Subtarget support for parameterized register class information

Implement "checkFeatures" and emitting HW mode check code.

Differential Revision: https://reviews.llvm.org/D31959

llvm-svn: 313295

Author: Krzysztof Parzyszek

llvm/include/llvm/MC/MCSubtargetInfo.h

@@ -118,6 +118,10 @@ class MCSubtargetInfo {
   /// all feature bits implied by the flag.
   FeatureBitset ApplyFeatureFlag(StringRef FS);
 
+  /// Check whether the subtarget features are enabled/disabled as per
+  /// the provided string, ignoring all other features.
+  bool checkFeatures(StringRef FS) const;
+
   /// getSchedModelForCPU - Get the machine model of a CPU.
   ///
   const MCSchedModel &getSchedModelForCPU(StringRef CPU) const;

llvm/include/llvm/MC/SubtargetFeature.h

@@ -115,6 +115,9 @@ class SubtargetFeatures {
                                ArrayRef<SubtargetFeatureKV> CPUTable,
                                ArrayRef<SubtargetFeatureKV> FeatureTable);
 
+  /// Returns the vector of individual subtarget features.
+  const std::vector<std::string> &getFeatures() const { return Features; }
+
   /// Prints feature string.
   void print(raw_ostream &OS) const;
 

llvm/include/llvm/Target/TargetSubtargetInfo.h

@@ -110,6 +110,8 @@ class TargetSubtargetInfo : public MCSubtargetInfo {
     return nullptr;
   }
 
+  virtual unsigned getHwMode() const { return 0; }
+
   /// Target can subclass this hook to select a different DAG scheduler.
   virtual RegisterScheduler::FunctionPassCtor
       getDAGScheduler(CodeGenOpt::Level) const {

llvm/lib/MC/MCSubtargetInfo.cpp

@@ -75,6 +75,18 @@ FeatureBitset MCSubtargetInfo::ApplyFeatureFlag(StringRef FS) {
   return FeatureBits;
 }
 
+bool MCSubtargetInfo::checkFeatures(StringRef FS) const {
+  SubtargetFeatures T(FS);
+  FeatureBitset Set, All;
+  for (std::string F : T.getFeatures()) {
+    SubtargetFeatures::ApplyFeatureFlag(Set, F, ProcFeatures);
+    if (F[0] == '-')
+      F[0] = '+';
+    SubtargetFeatures::ApplyFeatureFlag(All, F, ProcFeatures);
+  }
+  return (FeatureBits & All) == Set;
+}
+
 const MCSchedModel &MCSubtargetInfo::getSchedModelForCPU(StringRef CPU) const {
   assert(ProcSchedModels && "Processor machine model not available!");
 

llvm/utils/TableGen/SubtargetEmitter.cpp

@@ -68,6 +68,7 @@ class SubtargetEmitter {
     }
   };
 
+  const CodeGenTarget &TGT;
   RecordKeeper &Records;
   CodeGenSchedModels &SchedModels;
   std::string Target;
@@ -106,12 +107,14 @@ class SubtargetEmitter {
   void EmitProcessorLookup(raw_ostream &OS);
   void EmitSchedModelHelpers(const std::string &ClassName, raw_ostream &OS);
   void EmitSchedModel(raw_ostream &OS);
+  void EmitHwModeCheck(const std::string &ClassName, raw_ostream &OS);
   void ParseFeaturesFunction(raw_ostream &OS, unsigned NumFeatures,
                              unsigned NumProcs);
 
 public:
-  SubtargetEmitter(RecordKeeper &R, CodeGenTarget &TGT):
-    Records(R), SchedModels(TGT.getSchedModels()), Target(TGT.getName()) {}
+  SubtargetEmitter(RecordKeeper &R, CodeGenTarget &TGT)
+    : TGT(TGT), Records(R), SchedModels(TGT.getSchedModels()),
+      Target(TGT.getName()) {}
 
   void run(raw_ostream &o);
 };
@@ -1329,6 +1332,22 @@ void SubtargetEmitter::EmitSchedModelHelpers(const std::string &ClassName,
      << "} // " << ClassName << "::resolveSchedClass\n";
 }
 
+void SubtargetEmitter::EmitHwModeCheck(const std::string &ClassName,
+                                       raw_ostream &OS) {
+  const CodeGenHwModes &CGH = TGT.getHwModes();
+  assert(CGH.getNumModeIds() > 0);
+  if (CGH.getNumModeIds() == 1)
+    return;
+
+  OS << "unsigned " << ClassName << "::getHwMode() const {\n";
+  for (unsigned M = 1, NumModes = CGH.getNumModeIds(); M != NumModes; ++M) {
+    const HwMode &HM = CGH.getMode(M);
+    OS << "  if (checkFeatures(\"" << HM.Features
+       << "\")) return " << M << ";\n";
+  }
+  OS << "  return 0;\n}\n";
+}
+
 //
 // ParseFeaturesFunction - Produces a subtarget specific function for parsing
 // the subtarget features string.
@@ -1462,9 +1481,11 @@ void SubtargetEmitter::run(raw_ostream &OS) {
      << " const MachineInstr *DefMI,"
      << " const TargetSchedModel *SchedModel) const override;\n"
      << "  DFAPacketizer *createDFAPacketizer(const InstrItineraryData *IID)"
-     << " const;\n"
-     << "};\n";
-  OS << "} // end namespace llvm\n\n";
+     << " const;\n";
+  if (TGT.getHwModes().getNumModeIds() > 1)
+    OS << "  unsigned getHwMode() const override;\n";
+  OS << "};\n"
+     << "} // end namespace llvm\n\n";
 
   OS << "#endif // GET_SUBTARGETINFO_HEADER\n\n";
 
@@ -1515,6 +1536,7 @@ void SubtargetEmitter::run(raw_ostream &OS) {
   OS << ") {}\n\n";
 
   EmitSchedModelHelpers(ClassName, OS);
+  EmitHwModeCheck(ClassName, OS);
 
   OS << "} // end namespace llvm\n\n";