#include "llvm/Target/MRegisterInfo.h"
#include "llvm/Target/TargetMachine.h"
#include "Support/Debug.h"
+#include "Support/Statistic.h"
+#include "Support/STLExtras.h"
#include "LiveIntervals.h"
#include "PhysRegTracker.h"
#include "VirtRegMap.h"
#include <algorithm>
+#include <cmath>
#include <iostream>
+#include <set>
using namespace llvm;
namespace {
+
+ Statistic<double> efficiency
+ ("regalloc", "Ratio of intervals processed over total intervals");
+
+ static unsigned numIterations = 0;
+ static unsigned numIntervals = 0;
+
class RA : public MachineFunctionPass {
private:
MachineFunction* mf_;
const TargetMachine* tm_;
const MRegisterInfo* mri_;
LiveIntervals* li_;
- typedef std::list<LiveIntervals::Interval*> IntervalPtrs;
+ typedef std::list<LiveInterval*> IntervalPtrs;
IntervalPtrs unhandled_, fixed_, active_, inactive_, handled_;
std::auto_ptr<PhysRegTracker> prt_;
std::auto_ptr<VirtRegMap> vrm_;
+ std::auto_ptr<Spiller> spiller_;
typedef std::vector<float> SpillWeights;
SpillWeights spillWeights_;
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 LiveIntervals::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();
+ fixed_.clear();
active_.clear();
inactive_.clear();
- fixed_.clear();
handled_.clear();
}
li_ = &getAnalysis<LiveIntervals>();
if (!prt_.get()) prt_.reset(new PhysRegTracker(*mri_));
vrm_.reset(new VirtRegMap(*mf_));
+ if (!spiller_.get()) spiller_.reset(createSpiller());
initIntervalSets(li_->getIntervals());
linearScan();
- eliminateVirtRegs(*mf_, *vrm_);
+ spiller_->runOnMachineFunction(*mf_, *vrm_);
return true;
}
DEBUG(printIntervals("active", active_.begin(), active_.end()));
DEBUG(printIntervals("inactive", inactive_.begin(), inactive_.end()));
- while (!unhandled_.empty() || !fixed_.empty()) {
+ while (!unhandled_.empty()) {
// pick the interval with the earliest start point
- IntervalPtrs::value_type cur;
- if (fixed_.empty()) {
- cur = unhandled_.front();
- unhandled_.pop_front();
- }
- else if (unhandled_.empty()) {
- cur = fixed_.front();
- fixed_.pop_front();
- }
- else if (unhandled_.front()->start() < fixed_.front()->start()) {
- cur = unhandled_.front();
- unhandled_.pop_front();
- }
- else {
- cur = fixed_.front();
- fixed_.pop_front();
- }
-
+ IntervalPtrs::value_type cur = unhandled_.front();
+ unhandled_.pop_front();
+ ++numIterations;
DEBUG(std::cerr << "\n*** CURRENT ***: " << *cur << '\n');
processActiveIntervals(cur);
DEBUG(printIntervals("inactive", inactive_.begin(), inactive_.end()));
// DEBUG(verifyAssignment());
}
+ numIntervals += li_->getIntervals().size();
+ efficiency = double(numIterations) / double(numIntervals);
// expire any remaining active intervals
for (IntervalPtrs::iterator i = active_.begin(); i != active_.end(); ++i) {
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);
- else
- unhandled_.push_back(&*i);
}
}
DEBUG(std::cerr << "\tassigning stack slot at interval "<< *cur << ":\n");
- float minWeight = std::numeric_limits<float>::infinity();
+ float minWeight = HUGE_VAL;
unsigned minReg = 0;
const TargetRegisterClass* rc = mf_->getSSARegMap()->getRegClass(cur->reg);
for (TargetRegisterClass::iterator i = rc->allocation_order_begin(*mf_);
DEBUG(std::cerr << "\t\tregister with min weight: "
<< mri_->getName(minReg) << " (" << minWeight << ")\n");
- // if the current has the minimum weight, we need to modify it,
- // push it back in unhandled and let the linear scan algorithm run
- // again
+ // if the current has the minimum weight, we need to spill it and
+ // add any added intervals back to unhandled, and restart
+ // linearscan.
if (cur->weight <= minWeight) {
DEBUG(std::cerr << "\t\t\tspilling(c): " << *cur << '\n';);
int slot = vrm_->assignVirt2StackSlot(cur->reg);
- li_->updateSpilledInterval(*cur, slot);
-
- // if we didn't eliminate the interval find where to add it
- // back to unhandled. We need to scan since unhandled are
- // sorted on earliest start point and we may have changed our
- // start point.
- if (!cur->empty()) {
- IntervalPtrs::iterator it = unhandled_.begin();
- while (it != unhandled_.end() && (*it)->start() < cur->start())
- ++it;
- unhandled_.insert(it, cur);
+ std::vector<LiveInterval*> added =
+ li_->addIntervalsForSpills(*cur, *vrm_, slot);
+ if (added.empty())
+ return; // Early exit if all spills were folded.
+#ifndef NDEBUG
+ int OldStart = -1;
+#endif
+
+ // Merge added with unhandled. Note that we know that
+ // addIntervalsForSpills returns intervals sorted by their starting
+ // point.
+ 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) {
+ while (addedIt != addedItEnd &&
+ (*i)->start() > (*addedIt)->start()) {
+#ifndef NDEBUG
+ // This code only works if addIntervalsForSpills retursn a
+ // sorted interval list. Assert this is the case now.
+ assert(OldStart <= (int)(*addedIt)->start() &&
+ "addIntervalsForSpills didn't return sorted interval list!");
+ OldStart = (*addedIt)->start();
+#endif
+ i = unhandled_.insert(i, *(addedIt++));
+ }
+ }
+
+ while (addedIt != addedItEnd) {
+#ifndef NDEBUG
+ // This code only works if addIntervalsForSpills retursn a
+ // sorted interval list. Assert this is the case now.
+ assert(OldStart <= (int)(*addedIt)->start() &&
+ "addIntervalsForSpills didn't return sorted interval list!");
+ OldStart = (*addedIt)->start();
+#endif
+ unhandled_.push_back(*(addedIt++));
}
return;
}
// otherwise we spill all intervals aliasing the register with
// minimum weight, rollback to the interval with the earliest
// start point and let the linear scan algorithm run again
+ std::vector<LiveInterval*> added;
assert(MRegisterInfo::isPhysicalRegister(minReg) &&
"did not choose a register to spill?");
std::vector<bool> toSpill(mri_->getNumRegs(), false);
toSpill[*as] = true;
unsigned earliestStart = cur->start();
+ std::set<unsigned> spilled;
+
for (IntervalPtrs::iterator i = active_.begin(); i != active_.end(); ++i) {
unsigned reg = (*i)->reg;
if (MRegisterInfo::isVirtualRegister(reg) &&
DEBUG(std::cerr << "\t\t\tspilling(a): " << **i << '\n');
earliestStart = std::min(earliestStart, (*i)->start());
int slot = vrm_->assignVirt2StackSlot((*i)->reg);
- li_->updateSpilledInterval(**i, slot);
+ std::vector<LiveInterval*> newIs =
+ li_->addIntervalsForSpills(**i, *vrm_, slot);
+ std::copy(newIs.begin(), newIs.end(), std::back_inserter(added));
+ spilled.insert(reg);
}
}
for (IntervalPtrs::iterator i = inactive_.begin();
DEBUG(std::cerr << "\t\t\tspilling(i): " << **i << '\n');
earliestStart = std::min(earliestStart, (*i)->start());
int slot = vrm_->assignVirt2StackSlot((*i)->reg);
- li_->updateSpilledInterval(**i, slot);
+ std::vector<LiveInterval*> newIs =
+ li_->addIntervalsForSpills(**i, *vrm_, slot);
+ std::copy(newIs.begin(), newIs.end(), std::back_inserter(added));
+ spilled.insert(reg);
}
}
DEBUG(std::cerr << "\t\trolling back to: " << earliestStart << '\n');
// scan handled in reverse order and undo each one, restoring the
- // state of unhandled and fixed
+ // state of unhandled
while (!handled_.empty()) {
IntervalPtrs::value_type i = handled_.back();
// if this interval starts before t we are done
- if (!i->empty() && i->start() < earliestStart)
+ if (i->start() < earliestStart)
break;
DEBUG(std::cerr << "\t\t\tundo changes for: " << *i << '\n');
handled_.pop_back();
if ((it = find(active_.begin(), active_.end(), i)) != active_.end()) {
active_.erase(it);
if (MRegisterInfo::isPhysicalRegister(i->reg)) {
- fixed_.push_front(i);
prt_->delRegUse(i->reg);
+ unhandled_.push_front(i);
}
else {
- prt_->delRegUse(vrm_->getPhys(i->reg));
- vrm_->clearVirtReg(i->reg);
- if (i->spilled()) {
- if (!i->empty()) {
- IntervalPtrs::iterator it = unhandled_.begin();
- while (it != unhandled_.end() &&
- (*it)->start() < i->start())
- ++it;
- unhandled_.insert(it, i);
- }
- }
- else
+ if (!spilled.count(i->reg))
unhandled_.push_front(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))
- fixed_.push_front(i);
+ unhandled_.push_front(i);
else {
- vrm_->clearVirtReg(i->reg);
- if (i->spilled()) {
- if (!i->empty()) {
- IntervalPtrs::iterator it = unhandled_.begin();
- while (it != unhandled_.end() &&
- (*it)->start() < i->start())
- ++it;
- unhandled_.insert(it, i);
- }
- }
- else
+ if (!spilled.count(i->reg))
unhandled_.push_front(i);
+ vrm_->clearVirt(i->reg);
}
}
else {
- if (MRegisterInfo::isPhysicalRegister(i->reg))
- fixed_.push_front(i);
- else {
- vrm_->clearVirtReg(i->reg);
- unhandled_.push_front(i);
- }
+ if (MRegisterInfo::isVirtualRegister(i->reg))
+ vrm_->clearVirt(i->reg);
+ unhandled_.push_front(i);
}
}
prt_->addRegUse(vrm_->getPhys((*i)->reg));
}
}
+
+ 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++));
+
}
unsigned RA::getFreePhysReg(IntervalPtrs::value_type cur)
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