[Lldb-commits] [lldb] Reland "[lldb][DWARF] Remove object_pointer from ParsedDWARFAttributes (#145065)" (PR #145126)
Michael Buch via lldb-commits
lldb-commits at lists.llvm.org
Sun Jun 22 03:55:45 PDT 2025
https://github.com/Michael137 updated https://github.com/llvm/llvm-project/pull/145126
>From 2572a2f224d8c3372fadc0edfa2af5f618765669 Mon Sep 17 00:00:00 2001
From: Michael Buch <michaelbuch12 at gmail.com>
Date: Fri, 20 Jun 2025 18:09:54 +0100
Subject: [PATCH 1/2] Reland "[lldb][DWARF] Remove object_pointer from
ParsedDWARFAttributes (#145065)"
This reverts commit 877511920dcf36463e06746d626e8876583a6abd.
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.
---
.../SymbolFile/DWARF/DWARFASTParserClang.cpp | 28 ++++++-------------
.../SymbolFile/DWARF/DWARFASTParserClang.h | 7 +++--
2 files changed, 12 insertions(+), 23 deletions(-)
diff --git a/lldb/source/Plugins/SymbolFile/DWARF/DWARFASTParserClang.cpp b/lldb/source/Plugins/SymbolFile/DWARF/DWARFASTParserClang.cpp
index 4f79c8aa3f811..3bec89cdf7469 100644
--- a/lldb/source/Plugins/SymbolFile/DWARF/DWARFASTParserClang.cpp
+++ b/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 "
diff --git a/lldb/source/Plugins/SymbolFile/DWARF/DWARFASTParserClang.h b/lldb/source/Plugins/SymbolFile/DWARF/DWARFASTParserClang.h
index 111604ce4068a..a90f55bcff948 100644
--- a/lldb/source/Plugins/SymbolFile/DWARF/DWARFASTParserClang.h
+++ b/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;
>From cd5412d1bc9d9ef11d4a81268b275052bcd4a0ec Mon Sep 17 00:00:00 2001
From: Michael Buch <michaelbuch12 at gmail.com>
Date: Fri, 20 Jun 2025 18:09:54 +0100
Subject: [PATCH 2/2] fixup! fix objective-c case; add unit-test; adjust test
docs
---
.../SymbolFile/DWARF/DWARFASTParserClang.cpp | 7 +-
.../DWARF/DWARFASTParserClangTests.cpp | 163 +++++++++++++++++-
2 files changed, 165 insertions(+), 5 deletions(-)
diff --git a/lldb/source/Plugins/SymbolFile/DWARF/DWARFASTParserClang.cpp b/lldb/source/Plugins/SymbolFile/DWARF/DWARFASTParserClang.cpp
index e4ecb82c5f1e1..d3912ad55a235 100644
--- a/lldb/source/Plugins/SymbolFile/DWARF/DWARFASTParserClang.cpp
+++ b/lldb/source/Plugins/SymbolFile/DWARF/DWARFASTParserClang.cpp
@@ -167,9 +167,6 @@ 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;
@@ -177,6 +174,10 @@ DWARFASTParserClang::GetObjectParameter(const DWARFDIE &subprogram,
// 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;
diff --git a/lldb/unittests/SymbolFile/DWARF/DWARFASTParserClangTests.cpp b/lldb/unittests/SymbolFile/DWARF/DWARFASTParserClangTests.cpp
index f18e938dbc4c9..0c647ce5adc52 100644
--- a/lldb/unittests/SymbolFile/DWARF/DWARFASTParserClangTests.cpp
+++ b/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
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