vendor/llvm/llvm-trunk-r375505vendor/llvm

11 files changed, 1121 insertions, 58 deletions

diff --git a/include/llvm/DebugInfo/GSYM/FileEntry.h b/include/llvm/DebugInfo/GSYM/FileEntry.h
index 228b4efa0656..49e7fc9c4291 100644
--- a/include/llvm/DebugInfo/GSYM/FileEntry.h
+++ b/include/llvm/DebugInfo/GSYM/FileEntry.h
@@ -1,9 +1,8 @@
 //===- FileEntry.h ----------------------------------------------*- C++ -*-===//
 //
-//                     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
 //
 //===----------------------------------------------------------------------===//
 
diff --git a/include/llvm/DebugInfo/GSYM/FileWriter.h b/include/llvm/DebugInfo/GSYM/FileWriter.h
new file mode 100644
index 000000000000..cd568765a4f2
--- /dev/null
+++ b/include/llvm/DebugInfo/GSYM/FileWriter.h
@@ -0,0 +1,124 @@
+//===- FileWriter.h ---------------------------------------------*- C++ -*-===//
+//
+// 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
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_DEBUGINFO_GSYM_FILEWRITER_H
+#define LLVM_DEBUGINFO_GSYM_FILEWRITER_H
+
+#include "llvm/ADT/ArrayRef.h"
+#include "llvm/Support/Endian.h"
+
+#include <stddef.h>
+#include <stdint.h>
+#include <sys/types.h>
+
+namespace llvm {
+class raw_pwrite_stream;
+
+namespace gsym {
+
+/// A simplified binary data writer class that doesn't require targets, target
+/// definitions, architectures, or require any other optional compile time
+/// libraries to be enabled via the build process. This class needs the ability
+/// to seek to different spots in the binary stream that is produces to fixup
+/// offsets and sizes.
+class FileWriter {
+  llvm::raw_pwrite_stream &OS;
+  llvm::support::endianness ByteOrder;
+public:
+  FileWriter(llvm::raw_pwrite_stream &S, llvm::support::endianness B)
+      : OS(S), ByteOrder(B) {}
+  ~FileWriter();
+  /// Write a single uint8_t value into the stream at the current file
+  /// position.
+  ///
+  /// \param   Value The value to write into the stream.
+  void writeU8(uint8_t Value);
+
+  /// Write a single uint16_t value into the stream at the current file
+  /// position. The value will be byte swapped if needed to match the byte
+  /// order specified during construction.
+  ///
+  /// \param   Value The value to write into the stream.
+  void writeU16(uint16_t Value);
+
+  /// Write a single uint32_t value into the stream at the current file
+  /// position. The value will be byte swapped if needed to match the byte
+  /// order specified during construction.
+  ///
+  /// \param   Value The value to write into the stream.
+  void writeU32(uint32_t Value);
+
+  /// Write a single uint64_t value into the stream at the current file
+  /// position. The value will be byte swapped if needed to match the byte
+  /// order specified during construction.
+  ///
+  /// \param   Value The value to write into the stream.
+  void writeU64(uint64_t Value);
+
+  /// Write the value into the stream encoded using signed LEB128 at the
+  /// current file position.
+  ///
+  /// \param   Value The value to write into the stream.
+  void writeSLEB(int64_t Value);
+
+  /// Write the value into the stream encoded using unsigned LEB128 at the
+  /// current file position.
+  ///
+  /// \param   Value The value to write into the stream.
+  void writeULEB(uint64_t Value);
+
+  /// Write an array of uint8_t values into the stream at the current file
+  /// position.
+  ///
+  /// \param   Data An array of values to write into the stream.
+  void writeData(llvm::ArrayRef<uint8_t> Data);
+
+  /// Write a NULL terminated C string into the stream at the current file
+  /// position. The entire contents of Str will be written into the steam at
+  /// the current file position and then an extra NULL termation byte will be
+  /// written. It is up to the user to ensure that Str doesn't contain any NULL
+  /// characters unless the additional NULL characters are desired.
+  ///
+  /// \param   Str The value to write into the stream.
+  void writeNullTerminated(llvm::StringRef Str);
+
+  /// Fixup a uint32_t value at the specified offset in the stream. This
+  /// function will save the current file position, seek to the specified
+  /// offset, overwrite the data using Value, and then restore the file
+  /// position to the previous file position.
+  ///
+  /// \param   Value The value to write into the stream.
+  /// \param   Offset The offset at which to write the Value within the stream.
+  void fixup32(uint32_t Value, uint64_t Offset);
+
+  /// Pad with zeroes at the current file position until the current file
+  /// position matches the specified alignment.
+  ///
+  /// \param  Align An integer speciying the desired alignment. This does not
+  ///         need to be a power of two.
+  void alignTo(size_t Align);
+
+  /// Return the current offset within the file.
+  ///
+  /// \return The unsigned offset from the start of the file of the current
+  ///         file position.
+  uint64_t tell();
+
+  llvm::raw_pwrite_stream &get_stream() {
+    return OS;
+  }
+
+private:
+  FileWriter(const FileWriter &rhs) = delete;
+  void operator=(const FileWriter &rhs) = delete;
+};
+
+} // namespace gsym
+} // namespace llvm
+
+#endif // #ifndef LLVM_DEBUGINFO_GSYM_FILEWRITER_H
diff --git a/include/llvm/DebugInfo/GSYM/FunctionInfo.h b/include/llvm/DebugInfo/GSYM/FunctionInfo.h
index eedb1e638fd1..63e18bb2ecd5 100644
--- a/include/llvm/DebugInfo/GSYM/FunctionInfo.h
+++ b/include/llvm/DebugInfo/GSYM/FunctionInfo.h
@@ -1,17 +1,17 @@
 //===- FunctionInfo.h -------------------------------------------*- C++ -*-===//
 //
-//                     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
 //
 //===----------------------------------------------------------------------===//
 
 #ifndef LLVM_DEBUGINFO_GSYM_FUNCTIONINFO_H
 #define LLVM_DEBUGINFO_GSYM_FUNCTIONINFO_H
 
+#include "llvm/ADT/Optional.h"
 #include "llvm/DebugInfo/GSYM/InlineInfo.h"
-#include "llvm/DebugInfo/GSYM/LineEntry.h"
+#include "llvm/DebugInfo/GSYM/LineTable.h"
 #include "llvm/DebugInfo/GSYM/Range.h"
 #include "llvm/DebugInfo/GSYM/StringTable.h"
 #include <tuple>
@@ -21,41 +21,125 @@ namespace llvm {
 class raw_ostream;
 namespace gsym {
 
-/// Function information in GSYM files encodes information for one
-/// contiguous address range. The name of the function is encoded as
-/// a string table offset and allows multiple functions with the same
-/// name to share the name string in the string table. Line tables are
-/// stored in a sorted vector of gsym::LineEntry objects and are split
-/// into line tables for each function. If a function has a discontiguous
-/// range, it will be split into two gsym::FunctionInfo objects. If the
-/// function has inline functions, the information will be encoded in
-/// the "Inline" member, see gsym::InlineInfo for more information.
+/// Function information in GSYM files encodes information for one contiguous
+/// address range. If a function has discontiguous address ranges, they will
+/// need to be encoded using multiple FunctionInfo objects.
+///
+/// ENCODING
+///
+/// The function information gets the function start address as an argument
+/// to the FunctionInfo::decode(...) function. This information is calculated
+/// from the GSYM header and an address offset from the GSYM address offsets
+/// table. The encoded FunctionInfo information must be alinged to a 4 byte
+/// boundary.
+///
+/// The encoded data for a FunctionInfo starts with fixed data that all
+/// function info objects have:
+///
+/// ENCODING  NAME        DESCRIPTION
+/// ========= =========== ====================================================
+/// uint32_t  Size        The size in bytes of this function.
+/// uint32_t  Name        The string table offset of the function name.
+///
+/// The optional data in a FunctionInfo object follows this fixed information
+/// and consists of a stream of tuples that consist of:
+///
+/// ENCODING  NAME        DESCRIPTION
+/// ========= =========== ====================================================
+/// uint32_t  InfoType    An "InfoType" enumeration that describes the type
+///                       of optional data that is encoded.
+/// uint32_t  InfoLength  The size in bytes of the encoded data that
+///                       immediately follows this length if this value is
+///                       greater than zero.
+/// uint8_t[] InfoData    Encoded bytes that represent the data for the
+///                       "InfoType". These bytes are only present if
+///                       "InfoLength" is greater than zero.
+///
+/// The "InfoType" is an enumeration:
+///
+///   enum InfoType {
+///     EndOfList = 0u,
+///     LineTableInfo = 1u,
+///     InlineInfo = 2u
+///   };
+///
+/// This stream of tuples is terminated by a "InfoType" whose value is
+/// InfoType::EndOfList and a zero for "InfoLength". This signifies the end of
+/// the optional information list. This format allows us to add new optional
+/// information data to a FunctionInfo object over time and allows older
+/// clients to still parse the format and skip over any data that they don't
+/// understand or want to parse.
+///
+/// So the function information encoding essientially looks like:
+///
+/// struct {
+///   uint32_t Size;
+///   uint32_t Name;
+///   struct {
+///     uint32_t InfoType;
+///     uint32_t InfoLength;
+///     uint8_t InfoData[InfoLength];
+///   }[N];
+/// }
+///
+/// Where "N" is the number of tuples.
 struct FunctionInfo {
   AddressRange Range;
   uint32_t Name; ///< String table offset in the string table.
-  std::vector<gsym::LineEntry> Lines;
-  InlineInfo Inline;
+  llvm::Optional<LineTable> OptLineTable;
+  llvm::Optional<InlineInfo> Inline;
 
   FunctionInfo(uint64_t Addr = 0, uint64_t Size = 0, uint32_t N = 0)
       : Range(Addr, Addr + Size), Name(N) {}
 
+  /// Query if a FunctionInfo has rich debug info.
+  ///
+  /// \returns A bool that indicates if this object has something else than
+  /// range and name. When converting information from a symbol table and from
+  /// debug info, we might end up with multiple FunctionInfo objects for the
+  /// same range and we need to be able to tell which one is the better object
+  /// to use.
   bool hasRichInfo() const {
-    /// Returns whether we have something else than range and name. When
-    /// converting information from a symbol table and from debug info, we
-    /// might end up with multiple FunctionInfo objects for the same range
-    /// and we need to be able to tell which one is the better object to use.
-    return !Lines.empty() || Inline.isValid();
+    return OptLineTable.hasValue() || Inline.hasValue();
   }
 
+  /// Query if a FunctionInfo object is valid.
+  ///
+  /// Address and size can be zero and there can be no line entries for a
+  /// symbol so the only indication this entry is valid is if the name is
+  /// not zero. This can happen when extracting information from symbol
+  /// tables that do not encode symbol sizes. In that case only the
+  /// address and name will be filled in.
+  ///
+  /// \returns A boolean indicating if this FunctionInfo is valid.
   bool isValid() const {
-    /// Address and size can be zero and there can be no line entries for a
-    /// symbol so the only indication this entry is valid is if the name is
-    /// not zero. This can happen when extracting information from symbol
-    /// tables that do not encode symbol sizes. In that case only the
-    /// address and name will be filled in.
     return Name != 0;
   }
 
+  /// Decode an object from a binary data stream.
+  ///
+  /// \param Data The binary stream to read the data from. This object must
+  /// have the data for the object starting at offset zero. The data
+  /// can contain more data than needed.
+  ///
+  /// \param BaseAddr The FunctionInfo's start address and will be used as the
+  /// base address when decoding any contained information like the line table
+  /// and the inline info.
+  ///
+  /// \returns An FunctionInfo or an error describing the issue that was
+  /// encountered during decoding.
+  static llvm::Expected<FunctionInfo> decode(DataExtractor &Data,
+                                             uint64_t BaseAddr);
+
+  /// Encode this object into FileWriter stream.
+  ///
+  /// \param O The binary stream to write the data to at the current file
+  /// position.
+  ///
+  /// \returns An error object that indicates failure or the offset of the
+  /// function info that was successfully written into the stream.
+  llvm::Expected<uint64_t> encode(FileWriter &O) const;
+
   uint64_t startAddress() const { return Range.Start; }
   uint64_t endAddress() const { return Range.End; }
   uint64_t size() const { return Range.size(); }
@@ -66,14 +150,14 @@ struct FunctionInfo {
   void clear() {
     Range = {0, 0};
     Name = 0;
-    Lines.clear();
-    Inline.clear();
+    OptLineTable = None;
+    Inline = None;
   }
 };
 
 inline bool operator==(const FunctionInfo &LHS, const FunctionInfo &RHS) {
   return LHS.Range == RHS.Range && LHS.Name == RHS.Name &&
-         LHS.Lines == RHS.Lines && LHS.Inline == RHS.Inline;
+         LHS.OptLineTable == RHS.OptLineTable && LHS.Inline == RHS.Inline;
 }
 inline bool operator!=(const FunctionInfo &LHS, const FunctionInfo &RHS) {
   return !(LHS == RHS);
@@ -89,14 +173,10 @@ inline bool operator<(const FunctionInfo &LHS, const FunctionInfo &RHS) {
     return LHS.Range < RHS.Range;
 
   // Then sort by inline
-  if (LHS.Inline.isValid() != RHS.Inline.isValid())
-    return RHS.Inline.isValid();
-
-  // If the number of lines is the same, then compare line table entries
-  if (LHS.Lines.size() == RHS.Lines.size())
-    return LHS.Lines < RHS.Lines;
-  // Then sort by number of line table entries (more is better)
-  return LHS.Lines.size() < RHS.Lines.size();
+  if (LHS.Inline.hasValue() != RHS.Inline.hasValue())
+    return RHS.Inline.hasValue();
+
+  return LHS.OptLineTable < RHS.OptLineTable;
 }
 
 raw_ostream &operator<<(raw_ostream &OS, const FunctionInfo &R);
diff --git a/include/llvm/DebugInfo/GSYM/GsymCreator.h b/include/llvm/DebugInfo/GSYM/GsymCreator.h
new file mode 100644
index 000000000000..12c8187132ba
--- /dev/null
+++ b/include/llvm/DebugInfo/GSYM/GsymCreator.h
@@ -0,0 +1,229 @@
+//===- GsymCreator.h --------------------------------------------*- C++ -*-===//
+//
+// 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
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_DEBUGINFO_GSYM_GSYMCREATOR_H
+#define LLVM_DEBUGINFO_GSYM_GSYMCREATOR_H
+
+#include <functional>
+#include <memory>
+#include <mutex>
+#include <string>
+#include <thread>
+
+#include "llvm/ADT/ArrayRef.h"
+#include "llvm/DebugInfo/GSYM/FileEntry.h"
+#include "llvm/DebugInfo/GSYM/FunctionInfo.h"
+#include "llvm/DebugInfo/GSYM/Range.h"
+#include "llvm/MC/StringTableBuilder.h"
+#include "llvm/Support/Endian.h"
+#include "llvm/Support/Error.h"
+#include "llvm/Support/Path.h"
+
+namespace llvm {
+
+namespace gsym {
+class FileWriter;
+
+/// GsymCreator is used to emit GSYM data to a stand alone file or section
+/// within a file.
+///
+/// The GsymCreator is designed to be used in 3 stages:
+/// - Create FunctionInfo objects and add them
+/// - Finalize the GsymCreator object
+/// - Save to file or section
+///
+/// The first stage involves creating FunctionInfo objects from another source
+/// of information like compiler debug info metadata, DWARF or Breakpad files.
+/// Any strings in the FunctionInfo or contained information, like InlineInfo
+/// or LineTable objects, should get the string table offsets by calling
+/// GsymCreator::insertString(...). Any file indexes that are needed should be
+/// obtained by calling GsymCreator::insertFile(...). All of the function calls
+/// in GsymCreator are thread safe. This allows multiple threads to create and
+/// add FunctionInfo objects while parsing debug information.
+///
+/// Once all of the FunctionInfo objects have been added, the
+/// GsymCreator::finalize(...) must be called prior to saving. This function
+/// will sort the FunctionInfo objects, finalize the string table, and do any
+/// other passes on the information needed to prepare the information to be
+/// saved.
+///
+/// Once the object has been finalized, it can be saved to a file or section.
+///
+/// ENCODING
+///
+/// GSYM files are designed to be memory mapped into a process as shared, read
+/// only data, and used as is.
+///
+/// The GSYM file format when in a stand alone file consists of:
+///   - Header
+///   - Address Table
+///   - Function Info Offsets
+///   - File Table
+///   - String Table
+///   - Function Info Data
+///
+/// HEADER
+///
+/// The header is fully described in "llvm/DebugInfo/GSYM/Header.h".
+///
+/// ADDRESS TABLE
+///
+/// The address table immediately follows the header in the file and consists
+/// of Header.NumAddresses address offsets. These offsets are sorted and can be
+/// binary searched for efficient lookups. Addresses in the address table are
+/// stored as offsets from a 64 bit base address found in Header.BaseAddress.
+/// This allows the address table to contain 8, 16, or 32 offsets. This allows
+/// the address table to not require full 64 bit addresses for each address.
+/// The resulting GSYM size is smaller and causes fewer pages to be touched
+/// during address lookups when the address table is smaller. The size of the
+/// address offsets in the address table is specified in the header in
+/// Header.AddrOffSize. The first offset in the address table is alinged to
+/// Header.AddrOffSize alignement to ensure efficient access when loaded into
+/// memory.
+///
+/// FUNCTION INFO OFFSETS TABLE
+///
+/// The function info offsets table immediately follows the address table and
+/// consists of Header.NumAddresses 32 bit file offsets: one for each address
+/// in the address table. This data is algined to a 4 byte boundary. The
+/// offsets in this table are the relative offsets from the start offset of the
+/// GSYM header and point to the function info data for each address in the
+/// address table. Keeping this data separate from the address table helps to
+/// reduce the number of pages that are touched when address lookups occur on a
+/// GSYM file.
+///
+/// FILE TABLE
+///
+/// The file table immediately follows the function info offsets table. The
+/// encoding of the FileTable is:
+///
+/// struct FileTable {
+///   uint32_t Count;
+///   FileEntry Files[];
+/// };
+///
+/// The file table starts with a 32 bit count of the number of files that are
+/// used in all of the function info, followed by that number of FileEntry
+/// structures. The file table is aligned to a 4 byte boundary, Each file in
+/// the file table is represented with a FileEntry structure.
+/// See "llvm/DebugInfo/GSYM/FileEntry.h" for details.
+///
+/// STRING TABLE
+///
+/// The string table follows the file table in stand alone GSYM files and
+/// contains all strings for everything contained in the GSYM file. Any string
+/// data should be added to the string table and any references to strings
+/// inside GSYM information must be stored as 32 bit string table offsets into
+/// this string table. The string table always starts with an empty string at
+/// offset zero and is followed by any strings needed by the GSYM information.
+/// The start of the string table is not aligned to any boundary.
+///
+/// FUNCTION INFO DATA
+///
+/// The function info data is the payload that contains information about the
+/// address that is being looked up. It contains all of the encoded
+/// FunctionInfo objects. Each encoded FunctionInfo's data is pointed to by an
+/// entry in the Function Info Offsets Table. For details on the exact encoding
+/// of FunctionInfo objects, see "llvm/DebugInfo/GSYM/FunctionInfo.h".
+class GsymCreator {
+  // Private member variables require Mutex protections
+  mutable std::recursive_mutex Mutex;
+  std::vector<FunctionInfo> Funcs;
+  StringTableBuilder StrTab;
+  DenseMap<llvm::gsym::FileEntry, uint32_t> FileEntryToIndex;
+  std::vector<llvm::gsym::FileEntry> Files;
+  std::vector<uint8_t> UUID;
+  bool Finalized = false;
+
+public:
+
+  GsymCreator();
+
+  /// Save a GSYM file to a stand alone file.
+  ///
+  /// \param Path The file path to save the GSYM file to.
+  /// \param ByteOrder The endianness to use when saving the file.
+  /// \returns An error object that indicates success or failure of the save.
+  llvm::Error save(StringRef Path, llvm::support::endianness ByteOrder) const;
+
+  /// Encode a GSYM into the file writer stream at the current position.
+  ///
+  /// \param O The stream to save the binary data to
+  /// \returns An error object that indicates success or failure of the save.
+  llvm::Error encode(FileWriter &O) const;
+
+  /// Insert a string into the GSYM string table.
+  ///
+  /// All strings used by GSYM files must be uniqued by adding them to this
+  /// string pool and using the returned offset for any string values.
+  ///
+  /// \param   S The string to insert into the string table.
+  /// \returns The unique 32 bit offset into the string table.
+  uint32_t insertString(StringRef S);
+
+  /// Insert a file into this GSYM creator.
+  ///
+  /// Inserts a file by adding a FileEntry into the "Files" member variable if
+  /// the file has not already been added. The file path is split into
+  /// directory and filename which are both added to the string table. This
+  /// allows paths to be stored efficiently by reusing the directories that are
+  /// common between multiple files.
+  ///
+  /// \param   Path The path to the file to insert.
+  /// \param   Style The path style for the "Path" parameter.
+  /// \returns The unique file index for the inserted file.
+  uint32_t insertFile(StringRef Path,
+                      sys::path::Style Style = sys::path::Style::native);
+
+  /// Add a function info to this GSYM creator.
+  ///
+  /// All information in the FunctionInfo object must use the
+  /// GsymCreator::insertString(...) function when creating string table
+  /// offsets for names and other strings.
+  ///
+  /// \param   FI The function info object to emplace into our functions list.
+  void addFunctionInfo(FunctionInfo &&FI);
+
+  /// Finalize the data in the GSYM creator prior to saving the data out.
+  ///
+  /// Finalize must be called after all FunctionInfo objects have been added
+  /// and before GsymCreator::save() is called.
+  ///
+  /// \param  OS Output stream to report duplicate function infos, overlapping
+  ///         function infos, and function infos that were merged or removed.
+  /// \returns An error object that indicates success or failure of the
+  ///          finalize.
+  llvm::Error finalize(llvm::raw_ostream &OS);
+
+  /// Set the UUID value.
+  ///
+  /// \param UUIDBytes The new UUID bytes.
+  void setUUID(llvm::ArrayRef<uint8_t> UUIDBytes) {
+    UUID.assign(UUIDBytes.begin(), UUIDBytes.end());
+  }
+
+  /// Thread safe iteration over all function infos.
+  ///
+  /// \param  Callback A callback function that will get called with each
+  ///         FunctionInfo. If the callback returns false, stop iterating.
+  void forEachFunctionInfo(
+      std::function<bool(FunctionInfo &)> const &Callback);
+
+  /// Thread safe const iteration over all function infos.
+  ///
+  /// \param  Callback A callback function that will get called with each
+  ///         FunctionInfo. If the callback returns false, stop iterating.
+  void forEachFunctionInfo(
+      std::function<bool(const FunctionInfo &)> const &Callback) const;
+
+};
+
+} // namespace gsym
+} // namespace llvm
+
+#endif // #ifndef LLVM_DEBUGINFO_GSYM_GSYMCREATOR_H
diff --git a/include/llvm/DebugInfo/GSYM/GsymReader.h b/include/llvm/DebugInfo/GSYM/GsymReader.h
new file mode 100644
index 000000000000..113bcee9c9a3
--- /dev/null
+++ b/include/llvm/DebugInfo/GSYM/GsymReader.h
@@ -0,0 +1,228 @@
+//===- GsymReader.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_GSYM_GSYMREADER_H
+#define LLVM_DEBUGINFO_GSYM_GSYMREADER_H
+
+
+#include "llvm/ADT/ArrayRef.h"
+#include "llvm/DebugInfo/GSYM/FileEntry.h"
+#include "llvm/DebugInfo/GSYM/FunctionInfo.h"
+#include "llvm/DebugInfo/GSYM/Header.h"
+#include "llvm/DebugInfo/GSYM/LineEntry.h"
+#include "llvm/DebugInfo/GSYM/StringTable.h"
+#include "llvm/Support/DataExtractor.h"
+#include "llvm/Support/Endian.h"
+#include "llvm/Support/ErrorOr.h"
+
+#include <inttypes.h>
+#include <memory>
+#include <stdint.h>
+#include <string>
+#include <vector>
+
+namespace llvm {
+class MemoryBuffer;
+class raw_ostream;
+
+namespace gsym {
+
+/// GsymReader is used to read GSYM data from a file or buffer.
+///
+/// This class is optimized for very quick lookups when the endianness matches
+/// the host system. The Header, address table, address info offsets, and file
+/// table is designed to be mmap'ed as read only into memory and used without
+/// any parsing needed. If the endianness doesn't match, we swap these objects
+/// and tables into GsymReader::SwappedData and then point our header and
+/// ArrayRefs to this swapped internal data.
+///
+/// GsymReader objects must use one of the static functions to create an
+/// instance: GsymReader::openFile(...) and GsymReader::copyBuffer(...).
+
+class GsymReader {
+  GsymReader(std::unique_ptr<MemoryBuffer> Buffer);
+  llvm::Error parse();
+
+  std::unique_ptr<MemoryBuffer> MemBuffer;
+  StringRef GsymBytes;
+  llvm::support::endianness Endian;
+  const Header *Hdr = nullptr;
+  ArrayRef<uint8_t> AddrOffsets;
+  ArrayRef<uint32_t> AddrInfoOffsets;
+  ArrayRef<FileEntry> Files;
+  StringTable StrTab;
+  /// When the GSYM file's endianness doesn't match the host system then
+  /// we must decode all data structures that need to be swapped into
+  /// local storage and set point the ArrayRef objects above to these swapped
+  /// copies.
+  struct SwappedData {
+    Header Hdr;
+    std::vector<uint8_t> AddrOffsets;
+    std::vector<uint32_t> AddrInfoOffsets;
+    std::vector<FileEntry> Files;
+  };
+  std::unique_ptr<SwappedData> Swap;
+
+public:
+  GsymReader(GsymReader &&RHS);
+  ~GsymReader();
+
+  /// Construct a GsymReader from a file on disk.
+  ///
+  /// \param Path The file path the GSYM file to read.
+  /// \returns An expected GsymReader that contains the object or an error
+  /// object that indicates reason for failing to read the GSYM.
+  static llvm::Expected<GsymReader> openFile(StringRef Path);
+
+  /// Construct a GsymReader from a buffer.
+  ///
+  /// \param Bytes A set of bytes that will be copied and owned by the
+  /// returned object on success.
+  /// \returns An expected GsymReader that contains the object or an error
+  /// object that indicates reason for failing to read the GSYM.
+  static llvm::Expected<GsymReader> copyBuffer(StringRef Bytes);
+
+  /// Access the GSYM header.
+  /// \returns A native endian version of the GSYM header.
+  const Header &getHeader() const;
+
+  /// Get the full function info for an address.
+  ///
+  /// \param Addr A virtual address from the orignal object file to lookup.
+  /// \returns An expected FunctionInfo that contains the function info object
+  /// or an error object that indicates reason for failing to lookup the
+  /// address,
+  llvm::Expected<FunctionInfo> getFunctionInfo(uint64_t Addr) const;
+
+  /// Get a string from the string table.
+  ///
+  /// \param Offset The string table offset for the string to retrieve.
+  /// \returns The string from the strin table.
+  StringRef getString(uint32_t Offset) const { return StrTab[Offset]; }
+
+protected:
+  /// Gets an address from the address table.
+  ///
+  /// Addresses are stored as offsets frrom the gsym::Header::BaseAddress.
+  ///
+  /// \param Index A index into the address table.
+  /// \returns A resolved virtual address for adddress in the address table
+  /// or llvm::None if Index is out of bounds.
+  Optional<uint64_t> getAddress(size_t Index) const;
+
+  /// Get the a file entry for the suppplied file index.
+  ///
+  /// Used to convert any file indexes in the FunctionInfo data back into
+  /// files. This function can be used for iteration, but is more commonly used
+  /// for random access when doing lookups.
+  ///
+  /// \param Index An index into the file table.
+  /// \returns An optional FileInfo that will be valid if the file index is
+  /// valid, or llvm::None if the file index is out of bounds,
+  Optional<FileEntry> getFile(uint32_t Index) const {
+    if (Index < Files.size())
+      return Files[Index];
+    return llvm::None;
+  }
+
+  /// Get an appropriate address info offsets array.
+  ///
+  /// The address table in the GSYM file is stored as array of 1, 2, 4 or 8
+  /// byte offsets from the The gsym::Header::BaseAddress. The table is stored
+  /// internally as a array of bytes that are in the correct endianness. When
+  /// we access this table we must get an array that matches those sizes. This
+  /// templatized helper function is used when accessing address offsets in the
+  /// AddrOffsets member variable.
+  ///
+  /// \returns An ArrayRef of an appropriate address offset size.
+  template <class T> ArrayRef<T>
+  getAddrOffsets() const {
+    return ArrayRef<T>(reinterpret_cast<const T *>(AddrOffsets.data()),
+                       AddrOffsets.size()/sizeof(T));
+  }
+
+  /// Get an appropriate address from the address table.
+  ///
+  /// The address table in the GSYM file is stored as array of 1, 2, 4 or 8
+  /// byte address offsets from the The gsym::Header::BaseAddress. The table is
+  /// stored internally as a array of bytes that are in the correct endianness.
+  /// In order to extract an address from the address table we must access the
+  /// address offset using the correct size and then add it to the BaseAddress
+  /// in the header.
+  ///
+  /// \param Index An index into the AddrOffsets array.
+  /// \returns An virtual address that matches the original object file for the
+  /// address as the specified index, or llvm::None if Index is out of bounds.
+  template <class T> Optional<uint64_t>
+  addressForIndex(size_t Index) const {
+    ArrayRef<T> AIO = getAddrOffsets<T>();
+    if (Index < AIO.size())
+      return AIO[Index] + Hdr->BaseAddress;
+    return llvm::None;
+  }
+  /// Lookup an address offset in the AddrOffsets table.
+  ///
+  /// Given an address offset, look it up using a binary search of the
+  /// AddrOffsets table.
+  ///
+  /// \param AddrOffset An address offset, that has already been computed by
+  /// subtracting the gsym::Header::BaseAddress.
+  /// \returns The matching address offset index. This index will be used to
+  /// extract the FunctionInfo data's offset from the AddrInfoOffsets array.
+  template <class T>
+  uint64_t getAddressOffsetIndex(const uint64_t AddrOffset) const {
+    ArrayRef<T> AIO = getAddrOffsets<T>();
+    const auto Begin = AIO.begin();
+    const auto End = AIO.end();
+    auto Iter = std::lower_bound(Begin, End, AddrOffset);
+    if (Iter == End || AddrOffset < *Iter)
+      --Iter;
+    return std::distance(Begin, Iter);
+  }
+
+  /// Create a GSYM from a memory buffer.
+  ///
+  /// Called by both openFile() and copyBuffer(), this function does all of the
+  /// work of parsing the GSYM file and returning an error.
+  ///
+  /// \param MemBuffer A memory buffer that will transfer ownership into the
+  /// GsymReader.
+  /// \returns An expected GsymReader that contains the object or an error
+  /// object that indicates reason for failing to read the GSYM.
+  static llvm::Expected<llvm::gsym::GsymReader>
+  create(std::unique_ptr<MemoryBuffer> &MemBuffer);
+
+
+  /// Given an address, find the address index.
+  ///
+  /// Binary search the address table and find the matching address index.
+  ///
+  /// \param Addr A virtual address that matches the original object file
+  /// to lookup.
+  /// \returns An index into the address table. This index can be used to
+  /// extract the FunctionInfo data's offset from the AddrInfoOffsets array.
+  /// Returns an error if the address isn't in the GSYM with details of why.
+  Expected<uint64_t> getAddressIndex(const uint64_t Addr) const;
+
+  /// Given an address index, get the offset for the FunctionInfo.
+  ///
+  /// Looking up an address is done by finding the corresponding address
+  /// index for the address. This index is then used to get the offset of the
+  /// FunctionInfo data that we will decode using this function.
+  ///
+  /// \param Index An index into the address table.
+  /// \returns An optional GSYM data offset for the offset of the FunctionInfo
+  /// that needs to be decoded.
+  Optional<uint64_t> getAddressInfoOffset(size_t Index) const;
+};
+
+} // namespace gsym
+} // namespace llvm
+
+#endif // #ifndef LLVM_DEBUGINFO_GSYM_GSYMREADER_H
diff --git a/include/llvm/DebugInfo/GSYM/Header.h b/include/llvm/DebugInfo/GSYM/Header.h
new file mode 100644
index 000000000000..6652c59c97a6
--- /dev/null
+++ b/include/llvm/DebugInfo/GSYM/Header.h
@@ -0,0 +1,129 @@
+//===- Header.h -------------------------------------------------*- C++ -*-===//
+//
+// 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
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_DEBUGINFO_GSYM_HEADER_H
+#define LLVM_DEBUGINFO_GSYM_HEADER_H
+
+#include "llvm/Support/Error.h"
+
+#include <cstddef>
+#include <cstdint>
+
+namespace llvm {
+class raw_ostream;
+class DataExtractor;
+
+namespace gsym {
+class FileWriter;
+
+constexpr uint32_t GSYM_MAGIC = 0x4753594d; // 'GSYM'
+constexpr uint32_t GSYM_CIGAM = 0x4d595347; // 'MYSG'
+constexpr uint32_t GSYM_VERSION = 1;
+constexpr size_t GSYM_MAX_UUID_SIZE = 20;
+
+/// The GSYM header.
+///
+/// The GSYM header is found at the start of a stand alone GSYM file, or as
+/// the first bytes in a section when GSYM is contained in a section of an
+/// executable file (ELF, mach-o, COFF).
+///
+/// The structure is encoded exactly as it appears in the structure definition
+/// with no gaps between members. Alignment should not change from system to
+/// system as the members were laid out so that they shouldn't align
+/// differently on different architectures.
+///
+/// When endianness of the system loading a GSYM file matches, the file can
+/// be mmap'ed in and a pointer to the header can be cast to the first bytes
+/// of the file (stand alone GSYM file) or section data (GSYM in a section).
+/// When endianness is swapped, the Header::decode() function should be used to
+/// decode the header.
+struct Header {
+  /// The magic bytes should be set to GSYM_MAGIC. This helps detect if a file
+  /// is a GSYM file by scanning the first 4 bytes of a file or section.
+  /// This value might appear byte swapped
+  uint32_t Magic;
+  /// The version can number determines how the header is decoded and how each
+  /// InfoType in FunctionInfo is encoded/decoded. As version numbers increase,
+  /// "Magic" and "Version" members should always appear at offset zero and 4
+  /// respectively to ensure clients figure out if they can parse the format.
+  uint16_t Version;
+  /// The size in bytes of each address offset in the address offsets table.
+  uint8_t AddrOffSize;
+  /// The size in bytes of the UUID encoded in the "UUID" member.
+  uint8_t UUIDSize;
+  /// The 64 bit base address that all address offsets in the address offsets
+  /// table are relative to. Storing a full 64 bit address allows our address
+  /// offsets table to be smaller on disk.
+  uint64_t BaseAddress;
+  /// The number of addresses stored in the address offsets table.
+  uint32_t NumAddresses;
+  /// The file relative offset of the start of the string table for strings
+  /// contained in the GSYM file. If the GSYM in contained in a stand alone
+  /// file this will be the file offset of the start of the string table. If
+  /// the GSYM is contained in a section within an executable file, this can
+  /// be the offset of the first string used in the GSYM file and can possibly
+  /// span one or more executable string tables. This allows the strings to
+  /// share string tables in an ELF or mach-o file.
+  uint32_t StrtabOffset;
+  /// The size in bytes of the string table. For a stand alone GSYM file, this
+  /// will be the exact size in bytes of the string table. When the GSYM data
+  /// is in a section within an executable file, this size can span one or more
+  /// sections that contains strings. This allows any strings that are already
+  /// stored in the executable file to be re-used, and any extra strings could
+  /// be added to another string table and the string table offset and size
+  /// can be set to span all needed string tables.
+  uint32_t StrtabSize;
+  /// The UUID of the original executable file. This is stored to allow
+  /// matching a GSYM file to an executable file when symbolication is
+  /// required. Only the first "UUIDSize" bytes of the UUID are valid. Any
+  /// bytes in the UUID value that appear after the first UUIDSize bytes should
+  /// be set to zero.
+  uint8_t UUID[GSYM_MAX_UUID_SIZE];
+
+  /// Check if a header is valid and return an error if anything is wrong.
+  ///
+  /// This function can be used prior to encoding a header to ensure it is
+  /// valid, or after decoding a header to ensure it is valid and supported.
+  ///
+  /// Check a correctly byte swapped header for errors:
+  ///   - check magic value
+  ///   - check that version number is supported
+  ///   - check that the address offset size is supported
+  ///   - check that the UUID size is valid
+  ///
+  /// \returns An error if anything is wrong in the header, or Error::success()
+  /// if there are no errors.
+  llvm::Error checkForError() const;
+
+  /// Decode an object from a binary data stream.
+  ///
+  /// \param Data The binary stream to read the data from. This object must
+  /// have the data for the object starting at offset zero. The data
+  /// can contain more data than needed.
+  ///
+  /// \returns A Header or an error describing the issue that was
+  /// encountered during decoding.
+  static llvm::Expected<Header> decode(DataExtractor &Data);
+
+  /// Encode this object into FileWriter stream.
+  ///
+  /// \param O The binary stream to write the data to at the current file
+  /// position.
+  ///
+  /// \returns An error object that indicates success or failure of the
+  /// encoding process.
+  llvm::Error encode(FileWriter &O) const;
+};
+
+bool operator==(const Header &LHS, const Header &RHS);
+raw_ostream &operator<<(raw_ostream &OS, const llvm::gsym::Header &H);
+
+} // namespace gsym
+} // namespace llvm
+
+#endif // #ifndef LLVM_DEBUGINFO_GSYM_HEADER_H
diff --git a/include/llvm/DebugInfo/GSYM/InlineInfo.h b/include/llvm/DebugInfo/GSYM/InlineInfo.h
index 222430622932..48fd9a7c1308 100644
--- a/include/llvm/DebugInfo/GSYM/InlineInfo.h
+++ b/include/llvm/DebugInfo/GSYM/InlineInfo.h
@@ -1,9 +1,8 @@
 //===- InlineInfo.h ---------------------------------------------*- C++ -*-===//
 //
-//                     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
 //
 //===----------------------------------------------------------------------===//
 
@@ -12,6 +11,7 @@
 
 #include "llvm/ADT/Optional.h"
 #include "llvm/DebugInfo/GSYM/Range.h"
+#include "llvm/Support/Error.h"
 #include <stdint.h>
 #include <vector>
 
@@ -31,6 +31,30 @@ namespace gsym {
 /// Any clients that encode information will need to ensure the ranges are
 /// all contined correctly or lookups could fail. Add ranges in these objects
 /// must be contained in the top level FunctionInfo address ranges as well.
+///
+/// ENCODING
+///
+/// When saved to disk, the inline info encodes all ranges to be relative to
+/// a parent address range. This will be the FunctionInfo's start address if
+/// the InlineInfo is directly contained in a FunctionInfo, or a the start
+/// address of the containing parent InlineInfo's first "Ranges" member. This
+/// allows address ranges to be efficiently encoded using ULEB128 encodings as
+/// we encode the offset and size of each range instead of full addresses. This
+/// also makes any encoded addresses easy to relocate as we just need to
+/// relocate the FunctionInfo's start address.
+///
+/// - The AddressRanges member "Ranges" is encoded using an approriate base
+///   address as described above.
+/// - UINT8 boolean value that specifies if the InlineInfo object has children.
+/// - UINT32 string table offset that points to the name of the inline
+///   function.
+/// - ULEB128 integer that specifies the file of the call site that called
+///   this function.
+/// - ULEB128 integer that specifies the source line of the call site that
+///   called this function.
+/// - if this object has children, enocode each child InlineInfo using the
+///   the first address range's start address as the base address.
+///
 struct InlineInfo {
 
   uint32_t Name; ///< String table offset in the string table.
@@ -62,6 +86,37 @@ struct InlineInfo {
   /// \returns optional vector of InlineInfo objects that describe the
   /// inline call stack for a given address, false otherwise.
   llvm::Optional<InlineArray> getInlineStack(uint64_t Addr) const;
+
+  /// Decode an InlineInfo object from a binary data stream.
+  ///
+  /// \param Data The binary stream to read the data from. This object must
+  /// have the data for the InlineInfo object starting at offset zero. The data
+  /// can contain more data than needed.
+  ///
+  /// \param BaseAddr The base address to use when decoding all address ranges.
+  /// This will be the FunctionInfo's start address if this object is directly
+  /// contained in a FunctionInfo object, or the start address of the first
+  /// address range in an InlineInfo object of this object is a child of
+  /// another InlineInfo object.
+  /// \returns An InlineInfo or an error describing the issue that was
+  /// encountered during decoding.
+  static llvm::Expected<InlineInfo> decode(DataExtractor &Data,
+                                           uint64_t BaseAddr);
+
+  /// Encode this InlineInfo object into FileWriter stream.
+  ///
+  /// \param O The binary stream to write the data to at the current file
+  /// position.
+  ///
+  /// \param BaseAddr The base address to use when encoding all address ranges.
+  /// This will be the FunctionInfo's start address if this object is directly
+  /// contained in a FunctionInfo object, or the start address of the first
+  /// address range in an InlineInfo object of this object is a child of
+  /// another InlineInfo object.
+  ///
+  /// \returns An error object that indicates success or failure or the
+  /// encoding process.
+  llvm::Error encode(FileWriter &O, uint64_t BaseAddr) const;
 };
 
 inline bool operator==(const InlineInfo &LHS, const InlineInfo &RHS) {
diff --git a/include/llvm/DebugInfo/GSYM/LineEntry.h b/include/llvm/DebugInfo/GSYM/LineEntry.h
index 6b9380940bd3..aac7c48e067e 100644
--- a/include/llvm/DebugInfo/GSYM/LineEntry.h
+++ b/include/llvm/DebugInfo/GSYM/LineEntry.h
@@ -1,9 +1,8 @@
 //===- LineEntry.h ----------------------------------------------*- C++ -*-===//
 //
-//                     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
 //
 //===----------------------------------------------------------------------===//
 
diff --git a/include/llvm/DebugInfo/GSYM/LineTable.h b/include/llvm/DebugInfo/GSYM/LineTable.h
new file mode 100644
index 000000000000..3cdbccb08ced
--- /dev/null
+++ b/include/llvm/DebugInfo/GSYM/LineTable.h
@@ -0,0 +1,198 @@
+//===- LineTable.h ----------------------------------------------*- C++ -*-===//
+//
+// 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
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_DEBUGINFO_GSYM_LINETABLE_H
+#define LLVM_DEBUGINFO_GSYM_LINETABLE_H
+
+#include "llvm/DebugInfo/GSYM/LineEntry.h"
+#include "llvm/Support/Error.h"
+#include <cstdint>
+#include <vector>
+
+namespace llvm {
+namespace gsym {
+
+struct FunctionInfo;
+class FileWriter;
+
+/// LineTable class contains deserialized versions of line tables for each
+/// function's address ranges.
+///
+/// When saved to disk, the line table is encoded using a modified version of
+/// the DWARF line tables that only tracks address to source file and line.
+///
+/// ENCODING
+///
+/// The line table starts with a small prolog that contains the following
+/// values:
+///
+/// ENCODING NAME        DESCRIPTION
+/// ======== =========== ====================================================
+/// SLEB     MinDelta    The min line delta for special opcodes that  advance
+///                      the address and line number.
+/// SLEB     MaxDelta    The max line delta for single byte opcodes that
+///                      advance the address and line number.
+/// ULEB     FirstLine   The value of the first source line number to
+///                      initialize the LineEntry with.
+///
+/// Once these prolog items are read, we initialize a LineEntry struct with
+/// the start address of the function from the FunctionInfo's address range,
+/// a default file index of 1, and the line number set to "FirstLine" from
+/// the prolog above:
+///
+///   LineEntry Row(BaseAddr, 1, FirstLine);
+///
+/// The line table state machine is now initialized and ready to be parsed.
+/// The stream that follows this encodes the line entries in a compact
+/// form. Some opcodes cause "Row" to be modified and some opcodes may also
+/// push "Row" onto the end of the "LineTable.Lines" vector. The end result
+/// is a vector of LineEntry structs that is sorted in ascending address
+/// order.
+///
+/// NORMAL OPCODES
+///
+/// The opcodes 0 through 3 are normal in opcodes. Their encoding and
+/// descriptions are listed below:
+///
+/// ENCODING ENUMERATION       VALUE DESCRIPTION
+/// ======== ================  ===== ========================================
+///          LTOC_EndSequence  0x00  Parsing is done.
+/// ULEB     LTOC_SetFile      0x01  Row.File = ULEB
+/// ULEB     LTOC_AdvancePC    0x02  Row.Addr += ULEB, push "Row".
+/// SLEB     LTOC_AdvanceLine  0x03  Row.Line += SLEB
+///          LTOC_FirstSpecial 0x04  First special opcode (see SPECIAL
+///                                  OPCODES below).
+///
+/// SPECIAL OPCODES
+///
+/// Opcodes LTOC_FirstSpecial through 255 are special opcodes that always
+/// increment both the Row.Addr and Row.Line and push "Row" onto the
+/// LineEntry.Lines array. They do this by using some of the bits to
+/// increment/decrement the source line number, and some of the bits to
+/// increment the address. Line numbers can go up or down when making line
+/// tables, where addresses always only increase since line tables are sorted
+/// by address.
+///
+/// In order to calculate the amount to increment the line and address for
+/// these special opcodes, we calculate the number of values reserved for the
+/// line increment/decrement using the "MinDelta" and "MaxDelta" from the
+/// prolog:
+///
+///     const int64_t LineRange = MaxDelta - MinDelta + 1;
+///
+/// Then we can adjust the opcode to not include any of the normal opcodes:
+///
+///     const uint8_t AdjustedOp = Opcode - LTOC_FirstSpecial;
+///
+/// And we can calculate the line offset, and address offset:
+///
+///     const int64_t LineDelta = MinDelta + (AdjustedOp % LineRange);
+///     const uint64_t AddrDelta = (AdjustedOp / LineRange);
+///
+/// And use these to modify our "Row":
+///
+///     Row.Line += LineDelta;
+///     Row.Addr += AddrDelta;
+///
+/// And push a row onto the line table:
+///
+///     Lines.push_back(Row);
+///
+/// This is verify similar to the way that DWARF encodes its line tables. The
+/// only difference is the DWARF line tables have more normal opcodes and the
+/// "Row" contains more members, like source column number, bools for end of
+/// prologue, beginnging of epilogue, is statement and many others. There are
+/// also more complex rules that happen for the extra normal opcodes. By
+/// leaving these extra opcodes out, we leave more bits for the special
+/// opcodes that allows us to encode line tables in fewer bytes than standard
+/// DWARF encodings.
+///
+/// Opcodes that will push "Row" onto the LineEntry.Lines include the
+/// LTOC_AdvancePC opcode and all special opcodes. All other opcodes
+/// only modify the current "Row", or cause the line table to end.
+class LineTable {
+  typedef std::vector<gsym::LineEntry> Collection;
+  Collection Lines; ///< All line entries in the line table.
+public:
+  static LineEntry lookup(DataExtractor &Data, uint64_t BaseAddr,
+                          uint64_t Addr);
+
+  /// Decode an LineTable object from a binary data stream.
+  ///
+  /// \param Data The binary stream to read the data from. This object must
+  /// have the data for the LineTable object starting at offset zero. The data
+  /// can contain more data than needed.
+  ///
+  /// \param BaseAddr The base address to use when decoding the line table.
+  /// This will be the FunctionInfo's start address and will be used to
+  /// initialize the line table row prior to parsing any opcodes.
+  ///
+  /// \returns An LineTable or an error describing the issue that was
+  /// encountered during decoding.
+  static llvm::Expected<LineTable> decode(DataExtractor &Data,
+                                          uint64_t BaseAddr);
+  /// Encode this LineTable object into FileWriter stream.
+  ///
+  /// \param O The binary stream to write the data to at the current file
+  /// position.
+  ///
+  /// \param BaseAddr The base address to use when decoding the line table.
+  /// This will be the FunctionInfo's start address.
+  ///
+  /// \returns An error object that indicates success or failure or the
+  /// encoding process.
+  llvm::Error encode(FileWriter &O, uint64_t BaseAddr) const;
+  bool empty() const { return Lines.empty(); }
+  void clear() { Lines.clear(); }
+  void push(const LineEntry &LE) {
+    Lines.push_back(LE);
+  }
+  size_t isValid() const {
+    return !Lines.empty();
+  }
+  size_t size() const {
+    return Lines.size();
+  }
+  LineEntry &get(size_t i) {
+    assert(i < Lines.size());
+    return Lines[i];
+  }
+  const LineEntry &get(size_t i) const {
+    assert(i < Lines.size());
+    return Lines[i];
+  }
+  LineEntry &operator[](size_t i) {
+    return get(i);
+  }
+  const LineEntry &operator[](size_t i) const {
+    return get(i);
+  }
+  bool operator==(const LineTable &RHS) const {
+    return Lines == RHS.Lines;
+  }
+  bool operator!=(const LineTable &RHS) const {
+    return Lines != RHS.Lines;
+  }
+  bool operator<(const LineTable &RHS) const {
+    const auto LHSSize = Lines.size();
+    const auto RHSSize = RHS.Lines.size();
+    if (LHSSize == RHSSize)
+      return Lines < RHS.Lines;
+    return LHSSize < RHSSize;
+  }
+  Collection::const_iterator begin() const { return Lines.begin(); }
+  Collection::const_iterator end() const { return Lines.end(); }
+
+};
+
+raw_ostream &operator<<(raw_ostream &OS, const gsym::LineTable &LT);
+
+} // namespace gsym
+} // namespace llvm
+
+#endif // #ifndef LLVM_DEBUGINFO_GSYM_LINETABLE_H
diff --git a/include/llvm/DebugInfo/GSYM/Range.h b/include/llvm/DebugInfo/GSYM/Range.h
index 772ff244c5b7..37cfec713f26 100644
--- a/include/llvm/DebugInfo/GSYM/Range.h
+++ b/include/llvm/DebugInfo/GSYM/Range.h
@@ -1,9 +1,8 @@
-//===- AddressRange.h -------------------------------------------*- C++ -*-===//
+//===- Range.h --------------------------------------------------*- C++ -*-===//
 //
-//                     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
 //
 //===----------------------------------------------------------------------===//
 
@@ -21,10 +20,13 @@
 #define HEX64(v) llvm::format_hex(v, 18)
 
 namespace llvm {
+class DataExtractor;
 class raw_ostream;
 
 namespace gsym {
 
+class FileWriter;
+
 /// A class that represents an address range. The range is specified using
 /// a start and an end address.
 struct AddressRange {
@@ -47,6 +49,18 @@ struct AddressRange {
   bool operator<(const AddressRange &R) const {
     return std::make_pair(Start, End) < std::make_pair(R.Start, R.End);
   }
+  /// AddressRange objects are encoded and decoded to be relative to a base
+  /// address. This will be the FunctionInfo's start address if the AddressRange
+  /// is directly contained in a FunctionInfo, or a base address of the
+  /// containing parent AddressRange or AddressRanges. This allows address
+  /// ranges to be efficiently encoded using ULEB128 encodings as we encode the
+  /// offset and size of each range instead of full addresses. This also makes
+  /// encoded addresses easy to relocate as we just need to relocate one base
+  /// address.
+  /// @{
+  void decode(DataExtractor &Data, uint64_t BaseAddr, uint64_t &Offset);
+  void encode(FileWriter &O, uint64_t BaseAddr) const;
+  /// @}
 };
 
 raw_ostream &operator<<(raw_ostream &OS, const AddressRange &R);
@@ -66,6 +80,7 @@ public:
   void clear() { Ranges.clear(); }
   bool empty() const { return Ranges.empty(); }
   bool contains(uint64_t Addr) const;
+  bool contains(AddressRange Range) const;
   void insert(AddressRange Range);
   size_t size() const { return Ranges.size(); }
   bool operator==(const AddressRanges &RHS) const {
@@ -77,6 +92,14 @@ public:
   }
   Collection::const_iterator begin() const { return Ranges.begin(); }
   Collection::const_iterator end() const { return Ranges.end(); }
+
+  /// Address ranges are decoded and encoded to be relative to a base address.
+  /// See the AddressRange comment for the encode and decode methods for full
+  /// details.
+  /// @{
+  void decode(DataExtractor &Data, uint64_t BaseAddr, uint64_t &Offset);
+  void encode(FileWriter &O, uint64_t BaseAddr) const;
+  /// @}
 };
 
 raw_ostream &operator<<(raw_ostream &OS, const AddressRanges &AR);
diff --git a/include/llvm/DebugInfo/GSYM/StringTable.h b/include/llvm/DebugInfo/GSYM/StringTable.h
index 0001b8b82743..a96ae5899da3 100644
--- a/include/llvm/DebugInfo/GSYM/StringTable.h
+++ b/include/llvm/DebugInfo/GSYM/StringTable.h
@@ -1,9 +1,8 @@
 //===- StringTable.h --------------------------------------------*- C++ -*-===//
 //
-//                     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
 //
 //===----------------------------------------------------------------------===//