// CalculateComputableValues - Fill in the ComputableValues map through
// analysis of the patterns we are playing with.
void InstrSelectorEmitter::CalculateComputableValues() {
  // Loop over all of the patterns, adding them to the ComputableValues map
  for (std::map<Record*, Pattern*>::iterator I = Patterns.begin(),
         E = Patterns.end(); I != E; ++I)
    if (I->second->isResolved()) {
      // We don't want to add patterns like R32 = R32.  This is a hack working
      // around a special case of a general problem, but for now we explicitly
      // forbid these patterns.  They can never match anyway.
      Pattern *P = I->second;
      if (!P->getResult() || !P->getTree()->isLeaf() ||
          P->getResult() != P->getTree()->getValueRecord())
        ComputableValues.addPattern(P);
    }
}
void InstrSelectorEmitter::run(std::ostream &OS) {
  // Type-check all of the node types to ensure we "understand" them.
  ReadNodeTypes();
  
  // Read in all of the nonterminals, instructions, and expanders...
  ReadNonterminals();
  ReadInstructionPatterns();
  ReadExpanderPatterns();

  // Instantiate any unresolved nonterminals with information from the context
  // that they are used in.
  InstantiateNonterminals();

  // Clear InstantiatedNTs, we don't need it anymore...
  InstantiatedNTs.clear();

  DEBUG(std::cerr << "Patterns acquired:\n");
  for (std::map<Record*, Pattern*>::iterator I = Patterns.begin(),
         E = Patterns.end(); I != E; ++I)
    if (I->second->isResolved())
      DEBUG(std::cerr << "  " << *I->second << "\n");

  CalculateComputableValues();
  
  OS << "#include \"llvm/CodeGen/MachineInstrBuilder.h\"\n";

  EmitSourceFileHeader("Instruction Selector for the " + Target.getName() +
                       " target", OS);

  // Output the slot number enums...
  OS << "\nenum { // Slot numbers...\n"
     << "  LastBuiltinSlot = ISD::NumBuiltinSlots-1, // Start numbering here\n";
  for (PatternOrganizer::iterator I = ComputableValues.begin(),
         E = ComputableValues.end(); I != E; ++I)
    OS << "  " << I->first << "_Slot,\n";
  OS << "  NumSlots\n};\n\n// Reduction value typedefs...\n";

  // Output the reduction value typedefs...
  for (PatternOrganizer::iterator I = ComputableValues.begin(),
         E = ComputableValues.end(); I != E; ++I) {

    OS << "typedef ReducedValue<unsigned, " << I->first
       << "_Slot> ReducedValue_" << I->first << ";\n";
  }

  // Output the pattern enums...
  OS << "\n\n"
     << "enum { // Patterns...\n"
     << "  NotComputed = 0,\n"
     << "  NoMatchPattern, \n";
  for (PatternOrganizer::iterator I = ComputableValues.begin(),
         E = ComputableValues.end(); I != E; ++I) {
    OS << "  // " << I->first << " patterns...\n";
    for (PatternOrganizer::NodesForSlot::iterator J = I->second.begin(),
           E = I->second.end(); J != E; ++J)
      for (unsigned i = 0, e = J->second.size(); i != e; ++i)
        OS << "  " << J->second[i]->getRecord()->getName() << "_Pattern,\n";
  }
  OS << "};\n\n";

  //===--------------------------------------------------------------------===//
  // Emit the class definition...
  //
  OS << "namespace {\n"
     << "  class " << Target.getName() << "ISel {\n"
     << "    SelectionDAG &DAG;\n"
     << "  public:\n"
     << "    " << Target.getName () << "ISel(SelectionDAG &D) : DAG(D) {}\n"
     << "    void generateCode();\n"
     << "  private:\n"
     << "    unsigned makeAnotherReg(const TargetRegisterClass *RC) {\n"
     << "      return DAG.getMachineFunction().getSSARegMap()->createVirt"
                                       "ualRegister(RC);\n"
     << "    }\n\n"
     << "    // DAG matching methods for classes... all of these methods"
                                       " return the cost\n"
     << "    // of producing a value of the specified class and type, which"
                                       " also gets\n"
     << "    // added to the DAG node.\n";

  // Output all of the matching prototypes for slots...
  for (PatternOrganizer::iterator I = ComputableValues.begin(),
         E = ComputableValues.end(); I != E; ++I)
    OS << "    unsigned Match_" << I->first << "(SelectionDAGNode *N);\n";
  OS << "\n    // DAG matching methods for DAG nodes...\n";

  // Output all of the matching prototypes for slot/node pairs
  for (PatternOrganizer::iterator I = ComputableValues.begin(),
         E = ComputableValues.end(); I != E; ++I)
    for (PatternOrganizer::NodesForSlot::iterator J = I->second.begin(),
           E = I->second.end(); J != E; ++J)
      OS << "    unsigned Match_" << I->first << "_" << getNodeName(J->first)
         << "(SelectionDAGNode *N);\n";

  // Output all of the dag reduction methods prototypes...
  OS << "\n    // DAG reduction methods...\n";
  for (PatternOrganizer::iterator I = ComputableValues.begin(),
         E = ComputableValues.end(); I != E; ++I)
    OS << "    ReducedValue_" << I->first << " *Reduce_" << I->first
       << "(SelectionDAGNode *N,\n" << std::string(27+2*I->first.size(), ' ')
       << "MachineBasicBlock *MBB);\n";
  OS << "  };\n}\n\n";

  // Emit the generateCode entry-point...
  OS << "void " << Target.getName () << "ISel::generateCode() {\n"
     << "  SelectionDAGNode *Root = DAG.getRoot();\n"
     << "  assert(Root->getValueType() == MVT::isVoid && "
                                       "\"Root of DAG produces value??\");\n\n"
     << "  std::cerr << \"\\n\";\n"
     << "  unsigned Cost = Match_Void_void(Root);\n"
     << "  if (Cost >= ~0U >> 1) {\n"
     << "    std::cerr << \"Match failed!\\n\";\n"
     << "    Root->dump();\n"
     << "    abort();\n"
     << "  }\n\n"
     << "  std::cerr << \"Total DAG Cost: \" << Cost << \"\\n\\n\";\n\n"
     << "  Reduce_Void_void(Root, 0);\n"
     << "}\n\n"
     << "//===" << std::string(70, '-') << "===//\n"
     << "//  Matching methods...\n"
     << "//\n\n";

  //===--------------------------------------------------------------------===//
  // Emit all of the matcher methods...
  //
  for (PatternOrganizer::iterator I = ComputableValues.begin(),
         E = ComputableValues.end(); I != E; ++I) {
    const std::string &SlotName = I->first;
    OS << "unsigned " << Target.getName() << "ISel::Match_" << SlotName
       << "(SelectionDAGNode *N) {\n"
       << "  assert(N->getValueType() == MVT::"
       << getEnumName((*I->second.begin()).second[0]->getTree()->getType())
       << ");\n" << "  // If we already have a cost available for " << SlotName
       << " use it!\n"
       << "  if (N->getPatternFor(" << SlotName << "_Slot))\n"
       << "    return N->getCostFor(" << SlotName << "_Slot);\n\n"
       << "  unsigned Cost;\n"
       << "  switch (N->getNodeType()) {\n"
       << "  default: Cost = ~0U >> 1;   // Match failed\n"
       << "           N->setPatternCostFor(" << SlotName << "_Slot, NoMatchPattern, Cost, NumSlots);\n"
       << "           break;\n";

    for (PatternOrganizer::NodesForSlot::iterator J = I->second.begin(),
           E = I->second.end(); J != E; ++J)
      if (!J->first->isSubClassOf("Nonterminal"))
        OS << "  case ISD::" << getNodeName(J->first) << ":\tCost = Match_"
           << SlotName << "_" << getNodeName(J->first) << "(N); break;\n";
    OS << "  }\n";  // End of the switch statement

    // Emit any patterns which have a nonterminal leaf as the RHS.  These may
    // match multiple root nodes, so they cannot be handled with the switch...
    for (PatternOrganizer::NodesForSlot::iterator J = I->second.begin(),
           E = I->second.end(); J != E; ++J)
      if (J->first->isSubClassOf("Nonterminal")) {
        OS << "  unsigned " << J->first->getName() << "_Cost = Match_"
           << getNodeName(J->first) << "(N);\n"
           << "  if (" << getNodeName(J->first) << "_Cost < Cost) Cost = "
           << getNodeName(J->first) << "_Cost;\n";
      }

    OS << "  return Cost;\n}\n\n";

    for (PatternOrganizer::NodesForSlot::iterator J = I->second.begin(),
           E = I->second.end(); J != E; ++J) {
      Record *Operator = J->first;
      bool isNonterm = Operator->isSubClassOf("Nonterminal");
      if (!isNonterm) {
        OS << "unsigned " << Target.getName() << "ISel::Match_";
        if (!isNonterm) OS << SlotName << "_";
        OS << getNodeName(Operator) << "(SelectionDAGNode *N) {\n"
           << "  unsigned Pattern = NoMatchPattern;\n"
           << "  unsigned MinCost = ~0U >> 1;\n";
        
        std::vector<std::pair<Pattern*, TreePatternNode*> > Patterns;
        for (unsigned i = 0, e = J->second.size(); i != e; ++i)
          Patterns.push_back(std::make_pair(J->second[i],
                                            J->second[i]->getTree()));
        EmitMatchCosters(OS, Patterns, "N", 2);
        
        OS << "\n  N->setPatternCostFor(" << SlotName
           << "_Slot, Pattern, MinCost, NumSlots);\n"
           << "  return MinCost;\n"
           << "}\n";
      }
    }
  }

  //===--------------------------------------------------------------------===//
  // Emit all of the reducer methods...
  //
  OS << "\n\n//===" << std::string(70, '-') << "===//\n"
     << "// Reducer methods...\n"
     << "//\n";

  for (PatternOrganizer::iterator I = ComputableValues.begin(),
         E = ComputableValues.end(); I != E; ++I) {
    const std::string &SlotName = I->first;
    OS << "ReducedValue_" << SlotName << " *" << Target.getName()
       << "ISel::Reduce_" << SlotName
       << "(SelectionDAGNode *N, MachineBasicBlock *MBB) {\n"
       << "  ReducedValue_" << SlotName << " *Val = N->hasValue<ReducedValue_"
       << SlotName << ">(" << SlotName << "_Slot);\n"
       << "  if (Val) return Val;\n"
       << "  if (N->getBB()) MBB = N->getBB();\n\n"
       << "  switch (N->getPatternFor(" << SlotName << "_Slot)) {\n";

    // Loop over all of the patterns that can produce a value for this slot...
    PatternOrganizer::NodesForSlot &NodesForSlot = I->second;
    for (PatternOrganizer::NodesForSlot::iterator J = NodesForSlot.begin(),
           E = NodesForSlot.end(); J != E; ++J)
      for (unsigned i = 0, e = J->second.size(); i != e; ++i) {
        Pattern *P = J->second[i];
        OS << "  case " << P->getRecord()->getName() << "_Pattern: {\n"
           << "    // " << *P << "\n";
        // Loop over the operands, reducing them...
        std::vector<std::pair<TreePatternNode*, std::string> > Operands;
        ReduceAllOperands(P->getTree(), "N", Operands, OS);
        
        // Now that we have reduced all of our operands, and have the values
        // that reduction produces, perform the reduction action for this
        // pattern.
        std::string Result;

        // If the pattern produces a register result, generate a new register
        // now.
        if (Record *R = P->getResult()) {
          assert(R->isSubClassOf("RegisterClass") &&
                 "Only handle register class results so far!");
          OS << "    unsigned NewReg = makeAnotherReg(" << Target.getName()
             << "::" << R->getName() << "RegisterClass);\n";
          Result = "NewReg";
          DEBUG(OS << "    std::cerr << \"%reg\" << NewReg << \" =\t\";\n");
        } else {
          DEBUG(OS << "    std::cerr << \"\t\t\";\n");
          Result = "0";
        }

        // Print out the pattern that matched...
        DEBUG(OS << "    std::cerr << \"  " << P->getRecord()->getName() <<'"');
        DEBUG(for (unsigned i = 0, e = Operands.size(); i != e; ++i)
                if (Operands[i].first->isLeaf()) {
                  Record *RV = Operands[i].first->getValueRecord();
                  assert(RV->isSubClassOf("RegisterClass") &&
                         "Only handles registers here so far!");
                  OS << " << \" %reg\" << " << Operands[i].second
                     << "->Val";
                } else {
                  OS << " << ' ' << " << Operands[i].second
                     << "->Val";
                });
        DEBUG(OS << " << \"\\n\";\n");
        
        // Generate the reduction code appropriate to the particular type of
        // pattern that this is...
        switch (P->getPatternType()) {
        case Pattern::Instruction:
          // Instruction patterns just emit a single MachineInstr, using BuildMI
          OS << "    BuildMI(MBB, " << Target.getName() << "::"
             << P->getRecord()->getName() << ", " << Operands.size();
          if (P->getResult()) OS << ", NewReg";
          OS << ")";

          for (unsigned i = 0, e = Operands.size(); i != e; ++i) {
            TreePatternNode *Op = Operands[i].first;
            if (Op->isLeaf()) {
              Record *RV = Op->getValueRecord();
              assert(RV->isSubClassOf("RegisterClass") &&
                     "Only handles registers here so far!");
              OS << ".addReg(" << Operands[i].second << "->Val)";
            } else if (Op->getOperator()->getName() == "imm") {
              OS << ".addZImm(" << Operands[i].second << "->Val)";
            } else if (Op->getOperator()->getName() == "basicblock") {
              OS << ".addMBB(" << Operands[i].second << "->Val)";
            } else {
              assert(0 && "Unknown value type!");
            }
          }
          OS << ";\n";
          break;
        case Pattern::Expander: {
          // Expander patterns emit one machine instr for each instruction in
          // the list of instructions expanded to.
          ListInit *Insts = P->getRecord()->getValueAsListInit("Result");
          for (unsigned IN = 0, e = Insts->getSize(); IN != e; ++IN) {
            DagInit *DIInst = dynamic_cast<DagInit*>(Insts->getElement(IN));
            if (!DIInst) P->error("Result list must contain instructions!");
            Record *InstRec  = DIInst->getNodeType();
            Pattern *InstPat = getPattern(InstRec);
            if (!InstPat || InstPat->getPatternType() != Pattern::Instruction)
              P->error("Instruction list must contain Instruction patterns!");
            
            bool hasResult = InstPat->getResult() != 0;
            if (InstPat->getNumArgs() != DIInst->getNumArgs()-hasResult) {
              P->error("Incorrect number of arguments specified for inst '" +
                       InstPat->getRecord()->getName() + "' in result list!");
            }

            // Start emission of the instruction...
            OS << "    BuildMI(MBB, " << Target.getName() << "::"
               << InstRec->getName() << ", "
               << DIInst->getNumArgs()-hasResult;
            // Emit register result if necessary..
            if (hasResult) {
              std::string ArgNameVal =
                getArgName(P, DIInst->getArgName(0), Operands);
              PrintExpanderOperand(DIInst->getArg(0), ArgNameVal,
                                   InstPat->getResultNode(), P, false,
                                   OS << ", ");
            }
            OS << ")";

            for (unsigned i = hasResult, e = DIInst->getNumArgs(); i != e; ++i){
              std::string ArgNameVal =
                getArgName(P, DIInst->getArgName(i), Operands);

              PrintExpanderOperand(DIInst->getArg(i), ArgNameVal,
                                   InstPat->getArg(i-hasResult), P, true, OS);
            }

            OS << ";\n";
          }
          break;
        }
        default:
          assert(0 && "Reduction of this type of pattern not implemented!");
        }

        OS << "    Val = new ReducedValue_" << SlotName << "(" << Result<<");\n"
           << "    break;\n"
           << "  }\n";
      }
    
    
    OS << "  default: assert(0 && \"Unknown " << SlotName << " pattern!\");\n"
       << "  }\n\n  N->addValue(Val);  // Do not ever recalculate this\n"
       << "  return Val;\n}\n\n";
  }