llvm-6502/include/llvm/CodeGen/SchedPriorities.h
2001-08-28 23:06:49 +00:00

226 lines
6.5 KiB
C++

/* -*-C++-*-
****************************************************************************
* File:
* SchedPriorities.h
*
* Purpose:
* Encapsulate heuristics for instruction scheduling.
*
* Strategy:
* Priority ordering rules:
* (1) Max delay, which is the order of the heap S.candsAsHeap.
* (2) Instruction that frees up a register.
* (3) Instruction that has the maximum number of dependent instructions.
* Note that rules 2 and 3 are only used if issue conflicts prevent
* choosing a higher priority instruction by rule 1.
*
* History:
* 7/30/01 - Vikram Adve - Created
***************************************************************************/
#ifndef LLVM_CODEGEN_SCHEDPRIORITIES_H
#define LLVM_CODEGEN_SCHEDPRIORITIES_H
//************************** System Include Files **************************/
#include <hash_map>
#include <list>
#include <vector>
#include <algorithm>
//*************************** User Include Files ***************************/
#include "llvm/CFG.h" // just for graph iterators
#include "llvm/Support/NonCopyable.h"
#include "llvm/Support/HashExtras.h"
#include "llvm/Analysis/LiveVar/MethodLiveVarInfo.h"
#include "llvm/CodeGen/SchedGraph.h"
#include "llvm/CodeGen/InstrScheduling.h"
//************************* Opaque Declarations ****************************/
class Method;
class MachineInstr;
class SchedulingManager;
/******************** Exported Data Types and Constants ********************/
//*********************** Public Class Declarations ************************/
struct NodeDelayPair {
const SchedGraphNode* node;
cycles_t delay;
NodeDelayPair(const SchedGraphNode* n, cycles_t d) : node(n), delay(d) {}
inline bool operator< (const NodeDelayPair& np) { return delay < np.delay; }
};
inline bool
NDPLessThan(const NodeDelayPair* np1, const NodeDelayPair* np2)
{
return (np1->delay < np2->delay);
}
class NodeHeap: public list<NodeDelayPair*>, public NonCopyable {
public:
typedef list<NodeDelayPair*>::iterator iterator;
typedef list<NodeDelayPair*>::const_iterator const_iterator;
public:
/*ctor*/ NodeHeap () : list<NodeDelayPair*>(), _size(0) {}
/*dtor*/ ~NodeHeap () {}
inline unsigned int size () const { return _size; }
const SchedGraphNode* getNode (const_iterator i) const { return (*i)->node; }
cycles_t getDelay(const_iterator i) const { return (*i)->delay;}
inline void makeHeap() {
// make_heap(begin(), end(), NDPLessThan);
}
inline iterator findNode(const SchedGraphNode* node) {
for (iterator I=begin(); I != end(); ++I)
if (getNode(I) == node)
return I;
return end();
}
inline void removeNode (const SchedGraphNode* node) {
iterator ndpPtr = findNode(node);
if (ndpPtr != end())
{
delete *ndpPtr;
erase(ndpPtr);
--_size;
}
};
void insert(const SchedGraphNode* node, cycles_t delay) {
NodeDelayPair* ndp = new NodeDelayPair(node, delay);
if (_size == 0 || front()->delay < delay)
push_front(ndp);
else
{
iterator I=begin();
for ( ; I != end() && getDelay(I) >= delay; ++I)
;
list<NodeDelayPair*>::insert(I, ndp);
}
_size++;
}
private:
unsigned int _size;
};
class SchedPriorities: public NonCopyable {
public:
/*ctor*/ SchedPriorities (const Method* method,
const SchedGraph* _graph);
// This must be called before scheduling begins.
void initialize ();
cycles_t getTime () const { return curTime; }
cycles_t getEarliestReadyTime () const { return earliestReadyTime; }
unsigned getNumReady () const { return candsAsHeap.size(); }
bool nodeIsReady (const SchedGraphNode* node) const {
return (candsAsSet.find(node) != candsAsSet.end());
}
void issuedReadyNodeAt (cycles_t curTime,
const SchedGraphNode* node);
void insertReady (const SchedGraphNode* node);
void updateTime (cycles_t /*unused*/);
const SchedGraphNode* getNextHighest (const SchedulingManager& S,
cycles_t curTime);
// choose next highest priority instr
private:
typedef NodeHeap::iterator candIndex;
private:
cycles_t curTime;
const SchedGraph* graph;
MethodLiveVarInfo methodLiveVarInfo;
hash_map<const MachineInstr*, bool> lastUseMap;
vector<cycles_t> nodeDelayVec;
vector<cycles_t> earliestForNode;
cycles_t earliestReadyTime;
NodeHeap candsAsHeap; // candidate nodes, ready to go
hash_set<const SchedGraphNode*> candsAsSet; // same entries as candsAsHeap,
// but as set for fast lookup
vector<candIndex> mcands; // holds pointers into cands
candIndex nextToTry; // next cand after the last
// one tried in this cycle
int chooseByRule1 (vector<candIndex>& mcands);
int chooseByRule2 (vector<candIndex>& mcands);
int chooseByRule3 (vector<candIndex>& mcands);
void findSetWithMaxDelay (vector<candIndex>& mcands,
const SchedulingManager& S);
void computeDelays (const SchedGraph* graph);
void initializeReadyHeap (const SchedGraph* graph);
bool instructionHasLastUse (MethodLiveVarInfo& methodLiveVarInfo,
const SchedGraphNode* graphNode);
// NOTE: The next two return references to the actual vector entries.
// Use with care.
cycles_t& getNodeDelayRef (const SchedGraphNode* node) {
assert(node->getNodeId() < nodeDelayVec.size());
return nodeDelayVec[node->getNodeId()];
}
cycles_t& getEarliestForNodeRef (const SchedGraphNode* node) {
assert(node->getNodeId() < earliestForNode.size());
return earliestForNode[node->getNodeId()];
}
};
inline void
SchedPriorities::insertReady(const SchedGraphNode* node)
{
candsAsHeap.insert(node, nodeDelayVec[node->getNodeId()]);
candsAsSet.insert(node);
mcands.clear(); // ensure reset choices is called before any more choices
earliestReadyTime = min(earliestReadyTime,
earliestForNode[node->getNodeId()]);
if (SchedDebugLevel >= Sched_PrintSchedTrace)
{
printIndent(2);
cout << "Cycle " << this->getTime() << ": "
<< " Node " << node->getNodeId() << " is ready; "
<< " Delay = " << this->getNodeDelayRef(node) << "; Instruction: "
<< endl;
printIndent(4);
cout << * node->getMachineInstr() << endl;
}
}
inline void
SchedPriorities::updateTime(cycles_t c)
{
curTime = c;
nextToTry = candsAsHeap.begin();
mcands.clear();
}
inline ostream& operator<< (ostream& os, const NodeDelayPair* nd) {
os << "Delay for node " << nd->node->getNodeId()
<< " = " << nd->delay << endl;
return os;
}
/***************************************************************************/
#endif