C++ Pattern::getTree方法代码示例

// 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);
    }
}

/// 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));

  // Copy over the superclasses...
  const std::vector<Record*> &SCs = NT->getRecord()->getSuperClasses();
  for (unsigned i = 0, e = SCs.size(); i != e; ++i)
    New->addSuperClass(SCs[i]);

  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;
}

//.........这里部分代码省略.........
    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) {

//.........这里部分代码省略.........

    OS << Indent << "{ // ";

    if (Group.size() != 1) {
      OS << Group.size() << " size group...\n";
      OS << Indent << "  unsigned " << VarPrefix << "_Pattern = NoMatch;\n";
    } else {
      OS << *Group[0].first << "\n";
      OS << Indent << "  unsigned " << VarPrefix << "_Pattern = "
         << Group[0].first->getRecord()->getName() << "_Pattern;\n";
    }

    OS << Indent << "  unsigned " << LocCostName << " = ";
    if (Group.size() == 1)
      OS << "1;\n";    // Add inst cost if at individual rec
    else
      OS << "0;\n";

    // Loop over all of the operands, adding in their costs...
    TreePatternNode *N = Group[0].second;
    const std::vector<TreePatternNode*> &Children = N->getChildren();

    // If necessary, emit conditionals to check for the appropriate tree
    // structure here...
    for (unsigned i = 0, e = Children.size(); i != e; ++i) {
      TreePatternNode *C = Children[i];
      if (C->isLeaf()) {
        // We already calculated the cost for this leaf, add it in now...
        OS << Indent << "  " << LocCostName << " += "
           << VarPrefix << "_Op" << utostr(i) << "_"
           << C->getValueRecord()->getName() << "_Cost;\n";
      } else {
        // If it's not a leaf, we have to check to make sure that the current
        // node has the appropriate structure, then recurse into it...
        OS << Indent << "  if (" << VarPrefix << "_Op" << i
           << "->getNodeType() == ISD::" << getNodeName(C->getOperator())
           << ") {\n";
        std::vector<std::pair<Pattern*, TreePatternNode*> > SubPatterns;
        for (unsigned n = 0, e = Group.size(); n != e; ++n)
          SubPatterns.push_back(std::make_pair(Group[n].first,
                                               Group[n].second->getChild(i)));
        EmitMatchCosters(OS, SubPatterns, VarPrefix+"_Op"+utostr(i),
                         IndentAmt + 4);
        OS << Indent << "  }\n";
      }
    }

    // If the cost for this match is less than the minimum computed cost so far,
    // update the minimum cost and selected pattern.
    OS << Indent << "  if (" << LocCostName << " < " << LocCostName << "Min) { "
       << LocCostName << "Min = " << LocCostName << "; " << VarPrefix
       << "_PatternMin = " << VarPrefix << "_Pattern; }\n";
    
    OS << Indent << "}\n";
  }
#endif

  for (unsigned i = 0, e = Patterns.size(); i != e; ++i) {
    Pattern *P = Patterns[i].first;
    TreePatternNode *PTree = P->getTree();
    unsigned PatternCost = 1;

    // Check to see if there are any non-leaf elements in the pattern.  If so,
    // we need to emit a predicate for this match.
    bool AnyNonLeaf = false;
    for (unsigned c = 0, e = PTree->getNumChildren(); c != e; ++c)
      if (!PTree->getChild(c)->isLeaf()) {
        AnyNonLeaf = true;
        break;
      }

    if (!AnyNonLeaf) {   // No predicate necessary, just output a scope...
      OS << "  {// " << *P << "\n";
    } else {
      // We need to emit a predicate to make sure the tree pattern matches, do
      // so now...
      OS << "  if (1";
      for (unsigned c = 0, e = PTree->getNumChildren(); c != e; ++c)
        if (!PTree->getChild(c)->isLeaf())
          EmitPatternPredicates(PTree->getChild(c),
                                VarPrefix + "_Op" + utostr(c), OS);

      OS << ") {\n    // " << *P << "\n";
    }

    OS << "    unsigned PatCost = " << PatternCost;

    for (unsigned c = 0, e = PTree->getNumChildren(); c != e; ++c)
      if (PTree->getChild(c)->isLeaf()) {
        OS << " + " << VarPrefix << "_Op" << c << "_"
           << PTree->getChild(c)->getValueRecord()->getName() << "_Cost";
      } else {
        EmitPatternCosts(PTree->getChild(c), VarPrefix + "_Op" + utostr(c), OS);
      }
    OS << ";\n";
    OS << "    if (PatCost < MinCost) { MinCost = PatCost; Pattern = "
       << P->getRecord()->getName() << "_Pattern; }\n"
       << "  }\n";
  }
}