Update prebuilt Clang to r416183b from Android.

https://android.googlesource.com/platform/prebuilts/clang/host/
linux-x86/+/06a71ddac05c22edb2d10b590e1769b3f8619bef

clang 12.0.5 (based on r416183b) from build 7284624.

Change-Id: I277a316abcf47307562d8b748b84870f31a72866
Signed-off-by: Olivier Deprez <olivier.deprez@arm.com>
diff --git a/linux-x64/clang/include/llvm/DebugInfo/GSYM/LineTable.h b/linux-x64/clang/include/llvm/DebugInfo/GSYM/LineTable.h
new file mode 100644
index 0000000..fba9b2c
--- /dev/null
+++ b/linux-x64/clang/include/llvm/DebugInfo/GSYM/LineTable.h
@@ -0,0 +1,233 @@
+//===- 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:
+  /// Lookup a single address within a line table's data.
+  ///
+  /// Clients have the option to decode an entire line table using
+  /// LineTable::decode() or just find a single matching entry using this
+  /// function. The benefit of using this function is that parsed LineEntry
+  /// objects that do not match will not be stored in an array. This will avoid
+  /// memory allocation costs and parsing can stop once a match has been found.
+  ///
+  /// \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 LineEntry object if a match is found, error otherwise.
+  static Expected<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(); }
+  /// Return the first line entry if the line table isn't empty.
+  ///
+  /// \returns An optional line entry with the first line entry if the line
+  /// table isn't empty, or llvm::None if the line table is emtpy.
+  Optional<LineEntry> first() const {
+    if (Lines.empty())
+      return llvm::None;
+    return Lines.front();
+  }
+  /// Return the last line entry if the line table isn't empty.
+  ///
+  /// \returns An optional line entry with the last line entry if the line
+  /// table isn't empty, or llvm::None if the line table is emtpy.
+  Optional<LineEntry> last() const {
+    if (Lines.empty())
+      return llvm::None;
+    return Lines.back();
+  }
+  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