#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/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"

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 (Instruction 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 73 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 405 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 515 of file PlaceSafepoints.cpp.

Referenced by findLocationForEntrySafepoint().

◆ enableBackedgeSafepoints()

static bool enableBackedgeSafepoints ( Function & F )

static

Definition at line 615 of file PlaceSafepoints.cpp.

References NoBackedge.

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

◆ enableCallSafepoints()

static bool enableCallSafepoints ( Function & F )

static

Definition at line 616 of file PlaceSafepoints.cpp.

References NoCall.

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

◆ enableEntrySafepoints()

static bool enableEntrySafepoints ( Function & F )

static

Definition at line 614 of file PlaceSafepoints.cpp.

References NoEntry.

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

◆ findLocationForEntrySafepoint()

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

static

Definition at line 538 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	(	Instruction *	InsertBefore,
		std::vector< CallBase * > &	ParsePointsNeeded,
		const TargetLibraryInfo &	TLI
	)

static

Definition at line 622 of file PlaceSafepoints.cpp.

References assert(), llvm::BasicBlock::begin(), llvm::CallInst::Create(), llvm::BasicBlock::end(), F, GCSafepointPollName, llvm::FunctionType::get(), llvm::Instruction::getModule(), llvm::Instruction::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 593 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 447 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 389 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 499 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 472 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 600 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 173 of file PlaceSafepoints.cpp.

◆ GCSafepointPollName

const char GCSafepointPollName[] = "gc.safepoint_poll"

Definition at line 591 of file PlaceSafepoints.cpp.

Referenced by InsertSafepointPoll(), and isGCSafepointPoll().

◆ impl

place backedge safepoints impl

Definition at line 172 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::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 173 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().

Macros

Functions

Variables

Macro Definition Documentation

◆ DEBUG_TYPE

Function Documentation

◆ containsUnconditionalCallSafepoint()

◆ doesNotRequireEntrySafepointBefore()

◆ enableBackedgeSafepoints()

◆ enableCallSafepoints()

◆ enableEntrySafepoints()

◆ findLocationForEntrySafepoint()

◆ INITIALIZE_PASS_BEGIN()

◆ InsertSafepointPoll()

◆ isGCSafepointPoll()

◆ mustBeFiniteCountedLoop()

◆ needsStatepoint()

◆ scanInlinedCode()

◆ scanOneBB()

◆ shouldRewriteFunction()

◆ STATISTIC() [1/4]

◆ STATISTIC() [2/4]

◆ STATISTIC() [3/4]

◆ STATISTIC() [4/4]

Variable Documentation

◆ AllBackedges

◆ CountedLoopTripWidth

◆ false

◆ GCSafepointPollName

◆ impl

◆ NoBackedge

◆ NoCall

◆ NoEntry

◆ Safepoints

◆ SplitBackedge