPointer. If \c Implicit
- * is true, then also set FlagArtificial.
+ * Create a uniqued DIType* clone with FlagObjectPointer and FlagArtificial set.
  * \param Builder   The DIBuilder.
  * \param Type      The underlying type to which this pointer points.
- * \param Implicit  Indicates whether this pointer was implicitly generated
- *                  (i.e., not spelled out in source).
  */
-LLVMMetadataRef LLVMDIBuilderCreateObjectPointerType(LLVMDIBuilderRef Builder,
-                                                     LLVMMetadataRef Type,
-                                                     LLVMBool Implicit);
+LLVMMetadataRef
+LLVMDIBuilderCreateObjectPointerType(LLVMDIBuilderRef Builder,
+                                     LLVMMetadataRef Type);
 
 /**
  * Create debugging information entry for a qualified
diff --git a/llvm/include/llvm/IR/DIBuilder.h b/llvm/include/llvm/IR/DIBuilder.h
index 6c479415b9ed27..cb1150c269a1da 100644
--- a/llvm/include/llvm/IR/DIBuilder.h
+++ b/llvm/include/llvm/IR/DIBuilder.h
@@ -662,9 +662,9 @@ namespace llvm {
     /// Create a uniqued clone of \p Ty with FlagArtificial set.
     static DIType *createArtificialType(DIType *Ty);
 
-    /// Create a uniqued clone of \p Ty with FlagObjectPointer set.
-    /// If \p Implicit is true, also set FlagArtificial.
-    static DIType *createObjectPointerType(DIType *Ty, bool Implicit);
+    /// Create a uniqued clone of \p Ty with FlagObjectPointer and
+    /// FlagArtificial set.
+    static DIType *createObjectPointerType(DIType *Ty);
 
     /// Create a permanent forward-declared type.
     DICompositeType *createForwardDecl(unsigned Tag, StringRef Name,
diff --git a/llvm/lib/IR/DIBuilder.cpp b/llvm/lib/IR/DIBuilder.cpp
index d9bd4f11e89a39..b240a2a39de362 100644
--- a/llvm/lib/IR/DIBuilder.cpp
+++ b/llvm/lib/IR/DIBuilder.cpp
@@ -644,15 +644,11 @@ DIType *DIBuilder::createArtificialType(DIType *Ty) {
   return createTypeWithFlags(Ty, DINode::FlagArtificial);
 }
 
-DIType *DIBuilder::createObjectPointerType(DIType *Ty, bool Implicit) {
+DIType *DIBuilder::createObjectPointerType(DIType *Ty) {
   // FIXME: Restrict this to the nodes where it's valid.
   if (Ty->isObjectPointer())
     return Ty;
-  DINode::DIFlags Flags = DINode::FlagObjectPointer;
-
-  if (Implicit)
-    Flags |= DINode::FlagArtificial;
-
+  DINode::DIFlags Flags = DINode::FlagObjectPointer | DINode::FlagArtificial;
   return createTypeWithFlags(Ty, Flags);
 }
 
diff --git a/llvm/lib/IR/DebugInfo.cpp b/llvm/lib/IR/DebugInfo.cpp
index 4ce518009bd3ea..e5b45e0082a823 100644
--- a/llvm/lib/IR/DebugInfo.cpp
+++ b/llvm/lib/IR/DebugInfo.cpp
@@ -1432,11 +1432,10 @@ LLVMDIBuilderCreateObjCProperty(LLVMDIBuilderRef Builder,
                   PropertyAttributes, unwrapDI<DIType>(Ty)));
 }
 
-LLVMMetadataRef LLVMDIBuilderCreateObjectPointerType(LLVMDIBuilderRef Builder,
-                                                     LLVMMetadataRef Type,
-                                                     LLVMBool Implicit) {
-  return wrap(unwrap(Builder)->createObjectPointerType(unwrapDI<DIType>(Type),
-                                                       Implicit));
+LLVMMetadataRef
+LLVMDIBuilderCreateObjectPointerType(LLVMDIBuilderRef Builder,
+                                     LLVMMetadataRef Type) {
+  return wrap(unwrap(Builder)->createObjectPointerType(unwrapDI<DIType>(Type)));
 }
 
 LLVMMetadataRef