Reland "[lldb][DWARF] Remove object_pointer from ParsedDWARFAttributes (llvm#145065)"

This reverts commit 8775119.

This fixes the `TestObjCInBlockVars.py` LLDB API test.

The issue was that `GetCXXObjectParameter` wouldn't deduce the object
parameter of Objective-C method definitions correctly. In DWARF those
don't have a `DW_AT_specification` (so no link back to a DeclContext
that is a class type). The fix is to only check the validity of the
DeclContext DIE *if* no `DW_AT_object_pointer` exists on the DIE. If
`DW_AT_object_pointer` does exist, we should just always use that as the
object_parameter.

Author: Michael137

lldb/source/Plugins/SymbolFile/DWARF/DWARFASTParserClang.cpp

@@ -445,15 +445,6 @@ ParsedDWARFTypeAttributes::ParsedDWARFTypeAttributes(const DWARFDIE &die) {
       name.SetCString(form_value.AsCString());
       break;
 
-    case DW_AT_object_pointer:
-      // GetAttributes follows DW_AT_specification.
-      // DW_TAG_subprogram definitions and declarations may both
-      // have a DW_AT_object_pointer. Don't overwrite the one
-      // we parsed for the definition with the one from the declaration.
-      if (!object_pointer.IsValid())
-        object_pointer = form_value.Reference();
-      break;
-
     case DW_AT_signature:
       signature = form_value;
       break;
@@ -1116,7 +1107,7 @@ bool DWARFASTParserClang::ParseObjCMethod(
 std::pair<bool, TypeSP> DWARFASTParserClang::ParseCXXMethod(
     const DWARFDIE &die, CompilerType clang_type,
     const ParsedDWARFTypeAttributes &attrs, const DWARFDIE &decl_ctx_die,
-    bool is_static, bool &ignore_containing_context) {
+    const DWARFDIE &object_parameter, bool &ignore_containing_context) {
   Log *log = GetLog(DWARFLog::TypeCompletion | DWARFLog::Lookups);
   SymbolFileDWARF *dwarf = die.GetDWARF();
   assert(dwarf);
@@ -1200,6 +1191,9 @@ std::pair<bool, TypeSP> DWARFASTParserClang::ParseCXXMethod(
       TypeSystemClang::GetDeclContextForType(class_opaque_type), die,
       attrs.name.GetCString());
 
+  // In DWARF, a C++ method is static if it has no object parameter child.
+  const bool is_static = !object_parameter.IsValid();
+
   // We have a C++ member function with no children (this pointer!) and clang
   // will get mad if we try and make a function that isn't well formed in the
   // DWARF, so we will just skip it...
@@ -1225,9 +1219,7 @@ std::pair<bool, TypeSP> DWARFASTParserClang::ParseCXXMethod(
     ClangASTMetadata metadata;
     metadata.SetUserID(die.GetID());
 
-    char const *object_pointer_name =
-        attrs.object_pointer ? attrs.object_pointer.GetName() : nullptr;
-    if (object_pointer_name) {
+    if (char const *object_pointer_name = object_parameter.GetName()) {
       metadata.SetObjectPtrName(object_pointer_name);
       LLDB_LOGF(log, "Setting object pointer name: %s on method object %p.\n",
                 object_pointer_name, static_cast<void *>(cxx_method_decl));
@@ -1323,11 +1315,9 @@ DWARFASTParserClang::ParseSubroutine(const DWARFDIE &die,
         type_handled =
             ParseObjCMethod(*objc_method, die, clang_type, attrs, is_variadic);
       } else if (is_cxx_method) {
-        // In DWARF, a C++ method is static if it has no object parameter child.
-        const bool is_static = !object_parameter.IsValid();
         auto [handled, type_sp] =
-            ParseCXXMethod(die, clang_type, attrs, decl_ctx_die, is_static,
-                           ignore_containing_context);
+            ParseCXXMethod(die, clang_type, attrs, decl_ctx_die,
+                           object_parameter, ignore_containing_context);
         if (type_sp)
           return type_sp;
 
@@ -1422,9 +1412,7 @@ DWARFASTParserClang::ParseSubroutine(const DWARFDIE &die,
           ClangASTMetadata metadata;
           metadata.SetUserID(die.GetID());
 
-          char const *object_pointer_name =
-              attrs.object_pointer ? attrs.object_pointer.GetName() : nullptr;
-          if (object_pointer_name) {
+          if (char const *object_pointer_name = object_parameter.GetName()) {
             metadata.SetObjectPtrName(object_pointer_name);
             LLDB_LOGF(log,
                       "Setting object pointer name: %s on function "

lldb/source/Plugins/SymbolFile/DWARF/DWARFASTParserClang.h

@@ -470,7 +470,8 @@ class DWARFASTParserClang : public lldb_private::plugin::dwarf::DWARFASTParser {
   /// \param[in] decl_ctx_die The DIE representing the DeclContext of the C++
   ///                         method being parsed.
   ///
-  /// \param[in] is_static Is true iff we're parsing a static method.
+  /// \param[in] object_parameter The DIE of this subprogram's object parameter.
+  ///                             May be an invalid DIE for C++ static methods.
   ///
   /// \param[out] ignore_containing_context Will get set to true if the caller
   ///             should treat this C++ method as-if it was not a C++ method.
@@ -485,7 +486,8 @@ class DWARFASTParserClang : public lldb_private::plugin::dwarf::DWARFASTParser {
                  lldb_private::CompilerType clang_type,
                  const ParsedDWARFTypeAttributes &attrs,
                  const lldb_private::plugin::dwarf::DWARFDIE &decl_ctx_die,
-                 bool is_static, bool &ignore_containing_context);
+                 const lldb_private::plugin::dwarf::DWARFDIE &object_parameter,
+                 bool &ignore_containing_context);
 
   lldb::TypeSP ParseArrayType(const lldb_private::plugin::dwarf::DWARFDIE &die,
                               const ParsedDWARFTypeAttributes &attrs);
@@ -555,7 +557,6 @@ struct ParsedDWARFTypeAttributes {
   const char *mangled_name = nullptr;
   lldb_private::ConstString name;
   lldb_private::Declaration decl;
-  lldb_private::plugin::dwarf::DWARFDIE object_pointer;
   lldb_private::plugin::dwarf::DWARFFormValue abstract_origin;
   lldb_private::plugin::dwarf::DWARFFormValue containing_type;
   lldb_private::plugin::dwarf::DWARFFormValue signature;