X-Git-Url: http://demsky.eecs.uci.edu/git/?a=blobdiff_plain;f=lib%2FCodeGen%2FRegAllocBasic.cpp;h=83dbbf2c1dbef70fef7f6a8e3ce9182e9b515ff6;hb=396618b43a85e12d290a90b181c6af5d7c0c5f11;hp=af7da53b89bae0dfd60f13c69471fa61064ce5a7;hpb=560ab9ebf78532df11188770c916c4eb6dcce1b2;p=oota-llvm.git diff --git a/lib/CodeGen/RegAllocBasic.cpp b/lib/CodeGen/RegAllocBasic.cpp index af7da53b89b..83dbbf2c1db 100644 --- a/lib/CodeGen/RegAllocBasic.cpp +++ b/lib/CodeGen/RegAllocBasic.cpp @@ -1,4 +1,4 @@ -//===-- RegAllocBasic.cpp - basic register allocator ----------------------===// +//===-- RegAllocBasic.cpp - Basic Register Allocator ----------------------===// // // The LLVM Compiler Infrastructure // @@ -13,20 +13,17 @@ //===----------------------------------------------------------------------===// #define DEBUG_TYPE "regalloc" -#include "LiveDebugVariables.h" -#include "LiveIntervalUnion.h" -#include "LiveRangeEdit.h" #include "RegAllocBase.h" +#include "LiveDebugVariables.h" #include "RenderMachineFunction.h" #include "Spiller.h" #include "VirtRegMap.h" -#include "llvm/ADT/OwningPtr.h" -#include "llvm/ADT/Statistic.h" #include "llvm/Analysis/AliasAnalysis.h" #include "llvm/Function.h" #include "llvm/PassAnalysisSupport.h" #include "llvm/CodeGen/CalcSpillWeights.h" #include "llvm/CodeGen/LiveIntervalAnalysis.h" +#include "llvm/CodeGen/LiveRangeEdit.h" #include "llvm/CodeGen/LiveStackAnalysis.h" #include "llvm/CodeGen/MachineFunctionPass.h" #include "llvm/CodeGen/MachineInstr.h" @@ -34,39 +31,20 @@ #include "llvm/CodeGen/MachineRegisterInfo.h" #include "llvm/CodeGen/Passes.h" #include "llvm/CodeGen/RegAllocRegistry.h" -#include "llvm/CodeGen/RegisterCoalescer.h" #include "llvm/Target/TargetMachine.h" #include "llvm/Target/TargetOptions.h" #include "llvm/Target/TargetRegisterInfo.h" -#ifndef NDEBUG -#include "llvm/ADT/SparseBitVector.h" -#endif #include "llvm/Support/Debug.h" -#include "llvm/Support/ErrorHandling.h" #include "llvm/Support/raw_ostream.h" -#include "llvm/Support/Timer.h" #include #include using namespace llvm; -STATISTIC(NumAssigned , "Number of registers assigned"); -STATISTIC(NumUnassigned , "Number of registers unassigned"); -STATISTIC(NumNewQueued , "Number of new live ranges queued"); - static RegisterRegAlloc basicRegAlloc("basic", "basic register allocator", createBasicRegisterAllocator); -// Temporary verification option until we can put verification inside -// MachineVerifier. -static cl::opt -VerifyRegAlloc("verify-regalloc", cl::location(RegAllocBase::VerifyEnabled), - cl::desc("Verify during register allocation")); - -const char *RegAllocBase::TimerGroupName = "Register Allocation"; -bool RegAllocBase::VerifyEnabled = false; - namespace { struct CompSpillWeight { bool operator()(LiveInterval *A, LiveInterval *B) const { @@ -85,7 +63,6 @@ class RABasic : public MachineFunctionPass, public RegAllocBase { // context MachineFunction *MF; - BitVector ReservedRegs; // analyses LiveStacks *LS; @@ -95,6 +72,11 @@ class RABasic : public MachineFunctionPass, public RegAllocBase std::auto_ptr SpillerInstance; std::priority_queue, CompSpillWeight> Queue; + + // Scratch space. Allocated here to avoid repeated malloc calls in + // selectOrSplit(). + BitVector UsableRegs; + public: RABasic(); @@ -130,6 +112,15 @@ public: /// Perform register allocation. virtual bool runOnMachineFunction(MachineFunction &mf); + // Helper for spilling all live virtual registers currently unified under preg + // that interfere with the most recently queried lvr. Return true if spilling + // was successful, and append any new spilled/split intervals to splitLVRs. + bool spillInterferences(LiveInterval &VirtReg, unsigned PhysReg, + SmallVectorImpl &SplitVRegs); + + void spillReg(LiveInterval &VirtReg, unsigned PhysReg, + SmallVectorImpl &SplitVRegs); + static char ID; }; @@ -141,8 +132,8 @@ RABasic::RABasic(): MachineFunctionPass(ID) { initializeLiveDebugVariablesPass(*PassRegistry::getPassRegistry()); initializeLiveIntervalsPass(*PassRegistry::getPassRegistry()); initializeSlotIndexesPass(*PassRegistry::getPassRegistry()); - initializeStrongPHIEliminationPass(*PassRegistry::getPassRegistry()); - initializeRegisterCoalescerAnalysisGroup(*PassRegistry::getPassRegistry()); + initializeRegisterCoalescerPass(*PassRegistry::getPassRegistry()); + initializeMachineSchedulerPass(*PassRegistry::getPassRegistry()); initializeCalculateSpillWeightsPass(*PassRegistry::getPassRegistry()); initializeLiveStacksPass(*PassRegistry::getPassRegistry()); initializeMachineDominatorTreePass(*PassRegistry::getPassRegistry()); @@ -159,9 +150,6 @@ void RABasic::getAnalysisUsage(AnalysisUsage &AU) const { AU.addPreserved(); AU.addRequired(); AU.addPreserved(); - if (StrongPHIElim) - AU.addRequiredID(StrongPHIEliminationID); - AU.addRequiredTransitive(); AU.addRequired(); AU.addRequired(); AU.addPreserved(); @@ -180,182 +168,10 @@ void RABasic::releaseMemory() { RegAllocBase::releaseMemory(); } -#ifndef NDEBUG -// Verify each LiveIntervalUnion. -void RegAllocBase::verify() { - LiveVirtRegBitSet VisitedVRegs; - OwningArrayPtr - unionVRegs(new LiveVirtRegBitSet[PhysReg2LiveUnion.numRegs()]); - - // Verify disjoint unions. - for (unsigned PhysReg = 0; PhysReg < PhysReg2LiveUnion.numRegs(); ++PhysReg) { - DEBUG(PhysReg2LiveUnion[PhysReg].print(dbgs(), TRI)); - LiveVirtRegBitSet &VRegs = unionVRegs[PhysReg]; - PhysReg2LiveUnion[PhysReg].verify(VRegs); - // Union + intersection test could be done efficiently in one pass, but - // don't add a method to SparseBitVector unless we really need it. - assert(!VisitedVRegs.intersects(VRegs) && "vreg in multiple unions"); - VisitedVRegs |= VRegs; - } - - // Verify vreg coverage. - for (LiveIntervals::iterator liItr = LIS->begin(), liEnd = LIS->end(); - liItr != liEnd; ++liItr) { - unsigned reg = liItr->first; - if (TargetRegisterInfo::isPhysicalRegister(reg)) continue; - if (!VRM->hasPhys(reg)) continue; // spilled? - unsigned PhysReg = VRM->getPhys(reg); - if (!unionVRegs[PhysReg].test(reg)) { - dbgs() << "LiveVirtReg " << reg << " not in union " << - TRI->getName(PhysReg) << "\n"; - llvm_unreachable("unallocated live vreg"); - } - } - // FIXME: I'm not sure how to verify spilled intervals. -} -#endif //!NDEBUG - -//===----------------------------------------------------------------------===// -// RegAllocBase Implementation -//===----------------------------------------------------------------------===// - -// Instantiate a LiveIntervalUnion for each physical register. -void RegAllocBase::LiveUnionArray::init(LiveIntervalUnion::Allocator &allocator, - unsigned NRegs) { - NumRegs = NRegs; - Array = - static_cast(malloc(sizeof(LiveIntervalUnion)*NRegs)); - for (unsigned r = 0; r != NRegs; ++r) - new(Array + r) LiveIntervalUnion(r, allocator); -} - -void RegAllocBase::init(VirtRegMap &vrm, LiveIntervals &lis) { - NamedRegionTimer T("Initialize", TimerGroupName, TimePassesIsEnabled); - TRI = &vrm.getTargetRegInfo(); - MRI = &vrm.getRegInfo(); - VRM = &vrm; - LIS = &lis; - const unsigned NumRegs = TRI->getNumRegs(); - if (NumRegs != PhysReg2LiveUnion.numRegs()) { - PhysReg2LiveUnion.init(UnionAllocator, NumRegs); - // Cache an interferece query for each physical reg - Queries.reset(new LiveIntervalUnion::Query[PhysReg2LiveUnion.numRegs()]); - } -} - -void RegAllocBase::LiveUnionArray::clear() { - if (!Array) - return; - for (unsigned r = 0; r != NumRegs; ++r) - Array[r].~LiveIntervalUnion(); - free(Array); - NumRegs = 0; - Array = 0; -} - -void RegAllocBase::releaseMemory() { - for (unsigned r = 0, e = PhysReg2LiveUnion.numRegs(); r != e; ++r) - PhysReg2LiveUnion[r].clear(); -} - -// Visit all the live registers. If they are already assigned to a physical -// register, unify them with the corresponding LiveIntervalUnion, otherwise push -// them on the priority queue for later assignment. -void RegAllocBase::seedLiveRegs() { - NamedRegionTimer T("Seed Live Regs", TimerGroupName, TimePassesIsEnabled); - for (LiveIntervals::iterator I = LIS->begin(), E = LIS->end(); I != E; ++I) { - unsigned RegNum = I->first; - LiveInterval &VirtReg = *I->second; - if (TargetRegisterInfo::isPhysicalRegister(RegNum)) - PhysReg2LiveUnion[RegNum].unify(VirtReg); - else - enqueue(&VirtReg); - } -} - -void RegAllocBase::assign(LiveInterval &VirtReg, unsigned PhysReg) { - DEBUG(dbgs() << "assigning " << PrintReg(VirtReg.reg, TRI) - << " to " << PrintReg(PhysReg, TRI) << '\n'); - assert(!VRM->hasPhys(VirtReg.reg) && "Duplicate VirtReg assignment"); - VRM->assignVirt2Phys(VirtReg.reg, PhysReg); - PhysReg2LiveUnion[PhysReg].unify(VirtReg); - ++NumAssigned; -} - -void RegAllocBase::unassign(LiveInterval &VirtReg, unsigned PhysReg) { - DEBUG(dbgs() << "unassigning " << PrintReg(VirtReg.reg, TRI) - << " from " << PrintReg(PhysReg, TRI) << '\n'); - assert(VRM->getPhys(VirtReg.reg) == PhysReg && "Inconsistent unassign"); - PhysReg2LiveUnion[PhysReg].extract(VirtReg); - VRM->clearVirt(VirtReg.reg); - ++NumUnassigned; -} - -// Top-level driver to manage the queue of unassigned VirtRegs and call the -// selectOrSplit implementation. -void RegAllocBase::allocatePhysRegs() { - seedLiveRegs(); - - // Continue assigning vregs one at a time to available physical registers. - while (LiveInterval *VirtReg = dequeue()) { - assert(!VRM->hasPhys(VirtReg->reg) && "Register already assigned"); - - // Unused registers can appear when the spiller coalesces snippets. - if (MRI->reg_nodbg_empty(VirtReg->reg)) { - DEBUG(dbgs() << "Dropping unused " << *VirtReg << '\n'); - LIS->removeInterval(VirtReg->reg); - continue; - } - - // Invalidate all interference queries, live ranges could have changed. - ++UserTag; - - // selectOrSplit requests the allocator to return an available physical - // register if possible and populate a list of new live intervals that - // result from splitting. - DEBUG(dbgs() << "\nselectOrSplit " - << MRI->getRegClass(VirtReg->reg)->getName() - << ':' << *VirtReg << '\n'); - typedef SmallVector VirtRegVec; - VirtRegVec SplitVRegs; - unsigned AvailablePhysReg = selectOrSplit(*VirtReg, SplitVRegs); - - if (AvailablePhysReg) - assign(*VirtReg, AvailablePhysReg); - - for (VirtRegVec::iterator I = SplitVRegs.begin(), E = SplitVRegs.end(); - I != E; ++I) { - LiveInterval *SplitVirtReg = *I; - assert(!VRM->hasPhys(SplitVirtReg->reg) && "Register already assigned"); - if (MRI->reg_nodbg_empty(SplitVirtReg->reg)) { - DEBUG(dbgs() << "not queueing unused " << *SplitVirtReg << '\n'); - LIS->removeInterval(SplitVirtReg->reg); - continue; - } - DEBUG(dbgs() << "queuing new interval: " << *SplitVirtReg << "\n"); - assert(TargetRegisterInfo::isVirtualRegister(SplitVirtReg->reg) && - "expect split value in virtual register"); - enqueue(SplitVirtReg); - ++NumNewQueued; - } - } -} - -// Check if this live virtual register interferes with a physical register. If -// not, then check for interference on each register that aliases with the -// physical register. Return the interfering register. -unsigned RegAllocBase::checkPhysRegInterference(LiveInterval &VirtReg, - unsigned PhysReg) { - for (const unsigned *AliasI = TRI->getOverlaps(PhysReg); *AliasI; ++AliasI) - if (query(VirtReg, *AliasI).checkInterference()) - return *AliasI; - return 0; -} - -// Helper for spillInteferences() that spills all interfering vregs currently +// Helper for spillInterferences() that spills all interfering vregs currently // assigned to this physical register. -void RegAllocBase::spillReg(LiveInterval& VirtReg, unsigned PhysReg, - SmallVectorImpl &SplitVRegs) { +void RABasic::spillReg(LiveInterval& VirtReg, unsigned PhysReg, + SmallVectorImpl &SplitVRegs) { LiveIntervalUnion::Query &Q = query(VirtReg, PhysReg); assert(Q.seenAllInterferences() && "need collectInterferences()"); const SmallVectorImpl &PendingSpills = Q.interferingVRegs(); @@ -371,7 +187,7 @@ void RegAllocBase::spillReg(LiveInterval& VirtReg, unsigned PhysReg, unassign(SpilledVReg, PhysReg); // Spill the extracted interval. - LiveRangeEdit LRE(SpilledVReg, SplitVRegs, 0, &PendingSpills); + LiveRangeEdit LRE(&SpilledVReg, SplitVRegs, *MF, *LIS, VRM); spiller().spill(LRE); } // After extracting segments, the query's results are invalid. But keep the @@ -382,15 +198,14 @@ void RegAllocBase::spillReg(LiveInterval& VirtReg, unsigned PhysReg, // Spill or split all live virtual registers currently unified under PhysReg // that interfere with VirtReg. The newly spilled or split live intervals are // returned by appending them to SplitVRegs. -bool -RegAllocBase::spillInterferences(LiveInterval &VirtReg, unsigned PhysReg, +bool RABasic::spillInterferences(LiveInterval &VirtReg, unsigned PhysReg, SmallVectorImpl &SplitVRegs) { // Record each interference and determine if all are spillable before mutating // either the union or live intervals. unsigned NumInterferences = 0; // Collect interferences assigned to any alias of the physical register. - for (const unsigned *asI = TRI->getOverlaps(PhysReg); *asI; ++asI) { - LiveIntervalUnion::Query &QAlias = query(VirtReg, *asI); + for (MCRegAliasIterator AI(PhysReg, TRI, true); AI.isValid(); ++AI) { + LiveIntervalUnion::Query &QAlias = query(VirtReg, *AI); NumInterferences += QAlias.collectInterferingVRegs(); if (QAlias.seenUnspillableVReg()) { return false; @@ -401,48 +216,11 @@ RegAllocBase::spillInterferences(LiveInterval &VirtReg, unsigned PhysReg, assert(NumInterferences > 0 && "expect interference"); // Spill each interfering vreg allocated to PhysReg or an alias. - for (const unsigned *AliasI = TRI->getOverlaps(PhysReg); *AliasI; ++AliasI) - spillReg(VirtReg, *AliasI, SplitVRegs); + for (MCRegAliasIterator AI(PhysReg, TRI, true); AI.isValid(); ++AI) + spillReg(VirtReg, *AI, SplitVRegs); return true; } -// Add newly allocated physical registers to the MBB live in sets. -void RegAllocBase::addMBBLiveIns(MachineFunction *MF) { - NamedRegionTimer T("MBB Live Ins", TimerGroupName, TimePassesIsEnabled); - SlotIndexes *Indexes = LIS->getSlotIndexes(); - if (MF->size() <= 1) - return; - - LiveIntervalUnion::SegmentIter SI; - for (unsigned PhysReg = 0; PhysReg < PhysReg2LiveUnion.numRegs(); ++PhysReg) { - LiveIntervalUnion &LiveUnion = PhysReg2LiveUnion[PhysReg]; - if (LiveUnion.empty()) - continue; - MachineFunction::iterator MBB = llvm::next(MF->begin()); - MachineFunction::iterator MFE = MF->end(); - SlotIndex Start, Stop; - tie(Start, Stop) = Indexes->getMBBRange(MBB); - SI.setMap(LiveUnion.getMap()); - SI.find(Start); - while (SI.valid()) { - if (SI.start() <= Start) { - if (!MBB->isLiveIn(PhysReg)) - MBB->addLiveIn(PhysReg); - } else if (SI.start() > Stop) - MBB = Indexes->getMBBFromIndex(SI.start()); - if (++MBB == MFE) - break; - tie(Start, Stop) = Indexes->getMBBRange(MBB); - SI.advanceTo(Start); - } - } -} - - -//===----------------------------------------------------------------------===// -// RABasic Implementation -//===----------------------------------------------------------------------===// - // Driver for the register assignment and splitting heuristics. // Manages iteration over the LiveIntervalUnions. // @@ -457,18 +235,24 @@ void RegAllocBase::addMBBLiveIns(MachineFunction *MF) { // selectOrSplit(). unsigned RABasic::selectOrSplit(LiveInterval &VirtReg, SmallVectorImpl &SplitVRegs) { + // Check for register mask interference. When live ranges cross calls, the + // set of usable registers is reduced to the callee-saved ones. + bool CrossRegMasks = LIS->checkRegMaskInterference(VirtReg, UsableRegs); + // Populate a list of physical register spill candidates. SmallVector PhysRegSpillCands; // Check for an available register in this class. - const TargetRegisterClass *TRC = MRI->getRegClass(VirtReg.reg); - - for (TargetRegisterClass::iterator I = TRC->allocation_order_begin(*MF), - E = TRC->allocation_order_end(*MF); - I != E; ++I) { - + ArrayRef Order = + RegClassInfo.getOrder(MRI->getRegClass(VirtReg.reg)); + for (ArrayRef::iterator I = Order.begin(), E = Order.end(); I != E; + ++I) { unsigned PhysReg = *I; - if (ReservedRegs.test(PhysReg)) continue; + + // If PhysReg is clobbered by a register mask, it isn't useful for + // allocation or spilling. + if (CrossRegMasks && !UsableRegs.test(PhysReg)) + continue; // Check interference and as a side effect, intialize queries for this // VirtReg and its aliases. @@ -477,8 +261,9 @@ unsigned RABasic::selectOrSplit(LiveInterval &VirtReg, // Found an available register. return PhysReg; } - LiveInterval *interferingVirtReg = - Queries[interfReg].firstInterference().liveUnionPos().value(); + LiveIntervalUnion::Query &IntfQ = query(VirtReg, interfReg); + IntfQ.collectInterferingVRegs(1); + LiveInterval *interferingVirtReg = IntfQ.interferingVRegs().front(); // The current VirtReg must either be spillable, or one of its interferences // must have less spill weight. @@ -497,9 +282,12 @@ unsigned RABasic::selectOrSplit(LiveInterval &VirtReg, // Tell the caller to allocate to this newly freed physical register. return *PhysRegI; } + // No other spill candidates were found, so spill the current VirtReg. DEBUG(dbgs() << "spilling: " << VirtReg << '\n'); - LiveRangeEdit LRE(VirtReg, SplitVRegs); + if (!VirtReg.isSpillable()) + return ~0u; + LiveRangeEdit LRE(&VirtReg, SplitVRegs, *MF, *LIS, VRM); spiller().spill(LRE); // The live virtual register requesting allocation was spilled, so tell @@ -516,9 +304,6 @@ bool RABasic::runOnMachineFunction(MachineFunction &mf) { DEBUG(RMF = &getAnalysis()); RegAllocBase::init(getAnalysis(), getAnalysis()); - - ReservedRegs = TRI->getReservedRegs(*MF); - SpillerInstance.reset(createInlineSpiller(*this, *MF, *VRM)); allocatePhysRegs(); @@ -557,7 +342,10 @@ bool RABasic::runOnMachineFunction(MachineFunction &mf) { // Write out new DBG_VALUE instructions. getAnalysis().emitDebugValues(VRM); - // The pass output is in VirtRegMap. Release all the transient data. + // All machine operands and other references to virtual registers have been + // replaced. Remove the virtual registers and release all the transient data. + VRM->clearAllVirt(); + MRI->clearVirtRegs(); releaseMemory(); return true;