+static uint32_t getCUAbbrev(StringRef Abbrev, uint64_t AbbrCode) {
+ uint64_t CurCode;
+ uint32_t Offset = 0;
+ DataExtractor AbbrevData(Abbrev, true, 0);
+ while ((CurCode = AbbrevData.getULEB128(&Offset)) != AbbrCode) {
+ // Tag
+ AbbrevData.getULEB128(&Offset);
+ // DW_CHILDREN
+ AbbrevData.getU8(&Offset);
+ // Attributes
+ while (AbbrevData.getULEB128(&Offset) | AbbrevData.getULEB128(&Offset))
+ ;
+ }
+ return Offset;
+}
+
+static uint64_t getCUSignature(StringRef Abbrev, StringRef Info) {
+ uint32_t Offset = 0;
+ DataExtractor InfoData(Info, true, 0);
+ InfoData.getU32(&Offset); // Length
+ uint16_t Version = InfoData.getU16(&Offset);
+ InfoData.getU32(&Offset); // Abbrev offset (should be zero)
+ uint8_t AddrSize = InfoData.getU8(&Offset);
+
+ uint32_t AbbrCode = InfoData.getULEB128(&Offset);
+
+ DataExtractor AbbrevData(Abbrev, true, 0);
+ uint32_t AbbrevOffset = getCUAbbrev(Abbrev, AbbrCode);
+ uint64_t Tag = AbbrevData.getULEB128(&AbbrevOffset);
+ (void)Tag;
+ // FIXME: Real error handling
+ assert(Tag == dwarf::DW_TAG_compile_unit);
+ // DW_CHILDREN
+ AbbrevData.getU8(&AbbrevOffset);
+ uint32_t Name;
+ uint32_t Form;
+ while ((Name = AbbrevData.getULEB128(&AbbrevOffset)) |
+ (Form = AbbrevData.getULEB128(&AbbrevOffset)) &&
+ Name != dwarf::DW_AT_GNU_dwo_id) {
+ DWARFFormValue::skipValue(Form, InfoData, &Offset, Version, AddrSize);
+ }
+ // FIXME: Real error handling
+ assert(Name == dwarf::DW_AT_GNU_dwo_id);
+ return InfoData.getU64(&Offset);
+}
+
+struct UnitIndexEntry {
+ uint64_t Signature;
+ DWARFUnitIndex::Entry::SectionContribution Contributions[8];
+};
+
+static void addAllTypes(std::vector<UnitIndexEntry> &TypeIndexEntries,
+ uint32_t OutTypesOffset, StringRef Types,
+ const UnitIndexEntry &CUEntry) {
+ uint32_t Offset = 0;
+ DataExtractor Data(Types, true, 0);
+ while (Data.isValidOffset(Offset)) {
+ TypeIndexEntries.push_back(CUEntry);
+ auto &Entry = TypeIndexEntries.back();
+ // Zero out the debug_info contribution
+ Entry.Contributions[0] = {};
+ auto &C = Entry.Contributions[DW_SECT_TYPES - DW_SECT_INFO];
+ C.Offset = OutTypesOffset + Offset;
+ auto PrevOffset = Offset;
+ // Length of the unit, including the 4 byte length field.
+ C.Length = Data.getU32(&Offset) + 4;
+
+ Data.getU16(&Offset); // Version
+ Data.getU32(&Offset); // Abbrev offset
+ Data.getU8(&Offset); // Address size
+ Entry.Signature = Data.getU64(&Offset);
+ Offset = PrevOffset + C.Length;
+ }
+}
+
+static void
+writeIndexTable(MCStreamer &Out, ArrayRef<unsigned> ContributionOffsets,
+ ArrayRef<UnitIndexEntry> IndexEntries,
+ uint32_t DWARFUnitIndex::Entry::SectionContribution::*Field) {
+ for (const auto &E : IndexEntries)
+ for (size_t i = 0; i != array_lengthof(E.Contributions); ++i)
+ if (ContributionOffsets[i])
+ Out.EmitIntValue(E.Contributions[i].*Field, 4);
+}
+
+static void writeIndex(MCStreamer &Out, MCSection *Section,
+ ArrayRef<unsigned> ContributionOffsets,
+ ArrayRef<UnitIndexEntry> IndexEntries) {
+ unsigned Columns = 0;
+ for (auto &C : ContributionOffsets)
+ if (C)
+ ++Columns;
+
+ std::vector<unsigned> Buckets(NextPowerOf2(3 * IndexEntries.size() / 2));
+ uint64_t Mask = Buckets.size() - 1;
+ for (size_t i = 0; i != IndexEntries.size(); ++i) {
+ auto S = IndexEntries[i].Signature;
+ auto H = S & Mask;
+ while (Buckets[H])
+ H += ((S >> 32) & Mask) | 1;
+ Buckets[H] = i + 1;
+ }
+
+ Out.SwitchSection(Section);
+ Out.EmitIntValue(2, 4); // Version
+ Out.EmitIntValue(Columns, 4); // Columns
+ Out.EmitIntValue(IndexEntries.size(), 4); // Num Units
+ Out.EmitIntValue(Buckets.size(), 4); // Num Buckets
+
+ // Write the signatures.
+ for (const auto &I : Buckets)
+ Out.EmitIntValue(I ? IndexEntries[I - 1].Signature : 0, 8);
+
+ // Write the indexes.
+ for (const auto &I : Buckets)
+ Out.EmitIntValue(I, 4);
+
+ // Write the column headers (which sections will appear in the table)
+ for (size_t i = 0; i != ContributionOffsets.size(); ++i)
+ if (ContributionOffsets[i])
+ Out.EmitIntValue(i + DW_SECT_INFO, 4);
+
+ // Write the offsets.
+ writeIndexTable(Out, ContributionOffsets, IndexEntries,
+ &DWARFUnitIndex::Entry::SectionContribution::Offset);
+
+ // Write the lengths.
+ writeIndexTable(Out, ContributionOffsets, IndexEntries,
+ &DWARFUnitIndex::Entry::SectionContribution::Length);
+}