Author: David Blaikie Date: 2020-08-18T10:49:39-07:00 New Revision: f7a49d2aa691266497c4baa35f29ba0167b39d23
URL: https://github.com/llvm/llvm-project/commit/f7a49d2aa691266497c4baa35f29ba0167b39d23 DIFF: https://github.com/llvm/llvm-project/commit/f7a49d2aa691266497c4baa35f29ba0167b39d23.diff LOG: [WIP][DebugInfo] Lazily parse debug_loclist offsets Parsing DWARFv5 debug_loclist offsets when a CU is parsed is weighing down memory usage of symbolizers that don't need to parse this data at all. There's not much benefit to caching these anyway - since they are O(1) lookup and reading once you know where the offset list starts (and can do bounds checking with the offset list size too). In general, I think it might be time to start paying down some of the technical debt of loc/loclist/range/rnglist parsing to try to unify it a bit more. eg: * Currently DWARFUnit has: RangeSection, RangeSectionBase, LocSection, LocSectionBase, LocTable, RngListTable, LoclistTableHeader (be nice if these were all wrapped up in two variables - one for loclists, one for rnglists) * rnglists and loclists are handled differently (see: LoclistTableHeader, but no RnglistTableHeader) * maybe all these types could be less stateful - lazily parse what they need to, even reparsing rather than caching because it doesn't seem too expensive, for instance. (though admittedly so long as it's constantcost/overead per compilatiton that's probably adequate) * Maybe implementing and using a DWARFDataExtractor that can be sub-ranged (so we could slice it up to just the single contribution) - though maybe that's not so useful because loc/ranges need to refer to it by absolute, not contribution-relative mechanisms Differential Revision: https://reviews.llvm.org/D86110 Added: Modified: lldb/source/Plugins/SymbolFile/DWARF/DWARFUnit.h lldb/test/Shell/SymbolFile/DWARF/DW_AT_loclists_base.s llvm/include/llvm/DebugInfo/DWARF/DWARFDebugLoc.h llvm/include/llvm/DebugInfo/DWARF/DWARFListTable.h llvm/include/llvm/DebugInfo/DWARF/DWARFUnit.h llvm/lib/DebugInfo/DWARF/DWARFContext.cpp llvm/lib/DebugInfo/DWARF/DWARFListTable.cpp llvm/lib/DebugInfo/DWARF/DWARFUnit.cpp Removed: ################################################################################ diff --git a/lldb/source/Plugins/SymbolFile/DWARF/DWARFUnit.h b/lldb/source/Plugins/SymbolFile/DWARF/DWARFUnit.h index affad286a490..1d8236c4ed42 100644 --- a/lldb/source/Plugins/SymbolFile/DWARF/DWARFUnit.h +++ b/lldb/source/Plugins/SymbolFile/DWARF/DWARFUnit.h @@ -237,7 +237,9 @@ class DWARFUnit : public lldb_private::UserID { llvm::Optional<uint64_t> GetRnglistOffset(uint32_t Index) const { if (!m_rnglist_table) return llvm::None; - if (llvm::Optional<uint64_t> off = m_rnglist_table->getOffsetEntry(Index)) + if (llvm::Optional<uint64_t> off = m_rnglist_table->getOffsetEntry( + m_dwarf.GetDWARFContext().getOrLoadRngListsData().GetAsLLVM(), + Index)) return *off + m_ranges_base; return llvm::None; } @@ -246,7 +248,8 @@ class DWARFUnit : public lldb_private::UserID { if (!m_loclist_table_header) return llvm::None; - llvm::Optional<uint64_t> Offset = m_loclist_table_header->getOffsetEntry(Index); + llvm::Optional<uint64_t> Offset = m_loclist_table_header->getOffsetEntry( + m_dwarf.GetDWARFContext().getOrLoadLocListsData().GetAsLLVM(), Index); if (!Offset) return llvm::None; return *Offset + m_loclists_base; diff --git a/lldb/test/Shell/SymbolFile/DWARF/DW_AT_loclists_base.s b/lldb/test/Shell/SymbolFile/DWARF/DW_AT_loclists_base.s index ca32e9930a76..6ff35f8c6596 100644 --- a/lldb/test/Shell/SymbolFile/DWARF/DW_AT_loclists_base.s +++ b/lldb/test/Shell/SymbolFile/DWARF/DW_AT_loclists_base.s @@ -5,7 +5,7 @@ # CHECK-LABEL: image lookup -v -s lookup_loclists # CHECK: Variable: {{.*}}, name = "x0", type = "int", location = DW_OP_reg0 RAX, -# CHECK: Variable: {{.*}}, name = "x1", type = "int", location = , +# CHECK-NOT: Variable: loclists: nop @@ -28,7 +28,7 @@ lookup_loclists: .short 5 # Version .byte 8 # Address size .byte 0 # Segment selector size - .long 1 # Offset entry count + .long 2 # Offset entry count .Lloclists_table_base: .long .Ldebug_loc0-.Lloclists_table_base .long .Ldebug_loc1-.Lloclists_table_base diff --git a/llvm/include/llvm/DebugInfo/DWARF/DWARFDebugLoc.h b/llvm/include/llvm/DebugInfo/DWARF/DWARFDebugLoc.h index 3b141304f85f..dbc11c51a789 100644 --- a/llvm/include/llvm/DebugInfo/DWARF/DWARFDebugLoc.h +++ b/llvm/include/llvm/DebugInfo/DWARF/DWARFDebugLoc.h @@ -72,6 +72,8 @@ class DWARFLocationTable { std::function<Optional<object::SectionedAddress>(uint32_t)> LookupAddr, function_ref<bool(Expected<DWARFLocationExpression>)> Callback) const; + const DWARFDataExtractor &getData() { return Data; } + protected: DWARFDataExtractor Data; diff --git a/llvm/include/llvm/DebugInfo/DWARF/DWARFListTable.h b/llvm/include/llvm/DebugInfo/DWARF/DWARFListTable.h index 496fdb2477f9..bcfc71381aee 100644 --- a/llvm/include/llvm/DebugInfo/DWARF/DWARFListTable.h +++ b/llvm/include/llvm/DebugInfo/DWARF/DWARFListTable.h @@ -72,10 +72,6 @@ class DWARFListTableHeader { }; Header HeaderData; - /// The offset table, which contains offsets to the individual list entries. - /// It is used by forms such as DW_FORM_rnglistx. - /// FIXME: Generate the table and use the appropriate forms. - std::vector<uint64_t> Offsets; /// The table's format, either DWARF32 or DWARF64. dwarf::DwarfFormat Format; /// The offset at which the header (and hence the table) is located within @@ -93,7 +89,6 @@ class DWARFListTableHeader { void clear() { HeaderData = {}; - Offsets.clear(); } uint64_t getHeaderOffset() const { return HeaderOffset; } uint8_t getAddrSize() const { return HeaderData.AddrSize; } @@ -115,11 +110,17 @@ class DWARFListTableHeader { llvm_unreachable("Invalid DWARF format (expected DWARF32 or DWARF64"); } - void dump(raw_ostream &OS, DIDumpOptions DumpOpts = {}) const; - Optional<uint64_t> getOffsetEntry(uint32_t Index) const { - if (Index < Offsets.size()) - return Offsets[Index]; - return None; + void dump(DataExtractor Data, raw_ostream &OS, + DIDumpOptions DumpOpts = {}) const; + Optional<uint64_t> getOffsetEntry(DataExtractor Data, uint32_t Index) const { + if (Index > HeaderData.OffsetEntryCount) + return None; + + uint8_t OffsetByteSize = Format == dwarf::DWARF64 ? 8 : 4; + uint64_t Offset = + getHeaderOffset() + getHeaderSize(Format) + OffsetByteSize * Index; + auto R = Data.getUnsigned(&Offset, OffsetByteSize); + return R; } /// Extract the table header and the array of offsets. @@ -169,14 +170,14 @@ template <typename DWARFListType> class DWARFListTableBase { uint8_t getAddrSize() const { return Header.getAddrSize(); } dwarf::DwarfFormat getFormat() const { return Header.getFormat(); } - void dump(raw_ostream &OS, + void dump(DWARFDataExtractor Data, raw_ostream &OS, llvm::function_ref<Optional<object::SectionedAddress>(uint32_t)> LookupPooledAddress, DIDumpOptions DumpOpts = {}) const; /// Return the contents of the offset entry designated by a given index. - Optional<uint64_t> getOffsetEntry(uint32_t Index) const { - return Header.getOffsetEntry(Index); + Optional<uint64_t> getOffsetEntry(DataExtractor Data, uint32_t Index) const { + return Header.getOffsetEntry(Data, Index); } /// Return the size of the table header including the length but not including /// the offsets. This is dependent on the table format, which is unambiguously @@ -240,11 +241,11 @@ Error DWARFListType<ListEntryType>::extract(DWARFDataExtractor Data, template <typename DWARFListType> void DWARFListTableBase<DWARFListType>::dump( - raw_ostream &OS, + DWARFDataExtractor Data, raw_ostream &OS, llvm::function_ref<Optional<object::SectionedAddress>(uint32_t)> LookupPooledAddress, DIDumpOptions DumpOpts) const { - Header.dump(OS, DumpOpts); + Header.dump(Data, OS, DumpOpts); OS << HeaderString << "\n"; // Determine the length of the longest encoding string we have in the table, diff --git a/llvm/include/llvm/DebugInfo/DWARF/DWARFUnit.h b/llvm/include/llvm/DebugInfo/DWARF/DWARFUnit.h index 1613e74d4a36..c76ee5efa37b 100644 --- a/llvm/include/llvm/DebugInfo/DWARF/DWARFUnit.h +++ b/llvm/include/llvm/DebugInfo/DWARF/DWARFUnit.h @@ -412,18 +412,13 @@ class DWARFUnit { /// Return a rangelist's offset based on an index. The index designates /// an entry in the rangelist table's offset array and is supplied by /// DW_FORM_rnglistx. - Optional<uint64_t> getRnglistOffset(uint32_t Index) { - if (!RngListTable) - return None; - if (Optional<uint64_t> Off = RngListTable->getOffsetEntry(Index)) - return *Off + RangeSectionBase; - return None; - } + Optional<uint64_t> getRnglistOffset(uint32_t Index); Optional<uint64_t> getLoclistOffset(uint32_t Index) { if (!LoclistTableHeader) return None; - if (Optional<uint64_t> Off = LoclistTableHeader->getOffsetEntry(Index)) + if (Optional<uint64_t> Off = + LoclistTableHeader->getOffsetEntry(LocTable->getData(), Index)) return *Off + getLocSectionBase(); return None; } diff --git a/llvm/lib/DebugInfo/DWARF/DWARFContext.cpp b/llvm/lib/DebugInfo/DWARF/DWARFContext.cpp index 3bcde8fafb1f..96ba57946833 100644 --- a/llvm/lib/DebugInfo/DWARF/DWARFContext.cpp +++ b/llvm/lib/DebugInfo/DWARF/DWARFContext.cpp @@ -255,7 +255,7 @@ static void dumpRnglistsSection( break; Offset = TableOffset + Length; } else { - Rnglists.dump(OS, LookupPooledAddress, DumpOpts); + Rnglists.dump(rnglistData, OS, LookupPooledAddress, DumpOpts); } } } @@ -316,7 +316,7 @@ static void dumpLoclistsSection(raw_ostream &OS, DIDumpOptions DumpOpts, return; } - Header.dump(OS, DumpOpts); + Header.dump(Data, OS, DumpOpts); uint64_t EndOffset = Header.length() + Header.getHeaderOffset(); Data.setAddressSize(Header.getAddrSize()); diff --git a/llvm/lib/DebugInfo/DWARF/DWARFListTable.cpp b/llvm/lib/DebugInfo/DWARF/DWARFListTable.cpp index 2124a49bef60..c876af1e9b51 100644 --- a/llvm/lib/DebugInfo/DWARF/DWARFListTable.cpp +++ b/llvm/lib/DebugInfo/DWARF/DWARFListTable.cpp @@ -71,12 +71,12 @@ Error DWARFListTableHeader::extract(DWARFDataExtractor Data, ") than there is space for", SectionName.data(), HeaderOffset, HeaderData.OffsetEntryCount); Data.setAddressSize(HeaderData.AddrSize); - for (uint32_t I = 0; I < HeaderData.OffsetEntryCount; ++I) - Offsets.push_back(Data.getRelocatedValue(OffsetByteSize, OffsetPtr)); + *OffsetPtr += HeaderData.OffsetEntryCount * OffsetByteSize; return Error::success(); } -void DWARFListTableHeader::dump(raw_ostream &OS, DIDumpOptions DumpOpts) const { +void DWARFListTableHeader::dump(DataExtractor Data, raw_ostream &OS, + DIDumpOptions DumpOpts) const { if (DumpOpts.Verbose) OS << format("0x%8.8" PRIx64 ": ", HeaderOffset); int OffsetDumpWidth = 2 * dwarf::getDwarfOffsetByteSize(Format); @@ -91,7 +91,8 @@ void DWARFListTableHeader::dump(raw_ostream &OS, DIDumpOptions DumpOpts) const { if (HeaderData.OffsetEntryCount > 0) { OS << "offsets: ["; - for (const auto &Off : Offsets) { + for (uint32_t I = 0; I < HeaderData.OffsetEntryCount; ++I) { + auto Off = *getOffsetEntry(Data, I); OS << format("\n0x%0*" PRIx64, OffsetDumpWidth, Off); if (DumpOpts.Verbose) OS << format(" => 0x%08" PRIx64, diff --git a/llvm/lib/DebugInfo/DWARF/DWARFUnit.cpp b/llvm/lib/DebugInfo/DWARF/DWARFUnit.cpp index 0527f29d1a1a..b871e6ebdca5 100644 --- a/llvm/lib/DebugInfo/DWARF/DWARFUnit.cpp +++ b/llvm/lib/DebugInfo/DWARF/DWARFUnit.cpp @@ -548,17 +548,13 @@ Error DWARFUnit::tryExtractDIEsIfNeeded(bool CUDieOnly) { uint64_t HeaderSize = DWARFListTableHeader::getHeaderSize(Header.getFormat()); uint64_t Offset = getLocSectionBase(); - DWARFDataExtractor Data(Context.getDWARFObj(), *LocSection, - isLittleEndian, getAddressByteSize()); + const DWARFDataExtractor &Data = LocTable->getData(); if (Offset < HeaderSize) return createStringError(errc::invalid_argument, "did not detect a valid" " list table with base = 0x%" PRIx64 "\n", Offset); Offset -= HeaderSize; - if (auto *IndexEntry = Header.getIndexEntry()) - if (const auto *Contrib = IndexEntry->getContribution(DW_SECT_LOCLISTS)) - Offset += Contrib->Offset; if (Error E = LoclistTableHeader->extract(Data, &Offset)) return createStringError(errc::invalid_argument, "parsing a loclist table: " + @@ -1009,3 +1005,13 @@ DWARFUnit::determineStringOffsetsTableContributionDWO(DWARFDataExtractor & DA) { return DescOrError.takeError(); return *DescOrError; } + +Optional<uint64_t> DWARFUnit::getRnglistOffset(uint32_t Index) { + if (!RngListTable) + return None; + DataExtractor RangesData(RangeSection->Data, isLittleEndian, + getAddressByteSize()); + if (Optional<uint64_t> Off = RngListTable->getOffsetEntry(RangesData, Index)) + return *Off + RangeSectionBase; + return None; +} _______________________________________________ lldb-commits mailing list lldb-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/lldb-commits
