vendor/llvm-project/llvmorg-12-init-17869-g8e464dd76bef

10 files changed, 1342 insertions, 385 deletions

diff --git a/llvm/lib/TableGen/DetailedRecordsBackend.cpp b/llvm/lib/TableGen/DetailedRecordsBackend.cpp
new file mode 100644
index 000000000000..2c3c3358b347
--- /dev/null
+++ b/llvm/lib/TableGen/DetailedRecordsBackend.cpp
@@ -0,0 +1,203 @@
+//===- DetailedRecordBackend.cpp - Detailed Records Report      -*- C++ -*-===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+//
+// This Tablegen backend prints a report that includes all the global 
+// variables, classes, and records in complete detail. It includes more
+// detail than the default TableGen printer backend.
+//
+//===----------------------------------------------------------------------===//
+
+#include "llvm/ADT/ArrayRef.h"
+#include "llvm/ADT/DenseMap.h"
+#include "llvm/ADT/StringExtras.h"
+#include "llvm/Support/Format.h"
+#include "llvm/Support/FormatVariadic.h"
+#include "llvm/Support/MemoryBuffer.h"
+#include "llvm/Support/SourceMgr.h"
+#include "llvm/TableGen/Error.h"
+#include "llvm/TableGen/Record.h"
+#include "llvm/TableGen/TableGenBackend.h"
+#include <algorithm>
+#include <set>
+#include <string>
+#include <vector>
+
+#define DEBUG_TYPE "detailed-records-backend"
+
+#define NL "\n"
+
+using namespace llvm;
+
+namespace {
+
+class DetailedRecordsEmitter {
+private:
+  RecordKeeper &Records;
+
+public:
+  DetailedRecordsEmitter(RecordKeeper &RK) : Records(RK) {}
+
+  void run(raw_ostream &OS);
+  void printReportHeading(raw_ostream &OS);
+  void printVariables(raw_ostream &OS);
+  void printClasses(raw_ostream &OS);
+  void printRecords(raw_ostream &OS);
+  void printSectionHeading(std::string Title, int Count, raw_ostream &OS);
+  void printDefms(Record *Rec, raw_ostream &OS);
+  void printTemplateArgs(Record *Rec, raw_ostream &OS);
+  void printSuperclasses(Record *Rec, raw_ostream &OS);
+  void printFields(Record *Rec, raw_ostream &OS);
+}; // emitter class
+
+} // anonymous namespace
+
+// Print the report.
+void DetailedRecordsEmitter::run(raw_ostream &OS) {
+  printReportHeading(OS);
+  printVariables(OS);
+  printClasses(OS);
+  printRecords(OS);
+}
+
+// Print the report heading, including the source file name.
+void DetailedRecordsEmitter::printReportHeading(raw_ostream &OS) {
+  OS << formatv("DETAILED RECORDS for file {0}\n", Records.getInputFilename());
+}
+
+// Print the global variables.
+void DetailedRecordsEmitter::printVariables(raw_ostream &OS) {
+  const auto GlobalList = Records.getGlobals();
+  printSectionHeading("Global Variables", GlobalList.size(), OS);
+
+  OS << NL;
+  for (const auto &Var : GlobalList) {
+    OS << Var.first << " = " << Var.second->getAsString() << NL;
+  }
+}
+
+// Print the classes, including the template arguments, superclasses,
+// and fields.
+void DetailedRecordsEmitter::printClasses(raw_ostream &OS) {
+  const auto &ClassList = Records.getClasses();
+  printSectionHeading("Classes", ClassList.size(), OS);
+
+  for (const auto &ClassPair : ClassList) {
+    auto *const Class = ClassPair.second.get();
+    OS << formatv("\n{0}  |{1}|\n", Class->getNameInitAsString(),
+                  SrcMgr.getFormattedLocationNoOffset(Class->getLoc().front()));
+    printTemplateArgs(Class, OS);
+    printSuperclasses(Class, OS);
+    printFields(Class, OS);
+  }
+}
+
+// Print the records, including the defm sequences, supercasses,
+// and fields.
+void DetailedRecordsEmitter::printRecords(raw_ostream &OS) {
+  const auto &RecordList = Records.getDefs();
+  printSectionHeading("Records", RecordList.size(), OS);
+
+  for (const auto &RecPair : RecordList) {
+    auto *const Rec = RecPair.second.get();
+    OS << formatv("\n{0}  |{1}|\n", Rec->getNameInitAsString(),
+                  SrcMgr.getFormattedLocationNoOffset(Rec->getLoc().front()));
+    printDefms(Rec, OS);
+    printSuperclasses(Rec, OS);
+    printFields(Rec, OS);
+  }
+}
+
+// Print a section heading with the name of the section and
+// the item count.
+void DetailedRecordsEmitter::printSectionHeading(std::string Title, int Count,
+                                                 raw_ostream &OS) {
+  OS << formatv("\n{0} {1} ({2}) {0}\n", "--------------------", Title, Count);
+}
+
+// Print the record's defm source locations, if any. Note that they
+// are stored in the reverse order of their invocation.
+void DetailedRecordsEmitter::printDefms(Record *Rec, raw_ostream &OS) {
+  const auto &LocList = Rec->getLoc();
+  if (LocList.size() < 2)
+    return;
+
+  OS << "  Defm sequence:";
+  for (unsigned I = LocList.size() - 1; I >= 1; --I) {
+    OS << formatv(" |{0}|", SrcMgr.getFormattedLocationNoOffset(LocList[I]));
+  }
+  OS << NL;
+}
+
+// Print the template arguments of a class.
+void DetailedRecordsEmitter::printTemplateArgs(Record *Rec,
+                                               raw_ostream &OS) {
+  ArrayRef<Init *> Args = Rec->getTemplateArgs();
+  if (Args.empty()) {
+    OS << "  Template args: (none)\n";
+    return;
+  }
+
+  OS << "  Template args:\n";
+  for (const Init *ArgName : Args) {
+    const RecordVal *Value = Rec->getValue(ArgName);
+    assert(Value && "Template argument value not found.");
+    OS << "    ";
+    Value->print(OS, false);
+    OS << formatv("  |{0}|", SrcMgr.getFormattedLocationNoOffset(Value->getLoc()));
+    OS << NL;
+  }
+}
+
+// Print the superclasses of a class or record. Indirect superclasses
+// are enclosed in parentheses.
+void DetailedRecordsEmitter::printSuperclasses(Record *Rec, raw_ostream &OS) {
+  ArrayRef<std::pair<Record *, SMRange>> Superclasses = Rec->getSuperClasses();
+  if (Superclasses.empty()) {
+    OS << "  Superclasses: (none)\n";
+    return;
+  }
+
+  OS << "  Superclasses:";
+  for (const auto &SuperclassPair : Superclasses) {
+    auto *ClassRec = SuperclassPair.first;
+    if (Rec->hasDirectSuperClass(ClassRec))
+      OS << formatv(" {0}", ClassRec->getNameInitAsString());
+    else
+      OS << formatv(" ({0})", ClassRec->getNameInitAsString());
+  }
+  OS << NL;
+}
+
+// Print the fields of a class or record, including their source locations.
+void DetailedRecordsEmitter::printFields(Record *Rec, raw_ostream &OS) {
+  const auto &ValueList = Rec->getValues();
+  if (ValueList.empty()) {
+    OS << "  Fields: (none)\n";
+    return;
+  }
+
+  OS << "  Fields:\n";
+  for (const RecordVal &Value : ValueList)
+    if (!Rec->isTemplateArg(Value.getNameInit())) {
+      OS << "    ";
+      Value.print(OS, false);
+      OS << formatv("  |{0}|\n",
+                    SrcMgr.getFormattedLocationNoOffset(Value.getLoc()));
+    }
+}
+
+namespace llvm {
+
+// This function is called by TableGen after parsing the files.
+
+void EmitDetailedRecords(RecordKeeper &RK, raw_ostream &OS) {
+  // Instantiate the emitter class and invoke run().
+  DetailedRecordsEmitter(RK).run(OS);
+}
+
+} // namespace llvm
diff --git a/llvm/lib/TableGen/Error.cpp b/llvm/lib/TableGen/Error.cpp
index 54b063cb4f8d..eed4de67942a 100644
--- a/llvm/lib/TableGen/Error.cpp
+++ b/llvm/lib/TableGen/Error.cpp
@@ -11,11 +11,12 @@
 //
 //===----------------------------------------------------------------------===//
 
-#include "llvm/TableGen/Error.h"
 #include "llvm/ADT/Twine.h"
+#include "llvm/Support/raw_ostream.h"
 #include "llvm/Support/Signals.h"
 #include "llvm/Support/WithColor.h"
-#include "llvm/Support/raw_ostream.h"
+#include "llvm/TableGen/Error.h"
+#include "llvm/TableGen/Record.h"
 #include <cstdlib>
 
 namespace llvm {
@@ -39,12 +40,54 @@ static void PrintMessage(ArrayRef<SMLoc> Loc, SourceMgr::DiagKind Kind,
                         "instantiated from multiclass");
 }
 
-void PrintNote(const Twine &Msg) { WithColor::note() << Msg << "\n"; }
+// Functions to print notes.
+
+void PrintNote(const Twine &Msg) {
+  WithColor::note() << Msg << "\n";
+}
 
 void PrintNote(ArrayRef<SMLoc> NoteLoc, const Twine &Msg) {
   PrintMessage(NoteLoc, SourceMgr::DK_Note, Msg);
 }
 
+// Functions to print fatal notes.
+
+void PrintFatalNote(const Twine &Msg) {
+  PrintNote(Msg);
+  // The following call runs the file cleanup handlers.
+  sys::RunInterruptHandlers();
+  std::exit(1);
+}
+
+void PrintFatalNote(ArrayRef<SMLoc> NoteLoc, const Twine &Msg) {
+  PrintNote(NoteLoc, Msg);
+  // The following call runs the file cleanup handlers.
+  sys::RunInterruptHandlers();
+  std::exit(1);
+}
+
+// This method takes a Record and uses the source location
+// stored in it.
+void PrintFatalNote(const Record *Rec, const Twine &Msg) {
+  PrintNote(Rec->getLoc(), Msg);
+  // The following call runs the file cleanup handlers.
+  sys::RunInterruptHandlers();
+  std::exit(1);
+}
+
+// This method takes a RecordVal and uses the source location
+// stored in it.
+void PrintFatalNote(const RecordVal *RecVal, const Twine &Msg) {
+  PrintNote(RecVal->getLoc(), Msg);
+  // The following call runs the file cleanup handlers.
+  sys::RunInterruptHandlers();
+  std::exit(1);
+}
+
+// Functions to print warnings.
+
+void PrintWarning(const Twine &Msg) { WithColor::warning() << Msg << "\n"; }
+
 void PrintWarning(ArrayRef<SMLoc> WarningLoc, const Twine &Msg) {
   PrintMessage(WarningLoc, SourceMgr::DK_Warning, Msg);
 }
@@ -53,7 +96,9 @@ void PrintWarning(const char *Loc, const Twine &Msg) {
   SrcMgr.PrintMessage(SMLoc::getFromPointer(Loc), SourceMgr::DK_Warning, Msg);
 }
 
-void PrintWarning(const Twine &Msg) { WithColor::warning() << Msg << "\n"; }
+// Functions to print errors.
+
+void PrintError(const Twine &Msg) { WithColor::error() << Msg << "\n"; }
 
 void PrintError(ArrayRef<SMLoc> ErrorLoc, const Twine &Msg) {
   PrintMessage(ErrorLoc, SourceMgr::DK_Error, Msg);
@@ -63,7 +108,19 @@ void PrintError(const char *Loc, const Twine &Msg) {
   SrcMgr.PrintMessage(SMLoc::getFromPointer(Loc), SourceMgr::DK_Error, Msg);
 }
 
-void PrintError(const Twine &Msg) { WithColor::error() << Msg << "\n"; }
+// This method takes a Record and uses the source location
+// stored in it.
+void PrintError(const Record *Rec, const Twine &Msg) {
+  PrintMessage(Rec->getLoc(), SourceMgr::DK_Error, Msg);
+}
+
+// This method takes a RecordVal and uses the source location
+// stored in it.
+void PrintError(const RecordVal *RecVal, const Twine &Msg) {
+  PrintMessage(RecVal->getLoc(), SourceMgr::DK_Error, Msg);
+}
+
+// Functions to print fatal errors.
 
 void PrintFatalError(const Twine &Msg) {
   PrintError(Msg);
@@ -79,4 +136,22 @@ void PrintFatalError(ArrayRef<SMLoc> ErrorLoc, const Twine &Msg) {
   std::exit(1);
 }
 
+// This method takes a Record and uses the source location
+// stored in it.
+void PrintFatalError(const Record *Rec, const Twine &Msg) {
+  PrintError(Rec->getLoc(), Msg);
+  // The following call runs the file cleanup handlers.
+  sys::RunInterruptHandlers();
+  std::exit(1);
+}
+
+// This method takes a RecordVal and uses the source location
+// stored in it.
+void PrintFatalError(const RecordVal *RecVal, const Twine &Msg) {
+  PrintError(RecVal->getLoc(), Msg);
+  // The following call runs the file cleanup handlers.
+  sys::RunInterruptHandlers();
+  std::exit(1);
+}
+
 } // end namespace llvm
diff --git a/llvm/lib/TableGen/JSONBackend.cpp b/llvm/lib/TableGen/JSONBackend.cpp
index 196644cda667..8ddfd9f04524 100644
--- a/llvm/lib/TableGen/JSONBackend.cpp
+++ b/llvm/lib/TableGen/JSONBackend.cpp
@@ -29,7 +29,6 @@ private:
   RecordKeeper &Records;
 
   json::Value translateInit(const Init &I);
-  json::Array listSuperclasses(const Record &R);
 
 public:
   JSONEmitter(RecordKeeper &R);
@@ -59,8 +58,6 @@ json::Value JSONEmitter::translateInit(const Init &I) {
     return Int->getValue();
   } else if (auto *Str = dyn_cast<StringInit>(&I)) {
     return Str->getValue();
-  } else if (auto *Code = dyn_cast<CodeInit>(&I)) {
-    return Code->getValue();
   } else if (auto *List = dyn_cast<ListInit>(&I)) {
     json::Array array;
     for (auto val : *List)
@@ -147,7 +144,7 @@ void JSONEmitter::run(raw_ostream &OS) {
     for (const RecordVal &RV : Def.getValues()) {
       if (!Def.isTemplateArg(RV.getNameInit())) {
         auto Name = RV.getNameInitAsString();
-        if (RV.getPrefix())
+        if (RV.isNonconcreteOK())
           fields.push_back(Name);
         obj[Name] = translateInit(*RV.getValue());
       }
diff --git a/llvm/lib/TableGen/Main.cpp b/llvm/lib/TableGen/Main.cpp
index 77f1b61cf930..0ace5363dd05 100644
--- a/llvm/lib/TableGen/Main.cpp
+++ b/llvm/lib/TableGen/Main.cpp
@@ -52,6 +52,9 @@ MacroNames("D", cl::desc("Name of the macro to be defined"),
 static cl::opt<bool>
 WriteIfChanged("write-if-changed", cl::desc("Only write output if it changed"));
 
+static cl::opt<bool>
+TimePhases("time-phases", cl::desc("Time phases of parser and backend"));
+
 static int reportError(const char *ProgName, Twine Msg) {
   errs() << ProgName << ": " << Msg;
   errs().flush();
@@ -83,13 +86,20 @@ static int createDependencyFile(const TGParser &Parser, const char *argv0) {
 int llvm::TableGenMain(const char *argv0, TableGenMainFn *MainFn) {
   RecordKeeper Records;
 
+  if (TimePhases)
+    Records.startPhaseTiming();
+
   // Parse the input file.
+
+  Records.startTimer("Parse, build records");
   ErrorOr<std::unique_ptr<MemoryBuffer>> FileOrErr =
       MemoryBuffer::getFileOrSTDIN(InputFilename);
   if (std::error_code EC = FileOrErr.getError())
     return reportError(argv0, "Could not open input file '" + InputFilename +
                                   "': " + EC.message() + "\n");
 
+  Records.saveInputFilename(InputFilename);
+
   // Tell SrcMgr about this buffer, which is what TGParser will pick up.
   SrcMgr.AddNewSourceBuffer(std::move(*FileOrErr), SMLoc());
 
@@ -101,11 +111,15 @@ int llvm::TableGenMain(const char *argv0, TableGenMainFn *MainFn) {
 
   if (Parser.ParseFile())
     return 1;
+  Records.stopTimer();
 
   // Write output to memory.
+  Records.startBackendTimer("Backend overall");
   std::string OutString;
   raw_string_ostream Out(OutString);
-  if (MainFn(Out, Records))
+  unsigned status = MainFn(Out, Records);
+  Records.stopBackendTimer();
+  if (status)
     return 1;
 
   // Always write the depfile, even if the main output hasn't changed.
@@ -117,26 +131,31 @@ int llvm::TableGenMain(const char *argv0, TableGenMainFn *MainFn) {
       return Ret;
   }
 
+  Records.startTimer("Write output");
+  bool WriteFile = true;
   if (WriteIfChanged) {
     // Only updates the real output file if there are any differences.
     // This prevents recompilation of all the files depending on it if there
     // aren't any.
     if (auto ExistingOrErr = MemoryBuffer::getFile(OutputFilename))
       if (std::move(ExistingOrErr.get())->getBuffer() == Out.str())
-        return 0;
+        WriteFile = false;
   }
-
-  std::error_code EC;
-  ToolOutputFile OutFile(OutputFilename, EC, sys::fs::OF_None);
-  if (EC)
-    return reportError(argv0, "error opening " + OutputFilename + ":" +
-                                  EC.message() + "\n");
-  OutFile.os() << Out.str();
+  if (WriteFile) {
+    std::error_code EC;
+    ToolOutputFile OutFile(OutputFilename, EC, sys::fs::OF_None);
+    if (EC)
+      return reportError(argv0, "error opening " + OutputFilename + ": " +
+                                    EC.message() + "\n");
+    OutFile.os() << Out.str();
+    if (ErrorsPrinted == 0)
+      OutFile.keep();
+  }
+  
+  Records.stopTimer();
+  Records.stopPhaseTiming();
 
   if (ErrorsPrinted > 0)
     return reportError(argv0, Twine(ErrorsPrinted) + " errors.\n");
-
-  // Declare success.
-  OutFile.keep();
   return 0;
 }
diff --git a/llvm/lib/TableGen/Record.cpp b/llvm/lib/TableGen/Record.cpp
index d3db004196b8..b6c6b8f031d3 100644
--- a/llvm/lib/TableGen/Record.cpp
+++ b/llvm/lib/TableGen/Record.cpp
@@ -43,15 +43,11 @@ using namespace llvm;
 
 static BumpPtrAllocator Allocator;
 
-STATISTIC(CodeInitsConstructed,
-          "The total number of unique CodeInits constructed");
-
 //===----------------------------------------------------------------------===//
 //    Type implementations
 //===----------------------------------------------------------------------===//
 
 BitRecTy BitRecTy::Shared;
-CodeRecTy CodeRecTy::Shared;
 IntRecTy IntRecTy::Shared;
 StringRecTy StringRecTy::Shared;
 DagRecTy DagRecTy::Shared;
@@ -113,27 +109,22 @@ bool IntRecTy::typeIsConvertibleTo(const RecTy *RHS) const {
   return kind==BitRecTyKind || kind==BitsRecTyKind || kind==IntRecTyKind;
 }
 
-bool CodeRecTy::typeIsConvertibleTo(const RecTy *RHS) const {
-  RecTyKind Kind = RHS->getRecTyKind();
-  return Kind == CodeRecTyKind || Kind == StringRecTyKind;
-}
-
 std::string StringRecTy::getAsString() const {
   return "string";
 }
 
 bool StringRecTy::typeIsConvertibleTo(const RecTy *RHS) const {
   RecTyKind Kind = RHS->getRecTyKind();
-  return Kind == StringRecTyKind || Kind == CodeRecTyKind;
+  return Kind == StringRecTyKind;
 }
 
 std::string ListRecTy::getAsString() const {
-  return "list<" + Ty->getAsString() + ">";
+  return "list<" + ElementTy->getAsString() + ">";
 }
 
 bool ListRecTy::typeIsConvertibleTo(const RecTy *RHS) const {
   if (const auto *ListTy = dyn_cast<ListRecTy>(RHS))
-    return Ty->typeIsConvertibleTo(ListTy->getElementType());
+    return ElementTy->typeIsConvertibleTo(ListTy->getElementType());
   return false;
 }
 
@@ -241,13 +232,10 @@ bool RecordRecTy::typeIsA(const RecTy *RHS) const {
 
 static RecordRecTy *resolveRecordTypes(RecordRecTy *T1, RecordRecTy *T2) {
   SmallVector<Record *, 4> CommonSuperClasses;
-  SmallVector<Record *, 4> Stack;
-
-  Stack.insert(Stack.end(), T1->classes_begin(), T1->classes_end());
+  SmallVector<Record *, 4> Stack(T1->classes_begin(), T1->classes_end());
 
   while (!Stack.empty()) {
-    Record *R = Stack.back();
-    Stack.pop_back();
+    Record *R = Stack.pop_back_val();
 
     if (T2->isSubClassOf(R)) {
       CommonSuperClasses.push_back(R);
@@ -514,45 +502,26 @@ IntInit::convertInitializerBitRange(ArrayRef<unsigned> Bits) const {
   return BitsInit::get(NewBits);
 }
 
-CodeInit *CodeInit::get(StringRef V, const SMLoc &Loc) {
-  static StringSet<BumpPtrAllocator &> ThePool(Allocator);
-
-  CodeInitsConstructed++;
-
-  // Unlike StringMap, StringSet doesn't accept empty keys.
-  if (V.empty())
-    return new (Allocator) CodeInit("", Loc);
-
-  // Location tracking prevents us from de-duping CodeInits as we're never
-  // called with the same string and same location twice. However, we can at
-  // least de-dupe the strings for a modest saving.
-  auto &Entry = *ThePool.insert(V).first;
-  return new(Allocator) CodeInit(Entry.getKey(), Loc);
-}
-
-StringInit *StringInit::get(StringRef V) {
-  static StringMap<StringInit*, BumpPtrAllocator &> ThePool(Allocator);
+StringInit *StringInit::get(StringRef V, StringFormat Fmt) {
+  static StringMap<StringInit*, BumpPtrAllocator &> StringPool(Allocator);
+  static StringMap<StringInit*, BumpPtrAllocator &> CodePool(Allocator);
 
-  auto &Entry = *ThePool.insert(std::make_pair(V, nullptr)).first;
-  if (!Entry.second)
-    Entry.second = new(Allocator) StringInit(Entry.getKey());
-  return Entry.second;
+  if (Fmt == SF_String) {
+    auto &Entry = *StringPool.insert(std::make_pair(V, nullptr)).first;
+    if (!Entry.second)
+      Entry.second = new (Allocator) StringInit(Entry.getKey(), Fmt);
+    return Entry.second;
+  } else {
+    auto &Entry = *CodePool.insert(std::make_pair(V, nullptr)).first;
+    if (!Entry.second)
+      Entry.second = new (Allocator) StringInit(Entry.getKey(), Fmt);
+    return Entry.second;
+  }
 }
 
 Init *StringInit::convertInitializerTo(RecTy *Ty) const {
   if (isa<StringRecTy>(Ty))
     return const_cast<StringInit *>(this);
-  if (isa<CodeRecTy>(Ty))
-    return CodeInit::get(getValue(), SMLoc());
-
-  return nullptr;
-}
-
-Init *CodeInit::convertInitializerTo(RecTy *Ty) const {
-  if (isa<CodeRecTy>(Ty))
-    return const_cast<CodeInit *>(this);
-  if (isa<StringRecTy>(Ty))
-    return StringInit::get(getValue());
 
   return nullptr;
 }
@@ -719,8 +688,10 @@ Init *UnOpInit::Fold(Record *CurRec, bool IsFinal) const {
       if (DefInit *LHSd = dyn_cast<DefInit>(LHS))
         return StringInit::get(LHSd->getAsString());
 
-      if (IntInit *LHSi = dyn_cast<IntInit>(LHS))
+      if (IntInit *LHSi =
+              dyn_cast_or_null<IntInit>(LHS->convertInitializerTo(IntRecTy::get())))
         return StringInit::get(LHSi->getAsString());
+
     } else if (isa<RecordRecTy>(getType())) {
       if (StringInit *Name = dyn_cast<StringInit>(LHS)) {
         if (!CurRec && !IsFinal)
@@ -761,6 +732,12 @@ Init *UnOpInit::Fold(Record *CurRec, bool IsFinal) const {
       return NewInit;
     break;
 
+  case NOT:
+    if (IntInit *LHSi =
+            dyn_cast_or_null<IntInit>(LHS->convertInitializerTo(IntRecTy::get())))
+      return IntInit::get(LHSi->getValue() ? 0 : 1);
+    break;
+
   case HEAD:
     if (ListInit *LHSl = dyn_cast<ListInit>(LHS)) {
       assert(!LHSl->empty() && "Empty list in head");
@@ -780,16 +757,22 @@ Init *UnOpInit::Fold(Record *CurRec, bool IsFinal) const {
   case SIZE:
     if (ListInit *LHSl = dyn_cast<ListInit>(LHS))
       return IntInit::get(LHSl->size());
+    if (DagInit *LHSd = dyn_cast<DagInit>(LHS))
+      return IntInit::get(LHSd->arg_size());
+    if (StringInit *LHSs = dyn_cast<StringInit>(LHS))
+      return IntInit::get(LHSs->getValue().size());
     break;
 
   case EMPTY:
     if (ListInit *LHSl = dyn_cast<ListInit>(LHS))
       return IntInit::get(LHSl->empty());
+    if (DagInit *LHSd = dyn_cast<DagInit>(LHS))
+      return IntInit::get(LHSd->arg_empty());
     if (StringInit *LHSs = dyn_cast<StringInit>(LHS))
       return IntInit::get(LHSs->getValue().empty());
     break;
 
-  case GETOP:
+  case GETDAGOP:
     if (DagInit *Dag = dyn_cast<DagInit>(LHS)) {
       DefInit *DI = DefInit::get(Dag->getOperatorAsDef({}));
       if (!DI->getType()->typeIsA(getType())) {
@@ -820,11 +803,12 @@ std::string UnOpInit::getAsString() const {
   std::string Result;
   switch (getOpcode()) {
   case CAST: Result = "!cast<" + getType()->getAsString() + ">"; break;
+  case NOT: Result = "!not"; break;
   case HEAD: Result = "!head"; break;
   case TAIL: Result = "!tail"; break;
   case SIZE: Result = "!size"; break;
   case EMPTY: Result = "!empty"; break;
-  case GETOP: Result = "!getop"; break;
+  case GETDAGOP: Result = "!getdagop"; break;
   }
   return Result + "(" + LHS->getAsString() + ")";
 }
@@ -862,7 +846,53 @@ static StringInit *ConcatStringInits(const StringInit *I0,
                                      const StringInit *I1) {
   SmallString<80> Concat(I0->getValue());
   Concat.append(I1->getValue());
-  return StringInit::get(Concat);
+  return StringInit::get(Concat, 
+                         StringInit::determineFormat(I0->getFormat(),
+                                                     I1->getFormat()));
+}
+
+static StringInit *interleaveStringList(const ListInit *List,
+                                        const StringInit *Delim) {
+  if (List->size() == 0)
+    return StringInit::get("");
+  StringInit *Element = dyn_cast<StringInit>(List->getElement(0));
+  if (!Element)
+    return nullptr;
+  SmallString<80> Result(Element->getValue());
+  StringInit::StringFormat Fmt = StringInit::SF_String;
+
+  for (unsigned I = 1, E = List->size(); I < E; ++I) {
+    Result.append(Delim->getValue());
+    StringInit *Element = dyn_cast<StringInit>(List->getElement(I));
+    if (!Element)
+      return nullptr;
+    Result.append(Element->getValue());
+    Fmt = StringInit::determineFormat(Fmt, Element->getFormat());
+  }
+  return StringInit::get(Result, Fmt);
+}
+
+static StringInit *interleaveIntList(const ListInit *List,
+                                     const StringInit *Delim) {
+  if (List->size() == 0)
+    return StringInit::get("");
+  IntInit *Element =
+      dyn_cast_or_null<IntInit>(List->getElement(0)
+                                    ->convertInitializerTo(IntRecTy::get()));
+  if (!Element)
+    return nullptr;
+  SmallString<80> Result(Element->getAsString());
+
+  for (unsigned I = 1, E = List->size(); I < E; ++I) {
+    Result.append(Delim->getValue());
+    IntInit *Element =
+        dyn_cast_or_null<IntInit>(List->getElement(I)
+                                      ->convertInitializerTo(IntRecTy::get()));
+    if (!Element)
+      return nullptr;
+    Result.append(Element->getAsString());
+  }
+  return StringInit::get(Result);
 }
 
 Init *BinOpInit::getStrConcat(Init *I0, Init *I1) {
@@ -876,8 +906,8 @@ Init *BinOpInit::getStrConcat(Init *I0, Init *I1) {
 static ListInit *ConcatListInits(const ListInit *LHS,
                                  const ListInit *RHS) {
   SmallVector<Init *, 8> Args;
-  Args.insert(Args.end(), LHS->begin(), LHS->end());
-  Args.insert(Args.end(), RHS->begin(), RHS->end());
+  llvm::append_range(Args, *LHS);
+  llvm::append_range(Args, *RHS);
   return ListInit::get(Args, LHS->getElementType());
 }
 
@@ -891,10 +921,6 @@ Init *BinOpInit::getListConcat(TypedInit *LHS, Init *RHS) {
    return BinOpInit::get(BinOpInit::LISTCONCAT, LHS, RHS, LHS->getType());
 }
 
-Init *BinOpInit::getListSplat(TypedInit *LHS, Init *RHS) {
-  return BinOpInit::get(BinOpInit::LISTSPLAT, LHS, RHS, LHS->getType());
-}
-
 Init *BinOpInit::Fold(Record *CurRec) const {
   switch (getOpcode()) {
   case CONCAT: {
@@ -934,8 +960,8 @@ Init *BinOpInit::Fold(Record *CurRec) const {
     ListInit *RHSs = dyn_cast<ListInit>(RHS);
     if (LHSs && RHSs) {
       SmallVector<Init *, 8> Args;
-      Args.insert(Args.end(), LHSs->begin(), LHSs->end());
-      Args.insert(Args.end(), RHSs->begin(), RHSs->end());
+      llvm::append_range(Args, *LHSs);
+      llvm::append_range(Args, *RHSs);
       return ListInit::get(Args, LHSs->getElementType());
     }
     break;
@@ -956,47 +982,76 @@ Init *BinOpInit::Fold(Record *CurRec) const {
       return ConcatStringInits(LHSs, RHSs);
     break;
   }
+  case INTERLEAVE: {
+    ListInit *List = dyn_cast<ListInit>(LHS);
+    StringInit *Delim = dyn_cast<StringInit>(RHS);
+    if (List && Delim) {
+      StringInit *Result;
+      if (isa<StringRecTy>(List->getElementType()))
+        Result = interleaveStringList(List, Delim);
+      else
+        Result = interleaveIntList(List, Delim);
+      if (Result)
+        return Result;
+    }
+    break;
+  }
   case EQ:
   case NE:
   case LE:
   case LT:
   case GE:
   case GT: {
-    // try to fold eq comparison for 'bit' and 'int', otherwise fallback
-    // to string objects.
-    IntInit *L =
+    // First see if we have two bit, bits, or int.
+    IntInit *LHSi =
         dyn_cast_or_null<IntInit>(LHS->convertInitializerTo(IntRecTy::get()));
-    IntInit *R =
+    IntInit *RHSi =
         dyn_cast_or_null<IntInit>(RHS->convertInitializerTo(IntRecTy::get()));
 
-    if (L && R) {
+    if (LHSi && RHSi) {
       bool Result;
       switch (getOpcode()) {
-      case EQ: Result = L->getValue() == R->getValue(); break;
-      case NE: Result = L->getValue() != R->getValue(); break;
-      case LE: Result = L->getValue() <= R->getValue(); break;
-      case LT: Result = L->getValue() < R->getValue(); break;
-      case GE: Result = L->getValue() >= R->getValue(); break;
-      case GT: Result = L->getValue() > R->getValue(); break;
+      case EQ: Result = LHSi->getValue() == RHSi->getValue(); break;
+      case NE: Result = LHSi->getValue() != RHSi->getValue(); break;
+      case LE: Result = LHSi->getValue() <= RHSi->getValue(); break;
+      case LT: Result = LHSi->getValue() <  RHSi->getValue(); break;
+      case GE: Result = LHSi->getValue() >= RHSi->getValue(); break;
+      case GT: Result = LHSi->getValue() >  RHSi->getValue(); break;
       default: llvm_unreachable("unhandled comparison");
       }
       return BitInit::get(Result);
     }
 
-    if (getOpcode() == EQ || getOpcode() == NE) {
-      StringInit *LHSs = dyn_cast<StringInit>(LHS);
-      StringInit *RHSs = dyn_cast<StringInit>(RHS);
+    // Next try strings.
+    StringInit *LHSs = dyn_cast<StringInit>(LHS);
+    StringInit *RHSs = dyn_cast<StringInit>(RHS);
 
-      // Make sure we've resolved
-      if (LHSs && RHSs) {
-        bool Equal = LHSs->getValue() == RHSs->getValue();
-        return BitInit::get(getOpcode() == EQ ? Equal : !Equal);
+    if (LHSs && RHSs) {
+      bool Result;
+      switch (getOpcode()) {
+      case EQ: Result = LHSs->getValue() == RHSs->getValue(); break;
+      case NE: Result = LHSs->getValue() != RHSs->getValue(); break;
+      case LE: Result = LHSs->getValue() <= RHSs->getValue(); break;
+      case LT: Result = LHSs->getValue() <  RHSs->getValue(); break;
+      case GE: Result = LHSs->getValue() >= RHSs->getValue(); break;
+      case GT: Result = LHSs->getValue() >  RHSs->getValue(); break;
+      default: llvm_unreachable("unhandled comparison");
       }
+      return BitInit::get(Result);
+    }
+
+    // Finally, !eq and !ne can be used with records.
+    if (getOpcode() == EQ || getOpcode() == NE) {
+      DefInit *LHSd = dyn_cast<DefInit>(LHS);
+      DefInit *RHSd = dyn_cast<DefInit>(RHS);
+      if (LHSd && RHSd)
+        return BitInit::get((getOpcode() == EQ) ? LHSd == RHSd
+                                                : LHSd != RHSd);
     }
 
     break;
   }
-  case SETOP: {
+  case SETDAGOP: {
     DagInit *Dag = dyn_cast<DagInit>(LHS);
     DefInit *Op = dyn_cast<DefInit>(RHS);
     if (Dag && Op) {
@@ -1011,9 +1066,11 @@ Init *BinOpInit::Fold(Record *CurRec) const {
     break;
   }
   case ADD:
+  case SUB:
   case MUL:
   case AND:
   case OR:
+  case XOR:
   case SHL:
   case SRA:
   case SRL: {
@@ -1026,10 +1083,12 @@ Init *BinOpInit::Fold(Record *CurRec) const {
       int64_t Result;
       switch (getOpcode()) {
       default: llvm_unreachable("Bad opcode!");
-      case ADD: Result = LHSv +  RHSv; break;
-      case MUL: Result = LHSv *  RHSv; break;
-      case AND: Result = LHSv &  RHSv; break;
-      case OR: Result = LHSv | RHSv; break;
+      case ADD: Result = LHSv + RHSv; break;
+      case SUB: Result = LHSv - RHSv; break;
+      case MUL: Result = LHSv * RHSv; break;
+      case AND: Result = LHSv & RHSv; break;
+      case OR:  Result = LHSv | RHSv; break;
+      case XOR: Result = LHSv ^ RHSv; break;
       case SHL: Result = (uint64_t)LHSv << (uint64_t)RHSv; break;
       case SRA: Result = LHSv >> RHSv; break;
       case SRL: Result = (uint64_t)LHSv >> (uint64_t)RHSv; break;
@@ -1057,9 +1116,11 @@ std::string BinOpInit::getAsString() const {
   switch (getOpcode()) {
   case CONCAT: Result = "!con"; break;
   case ADD: Result = "!add"; break;
+  case SUB: Result = "!sub"; break;
   case MUL: Result = "!mul"; break;
   case AND: Result = "!and"; break;
   case OR: Result = "!or"; break;
+  case XOR: Result = "!xor"; break;
   case SHL: Result = "!shl"; break;
   case SRA: Result = "!sra"; break;
   case SRL: Result = "!srl"; break;
@@ -1072,7 +1133,8 @@ std::string BinOpInit::getAsString() const {
   case LISTCONCAT: Result = "!listconcat"; break;
   case LISTSPLAT: Result = "!listsplat"; break;
   case STRCONCAT: Result = "!strconcat"; break;
-  case SETOP: Result = "!setop"; break;
+  case INTERLEAVE: Result = "!interleave"; break;
+  case SETDAGOP: Result = "!setdagop"; break;
   }
   return Result + "(" + LHS->getAsString() + ", " + RHS->getAsString() + ")";
 }
@@ -1107,7 +1169,7 @@ void TernOpInit::Profile(FoldingSetNodeID &ID) const {
   ProfileTernOpInit(ID, getOpcode(), getLHS(), getMHS(), getRHS(), getType());
 }
 
-static Init *ForeachApply(Init *LHS, Init *MHSe, Init *RHS, Record *CurRec) {
+static Init *ItemApply(Init *LHS, Init *MHSe, Init *RHS, Record *CurRec) {
   MapResolver R(CurRec);
   R.set(LHS, MHSe);
   return RHS->resolveReferences(R);
@@ -1116,7 +1178,7 @@ static Init *ForeachApply(Init *LHS, Init *MHSe, Init *RHS, Record *CurRec) {
 static Init *ForeachDagApply(Init *LHS, DagInit *MHSd, Init *RHS,
                              Record *CurRec) {
   bool Change = false;
-  Init *Val = ForeachApply(LHS, MHSd->getOperator(), RHS, CurRec);
+  Init *Val = ItemApply(LHS, MHSd->getOperator(), RHS, CurRec);
   if (Val != MHSd->getOperator())
     Change = true;
 
@@ -1129,7 +1191,7 @@ static Init *ForeachDagApply(Init *LHS, DagInit *MHSd, Init *RHS,
     if (DagInit *Argd = dyn_cast<DagInit>(Arg))
       NewArg = ForeachDagApply(LHS, Argd, RHS, CurRec);
     else
-      NewArg = ForeachApply(LHS, Arg, RHS, CurRec);
+      NewArg = ItemApply(LHS, Arg, RHS, CurRec);
 
     NewArgs.push_back(std::make_pair(NewArg, ArgName));
     if (Arg != NewArg)
@@ -1151,7 +1213,7 @@ static Init *ForeachHelper(Init *LHS, Init *MHS, Init *RHS, RecTy *Type,
     SmallVector<Init *, 8> NewList(MHSl->begin(), MHSl->end());
 
     for (Init *&Item : NewList) {
-      Init *NewItem = ForeachApply(LHS, Item, RHS, CurRec);
+      Init *NewItem = ItemApply(LHS, Item, RHS, CurRec);
       if (NewItem != Item)
         Item = NewItem;
     }
@@ -1161,6 +1223,31 @@ static Init *ForeachHelper(Init *LHS, Init *MHS, Init *RHS, RecTy *Type,
   return nullptr;
 }
 
+// Evaluates RHS for all elements of MHS, using LHS as a temp variable.
+// Creates a new list with the elements that evaluated to true.
+static Init *FilterHelper(Init *LHS, Init *MHS, Init *RHS, RecTy *Type,
+                          Record *CurRec) {
+  if (ListInit *MHSl = dyn_cast<ListInit>(MHS)) {
+    SmallVector<Init *, 8> NewList;
+
+    for (Init *Item : MHSl->getValues()) {
+      Init *Include = ItemApply(LHS, Item, RHS, CurRec);
+      if (!Include)
+        return nullptr;
+      if (IntInit *IncludeInt = dyn_cast_or_null<IntInit>(
+                                    Include->convertInitializerTo(IntRecTy::get()))) {
+        if (IncludeInt->getValue())          
+          NewList.push_back(Item);
+      } else {
+        return nullptr;
+      }
+    }
+    return ListInit::get(NewList, cast<ListRecTy>(Type)->getElementType());
+  }
+
+  return nullptr;
+}
+
 Init *TernOpInit::Fold(Record *CurRec) const {
   switch (getOpcode()) {
   case SUBST: {
@@ -1213,6 +1300,12 @@ Init *TernOpInit::Fold(Record *CurRec) const {
     break;
   }
 
+  case FILTER: {
+    if (Init *Result = FilterHelper(LHS, MHS, RHS, getType(), CurRec))
+      return Result;
+    break;
+  }
+
   case IF: {
     if (IntInit *LHSi = dyn_cast_or_null<IntInit>(
                             LHS->convertInitializerTo(IntRecTy::get()))) {
@@ -1246,6 +1339,27 @@ Init *TernOpInit::Fold(Record *CurRec) const {
     }
     break;
   }
+
+  case SUBSTR: {
+    StringInit *LHSs = dyn_cast<StringInit>(LHS);
+    IntInit *MHSi = dyn_cast<IntInit>(MHS);
+    IntInit *RHSi = dyn_cast<IntInit>(RHS);
+    if (LHSs && MHSi && RHSi) {
+      int64_t StringSize = LHSs->getValue().size();
+      int64_t Start = MHSi->getValue();
+      int64_t Length = RHSi->getValue();
+      if (Start < 0 || Start > StringSize)
+        PrintError(CurRec->getLoc(),
+                   Twine("!substr start position is out of range 0...") +
+                       std::to_string(StringSize) + ": " +
+                       std::to_string(Start));
+      if (Length < 0)
+        PrintError(CurRec->getLoc(), "!substr length must be nonnegative");
+      return StringInit::get(LHSs->getValue().substr(Start, Length),
+                             LHSs->getFormat());
+    }
+    break;
+  }
   }
 
   return const_cast<TernOpInit *>(this);
@@ -1267,7 +1381,7 @@ Init *TernOpInit::resolveReferences(Resolver &R) const {
   Init *mhs = MHS->resolveReferences(R);
   Init *rhs;
 
-  if (getOpcode() == FOREACH) {
+  if (getOpcode() == FOREACH || getOpcode() == FILTER) {
     ShadowResolver SR(R);
     SR.addShadow(lhs);
     rhs = RHS->resolveReferences(SR);
@@ -1285,10 +1399,12 @@ std::string TernOpInit::getAsString() const {
   std::string Result;
   bool UnquotedLHS = false;
   switch (getOpcode()) {
-  case SUBST: Result = "!subst"; break;
+  case DAG: Result = "!dag"; break;
+  case FILTER: Result = "!filter"; UnquotedLHS = true; break;
   case FOREACH: Result = "!foreach"; UnquotedLHS = true; break;
   case IF: Result = "!if"; break;
-  case DAG: Result = "!dag"; break;
+  case SUBST: Result = "!subst"; break;
+  case SUBSTR: Result = "!substr"; break;
   }
   return (Result + "(" +
           (UnquotedLHS ? LHS->getAsUnquotedString() : LHS->getAsString()) +
@@ -2026,8 +2142,16 @@ std::string DagInit::getAsString() const {
 //    Other implementations
 //===----------------------------------------------------------------------===//
 
-RecordVal::RecordVal(Init *N, RecTy *T, bool P)
-  : Name(N), TyAndPrefix(T, P) {
+RecordVal::RecordVal(Init *N, RecTy *T, FieldKind K)
+    : Name(N), TyAndKind(T, K) {
+  setValue(UnsetInit::get());
+  assert(Value && "Cannot create unset value for current type!");
+}
+
+// This constructor accepts the same arguments as the above, but also
+// a source location.
+RecordVal::RecordVal(Init *N, SMLoc Loc, RecTy *T, FieldKind K)
+    : Name(N), Loc(Loc), TyAndKind(T, K) {
   setValue(UnsetInit::get());
   assert(Value && "Cannot create unset value for current type!");
 }
@@ -2036,6 +2160,21 @@ StringRef RecordVal::getName() const {
   return cast<StringInit>(getNameInit())->getValue();
 }
 
+std::string RecordVal::getPrintType() const {
+  if (getType() == StringRecTy::get()) {
+    if (auto *StrInit = dyn_cast<StringInit>(Value)) {
+      if (StrInit->hasCodeFormat())
+        return "code";
+      else
+        return "string";
+    } else {
+      return "string";
+    }
+  } else {
+    return TyAndKind.getPointer()->getAsString();
+  }
+}
+
 bool RecordVal::setValue(Init *V) {
   if (V) {
     Value = V->getCastTo(getType());
@@ -2046,8 +2185,33 @@ bool RecordVal::setValue(Init *V) {
         if (!isa<BitsInit>(Value)) {
           SmallVector<Init *, 64> Bits;
           Bits.reserve(BTy->getNumBits());
-          for (unsigned i = 0, e = BTy->getNumBits(); i < e; ++i)
-            Bits.push_back(Value->getBit(i));
+          for (unsigned I = 0, E = BTy->getNumBits(); I < E; ++I)
+            Bits.push_back(Value->getBit(I));
+          Value = BitsInit::get(Bits);
+        }
+      }
+    }
+    return Value == nullptr;
+  }
+  Value = nullptr;
+  return false;
+}
+
+// This version of setValue takes a source location and resets the
+// location in the RecordVal.
+bool RecordVal::setValue(Init *V, SMLoc NewLoc) {
+  Loc = NewLoc;
+  if (V) {
+    Value = V->getCastTo(getType());
+    if (Value) {
+      assert(!isa<TypedInit>(Value) ||
+             cast<TypedInit>(Value)->getType()->typeIsA(getType()));
+      if (BitsRecTy *BTy = dyn_cast<BitsRecTy>(getType())) {
+        if (!isa<BitsInit>(Value)) {
+          SmallVector<Init *, 64> Bits;
+          Bits.reserve(BTy->getNumBits());
+          for (unsigned I = 0, E = BTy->getNumBits(); I < E; ++I)
+            Bits.push_back(Value->getBit(I));
           Value = BitsInit::get(Bits);
         }
       }
@@ -2058,13 +2222,14 @@ bool RecordVal::setValue(Init *V) {
   return false;
 }
 
+#include "llvm/TableGen/Record.h"
 #if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
 LLVM_DUMP_METHOD void RecordVal::dump() const { errs() << *this; }
 #endif
 
 void RecordVal::print(raw_ostream &OS, bool PrintSem) const {
-  if (getPrefix()) OS << "field ";
-  OS << *getType() << " " << getNameInitAsString();
+  if (isNonconcreteOK()) OS << "field ";
+  OS << getPrintType() << " " << getNameInitAsString();
 
   if (getValue())
     OS << " = " << *getValue();
@@ -2089,9 +2254,9 @@ RecordRecTy *Record::getType() {
 }
 
 DefInit *Record::getDefInit() {
-  if (!TheInit)
-    TheInit = new(Allocator) DefInit(this);
-  return TheInit;
+  if (!CorrespondingDefInit)
+    CorrespondingDefInit = new (Allocator) DefInit(this);
+  return CorrespondingDefInit;
 }
 
 void Record::setName(Init *NewName) {
@@ -2110,11 +2275,28 @@ void Record::setName(Init *NewName) {
   // this.  See TGParser::ParseDef and TGParser::ParseDefm.
 }
 
+// NOTE for the next two functions:
+// Superclasses are in post-order, so the final one is a direct
+// superclass. All of its transitive superclases immediately precede it,
+// so we can step through the direct superclasses in reverse order.
+
+bool Record::hasDirectSuperClass(const Record *Superclass) const {
+  ArrayRef<std::pair<Record *, SMRange>> SCs = getSuperClasses();
+
+  for (int I = SCs.size() - 1; I >= 0; --I) {
+    const Record *SC = SCs[I].first;
+    if (SC == Superclass)
+      return true;
+    I -= SC->getSuperClasses().size();
+  }
+
+  return false;
+}
+
 void Record::getDirectSuperClasses(SmallVectorImpl<Record *> &Classes) const {
   ArrayRef<std::pair<Record *, SMRange>> SCs = getSuperClasses();
+
   while (!SCs.empty()) {
-    // Superclasses are in reverse preorder, so 'back' is a direct superclass,
-    // and its transitive superclasses are directly preceding it.
     Record *SC = SCs.back().first;
     SCs = SCs.drop_back(1 + SC->getSuperClasses().size());
     Classes.push_back(SC);
@@ -2187,15 +2369,23 @@ raw_ostream &llvm::operator<<(raw_ostream &OS, const Record &R) {
   OS << "\n";
 
   for (const RecordVal &Val : R.getValues())
-    if (Val.getPrefix() && !R.isTemplateArg(Val.getNameInit()))
+    if (Val.isNonconcreteOK() && !R.isTemplateArg(Val.getNameInit()))
       OS << Val;
   for (const RecordVal &Val : R.getValues())
-    if (!Val.getPrefix() && !R.isTemplateArg(Val.getNameInit()))
+    if (!Val.isNonconcreteOK() && !R.isTemplateArg(Val.getNameInit()))
       OS << Val;
 
   return OS << "}\n";
 }
 
+SMLoc Record::getFieldLoc(StringRef FieldName) const {
+  const RecordVal *R = getValue(FieldName);
+  if (!R)
+    PrintFatalError(getLoc(), "Record `" + getName() +
+      "' does not have a field named `" + FieldName + "'!\n");
+  return R->getLoc();
+}
+
 Init *Record::getValueInit(StringRef FieldName) const {
   const RecordVal *R = getValue(FieldName);
   if (!R || !R->getValue())
@@ -2205,18 +2395,27 @@ Init *Record::getValueInit(StringRef FieldName) const {
 }
 
 StringRef Record::getValueAsString(StringRef FieldName) const {
-  const RecordVal *R = getValue(FieldName);
-  if (!R || !R->getValue())
+  llvm::Optional<StringRef> S = getValueAsOptionalString(FieldName);
+  if (!S.hasValue())
     PrintFatalError(getLoc(), "Record `" + getName() +
       "' does not have a field named `" + FieldName + "'!\n");
+  return S.getValue();
+}
+
+llvm::Optional<StringRef>
+Record::getValueAsOptionalString(StringRef FieldName) const {
+  const RecordVal *R = getValue(FieldName);
+  if (!R || !R->getValue())
+    return llvm::Optional<StringRef>();
+  if (isa<UnsetInit>(R->getValue()))
+    return llvm::Optional<StringRef>();
 
   if (StringInit *SI = dyn_cast<StringInit>(R->getValue()))
     return SI->getValue();
-  if (CodeInit *CI = dyn_cast<CodeInit>(R->getValue()))
-    return CI->getValue();
 
-  PrintFatalError(getLoc(), "Record `" + getName() + "', field `" +
-    FieldName + "' does not have a string initializer!");
+  PrintFatalError(getLoc(),
+                  "Record `" + getName() + "', ` field `" + FieldName +
+                      "' exists but does not have a string initializer!");
 }
 
 BitsInit *Record::getValueAsBitsInit(StringRef FieldName) const {
@@ -2227,8 +2426,8 @@ BitsInit *Record::getValueAsBitsInit(StringRef FieldName) const {
 
   if (BitsInit *BI = dyn_cast<BitsInit>(R->getValue()))
     return BI;
-  PrintFatalError(getLoc(), "Record `" + getName() + "', field `" +
-    FieldName + "' does not have a BitsInit initializer!");
+  PrintFatalError(getLoc(), "Record `" + getName() + "', field `" + FieldName + 
+                                "' exists but does not have a bits value");
 }
 
 ListInit *Record::getValueAsListInit(StringRef FieldName) const {
@@ -2239,8 +2438,8 @@ ListInit *Record::getValueAsListInit(StringRef FieldName) const {
 
   if (ListInit *LI = dyn_cast<ListInit>(R->getValue()))
     return LI;
-  PrintFatalError(getLoc(), "Record `" + getName() + "', field `" +
-    FieldName + "' does not have a list initializer!");
+  PrintFatalError(getLoc(), "Record `" + getName() + "', field `" + FieldName + 
+                                "' exists but does not have a list value");
 }
 
 std::vector<Record*>
@@ -2267,7 +2466,7 @@ int64_t Record::getValueAsInt(StringRef FieldName) const {
     return II->getValue();
   PrintFatalError(getLoc(), Twine("Record `") + getName() + "', field `" +
                                 FieldName +
-                                "' does not have an int initializer: " +
+                                "' exists but does not have an int value: " +
                                 R->getValue()->getAsString());
 }
 
@@ -2281,7 +2480,7 @@ Record::getValueAsListOfInts(StringRef FieldName) const {
     else
       PrintFatalError(getLoc(),
                       Twine("Record `") + getName() + "', field `" + FieldName +
-                          "' does not have a list of ints initializer: " +
+                          "' exists but does not have a list of ints value: " +
                           I->getAsString());
   }
   return Ints;
@@ -2294,12 +2493,10 @@ Record::getValueAsListOfStrings(StringRef FieldName) const {
   for (Init *I : List->getValues()) {
     if (StringInit *SI = dyn_cast<StringInit>(I))
       Strings.push_back(SI->getValue());
-    else if (CodeInit *CI = dyn_cast<CodeInit>(I))
-      Strings.push_back(CI->getValue());
     else
       PrintFatalError(getLoc(),
                       Twine("Record `") + getName() + "', field `" + FieldName +
-                          "' does not have a list of strings initializer: " +
+                          "' exists but does not have a list of strings value: " +
                           I->getAsString());
   }
   return Strings;
@@ -2394,16 +2591,78 @@ Init *RecordKeeper::getNewAnonymousName() {
   return StringInit::get("anonymous_" + utostr(AnonCounter++));
 }
 
-std::vector<Record *>
-RecordKeeper::getAllDerivedDefinitions(StringRef ClassName) const {
-  Record *Class = getClass(ClassName);
-  if (!Class)
-    PrintFatalError("ERROR: Couldn't find the `" + ClassName + "' class!\n");
+// These functions implement the phase timing facility. Starting a timer
+// when one is already running stops the running one.
 
-  std::vector<Record*> Defs;
-  for (const auto &D : getDefs())
-    if (D.second->isSubClassOf(Class))
-      Defs.push_back(D.second.get());
+void RecordKeeper::startTimer(StringRef Name) {
+  if (TimingGroup) {
+    if (LastTimer && LastTimer->isRunning()) {
+      LastTimer->stopTimer();
+      if (BackendTimer) {
+        LastTimer->clear();
+        BackendTimer = false;
+      }
+    }
+
+    LastTimer = new Timer("", Name, *TimingGroup);
+    LastTimer->startTimer();
+  }
+}
+
+void RecordKeeper::stopTimer() {
+  if (TimingGroup) {
+    assert(LastTimer && "No phase timer was started");
+    LastTimer->stopTimer();
+  }
+}
+
+void RecordKeeper::startBackendTimer(StringRef Name) {
+  if (TimingGroup) {
+    startTimer(Name);
+    BackendTimer = true;
+  }
+}
+
+void RecordKeeper::stopBackendTimer() {
+  if (TimingGroup) {
+    if (BackendTimer) {
+      stopTimer();
+      BackendTimer = false;
+    }
+  }
+}
+
+// We cache the record vectors for single classes. Many backends request
+// the same vectors multiple times.
+std::vector<Record *> RecordKeeper::getAllDerivedDefinitions(
+    StringRef ClassName) const {
+
+  auto Pair = ClassRecordsMap.try_emplace(ClassName);
+  if (Pair.second)
+    Pair.first->second = getAllDerivedDefinitions(makeArrayRef(ClassName));
+
+  return Pair.first->second;
+}
+
+std::vector<Record *> RecordKeeper::getAllDerivedDefinitions(
+    ArrayRef<StringRef> ClassNames) const {
+  SmallVector<Record *, 2> ClassRecs;
+  std::vector<Record *> Defs;
+
+  assert(ClassNames.size() > 0 && "At least one class must be passed.");
+  for (const auto &ClassName : ClassNames) {
+    Record *Class = getClass(ClassName);
+    if (!Class)
+      PrintFatalError("The class '" + ClassName + "' is not defined\n");
+    ClassRecs.push_back(Class);
+  }
+
+  for (const auto &OneDef : getDefs()) {
+    if (all_of(ClassRecs, [&OneDef](const Record *Class) {
+                            return OneDef.second->isSubClassOf(Class);
+                          }))
+      Defs.push_back(OneDef.second.get());
+  }
 
   return Defs;
 }
diff --git a/llvm/lib/TableGen/TGLexer.cpp b/llvm/lib/TableGen/TGLexer.cpp
index 9e6cc947925d..94c79102c7cd 100644
--- a/llvm/lib/TableGen/TGLexer.cpp
+++ b/llvm/lib/TableGen/TGLexer.cpp
@@ -150,7 +150,7 @@ tgtok::TokKind TGLexer::LexToken(bool FileOrLineStart) {
   case EOF:
     // Lex next token, if we just left an include file.
     // Note that leaving an include file means that the next
-    // symbol is located at the end of 'include "..."'
+    // symbol is located at the end of the 'include "..."'
     // construct, so LexToken() is called with default
     // false parameter.
     if (processEOF())
@@ -161,7 +161,6 @@ tgtok::TokKind TGLexer::LexToken(bool FileOrLineStart) {
 
   case ':': return tgtok::colon;
   case ';': return tgtok::semi;
-  case '.': return tgtok::period;
   case ',': return tgtok::comma;
   case '<': return tgtok::less;
   case '>': return tgtok::greater;
@@ -181,6 +180,19 @@ tgtok::TokKind TGLexer::LexToken(bool FileOrLineStart) {
 
     return tgtok::paste;
 
+  // The period is a separate case so we can recognize the "..."
+  // range punctuator.
+  case '.':
+    if (peekNextChar(0) == '.') {
+      ++CurPtr; // Eat second dot.
+      if (peekNextChar(0) == '.') {
+        ++CurPtr; // Eat third dot.
+        return tgtok::dotdotdot;
+      }
+      return ReturnError(TokStart, "Invalid '..' punctuation");
+    }
+    return tgtok::dot;
+
   case '\r':
     PrintFatalError("getNextChar() must never return '\r'");
     return tgtok::Error;
@@ -326,14 +338,9 @@ tgtok::TokKind TGLexer::LexIdentifier() {
   while (isalpha(*CurPtr) || isdigit(*CurPtr) || *CurPtr == '_')
     ++CurPtr;
 
-  // Check to see if this identifier is a keyword.
+  // Check to see if this identifier is a reserved keyword.
   StringRef Str(IdentStart, CurPtr-IdentStart);
 
-  if (Str == "include") {
-    if (LexInclude()) return tgtok::Error;
-    return Lex();
-  }
-
   tgtok::TokKind Kind = StringSwitch<tgtok::TokKind>(Str)
     .Case("int", tgtok::Int)
     .Case("bit", tgtok::Bit)
@@ -344,6 +351,8 @@ tgtok::TokKind TGLexer::LexIdentifier() {
     .Case("dag", tgtok::Dag)
     .Case("class", tgtok::Class)
     .Case("def", tgtok::Def)
+    .Case("true", tgtok::TrueVal)
+    .Case("false", tgtok::FalseVal)
     .Case("foreach", tgtok::Foreach)
     .Case("defm", tgtok::Defm)
     .Case("defset", tgtok::Defset)
@@ -352,13 +361,25 @@ tgtok::TokKind TGLexer::LexIdentifier() {
     .Case("let", tgtok::Let)
     .Case("in", tgtok::In)
     .Case("defvar", tgtok::Defvar)
+    .Case("include", tgtok::Include)
     .Case("if", tgtok::If)
     .Case("then", tgtok::Then)
     .Case("else", tgtok::ElseKW)
+    .Case("assert", tgtok::Assert)
     .Default(tgtok::Id);
 
-  if (Kind == tgtok::Id)
-    CurStrVal.assign(Str.begin(), Str.end());
+  // A couple of tokens require special processing.
+  switch (Kind) {
+    case tgtok::Include:
+      if (LexInclude()) return tgtok::Error;
+      return Lex();
+    case tgtok::Id:
+      CurStrVal.assign(Str.begin(), Str.end());
+      break;
+    default:
+      break;
+  }
+
   return Kind;
 }
 
@@ -520,7 +541,7 @@ tgtok::TokKind TGLexer::LexBracket() {
     }
   }
 
-  return ReturnError(CodeStart-2, "Unterminated Code Block");
+  return ReturnError(CodeStart - 2, "Unterminated code block");
 }
 
 /// LexExclaim - Lex '!' and '![a-zA-Z]+'.
@@ -550,9 +571,12 @@ tgtok::TokKind TGLexer::LexExclaim() {
     .Case("con", tgtok::XConcat)
     .Case("dag", tgtok::XDag)
     .Case("add", tgtok::XADD)
+    .Case("sub", tgtok::XSUB)
     .Case("mul", tgtok::XMUL)
+    .Case("not", tgtok::XNOT)
     .Case("and", tgtok::XAND)
     .Case("or", tgtok::XOR)
+    .Case("xor", tgtok::XXOR)
     .Case("shl", tgtok::XSHL)
     .Case("sra", tgtok::XSRA)
     .Case("srl", tgtok::XSRL)
@@ -561,11 +585,14 @@ tgtok::TokKind TGLexer::LexExclaim() {
     .Case("subst", tgtok::XSubst)
     .Case("foldl", tgtok::XFoldl)
     .Case("foreach", tgtok::XForEach)
+    .Case("filter", tgtok::XFilter)
     .Case("listconcat", tgtok::XListConcat)
     .Case("listsplat", tgtok::XListSplat)
     .Case("strconcat", tgtok::XStrConcat)
-    .Case("setop", tgtok::XSetOp)
-    .Case("getop", tgtok::XGetOp)
+    .Case("interleave", tgtok::XInterleave)
+    .Case("substr", tgtok::XSubstr)
+    .Cases("setdagop", "setop", tgtok::XSetDagOp) // !setop is deprecated.
+    .Cases("getdagop", "getop", tgtok::XGetDagOp) // !getop is deprecated.
     .Default(tgtok::Error);
 
   return Kind != tgtok::Error ? Kind : ReturnError(Start-1, "Unknown operator");
diff --git a/llvm/lib/TableGen/TGLexer.h b/llvm/lib/TableGen/TGLexer.h
index 5b3b0a44e3ef..2f322f705e0d 100644
--- a/llvm/lib/TableGen/TGLexer.h
+++ b/llvm/lib/TableGen/TGLexer.h
@@ -40,19 +40,25 @@ namespace tgtok {
     l_paren, r_paren,   // ( )
     less, greater,      // < >
     colon, semi,        // : ;
-    comma, period,      // , .
+    comma, dot,         // , .
     equal, question,    // = ?
     paste,              // #
+    dotdotdot,          // ...
 
-    // Keywords. ('ElseKW' is named to distinguish it from the existing 'Else'
-    // that means the preprocessor #else.)
-    Bit, Bits, Class, Code, Dag, Def, Foreach, Defm, Field, In, Int, Let, List,
-    MultiClass, String, Defset, Defvar, If, Then, ElseKW,
+    // Reserved keywords. ('ElseKW' is named to distinguish it from the
+    // existing 'Else' that means the preprocessor #else.)
+    Assert, Bit, Bits, Class, Code, Dag, Def, Defm, Defset, Defvar, ElseKW,
+    FalseKW, Field, Foreach, If, In, Include, Int, Let, List, MultiClass,
+    String, Then, TrueKW,
 
-    // !keywords.
-    XConcat, XADD, XMUL, XAND, XOR, XSRA, XSRL, XSHL, XListConcat, XListSplat,
-    XStrConcat, XCast, XSubst, XForEach, XFoldl, XHead, XTail, XSize, XEmpty,
-    XIf, XCond, XEq, XIsA, XDag, XNe, XLe, XLt, XGe, XGt, XSetOp, XGetOp,
+    // Bang operators.
+    XConcat, XADD, XSUB, XMUL, XNOT, XAND, XOR, XXOR, XSRA, XSRL, XSHL,
+    XListConcat, XListSplat, XStrConcat, XInterleave, XSubstr, XCast,
+    XSubst, XForEach, XFilter, XFoldl, XHead, XTail, XSize, XEmpty, XIf,
+    XCond, XEq, XIsA, XDag, XNe, XLe, XLt, XGe, XGt, XSetDagOp, XGetDagOp,
+
+    // Boolean literals.
+    TrueVal, FalseVal,
 
     // Integer value.
     IntVal,
@@ -80,8 +86,8 @@ class TGLexer {
   // Information about the current token.
   const char *TokStart = nullptr;
   tgtok::TokKind CurCode = tgtok::TokKind::Eof;
-  std::string CurStrVal;  // This is valid for ID, STRVAL, VARNAME, CODEFRAGMENT
-  int64_t CurIntVal = 0;  // This is valid for INTVAL.
+  std::string CurStrVal; // This is valid for Id, StrVal, VarName, CodeFragment
+  int64_t CurIntVal = 0; // This is valid for IntVal.
 
   /// CurBuffer - This is the current buffer index we're lexing from as managed
   /// by the SourceMgr object.
diff --git a/llvm/lib/TableGen/TGParser.cpp b/llvm/lib/TableGen/TGParser.cpp
index 47f471ae2c4b..24949f0b2b4d 100644
--- a/llvm/lib/TableGen/TGParser.cpp
+++ b/llvm/lib/TableGen/TGParser.cpp
@@ -25,6 +25,7 @@
 #include <algorithm>
 #include <cassert>
 #include <cstdint>
+#include <limits>
 
 using namespace llvm;
 
@@ -94,7 +95,7 @@ static void checkConcrete(Record &R) {
     // done merely because existing targets have legitimate cases of
     // non-concrete variables in helper defs. Ideally, we'd introduce a
     // 'maybe' or 'optional' modifier instead of this.
-    if (RV.getPrefix())
+    if (RV.isNonconcreteOK())
       continue;
 
     if (Init *V = RV.getValue()) {
@@ -209,16 +210,16 @@ bool TGParser::SetValue(Record *CurRec, SMLoc Loc, Init *ValName,
     V = BitsInit::get(NewBits);
   }
 
-  if (RV->setValue(V)) {
+  if (RV->setValue(V, Loc)) {
     std::string InitType;
     if (BitsInit *BI = dyn_cast<BitsInit>(V))
       InitType = (Twine("' of type bit initializer with length ") +
                   Twine(BI->getNumBits())).str();
     else if (TypedInit *TI = dyn_cast<TypedInit>(V))
       InitType = (Twine("' of type '") + TI->getType()->getAsString()).str();
-    return Error(Loc, "Value '" + ValName->getAsUnquotedString() +
+    return Error(Loc, "Field '" + ValName->getAsUnquotedString() +
                           "' of type '" + RV->getType()->getAsString() +
-                          "' is incompatible with initializer '" +
+                          "' is incompatible with value '" +
                           V->getAsString() + InitType + "'");
   }
   return false;
@@ -451,6 +452,8 @@ bool TGParser::addDefOne(std::unique_ptr<Record> Rec) {
   Rec->resolveReferences();
   checkConcrete(*Rec);
 
+  CheckRecordAsserts(*Rec);
+
   if (!isa<StringInit>(Rec->getNameInit())) {
     PrintError(Rec->getLoc(), Twine("record name '") +
                                   Rec->getNameInit()->getAsString() +
@@ -481,11 +484,12 @@ bool TGParser::addDefOne(std::unique_ptr<Record> Rec) {
 // Parser Code
 //===----------------------------------------------------------------------===//
 
-/// isObjectStart - Return true if this is a valid first token for an Object.
+/// isObjectStart - Return true if this is a valid first token for a statement.
 static bool isObjectStart(tgtok::TokKind K) {
-  return K == tgtok::Class || K == tgtok::Def || K == tgtok::Defm ||
-         K == tgtok::Let || K == tgtok::MultiClass || K == tgtok::Foreach ||
-         K == tgtok::Defset || K == tgtok::Defvar || K == tgtok::If;
+  return K == tgtok::Assert || K == tgtok::Class || K == tgtok::Def ||
+         K == tgtok::Defm || K == tgtok::Defset || K == tgtok::Defvar ||
+         K == tgtok::Foreach || K == tgtok::If || K == tgtok::Let ||
+         K == tgtok::MultiClass;
 }
 
 bool TGParser::consume(tgtok::TokKind K) {
@@ -671,8 +675,10 @@ ParseSubMultiClassReference(MultiClass *CurMC) {
 
 /// ParseRangePiece - Parse a bit/value range.
 ///   RangePiece ::= INTVAL
+///   RangePiece ::= INTVAL '...' INTVAL
 ///   RangePiece ::= INTVAL '-' INTVAL
-///   RangePiece ::= INTVAL INTVAL
+///   RangePiece ::= INTVAL INTVAL 
+// The last two forms are deprecated.
 bool TGParser::ParseRangePiece(SmallVectorImpl<unsigned> &Ranges,
                                TypedInit *FirstItem) {
   Init *CurVal = FirstItem;
@@ -693,6 +699,8 @@ bool TGParser::ParseRangePiece(SmallVectorImpl<unsigned> &Ranges,
   default:
     Ranges.push_back(Start);
     return false;
+
+  case tgtok::dotdotdot:
   case tgtok::minus: {
     Lex.Lex(); // eat
 
@@ -795,8 +803,8 @@ bool TGParser::ParseOptionalBitList(SmallVectorImpl<unsigned> &Ranges) {
 RecTy *TGParser::ParseType() {
   switch (Lex.getCode()) {
   default: TokError("Unknown token when expecting a type"); return nullptr;
-  case tgtok::String: Lex.Lex(); return StringRecTy::get();
-  case tgtok::Code:   Lex.Lex(); return CodeRecTy::get();
+  case tgtok::String:
+  case tgtok::Code:   Lex.Lex(); return StringRecTy::get();
   case tgtok::Bit:    Lex.Lex(); return BitRecTy::get();
   case tgtok::Int:    Lex.Lex(); return IntRecTy::get();
   case tgtok::Dag:    Lex.Lex(); return DagRecTy::get();
@@ -809,12 +817,12 @@ RecTy *TGParser::ParseType() {
       TokError("expected '<' after bits type");
       return nullptr;
     }
-    if (Lex.Lex() != tgtok::IntVal) {  // Eat '<'
+    if (Lex.Lex() != tgtok::IntVal) { // Eat '<'
       TokError("expected integer in bits<n> type");
       return nullptr;
     }
     uint64_t Val = Lex.getCurIntVal();
-    if (Lex.Lex() != tgtok::greater) {  // Eat count.
+    if (Lex.Lex() != tgtok::greater) { // Eat count.
       TokError("expected '>' at end of bits<n> type");
       return nullptr;
     }
@@ -839,8 +847,7 @@ RecTy *TGParser::ParseType() {
   }
 }
 
-/// ParseIDValue - This is just like ParseIDValue above, but it assumes the ID
-/// has already been read.
+/// ParseIDValue
 Init *TGParser::ParseIDValue(Record *CurRec, StringInit *Name, SMLoc NameLoc,
                              IDParseMode Mode) {
   if (CurRec) {
@@ -902,14 +909,15 @@ Init *TGParser::ParseIDValue(Record *CurRec, StringInit *Name, SMLoc NameLoc,
 Init *TGParser::ParseOperation(Record *CurRec, RecTy *ItemType) {
   switch (Lex.getCode()) {
   default:
-    TokError("unknown operation");
+    TokError("unknown bang operator");
     return nullptr;
+  case tgtok::XNOT:
   case tgtok::XHead:
   case tgtok::XTail:
   case tgtok::XSize:
   case tgtok::XEmpty:
   case tgtok::XCast:
-  case tgtok::XGetOp: {  // Value ::= !unop '(' Value ')'
+  case tgtok::XGetDagOp: { // Value ::= !unop '(' Value ')'
     UnOpInit::UnaryOp Code;
     RecTy *Type = nullptr;
 
@@ -927,6 +935,11 @@ Init *TGParser::ParseOperation(Record *CurRec, RecTy *ItemType) {
       }
 
       break;
+    case tgtok::XNOT:
+      Lex.Lex();  // eat the operation
+      Code = UnOpInit::NOT;
+      Type = IntRecTy::get();
+      break;
     case tgtok::XHead:
       Lex.Lex();  // eat the operation
       Code = UnOpInit::HEAD;
@@ -945,12 +958,12 @@ Init *TGParser::ParseOperation(Record *CurRec, RecTy *ItemType) {
       Code = UnOpInit::EMPTY;
       Type = IntRecTy::get();
       break;
-    case tgtok::XGetOp:
+    case tgtok::XGetDagOp:
       Lex.Lex();  // eat the operation
       if (Lex.getCode() == tgtok::less) {
         // Parse an optional type suffix, so that you can say
-        // !getop<BaseClass>(someDag) as a shorthand for
-        // !cast<BaseClass>(!getop(someDag)).
+        // !getdagop<BaseClass>(someDag) as a shorthand for
+        // !cast<BaseClass>(!getdagop(someDag)).
         Type = ParseOperatorType();
 
         if (!Type) {
@@ -959,13 +972,13 @@ Init *TGParser::ParseOperation(Record *CurRec, RecTy *ItemType) {
         }
 
         if (!isa<RecordRecTy>(Type)) {
-          TokError("type for !getop must be a record type");
+          TokError("type for !getdagop must be a record type");
           // but keep parsing, to consume the operand
         }
       } else {
         Type = RecordRecTy::get({});
       }
-      Code = UnOpInit::GETOP;
+      Code = UnOpInit::GETDAGOP;
       break;
     }
     if (!consume(tgtok::l_paren)) {
@@ -976,56 +989,58 @@ Init *TGParser::ParseOperation(Record *CurRec, RecTy *ItemType) {
     Init *LHS = ParseValue(CurRec);
     if (!LHS) return nullptr;
 
-    if (Code == UnOpInit::HEAD ||
-        Code == UnOpInit::TAIL ||
-        Code == UnOpInit::EMPTY) {
+    if (Code == UnOpInit::EMPTY || Code == UnOpInit::SIZE) {
       ListInit *LHSl = dyn_cast<ListInit>(LHS);
       StringInit *LHSs = dyn_cast<StringInit>(LHS);
+      DagInit *LHSd = dyn_cast<DagInit>(LHS);
       TypedInit *LHSt = dyn_cast<TypedInit>(LHS);
-      if (!LHSl && !LHSs && !LHSt) {
-        TokError("expected list or string type argument in unary operator");
+      if (!LHSl && !LHSs && !LHSd && !LHSt) {
+        TokError("expected string, list, or dag type argument in unary operator");
         return nullptr;
       }
       if (LHSt) {
         ListRecTy *LType = dyn_cast<ListRecTy>(LHSt->getType());
         StringRecTy *SType = dyn_cast<StringRecTy>(LHSt->getType());
-        if (!LType && !SType) {
-          TokError("expected list or string type argument in unary operator");
+        DagRecTy *DType = dyn_cast<DagRecTy>(LHSt->getType());
+        if (!LType && !SType && !DType) {
+          TokError("expected string, list, or dag type argument in unary operator");
           return nullptr;
         }
       }
+    }
 
-      if (Code == UnOpInit::HEAD || Code == UnOpInit::TAIL ||
-          Code == UnOpInit::SIZE) {
-        if (!LHSl && !LHSt) {
+    if (Code == UnOpInit::HEAD || Code == UnOpInit::TAIL) {
+      ListInit *LHSl = dyn_cast<ListInit>(LHS);
+      TypedInit *LHSt = dyn_cast<TypedInit>(LHS);
+      if (!LHSl && !LHSt) {
+        TokError("expected list type argument in unary operator");
+        return nullptr;
+      }
+      if (LHSt) {
+        ListRecTy *LType = dyn_cast<ListRecTy>(LHSt->getType());
+        if (!LType) {
           TokError("expected list type argument in unary operator");
           return nullptr;
         }
       }
 
-      if (Code == UnOpInit::HEAD || Code == UnOpInit::TAIL) {
-        if (LHSl && LHSl->empty()) {
-          TokError("empty list argument in unary operator");
+      if (LHSl && LHSl->empty()) {
+        TokError("empty list argument in unary operator");
+        return nullptr;
+      }
+      if (LHSl) {
+        Init *Item = LHSl->getElement(0);
+        TypedInit *Itemt = dyn_cast<TypedInit>(Item);
+        if (!Itemt) {
+          TokError("untyped list element in unary operator");
           return nullptr;
         }
-        if (LHSl) {
-          Init *Item = LHSl->getElement(0);
-          TypedInit *Itemt = dyn_cast<TypedInit>(Item);
-          if (!Itemt) {
-            TokError("untyped list element in unary operator");
-            return nullptr;
-          }
-          Type = (Code == UnOpInit::HEAD) ? Itemt->getType()
-                                          : ListRecTy::get(Itemt->getType());
-        } else {
-          assert(LHSt && "expected list type argument in unary operator");
-          ListRecTy *LType = dyn_cast<ListRecTy>(LHSt->getType());
-          if (!LType) {
-            TokError("expected list type argument in unary operator");
-            return nullptr;
-          }
-          Type = (Code == UnOpInit::HEAD) ? LType->getElementType() : LType;
-        }
+        Type = (Code == UnOpInit::HEAD) ? Itemt->getType()
+                                        : ListRecTy::get(Itemt->getType());
+      } else {
+        assert(LHSt && "expected list type argument in unary operator");
+        ListRecTy *LType = dyn_cast<ListRecTy>(LHSt->getType());
+        Type = (Code == UnOpInit::HEAD) ? LType->getElementType() : LType;
       }
     }
 
@@ -1063,9 +1078,11 @@ Init *TGParser::ParseOperation(Record *CurRec, RecTy *ItemType) {
 
   case tgtok::XConcat:
   case tgtok::XADD:
+  case tgtok::XSUB:
   case tgtok::XMUL:
   case tgtok::XAND:
   case tgtok::XOR:
+  case tgtok::XXOR:
   case tgtok::XSRA:
   case tgtok::XSRL:
   case tgtok::XSHL:
@@ -1078,7 +1095,8 @@ Init *TGParser::ParseOperation(Record *CurRec, RecTy *ItemType) {
   case tgtok::XListConcat:
   case tgtok::XListSplat:
   case tgtok::XStrConcat:
-  case tgtok::XSetOp: {  // Value ::= !binop '(' Value ',' Value ')'
+  case tgtok::XInterleave:
+  case tgtok::XSetDagOp: { // Value ::= !binop '(' Value ',' Value ')'
     tgtok::TokKind OpTok = Lex.getCode();
     SMLoc OpLoc = Lex.getLoc();
     Lex.Lex();  // eat the operation
@@ -1088,9 +1106,11 @@ Init *TGParser::ParseOperation(Record *CurRec, RecTy *ItemType) {
     default: llvm_unreachable("Unhandled code!");
     case tgtok::XConcat: Code = BinOpInit::CONCAT; break;
     case tgtok::XADD:    Code = BinOpInit::ADD; break;
+    case tgtok::XSUB:    Code = BinOpInit::SUB; break;
     case tgtok::XMUL:    Code = BinOpInit::MUL; break;
     case tgtok::XAND:    Code = BinOpInit::AND; break;
     case tgtok::XOR:     Code = BinOpInit::OR; break;
+    case tgtok::XXOR:    Code = BinOpInit::XOR; break;
     case tgtok::XSRA:    Code = BinOpInit::SRA; break;
     case tgtok::XSRL:    Code = BinOpInit::SRL; break;
     case tgtok::XSHL:    Code = BinOpInit::SHL; break;
@@ -1101,9 +1121,10 @@ Init *TGParser::ParseOperation(Record *CurRec, RecTy *ItemType) {
     case tgtok::XGe:     Code = BinOpInit::GE; break;
     case tgtok::XGt:     Code = BinOpInit::GT; break;
     case tgtok::XListConcat: Code = BinOpInit::LISTCONCAT; break;
-    case tgtok::XListSplat: Code = BinOpInit::LISTSPLAT; break;
-    case tgtok::XStrConcat: Code = BinOpInit::STRCONCAT; break;
-    case tgtok::XSetOp: Code = BinOpInit::SETOP; break;
+    case tgtok::XListSplat:  Code = BinOpInit::LISTSPLAT; break;
+    case tgtok::XStrConcat:  Code = BinOpInit::STRCONCAT; break;
+    case tgtok::XInterleave: Code = BinOpInit::INTERLEAVE; break;
+    case tgtok::XSetDagOp:   Code = BinOpInit::SETDAGOP; break;
     }
 
     RecTy *Type = nullptr;
@@ -1112,31 +1133,30 @@ Init *TGParser::ParseOperation(Record *CurRec, RecTy *ItemType) {
     default:
       llvm_unreachable("Unhandled code!");
     case tgtok::XConcat:
-    case tgtok::XSetOp:
+    case tgtok::XSetDagOp:
       Type = DagRecTy::get();
       ArgType = DagRecTy::get();
       break;
     case tgtok::XAND:
     case tgtok::XOR:
+    case tgtok::XXOR:
     case tgtok::XSRA:
     case tgtok::XSRL:
     case tgtok::XSHL:
     case tgtok::XADD:
+    case tgtok::XSUB:
     case tgtok::XMUL:
       Type = IntRecTy::get();
       ArgType = IntRecTy::get();
       break;
     case tgtok::XEq:
     case tgtok::XNe:
-      Type = BitRecTy::get();
-      // ArgType for Eq / Ne is not known at this point
-      break;
     case tgtok::XLe:
     case tgtok::XLt:
     case tgtok::XGe:
     case tgtok::XGt:
       Type = BitRecTy::get();
-      ArgType = IntRecTy::get();
+      // ArgType for the comparison operators is not yet known.
       break;
     case tgtok::XListConcat:
       // We don't know the list type until we parse the first argument
@@ -1149,6 +1169,9 @@ Init *TGParser::ParseOperation(Record *CurRec, RecTy *ItemType) {
       Type = StringRecTy::get();
       ArgType = StringRecTy::get();
       break;
+    case tgtok::XInterleave:
+      Type = StringRecTy::get();
+      // The first argument type is not yet known.
     }
 
     if (Type && ItemType && !Type->typeIsConvertibleTo(ItemType)) {
@@ -1165,6 +1188,8 @@ Init *TGParser::ParseOperation(Record *CurRec, RecTy *ItemType) {
 
     SmallVector<Init*, 2> InitList;
 
+    // Note that this loop consumes an arbitrary number of arguments.
+    // The actual count is checked later.
     for (;;) {
       SMLoc InitLoc = Lex.getLoc();
       InitList.push_back(ParseValue(CurRec, ArgType));
@@ -1177,7 +1202,9 @@ Init *TGParser::ParseOperation(Record *CurRec, RecTy *ItemType) {
         return nullptr;
       }
       RecTy *ListType = InitListBack->getType();
+
       if (!ArgType) {
+        // Argument type must be determined from the argument itself.
         ArgType = ListType;
 
         switch (Code) {
@@ -1218,15 +1245,54 @@ Init *TGParser::ParseOperation(Record *CurRec, RecTy *ItemType) {
         case BinOpInit::EQ:
         case BinOpInit::NE:
           if (!ArgType->typeIsConvertibleTo(IntRecTy::get()) &&
+              !ArgType->typeIsConvertibleTo(StringRecTy::get()) &&
+              !ArgType->typeIsConvertibleTo(RecordRecTy::get({}))) {
+            Error(InitLoc, Twine("expected bit, bits, int, string, or record; "
+                                 "got value of type '") + ArgType->getAsString() + 
+                                 "'");
+            return nullptr;
+          }
+          break;
+        case BinOpInit::LE:
+        case BinOpInit::LT:
+        case BinOpInit::GE:
+        case BinOpInit::GT:
+          if (!ArgType->typeIsConvertibleTo(IntRecTy::get()) &&
               !ArgType->typeIsConvertibleTo(StringRecTy::get())) {
-            Error(InitLoc, Twine("expected int, bits, or string; got value of "
-                                 "type '") + ArgType->getAsString() + "'");
+            Error(InitLoc, Twine("expected bit, bits, int, or string; "
+                                 "got value of type '") + ArgType->getAsString() + 
+                                 "'");
             return nullptr;
           }
           break;
+        case BinOpInit::INTERLEAVE:
+          switch (InitList.size()) {
+          case 1: // First argument must be a list of strings or integers.
+            if (ArgType != StringRecTy::get()->getListTy() &&
+                !ArgType->typeIsConvertibleTo(IntRecTy::get()->getListTy())) {
+              Error(InitLoc, Twine("expected list of string, int, bits, or bit; "
+                                   "got value of type '") +
+                                   ArgType->getAsString() + "'");
+              return nullptr;
+            }
+            break;
+          case 2: // Second argument must be a string.
+            if (!isa<StringRecTy>(ArgType)) {
+              Error(InitLoc, Twine("expected second argument to be a string, "
+                                   "got value of type '") +
+                                 ArgType->getAsString() + "'");
+              return nullptr;
+            }
+            break;
+          default: ;
+          }
+          ArgType = nullptr; // Broken invariant: types not identical.
+          break;
         default: llvm_unreachable("other ops have fixed argument types");
         }
+
       } else {
+        // Desired argument type is a known and in ArgType.
         RecTy *Resolved = resolveTypes(ArgType, ListType);
         if (!Resolved) {
           Error(InitLoc, Twine("expected value of type '") +
@@ -1234,8 +1300,9 @@ Init *TGParser::ParseOperation(Record *CurRec, RecTy *ItemType) {
                              ListType->getAsString() + "'");
           return nullptr;
         }
-        if (Code != BinOpInit::ADD && Code != BinOpInit::AND &&
-            Code != BinOpInit::OR && Code != BinOpInit::SRA &&
+        if (Code != BinOpInit::ADD && Code != BinOpInit::SUB &&
+            Code != BinOpInit::AND && Code != BinOpInit::OR &&
+            Code != BinOpInit::XOR && Code != BinOpInit::SRA &&
             Code != BinOpInit::SRL && Code != BinOpInit::SHL &&
             Code != BinOpInit::MUL)
           ArgType = Resolved;
@@ -1244,7 +1311,7 @@ Init *TGParser::ParseOperation(Record *CurRec, RecTy *ItemType) {
       // Deal with BinOps whose arguments have different types, by
       // rewriting ArgType in between them.
       switch (Code) {
-        case BinOpInit::SETOP:
+        case BinOpInit::SETDAGOP:
           // After parsing the first dag argument, switch to expecting
           // a record, with no restriction on its superclasses.
           ArgType = RecordRecTy::get({});
@@ -1274,7 +1341,7 @@ Init *TGParser::ParseOperation(Record *CurRec, RecTy *ItemType) {
     if (Code == BinOpInit::STRCONCAT || Code == BinOpInit::LISTCONCAT ||
         Code == BinOpInit::CONCAT || Code == BinOpInit::ADD ||
         Code == BinOpInit::AND || Code == BinOpInit::OR ||
-        Code == BinOpInit::MUL) {
+        Code == BinOpInit::XOR || Code == BinOpInit::MUL) {
       while (InitList.size() > 2) {
         Init *RHS = InitList.pop_back_val();
         RHS = (BinOpInit::get(Code, InitList.back(), RHS, Type))->Fold(CurRec);
@@ -1290,118 +1357,14 @@ Init *TGParser::ParseOperation(Record *CurRec, RecTy *ItemType) {
     return nullptr;
   }
 
-  case tgtok::XForEach: { // Value ::= !foreach '(' Id ',' Value ',' Value ')'
-    SMLoc OpLoc = Lex.getLoc();
-    Lex.Lex(); // eat the operation
-    if (Lex.getCode() != tgtok::l_paren) {
-      TokError("expected '(' after !foreach");
-      return nullptr;
-    }
-
-    if (Lex.Lex() != tgtok::Id) { // eat the '('
-      TokError("first argument of !foreach must be an identifier");
-      return nullptr;
-    }
-
-    Init *LHS = StringInit::get(Lex.getCurStrVal());
-    Lex.Lex();
-
-    if (CurRec && CurRec->getValue(LHS)) {
-      TokError((Twine("iteration variable '") + LHS->getAsString() +
-                "' already defined")
-                   .str());
-      return nullptr;
-    }
-
-    if (!consume(tgtok::comma)) { // eat the id
-      TokError("expected ',' in ternary operator");
-      return nullptr;
-    }
-
-    Init *MHS = ParseValue(CurRec);
-    if (!MHS)
-      return nullptr;
-
-    if (!consume(tgtok::comma)) {
-      TokError("expected ',' in ternary operator");
-      return nullptr;
-    }
-
-    TypedInit *MHSt = dyn_cast<TypedInit>(MHS);
-    if (!MHSt) {
-      TokError("could not get type of !foreach input");
-      return nullptr;
-    }
-
-    RecTy *InEltType = nullptr;
-    RecTy *OutEltType = nullptr;
-    bool IsDAG = false;
-
-    if (ListRecTy *InListTy = dyn_cast<ListRecTy>(MHSt->getType())) {
-      InEltType = InListTy->getElementType();
-      if (ItemType) {
-        if (ListRecTy *OutListTy = dyn_cast<ListRecTy>(ItemType)) {
-          OutEltType = OutListTy->getElementType();
-        } else {
-          Error(OpLoc,
-                "expected value of type '" + Twine(ItemType->getAsString()) +
-                "', but got !foreach of list type");
-          return nullptr;
-        }
-      }
-    } else if (DagRecTy *InDagTy = dyn_cast<DagRecTy>(MHSt->getType())) {
-      InEltType = InDagTy;
-      if (ItemType && !isa<DagRecTy>(ItemType)) {
-        Error(OpLoc,
-              "expected value of type '" + Twine(ItemType->getAsString()) +
-              "', but got !foreach of dag type");
-        return nullptr;
-      }
-      IsDAG = true;
-    } else {
-      TokError("!foreach must have list or dag input");
-      return nullptr;
-    }
-
-    // We need to create a temporary record to provide a scope for the iteration
-    // variable while parsing top-level foreach's.
-    std::unique_ptr<Record> ParseRecTmp;
-    Record *ParseRec = CurRec;
-    if (!ParseRec) {
-      ParseRecTmp = std::make_unique<Record>(".parse", ArrayRef<SMLoc>{}, Records);
-      ParseRec = ParseRecTmp.get();
-    }
-
-    ParseRec->addValue(RecordVal(LHS, InEltType, false));
-    Init *RHS = ParseValue(ParseRec, OutEltType);
-    ParseRec->removeValue(LHS);
-    if (!RHS)
-      return nullptr;
-
-    if (!consume(tgtok::r_paren)) {
-      TokError("expected ')' in binary operator");
-      return nullptr;
-    }
-
-    RecTy *OutType;
-    if (IsDAG) {
-      OutType = InEltType;
-    } else {
-      TypedInit *RHSt = dyn_cast<TypedInit>(RHS);
-      if (!RHSt) {
-        TokError("could not get type of !foreach result");
-        return nullptr;
-      }
-      OutType = RHSt->getType()->getListTy();
-    }
-
-    return (TernOpInit::get(TernOpInit::FOREACH, LHS, MHS, RHS, OutType))
-        ->Fold(CurRec);
+  case tgtok::XForEach:
+  case tgtok::XFilter: {
+    return ParseOperationForEachFilter(CurRec, ItemType);
   }
 
   case tgtok::XDag:
   case tgtok::XIf:
-  case tgtok::XSubst: {  // Value ::= !ternop '(' Value ',' Value ',' Value ')'
+  case tgtok::XSubst: { // Value ::= !ternop '(' Value ',' Value ',' Value ')'
     TernOpInit::TernaryOp Code;
     RecTy *Type = nullptr;
 
@@ -1536,11 +1499,14 @@ Init *TGParser::ParseOperation(Record *CurRec, RecTy *ItemType) {
     return (TernOpInit::get(Code, LHS, MHS, RHS, Type))->Fold(CurRec);
   }
 
+  case tgtok::XSubstr:
+    return ParseOperationSubstr(CurRec, ItemType);
+
   case tgtok::XCond:
     return ParseOperationCond(CurRec, ItemType);
 
   case tgtok::XFoldl: {
-    // Value ::= !foldl '(' Id ',' Id ',' Value ',' Value ',' Value ')'
+    // Value ::= !foldl '(' Value ',' Value ',' Id ',' Id ',' Expr ')'
     Lex.Lex(); // eat the operation
     if (!consume(tgtok::l_paren)) {
       TokError("expected '(' after !foldl");
@@ -1623,8 +1589,8 @@ Init *TGParser::ParseOperation(Record *CurRec, RecTy *ItemType) {
     }
     Lex.Lex(); // eat the ','
 
-    // We need to create a temporary record to provide a scope for the iteration
-    // variable while parsing top-level foreach's.
+    // We need to create a temporary record to provide a scope for the
+    // two variables.
     std::unique_ptr<Record> ParseRecTmp;
     Record *ParseRec = CurRec;
     if (!ParseRec) {
@@ -1632,8 +1598,9 @@ Init *TGParser::ParseOperation(Record *CurRec, RecTy *ItemType) {
       ParseRec = ParseRecTmp.get();
     }
 
-    ParseRec->addValue(RecordVal(A, Start->getType(), false));
-    ParseRec->addValue(RecordVal(B, ListType->getElementType(), false));
+    ParseRec->addValue(RecordVal(A, Start->getType(), RecordVal::FK_Normal));
+    ParseRec->addValue(RecordVal(B, ListType->getElementType(),
+                                 RecordVal::FK_Normal));
     Init *ExprUntyped = ParseValue(ParseRec);
     ParseRec->removeValue(A);
     ParseRec->removeValue(B);
@@ -1677,6 +1644,9 @@ RecTy *TGParser::ParseOperatorType() {
     return nullptr;
   }
 
+  if (Lex.getCode() == tgtok::Code)
+    TokError("the 'code' type is not allowed in bang operators; use 'string'");
+
   Type = ParseType();
 
   if (!Type) {
@@ -1692,6 +1662,221 @@ RecTy *TGParser::ParseOperatorType() {
   return Type;
 }
 
+/// Parse the !substr operation. Return null on error.
+///
+/// Substr ::= !substr(string, start-int [, length-int]) => string
+Init *TGParser::ParseOperationSubstr(Record *CurRec, RecTy *ItemType) {
+  TernOpInit::TernaryOp Code = TernOpInit::SUBSTR;
+  RecTy *Type = StringRecTy::get();
+
+  Lex.Lex(); // eat the operation
+
+  if (!consume(tgtok::l_paren)) {
+    TokError("expected '(' after !substr operator");
+    return nullptr;
+  }
+
+  Init *LHS = ParseValue(CurRec);
+  if (!LHS)
+    return nullptr;
+
+  if (!consume(tgtok::comma)) {
+    TokError("expected ',' in !substr operator");
+    return nullptr;
+  }
+
+  SMLoc MHSLoc = Lex.getLoc();
+  Init *MHS = ParseValue(CurRec);
+  if (!MHS)
+    return nullptr;
+
+  SMLoc RHSLoc = Lex.getLoc();
+  Init *RHS;
+  if (consume(tgtok::comma)) {
+    RHSLoc = Lex.getLoc();
+    RHS = ParseValue(CurRec);
+    if (!RHS)
+      return nullptr;
+  } else {
+    RHS = IntInit::get(std::numeric_limits<int64_t>::max());
+  }
+
+  if (!consume(tgtok::r_paren)) {
+    TokError("expected ')' in !substr operator");
+    return nullptr;
+  }
+
+  if (ItemType && !Type->typeIsConvertibleTo(ItemType)) {
+    Error(RHSLoc, Twine("expected value of type '") +
+                  ItemType->getAsString() + "', got '" +
+                  Type->getAsString() + "'");
+  }
+
+  TypedInit *LHSt = dyn_cast<TypedInit>(LHS);
+  if (!LHSt && !isa<UnsetInit>(LHS)) {
+    TokError("could not determine type of the string in !substr");
+    return nullptr;
+  }
+  if (LHSt && !isa<StringRecTy>(LHSt->getType())) {
+    TokError(Twine("expected string, got type '") +
+             LHSt->getType()->getAsString() + "'");
+    return nullptr;
+  }
+
+  TypedInit *MHSt = dyn_cast<TypedInit>(MHS);
+  if (!MHSt && !isa<UnsetInit>(MHS)) {
+    TokError("could not determine type of the start position in !substr");
+    return nullptr;
+  }
+  if (MHSt && !isa<IntRecTy>(MHSt->getType())) {
+    Error(MHSLoc, Twine("expected int, got type '") +
+                      MHSt->getType()->getAsString() + "'");
+    return nullptr;
+  }
+
+  if (RHS) {
+    TypedInit *RHSt = dyn_cast<TypedInit>(RHS);
+    if (!RHSt && !isa<UnsetInit>(RHS)) {
+      TokError("could not determine type of the length in !substr");
+      return nullptr;
+    }
+    if (RHSt && !isa<IntRecTy>(RHSt->getType())) {
+      TokError(Twine("expected int, got type '") +
+               RHSt->getType()->getAsString() + "'");
+      return nullptr;
+    }
+  }
+
+  return (TernOpInit::get(Code, LHS, MHS, RHS, Type))->Fold(CurRec);
+}
+
+/// Parse the !foreach and !filter operations. Return null on error.
+///
+/// ForEach ::= !foreach(ID, list-or-dag, expr) => list<expr type>
+/// Filter  ::= !foreach(ID, list, predicate) ==> list<list type>
+Init *TGParser::ParseOperationForEachFilter(Record *CurRec, RecTy *ItemType) { 
+  SMLoc OpLoc = Lex.getLoc();
+  tgtok::TokKind Operation = Lex.getCode();
+  Lex.Lex(); // eat the operation
+  if (Lex.getCode() != tgtok::l_paren) {
+    TokError("expected '(' after !foreach/!filter");
+    return nullptr;
+  }
+
+  if (Lex.Lex() != tgtok::Id) { // eat the '('
+    TokError("first argument of !foreach/!filter must be an identifier");
+    return nullptr;
+  }
+
+  Init *LHS = StringInit::get(Lex.getCurStrVal());
+  Lex.Lex(); // eat the ID.
+
+  if (CurRec && CurRec->getValue(LHS)) {
+    TokError((Twine("iteration variable '") + LHS->getAsString() +
+              "' is already defined")
+                 .str());
+    return nullptr;
+  }
+
+  if (!consume(tgtok::comma)) {
+    TokError("expected ',' in !foreach/!filter");
+    return nullptr;
+  }
+
+  Init *MHS = ParseValue(CurRec);
+  if (!MHS)
+    return nullptr;
+
+  if (!consume(tgtok::comma)) {
+    TokError("expected ',' in !foreach/!filter");
+    return nullptr;
+  }
+
+  TypedInit *MHSt = dyn_cast<TypedInit>(MHS);
+  if (!MHSt) {
+    TokError("could not get type of !foreach/!filter list or dag");
+    return nullptr;
+  }
+
+  RecTy *InEltType = nullptr;
+  RecTy *ExprEltType = nullptr;
+  bool IsDAG = false;
+
+  if (ListRecTy *InListTy = dyn_cast<ListRecTy>(MHSt->getType())) {
+    InEltType = InListTy->getElementType();
+    if (ItemType) {
+      if (ListRecTy *OutListTy = dyn_cast<ListRecTy>(ItemType)) {
+        ExprEltType = (Operation == tgtok::XForEach)
+                          ? OutListTy->getElementType()
+                          : IntRecTy::get();
+      } else {
+        Error(OpLoc,
+              "expected value of type '" +
+                  Twine(ItemType->getAsString()) +
+                  "', but got list type");
+        return nullptr;
+      }
+    }
+  } else if (DagRecTy *InDagTy = dyn_cast<DagRecTy>(MHSt->getType())) {
+    if (Operation == tgtok::XFilter) {
+      TokError("!filter must have a list argument");
+      return nullptr;
+    }
+    InEltType = InDagTy;
+    if (ItemType && !isa<DagRecTy>(ItemType)) {
+      Error(OpLoc,
+            "expected value of type '" + Twine(ItemType->getAsString()) +
+                "', but got dag type");
+      return nullptr;
+    }
+    IsDAG = true;
+  } else {
+    if (Operation == tgtok::XForEach)
+      TokError("!foreach must have a list or dag argument");
+    else
+      TokError("!filter must have a list argument");
+    return nullptr;
+  }
+
+  // We need to create a temporary record to provide a scope for the
+  // iteration variable.
+  std::unique_ptr<Record> ParseRecTmp;
+  Record *ParseRec = CurRec;
+  if (!ParseRec) {
+    ParseRecTmp =
+        std::make_unique<Record>(".parse", ArrayRef<SMLoc>{}, Records);
+    ParseRec = ParseRecTmp.get();
+  }
+
+  ParseRec->addValue(RecordVal(LHS, InEltType, RecordVal::FK_Normal));
+  Init *RHS = ParseValue(ParseRec, ExprEltType);
+  ParseRec->removeValue(LHS);
+  if (!RHS)
+    return nullptr;
+
+  if (!consume(tgtok::r_paren)) {
+    TokError("expected ')' in !foreach/!filter");
+    return nullptr;
+  }
+
+  RecTy *OutType = InEltType;
+  if (Operation == tgtok::XForEach && !IsDAG) {
+    TypedInit *RHSt = dyn_cast<TypedInit>(RHS);
+    if (!RHSt) {
+      TokError("could not get type of !foreach result expression");
+      return nullptr;
+    }
+    OutType = RHSt->getType()->getListTy();
+  } else if (Operation == tgtok::XFilter) {
+    OutType = InEltType->getListTy();
+  }    
+
+  return (TernOpInit::get((Operation == tgtok::XForEach) ? TernOpInit::FOREACH
+                                                         : TernOpInit::FILTER,
+                          LHS, MHS, RHS, OutType))
+      ->Fold(CurRec);
+}
+
 Init *TGParser::ParseOperationCond(Record *CurRec, RecTy *ItemType) {
   Lex.Lex();  // eat the operation 'cond'
 
@@ -1783,6 +1968,7 @@ Init *TGParser::ParseOperationCond(Record *CurRec, RecTy *ItemType) {
 ///   SimpleValue ::= '(' IDValue DagArgList ')'
 ///   SimpleValue ::= CONCATTOK '(' Value ',' Value ')'
 ///   SimpleValue ::= ADDTOK '(' Value ',' Value ')'
+///   SimpleValue ::= SUBTOK '(' Value ',' Value ')'
 ///   SimpleValue ::= SHLTOK '(' Value ',' Value ')'
 ///   SimpleValue ::= SRATOK '(' Value ',' Value ')'
 ///   SimpleValue ::= SRLTOK '(' Value ',' Value ')'
@@ -1795,8 +1981,20 @@ Init *TGParser::ParseSimpleValue(Record *CurRec, RecTy *ItemType,
                                  IDParseMode Mode) {
   Init *R = nullptr;
   switch (Lex.getCode()) {
-  default: TokError("Unknown token when parsing a value"); break;
-  case tgtok::IntVal: R = IntInit::get(Lex.getCurIntVal()); Lex.Lex(); break;
+  default: TokError("Unknown or reserved token when parsing a value"); break;
+
+  case tgtok::TrueVal:
+    R = IntInit::get(1);
+    Lex.Lex();
+    break;
+  case tgtok::FalseVal:
+    R = IntInit::get(0);
+    Lex.Lex();
+    break;
+  case tgtok::IntVal:
+    R = IntInit::get(Lex.getCurIntVal());
+    Lex.Lex();
+    break;
   case tgtok::BinaryIntVal: {
     auto BinaryVal = Lex.getCurBinaryIntVal();
     SmallVector<Init*, 16> Bits(BinaryVal.second);
@@ -1820,7 +2018,7 @@ Init *TGParser::ParseSimpleValue(Record *CurRec, RecTy *ItemType,
     break;
   }
   case tgtok::CodeFragment:
-    R = CodeInit::get(Lex.getCurStrVal(), Lex.getLoc());
+    R = StringInit::get(Lex.getCurStrVal(), StringInit::SF_Code);
     Lex.Lex();
     break;
   case tgtok::question:
@@ -1951,7 +2149,7 @@ Init *TGParser::ParseSimpleValue(Record *CurRec, RecTy *ItemType,
     if (ItemType) {
       ListRecTy *ListType = dyn_cast<ListRecTy>(ItemType);
       if (!ListType) {
-        TokError(Twine("Type mismatch for list, expected list type, got ") +
+        TokError(Twine("Encountered a list when expecting a ") +
                  ItemType->getAsString());
         return nullptr;
       }
@@ -2035,7 +2233,7 @@ Init *TGParser::ParseSimpleValue(Record *CurRec, RecTy *ItemType,
   case tgtok::l_paren: {         // Value ::= '(' IDValue DagArgList ')'
     Lex.Lex();   // eat the '('
     if (Lex.getCode() != tgtok::Id && Lex.getCode() != tgtok::XCast &&
-        Lex.getCode() != tgtok::question && Lex.getCode() != tgtok::XGetOp) {
+        Lex.getCode() != tgtok::question && Lex.getCode() != tgtok::XGetDagOp) {
       TokError("expected identifier in dag init");
       return nullptr;
     }
@@ -2073,14 +2271,17 @@ Init *TGParser::ParseSimpleValue(Record *CurRec, RecTy *ItemType,
   case tgtok::XSize:
   case tgtok::XEmpty:
   case tgtok::XCast:
-  case tgtok::XGetOp:  // Value ::= !unop '(' Value ')'
+  case tgtok::XGetDagOp: // Value ::= !unop '(' Value ')'
   case tgtok::XIsA:
   case tgtok::XConcat:
   case tgtok::XDag:
   case tgtok::XADD:
+  case tgtok::XSUB:
   case tgtok::XMUL:
+  case tgtok::XNOT:
   case tgtok::XAND:
   case tgtok::XOR:
+  case tgtok::XXOR:
   case tgtok::XSRA:
   case tgtok::XSRL:
   case tgtok::XSHL:
@@ -2093,12 +2294,15 @@ Init *TGParser::ParseSimpleValue(Record *CurRec, RecTy *ItemType,
   case tgtok::XListConcat:
   case tgtok::XListSplat:
   case tgtok::XStrConcat:
-  case tgtok::XSetOp:   // Value ::= !binop '(' Value ',' Value ')'
+  case tgtok::XInterleave:
+  case tgtok::XSetDagOp: // Value ::= !binop '(' Value ',' Value ')'
   case tgtok::XIf:
   case tgtok::XCond:
   case tgtok::XFoldl:
   case tgtok::XForEach:
-  case tgtok::XSubst: {  // Value ::= !ternop '(' Value ',' Value ',' Value ')'
+  case tgtok::XFilter:
+  case tgtok::XSubst:
+  case tgtok::XSubstr: { // Value ::= !ternop '(' Value ',' Value ',' Value ')'
     return ParseOperation(CurRec, ItemType);
   }
   }
@@ -2106,7 +2310,7 @@ Init *TGParser::ParseSimpleValue(Record *CurRec, RecTy *ItemType,
   return R;
 }
 
-/// ParseValue - Parse a tblgen value.  This returns null on error.
+/// ParseValue - Parse a TableGen value. This returns null on error.
 ///
 ///   Value       ::= SimpleValue ValueSuffix*
 ///   ValueSuffix ::= '{' BitList '}'
@@ -2167,8 +2371,8 @@ Init *TGParser::ParseValue(Record *CurRec, RecTy *ItemType, IDParseMode Mode) {
       }
       break;
     }
-    case tgtok::period: {
-      if (Lex.Lex() != tgtok::Id) {  // eat the .
+    case tgtok::dot: {
+      if (Lex.Lex() != tgtok::Id) { // eat the .
         TokError("expected field identifier after '.'");
         return nullptr;
       }
@@ -2195,6 +2399,8 @@ Init *TGParser::ParseValue(Record *CurRec, RecTy *ItemType, IDParseMode Mode) {
       if (isa<ListRecTy>(LHS->getType())) {
         Lex.Lex();  // Eat the '#'.
 
+        assert(Mode == ParseValueMode && "encountered paste of lists in name");
+
         switch (Lex.getCode()) {
         case tgtok::colon:
         case tgtok::semi:
@@ -2202,8 +2408,11 @@ Init *TGParser::ParseValue(Record *CurRec, RecTy *ItemType, IDParseMode Mode) {
           Result = LHS; // trailing paste, ignore.
           break;
         default:
-          Init *RHSResult = ParseValue(CurRec, ItemType, ParseNameMode);
+          Init *RHSResult = ParseValue(CurRec, ItemType, ParseValueMode);
+          if (!RHSResult)
+            return nullptr;
           Result = BinOpInit::getListConcat(LHS, RHSResult);
+          break;
         }
         break;
       }
@@ -2239,6 +2448,8 @@ Init *TGParser::ParseValue(Record *CurRec, RecTy *ItemType, IDParseMode Mode) {
 
       default:
         Init *RHSResult = ParseValue(CurRec, nullptr, ParseNameMode);
+        if (!RHSResult)
+          return nullptr;
         RHS = dyn_cast<TypedInit>(RHSResult);
         if (!RHS) {
           Error(PasteLoc, "RHS of paste is not typed!");
@@ -2410,8 +2621,10 @@ Init *TGParser::ParseDeclaration(Record *CurRec,
                              "::");
   }
 
-  // Add the value.
-  if (AddValue(CurRec, IdLoc, RecordVal(DeclName, Type, HasField)))
+  // Add the field to the record.
+  if (AddValue(CurRec, IdLoc, RecordVal(DeclName, IdLoc, Type,
+                                        HasField ? RecordVal::FK_NonconcreteOK
+                                                 : RecordVal::FK_Normal)))
     return nullptr;
 
   // If a value is present, parse it.
@@ -2552,12 +2765,16 @@ bool TGParser::ParseTemplateArgList(Record *CurRec) {
   return false;
 }
 
-/// ParseBodyItem - Parse a single item at within the body of a def or class.
+/// ParseBodyItem - Parse a single item within the body of a def or class.
 ///
 ///   BodyItem ::= Declaration ';'
 ///   BodyItem ::= LET ID OptionalBitList '=' Value ';'
 ///   BodyItem ::= Defvar
+///   BodyItem ::= Assert
 bool TGParser::ParseBodyItem(Record *CurRec) {
+  if (Lex.getCode() == tgtok::Assert)
+    return ParseAssert(nullptr, CurRec);
+
   if (Lex.getCode() == tgtok::Defvar)
     return ParseDefvar();
 
@@ -2619,7 +2836,7 @@ bool TGParser::ParseBody(Record *CurRec) {
     return false;
 
   if (!consume(tgtok::l_brace))
-    return TokError("Expected ';' or '{' to start body");
+    return TokError("Expected '{' to start body or ';' for declaration only");
 
   // An object body introduces a new scope for local variables.
   TGLocalVarScope *BodyScope = PushLocalScope();
@@ -2632,6 +2849,14 @@ bool TGParser::ParseBody(Record *CurRec) {
 
   // Eat the '}'.
   Lex.Lex();
+
+  // If we have a semicolon, print a gentle error.
+  SMLoc SemiLoc = Lex.getLoc();
+  if (consume(tgtok::semi)) {
+    PrintError(SemiLoc, "A class or def body should not end with a semicolon");
+    PrintNote("Semicolon ignored; remove to eliminate this error");    
+  }
+
   return false;
 }
 
@@ -2963,6 +3188,41 @@ bool TGParser::ParseIfBody(MultiClass *CurMultiClass, StringRef Kind) {
   return false;
 }
 
+/// ParseAssert - Parse an assert statement.
+///
+///   Assert ::= ASSERT condition , message ;
+bool TGParser::ParseAssert(MultiClass *CurMultiClass, Record *CurRec) {
+  assert(Lex.getCode() == tgtok::Assert && "Unknown tok");
+  Lex.Lex(); // Eat the 'assert' token.
+
+  SMLoc ConditionLoc = Lex.getLoc();
+  Init *Condition = ParseValue(CurRec);
+  if (!Condition)
+    return true;
+
+  if (!consume(tgtok::comma)) {
+    TokError("expected ',' in assert statement");
+    return true;
+  }
+
+  Init *Message = ParseValue(CurRec);
+  if (!Message)
+    return true;
+
+  if (!consume(tgtok::semi))
+    return TokError("expected ';'");
+
+  if (CurMultiClass) {
+    assert(false && "assert in multiclass not yet supported");
+  } else if (CurRec) {
+    CurRec->addAssertion(ConditionLoc, Condition, Message);
+  } else { // at top level
+    CheckAssert(ConditionLoc, Condition, Message);
+  }
+ 
+  return false;
+}
+
 /// ParseClass - Parse a tblgen class definition.
 ///
 ///   ClassInst ::= CLASS ID TemplateArgList? ObjectBody
@@ -3162,14 +3422,17 @@ bool TGParser::ParseMultiClass() {
     while (Lex.getCode() != tgtok::r_brace) {
       switch (Lex.getCode()) {
       default:
-        return TokError("expected 'let', 'def', 'defm', 'defvar', 'foreach' "
-                        "or 'if' in multiclass body");
-      case tgtok::Let:
+        return TokError("expected 'assert', 'def', 'defm', 'defvar', "
+                        "'foreach', 'if', or 'let' in multiclass body");
+      case tgtok::Assert:
+        return TokError("an assert statement in a multiclass is not yet supported");
+
       case tgtok::Def:
       case tgtok::Defm:
       case tgtok::Defvar:
       case tgtok::Foreach:
       case tgtok::If:
+      case tgtok::Let:
         if (ParseObject(CurMultiClass))
           return true;
         break;
@@ -3177,6 +3440,13 @@ bool TGParser::ParseMultiClass() {
     }
     Lex.Lex();  // eat the '}'.
 
+    // If we have a semicolon, print a gentle error.
+    SMLoc SemiLoc = Lex.getLoc();
+    if (consume(tgtok::semi)) {
+      PrintError(SemiLoc, "A multiclass body should not end with a semicolon");
+      PrintNote("Semicolon ignored; remove to eliminate this error");    
+    }
+
     PopLocalScope(MulticlassScope);
   }
 
@@ -3320,22 +3590,23 @@ bool TGParser::ParseDefm(MultiClass *CurMultiClass) {
 ///   Object ::= LETCommand Object
 ///   Object ::= Defset
 ///   Object ::= Defvar
+///   Object ::= Assert
 bool TGParser::ParseObject(MultiClass *MC) {
   switch (Lex.getCode()) {
   default:
-    return TokError("Expected class, def, defm, defset, multiclass, let, "
-                    "foreach or if");
-  case tgtok::Let:   return ParseTopLevelLet(MC);
-  case tgtok::Def:   return ParseDef(MC);
-  case tgtok::Foreach:   return ParseForeach(MC);
-  case tgtok::If:    return ParseIf(MC);
-  case tgtok::Defm:  return ParseDefm(MC);
+    return TokError(
+               "Expected assert, class, def, defm, defset, foreach, if, or let");
+  case tgtok::Assert:  return ParseAssert(MC, nullptr);
+  case tgtok::Def:     return ParseDef(MC);
+  case tgtok::Defm:    return ParseDefm(MC);
+  case tgtok::Defvar:  return ParseDefvar();
+  case tgtok::Foreach: return ParseForeach(MC);
+  case tgtok::If:      return ParseIf(MC);
+  case tgtok::Let:     return ParseTopLevelLet(MC);
   case tgtok::Defset:
     if (MC)
       return TokError("defset is not allowed inside multiclass");
     return ParseDefset();
-  case tgtok::Defvar:
-    return ParseDefvar();
   case tgtok::Class:
     if (MC)
       return TokError("class is not allowed inside multiclass");
@@ -3367,7 +3638,38 @@ bool TGParser::ParseFile() {
   if (Lex.getCode() == tgtok::Eof)
     return false;
 
-  return TokError("Unexpected input at top level");
+  return TokError("Unexpected token at top level");
+}
+
+// Check an assertion: Obtain the condition value and be sure it is true.
+// If not, print a nonfatal error along with the message.
+void TGParser::CheckAssert(SMLoc Loc, Init *Condition, Init *Message) {
+  auto *CondValue = dyn_cast_or_null<IntInit>(
+                        Condition->convertInitializerTo(IntRecTy::get()));
+  if (CondValue) {
+    if (!CondValue->getValue()) {
+      PrintError(Loc, "assertion failed");
+      if (auto *MessageInit = dyn_cast<StringInit>(Message))
+        PrintNote(MessageInit->getValue());
+      else
+        PrintNote("(assert message is not a string)");
+    }
+  } else {
+    PrintError(Loc, "assert condition must of type bit, bits, or int.");
+  }
+}
+
+// Check all record assertions: For each one, resolve the condition
+// and message, then call CheckAssert().
+void TGParser::CheckRecordAsserts(Record &Rec) {
+  RecordResolver R(Rec);
+  R.setFinal(true);
+
+  for (auto Assertion : Rec.getAssertions()) {
+    Init *Condition = std::get<1>(Assertion)->resolveReferences(R);
+    Init *Message = std::get<2>(Assertion)->resolveReferences(R);
+    CheckAssert(std::get<0>(Assertion), Condition, Message);
+  }
 }
 
 #if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
diff --git a/llvm/lib/TableGen/TGParser.h b/llvm/lib/TableGen/TGParser.h
index 07a4003219f5..578a56c9d01c 100644
--- a/llvm/lib/TableGen/TGParser.h
+++ b/llvm/lib/TableGen/TGParser.h
@@ -222,6 +222,7 @@ private:  // Parser methods.
   bool ParseForeach(MultiClass *CurMultiClass);
   bool ParseIf(MultiClass *CurMultiClass);
   bool ParseIfBody(MultiClass *CurMultiClass, StringRef Kind);
+  bool ParseAssert(MultiClass *CurMultiClass, Record *CurRec);
   bool ParseTopLevelLet(MultiClass *CurMultiClass);
   void ParseLetList(SmallVectorImpl<LetRecord> &Result);
 
@@ -254,6 +255,8 @@ private:  // Parser methods.
                        TypedInit *FirstItem = nullptr);
   RecTy *ParseType();
   Init *ParseOperation(Record *CurRec, RecTy *ItemType);
+  Init *ParseOperationSubstr(Record *CurRec, RecTy *ItemType);
+  Init *ParseOperationForEachFilter(Record *CurRec, RecTy *ItemType);
   Init *ParseOperationCond(Record *CurRec, RecTy *ItemType);
   RecTy *ParseOperatorType();
   Init *ParseObjectName(MultiClass *CurMultiClass);
@@ -261,6 +264,8 @@ private:  // Parser methods.
   MultiClass *ParseMultiClassID();
   bool ApplyLetStack(Record *CurRec);
   bool ApplyLetStack(RecordsEntry &Entry);
+  void CheckAssert(SMLoc Loc, Init *Condition, Init *Message);
+  void CheckRecordAsserts(Record &Rec);
 };
 
 } // end namespace llvm
diff --git a/llvm/lib/TableGen/TableGenBackendSkeleton.cpp b/llvm/lib/TableGen/TableGenBackendSkeleton.cpp
new file mode 100644
index 000000000000..4ce88e003e65
--- /dev/null
+++ b/llvm/lib/TableGen/TableGenBackendSkeleton.cpp
@@ -0,0 +1,64 @@
+//===- SkeletonEmitter.cpp - Skeleton TableGen backend          -*- C++ -*-===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+//
+// This Tablegen backend emits ...
+//
+//===----------------------------------------------------------------------===//
+
+#include "llvm/ADT/ArrayRef.h"
+#include "llvm/ADT/DenseMap.h"
+#include "llvm/ADT/StringExtras.h"
+#include "llvm/Support/Format.h"
+#include "llvm/Support/MemoryBuffer.h"
+#include "llvm/Support/SourceMgr.h"
+#include "llvm/TableGen/Error.h"
+#include "llvm/TableGen/Record.h"
+#include "llvm/TableGen/TableGenBackend.h"
+#include <algorithm>
+#include <set>
+#include <string>
+#include <vector>
+
+#define DEBUG_TYPE "skeleton-emitter"
+
+using namespace llvm;
+
+namespace {
+
+// Any helper data structures can be defined here. Some backends use
+// structs to collect information from the records.
+
+class SkeletonEmitter {
+private:
+  RecordKeeper &Records;
+
+public:
+  SkeletonEmitter(RecordKeeper &RK) : Records(RK) {}
+
+  void run(raw_ostream &OS);
+}; // emitter class
+
+} // anonymous namespace
+
+void SkeletonEmitter::run(raw_ostream &OS) {
+  emitSourceFileHeader("Skeleton data structures", OS);
+
+  (void)Records; // To suppress unused variable warning; remove on use.
+}
+
+namespace llvm {
+
+// The only thing that should be in the llvm namespace is the
+// emitter entry point function.
+
+void EmitSkeleton(RecordKeeper &RK, raw_ostream &OS) {
+  // Instantiate the emitter class and invoke run().
+  SkeletonEmitter(RK).run(OS);
+}
+
+} // namespace llvm