//===-- LegalizeTypes.cpp - Common code for DAG type legalizer ------------===// // // The LLVM Compiler Infrastructure // // This file is distributed under the University of Illinois Open Source // License. See LICENSE.TXT for details. // //===----------------------------------------------------------------------===// // // This file implements the SelectionDAG::LegalizeTypes method. It transforms // an arbitrary well-formed SelectionDAG to only consist of legal types. This // is common code shared among the LegalizeTypes*.cpp files. // //===----------------------------------------------------------------------===// #include "LegalizeTypes.h" #include "llvm/CallingConv.h" #include "llvm/Constants.h" #include "llvm/DerivedTypes.h" #include "llvm/Support/CommandLine.h" #include "llvm/Support/MathExtras.h" using namespace llvm; #ifndef NDEBUG static cl::opt ViewLegalizeTypesDAGs("view-legalize-types-dags", cl::Hidden, cl::desc("Pop up a window to show dags before legalize types")); #else static const bool ViewLegalizeTypesDAGs = 0; #endif /// 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. void DAGTypeLegalizer::run() { // 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()); // 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(SDOperand()); // Walk all nodes in the graph, assigning them a NodeID of 'ReadyToProcess' // (and remembering them) if they are leaves and assigning 'NewNode' 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(NewNode); } } // Now that we have a set of nodes to process, handle them all. while (!Worklist.empty()) { SDNode *N = Worklist.back(); Worklist.pop_back(); assert(N->getNodeId() == ReadyToProcess && "Node should be ready if on worklist!"); // Scan the values produced by the node, checking to see if any result // types are illegal. unsigned i = 0; unsigned NumResults = N->getNumValues(); do { MVT ResultVT = N->getValueType(i); switch (getTypeAction(ResultVT)) { default: assert(false && "Unknown action!"); case Legal: break; case Promote: PromoteResult(N, i); goto NodeDone; case Expand: ExpandResult(N, i); goto NodeDone; case FloatToInt: FloatToIntResult(N, i); goto NodeDone; case Scalarize: ScalarizeResult(N, i); goto NodeDone; case Split: SplitResult(N, i); goto NodeDone; } } while (++i < NumResults); // Scan the operand list for the node, handling any nodes with operands that // are illegal. { unsigned NumOperands = N->getNumOperands(); bool NeedsRevisit = false; for (i = 0; i != NumOperands; ++i) { MVT OpVT = N->getOperand(i).getValueType(); switch (getTypeAction(OpVT)) { default: assert(false && "Unknown action!"); case Legal: continue; case Promote: NeedsRevisit = PromoteOperand(N, i); break; case Expand: NeedsRevisit = ExpandOperand(N, i); break; case FloatToInt: NeedsRevisit = FloatToIntOperand(N, i); break; case Scalarize: NeedsRevisit = ScalarizeOperand(N, i); break; case Split: NeedsRevisit = SplitOperand(N, i); break; } break; } // If the node needs revisiting, don't add all users to the worklist etc. if (NeedsRevisit) continue; if (i == NumOperands) DEBUG(cerr << "Legally typed node: "; N->dump(&DAG); cerr << "\n"); } NodeDone: // If we reach here, the node was processed, potentially creating new nodes. // Mark it as processed and add its users to the worklist as appropriate. N->setNodeId(Processed); for (SDNode::use_iterator UI = N->use_begin(), E = N->use_end(); UI != E; ++UI) { SDNode *User = UI->getUser(); int NodeID = User->getNodeId(); assert(NodeID != ReadyToProcess && NodeID != Processed && "Invalid node id for user of unprocessed node!"); // This node has two options: it can either be a new node or its Node ID // may be a count of the number of operands it has that are not ready. if (NodeID > 0) { User->setNodeId(NodeID-1); // If this was the last use it was waiting on, add it to the ready list. if (NodeID-1 == ReadyToProcess) Worklist.push_back(User); continue; } // Otherwise, this node is new: this is the first operand of it that // became ready. Its new NodeID is the number of operands it has minus 1 // (as this node is now processed). assert(NodeID == NewNode && "Unknown node ID!"); User->setNodeId(User->getNumOperands()-1); // If the node only has a single operand, it is now ready. if (User->getNumOperands() == 1) Worklist.push_back(User); } } // If the root changed (e.g. it was a dead load, update the root). DAG.setRoot(Dummy.getValue()); //DAG.viewGraph(); // Remove dead nodes. This is important to do for cleanliness but also before // the checking loop below. Implicit folding by the DAG.getNode operators can // cause unreachable nodes to be around with their flags set to new. DAG.RemoveDeadNodes(); // In a debug build, scan all the nodes to make sure we found them all. This // ensures that there are no cycles and that everything got processed. #ifndef NDEBUG for (SelectionDAG::allnodes_iterator I = DAG.allnodes_begin(), E = DAG.allnodes_end(); I != E; ++I) { bool Failed = false; // Check that all result types are legal. for (unsigned i = 0, NumVals = I->getNumValues(); i < NumVals; ++i) if (!isTypeLegal(I->getValueType(i))) { cerr << "Result type " << i << " illegal!\n"; Failed = true; } // Check that all operand types are legal. for (unsigned i = 0, NumOps = I->getNumOperands(); i < NumOps; ++i) if (!isTypeLegal(I->getOperand(i).getValueType())) { cerr << "Operand type " << i << " illegal!\n"; Failed = true; } if (I->getNodeId() != Processed) { if (I->getNodeId() == NewNode) cerr << "New node not 'noticed'?\n"; else if (I->getNodeId() > 0) cerr << "Operand not processed?\n"; else if (I->getNodeId() == ReadyToProcess) cerr << "Not added to worklist?\n"; Failed = true; } if (Failed) { I->dump(&DAG); cerr << "\n"; abort(); } } #endif } /// AnalyzeNewNode - The specified node is the root of a subtree of potentially /// new nodes. Correct any processed operands (this may change the node) and /// calculate the NodeId. void DAGTypeLegalizer::AnalyzeNewNode(SDNode *&N) { // If this was an existing node that is already done, we're done. if (N->getNodeId() != NewNode) return; // Okay, we know that this node is new. Recursively walk all of its operands // to see if they are new also. The depth of this walk is bounded by the size // of the new tree that was constructed (usually 2-3 nodes), so we don't worry // about revisiting of nodes. // // As we walk the operands, keep track of the number of nodes that are // processed. If non-zero, this will become the new nodeid of this node. // Already processed operands may need to be remapped to the node that // replaced them, which can result in our node changing. Since remapping // is rare, the code tries to minimize overhead in the non-remapping case. SmallVector NewOps; unsigned NumProcessed = 0; for (unsigned i = 0, e = N->getNumOperands(); i != e; ++i) { SDOperand OrigOp = N->getOperand(i); SDOperand Op = OrigOp; if (Op.Val->getNodeId() == Processed) RemapNode(Op); if (Op.Val->getNodeId() == NewNode) AnalyzeNewNode(Op.Val); else if (Op.Val->getNodeId() == Processed) ++NumProcessed; if (!NewOps.empty()) { // Some previous operand changed. Add this one to the list. NewOps.push_back(Op); } else if (Op != OrigOp) { // This is the first operand to change - add all operands so far. for (unsigned j = 0; j < i; ++j) NewOps.push_back(N->getOperand(j)); NewOps.push_back(Op); } } // Some operands changed - update the node. if (!NewOps.empty()) N = DAG.UpdateNodeOperands(SDOperand(N, 0), &NewOps[0], NewOps.size()).Val; N->setNodeId(N->getNumOperands()-NumProcessed); if (N->getNodeId() == ReadyToProcess) Worklist.push_back(N); } namespace { /// NodeUpdateListener - This class is a DAGUpdateListener that listens for /// updates to nodes and recomputes their ready state. class VISIBILITY_HIDDEN NodeUpdateListener : public SelectionDAG::DAGUpdateListener { DAGTypeLegalizer &DTL; public: NodeUpdateListener(DAGTypeLegalizer &dtl) : DTL(dtl) {} virtual void NodeDeleted(SDNode *N, SDNode *E) { assert(N->getNodeId() != DAGTypeLegalizer::Processed && N->getNodeId() != DAGTypeLegalizer::ReadyToProcess && "RAUW deleted processed node!"); // It is possible, though rare, for the deleted node N to occur as a // target in a map, so note the replacement N -> E in ReplacedNodes. assert(E && "Node not replaced?"); for (unsigned i = 0, e = E->getNumValues(); i != e; ++i) DTL.NoteReplacement(SDOperand(N, i), SDOperand(E, i)); } virtual void NodeUpdated(SDNode *N) { // Node updates can mean pretty much anything. It is possible that an // operand was set to something already processed (f.e.) in which case // this node could become ready. Recompute its flags. assert(N->getNodeId() != DAGTypeLegalizer::Processed && N->getNodeId() != DAGTypeLegalizer::ReadyToProcess && "RAUW updated processed node!"); DTL.ReanalyzeNode(N); } }; } /// ReplaceValueWith - The specified value was legalized to the specified other /// value. If they are different, update the DAG and NodeIDs replacing any uses /// of From to use To instead. void DAGTypeLegalizer::ReplaceValueWith(SDOperand From, SDOperand To) { if (From == To) return; // If expansion produced new nodes, make sure they are properly marked. AnalyzeNewNode(To.Val); // Anything that used the old node should now use the new one. Note that this // can potentially cause recursive merging. NodeUpdateListener NUL(*this); DAG.ReplaceAllUsesOfValueWith(From, To, &NUL); // The old node may still be present in a map like ExpandedNodes or // PromotedNodes. Inform maps about the replacement. NoteReplacement(From, To); } /// ReplaceNodeWith - Replace uses of the 'from' node's results with the 'to' /// node's results. The from and to node must define identical result types. void DAGTypeLegalizer::ReplaceNodeWith(SDNode *From, SDNode *To) { if (From == To) return; // If expansion produced new nodes, make sure they are properly marked. AnalyzeNewNode(To); assert(From->getNumValues() == To->getNumValues() && "Node results don't match"); // Anything that used the old node should now use the new one. Note that this // can potentially cause recursive merging. NodeUpdateListener NUL(*this); DAG.ReplaceAllUsesWith(From, To, &NUL); // The old node may still be present in a map like ExpandedNodes or // PromotedNodes. Inform maps about the replacement. for (unsigned i = 0, e = From->getNumValues(); i != e; ++i) { assert(From->getValueType(i) == To->getValueType(i) && "Node results don't match"); NoteReplacement(SDOperand(From, i), SDOperand(To, i)); } } /// RemapNode - If the specified value was already legalized to another value, /// replace it by that value. void DAGTypeLegalizer::RemapNode(SDOperand &N) { DenseMap::iterator I = ReplacedNodes.find(N); if (I != ReplacedNodes.end()) { // Use path compression to speed up future lookups if values get multiply // replaced with other values. RemapNode(I->second); N = I->second; } } /// ExpungeNode - If this is a deleted value that was kept around to speed up /// remapping, remove it globally now. The only map that can have a deleted /// node as a source is ReplacedNodes. Other maps can have deleted nodes as /// targets, but since their looked-up values are always immediately remapped /// using RemapNode, resulting in a not-deleted node, this is harmless as long /// as ReplacedNodes/RemapNode always performs correct mappings. The mapping /// will always be correct as long as ExpungeNode is called on the source when /// adding a new node to ReplacedNodes, and called on the target when adding /// a new node to any map. void DAGTypeLegalizer::ExpungeNode(SDOperand N) { SDOperand Replacement = N; RemapNode(Replacement); if (Replacement != N) { // Remove N from all maps - this is expensive but extremely rare. ReplacedNodes.erase(N); for (DenseMap::iterator I = ReplacedNodes.begin(), E = ReplacedNodes.end(); I != E; ++I) { if (I->second == N) I->second = Replacement; } for (DenseMap::iterator I = PromotedNodes.begin(), E = PromotedNodes.end(); I != E; ++I) { assert(I->first != N); if (I->second == N) I->second = Replacement; } for (DenseMap::iterator I = FloatToIntedNodes.begin(), E = FloatToIntedNodes.end(); I != E; ++I) { assert(I->first != N); if (I->second == N) I->second = Replacement; } for (DenseMap::iterator I = ScalarizedNodes.begin(), E = ScalarizedNodes.end(); I != E; ++I) { assert(I->first != N); if (I->second == N) I->second = Replacement; } for (DenseMap >::iterator I = ExpandedNodes.begin(), E = ExpandedNodes.end(); I != E; ++I) { assert(I->first != N); if (I->second.first == N) I->second.first = Replacement; if (I->second.second == N) I->second.second = Replacement; } for (DenseMap >::iterator I = SplitNodes.begin(), E = SplitNodes.end(); I != E; ++I) { assert(I->first != N); if (I->second.first == N) I->second.first = Replacement; if (I->second.second == N) I->second.second = Replacement; } } } void DAGTypeLegalizer::SetPromotedOp(SDOperand Op, SDOperand Result) { ExpungeNode(Result); AnalyzeNewNode(Result.Val); SDOperand &OpEntry = PromotedNodes[Op]; assert(OpEntry.Val == 0 && "Node is already promoted!"); OpEntry = Result; } void DAGTypeLegalizer::SetIntegerOp(SDOperand Op, SDOperand Result) { ExpungeNode(Result); AnalyzeNewNode(Result.Val); SDOperand &OpEntry = FloatToIntedNodes[Op]; assert(OpEntry.Val == 0 && "Node is already converted to integer!"); OpEntry = Result; } void DAGTypeLegalizer::SetScalarizedOp(SDOperand Op, SDOperand Result) { ExpungeNode(Result); AnalyzeNewNode(Result.Val); SDOperand &OpEntry = ScalarizedNodes[Op]; assert(OpEntry.Val == 0 && "Node is already scalarized!"); OpEntry = Result; } void DAGTypeLegalizer::GetExpandedOp(SDOperand Op, SDOperand &Lo, SDOperand &Hi) { std::pair &Entry = ExpandedNodes[Op]; RemapNode(Entry.first); RemapNode(Entry.second); assert(Entry.first.Val && "Operand isn't expanded"); Lo = Entry.first; Hi = Entry.second; } void DAGTypeLegalizer::SetExpandedOp(SDOperand Op, SDOperand Lo, SDOperand Hi) { ExpungeNode(Lo); ExpungeNode(Hi); // Lo/Hi may have been newly allocated, if so, add nodeid's as relevant. AnalyzeNewNode(Lo.Val); AnalyzeNewNode(Hi.Val); // Remember that this is the result of the node. std::pair &Entry = ExpandedNodes[Op]; assert(Entry.first.Val == 0 && "Node already expanded"); Entry.first = Lo; Entry.second = Hi; } void DAGTypeLegalizer::GetSplitOp(SDOperand Op, SDOperand &Lo, SDOperand &Hi) { std::pair &Entry = SplitNodes[Op]; RemapNode(Entry.first); RemapNode(Entry.second); assert(Entry.first.Val && "Operand isn't split"); Lo = Entry.first; Hi = Entry.second; } void DAGTypeLegalizer::SetSplitOp(SDOperand Op, SDOperand Lo, SDOperand Hi) { ExpungeNode(Lo); ExpungeNode(Hi); // Lo/Hi may have been newly allocated, if so, add nodeid's as relevant. AnalyzeNewNode(Lo.Val); AnalyzeNewNode(Hi.Val); // Remember that this is the result of the node. std::pair &Entry = SplitNodes[Op]; assert(Entry.first.Val == 0 && "Node already split"); Entry.first = Lo; Entry.second = Hi; } /// BitConvertToInteger - Convert to an integer of the same size. SDOperand DAGTypeLegalizer::BitConvertToInteger(SDOperand Op) { unsigned BitWidth = Op.getValueType().getSizeInBits(); return DAG.getNode(ISD::BIT_CONVERT, MVT::getIntegerVT(BitWidth), Op); } SDOperand DAGTypeLegalizer::CreateStackStoreLoad(SDOperand Op, MVT DestVT) { // Create the stack frame object. SDOperand FIPtr = DAG.CreateStackTemporary(DestVT); // Emit a store to the stack slot. SDOperand Store = DAG.getStore(DAG.getEntryNode(), Op, FIPtr, NULL, 0); // Result is a load from the stack slot. return DAG.getLoad(DestVT, Store, FIPtr, NULL, 0); } /// JoinIntegers - Build an integer with low bits Lo and high bits Hi. SDOperand DAGTypeLegalizer::JoinIntegers(SDOperand Lo, SDOperand Hi) { MVT LVT = Lo.getValueType(); MVT HVT = Hi.getValueType(); MVT NVT = MVT::getIntegerVT(LVT.getSizeInBits() + HVT.getSizeInBits()); Lo = DAG.getNode(ISD::ZERO_EXTEND, NVT, Lo); Hi = DAG.getNode(ISD::ANY_EXTEND, NVT, Hi); Hi = DAG.getNode(ISD::SHL, NVT, Hi, DAG.getConstant(LVT.getSizeInBits(), TLI.getShiftAmountTy())); return DAG.getNode(ISD::OR, NVT, Lo, Hi); } /// SplitInteger - Return the lower LoVT bits of Op in Lo and the upper HiVT /// bits in Hi. void DAGTypeLegalizer::SplitInteger(SDOperand Op, MVT LoVT, MVT HiVT, SDOperand &Lo, SDOperand &Hi) { assert(LoVT.getSizeInBits() + HiVT.getSizeInBits() == Op.getValueType().getSizeInBits() && "Invalid integer splitting!"); Lo = DAG.getNode(ISD::TRUNCATE, LoVT, Op); Hi = DAG.getNode(ISD::SRL, Op.getValueType(), Op, DAG.getConstant(LoVT.getSizeInBits(), TLI.getShiftAmountTy())); Hi = DAG.getNode(ISD::TRUNCATE, HiVT, Hi); } /// SplitInteger - Return the lower and upper halves of Op's bits in a value type /// half the size of Op's. void DAGTypeLegalizer::SplitInteger(SDOperand Op, SDOperand &Lo, SDOperand &Hi) { MVT HalfVT = MVT::getIntegerVT(Op.getValueType().getSizeInBits()/2); SplitInteger(Op, HalfVT, HalfVT, Lo, Hi); } /// MakeLibCall - Generate a libcall taking the given operands as arguments and /// returning a result of type RetVT. SDOperand DAGTypeLegalizer::MakeLibCall(RTLIB::Libcall LC, MVT RetVT, const SDOperand *Ops, unsigned NumOps, bool isSigned) { TargetLowering::ArgListTy Args; Args.reserve(NumOps); TargetLowering::ArgListEntry Entry; for (unsigned i = 0; i != NumOps; ++i) { Entry.Node = Ops[i]; Entry.Ty = Entry.Node.getValueType().getTypeForMVT(); Entry.isSExt = isSigned; Entry.isZExt = !isSigned; Args.push_back(Entry); } SDOperand Callee = DAG.getExternalSymbol(TLI.getLibcallName(LC), TLI.getPointerTy()); const Type *RetTy = RetVT.getTypeForMVT(); std::pair CallInfo = TLI.LowerCallTo(DAG.getEntryNode(), RetTy, isSigned, !isSigned, false, CallingConv::C, false, Callee, Args, DAG); return CallInfo.first; } SDOperand DAGTypeLegalizer::GetVectorElementPointer(SDOperand VecPtr, MVT EltVT, SDOperand Index) { // Make sure the index type is big enough to compute in. if (Index.getValueType().bitsGT(TLI.getPointerTy())) Index = DAG.getNode(ISD::TRUNCATE, TLI.getPointerTy(), Index); else Index = DAG.getNode(ISD::ZERO_EXTEND, TLI.getPointerTy(), Index); // Calculate the element offset and add it to the pointer. unsigned EltSize = EltVT.getSizeInBits() / 8; // FIXME: should be ABI size. Index = DAG.getNode(ISD::MUL, Index.getValueType(), Index, DAG.getConstant(EltSize, Index.getValueType())); return DAG.getNode(ISD::ADD, Index.getValueType(), Index, VecPtr); } //===----------------------------------------------------------------------===// // Entry Point //===----------------------------------------------------------------------===// /// LegalizeTypes - This transforms the SelectionDAG into a SelectionDAG that /// only uses types natively supported by the target. /// /// Note that this is an involved process that may invalidate pointers into /// the graph. void SelectionDAG::LegalizeTypes() { if (ViewLegalizeTypesDAGs) viewGraph(); DAGTypeLegalizer(*this).run(); }