Author: Michael Buch Date: 2025-01-17T14:11:05Z New Revision: dc1ef2cc1aa2de7ef6830419de37ad93eb74d34a
URL: https://github.com/llvm/llvm-project/commit/dc1ef2cc1aa2de7ef6830419de37ad93eb74d34a DIFF: https://github.com/llvm/llvm-project/commit/dc1ef2cc1aa2de7ef6830419de37ad93eb74d34a.diff LOG: [lldb][DWARFASTParserClang] Don't overwrite DW_AT_object_pointer of definition with that of a declaration (#123089) In https://github.com/llvm/llvm-project/pull/122742 we will start attaching DW_AT_object_pointer to method declarations (in addition to definitions). Currently when LLDB parses a `DW_TAG_subprogram` definition, it will parse all the attributes of the declaration as well. If we have `DW_AT_object_pointer` on both, then we would overwrite the more specific attribute that we got from the defintion with the one from the specification. This is problematic because LLDB relies on getting the `DW_AT_name` from the `DW_AT_object_pointer`, which doesn't exist on the specification. Note GCC does attach `DW_AT_object_pointer` on declarations *and* definitions already (see https://godbolt.org/z/G1GvddY48), so there's definitely some expressions that will fail for GCC compiled binaries. This patch will fix those cases (e.g., I would expect `TestConstThis.py` to fail with GCC). Added: Modified: lldb/source/Plugins/SymbolFile/DWARF/DWARFASTParserClang.cpp lldb/unittests/SymbolFile/DWARF/DWARFASTParserClangTests.cpp Removed: ################################################################################ diff --git a/lldb/source/Plugins/SymbolFile/DWARF/DWARFASTParserClang.cpp b/lldb/source/Plugins/SymbolFile/DWARF/DWARFASTParserClang.cpp index e2f76e88dd6f0f..fb3af44abfa8d4 100644 --- a/lldb/source/Plugins/SymbolFile/DWARF/DWARFASTParserClang.cpp +++ b/lldb/source/Plugins/SymbolFile/DWARF/DWARFASTParserClang.cpp @@ -377,7 +377,12 @@ ParsedDWARFTypeAttributes::ParsedDWARFTypeAttributes(const DWARFDIE &die) { break; case DW_AT_object_pointer: - object_pointer = form_value.Reference(); + // 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: diff --git a/lldb/unittests/SymbolFile/DWARF/DWARFASTParserClangTests.cpp b/lldb/unittests/SymbolFile/DWARF/DWARFASTParserClangTests.cpp index f22d76b3973e5f..b31f56aa372d58 100644 --- a/lldb/unittests/SymbolFile/DWARF/DWARFASTParserClangTests.cpp +++ b/lldb/unittests/SymbolFile/DWARF/DWARFASTParserClangTests.cpp @@ -741,3 +741,164 @@ TEST_F(DWARFASTParserClangTests, TestUniqueDWARFASTTypeMap_CppInsertMapFind) { ASSERT_EQ(type_sp, reparsed_type_sp); } + +TEST_F(DWARFASTParserClangTests, TestParseDWARFAttributes_ObjectPointer) { + // This tests the behaviour of ParsedDWARFTypeAttributes + // 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 + // one from the more specific definition's. + + 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 + - Attribute: DW_AT_specification + 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 + - Value: 0x14 + +# 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)); + + auto param_die = subprogram_definition.GetFirstChild(); + ASSERT_TRUE(param_die.IsValid()); + + ParsedDWARFTypeAttributes attrs(subprogram_definition); + EXPECT_TRUE(attrs.object_pointer.IsValid()); + EXPECT_EQ(attrs.object_pointer, param_die); +} _______________________________________________ lldb-commits mailing list lldb-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/lldb-commits
