#include "Support/Debug.h"
#include "Support/Statistic.h"
#include "Support/STLExtras.h"
-#include "LiveIntervals.h"
+#include "LiveIntervalAnalysis.h"
#include "PhysRegTracker.h"
#include "VirtRegMap.h"
#include <algorithm>
#include <cmath>
-#include <iostream>
#include <set>
+#include <queue>
using namespace llvm;
const TargetMachine* tm_;
const MRegisterInfo* mri_;
LiveIntervals* li_;
- typedef std::list<LiveInterval*> IntervalPtrs;
- IntervalPtrs unhandled_, fixed_, active_, inactive_, handled_;
-
+ typedef std::vector<LiveInterval*> IntervalPtrs;
+ IntervalPtrs handled_, fixed_, active_, inactive_;
+ typedef std::priority_queue<LiveInterval*,
+ IntervalPtrs,
+ greater_ptr<LiveInterval> > IntervalHeap;
+ IntervalHeap unhandled_;
std::auto_ptr<PhysRegTracker> prt_;
std::auto_ptr<VirtRegMap> vrm_;
std::auto_ptr<Spiller> spiller_;
/// initIntervalSets - initializa the four interval sets:
/// unhandled, fixed, active and inactive
- void initIntervalSets(LiveIntervals::Intervals& li);
+ void initIntervalSets();
/// processActiveIntervals - expire old intervals and move
/// non-overlapping ones to the incative list
- void processActiveIntervals(IntervalPtrs::value_type cur);
+ void processActiveIntervals(LiveInterval* cur);
/// processInactiveIntervals - expire old intervals and move
/// overlapping ones to the active list
- void processInactiveIntervals(IntervalPtrs::value_type cur);
+ void processInactiveIntervals(LiveInterval* cur);
/// updateSpillWeights - updates the spill weights of the
/// specifed physical register and its weight
/// assignRegOrStackSlotAtInterval - assign a register if one
/// is available, or spill.
- void assignRegOrStackSlotAtInterval(IntervalPtrs::value_type cur);
+ void assignRegOrStackSlotAtInterval(LiveInterval* cur);
///
/// register handling helpers
/// getFreePhysReg - return a free physical register for this
/// virtual register interval if we have one, otherwise return
/// 0
- unsigned getFreePhysReg(IntervalPtrs::value_type cur);
+ unsigned getFreePhysReg(LiveInterval* cur);
/// assignVirt2StackSlot - assigns this virtual register to a
/// stack slot. returns the stack slot
int assignVirt2StackSlot(unsigned virtReg);
- void printIntervals(const char* const str,
- RA::IntervalPtrs::const_iterator i,
- RA::IntervalPtrs::const_iterator e) const {
+ template <typename ItTy>
+ void printIntervals(const char* const str, ItTy i, ItTy e) const {
if (str) std::cerr << str << " intervals:\n";
for (; i != e; ++i) {
std::cerr << "\t" << **i << " -> ";
std::cerr << mri_->getName(reg) << '\n';
}
}
-
-// void verifyAssignment() const {
-// for (Virt2PhysMap::const_iterator i = v2pMap_.begin(),
-// e = v2pMap_.end(); i != e; ++i)
-// for (Virt2PhysMap::const_iterator i2 = next(i); i2 != e; ++i2)
-// if (MRegisterInfo::isVirtualRegister(i->second) &&
-// (i->second == i2->second ||
-// mri_->areAliases(i->second, i2->second))) {
-// const Interval
-// &in = li_->getInterval(i->second),
-// &in2 = li_->getInterval(i2->second);
-// if (in.overlaps(in2)) {
-// std::cerr << in << " overlaps " << in2 << '\n';
-// assert(0);
-// }
-// }
-// }
};
}
void RA::releaseMemory()
{
- unhandled_.clear();
+ while (!unhandled_.empty()) unhandled_.pop();
fixed_.clear();
active_.clear();
inactive_.clear();
vrm_.reset(new VirtRegMap(*mf_));
if (!spiller_.get()) spiller_.reset(createSpiller());
- initIntervalSets(li_->getIntervals());
+ initIntervalSets();
linearScan();
DEBUG(std::cerr << "********** Function: "
<< mf_->getFunction()->getName() << '\n');
- DEBUG(printIntervals("unhandled", unhandled_.begin(), unhandled_.end()));
+ // DEBUG(printIntervals("unhandled", unhandled_.begin(), unhandled_.end()));
DEBUG(printIntervals("fixed", fixed_.begin(), fixed_.end()));
DEBUG(printIntervals("active", active_.begin(), active_.end()));
DEBUG(printIntervals("inactive", inactive_.begin(), inactive_.end()));
while (!unhandled_.empty()) {
// pick the interval with the earliest start point
- IntervalPtrs::value_type cur = unhandled_.front();
- unhandled_.pop_front();
+ LiveInterval* cur = unhandled_.top();
+ unhandled_.pop();
++numIterations;
DEBUG(std::cerr << "\n*** CURRENT ***: " << *cur << '\n');
DEBUG(printIntervals("active", active_.begin(), active_.end()));
DEBUG(printIntervals("inactive", inactive_.begin(), inactive_.end()));
- // DEBUG(verifyAssignment());
}
- numIntervals += li_->getIntervals().size();
+ numIntervals += li_->getNumIntervals();
efficiency = double(numIterations) / double(numIntervals);
// expire any remaining active intervals
- for (IntervalPtrs::iterator i = active_.begin(); i != active_.end(); ++i) {
+ for (IntervalPtrs::reverse_iterator
+ i = active_.rbegin(); i != active_.rend(); ) {
unsigned reg = (*i)->reg;
DEBUG(std::cerr << "\tinterval " << **i << " expired\n");
if (MRegisterInfo::isVirtualRegister(reg))
reg = vrm_->getPhys(reg);
prt_->delRegUse(reg);
+ i = IntervalPtrs::reverse_iterator(active_.erase(i.base()-1));
+ }
+
+ // expire any remaining inactive intervals
+ for (IntervalPtrs::reverse_iterator
+ i = inactive_.rbegin(); i != inactive_.rend(); ) {
+ DEBUG(std::cerr << "\tinterval " << **i << " expired\n");
+ i = IntervalPtrs::reverse_iterator(inactive_.erase(i.base()-1));
}
DEBUG(std::cerr << *vrm_);
}
-void RA::initIntervalSets(LiveIntervals::Intervals& li)
+void RA::initIntervalSets()
{
assert(unhandled_.empty() && fixed_.empty() &&
active_.empty() && inactive_.empty() &&
"interval sets should be empty on initialization");
- for (LiveIntervals::Intervals::iterator i = li.begin(), e = li.end();
- i != e; ++i) {
- unhandled_.push_back(&*i);
- if (MRegisterInfo::isPhysicalRegister(i->reg))
- fixed_.push_back(&*i);
+ for (LiveIntervals::iterator i = li_->begin(), e = li_->end(); i != e; ++i){
+ unhandled_.push(&i->second);
+ if (MRegisterInfo::isPhysicalRegister(i->second.reg))
+ fixed_.push_back(&i->second);
}
}
void RA::processActiveIntervals(IntervalPtrs::value_type cur)
{
DEBUG(std::cerr << "\tprocessing active intervals:\n");
- for (IntervalPtrs::iterator i = active_.begin(); i != active_.end();) {
+ for (IntervalPtrs::reverse_iterator
+ i = active_.rbegin(); i != active_.rend();) {
unsigned reg = (*i)->reg;
// remove expired intervals
if ((*i)->expiredAt(cur->start())) {
reg = vrm_->getPhys(reg);
prt_->delRegUse(reg);
// remove from active
- i = active_.erase(i);
+ i = IntervalPtrs::reverse_iterator(active_.erase(i.base()-1));
}
// move inactive intervals to inactive list
else if (!(*i)->liveAt(cur->start())) {
// add to inactive
inactive_.push_back(*i);
// remove from active
- i = active_.erase(i);
+ i = IntervalPtrs::reverse_iterator(active_.erase(i.base()-1));
}
else {
++i;
void RA::processInactiveIntervals(IntervalPtrs::value_type cur)
{
DEBUG(std::cerr << "\tprocessing inactive intervals:\n");
- for (IntervalPtrs::iterator i = inactive_.begin(); i != inactive_.end();) {
+ for (IntervalPtrs::reverse_iterator
+ i = inactive_.rbegin(); i != inactive_.rend();) {
unsigned reg = (*i)->reg;
// remove expired intervals
if ((*i)->expiredAt(cur->start())) {
DEBUG(std::cerr << "\t\tinterval " << **i << " expired\n");
// remove from inactive
- i = inactive_.erase(i);
+ i = IntervalPtrs::reverse_iterator(inactive_.erase(i.base()-1));
}
// move re-activated intervals in active list
else if ((*i)->liveAt(cur->start())) {
// add to active
active_.push_back(*i);
// remove from inactive
- i = inactive_.erase(i);
+ i = IntervalPtrs::reverse_iterator(inactive_.erase(i.base()-1));
}
else {
++i;
spillWeights_[*as] += weight;
}
-void RA::assignRegOrStackSlotAtInterval(IntervalPtrs::value_type cur)
+void RA::assignRegOrStackSlotAtInterval(LiveInterval* cur)
{
DEBUG(std::cerr << "\tallocating current interval: ");
int slot = vrm_->assignVirt2StackSlot(cur->reg);
std::vector<LiveInterval*> added =
li_->addIntervalsForSpills(*cur, *vrm_, slot);
-
- // merge added with unhandled
- std::vector<LiveInterval*>::iterator addedIt = added.begin();
- std::vector<LiveInterval*>::iterator addedItEnd = added.end();
- for (IntervalPtrs::iterator i = unhandled_.begin(), e = unhandled_.end();
- i != e && addedIt != addedItEnd; ++i) {
- if ((*i)->start() > (*addedIt)->start())
- i = unhandled_.insert(i, *(addedIt++));
- }
- while (addedIt != addedItEnd)
- unhandled_.push_back(*(addedIt++));
-
+ if (added.empty())
+ return; // Early exit if all spills were folded.
+
+ // Merge added with unhandled. Note that we know that
+ // addIntervalsForSpills returns intervals sorted by their starting
+ // point.
+ for (unsigned i = 0, e = added.size(); i != e; ++i)
+ unhandled_.push(added[i]);
return;
}
// push the current interval back to unhandled since we are going
// to re-run at least this iteration. Since we didn't modify it it
// should go back right in the front of the list
- unhandled_.push_front(cur);
+ unhandled_.push(cur);
// otherwise we spill all intervals aliasing the register with
// minimum weight, rollback to the interval with the earliest
assert(MRegisterInfo::isPhysicalRegister(minReg) &&
"did not choose a register to spill?");
std::vector<bool> toSpill(mri_->getNumRegs(), false);
+ // we are going to spill minReg and all its aliases
toSpill[minReg] = true;
for (const unsigned* as = mri_->getAliasSet(minReg); *as; ++as)
toSpill[*as] = true;
+
+ // the earliest start of a spilled interval indicates up to where
+ // in handled we need to roll back
unsigned earliestStart = cur->start();
+ // set of spilled vregs (used later to rollback properly)
std::set<unsigned> spilled;
- for (IntervalPtrs::iterator i = active_.begin(); i != active_.end(); ++i) {
+ // spill live intervals of virtual regs mapped to the physical
+ // register we want to clear (and its aliases). we only spill
+ // those that overlap with the current interval as the rest do not
+ // affect its allocation. we also keep track of the earliest start
+ // of all spilled live intervals since this will mark our rollback
+ // point
+ for (IntervalPtrs::iterator
+ i = active_.begin(); i != active_.end(); ++i) {
unsigned reg = (*i)->reg;
if (MRegisterInfo::isVirtualRegister(reg) &&
toSpill[vrm_->getPhys(reg)] &&
spilled.insert(reg);
}
}
- for (IntervalPtrs::iterator i = inactive_.begin();
- i != inactive_.end(); ++i) {
+ for (IntervalPtrs::iterator
+ i = inactive_.begin(); i != inactive_.end(); ++i) {
unsigned reg = (*i)->reg;
if (MRegisterInfo::isVirtualRegister(reg) &&
toSpill[vrm_->getPhys(reg)] &&
}
DEBUG(std::cerr << "\t\trolling back to: " << earliestStart << '\n');
- // scan handled in reverse order and undo each one, restoring the
- // state of unhandled
+ // scan handled in reverse order up to the earliaset start of a
+ // spilled live interval and undo each one, restoring the state of
+ // unhandled
while (!handled_.empty()) {
- IntervalPtrs::value_type i = handled_.back();
+ LiveInterval* i = handled_.back();
// if this interval starts before t we are done
if (i->start() < earliestStart)
break;
DEBUG(std::cerr << "\t\t\tundo changes for: " << *i << '\n');
handled_.pop_back();
+ // when undoing a live interval allocation we must know if it
+ // is active or inactive to properly update the PhysRegTracker
+ // and the VirtRegMap
IntervalPtrs::iterator it;
if ((it = find(active_.begin(), active_.end(), i)) != active_.end()) {
active_.erase(it);
if (MRegisterInfo::isPhysicalRegister(i->reg)) {
prt_->delRegUse(i->reg);
- unhandled_.push_front(i);
+ unhandled_.push(i);
}
else {
if (!spilled.count(i->reg))
- unhandled_.push_front(i);
+ unhandled_.push(i);
prt_->delRegUse(vrm_->getPhys(i->reg));
vrm_->clearVirt(i->reg);
}
else if ((it = find(inactive_.begin(), inactive_.end(), i)) != inactive_.end()) {
inactive_.erase(it);
if (MRegisterInfo::isPhysicalRegister(i->reg))
- unhandled_.push_front(i);
+ unhandled_.push(i);
else {
if (!spilled.count(i->reg))
- unhandled_.push_front(i);
+ unhandled_.push(i);
vrm_->clearVirt(i->reg);
}
}
else {
if (MRegisterInfo::isVirtualRegister(i->reg))
vrm_->clearVirt(i->reg);
- unhandled_.push_front(i);
+ unhandled_.push(i);
}
}
std::sort(added.begin(), added.end(), less_ptr<LiveInterval>());
// merge added with unhandled
- std::vector<LiveInterval*>::iterator addedIt = added.begin();
- std::vector<LiveInterval*>::iterator addedItEnd = added.end();
- for (IntervalPtrs::iterator i = unhandled_.begin(), e = unhandled_.end();
- i != e && addedIt != addedItEnd; ++i) {
- if ((*i)->start() > (*addedIt)->start())
- i = unhandled_.insert(i, *(addedIt++));
- }
- while (addedIt != addedItEnd)
- unhandled_.push_back(*(addedIt++));
-
+ for (unsigned i = 0, e = added.size(); i != e; ++i)
+ unhandled_.push(added[i]);
}
-unsigned RA::getFreePhysReg(IntervalPtrs::value_type cur)
+unsigned RA::getFreePhysReg(LiveInterval* cur)
{
const TargetRegisterClass* rc = mf_->getSSARegMap()->getRegClass(cur->reg);
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