LLVM 19.0.0git
Macros | Functions | Variables
ShrinkWrap.cpp File Reference
#include "llvm/ADT/BitVector.h"
#include "llvm/ADT/PostOrderIterator.h"
#include "llvm/ADT/SetVector.h"
#include "llvm/ADT/SmallVector.h"
#include "llvm/ADT/Statistic.h"
#include "llvm/Analysis/CFG.h"
#include "llvm/Analysis/ValueTracking.h"
#include "llvm/CodeGen/MachineBasicBlock.h"
#include "llvm/CodeGen/MachineBlockFrequencyInfo.h"
#include "llvm/CodeGen/MachineDominators.h"
#include "llvm/CodeGen/MachineFrameInfo.h"
#include "llvm/CodeGen/MachineFunction.h"
#include "llvm/CodeGen/MachineFunctionPass.h"
#include "llvm/CodeGen/MachineInstr.h"
#include "llvm/CodeGen/MachineLoopInfo.h"
#include "llvm/CodeGen/MachineOperand.h"
#include "llvm/CodeGen/MachineOptimizationRemarkEmitter.h"
#include "llvm/CodeGen/MachinePostDominators.h"
#include "llvm/CodeGen/RegisterClassInfo.h"
#include "llvm/CodeGen/RegisterScavenging.h"
#include "llvm/CodeGen/TargetFrameLowering.h"
#include "llvm/CodeGen/TargetInstrInfo.h"
#include "llvm/CodeGen/TargetLowering.h"
#include "llvm/CodeGen/TargetRegisterInfo.h"
#include "llvm/CodeGen/TargetSubtargetInfo.h"
#include "llvm/IR/Attributes.h"
#include "llvm/IR/Function.h"
#include "llvm/InitializePasses.h"
#include "llvm/MC/MCAsmInfo.h"
#include "llvm/Pass.h"
#include "llvm/Support/CommandLine.h"
#include "llvm/Support/Debug.h"
#include "llvm/Support/ErrorHandling.h"
#include "llvm/Support/raw_ostream.h"
#include "llvm/Target/TargetMachine.h"
#include <cassert>
#include <cstdint>
#include <memory>

Go to the source code of this file.

Macros

#define DEBUG_TYPE   "shrink-wrap"
 

Functions

 STATISTIC (NumFunc, "Number of functions")
 
 STATISTIC (NumCandidates, "Number of shrink-wrapping candidates")
 
 STATISTIC (NumCandidatesDropped, "Number of shrink-wrapping candidates dropped because of frequency")
 
template<typename ListOfBBs , typename DominanceAnalysis >
static MachineBasicBlockFindIDom (MachineBasicBlock &Block, ListOfBBs BBs, DominanceAnalysis &Dom, bool Strict=true)
 Helper function to find the immediate (post) dominator.
 
static bool isAnalyzableBB (const TargetInstrInfo &TII, MachineBasicBlock &Entry)
 
static bool hasDirtyPred (const DenseSet< const MachineBasicBlock * > &ReachableByDirty, const MachineBasicBlock &MBB)
 Determines if any predecessor of MBB is on the path from block that has use or def of CSRs/FI to MBB.
 
static void markAllReachable (DenseSet< const MachineBasicBlock * > &Visited, const MachineBasicBlock &MBB)
 Derives the list of all the basic blocks reachable from MBB.
 
static void collectBlocksReachableByDirty (const DenseSet< const MachineBasicBlock * > &DirtyBBs, DenseSet< const MachineBasicBlock * > &ReachableByDirty)
 Collect blocks reachable by use or def of CSRs/FI.
 
static bool isSaveReachableThroughClean (const MachineBasicBlock *SavePoint, ArrayRef< MachineBasicBlock * > CleanPreds)
 
static void updateTerminator (MachineBasicBlock *BBToUpdate, MachineBasicBlock *NMBB, const TargetInstrInfo *TII)
 This function updates the branches post restore point split.
 
static MachineBasicBlocktryToSplitRestore (MachineBasicBlock *MBB, ArrayRef< MachineBasicBlock * > DirtyPreds, const TargetInstrInfo *TII)
 This function splits the restore point and returns new restore point/BB.
 
static void rollbackRestoreSplit (MachineFunction &MF, MachineBasicBlock *NMBB, MachineBasicBlock *MBB, ArrayRef< MachineBasicBlock * > DirtyPreds, const TargetInstrInfo *TII)
 This function undoes the restore point split done earlier.
 
static bool giveUpWithRemarks (MachineOptimizationRemarkEmitter *ORE, StringRef RemarkName, StringRef RemarkMessage, const DiagnosticLocation &Loc, const MachineBasicBlock *MBB)
 

Variables

static cl::opt< cl::boolOrDefaultEnableShrinkWrapOpt ("enable-shrink-wrap", cl::Hidden, cl::desc("enable the shrink-wrapping pass"))
 
static cl::opt< boolEnablePostShrinkWrapOpt ("enable-shrink-wrap-region-split", cl::init(true), cl::Hidden, cl::desc("enable splitting of the restore block if possible"))
 

Macro Definition Documentation

◆ DEBUG_TYPE

#define DEBUG_TYPE   "shrink-wrap"

Definition at line 91 of file ShrinkWrap.cpp.

Function Documentation

◆ collectBlocksReachableByDirty()

static void collectBlocksReachableByDirty ( const DenseSet< const MachineBasicBlock * > &  DirtyBBs,
DenseSet< const MachineBasicBlock * > &  ReachableByDirty 
)
static

Collect blocks reachable by use or def of CSRs/FI.

Definition at line 424 of file ShrinkWrap.cpp.

References llvm::detail::DenseSetImpl< ValueT, MapTy, ValueInfoT >::count(), markAllReachable(), and MBB.

◆ FindIDom()

template<typename ListOfBBs , typename DominanceAnalysis >
static MachineBasicBlock * FindIDom ( MachineBasicBlock Block,
ListOfBBs  BBs,
DominanceAnalysis &  Dom,
bool  Strict = true 
)
static

Helper function to find the immediate (post) dominator.

Definition at line 375 of file ShrinkWrap.cpp.

References llvm::Block.

◆ giveUpWithRemarks()

static bool giveUpWithRemarks ( MachineOptimizationRemarkEmitter ORE,
StringRef  RemarkName,
StringRef  RemarkMessage,
const DiagnosticLocation Loc,
const MachineBasicBlock MBB 
)
static

◆ hasDirtyPred()

static bool hasDirtyPred ( const DenseSet< const MachineBasicBlock * > &  ReachableByDirty,
const MachineBasicBlock MBB 
)
static

Determines if any predecessor of MBB is on the path from block that has use or def of CSRs/FI to MBB.

ReachableByDirty: All blocks reachable from block that has use or def of CSR/FI.

Definition at line 401 of file ShrinkWrap.cpp.

References llvm::detail::DenseSetImpl< ValueT, MapTy, ValueInfoT >::count(), MBB, and llvm::MachineBasicBlock::predecessors().

◆ isAnalyzableBB()

static bool isAnalyzableBB ( const TargetInstrInfo TII,
MachineBasicBlock Entry 
)
static

Definition at line 388 of file ShrinkWrap.cpp.

References llvm::HexagonInstrInfo::analyzeBranch(), Cond, TBB, and TII.

◆ isSaveReachableThroughClean()

static bool isSaveReachableThroughClean ( const MachineBasicBlock SavePoint,
ArrayRef< MachineBasicBlock * >  CleanPreds 
)
static

◆ markAllReachable()

static void markAllReachable ( DenseSet< const MachineBasicBlock * > &  Visited,
const MachineBasicBlock MBB 
)
static

◆ rollbackRestoreSplit()

static void rollbackRestoreSplit ( MachineFunction MF,
MachineBasicBlock NMBB,
MachineBasicBlock MBB,
ArrayRef< MachineBasicBlock * >  DirtyPreds,
const TargetInstrInfo TII 
)
static

This function undoes the restore point split done earlier.

DirtyPreds: All predecessors of NMBB that are ReachableByDirty.

Restore point was split and the change needs to be unrolled. Make necessary changes to reset restore point from NMBB to MBB.

Definition at line 528 of file ShrinkWrap.cpp.

References llvm::MachineBasicBlock::begin(), llvm::MachineBasicBlock::end(), llvm::MachineBasicBlock::erase(), llvm::MachineBasicBlock::eraseFromParent(), llvm::SmallPtrSetImpl< PtrType >::insert(), MBB, llvm::MachineBasicBlock::removeSuccessor(), TII, and updateTerminator().

◆ STATISTIC() [1/3]

STATISTIC ( NumCandidates  ,
"Number of shrink-wrapping candidates"   
)

◆ STATISTIC() [2/3]

STATISTIC ( NumCandidatesDropped  ,
"Number of shrink-wrapping candidates dropped because of frequency"   
)

◆ STATISTIC() [3/3]

STATISTIC ( NumFunc  ,
"Number of functions"   
)

◆ tryToSplitRestore()

static MachineBasicBlock * tryToSplitRestore ( MachineBasicBlock MBB,
ArrayRef< MachineBasicBlock * >  DirtyPreds,
const TargetInstrInfo TII 
)
static

This function splits the restore point and returns new restore point/BB.

DirtyPreds: Predessors of MBB that are ReachableByDirty

Decision has been made to split the restore point. old restore point: MBB new restore point: NMBB This function makes the necessary block layout changes so that

  1. NMBB points to MBB unconditionally
  2. All dirtyPreds that previously pointed to MBB point to NMBB

Definition at line 485 of file ShrinkWrap.cpp.

References llvm::MachineBasicBlock::addLiveIn(), llvm::MachineBasicBlock::addSuccessor(), llvm::MachineFunction::CreateMachineBasicBlock(), llvm::MachineFunction::end(), llvm::MachineBasicBlock::getParent(), llvm::MachineFunction::insert(), llvm::SmallPtrSetImpl< PtrType >::insert(), llvm::MachineBasicBlock::liveins(), MBB, TII, and updateTerminator().

◆ updateTerminator()

static void updateTerminator ( MachineBasicBlock BBToUpdate,
MachineBasicBlock NMBB,
const TargetInstrInfo TII 
)
static

This function updates the branches post restore point split.

Restore point has been split. Old restore point: MBB New restore point: NMBB Any basic block(say BBToUpdate) which had a fallthrough to MBB previously should

  1. Fallthrough to NMBB iff NMBB is inserted immediately above MBB in the block layout OR
  2. Branch unconditionally to NMBB iff NMBB is inserted at any other place.

Definition at line 464 of file ShrinkWrap.cpp.

References DL, llvm::MachineBasicBlock::findBranchDebugLoc(), llvm::MachineBasicBlock::isLayoutSuccessor(), and TII.

Referenced by rollbackRestoreSplit(), and tryToSplitRestore().

Variable Documentation

◆ EnablePostShrinkWrapOpt

cl::opt< bool > EnablePostShrinkWrapOpt("enable-shrink-wrap-region-split", cl::init(true), cl::Hidden, cl::desc("enable splitting of the restore block if possible")) ( "enable-shrink-wrap-region-split"  ,
cl::init(true ,
cl::Hidden  ,
cl::desc("enable splitting of the restore block if possible")   
)
static

◆ EnableShrinkWrapOpt

cl::opt< cl::boolOrDefault > EnableShrinkWrapOpt("enable-shrink-wrap", cl::Hidden, cl::desc("enable the shrink-wrapping pass")) ( "enable-shrink-wrap"  ,
cl::Hidden  ,
cl::desc("enable the shrink-wrapping pass")   
)
static