[TableGen] Change SubtargetFeatureInfo to use const Record pointers (#108013)

Change SubtargetFeatureInfo to use const Record pointers.

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/utils/TableGen/AsmMatcherEmitter.cpp

@@ -762,7 +762,7 @@ class AsmMatcherInfo {
   RegisterClassesTy RegisterClasses;
 
   /// Map of Predicate records to their subtarget information.
-  std::map<Record *, SubtargetFeatureInfo, LessRecordByID> SubtargetFeatures;
+  SubtargetFeatureInfoMap SubtargetFeatures;
 
   /// Map of AsmOperandClass records to their class information.
   std::map<const Record *, ClassInfo *> AsmOperandClasses;
@@ -1513,8 +1513,8 @@ void AsmMatcherInfo::buildOperandMatchInfo() {
 
 void AsmMatcherInfo::buildInfo() {
   // Build information about all of the AssemblerPredicates.
-  const std::vector<std::pair<Record *, SubtargetFeatureInfo>>
-      &SubtargetFeaturePairs = SubtargetFeatureInfo::getAll(Records);
+  SubtargetFeaturesInfoVec SubtargetFeaturePairs =
+      SubtargetFeatureInfo::getAll(Records);
   SubtargetFeatures.insert(SubtargetFeaturePairs.begin(),
                            SubtargetFeaturePairs.end());
 #ifndef NDEBUG
@@ -3226,9 +3226,9 @@ static void emitMatchClassKindNames(std::forward_list<ClassInfo> &Infos,
 }
 
 static std::string
-getNameForFeatureBitset(const std::vector<Record *> &FeatureBitset) {
+getNameForFeatureBitset(ArrayRef<const Record *> FeatureBitset) {
   std::string Name = "AMFBS";
-  for (const auto &Feature : FeatureBitset)
+  for (const Record *Feature : FeatureBitset)
     Name += ("_" + Feature->getName()).str();
   return Name;
 }
@@ -3451,7 +3451,7 @@ void AsmMatcherEmitter::run(raw_ostream &OS) {
   StringTable.EmitString(OS);
   OS << ";\n\n";
 
-  std::vector<std::vector<Record *>> FeatureBitsets;
+  std::vector<std::vector<const Record *>> FeatureBitsets;
   for (const auto &MI : Info.Matchables) {
     if (MI->RequiredFeatures.empty())
       continue;
@@ -3460,8 +3460,8 @@ void AsmMatcherEmitter::run(raw_ostream &OS) {
       FeatureBitsets.back().push_back(MI->RequiredFeatures[I]->TheDef);
   }
 
-  llvm::sort(FeatureBitsets, [&](const std::vector<Record *> &A,
-                                 const std::vector<Record *> &B) {
+  llvm::sort(FeatureBitsets, [&](const std::vector<const Record *> &A,
+                                 const std::vector<const Record *> &B) {
     if (A.size() < B.size())
       return true;
     if (A.size() > B.size())

llvm/utils/TableGen/Common/SubtargetFeatureInfo.cpp

@@ -20,12 +20,10 @@ LLVM_DUMP_METHOD void SubtargetFeatureInfo::dump() const {
 }
 #endif
 
-std::vector<std::pair<Record *, SubtargetFeatureInfo>>
-SubtargetFeatureInfo::getAll(RecordKeeper &Records) {
-  std::vector<std::pair<Record *, SubtargetFeatureInfo>> SubtargetFeatures;
-  std::vector<Record *> AllPredicates =
-      Records.getAllDerivedDefinitions("Predicate");
-  for (Record *Pred : AllPredicates) {
+SubtargetFeaturesInfoVec
+SubtargetFeatureInfo::getAll(const RecordKeeper &Records) {
+  SubtargetFeaturesInfoVec SubtargetFeatures;
+  for (const Record *Pred : Records.getAllDerivedDefinitions("Predicate")) {
     // Ignore predicates that are not intended for the assembler.
     //
     // The "AssemblerMatcherPredicate" string should be promoted to an argument

llvm/utils/TableGen/Common/SubtargetFeatureInfo.h

@@ -19,18 +19,20 @@
 namespace llvm {
 struct SubtargetFeatureInfo;
 using SubtargetFeatureInfoMap =
-    std::map<Record *, SubtargetFeatureInfo, LessRecordByID>;
+    std::map<const Record *, SubtargetFeatureInfo, LessRecordByID>;
+using SubtargetFeaturesInfoVec =
+    std::vector<std::pair<const Record *, SubtargetFeatureInfo>>;
 
 /// Helper class for storing information on a subtarget feature which
 /// participates in instruction matching.
 struct SubtargetFeatureInfo {
   /// The predicate record for this feature.
-  Record *TheDef;
+  const Record *TheDef;
 
   /// An unique index assigned to represent this feature.
   uint64_t Index;
 
-  SubtargetFeatureInfo(Record *D, uint64_t Idx) : TheDef(D), Index(Idx) {}
+  SubtargetFeatureInfo(const Record *D, uint64_t Idx) : TheDef(D), Index(Idx) {}
 
   /// The name of the enumerated constant identifying this feature.
   std::string getEnumName() const {
@@ -48,8 +50,8 @@ struct SubtargetFeatureInfo {
   }
 
   void dump() const;
-  static std::vector<std::pair<Record *, SubtargetFeatureInfo>>
-  getAll(RecordKeeper &Records);
+
+  static SubtargetFeaturesInfoVec getAll(const RecordKeeper &Records);
 
   /// Emit the subtarget feature flag definitions.
   ///

llvm/utils/TableGen/InstrInfoEmitter.cpp

@@ -721,17 +721,17 @@ void InstrInfoEmitter::emitMCIIHelperMethods(raw_ostream &OS,
 }
 
 static std::string
-getNameForFeatureBitset(const std::vector<Record *> &FeatureBitset) {
+getNameForFeatureBitset(ArrayRef<const Record *> FeatureBitset) {
   std::string Name = "CEFBS";
-  for (const auto &Feature : FeatureBitset)
+  for (const Record *Feature : FeatureBitset)
     Name += ("_" + Feature->getName()).str();
   return Name;
 }
 
 void InstrInfoEmitter::emitFeatureVerifier(raw_ostream &OS,
                                            const CodeGenTarget &Target) {
   const auto &All = SubtargetFeatureInfo::getAll(Records);
-  std::map<Record *, SubtargetFeatureInfo, LessRecordByID> SubtargetFeatures;
+  SubtargetFeatureInfoMap SubtargetFeatures;
   SubtargetFeatures.insert(All.begin(), All.end());
 
   OS << "#if (defined(ENABLE_INSTR_PREDICATE_VERIFIER) && !defined(NDEBUG)) "
@@ -752,18 +752,19 @@ void InstrInfoEmitter::emitFeatureVerifier(raw_ostream &OS,
   SubtargetFeatureInfo::emitComputeAssemblerAvailableFeatures(
       Target.getName(), "", "computeAvailableFeatures", SubtargetFeatures, OS);
 
-  std::vector<std::vector<Record *>> FeatureBitsets;
+  std::vector<std::vector<const Record *>> FeatureBitsets;
   for (const CodeGenInstruction *Inst : Target.getInstructionsByEnumValue()) {
     FeatureBitsets.emplace_back();
-    for (Record *Predicate : Inst->TheDef->getValueAsListOfDefs("Predicates")) {
+    for (const Record *Predicate :
+         Inst->TheDef->getValueAsListOfDefs("Predicates")) {
       const auto &I = SubtargetFeatures.find(Predicate);
       if (I != SubtargetFeatures.end())
         FeatureBitsets.back().push_back(I->second.TheDef);
     }
   }
 
-  llvm::sort(FeatureBitsets, [&](const std::vector<Record *> &A,
-                                 const std::vector<Record *> &B) {
+  llvm::sort(FeatureBitsets, [&](const std::vector<const Record *> &A,
+                                 const std::vector<const Record *> &B) {
     if (A.size() < B.size())
       return true;
     if (A.size() > B.size())
@@ -806,7 +807,8 @@ void InstrInfoEmitter::emitFeatureVerifier(raw_ostream &OS,
   for (const CodeGenInstruction *Inst : Target.getInstructionsByEnumValue()) {
     OS << "    CEFBS";
     unsigned NumPredicates = 0;
-    for (Record *Predicate : Inst->TheDef->getValueAsListOfDefs("Predicates")) {
+    for (const Record *Predicate :
+         Inst->TheDef->getValueAsListOfDefs("Predicates")) {
       const auto &I = SubtargetFeatures.find(Predicate);
       if (I != SubtargetFeatures.end()) {
         OS << '_' << I->second.TheDef->getName();
@@ -890,7 +892,8 @@ void InstrInfoEmitter::emitFeatureVerifier(raw_ostream &OS,
 void InstrInfoEmitter::emitTIIHelperMethods(raw_ostream &OS,
                                             StringRef TargetName,
                                             bool ExpandDefinition) {
-  RecVec TIIPredicates = Records.getAllDerivedDefinitions("TIIPredicate");
+  ArrayRef<const Record *> TIIPredicates =
+      Records.getAllDerivedDefinitions("TIIPredicate");
   if (TIIPredicates.empty())
     return;