Merge clang, llvm, lld, lldb, compiler-rt and libc++ 5.0.0 release.

MFC r309126 (by emaste):

  Correct lld llvm-tblgen dependency file name

MFC r309169:

  Get rid of separate Subversion mergeinfo properties for llvm-dwarfdump
  and llvm-lto.  The mergeinfo confuses Subversion enormously, and these
  directories will just use the mergeinfo for llvm itself.

MFC r312765:

  Pull in r276136 from upstream llvm trunk (by Wei Mi):

    Use ValueOffsetPair to enhance value reuse during SCEV expansion.

    In D12090, the ExprValueMap was added to reuse existing value during
    SCEV expansion. However, const folding and sext/zext distribution can
    make the reuse still difficult.

    A simplified case is: suppose we know S1 expands to V1 in
    ExprValueMap, and
      S1 = S2 + C_a
      S3 = S2 + C_b
    where C_a and C_b are different SCEVConstants. Then we'd like to
    expand S3 as V1 - C_a + C_b instead of expanding S2 literally. It is
    helpful when S2 is a complex SCEV expr and S2 has no entry in
    ExprValueMap, which is usually caused by the fact that S3 is
    generated from S1 after const folding.

    In order to do that, we represent ExprValueMap as a mapping from SCEV
    to ValueOffsetPair. We will save both S1->{V1, 0} and S2->{V1, C_a}
    into the ExprValueMap when we create SCEV for V1. When S3 is
    expanded, it will first expand S2 to V1 - C_a because of S2->{V1,
    C_a} in the map, then expand S3 to V1 - C_a + C_b.

    Differential Revision: https://reviews.llvm.org/D21313

  This should fix assertion failures when building OpenCV >= 3.1.

  PR:		215649

MFC r312831:

  Revert r312765 for now, since it causes assertions when building
  lang/spidermonkey24.

  Reported by:	antoine
  PR:		215649

MFC r316511 (by jhb):

  Add an implementation of __ffssi2() derived from __ffsdi2().

  Newer versions of GCC include an __ffssi2() symbol in libgcc and the
  compiler can emit calls to it in generated code.  This is true for at
  least GCC 6.2 when compiling world for mips and mips64.

  Reviewed by:	jmallett, dim
  Sponsored by:	DARPA / AFRL
  Differential Revision:	https://reviews.freebsd.org/D10086

MFC r318601 (by adrian):

  [libcompiler-rt] add bswapdi2/bswapsi2

  This is required for mips gcc 6.3 userland to build/run.

  Reviewed by:	emaste, dim
  Approved by:	emaste
  Differential Revision:	https://reviews.freebsd.org/D10838

MFC r318884 (by emaste):

  lldb: map TRAP_CAP to a trace trap

  In the absense of a more specific handler for TRAP_CAP (generated by
  ENOTCAPABLE or ECAPMODE while in capability mode) treat it as a trace
  trap.

  Example usage (testing the bug in PR219173):

  % proccontrol -m trapcap lldb usr.bin/hexdump/obj/hexdump -- -Cv -s 1 /bin/ls
  ...
  (lldb) run
  Process 12980 launching
  Process 12980 launched: '.../usr.bin/hexdump/obj/hexdump' (x86_64)
  Process 12980 stopped
  * thread #1, stop reason = trace
      frame #0: 0x0000004b80c65f1a libc.so.7`__sys_lseek + 10
  ...

  In the future we should have LLDB control the trapcap procctl itself
  (as it does with ASLR), as well as report a specific stop reason.
  This change eliminates an assertion failure from LLDB for now.

MFC r319796:

  Remove a few unneeded files from libllvm, libclang and liblldb.

MFC r319885 (by emaste):

  lld: ELF: Fix ICF crash on absolute symbol relocations.

  If two sections contained relocations to absolute symbols with the same
  value we would crash when trying to access their sections. Add a check that
  both symbols point to sections before accessing their sections, and treat
  absolute symbols as equal if their values are equal.

  Obtained from:	LLD commit r292578

MFC r319918:

  Revert r319796 for now, it can cause undefined references when linking
  in some circumstances.

  Reported by:	Shawn Webb <shawn.webb@hardenedbsd.org>

MFC r319957 (by emaste):

  lld: Add armelf emulation mode

  Obtained from:	LLD r305375

MFC r321369:

  Upgrade our copies of clang, llvm, lld, lldb, compiler-rt and libc++ to
  5.0.0 (trunk r308421).  Upstream has branched for the 5.0.0 release,
  which should be in about a month.  Please report bugs and regressions,
  so we can get them into the release.

  Please note that from 3.5.0 onwards, clang, llvm and lldb require C++11
  support to build; see UPDATING for more information.

MFC r321420:

  Add a few more object files to liblldb, which should solve errors when
  linking the lldb executable in some cases.  In particular, when the
  -ffunction-sections -fdata-sections options are turned off, or
  ineffective.

  Reported by:	Shawn Webb, Mark Millard

MFC r321433:

  Cleanup stale Options.inc files from the previous libllvm build for
  clang 4.0.0.  Otherwise, these can get included before the two newly
  generated ones (which are different) for clang 5.0.0.

  Reported by:	Mark Millard

MFC r321439 (by bdrewery):

  Move llvm Options.inc hack from r321433 for NO_CLEAN to lib/clang/libllvm.

  The files are only ever generated to .OBJDIR, not to WORLDTMP (as a
  sysroot) and are only ever included from a compilation.  So using
  a beforebuild target here removes the file before the compilation
  tries to include it.

MFC r321664:

  Pull in r308891 from upstream llvm trunk (by Benjamin Kramer):

    [CodeGenPrepare] Cut off FindAllMemoryUses if there are too many uses.

    This avoids excessive compile time. The case I'm looking at is
    Function.cpp from an old version of LLVM that still had the giant
    memcmp string matcher in it. Before r308322 this compiled in about 2
    minutes, after it, clang takes infinite* time to compile it. With
    this patch we're at 5 min, which is still bad but this is a
    pathological case.

    The cut off at 20 uses was chosen by looking at other cut-offs in LLVM
    for user scanning. It's probably too high, but does the job and is
    very unlikely to regress anything.

    Fixes PR33900.

    * I'm impatient and aborted after 15 minutes, on the bug report it was
      killed after 2h.

  Pull in r308986 from upstream llvm trunk (by Simon Pilgrim):

    [X86][CGP] Reduce memcmp() expansion to 2 load pairs (PR33914)

    D35067/rL308322 attempted to support up to 4 load pairs for memcmp
    inlining which resulted in regressions for some optimized libc memcmp
    implementations (PR33914).

    Until we can match these more optimal cases, this patch reduces the
    memcmp expansion to a maximum of 2 load pairs (which matches what we
    do for -Os).

    This patch should be considered for the 5.0.0 release branch as well

    Differential Revision: https://reviews.llvm.org/D35830

  These fix a hang (or extremely long compile time) when building older
  LLVM ports.

  Reported by:    antoine
  PR:             219139

MFC r321719:

  Pull in r309503 from upstream clang trunk (by Richard Smith):

    PR33902: Invalidate line number cache when adding more text to
    existing buffer.

    This led to crashes as the line number cache would report a bogus
    line number for a line of code, and we'd try to find a nonexistent
    column within the line when printing diagnostics.

  This fixes an assertion when building the graphics/champlain port.

  Reported by:	antoine, kwm
  PR:		219139

MFC r321723:

  Upgrade our copies of clang, llvm, lld and lldb to r309439 from the
  upstream release_50 branch.  This is just after upstream's 5.0.0-rc1.

MFC r322320:

  Upgrade our copies of clang, llvm and libc++ to r310316 from the
  upstream release_50 branch.

MFC r322326 (by emaste):

  lldb: Make i386-*-freebsd expression work on JIT path

  * Enable i386 ABI creation for freebsd
  * Added an extra argument in ABISysV_i386::PrepareTrivialCall for mmap
    syscall
  * Unlike linux, the last argument of mmap is actually 64-bit(off_t).
    This requires us to push an additional word for the higher order bits.
  * Prior to this change, ktrace dump will show mmap failures due to
    invalid argument coming from the 6th mmap argument.

  Submitted by:	Karnajit Wangkhem
  Differential Revision:	https://reviews.llvm.org/D34776

MFC r322360 (by emaste):

  lldb: Report inferior signals as signals, not exceptions, on FreeBSD

  This is the FreeBSD equivalent of LLVM r238549.

  This serves 2 purposes:

  * LLDB should handle inferior process signals SIGSEGV/SIGILL/SIGBUS/
    SIGFPE the way it is suppose to be handled. Prior to this fix these
    signals will neither create a coredump, nor exit from the debugger
    or work for signal handling scenario.
  * eInvalidCrashReason need not report "unknown crash reason" if we have
    a valid si_signo

  llvm.org/pr23699

  Patch by Karnajit Wangkhem

  Differential Revision:  https://reviews.llvm.org/D35223

  Submitted by:	Karnajit Wangkhem
  Obtained from:	LLVM r310591

MFC r322474 (by emaste):

  lld: Add `-z muldefs` option.

  Obtained from:	LLVM r310757

MFC r322740:

  Upgrade our copies of clang, llvm, lld and libc++ to r311219 from the
  upstream release_50 branch.

MFC r322855:

  Upgrade our copies of clang, llvm, lldb and compiler-rt to r311606 from
  the upstream release_50 branch.

  As of this version, lib/msun's trig test should also work correctly
  again (see bug 220989 for more information).

  PR:		220989

MFC r323112:

  Upgrade our copies of clang, llvm, lldb and compiler-rt to r312293 from
  the upstream release_50 branch.  This corresponds to 5.0.0 rc4.

  As of this version, the cad/stepcode port should now compile in a more
  reasonable time on i386 (see bug 221836 for more information).

  PR:		221836

MFC r323245:

  Upgrade our copies of clang, llvm, lld, lldb, compiler-rt and libc++ to
  5.0.0 release (upstream r312559).

  Release notes for llvm, clang and lld will be available here soon:
  <http://releases.llvm.org/5.0.0/docs/ReleaseNotes.html>
  <http://releases.llvm.org/5.0.0/tools/clang/docs/ReleaseNotes.html>
  <http://releases.llvm.org/5.0.0/tools/lld/docs/ReleaseNotes.html>

  Relnotes:	yes

(cherry picked from commit 12cd91cf4c6b96a24427c0de5374916f2808d263)

1 files changed, 383 insertions, 20 deletions

diff --git a/contrib/llvm/lib/XRay/Trace.cpp b/contrib/llvm/lib/XRay/Trace.cpp
index 51000c7..6677063 100644
--- a/contrib/llvm/lib/XRay/Trace.cpp
+++ b/contrib/llvm/lib/XRay/Trace.cpp
@@ -24,8 +24,8 @@ using llvm::yaml::Input;
 using XRayRecordStorage =
     std::aligned_storage<sizeof(XRayRecord), alignof(XRayRecord)>::type;
 
-Error NaiveLogLoader(StringRef Data, XRayFileHeader &FileHeader,
-                     std::vector<XRayRecord> &Records) {
+// Populates the FileHeader reference by reading the first 32 bytes of the file.
+Error readBinaryFormatHeader(StringRef Data, XRayFileHeader &FileHeader) {
   // FIXME: Maybe deduce whether the data is little or big-endian using some
   // magic bytes in the beginning of the file?
 
@@ -37,16 +37,6 @@ Error NaiveLogLoader(StringRef Data, XRayFileHeader &FileHeader,
   //   (4)   uint32 : bitfield
   //   (8)   uint64 : cycle frequency
   //   (16)  -      : padding
-  //
-  if (Data.size() < 32)
-    return make_error<StringError>(
-        "Not enough bytes for an XRay log.",
-        std::make_error_code(std::errc::invalid_argument));
-
-  if (Data.size() - 32 == 0 || Data.size() % 32 != 0)
-    return make_error<StringError>(
-        "Invalid-sized XRay data.",
-        std::make_error_code(std::errc::invalid_argument));
 
   DataExtractor HeaderExtractor(Data, true, 8);
   uint32_t OffsetPtr = 0;
@@ -56,11 +46,29 @@ Error NaiveLogLoader(StringRef Data, XRayFileHeader &FileHeader,
   FileHeader.ConstantTSC = Bitfield & 1uL;
   FileHeader.NonstopTSC = Bitfield & 1uL << 1;
   FileHeader.CycleFrequency = HeaderExtractor.getU64(&OffsetPtr);
-
+  std::memcpy(&FileHeader.FreeFormData, Data.bytes_begin() + OffsetPtr, 16);
   if (FileHeader.Version != 1)
     return make_error<StringError>(
         Twine("Unsupported XRay file version: ") + Twine(FileHeader.Version),
         std::make_error_code(std::errc::invalid_argument));
+  return Error::success();
+}
+
+Error loadNaiveFormatLog(StringRef Data, XRayFileHeader &FileHeader,
+                         std::vector<XRayRecord> &Records) {
+  // Check that there is at least a header
+  if (Data.size() < 32)
+    return make_error<StringError>(
+        "Not enough bytes for an XRay log.",
+        std::make_error_code(std::errc::invalid_argument));
+
+  if (Data.size() - 32 == 0 || Data.size() % 32 != 0)
+    return make_error<StringError>(
+        "Invalid-sized XRay data.",
+        std::make_error_code(std::errc::invalid_argument));
+
+  if (auto E = readBinaryFormatHeader(Data, FileHeader))
+    return E;
 
   // Each record after the header will be 32 bytes, in the following format:
   //
@@ -98,9 +106,357 @@ Error NaiveLogLoader(StringRef Data, XRayFileHeader &FileHeader,
   return Error::success();
 }
 
-Error YAMLLogLoader(StringRef Data, XRayFileHeader &FileHeader,
-                    std::vector<XRayRecord> &Records) {
+/// When reading from a Flight Data Recorder mode log, metadata records are
+/// sparse compared to packed function records, so we must maintain state as we
+/// read through the sequence of entries. This allows the reader to denormalize
+/// the CPUId and Thread Id onto each Function Record and transform delta
+/// encoded TSC values into absolute encodings on each record.
+struct FDRState {
+  uint16_t CPUId;
+  uint16_t ThreadId;
+  uint64_t BaseTSC;
+
+  /// Encode some of the state transitions for the FDR log reader as explicit
+  /// checks. These are expectations for the next Record in the stream.
+  enum class Token {
+    NEW_BUFFER_RECORD_OR_EOF,
+    WALLCLOCK_RECORD,
+    NEW_CPU_ID_RECORD,
+    FUNCTION_SEQUENCE,
+    SCAN_TO_END_OF_THREAD_BUF,
+    CUSTOM_EVENT_DATA,
+  };
+  Token Expects;
+
+  // Each threads buffer may have trailing garbage to scan over, so we track our
+  // progress.
+  uint64_t CurrentBufferSize;
+  uint64_t CurrentBufferConsumed;
+};
+
+Twine fdrStateToTwine(const FDRState::Token &state) {
+  switch (state) {
+  case FDRState::Token::NEW_BUFFER_RECORD_OR_EOF:
+    return "NEW_BUFFER_RECORD_OR_EOF";
+  case FDRState::Token::WALLCLOCK_RECORD:
+    return "WALLCLOCK_RECORD";
+  case FDRState::Token::NEW_CPU_ID_RECORD:
+    return "NEW_CPU_ID_RECORD";
+  case FDRState::Token::FUNCTION_SEQUENCE:
+    return "FUNCTION_SEQUENCE";
+  case FDRState::Token::SCAN_TO_END_OF_THREAD_BUF:
+    return "SCAN_TO_END_OF_THREAD_BUF";
+  case FDRState::Token::CUSTOM_EVENT_DATA:
+    return "CUSTOM_EVENT_DATA";
+  }
+  return "UNKNOWN";
+}
+
+/// State transition when a NewBufferRecord is encountered.
+Error processFDRNewBufferRecord(FDRState &State, uint8_t RecordFirstByte,
+                                DataExtractor &RecordExtractor) {
+
+  if (State.Expects != FDRState::Token::NEW_BUFFER_RECORD_OR_EOF)
+    return make_error<StringError>(
+        "Malformed log. Read New Buffer record kind out of sequence",
+        std::make_error_code(std::errc::executable_format_error));
+  uint32_t OffsetPtr = 1; // 1 byte into record.
+  State.ThreadId = RecordExtractor.getU16(&OffsetPtr);
+  State.Expects = FDRState::Token::WALLCLOCK_RECORD;
+  return Error::success();
+}
+
+/// State transition when an EndOfBufferRecord is encountered.
+Error processFDREndOfBufferRecord(FDRState &State, uint8_t RecordFirstByte,
+                                  DataExtractor &RecordExtractor) {
+  if (State.Expects == FDRState::Token::NEW_BUFFER_RECORD_OR_EOF)
+    return make_error<StringError>(
+        "Malformed log. Received EOB message without current buffer.",
+        std::make_error_code(std::errc::executable_format_error));
+  State.Expects = FDRState::Token::SCAN_TO_END_OF_THREAD_BUF;
+  return Error::success();
+}
+
+/// State transition when a NewCPUIdRecord is encountered.
+Error processFDRNewCPUIdRecord(FDRState &State, uint8_t RecordFirstByte,
+                               DataExtractor &RecordExtractor) {
+  if (State.Expects != FDRState::Token::FUNCTION_SEQUENCE &&
+      State.Expects != FDRState::Token::NEW_CPU_ID_RECORD)
+    return make_error<StringError>(
+        "Malformed log. Read NewCPUId record kind out of sequence",
+        std::make_error_code(std::errc::executable_format_error));
+  uint32_t OffsetPtr = 1; // Read starting after the first byte.
+  State.CPUId = RecordExtractor.getU16(&OffsetPtr);
+  State.BaseTSC = RecordExtractor.getU64(&OffsetPtr);
+  State.Expects = FDRState::Token::FUNCTION_SEQUENCE;
+  return Error::success();
+}
+
+/// State transition when a TSCWrapRecord (overflow detection) is encountered.
+Error processFDRTSCWrapRecord(FDRState &State, uint8_t RecordFirstByte,
+                              DataExtractor &RecordExtractor) {
+  if (State.Expects != FDRState::Token::FUNCTION_SEQUENCE)
+    return make_error<StringError>(
+        "Malformed log. Read TSCWrap record kind out of sequence",
+        std::make_error_code(std::errc::executable_format_error));
+  uint32_t OffsetPtr = 1; // Read starting after the first byte.
+  State.BaseTSC = RecordExtractor.getU64(&OffsetPtr);
+  return Error::success();
+}
+
+/// State transition when a WallTimeMarkerRecord is encountered.
+Error processFDRWallTimeRecord(FDRState &State, uint8_t RecordFirstByte,
+                               DataExtractor &RecordExtractor) {
+  if (State.Expects != FDRState::Token::WALLCLOCK_RECORD)
+    return make_error<StringError>(
+        "Malformed log. Read Wallclock record kind out of sequence",
+        std::make_error_code(std::errc::executable_format_error));
+  // We don't encode the wall time into any of the records.
+  // XRayRecords are concerned with the TSC instead.
+  State.Expects = FDRState::Token::NEW_CPU_ID_RECORD;
+  return Error::success();
+}
+
+/// State transition when a CustomEventMarker is encountered.
+Error processCustomEventMarker(FDRState &State, uint8_t RecordFirstByte,
+                               DataExtractor &RecordExtractor,
+                               size_t &RecordSize) {
+  // We can encounter a CustomEventMarker anywhere in the log, so we can handle
+  // it regardless of the expectation. However, we do se the expectation to read
+  // a set number of fixed bytes, as described in the metadata.
+  uint32_t OffsetPtr = 1; // Read after the first byte.
+  uint32_t DataSize = RecordExtractor.getU32(&OffsetPtr);
+  uint64_t TSC = RecordExtractor.getU64(&OffsetPtr);
+
+  // FIXME: Actually represent the record through the API. For now we only skip
+  // through the data.
+  (void)TSC;
+  RecordSize = 16 + DataSize;
+  return Error::success();
+}
+
+/// Advances the state machine for reading the FDR record type by reading one
+/// Metadata Record and updating the State appropriately based on the kind of
+/// record encountered. The RecordKind is encoded in the first byte of the
+/// Record, which the caller should pass in because they have already read it
+/// to determine that this is a metadata record as opposed to a function record.
+Error processFDRMetadataRecord(FDRState &State, uint8_t RecordFirstByte,
+                               DataExtractor &RecordExtractor,
+                               size_t &RecordSize) {
+  // The remaining 7 bits are the RecordKind enum.
+  uint8_t RecordKind = RecordFirstByte >> 1;
+  switch (RecordKind) {
+  case 0: // NewBuffer
+    if (auto E =
+            processFDRNewBufferRecord(State, RecordFirstByte, RecordExtractor))
+      return E;
+    break;
+  case 1: // EndOfBuffer
+    if (auto E = processFDREndOfBufferRecord(State, RecordFirstByte,
+                                             RecordExtractor))
+      return E;
+    break;
+  case 2: // NewCPUId
+    if (auto E =
+            processFDRNewCPUIdRecord(State, RecordFirstByte, RecordExtractor))
+      return E;
+    break;
+  case 3: // TSCWrap
+    if (auto E =
+            processFDRTSCWrapRecord(State, RecordFirstByte, RecordExtractor))
+      return E;
+    break;
+  case 4: // WallTimeMarker
+    if (auto E =
+            processFDRWallTimeRecord(State, RecordFirstByte, RecordExtractor))
+      return E;
+    break;
+  case 5: // CustomEventMarker
+    if (auto E = processCustomEventMarker(State, RecordFirstByte,
+                                          RecordExtractor, RecordSize))
+      return E;
+    break;
+  default:
+    // Widen the record type to uint16_t to prevent conversion to char.
+    return make_error<StringError>(
+        Twine("Illegal metadata record type: ")
+            .concat(Twine(static_cast<unsigned>(RecordKind))),
+        std::make_error_code(std::errc::executable_format_error));
+  }
+  return Error::success();
+}
+
+/// Reads a function record from an FDR format log, appending a new XRayRecord
+/// to the vector being populated and updating the State with a new value
+/// reference value to interpret TSC deltas.
+///
+/// The XRayRecord constructed includes information from the function record
+/// processed here as well as Thread ID and CPU ID formerly extracted into
+/// State.
+Error processFDRFunctionRecord(FDRState &State, uint8_t RecordFirstByte,
+                               DataExtractor &RecordExtractor,
+                               std::vector<XRayRecord> &Records) {
+  switch (State.Expects) {
+  case FDRState::Token::NEW_BUFFER_RECORD_OR_EOF:
+    return make_error<StringError>(
+        "Malformed log. Received Function Record before new buffer setup.",
+        std::make_error_code(std::errc::executable_format_error));
+  case FDRState::Token::WALLCLOCK_RECORD:
+    return make_error<StringError>(
+        "Malformed log. Received Function Record when expecting wallclock.",
+        std::make_error_code(std::errc::executable_format_error));
+  case FDRState::Token::NEW_CPU_ID_RECORD:
+    return make_error<StringError>(
+        "Malformed log. Received Function Record before first CPU record.",
+        std::make_error_code(std::errc::executable_format_error));
+  default:
+    Records.emplace_back();
+    auto &Record = Records.back();
+    Record.RecordType = 0; // Record is type NORMAL.
+    // Strip off record type bit and use the next three bits.
+    uint8_t RecordType = (RecordFirstByte >> 1) & 0x07;
+    switch (RecordType) {
+    case static_cast<uint8_t>(RecordTypes::ENTER):
+      Record.Type = RecordTypes::ENTER;
+      break;
+    case static_cast<uint8_t>(RecordTypes::EXIT):
+    case 2: // TAIL_EXIT is not yet defined in RecordTypes.
+      Record.Type = RecordTypes::EXIT;
+      break;
+    default:
+      // When initializing the error, convert to uint16_t so that the record
+      // type isn't interpreted as a char.
+      return make_error<StringError>(
+          Twine("Illegal function record type: ")
+              .concat(Twine(static_cast<unsigned>(RecordType))),
+          std::make_error_code(std::errc::executable_format_error));
+    }
+    Record.CPU = State.CPUId;
+    Record.TId = State.ThreadId;
+    // Back up to read first 32 bits, including the 8 we pulled RecordType
+    // and RecordKind out of. The remaining 28 are FunctionId.
+    uint32_t OffsetPtr = 0;
+    // Despite function Id being a signed int on XRayRecord,
+    // when it is written to an FDR format, the top bits are truncated,
+    // so it is effectively an unsigned value. When we shift off the
+    // top four bits, we want the shift to be logical, so we read as
+    // uint32_t.
+    uint32_t FuncIdBitField = RecordExtractor.getU32(&OffsetPtr);
+    Record.FuncId = FuncIdBitField >> 4;
+    // FunctionRecords have a 32 bit delta from the previous absolute TSC
+    // or TSC delta. If this would overflow, we should read a TSCWrap record
+    // with an absolute TSC reading.
+    uint64_t new_tsc = State.BaseTSC + RecordExtractor.getU32(&OffsetPtr);
+    State.BaseTSC = new_tsc;
+    Record.TSC = new_tsc;
+  }
+  return Error::success();
+}
+
+/// Reads a log in FDR mode for version 1 of this binary format. FDR mode is
+/// defined as part of the compiler-rt project in xray_fdr_logging.h, and such
+/// a log consists of the familiar 32 bit XRayHeader, followed by sequences of
+/// of interspersed 16 byte Metadata Records and 8 byte Function Records.
+///
+/// The following is an attempt to document the grammar of the format, which is
+/// parsed by this function for little-endian machines. Since the format makes
+/// use of BitFields, when we support big-Endian architectures, we will need to
+/// adjust not only the endianness parameter to llvm's RecordExtractor, but also
+/// the bit twiddling logic, which is consistent with the little-endian
+/// convention that BitFields within a struct will first be packed into the
+/// least significant bits the address they belong to.
+///
+/// We expect a format complying with the grammar in the following pseudo-EBNF.
+///
+/// FDRLog: XRayFileHeader ThreadBuffer*
+/// XRayFileHeader: 32 bits to identify the log as FDR with machine metadata.
+/// ThreadBuffer: BufSize NewBuffer WallClockTime NewCPUId FunctionSequence EOB
+/// BufSize: 8 byte unsigned integer indicating how large the buffer is.
+/// NewBuffer: 16 byte metadata record with Thread Id.
+/// WallClockTime: 16 byte metadata record with human readable time.
+/// NewCPUId: 16 byte metadata record with CPUId and a 64 bit TSC reading.
+/// EOB: 16 byte record in a thread buffer plus mem garbage to fill BufSize.
+/// FunctionSequence: NewCPUId | TSCWrap | FunctionRecord
+/// TSCWrap: 16 byte metadata record with a full 64 bit TSC reading.
+/// FunctionRecord: 8 byte record with FunctionId, entry/exit, and TSC delta.
+Error loadFDRLog(StringRef Data, XRayFileHeader &FileHeader,
+                 std::vector<XRayRecord> &Records) {
+  if (Data.size() < 32)
+    return make_error<StringError>(
+        "Not enough bytes for an XRay log.",
+        std::make_error_code(std::errc::invalid_argument));
+
+  // For an FDR log, there are records sized 16 and 8 bytes.
+  // There actually may be no records if no non-trivial functions are
+  // instrumented.
+  if (Data.size() % 8 != 0)
+    return make_error<StringError>(
+        "Invalid-sized XRay data.",
+        std::make_error_code(std::errc::invalid_argument));
+
+  if (auto E = readBinaryFormatHeader(Data, FileHeader))
+    return E;
+
+  uint64_t BufferSize = 0;
+  {
+    StringRef ExtraDataRef(FileHeader.FreeFormData, 16);
+    DataExtractor ExtraDataExtractor(ExtraDataRef, true, 8);
+    uint32_t ExtraDataOffset = 0;
+    BufferSize = ExtraDataExtractor.getU64(&ExtraDataOffset);
+  }
+  FDRState State{0,          0, 0, FDRState::Token::NEW_BUFFER_RECORD_OR_EOF,
+                 BufferSize, 0};
+  // RecordSize will tell the loop how far to seek ahead based on the record
+  // type that we have just read.
+  size_t RecordSize = 0;
+  for (auto S = Data.drop_front(32); !S.empty(); S = S.drop_front(RecordSize)) {
+    DataExtractor RecordExtractor(S, true, 8);
+    uint32_t OffsetPtr = 0;
+    if (State.Expects == FDRState::Token::SCAN_TO_END_OF_THREAD_BUF) {
+      RecordSize = State.CurrentBufferSize - State.CurrentBufferConsumed;
+      if (S.size() < State.CurrentBufferSize - State.CurrentBufferConsumed) {
+        return make_error<StringError>(
+            Twine("Incomplete thread buffer. Expected ") +
+                Twine(State.CurrentBufferSize - State.CurrentBufferConsumed) +
+                " remaining bytes but found " + Twine(S.size()),
+            make_error_code(std::errc::invalid_argument));
+      }
+      State.CurrentBufferConsumed = 0;
+      State.Expects = FDRState::Token::NEW_BUFFER_RECORD_OR_EOF;
+      continue;
+    }
+    uint8_t BitField = RecordExtractor.getU8(&OffsetPtr);
+    bool isMetadataRecord = BitField & 0x01uL;
+    if (isMetadataRecord) {
+      RecordSize = 16;
+      if (auto E = processFDRMetadataRecord(State, BitField, RecordExtractor,
+                                            RecordSize))
+        return E;
+      State.CurrentBufferConsumed += RecordSize;
+    } else { // Process Function Record
+      RecordSize = 8;
+      if (auto E = processFDRFunctionRecord(State, BitField, RecordExtractor,
+                                            Records))
+        return E;
+      State.CurrentBufferConsumed += RecordSize;
+    }
+  }
+  // There are two conditions
+  if (State.Expects != FDRState::Token::NEW_BUFFER_RECORD_OR_EOF &&
+      !(State.Expects == FDRState::Token::SCAN_TO_END_OF_THREAD_BUF &&
+        State.CurrentBufferSize == State.CurrentBufferConsumed))
+    return make_error<StringError>(
+        Twine("Encountered EOF with unexpected state expectation ") +
+            fdrStateToTwine(State.Expects) +
+            ". Remaining expected bytes in thread buffer total " +
+            Twine(State.CurrentBufferSize - State.CurrentBufferConsumed),
+        std::make_error_code(std::errc::executable_format_error));
+
+  return Error::success();
+}
 
+Error loadYAMLLog(StringRef Data, XRayFileHeader &FileHeader,
+                  std::vector<XRayRecord> &Records) {
   // Load the documents from the MappedFile.
   YAMLXRayTrace Trace;
   Input In(Data);
@@ -175,14 +531,21 @@ Expected<Trace> llvm::xray::loadTraceFile(StringRef Filename, bool Sort) {
   uint16_t Version = HeaderExtractor.getU16(&OffsetPtr);
   uint16_t Type = HeaderExtractor.getU16(&OffsetPtr);
 
+  enum BinaryFormatType { NAIVE_FORMAT = 0, FLIGHT_DATA_RECORDER_FORMAT = 1 };
+
   Trace T;
-  if (Version == 1 && (Type == 0 || Type == 1)) {
-    if (auto E = NaiveLogLoader(StringRef(MappedFile.data(), MappedFile.size()),
-                                T.FileHeader, T.Records))
+  if (Version == 1 && Type == NAIVE_FORMAT) {
+    if (auto E =
+            loadNaiveFormatLog(StringRef(MappedFile.data(), MappedFile.size()),
+                               T.FileHeader, T.Records))
+      return std::move(E);
+  } else if (Version == 1 && Type == FLIGHT_DATA_RECORDER_FORMAT) {
+    if (auto E = loadFDRLog(StringRef(MappedFile.data(), MappedFile.size()),
+                            T.FileHeader, T.Records))
       return std::move(E);
   } else {
-    if (auto E = YAMLLogLoader(StringRef(MappedFile.data(), MappedFile.size()),
-                               T.FileHeader, T.Records))
+    if (auto E = loadYAMLLog(StringRef(MappedFile.data(), MappedFile.size()),
+                             T.FileHeader, T.Records))
       return std::move(E);
   }