utils/TableGen/SubtargetEmitter.cpp

//===- SubtargetEmitter.cpp - Generate subtarget enumerations -------------===//
//
//                     The LLVM Compiler Infrastructure
//
// This file was developed by James M. Laskey and is distributed under
// the University of Illinois Open Source License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This tablegen backend emits subtarget enumerations.
//
//===----------------------------------------------------------------------===//

#include "SubtargetEmitter.h"
#include "CodeGenTarget.h"
#include "Record.h"
#include "llvm/ADT/StringExtras.h"
#include "llvm/Support/Debug.h"
#include <algorithm>
using namespace llvm;

//
// Record sort by name function.
//
struct LessRecord {
  bool operator()(const Record *Rec1, const Record *Rec2) const {
    return Rec1->getName() < Rec2->getName();
  }
};

//
// Record sort by field "Name" function.
//
struct LessRecordFieldName {
  bool operator()(const Record *Rec1, const Record *Rec2) const {
    return Rec1->getValueAsString("Name") < Rec2->getValueAsString("Name");
  }
};

//
// Enumeration - Emit the specified class as an enumeration.
//
void SubtargetEmitter::Enumeration(std::ostream &OS,
                                   const char *ClassName,
                                   bool isBits) {
  // Get all records of class and sort
  std::vector<Record*> DefList = Records.getAllDerivedDefinitions(ClassName);
  sort(DefList.begin(), DefList.end(), LessRecord());

  // Open enumeration
  OS << "enum {\n";
  
  // For each record
  for (unsigned i = 0, N = DefList.size(); i < N;) {
    // Next record
    Record *Def = DefList[i];
    
    // Get and emit name
    std::string Name = Def->getName();
    OS << "  " << Name;
    
    // If bit flags then emit expression (1 << i)
    if (isBits)  OS << " = " << " 1 << " << i;

    // Depending on if more in the list emit comma
    if (++i < N) OS << ",";
    
    OS << "\n";
  }
  
  // Close enumeration
  OS << "};\n";
}

//
// FeatureKeyValues - Emit data of all the subtarget features.  Used by command
// line.
//
void SubtargetEmitter::FeatureKeyValues(std::ostream &OS) {
  // Gather and sort all the features
  std::vector<Record*> FeatureList =
                           Records.getAllDerivedDefinitions("SubtargetFeature");
  sort(FeatureList.begin(), FeatureList.end(), LessRecord());

  // Begin feature table
  OS << "// Sorted (by key) array of values for CPU features.\n"
     << "static llvm::SubtargetFeatureKV FeatureKV[] = {\n";
  
  // For each feature
  for (unsigned i = 0, N = FeatureList.size(); i < N;) {
    // Next feature
    Record *Feature = FeatureList[i];

    std::string Name = Feature->getName();
    std::string CommandLineName = Feature->getValueAsString("Name");
    std::string Desc = Feature->getValueAsString("Desc");
    
    // Emit as { "feature", "decription", feactureEnum }
    OS << "  { "
       << "\"" << CommandLineName << "\", "
       << "\"" << Desc << "\", "
       << Name
       << " }";
    
    // Depending on if more in the list emit comma
    if (++i < N) OS << ",";
    
    OS << "\n";
  }
  
  // End feature table
  OS << "};\n";

  // Emit size of table
  OS<<"\nenum {\n";
  OS<<"  FeatureKVSize = sizeof(FeatureKV)/sizeof(llvm::SubtargetFeatureKV)\n";
  OS<<"};\n";
}

//
// CPUKeyValues - Emit data of all the subtarget processors.  Used by command
// line.
//
void SubtargetEmitter::CPUKeyValues(std::ostream &OS) {
  // Gather and sort processor information
  std::vector<Record*> ProcessorList =
                          Records.getAllDerivedDefinitions("Processor");
  sort(ProcessorList.begin(), ProcessorList.end(), LessRecordFieldName());

  // Begin processor table
  OS << "// Sorted (by key) array of values for CPU subtype.\n"
     << "static const llvm::SubtargetFeatureKV SubTypeKV[] = {\n";
     
  // For each processor
  for (unsigned i = 0, N = ProcessorList.size(); i < N;) {
    // Next processor
    Record *Processor = ProcessorList[i];

    std::string Name = Processor->getValueAsString("Name");
    std::vector<Record*> FeatureList = Processor->getValueAsListDef("Features");
    
    // Emit as { "cpu", "description", f1 | f2 | ... fn },
    OS << "  { "
       << "\"" << Name << "\", "
       << "\"Select the " << Name << " processor\", ";
    
    if (FeatureList.empty()) {
      OS << "0";
    } else {
      for (unsigned j = 0, M = FeatureList.size(); j < M;) {
        Record *Feature = FeatureList[j];
        std::string Name = Feature->getName();
        OS << Name;
        if (++j < M) OS << " | ";
      }
    }
    
    OS << " }";
    
    // Depending on if more in the list emit comma
    if (++i < N) OS << ",";
    
    OS << "\n";
  }
  
  // End processor table
  OS << "};\n";

  // Emit size of table
  OS<<"\nenum {\n";
  OS<<"  SubTypeKVSize = sizeof(SubTypeKV)/sizeof(llvm::SubtargetFeatureKV)\n";
  OS<<"};\n";
}

//
// CollectAllItinClasses - Gathers and enumerates all the itinerary classes.
// Returns itinerary class count.
//
unsigned SubtargetEmitter::CollectAllItinClasses(std::map<std::string, unsigned>
                                                              &ItinClassesMap) {
  // Gather and sort all itinerary classes
  std::vector<Record*> ItinClassList =
                            Records.getAllDerivedDefinitions("InstrItinClass");
  sort(ItinClassList.begin(), ItinClassList.end(), LessRecord());

  // For each itinerary class
  unsigned N = ItinClassList.size();
  for (unsigned i = 0; i < N; i++) {
    // Next itinerary class
    Record *ItinClass = ItinClassList[i];
    // Get name of itinerary class
    std::string Name = ItinClass->getName();
    // Assign itinerary class a unique number
    ItinClassesMap[Name] = i;
  }
  
  // Return itinerary class count
  return N;
}

//
// FormItineraryString - Compose a string containing the data initialization
// for the specified itinerary.  N is the number of stages.
//
void SubtargetEmitter::FormItineraryString(Record *ItinData,
                                           std::string &ItinString,
                                           unsigned &NStages) {
  // Get states list
  std::vector<Record*> StageList = ItinData->getValueAsListDef("Stages");

  // For each stage
  unsigned N = NStages = StageList.size();
  for (unsigned i = 0; i < N; i++) {
    // Next stage
    Record *Stage = StageList[i];
  
    // Form string as ,{ cycles, u1 | u2 | ... | un }
    int Cycles = Stage->getValueAsInt("Cycles");
    ItinString += "  ,{ " + itostr(Cycles) + ", ";
    
    // Get unit list
    std::vector<Record*> UnitList = Stage->getValueAsListDef("Units");
    
    // For each unit
    for (unsigned j = 0, M = UnitList.size(); j < M;) {
      // Next unit
      Record *Unit = UnitList[j];
      
      // Add name and bitwise or
      ItinString += Unit->getName();
      if (++j < M) ItinString += " | ";
    }
    
    // Close off stage
    ItinString += " }";
  }
}

//
// EmitStageData - Generate unique itinerary stages.  Record itineraries for 
// processors.
//
void SubtargetEmitter::EmitStageData(std::ostream &OS,
       unsigned NItinClasses,
       std::map<std::string, unsigned> &ItinClassesMap, 
       std::vector<std::vector<InstrItinerary> > &ProcList) {
  // Gather processor iteraries
  std::vector<Record*> ProcItinList =
                       Records.getAllDerivedDefinitions("ProcessorItineraries");
  
  // If just no itinerary then don't bother
  if (ProcItinList.size() < 2) return;

  // Begin stages table
  OS << "static llvm::InstrStage Stages[] = {\n"
        "  { 0, 0 } // No itinerary\n";
        
  unsigned ItinEnum = 1;
  std::map<std::string, unsigned> ItinMap;
  for (unsigned i = 0, N = ProcItinList.size(); i < N; i++) {
    // Next record
    Record *Proc = ProcItinList[i];
    
    // Get processor itinerary name
    std::string Name = Proc->getName();
    
    // Skip default
    if (Name == "NoItineraries") continue;
    
    // Create and expand processor itinerary to cover all itinerary classes
    std::vector<InstrItinerary> ItinList;
    ItinList.resize(NItinClasses);
    
    // Get itinerary data list
    std::vector<Record*> ItinDataList = Proc->getValueAsListDef("IID");
    
    // For each itinerary data
    for (unsigned j = 0, M = ItinDataList.size(); j < M; j++) {
      // Next itinerary data
      Record *ItinData = ItinDataList[j];
      
      // Get string and stage count
      std::string ItinString;
      unsigned NStages;
      FormItineraryString(ItinData, ItinString, NStages);

      // Check to see if it already exists
      unsigned Find = ItinMap[ItinString];
      
      // If new itinerary
      if (Find == 0) {
        // Emit as ,{ cycles, u1 | u2 | ... | un } // index
        OS << ItinString << " // " << ItinEnum << "\n";
        ItinMap[ItinString] = Find = ItinEnum++;
      }
      
      // Set up itinerary as location and location + stage count
      InstrItinerary Intinerary = { Find, Find + NStages };

      // Locate where to inject into processor itinerary table
      std::string Name = ItinData->getValueAsDef("TheClass")->getName();
      Find = ItinClassesMap[Name];
      
      // Inject - empty slots will be 0, 0
      ItinList[Find] = Intinerary;
    }
    
    // Add process itinerary to list
    ProcList.push_back(ItinList);
  }
  
  // End stages table
  OS << "};\n";
}

//
// EmitProcessData - Generate data for processor itineraries.
//
void SubtargetEmitter::EmitProcessData(std::ostream &OS,
      std::vector<std::vector<InstrItinerary> > &ProcList) {
  // Get an iterator for processor itinerary stages
  std::vector<std::vector<InstrItinerary> >::iterator
      ProcListIter = ProcList.begin();
  
  // For each processor itinerary
  std::vector<Record*> Itins =
                       Records.getAllDerivedDefinitions("ProcessorItineraries");
  for (unsigned i = 0, N = Itins.size(); i < N; i++) {
    // Next record
    Record *Itin = Itins[i];

    // Get processor itinerary name
    std::string Name = Itin->getName();
    
    // Skip default
    if (Name == "NoItineraries") continue;

    // Begin processor itinerary table
    OS << "\n";
    OS << "static llvm::InstrItinerary " << Name << "[] = {\n";
    
    // For each itinerary class
    std::vector<InstrItinerary> &ItinList = *ProcListIter++;
    unsigned ItinIndex = 0;
    for (unsigned j = 0, M = ItinList.size(); j < M;) {
      InstrItinerary &Intinerary = ItinList[j];
      
      // Emit in the form of { first, last } // index
      if (Intinerary.First == 0) {
        OS << "  { 0, 0 }";
      } else {
        OS << "  { " << Intinerary.First << ", " << Intinerary.Last << " }";
      }
      
      // If more in list add comma
      if (++j < M) OS << ",";
      
      OS << " // " << (j - 1) << "\n";
    }
    
    // End processor itinerary table
    OS << "};\n";
  }
}

//
// EmitData - Emits all stages and itineries, folding common patterns.
//
void SubtargetEmitter::EmitData(std::ostream &OS) {
  std::map<std::string, unsigned> ItinClassesMap;
  std::vector<std::vector<InstrItinerary> > ProcList;
  
  // Enumerate all the itinerary classes
  unsigned NItinClasses = CollectAllItinClasses(ItinClassesMap);
  // Emit the stage data
  EmitStageData(OS, NItinClasses, ItinClassesMap, ProcList);
  // Emit the processor itinerary data
  EmitProcessData(OS, ProcList);
}

//
// ParseFeaturesFunction - Produces a subtarget specific function for parsing
// the subtarget features string.
//
void SubtargetEmitter::ParseFeaturesFunction(std::ostream &OS) {
  std::vector<Record*> Features =
                       Records.getAllDerivedDefinitions("SubtargetFeature");
  sort(Features.begin(), Features.end(), LessRecord());

  OS << "// ParseSubtargetFeatures - Parses features string setting specified\n" 
        "// subtarget options.\n" 
        "void llvm::";
  OS << Target;
  OS << "Subtarget::ParseSubtargetFeatures(const std::string &FS,\n"
        "                                  const std::string &CPU) {\n"
        "  SubtargetFeatures Features(FS);\n"
        "  Features.setCPUIfNone(CPU);\n"
        "  uint32_t Bits =  Features.getBits(SubTypeKV, SubTypeKVSize,\n"
        "                                    FeatureKV, FeatureKVSize);\n";
        
  for (unsigned i = 0; i < Features.size(); i++) {
    // Next record
    Record *R = Features[i];
    std::string Instance = R->getName();
    std::string Name = R->getValueAsString("Name");
    std::string Type = R->getValueAsString("Type");
    std::string Attribute = R->getValueAsString("Attribute");
    
    OS << "  " << Attribute << " = (Bits & " << Instance << ") != 0;\n";
  }
  OS << "}\n";
}

// 
// SubtargetEmitter::run - Main subtarget enumeration emitter.
//
void SubtargetEmitter::run(std::ostream &OS) {
  Target = CodeGenTarget().getName();

  EmitSourceFileHeader("Subtarget Enumeration Source Fragment", OS);

  OS << "#include \"llvm/Target/SubtargetFeature.h\"\n";
  OS << "#include \"llvm/Target/TargetInstrItineraries.h\"\n\n";
  
  Enumeration(OS, "FuncUnit", true);
  OS<<"\n";
//  Enumeration(OS, "InstrItinClass", false);
//  OS<<"\n";
  Enumeration(OS, "SubtargetFeature", true);
  OS<<"\n";
  FeatureKeyValues(OS);
  OS<<"\n";
  CPUKeyValues(OS);
  OS<<"\n";
  EmitData(OS);
  OS<<"\n";
  ParseFeaturesFunction(OS);
}