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)

8 files changed, 1610 insertions, 1068 deletions

diff --git a/contrib/llvm/lib/Bitcode/Reader/BitcodeReader.cpp b/contrib/llvm/lib/Bitcode/Reader/BitcodeReader.cpp
index a46e49c..2b4970a 100644
--- a/contrib/llvm/lib/Bitcode/Reader/BitcodeReader.cpp
+++ b/contrib/llvm/lib/Bitcode/Reader/BitcodeReader.cpp
@@ -28,8 +28,8 @@
 #include "llvm/IR/Attributes.h"
 #include "llvm/IR/AutoUpgrade.h"
 #include "llvm/IR/BasicBlock.h"
-#include "llvm/IR/CallingConv.h"
 #include "llvm/IR/CallSite.h"
+#include "llvm/IR/CallingConv.h"
 #include "llvm/IR/Comdat.h"
 #include "llvm/IR/Constant.h"
 #include "llvm/IR/Constants.h"
@@ -40,13 +40,13 @@
 #include "llvm/IR/DiagnosticInfo.h"
 #include "llvm/IR/DiagnosticPrinter.h"
 #include "llvm/IR/Function.h"
+#include "llvm/IR/GVMaterializer.h"
 #include "llvm/IR/GlobalAlias.h"
 #include "llvm/IR/GlobalIFunc.h"
 #include "llvm/IR/GlobalIndirectSymbol.h"
 #include "llvm/IR/GlobalObject.h"
 #include "llvm/IR/GlobalValue.h"
 #include "llvm/IR/GlobalVariable.h"
-#include "llvm/IR/GVMaterializer.h"
 #include "llvm/IR/InlineAsm.h"
 #include "llvm/IR/InstIterator.h"
 #include "llvm/IR/InstrTypes.h"
@@ -372,12 +372,26 @@ Expected<std::string> readTriple(BitstreamCursor &Stream) {
 
 class BitcodeReaderBase {
 protected:
-  BitcodeReaderBase(BitstreamCursor Stream) : Stream(std::move(Stream)) {
+  BitcodeReaderBase(BitstreamCursor Stream, StringRef Strtab)
+      : Stream(std::move(Stream)), Strtab(Strtab) {
     this->Stream.setBlockInfo(&BlockInfo);
   }
 
   BitstreamBlockInfo BlockInfo;
   BitstreamCursor Stream;
+  StringRef Strtab;
+
+  /// In version 2 of the bitcode we store names of global values and comdats in
+  /// a string table rather than in the VST.
+  bool UseStrtab = false;
+
+  Expected<unsigned> parseVersionRecord(ArrayRef<uint64_t> Record);
+
+  /// If this module uses a string table, pop the reference to the string table
+  /// and return the referenced string and the rest of the record. Otherwise
+  /// just return the record itself.
+  std::pair<StringRef, ArrayRef<uint64_t>>
+  readNameFromStrtab(ArrayRef<uint64_t> Record);
 
   bool readBlockInfo();
 
@@ -395,6 +409,27 @@ Error BitcodeReaderBase::error(const Twine &Message) {
   return ::error(FullMsg);
 }
 
+Expected<unsigned>
+BitcodeReaderBase::parseVersionRecord(ArrayRef<uint64_t> Record) {
+  if (Record.size() < 1)
+    return error("Invalid record");
+  unsigned ModuleVersion = Record[0];
+  if (ModuleVersion > 2)
+    return error("Invalid value");
+  UseStrtab = ModuleVersion >= 2;
+  return ModuleVersion;
+}
+
+std::pair<StringRef, ArrayRef<uint64_t>>
+BitcodeReaderBase::readNameFromStrtab(ArrayRef<uint64_t> Record) {
+  if (!UseStrtab)
+    return {"", Record};
+  // Invalid reference. Let the caller complain about the record being empty.
+  if (Record[0] + Record[1] > Strtab.size())
+    return {"", {}};
+  return {StringRef(Strtab.data() + Record[0], Record[1]), Record.slice(2)};
+}
+
 class BitcodeReader : public BitcodeReaderBase, public GVMaterializer {
   LLVMContext &Context;
   Module *TheModule = nullptr;
@@ -405,6 +440,9 @@ class BitcodeReader : public BitcodeReaderBase, public GVMaterializer {
   bool SeenValueSymbolTable = false;
   uint64_t VSTOffset = 0;
 
+  std::vector<std::string> SectionTable;
+  std::vector<std::string> GCTable;
+
   std::vector<Type*> TypeList;
   BitcodeReaderValueList ValueList;
   Optional<MetadataLoader> MDLoader;
@@ -419,10 +457,10 @@ class BitcodeReader : public BitcodeReaderBase, public GVMaterializer {
 
   /// The set of attributes by index.  Index zero in the file is for null, and
   /// is thus not represented here.  As such all indices are off by one.
-  std::vector<AttributeSet> MAttributes;
+  std::vector<AttributeList> MAttributes;
 
   /// The set of attribute groups.
-  std::map<unsigned, AttributeSet> MAttributeGroups;
+  std::map<unsigned, AttributeList> MAttributeGroups;
 
   /// While parsing a function body, this is a list of the basic blocks for the
   /// function.
@@ -475,10 +513,11 @@ class BitcodeReader : public BitcodeReaderBase, public GVMaterializer {
   TBAAVerifier TBAAVerifyHelper;
 
   std::vector<std::string> BundleTags;
+  SmallVector<SyncScope::ID, 8> SSIDs;
 
 public:
-  BitcodeReader(BitstreamCursor Stream, StringRef ProducerIdentification,
-                LLVMContext &Context);
+  BitcodeReader(BitstreamCursor Stream, StringRef Strtab,
+                StringRef ProducerIdentification, LLVMContext &Context);
 
   Error materializeForwardReferencedFunctions();
 
@@ -520,10 +559,10 @@ private:
     return FunctionBBs[ID];
   }
 
-  AttributeSet getAttributes(unsigned i) const {
+  AttributeList getAttributes(unsigned i) const {
     if (i-1 < MAttributes.size())
       return MAttributes[i-1];
-    return AttributeSet();
+    return AttributeList();
   }
 
   /// Read a value/type pair out of the specified record from slot 'Slot'.
@@ -598,15 +637,26 @@ private:
   Error parseAlignmentValue(uint64_t Exponent, unsigned &Alignment);
   Error parseAttrKind(uint64_t Code, Attribute::AttrKind *Kind);
   Error parseModule(uint64_t ResumeBit, bool ShouldLazyLoadMetadata = false);
+
+  Error parseComdatRecord(ArrayRef<uint64_t> Record);
+  Error parseGlobalVarRecord(ArrayRef<uint64_t> Record);
+  Error parseFunctionRecord(ArrayRef<uint64_t> Record);
+  Error parseGlobalIndirectSymbolRecord(unsigned BitCode,
+                                        ArrayRef<uint64_t> Record);
+
   Error parseAttributeBlock();
   Error parseAttributeGroupBlock();
   Error parseTypeTable();
   Error parseTypeTableBody();
   Error parseOperandBundleTags();
+  Error parseSyncScopeNames();
 
   Expected<Value *> recordValue(SmallVectorImpl<uint64_t> &Record,
                                 unsigned NameIndex, Triple &TT);
+  void setDeferredFunctionInfo(unsigned FuncBitcodeOffsetDelta, Function *F,
+                               ArrayRef<uint64_t> Record);
   Error parseValueSymbolTable(uint64_t Offset = 0);
+  Error parseGlobalValueSymbolTable();
   Error parseConstants();
   Error rememberAndSkipFunctionBodies();
   Error rememberAndSkipFunctionBody();
@@ -620,6 +670,8 @@ private:
   Error findFunctionInStream(
       Function *F,
       DenseMap<Function *, uint64_t>::iterator DeferredFunctionInfoIterator);
+
+  SyncScope::ID getDecodedSyncScopeID(unsigned Val);
 };
 
 /// Class to manage reading and parsing function summary index bitcode
@@ -639,15 +691,16 @@ class ModuleSummaryIndexBitcodeReader : public BitcodeReaderBase {
   /// Used to enable on-demand parsing of the VST.
   uint64_t VSTOffset = 0;
 
-  // Map to save ValueId to GUID association that was recorded in the
+  // Map to save ValueId to ValueInfo association that was recorded in the
   // ValueSymbolTable. It is used after the VST is parsed to convert
   // call graph edges read from the function summary from referencing
-  // callees by their ValueId to using the GUID instead, which is how
+  // callees by their ValueId to using the ValueInfo instead, which is how
   // they are recorded in the summary index being built.
-  // We save a second GUID which is the same as the first one, but ignoring the
-  // linkage, i.e. for value other than local linkage they are identical.
-  DenseMap<unsigned, std::pair<GlobalValue::GUID, GlobalValue::GUID>>
-      ValueIdToCallGraphGUIDMap;
+  // We save a GUID which refers to the same global as the ValueInfo, but
+  // ignoring the linkage, i.e. for values other than local linkage they are
+  // identical.
+  DenseMap<unsigned, std::pair<ValueInfo, GlobalValue::GUID>>
+      ValueIdToValueInfoMap;
 
   /// Map populated during module path string table parsing, from the
   /// module ID to a string reference owned by the index's module
@@ -658,13 +711,25 @@ class ModuleSummaryIndexBitcodeReader : public BitcodeReaderBase {
   /// Original source file name recorded in a bitcode record.
   std::string SourceFileName;
 
+  /// The string identifier given to this module by the client, normally the
+  /// path to the bitcode file.
+  StringRef ModulePath;
+
+  /// For per-module summary indexes, the unique numerical identifier given to
+  /// this module by the client.
+  unsigned ModuleId;
+
 public:
-  ModuleSummaryIndexBitcodeReader(
-      BitstreamCursor Stream, ModuleSummaryIndex &TheIndex);
+  ModuleSummaryIndexBitcodeReader(BitstreamCursor Stream, StringRef Strtab,
+                                  ModuleSummaryIndex &TheIndex,
+                                  StringRef ModulePath, unsigned ModuleId);
 
-  Error parseModule(StringRef ModulePath);
+  Error parseModule();
 
 private:
+  void setValueGUID(uint64_t ValueID, StringRef ValueName,
+                    GlobalValue::LinkageTypes Linkage,
+                    StringRef SourceFileName);
   Error parseValueSymbolTable(
       uint64_t Offset,
       DenseMap<unsigned, GlobalValue::LinkageTypes> &ValueIdToLinkageMap);
@@ -672,11 +737,13 @@ private:
   std::vector<FunctionSummary::EdgeTy> makeCallList(ArrayRef<uint64_t> Record,
                                                     bool IsOldProfileFormat,
                                                     bool HasProfile);
-  Error parseEntireSummary(StringRef ModulePath);
+  Error parseEntireSummary(unsigned ID);
   Error parseModuleStringTable();
 
-  std::pair<GlobalValue::GUID, GlobalValue::GUID>
-  getGUIDFromValueId(unsigned ValueId);
+  std::pair<ValueInfo, GlobalValue::GUID>
+  getValueInfoFromValueId(unsigned ValueId);
+
+  ModuleSummaryIndex::ModuleInfo *addThisModule();
 };
 
 } // end anonymous namespace
@@ -694,10 +761,10 @@ std::error_code llvm::errorToErrorCodeAndEmitErrors(LLVMContext &Ctx,
   return std::error_code();
 }
 
-BitcodeReader::BitcodeReader(BitstreamCursor Stream,
+BitcodeReader::BitcodeReader(BitstreamCursor Stream, StringRef Strtab,
                              StringRef ProducerIdentification,
                              LLVMContext &Context)
-    : BitcodeReaderBase(std::move(Stream)), Context(Context),
+    : BitcodeReaderBase(std::move(Stream), Strtab), Context(Context),
       ValueList(Context) {
   this->ProducerIdentification = ProducerIdentification;
 }
@@ -802,11 +869,11 @@ static GlobalValueSummary::GVFlags getDecodedGVSummaryFlags(uint64_t RawFlags,
   auto Linkage = GlobalValue::LinkageTypes(RawFlags & 0xF); // 4 bits
   RawFlags = RawFlags >> 4;
   bool NotEligibleToImport = (RawFlags & 0x1) || Version < 3;
-  // The LiveRoot flag wasn't introduced until version 3. For dead stripping
+  // The Live flag wasn't introduced until version 3. For dead stripping
   // to work correctly on earlier versions, we must conservatively treat all
   // values as live.
-  bool LiveRoot = (RawFlags & 0x2) || Version < 3;
-  return GlobalValueSummary::GVFlags(Linkage, NotEligibleToImport, LiveRoot);
+  bool Live = (RawFlags & 0x2) || Version < 3;
+  return GlobalValueSummary::GVFlags(Linkage, NotEligibleToImport, Live);
 }
 
 static GlobalValue::VisibilityTypes getDecodedVisibility(unsigned Val) {
@@ -935,14 +1002,6 @@ static AtomicOrdering getDecodedOrdering(unsigned Val) {
   }
 }
 
-static SynchronizationScope getDecodedSynchScope(unsigned Val) {
-  switch (Val) {
-  case bitc::SYNCHSCOPE_SINGLETHREAD: return SingleThread;
-  default: // Map unknown scopes to cross-thread.
-  case bitc::SYNCHSCOPE_CROSSTHREAD: return CrossThread;
-  }
-}
-
 static Comdat::SelectionKind getDecodedComdatSelectionKind(unsigned Val) {
   switch (Val) {
   default: // Map unknown selection kinds to any.
@@ -971,6 +1030,8 @@ static FastMathFlags getDecodedFastMathFlags(unsigned Val) {
     FMF.setNoSignedZeros();
   if (0 != (Val & FastMathFlags::AllowReciprocal))
     FMF.setAllowReciprocal();
+  if (0 != (Val & FastMathFlags::AllowContract))
+    FMF.setAllowContract(true);
   return FMF;
 }
 
@@ -1066,6 +1127,7 @@ static uint64_t getRawAttributeMask(Attribute::AttrKind Val) {
   case Attribute::SwiftSelf:       return 1ULL << 51;
   case Attribute::SwiftError:      return 1ULL << 52;
   case Attribute::WriteOnly:       return 1ULL << 53;
+  case Attribute::Speculatable:    return 1ULL << 54;
   case Attribute::Dereferenceable:
     llvm_unreachable("dereferenceable attribute not supported in raw format");
     break;
@@ -1132,7 +1194,7 @@ Error BitcodeReader::parseAttributeBlock() {
 
   SmallVector<uint64_t, 64> Record;
 
-  SmallVector<AttributeSet, 8> Attrs;
+  SmallVector<AttributeList, 8> Attrs;
 
   // Read all the records.
   while (true) {
@@ -1162,10 +1224,10 @@ Error BitcodeReader::parseAttributeBlock() {
       for (unsigned i = 0, e = Record.size(); i != e; i += 2) {
         AttrBuilder B;
         decodeLLVMAttributesForBitcode(B, Record[i+1]);
-        Attrs.push_back(AttributeSet::get(Context, Record[i], B));
+        Attrs.push_back(AttributeList::get(Context, Record[i], B));
       }
 
-      MAttributes.push_back(AttributeSet::get(Context, Attrs));
+      MAttributes.push_back(AttributeList::get(Context, Attrs));
       Attrs.clear();
       break;
     }
@@ -1173,7 +1235,7 @@ Error BitcodeReader::parseAttributeBlock() {
       for (unsigned i = 0, e = Record.size(); i != e; ++i)
         Attrs.push_back(MAttributeGroups[Record[i]]);
 
-      MAttributes.push_back(AttributeSet::get(Context, Attrs));
+      MAttributes.push_back(AttributeList::get(Context, Attrs));
       Attrs.clear();
       break;
     }
@@ -1262,6 +1324,8 @@ static Attribute::AttrKind getAttrFromCode(uint64_t Code) {
     return Attribute::ReturnsTwice;
   case bitc::ATTR_KIND_S_EXT:
     return Attribute::SExt;
+  case bitc::ATTR_KIND_SPECULATABLE:
+    return Attribute::Speculatable;
   case bitc::ATTR_KIND_STACK_ALIGNMENT:
     return Attribute::StackAlignment;
   case bitc::ATTR_KIND_STACK_PROTECT:
@@ -1391,7 +1455,7 @@ Error BitcodeReader::parseAttributeGroupBlock() {
         }
       }
 
-      MAttributeGroups[GrpID] = AttributeSet::get(Context, Idx, B);
+      MAttributeGroups[GrpID] = AttributeList::get(Context, Idx, B);
       break;
     }
     }
@@ -1677,6 +1741,44 @@ Error BitcodeReader::parseOperandBundleTags() {
   }
 }
 
+Error BitcodeReader::parseSyncScopeNames() {
+  if (Stream.EnterSubBlock(bitc::SYNC_SCOPE_NAMES_BLOCK_ID))
+    return error("Invalid record");
+
+  if (!SSIDs.empty())
+    return error("Invalid multiple synchronization scope names blocks");
+
+  SmallVector<uint64_t, 64> Record;
+  while (true) {
+    BitstreamEntry Entry = Stream.advanceSkippingSubblocks();
+    switch (Entry.Kind) {
+    case BitstreamEntry::SubBlock: // Handled for us already.
+    case BitstreamEntry::Error:
+      return error("Malformed block");
+    case BitstreamEntry::EndBlock:
+      if (SSIDs.empty())
+        return error("Invalid empty synchronization scope names block");
+      return Error::success();
+    case BitstreamEntry::Record:
+      // The interesting case.
+      break;
+    }
+
+    // Synchronization scope names are implicitly mapped to synchronization
+    // scope IDs by their order.
+
+    if (Stream.readRecord(Entry.ID, Record) != bitc::SYNC_SCOPE_NAME)
+      return error("Invalid record");
+
+    SmallString<16> SSN;
+    if (convertToString(Record, 0, SSN))
+      return error("Invalid record");
+
+    SSIDs.push_back(Context.getOrInsertSyncScopeID(SSN));
+    Record.clear();
+  }
+}
+
 /// Associate a value with its name from the given index in the provided record.
 Expected<Value *> BitcodeReader::recordValue(SmallVectorImpl<uint64_t> &Record,
                                              unsigned NameIndex, Triple &TT) {
@@ -1725,6 +1827,54 @@ static uint64_t jumpToValueSymbolTable(uint64_t Offset,
   return CurrentBit;
 }
 
+void BitcodeReader::setDeferredFunctionInfo(unsigned FuncBitcodeOffsetDelta,
+                                            Function *F,
+                                            ArrayRef<uint64_t> Record) {
+  // Note that we subtract 1 here because the offset is relative to one word
+  // before the start of the identification or module block, which was
+  // historically always the start of the regular bitcode header.
+  uint64_t FuncWordOffset = Record[1] - 1;
+  uint64_t FuncBitOffset = FuncWordOffset * 32;
+  DeferredFunctionInfo[F] = FuncBitOffset + FuncBitcodeOffsetDelta;
+  // Set the LastFunctionBlockBit to point to the last function block.
+  // Later when parsing is resumed after function materialization,
+  // we can simply skip that last function block.
+  if (FuncBitOffset > LastFunctionBlockBit)
+    LastFunctionBlockBit = FuncBitOffset;
+}
+
+/// Read a new-style GlobalValue symbol table.
+Error BitcodeReader::parseGlobalValueSymbolTable() {
+  unsigned FuncBitcodeOffsetDelta =
+      Stream.getAbbrevIDWidth() + bitc::BlockIDWidth;
+
+  if (Stream.EnterSubBlock(bitc::VALUE_SYMTAB_BLOCK_ID))
+    return error("Invalid record");
+
+  SmallVector<uint64_t, 64> Record;
+  while (true) {
+    BitstreamEntry Entry = Stream.advanceSkippingSubblocks();
+
+    switch (Entry.Kind) {
+    case BitstreamEntry::SubBlock:
+    case BitstreamEntry::Error:
+      return error("Malformed block");
+    case BitstreamEntry::EndBlock:
+      return Error::success();
+    case BitstreamEntry::Record:
+      break;
+    }
+
+    Record.clear();
+    switch (Stream.readRecord(Entry.ID, Record)) {
+    case bitc::VST_CODE_FNENTRY: // [valueid, offset]
+      setDeferredFunctionInfo(FuncBitcodeOffsetDelta,
+                              cast<Function>(ValueList[Record[0]]), Record);
+      break;
+    }
+  }
+}
+
 /// Parse the value symbol table at either the current parsing location or
 /// at the given bit offset if provided.
 Error BitcodeReader::parseValueSymbolTable(uint64_t Offset) {
@@ -1732,8 +1882,18 @@ Error BitcodeReader::parseValueSymbolTable(uint64_t Offset) {
   // Pass in the Offset to distinguish between calling for the module-level
   // VST (where we want to jump to the VST offset) and the function-level
   // VST (where we don't).
-  if (Offset > 0)
+  if (Offset > 0) {
     CurrentBit = jumpToValueSymbolTable(Offset, Stream);
+    // If this module uses a string table, read this as a module-level VST.
+    if (UseStrtab) {
+      if (Error Err = parseGlobalValueSymbolTable())
+        return Err;
+      Stream.JumpToBit(CurrentBit);
+      return Error::success();
+    }
+    // Otherwise, the VST will be in a similar format to a function-level VST,
+    // and will contain symbol names.
+  }
 
   // Compute the delta between the bitcode indices in the VST (the word offset
   // to the word-aligned ENTER_SUBBLOCK for the function block, and that
@@ -1794,29 +1954,10 @@ Error BitcodeReader::parseValueSymbolTable(uint64_t Offset) {
         return Err;
       Value *V = ValOrErr.get();
 
-      auto *GO = dyn_cast<GlobalObject>(V);
-      if (!GO) {
-        // If this is an alias, need to get the actual Function object
-        // it aliases, in order to set up the DeferredFunctionInfo entry below.
-        auto *GA = dyn_cast<GlobalAlias>(V);
-        if (GA)
-          GO = GA->getBaseObject();
-        assert(GO);
-      }
-
-      // Note that we subtract 1 here because the offset is relative to one word
-      // before the start of the identification or module block, which was
-      // historically always the start of the regular bitcode header.
-      uint64_t FuncWordOffset = Record[1] - 1;
-      Function *F = dyn_cast<Function>(GO);
-      assert(F);
-      uint64_t FuncBitOffset = FuncWordOffset * 32;
-      DeferredFunctionInfo[F] = FuncBitOffset + FuncBitcodeOffsetDelta;
-      // Set the LastFunctionBlockBit to point to the last function block.
-      // Later when parsing is resumed after function materialization,
-      // we can simply skip that last function block.
-      if (FuncBitOffset > LastFunctionBlockBit)
-        LastFunctionBlockBit = FuncBitOffset;
+      // Ignore function offsets emitted for aliases of functions in older
+      // versions of LLVM.
+      if (auto *F = dyn_cast<Function>(V))
+        setDeferredFunctionInfo(FuncBitcodeOffsetDelta, F, Record);
       break;
     }
     case bitc::VST_CODE_BBENTRY: {
@@ -2501,6 +2642,16 @@ Error BitcodeReader::materializeMetadata() {
     if (Error Err = MDLoader->parseModuleMetadata())
       return Err;
   }
+
+  // Upgrade "Linker Options" module flag to "llvm.linker.options" module-level
+  // metadata.
+  if (Metadata *Val = TheModule->getModuleFlag("Linker Options")) {
+    NamedMDNode *LinkerOpts =
+        TheModule->getOrInsertNamedMetadata("llvm.linker.options");
+    for (const MDOperand &MDOptions : cast<MDNode>(Val)->operands())
+      LinkerOpts->addOperand(cast<MDNode>(MDOptions));
+  }
+
   DeferredMetadataInfo.clear();
   return Error::success();
 }
@@ -2539,6 +2690,7 @@ Error BitcodeReader::globalCleanup() {
 
   // Look for intrinsic functions which need to be upgraded at some point
   for (Function &F : *TheModule) {
+    MDLoader->upgradeDebugIntrinsics(F);
     Function *NewFn;
     if (UpgradeIntrinsicFunction(&F, NewFn))
       UpgradedIntrinsics[&F] = NewFn;
@@ -2607,6 +2759,272 @@ bool BitcodeReaderBase::readBlockInfo() {
   return false;
 }
 
+Error BitcodeReader::parseComdatRecord(ArrayRef<uint64_t> Record) {
+  // v1: [selection_kind, name]
+  // v2: [strtab_offset, strtab_size, selection_kind]
+  StringRef Name;
+  std::tie(Name, Record) = readNameFromStrtab(Record);
+
+  if (Record.size() < 1)
+    return error("Invalid record");
+  Comdat::SelectionKind SK = getDecodedComdatSelectionKind(Record[0]);
+  std::string OldFormatName;
+  if (!UseStrtab) {
+    if (Record.size() < 2)
+      return error("Invalid record");
+    unsigned ComdatNameSize = Record[1];
+    OldFormatName.reserve(ComdatNameSize);
+    for (unsigned i = 0; i != ComdatNameSize; ++i)
+      OldFormatName += (char)Record[2 + i];
+    Name = OldFormatName;
+  }
+  Comdat *C = TheModule->getOrInsertComdat(Name);
+  C->setSelectionKind(SK);
+  ComdatList.push_back(C);
+  return Error::success();
+}
+
+Error BitcodeReader::parseGlobalVarRecord(ArrayRef<uint64_t> Record) {
+  // v1: [pointer type, isconst, initid, linkage, alignment, section,
+  // visibility, threadlocal, unnamed_addr, externally_initialized,
+  // dllstorageclass, comdat, attributes] (name in VST)
+  // v2: [strtab_offset, strtab_size, v1]
+  StringRef Name;
+  std::tie(Name, Record) = readNameFromStrtab(Record);
+
+  if (Record.size() < 6)
+    return error("Invalid record");
+  Type *Ty = getTypeByID(Record[0]);
+  if (!Ty)
+    return error("Invalid record");
+  bool isConstant = Record[1] & 1;
+  bool explicitType = Record[1] & 2;
+  unsigned AddressSpace;
+  if (explicitType) {
+    AddressSpace = Record[1] >> 2;
+  } else {
+    if (!Ty->isPointerTy())
+      return error("Invalid type for value");
+    AddressSpace = cast<PointerType>(Ty)->getAddressSpace();
+    Ty = cast<PointerType>(Ty)->getElementType();
+  }
+
+  uint64_t RawLinkage = Record[3];
+  GlobalValue::LinkageTypes Linkage = getDecodedLinkage(RawLinkage);
+  unsigned Alignment;
+  if (Error Err = parseAlignmentValue(Record[4], Alignment))
+    return Err;
+  std::string Section;
+  if (Record[5]) {
+    if (Record[5] - 1 >= SectionTable.size())
+      return error("Invalid ID");
+    Section = SectionTable[Record[5] - 1];
+  }
+  GlobalValue::VisibilityTypes Visibility = GlobalValue::DefaultVisibility;
+  // Local linkage must have default visibility.
+  if (Record.size() > 6 && !GlobalValue::isLocalLinkage(Linkage))
+    // FIXME: Change to an error if non-default in 4.0.
+    Visibility = getDecodedVisibility(Record[6]);
+
+  GlobalVariable::ThreadLocalMode TLM = GlobalVariable::NotThreadLocal;
+  if (Record.size() > 7)
+    TLM = getDecodedThreadLocalMode(Record[7]);
+
+  GlobalValue::UnnamedAddr UnnamedAddr = GlobalValue::UnnamedAddr::None;
+  if (Record.size() > 8)
+    UnnamedAddr = getDecodedUnnamedAddrType(Record[8]);
+
+  bool ExternallyInitialized = false;
+  if (Record.size() > 9)
+    ExternallyInitialized = Record[9];
+
+  GlobalVariable *NewGV =
+      new GlobalVariable(*TheModule, Ty, isConstant, Linkage, nullptr, Name,
+                         nullptr, TLM, AddressSpace, ExternallyInitialized);
+  NewGV->setAlignment(Alignment);
+  if (!Section.empty())
+    NewGV->setSection(Section);
+  NewGV->setVisibility(Visibility);
+  NewGV->setUnnamedAddr(UnnamedAddr);
+
+  if (Record.size() > 10)
+    NewGV->setDLLStorageClass(getDecodedDLLStorageClass(Record[10]));
+  else
+    upgradeDLLImportExportLinkage(NewGV, RawLinkage);
+
+  ValueList.push_back(NewGV);
+
+  // Remember which value to use for the global initializer.
+  if (unsigned InitID = Record[2])
+    GlobalInits.push_back(std::make_pair(NewGV, InitID - 1));
+
+  if (Record.size() > 11) {
+    if (unsigned ComdatID = Record[11]) {
+      if (ComdatID > ComdatList.size())
+        return error("Invalid global variable comdat ID");
+      NewGV->setComdat(ComdatList[ComdatID - 1]);
+    }
+  } else if (hasImplicitComdat(RawLinkage)) {
+    NewGV->setComdat(reinterpret_cast<Comdat *>(1));
+  }
+
+  if (Record.size() > 12) {
+    auto AS = getAttributes(Record[12]).getFnAttributes();
+    NewGV->setAttributes(AS);
+  }
+  return Error::success();
+}
+
+Error BitcodeReader::parseFunctionRecord(ArrayRef<uint64_t> Record) {
+  // v1: [type, callingconv, isproto, linkage, paramattr, alignment, section,
+  // visibility, gc, unnamed_addr, prologuedata, dllstorageclass, comdat,
+  // prefixdata] (name in VST)
+  // v2: [strtab_offset, strtab_size, v1]
+  StringRef Name;
+  std::tie(Name, Record) = readNameFromStrtab(Record);
+
+  if (Record.size() < 8)
+    return error("Invalid record");
+  Type *Ty = getTypeByID(Record[0]);
+  if (!Ty)
+    return error("Invalid record");
+  if (auto *PTy = dyn_cast<PointerType>(Ty))
+    Ty = PTy->getElementType();
+  auto *FTy = dyn_cast<FunctionType>(Ty);
+  if (!FTy)
+    return error("Invalid type for value");
+  auto CC = static_cast<CallingConv::ID>(Record[1]);
+  if (CC & ~CallingConv::MaxID)
+    return error("Invalid calling convention ID");
+
+  Function *Func =
+      Function::Create(FTy, GlobalValue::ExternalLinkage, Name, TheModule);
+
+  Func->setCallingConv(CC);
+  bool isProto = Record[2];
+  uint64_t RawLinkage = Record[3];
+  Func->setLinkage(getDecodedLinkage(RawLinkage));
+  Func->setAttributes(getAttributes(Record[4]));
+
+  unsigned Alignment;
+  if (Error Err = parseAlignmentValue(Record[5], Alignment))
+    return Err;
+  Func->setAlignment(Alignment);
+  if (Record[6]) {
+    if (Record[6] - 1 >= SectionTable.size())
+      return error("Invalid ID");
+    Func->setSection(SectionTable[Record[6] - 1]);
+  }
+  // Local linkage must have default visibility.
+  if (!Func->hasLocalLinkage())
+    // FIXME: Change to an error if non-default in 4.0.
+    Func->setVisibility(getDecodedVisibility(Record[7]));
+  if (Record.size() > 8 && Record[8]) {
+    if (Record[8] - 1 >= GCTable.size())
+      return error("Invalid ID");
+    Func->setGC(GCTable[Record[8] - 1]);
+  }
+  GlobalValue::UnnamedAddr UnnamedAddr = GlobalValue::UnnamedAddr::None;
+  if (Record.size() > 9)
+    UnnamedAddr = getDecodedUnnamedAddrType(Record[9]);
+  Func->setUnnamedAddr(UnnamedAddr);
+  if (Record.size() > 10 && Record[10] != 0)
+    FunctionPrologues.push_back(std::make_pair(Func, Record[10] - 1));
+
+  if (Record.size() > 11)
+    Func->setDLLStorageClass(getDecodedDLLStorageClass(Record[11]));
+  else
+    upgradeDLLImportExportLinkage(Func, RawLinkage);
+
+  if (Record.size() > 12) {
+    if (unsigned ComdatID = Record[12]) {
+      if (ComdatID > ComdatList.size())
+        return error("Invalid function comdat ID");
+      Func->setComdat(ComdatList[ComdatID - 1]);
+    }
+  } else if (hasImplicitComdat(RawLinkage)) {
+    Func->setComdat(reinterpret_cast<Comdat *>(1));
+  }
+
+  if (Record.size() > 13 && Record[13] != 0)
+    FunctionPrefixes.push_back(std::make_pair(Func, Record[13] - 1));
+
+  if (Record.size() > 14 && Record[14] != 0)
+    FunctionPersonalityFns.push_back(std::make_pair(Func, Record[14] - 1));
+
+  ValueList.push_back(Func);
+
+  // If this is a function with a body, remember the prototype we are
+  // creating now, so that we can match up the body with them later.
+  if (!isProto) {
+    Func->setIsMaterializable(true);
+    FunctionsWithBodies.push_back(Func);
+    DeferredFunctionInfo[Func] = 0;
+  }
+  return Error::success();
+}
+
+Error BitcodeReader::parseGlobalIndirectSymbolRecord(
+    unsigned BitCode, ArrayRef<uint64_t> Record) {
+  // v1 ALIAS_OLD: [alias type, aliasee val#, linkage] (name in VST)
+  // v1 ALIAS: [alias type, addrspace, aliasee val#, linkage, visibility,
+  // dllstorageclass] (name in VST)
+  // v1 IFUNC: [alias type, addrspace, aliasee val#, linkage,
+  // visibility, dllstorageclass] (name in VST)
+  // v2: [strtab_offset, strtab_size, v1]
+  StringRef Name;
+  std::tie(Name, Record) = readNameFromStrtab(Record);
+
+  bool NewRecord = BitCode != bitc::MODULE_CODE_ALIAS_OLD;
+  if (Record.size() < (3 + (unsigned)NewRecord))
+    return error("Invalid record");
+  unsigned OpNum = 0;
+  Type *Ty = getTypeByID(Record[OpNum++]);
+  if (!Ty)
+    return error("Invalid record");
+
+  unsigned AddrSpace;
+  if (!NewRecord) {
+    auto *PTy = dyn_cast<PointerType>(Ty);
+    if (!PTy)
+      return error("Invalid type for value");
+    Ty = PTy->getElementType();
+    AddrSpace = PTy->getAddressSpace();
+  } else {
+    AddrSpace = Record[OpNum++];
+  }
+
+  auto Val = Record[OpNum++];
+  auto Linkage = Record[OpNum++];
+  GlobalIndirectSymbol *NewGA;
+  if (BitCode == bitc::MODULE_CODE_ALIAS ||
+      BitCode == bitc::MODULE_CODE_ALIAS_OLD)
+    NewGA = GlobalAlias::create(Ty, AddrSpace, getDecodedLinkage(Linkage), Name,
+                                TheModule);
+  else
+    NewGA = GlobalIFunc::create(Ty, AddrSpace, getDecodedLinkage(Linkage), Name,
+                                nullptr, TheModule);
+  // Old bitcode files didn't have visibility field.
+  // Local linkage must have default visibility.
+  if (OpNum != Record.size()) {
+    auto VisInd = OpNum++;
+    if (!NewGA->hasLocalLinkage())
+      // FIXME: Change to an error if non-default in 4.0.
+      NewGA->setVisibility(getDecodedVisibility(Record[VisInd]));
+  }
+  if (OpNum != Record.size())
+    NewGA->setDLLStorageClass(getDecodedDLLStorageClass(Record[OpNum++]));
+  else
+    upgradeDLLImportExportLinkage(NewGA, Linkage);
+  if (OpNum != Record.size())
+    NewGA->setThreadLocalMode(getDecodedThreadLocalMode(Record[OpNum++]));
+  if (OpNum != Record.size())
+    NewGA->setUnnamedAddr(getDecodedUnnamedAddrType(Record[OpNum++]));
+  ValueList.push_back(NewGA);
+  IndirectSymbolInits.push_back(std::make_pair(NewGA, Val));
+  return Error::success();
+}
+
 Error BitcodeReader::parseModule(uint64_t ResumeBit,
                                  bool ShouldLazyLoadMetadata) {
   if (ResumeBit)
@@ -2615,8 +3033,6 @@ Error BitcodeReader::parseModule(uint64_t ResumeBit,
     return error("Invalid record");
 
   SmallVector<uint64_t, 64> Record;
-  std::vector<std::string> SectionTable;
-  std::vector<std::string> GCTable;
 
   // Read all the records for this module.
   while (true) {
@@ -2750,6 +3166,10 @@ Error BitcodeReader::parseModule(uint64_t ResumeBit,
         if (Error Err = parseOperandBundleTags())
           return Err;
         break;
+      case bitc::SYNC_SCOPE_NAMES_BLOCK_ID:
+        if (Error Err = parseSyncScopeNames())
+          return Err;
+        break;
       }
       continue;
 
@@ -2762,21 +3182,11 @@ Error BitcodeReader::parseModule(uint64_t ResumeBit,
     auto BitCode = Stream.readRecord(Entry.ID, Record);
     switch (BitCode) {
     default: break;  // Default behavior, ignore unknown content.
-    case bitc::MODULE_CODE_VERSION: {  // VERSION: [version#]
-      if (Record.size() < 1)
-        return error("Invalid record");
-      // Only version #0 and #1 are supported so far.
-      unsigned module_version = Record[0];
-      switch (module_version) {
-        default:
-          return error("Invalid value");
-        case 0:
-          UseRelativeIDs = false;
-          break;
-        case 1:
-          UseRelativeIDs = true;
-          break;
-      }
+    case bitc::MODULE_CODE_VERSION: {
+      Expected<unsigned> VersionOrErr = parseVersionRecord(Record);
+      if (!VersionOrErr)
+        return VersionOrErr.takeError();
+      UseRelativeIDs = *VersionOrErr >= 1;
       break;
     }
     case bitc::MODULE_CODE_TRIPLE: {  // TRIPLE: [strchr x N]
@@ -2822,249 +3232,28 @@ Error BitcodeReader::parseModule(uint64_t ResumeBit,
       GCTable.push_back(S);
       break;
     }
-    case bitc::MODULE_CODE_COMDAT: { // COMDAT: [selection_kind, name]
-      if (Record.size() < 2)
-        return error("Invalid record");
-      Comdat::SelectionKind SK = getDecodedComdatSelectionKind(Record[0]);
-      unsigned ComdatNameSize = Record[1];
-      std::string ComdatName;
-      ComdatName.reserve(ComdatNameSize);
-      for (unsigned i = 0; i != ComdatNameSize; ++i)
-        ComdatName += (char)Record[2 + i];
-      Comdat *C = TheModule->getOrInsertComdat(ComdatName);
-      C->setSelectionKind(SK);
-      ComdatList.push_back(C);
-      break;
-    }
-    // GLOBALVAR: [pointer type, isconst, initid,
-    //             linkage, alignment, section, visibility, threadlocal,
-    //             unnamed_addr, externally_initialized, dllstorageclass,
-    //             comdat]
+    case bitc::MODULE_CODE_COMDAT: {
+      if (Error Err = parseComdatRecord(Record))
+        return Err;
+      break;
+    }
     case bitc::MODULE_CODE_GLOBALVAR: {
-      if (Record.size() < 6)
-        return error("Invalid record");
-      Type *Ty = getTypeByID(Record[0]);
-      if (!Ty)
-        return error("Invalid record");
-      bool isConstant = Record[1] & 1;
-      bool explicitType = Record[1] & 2;
-      unsigned AddressSpace;
-      if (explicitType) {
-        AddressSpace = Record[1] >> 2;
-      } else {
-        if (!Ty->isPointerTy())
-          return error("Invalid type for value");
-        AddressSpace = cast<PointerType>(Ty)->getAddressSpace();
-        Ty = cast<PointerType>(Ty)->getElementType();
-      }
-
-      uint64_t RawLinkage = Record[3];
-      GlobalValue::LinkageTypes Linkage = getDecodedLinkage(RawLinkage);
-      unsigned Alignment;
-      if (Error Err = parseAlignmentValue(Record[4], Alignment))
+      if (Error Err = parseGlobalVarRecord(Record))
         return Err;
-      std::string Section;
-      if (Record[5]) {
-        if (Record[5]-1 >= SectionTable.size())
-          return error("Invalid ID");
-        Section = SectionTable[Record[5]-1];
-      }
-      GlobalValue::VisibilityTypes Visibility = GlobalValue::DefaultVisibility;
-      // Local linkage must have default visibility.
-      if (Record.size() > 6 && !GlobalValue::isLocalLinkage(Linkage))
-        // FIXME: Change to an error if non-default in 4.0.
-        Visibility = getDecodedVisibility(Record[6]);
-
-      GlobalVariable::ThreadLocalMode TLM = GlobalVariable::NotThreadLocal;
-      if (Record.size() > 7)
-        TLM = getDecodedThreadLocalMode(Record[7]);
-
-      GlobalValue::UnnamedAddr UnnamedAddr = GlobalValue::UnnamedAddr::None;
-      if (Record.size() > 8)
-        UnnamedAddr = getDecodedUnnamedAddrType(Record[8]);
-
-      bool ExternallyInitialized = false;
-      if (Record.size() > 9)
-        ExternallyInitialized = Record[9];
-
-      GlobalVariable *NewGV =
-        new GlobalVariable(*TheModule, Ty, isConstant, Linkage, nullptr, "", nullptr,
-                           TLM, AddressSpace, ExternallyInitialized);
-      NewGV->setAlignment(Alignment);
-      if (!Section.empty())
-        NewGV->setSection(Section);
-      NewGV->setVisibility(Visibility);
-      NewGV->setUnnamedAddr(UnnamedAddr);
-
-      if (Record.size() > 10)
-        NewGV->setDLLStorageClass(getDecodedDLLStorageClass(Record[10]));
-      else
-        upgradeDLLImportExportLinkage(NewGV, RawLinkage);
-
-      ValueList.push_back(NewGV);
-
-      // Remember which value to use for the global initializer.
-      if (unsigned InitID = Record[2])
-        GlobalInits.push_back(std::make_pair(NewGV, InitID-1));
-
-      if (Record.size() > 11) {
-        if (unsigned ComdatID = Record[11]) {
-          if (ComdatID > ComdatList.size())
-            return error("Invalid global variable comdat ID");
-          NewGV->setComdat(ComdatList[ComdatID - 1]);
-        }
-      } else if (hasImplicitComdat(RawLinkage)) {
-        NewGV->setComdat(reinterpret_cast<Comdat *>(1));
-      }
-
       break;
     }
-    // FUNCTION:  [type, callingconv, isproto, linkage, paramattr,
-    //             alignment, section, visibility, gc, unnamed_addr,
-    //             prologuedata, dllstorageclass, comdat, prefixdata]
     case bitc::MODULE_CODE_FUNCTION: {
-      if (Record.size() < 8)
-        return error("Invalid record");
-      Type *Ty = getTypeByID(Record[0]);
-      if (!Ty)
-        return error("Invalid record");
-      if (auto *PTy = dyn_cast<PointerType>(Ty))
-        Ty = PTy->getElementType();
-      auto *FTy = dyn_cast<FunctionType>(Ty);
-      if (!FTy)
-        return error("Invalid type for value");
-      auto CC = static_cast<CallingConv::ID>(Record[1]);
-      if (CC & ~CallingConv::MaxID)
-        return error("Invalid calling convention ID");
-
-      Function *Func = Function::Create(FTy, GlobalValue::ExternalLinkage,
-                                        "", TheModule);
-
-      Func->setCallingConv(CC);
-      bool isProto = Record[2];
-      uint64_t RawLinkage = Record[3];
-      Func->setLinkage(getDecodedLinkage(RawLinkage));
-      Func->setAttributes(getAttributes(Record[4]));
-
-      unsigned Alignment;
-      if (Error Err = parseAlignmentValue(Record[5], Alignment))
+      if (Error Err = parseFunctionRecord(Record))
         return Err;
-      Func->setAlignment(Alignment);
-      if (Record[6]) {
-        if (Record[6]-1 >= SectionTable.size())
-          return error("Invalid ID");
-        Func->setSection(SectionTable[Record[6]-1]);
-      }
-      // Local linkage must have default visibility.
-      if (!Func->hasLocalLinkage())
-        // FIXME: Change to an error if non-default in 4.0.
-        Func->setVisibility(getDecodedVisibility(Record[7]));
-      if (Record.size() > 8 && Record[8]) {
-        if (Record[8]-1 >= GCTable.size())
-          return error("Invalid ID");
-        Func->setGC(GCTable[Record[8] - 1]);
-      }
-      GlobalValue::UnnamedAddr UnnamedAddr = GlobalValue::UnnamedAddr::None;
-      if (Record.size() > 9)
-        UnnamedAddr = getDecodedUnnamedAddrType(Record[9]);
-      Func->setUnnamedAddr(UnnamedAddr);
-      if (Record.size() > 10 && Record[10] != 0)
-        FunctionPrologues.push_back(std::make_pair(Func, Record[10]-1));
-
-      if (Record.size() > 11)
-        Func->setDLLStorageClass(getDecodedDLLStorageClass(Record[11]));
-      else
-        upgradeDLLImportExportLinkage(Func, RawLinkage);
-
-      if (Record.size() > 12) {
-        if (unsigned ComdatID = Record[12]) {
-          if (ComdatID > ComdatList.size())
-            return error("Invalid function comdat ID");
-          Func->setComdat(ComdatList[ComdatID - 1]);
-        }
-      } else if (hasImplicitComdat(RawLinkage)) {
-        Func->setComdat(reinterpret_cast<Comdat *>(1));
-      }
-
-      if (Record.size() > 13 && Record[13] != 0)
-        FunctionPrefixes.push_back(std::make_pair(Func, Record[13]-1));
-
-      if (Record.size() > 14 && Record[14] != 0)
-        FunctionPersonalityFns.push_back(std::make_pair(Func, Record[14] - 1));
-
-      ValueList.push_back(Func);
-
-      // If this is a function with a body, remember the prototype we are
-      // creating now, so that we can match up the body with them later.
-      if (!isProto) {
-        Func->setIsMaterializable(true);
-        FunctionsWithBodies.push_back(Func);
-        DeferredFunctionInfo[Func] = 0;
-      }
       break;
     }
-    // ALIAS: [alias type, addrspace, aliasee val#, linkage]
-    // ALIAS: [alias type, addrspace, aliasee val#, linkage, visibility, dllstorageclass]
-    // IFUNC: [alias type, addrspace, aliasee val#, linkage, visibility, dllstorageclass]
     case bitc::MODULE_CODE_IFUNC:
     case bitc::MODULE_CODE_ALIAS:
     case bitc::MODULE_CODE_ALIAS_OLD: {
-      bool NewRecord = BitCode != bitc::MODULE_CODE_ALIAS_OLD;
-      if (Record.size() < (3 + (unsigned)NewRecord))
-        return error("Invalid record");
-      unsigned OpNum = 0;
-      Type *Ty = getTypeByID(Record[OpNum++]);
-      if (!Ty)
-        return error("Invalid record");
-
-      unsigned AddrSpace;
-      if (!NewRecord) {
-        auto *PTy = dyn_cast<PointerType>(Ty);
-        if (!PTy)
-          return error("Invalid type for value");
-        Ty = PTy->getElementType();
-        AddrSpace = PTy->getAddressSpace();
-      } else {
-        AddrSpace = Record[OpNum++];
-      }
-
-      auto Val = Record[OpNum++];
-      auto Linkage = Record[OpNum++];
-      GlobalIndirectSymbol *NewGA;
-      if (BitCode == bitc::MODULE_CODE_ALIAS ||
-          BitCode == bitc::MODULE_CODE_ALIAS_OLD)
-        NewGA = GlobalAlias::create(Ty, AddrSpace, getDecodedLinkage(Linkage),
-                                    "", TheModule);
-      else
-        NewGA = GlobalIFunc::create(Ty, AddrSpace, getDecodedLinkage(Linkage),
-                                    "", nullptr, TheModule);
-      // Old bitcode files didn't have visibility field.
-      // Local linkage must have default visibility.
-      if (OpNum != Record.size()) {
-        auto VisInd = OpNum++;
-        if (!NewGA->hasLocalLinkage())
-          // FIXME: Change to an error if non-default in 4.0.
-          NewGA->setVisibility(getDecodedVisibility(Record[VisInd]));
-      }
-      if (OpNum != Record.size())
-        NewGA->setDLLStorageClass(getDecodedDLLStorageClass(Record[OpNum++]));
-      else
-        upgradeDLLImportExportLinkage(NewGA, Linkage);
-      if (OpNum != Record.size())
-        NewGA->setThreadLocalMode(getDecodedThreadLocalMode(Record[OpNum++]));
-      if (OpNum != Record.size())
-        NewGA->setUnnamedAddr(getDecodedUnnamedAddrType(Record[OpNum++]));
-      ValueList.push_back(NewGA);
-      IndirectSymbolInits.push_back(std::make_pair(NewGA, Val));
-      break;
-    }
-    /// MODULE_CODE_PURGEVALS: [numvals]
-    case bitc::MODULE_CODE_PURGEVALS:
-      // Trim down the value list to the specified size.
-      if (Record.size() < 1 || Record[0] > ValueList.size())
-        return error("Invalid record");
-      ValueList.shrinkTo(Record[0]);
+      if (Error Err = parseGlobalIndirectSymbolRecord(BitCode, Record))
+        return Err;
       break;
+    }
     /// MODULE_CODE_VSTOFFSET: [offset]
     case bitc::MODULE_CODE_VSTOFFSET:
       if (Record.size() < 1)
@@ -3840,7 +4029,7 @@ Error BitcodeReader::parseFunctionBody(Function *F) {
       if (Record.size() < 4)
         return error("Invalid record");
       unsigned OpNum = 0;
-      AttributeSet PAL = getAttributes(Record[OpNum++]);
+      AttributeList PAL = getAttributes(Record[OpNum++]);
       unsigned CCInfo = Record[OpNum++];
       BasicBlock *NormalBB = getBasicBlock(Record[OpNum++]);
       BasicBlock *UnwindBB = getBasicBlock(Record[OpNum++]);
@@ -4017,7 +4206,12 @@ Error BitcodeReader::parseFunctionBody(Function *F) {
       }
       if (!Ty || !Size)
         return error("Invalid record");
-      AllocaInst *AI = new AllocaInst(Ty, Size, Align);
+
+      // FIXME: Make this an optional field.
+      const DataLayout &DL = TheModule->getDataLayout();
+      unsigned AS = DL.getAllocaAddrSpace();
+
+      AllocaInst *AI = new AllocaInst(Ty, AS, Size, Align);
       AI->setUsedWithInAlloca(InAlloca);
       AI->setSwiftError(SwiftError);
       I = AI;
@@ -4048,7 +4242,7 @@ Error BitcodeReader::parseFunctionBody(Function *F) {
       break;
     }
     case bitc::FUNC_CODE_INST_LOADATOMIC: {
-       // LOADATOMIC: [opty, op, align, vol, ordering, synchscope]
+       // LOADATOMIC: [opty, op, align, vol, ordering, ssid]
       unsigned OpNum = 0;
       Value *Op;
       if (getValueTypePair(Record, OpNum, NextValueNo, Op) ||
@@ -4070,12 +4264,12 @@ Error BitcodeReader::parseFunctionBody(Function *F) {
         return error("Invalid record");
       if (Ordering != AtomicOrdering::NotAtomic && Record[OpNum] == 0)
         return error("Invalid record");
-      SynchronizationScope SynchScope = getDecodedSynchScope(Record[OpNum + 3]);
+      SyncScope::ID SSID = getDecodedSyncScopeID(Record[OpNum + 3]);
 
       unsigned Align;
       if (Error Err = parseAlignmentValue(Record[OpNum], Align))
         return Err;
-      I = new LoadInst(Op, "", Record[OpNum+1], Align, Ordering, SynchScope);
+      I = new LoadInst(Op, "", Record[OpNum+1], Align, Ordering, SSID);
 
       InstructionList.push_back(I);
       break;
@@ -4104,7 +4298,7 @@ Error BitcodeReader::parseFunctionBody(Function *F) {
     }
     case bitc::FUNC_CODE_INST_STOREATOMIC:
     case bitc::FUNC_CODE_INST_STOREATOMIC_OLD: {
-      // STOREATOMIC: [ptrty, ptr, val, align, vol, ordering, synchscope]
+      // STOREATOMIC: [ptrty, ptr, val, align, vol, ordering, ssid]
       unsigned OpNum = 0;
       Value *Val, *Ptr;
       if (getValueTypePair(Record, OpNum, NextValueNo, Ptr) ||
@@ -4124,20 +4318,20 @@ Error BitcodeReader::parseFunctionBody(Function *F) {
           Ordering == AtomicOrdering::Acquire ||
           Ordering == AtomicOrdering::AcquireRelease)
         return error("Invalid record");
-      SynchronizationScope SynchScope = getDecodedSynchScope(Record[OpNum + 3]);
+      SyncScope::ID SSID = getDecodedSyncScopeID(Record[OpNum + 3]);
       if (Ordering != AtomicOrdering::NotAtomic && Record[OpNum] == 0)
         return error("Invalid record");
 
       unsigned Align;
       if (Error Err = parseAlignmentValue(Record[OpNum], Align))
         return Err;
-      I = new StoreInst(Val, Ptr, Record[OpNum+1], Align, Ordering, SynchScope);
+      I = new StoreInst(Val, Ptr, Record[OpNum+1], Align, Ordering, SSID);
       InstructionList.push_back(I);
       break;
     }
     case bitc::FUNC_CODE_INST_CMPXCHG_OLD:
     case bitc::FUNC_CODE_INST_CMPXCHG: {
-      // CMPXCHG:[ptrty, ptr, cmp, new, vol, successordering, synchscope,
+      // CMPXCHG:[ptrty, ptr, cmp, new, vol, successordering, ssid,
       //          failureordering?, isweak?]
       unsigned OpNum = 0;
       Value *Ptr, *Cmp, *New;
@@ -4154,7 +4348,7 @@ Error BitcodeReader::parseFunctionBody(Function *F) {
       if (SuccessOrdering == AtomicOrdering::NotAtomic ||
           SuccessOrdering == AtomicOrdering::Unordered)
         return error("Invalid record");
-      SynchronizationScope SynchScope = getDecodedSynchScope(Record[OpNum + 2]);
+      SyncScope::ID SSID = getDecodedSyncScopeID(Record[OpNum + 2]);
 
       if (Error Err = typeCheckLoadStoreInst(Cmp->getType(), Ptr->getType()))
         return Err;
@@ -4166,7 +4360,7 @@ Error BitcodeReader::parseFunctionBody(Function *F) {
         FailureOrdering = getDecodedOrdering(Record[OpNum + 3]);
 
       I = new AtomicCmpXchgInst(Ptr, Cmp, New, SuccessOrdering, FailureOrdering,
-                                SynchScope);
+                                SSID);
       cast<AtomicCmpXchgInst>(I)->setVolatile(Record[OpNum]);
 
       if (Record.size() < 8) {
@@ -4183,7 +4377,7 @@ Error BitcodeReader::parseFunctionBody(Function *F) {
       break;
     }
     case bitc::FUNC_CODE_INST_ATOMICRMW: {
-      // ATOMICRMW:[ptrty, ptr, val, op, vol, ordering, synchscope]
+      // ATOMICRMW:[ptrty, ptr, val, op, vol, ordering, ssid]
       unsigned OpNum = 0;
       Value *Ptr, *Val;
       if (getValueTypePair(Record, OpNum, NextValueNo, Ptr) ||
@@ -4200,13 +4394,13 @@ Error BitcodeReader::parseFunctionBody(Function *F) {
       if (Ordering == AtomicOrdering::NotAtomic ||
           Ordering == AtomicOrdering::Unordered)
         return error("Invalid record");
-      SynchronizationScope SynchScope = getDecodedSynchScope(Record[OpNum + 3]);
-      I = new AtomicRMWInst(Operation, Ptr, Val, Ordering, SynchScope);
+      SyncScope::ID SSID = getDecodedSyncScopeID(Record[OpNum + 3]);
+      I = new AtomicRMWInst(Operation, Ptr, Val, Ordering, SSID);
       cast<AtomicRMWInst>(I)->setVolatile(Record[OpNum+1]);
       InstructionList.push_back(I);
       break;
     }
-    case bitc::FUNC_CODE_INST_FENCE: { // FENCE:[ordering, synchscope]
+    case bitc::FUNC_CODE_INST_FENCE: { // FENCE:[ordering, ssid]
       if (2 != Record.size())
         return error("Invalid record");
       AtomicOrdering Ordering = getDecodedOrdering(Record[0]);
@@ -4214,8 +4408,8 @@ Error BitcodeReader::parseFunctionBody(Function *F) {
           Ordering == AtomicOrdering::Unordered ||
           Ordering == AtomicOrdering::Monotonic)
         return error("Invalid record");
-      SynchronizationScope SynchScope = getDecodedSynchScope(Record[1]);
-      I = new FenceInst(Context, Ordering, SynchScope);
+      SyncScope::ID SSID = getDecodedSyncScopeID(Record[1]);
+      I = new FenceInst(Context, Ordering, SSID);
       InstructionList.push_back(I);
       break;
     }
@@ -4225,7 +4419,7 @@ Error BitcodeReader::parseFunctionBody(Function *F) {
         return error("Invalid record");
 
       unsigned OpNum = 0;
-      AttributeSet PAL = getAttributes(Record[OpNum++]);
+      AttributeList PAL = getAttributes(Record[OpNum++]);
       unsigned CCInfo = Record[OpNum++];
 
       FastMathFlags FMF;
@@ -4343,11 +4537,11 @@ Error BitcodeReader::parseFunctionBody(Function *F) {
     // Add instruction to end of current BB.  If there is no current BB, reject
     // this file.
     if (!CurBB) {
-      delete I;
+      I->deleteValue();
       return error("Invalid instruction with no BB");
     }
     if (!OperandBundles.empty()) {
-      delete I;
+      I->deleteValue();
       return error("Operand bundles found with no consumer");
     }
     CurBB->getInstList().push_back(I);
@@ -4411,6 +4605,14 @@ Error BitcodeReader::findFunctionInStream(
   return Error::success();
 }
 
+SyncScope::ID BitcodeReader::getDecodedSyncScopeID(unsigned Val) {
+  if (Val == SyncScope::SingleThread || Val == SyncScope::System)
+    return SyncScope::ID(Val);
+  if (Val >= SSIDs.size())
+    return SyncScope::System; // Map unknown synchronization scopes to system.
+  return SSIDs[Val];
+}
+
 //===----------------------------------------------------------------------===//
 // GVMaterializer implementation
 //===----------------------------------------------------------------------===//
@@ -4540,14 +4742,37 @@ std::vector<StructType *> BitcodeReader::getIdentifiedStructTypes() const {
 }
 
 ModuleSummaryIndexBitcodeReader::ModuleSummaryIndexBitcodeReader(
-    BitstreamCursor Cursor, ModuleSummaryIndex &TheIndex)
-    : BitcodeReaderBase(std::move(Cursor)), TheIndex(TheIndex) {}
-
-std::pair<GlobalValue::GUID, GlobalValue::GUID>
-ModuleSummaryIndexBitcodeReader::getGUIDFromValueId(unsigned ValueId) {
-  auto VGI = ValueIdToCallGraphGUIDMap.find(ValueId);
-  assert(VGI != ValueIdToCallGraphGUIDMap.end());
-  return VGI->second;
+    BitstreamCursor Cursor, StringRef Strtab, ModuleSummaryIndex &TheIndex,
+    StringRef ModulePath, unsigned ModuleId)
+    : BitcodeReaderBase(std::move(Cursor), Strtab), TheIndex(TheIndex),
+      ModulePath(ModulePath), ModuleId(ModuleId) {}
+
+ModuleSummaryIndex::ModuleInfo *
+ModuleSummaryIndexBitcodeReader::addThisModule() {
+  return TheIndex.addModule(ModulePath, ModuleId);
+}
+
+std::pair<ValueInfo, GlobalValue::GUID>
+ModuleSummaryIndexBitcodeReader::getValueInfoFromValueId(unsigned ValueId) {
+  auto VGI = ValueIdToValueInfoMap[ValueId];
+  assert(VGI.first);
+  return VGI;
+}
+
+void ModuleSummaryIndexBitcodeReader::setValueGUID(
+    uint64_t ValueID, StringRef ValueName, GlobalValue::LinkageTypes Linkage,
+    StringRef SourceFileName) {
+  std::string GlobalId =
+      GlobalValue::getGlobalIdentifier(ValueName, Linkage, SourceFileName);
+  auto ValueGUID = GlobalValue::getGUID(GlobalId);
+  auto OriginalNameID = ValueGUID;
+  if (GlobalValue::isLocalLinkage(Linkage))
+    OriginalNameID = GlobalValue::getGUID(ValueName);
+  if (PrintSummaryGUIDs)
+    dbgs() << "GUID " << ValueGUID << "(" << OriginalNameID << ") is "
+           << ValueName << "\n";
+  ValueIdToValueInfoMap[ValueID] =
+      std::make_pair(TheIndex.getOrInsertValueInfo(ValueGUID), OriginalNameID);
 }
 
 // Specialized value symbol table parser used when reading module index
@@ -4556,6 +4781,10 @@ ModuleSummaryIndexBitcodeReader::getGUIDFromValueId(unsigned ValueId) {
 Error ModuleSummaryIndexBitcodeReader::parseValueSymbolTable(
     uint64_t Offset,
     DenseMap<unsigned, GlobalValue::LinkageTypes> &ValueIdToLinkageMap) {
+  // With a strtab the VST is not required to parse the summary.
+  if (UseStrtab)
+    return Error::success();
+
   assert(Offset > 0 && "Expected non-zero VST offset");
   uint64_t CurrentBit = jumpToValueSymbolTable(Offset, Stream);
 
@@ -4597,17 +4826,7 @@ Error ModuleSummaryIndexBitcodeReader::parseValueSymbolTable(
       assert(VLI != ValueIdToLinkageMap.end() &&
              "No linkage found for VST entry?");
       auto Linkage = VLI->second;
-      std::string GlobalId =
-          GlobalValue::getGlobalIdentifier(ValueName, Linkage, SourceFileName);
-      auto ValueGUID = GlobalValue::getGUID(GlobalId);
-      auto OriginalNameID = ValueGUID;
-      if (GlobalValue::isLocalLinkage(Linkage))
-        OriginalNameID = GlobalValue::getGUID(ValueName);
-      if (PrintSummaryGUIDs)
-        dbgs() << "GUID " << ValueGUID << "(" << OriginalNameID << ") is "
-               << ValueName << "\n";
-      ValueIdToCallGraphGUIDMap[ValueID] =
-          std::make_pair(ValueGUID, OriginalNameID);
+      setValueGUID(ValueID, ValueName, Linkage, SourceFileName);
       ValueName.clear();
       break;
     }
@@ -4621,18 +4840,7 @@ Error ModuleSummaryIndexBitcodeReader::parseValueSymbolTable(
       assert(VLI != ValueIdToLinkageMap.end() &&
              "No linkage found for VST entry?");
       auto Linkage = VLI->second;
-      std::string FunctionGlobalId = GlobalValue::getGlobalIdentifier(
-          ValueName, VLI->second, SourceFileName);
-      auto FunctionGUID = GlobalValue::getGUID(FunctionGlobalId);
-      auto OriginalNameID = FunctionGUID;
-      if (GlobalValue::isLocalLinkage(Linkage))
-        OriginalNameID = GlobalValue::getGUID(ValueName);
-      if (PrintSummaryGUIDs)
-        dbgs() << "GUID " << FunctionGUID << "(" << OriginalNameID << ") is "
-               << ValueName << "\n";
-      ValueIdToCallGraphGUIDMap[ValueID] =
-          std::make_pair(FunctionGUID, OriginalNameID);
-
+      setValueGUID(ValueID, ValueName, Linkage, SourceFileName);
       ValueName.clear();
       break;
     }
@@ -4642,7 +4850,8 @@ Error ModuleSummaryIndexBitcodeReader::parseValueSymbolTable(
       GlobalValue::GUID RefGUID = Record[1];
       // The "original name", which is the second value of the pair will be
       // overriden later by a FS_COMBINED_ORIGINAL_NAME in the combined index.
-      ValueIdToCallGraphGUIDMap[ValueID] = std::make_pair(RefGUID, RefGUID);
+      ValueIdToValueInfoMap[ValueID] =
+          std::make_pair(TheIndex.getOrInsertValueInfo(RefGUID), RefGUID);
       break;
     }
     }
@@ -4652,7 +4861,7 @@ Error ModuleSummaryIndexBitcodeReader::parseValueSymbolTable(
 // Parse just the blocks needed for building the index out of the module.
 // At the end of this routine the module Index is populated with a map
 // from global value id to GlobalValueSummary objects.
-Error ModuleSummaryIndexBitcodeReader::parseModule(StringRef ModulePath) {
+Error ModuleSummaryIndexBitcodeReader::parseModule() {
   if (Stream.EnterSubBlock(bitc::MODULE_BLOCK_ID))
     return error("Invalid record");
 
@@ -4691,6 +4900,7 @@ Error ModuleSummaryIndexBitcodeReader::parseModule(StringRef ModulePath) {
           return error("Invalid record");
         break;
       case bitc::GLOBALVAL_SUMMARY_BLOCK_ID:
+      case bitc::FULL_LTO_GLOBALVAL_SUMMARY_BLOCK_ID:
         assert(!SeenValueSymbolTable &&
                "Already read VST when parsing summary block?");
         // We might not have a VST if there were no values in the
@@ -4703,7 +4913,7 @@ Error ModuleSummaryIndexBitcodeReader::parseModule(StringRef ModulePath) {
           SeenValueSymbolTable = true;
         }
         SeenGlobalValSummary = true;
-        if (Error Err = parseEntireSummary(ModulePath))
+        if (Error Err = parseEntireSummary(Entry.ID))
           return Err;
         break;
       case bitc::MODULE_STRTAB_BLOCK_ID:
@@ -4719,6 +4929,11 @@ Error ModuleSummaryIndexBitcodeReader::parseModule(StringRef ModulePath) {
         switch (BitCode) {
         default:
           break; // Default behavior, ignore unknown content.
+        case bitc::MODULE_CODE_VERSION: {
+          if (Error Err = parseVersionRecord(Record).takeError())
+            return Err;
+          break;
+        }
         /// MODULE_CODE_SOURCE_FILENAME: [namechar x N]
         case bitc::MODULE_CODE_SOURCE_FILENAME: {
           SmallString<128> ValueName;
@@ -4731,12 +4946,7 @@ Error ModuleSummaryIndexBitcodeReader::parseModule(StringRef ModulePath) {
         case bitc::MODULE_CODE_HASH: {
           if (Record.size() != 5)
             return error("Invalid hash length " + Twine(Record.size()).str());
-          if (TheIndex.modulePaths().empty())
-            // We always seed the index with the module.
-            TheIndex.addModulePath(ModulePath, 0);
-          if (TheIndex.modulePaths().size() != 1)
-            return error("Don't expect multiple modules defined?");
-          auto &Hash = TheIndex.modulePaths().begin()->second.second;
+          auto &Hash = addThisModule()->second.second;
           int Pos = 0;
           for (auto &Val : Record) {
             assert(!(Val >> 32) && "Unexpected high bits set");
@@ -4753,37 +4963,26 @@ Error ModuleSummaryIndexBitcodeReader::parseModule(StringRef ModulePath) {
           // was historically always the start of the regular bitcode header.
           VSTOffset = Record[0] - 1;
           break;
-        // GLOBALVAR: [pointer type, isconst, initid,
-        //             linkage, alignment, section, visibility, threadlocal,
-        //             unnamed_addr, externally_initialized, dllstorageclass,
-        //             comdat]
-        case bitc::MODULE_CODE_GLOBALVAR: {
-          if (Record.size() < 6)
-            return error("Invalid record");
-          uint64_t RawLinkage = Record[3];
-          GlobalValue::LinkageTypes Linkage = getDecodedLinkage(RawLinkage);
-          ValueIdToLinkageMap[ValueId++] = Linkage;
-          break;
-        }
-        // FUNCTION:  [type, callingconv, isproto, linkage, paramattr,
-        //             alignment, section, visibility, gc, unnamed_addr,
-        //             prologuedata, dllstorageclass, comdat, prefixdata]
-        case bitc::MODULE_CODE_FUNCTION: {
-          if (Record.size() < 8)
-            return error("Invalid record");
-          uint64_t RawLinkage = Record[3];
-          GlobalValue::LinkageTypes Linkage = getDecodedLinkage(RawLinkage);
-          ValueIdToLinkageMap[ValueId++] = Linkage;
-          break;
-        }
-        // ALIAS: [alias type, addrspace, aliasee val#, linkage, visibility,
-        // dllstorageclass]
+        // v1 GLOBALVAR: [pointer type, isconst,     initid,       linkage, ...]
+        // v1 FUNCTION:  [type,         callingconv, isproto,      linkage, ...]
+        // v1 ALIAS:     [alias type,   addrspace,   aliasee val#, linkage, ...]
+        // v2: [strtab offset, strtab size, v1]
+        case bitc::MODULE_CODE_GLOBALVAR:
+        case bitc::MODULE_CODE_FUNCTION:
         case bitc::MODULE_CODE_ALIAS: {
-          if (Record.size() < 6)
+          StringRef Name;
+          ArrayRef<uint64_t> GVRecord;
+          std::tie(Name, GVRecord) = readNameFromStrtab(Record);
+          if (GVRecord.size() <= 3)
             return error("Invalid record");
-          uint64_t RawLinkage = Record[3];
+          uint64_t RawLinkage = GVRecord[3];
           GlobalValue::LinkageTypes Linkage = getDecodedLinkage(RawLinkage);
-          ValueIdToLinkageMap[ValueId++] = Linkage;
+          if (!UseStrtab) {
+            ValueIdToLinkageMap[ValueId++] = Linkage;
+            break;
+          }
+
+          setValueGUID(ValueId++, Name, Linkage, SourceFileName);
           break;
         }
         }
@@ -4798,7 +4997,7 @@ ModuleSummaryIndexBitcodeReader::makeRefList(ArrayRef<uint64_t> Record) {
   std::vector<ValueInfo> Ret;
   Ret.reserve(Record.size());
   for (uint64_t RefValueId : Record)
-    Ret.push_back(getGUIDFromValueId(RefValueId).first);
+    Ret.push_back(getValueInfoFromValueId(RefValueId).first);
   return Ret;
 }
 
@@ -4808,23 +5007,22 @@ std::vector<FunctionSummary::EdgeTy> ModuleSummaryIndexBitcodeReader::makeCallLi
   Ret.reserve(Record.size());
   for (unsigned I = 0, E = Record.size(); I != E; ++I) {
     CalleeInfo::HotnessType Hotness = CalleeInfo::HotnessType::Unknown;
-    GlobalValue::GUID CalleeGUID = getGUIDFromValueId(Record[I]).first;
+    ValueInfo Callee = getValueInfoFromValueId(Record[I]).first;
     if (IsOldProfileFormat) {
       I += 1; // Skip old callsitecount field
       if (HasProfile)
         I += 1; // Skip old profilecount field
     } else if (HasProfile)
       Hotness = static_cast<CalleeInfo::HotnessType>(Record[++I]);
-    Ret.push_back(FunctionSummary::EdgeTy{CalleeGUID, CalleeInfo{Hotness}});
+    Ret.push_back(FunctionSummary::EdgeTy{Callee, CalleeInfo{Hotness}});
   }
   return Ret;
 }
 
 // Eagerly parse the entire summary block. This populates the GlobalValueSummary
 // objects in the index.
-Error ModuleSummaryIndexBitcodeReader::parseEntireSummary(
-    StringRef ModulePath) {
-  if (Stream.EnterSubBlock(bitc::GLOBALVAL_SUMMARY_BLOCK_ID))
+Error ModuleSummaryIndexBitcodeReader::parseEntireSummary(unsigned ID) {
+  if (Stream.EnterSubBlock(ID))
     return error("Invalid record");
   SmallVector<uint64_t, 64> Record;
 
@@ -4846,8 +5044,16 @@ Error ModuleSummaryIndexBitcodeReader::parseEntireSummary(
   // Keep around the last seen summary to be used when we see an optional
   // "OriginalName" attachement.
   GlobalValueSummary *LastSeenSummary = nullptr;
-  bool Combined = false;
+  GlobalValue::GUID LastSeenGUID = 0;
+
+  // We can expect to see any number of type ID information records before
+  // each function summary records; these variables store the information
+  // collected so far so that it can be used to create the summary object.
   std::vector<GlobalValue::GUID> PendingTypeTests;
+  std::vector<FunctionSummary::VFuncId> PendingTypeTestAssumeVCalls,
+      PendingTypeCheckedLoadVCalls;
+  std::vector<FunctionSummary::ConstVCall> PendingTypeTestAssumeConstVCalls,
+      PendingTypeCheckedLoadConstVCalls;
 
   while (true) {
     BitstreamEntry Entry = Stream.advanceSkippingSubblocks();
@@ -4857,16 +5063,6 @@ Error ModuleSummaryIndexBitcodeReader::parseEntireSummary(
     case BitstreamEntry::Error:
       return error("Malformed block");
     case BitstreamEntry::EndBlock:
-      // For a per-module index, remove any entries that still have empty
-      // summaries. The VST parsing creates entries eagerly for all symbols,
-      // but not all have associated summaries (e.g. it doesn't know how to
-      // distinguish between VST_CODE_ENTRY for function declarations vs global
-      // variables with initializers that end up with a summary). Remove those
-      // entries now so that we don't need to rely on the combined index merger
-      // to clean them up (especially since that may not run for the first
-      // module's index if we merge into that).
-      if (!Combined)
-        TheIndex.removeEmptySummaryEntries();
       return Error::success();
     case BitstreamEntry::Record:
       // The interesting case.
@@ -4885,6 +5081,13 @@ Error ModuleSummaryIndexBitcodeReader::parseEntireSummary(
     switch (BitCode) {
     default: // Default behavior: ignore.
       break;
+    case bitc::FS_VALUE_GUID: { // [valueid, refguid]
+      uint64_t ValueID = Record[0];
+      GlobalValue::GUID RefGUID = Record[1];
+      ValueIdToValueInfoMap[ValueID] =
+          std::make_pair(TheIndex.getOrInsertValueInfo(RefGUID), RefGUID);
+      break;
+    }
     // FS_PERMODULE: [valueid, flags, instcount, numrefs, numrefs x valueid,
     //                n x (valueid)]
     // FS_PERMODULE_PROFILE: [valueid, flags, instcount, numrefs,
@@ -4914,12 +5117,19 @@ Error ModuleSummaryIndexBitcodeReader::parseEntireSummary(
           IsOldProfileFormat, HasProfile);
       auto FS = llvm::make_unique<FunctionSummary>(
           Flags, InstCount, std::move(Refs), std::move(Calls),
-          std::move(PendingTypeTests));
+          std::move(PendingTypeTests), std::move(PendingTypeTestAssumeVCalls),
+          std::move(PendingTypeCheckedLoadVCalls),
+          std::move(PendingTypeTestAssumeConstVCalls),
+          std::move(PendingTypeCheckedLoadConstVCalls));
       PendingTypeTests.clear();
-      auto GUID = getGUIDFromValueId(ValueID);
-      FS->setModulePath(TheIndex.addModulePath(ModulePath, 0)->first());
-      FS->setOriginalName(GUID.second);
-      TheIndex.addGlobalValueSummary(GUID.first, std::move(FS));
+      PendingTypeTestAssumeVCalls.clear();
+      PendingTypeCheckedLoadVCalls.clear();
+      PendingTypeTestAssumeConstVCalls.clear();
+      PendingTypeCheckedLoadConstVCalls.clear();
+      auto VIAndOriginalGUID = getValueInfoFromValueId(ValueID);
+      FS->setModulePath(addThisModule()->first());
+      FS->setOriginalName(VIAndOriginalGUID.second);
+      TheIndex.addGlobalValueSummary(VIAndOriginalGUID.first, std::move(FS));
       break;
     }
     // FS_ALIAS: [valueid, flags, valueid]
@@ -4937,15 +5147,17 @@ Error ModuleSummaryIndexBitcodeReader::parseEntireSummary(
       // string table section in the per-module index, we create a single
       // module path string table entry with an empty (0) ID to take
       // ownership.
-      AS->setModulePath(TheIndex.addModulePath(ModulePath, 0)->first());
+      AS->setModulePath(addThisModule()->first());
 
-      GlobalValue::GUID AliaseeGUID = getGUIDFromValueId(AliaseeID).first;
-      auto *AliaseeSummary = TheIndex.getGlobalValueSummary(AliaseeGUID);
-      if (!AliaseeSummary)
+      GlobalValue::GUID AliaseeGUID =
+          getValueInfoFromValueId(AliaseeID).first.getGUID();
+      auto AliaseeInModule =
+          TheIndex.findSummaryInModule(AliaseeGUID, ModulePath);
+      if (!AliaseeInModule)
         return error("Alias expects aliasee summary to be parsed");
-      AS->setAliasee(AliaseeSummary);
+      AS->setAliasee(AliaseeInModule);
 
-      auto GUID = getGUIDFromValueId(ValueID);
+      auto GUID = getValueInfoFromValueId(ValueID);
       AS->setOriginalName(GUID.second);
       TheIndex.addGlobalValueSummary(GUID.first, std::move(AS));
       break;
@@ -4958,8 +5170,8 @@ Error ModuleSummaryIndexBitcodeReader::parseEntireSummary(
       std::vector<ValueInfo> Refs =
           makeRefList(ArrayRef<uint64_t>(Record).slice(2));
       auto FS = llvm::make_unique<GlobalVarSummary>(Flags, std::move(Refs));
-      FS->setModulePath(TheIndex.addModulePath(ModulePath, 0)->first());
-      auto GUID = getGUIDFromValueId(ValueID);
+      FS->setModulePath(addThisModule()->first());
+      auto GUID = getValueInfoFromValueId(ValueID);
       FS->setOriginalName(GUID.second);
       TheIndex.addGlobalValueSummary(GUID.first, std::move(FS));
       break;
@@ -4986,15 +5198,22 @@ Error ModuleSummaryIndexBitcodeReader::parseEntireSummary(
       std::vector<FunctionSummary::EdgeTy> Edges = makeCallList(
           ArrayRef<uint64_t>(Record).slice(CallGraphEdgeStartIndex),
           IsOldProfileFormat, HasProfile);
-      GlobalValue::GUID GUID = getGUIDFromValueId(ValueID).first;
+      ValueInfo VI = getValueInfoFromValueId(ValueID).first;
       auto FS = llvm::make_unique<FunctionSummary>(
           Flags, InstCount, std::move(Refs), std::move(Edges),
-          std::move(PendingTypeTests));
+          std::move(PendingTypeTests), std::move(PendingTypeTestAssumeVCalls),
+          std::move(PendingTypeCheckedLoadVCalls),
+          std::move(PendingTypeTestAssumeConstVCalls),
+          std::move(PendingTypeCheckedLoadConstVCalls));
       PendingTypeTests.clear();
+      PendingTypeTestAssumeVCalls.clear();
+      PendingTypeCheckedLoadVCalls.clear();
+      PendingTypeTestAssumeConstVCalls.clear();
+      PendingTypeCheckedLoadConstVCalls.clear();
       LastSeenSummary = FS.get();
+      LastSeenGUID = VI.getGUID();
       FS->setModulePath(ModuleIdMap[ModuleId]);
-      TheIndex.addGlobalValueSummary(GUID, std::move(FS));
-      Combined = true;
+      TheIndex.addGlobalValueSummary(VI, std::move(FS));
       break;
     }
     // FS_COMBINED_ALIAS: [valueid, modid, flags, valueid]
@@ -5010,16 +5229,17 @@ Error ModuleSummaryIndexBitcodeReader::parseEntireSummary(
       LastSeenSummary = AS.get();
       AS->setModulePath(ModuleIdMap[ModuleId]);
 
-      auto AliaseeGUID = getGUIDFromValueId(AliaseeValueId).first;
+      auto AliaseeGUID =
+          getValueInfoFromValueId(AliaseeValueId).first.getGUID();
       auto AliaseeInModule =
           TheIndex.findSummaryInModule(AliaseeGUID, AS->modulePath());
       if (!AliaseeInModule)
         return error("Alias expects aliasee summary to be parsed");
       AS->setAliasee(AliaseeInModule);
 
-      GlobalValue::GUID GUID = getGUIDFromValueId(ValueID).first;
-      TheIndex.addGlobalValueSummary(GUID, std::move(AS));
-      Combined = true;
+      ValueInfo VI = getValueInfoFromValueId(ValueID).first;
+      LastSeenGUID = VI.getGUID();
+      TheIndex.addGlobalValueSummary(VI, std::move(AS));
       break;
     }
     // FS_COMBINED_GLOBALVAR_INIT_REFS: [valueid, modid, flags, n x valueid]
@@ -5033,9 +5253,9 @@ Error ModuleSummaryIndexBitcodeReader::parseEntireSummary(
       auto FS = llvm::make_unique<GlobalVarSummary>(Flags, std::move(Refs));
       LastSeenSummary = FS.get();
       FS->setModulePath(ModuleIdMap[ModuleId]);
-      GlobalValue::GUID GUID = getGUIDFromValueId(ValueID).first;
-      TheIndex.addGlobalValueSummary(GUID, std::move(FS));
-      Combined = true;
+      ValueInfo VI = getValueInfoFromValueId(ValueID).first;
+      LastSeenGUID = VI.getGUID();
+      TheIndex.addGlobalValueSummary(VI, std::move(FS));
       break;
     }
     // FS_COMBINED_ORIGINAL_NAME: [original_name]
@@ -5044,8 +5264,10 @@ Error ModuleSummaryIndexBitcodeReader::parseEntireSummary(
       if (!LastSeenSummary)
         return error("Name attachment that does not follow a combined record");
       LastSeenSummary->setOriginalName(OriginalName);
+      TheIndex.addOriginalName(LastSeenGUID, OriginalName);
       // Reset the LastSeenSummary
       LastSeenSummary = nullptr;
+      LastSeenGUID = 0;
       break;
     }
     case bitc::FS_TYPE_TESTS: {
@@ -5054,6 +5276,42 @@ Error ModuleSummaryIndexBitcodeReader::parseEntireSummary(
                               Record.end());
       break;
     }
+    case bitc::FS_TYPE_TEST_ASSUME_VCALLS: {
+      assert(PendingTypeTestAssumeVCalls.empty());
+      for (unsigned I = 0; I != Record.size(); I += 2)
+        PendingTypeTestAssumeVCalls.push_back({Record[I], Record[I+1]});
+      break;
+    }
+    case bitc::FS_TYPE_CHECKED_LOAD_VCALLS: {
+      assert(PendingTypeCheckedLoadVCalls.empty());
+      for (unsigned I = 0; I != Record.size(); I += 2)
+        PendingTypeCheckedLoadVCalls.push_back({Record[I], Record[I+1]});
+      break;
+    }
+    case bitc::FS_TYPE_TEST_ASSUME_CONST_VCALL: {
+      PendingTypeTestAssumeConstVCalls.push_back(
+          {{Record[0], Record[1]}, {Record.begin() + 2, Record.end()}});
+      break;
+    }
+    case bitc::FS_TYPE_CHECKED_LOAD_CONST_VCALL: {
+      PendingTypeCheckedLoadConstVCalls.push_back(
+          {{Record[0], Record[1]}, {Record.begin() + 2, Record.end()}});
+      break;
+    }
+    case bitc::FS_CFI_FUNCTION_DEFS: {
+      std::set<std::string> &CfiFunctionDefs = TheIndex.cfiFunctionDefs();
+      for (unsigned I = 0; I != Record.size(); I += 2)
+        CfiFunctionDefs.insert(
+            {Strtab.data() + Record[I], static_cast<size_t>(Record[I + 1])});
+      break;
+    }
+    case bitc::FS_CFI_FUNCTION_DECLS: {
+      std::set<std::string> &CfiFunctionDecls = TheIndex.cfiFunctionDecls();
+      for (unsigned I = 0; I != Record.size(); I += 2)
+        CfiFunctionDecls.insert(
+            {Strtab.data() + Record[I], static_cast<size_t>(Record[I + 1])});
+      break;
+    }
     }
   }
   llvm_unreachable("Exit infinite loop");
@@ -5068,7 +5326,7 @@ Error ModuleSummaryIndexBitcodeReader::parseModuleStringTable() {
   SmallVector<uint64_t, 64> Record;
 
   SmallString<128> ModulePath;
-  ModulePathStringTableTy::iterator LastSeenModulePath;
+  ModuleSummaryIndex::ModuleInfo *LastSeenModule = nullptr;
 
   while (true) {
     BitstreamEntry Entry = Stream.advanceSkippingSubblocks();
@@ -5095,8 +5353,8 @@ Error ModuleSummaryIndexBitcodeReader::parseModuleStringTable() {
       if (convertToString(Record, 1, ModulePath))
         return error("Invalid record");
 
-      LastSeenModulePath = TheIndex.addModulePath(ModulePath, ModuleId);
-      ModuleIdMap[ModuleId] = LastSeenModulePath->first();
+      LastSeenModule = TheIndex.addModule(ModulePath, ModuleId);
+      ModuleIdMap[ModuleId] = LastSeenModule->first();
 
       ModulePath.clear();
       break;
@@ -5105,15 +5363,15 @@ Error ModuleSummaryIndexBitcodeReader::parseModuleStringTable() {
     case bitc::MST_CODE_HASH: {
       if (Record.size() != 5)
         return error("Invalid hash length " + Twine(Record.size()).str());
-      if (LastSeenModulePath == TheIndex.modulePaths().end())
+      if (!LastSeenModule)
         return error("Invalid hash that does not follow a module path");
       int Pos = 0;
       for (auto &Val : Record) {
         assert(!(Val >> 32) && "Unexpected high bits set");
-        LastSeenModulePath->second.second[Pos++] = Val;
+        LastSeenModule->second.second[Pos++] = Val;
       }
-      // Reset LastSeenModulePath to avoid overriding the hash unexpectedly.
-      LastSeenModulePath = TheIndex.modulePaths().end();
+      // Reset LastSeenModule to avoid overriding the hash unexpectedly.
+      LastSeenModule = nullptr;
       break;
     }
     }
@@ -5148,18 +5406,56 @@ const std::error_category &llvm::BitcodeErrorCategory() {
   return *ErrorCategory;
 }
 
+static Expected<StringRef> readBlobInRecord(BitstreamCursor &Stream,
+                                            unsigned Block, unsigned RecordID) {
+  if (Stream.EnterSubBlock(Block))
+    return error("Invalid record");
+
+  StringRef Strtab;
+  while (1) {
+    BitstreamEntry Entry = Stream.advance();
+    switch (Entry.Kind) {
+    case BitstreamEntry::EndBlock:
+      return Strtab;
+
+    case BitstreamEntry::Error:
+      return error("Malformed block");
+
+    case BitstreamEntry::SubBlock:
+      if (Stream.SkipBlock())
+        return error("Malformed block");
+      break;
+
+    case BitstreamEntry::Record:
+      StringRef Blob;
+      SmallVector<uint64_t, 1> Record;
+      if (Stream.readRecord(Entry.ID, Record, &Blob) == RecordID)
+        Strtab = Blob;
+      break;
+    }
+  }
+}
+
 //===----------------------------------------------------------------------===//
 // External interface
 //===----------------------------------------------------------------------===//
 
 Expected<std::vector<BitcodeModule>>
 llvm::getBitcodeModuleList(MemoryBufferRef Buffer) {
+  auto FOrErr = getBitcodeFileContents(Buffer);
+  if (!FOrErr)
+    return FOrErr.takeError();
+  return std::move(FOrErr->Mods);
+}
+
+Expected<BitcodeFileContents>
+llvm::getBitcodeFileContents(MemoryBufferRef Buffer) {
   Expected<BitstreamCursor> StreamOrErr = initStream(Buffer);
   if (!StreamOrErr)
     return StreamOrErr.takeError();
   BitstreamCursor &Stream = *StreamOrErr;
 
-  std::vector<BitcodeModule> Modules;
+  BitcodeFileContents F;
   while (true) {
     uint64_t BCBegin = Stream.getCurrentByteNo();
 
@@ -5167,7 +5463,7 @@ llvm::getBitcodeModuleList(MemoryBufferRef Buffer) {
     // of the bitcode stream (e.g. Apple's ar tool). If we are close enough to
     // the end that there cannot possibly be another module, stop looking.
     if (BCBegin + 8 >= Stream.getBitcodeBytes().size())
-      return Modules;
+      return F;
 
     BitstreamEntry Entry = Stream.advance();
     switch (Entry.Kind) {
@@ -5193,10 +5489,49 @@ llvm::getBitcodeModuleList(MemoryBufferRef Buffer) {
         if (Stream.SkipBlock())
           return error("Malformed block");
 
-        Modules.push_back({Stream.getBitcodeBytes().slice(
-                               BCBegin, Stream.getCurrentByteNo() - BCBegin),
-                           Buffer.getBufferIdentifier(), IdentificationBit,
-                           ModuleBit});
+        F.Mods.push_back({Stream.getBitcodeBytes().slice(
+                              BCBegin, Stream.getCurrentByteNo() - BCBegin),
+                          Buffer.getBufferIdentifier(), IdentificationBit,
+                          ModuleBit});
+        continue;
+      }
+
+      if (Entry.ID == bitc::STRTAB_BLOCK_ID) {
+        Expected<StringRef> Strtab =
+            readBlobInRecord(Stream, bitc::STRTAB_BLOCK_ID, bitc::STRTAB_BLOB);
+        if (!Strtab)
+          return Strtab.takeError();
+        // This string table is used by every preceding bitcode module that does
+        // not have its own string table. A bitcode file may have multiple
+        // string tables if it was created by binary concatenation, for example
+        // with "llvm-cat -b".
+        for (auto I = F.Mods.rbegin(), E = F.Mods.rend(); I != E; ++I) {
+          if (!I->Strtab.empty())
+            break;
+          I->Strtab = *Strtab;
+        }
+        // Similarly, the string table is used by every preceding symbol table;
+        // normally there will be just one unless the bitcode file was created
+        // by binary concatenation.
+        if (!F.Symtab.empty() && F.StrtabForSymtab.empty())
+          F.StrtabForSymtab = *Strtab;
+        continue;
+      }
+
+      if (Entry.ID == bitc::SYMTAB_BLOCK_ID) {
+        Expected<StringRef> SymtabOrErr =
+            readBlobInRecord(Stream, bitc::SYMTAB_BLOCK_ID, bitc::SYMTAB_BLOB);
+        if (!SymtabOrErr)
+          return SymtabOrErr.takeError();
+
+        // We can expect the bitcode file to have multiple symbol tables if it
+        // was created by binary concatenation. In that case we silently
+        // ignore any subsequent symbol tables, which is fine because this is a
+        // low level function. The client is expected to notice that the number
+        // of modules in the symbol table does not match the number of modules
+        // in the input file and regenerate the symbol table.
+        if (F.Symtab.empty())
+          F.Symtab = *SymtabOrErr;
         continue;
       }
 
@@ -5236,8 +5571,8 @@ BitcodeModule::getModuleImpl(LLVMContext &Context, bool MaterializeAll,
   }
 
   Stream.JumpToBit(ModuleBit);
-  auto *R =
-      new BitcodeReader(std::move(Stream), ProducerIdentification, Context);
+  auto *R = new BitcodeReader(std::move(Stream), Strtab, ProducerIdentification,
+                              Context);
 
   std::unique_ptr<Module> M =
       llvm::make_unique<Module>(ModuleIdentifier, Context);
@@ -5266,22 +5601,37 @@ BitcodeModule::getLazyModule(LLVMContext &Context, bool ShouldLazyLoadMetadata,
   return getModuleImpl(Context, false, ShouldLazyLoadMetadata, IsImporting);
 }
 
+// Parse the specified bitcode buffer and merge the index into CombinedIndex.
+// We don't use ModuleIdentifier here because the client may need to control the
+// module path used in the combined summary (e.g. when reading summaries for
+// regular LTO modules).
+Error BitcodeModule::readSummary(ModuleSummaryIndex &CombinedIndex,
+                                 StringRef ModulePath, uint64_t ModuleId) {
+  BitstreamCursor Stream(Buffer);
+  Stream.JumpToBit(ModuleBit);
+
+  ModuleSummaryIndexBitcodeReader R(std::move(Stream), Strtab, CombinedIndex,
+                                    ModulePath, ModuleId);
+  return R.parseModule();
+}
+
 // Parse the specified bitcode buffer, returning the function info index.
 Expected<std::unique_ptr<ModuleSummaryIndex>> BitcodeModule::getSummary() {
   BitstreamCursor Stream(Buffer);
   Stream.JumpToBit(ModuleBit);
 
   auto Index = llvm::make_unique<ModuleSummaryIndex>();
-  ModuleSummaryIndexBitcodeReader R(std::move(Stream), *Index);
+  ModuleSummaryIndexBitcodeReader R(std::move(Stream), Strtab, *Index,
+                                    ModuleIdentifier, 0);
 
-  if (Error Err = R.parseModule(ModuleIdentifier))
+  if (Error Err = R.parseModule())
     return std::move(Err);
 
   return std::move(Index);
 }
 
 // Check if the given bitcode buffer contains a global value summary block.
-Expected<bool> BitcodeModule::hasSummary() {
+Expected<BitcodeLTOInfo> BitcodeModule::getLTOInfo() {
   BitstreamCursor Stream(Buffer);
   Stream.JumpToBit(ModuleBit);
 
@@ -5295,11 +5645,14 @@ Expected<bool> BitcodeModule::hasSummary() {
     case BitstreamEntry::Error:
       return error("Malformed block");
     case BitstreamEntry::EndBlock:
-      return false;
+      return BitcodeLTOInfo{/*IsThinLTO=*/false, /*HasSummary=*/false};
 
     case BitstreamEntry::SubBlock:
       if (Entry.ID == bitc::GLOBALVAL_SUMMARY_BLOCK_ID)
-        return true;
+        return BitcodeLTOInfo{/*IsThinLTO=*/true, /*HasSummary=*/true};
+
+      if (Entry.ID == bitc::FULL_LTO_GLOBALVAL_SUMMARY_BLOCK_ID)
+        return BitcodeLTOInfo{/*IsThinLTO=*/false, /*HasSummary=*/true};
 
       // Ignore other sub-blocks.
       if (Stream.SkipBlock())
@@ -5384,6 +5737,16 @@ Expected<std::string> llvm::getBitcodeProducerString(MemoryBufferRef Buffer) {
   return readIdentificationCode(*StreamOrErr);
 }
 
+Error llvm::readModuleSummaryIndex(MemoryBufferRef Buffer,
+                                   ModuleSummaryIndex &CombinedIndex,
+                                   uint64_t ModuleId) {
+  Expected<BitcodeModule> BM = getSingleModule(Buffer);
+  if (!BM)
+    return BM.takeError();
+
+  return BM->readSummary(CombinedIndex, BM->getModuleIdentifier(), ModuleId);
+}
+
 Expected<std::unique_ptr<ModuleSummaryIndex>>
 llvm::getModuleSummaryIndex(MemoryBufferRef Buffer) {
   Expected<BitcodeModule> BM = getSingleModule(Buffer);
@@ -5393,10 +5756,22 @@ llvm::getModuleSummaryIndex(MemoryBufferRef Buffer) {
   return BM->getSummary();
 }
 
-Expected<bool> llvm::hasGlobalValueSummary(MemoryBufferRef Buffer) {
+Expected<BitcodeLTOInfo> llvm::getBitcodeLTOInfo(MemoryBufferRef Buffer) {
   Expected<BitcodeModule> BM = getSingleModule(Buffer);
   if (!BM)
     return BM.takeError();
 
-  return BM->hasSummary();
+  return BM->getLTOInfo();
+}
+
+Expected<std::unique_ptr<ModuleSummaryIndex>>
+llvm::getModuleSummaryIndexForFile(StringRef Path,
+                                   bool IgnoreEmptyThinLTOIndexFile) {
+  ErrorOr<std::unique_ptr<MemoryBuffer>> FileOrErr =
+      MemoryBuffer::getFileOrSTDIN(Path);
+  if (!FileOrErr)
+    return errorCodeToError(FileOrErr.getError());
+  if (IgnoreEmptyThinLTOIndexFile && !(*FileOrErr)->getBufferSize())
+    return nullptr;
+  return getModuleSummaryIndex(**FileOrErr);
 }
diff --git a/contrib/llvm/lib/Bitcode/Reader/MetadataLoader.cpp b/contrib/llvm/lib/Bitcode/Reader/MetadataLoader.cpp
index b89f5be..10fbcde 100644
--- a/contrib/llvm/lib/Bitcode/Reader/MetadataLoader.cpp
+++ b/contrib/llvm/lib/Bitcode/Reader/MetadataLoader.cpp
@@ -53,6 +53,7 @@
 #include "llvm/IR/InstrTypes.h"
 #include "llvm/IR/Instruction.h"
 #include "llvm/IR/Instructions.h"
+#include "llvm/IR/IntrinsicInst.h"
 #include "llvm/IR/Intrinsics.h"
 #include "llvm/IR/LLVMContext.h"
 #include "llvm/IR/Module.h"
@@ -358,6 +359,9 @@ class PlaceholderQueue {
   std::deque<DistinctMDOperandPlaceholder> PHs;
 
 public:
+  ~PlaceholderQueue() {
+    assert(empty() && "PlaceholderQueue hasn't been flushed before being destroyed");
+  }
   bool empty() { return PHs.empty(); }
   DistinctMDOperandPlaceholder &getPlaceholderOp(unsigned ID);
   void flush(BitcodeReaderMetadataList &MetadataList);
@@ -403,6 +407,11 @@ void PlaceholderQueue::flush(BitcodeReaderMetadataList &MetadataList) {
 
 } // anonynous namespace
 
+static Error error(const Twine &Message) {
+  return make_error<StringError>(
+      Message, make_error_code(BitcodeError::CorruptedBitcode));
+}
+
 class MetadataLoader::MetadataLoaderImpl {
   BitcodeReaderMetadataList MetadataList;
   BitcodeReaderValueList &ValueList;
@@ -449,6 +458,7 @@ class MetadataLoader::MetadataLoaderImpl {
   bool StripTBAA = false;
   bool HasSeenOldLoopTags = false;
   bool NeedUpgradeToDIGlobalVariableExpression = false;
+  bool NeedDeclareExpressionUpgrade = false;
 
   /// True if metadata is being parsed for a module being ThinLTO imported.
   bool IsImporting = false;
@@ -457,7 +467,7 @@ class MetadataLoader::MetadataLoaderImpl {
                          PlaceholderQueue &Placeholders, StringRef Blob,
                          unsigned &NextMetadataNo);
   Error parseMetadataStrings(ArrayRef<uint64_t> Record, StringRef Blob,
-                             std::function<void(StringRef)> CallBack);
+                             function_ref<void(StringRef)> CallBack);
   Error parseGlobalObjectAttachment(GlobalObject &GO,
                                     ArrayRef<uint64_t> Record);
   Error parseMetadataKindRecord(SmallVectorImpl<uint64_t> &Record);
@@ -469,8 +479,8 @@ class MetadataLoader::MetadataLoaderImpl {
     for (auto CU_SP : CUSubprograms)
       if (auto *SPs = dyn_cast_or_null<MDTuple>(CU_SP.second))
         for (auto &Op : SPs->operands())
-          if (auto *SP = dyn_cast_or_null<MDNode>(Op))
-            SP->replaceOperandWith(7, CU_SP.first);
+          if (auto *SP = dyn_cast_or_null<DISubprogram>(Op))
+            SP->replaceUnit(CU_SP.first);
     CUSubprograms.clear();
   }
 
@@ -495,7 +505,7 @@ class MetadataLoader::MetadataLoaderImpl {
 
     // Upgrade variables attached to globals.
     for (auto &GV : TheModule.globals()) {
-      SmallVector<MDNode *, 1> MDs, NewMDs;
+      SmallVector<MDNode *, 1> MDs;
       GV.getMetadata(LLVMContext::MD_dbg, MDs);
       GV.eraseMetadata(LLVMContext::MD_dbg);
       for (auto *MD : MDs)
@@ -508,6 +518,108 @@ class MetadataLoader::MetadataLoaderImpl {
     }
   }
 
+  /// Remove a leading DW_OP_deref from DIExpressions in a dbg.declare that
+  /// describes a function argument.
+  void upgradeDeclareExpressions(Function &F) {
+    if (!NeedDeclareExpressionUpgrade)
+      return;
+
+    for (auto &BB : F)
+      for (auto &I : BB)
+        if (auto *DDI = dyn_cast<DbgDeclareInst>(&I))
+          if (auto *DIExpr = DDI->getExpression())
+            if (DIExpr->startsWithDeref() &&
+                dyn_cast_or_null<Argument>(DDI->getAddress())) {
+              SmallVector<uint64_t, 8> Ops;
+              Ops.append(std::next(DIExpr->elements_begin()),
+                         DIExpr->elements_end());
+              auto *E = DIExpression::get(Context, Ops);
+              DDI->setOperand(2, MetadataAsValue::get(Context, E));
+            }
+  }
+
+  /// Upgrade the expression from previous versions.
+  Error upgradeDIExpression(uint64_t FromVersion,
+                            MutableArrayRef<uint64_t> &Expr,
+                            SmallVectorImpl<uint64_t> &Buffer) {
+    auto N = Expr.size();
+    switch (FromVersion) {
+    default:
+      return error("Invalid record");
+    case 0:
+      if (N >= 3 && Expr[N - 3] == dwarf::DW_OP_bit_piece)
+        Expr[N - 3] = dwarf::DW_OP_LLVM_fragment;
+      LLVM_FALLTHROUGH;
+    case 1:
+      // Move DW_OP_deref to the end.
+      if (N && Expr[0] == dwarf::DW_OP_deref) {
+        auto End = Expr.end();
+        if (Expr.size() >= 3 &&
+            *std::prev(End, 3) == dwarf::DW_OP_LLVM_fragment)
+          End = std::prev(End, 3);
+        std::move(std::next(Expr.begin()), End, Expr.begin());
+        *std::prev(End) = dwarf::DW_OP_deref;
+      }
+      NeedDeclareExpressionUpgrade = true;
+      LLVM_FALLTHROUGH;
+    case 2: {
+      // Change DW_OP_plus to DW_OP_plus_uconst.
+      // Change DW_OP_minus to DW_OP_uconst, DW_OP_minus
+      auto SubExpr = ArrayRef<uint64_t>(Expr);
+      while (!SubExpr.empty()) {
+        // Skip past other operators with their operands
+        // for this version of the IR, obtained from
+        // from historic DIExpression::ExprOperand::getSize().
+        size_t HistoricSize;
+        switch (SubExpr.front()) {
+        default:
+          HistoricSize = 1;
+          break;
+        case dwarf::DW_OP_constu:
+        case dwarf::DW_OP_minus:
+        case dwarf::DW_OP_plus:
+          HistoricSize = 2;
+          break;
+        case dwarf::DW_OP_LLVM_fragment:
+          HistoricSize = 3;
+          break;
+        }
+
+        // If the expression is malformed, make sure we don't
+        // copy more elements than we should.
+        HistoricSize = std::min(SubExpr.size(), HistoricSize);
+        ArrayRef<uint64_t> Args = SubExpr.slice(1, HistoricSize-1);
+
+        switch (SubExpr.front()) {
+        case dwarf::DW_OP_plus:
+          Buffer.push_back(dwarf::DW_OP_plus_uconst);
+          Buffer.append(Args.begin(), Args.end());
+          break;
+        case dwarf::DW_OP_minus:
+          Buffer.push_back(dwarf::DW_OP_constu);
+          Buffer.append(Args.begin(), Args.end());
+          Buffer.push_back(dwarf::DW_OP_minus);
+          break;
+        default:
+          Buffer.push_back(*SubExpr.begin());
+          Buffer.append(Args.begin(), Args.end());
+          break;
+        }
+
+        // Continue with remaining elements.
+        SubExpr = SubExpr.slice(HistoricSize);
+      }
+      Expr = MutableArrayRef<uint64_t>(Buffer);
+      LLVM_FALLTHROUGH;
+    }
+    case 3:
+      // Up-to-date!
+      break;
+    }
+
+    return Error::success();
+  }
+
   void upgradeDebugInfo() {
     upgradeCUSubprograms();
     upgradeCUVariables();
@@ -520,7 +632,7 @@ public:
                      bool IsImporting)
       : MetadataList(TheModule.getContext()), ValueList(ValueList),
         Stream(Stream), Context(TheModule.getContext()), TheModule(TheModule),
-        getTypeByID(getTypeByID), IsImporting(IsImporting) {}
+        getTypeByID(std::move(getTypeByID)), IsImporting(IsImporting) {}
 
   Error parseMetadata(bool ModuleLevel);
 
@@ -562,13 +674,9 @@ public:
 
   unsigned size() const { return MetadataList.size(); }
   void shrinkTo(unsigned N) { MetadataList.shrinkTo(N); }
+  void upgradeDebugIntrinsics(Function &F) { upgradeDeclareExpressions(F); }
 };
 
-Error error(const Twine &Message) {
-  return make_error<StringError>(
-      Message, make_error_code(BitcodeError::CorruptedBitcode));
-}
-
 Expected<bool>
 MetadataLoader::MetadataLoaderImpl::lazyLoadModuleMetadataBlock() {
   IndexCursor = Stream;
@@ -1107,9 +1215,15 @@ Error MetadataLoader::MetadataLoaderImpl::parseOneMetadata(
     break;
   }
   case bitc::METADATA_DERIVED_TYPE: {
-    if (Record.size() != 12)
+    if (Record.size() < 12 || Record.size() > 13)
       return error("Invalid record");
 
+    // DWARF address space is encoded as N->getDWARFAddressSpace() + 1. 0 means
+    // that there is no DWARF address space associated with DIDerivedType.
+    Optional<unsigned> DWARFAddressSpace;
+    if (Record.size() > 12 && Record[12])
+      DWARFAddressSpace = Record[12] - 1;
+
     IsDistinct = Record[0];
     DINode::DIFlags Flags = static_cast<DINode::DIFlags>(Record[10]);
     MetadataList.assignValue(
@@ -1118,7 +1232,8 @@ Error MetadataLoader::MetadataLoaderImpl::parseOneMetadata(
                          getMDOrNull(Record[3]), Record[4],
                          getDITypeRefOrNull(Record[5]),
                          getDITypeRefOrNull(Record[6]), Record[7], Record[8],
-                         Record[9], Flags, getDITypeRefOrNull(Record[11]))),
+                         Record[9], DWARFAddressSpace, Flags,
+                         getDITypeRefOrNull(Record[11]))),
         NextMetadataNo);
     NextMetadataNo++;
     break;
@@ -1240,7 +1355,7 @@ Error MetadataLoader::MetadataLoaderImpl::parseOneMetadata(
     break;
   }
   case bitc::METADATA_COMPILE_UNIT: {
-    if (Record.size() < 14 || Record.size() > 17)
+    if (Record.size() < 14 || Record.size() > 18)
       return error("Invalid record");
 
     // Ignore Record[0], which indicates whether this compile unit is
@@ -1253,7 +1368,8 @@ Error MetadataLoader::MetadataLoaderImpl::parseOneMetadata(
         getMDOrNull(Record[12]), getMDOrNull(Record[13]),
         Record.size() <= 15 ? nullptr : getMDOrNull(Record[15]),
         Record.size() <= 14 ? 0 : Record[14],
-        Record.size() <= 16 ? true : Record[16]);
+        Record.size() <= 16 ? true : Record[16],
+        Record.size() <= 17 ? false : Record[17]);
 
     MetadataList.assignValue(CU, NextMetadataNo);
     NextMetadataNo++;
@@ -1264,7 +1380,7 @@ Error MetadataLoader::MetadataLoaderImpl::parseOneMetadata(
     break;
   }
   case bitc::METADATA_SUBPROGRAM: {
-    if (Record.size() < 18 || Record.size() > 20)
+    if (Record.size() < 18 || Record.size() > 21)
       return error("Invalid record");
 
     IsDistinct =
@@ -1280,29 +1396,31 @@ Error MetadataLoader::MetadataLoaderImpl::parseOneMetadata(
     unsigned Offset = Record.size() >= 19 ? 1 : 0;
     bool HasFn = Offset && !HasUnit;
     bool HasThisAdj = Record.size() >= 20;
+    bool HasThrownTypes = Record.size() >= 21;
     DISubprogram *SP = GET_OR_DISTINCT(
-        DISubprogram, (Context,
-                       getDITypeRefOrNull(Record[1]),          // scope
-                       getMDString(Record[2]),                 // name
-                       getMDString(Record[3]),                 // linkageName
-                       getMDOrNull(Record[4]),                 // file
-                       Record[5],                              // line
-                       getMDOrNull(Record[6]),                 // type
-                       Record[7],                              // isLocal
-                       Record[8],                              // isDefinition
-                       Record[9],                              // scopeLine
-                       getDITypeRefOrNull(Record[10]),         // containingType
-                       Record[11],                             // virtuality
-                       Record[12],                             // virtualIndex
-                       HasThisAdj ? Record[19] : 0,            // thisAdjustment
-                       static_cast<DINode::DIFlags>(Record[13] // flags
-                                                    ),
-                       Record[14],                       // isOptimized
-                       HasUnit ? CUorFn : nullptr,       // unit
-                       getMDOrNull(Record[15 + Offset]), // templateParams
-                       getMDOrNull(Record[16 + Offset]), // declaration
-                       getMDOrNull(Record[17 + Offset])  // variables
-                       ));
+        DISubprogram,
+        (Context,
+         getDITypeRefOrNull(Record[1]),                     // scope
+         getMDString(Record[2]),                            // name
+         getMDString(Record[3]),                            // linkageName
+         getMDOrNull(Record[4]),                            // file
+         Record[5],                                         // line
+         getMDOrNull(Record[6]),                            // type
+         Record[7],                                         // isLocal
+         Record[8],                                         // isDefinition
+         Record[9],                                         // scopeLine
+         getDITypeRefOrNull(Record[10]),                    // containingType
+         Record[11],                                        // virtuality
+         Record[12],                                        // virtualIndex
+         HasThisAdj ? Record[19] : 0,                       // thisAdjustment
+         static_cast<DINode::DIFlags>(Record[13]),          // flags
+         Record[14],                                        // isOptimized
+         HasUnit ? CUorFn : nullptr,                        // unit
+         getMDOrNull(Record[15 + Offset]),                  // templateParams
+         getMDOrNull(Record[16 + Offset]),                  // declaration
+         getMDOrNull(Record[17 + Offset]),                  // variables
+         HasThrownTypes ? getMDOrNull(Record[20]) : nullptr // thrownTypes
+         ));
     MetadataList.assignValue(SP, NextMetadataNo);
     NextMetadataNo++;
 
@@ -1347,16 +1465,20 @@ Error MetadataLoader::MetadataLoaderImpl::parseOneMetadata(
     break;
   }
   case bitc::METADATA_NAMESPACE: {
-    if (Record.size() != 5)
+    // Newer versions of DINamespace dropped file and line.
+    MDString *Name;
+    if (Record.size() == 3)
+      Name = getMDString(Record[2]);
+    else if (Record.size() == 5)
+      Name = getMDString(Record[3]);
+    else
       return error("Invalid record");
 
     IsDistinct = Record[0] & 1;
     bool ExportSymbols = Record[0] & 2;
     MetadataList.assignValue(
         GET_OR_DISTINCT(DINamespace,
-                        (Context, getMDOrNull(Record[1]),
-                         getMDOrNull(Record[2]), getMDString(Record[3]),
-                         Record[4], ExportSymbols)),
+                        (Context, getMDOrNull(Record[1]), Name, ExportSymbols)),
         NextMetadataNo);
     NextMetadataNo++;
     break;
@@ -1433,6 +1555,7 @@ Error MetadataLoader::MetadataLoaderImpl::parseOneMetadata(
     } else if (Version == 0) {
       // Upgrade old metadata, which stored a global variable reference or a
       // ConstantInt here.
+      NeedUpgradeToDIGlobalVariableExpression = true;
       Metadata *Expr = getMDOrNull(Record[9]);
       uint32_t AlignInBits = 0;
       if (Record.size() > 11) {
@@ -1463,8 +1586,6 @@ Error MetadataLoader::MetadataLoaderImpl::parseOneMetadata(
       DIGlobalVariableExpression *DGVE = nullptr;
       if (Attach || Expr)
         DGVE = DIGlobalVariableExpression::getDistinct(Context, DGV, Expr);
-      else
-        NeedUpgradeToDIGlobalVariableExpression = true;
       if (Attach)
         Attach->addDebugInfo(DGVE);
 
@@ -1485,7 +1606,7 @@ Error MetadataLoader::MetadataLoaderImpl::parseOneMetadata(
     bool HasAlignment = Record[0] & 2;
     // 2nd field used to be an artificial tag, either DW_TAG_auto_variable or
     // DW_TAG_arg_variable, if we have alignment flag encoded it means, that
-    // this is newer version of record which doesn't have artifical tag.
+    // this is newer version of record which doesn't have artificial tag.
     bool HasTag = !HasAlignment && Record.size() > 8;
     DINode::DIFlags Flags = static_cast<DINode::DIFlags>(Record[7 + HasTag]);
     uint32_t AlignInBits = 0;
@@ -1510,16 +1631,15 @@ Error MetadataLoader::MetadataLoaderImpl::parseOneMetadata(
       return error("Invalid record");
 
     IsDistinct = Record[0] & 1;
-    bool HasOpFragment = Record[0] & 2;
+    uint64_t Version = Record[0] >> 1;
     auto Elts = MutableArrayRef<uint64_t>(Record).slice(1);
-    if (!HasOpFragment)
-      if (unsigned N = Elts.size())
-        if (N >= 3 && Elts[N - 3] == dwarf::DW_OP_bit_piece)
-          Elts[N - 3] = dwarf::DW_OP_LLVM_fragment;
+
+    SmallVector<uint64_t, 6> Buffer;
+    if (Error Err = upgradeDIExpression(Version, Elts, Buffer))
+      return Err;
 
     MetadataList.assignValue(
-        GET_OR_DISTINCT(DIExpression, (Context, makeArrayRef(Record).slice(1))),
-        NextMetadataNo);
+        GET_OR_DISTINCT(DIExpression, (Context, Elts)), NextMetadataNo);
     NextMetadataNo++;
     break;
   }
@@ -1551,15 +1671,17 @@ Error MetadataLoader::MetadataLoaderImpl::parseOneMetadata(
     break;
   }
   case bitc::METADATA_IMPORTED_ENTITY: {
-    if (Record.size() != 6)
+    if (Record.size() != 6 && Record.size() != 7)
       return error("Invalid record");
 
     IsDistinct = Record[0];
+    bool HasFile = (Record.size() == 7);
     MetadataList.assignValue(
         GET_OR_DISTINCT(DIImportedEntity,
                         (Context, Record[1], getMDOrNull(Record[2]),
-                         getDITypeRefOrNull(Record[3]), Record[4],
-                         getMDString(Record[5]))),
+                         getDITypeRefOrNull(Record[3]),
+                         HasFile ? getMDOrNull(Record[6]) : nullptr,
+                         HasFile ? Record[4] : 0, getMDString(Record[5]))),
         NextMetadataNo);
     NextMetadataNo++;
     break;
@@ -1611,7 +1733,7 @@ Error MetadataLoader::MetadataLoaderImpl::parseOneMetadata(
 
 Error MetadataLoader::MetadataLoaderImpl::parseMetadataStrings(
     ArrayRef<uint64_t> Record, StringRef Blob,
-    std::function<void(StringRef)> CallBack) {
+    function_ref<void(StringRef)> CallBack) {
   // All the MDStrings in the block are emitted together in a single
   // record.  The strings are concatenated and stored in a blob along with
   // their sizes.
@@ -1808,8 +1930,8 @@ MetadataLoader::MetadataLoader(BitstreamCursor &Stream, Module &TheModule,
                                BitcodeReaderValueList &ValueList,
                                bool IsImporting,
                                std::function<Type *(unsigned)> getTypeByID)
-    : Pimpl(llvm::make_unique<MetadataLoaderImpl>(Stream, TheModule, ValueList,
-                                                  getTypeByID, IsImporting)) {}
+    : Pimpl(llvm::make_unique<MetadataLoaderImpl>(
+          Stream, TheModule, ValueList, std::move(getTypeByID), IsImporting)) {}
 
 Error MetadataLoader::parseMetadata(bool ModuleLevel) {
   return Pimpl->parseMetadata(ModuleLevel);
@@ -1848,3 +1970,7 @@ bool MetadataLoader::isStrippingTBAA() { return Pimpl->isStrippingTBAA(); }
 
 unsigned MetadataLoader::size() const { return Pimpl->size(); }
 void MetadataLoader::shrinkTo(unsigned N) { return Pimpl->shrinkTo(N); }
+
+void MetadataLoader::upgradeDebugIntrinsics(Function &F) {
+  return Pimpl->upgradeDebugIntrinsics(F);
+}
diff --git a/contrib/llvm/lib/Bitcode/Reader/MetadataLoader.h b/contrib/llvm/lib/Bitcode/Reader/MetadataLoader.h
index 442dfc9..f23dcc0 100644
--- a/contrib/llvm/lib/Bitcode/Reader/MetadataLoader.h
+++ b/contrib/llvm/lib/Bitcode/Reader/MetadataLoader.h
@@ -79,6 +79,9 @@ public:
 
   unsigned size() const;
   void shrinkTo(unsigned N);
+
+  /// Perform bitcode upgrades on llvm.dbg.* calls.
+  void upgradeDebugIntrinsics(Function &F);
 };
 }
 
diff --git a/contrib/llvm/lib/Bitcode/Reader/ValueList.cpp b/contrib/llvm/lib/Bitcode/Reader/ValueList.cpp
index 7152a51..f2a3439 100644
--- a/contrib/llvm/lib/Bitcode/Reader/ValueList.cpp
+++ b/contrib/llvm/lib/Bitcode/Reader/ValueList.cpp
@@ -58,7 +58,7 @@ void BitcodeReaderValueList::assignValue(Value *V, unsigned Idx) {
   if (Idx >= size())
     resize(Idx + 1);
 
-  WeakVH &OldV = ValuePtrs[Idx];
+  WeakTrackingVH &OldV = ValuePtrs[Idx];
   if (!OldV) {
     OldV = V;
     return;
@@ -73,7 +73,7 @@ void BitcodeReaderValueList::assignValue(Value *V, unsigned Idx) {
     // If there was a forward reference to this value, replace it.
     Value *PrevVal = OldV;
     OldV->replaceAllUsesWith(V);
-    delete PrevVal;
+    PrevVal->deleteValue();
   }
 }
 
@@ -194,6 +194,6 @@ void BitcodeReaderValueList::resolveConstantForwardRefs() {
 
     // Update all ValueHandles, they should be the only users at this point.
     Placeholder->replaceAllUsesWith(RealVal);
-    delete Placeholder;
+    Placeholder->deleteValue();
   }
 }
diff --git a/contrib/llvm/lib/Bitcode/Reader/ValueList.h b/contrib/llvm/lib/Bitcode/Reader/ValueList.h
index 3119d77..72775a3 100644
--- a/contrib/llvm/lib/Bitcode/Reader/ValueList.h
+++ b/contrib/llvm/lib/Bitcode/Reader/ValueList.h
@@ -20,7 +20,7 @@ namespace llvm {
 class Constant;
 
 class BitcodeReaderValueList {
-  std::vector<WeakVH> ValuePtrs;
+  std::vector<WeakTrackingVH> ValuePtrs;
 
   /// As we resolve forward-referenced constants, we add information about them
   /// to this vector.  This allows us to resolve them in bulk instead of
diff --git a/contrib/llvm/lib/Bitcode/Writer/BitcodeWriter.cpp b/contrib/llvm/lib/Bitcode/Writer/BitcodeWriter.cpp
index ebb2022..dcffde1 100644
--- a/contrib/llvm/lib/Bitcode/Writer/BitcodeWriter.cpp
+++ b/contrib/llvm/lib/Bitcode/Writer/BitcodeWriter.cpp
@@ -28,10 +28,13 @@
 #include "llvm/IR/Operator.h"
 #include "llvm/IR/UseListOrder.h"
 #include "llvm/IR/ValueSymbolTable.h"
+#include "llvm/MC/StringTableBuilder.h"
+#include "llvm/Object/IRSymtab.h"
 #include "llvm/Support/ErrorHandling.h"
 #include "llvm/Support/MathExtras.h"
 #include "llvm/Support/Program.h"
 #include "llvm/Support/SHA1.h"
+#include "llvm/Support/TargetRegistry.h"
 #include "llvm/Support/raw_ostream.h"
 #include <cctype>
 #include <map>
@@ -76,21 +79,24 @@ protected:
   /// The stream created and owned by the client.
   BitstreamWriter &Stream;
 
-  /// Saves the offset of the VSTOffset record that must eventually be
-  /// backpatched with the offset of the actual VST.
-  uint64_t VSTOffsetPlaceholder = 0;
+  StringTableBuilder &StrtabBuilder;
 
 public:
   /// Constructs a BitcodeWriterBase object that writes to the provided
   /// \p Stream.
-  BitcodeWriterBase(BitstreamWriter &Stream) : Stream(Stream) {}
+  BitcodeWriterBase(BitstreamWriter &Stream, StringTableBuilder &StrtabBuilder)
+      : Stream(Stream), StrtabBuilder(StrtabBuilder) {}
 
 protected:
-  bool hasVSTOffsetPlaceholder() { return VSTOffsetPlaceholder != 0; }
-  void writeValueSymbolTableForwardDecl();
   void writeBitcodeHeader();
+  void writeModuleVersion();
 };
 
+void BitcodeWriterBase::writeModuleVersion() {
+  // VERSION: [version#]
+  Stream.EmitRecord(bitc::MODULE_CODE_VERSION, ArrayRef<uint64_t>{2});
+}
+
 /// Class to manage the bitcode writing for a module.
 class ModuleBitcodeWriter : public BitcodeWriterBase {
   /// Pointer to the buffer allocated by caller for bitcode writing.
@@ -108,6 +114,16 @@ class ModuleBitcodeWriter : public BitcodeWriterBase {
   /// True if a module hash record should be written.
   bool GenerateHash;
 
+  SHA1 Hasher;
+
+  /// If non-null, when GenerateHash is true, the resulting hash is written
+  /// into ModHash. When GenerateHash is false, that specified value
+  /// is used as the hash instead of computing from the generated bitcode.
+  /// Can be used to produce the same module hash for a minimized bitcode
+  /// used just for the thin link as in the regular full bitcode that will
+  /// be used in the backend.
+  ModuleHash *ModHash;
+
   /// The start bit of the identification block.
   uint64_t BitcodeStartBit;
 
@@ -119,15 +135,22 @@ class ModuleBitcodeWriter : public BitcodeWriterBase {
   /// Tracks the last value id recorded in the GUIDToValueMap.
   unsigned GlobalValueId;
 
+  /// Saves the offset of the VSTOffset record that must eventually be
+  /// backpatched with the offset of the actual VST.
+  uint64_t VSTOffsetPlaceholder = 0;
+
 public:
   /// Constructs a ModuleBitcodeWriter object for the given Module,
   /// writing to the provided \p Buffer.
   ModuleBitcodeWriter(const Module *M, SmallVectorImpl<char> &Buffer,
+                      StringTableBuilder &StrtabBuilder,
                       BitstreamWriter &Stream, bool ShouldPreserveUseListOrder,
-                      const ModuleSummaryIndex *Index, bool GenerateHash)
-      : BitcodeWriterBase(Stream), Buffer(Buffer), M(*M),
+                      const ModuleSummaryIndex *Index, bool GenerateHash,
+                      ModuleHash *ModHash = nullptr)
+      : BitcodeWriterBase(Stream, StrtabBuilder), Buffer(Buffer), M(*M),
         VE(*M, ShouldPreserveUseListOrder), Index(Index),
-        GenerateHash(GenerateHash), BitcodeStartBit(Stream.GetCurrentBitNo()) {
+        GenerateHash(GenerateHash), ModHash(ModHash),
+        BitcodeStartBit(Stream.GetCurrentBitNo()) {
     // Assign ValueIds to any callee values in the index that came from
     // indirect call profiles and were recorded as a GUID not a Value*
     // (which would have been assigned an ID by the ValueEnumerator).
@@ -138,14 +161,14 @@ public:
       return;
     for (const auto &GUIDSummaryLists : *Index)
       // Examine all summaries for this GUID.
-      for (auto &Summary : GUIDSummaryLists.second)
+      for (auto &Summary : GUIDSummaryLists.second.SummaryList)
         if (auto FS = dyn_cast<FunctionSummary>(Summary.get()))
           // For each call in the function summary, see if the call
           // is to a GUID (which means it is for an indirect call,
           // otherwise we would have a Value for it). If so, synthesize
           // a value id.
           for (auto &CallEdge : FS->calls())
-            if (CallEdge.first.isGUID())
+            if (!CallEdge.first.getValue())
               assignValueId(CallEdge.first.getGUID());
   }
 
@@ -155,10 +178,13 @@ public:
 private:
   uint64_t bitcodeStartBit() { return BitcodeStartBit; }
 
+  size_t addToStrtab(StringRef Str);
+
   void writeAttributeGroupTable();
   void writeAttributeTable();
   void writeTypeTable();
   void writeComdats();
+  void writeValueSymbolTableForwardDecl();
   void writeModuleInfo();
   void writeValueAsMetadata(const ValueAsMetadata *MD,
                             SmallVectorImpl<uint64_t> &Record);
@@ -240,6 +266,7 @@ private:
                                     const GlobalObject &GO);
   void writeModuleMetadataKinds();
   void writeOperandBundleTags();
+  void writeSyncScopeNames();
   void writeConstants(unsigned FirstVal, unsigned LastVal, bool isGlobal);
   void writeModuleConstants();
   bool pushValueAndType(const Value *V, unsigned InstID,
@@ -251,9 +278,9 @@ private:
                        SmallVectorImpl<uint64_t> &Vals);
   void writeInstruction(const Instruction &I, unsigned InstID,
                         SmallVectorImpl<unsigned> &Vals);
-  void writeValueSymbolTable(
-      const ValueSymbolTable &VST, bool IsModuleLevel = false,
-      DenseMap<const Function *, uint64_t> *FunctionToBitcodeIndex = nullptr);
+  void writeFunctionLevelValueSymbolTable(const ValueSymbolTable &VST);
+  void writeGlobalValueSymbolTable(
+      DenseMap<const Function *, uint64_t> &FunctionToBitcodeIndex);
   void writeUseList(UseListOrder &&Order);
   void writeUseListBlock(const Function *F);
   void
@@ -285,11 +312,15 @@ private:
   }
   // Helper to get the valueId for the type of value recorded in VI.
   unsigned getValueId(ValueInfo VI) {
-    if (VI.isGUID())
+    if (!VI.getValue())
       return getValueId(VI.getGUID());
     return VE.getValueID(VI.getValue());
   }
   std::map<GlobalValue::GUID, unsigned> &valueIds() { return GUIDToValueIdMap; }
+
+  unsigned getEncodedSyncScopeID(SyncScope::ID SSID) {
+    return unsigned(SSID);
+  }
 };
 
 /// Class to manage the bitcode writing for a combined index.
@@ -312,186 +343,75 @@ public:
   /// Constructs a IndexBitcodeWriter object for the given combined index,
   /// writing to the provided \p Buffer. When writing a subset of the index
   /// for a distributed backend, provide a \p ModuleToSummariesForIndex map.
-  IndexBitcodeWriter(BitstreamWriter &Stream, const ModuleSummaryIndex &Index,
+  IndexBitcodeWriter(BitstreamWriter &Stream, StringTableBuilder &StrtabBuilder,
+                     const ModuleSummaryIndex &Index,
                      const std::map<std::string, GVSummaryMapTy>
                          *ModuleToSummariesForIndex = nullptr)
-      : BitcodeWriterBase(Stream), Index(Index),
+      : BitcodeWriterBase(Stream, StrtabBuilder), Index(Index),
         ModuleToSummariesForIndex(ModuleToSummariesForIndex) {
     // Assign unique value ids to all summaries to be written, for use
     // in writing out the call graph edges. Save the mapping from GUID
     // to the new global value id to use when writing those edges, which
     // are currently saved in the index in terms of GUID.
-    for (const auto &I : *this)
+    forEachSummary([&](GVInfo I) {
       GUIDToValueIdMap[I.first] = ++GlobalValueId;
+    });
   }
 
   /// The below iterator returns the GUID and associated summary.
   typedef std::pair<GlobalValue::GUID, GlobalValueSummary *> GVInfo;
 
-  /// Iterator over the value GUID and summaries to be written to bitcode,
-  /// hides the details of whether they are being pulled from the entire
-  /// index or just those in a provided ModuleToSummariesForIndex map.
-  class iterator
-      : public llvm::iterator_facade_base<iterator, std::forward_iterator_tag,
-                                          GVInfo> {
-    /// Enables access to parent class.
-    const IndexBitcodeWriter &Writer;
-
-    // Iterators used when writing only those summaries in a provided
-    // ModuleToSummariesForIndex map:
-
-    /// Points to the last element in outer ModuleToSummariesForIndex map.
-    std::map<std::string, GVSummaryMapTy>::const_iterator ModuleSummariesBack;
-    /// Iterator on outer ModuleToSummariesForIndex map.
-    std::map<std::string, GVSummaryMapTy>::const_iterator ModuleSummariesIter;
-    /// Iterator on an inner global variable summary map.
-    GVSummaryMapTy::const_iterator ModuleGVSummariesIter;
-
-    // Iterators used when writing all summaries in the index:
-
-    /// Points to the last element in the Index outer GlobalValueMap.
-    const_gvsummary_iterator IndexSummariesBack;
-    /// Iterator on outer GlobalValueMap.
-    const_gvsummary_iterator IndexSummariesIter;
-    /// Iterator on an inner GlobalValueSummaryList.
-    GlobalValueSummaryList::const_iterator IndexGVSummariesIter;
-
-  public:
-    /// Construct iterator from parent \p Writer and indicate if we are
-    /// constructing the end iterator.
-    iterator(const IndexBitcodeWriter &Writer, bool IsAtEnd) : Writer(Writer) {
-      // Set up the appropriate set of iterators given whether we are writing
-      // the full index or just a subset.
-      // Can't setup the Back or inner iterators if the corresponding map
-      // is empty. This will be handled specially in operator== as well.
-      if (Writer.ModuleToSummariesForIndex &&
-          !Writer.ModuleToSummariesForIndex->empty()) {
-        for (ModuleSummariesBack = Writer.ModuleToSummariesForIndex->begin();
-             std::next(ModuleSummariesBack) !=
-             Writer.ModuleToSummariesForIndex->end();
-             ModuleSummariesBack++)
-          ;
-        ModuleSummariesIter = !IsAtEnd
-                                  ? Writer.ModuleToSummariesForIndex->begin()
-                                  : ModuleSummariesBack;
-        ModuleGVSummariesIter = !IsAtEnd ? ModuleSummariesIter->second.begin()
-                                         : ModuleSummariesBack->second.end();
-      } else if (!Writer.ModuleToSummariesForIndex &&
-                 Writer.Index.begin() != Writer.Index.end()) {
-        for (IndexSummariesBack = Writer.Index.begin();
-             std::next(IndexSummariesBack) != Writer.Index.end();
-             IndexSummariesBack++)
-          ;
-        IndexSummariesIter =
-            !IsAtEnd ? Writer.Index.begin() : IndexSummariesBack;
-        IndexGVSummariesIter = !IsAtEnd ? IndexSummariesIter->second.begin()
-                                        : IndexSummariesBack->second.end();
-      }
+  /// Calls the callback for each value GUID and summary to be written to
+  /// bitcode. This hides the details of whether they are being pulled from the
+  /// entire index or just those in a provided ModuleToSummariesForIndex map.
+  template<typename Functor>
+  void forEachSummary(Functor Callback) {
+    if (ModuleToSummariesForIndex) {
+      for (auto &M : *ModuleToSummariesForIndex)
+        for (auto &Summary : M.second)
+          Callback(Summary);
+    } else {
+      for (auto &Summaries : Index)
+        for (auto &Summary : Summaries.second.SummaryList)
+          Callback({Summaries.first, Summary.get()});
     }
+  }
 
-    /// Increment the appropriate set of iterators.
-    iterator &operator++() {
-      // First the inner iterator is incremented, then if it is at the end
-      // and there are more outer iterations to go, the inner is reset to
-      // the start of the next inner list.
-      if (Writer.ModuleToSummariesForIndex) {
-        ++ModuleGVSummariesIter;
-        if (ModuleGVSummariesIter == ModuleSummariesIter->second.end() &&
-            ModuleSummariesIter != ModuleSummariesBack) {
-          ++ModuleSummariesIter;
-          ModuleGVSummariesIter = ModuleSummariesIter->second.begin();
-        }
-      } else {
-        ++IndexGVSummariesIter;
-        if (IndexGVSummariesIter == IndexSummariesIter->second.end() &&
-            IndexSummariesIter != IndexSummariesBack) {
-          ++IndexSummariesIter;
-          IndexGVSummariesIter = IndexSummariesIter->second.begin();
+  /// Calls the callback for each entry in the modulePaths StringMap that
+  /// should be written to the module path string table. This hides the details
+  /// of whether they are being pulled from the entire index or just those in a
+  /// provided ModuleToSummariesForIndex map.
+  template <typename Functor> void forEachModule(Functor Callback) {
+    if (ModuleToSummariesForIndex) {
+      for (const auto &M : *ModuleToSummariesForIndex) {
+        const auto &MPI = Index.modulePaths().find(M.first);
+        if (MPI == Index.modulePaths().end()) {
+          // This should only happen if the bitcode file was empty, in which
+          // case we shouldn't be importing (the ModuleToSummariesForIndex
+          // would only include the module we are writing and index for).
+          assert(ModuleToSummariesForIndex->size() == 1);
+          continue;
         }
+        Callback(*MPI);
       }
-      return *this;
-    }
-
-    /// Access the <GUID,GlobalValueSummary*> pair corresponding to the current
-    /// outer and inner iterator positions.
-    GVInfo operator*() {
-      if (Writer.ModuleToSummariesForIndex)
-        return std::make_pair(ModuleGVSummariesIter->first,
-                              ModuleGVSummariesIter->second);
-      return std::make_pair(IndexSummariesIter->first,
-                            IndexGVSummariesIter->get());
-    }
-
-    /// Checks if the iterators are equal, with special handling for empty
-    /// indexes.
-    bool operator==(const iterator &RHS) const {
-      if (Writer.ModuleToSummariesForIndex) {
-        // First ensure that both are writing the same subset.
-        if (Writer.ModuleToSummariesForIndex !=
-            RHS.Writer.ModuleToSummariesForIndex)
-          return false;
-        // Already determined above that maps are the same, so if one is
-        // empty, they both are.
-        if (Writer.ModuleToSummariesForIndex->empty())
-          return true;
-        // Ensure the ModuleGVSummariesIter are iterating over the same
-        // container before checking them below.
-        if (ModuleSummariesIter != RHS.ModuleSummariesIter)
-          return false;
-        return ModuleGVSummariesIter == RHS.ModuleGVSummariesIter;
-      }
-      // First ensure RHS also writing the full index, and that both are
-      // writing the same full index.
-      if (RHS.Writer.ModuleToSummariesForIndex ||
-          &Writer.Index != &RHS.Writer.Index)
-        return false;
-      // Already determined above that maps are the same, so if one is
-      // empty, they both are.
-      if (Writer.Index.begin() == Writer.Index.end())
-        return true;
-      // Ensure the IndexGVSummariesIter are iterating over the same
-      // container before checking them below.
-      if (IndexSummariesIter != RHS.IndexSummariesIter)
-        return false;
-      return IndexGVSummariesIter == RHS.IndexGVSummariesIter;
+    } else {
+      for (const auto &MPSE : Index.modulePaths())
+        Callback(MPSE);
     }
-  };
-
-  /// Obtain the start iterator over the summaries to be written.
-  iterator begin() { return iterator(*this, /*IsAtEnd=*/false); }
-  /// Obtain the end iterator over the summaries to be written.
-  iterator end() { return iterator(*this, /*IsAtEnd=*/true); }
+  }
 
   /// Main entry point for writing a combined index to bitcode.
   void write();
 
 private:
-  void writeIndex();
   void writeModStrings();
-  void writeCombinedValueSymbolTable();
   void writeCombinedGlobalValueSummary();
 
-  /// Indicates whether the provided \p ModulePath should be written into
-  /// the module string table, e.g. if full index written or if it is in
-  /// the provided subset.
-  bool doIncludeModule(StringRef ModulePath) {
-    return !ModuleToSummariesForIndex ||
-           ModuleToSummariesForIndex->count(ModulePath);
-  }
-
-  bool hasValueId(GlobalValue::GUID ValGUID) {
-    const auto &VMI = GUIDToValueIdMap.find(ValGUID);
-    return VMI != GUIDToValueIdMap.end();
-  }
-  unsigned getValueId(GlobalValue::GUID ValGUID) {
-    const auto &VMI = GUIDToValueIdMap.find(ValGUID);
-    // If this GUID doesn't have an entry, assign one.
-    if (VMI == GUIDToValueIdMap.end()) {
-      GUIDToValueIdMap[ValGUID] = ++GlobalValueId;
-      return GlobalValueId;
-    } else {
-      return VMI->second;
-    }
+  Optional<unsigned> getValueId(GlobalValue::GUID ValGUID) {
+    auto VMI = GUIDToValueIdMap.find(ValGUID);
+    if (VMI == GUIDToValueIdMap.end())
+      return None;
+    return VMI->second;
   }
   std::map<GlobalValue::GUID, unsigned> &valueIds() { return GUIDToValueIdMap; }
 };
@@ -570,14 +490,6 @@ static unsigned getEncodedOrdering(AtomicOrdering Ordering) {
   llvm_unreachable("Invalid ordering");
 }
 
-static unsigned getEncodedSynchScope(SynchronizationScope SynchScope) {
-  switch (SynchScope) {
-  case SingleThread: return bitc::SYNCHSCOPE_SINGLETHREAD;
-  case CrossThread: return bitc::SYNCHSCOPE_CROSSTHREAD;
-  }
-  llvm_unreachable("Invalid synch scope");
-}
-
 static void writeStringRecord(BitstreamWriter &Stream, unsigned Code,
                               StringRef Str, unsigned AbbrevToUse) {
   SmallVector<unsigned, 64> Vals;
@@ -671,6 +583,8 @@ static uint64_t getAttrKindEncoding(Attribute::AttrKind Kind) {
     return bitc::ATTR_KIND_RETURNS_TWICE;
   case Attribute::SExt:
     return bitc::ATTR_KIND_S_EXT;
+  case Attribute::Speculatable:
+    return bitc::ATTR_KIND_SPECULATABLE;
   case Attribute::StackAlignment:
     return bitc::ATTR_KIND_STACK_ALIGNMENT;
   case Attribute::StackProtect:
@@ -709,63 +623,62 @@ static uint64_t getAttrKindEncoding(Attribute::AttrKind Kind) {
 }
 
 void ModuleBitcodeWriter::writeAttributeGroupTable() {
-  const std::vector<AttributeSet> &AttrGrps = VE.getAttributeGroups();
+  const std::vector<ValueEnumerator::IndexAndAttrSet> &AttrGrps =
+      VE.getAttributeGroups();
   if (AttrGrps.empty()) return;
 
   Stream.EnterSubblock(bitc::PARAMATTR_GROUP_BLOCK_ID, 3);
 
   SmallVector<uint64_t, 64> Record;
-  for (unsigned i = 0, e = AttrGrps.size(); i != e; ++i) {
-    AttributeSet AS = AttrGrps[i];
-    for (unsigned i = 0, e = AS.getNumSlots(); i != e; ++i) {
-      AttributeSet A = AS.getSlotAttributes(i);
-
-      Record.push_back(VE.getAttributeGroupID(A));
-      Record.push_back(AS.getSlotIndex(i));
-
-      for (AttributeSet::iterator I = AS.begin(0), E = AS.end(0);
-           I != E; ++I) {
-        Attribute Attr = *I;
-        if (Attr.isEnumAttribute()) {
-          Record.push_back(0);
-          Record.push_back(getAttrKindEncoding(Attr.getKindAsEnum()));
-        } else if (Attr.isIntAttribute()) {
-          Record.push_back(1);
-          Record.push_back(getAttrKindEncoding(Attr.getKindAsEnum()));
-          Record.push_back(Attr.getValueAsInt());
-        } else {
-          StringRef Kind = Attr.getKindAsString();
-          StringRef Val = Attr.getValueAsString();
-
-          Record.push_back(Val.empty() ? 3 : 4);
-          Record.append(Kind.begin(), Kind.end());
+  for (ValueEnumerator::IndexAndAttrSet Pair : AttrGrps) {
+    unsigned AttrListIndex = Pair.first;
+    AttributeSet AS = Pair.second;
+    Record.push_back(VE.getAttributeGroupID(Pair));
+    Record.push_back(AttrListIndex);
+
+    for (Attribute Attr : AS) {
+      if (Attr.isEnumAttribute()) {
+        Record.push_back(0);
+        Record.push_back(getAttrKindEncoding(Attr.getKindAsEnum()));
+      } else if (Attr.isIntAttribute()) {
+        Record.push_back(1);
+        Record.push_back(getAttrKindEncoding(Attr.getKindAsEnum()));
+        Record.push_back(Attr.getValueAsInt());
+      } else {
+        StringRef Kind = Attr.getKindAsString();
+        StringRef Val = Attr.getValueAsString();
+
+        Record.push_back(Val.empty() ? 3 : 4);
+        Record.append(Kind.begin(), Kind.end());
+        Record.push_back(0);
+        if (!Val.empty()) {
+          Record.append(Val.begin(), Val.end());
           Record.push_back(0);
-          if (!Val.empty()) {
-            Record.append(Val.begin(), Val.end());
-            Record.push_back(0);
-          }
         }
       }
-
-      Stream.EmitRecord(bitc::PARAMATTR_GRP_CODE_ENTRY, Record);
-      Record.clear();
     }
+
+    Stream.EmitRecord(bitc::PARAMATTR_GRP_CODE_ENTRY, Record);
+    Record.clear();
   }
 
   Stream.ExitBlock();
 }
 
 void ModuleBitcodeWriter::writeAttributeTable() {
-  const std::vector<AttributeSet> &Attrs = VE.getAttributes();
+  const std::vector<AttributeList> &Attrs = VE.getAttributeLists();
   if (Attrs.empty()) return;
 
   Stream.EnterSubblock(bitc::PARAMATTR_BLOCK_ID, 3);
 
   SmallVector<uint64_t, 64> Record;
   for (unsigned i = 0, e = Attrs.size(); i != e; ++i) {
-    const AttributeSet &A = Attrs[i];
-    for (unsigned i = 0, e = A.getNumSlots(); i != e; ++i)
-      Record.push_back(VE.getAttributeGroupID(A.getSlotAttributes(i)));
+    AttributeList AL = Attrs[i];
+    for (unsigned i = AL.index_begin(), e = AL.index_end(); i != e; ++i) {
+      AttributeSet AS = AL.getAttributes(i);
+      if (AS.hasAttributes())
+        Record.push_back(VE.getAttributeGroupID({i, AS}));
+    }
 
     Stream.EmitRecord(bitc::PARAMATTR_CODE_ENTRY, Record);
     Record.clear();
@@ -972,7 +885,7 @@ static uint64_t getEncodedGVSummaryFlags(GlobalValueSummary::GVFlags Flags) {
   uint64_t RawFlags = 0;
 
   RawFlags |= Flags.NotEligibleToImport; // bool
-  RawFlags |= (Flags.LiveRoot << 1);
+  RawFlags |= (Flags.Live << 1);
   // Linkage don't need to be remapped at that time for the summary. Any future
   // change to the getEncodedLinkage() function will need to be taken into
   // account here as well.
@@ -1035,16 +948,19 @@ static unsigned getEncodedUnnamedAddr(const GlobalValue &GV) {
   llvm_unreachable("Invalid unnamed_addr");
 }
 
+size_t ModuleBitcodeWriter::addToStrtab(StringRef Str) {
+  if (GenerateHash)
+    Hasher.update(Str);
+  return StrtabBuilder.add(Str);
+}
+
 void ModuleBitcodeWriter::writeComdats() {
   SmallVector<unsigned, 64> Vals;
   for (const Comdat *C : VE.getComdats()) {
-    // COMDAT: [selection_kind, name]
+    // COMDAT: [strtab offset, strtab size, selection_kind]
+    Vals.push_back(addToStrtab(C->getName()));
+    Vals.push_back(C->getName().size());
     Vals.push_back(getEncodedComdatSelectionKind(*C));
-    size_t Size = C->getName().size();
-    assert(isUInt<32>(Size));
-    Vals.push_back(Size);
-    for (char Chr : C->getName())
-      Vals.push_back((unsigned char)Chr);
     Stream.EmitRecord(bitc::MODULE_CODE_COMDAT, Vals, /*AbbrevToUse=*/0);
     Vals.clear();
   }
@@ -1053,7 +969,7 @@ void ModuleBitcodeWriter::writeComdats() {
 /// Write a record that will eventually hold the word offset of the
 /// module-level VST. For now the offset is 0, which will be backpatched
 /// after the real VST is written. Saves the bit offset to backpatch.
-void BitcodeWriterBase::writeValueSymbolTableForwardDecl() {
+void ModuleBitcodeWriter::writeValueSymbolTableForwardDecl() {
   // Write a placeholder value in for the offset of the real VST,
   // which is written after the function blocks so that it can include
   // the offset of each function. The placeholder offset will be
@@ -1079,19 +995,18 @@ void BitcodeWriterBase::writeValueSymbolTableForwardDecl() {
 enum StringEncoding { SE_Char6, SE_Fixed7, SE_Fixed8 };
 
 /// Determine the encoding to use for the given string name and length.
-static StringEncoding getStringEncoding(const char *Str, unsigned StrLen) {
+static StringEncoding getStringEncoding(StringRef Str) {
   bool isChar6 = true;
-  for (const char *C = Str, *E = C + StrLen; C != E; ++C) {
+  for (char C : Str) {
     if (isChar6)
-      isChar6 = BitCodeAbbrevOp::isChar6(*C);
-    if ((unsigned char)*C & 128)
+      isChar6 = BitCodeAbbrevOp::isChar6(C);
+    if ((unsigned char)C & 128)
       // don't bother scanning the rest.
       return SE_Fixed8;
   }
   if (isChar6)
     return SE_Char6;
-  else
-    return SE_Fixed7;
+  return SE_Fixed7;
 }
 
 /// Emit top-level description of module, including target triple, inline asm,
@@ -1156,6 +1071,8 @@ void ModuleBitcodeWriter::writeModuleInfo() {
     // Add an abbrev for common globals with no visibility or thread localness.
     auto Abbv = std::make_shared<BitCodeAbbrev>();
     Abbv->Add(BitCodeAbbrevOp(bitc::MODULE_CODE_GLOBALVAR));
+    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
+    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
                               Log2_32_Ceil(MaxGlobalType+1)));
     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // AddrSpace << 2
@@ -1179,15 +1096,41 @@ void ModuleBitcodeWriter::writeModuleInfo() {
     SimpleGVarAbbrev = Stream.EmitAbbrev(std::move(Abbv));
   }
 
-  // Emit the global variable information.
   SmallVector<unsigned, 64> Vals;
+  // Emit the module's source file name.
+  {
+    StringEncoding Bits = getStringEncoding(M.getSourceFileName());
+    BitCodeAbbrevOp AbbrevOpToUse = BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8);
+    if (Bits == SE_Char6)
+      AbbrevOpToUse = BitCodeAbbrevOp(BitCodeAbbrevOp::Char6);
+    else if (Bits == SE_Fixed7)
+      AbbrevOpToUse = BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7);
+
+    // MODULE_CODE_SOURCE_FILENAME: [namechar x N]
+    auto Abbv = std::make_shared<BitCodeAbbrev>();
+    Abbv->Add(BitCodeAbbrevOp(bitc::MODULE_CODE_SOURCE_FILENAME));
+    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
+    Abbv->Add(AbbrevOpToUse);
+    unsigned FilenameAbbrev = Stream.EmitAbbrev(std::move(Abbv));
+
+    for (const auto P : M.getSourceFileName())
+      Vals.push_back((unsigned char)P);
+
+    // Emit the finished record.
+    Stream.EmitRecord(bitc::MODULE_CODE_SOURCE_FILENAME, Vals, FilenameAbbrev);
+    Vals.clear();
+  }
+
+  // Emit the global variable information.
   for (const GlobalVariable &GV : M.globals()) {
     unsigned AbbrevToUse = 0;
 
-    // GLOBALVAR: [type, isconst, initid,
+    // GLOBALVAR: [strtab offset, strtab size, type, isconst, initid,
     //             linkage, alignment, section, visibility, threadlocal,
     //             unnamed_addr, externally_initialized, dllstorageclass,
-    //             comdat]
+    //             comdat, attributes]
+    Vals.push_back(addToStrtab(GV.getName()));
+    Vals.push_back(GV.getName().size());
     Vals.push_back(VE.getTypeID(GV.getValueType()));
     Vals.push_back(GV.getType()->getAddressSpace() << 2 | 2 | GV.isConstant());
     Vals.push_back(GV.isDeclaration() ? 0 :
@@ -1200,13 +1143,17 @@ void ModuleBitcodeWriter::writeModuleInfo() {
         GV.getUnnamedAddr() != GlobalValue::UnnamedAddr::None ||
         GV.isExternallyInitialized() ||
         GV.getDLLStorageClass() != GlobalValue::DefaultStorageClass ||
-        GV.hasComdat()) {
+        GV.hasComdat() ||
+        GV.hasAttributes()) {
       Vals.push_back(getEncodedVisibility(GV));
       Vals.push_back(getEncodedThreadLocalMode(GV));
       Vals.push_back(getEncodedUnnamedAddr(GV));
       Vals.push_back(GV.isExternallyInitialized());
       Vals.push_back(getEncodedDLLStorageClass(GV));
       Vals.push_back(GV.hasComdat() ? VE.getComdatID(GV.getComdat()) : 0);
+
+      auto AL = GV.getAttributesAsList(AttributeList::FunctionIndex);
+      Vals.push_back(VE.getAttributeListID(AL));
     } else {
       AbbrevToUse = SimpleGVarAbbrev;
     }
@@ -1217,14 +1164,17 @@ void ModuleBitcodeWriter::writeModuleInfo() {
 
   // Emit the function proto information.
   for (const Function &F : M) {
-    // FUNCTION:  [type, callingconv, isproto, linkage, paramattrs, alignment,
-    //             section, visibility, gc, unnamed_addr, prologuedata,
-    //             dllstorageclass, comdat, prefixdata, personalityfn]
+    // FUNCTION:  [strtab offset, strtab size, type, callingconv, isproto,
+    //             linkage, paramattrs, alignment, section, visibility, gc,
+    //             unnamed_addr, prologuedata, dllstorageclass, comdat,
+    //             prefixdata, personalityfn]
+    Vals.push_back(addToStrtab(F.getName()));
+    Vals.push_back(F.getName().size());
     Vals.push_back(VE.getTypeID(F.getFunctionType()));
     Vals.push_back(F.getCallingConv());
     Vals.push_back(F.isDeclaration());
     Vals.push_back(getEncodedLinkage(F));
-    Vals.push_back(VE.getAttributeID(F.getAttributes()));
+    Vals.push_back(VE.getAttributeListID(F.getAttributes()));
     Vals.push_back(Log2_32(F.getAlignment())+1);
     Vals.push_back(F.hasSection() ? SectionMap[F.getSection()] : 0);
     Vals.push_back(getEncodedVisibility(F));
@@ -1246,8 +1196,10 @@ void ModuleBitcodeWriter::writeModuleInfo() {
 
   // Emit the alias information.
   for (const GlobalAlias &A : M.aliases()) {
-    // ALIAS: [alias type, aliasee val#, linkage, visibility, dllstorageclass,
-    //         threadlocal, unnamed_addr]
+    // ALIAS: [strtab offset, strtab size, alias type, aliasee val#, linkage,
+    //         visibility, dllstorageclass, threadlocal, unnamed_addr]
+    Vals.push_back(addToStrtab(A.getName()));
+    Vals.push_back(A.getName().size());
     Vals.push_back(VE.getTypeID(A.getValueType()));
     Vals.push_back(A.getType()->getAddressSpace());
     Vals.push_back(VE.getValueID(A.getAliasee()));
@@ -1263,7 +1215,10 @@ void ModuleBitcodeWriter::writeModuleInfo() {
 
   // Emit the ifunc information.
   for (const GlobalIFunc &I : M.ifuncs()) {
-    // IFUNC: [ifunc type, address space, resolver val#, linkage, visibility]
+    // IFUNC: [strtab offset, strtab size, ifunc type, address space, resolver
+    //         val#, linkage, visibility]
+    Vals.push_back(addToStrtab(I.getName()));
+    Vals.push_back(I.getName().size());
     Vals.push_back(VE.getTypeID(I.getValueType()));
     Vals.push_back(I.getType()->getAddressSpace());
     Vals.push_back(VE.getValueID(I.getResolver()));
@@ -1273,34 +1228,6 @@ void ModuleBitcodeWriter::writeModuleInfo() {
     Vals.clear();
   }
 
-  // Emit the module's source file name.
-  {
-    StringEncoding Bits = getStringEncoding(M.getSourceFileName().data(),
-                                            M.getSourceFileName().size());
-    BitCodeAbbrevOp AbbrevOpToUse = BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8);
-    if (Bits == SE_Char6)
-      AbbrevOpToUse = BitCodeAbbrevOp(BitCodeAbbrevOp::Char6);
-    else if (Bits == SE_Fixed7)
-      AbbrevOpToUse = BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7);
-
-    // MODULE_CODE_SOURCE_FILENAME: [namechar x N]
-    auto Abbv = std::make_shared<BitCodeAbbrev>();
-    Abbv->Add(BitCodeAbbrevOp(bitc::MODULE_CODE_SOURCE_FILENAME));
-    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
-    Abbv->Add(AbbrevOpToUse);
-    unsigned FilenameAbbrev = Stream.EmitAbbrev(std::move(Abbv));
-
-    for (const auto P : M.getSourceFileName())
-      Vals.push_back((unsigned char)P);
-
-    // Emit the finished record.
-    Stream.EmitRecord(bitc::MODULE_CODE_SOURCE_FILENAME, Vals, FilenameAbbrev);
-    Vals.clear();
-  }
-
-  // If we have a VST, write the VSTOFFSET record placeholder.
-  if (M.getValueSymbolTable().empty())
-    return;
   writeValueSymbolTableForwardDecl();
 }
 
@@ -1326,6 +1253,8 @@ static uint64_t getOptimizationFlags(const Value *V) {
       Flags |= FastMathFlags::NoSignedZeros;
     if (FPMO->hasAllowReciprocal())
       Flags |= FastMathFlags::AllowReciprocal;
+    if (FPMO->hasAllowContract())
+      Flags |= FastMathFlags::AllowContract;
   }
 
   return Flags;
@@ -1473,6 +1402,13 @@ void ModuleBitcodeWriter::writeDIDerivedType(const DIDerivedType *N,
   Record.push_back(N->getFlags());
   Record.push_back(VE.getMetadataOrNullID(N->getExtraData()));
 
+  // DWARF address space is encoded as N->getDWARFAddressSpace() + 1. 0 means
+  // that there is no DWARF address space associated with DIDerivedType.
+  if (const auto &DWARFAddressSpace = N->getDWARFAddressSpace())
+    Record.push_back(*DWARFAddressSpace + 1);
+  else
+    Record.push_back(0);
+
   Stream.EmitRecord(bitc::METADATA_DERIVED_TYPE, Record, Abbrev);
   Record.clear();
 }
@@ -1549,6 +1485,7 @@ void ModuleBitcodeWriter::writeDICompileUnit(const DICompileUnit *N,
   Record.push_back(N->getDWOId());
   Record.push_back(VE.getMetadataOrNullID(N->getMacros().get()));
   Record.push_back(N->getSplitDebugInlining());
+  Record.push_back(N->getDebugInfoForProfiling());
 
   Stream.EmitRecord(bitc::METADATA_COMPILE_UNIT, Record, Abbrev);
   Record.clear();
@@ -1578,6 +1515,7 @@ void ModuleBitcodeWriter::writeDISubprogram(const DISubprogram *N,
   Record.push_back(VE.getMetadataOrNullID(N->getDeclaration()));
   Record.push_back(VE.getMetadataOrNullID(N->getVariables().get()));
   Record.push_back(N->getThisAdjustment());
+  Record.push_back(VE.getMetadataOrNullID(N->getThrownTypes().get()));
 
   Stream.EmitRecord(bitc::METADATA_SUBPROGRAM, Record, Abbrev);
   Record.clear();
@@ -1613,9 +1551,7 @@ void ModuleBitcodeWriter::writeDINamespace(const DINamespace *N,
                                            unsigned Abbrev) {
   Record.push_back(N->isDistinct() | N->getExportSymbols() << 1);
   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
-  Record.push_back(VE.getMetadataOrNullID(N->getFile()));
   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
-  Record.push_back(N->getLine());
 
   Stream.EmitRecord(bitc::METADATA_NAMESPACE, Record, Abbrev);
   Record.clear();
@@ -1738,9 +1674,8 @@ void ModuleBitcodeWriter::writeDIExpression(const DIExpression *N,
                                             SmallVectorImpl<uint64_t> &Record,
                                             unsigned Abbrev) {
   Record.reserve(N->getElements().size() + 1);
-
-  const uint64_t HasOpFragmentFlag = 1 << 1;
-  Record.push_back((uint64_t)N->isDistinct() | HasOpFragmentFlag);
+  const uint64_t Version = 3 << 1;
+  Record.push_back((uint64_t)N->isDistinct() | Version);
   Record.append(N->elements_begin(), N->elements_end());
 
   Stream.EmitRecord(bitc::METADATA_EXPRESSION, Record, Abbrev);
@@ -1783,6 +1718,7 @@ void ModuleBitcodeWriter::writeDIImportedEntity(
   Record.push_back(VE.getMetadataOrNullID(N->getEntity()));
   Record.push_back(N->getLine());
   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
+  Record.push_back(VE.getMetadataOrNullID(N->getRawFile()));
 
   Stream.EmitRecord(bitc::METADATA_IMPORTED_ENTITY, Record, Abbrev);
   Record.clear();
@@ -2104,6 +2040,24 @@ void ModuleBitcodeWriter::writeOperandBundleTags() {
   Stream.ExitBlock();
 }
 
+void ModuleBitcodeWriter::writeSyncScopeNames() {
+  SmallVector<StringRef, 8> SSNs;
+  M.getContext().getSyncScopeNames(SSNs);
+  if (SSNs.empty())
+    return;
+
+  Stream.EnterSubblock(bitc::SYNC_SCOPE_NAMES_BLOCK_ID, 2);
+
+  SmallVector<uint64_t, 64> Record;
+  for (auto SSN : SSNs) {
+    Record.append(SSN.begin(), SSN.end());
+    Stream.EmitRecord(bitc::SYNC_SCOPE_NAME, Record, 0);
+    Record.clear();
+  }
+
+  Stream.ExitBlock();
+}
+
 static void emitSignedInt64(SmallVectorImpl<uint64_t> &Vals, uint64_t V) {
   if ((int64_t)V >= 0)
     Vals.push_back(V << 1);
@@ -2559,7 +2513,7 @@ void ModuleBitcodeWriter::writeInstruction(const Instruction &I,
       Vals.push_back(VE.getTypeID(SI.getCondition()->getType()));
       pushValue(SI.getCondition(), InstID, Vals);
       Vals.push_back(VE.getValueID(SI.getDefaultDest()));
-      for (SwitchInst::ConstCaseIt Case : SI.cases()) {
+      for (auto Case : SI.cases()) {
         Vals.push_back(VE.getValueID(Case.getCaseValue()));
         Vals.push_back(VE.getValueID(Case.getCaseSuccessor()));
       }
@@ -2584,7 +2538,7 @@ void ModuleBitcodeWriter::writeInstruction(const Instruction &I,
 
     Code = bitc::FUNC_CODE_INST_INVOKE;
 
-    Vals.push_back(VE.getAttributeID(II->getAttributes()));
+    Vals.push_back(VE.getAttributeListID(II->getAttributes()));
     Vals.push_back(II->getCallingConv() | 1 << 13);
     Vals.push_back(VE.getValueID(II->getNormalDest()));
     Vals.push_back(VE.getValueID(II->getUnwindDest()));
@@ -2720,7 +2674,7 @@ void ModuleBitcodeWriter::writeInstruction(const Instruction &I,
     Vals.push_back(cast<LoadInst>(I).isVolatile());
     if (cast<LoadInst>(I).isAtomic()) {
       Vals.push_back(getEncodedOrdering(cast<LoadInst>(I).getOrdering()));
-      Vals.push_back(getEncodedSynchScope(cast<LoadInst>(I).getSynchScope()));
+      Vals.push_back(getEncodedSyncScopeID(cast<LoadInst>(I).getSyncScopeID()));
     }
     break;
   case Instruction::Store:
@@ -2734,7 +2688,8 @@ void ModuleBitcodeWriter::writeInstruction(const Instruction &I,
     Vals.push_back(cast<StoreInst>(I).isVolatile());
     if (cast<StoreInst>(I).isAtomic()) {
       Vals.push_back(getEncodedOrdering(cast<StoreInst>(I).getOrdering()));
-      Vals.push_back(getEncodedSynchScope(cast<StoreInst>(I).getSynchScope()));
+      Vals.push_back(
+          getEncodedSyncScopeID(cast<StoreInst>(I).getSyncScopeID()));
     }
     break;
   case Instruction::AtomicCmpXchg:
@@ -2746,7 +2701,7 @@ void ModuleBitcodeWriter::writeInstruction(const Instruction &I,
     Vals.push_back(
         getEncodedOrdering(cast<AtomicCmpXchgInst>(I).getSuccessOrdering()));
     Vals.push_back(
-        getEncodedSynchScope(cast<AtomicCmpXchgInst>(I).getSynchScope()));
+        getEncodedSyncScopeID(cast<AtomicCmpXchgInst>(I).getSyncScopeID()));
     Vals.push_back(
         getEncodedOrdering(cast<AtomicCmpXchgInst>(I).getFailureOrdering()));
     Vals.push_back(cast<AtomicCmpXchgInst>(I).isWeak());
@@ -2760,12 +2715,12 @@ void ModuleBitcodeWriter::writeInstruction(const Instruction &I,
     Vals.push_back(cast<AtomicRMWInst>(I).isVolatile());
     Vals.push_back(getEncodedOrdering(cast<AtomicRMWInst>(I).getOrdering()));
     Vals.push_back(
-        getEncodedSynchScope(cast<AtomicRMWInst>(I).getSynchScope()));
+        getEncodedSyncScopeID(cast<AtomicRMWInst>(I).getSyncScopeID()));
     break;
   case Instruction::Fence:
     Code = bitc::FUNC_CODE_INST_FENCE;
     Vals.push_back(getEncodedOrdering(cast<FenceInst>(I).getOrdering()));
-    Vals.push_back(getEncodedSynchScope(cast<FenceInst>(I).getSynchScope()));
+    Vals.push_back(getEncodedSyncScopeID(cast<FenceInst>(I).getSyncScopeID()));
     break;
   case Instruction::Call: {
     const CallInst &CI = cast<CallInst>(I);
@@ -2776,7 +2731,7 @@ void ModuleBitcodeWriter::writeInstruction(const Instruction &I,
 
     Code = bitc::FUNC_CODE_INST_CALL;
 
-    Vals.push_back(VE.getAttributeID(CI.getAttributes()));
+    Vals.push_back(VE.getAttributeListID(CI.getAttributes()));
 
     unsigned Flags = getOptimizationFlags(&I);
     Vals.push_back(CI.getCallingConv() << bitc::CALL_CCONV |
@@ -2820,77 +2775,59 @@ void ModuleBitcodeWriter::writeInstruction(const Instruction &I,
   Vals.clear();
 }
 
-/// Emit names for globals/functions etc. \p IsModuleLevel is true when
-/// we are writing the module-level VST, where we are including a function
-/// bitcode index and need to backpatch the VST forward declaration record.
-void ModuleBitcodeWriter::writeValueSymbolTable(
-    const ValueSymbolTable &VST, bool IsModuleLevel,
-    DenseMap<const Function *, uint64_t> *FunctionToBitcodeIndex) {
-  if (VST.empty()) {
-    // writeValueSymbolTableForwardDecl should have returned early as
-    // well. Ensure this handling remains in sync by asserting that
-    // the placeholder offset is not set.
-    assert(!IsModuleLevel || !hasVSTOffsetPlaceholder());
-    return;
-  }
+/// Write a GlobalValue VST to the module. The purpose of this data structure is
+/// to allow clients to efficiently find the function body.
+void ModuleBitcodeWriter::writeGlobalValueSymbolTable(
+  DenseMap<const Function *, uint64_t> &FunctionToBitcodeIndex) {
+  // Get the offset of the VST we are writing, and backpatch it into
+  // the VST forward declaration record.
+  uint64_t VSTOffset = Stream.GetCurrentBitNo();
+  // The BitcodeStartBit was the stream offset of the identification block.
+  VSTOffset -= bitcodeStartBit();
+  assert((VSTOffset & 31) == 0 && "VST block not 32-bit aligned");
+  // Note that we add 1 here because the offset is relative to one word
+  // before the start of the identification block, which was historically
+  // always the start of the regular bitcode header.
+  Stream.BackpatchWord(VSTOffsetPlaceholder, VSTOffset / 32 + 1);
+
+  Stream.EnterSubblock(bitc::VALUE_SYMTAB_BLOCK_ID, 4);
+
+  auto Abbv = std::make_shared<BitCodeAbbrev>();
+  Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_FNENTRY));
+  Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // value id
+  Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // funcoffset
+  unsigned FnEntryAbbrev = Stream.EmitAbbrev(std::move(Abbv));
+
+  for (const Function &F : M) {
+    uint64_t Record[2];
 
-  if (IsModuleLevel && hasVSTOffsetPlaceholder()) {
-    // Get the offset of the VST we are writing, and backpatch it into
-    // the VST forward declaration record.
-    uint64_t VSTOffset = Stream.GetCurrentBitNo();
-    // The BitcodeStartBit was the stream offset of the identification block.
-    VSTOffset -= bitcodeStartBit();
-    assert((VSTOffset & 31) == 0 && "VST block not 32-bit aligned");
+    if (F.isDeclaration())
+      continue;
+
+    Record[0] = VE.getValueID(&F);
+
+    // Save the word offset of the function (from the start of the
+    // actual bitcode written to the stream).
+    uint64_t BitcodeIndex = FunctionToBitcodeIndex[&F] - bitcodeStartBit();
+    assert((BitcodeIndex & 31) == 0 && "function block not 32-bit aligned");
     // Note that we add 1 here because the offset is relative to one word
     // before the start of the identification block, which was historically
     // always the start of the regular bitcode header.
-    Stream.BackpatchWord(VSTOffsetPlaceholder, VSTOffset / 32 + 1);
-  }
-
-  Stream.EnterSubblock(bitc::VALUE_SYMTAB_BLOCK_ID, 4);
+    Record[1] = BitcodeIndex / 32 + 1;
 
-  // For the module-level VST, add abbrev Ids for the VST_CODE_FNENTRY
-  // records, which are not used in the per-function VSTs.
-  unsigned FnEntry8BitAbbrev;
-  unsigned FnEntry7BitAbbrev;
-  unsigned FnEntry6BitAbbrev;
-  unsigned GUIDEntryAbbrev;
-  if (IsModuleLevel && hasVSTOffsetPlaceholder()) {
-    // 8-bit fixed-width VST_CODE_FNENTRY function strings.
-    auto Abbv = std::make_shared<BitCodeAbbrev>();
-    Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_FNENTRY));
-    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // value id
-    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // funcoffset
-    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
-    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
-    FnEntry8BitAbbrev = Stream.EmitAbbrev(std::move(Abbv));
+    Stream.EmitRecord(bitc::VST_CODE_FNENTRY, Record, FnEntryAbbrev);
+  }
 
-    // 7-bit fixed width VST_CODE_FNENTRY function strings.
-    Abbv = std::make_shared<BitCodeAbbrev>();
-    Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_FNENTRY));
-    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // value id
-    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // funcoffset
-    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
-    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7));
-    FnEntry7BitAbbrev = Stream.EmitAbbrev(std::move(Abbv));
+  Stream.ExitBlock();
+}
 
-    // 6-bit char6 VST_CODE_FNENTRY function strings.
-    Abbv = std::make_shared<BitCodeAbbrev>();
-    Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_FNENTRY));
-    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // value id
-    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // funcoffset
-    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
-    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
-    FnEntry6BitAbbrev = Stream.EmitAbbrev(std::move(Abbv));
+/// Emit names for arguments, instructions and basic blocks in a function.
+void ModuleBitcodeWriter::writeFunctionLevelValueSymbolTable(
+    const ValueSymbolTable &VST) {
+  if (VST.empty())
+    return;
 
-    // FIXME: Change the name of this record as it is now used by
-    // the per-module index as well.
-    Abbv = std::make_shared<BitCodeAbbrev>();
-    Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_COMBINED_ENTRY));
-    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // valueid
-    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // refguid
-    GUIDEntryAbbrev = Stream.EmitAbbrev(std::move(Abbv));
-  }
+  Stream.EnterSubblock(bitc::VALUE_SYMTAB_BLOCK_ID, 4);
 
   // FIXME: Set up the abbrev, we know how many values there are!
   // FIXME: We know if the type names can use 7-bit ascii.
@@ -2898,51 +2835,18 @@ void ModuleBitcodeWriter::writeValueSymbolTable(
 
   for (const ValueName &Name : VST) {
     // Figure out the encoding to use for the name.
-    StringEncoding Bits =
-        getStringEncoding(Name.getKeyData(), Name.getKeyLength());
+    StringEncoding Bits = getStringEncoding(Name.getKey());
 
     unsigned AbbrevToUse = VST_ENTRY_8_ABBREV;
     NameVals.push_back(VE.getValueID(Name.getValue()));
 
-    Function *F = dyn_cast<Function>(Name.getValue());
-    if (!F) {
-      // If value is an alias, need to get the aliased base object to
-      // see if it is a function.
-      auto *GA = dyn_cast<GlobalAlias>(Name.getValue());
-      if (GA && GA->getBaseObject())
-        F = dyn_cast<Function>(GA->getBaseObject());
-    }
-
     // VST_CODE_ENTRY:   [valueid, namechar x N]
-    // VST_CODE_FNENTRY: [valueid, funcoffset, namechar x N]
     // VST_CODE_BBENTRY: [bbid, namechar x N]
     unsigned Code;
     if (isa<BasicBlock>(Name.getValue())) {
       Code = bitc::VST_CODE_BBENTRY;
       if (Bits == SE_Char6)
         AbbrevToUse = VST_BBENTRY_6_ABBREV;
-    } else if (F && !F->isDeclaration()) {
-      // Must be the module-level VST, where we pass in the Index and
-      // have a VSTOffsetPlaceholder. The function-level VST should not
-      // contain any Function symbols.
-      assert(FunctionToBitcodeIndex);
-      assert(hasVSTOffsetPlaceholder());
-
-      // Save the word offset of the function (from the start of the
-      // actual bitcode written to the stream).
-      uint64_t BitcodeIndex = (*FunctionToBitcodeIndex)[F] - bitcodeStartBit();
-      assert((BitcodeIndex & 31) == 0 && "function block not 32-bit aligned");
-      // Note that we add 1 here because the offset is relative to one word
-      // before the start of the identification block, which was historically
-      // always the start of the regular bitcode header.
-      NameVals.push_back(BitcodeIndex / 32 + 1);
-
-      Code = bitc::VST_CODE_FNENTRY;
-      AbbrevToUse = FnEntry8BitAbbrev;
-      if (Bits == SE_Char6)
-        AbbrevToUse = FnEntry6BitAbbrev;
-      else if (Bits == SE_Fixed7)
-        AbbrevToUse = FnEntry7BitAbbrev;
     } else {
       Code = bitc::VST_CODE_ENTRY;
       if (Bits == SE_Char6)
@@ -2958,47 +2862,7 @@ void ModuleBitcodeWriter::writeValueSymbolTable(
     Stream.EmitRecord(Code, NameVals, AbbrevToUse);
     NameVals.clear();
   }
-  // Emit any GUID valueIDs created for indirect call edges into the
-  // module-level VST.
-  if (IsModuleLevel && hasVSTOffsetPlaceholder())
-    for (const auto &GI : valueIds()) {
-      NameVals.push_back(GI.second);
-      NameVals.push_back(GI.first);
-      Stream.EmitRecord(bitc::VST_CODE_COMBINED_ENTRY, NameVals,
-                        GUIDEntryAbbrev);
-      NameVals.clear();
-    }
-  Stream.ExitBlock();
-}
-
-/// Emit function names and summary offsets for the combined index
-/// used by ThinLTO.
-void IndexBitcodeWriter::writeCombinedValueSymbolTable() {
-  assert(hasVSTOffsetPlaceholder() && "Expected non-zero VSTOffsetPlaceholder");
-  // Get the offset of the VST we are writing, and backpatch it into
-  // the VST forward declaration record.
-  uint64_t VSTOffset = Stream.GetCurrentBitNo();
-  assert((VSTOffset & 31) == 0 && "VST block not 32-bit aligned");
-  Stream.BackpatchWord(VSTOffsetPlaceholder, VSTOffset / 32);
 
-  Stream.EnterSubblock(bitc::VALUE_SYMTAB_BLOCK_ID, 4);
-
-  auto Abbv = std::make_shared<BitCodeAbbrev>();
-  Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_COMBINED_ENTRY));
-  Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // valueid
-  Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // refguid
-  unsigned EntryAbbrev = Stream.EmitAbbrev(std::move(Abbv));
-
-  SmallVector<uint64_t, 64> NameVals;
-  for (const auto &GVI : valueIds()) {
-    // VST_CODE_COMBINED_ENTRY: [valueid, refguid]
-    NameVals.push_back(GVI.second);
-    NameVals.push_back(GVI.first);
-
-    // Emit the finished record.
-    Stream.EmitRecord(bitc::VST_CODE_COMBINED_ENTRY, NameVals, EntryAbbrev);
-    NameVals.clear();
-  }
   Stream.ExitBlock();
 }
 
@@ -3102,7 +2966,7 @@ void ModuleBitcodeWriter::writeFunction(
 
   // Emit names for all the instructions etc.
   if (auto *Symtab = F.getValueSymbolTable())
-    writeValueSymbolTable(*Symtab);
+    writeFunctionLevelValueSymbolTable(*Symtab);
 
   if (NeedsMetadataAttachment)
     writeFunctionMetadataAttachment(F);
@@ -3329,42 +3193,77 @@ void IndexBitcodeWriter::writeModStrings() {
   unsigned AbbrevHash = Stream.EmitAbbrev(std::move(Abbv));
 
   SmallVector<unsigned, 64> Vals;
-  for (const auto &MPSE : Index.modulePaths()) {
-    if (!doIncludeModule(MPSE.getKey()))
-      continue;
-    StringEncoding Bits =
-        getStringEncoding(MPSE.getKey().data(), MPSE.getKey().size());
-    unsigned AbbrevToUse = Abbrev8Bit;
-    if (Bits == SE_Char6)
-      AbbrevToUse = Abbrev6Bit;
-    else if (Bits == SE_Fixed7)
-      AbbrevToUse = Abbrev7Bit;
+  forEachModule(
+      [&](const StringMapEntry<std::pair<uint64_t, ModuleHash>> &MPSE) {
+        StringRef Key = MPSE.getKey();
+        const auto &Value = MPSE.getValue();
+        StringEncoding Bits = getStringEncoding(Key);
+        unsigned AbbrevToUse = Abbrev8Bit;
+        if (Bits == SE_Char6)
+          AbbrevToUse = Abbrev6Bit;
+        else if (Bits == SE_Fixed7)
+          AbbrevToUse = Abbrev7Bit;
+
+        Vals.push_back(Value.first);
+        Vals.append(Key.begin(), Key.end());
+
+        // Emit the finished record.
+        Stream.EmitRecord(bitc::MST_CODE_ENTRY, Vals, AbbrevToUse);
+
+        // Emit an optional hash for the module now
+        const auto &Hash = Value.second;
+        if (llvm::any_of(Hash, [](uint32_t H) { return H; })) {
+          Vals.assign(Hash.begin(), Hash.end());
+          // Emit the hash record.
+          Stream.EmitRecord(bitc::MST_CODE_HASH, Vals, AbbrevHash);
+        }
 
-    Vals.push_back(MPSE.getValue().first);
+        Vals.clear();
+      });
+  Stream.ExitBlock();
+}
 
-    for (const auto P : MPSE.getKey())
-      Vals.push_back((unsigned char)P);
+/// Write the function type metadata related records that need to appear before
+/// a function summary entry (whether per-module or combined).
+static void writeFunctionTypeMetadataRecords(BitstreamWriter &Stream,
+                                             FunctionSummary *FS) {
+  if (!FS->type_tests().empty())
+    Stream.EmitRecord(bitc::FS_TYPE_TESTS, FS->type_tests());
 
-    // Emit the finished record.
-    Stream.EmitRecord(bitc::MST_CODE_ENTRY, Vals, AbbrevToUse);
+  SmallVector<uint64_t, 64> Record;
 
-    Vals.clear();
-    // Emit an optional hash for the module now
-    auto &Hash = MPSE.getValue().second;
-    bool AllZero = true; // Detect if the hash is empty, and do not generate it
-    for (auto Val : Hash) {
-      if (Val)
-        AllZero = false;
-      Vals.push_back(Val);
+  auto WriteVFuncIdVec = [&](uint64_t Ty,
+                             ArrayRef<FunctionSummary::VFuncId> VFs) {
+    if (VFs.empty())
+      return;
+    Record.clear();
+    for (auto &VF : VFs) {
+      Record.push_back(VF.GUID);
+      Record.push_back(VF.Offset);
     }
-    if (!AllZero) {
-      // Emit the hash record.
-      Stream.EmitRecord(bitc::MST_CODE_HASH, Vals, AbbrevHash);
+    Stream.EmitRecord(Ty, Record);
+  };
+
+  WriteVFuncIdVec(bitc::FS_TYPE_TEST_ASSUME_VCALLS,
+                  FS->type_test_assume_vcalls());
+  WriteVFuncIdVec(bitc::FS_TYPE_CHECKED_LOAD_VCALLS,
+                  FS->type_checked_load_vcalls());
+
+  auto WriteConstVCallVec = [&](uint64_t Ty,
+                                ArrayRef<FunctionSummary::ConstVCall> VCs) {
+    for (auto &VC : VCs) {
+      Record.clear();
+      Record.push_back(VC.VFunc.GUID);
+      Record.push_back(VC.VFunc.Offset);
+      Record.insert(Record.end(), VC.Args.begin(), VC.Args.end());
+      Stream.EmitRecord(Ty, Record);
     }
+  };
 
-    Vals.clear();
-  }
-  Stream.ExitBlock();
+  WriteConstVCallVec(bitc::FS_TYPE_TEST_ASSUME_CONST_VCALL,
+                     FS->type_test_assume_const_vcalls());
+  WriteConstVCallVec(bitc::FS_TYPE_CHECKED_LOAD_CONST_VCALL,
+                     FS->type_checked_load_const_vcalls());
 }
 
 // Helper to emit a single function summary record.
@@ -3375,8 +3274,7 @@ void ModuleBitcodeWriter::writePerModuleFunctionSummaryRecord(
   NameVals.push_back(ValueID);
 
   FunctionSummary *FS = cast<FunctionSummary>(Summary);
-  if (!FS->type_tests().empty())
-    Stream.EmitRecord(bitc::FS_TYPE_TESTS, FS->type_tests());
+  writeFunctionTypeMetadataRecords(Stream, FS);
 
   NameVals.push_back(getEncodedGVSummaryFlags(FS->flags()));
   NameVals.push_back(FS->instCount());
@@ -3406,15 +3304,14 @@ void ModuleBitcodeWriter::writePerModuleFunctionSummaryRecord(
 void ModuleBitcodeWriter::writeModuleLevelReferences(
     const GlobalVariable &V, SmallVector<uint64_t, 64> &NameVals,
     unsigned FSModRefsAbbrev) {
-  auto Summaries =
-      Index->findGlobalValueSummaryList(GlobalValue::getGUID(V.getName()));
-  if (Summaries == Index->end()) {
+  auto VI = Index->getValueInfo(GlobalValue::getGUID(V.getName()));
+  if (!VI || VI.getSummaryList().empty()) {
     // Only declarations should not have a summary (a declaration might however
     // have a summary if the def was in module level asm).
     assert(V.isDeclaration());
     return;
   }
-  auto *Summary = Summaries->second.front().get();
+  auto *Summary = VI.getSummaryList()[0].get();
   NameVals.push_back(VE.getValueID(&V));
   GlobalVarSummary *VS = cast<GlobalVarSummary>(Summary);
   NameVals.push_back(getEncodedGVSummaryFlags(VS->flags()));
@@ -3439,7 +3336,15 @@ static const uint64_t INDEX_VERSION = 3;
 /// Emit the per-module summary section alongside the rest of
 /// the module's bitcode.
 void ModuleBitcodeWriter::writePerModuleGlobalValueSummary() {
-  Stream.EnterSubblock(bitc::GLOBALVAL_SUMMARY_BLOCK_ID, 4);
+  // By default we compile with ThinLTO if the module has a summary, but the
+  // client can request full LTO with a module flag.
+  bool IsThinLTO = true;
+  if (auto *MD =
+          mdconst::extract_or_null<ConstantInt>(M.getModuleFlag("ThinLTO")))
+    IsThinLTO = MD->getZExtValue();
+  Stream.EnterSubblock(IsThinLTO ? bitc::GLOBALVAL_SUMMARY_BLOCK_ID
+                                 : bitc::FULL_LTO_GLOBALVAL_SUMMARY_BLOCK_ID,
+                       4);
 
   Stream.EmitRecord(bitc::FS_VERSION, ArrayRef<uint64_t>{INDEX_VERSION});
 
@@ -3448,6 +3353,11 @@ void ModuleBitcodeWriter::writePerModuleGlobalValueSummary() {
     return;
   }
 
+  for (const auto &GVI : valueIds()) {
+    Stream.EmitRecord(bitc::FS_VALUE_GUID,
+                      ArrayRef<uint64_t>{GVI.second, GVI.first});
+  }
+
   // Abbrev for FS_PERMODULE.
   auto Abbv = std::make_shared<BitCodeAbbrev>();
   Abbv->Add(BitCodeAbbrevOp(bitc::FS_PERMODULE));
@@ -3498,15 +3408,14 @@ void ModuleBitcodeWriter::writePerModuleGlobalValueSummary() {
     if (!F.hasName())
       report_fatal_error("Unexpected anonymous function when writing summary");
 
-    auto Summaries =
-        Index->findGlobalValueSummaryList(GlobalValue::getGUID(F.getName()));
-    if (Summaries == Index->end()) {
+    ValueInfo VI = Index->getValueInfo(GlobalValue::getGUID(F.getName()));
+    if (!VI || VI.getSummaryList().empty()) {
       // Only declarations should not have a summary (a declaration might
       // however have a summary if the def was in module level asm).
       assert(F.isDeclaration());
       continue;
     }
-    auto *Summary = Summaries->second.front().get();
+    auto *Summary = VI.getSummaryList()[0].get();
     writePerModuleFunctionSummaryRecord(NameVals, Summary, VE.getValueID(&F),
                                         FSCallsAbbrev, FSCallsProfileAbbrev, F);
   }
@@ -3540,6 +3449,11 @@ void IndexBitcodeWriter::writeCombinedGlobalValueSummary() {
   Stream.EnterSubblock(bitc::GLOBALVAL_SUMMARY_BLOCK_ID, 3);
   Stream.EmitRecord(bitc::FS_VERSION, ArrayRef<uint64_t>{INDEX_VERSION});
 
+  for (const auto &GVI : valueIds()) {
+    Stream.EmitRecord(bitc::FS_VALUE_GUID,
+                      ArrayRef<uint64_t>{GVI.second, GVI.first});
+  }
+
   // Abbrev for FS_COMBINED.
   auto Abbv = std::make_shared<BitCodeAbbrev>();
   Abbv->Add(BitCodeAbbrevOp(bitc::FS_COMBINED));
@@ -3604,27 +3518,30 @@ void IndexBitcodeWriter::writeCombinedGlobalValueSummary() {
     NameVals.clear();
   };
 
-  for (const auto &I : *this) {
+  forEachSummary([&](GVInfo I) {
     GlobalValueSummary *S = I.second;
     assert(S);
 
-    assert(hasValueId(I.first));
-    unsigned ValueId = getValueId(I.first);
-    SummaryToValueIdMap[S] = ValueId;
+    auto ValueId = getValueId(I.first);
+    assert(ValueId);
+    SummaryToValueIdMap[S] = *ValueId;
 
     if (auto *AS = dyn_cast<AliasSummary>(S)) {
       // Will process aliases as a post-pass because the reader wants all
       // global to be loaded first.
       Aliases.push_back(AS);
-      continue;
+      return;
     }
 
     if (auto *VS = dyn_cast<GlobalVarSummary>(S)) {
-      NameVals.push_back(ValueId);
+      NameVals.push_back(*ValueId);
       NameVals.push_back(Index.getModuleId(VS->modulePath()));
       NameVals.push_back(getEncodedGVSummaryFlags(VS->flags()));
       for (auto &RI : VS->refs()) {
-        NameVals.push_back(getValueId(RI.getGUID()));
+        auto RefValueId = getValueId(RI.getGUID());
+        if (!RefValueId)
+          continue;
+        NameVals.push_back(*RefValueId);
       }
 
       // Emit the finished record.
@@ -3632,22 +3549,28 @@ void IndexBitcodeWriter::writeCombinedGlobalValueSummary() {
                         FSModRefsAbbrev);
       NameVals.clear();
       MaybeEmitOriginalName(*S);
-      continue;
+      return;
     }
 
     auto *FS = cast<FunctionSummary>(S);
-    if (!FS->type_tests().empty())
-      Stream.EmitRecord(bitc::FS_TYPE_TESTS, FS->type_tests());
+    writeFunctionTypeMetadataRecords(Stream, FS);
 
-    NameVals.push_back(ValueId);
+    NameVals.push_back(*ValueId);
     NameVals.push_back(Index.getModuleId(FS->modulePath()));
     NameVals.push_back(getEncodedGVSummaryFlags(FS->flags()));
     NameVals.push_back(FS->instCount());
-    NameVals.push_back(FS->refs().size());
+    // Fill in below
+    NameVals.push_back(0);
 
+    unsigned Count = 0;
     for (auto &RI : FS->refs()) {
-      NameVals.push_back(getValueId(RI.getGUID()));
+      auto RefValueId = getValueId(RI.getGUID());
+      if (!RefValueId)
+        continue;
+      NameVals.push_back(*RefValueId);
+      Count++;
     }
+    NameVals[4] = Count;
 
     bool HasProfileData = false;
     for (auto &EI : FS->calls()) {
@@ -3659,9 +3582,20 @@ void IndexBitcodeWriter::writeCombinedGlobalValueSummary() {
     for (auto &EI : FS->calls()) {
       // If this GUID doesn't have a value id, it doesn't have a function
       // summary and we don't need to record any calls to it.
-      if (!hasValueId(EI.first.getGUID()))
-        continue;
-      NameVals.push_back(getValueId(EI.first.getGUID()));
+      GlobalValue::GUID GUID = EI.first.getGUID();
+      auto CallValueId = getValueId(GUID);
+      if (!CallValueId) {
+        // For SamplePGO, the indirect call targets for local functions will
+        // have its original name annotated in profile. We try to find the
+        // corresponding PGOFuncName as the GUID.
+        GUID = Index.getGUIDFromOriginalID(GUID);
+        if (GUID == 0)
+          continue;
+        CallValueId = getValueId(GUID);
+        if (!CallValueId)
+          continue;
+      }
+      NameVals.push_back(*CallValueId);
       if (HasProfileData)
         NameVals.push_back(static_cast<uint8_t>(EI.second.Hotness));
     }
@@ -3674,7 +3608,7 @@ void IndexBitcodeWriter::writeCombinedGlobalValueSummary() {
     Stream.EmitRecord(Code, NameVals, FSAbbrev);
     NameVals.clear();
     MaybeEmitOriginalName(*S);
-  }
+  });
 
   for (auto *AS : Aliases) {
     auto AliasValueId = SummaryToValueIdMap[AS];
@@ -3692,12 +3626,30 @@ void IndexBitcodeWriter::writeCombinedGlobalValueSummary() {
     MaybeEmitOriginalName(*AS);
   }
 
+  if (!Index.cfiFunctionDefs().empty()) {
+    for (auto &S : Index.cfiFunctionDefs()) {
+      NameVals.push_back(StrtabBuilder.add(S));
+      NameVals.push_back(S.size());
+    }
+    Stream.EmitRecord(bitc::FS_CFI_FUNCTION_DEFS, NameVals);
+    NameVals.clear();
+  }
+
+  if (!Index.cfiFunctionDecls().empty()) {
+    for (auto &S : Index.cfiFunctionDecls()) {
+      NameVals.push_back(StrtabBuilder.add(S));
+      NameVals.push_back(S.size());
+    }
+    Stream.EmitRecord(bitc::FS_CFI_FUNCTION_DECLS, NameVals);
+    NameVals.clear();
+  }
+
   Stream.ExitBlock();
 }
 
 /// Create the "IDENTIFICATION_BLOCK_ID" containing a single string with the
 /// current llvm version, and a record for the epoch number.
-void writeIdentificationBlock(BitstreamWriter &Stream) {
+static void writeIdentificationBlock(BitstreamWriter &Stream) {
   Stream.EnterSubblock(bitc::IDENTIFICATION_BLOCK_ID, 5);
 
   // Write the "user readable" string identifying the bitcode producer
@@ -3722,17 +3674,23 @@ void writeIdentificationBlock(BitstreamWriter &Stream) {
 void ModuleBitcodeWriter::writeModuleHash(size_t BlockStartPos) {
   // Emit the module's hash.
   // MODULE_CODE_HASH: [5*i32]
-  SHA1 Hasher;
-  Hasher.update(ArrayRef<uint8_t>((const uint8_t *)&(Buffer)[BlockStartPos],
-                                  Buffer.size() - BlockStartPos));
-  StringRef Hash = Hasher.result();
-  uint32_t Vals[5];
-  for (int Pos = 0; Pos < 20; Pos += 4) {
-    Vals[Pos / 4] = support::endian::read32be(Hash.data() + Pos);
-  }
+  if (GenerateHash) {
+    uint32_t Vals[5];
+    Hasher.update(ArrayRef<uint8_t>((const uint8_t *)&(Buffer)[BlockStartPos],
+                                    Buffer.size() - BlockStartPos));
+    StringRef Hash = Hasher.result();
+    for (int Pos = 0; Pos < 20; Pos += 4) {
+      Vals[Pos / 4] = support::endian::read32be(Hash.data() + Pos);
+    }
 
-  // Emit the finished record.
-  Stream.EmitRecord(bitc::MODULE_CODE_HASH, Vals);
+    // Emit the finished record.
+    Stream.EmitRecord(bitc::MODULE_CODE_HASH, Vals);
+
+    if (ModHash)
+      // Save the written hash value.
+      std::copy(std::begin(Vals), std::end(Vals), std::begin(*ModHash));
+  } else if (ModHash)
+    Stream.EmitRecord(bitc::MODULE_CODE_HASH, ArrayRef<uint32_t>(*ModHash));
 }
 
 void ModuleBitcodeWriter::write() {
@@ -3741,10 +3699,7 @@ void ModuleBitcodeWriter::write() {
   Stream.EnterSubblock(bitc::MODULE_BLOCK_ID, 3);
   size_t BlockStartPos = Buffer.size();
 
-  SmallVector<unsigned, 1> Vals;
-  unsigned CurVersion = 1;
-  Vals.push_back(CurVersion);
-  Stream.EmitRecord(bitc::MODULE_CODE_VERSION, Vals);
+  writeModuleVersion();
 
   // Emit blockinfo, which defines the standard abbreviations etc.
   writeBlockInfo();
@@ -3778,6 +3733,7 @@ void ModuleBitcodeWriter::write() {
     writeUseListBlock(nullptr);
 
   writeOperandBundleTags();
+  writeSyncScopeNames();
 
   // Emit function bodies.
   DenseMap<const Function *, uint64_t> FunctionToBitcodeIndex;
@@ -3790,12 +3746,9 @@ void ModuleBitcodeWriter::write() {
   if (Index)
     writePerModuleGlobalValueSummary();
 
-  writeValueSymbolTable(M.getValueSymbolTable(),
-                        /* IsModuleLevel */ true, &FunctionToBitcodeIndex);
+  writeGlobalValueSymbolTable(FunctionToBitcodeIndex);
 
-  if (GenerateHash) {
-    writeModuleHash(BlockStartPos);
-  }
+  writeModuleHash(BlockStartPos);
 
   Stream.ExitBlock();
 }
@@ -3881,23 +3834,105 @@ BitcodeWriter::BitcodeWriter(SmallVectorImpl<char> &Buffer)
   writeBitcodeHeader(*Stream);
 }
 
-BitcodeWriter::~BitcodeWriter() = default;
+BitcodeWriter::~BitcodeWriter() { assert(WroteStrtab); }
+
+void BitcodeWriter::writeBlob(unsigned Block, unsigned Record, StringRef Blob) {
+  Stream->EnterSubblock(Block, 3);
+
+  auto Abbv = std::make_shared<BitCodeAbbrev>();
+  Abbv->Add(BitCodeAbbrevOp(Record));
+  Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Blob));
+  auto AbbrevNo = Stream->EmitAbbrev(std::move(Abbv));
+
+  Stream->EmitRecordWithBlob(AbbrevNo, ArrayRef<uint64_t>{Record}, Blob);
+
+  Stream->ExitBlock();
+}
+
+void BitcodeWriter::writeSymtab() {
+  assert(!WroteStrtab && !WroteSymtab);
+
+  // If any module has module-level inline asm, we will require a registered asm
+  // parser for the target so that we can create an accurate symbol table for
+  // the module.
+  for (Module *M : Mods) {
+    if (M->getModuleInlineAsm().empty())
+      continue;
+
+    std::string Err;
+    const Triple TT(M->getTargetTriple());
+    const Target *T = TargetRegistry::lookupTarget(TT.str(), Err);
+    if (!T || !T->hasMCAsmParser())
+      return;
+  }
+
+  WroteSymtab = true;
+  SmallVector<char, 0> Symtab;
+  // The irsymtab::build function may be unable to create a symbol table if the
+  // module is malformed (e.g. it contains an invalid alias). Writing a symbol
+  // table is not required for correctness, but we still want to be able to
+  // write malformed modules to bitcode files, so swallow the error.
+  if (Error E = irsymtab::build(Mods, Symtab, StrtabBuilder, Alloc)) {
+    consumeError(std::move(E));
+    return;
+  }
+
+  writeBlob(bitc::SYMTAB_BLOCK_ID, bitc::SYMTAB_BLOB,
+            {Symtab.data(), Symtab.size()});
+}
+
+void BitcodeWriter::writeStrtab() {
+  assert(!WroteStrtab);
+
+  std::vector<char> Strtab;
+  StrtabBuilder.finalizeInOrder();
+  Strtab.resize(StrtabBuilder.getSize());
+  StrtabBuilder.write((uint8_t *)Strtab.data());
+
+  writeBlob(bitc::STRTAB_BLOCK_ID, bitc::STRTAB_BLOB,
+            {Strtab.data(), Strtab.size()});
+
+  WroteStrtab = true;
+}
+
+void BitcodeWriter::copyStrtab(StringRef Strtab) {
+  writeBlob(bitc::STRTAB_BLOCK_ID, bitc::STRTAB_BLOB, Strtab);
+  WroteStrtab = true;
+}
 
 void BitcodeWriter::writeModule(const Module *M,
                                 bool ShouldPreserveUseListOrder,
                                 const ModuleSummaryIndex *Index,
-                                bool GenerateHash) {
-  ModuleBitcodeWriter ModuleWriter(
-      M, Buffer, *Stream, ShouldPreserveUseListOrder, Index, GenerateHash);
+                                bool GenerateHash, ModuleHash *ModHash) {
+  assert(!WroteStrtab);
+
+  // The Mods vector is used by irsymtab::build, which requires non-const
+  // Modules in case it needs to materialize metadata. But the bitcode writer
+  // requires that the module is materialized, so we can cast to non-const here,
+  // after checking that it is in fact materialized.
+  assert(M->isMaterialized());
+  Mods.push_back(const_cast<Module *>(M));
+
+  ModuleBitcodeWriter ModuleWriter(M, Buffer, StrtabBuilder, *Stream,
+                                   ShouldPreserveUseListOrder, Index,
+                                   GenerateHash, ModHash);
   ModuleWriter.write();
 }
 
+void BitcodeWriter::writeIndex(
+    const ModuleSummaryIndex *Index,
+    const std::map<std::string, GVSummaryMapTy> *ModuleToSummariesForIndex) {
+  IndexBitcodeWriter IndexWriter(*Stream, StrtabBuilder, *Index,
+                                 ModuleToSummariesForIndex);
+  IndexWriter.write();
+}
+
 /// WriteBitcodeToFile - Write the specified module to the specified output
 /// stream.
 void llvm::WriteBitcodeToFile(const Module *M, raw_ostream &Out,
                               bool ShouldPreserveUseListOrder,
                               const ModuleSummaryIndex *Index,
-                              bool GenerateHash) {
+                              bool GenerateHash, ModuleHash *ModHash) {
   SmallVector<char, 0> Buffer;
   Buffer.reserve(256*1024);
 
@@ -3908,7 +3943,10 @@ void llvm::WriteBitcodeToFile(const Module *M, raw_ostream &Out,
     Buffer.insert(Buffer.begin(), BWH_HeaderSize, 0);
 
   BitcodeWriter Writer(Buffer);
-  Writer.writeModule(M, ShouldPreserveUseListOrder, Index, GenerateHash);
+  Writer.writeModule(M, ShouldPreserveUseListOrder, Index, GenerateHash,
+                     ModHash);
+  Writer.writeSymtab();
+  Writer.writeStrtab();
 
   if (TT.isOSDarwin() || TT.isOSBinFormatMachO())
     emitDarwinBCHeaderAndTrailer(Buffer, TT);
@@ -3920,13 +3958,7 @@ void llvm::WriteBitcodeToFile(const Module *M, raw_ostream &Out,
 void IndexBitcodeWriter::write() {
   Stream.EnterSubblock(bitc::MODULE_BLOCK_ID, 3);
 
-  SmallVector<unsigned, 1> Vals;
-  unsigned CurVersion = 1;
-  Vals.push_back(CurVersion);
-  Stream.EmitRecord(bitc::MODULE_CODE_VERSION, Vals);
-
-  // If we have a VST, write the VSTOFFSET record placeholder.
-  writeValueSymbolTableForwardDecl();
+  writeModuleVersion();
 
   // Write the module paths in the combined index.
   writeModStrings();
@@ -3934,10 +3966,6 @@ void IndexBitcodeWriter::write() {
   // Write the summary combined index records.
   writeCombinedGlobalValueSummary();
 
-  // Need a special VST writer for the combined index (we don't have a
-  // real VST and real values when this is invoked).
-  writeCombinedValueSymbolTable();
-
   Stream.ExitBlock();
 }
 
@@ -3951,11 +3979,9 @@ void llvm::WriteIndexToFile(
   SmallVector<char, 0> Buffer;
   Buffer.reserve(256 * 1024);
 
-  BitstreamWriter Stream(Buffer);
-  writeBitcodeHeader(Stream);
-
-  IndexBitcodeWriter IndexWriter(Stream, Index, ModuleToSummariesForIndex);
-  IndexWriter.write();
+  BitcodeWriter Writer(Buffer);
+  Writer.writeIndex(&Index, ModuleToSummariesForIndex);
+  Writer.writeStrtab();
 
   Out.write((char *)&Buffer.front(), Buffer.size());
 }
diff --git a/contrib/llvm/lib/Bitcode/Writer/ValueEnumerator.cpp b/contrib/llvm/lib/Bitcode/Writer/ValueEnumerator.cpp
index 5d5bfab..bb626ba 100644
--- a/contrib/llvm/lib/Bitcode/Writer/ValueEnumerator.cpp
+++ b/contrib/llvm/lib/Bitcode/Writer/ValueEnumerator.cpp
@@ -314,10 +314,13 @@ ValueEnumerator::ValueEnumerator(const Module &M,
   // Remember what is the cutoff between globalvalue's and other constants.
   unsigned FirstConstant = Values.size();
 
-  // Enumerate the global variable initializers.
-  for (const GlobalVariable &GV : M.globals())
+  // Enumerate the global variable initializers and attributes.
+  for (const GlobalVariable &GV : M.globals()) {
     if (GV.hasInitializer())
       EnumerateValue(GV.getInitializer());
+    if (GV.hasAttributes())
+      EnumerateAttributes(GV.getAttributesAsList(AttributeList::FunctionIndex));
+  }
 
   // Enumerate the aliasees.
   for (const GlobalAlias &GA : M.aliases())
@@ -432,12 +435,14 @@ unsigned ValueEnumerator::getValueID(const Value *V) const {
   return I->second-1;
 }
 
+#if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
 LLVM_DUMP_METHOD void ValueEnumerator::dump() const {
   print(dbgs(), ValueMap, "Default");
   dbgs() << '\n';
   print(dbgs(), MetadataMap, "MetaData");
   dbgs() << '\n';
 }
+#endif
 
 void ValueEnumerator::print(raw_ostream &OS, const ValueMapType &Map,
                             const char *Name) const {
@@ -452,7 +457,8 @@ void ValueEnumerator::print(raw_ostream &OS, const ValueMapType &Map,
       OS << "Value: " << V->getName();
     else
       OS << "Value: [null]\n";
-    V->dump();
+    V->print(errs());
+    errs() << '\n';
 
     OS << " Uses(" << std::distance(V->use_begin(),V->use_end()) << "):";
     for (const Use &U : V->uses()) {
@@ -549,7 +555,7 @@ void ValueEnumerator::EnumerateFunctionLocalMetadata(
 void ValueEnumerator::dropFunctionFromMetadata(
     MetadataMapType::value_type &FirstMD) {
   SmallVector<const MDNode *, 64> Worklist;
-  auto push = [this, &Worklist](MetadataMapType::value_type &MD) {
+  auto push = [&Worklist](MetadataMapType::value_type &MD) {
     auto &Entry = MD.second;
 
     // Nothing to do if this metadata isn't tagged.
@@ -884,23 +890,26 @@ void ValueEnumerator::EnumerateOperandType(const Value *V) {
   }
 }
 
-void ValueEnumerator::EnumerateAttributes(AttributeSet PAL) {
+void ValueEnumerator::EnumerateAttributes(AttributeList PAL) {
   if (PAL.isEmpty()) return;  // null is always 0.
 
   // Do a lookup.
-  unsigned &Entry = AttributeMap[PAL];
+  unsigned &Entry = AttributeListMap[PAL];
   if (Entry == 0) {
     // Never saw this before, add it.
-    Attribute.push_back(PAL);
-    Entry = Attribute.size();
+    AttributeLists.push_back(PAL);
+    Entry = AttributeLists.size();
   }
 
   // Do lookups for all attribute groups.
-  for (unsigned i = 0, e = PAL.getNumSlots(); i != e; ++i) {
-    AttributeSet AS = PAL.getSlotAttributes(i);
-    unsigned &Entry = AttributeGroupMap[AS];
+  for (unsigned i = PAL.index_begin(), e = PAL.index_end(); i != e; ++i) {
+    AttributeSet AS = PAL.getAttributes(i);
+    if (!AS.hasAttributes())
+      continue;
+    IndexAndAttrSet Pair = {i, AS};
+    unsigned &Entry = AttributeGroupMap[Pair];
     if (Entry == 0) {
-      AttributeGroups.push_back(AS);
+      AttributeGroups.push_back(Pair);
       Entry = AttributeGroups.size();
     }
   }
diff --git a/contrib/llvm/lib/Bitcode/Writer/ValueEnumerator.h b/contrib/llvm/lib/Bitcode/Writer/ValueEnumerator.h
index a8d6cf9..e7ccc8d 100644
--- a/contrib/llvm/lib/Bitcode/Writer/ValueEnumerator.h
+++ b/contrib/llvm/lib/Bitcode/Writer/ValueEnumerator.h
@@ -36,7 +36,7 @@ class LocalAsMetadata;
 class MDNode;
 class MDOperand;
 class NamedMDNode;
-class AttributeSet;
+class AttributeList;
 class ValueSymbolTable;
 class MDSymbolTable;
 class raw_ostream;
@@ -48,6 +48,10 @@ public:
   // For each value, we remember its Value* and occurrence frequency.
   typedef std::vector<std::pair<const Value*, unsigned> > ValueList;
 
+  /// Attribute groups as encoded in bitcode are almost AttributeSets, but they
+  /// include the AttributeList index, so we have to track that in our map.
+  typedef std::pair<unsigned, AttributeSet> IndexAndAttrSet;
+
   UseListOrderStack UseListOrders;
 
 private:
@@ -102,13 +106,13 @@ private:
 
   bool ShouldPreserveUseListOrder;
 
-  typedef DenseMap<AttributeSet, unsigned> AttributeGroupMapType;
+  typedef DenseMap<IndexAndAttrSet, unsigned> AttributeGroupMapType;
   AttributeGroupMapType AttributeGroupMap;
-  std::vector<AttributeSet> AttributeGroups;
+  std::vector<IndexAndAttrSet> AttributeGroups;
 
-  typedef DenseMap<AttributeSet, unsigned> AttributeMapType;
-  AttributeMapType AttributeMap;
-  std::vector<AttributeSet> Attribute;
+  typedef DenseMap<AttributeList, unsigned> AttributeListMapType;
+  AttributeListMapType AttributeListMap;
+  std::vector<AttributeList> AttributeLists;
 
   /// GlobalBasicBlockIDs - This map memoizes the basic block ID's referenced by
   /// the "getGlobalBasicBlockID" method.
@@ -166,16 +170,17 @@ public:
   unsigned getInstructionID(const Instruction *I) const;
   void setInstructionID(const Instruction *I);
 
-  unsigned getAttributeID(AttributeSet PAL) const {
+  unsigned getAttributeListID(AttributeList PAL) const {
     if (PAL.isEmpty()) return 0;  // Null maps to zero.
-    AttributeMapType::const_iterator I = AttributeMap.find(PAL);
-    assert(I != AttributeMap.end() && "Attribute not in ValueEnumerator!");
+    AttributeListMapType::const_iterator I = AttributeListMap.find(PAL);
+    assert(I != AttributeListMap.end() && "Attribute not in ValueEnumerator!");
     return I->second;
   }
 
-  unsigned getAttributeGroupID(AttributeSet PAL) const {
-    if (PAL.isEmpty()) return 0;  // Null maps to zero.
-    AttributeGroupMapType::const_iterator I = AttributeGroupMap.find(PAL);
+  unsigned getAttributeGroupID(IndexAndAttrSet Group) const {
+    if (!Group.second.hasAttributes())
+      return 0; // Null maps to zero.
+    AttributeGroupMapType::const_iterator I = AttributeGroupMap.find(Group);
     assert(I != AttributeGroupMap.end() && "Attribute not in ValueEnumerator!");
     return I->second;
   }
@@ -206,10 +211,8 @@ public:
   const std::vector<const BasicBlock*> &getBasicBlocks() const {
     return BasicBlocks;
   }
-  const std::vector<AttributeSet> &getAttributes() const {
-    return Attribute;
-  }
-  const std::vector<AttributeSet> &getAttributeGroups() const {
+  const std::vector<AttributeList> &getAttributeLists() const { return AttributeLists; }
+  const std::vector<IndexAndAttrSet> &getAttributeGroups() const {
     return AttributeGroups;
   }
 
@@ -283,7 +286,7 @@ private:
   void EnumerateValue(const Value *V);
   void EnumerateType(Type *T);
   void EnumerateOperandType(const Value *V);
-  void EnumerateAttributes(AttributeSet PAL);
+  void EnumerateAttributes(AttributeList PAL);
 
   void EnumerateValueSymbolTable(const ValueSymbolTable &ST);
   void EnumerateNamedMetadata(const Module &M);