https://github.com/zyn-li updated https://github.com/llvm/llvm-project/pull/187598
>From f485a14761d0d967c12ff6d17edc458afa7a4f74 Mon Sep 17 00:00:00 2001 From: Zhiyuan Li <[email protected]> Date: Fri, 13 Mar 2026 18:05:10 -0700 Subject: [PATCH] [lldb][DWARFASTParserClang] Handle pointer-to-member-data non-type template parameters --- .../SymbolFile/DWARF/DWARFASTParserClang.cpp | 95 +++++++++++++++++-- .../SymbolFile/DWARF/DWARFASTParserClang.h | 7 ++ .../Makefile | 3 + .../TestCppNonTypeTemplateParamPtrToMember.py | 15 +++ .../main.cpp | 16 ++++ 5 files changed, 130 insertions(+), 6 deletions(-) create mode 100644 lldb/test/API/lang/cpp/non-type-template-param-member-ptr/Makefile create mode 100644 lldb/test/API/lang/cpp/non-type-template-param-member-ptr/TestCppNonTypeTemplateParamPtrToMember.py create mode 100644 lldb/test/API/lang/cpp/non-type-template-param-member-ptr/main.cpp diff --git a/lldb/source/Plugins/SymbolFile/DWARF/DWARFASTParserClang.cpp b/lldb/source/Plugins/SymbolFile/DWARF/DWARFASTParserClang.cpp index cb33fc21bfba9..1b5da0d6f8b22 100644 --- a/lldb/source/Plugins/SymbolFile/DWARF/DWARFASTParserClang.cpp +++ b/lldb/source/Plugins/SymbolFile/DWARF/DWARFASTParserClang.cpp @@ -2015,21 +2015,91 @@ static std::optional<clang::APValue> MakeAPValue(const clang::ASTContext &ast, return std::nullopt; bool is_signed = false; - const bool is_integral = clang_type.IsIntegerOrEnumerationType(is_signed); llvm::APSInt apint(*bit_width, !is_signed); apint = value; - if (is_integral) + if (clang_type.IsIntegerOrEnumerationType(is_signed) || + clang_type.IsMemberDataPointerType()) return clang::APValue(apint); // FIXME: we currently support a limited set of floating point types. // E.g., 16-bit floats are not supported. - if (!clang_type.IsRealFloatingPointType()) - return std::nullopt; + if (clang_type.IsRealFloatingPointType()) { + return clang::APValue(llvm::APFloat( + ast.getFloatTypeSemantics(ClangUtil::GetQualType(clang_type)), apint)); + } + + LLDB_LOG(GetLog(LLDBLog::Types), + "MakeAPValue: Unsupported NTTP type class: {0}", + clang_type.GetTypeClass()); + + lldbassert(false && "Unsupported type for non-type template parameter"); + + return std::nullopt; +} + +clang::FieldDecl *DWARFASTParserClang::ResolveMemberDataPointerToFieldDecl( + const DWARFDIE &die, uint64_t member_byte_offset) { + Log *log = GetLog(DWARFLog::TypeCompletion); + + DWARFDIE type_die = die.GetReferencedDIE(DW_AT_type); + if (!type_die || type_die.Tag() != DW_TAG_ptr_to_member_type) { + LLDB_LOG(log, + "ResolveMemberDataPointerToFieldDecl: DIE {0:x16} — " + "expected DW_AT_type to reference a DW_TAG_ptr_to_member_type, " + "got {1}", + die.GetOffset(), + type_die ? llvm::dwarf::TagString(type_die.Tag()) : "null"); + return nullptr; + } + + DWARFDIE containing_die = type_die.GetReferencedDIE(DW_AT_containing_type); + if (!containing_die) { + LLDB_LOG(log, + "ResolveMemberDataPointerToFieldDecl: DIE {0:x16} — " + "DW_TAG_ptr_to_member_type {1:x16} has no DW_AT_containing_type", + die.GetOffset(), type_die.GetOffset()); + return nullptr; + } - return clang::APValue(llvm::APFloat( - ast.getFloatTypeSemantics(ClangUtil::GetQualType(clang_type)), apint)); + Type *containing_type = die.ResolveTypeUID(containing_die); + if (!containing_type) { + LLDB_LOG(log, + "ResolveMemberDataPointerToFieldDecl: DIE {0:x16} — " + "failed to resolve containing type {1:x16}", + die.GetOffset(), containing_die.GetOffset()); + return nullptr; + } + + CompilerType containing_ct = containing_type->GetFullCompilerType(); + auto *record_decl = + m_ast.GetAsCXXRecordDecl(containing_ct.GetOpaqueQualType()); + if (!record_decl) { + LLDB_LOG(log, + "ResolveMemberDataPointerToFieldDecl: DIE {0:x16} — " + "containing type {1:x16} is not a CXXRecordDecl", + die.GetOffset(), containing_die.GetOffset()); + return nullptr; + } + + clang::ASTContext &ast = m_ast.getASTContext(); + for (auto *field : record_decl->fields()) { + if (ast.getFieldOffset(field) / 8 == member_byte_offset) { + LLDB_LOG(log, + "ResolveMemberDataPointerToFieldDecl: DIE {0:x16} — " + "resolved to field '{1}' at byte offset {2} in {3}", + die.GetOffset(), field->getName(), member_byte_offset, + containing_die.GetName()); + return field; + } + } + + LLDB_LOG(log, + "ResolveMemberDataPointerToFieldDecl: DIE {0:x16} — " + "no field found at byte offset {1} in {2}", + die.GetOffset(), member_byte_offset, containing_die.GetName()); + return nullptr; } bool DWARFASTParserClang::ParseTemplateDIE( @@ -2115,6 +2185,19 @@ bool DWARFASTParserClang::ParseTemplateDIE( if (tag == DW_TAG_template_value_parameter && uval64_valid) { if (auto value = MakeAPValue(ast, clang_type, uval64)) { + // For pointer-to-member types, try to resolve to the actual FieldDecl + if (clang_type.IsMemberDataPointerType()) { + if (auto *field = + ResolveMemberDataPointerToFieldDecl(die, uval64)) { + template_param_infos.InsertArg( + name, clang::TemplateArgument( + field, ClangUtil::GetQualType(clang_type), + is_default_template_arg)); + return true; + } + // Failed to resolve FieldDecl, fall through to integer path + } + template_param_infos.InsertArg( name, clang::TemplateArgument( ast, ClangUtil::GetQualType(clang_type), diff --git a/lldb/source/Plugins/SymbolFile/DWARF/DWARFASTParserClang.h b/lldb/source/Plugins/SymbolFile/DWARF/DWARFASTParserClang.h index 03c431c73fb6f..ca76bcdc4ace2 100644 --- a/lldb/source/Plugins/SymbolFile/DWARF/DWARFASTParserClang.h +++ b/lldb/source/Plugins/SymbolFile/DWARF/DWARFASTParserClang.h @@ -185,6 +185,13 @@ class DWARFASTParserClang : public lldb_private::plugin::dwarf::DWARFASTParser { lldb_private::TypeSystemClang::TemplateParameterInfos &template_param_infos); + /// Given a DW_TAG_template_value_parameter DIE whose type is a + /// pointer-to-data-member, follow the DWARF chain to find the FieldDecl + /// at the given byte offset within the containing class. + clang::FieldDecl *ResolveMemberDataPointerToFieldDecl( + const lldb_private::plugin::dwarf::DWARFDIE &die, + uint64_t member_byte_offset); + bool ParseTemplateParameterInfos( const lldb_private::plugin::dwarf::DWARFDIE &parent_die, lldb_private::TypeSystemClang::TemplateParameterInfos diff --git a/lldb/test/API/lang/cpp/non-type-template-param-member-ptr/Makefile b/lldb/test/API/lang/cpp/non-type-template-param-member-ptr/Makefile new file mode 100644 index 0000000000000..99998b20bcb05 --- /dev/null +++ b/lldb/test/API/lang/cpp/non-type-template-param-member-ptr/Makefile @@ -0,0 +1,3 @@ +CXX_SOURCES := main.cpp + +include Makefile.rules diff --git a/lldb/test/API/lang/cpp/non-type-template-param-member-ptr/TestCppNonTypeTemplateParamPtrToMember.py b/lldb/test/API/lang/cpp/non-type-template-param-member-ptr/TestCppNonTypeTemplateParamPtrToMember.py new file mode 100644 index 0000000000000..e8ce16a6c5f9a --- /dev/null +++ b/lldb/test/API/lang/cpp/non-type-template-param-member-ptr/TestCppNonTypeTemplateParamPtrToMember.py @@ -0,0 +1,15 @@ +import lldb +from lldbsuite.test.decorators import * +from lldbsuite.test.lldbtest import * +from lldbsuite.test import lldbutil + + +class TestCase(TestBase): + + def test_member_data_pointer(self): + """Member data pointer NTTPs: MemberData<&S::x> vs MemberData<&S::y>""" + self.build() + self.dbg.CreateTarget(self.getBuildArtifact("a.out")) + # Both must be resolvable as distinct specializations. + self.expect_expr("md1", result_type="MemberData<&S::x>") + self.expect_expr("md2", result_type="MemberData<&S::y>") diff --git a/lldb/test/API/lang/cpp/non-type-template-param-member-ptr/main.cpp b/lldb/test/API/lang/cpp/non-type-template-param-member-ptr/main.cpp new file mode 100644 index 0000000000000..3de9c024c82f9 --- /dev/null +++ b/lldb/test/API/lang/cpp/non-type-template-param-member-ptr/main.cpp @@ -0,0 +1,16 @@ +struct S { + int x; + int y; +}; + +// --- Member data pointer NTTP --- +template <int S::*P> struct MemberData { + int get(S &s) { return s.*P; } +}; +MemberData<&S::x> md1; +MemberData<&S::y> md2; + +int main() { + S s{1, 2}; + return md1.get(s) + md2.get(s); +} _______________________________________________ lldb-commits mailing list [email protected] https://lists.llvm.org/cgi-bin/mailman/listinfo/lldb-commits
