fixup! fix objective-c case; add unit-test; adjust test docs

Author: Michael137

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

@@ -167,16 +167,17 @@ DWARFASTParserClang::GetObjectParameter(const DWARFDIE &subprogram,
          subprogram.Tag() == DW_TAG_inlined_subroutine ||
          subprogram.Tag() == DW_TAG_subroutine_type);
 
-  if (!decl_ctx_die.IsStructUnionOrClass())
-    return {};
-
   if (DWARFDIE object_parameter =
           subprogram.GetAttributeValueAsReferenceDIE(DW_AT_object_pointer))
     return object_parameter;
 
   // 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
   // artificial (which is what most compilers would generate).
+
+  if (!decl_ctx_die.IsStructUnionOrClass())
+    return {};
+
   auto children = subprogram.children();
   auto it = llvm::find_if(children, [](const DWARFDIE &child) {
     return child.Tag() == DW_TAG_formal_parameter;

lldb/unittests/SymbolFile/DWARF/DWARFASTParserClangTests.cpp

@@ -742,8 +742,8 @@ TEST_F(DWARFASTParserClangTests, TestUniqueDWARFASTTypeMap_CppInsertMapFind) {
   ASSERT_EQ(type_sp, reparsed_type_sp);
 }
 
-TEST_F(DWARFASTParserClangTests, TestParseDWARFAttributes_ObjectPointer) {
-  // This tests the behaviour of ParsedDWARFTypeAttributes
+TEST_F(DWARFASTParserClangTests, TestObjectPointer) {
+  // This tests the behaviour of DWARFASTParserClang
   // for DW_TAG_subprogram definitions which have a DW_AT_object_pointer
   // *and* a DW_AT_specification that also has a DW_AT_object_pointer.
   // We don't want the declaration DW_AT_object_pointer to overwrite the
@@ -916,6 +916,165 @@ TEST_F(DWARFASTParserClangTests, TestParseDWARFAttributes_ObjectPointer) {
   }
 }
 
+TEST_F(DWARFASTParserClangTests,
+       TestObjectPointer_NoSpecificationOnDefinition) {
+  // This tests the behaviour of DWARFASTParserClang
+  // for DW_TAG_subprogram definitions which have a DW_AT_object_pointer
+  // but no DW_AT_specification that would link back to its declaration.
+  // This is how Objective-C class method definitions are emitted.
+
+  const char *yamldata = R"(
+--- !ELF
+FileHeader:
+  Class:   ELFCLASS64
+  Data:    ELFDATA2LSB
+  Type:    ET_EXEC
+  Machine: EM_AARCH64
+DWARF:
+  debug_str:
+    - Context
+    - func
+    - this
+  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_artificial
+              Form:            DW_FORM_flag_present
+            - Attribute:       DW_AT_external
+              Form:            DW_FORM_flag_present
+        - Code:            0x4
+          Tag:             DW_TAG_formal_parameter
+          Children:        DW_CHILDREN_no
+          Attributes:
+            - Attribute:       DW_AT_artificial
+              Form:            DW_FORM_flag_present
+        - Code:            0x5
+          Tag:             DW_TAG_subprogram
+          Children:        DW_CHILDREN_yes
+          Attributes:
+            - Attribute:       DW_AT_object_pointer
+              Form:            DW_FORM_ref4
+        - Code:            0x6
+          Tag:             DW_TAG_formal_parameter
+          Children:        DW_CHILDREN_no
+          Attributes:
+            - Attribute:       DW_AT_name
+              Form:            DW_FORM_strp
+            - Attribute:       DW_AT_artificial
+              Form:            DW_FORM_flag_present
+  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
+            - Value:           0x1
+
+#       DW_TAG_formal_parameter
+#         DW_AT_artificial
+        - AbbrCode:        0x4
+          Values:
+          - Value: 0x1
+
+        - AbbrCode: 0x0
+        - AbbrCode: 0x0
+
+#     DW_TAG_subprogram
+#       DW_AT_object_pointer [DW_FORM_ref4] ("this")
+#       DW_AT_specification [DW_FORM_ref4] ("func")
+        - AbbrCode:        0x5
+          Values:
+            - Value:           0x29
+
+#       DW_TAG_formal_parameter
+#         DW_AT_name [DW_FORM_strp] ("this")
+#         DW_AT_artificial
+        - AbbrCode:        0x6
+          Values:
+            - Value:           0xd
+            - Value:           0x1
+
+        - AbbrCode: 0x0
+        - 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 holder = std::make_unique<clang_utils::TypeSystemClangHolder>("ast");
+  auto &ast_ctx = *holder->GetAST();
+  DWARFASTParserClangStub ast_parser(ast_ctx);
+
+  auto context_die = cu_die.GetFirstChild();
+  ASSERT_TRUE(context_die.IsValid());
+  ASSERT_EQ(context_die.Tag(), DW_TAG_structure_type);
+
+  auto subprogram_definition = context_die.GetSibling();
+  ASSERT_TRUE(subprogram_definition.IsValid());
+  ASSERT_EQ(subprogram_definition.Tag(), DW_TAG_subprogram);
+  ASSERT_FALSE(subprogram_definition.GetAttributeValueAsOptionalUnsigned(
+      DW_AT_external));
+  ASSERT_FALSE(
+      subprogram_definition.GetAttributeValueAsReferenceDIE(DW_AT_specification)
+          .IsValid());
+
+  auto param_die = subprogram_definition.GetFirstChild();
+  ASSERT_TRUE(param_die.IsValid());
+  EXPECT_EQ(param_die,
+            ast_parser.GetObjectParameter(subprogram_definition, {}));
+}
+
 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