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Differential D150589

[lldb][DWARFASTParserClang][NFC] Simplify unnamed bitfield condition
ClosedPublic

Authored by Michael137 on May 15 2023, 9:50 AM.

Details

Reviewers
aprantl
shafik
Commits
rGca64f9af0447: [lldb][DWARFASTParserClang][NFC] Simplify unnamed bitfield condition
Summary

Minor cleanup of redundant variable initialization and
if-condition. These are leftovers/oversights from previous
cleanup in this area:

Diff Detail

Revision Contents

PathSize
lldb/
source/
Plugins/
SymbolFile/
DWARF/
11 lines

Diff 522519

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

Show First 20 Lines • Show All 2,874 Lines • ▼ Show 20 Lines if (attrs.bit_size > 0) {
bool detect_unnamed_bitfields = true; bool detect_unnamed_bitfields = true;
if (class_is_objc_object_or_interface) if (class_is_objc_object_or_interface)
detect_unnamed_bitfields = detect_unnamed_bitfields =
die.GetCU()->Supports_unnamed_objc_bitfields(); die.GetCU()->Supports_unnamed_objc_bitfields();
if (detect_unnamed_bitfields) { if (detect_unnamed_bitfields) {
std::optional<FieldInfo> unnamed_field_info; std::optional<FieldInfo> unnamed_field_info;
uint64_t last_field_end = 0; uint64_t last_field_end =
last_field_info.bit_offset + last_field_info.bit_size;
last_field_end = last_field_info.bit_offset + last_field_info.bit_size;
if (!last_field_info.IsBitfield()) { if (!last_field_info.IsBitfield()) {
// The last field was not a bit-field... // The last field was not a bit-field...
// but if it did take up the entire word then we need to extend // 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 // last_field_end so the bit-field does not step into the last
// fields padding. // fields padding.
if (last_field_end != 0 && ((last_field_end % word_width) != 0)) if (last_field_end != 0 && ((last_field_end % word_width) != 0))
last_field_end += word_width - (last_field_end % word_width); last_field_end += word_width - (last_field_end % word_width);
} }
// If we have a gap between the last_field_end and the current // If we have a gap between the last_field_end and the current
// field we have an unnamed bit-field. // field we have an unnamed bit-field.
// If we have a base class, we assume there is no unnamed // If we have a base class, we assume there is no unnamed
// bit-field if this is the first field since the gap can be // bit-field if this is the first field since the gap can be
// attributed to the members from the base class. This assumption // attributed to the members from the base class. This assumption
// is not correct if the first field of the derived class is // is not correct if the first field of the derived class is
// indeed an unnamed bit-field. We currently do not have the // indeed an unnamed bit-field. We currently do not have the
// machinary to track the offset of the last field of classes we // machinary to track the offset of the last field of classes we
// have seen before, so we are not handling this case. // have seen before, so we are not handling this case.
if (this_field_info.bit_offset != last_field_end && if (this_field_info.bit_offset > last_field_end &&
this_field_info.bit_offset > last_field_end && !(last_field_info.bit_offset == 0 && last_field_info.bit_size == 0 &&
!(last_field_info.bit_offset == 0 &&
last_field_info.bit_size == 0 &&
layout_info.base_offsets.size() != 0)) { layout_info.base_offsets.size() != 0)) {
unnamed_field_info = FieldInfo{}; unnamed_field_info = FieldInfo{};
unnamed_field_info->bit_size = unnamed_field_info->bit_size =
this_field_info.bit_offset - last_field_end; this_field_info.bit_offset - last_field_end;
unnamed_field_info->bit_offset = last_field_end; unnamed_field_info->bit_offset = last_field_end;
} }
if (unnamed_field_info) { if (unnamed_field_info) {
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