Import prebuilt clang toolchain for linux.
diff --git a/linux-x64/clang/include/llvm/DebugInfo/DWARF/DWARFUnit.h b/linux-x64/clang/include/llvm/DebugInfo/DWARF/DWARFUnit.h
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+++ b/linux-x64/clang/include/llvm/DebugInfo/DWARF/DWARFUnit.h
@@ -0,0 +1,488 @@
+//===- DWARFUnit.h ----------------------------------------------*- C++ -*-===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_DEBUGINFO_DWARF_DWARFUNIT_H
+#define LLVM_DEBUGINFO_DWARF_DWARFUNIT_H
+
+#include "llvm/ADT/Optional.h"
+#include "llvm/ADT/STLExtras.h"
+#include "llvm/ADT/SmallVector.h"
+#include "llvm/ADT/StringRef.h"
+#include "llvm/ADT/iterator_range.h"
+#include "llvm/BinaryFormat/Dwarf.h"
+#include "llvm/DebugInfo/DWARF/DWARFDebugInfoEntry.h"
+#include "llvm/DebugInfo/DWARF/DWARFDebugRangeList.h"
+#include "llvm/DebugInfo/DWARF/DWARFDie.h"
+#include "llvm/DebugInfo/DWARF/DWARFFormValue.h"
+#include "llvm/DebugInfo/DWARF/DWARFRelocMap.h"
+#include "llvm/DebugInfo/DWARF/DWARFSection.h"
+#include "llvm/DebugInfo/DWARF/DWARFUnitIndex.h"
+#include "llvm/Support/DataExtractor.h"
+#include <algorithm>
+#include <cassert>
+#include <cstddef>
+#include <cstdint>
+#include <map>
+#include <memory>
+#include <utility>
+#include <vector>
+
+namespace llvm {
+
+class DWARFAbbreviationDeclarationSet;
+class DWARFContext;
+class DWARFDebugAbbrev;
+class DWARFUnit;
+
+/// Base class for all DWARFUnitSection classes. This provides the
+/// functionality common to all unit types.
+class DWARFUnitSectionBase {
+public:
+  /// Returns the Unit that contains the given section offset in the
+  /// same section this Unit originated from.
+  virtual DWARFUnit *getUnitForOffset(uint32_t Offset) const = 0;
+  virtual DWARFUnit *getUnitForIndexEntry(const DWARFUnitIndex::Entry &E) = 0;
+
+  void parse(DWARFContext &C, const DWARFSection &Section);
+  void parseDWO(DWARFContext &C, const DWARFSection &DWOSection,
+                bool Lazy = false);
+
+protected:
+  ~DWARFUnitSectionBase() = default;
+
+  virtual void parseImpl(DWARFContext &Context, const DWARFObject &Obj,
+                         const DWARFSection &Section,
+                         const DWARFDebugAbbrev *DA, const DWARFSection *RS,
+                         StringRef SS, const DWARFSection &SOS,
+                         const DWARFSection *AOS, const DWARFSection &LS,
+                         bool isLittleEndian, bool isDWO, bool Lazy) = 0;
+};
+
+const DWARFUnitIndex &getDWARFUnitIndex(DWARFContext &Context,
+                                        DWARFSectionKind Kind);
+
+/// Concrete instance of DWARFUnitSection, specialized for one Unit type.
+template<typename UnitType>
+class DWARFUnitSection final : public SmallVector<std::unique_ptr<UnitType>, 1>,
+                               public DWARFUnitSectionBase {
+  bool Parsed = false;
+  std::function<std::unique_ptr<UnitType>(uint32_t)> Parser;
+
+public:
+  using UnitVector = SmallVectorImpl<std::unique_ptr<UnitType>>;
+  using iterator = typename UnitVector::iterator;
+  using iterator_range = llvm::iterator_range<typename UnitVector::iterator>;
+
+  UnitType *getUnitForOffset(uint32_t Offset) const override {
+    auto *CU = std::upper_bound(
+        this->begin(), this->end(), Offset,
+        [](uint32_t LHS, const std::unique_ptr<UnitType> &RHS) {
+          return LHS < RHS->getNextUnitOffset();
+        });
+    if (CU != this->end() && (*CU)->getOffset() <= Offset)
+      return CU->get();
+    return nullptr;
+  }
+  UnitType *getUnitForIndexEntry(const DWARFUnitIndex::Entry &E) override {
+    const auto *CUOff = E.getOffset(DW_SECT_INFO);
+    if (!CUOff)
+      return nullptr;
+
+    auto Offset = CUOff->Offset;
+
+    auto *CU = std::upper_bound(
+        this->begin(), this->end(), CUOff->Offset,
+        [](uint32_t LHS, const std::unique_ptr<UnitType> &RHS) {
+          return LHS < RHS->getNextUnitOffset();
+        });
+    if (CU != this->end() && (*CU)->getOffset() <= Offset)
+      return CU->get();
+
+    if (!Parser)
+      return nullptr;
+
+    auto U = Parser(Offset);
+    if (!U)
+      U = nullptr;
+
+    auto *NewCU = U.get();
+    this->insert(CU, std::move(U));
+    return NewCU;
+  }
+
+private:
+  void parseImpl(DWARFContext &Context, const DWARFObject &Obj,
+                 const DWARFSection &Section, const DWARFDebugAbbrev *DA,
+                 const DWARFSection *RS, StringRef SS, const DWARFSection &SOS,
+                 const DWARFSection *AOS, const DWARFSection &LS, bool LE,
+                 bool IsDWO, bool Lazy) override {
+    if (Parsed)
+      return;
+    DWARFDataExtractor Data(Obj, Section, LE, 0);
+    if (!Parser) {
+      const DWARFUnitIndex *Index = nullptr;
+      if (IsDWO)
+        Index = &getDWARFUnitIndex(Context, UnitType::Section);
+      Parser = [=, &Context, &Section, &SOS,
+                &LS](uint32_t Offset) -> std::unique_ptr<UnitType> {
+        if (!Data.isValidOffset(Offset))
+          return nullptr;
+        auto U = llvm::make_unique<UnitType>(
+            Context, Section, DA, RS, SS, SOS, AOS, LS, LE, IsDWO, *this,
+            Index ? Index->getFromOffset(Offset) : nullptr);
+        if (!U->extract(Data, &Offset))
+          return nullptr;
+        return U;
+      };
+    }
+    if (Lazy)
+      return;
+    auto I = this->begin();
+    uint32_t Offset = 0;
+    while (Data.isValidOffset(Offset)) {
+      if (I != this->end() && (*I)->getOffset() == Offset) {
+        ++I;
+        continue;
+      }
+      auto U = Parser(Offset);
+      if (!U)
+        break;
+      Offset = U->getNextUnitOffset();
+      I = std::next(this->insert(I, std::move(U)));
+    }
+    Parsed = true;
+  }
+};
+
+/// Represents base address of the CU.
+struct BaseAddress {
+  uint64_t Address;
+  uint64_t SectionIndex;
+};
+
+/// Represents a unit's contribution to the string offsets table.
+struct StrOffsetsContributionDescriptor {
+  uint64_t Base = 0;
+  uint64_t Size = 0;
+  /// Format and version.
+  dwarf::FormParams FormParams = {0, 0, dwarf::DwarfFormat::DWARF32};
+
+  StrOffsetsContributionDescriptor(uint64_t Base, uint64_t Size,
+                                   uint8_t Version, dwarf::DwarfFormat Format)
+      : Base(Base), Size(Size), FormParams({Version, 0, Format}) {}
+
+  uint8_t getVersion() const { return FormParams.Version; }
+  dwarf::DwarfFormat getFormat() const { return FormParams.Format; }
+  uint8_t getDwarfOffsetByteSize() const {
+    return FormParams.getDwarfOffsetByteSize();
+  }
+  /// Determine whether a contribution to the string offsets table is
+  /// consistent with the relevant section size and that its length is
+  /// a multiple of the size of one of its entries.
+  Optional<StrOffsetsContributionDescriptor>
+  validateContributionSize(DWARFDataExtractor &DA);
+};
+
+class DWARFUnit {
+  DWARFContext &Context;
+  /// Section containing this DWARFUnit.
+  const DWARFSection &InfoSection;
+
+  const DWARFDebugAbbrev *Abbrev;
+  const DWARFSection *RangeSection;
+  uint32_t RangeSectionBase;
+  const DWARFSection &LineSection;
+  StringRef StringSection;
+  const DWARFSection &StringOffsetSection;
+  const DWARFSection *AddrOffsetSection;
+  uint32_t AddrOffsetSectionBase = 0;
+  bool isLittleEndian;
+  bool isDWO;
+  const DWARFUnitSectionBase &UnitSection;
+
+  // Version, address size, and DWARF format.
+  dwarf::FormParams FormParams;
+  /// Start, length, and DWARF format of the unit's contribution to the string
+  /// offsets table (DWARF v5).
+  Optional<StrOffsetsContributionDescriptor> StringOffsetsTableContribution;
+
+  uint32_t Offset;
+  uint32_t Length;
+  mutable const DWARFAbbreviationDeclarationSet *Abbrevs;
+  uint64_t AbbrOffset;
+  uint8_t UnitType;
+  llvm::Optional<BaseAddress> BaseAddr;
+  /// The compile unit debug information entry items.
+  std::vector<DWARFDebugInfoEntry> DieArray;
+
+  /// Map from range's start address to end address and corresponding DIE.
+  /// IntervalMap does not support range removal, as a result, we use the
+  /// std::map::upper_bound for address range lookup.
+  std::map<uint64_t, std::pair<uint64_t, DWARFDie>> AddrDieMap;
+
+  using die_iterator_range =
+      iterator_range<std::vector<DWARFDebugInfoEntry>::iterator>;
+
+  std::shared_ptr<DWARFUnit> DWO;
+
+  const DWARFUnitIndex::Entry *IndexEntry;
+
+  uint32_t getDIEIndex(const DWARFDebugInfoEntry *Die) {
+    auto First = DieArray.data();
+    assert(Die >= First && Die < First + DieArray.size());
+    return Die - First;
+  }
+
+protected:
+  virtual bool extractImpl(const DWARFDataExtractor &debug_info,
+                           uint32_t *offset_ptr);
+
+  /// Size in bytes of the unit header.
+  virtual uint32_t getHeaderSize() const { return getVersion() <= 4 ? 11 : 12; }
+
+  /// Find the unit's contribution to the string offsets table and determine its
+  /// length and form. The given offset is expected to be derived from the unit
+  /// DIE's DW_AT_str_offsets_base attribute.
+  Optional<StrOffsetsContributionDescriptor>
+  determineStringOffsetsTableContribution(DWARFDataExtractor &DA,
+                                          uint64_t Offset);
+
+  /// Find the unit's contribution to the string offsets table and determine its
+  /// length and form. The given offset is expected to be 0 in a dwo file or,
+  /// in a dwp file, the start of the unit's contribution to the string offsets
+  /// table section (as determined by the index table).
+  Optional<StrOffsetsContributionDescriptor>
+  determineStringOffsetsTableContributionDWO(DWARFDataExtractor &DA,
+                                             uint64_t Offset);
+
+public:
+  DWARFUnit(DWARFContext &Context, const DWARFSection &Section,
+            const DWARFDebugAbbrev *DA, const DWARFSection *RS, StringRef SS,
+            const DWARFSection &SOS, const DWARFSection *AOS,
+            const DWARFSection &LS, bool LE, bool IsDWO,
+            const DWARFUnitSectionBase &UnitSection,
+            const DWARFUnitIndex::Entry *IndexEntry = nullptr);
+
+  virtual ~DWARFUnit();
+
+  DWARFContext& getContext() const { return Context; }
+
+  const DWARFSection &getLineSection() const { return LineSection; }
+  StringRef getStringSection() const { return StringSection; }
+  const DWARFSection &getStringOffsetSection() const {
+    return StringOffsetSection;
+  }
+
+  void setAddrOffsetSection(const DWARFSection *AOS, uint32_t Base) {
+    AddrOffsetSection = AOS;
+    AddrOffsetSectionBase = Base;
+  }
+
+  /// Recursively update address to Die map.
+  void updateAddressDieMap(DWARFDie Die);
+
+  void setRangesSection(const DWARFSection *RS, uint32_t Base) {
+    RangeSection = RS;
+    RangeSectionBase = Base;
+  }
+
+  bool getAddrOffsetSectionItem(uint32_t Index, uint64_t &Result) const;
+  bool getStringOffsetSectionItem(uint32_t Index, uint64_t &Result) const;
+
+  DWARFDataExtractor getDebugInfoExtractor() const;
+
+  DataExtractor getStringExtractor() const {
+    return DataExtractor(StringSection, false, 0);
+  }
+
+  bool extract(const DWARFDataExtractor &debug_info, uint32_t *offset_ptr);
+
+  /// extractRangeList - extracts the range list referenced by this compile
+  /// unit from .debug_ranges section. Returns true on success.
+  /// Requires that compile unit is already extracted.
+  bool extractRangeList(uint32_t RangeListOffset,
+                        DWARFDebugRangeList &RangeList) const;
+  void clear();
+  uint32_t getOffset() const { return Offset; }
+  uint32_t getNextUnitOffset() const { return Offset + Length + 4; }
+  uint32_t getLength() const { return Length; }
+
+  const Optional<StrOffsetsContributionDescriptor> &
+  getStringOffsetsTableContribution() const {
+    return StringOffsetsTableContribution;
+  }
+  const dwarf::FormParams &getFormParams() const { return FormParams; }
+  uint16_t getVersion() const { return FormParams.Version; }
+  dwarf::DwarfFormat getFormat() const { return FormParams.Format; }
+  uint8_t getAddressByteSize() const { return FormParams.AddrSize; }
+  uint8_t getRefAddrByteSize() const { return FormParams.getRefAddrByteSize(); }
+  uint8_t getDwarfOffsetByteSize() const {
+    return FormParams.getDwarfOffsetByteSize();
+  }
+
+  uint8_t getDwarfStringOffsetsByteSize() const {
+    assert(StringOffsetsTableContribution);
+    return StringOffsetsTableContribution->getDwarfOffsetByteSize();
+  }
+
+  uint64_t getStringOffsetsBase() const {
+    assert(StringOffsetsTableContribution);
+    return StringOffsetsTableContribution->Base;
+  }
+
+  const DWARFAbbreviationDeclarationSet *getAbbreviations() const;
+
+  uint8_t getUnitType() const { return UnitType; }
+
+  static bool isMatchingUnitTypeAndTag(uint8_t UnitType, dwarf::Tag Tag) {
+    switch (UnitType) {
+    case dwarf::DW_UT_compile:
+      return Tag == dwarf::DW_TAG_compile_unit;
+    case dwarf::DW_UT_type:
+      return Tag == dwarf::DW_TAG_type_unit;
+    case dwarf::DW_UT_partial:
+      return Tag == dwarf::DW_TAG_partial_unit;
+    case dwarf::DW_UT_skeleton:
+      return Tag == dwarf::DW_TAG_skeleton_unit;
+    case dwarf::DW_UT_split_compile:
+    case dwarf::DW_UT_split_type:
+      return dwarf::isUnitType(Tag);
+    }
+    return false;
+  }
+
+  /// \brief Return the number of bytes for the header of a unit of
+  /// UnitType type.
+  ///
+  /// This function must be called with a valid unit type which in
+  /// DWARF5 is defined as one of the following six types.
+  static uint32_t getDWARF5HeaderSize(uint8_t UnitType) {
+    switch (UnitType) {
+    case dwarf::DW_UT_compile:
+    case dwarf::DW_UT_partial:
+      return 12;
+    case dwarf::DW_UT_skeleton:
+    case dwarf::DW_UT_split_compile:
+      return 20;
+    case dwarf::DW_UT_type:
+    case dwarf::DW_UT_split_type:
+      return 24;
+    }
+    llvm_unreachable("Invalid UnitType.");
+  }
+
+  llvm::Optional<BaseAddress> getBaseAddress() const { return BaseAddr; }
+
+  void setBaseAddress(BaseAddress BaseAddr) { this->BaseAddr = BaseAddr; }
+
+  DWARFDie getUnitDIE(bool ExtractUnitDIEOnly = true) {
+    extractDIEsIfNeeded(ExtractUnitDIEOnly);
+    if (DieArray.empty())
+      return DWARFDie();
+    return DWARFDie(this, &DieArray[0]);
+  }
+
+  const char *getCompilationDir();
+  Optional<uint64_t> getDWOId();
+
+  void collectAddressRanges(DWARFAddressRangesVector &CURanges);
+
+  /// Returns subprogram DIE with address range encompassing the provided
+  /// address. The pointer is alive as long as parsed compile unit DIEs are not
+  /// cleared.
+  DWARFDie getSubroutineForAddress(uint64_t Address);
+
+  /// getInlinedChainForAddress - fetches inlined chain for a given address.
+  /// Returns empty chain if there is no subprogram containing address. The
+  /// chain is valid as long as parsed compile unit DIEs are not cleared.
+  void getInlinedChainForAddress(uint64_t Address,
+                                 SmallVectorImpl<DWARFDie> &InlinedChain);
+
+  /// getUnitSection - Return the DWARFUnitSection containing this unit.
+  const DWARFUnitSectionBase &getUnitSection() const { return UnitSection; }
+
+  /// \brief Returns the number of DIEs in the unit. Parses the unit
+  /// if necessary.
+  unsigned getNumDIEs() {
+    extractDIEsIfNeeded(false);
+    return DieArray.size();
+  }
+
+  /// \brief Return the index of a DIE inside the unit's DIE vector.
+  ///
+  /// It is illegal to call this method with a DIE that hasn't be
+  /// created by this unit. In other word, it's illegal to call this
+  /// method on a DIE that isn't accessible by following
+  /// children/sibling links starting from this unit's getUnitDIE().
+  uint32_t getDIEIndex(const DWARFDie &D) {
+    return getDIEIndex(D.getDebugInfoEntry());
+  }
+
+  /// \brief Return the DIE object at the given index.
+  DWARFDie getDIEAtIndex(unsigned Index) {
+    assert(Index < DieArray.size());
+    return DWARFDie(this, &DieArray[Index]);
+  }
+
+  DWARFDie getParent(const DWARFDebugInfoEntry *Die);
+  DWARFDie getSibling(const DWARFDebugInfoEntry *Die);
+  DWARFDie getFirstChild(const DWARFDebugInfoEntry *Die);
+
+  /// \brief Return the DIE object for a given offset inside the
+  /// unit's DIE vector.
+  ///
+  /// The unit needs to have its DIEs extracted for this method to work.
+  DWARFDie getDIEForOffset(uint32_t Offset) {
+    extractDIEsIfNeeded(false);
+    assert(!DieArray.empty());
+    auto it = std::lower_bound(
+        DieArray.begin(), DieArray.end(), Offset,
+        [](const DWARFDebugInfoEntry &LHS, uint32_t Offset) {
+          return LHS.getOffset() < Offset;
+        });
+    if (it != DieArray.end() && it->getOffset() == Offset)
+      return DWARFDie(this, &*it);
+    return DWARFDie();
+  }
+
+  uint32_t getLineTableOffset() const {
+    if (IndexEntry)
+      if (const auto *Contrib = IndexEntry->getOffset(DW_SECT_LINE))
+        return Contrib->Offset;
+    return 0;
+  }
+
+  die_iterator_range dies() {
+    extractDIEsIfNeeded(false);
+    return die_iterator_range(DieArray.begin(), DieArray.end());
+  }
+
+private:
+  /// Size in bytes of the .debug_info data associated with this compile unit.
+  size_t getDebugInfoSize() const { return Length + 4 - getHeaderSize(); }
+
+  /// extractDIEsIfNeeded - Parses a compile unit and indexes its DIEs if it
+  /// hasn't already been done. Returns the number of DIEs parsed at this call.
+  size_t extractDIEsIfNeeded(bool CUDieOnly);
+
+  /// extractDIEsToVector - Appends all parsed DIEs to a vector.
+  void extractDIEsToVector(bool AppendCUDie, bool AppendNonCUDIEs,
+                           std::vector<DWARFDebugInfoEntry> &DIEs) const;
+
+  /// clearDIEs - Clear parsed DIEs to keep memory usage low.
+  void clearDIEs(bool KeepCUDie);
+
+  /// parseDWO - Parses .dwo file for current compile unit. Returns true if
+  /// it was actually constructed.
+  bool parseDWO();
+};
+
+} // end namespace llvm
+
+#endif // LLVM_DEBUGINFO_DWARF_DWARFUNIT_H