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https://github.com/c64scene-ar/llvm-6502.git
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git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@58309 91177308-0d34-0410-b5e6-96231b3b80d8
730 lines
26 KiB
C++
730 lines
26 KiB
C++
//===-- PreAllocSplitting.cpp - Pre-allocation Interval Spltting Pass. ----===//
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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 implements the machine instruction level pre-register allocation
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// live interval splitting pass. It finds live interval barriers, i.e.
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// instructions which will kill all physical registers in certain register
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// classes, and split all live intervals which cross the barrier.
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//
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//===----------------------------------------------------------------------===//
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#define DEBUG_TYPE "pre-alloc-split"
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#include "llvm/CodeGen/LiveIntervalAnalysis.h"
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#include "llvm/CodeGen/MachineFrameInfo.h"
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#include "llvm/CodeGen/MachineFunctionPass.h"
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#include "llvm/CodeGen/MachineLoopInfo.h"
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#include "llvm/CodeGen/MachineRegisterInfo.h"
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#include "llvm/CodeGen/Passes.h"
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#include "llvm/CodeGen/RegisterCoalescer.h"
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#include "llvm/Target/TargetInstrInfo.h"
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#include "llvm/Target/TargetMachine.h"
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#include "llvm/Target/TargetOptions.h"
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#include "llvm/Target/TargetRegisterInfo.h"
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#include "llvm/Support/CommandLine.h"
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#include "llvm/Support/Debug.h"
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#include "llvm/ADT/SmallPtrSet.h"
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#include "llvm/ADT/Statistic.h"
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#include <map>
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using namespace llvm;
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STATISTIC(NumSplit , "Number of intervals split");
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namespace {
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class VISIBILITY_HIDDEN PreAllocSplitting : public MachineFunctionPass {
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MachineFunction *CurMF;
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const TargetMachine *TM;
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const TargetInstrInfo *TII;
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MachineFrameInfo *MFI;
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MachineRegisterInfo *MRI;
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LiveIntervals *LIs;
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// Barrier - Current barrier being processed.
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MachineInstr *Barrier;
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// BarrierMBB - Basic block where the barrier resides in.
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MachineBasicBlock *BarrierMBB;
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// Barrier - Current barrier index.
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unsigned BarrierIdx;
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// CurrLI - Current live interval being split.
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LiveInterval *CurrLI;
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// LIValNoSSMap - A map from live interval and val# pairs to spill slots.
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// This records what live interval's val# has been split and what spill
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// slot was used.
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std::map<std::pair<unsigned, unsigned>, int> LIValNoSSMap;
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// RestoreMIs - All the restores inserted due to live interval splitting.
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SmallPtrSet<MachineInstr*, 8> RestoreMIs;
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public:
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static char ID;
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PreAllocSplitting() : MachineFunctionPass(&ID) {}
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virtual bool runOnMachineFunction(MachineFunction &MF);
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virtual void getAnalysisUsage(AnalysisUsage &AU) const {
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AU.addRequired<LiveIntervals>();
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AU.addPreserved<LiveIntervals>();
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AU.addPreserved<RegisterCoalescer>();
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if (StrongPHIElim)
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AU.addPreservedID(StrongPHIEliminationID);
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else
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AU.addPreservedID(PHIEliminationID);
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MachineFunctionPass::getAnalysisUsage(AU);
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}
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virtual void releaseMemory() {
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LIValNoSSMap.clear();
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RestoreMIs.clear();
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}
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virtual const char *getPassName() const {
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return "Pre-Register Allocaton Live Interval Splitting";
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}
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/// print - Implement the dump method.
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virtual void print(std::ostream &O, const Module* M = 0) const {
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LIs->print(O, M);
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}
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void print(std::ostream *O, const Module* M = 0) const {
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if (O) print(*O, M);
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}
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private:
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MachineBasicBlock::iterator
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findNextEmptySlot(MachineBasicBlock*, MachineInstr*,
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unsigned&);
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MachineBasicBlock::iterator
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findSpillPoint(MachineBasicBlock*, MachineInstr*,
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SmallPtrSet<MachineInstr*, 4>&, unsigned&);
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MachineBasicBlock::iterator
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findRestorePoint(MachineBasicBlock*, MachineInstr*, unsigned,
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SmallPtrSet<MachineInstr*, 4>&, unsigned&);
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void RecordSplit(unsigned, unsigned, unsigned, int);
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bool isAlreadySplit(unsigned, unsigned, int&);
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void UpdateIntervalForSplit(VNInfo*, unsigned, unsigned);
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bool ShrinkWrapToLastUse(MachineBasicBlock*,
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SmallVector<MachineOperand*, 4>&,
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SmallPtrSet<MachineInstr*, 4>&);
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void ShrinkWrapLiveInterval(VNInfo*, MachineBasicBlock*, MachineBasicBlock*,
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MachineBasicBlock*, SmallPtrSet<MachineBasicBlock*, 8>&,
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DenseMap<MachineBasicBlock*, SmallVector<MachineOperand*, 4> >&,
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DenseMap<MachineBasicBlock*, SmallPtrSet<MachineInstr*, 4> >&,
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SmallVector<MachineBasicBlock*, 4>&);
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bool SplitRegLiveInterval(LiveInterval*);
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bool SplitRegLiveIntervals(const TargetRegisterClass **);
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};
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} // end anonymous namespace
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char PreAllocSplitting::ID = 0;
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static RegisterPass<PreAllocSplitting>
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X("pre-alloc-splitting", "Pre-Register Allocation Live Interval Splitting");
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const PassInfo *const llvm::PreAllocSplittingID = &X;
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/// findNextEmptySlot - Find a gap after the given machine instruction in the
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/// instruction index map. If there isn't one, return end().
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MachineBasicBlock::iterator
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PreAllocSplitting::findNextEmptySlot(MachineBasicBlock *MBB, MachineInstr *MI,
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unsigned &SpotIndex) {
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MachineBasicBlock::iterator MII = MI;
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if (++MII != MBB->end()) {
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unsigned Index = LIs->findGapBeforeInstr(LIs->getInstructionIndex(MII));
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if (Index) {
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SpotIndex = Index;
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return MII;
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}
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}
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return MBB->end();
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}
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/// findSpillPoint - Find a gap as far away from the given MI that's suitable
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/// for spilling the current live interval. The index must be before any
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/// defs and uses of the live interval register in the mbb. Return begin() if
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/// none is found.
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MachineBasicBlock::iterator
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PreAllocSplitting::findSpillPoint(MachineBasicBlock *MBB, MachineInstr *MI,
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SmallPtrSet<MachineInstr*, 4> &RefsInMBB,
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unsigned &SpillIndex) {
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MachineBasicBlock::iterator Pt = MBB->begin();
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// Go top down if RefsInMBB is empty.
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if (RefsInMBB.empty()) {
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MachineBasicBlock::iterator MII = MBB->begin();
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MachineBasicBlock::iterator EndPt = MI;
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do {
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++MII;
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unsigned Index = LIs->getInstructionIndex(MII);
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unsigned Gap = LIs->findGapBeforeInstr(Index);
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if (Gap) {
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Pt = MII;
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SpillIndex = Gap;
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break;
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}
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} while (MII != EndPt);
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} else {
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MachineBasicBlock::iterator MII = MI;
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while (MII != MBB->begin() && !RefsInMBB.count(MII)) {
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unsigned Index = LIs->getInstructionIndex(MII);
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if (LIs->hasGapBeforeInstr(Index)) {
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Pt = MII;
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SpillIndex = LIs->findGapBeforeInstr(Index, true);
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}
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--MII;
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}
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}
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return Pt;
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}
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/// findRestorePoint - Find a gap in the instruction index map that's suitable
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/// for restoring the current live interval value. The index must be before any
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/// uses of the live interval register in the mbb. Return end() if none is
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/// found.
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MachineBasicBlock::iterator
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PreAllocSplitting::findRestorePoint(MachineBasicBlock *MBB, MachineInstr *MI,
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unsigned LastIdx,
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SmallPtrSet<MachineInstr*, 4> &RefsInMBB,
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unsigned &RestoreIndex) {
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MachineBasicBlock::iterator Pt = MBB->end();
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unsigned EndIdx = LIs->getMBBEndIdx(MBB);
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// Go bottom up if RefsInMBB is empty and the end of the mbb isn't beyond
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// the last index in the live range.
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if (RefsInMBB.empty() && LastIdx >= EndIdx) {
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MachineBasicBlock::iterator MII = MBB->end();
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MachineBasicBlock::iterator EndPt = MI;
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do {
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--MII;
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unsigned Index = LIs->getInstructionIndex(MII);
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unsigned Gap = LIs->findGapBeforeInstr(Index);
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if (Gap) {
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Pt = MII;
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RestoreIndex = Gap;
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break;
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}
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} while (MII != EndPt);
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} else {
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MachineBasicBlock::iterator MII = MI;
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MII = ++MII;
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// FIXME: Limit the number of instructions to examine to reduce
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// compile time?
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while (MII != MBB->end()) {
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unsigned Index = LIs->getInstructionIndex(MII);
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if (Index > LastIdx)
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break;
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unsigned Gap = LIs->findGapBeforeInstr(Index);
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if (Gap) {
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Pt = MII;
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RestoreIndex = Gap;
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}
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if (RefsInMBB.count(MII))
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break;
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++MII;
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}
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}
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return Pt;
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}
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/// RecordSplit - Given a register live interval is split, remember the spill
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/// slot where the val#s are in.
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void PreAllocSplitting::RecordSplit(unsigned Reg, unsigned SpillIndex,
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unsigned RestoreIndex, int SS) {
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const LiveRange *LR = NULL;
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if (SpillIndex) {
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LR = CurrLI->getLiveRangeContaining(LIs->getUseIndex(SpillIndex));
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LIValNoSSMap.insert(std::make_pair(std::make_pair(CurrLI->reg,
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LR->valno->id), SS));
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}
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LR = CurrLI->getLiveRangeContaining(LIs->getDefIndex(RestoreIndex));
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LIValNoSSMap.insert(std::make_pair(std::make_pair(CurrLI->reg,
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LR->valno->id), SS));
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}
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/// isAlreadySplit - Return if a given val# of a register live interval is already
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/// split. Also return by reference the spill stock where the value is.
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bool PreAllocSplitting::isAlreadySplit(unsigned Reg, unsigned ValNoId, int &SS){
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std::map<std::pair<unsigned, unsigned>, int>::iterator I =
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LIValNoSSMap.find(std::make_pair(Reg, ValNoId));
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if (I == LIValNoSSMap.end())
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return false;
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SS = I->second;
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return true;
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}
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/// UpdateIntervalForSplit - Given the specified val# of the current live
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/// interval is being split, and the split and rejoin indices, update the live
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/// interval accordingly.
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void
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PreAllocSplitting::UpdateIntervalForSplit(VNInfo *ValNo, unsigned SplitIndex,
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unsigned JoinIndex) {
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SmallVector<std::pair<unsigned,unsigned>, 4> Before;
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SmallVector<std::pair<unsigned,unsigned>, 4> After;
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SmallVector<unsigned, 4> BeforeKills;
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SmallVector<unsigned, 4> AfterKills;
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SmallPtrSet<const LiveRange*, 4> Processed;
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// First, let's figure out which parts of the live interval is now defined
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// by the restore, which are defined by the original definition.
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const LiveRange *LR = CurrLI->getLiveRangeContaining(JoinIndex);
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After.push_back(std::make_pair(JoinIndex, LR->end));
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if (CurrLI->isKill(ValNo, LR->end))
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AfterKills.push_back(LR->end);
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assert(LR->contains(SplitIndex));
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if (SplitIndex > LR->start) {
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Before.push_back(std::make_pair(LR->start, SplitIndex));
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BeforeKills.push_back(SplitIndex);
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}
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Processed.insert(LR);
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SmallVector<MachineBasicBlock*, 4> WorkList;
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MachineBasicBlock *MBB = LIs->getMBBFromIndex(LR->end-1);
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for (MachineBasicBlock::succ_iterator SI = MBB->succ_begin(),
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SE = MBB->succ_end(); SI != SE; ++SI)
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WorkList.push_back(*SI);
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while (!WorkList.empty()) {
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MBB = WorkList.back();
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WorkList.pop_back();
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unsigned Idx = LIs->getMBBStartIdx(MBB);
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LR = CurrLI->getLiveRangeContaining(Idx);
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if (LR && LR->valno == ValNo && !Processed.count(LR)) {
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After.push_back(std::make_pair(LR->start, LR->end));
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if (CurrLI->isKill(ValNo, LR->end))
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AfterKills.push_back(LR->end);
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Idx = LIs->getMBBEndIdx(MBB);
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if (LR->end > Idx) {
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for (MachineBasicBlock::succ_iterator SI = MBB->succ_begin(),
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SE = MBB->succ_end(); SI != SE; ++SI)
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WorkList.push_back(*SI);
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if (LR->end > Idx+1) {
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MBB = LIs->getMBBFromIndex(LR->end-1);
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for (MachineBasicBlock::succ_iterator SI = MBB->succ_begin(),
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SE = MBB->succ_end(); SI != SE; ++SI)
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WorkList.push_back(*SI);
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}
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}
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Processed.insert(LR);
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}
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}
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for (LiveInterval::iterator I = CurrLI->begin(), E = CurrLI->end();
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I != E; ++I) {
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LiveRange *LR = I;
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if (LR->valno == ValNo && !Processed.count(LR)) {
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Before.push_back(std::make_pair(LR->start, LR->end));
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if (CurrLI->isKill(ValNo, LR->end))
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BeforeKills.push_back(LR->end);
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}
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}
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// Now create new val#s to represent the live ranges defined by the old def
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// those defined by the restore.
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unsigned AfterDef = ValNo->def;
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MachineInstr *AfterCopy = ValNo->copy;
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bool HasPHIKill = ValNo->hasPHIKill;
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CurrLI->removeValNo(ValNo);
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VNInfo *BValNo = (Before.empty())
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? NULL
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: CurrLI->getNextValue(AfterDef, AfterCopy, LIs->getVNInfoAllocator());
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if (BValNo)
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CurrLI->addKills(BValNo, BeforeKills);
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VNInfo *AValNo = (After.empty())
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? NULL
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: CurrLI->getNextValue(JoinIndex,0, LIs->getVNInfoAllocator());
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if (AValNo) {
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AValNo->hasPHIKill = HasPHIKill;
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CurrLI->addKills(AValNo, AfterKills);
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}
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for (unsigned i = 0, e = Before.size(); i != e; ++i) {
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unsigned Start = Before[i].first;
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unsigned End = Before[i].second;
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CurrLI->addRange(LiveRange(Start, End, BValNo));
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}
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for (unsigned i = 0, e = After.size(); i != e; ++i) {
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unsigned Start = After[i].first;
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unsigned End = After[i].second;
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CurrLI->addRange(LiveRange(Start, End, AValNo));
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}
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}
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/// ShrinkWrapToLastUse - There are uses of the current live interval in the
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/// given block, shrink wrap the live interval to the last use (i.e. remove
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/// from last use to the end of the mbb). In case mbb is the where the barrier
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/// is, remove from the last use to the barrier.
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bool
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PreAllocSplitting::ShrinkWrapToLastUse(MachineBasicBlock *MBB,
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SmallVector<MachineOperand*, 4> &Uses,
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SmallPtrSet<MachineInstr*, 4> &UseMIs) {
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MachineOperand *LastMO = 0;
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MachineInstr *LastMI = 0;
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if (MBB != BarrierMBB && Uses.size() == 1) {
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// Single use, no need to traverse the block. We can't assume this for the
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// barrier bb though since the use is probably below the barrier.
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LastMO = Uses[0];
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LastMI = LastMO->getParent();
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} else {
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MachineBasicBlock::iterator MEE = MBB->begin();
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MachineBasicBlock::iterator MII;
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if (MBB == BarrierMBB)
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MII = Barrier;
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else
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MII = MBB->end();
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while (--MII != MEE) {
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MachineInstr *UseMI = &*MII;
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if (!UseMIs.count(UseMI))
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continue;
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for (unsigned i = 0, e = UseMI->getNumOperands(); i != e; ++i) {
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MachineOperand &MO = UseMI->getOperand(i);
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if (MO.isReg() && MO.getReg() == CurrLI->reg) {
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LastMO = &MO;
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break;
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}
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}
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LastMI = UseMI;
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break;
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}
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}
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// Cut off live range from last use (or beginning of the mbb if there
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// are no uses in it) to the end of the mbb.
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unsigned RangeStart, RangeEnd = LIs->getMBBEndIdx(MBB)+1;
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if (LastMI) {
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RangeStart = LIs->getUseIndex(LIs->getInstructionIndex(LastMI))+1;
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assert(!LastMO->isKill() && "Last use already terminates the interval?");
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LastMO->setIsKill();
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} else {
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assert(MBB == BarrierMBB);
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RangeStart = LIs->getMBBStartIdx(MBB);
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}
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if (MBB == BarrierMBB)
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RangeEnd = LIs->getUseIndex(BarrierIdx)+1;
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CurrLI->removeRange(RangeStart, RangeEnd);
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// Return true if the last use becomes a new kill.
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return LastMI;
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}
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/// ShrinkWrapLiveInterval - Recursively traverse the predecessor
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/// chain to find the new 'kills' and shrink wrap the live interval to the
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/// new kill indices.
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void
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PreAllocSplitting::ShrinkWrapLiveInterval(VNInfo *ValNo, MachineBasicBlock *MBB,
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MachineBasicBlock *SuccMBB, MachineBasicBlock *DefMBB,
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SmallPtrSet<MachineBasicBlock*, 8> &Visited,
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DenseMap<MachineBasicBlock*, SmallVector<MachineOperand*, 4> > &Uses,
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DenseMap<MachineBasicBlock*, SmallPtrSet<MachineInstr*, 4> > &UseMIs,
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SmallVector<MachineBasicBlock*, 4> &UseMBBs) {
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if (Visited.count(MBB))
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return;
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// If live interval is live in another successor path, then we can't process
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// this block. But we may able to do so after all the successors have been
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// processed.
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if (MBB != BarrierMBB) {
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for (MachineBasicBlock::succ_iterator SI = MBB->succ_begin(),
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SE = MBB->succ_end(); SI != SE; ++SI) {
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MachineBasicBlock *SMBB = *SI;
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if (SMBB == SuccMBB)
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continue;
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if (CurrLI->liveAt(LIs->getMBBStartIdx(SMBB)))
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return;
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}
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}
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Visited.insert(MBB);
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DenseMap<MachineBasicBlock*, SmallVector<MachineOperand*, 4> >::iterator
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UMII = Uses.find(MBB);
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if (UMII != Uses.end()) {
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// At least one use in this mbb, lets look for the kill.
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DenseMap<MachineBasicBlock*, SmallPtrSet<MachineInstr*, 4> >::iterator
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UMII2 = UseMIs.find(MBB);
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if (ShrinkWrapToLastUse(MBB, UMII->second, UMII2->second))
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// Found a kill, shrink wrapping of this path ends here.
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return;
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} else if (MBB == DefMBB) {
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assert(LIValNoSSMap.find(std::make_pair(CurrLI->reg, ValNo->id)) !=
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LIValNoSSMap.end() && "Why wasn't def spilled?");
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|
// There are no uses after the def.
|
|
MachineInstr *DefMI = LIs->getInstructionFromIndex(ValNo->def);
|
|
assert(RestoreMIs.count(DefMI) && "Not defined by a join?");
|
|
if (UseMBBs.empty()) {
|
|
// The only use must be below barrier in the barrier block. It's safe to
|
|
// remove the def.
|
|
LIs->RemoveMachineInstrFromMaps(DefMI);
|
|
DefMI->eraseFromParent();
|
|
CurrLI->removeRange(ValNo->def, LIs->getMBBEndIdx(MBB)+1);
|
|
}
|
|
} else if (MBB == BarrierMBB) {
|
|
// Remove entire live range from start of mbb to barrier.
|
|
CurrLI->removeRange(LIs->getMBBStartIdx(MBB),
|
|
LIs->getUseIndex(BarrierIdx)+1);
|
|
} else {
|
|
// Remove entire live range of the mbb out of the live interval.
|
|
CurrLI->removeRange(LIs->getMBBStartIdx(MBB), LIs->getMBBEndIdx(MBB)+1);
|
|
}
|
|
|
|
if (MBB == DefMBB)
|
|
// Reached the def mbb, stop traversing this path further.
|
|
return;
|
|
|
|
// Traverse the pathes up the predecessor chains further.
|
|
for (MachineBasicBlock::pred_iterator PI = MBB->pred_begin(),
|
|
PE = MBB->pred_end(); PI != PE; ++PI) {
|
|
MachineBasicBlock *Pred = *PI;
|
|
if (Pred == MBB)
|
|
continue;
|
|
if (Pred == DefMBB && ValNo->hasPHIKill)
|
|
// Pred is the def bb and the def reaches other val#s, we must
|
|
// allow the value to be live out of the bb.
|
|
continue;
|
|
ShrinkWrapLiveInterval(ValNo, Pred, MBB, DefMBB, Visited,
|
|
Uses, UseMIs, UseMBBs);
|
|
}
|
|
|
|
return;
|
|
}
|
|
|
|
/// SplitRegLiveInterval - Split (spill and restore) the given live interval
|
|
/// so it would not cross the barrier that's being processed. Shrink wrap
|
|
/// (minimize) the live interval to the last uses.
|
|
bool PreAllocSplitting::SplitRegLiveInterval(LiveInterval *LI) {
|
|
CurrLI = LI;
|
|
|
|
// Find live range where current interval cross the barrier.
|
|
LiveInterval::iterator LR =
|
|
CurrLI->FindLiveRangeContaining(LIs->getUseIndex(BarrierIdx));
|
|
VNInfo *ValNo = LR->valno;
|
|
|
|
if (ValNo->def == ~1U) {
|
|
// Defined by a dead def? How can this be?
|
|
assert(0 && "Val# is defined by a dead def?");
|
|
abort();
|
|
}
|
|
|
|
// FIXME: For now, if definition is rematerializable, do not split.
|
|
MachineInstr *DefMI = (ValNo->def != ~0U)
|
|
? LIs->getInstructionFromIndex(ValNo->def) : NULL;
|
|
if (DefMI && LIs->isReMaterializable(*LI, ValNo, DefMI))
|
|
return false;
|
|
|
|
// Find all references in the barrier mbb.
|
|
SmallPtrSet<MachineInstr*, 4> RefsInMBB;
|
|
for (MachineRegisterInfo::reg_iterator I = MRI->reg_begin(CurrLI->reg),
|
|
E = MRI->reg_end(); I != E; ++I) {
|
|
MachineInstr *RefMI = &*I;
|
|
if (RefMI->getParent() == BarrierMBB)
|
|
RefsInMBB.insert(RefMI);
|
|
}
|
|
|
|
// Find a point to restore the value after the barrier.
|
|
unsigned RestoreIndex;
|
|
MachineBasicBlock::iterator RestorePt =
|
|
findRestorePoint(BarrierMBB, Barrier, LR->end, RefsInMBB, RestoreIndex);
|
|
if (RestorePt == BarrierMBB->end())
|
|
return false;
|
|
|
|
// Add a spill either before the barrier or after the definition.
|
|
MachineBasicBlock *DefMBB = DefMI ? DefMI->getParent() : NULL;
|
|
const TargetRegisterClass *RC = MRI->getRegClass(CurrLI->reg);
|
|
unsigned SpillIndex = 0;
|
|
MachineInstr *SpillMI = NULL;
|
|
int SS = -1;
|
|
bool PrevSpilled = isAlreadySplit(CurrLI->reg, ValNo->id, SS);
|
|
if (ValNo->def == ~0U) {
|
|
// If it's defined by a phi, we must split just before the barrier.
|
|
MachineBasicBlock::iterator SpillPt =
|
|
findSpillPoint(BarrierMBB, Barrier, RefsInMBB, SpillIndex);
|
|
if (SpillPt == BarrierMBB->begin())
|
|
return false; // No gap to insert spill.
|
|
// Add spill.
|
|
if (!PrevSpilled)
|
|
// If previously split, reuse the spill slot.
|
|
SS = MFI->CreateStackObject(RC->getSize(), RC->getAlignment());
|
|
TII->storeRegToStackSlot(*BarrierMBB, SpillPt, CurrLI->reg, true, SS, RC);
|
|
SpillMI = prior(SpillPt);
|
|
LIs->InsertMachineInstrInMaps(SpillMI, SpillIndex);
|
|
} else if (!PrevSpilled) {
|
|
if (!DefMI)
|
|
// Def is dead. Do nothing.
|
|
return false;
|
|
// If it's already split, just restore the value. There is no need to spill
|
|
// the def again.
|
|
// Check if it's possible to insert a spill after the def MI.
|
|
MachineBasicBlock::iterator SpillPt =
|
|
findNextEmptySlot(DefMBB, DefMI, SpillIndex);
|
|
if (SpillPt == DefMBB->end())
|
|
return false; // No gap to insert spill.
|
|
SS = MFI->CreateStackObject(RC->getSize(), RC->getAlignment());
|
|
|
|
// Add spill. The store instruction kills the register if def is before
|
|
// the barrier in the barrier block.
|
|
TII->storeRegToStackSlot(*DefMBB, SpillPt, CurrLI->reg,
|
|
DefMBB == BarrierMBB, SS, RC);
|
|
SpillMI = prior(SpillPt);
|
|
LIs->InsertMachineInstrInMaps(SpillMI, SpillIndex);
|
|
}
|
|
|
|
// Add restore.
|
|
// FIXME: Create live interval for stack slot.
|
|
TII->loadRegFromStackSlot(*BarrierMBB, RestorePt, CurrLI->reg, SS, RC);
|
|
MachineInstr *LoadMI = prior(RestorePt);
|
|
LIs->InsertMachineInstrInMaps(LoadMI, RestoreIndex);
|
|
RestoreMIs.insert(LoadMI);
|
|
|
|
// If live interval is spilled in the same block as the barrier, just
|
|
// create a hole in the interval.
|
|
if (!DefMBB ||
|
|
(SpillMI && SpillMI->getParent() == BarrierMBB)) {
|
|
UpdateIntervalForSplit(ValNo, LIs->getUseIndex(SpillIndex)+1,
|
|
LIs->getDefIndex(RestoreIndex));
|
|
|
|
// Record val# values are in the specific spill slot.
|
|
RecordSplit(CurrLI->reg, SpillIndex, RestoreIndex, SS);
|
|
|
|
++NumSplit;
|
|
return true;
|
|
}
|
|
|
|
// Shrink wrap the live interval by walking up the CFG and find the
|
|
// new kills.
|
|
// Now let's find all the uses of the val#.
|
|
DenseMap<MachineBasicBlock*, SmallVector<MachineOperand*, 4> > Uses;
|
|
DenseMap<MachineBasicBlock*, SmallPtrSet<MachineInstr*, 4> > UseMIs;
|
|
SmallPtrSet<MachineBasicBlock*, 4> Seen;
|
|
SmallVector<MachineBasicBlock*, 4> UseMBBs;
|
|
for (MachineRegisterInfo::use_iterator UI = MRI->use_begin(CurrLI->reg),
|
|
UE = MRI->use_end(); UI != UE; ++UI) {
|
|
MachineOperand &UseMO = UI.getOperand();
|
|
MachineInstr *UseMI = UseMO.getParent();
|
|
unsigned UseIdx = LIs->getInstructionIndex(UseMI);
|
|
LiveInterval::iterator ULR = CurrLI->FindLiveRangeContaining(UseIdx);
|
|
if (ULR->valno != ValNo)
|
|
continue;
|
|
MachineBasicBlock *UseMBB = UseMI->getParent();
|
|
// Remember which other mbb's use this val#.
|
|
if (Seen.insert(UseMBB) && UseMBB != BarrierMBB)
|
|
UseMBBs.push_back(UseMBB);
|
|
DenseMap<MachineBasicBlock*, SmallVector<MachineOperand*, 4> >::iterator
|
|
UMII = Uses.find(UseMBB);
|
|
if (UMII != Uses.end()) {
|
|
DenseMap<MachineBasicBlock*, SmallPtrSet<MachineInstr*, 4> >::iterator
|
|
UMII2 = UseMIs.find(UseMBB);
|
|
UMII->second.push_back(&UseMO);
|
|
UMII2->second.insert(UseMI);
|
|
} else {
|
|
SmallVector<MachineOperand*, 4> Ops;
|
|
Ops.push_back(&UseMO);
|
|
Uses.insert(std::make_pair(UseMBB, Ops));
|
|
SmallPtrSet<MachineInstr*, 4> MIs;
|
|
MIs.insert(UseMI);
|
|
UseMIs.insert(std::make_pair(UseMBB, MIs));
|
|
}
|
|
}
|
|
|
|
// Walk up the predecessor chains.
|
|
SmallPtrSet<MachineBasicBlock*, 8> Visited;
|
|
ShrinkWrapLiveInterval(ValNo, BarrierMBB, NULL, DefMBB, Visited,
|
|
Uses, UseMIs, UseMBBs);
|
|
|
|
// Remove live range from barrier to the restore. FIXME: Find a better
|
|
// point to re-start the live interval.
|
|
UpdateIntervalForSplit(ValNo, LIs->getUseIndex(BarrierIdx)+1,
|
|
LIs->getDefIndex(RestoreIndex));
|
|
// Record val# values are in the specific spill slot.
|
|
RecordSplit(CurrLI->reg, SpillIndex, RestoreIndex, SS);
|
|
|
|
++NumSplit;
|
|
return true;
|
|
}
|
|
|
|
/// SplitRegLiveIntervals - Split all register live intervals that cross the
|
|
/// barrier that's being processed.
|
|
bool
|
|
PreAllocSplitting::SplitRegLiveIntervals(const TargetRegisterClass **RCs) {
|
|
// First find all the virtual registers whose live intervals are intercepted
|
|
// by the current barrier.
|
|
SmallVector<LiveInterval*, 8> Intervals;
|
|
for (const TargetRegisterClass **RC = RCs; *RC; ++RC) {
|
|
if (TII->IgnoreRegisterClassBarriers(*RC))
|
|
continue;
|
|
std::vector<unsigned> &VRs = MRI->getRegClassVirtRegs(*RC);
|
|
for (unsigned i = 0, e = VRs.size(); i != e; ++i) {
|
|
unsigned Reg = VRs[i];
|
|
if (!LIs->hasInterval(Reg))
|
|
continue;
|
|
LiveInterval *LI = &LIs->getInterval(Reg);
|
|
if (LI->liveAt(BarrierIdx) && !Barrier->readsRegister(Reg))
|
|
// Virtual register live interval is intercepted by the barrier. We
|
|
// should split and shrink wrap its interval if possible.
|
|
Intervals.push_back(LI);
|
|
}
|
|
}
|
|
|
|
// Process the affected live intervals.
|
|
bool Change = false;
|
|
while (!Intervals.empty()) {
|
|
LiveInterval *LI = Intervals.back();
|
|
Intervals.pop_back();
|
|
Change |= SplitRegLiveInterval(LI);
|
|
}
|
|
|
|
return Change;
|
|
}
|
|
|
|
bool PreAllocSplitting::runOnMachineFunction(MachineFunction &MF) {
|
|
CurMF = &MF;
|
|
TM = &MF.getTarget();
|
|
TII = TM->getInstrInfo();
|
|
MFI = MF.getFrameInfo();
|
|
MRI = &MF.getRegInfo();
|
|
LIs = &getAnalysis<LiveIntervals>();
|
|
|
|
bool MadeChange = false;
|
|
|
|
// Make sure blocks are numbered in order.
|
|
MF.RenumberBlocks();
|
|
|
|
for (MachineFunction::reverse_iterator I = MF.rbegin(), E = MF.rend();
|
|
I != E; ++I) {
|
|
BarrierMBB = &*I;
|
|
for (MachineBasicBlock::reverse_iterator II = BarrierMBB->rbegin(),
|
|
EE = BarrierMBB->rend(); II != EE; ++II) {
|
|
Barrier = &*II;
|
|
const TargetRegisterClass **BarrierRCs =
|
|
Barrier->getDesc().getRegClassBarriers();
|
|
if (!BarrierRCs)
|
|
continue;
|
|
BarrierIdx = LIs->getInstructionIndex(Barrier);
|
|
MadeChange |= SplitRegLiveIntervals(BarrierRCs);
|
|
}
|
|
}
|
|
|
|
return MadeChange;
|
|
}
|