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Diffstat (limited to 'contrib/llvm/lib/CodeGen/SplitKit.h')
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diff --git a/contrib/llvm/lib/CodeGen/SplitKit.h b/contrib/llvm/lib/CodeGen/SplitKit.h deleted file mode 100644 index 86ad3811e3ad..000000000000 --- a/contrib/llvm/lib/CodeGen/SplitKit.h +++ /dev/null @@ -1,564 +0,0 @@ -//===- SplitKit.h - Toolkit for splitting live ranges -----------*- C++ -*-===// -// -// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. -// See https://llvm.org/LICENSE.txt for license information. -// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception -// -//===----------------------------------------------------------------------===// -// -// This file contains the SplitAnalysis class as well as mutator functions for -// live range splitting. -// -//===----------------------------------------------------------------------===// - -#ifndef LLVM_LIB_CODEGEN_SPLITKIT_H -#define LLVM_LIB_CODEGEN_SPLITKIT_H - -#include "LiveRangeCalc.h" -#include "llvm/ADT/ArrayRef.h" -#include "llvm/ADT/BitVector.h" -#include "llvm/ADT/DenseMap.h" -#include "llvm/ADT/DenseSet.h" -#include "llvm/ADT/IntervalMap.h" -#include "llvm/ADT/PointerIntPair.h" -#include "llvm/ADT/SmallPtrSet.h" -#include "llvm/ADT/SmallVector.h" -#include "llvm/CodeGen/LiveInterval.h" -#include "llvm/CodeGen/LiveIntervals.h" -#include "llvm/CodeGen/MachineBasicBlock.h" -#include "llvm/CodeGen/MachineFunction.h" -#include "llvm/CodeGen/SlotIndexes.h" -#include "llvm/MC/LaneBitmask.h" -#include "llvm/Support/Compiler.h" -#include <utility> - -namespace llvm { - -class LiveIntervals; -class LiveRangeEdit; -class MachineBlockFrequencyInfo; -class MachineDominatorTree; -class MachineLoopInfo; -class MachineRegisterInfo; -class TargetInstrInfo; -class TargetRegisterInfo; -class VirtRegMap; - -/// Determines the latest safe point in a block in which we can insert a split, -/// spill or other instruction related with CurLI. -class LLVM_LIBRARY_VISIBILITY InsertPointAnalysis { -private: - const LiveIntervals &LIS; - - /// Last legal insert point in each basic block in the current function. - /// The first entry is the first terminator, the second entry is the - /// last valid point to insert a split or spill for a variable that is - /// live into a landing pad successor. - SmallVector<std::pair<SlotIndex, SlotIndex>, 8> LastInsertPoint; - - SlotIndex computeLastInsertPoint(const LiveInterval &CurLI, - const MachineBasicBlock &MBB); - -public: - InsertPointAnalysis(const LiveIntervals &lis, unsigned BBNum); - - /// Return the base index of the last valid insert point for \pCurLI in \pMBB. - SlotIndex getLastInsertPoint(const LiveInterval &CurLI, - const MachineBasicBlock &MBB) { - unsigned Num = MBB.getNumber(); - // Inline the common simple case. - if (LastInsertPoint[Num].first.isValid() && - !LastInsertPoint[Num].second.isValid()) - return LastInsertPoint[Num].first; - return computeLastInsertPoint(CurLI, MBB); - } - - /// Returns the last insert point as an iterator for \pCurLI in \pMBB. - MachineBasicBlock::iterator getLastInsertPointIter(const LiveInterval &CurLI, - MachineBasicBlock &MBB); - - /// Return the base index of the first insert point in \pMBB. - SlotIndex getFirstInsertPoint(MachineBasicBlock &MBB) { - SlotIndex Res = LIS.getMBBStartIdx(&MBB); - if (!MBB.empty()) { - MachineBasicBlock::iterator MII = MBB.SkipPHIsLabelsAndDebug(MBB.begin()); - if (MII != MBB.end()) - Res = LIS.getInstructionIndex(*MII); - } - return Res; - } - -}; - -/// SplitAnalysis - Analyze a LiveInterval, looking for live range splitting -/// opportunities. -class LLVM_LIBRARY_VISIBILITY SplitAnalysis { -public: - const MachineFunction &MF; - const VirtRegMap &VRM; - const LiveIntervals &LIS; - const MachineLoopInfo &Loops; - const TargetInstrInfo &TII; - - /// Additional information about basic blocks where the current variable is - /// live. Such a block will look like one of these templates: - /// - /// 1. | o---x | Internal to block. Variable is only live in this block. - /// 2. |---x | Live-in, kill. - /// 3. | o---| Def, live-out. - /// 4. |---x o---| Live-in, kill, def, live-out. Counted by NumGapBlocks. - /// 5. |---o---o---| Live-through with uses or defs. - /// 6. |-----------| Live-through without uses. Counted by NumThroughBlocks. - /// - /// Two BlockInfo entries are created for template 4. One for the live-in - /// segment, and one for the live-out segment. These entries look as if the - /// block were split in the middle where the live range isn't live. - /// - /// Live-through blocks without any uses don't get BlockInfo entries. They - /// are simply listed in ThroughBlocks instead. - /// - struct BlockInfo { - MachineBasicBlock *MBB; - SlotIndex FirstInstr; ///< First instr accessing current reg. - SlotIndex LastInstr; ///< Last instr accessing current reg. - SlotIndex FirstDef; ///< First non-phi valno->def, or SlotIndex(). - bool LiveIn; ///< Current reg is live in. - bool LiveOut; ///< Current reg is live out. - - /// isOneInstr - Returns true when this BlockInfo describes a single - /// instruction. - bool isOneInstr() const { - return SlotIndex::isSameInstr(FirstInstr, LastInstr); - } - }; - -private: - // Current live interval. - const LiveInterval *CurLI = nullptr; - - /// Insert Point Analysis. - InsertPointAnalysis IPA; - - // Sorted slot indexes of using instructions. - SmallVector<SlotIndex, 8> UseSlots; - - /// UseBlocks - Blocks where CurLI has uses. - SmallVector<BlockInfo, 8> UseBlocks; - - /// NumGapBlocks - Number of duplicate entries in UseBlocks for blocks where - /// the live range has a gap. - unsigned NumGapBlocks; - - /// ThroughBlocks - Block numbers where CurLI is live through without uses. - BitVector ThroughBlocks; - - /// NumThroughBlocks - Number of live-through blocks. - unsigned NumThroughBlocks; - - /// DidRepairRange - analyze was forced to shrinkToUses(). - bool DidRepairRange; - - // Sumarize statistics by counting instructions using CurLI. - void analyzeUses(); - - /// calcLiveBlockInfo - Compute per-block information about CurLI. - bool calcLiveBlockInfo(); - -public: - SplitAnalysis(const VirtRegMap &vrm, const LiveIntervals &lis, - const MachineLoopInfo &mli); - - /// analyze - set CurLI to the specified interval, and analyze how it may be - /// split. - void analyze(const LiveInterval *li); - - /// didRepairRange() - Returns true if CurLI was invalid and has been repaired - /// by analyze(). This really shouldn't happen, but sometimes the coalescer - /// can create live ranges that end in mid-air. - bool didRepairRange() const { return DidRepairRange; } - - /// clear - clear all data structures so SplitAnalysis is ready to analyze a - /// new interval. - void clear(); - - /// getParent - Return the last analyzed interval. - const LiveInterval &getParent() const { return *CurLI; } - - /// isOriginalEndpoint - Return true if the original live range was killed or - /// (re-)defined at Idx. Idx should be the 'def' slot for a normal kill/def, - /// and 'use' for an early-clobber def. - /// This can be used to recognize code inserted by earlier live range - /// splitting. - bool isOriginalEndpoint(SlotIndex Idx) const; - - /// getUseSlots - Return an array of SlotIndexes of instructions using CurLI. - /// This include both use and def operands, at most one entry per instruction. - ArrayRef<SlotIndex> getUseSlots() const { return UseSlots; } - - /// getUseBlocks - Return an array of BlockInfo objects for the basic blocks - /// where CurLI has uses. - ArrayRef<BlockInfo> getUseBlocks() const { return UseBlocks; } - - /// getNumThroughBlocks - Return the number of through blocks. - unsigned getNumThroughBlocks() const { return NumThroughBlocks; } - - /// isThroughBlock - Return true if CurLI is live through MBB without uses. - bool isThroughBlock(unsigned MBB) const { return ThroughBlocks.test(MBB); } - - /// getThroughBlocks - Return the set of through blocks. - const BitVector &getThroughBlocks() const { return ThroughBlocks; } - - /// getNumLiveBlocks - Return the number of blocks where CurLI is live. - unsigned getNumLiveBlocks() const { - return getUseBlocks().size() - NumGapBlocks + getNumThroughBlocks(); - } - - /// countLiveBlocks - Return the number of blocks where li is live. This is - /// guaranteed to return the same number as getNumLiveBlocks() after calling - /// analyze(li). - unsigned countLiveBlocks(const LiveInterval *li) const; - - using BlockPtrSet = SmallPtrSet<const MachineBasicBlock *, 16>; - - /// shouldSplitSingleBlock - Returns true if it would help to create a local - /// live range for the instructions in BI. There is normally no benefit to - /// creating a live range for a single instruction, but it does enable - /// register class inflation if the instruction has a restricted register - /// class. - /// - /// @param BI The block to be isolated. - /// @param SingleInstrs True when single instructions should be isolated. - bool shouldSplitSingleBlock(const BlockInfo &BI, bool SingleInstrs) const; - - SlotIndex getLastSplitPoint(unsigned Num) { - return IPA.getLastInsertPoint(*CurLI, *MF.getBlockNumbered(Num)); - } - - MachineBasicBlock::iterator getLastSplitPointIter(MachineBasicBlock *BB) { - return IPA.getLastInsertPointIter(*CurLI, *BB); - } - - SlotIndex getFirstSplitPoint(unsigned Num) { - return IPA.getFirstInsertPoint(*MF.getBlockNumbered(Num)); - } -}; - -/// SplitEditor - Edit machine code and LiveIntervals for live range -/// splitting. -/// -/// - Create a SplitEditor from a SplitAnalysis. -/// - Start a new live interval with openIntv. -/// - Mark the places where the new interval is entered using enterIntv* -/// - Mark the ranges where the new interval is used with useIntv* -/// - Mark the places where the interval is exited with exitIntv*. -/// - Finish the current interval with closeIntv and repeat from 2. -/// - Rewrite instructions with finish(). -/// -class LLVM_LIBRARY_VISIBILITY SplitEditor { - SplitAnalysis &SA; - AliasAnalysis &AA; - LiveIntervals &LIS; - VirtRegMap &VRM; - MachineRegisterInfo &MRI; - MachineDominatorTree &MDT; - const TargetInstrInfo &TII; - const TargetRegisterInfo &TRI; - const MachineBlockFrequencyInfo &MBFI; - -public: - /// ComplementSpillMode - Select how the complement live range should be - /// created. SplitEditor automatically creates interval 0 to contain - /// anything that isn't added to another interval. This complement interval - /// can get quite complicated, and it can sometimes be an advantage to allow - /// it to overlap the other intervals. If it is going to spill anyway, no - /// registers are wasted by keeping a value in two places at the same time. - enum ComplementSpillMode { - /// SM_Partition(Default) - Try to create the complement interval so it - /// doesn't overlap any other intervals, and the original interval is - /// partitioned. This may require a large number of back copies and extra - /// PHI-defs. Only segments marked with overlapIntv will be overlapping. - SM_Partition, - - /// SM_Size - Overlap intervals to minimize the number of inserted COPY - /// instructions. Copies to the complement interval are hoisted to their - /// common dominator, so only one COPY is required per value in the - /// complement interval. This also means that no extra PHI-defs need to be - /// inserted in the complement interval. - SM_Size, - - /// SM_Speed - Overlap intervals to minimize the expected execution - /// frequency of the inserted copies. This is very similar to SM_Size, but - /// the complement interval may get some extra PHI-defs. - SM_Speed - }; - -private: - /// Edit - The current parent register and new intervals created. - LiveRangeEdit *Edit = nullptr; - - /// Index into Edit of the currently open interval. - /// The index 0 is used for the complement, so the first interval started by - /// openIntv will be 1. - unsigned OpenIdx = 0; - - /// The current spill mode, selected by reset(). - ComplementSpillMode SpillMode = SM_Partition; - - using RegAssignMap = IntervalMap<SlotIndex, unsigned>; - - /// Allocator for the interval map. This will eventually be shared with - /// SlotIndexes and LiveIntervals. - RegAssignMap::Allocator Allocator; - - /// RegAssign - Map of the assigned register indexes. - /// Edit.get(RegAssign.lookup(Idx)) is the register that should be live at - /// Idx. - RegAssignMap RegAssign; - - using ValueForcePair = PointerIntPair<VNInfo *, 1>; - using ValueMap = DenseMap<std::pair<unsigned, unsigned>, ValueForcePair>; - - /// Values - keep track of the mapping from parent values to values in the new - /// intervals. Given a pair (RegIdx, ParentVNI->id), Values contains: - /// - /// 1. No entry - the value is not mapped to Edit.get(RegIdx). - /// 2. (Null, false) - the value is mapped to multiple values in - /// Edit.get(RegIdx). Each value is represented by a minimal live range at - /// its def. The full live range can be inferred exactly from the range - /// of RegIdx in RegAssign. - /// 3. (Null, true). As above, but the ranges in RegAssign are too large, and - /// the live range must be recomputed using LiveRangeCalc::extend(). - /// 4. (VNI, false) The value is mapped to a single new value. - /// The new value has no live ranges anywhere. - ValueMap Values; - - /// LRCalc - Cache for computing live ranges and SSA update. Each instance - /// can only handle non-overlapping live ranges, so use a separate - /// LiveRangeCalc instance for the complement interval when in spill mode. - LiveRangeCalc LRCalc[2]; - - /// getLRCalc - Return the LRCalc to use for RegIdx. In spill mode, the - /// complement interval can overlap the other intervals, so it gets its own - /// LRCalc instance. When not in spill mode, all intervals can share one. - LiveRangeCalc &getLRCalc(unsigned RegIdx) { - return LRCalc[SpillMode != SM_Partition && RegIdx != 0]; - } - - /// Find a subrange corresponding to the lane mask @p LM in the live - /// interval @p LI. The interval @p LI is assumed to contain such a subrange. - /// This function is used to find corresponding subranges between the - /// original interval and the new intervals. - LiveInterval::SubRange &getSubRangeForMask(LaneBitmask LM, LiveInterval &LI); - - /// Add a segment to the interval LI for the value number VNI. If LI has - /// subranges, corresponding segments will be added to them as well, but - /// with newly created value numbers. If Original is true, dead def will - /// only be added a subrange of LI if the corresponding subrange of the - /// original interval has a def at this index. Otherwise, all subranges - /// of LI will be updated. - void addDeadDef(LiveInterval &LI, VNInfo *VNI, bool Original); - - /// defValue - define a value in RegIdx from ParentVNI at Idx. - /// Idx does not have to be ParentVNI->def, but it must be contained within - /// ParentVNI's live range in ParentLI. The new value is added to the value - /// map. The value being defined may either come from rematerialization - /// (or an inserted copy), or it may be coming from the original interval. - /// The parameter Original should be true in the latter case, otherwise - /// it should be false. - /// Return the new LI value. - VNInfo *defValue(unsigned RegIdx, const VNInfo *ParentVNI, SlotIndex Idx, - bool Original); - - /// forceRecompute - Force the live range of ParentVNI in RegIdx to be - /// recomputed by LiveRangeCalc::extend regardless of the number of defs. - /// This is used for values whose live range doesn't match RegAssign exactly. - /// They could have rematerialized, or back-copies may have been moved. - void forceRecompute(unsigned RegIdx, const VNInfo &ParentVNI); - - /// Calls forceRecompute() on any affected regidx and on ParentVNI - /// predecessors in case of a phi definition. - void forceRecomputeVNI(const VNInfo &ParentVNI); - - /// defFromParent - Define Reg from ParentVNI at UseIdx using either - /// rematerialization or a COPY from parent. Return the new value. - VNInfo *defFromParent(unsigned RegIdx, - VNInfo *ParentVNI, - SlotIndex UseIdx, - MachineBasicBlock &MBB, - MachineBasicBlock::iterator I); - - /// removeBackCopies - Remove the copy instructions that defines the values - /// in the vector in the complement interval. - void removeBackCopies(SmallVectorImpl<VNInfo*> &Copies); - - /// getShallowDominator - Returns the least busy dominator of MBB that is - /// also dominated by DefMBB. Busy is measured by loop depth. - MachineBasicBlock *findShallowDominator(MachineBasicBlock *MBB, - MachineBasicBlock *DefMBB); - - /// Find out all the backCopies dominated by others. - void computeRedundantBackCopies(DenseSet<unsigned> &NotToHoistSet, - SmallVectorImpl<VNInfo *> &BackCopies); - - /// Hoist back-copies to the complement interval. It tries to hoist all - /// the back-copies to one BB if it is beneficial, or else simply remove - /// redundant backcopies dominated by others. - void hoistCopies(); - - /// transferValues - Transfer values to the new ranges. - /// Return true if any ranges were skipped. - bool transferValues(); - - /// Live range @p LR corresponding to the lane Mask @p LM has a live - /// PHI def at the beginning of block @p B. Extend the range @p LR of - /// all predecessor values that reach this def. If @p LR is a subrange, - /// the array @p Undefs is the set of all locations where it is undefined - /// via <def,read-undef> in other subranges for the same register. - void extendPHIRange(MachineBasicBlock &B, LiveRangeCalc &LRC, - LiveRange &LR, LaneBitmask LM, - ArrayRef<SlotIndex> Undefs); - - /// extendPHIKillRanges - Extend the ranges of all values killed by original - /// parent PHIDefs. - void extendPHIKillRanges(); - - /// rewriteAssigned - Rewrite all uses of Edit.getReg() to assigned registers. - void rewriteAssigned(bool ExtendRanges); - - /// deleteRematVictims - Delete defs that are dead after rematerializing. - void deleteRematVictims(); - - /// Add a copy instruction copying \p FromReg to \p ToReg before - /// \p InsertBefore. This can be invoked with a \p LaneMask which may make it - /// necessary to construct a sequence of copies to cover it exactly. - SlotIndex buildCopy(unsigned FromReg, unsigned ToReg, LaneBitmask LaneMask, - MachineBasicBlock &MBB, MachineBasicBlock::iterator InsertBefore, - bool Late, unsigned RegIdx); - - SlotIndex buildSingleSubRegCopy(unsigned FromReg, unsigned ToReg, - MachineBasicBlock &MB, MachineBasicBlock::iterator InsertBefore, - unsigned SubIdx, LiveInterval &DestLI, bool Late, SlotIndex Def); - -public: - /// Create a new SplitEditor for editing the LiveInterval analyzed by SA. - /// Newly created intervals will be appended to newIntervals. - SplitEditor(SplitAnalysis &sa, AliasAnalysis &aa, LiveIntervals &lis, - VirtRegMap &vrm, MachineDominatorTree &mdt, - MachineBlockFrequencyInfo &mbfi); - - /// reset - Prepare for a new split. - void reset(LiveRangeEdit&, ComplementSpillMode = SM_Partition); - - /// Create a new virtual register and live interval. - /// Return the interval index, starting from 1. Interval index 0 is the - /// implicit complement interval. - unsigned openIntv(); - - /// currentIntv - Return the current interval index. - unsigned currentIntv() const { return OpenIdx; } - - /// selectIntv - Select a previously opened interval index. - void selectIntv(unsigned Idx); - - /// enterIntvBefore - Enter the open interval before the instruction at Idx. - /// If the parent interval is not live before Idx, a COPY is not inserted. - /// Return the beginning of the new live range. - SlotIndex enterIntvBefore(SlotIndex Idx); - - /// enterIntvAfter - Enter the open interval after the instruction at Idx. - /// Return the beginning of the new live range. - SlotIndex enterIntvAfter(SlotIndex Idx); - - /// enterIntvAtEnd - Enter the open interval at the end of MBB. - /// Use the open interval from the inserted copy to the MBB end. - /// Return the beginning of the new live range. - SlotIndex enterIntvAtEnd(MachineBasicBlock &MBB); - - /// useIntv - indicate that all instructions in MBB should use OpenLI. - void useIntv(const MachineBasicBlock &MBB); - - /// useIntv - indicate that all instructions in range should use OpenLI. - void useIntv(SlotIndex Start, SlotIndex End); - - /// leaveIntvAfter - Leave the open interval after the instruction at Idx. - /// Return the end of the live range. - SlotIndex leaveIntvAfter(SlotIndex Idx); - - /// leaveIntvBefore - Leave the open interval before the instruction at Idx. - /// Return the end of the live range. - SlotIndex leaveIntvBefore(SlotIndex Idx); - - /// leaveIntvAtTop - Leave the interval at the top of MBB. - /// Add liveness from the MBB top to the copy. - /// Return the end of the live range. - SlotIndex leaveIntvAtTop(MachineBasicBlock &MBB); - - /// overlapIntv - Indicate that all instructions in range should use the open - /// interval, but also let the complement interval be live. - /// - /// This doubles the register pressure, but is sometimes required to deal with - /// register uses after the last valid split point. - /// - /// The Start index should be a return value from a leaveIntv* call, and End - /// should be in the same basic block. The parent interval must have the same - /// value across the range. - /// - void overlapIntv(SlotIndex Start, SlotIndex End); - - /// finish - after all the new live ranges have been created, compute the - /// remaining live range, and rewrite instructions to use the new registers. - /// @param LRMap When not null, this vector will map each live range in Edit - /// back to the indices returned by openIntv. - /// There may be extra indices created by dead code elimination. - void finish(SmallVectorImpl<unsigned> *LRMap = nullptr); - - /// dump - print the current interval mapping to dbgs(). - void dump() const; - - // ===--- High level methods ---=== - - /// splitSingleBlock - Split CurLI into a separate live interval around the - /// uses in a single block. This is intended to be used as part of a larger - /// split, and doesn't call finish(). - void splitSingleBlock(const SplitAnalysis::BlockInfo &BI); - - /// splitLiveThroughBlock - Split CurLI in the given block such that it - /// enters the block in IntvIn and leaves it in IntvOut. There may be uses in - /// the block, but they will be ignored when placing split points. - /// - /// @param MBBNum Block number. - /// @param IntvIn Interval index entering the block. - /// @param LeaveBefore When set, leave IntvIn before this point. - /// @param IntvOut Interval index leaving the block. - /// @param EnterAfter When set, enter IntvOut after this point. - void splitLiveThroughBlock(unsigned MBBNum, - unsigned IntvIn, SlotIndex LeaveBefore, - unsigned IntvOut, SlotIndex EnterAfter); - - /// splitRegInBlock - Split CurLI in the given block such that it enters the - /// block in IntvIn and leaves it on the stack (or not at all). Split points - /// are placed in a way that avoids putting uses in the stack interval. This - /// may require creating a local interval when there is interference. - /// - /// @param BI Block descriptor. - /// @param IntvIn Interval index entering the block. Not 0. - /// @param LeaveBefore When set, leave IntvIn before this point. - void splitRegInBlock(const SplitAnalysis::BlockInfo &BI, - unsigned IntvIn, SlotIndex LeaveBefore); - - /// splitRegOutBlock - Split CurLI in the given block such that it enters the - /// block on the stack (or isn't live-in at all) and leaves it in IntvOut. - /// Split points are placed to avoid interference and such that the uses are - /// not in the stack interval. This may require creating a local interval - /// when there is interference. - /// - /// @param BI Block descriptor. - /// @param IntvOut Interval index leaving the block. - /// @param EnterAfter When set, enter IntvOut after this point. - void splitRegOutBlock(const SplitAnalysis::BlockInfo &BI, - unsigned IntvOut, SlotIndex EnterAfter); -}; - -} // end namespace llvm - -#endif // LLVM_LIB_CODEGEN_SPLITKIT_H |