--- a/lib/DebugInfo/DWARF/DWARFDebugLine.cpp	Sat Feb 17 09:57:20 2018 +0900
+++ b/lib/DebugInfo/DWARF/DWARFDebugLine.cpp	Wed Aug 14 16:55:33 2019 +0900
@@ -1,21 +1,23 @@
 //===- DWARFDebugLine.cpp -------------------------------------------------===//
 //
-//                     The LLVM Compiler Infrastructure
-//
-// This file is distributed under the University of Illinois Open Source
-// License. See LICENSE.TXT for details.
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 //
 //===----------------------------------------------------------------------===//
 
 #include "llvm/DebugInfo/DWARF/DWARFDebugLine.h"
+#include "llvm/ADT/Optional.h"
 #include "llvm/ADT/SmallString.h"
 #include "llvm/ADT/SmallVector.h"
 #include "llvm/ADT/StringRef.h"
 #include "llvm/BinaryFormat/Dwarf.h"
 #include "llvm/DebugInfo/DWARF/DWARFFormValue.h"
 #include "llvm/DebugInfo/DWARF/DWARFRelocMap.h"
+#include "llvm/Support/Errc.h"
 #include "llvm/Support/Format.h"
 #include "llvm/Support/Path.h"
+#include "llvm/Support/WithColor.h"
 #include "llvm/Support/raw_ostream.h"
 #include <algorithm>
 #include <cassert>
@@ -40,15 +42,57 @@
 
 } // end anonmyous namespace
 
+void DWARFDebugLine::ContentTypeTracker::trackContentType(
+    dwarf::LineNumberEntryFormat ContentType) {
+  switch (ContentType) {
+  case dwarf::DW_LNCT_timestamp:
+    HasModTime = true;
+    break;
+  case dwarf::DW_LNCT_size:
+    HasLength = true;
+    break;
+  case dwarf::DW_LNCT_MD5:
+    HasMD5 = true;
+    break;
+  case dwarf::DW_LNCT_LLVM_source:
+    HasSource = true;
+    break;
+  default:
+    // We only care about values we consider optional, and new values may be
+    // added in the vendor extension range, so we do not match exhaustively.
+    break;
+  }
+}
+
 DWARFDebugLine::Prologue::Prologue() { clear(); }
 
+bool DWARFDebugLine::Prologue::hasFileAtIndex(uint64_t FileIndex) const {
+  uint16_t DwarfVersion = getVersion();
+  assert(DwarfVersion != 0 &&
+         "line table prologue has no dwarf version information");
+  if (DwarfVersion >= 5)
+    return FileIndex < FileNames.size();
+  return FileIndex != 0 && FileIndex <= FileNames.size();
+}
+
+const llvm::DWARFDebugLine::FileNameEntry &
+DWARFDebugLine::Prologue::getFileNameEntry(uint64_t Index) const {
+  uint16_t DwarfVersion = getVersion();
+  assert(DwarfVersion != 0 &&
+         "line table prologue has no dwarf version information");
+  // In DWARF v5 the file names are 0-indexed.
+  if (DwarfVersion >= 5)
+    return FileNames[Index];
+  return FileNames[Index - 1];
+}
+
 void DWARFDebugLine::Prologue::clear() {
   TotalLength = PrologueLength = 0;
   SegSelectorSize = 0;
   MinInstLength = MaxOpsPerInst = DefaultIsStmt = LineBase = LineRange = 0;
   OpcodeBase = 0;
-  FormParams = DWARFFormParams({0, 0, DWARF32});
-  HasMD5 = false;
+  FormParams = dwarf::FormParams({0, 0, DWARF32});
+  ContentTypes = ContentTypeTracker();
   StandardOpcodeLengths.clear();
   IncludeDirectories.clear();
   FileNames.clear();
@@ -85,28 +129,26 @@
   }
 
   if (!FileNames.empty()) {
-    if (HasMD5)
-      OS << "                Dir  MD5 Checksum                     File Name\n"
-         << "                ---- -------------------------------- -----------"
-            "---------------\n";
-    else
-      OS << "                Dir  Mod Time   File Len   File Name\n"
-         << "                ---- ---------- ---------- -----------"
-            "----------------\n";
     // DWARF v5 starts file indexes at 0.
     uint32_t FileBase = getVersion() >= 5 ? 0 : 1;
     for (uint32_t I = 0; I != FileNames.size(); ++I) {
       const FileNameEntry &FileEntry = FileNames[I];
-      OS << format("file_names[%3u] %4" PRIu64 " ", I + FileBase,
-                   FileEntry.DirIdx);
-      if (HasMD5)
-        OS << FileEntry.Checksum.digest();
-      else
-        OS << format("0x%8.8" PRIx64 " 0x%8.8" PRIx64, FileEntry.ModTime,
-                     FileEntry.Length);
-      OS << ' ';
+      OS <<   format("file_names[%3u]:\n", I + FileBase);
+      OS <<          "           name: ";
       FileEntry.Name.dump(OS, DumpOptions);
-      OS << '\n';
+      OS << '\n'
+         <<   format("      dir_index: %" PRIu64 "\n", FileEntry.DirIdx);
+      if (ContentTypes.HasMD5)
+        OS <<        "   md5_checksum: " << FileEntry.Checksum.digest() << '\n';
+      if (ContentTypes.HasModTime)
+        OS << format("       mod_time: 0x%8.8" PRIx64 "\n", FileEntry.ModTime);
+      if (ContentTypes.HasLength)
+        OS << format("         length: 0x%8.8" PRIx64 "\n", FileEntry.Length);
+      if (ContentTypes.HasSource) {
+        OS <<        "         source: ";
+        FileEntry.Source.dump(OS, DumpOptions);
+        OS << '\n';
+      }
     }
   }
 }
@@ -114,15 +156,16 @@
 // Parse v2-v4 directory and file tables.
 static void
 parseV2DirFileTables(const DWARFDataExtractor &DebugLineData,
-                     uint32_t *OffsetPtr, uint64_t EndPrologueOffset,
+                     uint64_t *OffsetPtr, uint64_t EndPrologueOffset,
+                     DWARFDebugLine::ContentTypeTracker &ContentTypes,
                      std::vector<DWARFFormValue> &IncludeDirectories,
                      std::vector<DWARFDebugLine::FileNameEntry> &FileNames) {
   while (*OffsetPtr < EndPrologueOffset) {
     StringRef S = DebugLineData.getCStrRef(OffsetPtr);
     if (S.empty())
       break;
-    DWARFFormValue Dir(dwarf::DW_FORM_string);
-    Dir.setPValue(S.data());
+    DWARFFormValue Dir =
+        DWARFFormValue::createFromPValue(dwarf::DW_FORM_string, S.data());
     IncludeDirectories.push_back(Dir);
   }
 
@@ -131,93 +174,130 @@
     if (Name.empty())
       break;
     DWARFDebugLine::FileNameEntry FileEntry;
-    FileEntry.Name.setForm(dwarf::DW_FORM_string);
-    FileEntry.Name.setPValue(Name.data());
+    FileEntry.Name =
+        DWARFFormValue::createFromPValue(dwarf::DW_FORM_string, Name.data());
     FileEntry.DirIdx = DebugLineData.getULEB128(OffsetPtr);
     FileEntry.ModTime = DebugLineData.getULEB128(OffsetPtr);
     FileEntry.Length = DebugLineData.getULEB128(OffsetPtr);
     FileNames.push_back(FileEntry);
   }
+
+  ContentTypes.HasModTime = true;
+  ContentTypes.HasLength = true;
 }
 
 // Parse v5 directory/file entry content descriptions.
-// Returns the descriptors, or an empty vector if we did not find a path or
-// ran off the end of the prologue.
-static ContentDescriptors
-parseV5EntryFormat(const DWARFDataExtractor &DebugLineData, uint32_t *OffsetPtr,
-                   uint64_t EndPrologueOffset, bool *HasMD5) {
+// Returns the descriptors, or an error if we did not find a path or ran off
+// the end of the prologue.
+static llvm::Expected<ContentDescriptors>
+parseV5EntryFormat(const DWARFDataExtractor &DebugLineData, uint64_t *OffsetPtr,
+                   uint64_t EndPrologueOffset,
+                   DWARFDebugLine::ContentTypeTracker *ContentTypes) {
   ContentDescriptors Descriptors;
   int FormatCount = DebugLineData.getU8(OffsetPtr);
   bool HasPath = false;
   for (int I = 0; I != FormatCount; ++I) {
     if (*OffsetPtr >= EndPrologueOffset)
-      return ContentDescriptors();
+      return createStringError(
+          errc::invalid_argument,
+          "failed to parse entry content descriptions at offset "
+          "0x%8.8" PRIx64
+          " because offset extends beyond the prologue end at offset "
+          "0x%8.8" PRIx64,
+          *OffsetPtr, EndPrologueOffset);
     ContentDescriptor Descriptor;
     Descriptor.Type =
       dwarf::LineNumberEntryFormat(DebugLineData.getULEB128(OffsetPtr));
     Descriptor.Form = dwarf::Form(DebugLineData.getULEB128(OffsetPtr));
     if (Descriptor.Type == dwarf::DW_LNCT_path)
       HasPath = true;
-    else if (Descriptor.Type == dwarf::DW_LNCT_MD5 && HasMD5)
-      *HasMD5 = true;
+    if (ContentTypes)
+      ContentTypes->trackContentType(Descriptor.Type);
     Descriptors.push_back(Descriptor);
   }
-  return HasPath ? Descriptors : ContentDescriptors();
+
+  if (!HasPath)
+    return createStringError(errc::invalid_argument,
+                             "failed to parse entry content descriptions"
+                             " because no path was found");
+  return Descriptors;
 }
 
-static bool
+static Error
 parseV5DirFileTables(const DWARFDataExtractor &DebugLineData,
-                     uint32_t *OffsetPtr, uint64_t EndPrologueOffset,
-                     const DWARFFormParams &FormParams, const DWARFContext &Ctx,
-                     const DWARFUnit *U, bool &HasMD5,
+                     uint64_t *OffsetPtr, uint64_t EndPrologueOffset,
+                     const dwarf::FormParams &FormParams,
+                     const DWARFContext &Ctx, const DWARFUnit *U,
+                     DWARFDebugLine::ContentTypeTracker &ContentTypes,
                      std::vector<DWARFFormValue> &IncludeDirectories,
                      std::vector<DWARFDebugLine::FileNameEntry> &FileNames) {
   // Get the directory entry description.
-  ContentDescriptors DirDescriptors =
+  llvm::Expected<ContentDescriptors> DirDescriptors =
       parseV5EntryFormat(DebugLineData, OffsetPtr, EndPrologueOffset, nullptr);
-  if (DirDescriptors.empty())
-    return false;
+  if (!DirDescriptors)
+    return DirDescriptors.takeError();
 
   // Get the directory entries, according to the format described above.
   int DirEntryCount = DebugLineData.getU8(OffsetPtr);
   for (int I = 0; I != DirEntryCount; ++I) {
     if (*OffsetPtr >= EndPrologueOffset)
-      return false;
-    for (auto Descriptor : DirDescriptors) {
+      return createStringError(
+          errc::invalid_argument,
+          "failed to parse directory entry at offset "
+          "0x%8.8" PRIx64
+          " because offset extends beyond the prologue end at offset "
+          "0x%8.8" PRIx64,
+          *OffsetPtr, EndPrologueOffset);
+    for (auto Descriptor : *DirDescriptors) {
       DWARFFormValue Value(Descriptor.Form);
       switch (Descriptor.Type) {
       case DW_LNCT_path:
         if (!Value.extractValue(DebugLineData, OffsetPtr, FormParams, &Ctx, U))
-          return false;
+          return createStringError(errc::invalid_argument,
+                                   "failed to parse directory entry because "
+                                   "extracting the form value failed.");
         IncludeDirectories.push_back(Value);
         break;
       default:
         if (!Value.skipValue(DebugLineData, OffsetPtr, FormParams))
-          return false;
+          return createStringError(errc::invalid_argument,
+                                   "failed to parse directory entry because "
+                                   "skipping the form value failed.");
       }
     }
   }
 
   // Get the file entry description.
-  ContentDescriptors FileDescriptors =
-      parseV5EntryFormat(DebugLineData, OffsetPtr, EndPrologueOffset, &HasMD5);
-  if (FileDescriptors.empty())
-    return false;
+  llvm::Expected<ContentDescriptors> FileDescriptors = parseV5EntryFormat(
+      DebugLineData, OffsetPtr, EndPrologueOffset, &ContentTypes);
+  if (!FileDescriptors)
+    return FileDescriptors.takeError();
 
   // Get the file entries, according to the format described above.
   int FileEntryCount = DebugLineData.getU8(OffsetPtr);
   for (int I = 0; I != FileEntryCount; ++I) {
     if (*OffsetPtr >= EndPrologueOffset)
-      return false;
+      return createStringError(
+          errc::invalid_argument,
+          "failed to parse file entry at offset "
+          "0x%8.8" PRIx64
+          " because offset extends beyond the prologue end at offset "
+          "0x%8.8" PRIx64,
+          *OffsetPtr, EndPrologueOffset);
     DWARFDebugLine::FileNameEntry FileEntry;
-    for (auto Descriptor : FileDescriptors) {
+    for (auto Descriptor : *FileDescriptors) {
       DWARFFormValue Value(Descriptor.Form);
       if (!Value.extractValue(DebugLineData, OffsetPtr, FormParams, &Ctx, U))
-        return false;
+        return createStringError(errc::invalid_argument,
+                                 "failed to parse file entry because "
+                                 "extracting the form value failed.");
       switch (Descriptor.Type) {
       case DW_LNCT_path:
         FileEntry.Name = Value;
         break;
+      case DW_LNCT_LLVM_source:
+        FileEntry.Source = Value;
+        break;
       case DW_LNCT_directory_index:
         FileEntry.DirIdx = Value.getAsUnsignedConstant().getValue();
         break;
@@ -228,7 +308,10 @@
         FileEntry.Length = Value.getAsUnsignedConstant().getValue();
         break;
       case DW_LNCT_MD5:
-        assert(Value.getAsBlock().getValue().size() == 16);
+        if (!Value.getAsBlock() || Value.getAsBlock().getValue().size() != 16)
+          return createStringError(
+              errc::invalid_argument,
+              "failed to parse file entry because the MD5 hash is invalid");
         std::uninitialized_copy_n(Value.getAsBlock().getValue().begin(), 16,
                                   FileEntry.Checksum.Bytes.begin());
         break;
@@ -238,26 +321,32 @@
     }
     FileNames.push_back(FileEntry);
   }
-  return true;
+  return Error::success();
 }
 
-bool DWARFDebugLine::Prologue::parse(const DWARFDataExtractor &DebugLineData,
-                                     uint32_t *OffsetPtr,
-                                     const DWARFContext &Ctx,
-                                     const DWARFUnit *U) {
+Error DWARFDebugLine::Prologue::parse(const DWARFDataExtractor &DebugLineData,
+                                      uint64_t *OffsetPtr,
+                                      const DWARFContext &Ctx,
+                                      const DWARFUnit *U) {
   const uint64_t PrologueOffset = *OffsetPtr;
 
   clear();
-  TotalLength = DebugLineData.getU32(OffsetPtr);
-  if (TotalLength == UINT32_MAX) {
+  TotalLength = DebugLineData.getRelocatedValue(4, OffsetPtr);
+  if (TotalLength == dwarf::DW_LENGTH_DWARF64) {
     FormParams.Format = dwarf::DWARF64;
     TotalLength = DebugLineData.getU64(OffsetPtr);
-  } else if (TotalLength >= 0xffffff00) {
-    return false;
+  } else if (TotalLength >= dwarf::DW_LENGTH_lo_reserved) {
+    return createStringError(errc::invalid_argument,
+        "parsing line table prologue at offset 0x%8.8" PRIx64
+        " unsupported reserved unit length found of value 0x%8.8" PRIx64,
+        PrologueOffset, TotalLength);
   }
   FormParams.Version = DebugLineData.getU16(OffsetPtr);
   if (getVersion() < 2)
-    return false;
+    return createStringError(errc::not_supported,
+                       "parsing line table prologue at offset 0x%8.8" PRIx64
+                       " found unsupported version 0x%2.2" PRIx16,
+                       PrologueOffset, getVersion());
 
   if (getVersion() >= 5) {
     FormParams.AddrSize = DebugLineData.getU8(OffsetPtr);
@@ -267,7 +356,8 @@
     SegSelectorSize = DebugLineData.getU8(OffsetPtr);
   }
 
-  PrologueLength = DebugLineData.getUnsigned(OffsetPtr, sizeofPrologueLength());
+  PrologueLength =
+      DebugLineData.getRelocatedValue(sizeofPrologueLength(), OffsetPtr);
   const uint64_t EndPrologueOffset = PrologueLength + *OffsetPtr;
   MinInstLength = DebugLineData.getU8(OffsetPtr);
   if (getVersion() >= 4)
@@ -284,40 +374,43 @@
   }
 
   if (getVersion() >= 5) {
-    if (!parseV5DirFileTables(DebugLineData, OffsetPtr, EndPrologueOffset,
-                              FormParams, Ctx, U, HasMD5, IncludeDirectories,
-                              FileNames)) {
-      fprintf(stderr,
-              "warning: parsing line table prologue at 0x%8.8" PRIx64
+    if (Error e = parseV5DirFileTables(
+            DebugLineData, OffsetPtr, EndPrologueOffset, FormParams, Ctx, U,
+            ContentTypes, IncludeDirectories, FileNames)) {
+      return joinErrors(
+          createStringError(
+              errc::invalid_argument,
+              "parsing line table prologue at 0x%8.8" PRIx64
               " found an invalid directory or file table description at"
-              " 0x%8.8" PRIx64 "\n", PrologueOffset, (uint64_t)*OffsetPtr);
-      return false;
+              " 0x%8.8" PRIx64,
+              PrologueOffset, *OffsetPtr),
+          std::move(e));
     }
   } else
     parseV2DirFileTables(DebugLineData, OffsetPtr, EndPrologueOffset,
-                         IncludeDirectories, FileNames);
+                         ContentTypes, IncludeDirectories, FileNames);
 
-  if (*OffsetPtr != EndPrologueOffset) {
-    fprintf(stderr,
-            "warning: parsing line table prologue at 0x%8.8" PRIx64
-            " should have ended at 0x%8.8" PRIx64
-            " but it ended at 0x%8.8" PRIx64 "\n",
-            PrologueOffset, EndPrologueOffset, (uint64_t)*OffsetPtr);
-    return false;
-  }
-  return true;
+  if (*OffsetPtr != EndPrologueOffset)
+    return createStringError(errc::invalid_argument,
+                       "parsing line table prologue at 0x%8.8" PRIx64
+                       " should have ended at 0x%8.8" PRIx64
+                       " but it ended at 0x%8.8" PRIx64,
+                       PrologueOffset, EndPrologueOffset, *OffsetPtr);
+  return Error::success();
 }
 
 DWARFDebugLine::Row::Row(bool DefaultIsStmt) { reset(DefaultIsStmt); }
 
 void DWARFDebugLine::Row::postAppend() {
+  Discriminator = 0;
   BasicBlock = false;
   PrologueEnd = false;
   EpilogueBegin = false;
 }
 
 void DWARFDebugLine::Row::reset(bool DefaultIsStmt) {
-  Address = 0;
+  Address.Address = 0;
+  Address.SectionIndex = object::SectionedAddress::UndefSection;
   Line = 1;
   Column = 0;
   File = 1;
@@ -337,7 +430,7 @@
 }
 
 void DWARFDebugLine::Row::dump(raw_ostream &OS) const {
-  OS << format("0x%16.16" PRIx64 " %6u %6u", Address, Line, Column)
+  OS << format("0x%16.16" PRIx64 " %6u %6u", Address.Address, Line, Column)
      << format(" %6u %3u %13u ", File, Isa, Discriminator)
      << (IsStmt ? " is_stmt" : "") << (BasicBlock ? " basic_block" : "")
      << (PrologueEnd ? " prologue_end" : "")
@@ -350,6 +443,7 @@
 void DWARFDebugLine::Sequence::reset() {
   LowPC = 0;
   HighPC = 0;
+  SectionIndex = object::SectionedAddress::UndefSection;
   FirstRowIndex = 0;
   LastRowIndex = 0;
   Empty = true;
@@ -386,19 +480,20 @@
   Sequence.reset();
 }
 
-void DWARFDebugLine::ParsingState::appendRowToMatrix(uint32_t Offset) {
+void DWARFDebugLine::ParsingState::appendRowToMatrix() {
+  unsigned RowNumber = LineTable->Rows.size();
   if (Sequence.Empty) {
     // Record the beginning of instruction sequence.
     Sequence.Empty = false;
-    Sequence.LowPC = Row.Address;
+    Sequence.LowPC = Row.Address.Address;
     Sequence.FirstRowIndex = RowNumber;
   }
-  ++RowNumber;
   LineTable->appendRow(Row);
   if (Row.EndSequence) {
     // Record the end of instruction sequence.
-    Sequence.HighPC = Row.Address;
-    Sequence.LastRowIndex = RowNumber;
+    Sequence.HighPC = Row.Address.Address;
+    Sequence.LastRowIndex = RowNumber + 1;
+    Sequence.SectionIndex = Row.Address.SectionIndex;
     if (Sequence.isValid())
       LineTable->appendSequence(Sequence);
     Sequence.reset();
@@ -407,40 +502,42 @@
 }
 
 const DWARFDebugLine::LineTable *
-DWARFDebugLine::getLineTable(uint32_t Offset) const {
+DWARFDebugLine::getLineTable(uint64_t Offset) const {
   LineTableConstIter Pos = LineTableMap.find(Offset);
   if (Pos != LineTableMap.end())
     return &Pos->second;
   return nullptr;
 }
 
-const DWARFDebugLine::LineTable *
-DWARFDebugLine::getOrParseLineTable(DWARFDataExtractor &DebugLineData,
-                                    uint32_t Offset, const DWARFContext &Ctx,
-                                    const DWARFUnit *U) {
+Expected<const DWARFDebugLine::LineTable *> DWARFDebugLine::getOrParseLineTable(
+    DWARFDataExtractor &DebugLineData, uint64_t Offset, const DWARFContext &Ctx,
+    const DWARFUnit *U, std::function<void(Error)> RecoverableErrorCallback) {
+  if (!DebugLineData.isValidOffset(Offset))
+    return createStringError(errc::invalid_argument, "offset 0x%8.8" PRIx64
+                       " is not a valid debug line section offset",
+                       Offset);
+
   std::pair<LineTableIter, bool> Pos =
       LineTableMap.insert(LineTableMapTy::value_type(Offset, LineTable()));
   LineTable *LT = &Pos.first->second;
   if (Pos.second) {
-    if (!LT->parse(DebugLineData, &Offset, Ctx, U))
-      return nullptr;
+    if (Error Err =
+            LT->parse(DebugLineData, &Offset, Ctx, U, RecoverableErrorCallback))
+      return std::move(Err);
+    return LT;
   }
   return LT;
 }
 
-bool DWARFDebugLine::LineTable::parse(DWARFDataExtractor &DebugLineData,
-                                      uint32_t *OffsetPtr,
-                                      const DWARFContext &Ctx,
-                                      const DWARFUnit *U, raw_ostream *OS) {
-  const uint32_t DebugLineOffset = *OffsetPtr;
+Error DWARFDebugLine::LineTable::parse(
+    DWARFDataExtractor &DebugLineData, uint64_t *OffsetPtr,
+    const DWARFContext &Ctx, const DWARFUnit *U,
+    std::function<void(Error)> RecoverableErrorCallback, raw_ostream *OS) {
+  const uint64_t DebugLineOffset = *OffsetPtr;
 
   clear();
 
-  if (!Prologue.parse(DebugLineData, OffsetPtr, Ctx, U)) {
-    // Restore our offset and return false to indicate failure!
-    *OffsetPtr = DebugLineOffset;
-    return false;
-  }
+  Error PrologueErr = Prologue.parse(DebugLineData, OffsetPtr, Ctx, U);
 
   if (OS) {
     // The presence of OS signals verbose dumping.
@@ -449,7 +546,10 @@
     Prologue.dump(*OS, DumpOptions);
   }
 
-  const uint32_t EndOffset =
+  if (PrologueErr)
+    return PrologueErr;
+
+  const uint64_t EndOffset =
       DebugLineOffset + Prologue.TotalLength + Prologue.sizeofTotalLength();
 
   // See if we should tell the data extractor the address size.
@@ -463,7 +563,7 @@
 
   while (*OffsetPtr < EndOffset) {
     if (OS)
-      *OS << format("0x%08.08" PRIx32 ": ", *OffsetPtr);
+      *OS << format("0x%08.08" PRIx64 ": ", *OffsetPtr);
 
     uint8_t Opcode = DebugLineData.getU8(OffsetPtr);
 
@@ -474,7 +574,7 @@
       // Extended Opcodes always start with a zero opcode followed by
       // a uleb128 length so you can skip ones you don't know about
       uint64_t Len = DebugLineData.getULEB128(OffsetPtr);
-      uint32_t ExtOffset = *OffsetPtr;
+      uint64_t ExtOffset = *OffsetPtr;
 
       // Tolerate zero-length; assume length is correct and soldier on.
       if (Len == 0) {
@@ -496,7 +596,7 @@
         // address is that of the byte after the last target machine instruction
         // of the sequence.
         State.Row.EndSequence = true;
-        State.appendRowToMatrix(*OffsetPtr);
+        State.appendRowToMatrix();
         if (OS) {
           *OS << "\n";
           OS->indent(12);
@@ -517,11 +617,17 @@
         // from the size of the operand.
         if (DebugLineData.getAddressSize() == 0)
           DebugLineData.setAddressSize(Len - 1);
-        else
-          assert(DebugLineData.getAddressSize() == Len - 1);
-        State.Row.Address = DebugLineData.getRelocatedAddress(OffsetPtr);
+        else if (DebugLineData.getAddressSize() != Len - 1) {
+          return createStringError(errc::invalid_argument,
+                             "mismatching address size at offset 0x%8.8" PRIx64
+                             " expected 0x%2.2" PRIx8 " found 0x%2.2" PRIx64,
+                             ExtOffset, DebugLineData.getAddressSize(),
+                             Len - 1);
+        }
+        State.Row.Address.Address = DebugLineData.getRelocatedAddress(
+            OffsetPtr, &State.Row.Address.SectionIndex);
         if (OS)
-          *OS << format(" (0x%16.16" PRIx64 ")", State.Row.Address);
+          *OS << format(" (0x%16.16" PRIx64 ")", State.Row.Address.Address);
         break;
 
       case DW_LNE_define_file:
@@ -548,8 +654,8 @@
         {
           FileNameEntry FileEntry;
           const char *Name = DebugLineData.getCStr(OffsetPtr);
-          FileEntry.Name.setForm(dwarf::DW_FORM_string);
-          FileEntry.Name.setPValue(Name);
+          FileEntry.Name =
+              DWARFFormValue::createFromPValue(dwarf::DW_FORM_string, Name);
           FileEntry.DirIdx = DebugLineData.getULEB128(OffsetPtr);
           FileEntry.ModTime = DebugLineData.getULEB128(OffsetPtr);
           FileEntry.Length = DebugLineData.getULEB128(OffsetPtr);
@@ -578,14 +684,11 @@
       }
       // Make sure the stated and parsed lengths are the same.
       // Otherwise we have an unparseable line-number program.
-      if (*OffsetPtr - ExtOffset != Len) {
-        fprintf(stderr, "Unexpected line op length at offset 0x%8.8" PRIx32
-                " expected 0x%2.2" PRIx64 " found 0x%2.2" PRIx32 "\n",
-                ExtOffset, Len, *OffsetPtr - ExtOffset);
-        // Skip the rest of the line-number program.
-        *OffsetPtr = EndOffset;
-        return false;
-      }
+      if (*OffsetPtr - ExtOffset != Len)
+        return createStringError(errc::illegal_byte_sequence,
+                           "unexpected line op length at offset 0x%8.8" PRIx64
+                           " expected 0x%2.2" PRIx64 " found 0x%2.2" PRIx64,
+                           ExtOffset, Len, *OffsetPtr - ExtOffset);
     } else if (Opcode < Prologue.OpcodeBase) {
       if (OS)
         *OS << LNStandardString(Opcode);
@@ -593,15 +696,14 @@
       // Standard Opcodes
       case DW_LNS_copy:
         // Takes no arguments. Append a row to the matrix using the
-        // current values of the state-machine registers. Then set
-        // the basic_block register to false.
-        State.appendRowToMatrix(*OffsetPtr);
+        // current values of the state-machine registers.
         if (OS) {
           *OS << "\n";
           OS->indent(12);
           State.Row.dump(*OS);
           *OS << "\n";
         }
+        State.appendRowToMatrix();
         break;
 
       case DW_LNS_advance_pc:
@@ -611,7 +713,7 @@
         {
           uint64_t AddrOffset =
               DebugLineData.getULEB128(OffsetPtr) * Prologue.MinInstLength;
-          State.Row.Address += AddrOffset;
+          State.Row.Address.Address += AddrOffset;
           if (OS)
             *OS << " (" << AddrOffset << ")";
         }
@@ -669,7 +771,7 @@
           uint8_t AdjustOpcode = 255 - Prologue.OpcodeBase;
           uint64_t AddrOffset =
               (AdjustOpcode / Prologue.LineRange) * Prologue.MinInstLength;
-          State.Row.Address += AddrOffset;
+          State.Row.Address.Address += AddrOffset;
           if (OS)
             *OS
                 << format(" (0x%16.16" PRIx64 ")", AddrOffset);
@@ -687,11 +789,11 @@
         // requires the use of DW_LNS_advance_pc. Such assemblers, however,
         // can use DW_LNS_fixed_advance_pc instead, sacrificing compression.
         {
-          uint16_t PCOffset = DebugLineData.getU16(OffsetPtr);
-          State.Row.Address += PCOffset;
+          uint16_t PCOffset = DebugLineData.getRelocatedValue(2, OffsetPtr);
+          State.Row.Address.Address += PCOffset;
           if (OS)
             *OS
-                << format(" (0x%16.16" PRIx64 ")", PCOffset);
+                << format(" (0x%4.4" PRIx16 ")", PCOffset);
         }
         break;
 
@@ -771,31 +873,29 @@
       int32_t LineOffset =
           Prologue.LineBase + (AdjustOpcode % Prologue.LineRange);
       State.Row.Line += LineOffset;
-      State.Row.Address += AddrOffset;
+      State.Row.Address.Address += AddrOffset;
 
       if (OS) {
-        *OS << "address += " << ((uint32_t)AdjustOpcode)
-            << ",  line += " << LineOffset << "\n";
+        *OS << "address += " << AddrOffset << ",  line += " << LineOffset
+            << "\n";
         OS->indent(12);
         State.Row.dump(*OS);
       }
 
-      State.appendRowToMatrix(*OffsetPtr);
-      // Reset discriminator to 0.
-      State.Row.Discriminator = 0;
+      State.appendRowToMatrix();
     }
     if(OS)
       *OS << "\n";
   }
 
-  if (!State.Sequence.Empty) {
-    fprintf(stderr, "warning: last sequence in debug line table is not"
-                    "terminated!\n");
-  }
+  if (!State.Sequence.Empty)
+    RecoverableErrorCallback(
+        createStringError(errc::illegal_byte_sequence,
+                    "last sequence in debug line table is not terminated!"));
 
   // Sort all sequences so that address lookup will work faster.
   if (!Sequences.empty()) {
-    std::sort(Sequences.begin(), Sequences.end(), Sequence::orderByLowPC);
+    llvm::sort(Sequences, Sequence::orderByHighPC);
     // Note: actually, instruction address ranges of sequences should not
     // overlap (in shared objects and executables). If they do, the address
     // lookup would still work, though, but result would be ambiguous.
@@ -804,77 +904,91 @@
     // rudimentary sequences for address ranges [0x0, 0xsomething).
   }
 
-  return EndOffset;
+  return Error::success();
 }
 
-uint32_t
-DWARFDebugLine::LineTable::findRowInSeq(const DWARFDebugLine::Sequence &Seq,
-                                        uint64_t Address) const {
+uint32_t DWARFDebugLine::LineTable::findRowInSeq(
+    const DWARFDebugLine::Sequence &Seq,
+    object::SectionedAddress Address) const {
   if (!Seq.containsPC(Address))
     return UnknownRowIndex;
-  // Search for instruction address in the rows describing the sequence.
-  // Rows are stored in a vector, so we may use arithmetical operations with
-  // iterators.
+  assert(Seq.SectionIndex == Address.SectionIndex);
+  // In some cases, e.g. first instruction in a function, the compiler generates
+  // two entries, both with the same address. We want the last one.
+  //
+  // In general we want a non-empty range: the last row whose address is less
+  // than or equal to Address. This can be computed as upper_bound - 1.
   DWARFDebugLine::Row Row;
   Row.Address = Address;
   RowIter FirstRow = Rows.begin() + Seq.FirstRowIndex;
   RowIter LastRow = Rows.begin() + Seq.LastRowIndex;
-  LineTable::RowIter RowPos = std::lower_bound(
-      FirstRow, LastRow, Row, DWARFDebugLine::Row::orderByAddress);
-  if (RowPos == LastRow) {
-    return Seq.LastRowIndex - 1;
-  }
-  uint32_t Index = Seq.FirstRowIndex + (RowPos - FirstRow);
-  if (RowPos->Address > Address) {
-    if (RowPos == FirstRow)
-      return UnknownRowIndex;
-    else
-      Index--;
-  }
-  return Index;
+  assert(FirstRow->Address.Address <= Row.Address.Address &&
+         Row.Address.Address < LastRow[-1].Address.Address);
+  RowIter RowPos = std::upper_bound(FirstRow + 1, LastRow - 1, Row,
+                                    DWARFDebugLine::Row::orderByAddress) -
+                   1;
+  assert(Seq.SectionIndex == RowPos->Address.SectionIndex);
+  return RowPos - Rows.begin();
 }
 
-uint32_t DWARFDebugLine::LineTable::lookupAddress(uint64_t Address) const {
-  if (Sequences.empty())
-    return UnknownRowIndex;
+uint32_t DWARFDebugLine::LineTable::lookupAddress(
+    object::SectionedAddress Address) const {
+
+  // Search for relocatable addresses
+  uint32_t Result = lookupAddressImpl(Address);
+
+  if (Result != UnknownRowIndex ||
+      Address.SectionIndex == object::SectionedAddress::UndefSection)
+    return Result;
+
+  // Search for absolute addresses
+  Address.SectionIndex = object::SectionedAddress::UndefSection;
+  return lookupAddressImpl(Address);
+}
+
+uint32_t DWARFDebugLine::LineTable::lookupAddressImpl(
+    object::SectionedAddress Address) const {
   // First, find an instruction sequence containing the given address.
   DWARFDebugLine::Sequence Sequence;
-  Sequence.LowPC = Address;
-  SequenceIter FirstSeq = Sequences.begin();
-  SequenceIter LastSeq = Sequences.end();
-  SequenceIter SeqPos = std::lower_bound(
-      FirstSeq, LastSeq, Sequence, DWARFDebugLine::Sequence::orderByLowPC);
-  DWARFDebugLine::Sequence FoundSeq;
-  if (SeqPos == LastSeq) {
-    FoundSeq = Sequences.back();
-  } else if (SeqPos->LowPC == Address) {
-    FoundSeq = *SeqPos;
-  } else {
-    if (SeqPos == FirstSeq)
-      return UnknownRowIndex;
-    FoundSeq = *(SeqPos - 1);
-  }
-  return findRowInSeq(FoundSeq, Address);
+  Sequence.SectionIndex = Address.SectionIndex;
+  Sequence.HighPC = Address.Address;
+  SequenceIter It = llvm::upper_bound(Sequences, Sequence,
+                                      DWARFDebugLine::Sequence::orderByHighPC);
+  if (It == Sequences.end() || It->SectionIndex != Address.SectionIndex)
+    return UnknownRowIndex;
+  return findRowInSeq(*It, Address);
 }
 
 bool DWARFDebugLine::LineTable::lookupAddressRange(
-    uint64_t Address, uint64_t Size, std::vector<uint32_t> &Result) const {
+    object::SectionedAddress Address, uint64_t Size,
+    std::vector<uint32_t> &Result) const {
+
+  // Search for relocatable addresses
+  if (lookupAddressRangeImpl(Address, Size, Result))
+    return true;
+
+  if (Address.SectionIndex == object::SectionedAddress::UndefSection)
+    return false;
+
+  // Search for absolute addresses
+  Address.SectionIndex = object::SectionedAddress::UndefSection;
+  return lookupAddressRangeImpl(Address, Size, Result);
+}
+
+bool DWARFDebugLine::LineTable::lookupAddressRangeImpl(
+    object::SectionedAddress Address, uint64_t Size,
+    std::vector<uint32_t> &Result) const {
   if (Sequences.empty())
     return false;
-  uint64_t EndAddr = Address + Size;
+  uint64_t EndAddr = Address.Address + Size;
   // First, find an instruction sequence containing the given address.
   DWARFDebugLine::Sequence Sequence;
-  Sequence.LowPC = Address;
-  SequenceIter FirstSeq = Sequences.begin();
+  Sequence.SectionIndex = Address.SectionIndex;
+  Sequence.HighPC = Address.Address;
   SequenceIter LastSeq = Sequences.end();
-  SequenceIter SeqPos = std::lower_bound(
-      FirstSeq, LastSeq, Sequence, DWARFDebugLine::Sequence::orderByLowPC);
-  if (SeqPos == LastSeq || SeqPos->LowPC != Address) {
-    if (SeqPos == FirstSeq)
-      return false;
-    SeqPos--;
-  }
-  if (!SeqPos->containsPC(Address))
+  SequenceIter SeqPos = llvm::upper_bound(
+      Sequences, Sequence, DWARFDebugLine::Sequence::orderByHighPC);
+  if (SeqPos == LastSeq || !SeqPos->containsPC(Address))
     return false;
 
   SequenceIter StartPos = SeqPos;
@@ -891,7 +1005,8 @@
       FirstRowIndex = findRowInSeq(CurSeq, Address);
 
     // Figure out the last row in the range.
-    uint32_t LastRowIndex = findRowInSeq(CurSeq, EndAddr - 1);
+    uint32_t LastRowIndex =
+        findRowInSeq(CurSeq, {EndAddr - 1, Address.SectionIndex});
     if (LastRowIndex == UnknownRowIndex)
       LastRowIndex = CurSeq.LastRowIndex - 1;
 
@@ -908,40 +1023,55 @@
   return true;
 }
 
-bool DWARFDebugLine::LineTable::hasFileAtIndex(uint64_t FileIndex) const {
-  return FileIndex != 0 && FileIndex <= Prologue.FileNames.size();
+Optional<StringRef> DWARFDebugLine::LineTable::getSourceByIndex(uint64_t FileIndex,
+                                                                FileLineInfoKind Kind) const {
+  if (Kind == FileLineInfoKind::None || !Prologue.hasFileAtIndex(FileIndex))
+    return None;
+  const FileNameEntry &Entry = Prologue.getFileNameEntry(FileIndex);
+  if (Optional<const char *> source = Entry.Source.getAsCString())
+    return StringRef(*source);
+  return None;
 }
 
-bool DWARFDebugLine::LineTable::getFileNameByIndex(uint64_t FileIndex,
-                                                   const char *CompDir,
-                                                   FileLineInfoKind Kind,
-                                                   std::string &Result) const {
+static bool isPathAbsoluteOnWindowsOrPosix(const Twine &Path) {
+  // Debug info can contain paths from any OS, not necessarily
+  // an OS we're currently running on. Moreover different compilation units can
+  // be compiled on different operating systems and linked together later.
+  return sys::path::is_absolute(Path, sys::path::Style::posix) ||
+         sys::path::is_absolute(Path, sys::path::Style::windows);
+}
+
+bool DWARFDebugLine::Prologue::getFileNameByIndex(uint64_t FileIndex,
+                                                  StringRef CompDir,
+                                                  FileLineInfoKind Kind,
+                                                  std::string &Result) const {
   if (Kind == FileLineInfoKind::None || !hasFileAtIndex(FileIndex))
     return false;
-  const FileNameEntry &Entry = Prologue.FileNames[FileIndex - 1];
+  const FileNameEntry &Entry = getFileNameEntry(FileIndex);
   StringRef FileName = Entry.Name.getAsCString().getValue();
   if (Kind != FileLineInfoKind::AbsoluteFilePath ||
-      sys::path::is_absolute(FileName)) {
+      isPathAbsoluteOnWindowsOrPosix(FileName)) {
     Result = FileName;
     return true;
   }
 
   SmallString<16> FilePath;
-  uint64_t IncludeDirIndex = Entry.DirIdx;
   StringRef IncludeDir;
   // Be defensive about the contents of Entry.
-  if (IncludeDirIndex > 0 &&
-      IncludeDirIndex <= Prologue.IncludeDirectories.size())
-    IncludeDir = Prologue.IncludeDirectories[IncludeDirIndex - 1]
-                     .getAsCString()
-                     .getValue();
+  if (getVersion() >= 5) {
+    if (Entry.DirIdx < IncludeDirectories.size())
+      IncludeDir = IncludeDirectories[Entry.DirIdx].getAsCString().getValue();
+  } else {
+    if (0 < Entry.DirIdx && Entry.DirIdx <= IncludeDirectories.size())
+      IncludeDir =
+          IncludeDirectories[Entry.DirIdx - 1].getAsCString().getValue();
 
-  // We may still need to append compilation directory of compile unit.
-  // We know that FileName is not absolute, the only way to have an
-  // absolute path at this point would be if IncludeDir is absolute.
-  if (CompDir && Kind == FileLineInfoKind::AbsoluteFilePath &&
-      sys::path::is_relative(IncludeDir))
-    sys::path::append(FilePath, CompDir);
+    // We may still need to append compilation directory of compile unit.
+    // We know that FileName is not absolute, the only way to have an
+    // absolute path at this point would be if IncludeDir is absolute.
+    if (!CompDir.empty() && !isPathAbsoluteOnWindowsOrPosix(IncludeDir))
+      sys::path::append(FilePath, CompDir);
+  }
 
   // sys::path::append skips empty strings.
   sys::path::append(FilePath, IncludeDir, FileName);
@@ -950,8 +1080,8 @@
 }
 
 bool DWARFDebugLine::LineTable::getFileLineInfoForAddress(
-    uint64_t Address, const char *CompDir, FileLineInfoKind Kind,
-    DILineInfo &Result) const {
+    object::SectionedAddress Address, const char *CompDir,
+    FileLineInfoKind Kind, DILineInfo &Result) const {
   // Get the index of row we're looking for in the line table.
   uint32_t RowIndex = lookupAddress(Address);
   if (RowIndex == -1U)
@@ -963,5 +1093,91 @@
   Result.Line = Row.Line;
   Result.Column = Row.Column;
   Result.Discriminator = Row.Discriminator;
+  Result.Source = getSourceByIndex(Row.File, Kind);
   return true;
 }
+
+// We want to supply the Unit associated with a .debug_line[.dwo] table when
+// we dump it, if possible, but still dump the table even if there isn't a Unit.
+// Therefore, collect up handles on all the Units that point into the
+// line-table section.
+static DWARFDebugLine::SectionParser::LineToUnitMap
+buildLineToUnitMap(DWARFDebugLine::SectionParser::cu_range CUs,
+                   DWARFDebugLine::SectionParser::tu_range TUs) {
+  DWARFDebugLine::SectionParser::LineToUnitMap LineToUnit;
+  for (const auto &CU : CUs)
+    if (auto CUDIE = CU->getUnitDIE())
+      if (auto StmtOffset = toSectionOffset(CUDIE.find(DW_AT_stmt_list)))
+        LineToUnit.insert(std::make_pair(*StmtOffset, &*CU));
+  for (const auto &TU : TUs)
+    if (auto TUDIE = TU->getUnitDIE())
+      if (auto StmtOffset = toSectionOffset(TUDIE.find(DW_AT_stmt_list)))
+        LineToUnit.insert(std::make_pair(*StmtOffset, &*TU));
+  return LineToUnit;
+}
+
+DWARFDebugLine::SectionParser::SectionParser(DWARFDataExtractor &Data,
+                                             const DWARFContext &C,
+                                             cu_range CUs, tu_range TUs)
+    : DebugLineData(Data), Context(C) {
+  LineToUnit = buildLineToUnitMap(CUs, TUs);
+  if (!DebugLineData.isValidOffset(Offset))
+    Done = true;
+}
+
+bool DWARFDebugLine::Prologue::totalLengthIsValid() const {
+  return TotalLength == dwarf::DW_LENGTH_DWARF64 ||
+         TotalLength < dwarf::DW_LENGTH_lo_reserved;
+}
+
+DWARFDebugLine::LineTable DWARFDebugLine::SectionParser::parseNext(
+    function_ref<void(Error)> RecoverableErrorCallback,
+    function_ref<void(Error)> UnrecoverableErrorCallback, raw_ostream *OS) {
+  assert(DebugLineData.isValidOffset(Offset) &&
+         "parsing should have terminated");
+  DWARFUnit *U = prepareToParse(Offset);
+  uint64_t OldOffset = Offset;
+  LineTable LT;
+  if (Error Err = LT.parse(DebugLineData, &Offset, Context, U,
+                           RecoverableErrorCallback, OS))
+    UnrecoverableErrorCallback(std::move(Err));
+  moveToNextTable(OldOffset, LT.Prologue);
+  return LT;
+}
+
+void DWARFDebugLine::SectionParser::skip(
+    function_ref<void(Error)> ErrorCallback) {
+  assert(DebugLineData.isValidOffset(Offset) &&
+         "parsing should have terminated");
+  DWARFUnit *U = prepareToParse(Offset);
+  uint64_t OldOffset = Offset;
+  LineTable LT;
+  if (Error Err = LT.Prologue.parse(DebugLineData, &Offset, Context, U))
+    ErrorCallback(std::move(Err));
+  moveToNextTable(OldOffset, LT.Prologue);
+}
+
+DWARFUnit *DWARFDebugLine::SectionParser::prepareToParse(uint64_t Offset) {
+  DWARFUnit *U = nullptr;
+  auto It = LineToUnit.find(Offset);
+  if (It != LineToUnit.end())
+    U = It->second;
+  DebugLineData.setAddressSize(U ? U->getAddressByteSize() : 0);
+  return U;
+}
+
+void DWARFDebugLine::SectionParser::moveToNextTable(uint64_t OldOffset,
+                                                    const Prologue &P) {
+  // If the length field is not valid, we don't know where the next table is, so
+  // cannot continue to parse. Mark the parser as done, and leave the Offset
+  // value as it currently is. This will be the end of the bad length field.
+  if (!P.totalLengthIsValid()) {
+    Done = true;
+    return;
+  }
+
+  Offset = OldOffset + P.TotalLength + P.sizeofTotalLength();
+  if (!DebugLineData.isValidOffset(Offset)) {
+    Done = true;
+  }
+}