Author: Michael Buch Date: 2024-09-12T08:11:09+01:00 New Revision: f0c6d30a5d80dd42cb298f857987aa2c8f01e63e
URL: https://github.com/llvm/llvm-project/commit/f0c6d30a5d80dd42cb298f857987aa2c8f01e63e DIFF: https://github.com/llvm/llvm-project/commit/f0c6d30a5d80dd42cb298f857987aa2c8f01e63e.diff LOG: [lldb][DWARFASTParserClang][NFC] Factor out unnamed bitfield creation into helper (#108196) This logic will need adjusting soon for https://github.com/llvm/llvm-project/pull/108155 This patch pulls out the logic for detecting/creating unnamed bitfields out of `ParseSingleMember` to make the latter (in my opinion) more readable. Otherwise we have a large number of similarly named variables in scope. Added: Modified: lldb/source/Plugins/SymbolFile/DWARF/DWARFASTParserClang.cpp lldb/source/Plugins/SymbolFile/DWARF/DWARFASTParserClang.h Removed: ################################################################################ diff --git a/lldb/source/Plugins/SymbolFile/DWARF/DWARFASTParserClang.cpp b/lldb/source/Plugins/SymbolFile/DWARF/DWARFASTParserClang.cpp index 4d688f9a1358b2..5b9de6f1566b05 100644 --- a/lldb/source/Plugins/SymbolFile/DWARF/DWARFASTParserClang.cpp +++ b/lldb/source/Plugins/SymbolFile/DWARF/DWARFASTParserClang.cpp @@ -2858,7 +2858,6 @@ void DWARFASTParserClang::ParseSingleMember( } const uint64_t character_width = 8; - const uint64_t word_width = 32; CompilerType member_clang_type = member_type->GetLayoutCompilerType(); const auto accessibility = attrs.accessibility == eAccessNone @@ -2926,40 +2925,9 @@ void DWARFASTParserClang::ParseSingleMember( detect_unnamed_bitfields = die.GetCU()->Supports_unnamed_objc_bitfields(); - if (detect_unnamed_bitfields) { - std::optional<FieldInfo> unnamed_field_info; - uint64_t last_field_end = - last_field_info.bit_offset + last_field_info.bit_size; - - if (!last_field_info.IsBitfield()) { - // The last field was not a bit-field... - // but if it did take up the entire word then we need to extend - // last_field_end so the bit-field does not step into the last - // fields padding. - if (last_field_end != 0 && ((last_field_end % word_width) != 0)) - last_field_end += word_width - (last_field_end % word_width); - } - - if (ShouldCreateUnnamedBitfield(last_field_info, last_field_end, - this_field_info, layout_info)) { - unnamed_field_info = FieldInfo{}; - unnamed_field_info->bit_size = - this_field_info.bit_offset - last_field_end; - unnamed_field_info->bit_offset = last_field_end; - } - - if (unnamed_field_info) { - clang::FieldDecl *unnamed_bitfield_decl = - TypeSystemClang::AddFieldToRecordType( - class_clang_type, llvm::StringRef(), - m_ast.GetBuiltinTypeForEncodingAndBitSize(eEncodingSint, - word_width), - accessibility, unnamed_field_info->bit_size); - - layout_info.field_offsets.insert(std::make_pair( - unnamed_bitfield_decl, unnamed_field_info->bit_offset)); - } - } + if (detect_unnamed_bitfields) + AddUnnamedBitfieldToRecordTypeIfNeeded(layout_info, class_clang_type, + last_field_info, this_field_info); last_field_info = this_field_info; last_field_info.SetIsBitfield(true); @@ -3764,6 +3732,43 @@ bool DWARFASTParserClang::ShouldCreateUnnamedBitfield( return true; } +void DWARFASTParserClang::AddUnnamedBitfieldToRecordTypeIfNeeded( + ClangASTImporter::LayoutInfo &class_layout_info, + const CompilerType &class_clang_type, const FieldInfo &previous_field, + const FieldInfo ¤t_field) { + // TODO: get this value from target + const uint64_t word_width = 32; + uint64_t last_field_end = previous_field.bit_offset + previous_field.bit_size; + + if (!previous_field.IsBitfield()) { + // The last field was not a bit-field... + // but if it did take up the entire word then we need to extend + // last_field_end so the bit-field does not step into the last + // fields padding. + if (last_field_end != 0 && ((last_field_end % word_width) != 0)) + last_field_end += word_width - (last_field_end % word_width); + } + + // Nothing to be done. + if (!ShouldCreateUnnamedBitfield(previous_field, last_field_end, + current_field, class_layout_info)) + return; + + // Place the unnamed bitfield into the gap between the previous field's end + // and the current field's start. + const uint64_t unnamed_bit_size = current_field.bit_offset - last_field_end; + const uint64_t unnamed_bit_offset = last_field_end; + + clang::FieldDecl *unnamed_bitfield_decl = + TypeSystemClang::AddFieldToRecordType( + class_clang_type, llvm::StringRef(), + m_ast.GetBuiltinTypeForEncodingAndBitSize(eEncodingSint, word_width), + lldb::AccessType::eAccessPublic, unnamed_bit_size); + + class_layout_info.field_offsets.insert( + std::make_pair(unnamed_bitfield_decl, unnamed_bit_offset)); +} + void DWARFASTParserClang::ParseRustVariantPart( DWARFDIE &die, const DWARFDIE &parent_die, const CompilerType &class_clang_type, diff --git a/lldb/source/Plugins/SymbolFile/DWARF/DWARFASTParserClang.h b/lldb/source/Plugins/SymbolFile/DWARF/DWARFASTParserClang.h index 2806fbbeb99d24..3809ee912cec6f 100644 --- a/lldb/source/Plugins/SymbolFile/DWARF/DWARFASTParserClang.h +++ b/lldb/source/Plugins/SymbolFile/DWARF/DWARFASTParserClang.h @@ -266,7 +266,7 @@ class DWARFASTParserClang : public lldb_private::plugin::dwarf::DWARFASTParser { FieldInfo() = default; void SetIsBitfield(bool flag) { is_bitfield = flag; } - bool IsBitfield() { return is_bitfield; } + bool IsBitfield() const { return is_bitfield; } void SetIsArtificial(bool flag) { is_artificial = flag; } bool IsArtificial() const { return is_artificial; } @@ -318,6 +318,35 @@ class DWARFASTParserClang : public lldb_private::plugin::dwarf::DWARFASTParser { FieldInfo const &this_field_info, lldb_private::ClangASTImporter::LayoutInfo const &layout_info) const; + /// Tries to detect whether \ref class_clang_type contained an unnamed + /// bit-field between \ref previous_field and \ref current_field, and if + /// so, adds a clang::FieldDecl representing that bit-field to + /// \ref class_clang_type. + /// + /// This is necessary because Clang (and GCC) doesn't emit a DW_TAG_member + /// entry for unnamed bit-fields. So we derive it (with some exceptions), + /// by checking whether there is a gap between where the storage of a + /// DW_TAG_member ended and the subsequent DW_TAG_member began. + /// + /// \param[in,out] layout_info Layout information of all decls parsed by the + /// current parser. Will contain an entry for + /// the unnamed bit-field if this function created + /// one. + /// + /// \param[in] class_clang_type The RecordType to which the unnamed bit-field + /// will be added (if any). + /// + /// \param[in] previous_field FieldInfo of the previous DW_TAG_member + /// we parsed. + /// + /// \param[in] current_field FieldInfo of the current DW_TAG_member + /// being parsed. + /// + void AddUnnamedBitfieldToRecordTypeIfNeeded( + lldb_private::ClangASTImporter::LayoutInfo &class_layout_info, + const lldb_private::CompilerType &class_clang_type, + const FieldInfo &previous_field, const FieldInfo ¤t_field); + /// Parses a DW_TAG_APPLE_property DIE and appends the parsed data to the /// list of delayed Objective-C properties. /// _______________________________________________ lldb-commits mailing list lldb-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/lldb-commits
