PlaceSafepoints.cpp File Reference

#include "llvm/Transforms/Scalar/PlaceSafepoints.h"
#include "llvm/InitializePasses.h"
#include "llvm/Pass.h"
#include "llvm/ADT/SetVector.h"
#include "llvm/ADT/Statistic.h"
#include "llvm/Analysis/CFG.h"
#include "llvm/Analysis/LoopInfo.h"
#include "llvm/Analysis/ScalarEvolution.h"
#include "llvm/Analysis/TargetLibraryInfo.h"
#include "llvm/IR/Dominators.h"
#include "llvm/IR/IntrinsicInst.h"
#include "llvm/IR/LegacyPassManager.h"
#include "llvm/IR/Module.h"
#include "llvm/IR/Statepoint.h"
#include "llvm/Support/CommandLine.h"
#include "llvm/Support/Debug.h"
#include "llvm/Transforms/Scalar.h"
#include "llvm/Transforms/Utils/BasicBlockUtils.h"
#include "llvm/Transforms/Utils/Cloning.h"
#include "llvm/Transforms/Utils/Local.h"

Go to the source code of this file.

Macros
#define	DEBUG_TYPE   "place-safepoints"

Functions
	STATISTIC (NumEntrySafepoints, "Number of entry safepoints inserted")
	STATISTIC (NumBackedgeSafepoints, "Number of backedge safepoints inserted")
	STATISTIC (CallInLoop, "Number of loops without safepoints due to calls in loop")
	STATISTIC (FiniteExecution, "Number of loops without safepoints finite execution")
	INITIALIZE_PASS_BEGIN (PlaceBackedgeSafepointsLegacyPass, "place-backedge-safepoints-impl", "Place Backedge Safepoints", false, false) INITIALIZE_PASS_END(PlaceBackedgeSafepointsLegacyPass
place backedge safepoints Place Backedge static false bool	containsUnconditionalCallSafepoint (Loop *L, BasicBlock *Header, BasicBlock *Pred, DominatorTree &DT, const TargetLibraryInfo &TLI)
	Returns true if this loop is known to contain a call safepoint which must unconditionally execute on any iteration of the loop which returns to the loop header via an edge from Pred.
static bool	mustBeFiniteCountedLoop (Loop *L, ScalarEvolution *SE, BasicBlock *Pred)
	Returns true if this loop is known to terminate in a finite number of iterations.
static Instruction *	findLocationForEntrySafepoint (Function &F, DominatorTree &DT)
static bool	isGCSafepointPoll (Function &F)
static bool	shouldRewriteFunction (Function &F)
	Returns true if this function should be rewritten to include safepoint polls and parseable call sites.
static bool	enableEntrySafepoints (Function &F)
static bool	enableBackedgeSafepoints (Function &F)
static bool	enableCallSafepoints (Function &F)
static void	InsertSafepointPoll (BasicBlock::iterator InsertBefore, std::vector< CallBase * > &ParsePointsNeeded, const TargetLibraryInfo &TLI)
static bool	needsStatepoint (CallBase *Call, const TargetLibraryInfo &TLI)
static void	scanOneBB (Instruction *Start, Instruction *End, std::vector< CallInst * > &Calls, DenseSet< BasicBlock * > &Seen, std::vector< BasicBlock * > &Worklist)
static void	scanInlinedCode (Instruction *Start, Instruction *End, std::vector< CallInst * > &Calls, DenseSet< BasicBlock * > &Seen)
static bool	doesNotRequireEntrySafepointBefore (CallBase *Call)
	Returns true if an entry safepoint is not required before this callsite in the caller function.

Variables
static cl::opt< bool >	AllBackedges ("spp-all-backedges", cl::Hidden, cl::init(false))
static cl::opt< int >	CountedLoopTripWidth ("spp-counted-loop-trip-width", cl::Hidden, cl::init(32))
	How narrow does the trip count of a loop have to be to have to be considered "counted"? Counted loops do not get safepoints at backedges.
static cl::opt< bool >	SplitBackedge ("spp-split-backedge", cl::Hidden, cl::init(false))
static cl::opt< bool >	NoEntry ("spp-no-entry", cl::Hidden, cl::init(false))
static cl::opt< bool >	NoCall ("spp-no-call", cl::Hidden, cl::init(false))
static cl::opt< bool >	NoBackedge ("spp-no-backedge", cl::Hidden, cl::init(false))
place backedge safepoints	impl
place backedge safepoints Place Backedge	Safepoints
place backedge safepoints Place Backedge	false
const char	GCSafepointPollName [] = "gc.safepoint_poll"

Macro Definition Documentation

DEBUG_TYPE

#define DEBUG_TYPE   "place-safepoints"

Definition at line 74 of file PlaceSafepoints.cpp.

Function Documentation

containsUnconditionalCallSafepoint()

static bool containsUnconditionalCallSafepoint ( Loop *  L, BasicBlock *  Header, BasicBlock *  Pred, DominatorTree &  DT, const TargetLibraryInfo &  TLI  )

static

Returns true if this loop is known to contain a call safepoint which must unconditionally execute on any iteration of the loop which returns to the loop header via an edge from Pred.

Returns a conservative correct answer; i.e. false is always valid.

Definition at line 403 of file PlaceSafepoints.cpp.

References assert(), llvm::DominatorTree::dominates(), llvm::DomTreeNodeBase< NodeT >::getBlock(), llvm::DomTreeNodeBase< NodeT >::getIDom(), llvm::DominatorTreeBase< NodeT, IsPostDom >::getNode(), I, and needsStatepoint().

doesNotRequireEntrySafepointBefore()

static bool doesNotRequireEntrySafepointBefore ( CallBase *  Call )

static

Returns true if an entry safepoint is not required before this callsite in the caller function.

Definition at line 513 of file PlaceSafepoints.cpp.

References II.

Referenced by findLocationForEntrySafepoint().

enableBackedgeSafepoints()

static bool enableBackedgeSafepoints ( Function &  F )

static

Definition at line 613 of file PlaceSafepoints.cpp.

References NoBackedge.

Referenced by llvm::PlaceSafepointsPass::runImpl().

enableCallSafepoints()

static bool enableCallSafepoints ( Function &  F )

static

Definition at line 614 of file PlaceSafepoints.cpp.

References NoCall.

Referenced by llvm::PlaceSafepointsPass::runImpl().

enableEntrySafepoints()

static bool enableEntrySafepoints ( Function &  F )

static

Definition at line 612 of file PlaceSafepoints.cpp.

References NoEntry.

Referenced by llvm::PlaceSafepointsPass::runImpl().

findLocationForEntrySafepoint()

static Instruction * findLocationForEntrySafepoint ( Function &  F, DominatorTree &  DT  )

static

Definition at line 536 of file PlaceSafepoints.cpp.

References assert(), doesNotRequireEntrySafepointBefore(), F, llvm::BasicBlock::getUniquePredecessor(), I, and llvm::Instruction::isTerminator().

Referenced by llvm::PlaceSafepointsPass::runImpl().

INITIALIZE_PASS_BEGIN()

INITIALIZE_PASS_BEGIN	(	PlaceBackedgeSafepointsLegacyPass	,
		"place-backedge-safepoints-impl"	,
		"Place Backedge Safepoints"	,
		false	,
		false
	)

InsertSafepointPoll()

static void InsertSafepointPoll ( BasicBlock::iterator  InsertBefore, std::vector< CallBase * > &  ParsePointsNeeded, const TargetLibraryInfo &  TLI  )

static

Definition at line 620 of file PlaceSafepoints.cpp.

References After, assert(), Before, llvm::BasicBlock::begin(), llvm::CallInst::Create(), llvm::BasicBlock::end(), F, GCSafepointPollName, llvm::FunctionType::get(), llvm::BasicBlock::getParent(), llvm::Type::getVoidTy(), llvm::InlineFunction(), llvm::isPotentiallyReachable(), llvm::InlineResult::isSuccess(), needsStatepoint(), scanInlinedCode(), and llvm::InlineFunctionInfo::StaticAllocas.

Referenced by llvm::PlaceSafepointsPass::runImpl().

isGCSafepointPoll()

static bool isGCSafepointPoll ( Function &  F )

static

Definition at line 591 of file PlaceSafepoints.cpp.

References F, and GCSafepointPollName.

Referenced by llvm::PlaceSafepointsPass::runImpl().

mustBeFiniteCountedLoop()

static bool mustBeFiniteCountedLoop ( Loop *  L, ScalarEvolution *  SE, BasicBlock *  Pred  )

static

Returns true if this loop is known to terminate in a finite number of iterations.

Note that this function may return false for a loop which does actual terminate in a finite constant number of iterations due to conservatism in the analysis.

Definition at line 445 of file PlaceSafepoints.cpp.

References CountedLoopTripWidth, llvm::ScalarEvolution::getConstantMaxBackedgeTakenCount(), llvm::ScalarEvolution::getExitCount(), llvm::ConstantRange::getUnsignedMax(), llvm::ScalarEvolution::getUnsignedRange(), and llvm::APInt::isIntN().

needsStatepoint()

static bool needsStatepoint ( CallBase *  Call, const TargetLibraryInfo &  TLI  )

static

Definition at line 387 of file PlaceSafepoints.cpp.

References llvm::callsGCLeafFunction().

Referenced by containsUnconditionalCallSafepoint(), and InsertSafepointPoll().

scanInlinedCode()

static void scanInlinedCode ( Instruction *  Start, Instruction *  End, std::vector< CallInst * > &  Calls, DenseSet< BasicBlock * > &  Seen  )

static

Definition at line 497 of file PlaceSafepoints.cpp.

References llvm::BasicBlock::back(), llvm::BasicBlock::begin(), End, llvm::detail::DenseSetImpl< ValueT, MapTy, ValueInfoT >::insert(), and scanOneBB().

Referenced by InsertSafepointPoll().

scanOneBB()

static void scanOneBB ( Instruction *  Start, Instruction *  End, std::vector< CallInst * > &  Calls, DenseSet< BasicBlock * > &  Seen, std::vector< BasicBlock * > &  Worklist  )

static

Definition at line 470 of file PlaceSafepoints.cpp.

References assert(), End, llvm::BasicBlock::getParent(), llvm::detail::DenseSetImpl< ValueT, MapTy, ValueInfoT >::insert(), and llvm::successors().

Referenced by scanInlinedCode().

shouldRewriteFunction()

static bool shouldRewriteFunction ( Function &  F )

static

Returns true if this function should be rewritten to include safepoint polls and parseable call sites.

The main point of this function is to be an extension point for custom logic.

Definition at line 598 of file PlaceSafepoints.cpp.

References F.

Referenced by llvm::PlaceSafepointsPass::runImpl().

STATISTIC() [1/4]

STATISTIC	(	CallInLoop	,
		"Number of loops without safepoints due to calls in loop"
	)

STATISTIC() [2/4]

STATISTIC	(	FiniteExecution	,
		"Number of loops without safepoints finite execution"
	)

STATISTIC() [3/4]

STATISTIC	(	NumBackedgeSafepoints	,
		"Number of backedge safepoints inserted"
	)

STATISTIC() [4/4]

STATISTIC	(	NumEntrySafepoints	,
		"Number of entry safepoints inserted"
	)

Variable Documentation

AllBackedges

cl::opt< bool > AllBackedges("spp-all-backedges", cl::Hidden, cl::init(false)) ( "spp-all-backedges"  , cl::Hidden  , cl::init(false)    )

static

CountedLoopTripWidth

cl::opt< int > CountedLoopTripWidth("spp-counted-loop-trip-width", cl::Hidden, cl::init(32)) ( "spp-counted-loop-trip-width"  , cl::Hidden  , cl::init(32)    )

static

How narrow does the trip count of a loop have to be to have to be considered "counted"? Counted loops do not get safepoints at backedges.

Referenced by mustBeFiniteCountedLoop().

false

place backedge safepoints Place Backedge false

Definition at line 174 of file PlaceSafepoints.cpp.

GCSafepointPollName

const char GCSafepointPollName[] = "gc.safepoint_poll"

Definition at line 589 of file PlaceSafepoints.cpp.

Referenced by InsertSafepointPoll(), and isGCSafepointPoll().

impl

place backedge safepoints impl

Definition at line 173 of file PlaceSafepoints.cpp.

Referenced by llvm::RuntimeDyldMachOCRTPBase< Impl >::finalizeLoad(), llvm::sys::SmartMutex< mt_only >::lock(), llvm::sys::SmartRWMutex< mt_only >::lock(), llvm::sys::SmartRWMutex< mt_only >::lock_shared(), llvm::sys::SmartMutex< mt_only >::try_lock(), llvm::sys::SmartRWMutex< mt_only >::try_lock(), llvm::sys::SmartRWMutex< mt_only >::try_lock_shared(), llvm::sys::SmartMutex< mt_only >::unlock(), llvm::sys::SmartRWMutex< mt_only >::unlock(), and llvm::sys::SmartRWMutex< mt_only >::unlock_shared().

NoBackedge

cl::opt< bool > NoBackedge("spp-no-backedge", cl::Hidden, cl::init(false)) ( "spp-no-backedge"  , cl::Hidden  , cl::init(false)    )

static

Referenced by enableBackedgeSafepoints().

NoCall

cl::opt< bool > NoCall("spp-no-call", cl::Hidden, cl::init(false)) ( "spp-no-call"  , cl::Hidden  , cl::init(false)    )

static

Referenced by enableCallSafepoints().

NoEntry

cl::opt< bool > NoEntry("spp-no-entry", cl::Hidden, cl::init(false)) ( "spp-no-entry"  , cl::Hidden  , cl::init(false)    )

static

Referenced by enableEntrySafepoints().

Safepoints

place backedge safepoints Place Backedge Safepoints

Definition at line 174 of file PlaceSafepoints.cpp.

SplitBackedge

cl::opt< bool > SplitBackedge("spp-split-backedge", cl::Hidden, cl::init(false)) ( "spp-split-backedge"  , cl::Hidden  , cl::init(false)    )

static

Referenced by llvm::PlaceSafepointsPass::runImpl().