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https://github.com/c64scene-ar/llvm-6502.git
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f15735e039
large register files. The omission of Queries.clear() is perfectly safe because LiveIntervalUnion::Query doesn't contain any data that needs freeing and because LiveRegMatrix::runOnFunction happens to reset the OwningArrayPtr holding Queries every time it is run, so there's no need to zero out the queries either. Not having to do this for very large numbers of physregs is a noticeable constant cost reduction in compilation of small programs. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@200913 91177308-0d34-0410-b5e6-96231b3b80d8
159 lines
5.5 KiB
C++
159 lines
5.5 KiB
C++
//===-- LiveRegMatrix.cpp - Track register interference -------------------===//
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//
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// The LLVM Compiler Infrastructure
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//
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// This file is distributed under the University of Illinois Open Source
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// License. See LICENSE.TXT for details.
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//
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//===----------------------------------------------------------------------===//
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//
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// This file defines the LiveRegMatrix analysis pass.
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//
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//===----------------------------------------------------------------------===//
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#define DEBUG_TYPE "regalloc"
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#include "llvm/CodeGen/LiveRegMatrix.h"
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#include "RegisterCoalescer.h"
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#include "llvm/ADT/Statistic.h"
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#include "llvm/CodeGen/LiveIntervalAnalysis.h"
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#include "llvm/CodeGen/MachineRegisterInfo.h"
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#include "llvm/CodeGen/VirtRegMap.h"
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#include "llvm/Support/Debug.h"
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#include "llvm/Support/raw_ostream.h"
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#include "llvm/Target/TargetMachine.h"
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#include "llvm/Target/TargetRegisterInfo.h"
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using namespace llvm;
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STATISTIC(NumAssigned , "Number of registers assigned");
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STATISTIC(NumUnassigned , "Number of registers unassigned");
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char LiveRegMatrix::ID = 0;
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INITIALIZE_PASS_BEGIN(LiveRegMatrix, "liveregmatrix",
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"Live Register Matrix", false, false)
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INITIALIZE_PASS_DEPENDENCY(LiveIntervals)
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INITIALIZE_PASS_DEPENDENCY(VirtRegMap)
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INITIALIZE_PASS_END(LiveRegMatrix, "liveregmatrix",
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"Live Register Matrix", false, false)
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LiveRegMatrix::LiveRegMatrix() : MachineFunctionPass(ID),
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UserTag(0), RegMaskTag(0), RegMaskVirtReg(0) {}
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void LiveRegMatrix::getAnalysisUsage(AnalysisUsage &AU) const {
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AU.setPreservesAll();
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AU.addRequiredTransitive<LiveIntervals>();
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AU.addRequiredTransitive<VirtRegMap>();
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MachineFunctionPass::getAnalysisUsage(AU);
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}
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bool LiveRegMatrix::runOnMachineFunction(MachineFunction &MF) {
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TRI = MF.getTarget().getRegisterInfo();
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MRI = &MF.getRegInfo();
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LIS = &getAnalysis<LiveIntervals>();
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VRM = &getAnalysis<VirtRegMap>();
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unsigned NumRegUnits = TRI->getNumRegUnits();
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if (NumRegUnits != Matrix.size())
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Queries.reset(new LiveIntervalUnion::Query[NumRegUnits]);
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Matrix.init(LIUAlloc, NumRegUnits);
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// Make sure no stale queries get reused.
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invalidateVirtRegs();
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return false;
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}
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void LiveRegMatrix::releaseMemory() {
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for (unsigned i = 0, e = Matrix.size(); i != e; ++i) {
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Matrix[i].clear();
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// No need to clear Queries here, since LiveIntervalUnion::Query doesn't
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// have anything important to clear and LiveRegMatrix's runOnFunction()
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// does a OwningPtr::reset anyways.
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}
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}
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void LiveRegMatrix::assign(LiveInterval &VirtReg, unsigned PhysReg) {
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DEBUG(dbgs() << "assigning " << PrintReg(VirtReg.reg, TRI)
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<< " to " << PrintReg(PhysReg, TRI) << ':');
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assert(!VRM->hasPhys(VirtReg.reg) && "Duplicate VirtReg assignment");
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VRM->assignVirt2Phys(VirtReg.reg, PhysReg);
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MRI->setPhysRegUsed(PhysReg);
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for (MCRegUnitIterator Units(PhysReg, TRI); Units.isValid(); ++Units) {
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DEBUG(dbgs() << ' ' << PrintRegUnit(*Units, TRI));
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Matrix[*Units].unify(VirtReg);
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}
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++NumAssigned;
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DEBUG(dbgs() << '\n');
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}
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void LiveRegMatrix::unassign(LiveInterval &VirtReg) {
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unsigned PhysReg = VRM->getPhys(VirtReg.reg);
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DEBUG(dbgs() << "unassigning " << PrintReg(VirtReg.reg, TRI)
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<< " from " << PrintReg(PhysReg, TRI) << ':');
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VRM->clearVirt(VirtReg.reg);
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for (MCRegUnitIterator Units(PhysReg, TRI); Units.isValid(); ++Units) {
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DEBUG(dbgs() << ' ' << PrintRegUnit(*Units, TRI));
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Matrix[*Units].extract(VirtReg);
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}
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++NumUnassigned;
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DEBUG(dbgs() << '\n');
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}
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bool LiveRegMatrix::checkRegMaskInterference(LiveInterval &VirtReg,
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unsigned PhysReg) {
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// Check if the cached information is valid.
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// The same BitVector can be reused for all PhysRegs.
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// We could cache multiple VirtRegs if it becomes necessary.
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if (RegMaskVirtReg != VirtReg.reg || RegMaskTag != UserTag) {
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RegMaskVirtReg = VirtReg.reg;
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RegMaskTag = UserTag;
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RegMaskUsable.clear();
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LIS->checkRegMaskInterference(VirtReg, RegMaskUsable);
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}
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// The BitVector is indexed by PhysReg, not register unit.
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// Regmask interference is more fine grained than regunits.
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// For example, a Win64 call can clobber %ymm8 yet preserve %xmm8.
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return !RegMaskUsable.empty() && (!PhysReg || !RegMaskUsable.test(PhysReg));
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}
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bool LiveRegMatrix::checkRegUnitInterference(LiveInterval &VirtReg,
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unsigned PhysReg) {
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if (VirtReg.empty())
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return false;
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CoalescerPair CP(VirtReg.reg, PhysReg, *TRI);
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for (MCRegUnitIterator Units(PhysReg, TRI); Units.isValid(); ++Units) {
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const LiveRange &UnitRange = LIS->getRegUnit(*Units);
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if (VirtReg.overlaps(UnitRange, CP, *LIS->getSlotIndexes()))
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return true;
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}
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return false;
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}
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LiveIntervalUnion::Query &LiveRegMatrix::query(LiveInterval &VirtReg,
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unsigned RegUnit) {
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LiveIntervalUnion::Query &Q = Queries[RegUnit];
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Q.init(UserTag, &VirtReg, &Matrix[RegUnit]);
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return Q;
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}
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LiveRegMatrix::InterferenceKind
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LiveRegMatrix::checkInterference(LiveInterval &VirtReg, unsigned PhysReg) {
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if (VirtReg.empty())
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return IK_Free;
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// Regmask interference is the fastest check.
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if (checkRegMaskInterference(VirtReg, PhysReg))
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return IK_RegMask;
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// Check for fixed interference.
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if (checkRegUnitInterference(VirtReg, PhysReg))
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return IK_RegUnit;
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// Check the matrix for virtual register interference.
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for (MCRegUnitIterator Units(PhysReg, TRI); Units.isValid(); ++Units)
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if (query(VirtReg, *Units).checkInterference())
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return IK_VirtReg;
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return IK_Free;
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}
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