llvm-6502/lib/CodeGen/LiveRegMatrix.cpp
Eric Christopher 6035518e3b Have MachineFunction cache a pointer to the subtarget to make lookups
shorter/easier and have the DAG use that to do the same lookup. This
can be used in the future for TargetMachine based caching lookups from
the MachineFunction easily.

Update the MIPS subtarget switching machinery to update this pointer
at the same time it runs.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@214838 91177308-0d34-0410-b5e6-96231b3b80d8
2014-08-05 02:39:49 +00:00

160 lines
5.5 KiB
C++

//===-- LiveRegMatrix.cpp - Track register interference -------------------===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file defines the LiveRegMatrix analysis pass.
//
//===----------------------------------------------------------------------===//
#include "llvm/CodeGen/LiveRegMatrix.h"
#include "RegisterCoalescer.h"
#include "llvm/ADT/Statistic.h"
#include "llvm/CodeGen/LiveIntervalAnalysis.h"
#include "llvm/CodeGen/MachineRegisterInfo.h"
#include "llvm/CodeGen/VirtRegMap.h"
#include "llvm/Support/Debug.h"
#include "llvm/Support/raw_ostream.h"
#include "llvm/Target/TargetMachine.h"
#include "llvm/Target/TargetRegisterInfo.h"
using namespace llvm;
#define DEBUG_TYPE "regalloc"
STATISTIC(NumAssigned , "Number of registers assigned");
STATISTIC(NumUnassigned , "Number of registers unassigned");
char LiveRegMatrix::ID = 0;
INITIALIZE_PASS_BEGIN(LiveRegMatrix, "liveregmatrix",
"Live Register Matrix", false, false)
INITIALIZE_PASS_DEPENDENCY(LiveIntervals)
INITIALIZE_PASS_DEPENDENCY(VirtRegMap)
INITIALIZE_PASS_END(LiveRegMatrix, "liveregmatrix",
"Live Register Matrix", false, false)
LiveRegMatrix::LiveRegMatrix() : MachineFunctionPass(ID),
UserTag(0), RegMaskTag(0), RegMaskVirtReg(0) {}
void LiveRegMatrix::getAnalysisUsage(AnalysisUsage &AU) const {
AU.setPreservesAll();
AU.addRequiredTransitive<LiveIntervals>();
AU.addRequiredTransitive<VirtRegMap>();
MachineFunctionPass::getAnalysisUsage(AU);
}
bool LiveRegMatrix::runOnMachineFunction(MachineFunction &MF) {
TRI = MF.getSubtarget().getRegisterInfo();
MRI = &MF.getRegInfo();
LIS = &getAnalysis<LiveIntervals>();
VRM = &getAnalysis<VirtRegMap>();
unsigned NumRegUnits = TRI->getNumRegUnits();
if (NumRegUnits != Matrix.size())
Queries.reset(new LiveIntervalUnion::Query[NumRegUnits]);
Matrix.init(LIUAlloc, NumRegUnits);
// Make sure no stale queries get reused.
invalidateVirtRegs();
return false;
}
void LiveRegMatrix::releaseMemory() {
for (unsigned i = 0, e = Matrix.size(); i != e; ++i) {
Matrix[i].clear();
// No need to clear Queries here, since LiveIntervalUnion::Query doesn't
// have anything important to clear and LiveRegMatrix's runOnFunction()
// does a std::unique_ptr::reset anyways.
}
}
void LiveRegMatrix::assign(LiveInterval &VirtReg, unsigned PhysReg) {
DEBUG(dbgs() << "assigning " << PrintReg(VirtReg.reg, TRI)
<< " to " << PrintReg(PhysReg, TRI) << ':');
assert(!VRM->hasPhys(VirtReg.reg) && "Duplicate VirtReg assignment");
VRM->assignVirt2Phys(VirtReg.reg, PhysReg);
MRI->setPhysRegUsed(PhysReg);
for (MCRegUnitIterator Units(PhysReg, TRI); Units.isValid(); ++Units) {
DEBUG(dbgs() << ' ' << PrintRegUnit(*Units, TRI));
Matrix[*Units].unify(VirtReg);
}
++NumAssigned;
DEBUG(dbgs() << '\n');
}
void LiveRegMatrix::unassign(LiveInterval &VirtReg) {
unsigned PhysReg = VRM->getPhys(VirtReg.reg);
DEBUG(dbgs() << "unassigning " << PrintReg(VirtReg.reg, TRI)
<< " from " << PrintReg(PhysReg, TRI) << ':');
VRM->clearVirt(VirtReg.reg);
for (MCRegUnitIterator Units(PhysReg, TRI); Units.isValid(); ++Units) {
DEBUG(dbgs() << ' ' << PrintRegUnit(*Units, TRI));
Matrix[*Units].extract(VirtReg);
}
++NumUnassigned;
DEBUG(dbgs() << '\n');
}
bool LiveRegMatrix::checkRegMaskInterference(LiveInterval &VirtReg,
unsigned PhysReg) {
// Check if the cached information is valid.
// The same BitVector can be reused for all PhysRegs.
// We could cache multiple VirtRegs if it becomes necessary.
if (RegMaskVirtReg != VirtReg.reg || RegMaskTag != UserTag) {
RegMaskVirtReg = VirtReg.reg;
RegMaskTag = UserTag;
RegMaskUsable.clear();
LIS->checkRegMaskInterference(VirtReg, RegMaskUsable);
}
// The BitVector is indexed by PhysReg, not register unit.
// Regmask interference is more fine grained than regunits.
// For example, a Win64 call can clobber %ymm8 yet preserve %xmm8.
return !RegMaskUsable.empty() && (!PhysReg || !RegMaskUsable.test(PhysReg));
}
bool LiveRegMatrix::checkRegUnitInterference(LiveInterval &VirtReg,
unsigned PhysReg) {
if (VirtReg.empty())
return false;
CoalescerPair CP(VirtReg.reg, PhysReg, *TRI);
for (MCRegUnitIterator Units(PhysReg, TRI); Units.isValid(); ++Units) {
const LiveRange &UnitRange = LIS->getRegUnit(*Units);
if (VirtReg.overlaps(UnitRange, CP, *LIS->getSlotIndexes()))
return true;
}
return false;
}
LiveIntervalUnion::Query &LiveRegMatrix::query(LiveInterval &VirtReg,
unsigned RegUnit) {
LiveIntervalUnion::Query &Q = Queries[RegUnit];
Q.init(UserTag, &VirtReg, &Matrix[RegUnit]);
return Q;
}
LiveRegMatrix::InterferenceKind
LiveRegMatrix::checkInterference(LiveInterval &VirtReg, unsigned PhysReg) {
if (VirtReg.empty())
return IK_Free;
// Regmask interference is the fastest check.
if (checkRegMaskInterference(VirtReg, PhysReg))
return IK_RegMask;
// Check for fixed interference.
if (checkRegUnitInterference(VirtReg, PhysReg))
return IK_RegUnit;
// Check the matrix for virtual register interference.
for (MCRegUnitIterator Units(PhysReg, TRI); Units.isValid(); ++Units)
if (query(VirtReg, *Units).checkInterference())
return IK_VirtReg;
return IK_Free;
}