[TableGen] Delete non-const overloads of getAllDerivedDefinitions (#110990)

Now that all TableGen backends have transitioned to const versions of
these functions, we do not need the non-const versions anymore.

This is a part of effort to have better const correctness in TableGen
backends:


https://discourse.llvm.org/t/psa-planned-changes-to-tablegen-getallderiveddefinitions-api-potential-downstream-breakages/81089

Author: jurahul

llvm/include/llvm/TableGen/Record.h

@@ -2060,28 +2060,19 @@ 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
-  // ArrayRef<const Record *>.
-
   /// Get all the concrete records that inherit from the one specified
   /// class. The class must be defined.
   ArrayRef<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<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.
   ArrayRef<const Record *>
   getAllDerivedDefinitionsIfDefined(StringRef ClassName) const;
-  const std::vector<Record *> &
-  getAllDerivedDefinitionsIfDefined(StringRef ClassName);
 
   void dump() const;
 
@@ -2093,24 +2084,9 @@ 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 std::map<std::string, std::vector<const Record *>>
-      ClassRecordsMapConst;
-  mutable std::map<std::string, std::vector<Record *>> ClassRecordsMap;
+  mutable std::map<std::string, std::vector<const Record *>> Cache;
   GlobalMap ExtraGlobals;
 
   // TODO: Move timing related code out of RecordKeeper.

llvm/lib/TableGen/Record.cpp

@@ -3275,24 +3275,20 @@ void RecordKeeper::stopBackendTimer() {
   }
 }
 
-template <typename VecTy>
-const VecTy &RecordKeeper::getAllDerivedDefinitionsImpl(
-    StringRef ClassName, std::map<std::string, VecTy> &Cache) const {
+ArrayRef<const Record *>
+RecordKeeper::getAllDerivedDefinitions(StringRef ClassName) const {
   // We cache the record vectors for single classes. Many backends request
   // the same vectors multiple times.
-  auto Pair = Cache.try_emplace(ClassName.str());
-  if (Pair.second)
-    Pair.first->second =
-        getAllDerivedDefinitionsImpl<VecTy>(ArrayRef(ClassName));
-
-  return Pair.first->second;
+  auto [Iter, Inserted] = Cache.try_emplace(ClassName.str());
+  if (Inserted)
+    Iter->second = getAllDerivedDefinitions(ArrayRef(ClassName));
+  return Iter->second;
 }
 
-template <typename VecTy>
-VecTy RecordKeeper::getAllDerivedDefinitionsImpl(
-    ArrayRef<StringRef> ClassNames) const {
+std::vector<const Record *>
+RecordKeeper::getAllDerivedDefinitions(ArrayRef<StringRef> ClassNames) const {
   SmallVector<const Record *, 2> ClassRecs;
-  VecTy Defs;
+  std::vector<const Record *> Defs;
 
   assert(ClassNames.size() > 0 && "At least one class must be passed.");
   for (const auto &ClassName : ClassNames) {
@@ -3312,46 +3308,11 @@ VecTy RecordKeeper::getAllDerivedDefinitionsImpl(
   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[""];
-}
-
-ArrayRef<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);
-}
-
 ArrayRef<const Record *>
 RecordKeeper::getAllDerivedDefinitionsIfDefined(StringRef ClassName) const {
-  return getAllDerivedDefinitionsIfDefinedImpl<std::vector<const Record *>>(
-      ClassName, ClassRecordsMapConst);
-}
-
-const std::vector<Record *> &
-RecordKeeper::getAllDerivedDefinitionsIfDefined(StringRef ClassName) {
-  return getAllDerivedDefinitionsIfDefinedImpl<std::vector<Record *>>(
-      ClassName, ClassRecordsMap);
+  if (getClass(ClassName))
+    return getAllDerivedDefinitions(ClassName);
+  return Cache[""];
 }
 
 void RecordKeeper::dumpAllocationStats(raw_ostream &OS) const {