RewriteStatepointsForGC.cpp File Reference

#include "llvm/Transforms/Scalar/RewriteStatepointsForGC.h"
#include "llvm/ADT/ArrayRef.h"
#include "llvm/ADT/DenseMap.h"
#include "llvm/ADT/DenseSet.h"
#include "llvm/ADT/MapVector.h"
#include "llvm/ADT/STLExtras.h"
#include "llvm/ADT/Sequence.h"
#include "llvm/ADT/SetVector.h"
#include "llvm/ADT/SmallVector.h"
#include "llvm/ADT/StringRef.h"
#include "llvm/ADT/iterator_range.h"
#include "llvm/Analysis/DomTreeUpdater.h"
#include "llvm/Analysis/TargetLibraryInfo.h"
#include "llvm/Analysis/TargetTransformInfo.h"
#include "llvm/IR/Argument.h"
#include "llvm/IR/AttributeMask.h"
#include "llvm/IR/Attributes.h"
#include "llvm/IR/BasicBlock.h"
#include "llvm/IR/CallingConv.h"
#include "llvm/IR/Constant.h"
#include "llvm/IR/Constants.h"
#include "llvm/IR/DataLayout.h"
#include "llvm/IR/DerivedTypes.h"
#include "llvm/IR/Dominators.h"
#include "llvm/IR/Function.h"
#include "llvm/IR/GCStrategy.h"
#include "llvm/IR/IRBuilder.h"
#include "llvm/IR/InstIterator.h"
#include "llvm/IR/InstrTypes.h"
#include "llvm/IR/Instruction.h"
#include "llvm/IR/Instructions.h"
#include "llvm/IR/IntrinsicInst.h"
#include "llvm/IR/Intrinsics.h"
#include "llvm/IR/LLVMContext.h"
#include "llvm/IR/MDBuilder.h"
#include "llvm/IR/Metadata.h"
#include "llvm/IR/Module.h"
#include "llvm/IR/Statepoint.h"
#include "llvm/IR/Type.h"
#include "llvm/IR/User.h"
#include "llvm/IR/Value.h"
#include "llvm/IR/ValueHandle.h"
#include "llvm/Support/Casting.h"
#include "llvm/Support/CommandLine.h"
#include "llvm/Support/Compiler.h"
#include "llvm/Support/Debug.h"
#include "llvm/Support/ErrorHandling.h"
#include "llvm/Support/raw_ostream.h"
#include "llvm/Transforms/Utils/BasicBlockUtils.h"
#include "llvm/Transforms/Utils/Local.h"
#include "llvm/Transforms/Utils/PromoteMemToReg.h"
#include <cassert>
#include <cstddef>
#include <cstdint>
#include <iterator>
#include <optional>
#include <set>
#include <string>
#include <utility>
#include <vector>

Go to the source code of this file.

Macros
#define	DEBUG_TYPE   "rewrite-statepoints-for-gc"

Functions
static void	stripNonValidData (Module &M)
	The IR fed into RewriteStatepointsForGC may have had attributes and metadata implying dereferenceability that are no longer valid/correct after RewriteStatepointsForGC has run.
static std::unique_ptr< GCStrategy >	findGCStrategy (Function &F)
	Looks up the GC strategy for a given function, returning null if the function doesn't have a GC tag.
static bool	shouldRewriteStatepointsIn (Function &F)
	Returns true if this function should be rewritten by this pass.
static ArrayRef< Use >	GetDeoptBundleOperands (const CallBase *Call)
static void	computeLiveInValues (DominatorTree &DT, Function &F, GCPtrLivenessData &Data, GCStrategy *GC)
	Compute the live-in set for every basic block in the function.
static void	findLiveSetAtInst (Instruction *inst, GCPtrLivenessData &Data, StatepointLiveSetTy &out, GCStrategy *GC)
	Given results from the dataflow liveness computation, find the set of live Values at a particular instruction.
static bool	isGCPointerType (Type *T, GCStrategy *GC)
static bool	isHandledGCPointerType (Type *T, GCStrategy *GC)
static bool	containsGCPtrType (Type *Ty, GCStrategy *GC)
	Returns true if this type contains a gc pointer whether we know how to handle that type or not.
static bool	isUnhandledGCPointerType (Type *Ty, GCStrategy *GC)
static std::string	suffixed_name_or (Value *V, StringRef Suffix, StringRef DefaultName)
static void	analyzeParsePointLiveness (DominatorTree &DT, GCPtrLivenessData &OriginalLivenessData, CallBase *Call, PartiallyConstructedSafepointRecord &Result, GCStrategy *GC)
static bool	isKnownBase (Value *V, const IsKnownBaseMapTy &KnownBases)
	Returns true if V is a known base.
static void	setKnownBase (Value *V, bool IsKnownBase, IsKnownBaseMapTy &KnownBases)
	Caches the IsKnownBase flag for a value and asserts that it wasn't present in the cache before.
static Value *	findBaseDefiningValue (Value *I, DefiningValueMapTy &Cache, IsKnownBaseMapTy &KnownBases)
	Helper function for findBasePointer - Will return a value which either a) defines the base pointer for the input, b) blocks the simple search (i.e.
static Value *	findBaseDefiningValueOfVector (Value *I, DefiningValueMapTy &Cache, IsKnownBaseMapTy &KnownBases)
	Return a base defining value for the 'Index' element of the given vector instruction 'I'.
static Value *	findBaseDefiningValueCached (Value *I, DefiningValueMapTy &Cache, IsKnownBaseMapTy &KnownBases)
	Returns the base defining value for this value.
static Value *	findBaseOrBDV (Value *I, DefiningValueMapTy &Cache, IsKnownBaseMapTy &KnownBases)
	Return a base pointer for this value if known.
static bool	isOriginalBaseResult (Value *V)
	This value is a base pointer that is not generated by RS4GC, i.e.
static bool	areBothVectorOrScalar (Value *First, Value *Second)
static raw_ostream &	operator<< (raw_ostream &OS, const BDVState &State)
static Value *	findBasePointer (Value *I, DefiningValueMapTy &Cache, IsKnownBaseMapTy &KnownBases)
	For a given value or instruction, figure out what base ptr its derived from.
static void	findBasePointers (const StatepointLiveSetTy &live, PointerToBaseTy &PointerToBase, DominatorTree *DT, DefiningValueMapTy &DVCache, IsKnownBaseMapTy &KnownBases)
static void	findBasePointers (DominatorTree &DT, DefiningValueMapTy &DVCache, CallBase *Call, PartiallyConstructedSafepointRecord &result, PointerToBaseTy &PointerToBase, IsKnownBaseMapTy &KnownBases)
	Find the required based pointers (and adjust the live set) for the given parse point.
static void	recomputeLiveInValues (GCPtrLivenessData &RevisedLivenessData, CallBase *Call, PartiallyConstructedSafepointRecord &result, PointerToBaseTy &PointerToBase, GCStrategy *GC)
	Given an updated version of the dataflow liveness results, update the liveset and base pointer maps for the call site CS.
static void	recomputeLiveInValues (Function &F, DominatorTree &DT, ArrayRef< CallBase * > toUpdate, MutableArrayRef< struct PartiallyConstructedSafepointRecord > records, PointerToBaseTy &PointerToBase, GCStrategy *GC)
static Instruction *	rematerializeChain (ArrayRef< Instruction * > ChainToBase, BasicBlock::iterator InsertBefore, Value *RootOfChain, Value *AlternateLiveBase)
static BasicBlock *	normalizeForInvokeSafepoint (BasicBlock *BB, BasicBlock *InvokeParent, DominatorTree &DT)
static AttributeList	legalizeCallAttributes (CallBase *Call, bool IsMemIntrinsic, AttributeList StatepointAL)
static void	CreateGCRelocates (ArrayRef< Value * > LiveVariables, ArrayRef< Value * > BasePtrs, Instruction *StatepointToken, IRBuilder<> &Builder, GCStrategy *GC)
	Helper function to place all gc relocates necessary for the given statepoint.
static StringRef	getDeoptLowering (CallBase *Call)
static void	makeStatepointExplicitImpl (CallBase *Call, const SmallVectorImpl< Value * > &BasePtrs, const SmallVectorImpl< Value * > &LiveVariables, PartiallyConstructedSafepointRecord &Result, std::vector< DeferredReplacement > &Replacements, const PointerToBaseTy &PointerToBase, GCStrategy *GC)
static void	makeStatepointExplicit (DominatorTree &DT, CallBase *Call, PartiallyConstructedSafepointRecord &Result, std::vector< DeferredReplacement > &Replacements, const PointerToBaseTy &PointerToBase, GCStrategy *GC)
static void	insertRelocationStores (iterator_range< Value::user_iterator > GCRelocs, DenseMap< Value *, AllocaInst * > &AllocaMap, DenseSet< Value * > &VisitedLiveValues)
static void	insertRematerializationStores (const RematerializedValueMapTy &RematerializedValues, DenseMap< Value *, AllocaInst * > &AllocaMap, DenseSet< Value * > &VisitedLiveValues)
static void	relocationViaAlloca (Function &F, DominatorTree &DT, ArrayRef< Value * > Live, ArrayRef< PartiallyConstructedSafepointRecord > Records)
	Do all the relocation update via allocas and mem2reg.
static void	insertUseHolderAfter (CallBase *Call, const ArrayRef< Value * > Values, SmallVectorImpl< CallInst * > &Holders)
	Insert holders so that each Value is obviously live through the entire lifetime of the call.
static void	findLiveReferences (Function &F, DominatorTree &DT, ArrayRef< CallBase * > toUpdate, MutableArrayRef< struct PartiallyConstructedSafepointRecord > records, GCStrategy *GC)
static Value *	findRematerializableChainToBasePointer (SmallVectorImpl< Instruction * > &ChainToBase, Value *CurrentValue)
static InstructionCost	chainToBasePointerCost (SmallVectorImpl< Instruction * > &Chain, TargetTransformInfo &TTI)
static bool	AreEquivalentPhiNodes (PHINode &OrigRootPhi, PHINode &AlternateRootPhi)
static void	findRematerializationCandidates (PointerToBaseTy PointerToBase, RematCandTy &RematerizationCandidates, TargetTransformInfo &TTI)
static void	rematerializeLiveValuesAtUses (RematCandTy &RematerizationCandidates, MutableArrayRef< PartiallyConstructedSafepointRecord > Records, PointerToBaseTy &PointerToBase)
static void	rematerializeLiveValues (CallBase *Call, PartiallyConstructedSafepointRecord &Info, PointerToBaseTy &PointerToBase, RematCandTy &RematerizationCandidates, TargetTransformInfo &TTI)
static bool	inlineGetBaseAndOffset (Function &F, SmallVectorImpl< CallInst * > &Intrinsics, DefiningValueMapTy &DVCache, IsKnownBaseMapTy &KnownBases)
static bool	insertParsePoints (Function &F, DominatorTree &DT, TargetTransformInfo &TTI, SmallVectorImpl< CallBase * > &ToUpdate, DefiningValueMapTy &DVCache, IsKnownBaseMapTy &KnownBases)
static AttributeMask	getParamAndReturnAttributesToRemove ()
static void	stripNonValidAttributesFromPrototype (Function &F)
static void	stripInvalidMetadataFromInstruction (Instruction &I)
	Certain metadata on instructions are invalid after running RS4GC.
static void	stripNonValidDataFromBody (Function &F)
static void	computeLiveInValues (BasicBlock::reverse_iterator Begin, BasicBlock::reverse_iterator End, SetVector< Value * > &LiveTmp, GCStrategy *GC)
	Compute the live-in set for the location rbegin starting from the live-out set of the basic block.
static void	computeLiveOutSeed (BasicBlock *BB, SetVector< Value * > &LiveTmp, GCStrategy *GC)
static SetVector< Value * >	computeKillSet (BasicBlock *BB, GCStrategy *GC)
static void	checkBasicSSA (DominatorTree &DT, SetVector< Value * > &Live, Instruction *TI, bool TermOkay=false)
	Check that the items in 'Live' dominate 'TI'.
static void	checkBasicSSA (DominatorTree &DT, GCPtrLivenessData &Data, BasicBlock &BB)
	Check that all the liveness sets used during the computation of liveness obey basic SSA properties.

Variables
static cl::opt< bool >	PrintLiveSet ("spp-print-liveset", cl::Hidden, cl::init(false))
static cl::opt< bool >	PrintLiveSetSize ("spp-print-liveset-size", cl::Hidden, cl::init(false))
static cl::opt< bool >	PrintBasePointers ("spp-print-base-pointers", cl::Hidden, cl::init(false))
static cl::opt< unsigned >	RematerializationThreshold ("spp-rematerialization-threshold", cl::Hidden, cl::init(6))
static bool	ClobberNonLive = false
static cl::opt< bool, true >	ClobberNonLiveOverride ("rs4gc-clobber-non-live", cl::location(ClobberNonLive), cl::Hidden)
static cl::opt< bool >	AllowStatepointWithNoDeoptInfo ("rs4gc-allow-statepoint-with-no-deopt-info", cl::Hidden, cl::init(true))
static cl::opt< bool >	RematDerivedAtUses ("rs4gc-remat-derived-at-uses", cl::Hidden, cl::init(true))
static constexpr Attribute::AttrKind	FnAttrsToStrip []

Macro Definition Documentation

DEBUG_TYPE

#define DEBUG_TYPE   "rewrite-statepoints-for-gc"

Definition at line 76 of file RewriteStatepointsForGC.cpp.

Function Documentation

analyzeParsePointLiveness()

static void analyzeParsePointLiveness ( DominatorTree &  DT, GCPtrLivenessData &  OriginalLivenessData, CallBase *  Call, PartiallyConstructedSafepointRecord &  Result, GCStrategy *  GC  )

static

Definition at line 313 of file RewriteStatepointsForGC.cpp.

References llvm::dbgs(), findLiveSetAtInst(), PrintLiveSet, and PrintLiveSetSize.

Referenced by findLiveReferences().

areBothVectorOrScalar()

static bool areBothVectorOrScalar ( Value *  First, Value *  Second  )

static

Definition at line 687 of file RewriteStatepointsForGC.cpp.

References llvm::First, and llvm::Value::getType().

Referenced by findBasePointer().

AreEquivalentPhiNodes()

static bool AreEquivalentPhiNodes ( PHINode &  OrigRootPhi, PHINode &  AlternateRootPhi  )

static

Definition at line 2321 of file RewriteStatepointsForGC.cpp.

References llvm::DenseMapBase< DerivedT, KeyT, ValueT, KeyInfoT, BucketT >::end(), llvm::DenseMapBase< DerivedT, KeyT, ValueT, KeyInfoT, BucketT >::find(), llvm::PHINode::getIncomingBlock(), llvm::PHINode::getIncomingValue(), llvm::PHINode::getNumIncomingValues(), and llvm::ilist_detail::node_parent_access< NodeTy, ParentTy >::getParent().

Referenced by findRematerializationCandidates().

chainToBasePointerCost()

static InstructionCost chainToBasePointerCost ( SmallVectorImpl< Instruction * > &  Chain, TargetTransformInfo &  TTI  )

static

Definition at line 2287 of file RewriteStatepointsForGC.cpp.

References assert(), GEP, llvm::TargetTransformInfo::getAddressComputationCost(), llvm::TargetTransformInfo::getCastContextHint(), llvm::TargetTransformInfo::getCastInstrCost(), llvm_unreachable, and llvm::TargetTransformInfo::TCK_SizeAndLatency.

Referenced by findRematerializationCandidates().

checkBasicSSA() [1/2]

static void checkBasicSSA ( DominatorTree &  DT, GCPtrLivenessData &  Data, BasicBlock &  BB  )

static

Check that all the liveness sets used during the computation of liveness obey basic SSA properties.

This is useful for finding cases where we miss a def.

Definition at line 3269 of file RewriteStatepointsForGC.cpp.

References checkBasicSSA(), llvm::Data, and llvm::BasicBlock::getTerminator().

checkBasicSSA() [2/2]

static void checkBasicSSA ( DominatorTree &  DT, SetVector< Value * > &  Live, Instruction *  TI, bool  TermOkay = false  )

static

Check that the items in 'Live' dominate 'TI'.

This is used as a basic validation check for the liveness computation.

Definition at line 3251 of file RewriteStatepointsForGC.cpp.

References assert(), llvm::DominatorTree::dominates(), I, and Live.

Referenced by checkBasicSSA(), and computeLiveInValues().

computeKillSet()

static SetVector< Value * > computeKillSet ( BasicBlock *  BB, GCStrategy *  GC  )

static

Definition at line 3240 of file RewriteStatepointsForGC.cpp.

References I, llvm::SetVector< T, Vector, Set, N >::insert(), and isHandledGCPointerType().

Referenced by computeLiveInValues().

computeLiveInValues() [1/2]

static void computeLiveInValues ( BasicBlock::reverse_iterator  Begin, BasicBlock::reverse_iterator  End, SetVector< Value * > &  LiveTmp, GCStrategy *  GC  )

static

Compute the live-in set for the location rbegin starting from the live-out set of the basic block.

Definition at line 3190 of file RewriteStatepointsForGC.cpp.

References assert(), End, I, llvm::SetVector< T, Vector, Set, N >::insert(), isHandledGCPointerType(), isUnhandledGCPointerType(), llvm::make_range(), and llvm::SetVector< T, Vector, Set, N >::remove().

computeLiveInValues() [2/2]

static void computeLiveInValues ( DominatorTree &  DT, Function &  F, GCPtrLivenessData &  Data, GCStrategy *  GC  )

static

Compute the live-in set for every basic block in the function.

Definition at line 3277 of file RewriteStatepointsForGC.cpp.

References assert(), checkBasicSSA(), computeKillSet(), computeLiveInValues(), computeLiveOutSeed(), llvm::Data, llvm::SetVector< T, Vector, Set, N >::empty(), F, llvm::SetVector< T, Vector, Set, N >::insert_range(), llvm::SetVector< T, Vector, Set, N >::pop_back_val(), llvm::predecessors(), llvm::SetVector< T, Vector, Set, N >::set_subtract(), llvm::SetVector< T, Vector, Set, N >::set_union(), llvm::SetVector< T, Vector, Set, N >::size(), and llvm::successors().

Referenced by computeLiveInValues(), findLiveReferences(), findLiveSetAtInst(), and recomputeLiveInValues().

computeLiveOutSeed()

static void computeLiveOutSeed ( BasicBlock *  BB, SetVector< Value * > &  LiveTmp, GCStrategy *  GC  )

static

Definition at line 3223 of file RewriteStatepointsForGC.cpp.

References assert(), llvm::PHINode::getIncomingValueForBlock(), I, llvm::SetVector< T, Vector, Set, N >::insert(), isHandledGCPointerType(), isUnhandledGCPointerType(), and llvm::successors().

Referenced by computeLiveInValues().

containsGCPtrType()

static bool containsGCPtrType ( Type *  Ty, GCStrategy *  GC  )

static

Returns true if this type contains a gc pointer whether we know how to handle that type or not.

Definition at line 281 of file RewriteStatepointsForGC.cpp.

References llvm::any_of(), containsGCPtrType(), and isGCPointerType().

CreateGCRelocates()

static void CreateGCRelocates ( ArrayRef< Value * >  LiveVariables, ArrayRef< Value * >  BasePtrs, Instruction *  StatepointToken, IRBuilder<> &  Builder, GCStrategy *  GC  )

static

Helper function to place all gc relocates necessary for the given statepoint.

Inputs: liveVariables - list of variables to be relocated. basePtrs - base pointers. statepointToken - statepoint instruction to which relocates should be bound. Builder - Llvm IR builder to be used to construct new calls.

Definition at line 1502 of file RewriteStatepointsForGC.cpp.

References assert(), llvm::ArrayRef< T >::begin(), llvm::CallingConv::Cold, llvm::IRBuilderBase::CreateCall(), llvm::ArrayRef< T >::end(), llvm::find(), llvm::PointerType::get(), llvm::FixedVectorType::get(), llvm::IRBuilderBase::getInt32(), llvm::Instruction::getModule(), getNumElements(), llvm::Intrinsic::getOrInsertDeclaration(), Index, isHandledGCPointerType(), llvm::CallBase::setCallingConv(), llvm::ArrayRef< T >::size(), suffixed_name_or(), and llvm::DenseMapBase< DerivedT, KeyT, ValueT, KeyInfoT, BucketT >::try_emplace().

Referenced by makeStatepointExplicitImpl().

findBaseDefiningValue()

static Value * findBaseDefiningValue ( Value *  I, DefiningValueMapTy &  Cache, IsKnownBaseMapTy &  KnownBases  )

static

Helper function for findBasePointer - Will return a value which either a) defines the base pointer for the input, b) blocks the simple search (i.e.

a PHI or Select of two derived pointers), or c) involves a change from pointer to vector type or back.

Definition at line 449 of file RewriteStatepointsForGC.cpp.

References assert(), findBaseDefiningValue(), findBaseDefiningValueOfVector(), GEP, llvm::ConstantPointerNull::get(), I, II, llvm_unreachable, setKnownBase(), and llvm::AtomicRMWInst::Xchg.

Referenced by findBaseDefiningValue(), findBaseDefiningValueCached(), and findBaseDefiningValueOfVector().

findBaseDefiningValueCached()

static Value * findBaseDefiningValueCached ( Value *  I, DefiningValueMapTy &  Cache, IsKnownBaseMapTy &  KnownBases  )

static

Returns the base defining value for this value.

Definition at line 630 of file RewriteStatepointsForGC.cpp.

References assert(), llvm::dbgs(), findBaseDefiningValue(), I, and LLVM_DEBUG.

Referenced by findBaseOrBDV().

findBaseDefiningValueOfVector()

static Value * findBaseDefiningValueOfVector ( Value *  I, DefiningValueMapTy &  Cache, IsKnownBaseMapTy &  KnownBases  )

static

Return a base defining value for the 'Index' element of the given vector instruction 'I'.

If Index is null, returns a BDV for the entire vector 'I'. As an optimization, this method will try to determine when the element is known to already be a base pointer. If this can be established, the second value in the returned pair will be true. Note that either a vector or a pointer typed value can be returned. For the former, the vector returned is a BDV (and possibly a base) of the entire vector 'I'. If the later, the return pointer is a BDV (or possibly a base) for the particular element in 'I'.

Definition at line 351 of file RewriteStatepointsForGC.cpp.

References assert(), findBaseDefiningValue(), GEP, llvm::ConstantAggregateZero::get(), I, and setKnownBase().

Referenced by findBaseDefiningValue().

findBaseOrBDV()

static Value * findBaseOrBDV ( Value *  I, DefiningValueMapTy &  Cache, IsKnownBaseMapTy &  KnownBases  )

static

Return a base pointer for this value if known.

Otherwise, return it's base defining value.

Definition at line 647 of file RewriteStatepointsForGC.cpp.

References findBaseDefiningValueCached(), and I.

Referenced by findBasePointer().

findBasePointer()

static Value * findBasePointer ( Value *  I, DefiningValueMapTy &  Cache, IsKnownBaseMapTy &  KnownBases  )

static

For a given value or instruction, figure out what base ptr its derived from.

For gc objects, this is simply itself. On success, returns a value which is the base pointer. (This is reliable and can be used for relocation.) On failure, returns nullptr.

Definition at line 811 of file RewriteStatepointsForGC.cpp.

References areBothVectorOrScalar(), assert(), llvm::sampleprof::Base, llvm::MapVector< KeyT, ValueT, MapType, VectorType >::count(), llvm::dbgs(), DL, llvm::SmallVectorBase< Size_T >::empty(), llvm::MapVector< KeyT, ValueT, MapType, VectorType >::end(), F, llvm::MapVector< KeyT, ValueT, MapType, VectorType >::find(), findBaseOrBDV(), llvm::MDNode::get(), llvm::PoisonValue::get(), llvm::PHINode::getIncomingBlock(), llvm::PHINode::getIncomingValue(), llvm::Value::getName(), llvm::PHINode::getNumIncomingValues(), llvm::BasicBlock::getTerminator(), llvm::Value::getType(), I, llvm::MapVector< KeyT, ValueT, MapType, VectorType >::insert(), llvm::Instruction::insertBefore(), isKnownBase(), isOriginalBaseResult(), LLVM_DEBUG, llvm_unreachable, llvm::SmallVectorImpl< T >::pop_back_val(), llvm::SmallVectorTemplateBase< T, bool >::push_back(), setKnownBase(), llvm::Instruction::setMetadata(), llvm::Value::setName(), llvm::MapVector< KeyT, ValueT, MapType, VectorType >::size(), suffixed_name_or(), ToRemove, and llvm::DenseMapBase< DerivedT, KeyT, ValueT, KeyInfoT, BucketT >::try_emplace().

Referenced by findBasePointers(), and inlineGetBaseAndOffset().

findBasePointers() [1/2]

static void findBasePointers ( const StatepointLiveSetTy &  live, PointerToBaseTy &  PointerToBase, DominatorTree *  DT, DefiningValueMapTy &  DVCache, IsKnownBaseMapTy &  KnownBases  )

static

Definition at line 1307 of file RewriteStatepointsForGC.cpp.

References assert(), llvm::DominatorTree::dominates(), findBasePointer(), and live.

Referenced by findBasePointers(), and insertParsePoints().

findBasePointers() [2/2]

static void findBasePointers ( DominatorTree &  DT, DefiningValueMapTy &  DVCache, CallBase *  Call, PartiallyConstructedSafepointRecord &  result, PointerToBaseTy &  PointerToBase, IsKnownBaseMapTy &  KnownBases  )

static

Find the required based pointers (and adjust the live set) for the given parse point.

Definition at line 1324 of file RewriteStatepointsForGC.cpp.

References findBasePointers(), and llvm::LLVMContext::OB_deopt.

findGCStrategy()

static std::unique_ptr< GCStrategy > findGCStrategy ( Function &  F )

static

Looks up the GC strategy for a given function, returning null if the function doesn't have a GC tag.

The strategy is stored in the cache.

Definition at line 2996 of file RewriteStatepointsForGC.cpp.

References F, and llvm::getGCStrategy().

Referenced by insertParsePoints(), and shouldRewriteStatepointsIn().

findLiveReferences()

static void findLiveReferences ( Function &  F, DominatorTree &  DT, ArrayRef< CallBase * >  toUpdate, MutableArrayRef< struct PartiallyConstructedSafepointRecord >  records, GCStrategy *  GC  )

static

Definition at line 2243 of file RewriteStatepointsForGC.cpp.

References analyzeParsePointLiveness(), computeLiveInValues(), F, info, and llvm::ArrayRef< T >::size().

Referenced by insertParsePoints().

findLiveSetAtInst()

static void findLiveSetAtInst ( Instruction *  inst, GCPtrLivenessData &  Data, StatepointLiveSetTy &  out, GCStrategy *  GC  )

static

Given results from the dataflow liveness computation, find the set of live Values at a particular instruction.

Definition at line 3344 of file RewriteStatepointsForGC.cpp.

References assert(), computeLiveInValues(), llvm::Data, llvm::ilist_node_impl< OptionsT >::getIterator(), llvm::ilist_detail::node_parent_access< NodeTy, ParentTy >::getParent(), llvm::BasicBlock::rbegin(), and llvm::SetVector< T, Vector, Set, N >::remove().

Referenced by analyzeParsePointLiveness(), and recomputeLiveInValues().

findRematerializableChainToBasePointer()

static Value * findRematerializableChainToBasePointer ( SmallVectorImpl< Instruction * > &  ChainToBase, Value *  CurrentValue  )

static

Definition at line 2261 of file RewriteStatepointsForGC.cpp.

References findRematerializableChainToBasePointer(), GEP, and llvm::SmallVectorTemplateBase< T, bool >::push_back().

Referenced by findRematerializableChainToBasePointer(), findRematerializationCandidates(), and rematerializeLiveValuesAtUses().

findRematerializationCandidates()

static void findRematerializationCandidates ( PointerToBaseTy  PointerToBase, RematCandTy &  RematerizationCandidates, TargetTransformInfo &  TTI  )

static

Definition at line 2350 of file RewriteStatepointsForGC.cpp.

References AreEquivalentPhiNodes(), llvm::sampleprof::Base, chainToBasePointerCost(), findRematerializableChainToBasePointer(), and llvm::SmallVectorBase< Size_T >::size().

Referenced by insertParsePoints().

GetDeoptBundleOperands()

static ArrayRef< Use > GetDeoptBundleOperands ( const CallBase *  Call )

static

Definition at line 230 of file RewriteStatepointsForGC.cpp.

References AllowStatepointWithNoDeoptInfo, assert(), and llvm::LLVMContext::OB_deopt.

Referenced by insertParsePoints().

getDeoptLowering()

static StringRef getDeoptLowering ( CallBase *  Call )

static

Definition at line 1631 of file RewriteStatepointsForGC.cpp.

References assert(), F, llvm::AttributeList::getFnAttr(), llvm::Attribute::getValueAsString(), and llvm::AttributeList::hasFnAttr().

Referenced by makeStatepointExplicitImpl().

getParamAndReturnAttributesToRemove()

static AttributeMask getParamAndReturnAttributesToRemove ( )

static

Definition at line 2878 of file RewriteStatepointsForGC.cpp.

Referenced by stripNonValidAttributesFromPrototype(), and stripNonValidDataFromBody().

inlineGetBaseAndOffset()

static bool inlineGetBaseAndOffset ( Function &  F, SmallVectorImpl< CallInst * > &  Intrinsics, DefiningValueMapTy &  DVCache, IsKnownBaseMapTy &  KnownBases  )

static

Definition at line 2598 of file RewriteStatepointsForGC.cpp.

References assert(), llvm::sampleprof::Base, Context, llvm::IRBuilderBase::CreatePtrToInt(), llvm::IRBuilderBase::CreateSub(), DL, F, findBasePointer(), llvm::Type::getIntNTy(), llvm::Type::getPointerAddressSpace(), llvm::Value::getType(), llvm_unreachable, llvm::Offset, llvm::Value::replaceAllUsesWith(), and suffixed_name_or().

Referenced by llvm::RewriteStatepointsForGC::runOnFunction().

insertParsePoints()

static bool insertParsePoints ( Function &  F, DominatorTree &  DT, TargetTransformInfo &  TTI, SmallVectorImpl< CallBase * > &  ToUpdate, DefiningValueMapTy &  DVCache, IsKnownBaseMapTy &  KnownBases  )

static

Global mapping from live pointers to a base-defining-value.

Definition at line 2646 of file RewriteStatepointsForGC.cpp.

References assert(), llvm::SmallVectorTemplateCommon< T, typename >::begin(), llvm::SmallVectorImpl< T >::clear(), llvm::DominatorTree::dominates(), llvm::SmallVectorTemplateCommon< T, typename >::end(), llvm::errs(), F, findBasePointers(), findGCStrategy(), findLiveReferences(), findRematerializationCandidates(), GetDeoptBundleOperands(), II, info, Info, insertUseHolderAfter(), isHandledGCPointerType(), llvm::DominatorTree::isReachableFromEntry(), isUnhandledGCPointerType(), Live, makeStatepointExplicit(), normalizeForInvokeSafepoint(), PrintBasePointers, Ptr, llvm::SmallVectorTemplateBase< T, bool >::push_back(), recomputeLiveInValues(), relocationViaAlloca(), rematerializeLiveValues(), rematerializeLiveValuesAtUses(), llvm::SmallVectorImpl< T >::reserve(), and llvm::SmallVectorBase< Size_T >::size().

Referenced by llvm::RewriteStatepointsForGC::runOnFunction().

insertRelocationStores()

static void insertRelocationStores ( iterator_range< Value::user_iterator >  GCRelocs, DenseMap< Value *, AllocaInst * > &  AllocaMap, DenseSet< Value * > &  VisitedLiveValues  )

static

Definition at line 1970 of file RewriteStatepointsForGC.cpp.

References assert(), llvm::DenseMapBase< DerivedT, KeyT, ValueT, KeyInfoT, BucketT >::count(), llvm::GCRelocateInst::getDerivedPtr(), llvm::ilist_node_impl< OptionsT >::getIterator(), llvm::ilist_node_with_parent< NodeTy, ParentTy, Options >::getNextNode(), and llvm::detail::DenseSetImpl< ValueT, MapTy, ValueInfoT >::insert().

Referenced by relocationViaAlloca().

insertRematerializationStores()

static void insertRematerializationStores ( const RematerializedValueMapTy &  RematerializedValues, DenseMap< Value *, AllocaInst * > &  AllocaMap, DenseSet< Value * > &  VisitedLiveValues  )

static

Definition at line 1995 of file RewriteStatepointsForGC.cpp.

References assert(), llvm::DenseMapBase< DerivedT, KeyT, ValueT, KeyInfoT, BucketT >::count(), llvm::ilist_node_impl< OptionsT >::getIterator(), and llvm::detail::DenseSetImpl< ValueT, MapTy, ValueInfoT >::insert().

Referenced by relocationViaAlloca().

insertUseHolderAfter()

static void insertUseHolderAfter ( CallBase *  Call, const ArrayRef< Value * >  Values, SmallVectorImpl< CallInst * > &  Holders  )

static

Insert holders so that each Value is obviously live through the entire lifetime of the call.

Definition at line 2218 of file RewriteStatepointsForGC.cpp.

References llvm::CallInst::Create(), llvm::ArrayRef< T >::empty(), llvm::FunctionType::get(), llvm::Type::getVoidTy(), II, and llvm::SmallVectorTemplateBase< T, bool >::push_back().

Referenced by insertParsePoints().

isGCPointerType()

static bool isGCPointerType ( Type *  T, GCStrategy *  GC  )

static

Definition at line 252 of file RewriteStatepointsForGC.cpp.

References assert().

isHandledGCPointerType()

static bool isHandledGCPointerType ( Type *  T, GCStrategy *  GC  )

static

Definition at line 266 of file RewriteStatepointsForGC.cpp.

References isGCPointerType().

Referenced by computeKillSet(), computeLiveInValues(), computeLiveOutSeed(), CreateGCRelocates(), insertParsePoints(), and isUnhandledGCPointerType().

isKnownBase()

static bool isKnownBase ( Value *  V, const IsKnownBaseMapTy &  KnownBases  )

static

Returns true if V is a known base.

Definition at line 670 of file RewriteStatepointsForGC.cpp.

References assert().

Referenced by findBasePointer().

isOriginalBaseResult()

static bool isOriginalBaseResult ( Value *  V )

static

This value is a base pointer that is not generated by RS4GC, i.e.

it already exists in the code.

Definition at line 662 of file RewriteStatepointsForGC.cpp.

Referenced by findBasePointer().

isUnhandledGCPointerType()

static bool isUnhandledGCPointerType ( Type *  Ty, GCStrategy *  GC  )

static

Definition at line 297 of file RewriteStatepointsForGC.cpp.

References containsGCPtrType(), and isHandledGCPointerType().

Referenced by computeLiveInValues(), computeLiveOutSeed(), and insertParsePoints().

legalizeCallAttributes()

static AttributeList legalizeCallAttributes ( CallBase *  Call, bool  IsMemIntrinsic, AttributeList  StatepointAL  )

static

Definition at line 1457 of file RewriteStatepointsForGC.cpp.

References A, llvm::AttributeList::addFnAttributes(), llvm::AttributeList::addParamAttributes(), llvm::GCStatepointInst::CallArgsBeginPos, FnAttrsToStrip, llvm::AttributeList::getFnAttrs(), llvm::AttributeList::getParamAttrs(), I, llvm::AttributeList::isEmpty(), llvm::isStatepointDirectiveAttr(), llvm::AttrBuilder::removeAttribute(), and llvm::seq().

Referenced by makeStatepointExplicitImpl().

makeStatepointExplicit()

static void makeStatepointExplicit ( DominatorTree &  DT, CallBase *  Call, PartiallyConstructedSafepointRecord &  Result, std::vector< DeferredReplacement > &  Replacements, const PointerToBaseTy &  PointerToBase, GCStrategy *  GC  )

static

Definition at line 1940 of file RewriteStatepointsForGC.cpp.

References assert(), llvm::sampleprof::Base, makeStatepointExplicitImpl(), llvm::SmallVectorTemplateBase< T, bool >::push_back(), llvm::SmallVectorImpl< T >::reserve(), and llvm::SmallVectorBase< Size_T >::size().

Referenced by insertParsePoints().

makeStatepointExplicitImpl()

static void makeStatepointExplicitImpl ( CallBase *  Call, const SmallVectorImpl< Value * > &  BasePtrs, const SmallVectorImpl< Value * > &  LiveVariables, PartiallyConstructedSafepointRecord &  Result, std::vector< DeferredReplacement > &  Replacements, const PointerToBaseTy &  PointerToBase, GCStrategy *  GC  )

static

Definition at line 1647 of file RewriteStatepointsForGC.cpp.

References assert(), llvm::sampleprof::Base, llvm::BasicBlock::begin(), llvm::SmallVectorImpl< T >::clear(), Context, CreateGCRelocates(), llvm::IRBuilderBase::CreateGCResult(), llvm::IRBuilderBase::CreateGCStatepointCall(), llvm::IRBuilderBase::CreateGCStatepointInvoke(), llvm::IRBuilderBase::CreatePtrToInt(), llvm::IRBuilderBase::CreateSub(), llvm::StatepointDirectives::DefaultStatepointID, llvm::DeoptLiveIn, DL, F, llvm::GCTransition, llvm::AttributeList::get(), llvm::ConstantPointerNull::get(), llvm::FunctionType::get(), llvm::CallBase::getAttributes(), llvm::FunctionCallee::getCallee(), llvm::Value::getContext(), getDeoptLowering(), llvm::BasicBlock::getFirstInsertionPt(), llvm::Type::getIntNTy(), llvm::BasicBlock::getLandingPadInst(), llvm::BasicBlock::getUniquePredecessor(), llvm::Type::getVoidTy(), II, legalizeCallAttributes(), llvm_unreachable, Name, llvm::None, llvm::StatepointDirectives::NumPatchBytes, llvm::LLVMContext::OB_deopt, llvm::LLVMContext::OB_gc_transition, llvm::parseStatepointDirectivesFromAttrs(), llvm::SmallVectorTemplateBase< T, bool >::push_back(), llvm::AttributeList::ReturnIndex, llvm::CallBase::setAttributes(), llvm::CallBase::setCallingConv(), llvm::IRBuilderBase::SetCurrentDebugLocation(), llvm::IRBuilderBase::SetInsertPoint(), llvm::Value::setName(), llvm::CallInst::setTailCallKind(), llvm::SmallVectorBase< Size_T >::size(), and llvm::StatepointDirectives::StatepointID.

Referenced by makeStatepointExplicit().

normalizeForInvokeSafepoint()

static BasicBlock * normalizeForInvokeSafepoint ( BasicBlock *  BB, BasicBlock *  InvokeParent, DominatorTree &  DT  )

static

Definition at line 1430 of file RewriteStatepointsForGC.cpp.

References assert(), llvm::FoldSingleEntryPHINodes(), llvm::BasicBlock::getUniquePredecessor(), and llvm::SplitBlockPredecessors().

Referenced by insertParsePoints().

operator<<()

static raw_ostream & operator<< ( raw_ostream &  OS, const BDVState &  State  )

static

Definition at line 801 of file RewriteStatepointsForGC.cpp.

References OS.

recomputeLiveInValues() [1/2]

static void recomputeLiveInValues ( Function &  F, DominatorTree &  DT, ArrayRef< CallBase * >  toUpdate, MutableArrayRef< struct PartiallyConstructedSafepointRecord >  records, PointerToBaseTy &  PointerToBase, GCStrategy *  GC  )

static

Definition at line 1354 of file RewriteStatepointsForGC.cpp.

References computeLiveInValues(), F, info, recomputeLiveInValues(), and llvm::ArrayRef< T >::size().

recomputeLiveInValues() [2/2]

static void recomputeLiveInValues ( GCPtrLivenessData &  RevisedLivenessData, CallBase *  Call, PartiallyConstructedSafepointRecord &  result, PointerToBaseTy &  PointerToBase, GCStrategy *  GC  )

static

Given an updated version of the dataflow liveness results, update the liveset and base pointer maps for the call site CS.

Definition at line 3362 of file RewriteStatepointsForGC.cpp.

References findLiveSetAtInst(), and Info.

Referenced by insertParsePoints(), and recomputeLiveInValues().

relocationViaAlloca()

static void relocationViaAlloca ( Function &  F, DominatorTree &  DT, ArrayRef< Value * >  Live, ArrayRef< PartiallyConstructedSafepointRecord >  Records  )

static

Do all the relocation update via allocas and mem2reg.

Definition at line 2017 of file RewriteStatepointsForGC.cpp.

References assert(), ClobberNonLive, llvm::DenseMapBase< DerivedT, KeyT, ValueT, KeyInfoT, BucketT >::contains(), llvm::detail::DenseSetImpl< ValueT, MapTy, ValueInfoT >::count(), DL, llvm::SmallVectorBase< Size_T >::empty(), F, llvm::ConstantPointerNull::get(), llvm::ConstantAggregateZero::get(), llvm::AllocaInst::getAllocatedType(), llvm::BasicBlock::getFirstNonPHIIt(), I, II, Info, insertRelocationStores(), insertRematerializationStores(), llvm::Last, Live, llvm::PromoteMemToReg(), llvm::SmallVectorTemplateBase< T, bool >::push_back(), llvm::SmallVectorImpl< T >::reserve(), llvm::SmallVectorBase< Size_T >::size(), llvm::sort(), llvm::unique(), llvm::Value::users(), and Uses.

Referenced by insertParsePoints().

rematerializeChain()

static Instruction * rematerializeChain ( ArrayRef< Instruction * >  ChainToBase, BasicBlock::iterator  InsertBefore, Value *  RootOfChain, Value *  AlternateLiveBase  )

static

Definition at line 1372 of file RewriteStatepointsForGC.cpp.

References assert(), llvm::Instruction::insertBefore(), llvm::is_contained(), llvm::User::operand_values(), llvm::User::replaceUsesOfWith(), llvm::reverse(), and llvm::Value::setName().

Referenced by rematerializeLiveValues(), and rematerializeLiveValuesAtUses().

rematerializeLiveValues()

static void rematerializeLiveValues ( CallBase *  Call, PartiallyConstructedSafepointRecord &  Info, PointerToBaseTy &  PointerToBase, RematCandTy &  RematerizationCandidates, TargetTransformInfo &  TTI  )

static

Definition at line 2532 of file RewriteStatepointsForGC.cpp.

References assert(), llvm::ilist_node_impl< OptionsT >::getIterator(), Info, llvm::SmallVectorTemplateBase< T, bool >::push_back(), RematerializationThreshold, and rematerializeChain().

Referenced by insertParsePoints().

rematerializeLiveValuesAtUses()

static void rematerializeLiveValuesAtUses ( RematCandTy &  RematerizationCandidates, MutableArrayRef< PartiallyConstructedSafepointRecord >  Records, PointerToBaseTy &  PointerToBase  )

static

Definition at line 2411 of file RewriteStatepointsForGC.cpp.

References llvm::any_of(), assert(), llvm::count_if(), llvm::dbgs(), llvm::SmallVectorBase< Size_T >::empty(), findRematerializableChainToBasePointer(), llvm::ilist_node_impl< OptionsT >::getIterator(), llvm::Value::getNumUses(), llvm::ilist_detail::node_parent_access< NodeTy, ParentTy >::getParent(), llvm::Value::getUniqueUndroppableUser(), llvm::Value::hasOneUse(), LLVM_DEBUG, P, llvm::SmallVectorTemplateBase< T, bool >::push_back(), RematDerivedAtUses, RematerializationThreshold, rematerializeChain(), llvm::User::replaceUsesOfWith(), llvm::SmallVectorBase< Size_T >::size(), llvm::Value::user_begin(), llvm::Value::user_empty(), and llvm::Value::users().

Referenced by insertParsePoints().

setKnownBase()

static void setKnownBase ( Value *  V, bool  IsKnownBase, IsKnownBaseMapTy &  KnownBases  )

static

Caches the IsKnownBase flag for a value and asserts that it wasn't present in the cache before.

Definition at line 676 of file RewriteStatepointsForGC.cpp.

References assert().

Referenced by findBaseDefiningValue(), findBaseDefiningValueOfVector(), and findBasePointer().

shouldRewriteStatepointsIn()

static bool shouldRewriteStatepointsIn ( Function &  F )

static

Returns true if this function should be rewritten by this pass.

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

Definition at line 3005 of file RewriteStatepointsForGC.cpp.

References assert(), F, and findGCStrategy().

Referenced by llvm::RewriteStatepointsForGC::run(), llvm::RewriteStatepointsForGC::runOnFunction(), and stripNonValidData().

stripInvalidMetadataFromInstruction()

static void stripInvalidMetadataFromInstruction ( Instruction &  I )

static

Certain metadata on instructions are invalid after running RS4GC.

Optimizations that run after RS4GC can incorrectly use this metadata to optimize functions. We drop such metadata on the instruction.

Definition at line 2918 of file RewriteStatepointsForGC.cpp.

References I.

Referenced by stripNonValidDataFromBody().

stripNonValidAttributesFromPrototype()

static void stripNonValidAttributesFromPrototype ( Function &  F )

static

Definition at line 2890 of file RewriteStatepointsForGC.cpp.

References A, F, FnAttrsToStrip, llvm::Intrinsic::getAttributes(), and getParamAndReturnAttributesToRemove().

Referenced by stripNonValidData().

stripNonValidData()

static void stripNonValidData ( Module &  M )

static

The IR fed into RewriteStatepointsForGC may have had attributes and metadata implying dereferenceability that are no longer valid/correct after RewriteStatepointsForGC has run.

This is because semantically, after RewriteStatepointsForGC runs, all calls to gc.statepoint "free" the entire heap. stripNonValidData (conservatively) restores correctness by erasing all attributes in the module that externally imply dereferenceability. Similar reasoning also applies to the noalias attributes and metadata. gc.statepoint can touch the entire heap including noalias objects. Apart from attributes and metadata, we also remove instructions that imply constant physical memory: llvm.invariant.start.

Definition at line 3016 of file RewriteStatepointsForGC.cpp.

References llvm::any_of(), assert(), F, shouldRewriteStatepointsIn(), stripNonValidAttributesFromPrototype(), and stripNonValidDataFromBody().

Referenced by llvm::RewriteStatepointsForGC::run().

stripNonValidDataFromBody()

static void stripNonValidDataFromBody ( Function &  F )

static

Definition at line 2946 of file RewriteStatepointsForGC.cpp.

References llvm::MDBuilder::createMutableTBAAAccessTag(), F, llvm::PoisonValue::get(), getParamAndReturnAttributesToRemove(), I, II, instructions, llvm::SmallVectorTemplateBase< T, bool >::push_back(), stripInvalidMetadataFromInstruction(), and llvm::Tag.

Referenced by stripNonValidData().

suffixed_name_or()

static std::string suffixed_name_or ( Value *  V, StringRef  Suffix, StringRef  DefaultName  )

static

Definition at line 304 of file RewriteStatepointsForGC.cpp.

References llvm::StringRef::str().

Referenced by CreateGCRelocates(), findBasePointer(), and inlineGetBaseAndOffset().

Variable Documentation

AllowStatepointWithNoDeoptInfo

cl::opt< bool > AllowStatepointWithNoDeoptInfo("rs4gc-allow-statepoint-with-no-deopt-info", cl::Hidden, cl::init(true)) ( "rs4gc-allow-statepoint-with-no-deopt-info"  , cl::Hidden  , cl::init(true)    )

static

Referenced by GetDeoptBundleOperands(), and llvm::RewriteStatepointsForGC::runOnFunction().

ClobberNonLive

bool ClobberNonLive = false

static

Definition at line 99 of file RewriteStatepointsForGC.cpp.

Referenced by relocationViaAlloca().

ClobberNonLiveOverride

cl::opt< bool, true > ClobberNonLiveOverride("rs4gc-clobber-non-live", cl::location(ClobberNonLive), cl::Hidden) ( "rs4gc-clobber-non-live"  , cl::location(ClobberNonLive)  , cl::Hidden    )

static

FnAttrsToStrip

constexpr Attribute::AttrKind FnAttrsToStrip[]

staticconstexpr

Initial value:

=
  {Attribute::Memory, Attribute::NoSync, Attribute::NoFree}

Definition at line 1452 of file RewriteStatepointsForGC.cpp.

Referenced by legalizeCallAttributes(), and stripNonValidAttributesFromPrototype().

PrintBasePointers

cl::opt< bool > PrintBasePointers("spp-print-base-pointers", cl::Hidden, cl::init(false)) ( "spp-print-base-pointers"  , cl::Hidden  , cl::init(false)    )

static

Referenced by insertParsePoints().

PrintLiveSet

cl::opt< bool > PrintLiveSet("spp-print-liveset", cl::Hidden, cl::init(false)) ( "spp-print-liveset"  , cl::Hidden  , cl::init(false)    )

static

Referenced by analyzeParsePointLiveness().

PrintLiveSetSize

cl::opt< bool > PrintLiveSetSize("spp-print-liveset-size", cl::Hidden, cl::init(false)) ( "spp-print-liveset-size"  , cl::Hidden  , cl::init(false)    )

static

Referenced by analyzeParsePointLiveness().

RematDerivedAtUses

cl::opt< bool > RematDerivedAtUses("rs4gc-remat-derived-at-uses", cl::Hidden, cl::init(true)) ( "rs4gc-remat-derived-at-uses"  , cl::Hidden  , cl::init(true)    )

static

Referenced by rematerializeLiveValuesAtUses().

RematerializationThreshold

cl::opt< unsigned > RematerializationThreshold("spp-rematerialization-threshold", cl::Hidden, cl::init(6)) ( "spp-rematerialization-threshold"  , cl::Hidden  , cl::init(6)    )

static

Referenced by rematerializeLiveValues(), and rematerializeLiveValuesAtUses().