//
// This file implements the LiveInterval analysis pass. Given some
// numbering of each the machine instructions (in this implemention
-// depth-first order) an interval [i, j] is said to be a live interval
+// depth-first order) an interval [i, j) is said to be a live interval
// for register v if there is no instruction with number j' > j such
// that v is live at j' abd there is no instruction with number i' < i
// such that v is live at i'. In this implementation intervals can
-// have holes, i.e. an interval might look like [1,20], [50,65],
-// [1000,1001]
+// have holes, i.e. an interval might look like [1,20), [50,65),
+// [1000,1001)
//
//===----------------------------------------------------------------------===//
#define LLVM_CODEGEN_LIVEINTERVALS_H
#include "llvm/CodeGen/MachineFunctionPass.h"
-#include "llvm/CodeGen/MachineBasicBlock.h"
-#include <iostream>
#include <list>
-#include <map>
-#include <vector>
namespace llvm {
public:
virtual void getAnalysisUsage(AnalysisUsage &AU) const;
+ virtual void releaseMemory();
- Intervals& getIntervals() { return intervals_; }
+ /// runOnMachineFunction - pass entry point
+ virtual bool runOnMachineFunction(MachineFunction&);
- MachineBasicBlockPtrs getOrderedMachineBasicBlockPtrs() const {
- MachineBasicBlockPtrs result;
- for (MbbIndex2MbbMap::const_iterator
- it = mbbi2mbbMap_.begin(), itEnd = mbbi2mbbMap_.end();
- it != itEnd; ++it) {
- result.push_back(it->second);
- }
- return result;
- }
+ Intervals& getIntervals() { return intervals_; }
const Reg2RegMap& getJoinedRegMap() const {
return r2rMap_;
unsigned rep(unsigned reg);
private:
- /// runOnMachineFunction - pass entry point
- bool runOnMachineFunction(MachineFunction&);
-
/// computeIntervals - compute live intervals
void computeIntervals();
//
// This file implements the LiveInterval analysis pass. Given some
// numbering of each the machine instructions (in this implemention
-// depth-first order) an interval [i, j] is said to be a live interval
+// depth-first order) an interval [i, j) is said to be a live interval
// for register v if there is no instruction with number j' > j such
// that v is live at j' abd there is no instruction with number i' < i
// such that v is live at i'. In this implementation intervals can
-// have holes, i.e. an interval might look like [1,20], [50,65],
-// [1000,1001]
+// have holes, i.e. an interval might look like [1,20), [50,65),
+// [1000,1001)
//
//===----------------------------------------------------------------------===//
#define LLVM_CODEGEN_LIVEINTERVALS_H
#include "llvm/CodeGen/MachineFunctionPass.h"
-#include "llvm/CodeGen/MachineBasicBlock.h"
-#include <iostream>
#include <list>
-#include <map>
-#include <vector>
namespace llvm {
public:
virtual void getAnalysisUsage(AnalysisUsage &AU) const;
+ virtual void releaseMemory();
- Intervals& getIntervals() { return intervals_; }
+ /// runOnMachineFunction - pass entry point
+ virtual bool runOnMachineFunction(MachineFunction&);
- MachineBasicBlockPtrs getOrderedMachineBasicBlockPtrs() const {
- MachineBasicBlockPtrs result;
- for (MbbIndex2MbbMap::const_iterator
- it = mbbi2mbbMap_.begin(), itEnd = mbbi2mbbMap_.end();
- it != itEnd; ++it) {
- result.push_back(it->second);
- }
- return result;
- }
+ Intervals& getIntervals() { return intervals_; }
const Reg2RegMap& getJoinedRegMap() const {
return r2rMap_;
unsigned rep(unsigned reg);
private:
- /// runOnMachineFunction - pass entry point
- bool runOnMachineFunction(MachineFunction&);
-
/// computeIntervals - compute live intervals
void computeIntervals();
#define DEBUG_TYPE "liveintervals"
#include "llvm/CodeGen/LiveIntervals.h"
-#include "llvm/Function.h"
#include "llvm/Analysis/LoopInfo.h"
#include "llvm/CodeGen/LiveVariables.h"
#include "llvm/CodeGen/MachineFrameInfo.h"
-#include "llvm/CodeGen/MachineFunctionPass.h"
#include "llvm/CodeGen/MachineInstr.h"
#include "llvm/CodeGen/Passes.h"
#include "llvm/CodeGen/SSARegMap.h"
#include "llvm/Target/MRegisterInfo.h"
#include "llvm/Target/TargetInstrInfo.h"
#include "llvm/Target/TargetMachine.h"
-#include "llvm/Target/TargetRegInfo.h"
#include "llvm/Support/CFG.h"
#include "Support/CommandLine.h"
#include "Support/Debug.h"
-#include "Support/DepthFirstIterator.h"
#include "Support/Statistic.h"
#include <cmath>
#include <iostream>
"Live Interval Analysis");
Statistic<> numIntervals("liveintervals", "Number of intervals");
+ Statistic<> numJoined ("liveintervals", "Number of intervals joined");
cl::opt<bool>
join("join-liveintervals",
MachineFunctionPass::getAnalysisUsage(AU);
}
+void LiveIntervals::releaseMemory()
+{
+ mbbi2mbbMap_.clear();
+ mi2iMap_.clear();
+ r2iMap_.clear();
+ r2iMap_.clear();
+ r2rMap_.clear();
+ intervals_.clear();
+}
+
+
/// runOnMachineFunction - Register allocate the whole function
///
bool LiveIntervals::runOnMachineFunction(MachineFunction &fn) {
tm_ = &fn.getTarget();
mri_ = tm_->getRegisterInfo();
lv_ = &getAnalysis<LiveVariables>();
- mbbi2mbbMap_.clear();
- mi2iMap_.clear();
- r2iMap_.clear();
- r2iMap_.clear();
- r2rMap_.clear();
- intervals_.clear();
// number MachineInstrs
unsigned miIndex = 0;
for (MachineFunction::iterator mbb = mf_->begin(), mbbEnd = mf_->end();
mbb != mbbEnd; ++mbb) {
const std::pair<MachineBasicBlock*, unsigned>& entry =
- lv_->getMachineBasicBlockInfo(&*mbb);
+ lv_->getMachineBasicBlockInfo(mbb);
bool inserted = mbbi2mbbMap_.insert(std::make_pair(entry.second,
entry.first)).second;
assert(inserted && "multiple index -> MachineBasicBlock");
const MachineBasicBlock* mbb = mbbi;
unsigned loopDepth = loopInfo.getLoopDepth(mbb->getBasicBlock());
- for (MachineBasicBlock::const_iterator mii = mbb->begin(),
- mie = mbb->end(); mii != mie; ++mii) {
- MachineInstr* mi = *mii;
+ if (loopDepth) {
+ for (MachineBasicBlock::const_iterator mii = mbb->begin(),
+ mie = mbb->end(); mii != mie; ++mii) {
+ MachineInstr* mi = *mii;
- for (int i = mi->getNumOperands() - 1; i >= 0; --i) {
- MachineOperand& mop = mi->getOperand(i);
+ for (int i = mi->getNumOperands() - 1; i >= 0; --i) {
+ MachineOperand& mop = mi->getOperand(i);
- if (!mop.isVirtualRegister())
- continue;
+ if (!mop.isVirtualRegister())
+ continue;
- unsigned reg = mop.getAllocatedRegNum();
- Reg2IntervalMap::iterator r2iit = r2iMap_.find(reg);
- assert(r2iit != r2iMap_.end());
- r2iit->second->weight += pow(10.0F, loopDepth);
+ unsigned reg = mop.getAllocatedRegNum();
+ Reg2IntervalMap::iterator r2iit = r2iMap_.find(reg);
+ assert(r2iit != r2iMap_.end());
+ r2iit->second->weight += pow(10.0F, loopDepth);
+ }
}
}
}
LiveVariables::VarInfo& vi = lv_->getVarInfo(reg);
Interval* interval = 0;
- Reg2IntervalMap::iterator r2iit = r2iMap_.find(reg);
- if (r2iit == r2iMap_.end()) {
+ Reg2IntervalMap::iterator r2iit = r2iMap_.lower_bound(reg);
+ if (r2iit == r2iMap_.end() || r2iit->first != reg) {
// add new interval
intervals_.push_back(Interval(reg));
// update interval index for this register
- bool inserted =
- r2iMap_.insert(std::make_pair(reg, --intervals_.end())).second;
- assert(inserted);
+ r2iMap_.insert(r2iit, std::make_pair(reg, --intervals_.end()));
interval = &intervals_.back();
}
else {
instrIndex :
getInstructionIndex(killerBlock->front()));
unsigned end = getInstructionIndex(killerInstr) + 1;
+ // we do not want to add invalid ranges. these can happen when
+ // a variable has its latest use and is redefined later on in
+ // the same basic block (common with variables introduced by
+ // PHI elimination)
if (start < end) {
killedInDefiningBasicBlock |= mbb == killerBlock;
interval->addRange(start, end);
exit:
assert(start < end && "did not find end of interval?");
- Reg2IntervalMap::iterator r2iit = r2iMap_.find(reg);
- if (r2iit != r2iMap_.end()) {
- Interval& interval = *r2iit->second;
- interval.addRange(start, end);
+ Reg2IntervalMap::iterator r2iit = r2iMap_.lower_bound(reg);
+ if (r2iit != r2iMap_.end() && r2iit->first == reg) {
+ r2iit->second->addRange(start, end);
}
else {
intervals_.push_back(Interval(reg));
- Interval& interval = intervals_.back();
// update interval index for this register
- bool inserted =
- r2iMap_.insert(std::make_pair(reg, --intervals_.end())).second;
- assert(inserted);
- interval.addRange(start, end);
+ r2iMap_.insert(r2iit, std::make_pair(reg, --intervals_.end()));
+ intervals_.back().addRange(start, end);
}
}
/// computeIntervals - computes the live intervals for virtual
/// registers. for some ordering of the machine instructions [1,N] a
-/// live interval is an interval [i, j] where 1 <= i <= j <= N for
+/// live interval is an interval [i, j) where 1 <= i <= j < N for
/// which a variable is live
void LiveIntervals::computeIntervals()
{
// handle explicit defs
for (int i = instr->getNumOperands() - 1; i >= 0; --i) {
MachineOperand& mop = instr->getOperand(i);
-
- if (!mop.isRegister())
- continue;
-
- // handle defs - build intervals
- if (mop.isDef())
+ // handle register defs - build intervals
+ if (mop.isRegister() && mop.isDef())
handleRegisterDef(mbb, mi, mop.getAllocatedRegNum());
}
}
intervals_.erase(dstInt);
}
}
+ ++numJoined;
}
}
}
DEBUG(for (Reg2RegMap::const_iterator i = r2rMap_.begin(),
e = r2rMap_.end(); i != e; ++i)
std::cerr << i->first << " -> " << i->second << '\n';);
-
+
}
bool LiveIntervals::overlapsAliases(const Interval& lhs,
}
+// This example is provided becaues liveAt() is non-obvious:
+//
+// this = [1,2), liveAt(1) will return false. The idea is that the
+// variable is defined in 1 and not live after definition. So it was
+// dead to begin with (defined but never used).
+//
+// this = [1,3), liveAt(2) will return false. The variable is used at
+// 2 but 2 is the last use so the variable's allocated register is
+// available for reuse.
bool LiveIntervals::Interval::liveAt(unsigned index) const
{
Range dummy(index, index+1);
return index >= r->first && index < (r->second - 1);
}
+// This example is provided because overlaps() is non-obvious:
+//
+// 0: A = ...
+// 1: B = ...
+// 2: C = A + B ;; last use of A
+//
+// The live intervals should look like:
+//
+// A = [0, 3)
+// B = [1, x)
+// C = [2, y)
+//
+// A->overlaps(C) should return false since we want to be able to join
+// A and C.
bool LiveIntervals::Interval::overlaps(const Interval& other) const
{
Ranges::const_iterator i = ranges.begin();
void LiveIntervals::Interval::addRange(unsigned start, unsigned end)
{
+ assert(start < end && "Invalid range to add!");
DEBUG(std::cerr << "\t\t\tadding range: [" << start <<','<< end << ") -> ");
//assert(start < end && "invalid range?");
Range range = std::make_pair(start, end);
LiveIntervals::Interval::Ranges::iterator
LiveIntervals::Interval::mergeRangesBackward(Ranges::iterator it)
{
- for (Ranges::iterator prev = it - 1;
- it != ranges.begin() && it->first <= prev->second; ) {
+ while (it != ranges.begin()) {
+ Ranges::iterator prev = it - 1;
+ if (it->first > prev->second) break;
+
it->first = std::min(it->first, prev->first);
it->second = std::max(it->second, prev->second);
it = ranges.erase(prev);
- prev = it - 1;
}
return it;
//
// This file implements the LiveInterval analysis pass. Given some
// numbering of each the machine instructions (in this implemention
-// depth-first order) an interval [i, j] is said to be a live interval
+// depth-first order) an interval [i, j) is said to be a live interval
// for register v if there is no instruction with number j' > j such
// that v is live at j' abd there is no instruction with number i' < i
// such that v is live at i'. In this implementation intervals can
-// have holes, i.e. an interval might look like [1,20], [50,65],
-// [1000,1001]
+// have holes, i.e. an interval might look like [1,20), [50,65),
+// [1000,1001)
//
//===----------------------------------------------------------------------===//
#define LLVM_CODEGEN_LIVEINTERVALS_H
#include "llvm/CodeGen/MachineFunctionPass.h"
-#include "llvm/CodeGen/MachineBasicBlock.h"
-#include <iostream>
#include <list>
-#include <map>
-#include <vector>
namespace llvm {
public:
virtual void getAnalysisUsage(AnalysisUsage &AU) const;
+ virtual void releaseMemory();
- Intervals& getIntervals() { return intervals_; }
+ /// runOnMachineFunction - pass entry point
+ virtual bool runOnMachineFunction(MachineFunction&);
- MachineBasicBlockPtrs getOrderedMachineBasicBlockPtrs() const {
- MachineBasicBlockPtrs result;
- for (MbbIndex2MbbMap::const_iterator
- it = mbbi2mbbMap_.begin(), itEnd = mbbi2mbbMap_.end();
- it != itEnd; ++it) {
- result.push_back(it->second);
- }
- return result;
- }
+ Intervals& getIntervals() { return intervals_; }
const Reg2RegMap& getJoinedRegMap() const {
return r2rMap_;
unsigned rep(unsigned reg);
private:
- /// runOnMachineFunction - pass entry point
- bool runOnMachineFunction(MachineFunction&);
-
/// computeIntervals - compute live intervals
void computeIntervals();
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