[lld] [lld][ELF] Implement merged .debug_names section. (PR #86508)
via llvm-commits
llvm-commits at lists.llvm.org
Thu Mar 28 15:43:41 PDT 2024
================
@@ -2690,6 +2693,770 @@ static uint32_t computeGdbHash(StringRef s) {
return h;
}
+template <class ELFT>
+DebugNamesSection<ELFT>::DebugNamesSection()
+ : SyntheticSection(0, SHT_PROGBITS, 1, ".debug_names") {}
+
+template <class ELFT>
+template <class RelTy>
+void DebugNamesSection<ELFT>::getNameRelocsImpl(
+ InputSection *sec, ArrayRef<RelTy> rels,
+ DenseMap<uint32_t, uint32_t> &relocs) {
+ for (auto &rel : rels) {
+ Symbol &sym = sec->getFile<ELFT>()->getRelocTargetSym(rel);
+ relocs[rel.r_offset] = sym.getVA(getAddend<ELFT>(rel));
+ }
+}
+
+template <class ELFT>
+void DebugNamesSection<ELFT>::getNameRelocs(
+ InputSectionBase *base, DenseMap<uint32_t, uint32_t> &relocs) {
+ auto *sec = cast<InputSection>(base);
+ const RelsOrRelas<ELFT> rels = sec->template relsOrRelas<ELFT>();
+ if (rels.areRelocsRel())
+ getNameRelocsImpl(sec, rels.rels, relocs);
+ else
+ getNameRelocsImpl(sec, rels.relas, relocs);
+}
+
+template <class ELFT> void DebugNamesSection<ELFT>::writeTo(uint8_t *buf) {
+ SmallVector<uint32_t, 0> mergedCuOffsets;
+ SmallVector<uint32_t, 0> mergedTuOffsets;
+ DenseMap<uint32_t, uint32_t> strOffsets;
+ SmallVector<DenseMap<uint32_t, uint32_t>, 0> chunksRelocs;
+ chunksRelocs.reserve(numChunks);
+
+ for (size_t i = 0; i < numChunks; ++i) {
+ DebugNamesOutputChunk &chunk = outputChunks[i];
+ InputSectionBase *base = inputDebugNamesSections[i];
+ DenseMap<uint32_t, uint32_t> &relocs = chunksRelocs.emplace_back();
+ getNameRelocs(base, relocs);
+
+ // Update CuOffsets list with new data
+ for (uint32_t cuOffset : chunk.compilationUnits)
+ mergedCuOffsets.push_back(chunk.sec->outSecOff + cuOffset);
+
+ // TODO: Update TuOffsets list with new data
+ }
+
+ // Update the entries with the relocated string offsets.
+ for (auto &stringEntry : mergedEntries) {
+ uint32_t oldOffset = stringEntry.stringOffsetOffset;
+ uint32_t idx = stringEntry.chunkIdx;
+ stringEntry.relocatedEntryOffset = chunksRelocs[idx][oldOffset];
+ }
+
+ // Write out bytes for merged section.
+
+ // Write the header.
+ endian::write32<ELFT::TargetEndianness>(buf + 0, mergedHdr.UnitLength);
+ endian::write16<ELFT::TargetEndianness>(buf + 4, mergedHdr.Version);
+ endian::write32<ELFT::TargetEndianness>(buf + 8, mergedHdr.CompUnitCount);
+ endian::write32<ELFT::TargetEndianness>(buf + 12,
+ mergedHdr.LocalTypeUnitCount);
+ endian::write32<ELFT::TargetEndianness>(buf + 16,
+ mergedHdr.ForeignTypeUnitCount);
+ endian::write32<ELFT::TargetEndianness>(buf + 20, mergedHdr.BucketCount);
+ endian::write32<ELFT::TargetEndianness>(buf + 24, mergedHdr.NameCount);
+ endian::write32<ELFT::TargetEndianness>(buf + 28, mergedHdr.AbbrevTableSize);
+ endian::write32<ELFT::TargetEndianness>(buf + 32,
+ mergedHdr.AugmentationStringSize);
+ buf += 36;
+ memcpy(buf, mergedHdr.AugmentationString.c_str(), 8);
+ buf += 8;
+
+ // Write the CU list.
+ for (uint32_t offset : mergedCuOffsets) {
+ endian::write32<ELFT::TargetEndianness>(buf + 0, offset);
+ buf += 4;
+ }
+
+ // Write the local TU list.
+ // TODO: Fix this, once we get everything working without TUs.
+ if (mergedHdr.LocalTypeUnitCount != 0)
+ warn(".debug_names: type units are not handled in merged index");
+
+ // Write the foreign TU list.
+ // Currently LLVM does not emit foreign type units, so there should
+ // be nothing here to emit.
+ // TODO: Fix this, once we get everything working wtihout TUs.
+ if (mergedHdr.ForeignTypeUnitCount != 0)
+ warn(".debug_names: type units are not handled in merged index");
+
+ // Write the hash table.
+ // ... Write the buckets
+ uint32_t idx = 1;
+ for (const auto &bucket : bucketList) {
+ if (!bucket.empty())
+ endian::write32<ELFT::TargetEndianness>(buf + 0, idx);
+ idx += bucket.size();
+ buf += 4;
+ }
+
+ // ...Write the hashes
+ for (const auto &bucket : bucketList) {
+ for (const auto &entry : bucket) {
+ uint32_t hashValue = entry->hashValue;
+ endian::write32<ELFT::TargetEndianness>(buf + 0, hashValue);
+ buf += 4;
+ }
+ }
+
+ // Write the string offsets.
+ for (const auto &entry : mergedEntries) {
+ endian::write32<ELFT::TargetEndianness>(buf + 0,
+ entry.relocatedEntryOffset);
+ buf += 4;
+ }
+
+ // Write the entry offsets.
+ for (const auto &entry : mergedEntries) {
+ endian::write32<ELFT::TargetEndianness>(buf + 0, entry.entryOffset);
+ buf += 4;
+ }
+
+ // Write the abbrev table.
+ for (const auto *abbrev : mergedAbbrevTable) {
+ buf += encodeULEB128(abbrev->code, buf);
+ buf += encodeULEB128(abbrev->tag, buf);
+ for (auto attr : abbrev->attributes) {
+ buf += encodeULEB128(attr.Index, buf);
+ buf += encodeULEB128(attr.Form, buf);
+ }
+ endian::write16<ELFT::TargetEndianness>(buf + 0, 0); // attribute sentinels.
+ buf += 2;
+ }
+ *buf++ = 0; // abbrev table sentinel
+
+ // Write the entry pool.
+ for (const auto &stringEntry : mergedEntries) {
+ // Write all the entries for the string.
+ for (const auto &entry : stringEntry.indexEntries) {
+ buf += encodeULEB128(entry->abbrevCode, buf);
+ for (const auto &value : entry->attrValues) {
+ if (value.attrSize > 0) {
+ endian::write32<ELFT::TargetEndianness>(buf + 0, value.attrValue);
+ buf += value.attrSize;
+ }
+ }
+ }
+ *buf++ = 0; // Entry sentinel
+ }
+}
+
+template <class ELFT> bool DebugNamesSection<ELFT>::isNeeded() const {
+ return numChunks > 0;
+}
+
+template <class ELFT>
+static void readCompileUnitOffsets(
+ typename DebugNamesSection<ELFT>::DebugNamesSectionData &secData,
+ typename DebugNamesSection<ELFT>::DebugNamesOutputChunk &outputChunk,
+ DWARFDataExtractor &namesExtractor) {
+ uint64_t offset = secData.locs.CUsBase;
+ uint64_t *offsetPtr = &offset;
+ for (size_t i = 0; i < secData.hdr.CompUnitCount; ++i) {
+ Error err = Error::success();
+ // This call to namesExtractor can't fail; if there were a problem with the
+ // input, it would have been caught in the call to NamesIndex::extract, in
+ // DebugNamesSection::create.
+ uint32_t value = namesExtractor.getU32(offsetPtr, &err);
+ cantFail(std::move(err));
+ outputChunk.compilationUnits.push_back(value);
+ }
+}
+
+template <class ELFT>
+static void readEntryOffsets(
+ typename DebugNamesSection<ELFT>::DebugNamesSectionData &secData,
+ DWARFDataExtractor &namesExtractor) {
+ secData.entryOffsets = std::make_unique<uint32_t[]>(secData.hdr.NameCount);
+ uint64_t offset = secData.locs.EntryOffsetsBase;
+ uint64_t *offsetPtr = &offset;
+ for (size_t i = 0; i < secData.hdr.NameCount; ++i) {
+ Error err = Error::success();
+ // This call to namesExtractor can't fail; if there were a problem with the
+ // input, it would have been caught in the call to NamesIndex::extract, in
+ // DebugNamesSection::create.
+ uint32_t value = namesExtractor.getU32(offsetPtr, &err);
+ cantFail(std::move(err));
+ secData.entryOffsets.get()[i] = value;
+ }
+}
+
+template <class ELFT>
+static void readAttributeValues(
+ SmallVector<typename DebugNamesSection<ELFT>::AttrValueData, 3> &values,
+ typename DebugNamesSection<ELFT>::DebugNamesInputChunk &chunk,
+ uint64_t &offset,
+ typename DebugNamesSection<ELFT>::DebugNamesSectionData &secData,
+ int32_t &parentOffset, DWARFDataExtractor &namesExtractor,
+ const DWARFDebugNames::Abbrev &abbrev) {
+ const LLDDWARFSection &namesSection = *chunk.namesSection;
+ uint64_t *offsetPtr = &offset;
+ typename DebugNamesSection<ELFT>::AttrValueData cuOrTuAttr = {0, 0};
+ for (auto attr : abbrev.Attributes) {
+ Error err = Error::success();
+ typename DebugNamesSection<ELFT>::AttrValueData newAttr;
+ uint32_t value;
+ if (attr.Index == DW_IDX_parent && attr.Form != DW_FORM_flag_present &&
+ attr.Form != DW_FORM_ref4)
+ errorOrWarn(toString(namesSection.sec) +
+ Twine(": invalid form for DW_IDX_parent"));
+ switch (attr.Form) {
+ case DW_FORM_flag_present: {
+ // Currently only DW_IDX_parent attributes (in .debug_names) can
+ // have this form. This form does not have a real value (nothing is
+ // emitted for it).
+ if (attr.Index != DW_IDX_parent)
+ errorOrWarn(toString(namesSection.sec) +
+ Twine(": invalid form for attribute"));
+ break;
+ }
+ case DW_FORM_data1:
+ case DW_FORM_ref1: {
+ newAttr.attrValue = namesExtractor.getU8(offsetPtr, &err);
+ newAttr.attrSize = 1;
+ break;
+ }
+ case DW_FORM_data2:
+ case DW_FORM_ref2: {
+ value = namesExtractor.getU16(offsetPtr, &err);
+ newAttr.attrValue = value;
+ newAttr.attrSize = 2;
+ break;
+ }
+ case DW_FORM_data4:
+ case DW_FORM_ref4: {
+ value = namesExtractor.getU32(offsetPtr, &err);
+ newAttr.attrValue = value;
+ newAttr.attrSize = 4;
+ if (attr.Index == dwarf::DW_IDX_parent)
+ parentOffset = value + secData.locs.EntriesBase;
+ break;
+ }
+ case DW_FORM_data8:
+ case DW_FORM_ref8:
+ case DW_FORM_ref_sig8: {
+ value = namesExtractor.getU64(offsetPtr, &err);
+ newAttr.attrValue = value;
+ newAttr.attrSize = 8;
+ break;
+ }
+ default: {
+ errorOrWarn(toString(namesSection.sec) +
+ Twine(": unrecognized form encoding ") + Twine(attr.Form) +
+ Twine(" in .debug_names abbrev table"));
+ break;
+ }
+ }
+ if (err)
+ errorOrWarn(toString(namesSection.sec) +
+ Twine(": error while reading attributes: ") +
+ toString(std::move(err)));
+ if (attr.Index == DW_IDX_compile_unit || attr.Index == DW_IDX_type_unit)
+ // Save it to put it at the end of the attributes list.
+ cuOrTuAttr = newAttr;
+ else if (attr.Form != DW_FORM_flag_present)
+ values.push_back(newAttr);
+ }
+
+ // Make sure the CU or TU index attribute is the last one in the list.
+ values.push_back(cuOrTuAttr);
+}
+
+template <class ELFT>
+static void
+readEntry(typename DebugNamesSection<ELFT>::NamedEntry &stringEntry,
+ typename DebugNamesSection<ELFT>::DebugNamesInputChunk &chunk,
+ typename DebugNamesSection<ELFT>::DebugNamesSectionData &secData,
+ DWARFDataExtractor &namesExtractor,
+ const DWARFDebugNames::NameIndex &ni) {
+ std::unique_ptr<LLDDWARFSection> &namesSection = chunk.namesSection;
+ uint64_t offset = stringEntry.entryOffset;
+ // Each entry ends with a zero 'sentinel' value
+ while (offset < namesSection->Data.size() &&
+ namesSection->Data[offset] != 0) {
+ // Read & store all entries (for the same string)
+ auto entry =
+ std::make_unique<typename DebugNamesSection<ELFT>::IndexEntry>();
+ entry->poolOffset = offset;
+ Error err = Error::success();
+ // This call to namesExtractor can't fail; if there were a problem with the
+ // input, it would have been caught in the call to NamesIndex::extract, in
+ // DebugNamesSection::create.
+ uint64_t ulebValue = namesExtractor.getULEB128(&offset, &err);
+ cantFail(std::move(err));
+ entry->abbrevCode = static_cast<uint32_t>(ulebValue);
+ const auto &abbrevs = ni.getAbbrevs();
+ auto abbrevIt = abbrevs.find_as(entry->abbrevCode);
+ if (abbrevIt != abbrevs.end()) {
+ const DWARFDebugNames::Abbrev &abbrev = *abbrevIt;
+ readAttributeValues<ELFT>(entry->attrValues, chunk, offset, secData,
+ entry->parentOffset, namesExtractor, abbrev);
+ stringEntry.indexEntries.push_back(std::move(entry));
+ } else
+ errorOrWarn(toString(chunk.namesSection->sec) +
+ Twine(": invalid abbrev code in entry"));
+ }
+ if (offset >= namesSection->Data.size())
+ errorOrWarn(
+ toString(chunk.namesSection->sec) +
+ Twine(": encountered unexpected end of section while reading entry"));
+}
+
+template <class ELFT>
+static void
+readEntries(typename DebugNamesSection<ELFT>::DebugNamesSectionData &secData,
+ typename DebugNamesSection<ELFT>::DebugNamesInputChunk &chunk,
+ DWARFDataExtractor &namesExtractor, DataExtractor &strExtractor,
+ const DWARFDebugNames::NameIndex &ni) {
+ // Temporary map from entry offsets to address (pointer) of entry with that
+ // offset; used to find parent entries quickly.
+ DenseMap<uint32_t, typename DebugNamesSection<ELFT>::IndexEntry *> offsetMap;
+ // Reserve sizes for this chunk's hashes & namedEntries.
+ chunk.hashValues.reserve(secData.hdr.NameCount);
+ secData.namedEntries.reserve(secData.hdr.NameCount);
+ // Calculate the Entry Offsets, create initial records.
+ for (uint32_t i = 0, e = secData.hdr.NameCount; i != e; ++i) {
+ // Get string value
+ typename DebugNamesSection<ELFT>::NamedEntry stringEntry;
+ stringEntry.entryOffset =
+ secData.locs.EntriesBase + secData.entryOffsets[i];
+ uint64_t strOffsetOffset =
+ secData.locs.StringOffsetsBase + i * secData.dwarfSize;
+ stringEntry.stringOffsetOffset = strOffsetOffset;
+ uint64_t strOffset =
+ namesExtractor.getRelocatedValue(secData.dwarfSize, &strOffsetOffset);
+ StringRef name = strExtractor.getCStrRef(&strOffset);
+ stringEntry.name = name.data();
+ // Calculate hash
+ stringEntry.hashValue = caseFoldingDjbHash(name);
+ chunk.hashValues.push_back(stringEntry.hashValue);
+ // Read String Entry
+ readEntry<ELFT>(stringEntry, chunk, secData, namesExtractor, ni);
+ // Add index entries & offsets to our temporary map
+ for (const auto &entry : stringEntry.indexEntries)
+ offsetMap[entry->poolOffset] = entry.get();
+ secData.namedEntries.push_back(std::move(stringEntry));
+ }
+ // Find/assign pointers to any 'real' parent entries (needed to find correct
+ // parent entry offsets in merged data).
+ for (auto &stringEntry : secData.namedEntries)
+ for (auto &entry : stringEntry.indexEntries)
+ if (entry->parentOffset != -1)
+ entry->parentEntry = offsetMap[entry->parentOffset];
+}
+
+static uint16_t computeDebugNamesHeaderSize() {
+ // Size of the .debug_names section header, in bytes, for DWARF32:
+ uint16_t size = /* unit length */ 4 +
+ /* version */ 2 +
+ /* padding */ 2 +
+ /* CU count */ 4 +
+ /* TU count */ 4 +
+ /* Foreign TU count */ 4 +
+ /* Bucket Count */ 4 +
+ /* Name Count */ 4 +
+ /* Abbrev table size */ 4 +
+ /* Augmentation string size */ 4 +
+ /* augmentation string */ 8;
+ return size;
+}
+
+template <class ELFT>
+static void collectDebugNamesSectionData(
+ typename DebugNamesSection<ELFT>::DebugNamesInputChunk &chunk,
+ typename DebugNamesSection<ELFT>::DebugNamesOutputChunk &outputChunk,
+ DWARFDataExtractor &namesExtractor, DataExtractor &strExtractor) {
+ for (const auto &ni : *chunk.debugNamesData) {
+ typename DebugNamesSection<ELFT>::DebugNamesSectionData secData;
+ secData.hdr = ni.getHeader();
+ if (secData.hdr.Format != DwarfFormat::DWARF32) {
+ errorOrWarn(toString(chunk.namesSection->sec) +
+ Twine(": unsupported DWARF64"));
+ // Don't try to continue; we can't parse DWARF64 at the moment.
+ return;
+ }
+ secData.dwarfSize = dwarf::getDwarfOffsetByteSize(DwarfFormat::DWARF32);
+ secData.hdrSize = computeDebugNamesHeaderSize();
+ if (secData.hdr.Version != 5)
+ errorOrWarn(toString(chunk.namesSection->sec) +
+ Twine(": unsupported version"));
+ findDebugNamesOffsets(secData.locs, secData.hdrSize, secData.hdr.Format,
+ secData.hdr);
+ readCompileUnitOffsets<ELFT>(secData, outputChunk, namesExtractor);
+ readEntryOffsets<ELFT>(secData, namesExtractor);
+ readEntries<ELFT>(secData, chunk, namesExtractor, strExtractor, ni);
+ chunk.sectionsData.push_back(std::move(secData));
+ }
+}
+
+template <class ELFT>
+void DebugNamesSection<ELFT>::collectMergedCounts(
+ MutableArrayRef<DebugNamesInputChunk> &inputChunks) {
+ SmallVector<uint32_t, 0> tmpMergedCuOffsets;
+ mergedHdr.CompUnitCount = 0;
+ mergedHdr.LocalTypeUnitCount = 0;
+ mergedHdr.ForeignTypeUnitCount = 0;
+ mergedHdr.Version = 5;
+ mergedHdr.Format = DwarfFormat::DWARF32;
+ mergedHdr.AugmentationStringSize = 0;
+
+ for (size_t i = 0; i < numChunks; ++i) {
+ DebugNamesInputChunk &inputChunk = inputChunks[i];
+ DebugNamesOutputChunk &outputChunk = outputChunks[i];
+ inputChunk.baseCuOffsetIdx = tmpMergedCuOffsets.size();
+ for (uint32_t cuOffset : outputChunk.compilationUnits)
+ tmpMergedCuOffsets.push_back(outputChunk.sec->outSecOff + cuOffset);
+ for (const DebugNamesSectionData &data : inputChunk.sectionsData) {
+ mergedHdr.CompUnitCount += data.hdr.CompUnitCount;
+ mergedHdr.LocalTypeUnitCount += data.hdr.LocalTypeUnitCount;
+ mergedHdr.ForeignTypeUnitCount += data.hdr.ForeignTypeUnitCount;
+ // Set & check the Augmentation String.
+ if (mergedHdr.AugmentationStringSize == 0) {
+ mergedHdr.AugmentationStringSize = data.hdr.AugmentationStringSize;
+ mergedHdr.AugmentationString = data.hdr.AugmentationString;
+ } else if ((mergedHdr.AugmentationStringSize !=
+ data.hdr.AugmentationStringSize) ||
+ (mergedHdr.AugmentationString !=
+ data.hdr.AugmentationString)) {
+ // There are conflicting augmentation strings, so it's best for the
+ // merged index to not use an augmentation string.
+ mergedHdr.AugmentationStringSize = 8;
+ mergedHdr.AugmentationString = " ";
+ }
+ }
+ }
+}
+
+template <class ELFT>
+void DebugNamesSection<ELFT>::Abbrev::Profile(FoldingSetNodeID &id) const {
+ id.AddInteger(tag);
+ for (const DWARFDebugNames::AttributeEncoding &attr : attributes) {
+ id.AddInteger(attr.Index);
+ id.AddInteger(attr.Form);
+ }
+}
+
+template <class ELFT>
+std::pair<uint8_t, dwarf::Form> DebugNamesSection<ELFT>::getMergedCuSizeData() {
+ // Once we've merged all the CU offsets into a single list, the original
+ // DWARF form/size (often 1 byte) may be too small to hold indices to all
+ // the offsets. Here we calculate what the right form/size needs to be for
+ // the merged index.
+ uint8_t size;
+ dwarf::Form form;
+ // TODO: Investigate possibly using DIEInteger::BestForm here
+ if (mergedHdr.CompUnitCount > 0xffffffff) {
+ form = DW_FORM_data8;
+ size = 8;
+ } else if (mergedHdr.CompUnitCount > 0xffff) {
+ form = DW_FORM_data4;
+ size = 4;
+ } else if (mergedHdr.CompUnitCount > 0xff) {
+ form = DW_FORM_data2;
+ size = 2;
+ } else {
+ form = DW_FORM_data1;
+ size = 1;
+ }
+
+ return {size, form};
+}
+
+template <class ELFT>
+void DebugNamesSection<ELFT>::getMergedAbbrevTable(
+ MutableArrayRef<DebugNamesInputChunk> &inputChunks) {
+ MapVector<uint64_t, Abbrev> abbrevMap;
+ FoldingSet<Abbrev> AbbreviationsSet;
+
+ // Need to determine what size form is needed for the DW_IDX_compile_unit
+ // attributes in the merged index. Will need to update the abbrevs to use
+ // the right form.
+ dwarf::Form compileUnitAttrForm = getMergedCuSizeData().second;
+
+ for (DebugNamesInputChunk &chunk : inputChunks) {
+ for (const auto &ni : *chunk.debugNamesData) {
+ const auto &abbrevs = ni.getAbbrevs();
+ for (const DWARFDebugNames::Abbrev &abbrev : abbrevs) {
+ // Create canonicalized abbrev.
+ Abbrev newAbbrev;
+ DWARFDebugNames::AttributeEncoding cuOrTuAttr(DW_IDX_compile_unit,
+ compileUnitAttrForm);
+ newAbbrev.code = abbrev.Code;
+ newAbbrev.tag = abbrev.Tag;
+ for (const auto attr : abbrev.Attributes) {
+ DWARFDebugNames::AttributeEncoding newAttr(attr.Index, attr.Form);
+ if (attr.Index == DW_IDX_compile_unit ||
+ attr.Index == DW_IDX_type_unit)
+ // Save it, to put it at the end.
+ cuOrTuAttr.Index = newAttr.Index;
+ else
+ newAbbrev.attributes.push_back(newAttr);
+ }
+ // Put the CU/TU index at the end of the attributes list.
+ newAbbrev.attributes.push_back(cuOrTuAttr);
+
+ // Next, check our abbreviations set to see if we've already seen the
+ // identical abbreviation.
+ uint32_t oldCode = newAbbrev.code;
+ uint32_t newCode;
+ FoldingSetNodeID id;
+ newAbbrev.Profile(id);
+ void *insertPos;
+ if (Abbrev *Existing =
+ AbbreviationsSet.FindNodeOrInsertPos(id, insertPos)) {
+ // Found it; we've already seen an identical abbreviation.
+ newCode = Existing->code;
+ } else {
+ // Didn't find it.
+ Abbrev *newAbbrev2 = new (Alloc) Abbrev(std::move(newAbbrev));
+ AbbreviationsSet.InsertNode(newAbbrev2, insertPos);
+ newCode = mergedAbbrevTable.size() + 1;
+ newAbbrev2->code = newCode;
+ mergedAbbrevTable.push_back(newAbbrev2);
+ }
+ chunk.abbrevCodeMap[oldCode] = newCode;
+ }
+ }
+ }
+
+ // Calculate the merged abbrev table size.
+ mergedHdr.AbbrevTableSize = 0;
+ for (Abbrev *a : mergedAbbrevTable) {
+ mergedHdr.AbbrevTableSize += getULEB128Size(a->code);
+ mergedHdr.AbbrevTableSize += getULEB128Size(a->tag);
+ for (const auto &attr : a->attributes) {
+ mergedHdr.AbbrevTableSize += getULEB128Size(attr.Index);
+ mergedHdr.AbbrevTableSize += getULEB128Size(attr.Form);
+ }
+ mergedHdr.AbbrevTableSize += 2; // attribute index & form sentinels
+ }
+ ++mergedHdr.AbbrevTableSize; // abbrev table sentinel
+}
+
+template <class ELFT>
+void DebugNamesSection<ELFT>::getMergedSymbols(
+ MutableArrayRef<DebugNamesInputChunk> &inputChunks) {
+ // The number of symbols (& abbrevs) we will handle is very large; will use
+ // multi-threading to speed it up.
+ constexpr size_t numShards = 32;
+ const size_t concurrency =
+ bit_floor(std::min<size_t>(config->threadCount, numShards));
+ const size_t shift = 32 - countr_zero(numShards);
+
+ struct ShardData {
+ // Map to uniquify symbols by name
+ MapVector<CachedHashStringRef, NamedEntry> nameMap;
+ };
+
+ // Need to determine what size is needed for the DW_IDX_compile_unit
+ // attributes in the merged index. Will need to update the indexEntries
+ // to use the right size.
+ uint8_t compileUnitAttrSize = getMergedCuSizeData().first;
+
+ auto shardsPtr = std::make_unique<ShardData[]>(numShards);
+ MutableArrayRef<ShardData> shards(shardsPtr.get(), numShards);
+
+ parallelFor(0, concurrency, [&](size_t threadId) {
+ for (size_t i = 0; i < numChunks; ++i) {
+ DebugNamesInputChunk &chunk = inputChunks[i];
+ for (auto &secData : chunk.sectionsData) {
+ // Deduplicate the NamedEntry records (based on the string/name),
+ // using a map from string/name to NamedEntry records.
+ // Note there is a twist: If there is already a record for the current
+ // 'string' in the nameMap, we append all the indexEntries from the
+ // current record to the record that's in the nameMap. I.e. we
+ // deduplicate the *strings* but we keep all the IndexEntry records
+ // (moving them to the appropriate 'kept' NamedEntry record).
+ for (auto &stringEntry : secData.namedEntries) {
+ size_t shardId = stringEntry.hashValue >> shift;
+ if ((shardId & (concurrency - 1)) != threadId)
+ continue;
+
+ auto &shard = shards[shardId];
+ stringEntry.chunkIdx = i;
+ for (auto &entry : stringEntry.indexEntries) {
+ // The DW_IDX_compile_unit is always the last attribute (we set it
+ // up that way when we read/created the attributes). We need to
+ // update the index value to use the correct merged offset, and we
+ // need to fix the size of the index attribute.
+ uint8_t endPos = entry->attrValues.size() - 1;
+ entry->attrValues[endPos].attrValue += chunk.baseCuOffsetIdx;
+ entry->attrValues[endPos].attrSize = compileUnitAttrSize;
+ // Update the entry's abbrev code to match the merged
+ // abbreviations.
+ entry->abbrevCode = chunk.abbrevCodeMap[entry->abbrevCode];
+ }
+
+ CachedHashStringRef cachedHashName(stringEntry.name);
+ auto [it, inserted] =
+ shard.nameMap.try_emplace(cachedHashName, std::move(stringEntry));
+ if (!inserted) {
+ // Found the string already; don't add to map, but append
+ // entry/entries for it to existing map entry.
+ NamedEntry &found = it->second;
+ // Append the entries...
+ for (auto &entry : stringEntry.indexEntries)
+ found.indexEntries.push_back(std::move(entry));
+ }
+ }
+ }
+ }
+ });
+
+ // Combined the shared symbols into mergedEntries
+ for (auto &shard : shards)
+ for (auto &mapEntry : shard.nameMap)
+ mergedEntries.push_back(std::move(mapEntry.second));
+ mergedHdr.NameCount = mergedEntries.size();
+}
+
+template <class ELFT>
+void DebugNamesSection<ELFT>::computeUniqueHashes(
+ MutableArrayRef<DebugNamesInputChunk> &chunks) {
+ SmallVector<uint32_t, 0> uniques;
----------------
cmtice wrote:
I am aware of that, but for some reason LLD does not adhere to that particular rule. You can see this throughout all the LLD code. LLD uses camel case, for variable names, but they always start with a lowercase letter.
https://github.com/llvm/llvm-project/pull/86508
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