2 //***************************************************************************
7 // Encapsulate heuristics for instruction scheduling.
10 // Priority ordering rules:
11 // (1) Max delay, which is the order of the heap S.candsAsHeap.
12 // (2) Instruction that frees up a register.
13 // (3) Instruction that has the maximum number of dependent instructions.
14 // Note that rules 2 and 3 are only used if issue conflicts prevent
15 // choosing a higher priority instruction by rule 1.
18 // 7/30/01 - Vikram Adve - Created
19 //**************************************************************************/
21 #ifndef LLVM_CODEGEN_SCHEDPRIORITIES_H
22 #define LLVM_CODEGEN_SCHEDPRIORITIES_H
24 #include "SchedGraph.h"
25 #include "llvm/CodeGen/InstrScheduling.h"
26 #include "llvm/Analysis/LiveVar/MethodLiveVarInfo.h"
27 #include "llvm/Target/MachineSchedInfo.h"
28 #include "Support/CommandLine.h"
33 class SchedulingManager;
35 //---------------------------------------------------------------------------
36 // Debug option levels for instruction scheduling
38 enum SchedDebugLevel_t {
40 Sched_PrintMachineCode,
41 Sched_PrintSchedTrace,
42 Sched_PrintSchedGraphs,
45 extern cl::Enum<SchedDebugLevel_t> SchedDebugLevel;
47 //---------------------------------------------------------------------------
48 // Function: instrIsFeasible
51 // Used by the priority analysis to filter out instructions
52 // that are not feasible to issue in the current cycle.
53 // Should only be used during schedule construction..
54 //---------------------------------------------------------------------------
56 bool instrIsFeasible(const SchedulingManager &S, MachineOpCode opCode);
60 struct NodeDelayPair {
61 const SchedGraphNode* node;
63 NodeDelayPair(const SchedGraphNode* n, cycles_t d) : node(n), delay(d) {}
64 inline bool operator<(const NodeDelayPair& np) { return delay < np.delay; }
68 NDPLessThan(const NodeDelayPair* np1, const NodeDelayPair* np2)
70 return np1->delay < np2->delay;
73 class NodeHeap: public std::list<NodeDelayPair*>, public NonCopyable {
75 typedef std::list<NodeDelayPair*>::iterator iterator;
76 typedef std::list<NodeDelayPair*>::const_iterator const_iterator;
79 NodeHeap() : _size(0) {}
81 inline unsigned size() const { return _size; }
83 const SchedGraphNode* getNode (const_iterator i) const { return (*i)->node; }
84 cycles_t getDelay(const_iterator i) const { return (*i)->delay;}
86 inline void makeHeap() {
87 // make_heap(begin(), end(), NDPLessThan);
90 inline iterator findNode(const SchedGraphNode* node) {
91 for (iterator I=begin(); I != end(); ++I)
92 if (getNode(I) == node)
97 inline void removeNode (const SchedGraphNode* node) {
98 iterator ndpPtr = findNode(node);
107 void insert(const SchedGraphNode* node, cycles_t delay) {
108 NodeDelayPair* ndp = new NodeDelayPair(node, delay);
109 if (_size == 0 || front()->delay < delay)
114 for ( ; I != end() && getDelay(I) >= delay; ++I)
116 std::list<NodeDelayPair*>::insert(I, ndp);
125 class SchedPriorities: public NonCopyable {
127 /*ctor*/ SchedPriorities (const Method* method,
128 const SchedGraph* _graph);
130 // This must be called before scheduling begins.
133 cycles_t getTime () const { return curTime; }
134 cycles_t getEarliestReadyTime () const { return earliestReadyTime; }
135 unsigned getNumReady () const { return candsAsHeap.size(); }
136 bool nodeIsReady (const SchedGraphNode* node) const {
137 return (candsAsSet.find(node) != candsAsSet.end());
140 void issuedReadyNodeAt (cycles_t curTime,
141 const SchedGraphNode* node);
143 void insertReady (const SchedGraphNode* node);
145 void updateTime (cycles_t /*unused*/);
147 const SchedGraphNode* getNextHighest (const SchedulingManager& S,
149 // choose next highest priority instr
152 typedef NodeHeap::iterator candIndex;
156 const SchedGraph* graph;
157 MethodLiveVarInfo methodLiveVarInfo;
158 std::hash_map<const MachineInstr*, bool> lastUseMap;
159 std::vector<cycles_t> nodeDelayVec;
160 std::vector<cycles_t> earliestForNode;
161 cycles_t earliestReadyTime;
162 NodeHeap candsAsHeap; // candidate nodes, ready to go
163 std::hash_set<const SchedGraphNode*> candsAsSet;//same entries as candsAsHeap,
164 // but as set for fast lookup
165 std::vector<candIndex> mcands; // holds pointers into cands
166 candIndex nextToTry; // next cand after the last
167 // one tried in this cycle
169 int chooseByRule1 (std::vector<candIndex>& mcands);
170 int chooseByRule2 (std::vector<candIndex>& mcands);
171 int chooseByRule3 (std::vector<candIndex>& mcands);
173 void findSetWithMaxDelay (std::vector<candIndex>& mcands,
174 const SchedulingManager& S);
176 void computeDelays (const SchedGraph* graph);
178 void initializeReadyHeap (const SchedGraph* graph);
180 bool instructionHasLastUse (MethodLiveVarInfo& methodLiveVarInfo,
181 const SchedGraphNode* graphNode);
183 // NOTE: The next two return references to the actual vector entries.
185 cycles_t& getNodeDelayRef (const SchedGraphNode* node) {
186 assert(node->getNodeId() < nodeDelayVec.size());
187 return nodeDelayVec[node->getNodeId()];
189 cycles_t& getEarliestForNodeRef (const SchedGraphNode* node) {
190 assert(node->getNodeId() < earliestForNode.size());
191 return earliestForNode[node->getNodeId()];
196 inline void SchedPriorities::updateTime(cycles_t c) {
198 nextToTry = candsAsHeap.begin();
202 inline std::ostream &operator<<(std::ostream &os, const NodeDelayPair* nd) {
203 return os << "Delay for node " << nd->node->getNodeId()
204 << " = " << (long)nd->delay << "\n";