LLVM  8.0.1
Macros | Functions | Variables
PlaceSafepoints.cpp File Reference
#include "llvm/Pass.h"
#include "llvm/ADT/SetVector.h"
#include "llvm/ADT/Statistic.h"
#include "llvm/Analysis/CFG.h"
#include "llvm/Analysis/ScalarEvolution.h"
#include "llvm/Analysis/TargetLibraryInfo.h"
#include "llvm/Transforms/Utils/Local.h"
#include "llvm/IR/CallSite.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 dependency graph for PlaceSafepoints.cpp:

Go to the source code of this file.

Macros

#define DEBUG_TYPE   "safepoint-placement"
 

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")
 
static void InsertSafepointPoll (Instruction *InsertBefore, std::vector< CallSite > &ParsePointsNeeded, const TargetLibraryInfo &TLI)
 
static bool needsStatepoint (const CallSite &CS, const TargetLibraryInfo &TLI)
 
static 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. More...
 
static bool mustBeFiniteCountedLoop (Loop *L, ScalarEvolution *SE, BasicBlock *Pred)
 Returns true if this loop is known to terminate in a finite number of iterations. More...
 
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 (const CallSite &CS)
 Returns true if an entry safepoint is not required before this callsite in the caller function. More...
 
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. More...
 
static bool enableEntrySafepoints (Function &F)
 
static bool enableBackedgeSafepoints (Function &F)
 
static bool enableCallSafepoints (Function &F)
 
 INITIALIZE_PASS_BEGIN (PlaceBackedgeSafepointsImpl, "place-backedge-safepoints-impl", "Place Backedge Safepoints", false, false) INITIALIZE_PASS_END(PlaceBackedgeSafepointsImpl
 
place backedge safepoints Place Backedge false INITIALIZE_PASS_BEGIN (PlaceSafepoints, "place-safepoints", "Place Safepoints", false, false) INITIALIZE_PASS_END(PlaceSafepoints
 

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. More...
 
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))
 
static const char *const GCSafepointPollName = "gc.safepoint_poll"
 
place backedge safepoints impl
 
place backedge safepoints Place Backedge Safepoints
 
place backedge safepoints Place Backedge false
 
place backedge safepoints Place Backedge false place safepoints
 

Macro Definition Documentation

◆ DEBUG_TYPE

#define DEBUG_TYPE   "safepoint-placement"

Definition at line 70 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 201 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 ( const CallSite &  CS)
static

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

Definition at line 363 of file PlaceSafepoints.cpp.

References llvm::Intrinsic::experimental_gc_statepoint, llvm::Intrinsic::experimental_patchpoint_i64, llvm::Intrinsic::experimental_patchpoint_void, and llvm::CallSiteBase< FunTy, BBTy, ValTy, UserTy, UseTy, InstrTy, CallTy, InvokeTy, IterTy >::getInstruction().

Referenced by findLocationForEntrySafepoint().

◆ enableBackedgeSafepoints()

static bool enableBackedgeSafepoints ( Function &  F)
static

Definition at line 464 of file PlaceSafepoints.cpp.

References NoBackedge.

Referenced by enableCallSafepoints().

◆ enableCallSafepoints()

static bool enableCallSafepoints ( Function &  F)
static

Definition at line 465 of file PlaceSafepoints.cpp.

References assert(), llvm::DominatorTree::dominates(), llvm::SetVector< T, Vector, Set >::empty(), llvm::Function::empty(), enableBackedgeSafepoints(), enableEntrySafepoints(), F(), findLocationForEntrySafepoint(), llvm::Value::getName(), llvm::Instruction::getParent(), llvm::BasicBlock::getParent(), llvm::GlobalValue::getParent(), llvm::BasicBlock::getTerminator(), llvm::SetVector< T, Vector, Set >::insert(), InsertSafepointPoll(), llvm::GlobalValue::isDeclaration(), isGCSafepointPoll(), Modified, NoCall, llvm::SmallVectorTemplateBase< T >::push_back(), llvm::DominatorTreeBase< NodeT, IsPostDom >::recalculate(), llvm::removeUnreachableBlocks(), runOnFunction(), shouldRewriteFunction(), llvm::sort(), SplitBackedge, and llvm::SplitEdge().

◆ enableEntrySafepoints()

static bool enableEntrySafepoints ( Function &  F)
static

Definition at line 463 of file PlaceSafepoints.cpp.

References NoEntry.

Referenced by enableCallSafepoints().

◆ findLocationForEntrySafepoint()

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

Definition at line 387 of file PlaceSafepoints.cpp.

References assert(), doesNotRequireEntrySafepointBefore(), llvm::BasicBlock::front(), llvm::Function::getEntryBlock(), llvm::BasicBlock::getUniquePredecessor(), I, and llvm::Instruction::isTerminator().

Referenced by enableCallSafepoints().

◆ INITIALIZE_PASS_BEGIN() [1/2]

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

Referenced by llvm::createPlaceSafepointsPass().

◆ INITIALIZE_PASS_BEGIN() [2/2]

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

◆ InsertSafepointPoll()

place backedge safepoints Place Backedge false place Place static false void InsertSafepointPoll ( Instruction *  InsertBefore,
std::vector< CallSite > &  ParsePointsNeeded,
const TargetLibraryInfo &  TLI 
)
static

Definition at line 624 of file PlaceSafepoints.cpp.

References assert(), llvm::BasicBlock::begin(), llvm::CallInst::Create(), llvm::Function::empty(), llvm::BasicBlock::end(), llvm::FunctionType::get(), llvm::Module::getContext(), llvm::Module::getFunction(), llvm::BasicBlock::getParent(), llvm::GlobalValue::getValueType(), llvm::Type::getVoidTy(), and llvm::InlineFunction().

Referenced by enableCallSafepoints().

◆ isGCSafepointPoll()

static bool isGCSafepointPoll ( Function &  F)
static

Definition at line 442 of file PlaceSafepoints.cpp.

References llvm::StringRef::equals(), and llvm::Value::getName().

Referenced by enableCallSafepoints().

◆ 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 243 of file PlaceSafepoints.cpp.

References CountedLoopTripWidth, llvm::ScalarEvolution::getCouldNotCompute(), llvm::ScalarEvolution::getExitCount(), llvm::ScalarEvolution::getMaxBackedgeTakenCount(), llvm::ConstantRange::getUnsignedMax(), llvm::ScalarEvolution::getUnsignedRange(), llvm::APInt::isIntN(), and llvm::LoopBase< BlockT, LoopT >::isLoopExiting().

◆ needsStatepoint()

static bool needsStatepoint ( const CallSite &  CS,
const TargetLibraryInfo &  TLI 
)
static

Definition at line 185 of file PlaceSafepoints.cpp.

References llvm::callsGCLeafFunction(), llvm::CallSiteBase< FunTy, BBTy, ValTy, UserTy, UseTy, InstrTy, CallTy, InvokeTy, IterTy >::getInstruction(), llvm::CallSiteBase< FunTy, BBTy, ValTy, UserTy, UseTy, InstrTy, CallTy, InvokeTy, IterTy >::isCall(), llvm::isGCRelocate(), llvm::isGCResult(), llvm::CallInst::isInlineAsm(), and llvm::isStatepoint().

Referenced by containsUnconditionalCallSafepoint().

◆ scanInlinedCode()

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

Definition at line 295 of file PlaceSafepoints.cpp.

◆ scanOneBB()

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

Definition at line 268 of file PlaceSafepoints.cpp.

◆ 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 449 of file PlaceSafepoints.cpp.

References llvm::Function::getGC(), and llvm::Function::hasGC().

Referenced by enableCallSafepoints().

◆ STATISTIC() [1/4]

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

◆ STATISTIC() [2/4]

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

◆ STATISTIC() [3/4]

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

◆ STATISTIC() [4/4]

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

Variable Documentation

◆ AllBackedges

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

◆ CountedLoopTripWidth

cl::opt<int> CountedLoopTripWidth("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 place Place false

Definition at line 615 of file PlaceSafepoints.cpp.

◆ GCSafepointPollName

const char* const GCSafepointPollName = "gc.safepoint_poll"
static

Definition at line 440 of file PlaceSafepoints.cpp.

◆ impl

place backedge safepoints impl

Definition at line 615 of file PlaceSafepoints.cpp.

◆ NoBackedge

cl::opt<bool> NoBackedge("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))
static

Referenced by enableCallSafepoints().

◆ NoEntry

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

Referenced by enableEntrySafepoints().

◆ Safepoints

place backedge safepoints Place Backedge false place Place Safepoints

Definition at line 615 of file PlaceSafepoints.cpp.

◆ safepoints

place backedge safepoints Place Backedge false place safepoints

Definition at line 620 of file PlaceSafepoints.cpp.

◆ SplitBackedge

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

Referenced by enableCallSafepoints().

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