Revert "[lldb][DWARFASTParserClang] Make C++ method parsing aware of explicit object parameters" (llvm#124100)

Reverts llvm#124096

Broke linux CI:
```
Note: This is test shard 7 of 42.
[==========] Running 1 test from 1 test suite.
[----------] Global test environment set-up.
[----------] 1 test from DWARFASTParserClangTests
[ RUN      ] DWARFASTParserClangTests.TestParseSubroutine_ExplicitObjectParameter
Expected<T> must be checked before access or destruction.
Expected<T> value was in success state. (Note: Expected<T> values in success mode must still be checked prior to being destroyed).
Stack dump without symbol names (ensure you have llvm-symbolizer in your PATH or set the environment var `LLVM_SYMBOLIZER_PATH` to point to it):
0  SymbolFileDWARFTests 0x0000560271ee5ba7
1  SymbolFileDWARFTests 0x0000560271ee3a2c
2  SymbolFileDWARFTests 0x0000560271ee63ea
3  libc.so.6            0x00007f3e54e5b050
4  libc.so.6            0x00007f3e54ea9e2c
5  libc.so.6            0x00007f3e54e5afb2 gsignal + 18
6  libc.so.6            0x00007f3e54e45472 abort + 211
7  SymbolFileDWARFTests 0x0000560271e79d51
8  SymbolFileDWARFTests 0x0000560271e724f7
9  SymbolFileDWARFTests 0x0000560271f39e2c
10 SymbolFileDWARFTests 0x0000560271f3b368
11 SymbolFileDWARFTests 0x0000560271f3c053
12 SymbolFileDWARFTests 0x0000560271f4cf67
13 SymbolFileDWARFTests 0x0000560271f4c18a
14 SymbolFileDWARFTests 0x0000560271f2561c
15 libc.so.6            0x00007f3e54e4624a
16 libc.so.6            0x00007f3e54e46305 __libc_start_main + 133
17 SymbolFileDWARFTests 0x0000560271e65161
```

Author: Michael137

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

@@ -173,9 +173,7 @@ GetCXXObjectParameter(const DWARFDIE &subprogram,
   if (!DeclKindIsCXXClass(containing_decl_ctx.getDeclKind()))
     return {};
 
-  if (DWARFDIE object_parameter =
-          subprogram.GetAttributeValueAsReferenceDIE(DW_AT_object_pointer))
-    return object_parameter;
+  // FIXME: if subprogram has a explicit DW_AT_object_pointer, use it.
 
   // If no DW_AT_object_pointer was specified, assume the implicit object
   // parameter is the first parameter to the function, is called "this" and is
@@ -217,6 +215,11 @@ static unsigned GetCXXMethodCVQuals(const DWARFDIE &subprogram,
     return 0;
 
   uint32_t encoding_mask = this_type->GetEncodingMask();
+
+  // FIXME: explicit object parameters need not to be pointers
+  if (!(encoding_mask & (1u << Type::eEncodingIsPointerUID)))
+    return 0;
+
   unsigned cv_quals = 0;
   if (encoding_mask & (1u << Type::eEncodingIsConstUID))
     cv_quals |= clang::Qualifiers::Const;

lldb/unittests/SymbolFile/DWARF/DWARFASTParserClangTests.cpp

@@ -902,181 +902,3 @@ TEST_F(DWARFASTParserClangTests, TestParseDWARFAttributes_ObjectPointer) {
   EXPECT_TRUE(attrs.object_pointer.IsValid());
   EXPECT_EQ(attrs.object_pointer, param_die);
 }
-
-TEST_F(DWARFASTParserClangTests, TestParseSubroutine_ExplicitObjectParameter) {
-  // Tests parsing of a C++ non-static member function with an explicit object
-  // parameter that isn't called "this" and is not a pointer (but a CV-qualified
-  // rvalue reference instead).
-
-  const char *yamldata = R"(
---- !ELF
-FileHeader:
-  Class:   ELFCLASS64
-  Data:    ELFDATA2LSB
-  Type:    ET_EXEC
-  Machine: EM_AARCH64
-DWARF:
-  debug_str:
-    - Context
-    - func
-    - mySelf
-  debug_abbrev:
-    - ID:              0
-      Table:
-        - Code:            0x1
-          Tag:             DW_TAG_compile_unit
-          Children:        DW_CHILDREN_yes
-          Attributes:
-            - Attribute:       DW_AT_language
-              Form:            DW_FORM_data2
-        - Code:            0x2
-          Tag:             DW_TAG_structure_type
-          Children:        DW_CHILDREN_yes
-          Attributes:
-            - Attribute:       DW_AT_name
-              Form:            DW_FORM_strp
-        - Code:            0x3
-          Tag:             DW_TAG_subprogram
-          Children:        DW_CHILDREN_yes
-          Attributes:
-            - Attribute:       DW_AT_name
-              Form:            DW_FORM_strp
-            - Attribute:       DW_AT_declaration
-              Form:            DW_FORM_flag_present
-            - Attribute:       DW_AT_object_pointer
-              Form:            DW_FORM_ref4
-            - Attribute:       DW_AT_external
-              Form:            DW_FORM_flag_present
-        - Code:            0x4
-          Tag:             DW_TAG_formal_parameter
-          Children:        DW_CHILDREN_no
-          Attributes:
-            - Attribute:       DW_AT_name
-              Form:            DW_FORM_strp
-            - Attribute:       DW_AT_type
-              Form:            DW_FORM_ref4
-        - Code:            0x5
-          Tag:             DW_TAG_rvalue_reference_type
-          Children:        DW_CHILDREN_no
-          Attributes:
-            - Attribute:       DW_AT_type
-              Form:            DW_FORM_ref4
-        - Code:            0x6
-          Tag:             DW_TAG_const_type
-          Children:        DW_CHILDREN_no
-          Attributes:
-            - Attribute:       DW_AT_type
-              Form:            DW_FORM_ref4
-        - Code:            0x7
-          Tag:             DW_TAG_volatile_type
-          Children:        DW_CHILDREN_no
-          Attributes:
-            - Attribute:       DW_AT_type
-              Form:            DW_FORM_ref4
-  debug_info:
-     - Version:         5
-       UnitType:        DW_UT_compile
-       AddrSize:        8
-       Entries:
-
-# DW_TAG_compile_unit
-#   DW_AT_language [DW_FORM_data2]    (DW_LANG_C_plus_plus)
-
-        - AbbrCode:        0x1
-          Values:
-            - Value:           0x04
-
-#   DW_TAG_structure_type
-#     DW_AT_name [DW_FORM_strp] ("Context")
-
-        - AbbrCode:        0x2
-          Values:
-            - Value:           0x0
-
-#     DW_TAG_subprogram
-#       DW_AT_name [DW_FORM_strp] ("func")
-#       DW_AT_object_pointer [DW_FORM_ref4]
-        - AbbrCode:        0x3
-          Values:
-            - Value:           0x8
-            - Value:           0x1
-            - Value:           0x1d
-            - Value:           0x1
-
-#       DW_TAG_formal_parameter
-#         DW_AT_name [DW_FORM_strp] ("mySelf")
-#         DW_AT_type [DW_FORM_ref4] (const volatile Context &&)
-        - AbbrCode:        0x4
-          Values:
-            - Value: 0xd
-            - Value: 0x28
-
-        - AbbrCode: 0x0
-        - AbbrCode: 0x0
-
-#   DW_TAG_rvalue_reference_type
-#     DW_AT_type [DW_FORM_ref4] ("const volatile Context")
-
-        - AbbrCode:        0x5
-          Values:
-            - Value:           0x2d
-
-#   DW_TAG_const_type
-#     DW_AT_type [DW_FORM_ref4] ("volatile Context")
-
-        - AbbrCode:        0x6
-          Values:
-            - Value:           0x32
-
-#   DW_TAG_volatile_type
-#     DW_AT_type [DW_FORM_ref4] ("Context")
-
-        - AbbrCode:        0x7
-          Values:
-            - Value:           0xf
-
-        - AbbrCode: 0x0
-...
-)";
-  YAMLModuleTester t(yamldata);
-
-  DWARFUnit *unit = t.GetDwarfUnit();
-  ASSERT_NE(unit, nullptr);
-  const DWARFDebugInfoEntry *cu_entry = unit->DIE().GetDIE();
-  ASSERT_EQ(cu_entry->Tag(), DW_TAG_compile_unit);
-  ASSERT_EQ(unit->GetDWARFLanguageType(), DW_LANG_C_plus_plus);
-  DWARFDIE cu_die(unit, cu_entry);
-
-  auto ts_or_err =
-      cu_die.GetDWARF()->GetTypeSystemForLanguage(eLanguageTypeC_plus_plus);
-  auto *parser =
-      static_cast<DWARFASTParserClang *>((*ts_or_err)->GetDWARFParser());
-
-  auto context_die = cu_die.GetFirstChild();
-  ASSERT_TRUE(context_die.IsValid());
-  ASSERT_EQ(context_die.Tag(), DW_TAG_structure_type);
-
-  SymbolContext sc;
-  bool new_type;
-  auto context_type_sp = parser->ParseTypeFromDWARF(sc, context_die, &new_type);
-  ASSERT_NE(context_type_sp, nullptr);
-
-  ASSERT_TRUE(
-      parser->CompleteTypeFromDWARF(context_die, context_type_sp.get(),
-                                    context_type_sp->GetForwardCompilerType()));
-
-  auto *record_decl = llvm::dyn_cast_or_null<clang::CXXRecordDecl>(
-      ClangUtil::GetAsTagDecl(context_type_sp->GetForwardCompilerType()));
-  ASSERT_NE(record_decl, nullptr);
-
-  auto method_it = record_decl->method_begin();
-  ASSERT_NE(method_it, record_decl->method_end());
-
-  // Check that we didn't parse the function as static.
-  EXPECT_FALSE(method_it->isStatic());
-
-  // Check that method qualifiers were correctly set.
-  EXPECT_EQ(method_it->getMethodQualifiers(),
-            clang::Qualifiers::fromCVRMask(clang::Qualifiers::Const |
-                                           clang::Qualifiers::Volatile));
-}