utils/TableGen/InstrSelectorEmitter.cpp

//===- InstrInfoEmitter.cpp - Generate a Instruction Set Desc. ------------===//
//
// This tablegen backend is responsible for emitting a description of the target
// instruction set for the code generator.
//
//===----------------------------------------------------------------------===//

#include "InstrSelectorEmitter.h"
#include "CodeGenWrappers.h"
#include "Record.h"
#include "Support/Debug.h"

NodeType::ArgResultTypes NodeType::Translate(Record *R) {
  const std::string &Name = R->getName();
  if (Name == "DNVT_void") return Void;
  if (Name == "DNVT_val" ) return Val;
  if (Name == "DNVT_arg0") return Arg0;
  if (Name == "DNVT_ptr" ) return Ptr;
  throw "Unknown DagNodeValType '" + Name + "'!";
}


//===----------------------------------------------------------------------===//
// TreePatternNode implementation
//

// updateNodeType - Set the node type of N to VT if VT contains information.  If
// N already contains a conflicting type, then throw an exception
//
bool TreePatternNode::updateNodeType(MVT::ValueType VT,
                                     const std::string &RecName) {
  if (VT == MVT::Other || getType() == VT) return false;
  if (getType() == MVT::Other) {
    setType(VT);
    return true;
  }

  throw "Type inferfence contradiction found for pattern " + RecName;
}

/// InstantiateNonterminals - If this pattern refers to any nonterminals which
/// are not themselves completely resolved, clone the nonterminal and resolve it
/// with the using context we provide.
///
void TreePatternNode::InstantiateNonterminals(InstrSelectorEmitter &ISE) {
  if (!isLeaf()) {
    for (unsigned i = 0, e = Children.size(); i != e; ++i)
      Children[i]->InstantiateNonterminals(ISE);
    return;
  }
  
  // If this is a leaf, it might be a reference to a nonterminal!  Check now.
  if (DefInit *DI = dynamic_cast<DefInit*>(getValue()))
    if (DI->getDef()->isSubClassOf("Nonterminal")) {
      Pattern *NT = ISE.getPattern(DI->getDef());
      if (!NT->isResolved()) {
        // We found an unresolved nonterminal reference.  Ask the ISE to clone
        // it for us, then update our reference to the fresh, new, resolved,
        // nonterminal.
        
        Value = new DefInit(ISE.InstantiateNonterminal(NT, getType()));
      }
    }
}


/// clone - Make a copy of this tree and all of its children.
///
TreePatternNode *TreePatternNode::clone() const {
  TreePatternNode *New;
  if (isLeaf()) {
    New = new TreePatternNode(Value);
  } else {
    std::vector<TreePatternNode*> CChildren(Children.size());
    for (unsigned i = 0, e = Children.size(); i != e; ++i)
      CChildren[i] = Children[i]->clone();
    New = new TreePatternNode(Operator, CChildren);
  }
  New->setType(Type);
  return New;
}


std::ostream &operator<<(std::ostream &OS, const TreePatternNode &N) {
  if (N.isLeaf())
    return OS << N.getType() << ":" << *N.getValue();
  OS << "(" << N.getType() << ":";
  OS << N.getOperator()->getName();
  
  const std::vector<TreePatternNode*> &Children = N.getChildren();
  if (!Children.empty()) {
    OS << " " << *Children[0];
    for (unsigned i = 1, e = Children.size(); i != e; ++i)
      OS << ", " << *Children[i];
  }  
  return OS << ")";
}

void TreePatternNode::dump() const { std::cerr << *this; }

//===----------------------------------------------------------------------===//
// Pattern implementation
//

// Parse the specified DagInit into a TreePattern which we can use.
//
Pattern::Pattern(PatternType pty, DagInit *RawPat, Record *TheRec,
                 InstrSelectorEmitter &ise)
  : PTy(pty), TheRecord(TheRec), ISE(ise) {

  // First, parse the pattern...
  Tree = ParseTreePattern(RawPat);

  // Run the type-inference engine...
  InferAllTypes();

  if (PTy == Instruction || PTy == Expander) {
    // Check to make sure there is not any unset types in the tree pattern...
    if (!isResolved()) {
      std::cerr << "In pattern: " << *Tree << "\n";
      error("Could not infer all types!");
    }

    // Check to see if we have a top-level (set) of a register.
    if (Tree->getOperator()->getName() == "set") {
      assert(Tree->getChildren().size() == 2 && "Set with != 2 arguments?");
      if (!Tree->getChild(0)->isLeaf())
        error("Arg #0 of set should be a register or register class!");
      DefInit *RegInit = dynamic_cast<DefInit*>(Tree->getChild(0)->getValue());
      if (RegInit == 0)
        error("LHS of 'set' expected to be a register or register class!");

      Result = RegInit->getDef();
      Tree = Tree->getChild(1);
    }
  }
}



void Pattern::error(const std::string &Msg) const {
  std::string M = "In ";
  switch (PTy) {
  case Nonterminal: M += "nonterminal "; break;
  case Instruction: M += "instruction "; break;
  case Expander   : M += "expander "; break;
  }
  throw M + TheRecord->getName() + ": " + Msg;  
}

/// getIntrinsicType - Check to see if the specified record has an intrinsic
/// type which should be applied to it.  This infer the type of register
/// references from the register file information, for example.
///
MVT::ValueType Pattern::getIntrinsicType(Record *R) const {
  // Check to see if this is a register or a register class...
  if (R->isSubClassOf("RegisterClass"))
    return getValueType(R->getValueAsDef("RegType"));
  else if (R->isSubClassOf("Nonterminal"))
    return ISE.ReadNonterminal(R)->getTree()->getType();
  else if (R->isSubClassOf("Register")) {
    std::cerr << "WARNING: Explicit registers not handled yet!\n";
    return MVT::Other;
  }

  throw "Error: Unknown value used: " + R->getName();
}

TreePatternNode *Pattern::ParseTreePattern(DagInit *DI) {
  Record *Operator = DI->getNodeType();
  const std::vector<Init*> &Args = DI->getArgs();

  if (Operator->isSubClassOf("ValueType")) {
    // If the operator is a ValueType, then this must be "type cast" of a leaf
    // node.
    if (Args.size() != 1)
      error("Type cast only valid for a leaf node!");
    
    Init *Arg = Args[0];
    TreePatternNode *New;
    if (DefInit *DI = dynamic_cast<DefInit*>(Arg)) {
      New = new TreePatternNode(DI);
      // If it's a regclass or something else known, set the type.
      New->setType(getIntrinsicType(DI->getDef()));
    } else {
      Arg->dump();
      error("Unknown leaf value for tree pattern!");
    }

    // Apply the type cast...
    New->updateNodeType(getValueType(Operator), TheRecord->getName());
    return New;
  }

  if (!ISE.getNodeTypes().count(Operator))
    error("Unrecognized node '" + Operator->getName() + "'!");

  std::vector<TreePatternNode*> Children;
  
  for (unsigned i = 0, e = Args.size(); i != e; ++i) {
    Init *Arg = Args[i];
    if (DagInit *DI = dynamic_cast<DagInit*>(Arg)) {
      Children.push_back(ParseTreePattern(DI));
    } else if (DefInit *DI = dynamic_cast<DefInit*>(Arg)) {
      Children.push_back(new TreePatternNode(DI));
      // If it's a regclass or something else known, set the type.
      Children.back()->setType(getIntrinsicType(DI->getDef()));
    } else {
      Arg->dump();
      error("Unknown leaf value for tree pattern!");
    }
  }

  return new TreePatternNode(Operator, Children);
}

void Pattern::InferAllTypes() {
  bool MadeChange, AnyUnset;
  do {
    MadeChange = false;
    AnyUnset = InferTypes(Tree, MadeChange);
  } while ((AnyUnset || MadeChange) && !(AnyUnset && !MadeChange));
  Resolved = !AnyUnset;
}


// InferTypes - Perform type inference on the tree, returning true if there
// are any remaining untyped nodes and setting MadeChange if any changes were
// made.
bool Pattern::InferTypes(TreePatternNode *N, bool &MadeChange) {
  if (N->isLeaf()) return N->getType() == MVT::Other;

  bool AnyUnset = false;
  Record *Operator = N->getOperator();
  assert(ISE.getNodeTypes().count(Operator) && "No node info for node!");
  const NodeType &NT = ISE.getNodeTypes()[Operator];

  // Check to see if we can infer anything about the argument types from the
  // return types...
  const std::vector<TreePatternNode*> &Children = N->getChildren();
  if (Children.size() != NT.ArgTypes.size())
    error("Incorrect number of children for " + Operator->getName() + " node!");

  for (unsigned i = 0, e = Children.size(); i != e; ++i) {
    TreePatternNode *Child = Children[i];
    AnyUnset |= InferTypes(Child, MadeChange);

    switch (NT.ArgTypes[i]) {
    case NodeType::Arg0:
      MadeChange |= Child->updateNodeType(Children[0]->getType(),
                                          TheRecord->getName());
      break;
    case NodeType::Val:
      if (Child->getType() == MVT::isVoid)
        error("Inferred a void node in an illegal place!");
      break;
    case NodeType::Ptr:
      MadeChange |= Child->updateNodeType(ISE.getTarget().getPointerType(),
                                          TheRecord->getName());
      break;
    default: assert(0 && "Invalid argument ArgType!");
    }
  }

  // See if we can infer anything about the return type now...
  switch (NT.ResultType) {
  case NodeType::Void:
    MadeChange |= N->updateNodeType(MVT::isVoid, TheRecord->getName());
    break;
  case NodeType::Arg0:
    MadeChange |= N->updateNodeType(Children[0]->getType(),
                                    TheRecord->getName());
    break;

  case NodeType::Ptr:
    MadeChange |= N->updateNodeType(ISE.getTarget().getPointerType(),
                                    TheRecord->getName());
    break;
  case NodeType::Val:
    if (N->getType() == MVT::isVoid)
      error("Inferred a void node in an illegal place!");
    break;
  default:
    assert(0 && "Unhandled type constraint!");
    break;
  }

  return AnyUnset | N->getType() == MVT::Other;
}

/// clone - This method is used to make an exact copy of the current pattern,
/// then change the "TheRecord" instance variable to the specified record.
///
Pattern *Pattern::clone(Record *R) const {
  assert(PTy == Nonterminal && "Can only clone nonterminals");
  return new Pattern(Tree->clone(), R, Resolved, ISE);
}



std::ostream &operator<<(std::ostream &OS, const Pattern &P) {
  switch (P.getPatternType()) {
  case Pattern::Nonterminal: OS << "Nonterminal pattern "; break;
  case Pattern::Instruction: OS << "Instruction pattern "; break;
  case Pattern::Expander:    OS << "Expander pattern    "; break;
  }

  OS << P.getRecord()->getName() << ":\t";

  if (Record *Result = P.getResult())
    OS << Result->getName() << " = ";
  OS << *P.getTree();

  if (!P.isResolved())
    OS << " [not completely resolved]";
  return OS;
}


//===----------------------------------------------------------------------===//
// PatternOrganizer implementation
//

/// addPattern - Add the specified pattern to the appropriate location in the
/// collection.
void PatternOrganizer::addPattern(Pattern *P) {
  std::string ValueName;
  if (P->getPatternType() == Pattern::Nonterminal) {
    // Just use the nonterminal name, which will already include the type if
    // it has been cloned.
    ValueName = P->getRecord()->getName();
  } else {
    if (P->getResult())
      ValueName += P->getResult()->getName()+"_";
    else
      ValueName += "Void_";
    ValueName += getName(P->getTree()->getType());
  }

  NodesForSlot &Nodes = AllPatterns[ValueName];
  if (!P->getTree()->isLeaf())
    Nodes[P->getTree()->getOperator()].push_back(P);
  else {
    // Right now we only support DefInit's with node types...
    DefInit *Val = dynamic_cast<DefInit*>(P->getTree()->getValue());
    if (!Val)
      throw std::string("We only support def inits in PatternOrganizer"
                        "::addPattern so far!");
    Nodes[Val->getDef()].push_back(P);
  }
}



//===----------------------------------------------------------------------===//
// InstrSelectorEmitter implementation
//

/// ReadNodeTypes - Read in all of the node types in the current RecordKeeper,
/// turning them into the more accessible NodeTypes data structure.
///
void InstrSelectorEmitter::ReadNodeTypes() {
  std::vector<Record*> Nodes = Records.getAllDerivedDefinitions("DagNode");
  DEBUG(std::cerr << "Getting node types: ");
  for (unsigned i = 0, e = Nodes.size(); i != e; ++i) {
    Record *Node = Nodes[i];
    
    // Translate the return type...
    NodeType::ArgResultTypes RetTy =
      NodeType::Translate(Node->getValueAsDef("RetType"));

    // Translate the arguments...
    ListInit *Args = Node->getValueAsListInit("ArgTypes");
    std::vector<NodeType::ArgResultTypes> ArgTypes;

    for (unsigned a = 0, e = Args->getSize(); a != e; ++a) {
      if (DefInit *DI = dynamic_cast<DefInit*>(Args->getElement(a)))
        ArgTypes.push_back(NodeType::Translate(DI->getDef()));
      else
        throw "In node " + Node->getName() + ", argument is not a Def!";

      if (a == 0 && ArgTypes.back() == NodeType::Arg0)
        throw "In node " + Node->getName() + ", arg 0 cannot have type 'arg0'!";
      if (ArgTypes.back() == NodeType::Void)
        throw "In node " + Node->getName() + ", args cannot be void type!";
    }
    if (RetTy == NodeType::Arg0 && Args->getSize() == 0)
      throw "In node " + Node->getName() +
            ", invalid return type for nullary node!";

    // Add the node type mapping now...
    NodeTypes[Node] = NodeType(RetTy, ArgTypes);
    DEBUG(std::cerr << Node->getName() << ", ");
  }
  DEBUG(std::cerr << "DONE!\n");
}

Pattern *InstrSelectorEmitter::ReadNonterminal(Record *R) {
  Pattern *&P = Patterns[R];
  if (P) return P;  // Don't reread it!

  DagInit *DI = R->getValueAsDag("Pattern");
  P = new Pattern(Pattern::Nonterminal, DI, R, *this);
  DEBUG(std::cerr << "Parsed " << *P << "\n");
  return P;
}


// ReadNonTerminals - Read in all nonterminals and incorporate them into our
// pattern database.
void InstrSelectorEmitter::ReadNonterminals() {
  std::vector<Record*> NTs = Records.getAllDerivedDefinitions("Nonterminal");
  for (unsigned i = 0, e = NTs.size(); i != e; ++i)
    ReadNonterminal(NTs[i]);
}


/// ReadInstructionPatterns - Read in all subclasses of Instruction, and process
/// those with a useful Pattern field.
///
void InstrSelectorEmitter::ReadInstructionPatterns() {
  std::vector<Record*> Insts = Records.getAllDerivedDefinitions("Instruction");
  for (unsigned i = 0, e = Insts.size(); i != e; ++i) {
    Record *Inst = Insts[i];
    if (DagInit *DI = dynamic_cast<DagInit*>(Inst->getValueInit("Pattern"))) {
      Patterns[Inst] = new Pattern(Pattern::Instruction, DI, Inst, *this);
      DEBUG(std::cerr << "Parsed " << *Patterns[Inst] << "\n");
    }
  }
}

/// ReadExpanderPatterns - Read in all expander patterns...
///
void InstrSelectorEmitter::ReadExpanderPatterns() {
  std::vector<Record*> Expanders = Records.getAllDerivedDefinitions("Expander");
  for (unsigned i = 0, e = Expanders.size(); i != e; ++i) {
    Record *Expander = Expanders[i];
    DagInit *DI = Expander->getValueAsDag("Pattern");
    Patterns[Expander] = new Pattern(Pattern::Expander, DI, Expander, *this);
    DEBUG(std::cerr << "Parsed " << *Patterns[Expander] << "\n");
  }
}


// InstantiateNonterminals - Instantiate any unresolved nonterminals with
// information from the context that they are used in.
//
void InstrSelectorEmitter::InstantiateNonterminals() {
  DEBUG(std::cerr << "Instantiating nonterminals:\n");
  for (std::map<Record*, Pattern*>::iterator I = Patterns.begin(),
         E = Patterns.end(); I != E; ++I)
    if (I->second->isResolved())
      I->second->InstantiateNonterminals();
}

/// InstantiateNonterminal - This method takes the nonterminal specified by
/// NT, which should not be completely resolved, clones it, applies ResultTy
/// to its root, then runs the type inference stuff on it.  This should
/// produce a newly resolved nonterminal, which we make a record for and
/// return.  To be extra fancy and efficient, this only makes one clone for
/// each type it is instantiated with.
Record *InstrSelectorEmitter::InstantiateNonterminal(Pattern *NT,
                                                     MVT::ValueType ResultTy) {
  assert(!NT->isResolved() && "Nonterminal is already resolved!");

  // Check to see if we have already instantiated this pair...
  Record* &Slot = InstantiatedNTs[std::make_pair(NT, ResultTy)];
  if (Slot) return Slot;
  
  Record *New = new Record(NT->getRecord()->getName()+"_"+getName(ResultTy));

  DEBUG(std::cerr << "  Nonterminal '" << NT->getRecord()->getName()
                  << "' for type '" << getName(ResultTy) << "', producing '"
                  << New->getName() << "'\n");

  // Copy the pattern...
  Pattern *NewPat = NT->clone(New);

  // Apply the type to the root...
  NewPat->getTree()->updateNodeType(ResultTy, New->getName());

  // Infer types...
  NewPat->InferAllTypes();

  // Make sure everything is good to go now...
  if (!NewPat->isResolved())
    NewPat->error("Instantiating nonterminal did not resolve all types!");

  // Add the pattern to the patterns map, add the record to the RecordKeeper,
  // return the new record.
  Patterns[New] = NewPat;
  Records.addDef(New);
  return Slot = New;
}

// 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())
      ComputableValues.addPattern(I->second);
}

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();

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

  CalculateComputableValues();
  
  // Output the slot number enums...
  OS << "\n\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 ReduceValue<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";

  // Start emitting the class...
  OS << "namespace {\n"
     << "  class " << Target.getName() << "ISel {\n"
     << "    SelectionDAG &DAG;\n"
     << "  public:\n"
     << "    X86ISel(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 << "_" << J->first->getName()
         << "(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(25+2*I->first.size(), ' ')
       << "MachineBasicBlock *MBB);\n";
  OS << "  };\n}\n\n";

  OS << "void X86ISel::generateCode() {\n"
     << "  SelectionDAGNode *Root = DAG.getRoot();\n"
     << "  assert(Root->getValueType() == ISD::Void && "
                                       "\"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";
}