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The old naming scheme (load/use/def/store) can be traced back to an old linear scan article, but the names don't match how slots are actually used. The load and store slots are not needed after the deferred spill code insertion framework was deleted. The use and def slots don't make any sense because we are using half-open intervals as is customary in C code, but the names suggest closed intervals. In reality, these slots were used to distinguish early-clobber defs from normal defs. The new naming scheme also has 4 slots, but the names match how the slots are really used. This is a purely mechanical renaming, but some of the code makes a lot more sense now. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@144503 91177308-0d34-0410-b5e6-96231b3b80d8
197 lines
6.3 KiB
C++
197 lines
6.3 KiB
C++
//===-- llvm/CodeGen/Spiller.cpp - Spiller -------------------------------===//
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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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#define DEBUG_TYPE "spiller"
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#include "Spiller.h"
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#include "VirtRegMap.h"
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#include "LiveRangeEdit.h"
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#include "llvm/CodeGen/LiveIntervalAnalysis.h"
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#include "llvm/CodeGen/LiveStackAnalysis.h"
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#include "llvm/CodeGen/MachineFrameInfo.h"
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#include "llvm/CodeGen/MachineFunction.h"
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#include "llvm/CodeGen/MachineInstrBuilder.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/Target/TargetMachine.h"
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#include "llvm/Target/TargetInstrInfo.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/Support/ErrorHandling.h"
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#include "llvm/Support/raw_ostream.h"
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using namespace llvm;
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namespace {
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enum SpillerName { trivial, inline_ };
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}
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static cl::opt<SpillerName>
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spillerOpt("spiller",
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cl::desc("Spiller to use: (default: standard)"),
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cl::Prefix,
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cl::values(clEnumVal(trivial, "trivial spiller"),
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clEnumValN(inline_, "inline", "inline spiller"),
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clEnumValEnd),
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cl::init(trivial));
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// Spiller virtual destructor implementation.
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Spiller::~Spiller() {}
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namespace {
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/// Utility class for spillers.
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class SpillerBase : public Spiller {
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protected:
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MachineFunctionPass *pass;
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MachineFunction *mf;
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VirtRegMap *vrm;
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LiveIntervals *lis;
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MachineFrameInfo *mfi;
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MachineRegisterInfo *mri;
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const TargetInstrInfo *tii;
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const TargetRegisterInfo *tri;
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/// Construct a spiller base.
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SpillerBase(MachineFunctionPass &pass, MachineFunction &mf, VirtRegMap &vrm)
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: pass(&pass), mf(&mf), vrm(&vrm)
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{
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lis = &pass.getAnalysis<LiveIntervals>();
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mfi = mf.getFrameInfo();
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mri = &mf.getRegInfo();
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tii = mf.getTarget().getInstrInfo();
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tri = mf.getTarget().getRegisterInfo();
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}
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/// Add spill ranges for every use/def of the live interval, inserting loads
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/// immediately before each use, and stores after each def. No folding or
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/// remat is attempted.
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void trivialSpillEverywhere(LiveInterval *li,
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SmallVectorImpl<LiveInterval*> &newIntervals) {
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DEBUG(dbgs() << "Spilling everywhere " << *li << "\n");
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assert(li->weight != HUGE_VALF &&
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"Attempting to spill already spilled value.");
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assert(!TargetRegisterInfo::isStackSlot(li->reg) &&
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"Trying to spill a stack slot.");
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DEBUG(dbgs() << "Trivial spill everywhere of reg" << li->reg << "\n");
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const TargetRegisterClass *trc = mri->getRegClass(li->reg);
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unsigned ss = vrm->assignVirt2StackSlot(li->reg);
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// Iterate over reg uses/defs.
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for (MachineRegisterInfo::reg_iterator
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regItr = mri->reg_begin(li->reg); regItr != mri->reg_end();) {
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// Grab the use/def instr.
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MachineInstr *mi = &*regItr;
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DEBUG(dbgs() << " Processing " << *mi);
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// Step regItr to the next use/def instr.
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do {
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++regItr;
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} while (regItr != mri->reg_end() && (&*regItr == mi));
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// Collect uses & defs for this instr.
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SmallVector<unsigned, 2> indices;
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bool hasUse = false;
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bool hasDef = false;
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for (unsigned i = 0; i != mi->getNumOperands(); ++i) {
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MachineOperand &op = mi->getOperand(i);
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if (!op.isReg() || op.getReg() != li->reg)
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continue;
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hasUse |= mi->getOperand(i).isUse();
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hasDef |= mi->getOperand(i).isDef();
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indices.push_back(i);
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}
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// Create a new vreg & interval for this instr.
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unsigned newVReg = mri->createVirtualRegister(trc);
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vrm->grow();
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vrm->assignVirt2StackSlot(newVReg, ss);
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LiveInterval *newLI = &lis->getOrCreateInterval(newVReg);
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newLI->weight = HUGE_VALF;
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// Update the reg operands & kill flags.
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for (unsigned i = 0; i < indices.size(); ++i) {
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unsigned mopIdx = indices[i];
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MachineOperand &mop = mi->getOperand(mopIdx);
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mop.setReg(newVReg);
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if (mop.isUse() && !mi->isRegTiedToDefOperand(mopIdx)) {
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mop.setIsKill(true);
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}
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}
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assert(hasUse || hasDef);
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// Insert reload if necessary.
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MachineBasicBlock::iterator miItr(mi);
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if (hasUse) {
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tii->loadRegFromStackSlot(*mi->getParent(), miItr, newVReg, ss, trc,
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tri);
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MachineInstr *loadInstr(prior(miItr));
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SlotIndex loadIndex =
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lis->InsertMachineInstrInMaps(loadInstr).getRegSlot();
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SlotIndex endIndex = loadIndex.getNextIndex();
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VNInfo *loadVNI =
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newLI->getNextValue(loadIndex, 0, lis->getVNInfoAllocator());
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newLI->addRange(LiveRange(loadIndex, endIndex, loadVNI));
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}
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// Insert store if necessary.
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if (hasDef) {
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tii->storeRegToStackSlot(*mi->getParent(), llvm::next(miItr), newVReg,
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true, ss, trc, tri);
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MachineInstr *storeInstr(llvm::next(miItr));
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SlotIndex storeIndex =
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lis->InsertMachineInstrInMaps(storeInstr).getRegSlot();
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SlotIndex beginIndex = storeIndex.getPrevIndex();
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VNInfo *storeVNI =
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newLI->getNextValue(beginIndex, 0, lis->getVNInfoAllocator());
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newLI->addRange(LiveRange(beginIndex, storeIndex, storeVNI));
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}
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newIntervals.push_back(newLI);
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}
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}
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};
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} // end anonymous namespace
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namespace {
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/// Spills any live range using the spill-everywhere method with no attempt at
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/// folding.
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class TrivialSpiller : public SpillerBase {
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public:
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TrivialSpiller(MachineFunctionPass &pass, MachineFunction &mf,
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VirtRegMap &vrm)
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: SpillerBase(pass, mf, vrm) {}
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void spill(LiveRangeEdit &LRE) {
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// Ignore spillIs - we don't use it.
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trivialSpillEverywhere(&LRE.getParent(), *LRE.getNewVRegs());
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}
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};
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} // end anonymous namespace
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llvm::Spiller* llvm::createSpiller(MachineFunctionPass &pass,
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MachineFunction &mf,
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VirtRegMap &vrm) {
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switch (spillerOpt) {
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default: assert(0 && "unknown spiller");
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case trivial: return new TrivialSpiller(pass, mf, vrm);
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case inline_: return createInlineSpiller(pass, mf, vrm);
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}
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}
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