C++ selectiondag::allnodes_iterator类代码示例

void VDAGToDAGISel::PostprocessISelDAG() {
  CurDAG->AssignTopologicalOrder();
  HandleSDNode Dummy(CurDAG->getRoot());

  for (SelectionDAG::allnodes_iterator NI = CurDAG->allnodes_begin();
       NI != CurDAG->allnodes_end(); ++NI) {
    if (NI->getOpcode() == ISD::CopyToReg)
      CopyToReg(*CurDAG, NI);
  }
  CurDAG->setRoot(Dummy.getValue());
}

// After instruction selection, insert COPY_TO_REGCLASS nodes to help in
// choosing the proper register classes.
void BlackfinDAGToDAGISel::FixRegisterClasses(SelectionDAG &DAG) {
  const BlackfinInstrInfo &TII = getInstrInfo();
  const BlackfinRegisterInfo *TRI = getRegisterInfo();
  DAG.AssignTopologicalOrder();
  HandleSDNode Dummy(DAG.getRoot());

  for (SelectionDAG::allnodes_iterator NI = DAG.allnodes_begin();
       NI != DAG.allnodes_end(); ++NI) {
    if (NI->use_empty() || !NI->isMachineOpcode())
      continue;
    const TargetInstrDesc &DefTID = TII.get(NI->getMachineOpcode());
    for (SDNode::use_iterator UI = NI->use_begin(); !UI.atEnd(); ++UI) {
      if (!UI->isMachineOpcode())
        continue;

      if (UI.getUse().getResNo() >= DefTID.getNumDefs())
        continue;
      const TargetRegisterClass *DefRC =
        DefTID.OpInfo[UI.getUse().getResNo()].getRegClass(TRI);

      const TargetInstrDesc &UseTID = TII.get(UI->getMachineOpcode());
      if (UseTID.getNumDefs()+UI.getOperandNo() >= UseTID.getNumOperands())
        continue;
      const TargetRegisterClass *UseRC =
        UseTID.OpInfo[UseTID.getNumDefs()+UI.getOperandNo()].getRegClass(TRI);
      if (!DefRC || !UseRC)
        continue;
      // We cannot copy CC <-> !(CC/D)
      if ((isCC(DefRC) && !isDCC(UseRC)) || (isCC(UseRC) && !isDCC(DefRC))) {
        SDNode *Copy =
          DAG.getMachineNode(TargetOpcode::COPY_TO_REGCLASS,
                             NI->getDebugLoc(),
                             MVT::i32,
                             UI.getUse().get(),
                             DAG.getTargetConstant(BF::DRegClassID, MVT::i32));
        UpdateNodeOperand(DAG, *UI, UI.getOperandNo(), SDValue(Copy, 0));
      }
    }
  }
  DAG.setRoot(Dummy.getValue());
}

/// PerformExpensiveChecks - Do extensive, expensive, sanity checking.
void DAGTypeLegalizer::PerformExpensiveChecks() {
  // If a node is not processed, then none of its values should be mapped by any
  // of PromotedIntegers, ExpandedIntegers, ..., ReplacedValues.

  // If a node is processed, then each value with an illegal type must be mapped
  // by exactly one of PromotedIntegers, ExpandedIntegers, ..., ReplacedValues.
  // Values with a legal type may be mapped by ReplacedValues, but not by any of
  // the other maps.

  // Note that these invariants may not hold momentarily when processing a node:
  // the node being processed may be put in a map before being marked Processed.

  // Note that it is possible to have nodes marked NewNode in the DAG.  This can
  // occur in two ways.  Firstly, a node may be created during legalization but
  // never passed to the legalization core.  This is usually due to the implicit
  // folding that occurs when using the DAG.getNode operators.  Secondly, a new
  // node may be passed to the legalization core, but when analyzed may morph
  // into a different node, leaving the original node as a NewNode in the DAG.
  // A node may morph if one of its operands changes during analysis.  Whether
  // it actually morphs or not depends on whether, after updating its operands,
  // it is equivalent to an existing node: if so, it morphs into that existing
  // node (CSE).  An operand can change during analysis if the operand is a new
  // node that morphs, or it is a processed value that was mapped to some other
  // value (as recorded in ReplacedValues) in which case the operand is turned
  // into that other value.  If a node morphs then the node it morphed into will
  // be used instead of it for legalization, however the original node continues
  // to live on in the DAG.
  // The conclusion is that though there may be nodes marked NewNode in the DAG,
  // all uses of such nodes are also marked NewNode: the result is a fungus of
  // NewNodes growing on top of the useful nodes, and perhaps using them, but
  // not used by them.

  // If a value is mapped by ReplacedValues, then it must have no uses, except
  // by nodes marked NewNode (see above).

  // The final node obtained by mapping by ReplacedValues is not marked NewNode.
  // Note that ReplacedValues should be applied iteratively.

  // Note that the ReplacedValues map may also map deleted nodes (by iterating
  // over the DAG we never dereference deleted nodes).  This means that it may
  // also map nodes marked NewNode if the deallocated memory was reallocated as
  // another node, and that new node was not seen by the LegalizeTypes machinery
  // (for example because it was created but not used).  In general, we cannot
  // distinguish between new nodes and deleted nodes.
  SmallVector<SDNode*, 16> NewNodes;
  for (SelectionDAG::allnodes_iterator I = DAG.allnodes_begin(),
       E = DAG.allnodes_end(); I != E; ++I) {
    // Remember nodes marked NewNode - they are subject to extra checking below.
    if (I->getNodeId() == NewNode)
      NewNodes.push_back(I);

    for (unsigned i = 0, e = I->getNumValues(); i != e; ++i) {
      SDValue Res(I, i);
      bool Failed = false;

      unsigned Mapped = 0;
      if (ReplacedValues.find(Res) != ReplacedValues.end()) {
        Mapped |= 1;
        // Check that remapped values are only used by nodes marked NewNode.
        for (SDNode::use_iterator UI = I->use_begin(), UE = I->use_end();
             UI != UE; ++UI)
          if (UI.getUse().getResNo() == i)
            assert(UI->getNodeId() == NewNode &&
                   "Remapped value has non-trivial use!");

        // Check that the final result of applying ReplacedValues is not
        // marked NewNode.
        SDValue NewVal = ReplacedValues[Res];
        DenseMap<SDValue, SDValue>::iterator I = ReplacedValues.find(NewVal);
        while (I != ReplacedValues.end()) {
          NewVal = I->second;
          I = ReplacedValues.find(NewVal);
        }
        assert(NewVal.getNode()->getNodeId() != NewNode &&
               "ReplacedValues maps to a new node!");
      }
      if (PromotedIntegers.find(Res) != PromotedIntegers.end())
        Mapped |= 2;
      if (SoftenedFloats.find(Res) != SoftenedFloats.end())
        Mapped |= 4;
      if (ScalarizedVectors.find(Res) != ScalarizedVectors.end())
        Mapped |= 8;
      if (ExpandedIntegers.find(Res) != ExpandedIntegers.end())
        Mapped |= 16;
      if (ExpandedFloats.find(Res) != ExpandedFloats.end())
        Mapped |= 32;
      if (SplitVectors.find(Res) != SplitVectors.end())
        Mapped |= 64;
      if (WidenedVectors.find(Res) != WidenedVectors.end())
        Mapped |= 128;

      if (I->getNodeId() != Processed) {
        // Since we allow ReplacedValues to map deleted nodes, it may map nodes
        // marked NewNode too, since a deleted node may have been reallocated as
        // another node that has not been seen by the LegalizeTypes machinery.
        if ((I->getNodeId() == NewNode && Mapped > 1) ||
            (I->getNodeId() != NewNode && Mapped != 0)) {
          dbgs() << "Unprocessed value in a map!";
          Failed = true;
//.........这里部分代码省略.........

/// run - This is the main entry point for the type legalizer.  This does a
/// top-down traversal of the dag, legalizing types as it goes.  Returns "true"
/// if it made any changes.
bool DAGTypeLegalizer::run() {
  bool Changed = false;

  // Create a dummy node (which is not added to allnodes), that adds a reference
  // to the root node, preventing it from being deleted, and tracking any
  // changes of the root.
  HandleSDNode Dummy(DAG.getRoot());
  Dummy.setNodeId(Unanalyzed);

  // The root of the dag may dangle to deleted nodes until the type legalizer is
  // done.  Set it to null to avoid confusion.
  DAG.setRoot(SDValue());

  // Walk all nodes in the graph, assigning them a NodeId of 'ReadyToProcess'
  // (and remembering them) if they are leaves and assigning 'Unanalyzed' if
  // non-leaves.
  for (SelectionDAG::allnodes_iterator I = DAG.allnodes_begin(),
       E = DAG.allnodes_end(); I != E; ++I) {
    if (I->getNumOperands() == 0) {
      I->setNodeId(ReadyToProcess);
      Worklist.push_back(I);
    } else {
      I->setNodeId(Unanalyzed);
    }
  }

  // Now that we have a set of nodes to process, handle them all.
  while (!Worklist.empty()) {
#ifndef XDEBUG
    if (EnableExpensiveChecks)
#endif
      PerformExpensiveChecks();

    SDNode *N = Worklist.back();
    Worklist.pop_back();
    assert(N->getNodeId() == ReadyToProcess &&
           "Node should be ready if on worklist!");

    if (IgnoreNodeResults(N))
      goto ScanOperands;

    // Scan the values produced by the node, checking to see if any result
    // types are illegal.
    for (unsigned i = 0, NumResults = N->getNumValues(); i < NumResults; ++i) {
      EVT ResultVT = N->getValueType(i);
      switch (getTypeAction(ResultVT)) {
      case TargetLowering::TypeLegal:
        break;
      // The following calls must take care of *all* of the node's results,
      // not just the illegal result they were passed (this includes results
      // with a legal type).  Results can be remapped using ReplaceValueWith,
      // or their promoted/expanded/etc values registered in PromotedIntegers,
      // ExpandedIntegers etc.
      case TargetLowering::TypePromoteInteger:
        PromoteIntegerResult(N, i);
        Changed = true;
        goto NodeDone;
      case TargetLowering::TypeExpandInteger:
        ExpandIntegerResult(N, i);
        Changed = true;
        goto NodeDone;
      case TargetLowering::TypeSoftenFloat:
        SoftenFloatResult(N, i);
        Changed = true;
        goto NodeDone;
      case TargetLowering::TypeExpandFloat:
        ExpandFloatResult(N, i);
        Changed = true;
        goto NodeDone;
      case TargetLowering::TypeScalarizeVector:
        ScalarizeVectorResult(N, i);
        Changed = true;
        goto NodeDone;
      case TargetLowering::TypeSplitVector:
        SplitVectorResult(N, i);
        Changed = true;
        goto NodeDone;
      case TargetLowering::TypeWidenVector:
        WidenVectorResult(N, i);
        Changed = true;
        goto NodeDone;
      case TargetLowering::TypePromoteFloat:
        PromoteFloatResult(N, i);
        Changed = true;
        goto NodeDone;
      }
    }

ScanOperands:
    // Scan the operand list for the node, handling any nodes with operands that
    // are illegal.
    {
    unsigned NumOperands = N->getNumOperands();
    bool NeedsReanalyzing = false;
    unsigned i;
    for (i = 0; i != NumOperands; ++i) {
      if (IgnoreNodeResults(N->getOperand(i).getNode()))
//.........这里部分代码省略.........

void ScheduleDAGSDNodes::BuildSchedUnits() {
  // During scheduling, the NodeId field of SDNode is used to map SDNodes
  // to their associated SUnits by holding SUnits table indices. A value
  // of -1 means the SDNode does not yet have an associated SUnit.
  unsigned NumNodes = 0;
  for (SelectionDAG::allnodes_iterator NI = DAG->allnodes_begin(),
       E = DAG->allnodes_end(); NI != E; ++NI) {
    NI->setNodeId(-1);
    ++NumNodes;
  }

  // Reserve entries in the vector for each of the SUnits we are creating.  This
  // ensure that reallocation of the vector won't happen, so SUnit*'s won't get
  // invalidated.
  // FIXME: Multiply by 2 because we may clone nodes during scheduling.
  // This is a temporary workaround.
  SUnits.reserve(NumNodes * 2);

  // Add all nodes in depth first order.
  SmallVector<SDNode*, 64> Worklist;
  SmallPtrSet<SDNode*, 64> Visited;
  Worklist.push_back(DAG->getRoot().getNode());
  Visited.insert(DAG->getRoot().getNode());

  SmallVector<SUnit*, 8> CallSUnits;
  while (!Worklist.empty()) {
    SDNode *NI = Worklist.pop_back_val();

    // Add all operands to the worklist unless they've already been added.
    for (unsigned i = 0, e = NI->getNumOperands(); i != e; ++i)
      if (Visited.insert(NI->getOperand(i).getNode()))
        Worklist.push_back(NI->getOperand(i).getNode());

    if (isPassiveNode(NI))  // Leaf node, e.g. a TargetImmediate.
      continue;

    // If this node has already been processed, stop now.
    if (NI->getNodeId() != -1) continue;

    SUnit *NodeSUnit = newSUnit(NI);

    // See if anything is glued to this node, if so, add them to glued
    // nodes.  Nodes can have at most one glue input and one glue output.  Glue
    // is required to be the last operand and result of a node.

    // Scan up to find glued preds.
    SDNode *N = NI;
    while (N->getNumOperands() &&
           N->getOperand(N->getNumOperands()-1).getValueType() == MVT::Glue) {
      N = N->getOperand(N->getNumOperands()-1).getNode();
      assert(N->getNodeId() == -1 && "Node already inserted!");
      N->setNodeId(NodeSUnit->NodeNum);
      if (N->isMachineOpcode() && TII->get(N->getMachineOpcode()).isCall())
        NodeSUnit->isCall = true;
    }

    // Scan down to find any glued succs.
    N = NI;
    while (N->getValueType(N->getNumValues()-1) == MVT::Glue) {
      SDValue GlueVal(N, N->getNumValues()-1);

      // There are either zero or one users of the Glue result.
      bool HasGlueUse = false;
      for (SDNode::use_iterator UI = N->use_begin(), E = N->use_end();
           UI != E; ++UI)
        if (GlueVal.isOperandOf(*UI)) {
          HasGlueUse = true;
          assert(N->getNodeId() == -1 && "Node already inserted!");
          N->setNodeId(NodeSUnit->NodeNum);
          N = *UI;
          if (N->isMachineOpcode() && TII->get(N->getMachineOpcode()).isCall())
            NodeSUnit->isCall = true;
          break;
        }
      if (!HasGlueUse) break;
    }

    if (NodeSUnit->isCall)
      CallSUnits.push_back(NodeSUnit);

    // Schedule zero-latency TokenFactor below any nodes that may increase the
    // schedule height. Otherwise, ancestors of the TokenFactor may appear to
    // have false stalls.
    if (NI->getOpcode() == ISD::TokenFactor)
      NodeSUnit->isScheduleLow = true;

    // If there are glue operands involved, N is now the bottom-most node
    // of the sequence of nodes that are glued together.
    // Update the SUnit.
    NodeSUnit->setNode(N);
    assert(N->getNodeId() == -1 && "Node already inserted!");
    N->setNodeId(NodeSUnit->NodeNum);

    // Compute NumRegDefsLeft. This must be done before AddSchedEdges.
    InitNumRegDefsLeft(NodeSUnit);

    // Assign the Latency field of NodeSUnit using target-provided information.
    computeLatency(NodeSUnit);
  }

//.........这里部分代码省略.........

void ScheduleDAGSDNodes::BuildSchedUnits() {
  // During scheduling, the NodeId field of SDNode is used to map SDNodes
  // to their associated SUnits by holding SUnits table indices. A value
  // of -1 means the SDNode does not yet have an associated SUnit.
  unsigned NumNodes = 0;
  for (SelectionDAG::allnodes_iterator NI = DAG->allnodes_begin(),
       E = DAG->allnodes_end(); NI != E; ++NI) {
    NI->setNodeId(-1);
    ++NumNodes;
  }

  // Reserve entries in the vector for each of the SUnits we are creating.  This
  // ensure that reallocation of the vector won't happen, so SUnit*'s won't get
  // invalidated.
  // FIXME: Multiply by 2 because we may clone nodes during scheduling.
  // This is a temporary workaround.
  SUnits.reserve(NumNodes * 2);
  
  // Check to see if the scheduler cares about latencies.
  bool UnitLatencies = ForceUnitLatencies();

  // Add all nodes in depth first order.
  SmallVector<SDNode*, 64> Worklist;
  SmallPtrSet<SDNode*, 64> Visited;
  Worklist.push_back(DAG->getRoot().getNode());
  Visited.insert(DAG->getRoot().getNode());
  
  while (!Worklist.empty()) {
    SDNode *NI = Worklist.pop_back_val();
    
    // Add all operands to the worklist unless they've already been added.
    for (unsigned i = 0, e = NI->getNumOperands(); i != e; ++i)
      if (Visited.insert(NI->getOperand(i).getNode()))
        Worklist.push_back(NI->getOperand(i).getNode());
  
    if (isPassiveNode(NI))  // Leaf node, e.g. a TargetImmediate.
      continue;
    
    // If this node has already been processed, stop now.
    if (NI->getNodeId() != -1) continue;
    
    SUnit *NodeSUnit = NewSUnit(NI);
    
    // See if anything is flagged to this node, if so, add them to flagged
    // nodes.  Nodes can have at most one flag input and one flag output.  Flags
    // are required to be the last operand and result of a node.
    
    // Scan up to find flagged preds.
    SDNode *N = NI;
    while (N->getNumOperands() &&
           N->getOperand(N->getNumOperands()-1).getValueType() == MVT::Flag) {
      N = N->getOperand(N->getNumOperands()-1).getNode();
      assert(N->getNodeId() == -1 && "Node already inserted!");
      N->setNodeId(NodeSUnit->NodeNum);
    }
    
    // Scan down to find any flagged succs.
    N = NI;
    while (N->getValueType(N->getNumValues()-1) == MVT::Flag) {
      SDValue FlagVal(N, N->getNumValues()-1);
      
      // There are either zero or one users of the Flag result.
      bool HasFlagUse = false;
      for (SDNode::use_iterator UI = N->use_begin(), E = N->use_end(); 
           UI != E; ++UI)
        if (FlagVal.isOperandOf(*UI)) {
          HasFlagUse = true;
          assert(N->getNodeId() == -1 && "Node already inserted!");
          N->setNodeId(NodeSUnit->NodeNum);
          N = *UI;
          break;
        }
      if (!HasFlagUse) break;
    }
    
    // If there are flag operands involved, N is now the bottom-most node
    // of the sequence of nodes that are flagged together.
    // Update the SUnit.
    NodeSUnit->setNode(N);
    assert(N->getNodeId() == -1 && "Node already inserted!");
    N->setNodeId(NodeSUnit->NodeNum);

    // Assign the Latency field of NodeSUnit using target-provided information.
    if (UnitLatencies)
      NodeSUnit->Latency = 1;
    else
      ComputeLatency(NodeSUnit);
  }
}