[TableGen] Add const variants of accessors for backend

Split RecordKeeper `getAllDerivedDefinitions` family of functions into
two variants: (a) non-const ones that return vectors of `Record *` and
(b) const ones, that return vectors of `const Record *`.

This will help gradual migration of backend to use `const RecordKeeper`
and by implication change code to work with const pointers.

Author: jurahul

clang/utils/TableGen/ClangAttrEmitter.cpp

@@ -189,7 +189,7 @@ static StringRef NormalizeGNUAttrSpelling(StringRef AttrSpelling) {
 
 typedef std::vector<std::pair<std::string, const Record *>> ParsedAttrMap;
 
-static ParsedAttrMap getParsedAttrList(const RecordKeeper &Records,
+static ParsedAttrMap getParsedAttrList(RecordKeeper &Records,
                                        ParsedAttrMap *Dupes = nullptr,
                                        bool SemaOnly = true) {
   std::vector<Record *> Attrs = Records.getAllDerivedDefinitions("Attr");
@@ -4344,7 +4344,7 @@ static void GenerateAppertainsTo(const Record &Attr, raw_ostream &OS) {
 // written into OS and the checks for merging declaration attributes are
 // written into MergeOS.
 static void GenerateMutualExclusionsChecks(const Record &Attr,
-                                           const RecordKeeper &Records,
+                                           RecordKeeper &Records,
                                            raw_ostream &OS,
                                            raw_ostream &MergeDeclOS,
                                            raw_ostream &MergeStmtOS) {

clang/utils/TableGen/ClangSyntaxEmitter.cpp

@@ -41,7 +41,7 @@ using llvm::formatv;
 // stable and useful way, where abstract Node subclasses correspond to ranges.
 class Hierarchy {
 public:
-  Hierarchy(const llvm::RecordKeeper &Records) {
+  Hierarchy(llvm::RecordKeeper &Records) {
     for (llvm::Record *T : Records.getAllDerivedDefinitions("NodeType"))
       add(T);
     for (llvm::Record *Derived : Records.getAllDerivedDefinitions("NodeType"))

llvm/include/llvm/TableGen/DirectiveEmitter.h

@@ -15,8 +15,7 @@ namespace llvm {
 // DirectiveBase.td and provides helper methods for accessing it.
 class DirectiveLanguage {
 public:
-  explicit DirectiveLanguage(const llvm::RecordKeeper &Records)
-      : Records(Records) {
+  explicit DirectiveLanguage(llvm::RecordKeeper &Records) : Records(Records) {
     const auto &DirectiveLanguages = getDirectiveLanguages();
     Def = DirectiveLanguages[0];
   }
@@ -71,7 +70,7 @@ class DirectiveLanguage {
 
 private:
   const llvm::Record *Def;
-  const llvm::RecordKeeper &Records;
+  llvm::RecordKeeper &Records;
 
   std::vector<Record *> getDirectiveLanguages() const {
     return Records.getAllDerivedDefinitions("DirectiveLanguage");

llvm/include/llvm/TableGen/Record.h

@@ -2057,19 +2057,28 @@ class RecordKeeper {
   //===--------------------------------------------------------------------===//
   // High-level helper methods, useful for tablegen backends.
 
+  // Non-const methods return std::vector<Record *> by value or reference.
+  // Const methods return std::vector<const Record *> by value or reference.
+
   /// Get all the concrete records that inherit from the one specified
   /// class. The class must be defined.
-  std::vector<Record *> getAllDerivedDefinitions(StringRef ClassName) const;
+  const std::vector<const Record *> &
+  getAllDerivedDefinitions(StringRef ClassName) const;
+  const std::vector<Record *> &getAllDerivedDefinitions(StringRef ClassName);
 
   /// Get all the concrete records that inherit from all the specified
   /// classes. The classes must be defined.
-  std::vector<Record *> getAllDerivedDefinitions(
-      ArrayRef<StringRef> ClassNames) const;
+  std::vector<const Record *>
+  getAllDerivedDefinitions(ArrayRef<StringRef> ClassNames) const;
+  std::vector<Record *>
+  getAllDerivedDefinitions(ArrayRef<StringRef> ClassNames);
 
   /// Get all the concrete records that inherit from specified class, if the
   /// class is defined. Returns an empty vector if the class is not defined.
-  std::vector<Record *>
+  const std::vector<const Record *> &
   getAllDerivedDefinitionsIfDefined(StringRef ClassName) const;
+  const std::vector<Record *> &
+  getAllDerivedDefinitionsIfDefined(StringRef ClassName);
 
   void dump() const;
 
@@ -2079,9 +2088,24 @@ class RecordKeeper {
   RecordKeeper &operator=(RecordKeeper &&) = delete;
   RecordKeeper &operator=(const RecordKeeper &) = delete;
 
+  // Helper template functions for backend accessors.
+  template <typename VecTy>
+  const VecTy &
+  getAllDerivedDefinitionsImpl(StringRef ClassName,
+                               std::map<std::string, VecTy> &Cache) const;
+
+  template <typename VecTy>
+  VecTy getAllDerivedDefinitionsImpl(ArrayRef<StringRef> ClassNames) const;
+
+  template <typename VecTy>
+  const VecTy &getAllDerivedDefinitionsIfDefinedImpl(
+      StringRef ClassName, std::map<std::string, VecTy> &Cache) const;
+
   std::string InputFilename;
   RecordMap Classes, Defs;
-  mutable StringMap<std::vector<Record *>> ClassRecordsMap;
+  mutable std::map<std::string, std::vector<const Record *>>
+      ClassRecordsMapConst;
+  mutable std::map<std::string, std::vector<Record *>> ClassRecordsMap;
   GlobalMap ExtraGlobals;
 
   // These members are for the phase timing feature. We need a timer group,

llvm/lib/TableGen/Record.cpp

@@ -3219,46 +3219,83 @@ void RecordKeeper::stopBackendTimer() {
   }
 }
 
-std::vector<Record *>
-RecordKeeper::getAllDerivedDefinitions(StringRef ClassName) const {
+template <typename VecTy>
+const VecTy &RecordKeeper::getAllDerivedDefinitionsImpl(
+    StringRef ClassName, std::map<std::string, VecTy> &Cache) const {
   // We cache the record vectors for single classes. Many backends request
   // the same vectors multiple times.
-  auto Pair = ClassRecordsMap.try_emplace(ClassName);
+  auto Pair = Cache.try_emplace(ClassName.str());
   if (Pair.second)
-    Pair.first->second = getAllDerivedDefinitions(ArrayRef(ClassName));
+    Pair.first->second =
+        getAllDerivedDefinitionsImpl<VecTy>(ArrayRef(ClassName));
 
   return Pair.first->second;
 }
 
-std::vector<Record *> RecordKeeper::getAllDerivedDefinitions(
+template <typename VecTy>
+VecTy RecordKeeper::getAllDerivedDefinitionsImpl(
     ArrayRef<StringRef> ClassNames) const {
-  SmallVector<Record *, 2> ClassRecs;
-  std::vector<Record *> Defs;
+  SmallVector<const Record *, 2> ClassRecs;
+  VecTy Defs;
 
   assert(ClassNames.size() > 0 && "At least one class must be passed.");
   for (const auto &ClassName : ClassNames) {
-    Record *Class = getClass(ClassName);
+    const 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);
-                          }))
+          return OneDef.second->isSubClassOf(Class);
+        }))
       Defs.push_back(OneDef.second.get());
   }
-
   llvm::sort(Defs, LessRecord());
-
   return Defs;
 }
 
+template <typename VecTy>
+const VecTy &RecordKeeper::getAllDerivedDefinitionsIfDefinedImpl(
+    StringRef ClassName, std::map<std::string, VecTy> &Cache) const {
+  return getClass(ClassName)
+             ? getAllDerivedDefinitionsImpl<VecTy>(ClassName, Cache)
+             : Cache[""];
+}
+
+const std::vector<const Record *> &
+RecordKeeper::getAllDerivedDefinitions(StringRef ClassName) const {
+  return getAllDerivedDefinitionsImpl<std::vector<const Record *>>(
+      ClassName, ClassRecordsMapConst);
+}
+
+const std::vector<Record *> &
+RecordKeeper::getAllDerivedDefinitions(StringRef ClassName) {
+  return getAllDerivedDefinitionsImpl<std::vector<Record *>>(ClassName,
+                                                             ClassRecordsMap);
+}
+
+std::vector<const Record *>
+RecordKeeper::getAllDerivedDefinitions(ArrayRef<StringRef> ClassNames) const {
+  return getAllDerivedDefinitionsImpl<std::vector<const Record *>>(ClassNames);
+}
+
 std::vector<Record *>
+RecordKeeper::getAllDerivedDefinitions(ArrayRef<StringRef> ClassNames) {
+  return getAllDerivedDefinitionsImpl<std::vector<Record *>>(ClassNames);
+}
+
+const std::vector<const Record *> &
 RecordKeeper::getAllDerivedDefinitionsIfDefined(StringRef ClassName) const {
-  return getClass(ClassName) ? getAllDerivedDefinitions(ClassName)
-                             : std::vector<Record *>();
+  return getAllDerivedDefinitionsIfDefinedImpl<std::vector<const Record *>>(
+      ClassName, ClassRecordsMapConst);
+}
+
+const std::vector<Record *> &
+RecordKeeper::getAllDerivedDefinitionsIfDefined(StringRef ClassName) {
+  return getAllDerivedDefinitionsIfDefinedImpl<std::vector<Record *>>(
+      ClassName, ClassRecordsMap);
 }
 
 Init *MapResolver::resolve(Init *VarName) {

llvm/utils/TableGen/Basic/CodeGenIntrinsics.cpp

@@ -26,15 +26,13 @@ using namespace llvm;
 //===----------------------------------------------------------------------===//
 
 CodeGenIntrinsicTable::CodeGenIntrinsicTable(const RecordKeeper &RC) {
-  std::vector<Record *> IntrProperties =
-      RC.getAllDerivedDefinitions("IntrinsicProperty");
-
   std::vector<const Record *> DefaultProperties;
-  for (const Record *Rec : IntrProperties)
+  for (const Record *Rec : RC.getAllDerivedDefinitions("IntrinsicProperty"))
     if (Rec->getValueAsBit("IsDefault"))
       DefaultProperties.push_back(Rec);
 
-  std::vector<Record *> Defs = RC.getAllDerivedDefinitions("Intrinsic");
+  const std::vector<const Record *> &Defs =
+      RC.getAllDerivedDefinitions("Intrinsic");
   Intrinsics.reserve(Defs.size());
 
   for (const Record *Def : Defs)

llvm/utils/TableGen/Common/SubtargetFeatureInfo.cpp

@@ -21,7 +21,7 @@ LLVM_DUMP_METHOD void SubtargetFeatureInfo::dump() const {
 #endif
 
 std::vector<std::pair<Record *, SubtargetFeatureInfo>>
-SubtargetFeatureInfo::getAll(const RecordKeeper &Records) {
+SubtargetFeatureInfo::getAll(RecordKeeper &Records) {
   std::vector<std::pair<Record *, SubtargetFeatureInfo>> SubtargetFeatures;
   std::vector<Record *> AllPredicates =
       Records.getAllDerivedDefinitions("Predicate");

llvm/utils/TableGen/Common/SubtargetFeatureInfo.h

@@ -49,7 +49,7 @@ struct SubtargetFeatureInfo {
 
   void dump() const;
   static std::vector<std::pair<Record *, SubtargetFeatureInfo>>
-  getAll(const RecordKeeper &Records);
+  getAll(RecordKeeper &Records);
 
   /// Emit the subtarget feature flag definitions.
   ///

llvm/utils/TableGen/ExegesisEmitter.cpp

@@ -59,7 +59,7 @@ class ExegesisEmitter {
 };
 
 static std::map<llvm::StringRef, unsigned>
-collectPfmCounters(const RecordKeeper &Records) {
+collectPfmCounters(RecordKeeper &Records) {
   std::map<llvm::StringRef, unsigned> PfmCounterNameTable;
   const auto AddPfmCounterName = [&PfmCounterNameTable](
                                      const Record *PfmCounterDef) {

llvm/utils/TableGen/GlobalISelEmitter.cpp

@@ -335,7 +335,7 @@ class GlobalISelEmitter final : public GlobalISelMatchTableExecutorEmitter {
 private:
   std::string ClassName;
 
-  const RecordKeeper &RK;
+  RecordKeeper &RK;
   const CodeGenDAGPatterns CGP;
   const CodeGenTarget &Target;
   CodeGenRegBank &CGRegs;

llvm/utils/TableGen/SubtargetEmitter.cpp

@@ -1545,7 +1545,7 @@ void SubtargetEmitter::EmitSchedModel(raw_ostream &OS) {
   EmitProcessorModels(OS);
 }
 
-static void emitPredicateProlog(const RecordKeeper &Records, raw_ostream &OS) {
+static void emitPredicateProlog(RecordKeeper &Records, raw_ostream &OS) {
   std::string Buffer;
   raw_string_ostream Stream(Buffer);
 

llvm/utils/TableGen/TableGen.cpp

@@ -52,7 +52,7 @@ static void PrintEnums(RecordKeeper &Records, raw_ostream &OS) {
 static void PrintSets(const RecordKeeper &Records, raw_ostream &OS) {
   SetTheory Sets;
   Sets.addFieldExpander("Set", "Elements");
-  for (Record *Rec : Records.getAllDerivedDefinitions("Set")) {
+  for (const Record *Rec : Records.getAllDerivedDefinitions("Set")) {
     OS << Rec->getName() << " = [";
     const std::vector<Record *> *Elts = Sets.expand(Rec);
     assert(Elts && "Couldn't expand Set instance");

mlir/include/mlir/TableGen/GenInfo.h

@@ -21,8 +21,8 @@ class RecordKeeper;
 namespace mlir {
 
 /// Generator function to invoke.
-using GenFunction = std::function<bool(const llvm::RecordKeeper &recordKeeper,
-                                       raw_ostream &os)>;
+using GenFunction =
+    std::function<bool(llvm::RecordKeeper &recordKeeper, raw_ostream &os)>;
 
 /// Structure to group information about a generator (argument to invoke via
 /// mlir-tblgen, description, and generator function).
@@ -34,7 +34,7 @@ class GenInfo {
       : arg(arg), description(description), generator(std::move(generator)) {}
 
   /// Invokes the generator and returns whether the generator failed.
-  bool invoke(const llvm::RecordKeeper &recordKeeper, raw_ostream &os) const {
+  bool invoke(llvm::RecordKeeper &recordKeeper, raw_ostream &os) const {
     assert(generator && "Cannot call generator with null generator");
     return generator(recordKeeper, os);
   }