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+//===-- ScheduleDAG.cpp - Implement a trivial DAG scheduler ---------------===//
+//
+// The LLVM Compiler Infrastructure
+//
+// This file was developed by James M. Laskey and is distributed under the
+// University of Illinois Open Source License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This implements a simple two pass scheduler. The first pass attempts to push
+// backward any lengthy instructions and critical paths. The second pass packs
+// instructions into semi-optimal time slots.
+//
+//===----------------------------------------------------------------------===//
+
+#define DEBUG_TYPE "sched"
+#include "llvm/CodeGen/MachineConstantPool.h"
+#include "llvm/CodeGen/MachineFunction.h"
+#include "llvm/CodeGen/SelectionDAGISel.h"
+#include "llvm/CodeGen/SelectionDAG.h"
+#include "llvm/CodeGen/SSARegMap.h"
+#include "llvm/Target/TargetMachine.h"
+#include "llvm/Target/TargetInstrInfo.h"
+#include "llvm/Target/TargetLowering.h"
+#include "llvm/Support/CommandLine.h"
+#include "llvm/Support/Debug.h"
+#include <iostream>
+using namespace llvm;
+
+namespace {
+ // Style of scheduling to use.
+ enum ScheduleChoices {
+ noScheduling,
+ simpleScheduling,
+ };
+} // namespace
+
+cl::opt<ScheduleChoices> ScheduleStyle("sched",
+ cl::desc("Choose scheduling style"),
+ cl::init(noScheduling),
+ cl::values(
+ clEnumValN(noScheduling, "none",
+ "Trivial emission with no analysis"),
+ clEnumValN(simpleScheduling, "simple",
+ "Minimize critical path and maximize processor utilization"),
+ clEnumValEnd));
+
+
+#ifndef NDEBUG
+static cl::opt<bool>
+ViewDAGs("view-sched-dags", cl::Hidden,
+ cl::desc("Pop up a window to show sched dags as they are processed"));
+#else
+static const bool ViewDAGs = 0;
+#endif
+
+namespace {
+//===----------------------------------------------------------------------===//
+///
+/// BitsIterator - Provides iteration through individual bits in a bit vector.
+///
+template<class T>
+class BitsIterator {
+private:
+ T Bits; // Bits left to iterate through
+
+public:
+ /// Ctor.
+ BitsIterator(T Initial) : Bits(Initial) {}
+
+ /// Next - Returns the next bit set or zero if exhausted.
+ inline T Next() {
+ // Get the rightmost bit set
+ T Result = Bits & -Bits;
+ // Remove from rest
+ Bits &= ~Result;
+ // Return single bit or zero
+ return Result;
+ }
+};
+
+//===----------------------------------------------------------------------===//
+
+
+//===----------------------------------------------------------------------===//
+///
+/// ResourceTally - Manages the use of resources over time intervals. Each
+/// item (slot) in the tally vector represents the resources used at a given
+/// moment. A bit set to 1 indicates that a resource is in use, otherwise
+/// available. An assumption is made that the tally is large enough to schedule
+/// all current instructions (asserts otherwise.)
+///
+template<class T>
+class ResourceTally {
+private:
+ std::vector<T> Tally; // Resources used per slot
+ typedef typename std::vector<T>::iterator Iter;
+ // Tally iterator
+
+ /// AllInUse - Test to see if all of the resources in the slot are busy (set.)
+ inline bool AllInUse(Iter Cursor, unsigned ResourceSet) {
+ return (*Cursor & ResourceSet) == ResourceSet;
+ }
+
+ /// Skip - Skip over slots that use all of the specified resource (all are
+ /// set.)
+ Iter Skip(Iter Cursor, unsigned ResourceSet) {
+ assert(ResourceSet && "At least one resource bit needs to bet set");
+
+ // Continue to the end
+ while (true) {
+ // Break out if one of the resource bits is not set
+ if (!AllInUse(Cursor, ResourceSet)) return Cursor;
+ // Try next slot
+ Cursor++;
+ assert(Cursor < Tally.end() && "Tally is not large enough for schedule");
+ }
+ }
+
+ /// FindSlots - Starting from Begin, locate N consecutive slots where at least
+ /// one of the resource bits is available. Returns the address of first slot.
+ Iter FindSlots(Iter Begin, unsigned N, unsigned ResourceSet,
+ unsigned &Resource) {
+ // Track position
+ Iter Cursor = Begin;
+
+ // Try all possible slots forward
+ while (true) {
+ // Skip full slots
+ Cursor = Skip(Cursor, ResourceSet);
+ // Determine end of interval
+ Iter End = Cursor + N;
+ assert(End <= Tally.end() && "Tally is not large enough for schedule");
+
+ // Iterate thru each resource
+ BitsIterator<T> Resources(ResourceSet & ~*Cursor);
+ while (unsigned Res = Resources.Next()) {
+ // Check if resource is available for next N slots
+ // Break out if resource is busy
+ Iter Interval = Cursor;
+ for (; Interval < End && !(*Interval & Res); Interval++) {}
+
+ // If available for interval, return where and which resource
+ if (Interval == End) {
+ Resource = Res;
+ return Cursor;
+ }
+ // Otherwise, check if worth checking other resources
+ if (AllInUse(Interval, ResourceSet)) {
+ // Start looking beyond interval
+ Cursor = Interval;
+ break;
+ }
+ }
+ Cursor++;
+ }
+ }
+
+ /// Reserve - Mark busy (set) the specified N slots.
+ void Reserve(Iter Begin, unsigned N, unsigned Resource) {
+ // Determine end of interval
+ Iter End = Begin + N;
+ assert(End <= Tally.end() && "Tally is not large enough for schedule");
+
+ // Set resource bit in each slot
+ for (; Begin < End; Begin++)
+ *Begin |= Resource;
+ }
+
+public:
+ /// Initialize - Resize and zero the tally to the specified number of time
+ /// slots.
+ inline void Initialize(unsigned N) {
+ Tally.assign(N, 0); // Initialize tally to all zeros.
+ }
+
+ // FindAndReserve - Locate and mark busy (set) N bits started at slot I, using
+ // ResourceSet for choices.
+ unsigned FindAndReserve(unsigned I, unsigned N, unsigned ResourceSet) {
+ // Which resource used
+ unsigned Resource;
+ // Find slots for instruction.
+ Iter Where = FindSlots(Tally.begin() + I, N, ResourceSet, Resource);
+ // Reserve the slots
+ Reserve(Where, N, Resource);
+ // Return time slot (index)
+ return Where - Tally.begin();
+ }
+
+};
+//===----------------------------------------------------------------------===//
+
+// Forward
+class NodeInfo;
+typedef NodeInfo *NodeInfoPtr;
+typedef std::vector<NodeInfoPtr> NIVector;
+typedef std::vector<NodeInfoPtr>::iterator NIIterator;
+
+//===----------------------------------------------------------------------===//
+///
+/// Node group - This struct is used to manage flagged node groups.
+///
+class NodeGroup {
+private:
+ NIVector Members; // Group member nodes
+ int Pending; // Number of visits pending before
+ // adding to order
+
+public:
+ // Ctor.
+ NodeGroup() : Pending(0) {}
+
+ // Accessors
+ inline NodeInfo *getLeader() {
+ return Members.empty() ? NULL : Members.front();
+ }
+ inline int getPending() const { return Pending; }
+ inline void setPending(int P) { Pending = P; }
+ inline int addPending(int I) { return Pending += I; }
+
+ // Pass thru
+ inline bool group_empty() { return Members.empty(); }
+ inline NIIterator group_begin() { return Members.begin(); }
+ inline NIIterator group_end() { return Members.end(); }
+ inline void group_push_back(const NodeInfoPtr &NI) { Members.push_back(NI); }
+ inline NIIterator group_insert(NIIterator Pos, const NodeInfoPtr &NI) {
+ return Members.insert(Pos, NI);
+ }
+ inline void group_insert(NIIterator Pos, NIIterator First, NIIterator Last) {
+ Members.insert(Pos, First, Last);
+ }
+
+ static void Add(NodeInfo *D, NodeInfo *U);
+ static unsigned CountInternalUses(NodeInfo *D, NodeInfo *U);
+};
+//===----------------------------------------------------------------------===//
+
+
+//===----------------------------------------------------------------------===//
+///
+/// NodeInfo - This struct tracks information used to schedule the a node.
+///
+class NodeInfo {
+private:
+ int Pending; // Number of visits pending before
+ // adding to order
+public:
+ SDNode *Node; // DAG node
+ unsigned Latency; // Cycles to complete instruction
+ unsigned ResourceSet; // Bit vector of usable resources
+ bool IsCall; // Is function call
+ unsigned Slot; // Node's time slot
+ NodeGroup *Group; // Grouping information
+ unsigned VRBase; // Virtual register base
+#ifndef NDEBUG
+ unsigned Preorder; // Index before scheduling
+#endif
+
+ // Ctor.
+ NodeInfo(SDNode *N = NULL)
+ : Pending(0)
+ , Node(N)
+ , Latency(0)
+ , ResourceSet(0)
+ , IsCall(false)
+ , Slot(0)
+ , Group(NULL)
+ , VRBase(0)
+#ifndef NDEBUG
+ , Preorder(0)
+#endif
+ {}
+
+ // Accessors
+ inline bool isInGroup() const {
+ assert(!Group || !Group->group_empty() && "Group with no members");
+ return Group != NULL;
+ }
+ inline bool isGroupLeader() const {
+ return isInGroup() && Group->getLeader() == this;
+ }
+ inline int getPending() const {
+ return Group ? Group->getPending() : Pending;
+ }
+ inline void setPending(int P) {
+ if (Group) Group->setPending(P);
+ else Pending = P;
+ }
+ inline int addPending(int I) {
+ if (Group) return Group->addPending(I);
+ else return Pending += I;
+ }
+};
+//===----------------------------------------------------------------------===//
+
+
+//===----------------------------------------------------------------------===//
+///
+/// NodeGroupIterator - Iterates over all the nodes indicated by the node info.
+/// If the node is in a group then iterate over the members of the group,
+/// otherwise just the node info.
+///
+class NodeGroupIterator {
+private:
+ NodeInfo *NI; // Node info
+ NIIterator NGI; // Node group iterator
+ NIIterator NGE; // Node group iterator end
+
+public:
+ // Ctor.
+ NodeGroupIterator(NodeInfo *N) : NI(N) {
+ // If the node is in a group then set up the group iterator. Otherwise
+ // the group iterators will trip first time out.
+ if (N->isInGroup()) {
+ // get Group
+ NodeGroup *Group = NI->Group;
+ NGI = Group->group_begin();
+ NGE = Group->group_end();
+ // Prevent this node from being used (will be in members list
+ NI = NULL;
+ }
+ }
+
+ /// next - Return the next node info, otherwise NULL.
+ ///
+ NodeInfo *next() {
+ // If members list
+ if (NGI != NGE) return *NGI++;
+ // Use node as the result (may be NULL)
+ NodeInfo *Result = NI;
+ // Only use once
+ NI = NULL;
+ // Return node or NULL
+ return Result;
+ }
+};
+//===----------------------------------------------------------------------===//
+
+
+//===----------------------------------------------------------------------===//
+///
+/// NodeGroupOpIterator - Iterates over all the operands of a node. If the node
+/// is a member of a group, this iterates over all the operands of all the
+/// members of the group.
+///
+class NodeGroupOpIterator {
+private:
+ NodeInfo *NI; // Node containing operands
+ NodeGroupIterator GI; // Node group iterator
+ SDNode::op_iterator OI; // Operand iterator
+ SDNode::op_iterator OE; // Operand iterator end
+
+ /// CheckNode - Test if node has more operands. If not get the next node
+ /// skipping over nodes that have no operands.
+ void CheckNode() {
+ // Only if operands are exhausted first
+ while (OI == OE) {
+ // Get next node info
+ NodeInfo *NI = GI.next();
+ // Exit if nodes are exhausted
+ if (!NI) return;
+ // Get node itself
+ SDNode *Node = NI->Node;
+ // Set up the operand iterators
+ OI = Node->op_begin();
+ OE = Node->op_end();
+ }
+ }
+
+public:
+ // Ctor.
+ NodeGroupOpIterator(NodeInfo *N) : NI(N), GI(N) {}
+
+ /// isEnd - Returns true when not more operands are available.
+ ///
+ inline bool isEnd() { CheckNode(); return OI == OE; }
+
+ /// next - Returns the next available operand.
+ ///
+ inline SDOperand next() {
+ assert(OI != OE && "Not checking for end of NodeGroupOpIterator correctly");
+ return *OI++;
+ }
+};
+//===----------------------------------------------------------------------===//
+
+
+//===----------------------------------------------------------------------===//
+///
+/// SimpleSched - Simple two pass scheduler.
+///
+class SimpleSched {
+private:
+ // TODO - get ResourceSet from TII
+ enum {
+ RSInteger = 0x3, // Two integer units
+ RSFloat = 0xC, // Two float units
+ RSLoadStore = 0x30, // Two load store units
+ RSBranch = 0x400, // One branch unit
+ RSOther = 0 // Processing unit independent
+ };
+
+ MachineBasicBlock *BB; // Current basic block
+ SelectionDAG &DAG; // DAG of the current basic block
+ const TargetMachine &TM; // Target processor
+ const TargetInstrInfo &TII; // Target instruction information
+ const MRegisterInfo &MRI; // Target processor register information
+ SSARegMap *RegMap; // Virtual/real register map
+ MachineConstantPool *ConstPool; // Target constant pool
+ unsigned NodeCount; // Number of nodes in DAG
+ NodeInfo *Info; // Info for nodes being scheduled
+ std::map<SDNode *, NodeInfo *> Map; // Map nodes to info
+ NIVector Ordering; // Emit ordering of nodes
+ ResourceTally<unsigned> Tally; // Resource usage tally
+ unsigned NSlots; // Total latency
+ static const unsigned NotFound = ~0U; // Search marker
+
+public:
+
+ // Ctor.
+ SimpleSched(SelectionDAG &D, MachineBasicBlock *bb)
+ : BB(bb), DAG(D), TM(D.getTarget()), TII(*TM.getInstrInfo()),
+ MRI(*TM.getRegisterInfo()), RegMap(BB->getParent()->getSSARegMap()),
+ ConstPool(BB->getParent()->getConstantPool()),
+ NodeCount(0), Info(NULL), Map(), Tally(), NSlots(0) {
+ assert(&TII && "Target doesn't provide instr info?");
+ assert(&MRI && "Target doesn't provide register info?");
+ }
+
+ // Run - perform scheduling.
+ MachineBasicBlock *Run() {
+ Schedule();
+ return BB;
+ }
+
+private:
+ /// getNI - Returns the node info for the specified node.
+ ///
+ inline NodeInfo *getNI(SDNode *Node) { return Map[Node]; }
+
+ /// getVR - Returns the virtual register number of the node.
+ ///
+ inline unsigned getVR(SDOperand Op) {
+ NodeInfo *NI = getNI(Op.Val);
+ assert(NI->VRBase != 0 && "Node emitted out of order - late");
+ return NI->VRBase + Op.ResNo;
+ }
+
+ static bool isFlagDefiner(SDNode *A);
+ static bool isFlagUser(SDNode *A);
+ static bool isDefiner(NodeInfo *A, NodeInfo *B);
+ static bool isPassiveNode(SDNode *Node);
+ void IncludeNode(NodeInfo *NI);
+ void VisitAll();
+ void Schedule();
+ void IdentifyGroups();
+ void GatherSchedulingInfo();
+ void PrepareNodeInfo();
+ bool isStrongDependency(NodeInfo *A, NodeInfo *B);
+ bool isWeakDependency(NodeInfo *A, NodeInfo *B);
+ void ScheduleBackward();
+ void ScheduleForward();
+ void EmitAll();
+ void EmitNode(NodeInfo *NI);
+ static unsigned CountResults(SDNode *Node);
+ static unsigned CountOperands(SDNode *Node);
+ unsigned CreateVirtualRegisters(MachineInstr *MI,
+ unsigned NumResults,
+ const TargetInstrDescriptor &II);
+
+ void printChanges(unsigned Index);
+ void printSI(std::ostream &O, NodeInfo *NI) const;
+ void print(std::ostream &O) const;
+ inline void dump(const char *tag) const { std::cerr << tag; dump(); }
+ void dump() const;
+};
+//===----------------------------------------------------------------------===//
+
+} // namespace
+
+//===----------------------------------------------------------------------===//
+
+
+//===----------------------------------------------------------------------===//
+/// Add - Adds a definer and user pair to a node group.
+///
+void NodeGroup::Add(NodeInfo *D, NodeInfo *U) {
+ // Get current groups
+ NodeGroup *DGroup = D->Group;
+ NodeGroup *UGroup = U->Group;
+ // If both are members of groups
+ if (DGroup && UGroup) {
+ // There may have been another edge connecting
+ if (DGroup == UGroup) return;
+ // Add the pending users count
+ DGroup->addPending(UGroup->getPending());
+ // For each member of the users group
+ NodeGroupIterator UNGI(U);
+ while (NodeInfo *UNI = UNGI.next() ) {
+ // Change the group
+ UNI->Group = DGroup;
+ // For each member of the definers group
+ NodeGroupIterator DNGI(D);
+ while (NodeInfo *DNI = DNGI.next() ) {
+ // Remove internal edges
+ DGroup->addPending(-CountInternalUses(DNI, UNI));
+ }
+ }
+ // Merge the two lists
+ DGroup->group_insert(DGroup->group_end(),
+ UGroup->group_begin(), UGroup->group_end());
+ } else if (DGroup) {
+ // Make user member of definers group
+ U->Group = DGroup;
+ // Add users uses to definers group pending
+ DGroup->addPending(U->Node->use_size());
+ // For each member of the definers group
+ NodeGroupIterator DNGI(D);
+ while (NodeInfo *DNI = DNGI.next() ) {
+ // Remove internal edges
+ DGroup->addPending(-CountInternalUses(DNI, U));
+ }
+ DGroup->group_push_back(U);
+ } else if (UGroup) {
+ // Make definer member of users group
+ D->Group = UGroup;
+ // Add definers uses to users group pending
+ UGroup->addPending(D->Node->use_size());
+ // For each member of the users group
+ NodeGroupIterator UNGI(U);
+ while (NodeInfo *UNI = UNGI.next() ) {
+ // Remove internal edges
+ UGroup->addPending(-CountInternalUses(D, UNI));
+ }
+ UGroup->group_insert(UGroup->group_begin(), D);
+ } else {
+ D->Group = U->Group = DGroup = new NodeGroup();
+ DGroup->addPending(D->Node->use_size() + U->Node->use_size() -
+ CountInternalUses(D, U));
+ DGroup->group_push_back(D);
+ DGroup->group_push_back(U);
+ }
+}
+
+/// CountInternalUses - Returns the number of edges between the two nodes.
+///
+unsigned NodeGroup::CountInternalUses(NodeInfo *D, NodeInfo *U) {
+ unsigned N = 0;
+ for (unsigned M = U->Node->getNumOperands(); 0 < M--;) {
+ SDOperand Op = U->Node->getOperand(M);
+ if (Op.Val == D->Node) N++;
+ }
+
+ return N;
+}
+//===----------------------------------------------------------------------===//
+
+
+//===----------------------------------------------------------------------===//
+/// isFlagDefiner - Returns true if the node defines a flag result.
+bool SimpleSched::isFlagDefiner(SDNode *A) {
+ unsigned N = A->getNumValues();
+ return N && A->getValueType(N - 1) == MVT::Flag;
+}
+
+/// isFlagUser - Returns true if the node uses a flag result.
+///
+bool SimpleSched::isFlagUser(SDNode *A) {
+ unsigned N = A->getNumOperands();
+ return N && A->getOperand(N - 1).getValueType() == MVT::Flag;
+}
+
+/// isDefiner - Return true if node A is a definer for B.
+///
+bool SimpleSched::isDefiner(NodeInfo *A, NodeInfo *B) {
+ // While there are A nodes
+ NodeGroupIterator NII(A);
+ while (NodeInfo *NI = NII.next()) {
+ // Extract node
+ SDNode *Node = NI->Node;
+ // While there operands in nodes of B
+ NodeGroupOpIterator NGOI(B);
+ while (!NGOI.isEnd()) {
+ SDOperand Op = NGOI.next();
+ // If node from A defines a node in B
+ if (Node == Op.Val) return true;
+ }
+ }
+ return false;
+}
+
+/// isPassiveNode - Return true if the node is a non-scheduled leaf.
+///
+bool SimpleSched::isPassiveNode(SDNode *Node) {
+ if (isa<ConstantSDNode>(Node)) return true;
+ if (isa<RegisterSDNode>(Node)) return true;
+ if (isa<GlobalAddressSDNode>(Node)) return true;
+ if (isa<BasicBlockSDNode>(Node)) return true;
+ if (isa<FrameIndexSDNode>(Node)) return true;
+ if (isa<ConstantPoolSDNode>(Node)) return true;
+ if (isa<ExternalSymbolSDNode>(Node)) return true;
+ return false;
+}
+
+/// IncludeNode - Add node to NodeInfo vector.
+///
+void SimpleSched::IncludeNode(NodeInfo *NI) {
+ // Get node
+ SDNode *Node = NI->Node;
+ // Ignore entry node
+if (Node->getOpcode() == ISD::EntryToken) return;
+ // Check current count for node
+ int Count = NI->getPending();
+ // If the node is already in list
+ if (Count < 0) return;
+ // Decrement count to indicate a visit
+ Count--;
+ // If count has gone to zero then add node to list
+ if (!Count) {
+ // Add node
+ if (NI->isInGroup()) {
+ Ordering.push_back(NI->Group->getLeader());
+ } else {
+ Ordering.push_back(NI);
+ }
+ // indicate node has been added
+ Count--;
+ }
+ // Mark as visited with new count
+ NI->setPending(Count);
+}
+
+/// VisitAll - Visit each node breadth-wise to produce an initial ordering.
+/// Note that the ordering in the Nodes vector is reversed.
+void SimpleSched::VisitAll() {
+ // Add first element to list
+ Ordering.push_back(getNI(DAG.getRoot().Val));
+
+ // Iterate through all nodes that have been added
+ for (unsigned i = 0; i < Ordering.size(); i++) { // note: size() varies
+ // Visit all operands
+ NodeGroupOpIterator NGI(Ordering[i]);
+ while (!NGI.isEnd()) {
+ // Get next operand
+ SDOperand Op = NGI.next();
+ // Get node
+ SDNode *Node = Op.Val;
+ // Ignore passive nodes
+ if (isPassiveNode(Node)) continue;
+ // Check out node
+ IncludeNode(getNI(Node));
+ }
+ }
+
+ // Add entry node last (IncludeNode filters entry nodes)
+ if (DAG.getEntryNode().Val != DAG.getRoot().Val)
+ Ordering.push_back(getNI(DAG.getEntryNode().Val));
+
+ // FIXME - Reverse the order
+ for (unsigned i = 0, N = Ordering.size(), Half = N >> 1; i < Half; i++) {
+ unsigned j = N - i - 1;
+ NodeInfo *tmp = Ordering[i];
+ Ordering[i] = Ordering[j];
+ Ordering[j] = tmp;
+ }
+}
+
+/// IdentifyGroups - Put flagged nodes into groups.
+///
+void SimpleSched::IdentifyGroups() {
+ for (unsigned i = 0, N = NodeCount; i < N; i++) {
+ NodeInfo* NI = &Info[i];
+ SDNode *Node = NI->Node;
+
+ // For each operand (in reverse to only look at flags)
+ for (unsigned N = Node->getNumOperands(); 0 < N--;) {
+ // Get operand
+ SDOperand Op = Node->getOperand(N);
+ // No more flags to walk
+ if (Op.getValueType() != MVT::Flag) break;
+ // Add to node group
+ NodeGroup::Add(getNI(Op.Val), NI);
+ }
+ }
+}
+
+/// GatherSchedulingInfo - Get latency and resource information about each node.
+///
+void SimpleSched::GatherSchedulingInfo() {
+ // Track if groups are present
+ bool AreGroups = false;
+
+ // For each node
+ for (unsigned i = 0, N = NodeCount; i < N; i++) {
+ // Get node info
+ NodeInfo* NI = &Info[i];
+ SDNode *Node = NI->Node;
+
+ // Test for groups
+ if (NI->isInGroup()) AreGroups = true;
+
+ // FIXME: Pretend by using value type to choose metrics
+ MVT::ValueType VT = Node->getValueType(0);
+
+ // If machine opcode
+ if (Node->isTargetOpcode()) {
+ MachineOpCode TOpc = Node->getTargetOpcode();
+ // FIXME: This is an ugly (but temporary!) hack to test the scheduler
+ // before we have real target info.
+ // FIXME NI->Latency = std::max(1, TII.maxLatency(TOpc));
+ // FIXME NI->ResourceSet = TII.resources(TOpc);
+ if (TII.isCall(TOpc)) {
+ NI->ResourceSet = RSBranch;
+ NI->Latency = 40;
+ NI->IsCall = true;
+ } else if (TII.isLoad(TOpc)) {
+ NI->ResourceSet = RSLoadStore;
+ NI->Latency = 5;
+ } else if (TII.isStore(TOpc)) {
+ NI->ResourceSet = RSLoadStore;
+ NI->Latency = 2;
+ } else if (MVT::isInteger(VT)) {
+ NI->ResourceSet = RSInteger;
+ NI->Latency = 2;
+ } else if (MVT::isFloatingPoint(VT)) {
+ NI->ResourceSet = RSFloat;
+ NI->Latency = 3;
+ } else {
+ NI->ResourceSet = RSOther;
+ NI->Latency = 0;
+ }
+ } else {
+ if (MVT::isInteger(VT)) {
+ NI->ResourceSet = RSInteger;
+ NI->Latency = 2;
+ } else if (MVT::isFloatingPoint(VT)) {
+ NI->ResourceSet = RSFloat;
+ NI->Latency = 3;
+ } else {
+ NI->ResourceSet = RSOther;
+ NI->Latency = 0;
+ }
+ }
+
+ // Add one slot for the instruction itself
+ NI->Latency++;
+
+ // Sum up all the latencies for max tally size
+ NSlots += NI->Latency;
+ }
+
+ // Unify metrics if in a group
+ if (AreGroups) {
+ for (unsigned i = 0, N = NodeCount; i < N; i++) {
+ NodeInfo* NI = &Info[i];
+
+ if (NI->isGroupLeader()) {
+ NodeGroup *Group = NI->Group;
+ unsigned Latency = 0;
+ unsigned MaxLat = 0;
+ unsigned ResourceSet = 0;
+ bool IsCall = false;
+
+ for (NIIterator NGI = Group->group_begin(), NGE = Group->group_end();
+ NGI != NGE; NGI++) {
+ NodeInfo* NGNI = *NGI;
+ Latency += NGNI->Latency;
+ IsCall = IsCall || NGNI->IsCall;
+
+ if (MaxLat < NGNI->Latency) {
+ MaxLat = NGNI->Latency;
+ ResourceSet = NGNI->ResourceSet;
+ }
+
+ NGNI->Latency = 0;
+ NGNI->ResourceSet = 0;
+ NGNI->IsCall = false;
+ }
+
+ NI->Latency = Latency;
+ NI->ResourceSet = ResourceSet;
+ NI->IsCall = IsCall;
+ }
+ }
+ }
+}
+
+/// PrepareNodeInfo - Set up the basic minimum node info for scheduling.
+///
+void SimpleSched::PrepareNodeInfo() {
+ // Allocate node information
+ Info = new NodeInfo[NodeCount];
+ // Get base of all nodes table
+ SelectionDAG::allnodes_iterator AllNodes = DAG.allnodes_begin();
+
+ // For each node being scheduled
+ for (unsigned i = 0, N = NodeCount; i < N; i++) {
+ // Get next node from DAG all nodes table
+ SDNode *Node = AllNodes[i];
+ // Fast reference to node schedule info
+ NodeInfo* NI = &Info[i];
+ // Set up map
+ Map[Node] = NI;
+ // Set node
+ NI->Node = Node;
+ // Set pending visit count
+ NI->setPending(Node->use_size());
+ }
+}
+
+/// isStrongDependency - Return true if node A has results used by node B.
+/// I.E., B must wait for latency of A.
+bool SimpleSched::isStrongDependency(NodeInfo *A, NodeInfo *B) {
+ // If A defines for B then it's a strong dependency
+ return isDefiner(A, B);
+}
+
+/// isWeakDependency Return true if node A produces a result that will
+/// conflict with operands of B. It is assumed that we have called
+/// isStrongDependency prior.
+bool SimpleSched::isWeakDependency(NodeInfo *A, NodeInfo *B) {
+ // TODO check for conflicting real registers and aliases
+#if 0 // FIXME - Since we are in SSA form and not checking register aliasing
+ return A->Node->getOpcode() == ISD::EntryToken || isStrongDependency(B, A);
+#else
+ return A->Node->getOpcode() == ISD::EntryToken;
+#endif
+}
+
+/// ScheduleBackward - Schedule instructions so that any long latency
+/// instructions and the critical path get pushed back in time. Time is run in
+/// reverse to allow code reuse of the Tally and eliminate the overhead of
+/// biasing every slot indices against NSlots.
+void SimpleSched::ScheduleBackward() {
+ // Size and clear the resource tally
+ Tally.Initialize(NSlots);
+ // Get number of nodes to schedule
+ unsigned N = Ordering.size();
+
+ // For each node being scheduled
+ for (unsigned i = N; 0 < i--;) {
+ NodeInfo *NI = Ordering[i];
+ // Track insertion
+ unsigned Slot = NotFound;
+
+ // Compare against those previously scheduled nodes
+ unsigned j = i + 1;
+ for (; j < N; j++) {
+ // Get following instruction
+ NodeInfo *Other = Ordering[j];
+
+ // Check dependency against previously inserted nodes
+ if (isStrongDependency(NI, Other)) {
+ Slot = Other->Slot + Other->Latency;
+ break;
+ } else if (isWeakDependency(NI, Other)) {
+ Slot = Other->Slot;
+ break;
+ }
+ }
+
+ // If independent of others (or first entry)
+ if (Slot == NotFound) Slot = 0;
+
+ // Find a slot where the needed resources are available
+ if (NI->ResourceSet)
+ Slot = Tally.FindAndReserve(Slot, NI->Latency, NI->ResourceSet);
+
+ // Set node slot
+ NI->Slot = Slot;
+
+ // Insert sort based on slot
+ j = i + 1;
+ for (; j < N; j++) {
+ // Get following instruction
+ NodeInfo *Other = Ordering[j];
+ // Should we look further (remember slots are in reverse time)
+ if (Slot >= Other->Slot) break;
+ // Shuffle other into ordering
+ Ordering[j - 1] = Other;
+ }
+ // Insert node in proper slot
+ if (j != i + 1) Ordering[j - 1] = NI;
+ }
+}
+
+/// ScheduleForward - Schedule instructions to maximize packing.
+///
+void SimpleSched::ScheduleForward() {
+ // Size and clear the resource tally
+ Tally.Initialize(NSlots);
+ // Get number of nodes to schedule
+ unsigned N = Ordering.size();
+
+ // For each node being scheduled
+ for (unsigned i = 0; i < N; i++) {
+ NodeInfo *NI = Ordering[i];
+ // Track insertion
+ unsigned Slot = NotFound;
+
+ // Compare against those previously scheduled nodes
+ unsigned j = i;
+ for (; 0 < j--;) {
+ // Get following instruction
+ NodeInfo *Other = Ordering[j];
+
+ // Check dependency against previously inserted nodes
+ if (isStrongDependency(Other, NI)) {
+ Slot = Other->Slot + Other->Latency;
+ break;
+ } else if (Other->IsCall || isWeakDependency(Other, NI)) {
+ Slot = Other->Slot;
+ break;
+ }
+ }
+
+ // If independent of others (or first entry)
+ if (Slot == NotFound) Slot = 0;
+
+ // Find a slot where the needed resources are available
+ if (NI->ResourceSet)
+ Slot = Tally.FindAndReserve(Slot, NI->Latency, NI->ResourceSet);
+
+ // Set node slot
+ NI->Slot = Slot;
+
+ // Insert sort based on slot
+ j = i;
+ for (; 0 < j--;) {
+ // Get prior instruction
+ NodeInfo *Other = Ordering[j];
+ // Should we look further
+ if (Slot >= Other->Slot) break;
+ // Shuffle other into ordering
+ Ordering[j + 1] = Other;
+ }
+ // Insert node in proper slot
+ if (j != i) Ordering[j + 1] = NI;
+ }
+}
+
+/// EmitAll - Emit all nodes in schedule sorted order.
+///
+void SimpleSched::EmitAll() {
+ // For each node in the ordering
+ for (unsigned i = 0, N = Ordering.size(); i < N; i++) {
+ // Get the scheduling info
+ NodeInfo *NI = Ordering[i];
+ // Iterate through nodes
+ NodeGroupIterator NGI(Ordering[i]);
+ if (NI->isInGroup()) {
+ if (NI->isGroupLeader()) {
+ NodeGroupIterator NGI(Ordering[i]);
+ while (NodeInfo *NI = NGI.next()) EmitNode(NI);
+ }
+ } else {
+ EmitNode(NI);
+ }
+ }
+}
+
+/// CountResults - The results of target nodes have register or immediate
+/// operands first, then an optional chain, and optional flag operands (which do
+/// not go into the machine instrs.)
+unsigned SimpleSched::CountResults(SDNode *Node) {
+ unsigned N = Node->getNumValues();
+ while (N && Node->getValueType(N - 1) == MVT::Flag)
+ --N;
+ if (N && Node->getValueType(N - 1) == MVT::Other)
+ --N; // Skip over chain result.
+ return N;
+}
+
+/// CountOperands The inputs to target nodes have any actual inputs first,
+/// followed by an optional chain operand, then flag operands. Compute the
+/// number of actual operands that will go into the machine instr.
+unsigned SimpleSched::CountOperands(SDNode *Node) {
+ unsigned N = Node->getNumOperands();
+ while (N && Node->getOperand(N - 1).getValueType() == MVT::Flag)
+ --N;
+ if (N && Node->getOperand(N - 1).getValueType() == MVT::Other)
+ --N; // Ignore chain if it exists.
+ return N;
+}
+
+/// CreateVirtualRegisters - Add result register values for things that are
+/// defined by this instruction.
+unsigned SimpleSched::CreateVirtualRegisters(MachineInstr *MI,
+ unsigned NumResults,
+ const TargetInstrDescriptor &II) {
+ // Create the result registers for this node and add the result regs to
+ // the machine instruction.
+ const TargetOperandInfo *OpInfo = II.OpInfo;
+ unsigned ResultReg = RegMap->createVirtualRegister(OpInfo[0].RegClass);
+ MI->addRegOperand(ResultReg, MachineOperand::Def);
+ for (unsigned i = 1; i != NumResults; ++i) {
+ assert(OpInfo[i].RegClass && "Isn't a register operand!");
+ MI->addRegOperand(RegMap->createVirtualRegister(OpInfo[i].RegClass),
+ MachineOperand::Def);
+ }
+ return ResultReg;
+}
+
+/// EmitNode - Generate machine code for an node and needed dependencies.
+///
+void SimpleSched::EmitNode(NodeInfo *NI) {
+ unsigned VRBase = 0; // First virtual register for node
+ SDNode *Node = NI->Node;
+
+ // If machine instruction
+ if (Node->isTargetOpcode()) {
+ unsigned Opc = Node->getTargetOpcode();
+ const TargetInstrDescriptor &II = TII.get(Opc);
+
+ unsigned NumResults = CountResults(Node);
+ unsigned NodeOperands = CountOperands(Node);
+ unsigned NumMIOperands = NodeOperands + NumResults;
+#ifndef NDEBUG
+ assert((unsigned(II.numOperands) == NumMIOperands || II.numOperands == -1)&&
+ "#operands for dag node doesn't match .td file!");
+#endif
+
+ // Create the new machine instruction.
+ MachineInstr *MI = new MachineInstr(Opc, NumMIOperands, true, true);
+
+ // Add result register values for things that are defined by this
+ // instruction.
+
+ // If the node is only used by a CopyToReg and the dest reg is a vreg, use
+ // the CopyToReg'd destination register instead of creating a new vreg.
+ if (NumResults == 1) {
+ for (SDNode::use_iterator UI = Node->use_begin(), E = Node->use_end();
+ UI != E; ++UI) {
+ SDNode *Use = *UI;
+ if (Use->getOpcode() == ISD::CopyToReg &&
+ Use->getOperand(2).Val == Node) {
+ unsigned Reg = cast<RegisterSDNode>(Use->getOperand(1))->getReg();
+ if (MRegisterInfo::isVirtualRegister(Reg)) {
+ VRBase = Reg;
+ MI->addRegOperand(Reg, MachineOperand::Def);
+ break;
+ }
+ }
+ }
+ }
+
+ // Otherwise, create new virtual registers.
+ if (NumResults && VRBase == 0)
+ VRBase = CreateVirtualRegisters(MI, NumResults, II);
+
+ // Emit all of the actual operands of this instruction, adding them to the
+ // instruction as appropriate.
+ for (unsigned i = 0; i != NodeOperands; ++i) {
+ if (Node->getOperand(i).isTargetOpcode()) {
+ // Note that this case is redundant with the final else block, but we
+ // include it because it is the most common and it makes the logic
+ // simpler here.
+ assert(Node->getOperand(i).getValueType() != MVT::Other &&
+ Node->getOperand(i).getValueType() != MVT::Flag &&
+ "Chain and flag operands should occur at end of operand list!");
+
+ // Get/emit the operand.
+ unsigned VReg = getVR(Node->getOperand(i));
+ MI->addRegOperand(VReg, MachineOperand::Use);
+
+ // Verify that it is right.
+ assert(MRegisterInfo::isVirtualRegister(VReg) && "Not a vreg?");
+ assert(II.OpInfo[i+NumResults].RegClass &&
+ "Don't have operand info for this instruction!");
+ assert(RegMap->getRegClass(VReg) == II.OpInfo[i+NumResults].RegClass &&
+ "Register class of operand and regclass of use don't agree!");
+ } else if (ConstantSDNode *C =
+ dyn_cast<ConstantSDNode>(Node->getOperand(i))) {
+ MI->addZeroExtImm64Operand(C->getValue());
+ } else if (RegisterSDNode*R =
+ dyn_cast<RegisterSDNode>(Node->getOperand(i))) {
+ MI->addRegOperand(R->getReg(), MachineOperand::Use);
+ } else if (GlobalAddressSDNode *TGA =
+ dyn_cast<GlobalAddressSDNode>(Node->getOperand(i))) {
+ MI->addGlobalAddressOperand(TGA->getGlobal(), false, 0);
+ } else if (BasicBlockSDNode *BB =
+ dyn_cast<BasicBlockSDNode>(Node->getOperand(i))) {
+ MI->addMachineBasicBlockOperand(BB->getBasicBlock());
+ } else if (FrameIndexSDNode *FI =
+ dyn_cast<FrameIndexSDNode>(Node->getOperand(i))) {
+ MI->addFrameIndexOperand(FI->getIndex());
+ } else if (ConstantPoolSDNode *CP =
+ dyn_cast<ConstantPoolSDNode>(Node->getOperand(i))) {
+ unsigned Idx = ConstPool->getConstantPoolIndex(CP->get());
+ MI->addConstantPoolIndexOperand(Idx);
+ } else if (ExternalSymbolSDNode *ES =
+ dyn_cast<ExternalSymbolSDNode>(Node->getOperand(i))) {
+ MI->addExternalSymbolOperand(ES->getSymbol(), false);
+ } else {
+ assert(Node->getOperand(i).getValueType() != MVT::Other &&
+ Node->getOperand(i).getValueType() != MVT::Flag &&
+ "Chain and flag operands should occur at end of operand list!");
+ unsigned VReg = getVR(Node->getOperand(i));
+ MI->addRegOperand(VReg, MachineOperand::Use);
+
+ // Verify that it is right.
+ assert(MRegisterInfo::isVirtualRegister(VReg) && "Not a vreg?");
+ assert(II.OpInfo[i+NumResults].RegClass &&
+ "Don't have operand info for this instruction!");
+ assert(RegMap->getRegClass(VReg) == II.OpInfo[i+NumResults].RegClass &&
+ "Register class of operand and regclass of use don't agree!");
+ }
+ }
+
+ // Now that we have emitted all operands, emit this instruction itself.
+ if ((II.Flags & M_USES_CUSTOM_DAG_SCHED_INSERTION) == 0) {
+ BB->insert(BB->end(), MI);
+ } else {
+ // Insert this instruction into the end of the basic block, potentially
+ // taking some custom action.
+ BB = DAG.getTargetLoweringInfo().InsertAtEndOfBasicBlock(MI, BB);
+ }
+ } else {
+ switch (Node->getOpcode()) {
+ default:
+ Node->dump();
+ assert(0 && "This target-independent node should have been selected!");
+ case ISD::EntryToken: // fall thru
+ case ISD::TokenFactor:
+ break;
+ case ISD::CopyToReg: {
+ unsigned InReg = getVR(Node->getOperand(2));
+ unsigned DestReg = cast<RegisterSDNode>(Node->getOperand(1))->getReg();
+ if (InReg != DestReg) // Coallesced away the copy?
+ MRI.copyRegToReg(*BB, BB->end(), DestReg, InReg,
+ RegMap->getRegClass(InReg));
+ break;
+ }
+ case ISD::CopyFromReg: {
+ unsigned SrcReg = cast<RegisterSDNode>(Node->getOperand(1))->getReg();
+ if (MRegisterInfo::isVirtualRegister(SrcReg)) {
+ VRBase = SrcReg; // Just use the input register directly!
+ break;
+ }
+
+ // If the node is only used by a CopyToReg and the dest reg is a vreg, use
+ // the CopyToReg'd destination register instead of creating a new vreg.
+ for (SDNode::use_iterator UI = Node->use_begin(), E = Node->use_end();
+ UI != E; ++UI) {
+ SDNode *Use = *UI;
+ if (Use->getOpcode() == ISD::CopyToReg &&
+ Use->getOperand(2).Val == Node) {
+ unsigned DestReg = cast<RegisterSDNode>(Use->getOperand(1))->getReg();
+ if (MRegisterInfo::isVirtualRegister(DestReg)) {
+ VRBase = DestReg;
+ break;
+ }
+ }
+ }
+
+ // Figure out the register class to create for the destreg.
+ const TargetRegisterClass *TRC = 0;
+ if (VRBase) {
+ TRC = RegMap->getRegClass(VRBase);
+ } else {
+
+ // Pick the register class of the right type that contains this physreg.
+ for (MRegisterInfo::regclass_iterator I = MRI.regclass_begin(),
+ E = MRI.regclass_end(); I != E; ++I)
+ if ((*I)->getType() == Node->getValueType(0) &&
+ (*I)->contains(SrcReg)) {
+ TRC = *I;
+ break;
+ }
+ assert(TRC && "Couldn't find register class for reg copy!");
+
+ // Create the reg, emit the copy.
+ VRBase = RegMap->createVirtualRegister(TRC);
+ }
+ MRI.copyRegToReg(*BB, BB->end(), VRBase, SrcReg, TRC);
+ break;
+ }
+ }
+ }
+
+ assert(NI->VRBase == 0 && "Node emitted out of order - early");
+ NI->VRBase = VRBase;
+}
+
+/// Schedule - Order nodes according to selected style.
+///
+void SimpleSched::Schedule() {
+ // Number the nodes
+ NodeCount = DAG.allnodes_size();
+ // Set up minimum info for scheduling.
+ PrepareNodeInfo();
+ // Construct node groups for flagged nodes
+ IdentifyGroups();
+ // Breadth first walk of DAG
+ VisitAll();
+
+#ifndef NDEBUG
+ static unsigned Count = 0;
+ Count++;
+ for (unsigned i = 0, N = Ordering.size(); i < N; i++) {
+ NodeInfo *NI = Ordering[i];
+ NI->Preorder = i;
+ }
+#endif
+
+ // Don't waste time if is only entry and return
+ if (NodeCount > 3 && ScheduleStyle != noScheduling) {
+ // Get latency and resource requirements
+ GatherSchedulingInfo();
+
+ // Push back long instructions and critical path
+ ScheduleBackward();
+
+ // Pack instructions to maximize resource utilization
+ ScheduleForward();
+ }
+
+ DEBUG(printChanges(Count));
+
+ // Emit in scheduled order
+ EmitAll();
+}
+
+/// printChanges - Hilight changes in order caused by scheduling.
+///
+void SimpleSched::printChanges(unsigned Index) {
+#ifndef NDEBUG
+ // Get the ordered node count
+ unsigned N = Ordering.size();
+ // Determine if any changes
+ unsigned i = 0;
+ for (; i < N; i++) {
+ NodeInfo *NI = Ordering[i];
+ if (NI->Preorder != i) break;
+ }
+
+ if (i < N) {
+ std::cerr << Index << ". New Ordering\n";
+
+ for (i = 0; i < N; i++) {
+ NodeInfo *NI = Ordering[i];
+ std::cerr << " " << NI->Preorder << ". ";
+ printSI(std::cerr, NI);
+ std::cerr << "\n";
+ if (NI->isGroupLeader()) {
+ NodeGroup *Group = NI->Group;
+ for (NIIterator NII = Group->group_begin(), E = Group->group_end();
+ NII != E; NII++) {
+ std::cerr << " ";
+ printSI(std::cerr, *NII);
+ std::cerr << "\n";
+ }
+ }
+ }
+ } else {
+ std::cerr << Index << ". No Changes\n";
+ }
+#endif
+}
+
+/// printSI - Print schedule info.
+///
+void SimpleSched::printSI(std::ostream &O, NodeInfo *NI) const {
+#ifndef NDEBUG
+ SDNode *Node = NI->Node;
+ O << " "
+ << std::hex << Node << std::dec
+ << ", RS=" << NI->ResourceSet
+ << ", Lat=" << NI->Latency
+ << ", Slot=" << NI->Slot
+ << ", ARITY=(" << Node->getNumOperands() << ","
+ << Node->getNumValues() << ")"
+ << " " << Node->getOperationName(&DAG);
+ if (isFlagDefiner(Node)) O << "<#";
+ if (isFlagUser(Node)) O << ">#";
+#endif
+}
+
+/// print - Print ordering to specified output stream.
+///
+void SimpleSched::print(std::ostream &O) const {
+#ifndef NDEBUG
+ using namespace std;
+ O << "Ordering\n";
+ for (unsigned i = 0, N = Ordering.size(); i < N; i++) {
+ NodeInfo *NI = Ordering[i];
+ printSI(O, NI);
+ O << "\n";
+ if (NI->isGroupLeader()) {
+ NodeGroup *Group = NI->Group;
+ for (NIIterator NII = Group->group_begin(), E = Group->group_end();
+ NII != E; NII++) {
+ O << " ";
+ printSI(O, *NII);
+ O << "\n";
+ }
+ }
+ }
+#endif
+}
+
+/// dump - Print ordering to std::cerr.
+///
+void SimpleSched::dump() const {
+ print(std::cerr);
+}
+//===----------------------------------------------------------------------===//
+
+
+//===----------------------------------------------------------------------===//
+/// ScheduleAndEmitDAG - Pick a safe ordering and emit instructions for each
+/// target node in the graph.
+void SelectionDAGISel::ScheduleAndEmitDAG(SelectionDAG &SD) {
+ if (ViewDAGs) SD.viewGraph();
+ BB = SimpleSched(SD, BB).Run();
+}
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