/// Inlines all mandatory inlined functions into the body of a function, /// first recursively inlining all mandatory apply instructions in those /// functions into their bodies if necessary. /// /// \param F the function to be processed /// \param AI nullptr if this is being called from the top level; the relevant /// ApplyInst requiring the recursive call when non-null /// \param FullyInlinedSet the set of all functions already known to be fully /// processed, to avoid processing them over again /// \param SetFactory an instance of ImmutableFunctionSet::Factory /// \param CurrentInliningSet the set of functions currently being inlined in /// the current call stack of recursive calls /// /// \returns true if successful, false if failed due to circular inlining. static bool runOnFunctionRecursively(SILOptFunctionBuilder &FuncBuilder, SILFunction *F, FullApplySite AI, DenseFunctionSet &FullyInlinedSet, ImmutableFunctionSet::Factory &SetFactory, ImmutableFunctionSet CurrentInliningSet, ClassHierarchyAnalysis *CHA) { // Avoid reprocessing functions needlessly. if (FullyInlinedSet.count(F)) return true; // Prevent attempt to circularly inline. if (CurrentInliningSet.contains(F)) { // This cannot happen on a top-level call, so AI should be non-null. assert(AI && "Cannot have circular inline without apply"); SILLocation L = AI.getLoc(); assert(L && "Must have location for transparent inline apply"); diagnose(F->getModule().getASTContext(), L.getStartSourceLoc(), diag::circular_transparent); return false; } // Add to the current inlining set (immutably, so we only affect the set // during this call and recursive subcalls). CurrentInliningSet = SetFactory.add(CurrentInliningSet, F); SmallVector<std::pair<SILValue, ParameterConvention>, 16> CaptureArgs; SmallVector<SILValue, 32> FullArgs; // Visiting blocks in reverse order avoids revisiting instructions after block // splitting, which would be quadratic. for (auto BI = F->rbegin(), BE = F->rend(), nextBB = BI; BI != BE; BI = nextBB) { // After inlining, the block iterator will be adjusted to point to the last // block containing inlined instructions. This way, the inlined function // body will be reprocessed within the caller's context without revisiting // any original instructions. nextBB = std::next(BI); // While iterating over this block, instructions are inserted and deleted. // To avoid quadratic block splitting, instructions must be processed in // reverse order (block splitting reassigned the parent pointer of all // instructions below the split point). for (auto II = BI->rbegin(); II != BI->rend(); ++II) { FullApplySite InnerAI = FullApplySite::isa(&*II); if (!InnerAI) continue; // *NOTE* If devirtualization succeeds, devirtInst may not be InnerAI, // but a casted result of InnerAI or even a block argument due to // abstraction changes when calling the witness or class method. auto *devirtInst = tryDevirtualizeApplyHelper(InnerAI, CHA); // Restore II to the current apply site. II = devirtInst->getReverseIterator(); // If the devirtualized call result is no longer a invalid FullApplySite, // then it has succeeded, but the result is not immediately inlinable. InnerAI = FullApplySite::isa(devirtInst); if (!InnerAI) continue; SILValue CalleeValue = InnerAI.getCallee(); bool IsThick; PartialApplyInst *PAI; SILFunction *CalleeFunction = getCalleeFunction( F, InnerAI, IsThick, CaptureArgs, FullArgs, PAI); if (!CalleeFunction) continue; // Then recursively process it first before trying to inline it. if (!runOnFunctionRecursively(FuncBuilder, CalleeFunction, InnerAI, FullyInlinedSet, SetFactory, CurrentInliningSet, CHA)) { // If we failed due to circular inlining, then emit some notes to // trace back the failure if we have more information. // FIXME: possibly it could be worth recovering and attempting other // inlines within this same recursive call rather than simply // propagating the failure. if (AI) { SILLocation L = AI.getLoc(); assert(L && "Must have location for transparent inline apply"); diagnose(F->getModule().getASTContext(), L.getStartSourceLoc(), diag::note_while_inlining); } return false; } // Get our list of substitutions. auto Subs = (PAI ? PAI->getSubstitutionMap() : InnerAI.getSubstitutionMap()); SILOpenedArchetypesTracker OpenedArchetypesTracker(F); F->getModule().registerDeleteNotificationHandler( &OpenedArchetypesTracker); // The callee only needs to know about opened archetypes used in // the substitution list. OpenedArchetypesTracker.registerUsedOpenedArchetypes( InnerAI.getInstruction()); if (PAI) { OpenedArchetypesTracker.registerUsedOpenedArchetypes(PAI); } SILInliner Inliner(FuncBuilder, SILInliner::InlineKind::MandatoryInline, Subs, OpenedArchetypesTracker); if (!Inliner.canInlineApplySite(InnerAI)) continue; // Inline function at I, which also changes I to refer to the first // instruction inlined in the case that it succeeds. We purposely // process the inlined body after inlining, because the inlining may // have exposed new inlining opportunities beyond those present in // the inlined function when processed independently. LLVM_DEBUG(llvm::errs() << "Inlining @" << CalleeFunction->getName() << " into @" << InnerAI.getFunction()->getName() << "\n"); // If we intend to inline a thick function, then we need to balance the // reference counts for correctness. if (IsThick) { bool IsCalleeGuaranteed = PAI && PAI->getType().castTo<SILFunctionType>()->isCalleeGuaranteed(); fixupReferenceCounts(InnerAI.getInstruction(), CalleeValue, CaptureArgs, IsCalleeGuaranteed); } // Register a callback to record potentially unused function values after // inlining. ClosureCleanup closureCleanup; Inliner.setDeletionCallback([&closureCleanup](SILInstruction *I) { closureCleanup.recordDeadFunction(I); }); // Inlining deletes the apply, and can introduce multiple new basic // blocks. After this, CalleeValue and other instructions may be invalid. // nextBB will point to the last inlined block auto firstInlinedInstAndLastBB = Inliner.inlineFunction(CalleeFunction, InnerAI, FullArgs); nextBB = firstInlinedInstAndLastBB.second->getReverseIterator(); ++NumMandatoryInlines; // The IR is now valid, and trivial dead arguments are removed. However, // we may be able to remove dead callee computations (e.g. dead // partial_apply closures). closureCleanup.cleanupDeadClosures(F); // Resume inlining within nextBB, which contains only the inlined // instructions and possibly instructions in the original call block that // have not yet been visited. break; } } // Keep track of full inlined functions so we don't waste time recursively // reprocessing them. FullyInlinedSet.insert(F); return true; }
/// \brief Inlines all mandatory inlined functions into the body of a function, /// first recursively inlining all mandatory apply instructions in those /// functions into their bodies if necessary. /// /// \param F the function to be processed /// \param AI nullptr if this is being called from the top level; the relevant /// ApplyInst requiring the recursive call when non-null /// \param FullyInlinedSet the set of all functions already known to be fully /// processed, to avoid processing them over again /// \param SetFactory an instance of ImmutableFunctionSet::Factory /// \param CurrentInliningSet the set of functions currently being inlined in /// the current call stack of recursive calls /// /// \returns true if successful, false if failed due to circular inlining. static bool runOnFunctionRecursively(SILFunction *F, FullApplySite AI, DenseFunctionSet &FullyInlinedSet, ImmutableFunctionSet::Factory &SetFactory, ImmutableFunctionSet CurrentInliningSet, ClassHierarchyAnalysis *CHA) { // Avoid reprocessing functions needlessly. if (FullyInlinedSet.count(F)) return true; // Prevent attempt to circularly inline. if (CurrentInliningSet.contains(F)) { // This cannot happen on a top-level call, so AI should be non-null. assert(AI && "Cannot have circular inline without apply"); SILLocation L = AI.getLoc(); assert(L && "Must have location for transparent inline apply"); diagnose(F->getModule().getASTContext(), L.getStartSourceLoc(), diag::circular_transparent); return false; } // Add to the current inlining set (immutably, so we only affect the set // during this call and recursive subcalls). CurrentInliningSet = SetFactory.add(CurrentInliningSet, F); SmallVector<std::pair<SILValue, ParameterConvention>, 16> CaptureArgs; SmallVector<SILValue, 32> FullArgs; for (auto BI = F->begin(), BE = F->end(); BI != BE; ++BI) { for (auto II = BI->begin(), IE = BI->end(); II != IE; ++II) { FullApplySite InnerAI = FullApplySite::isa(&*II); if (!InnerAI) continue; auto *ApplyBlock = InnerAI.getParent(); // *NOTE* If devirtualization succeeds, sometimes II will not be InnerAI, // but a casted result of InnerAI or even a block argument due to // abstraction changes when calling the witness or class method. We still // know that InnerAI dominates II though. std::tie(InnerAI, II) = tryDevirtualizeApplyHelper(InnerAI, II, CHA); if (!InnerAI) continue; SILValue CalleeValue = InnerAI.getCallee(); bool IsThick; PartialApplyInst *PAI; SILFunction *CalleeFunction = getCalleeFunction( F, InnerAI, IsThick, CaptureArgs, FullArgs, PAI); if (!CalleeFunction) continue; // Then recursively process it first before trying to inline it. if (!runOnFunctionRecursively(CalleeFunction, InnerAI, FullyInlinedSet, SetFactory, CurrentInliningSet, CHA)) { // If we failed due to circular inlining, then emit some notes to // trace back the failure if we have more information. // FIXME: possibly it could be worth recovering and attempting other // inlines within this same recursive call rather than simply // propagating the failure. if (AI) { SILLocation L = AI.getLoc(); assert(L && "Must have location for transparent inline apply"); diagnose(F->getModule().getASTContext(), L.getStartSourceLoc(), diag::note_while_inlining); } return false; } // Get our list of substitutions. auto Subs = (PAI ? PAI->getSubstitutionMap() : InnerAI.getSubstitutionMap()); SILOpenedArchetypesTracker OpenedArchetypesTracker(F); F->getModule().registerDeleteNotificationHandler( &OpenedArchetypesTracker); // The callee only needs to know about opened archetypes used in // the substitution list. OpenedArchetypesTracker.registerUsedOpenedArchetypes( InnerAI.getInstruction()); if (PAI) { OpenedArchetypesTracker.registerUsedOpenedArchetypes(PAI); } SILInliner Inliner(*F, *CalleeFunction, SILInliner::InlineKind::MandatoryInline, Subs, OpenedArchetypesTracker); if (!Inliner.canInlineFunction(InnerAI)) { // See comment above about casting when devirtualizing and how this // sometimes causes II and InnerAI to be different and even in different // blocks. II = InnerAI.getInstruction()->getIterator(); continue; } // Inline function at I, which also changes I to refer to the first // instruction inlined in the case that it succeeds. We purposely // process the inlined body after inlining, because the inlining may // have exposed new inlining opportunities beyond those present in // the inlined function when processed independently. LLVM_DEBUG(llvm::errs() << "Inlining @" << CalleeFunction->getName() << " into @" << InnerAI.getFunction()->getName() << "\n"); // If we intend to inline a thick function, then we need to balance the // reference counts for correctness. if (IsThick) { bool IsCalleeGuaranteed = PAI && PAI->getType().castTo<SILFunctionType>()->isCalleeGuaranteed(); fixupReferenceCounts(II, CalleeValue, CaptureArgs, IsCalleeGuaranteed); } // Decrement our iterator (carefully, to avoid going off the front) so it // is valid after inlining is done. Inlining deletes the apply, and can // introduce multiple new basic blocks. II = prev_or_default(II, ApplyBlock->begin(), ApplyBlock->end()); Inliner.inlineFunction(InnerAI, FullArgs); // We were able to inline successfully. Remove the apply. InnerAI.getInstruction()->eraseFromParent(); // Reestablish our iterator if it wrapped. if (II == ApplyBlock->end()) II = ApplyBlock->begin(); // Update the iterator when instructions are removed. DeleteInstructionsHandler DeletionHandler(II); // Now that the IR is correct, see if we can remove dead callee // computations (e.g. dead partial_apply closures). cleanupCalleeValue(CalleeValue, FullArgs); // Reposition iterators possibly invalidated by mutation. BI = SILFunction::iterator(ApplyBlock); IE = ApplyBlock->end(); assert(BI == SILFunction::iterator(II->getParent()) && "Mismatch between the instruction and basic block"); ++NumMandatoryInlines; } } // Keep track of full inlined functions so we don't waste time recursively // reprocessing them. FullyInlinedSet.insert(F); return true; }
/// \brief Inlines all mandatory inlined functions into the body of a function, /// first recursively inlining all mandatory apply instructions in those /// functions into their bodies if necessary. /// /// \param F the function to be processed /// \param AI nullptr if this is being called from the top level; the relevant /// ApplyInst requiring the recursive call when non-null /// \param FullyInlinedSet the set of all functions already known to be fully /// processed, to avoid processing them over again /// \param SetFactory an instance of ImmutableFunctionSet::Factory /// \param CurrentInliningSet the set of functions currently being inlined in /// the current call stack of recursive calls /// /// \returns true if successful, false if failed due to circular inlining. static bool runOnFunctionRecursively(SILFunction *F, FullApplySite AI, SILModule::LinkingMode Mode, DenseFunctionSet &FullyInlinedSet, ImmutableFunctionSet::Factory &SetFactory, ImmutableFunctionSet CurrentInliningSet, ClassHierarchyAnalysis *CHA) { // Avoid reprocessing functions needlessly. if (FullyInlinedSet.count(F)) return true; // Prevent attempt to circularly inline. if (CurrentInliningSet.contains(F)) { // This cannot happen on a top-level call, so AI should be non-null. assert(AI && "Cannot have circular inline without apply"); SILLocation L = AI.getLoc(); assert(L && "Must have location for transparent inline apply"); diagnose(F->getModule().getASTContext(), L.getStartSourceLoc(), diag::circular_transparent); return false; } // Add to the current inlining set (immutably, so we only affect the set // during this call and recursive subcalls). CurrentInliningSet = SetFactory.add(CurrentInliningSet, F); SmallVector<SILValue, 16> CaptureArgs; SmallVector<SILValue, 32> FullArgs; for (auto FI = F->begin(), FE = F->end(); FI != FE; ++FI) { for (auto I = FI->begin(), E = FI->end(); I != E; ++I) { FullApplySite InnerAI = FullApplySite::isa(&*I); if (!InnerAI) continue; auto *ApplyBlock = InnerAI.getParent(); auto NewInstPair = tryDevirtualizeApply(InnerAI, CHA); if (auto *NewInst = NewInstPair.first) { replaceDeadApply(InnerAI, NewInst); if (auto *II = dyn_cast<SILInstruction>(NewInst)) I = II->getIterator(); else I = NewInst->getParentBB()->begin(); auto NewAI = FullApplySite::isa(NewInstPair.second.getInstruction()); if (!NewAI) continue; InnerAI = NewAI; } SILLocation Loc = InnerAI.getLoc(); SILValue CalleeValue = InnerAI.getCallee(); bool IsThick; PartialApplyInst *PAI; SILFunction *CalleeFunction = getCalleeFunction(InnerAI, IsThick, CaptureArgs, FullArgs, PAI, Mode); if (!CalleeFunction || CalleeFunction->isTransparent() == IsNotTransparent) continue; // Then recursively process it first before trying to inline it. if (!runOnFunctionRecursively(CalleeFunction, InnerAI, Mode, FullyInlinedSet, SetFactory, CurrentInliningSet, CHA)) { // If we failed due to circular inlining, then emit some notes to // trace back the failure if we have more information. // FIXME: possibly it could be worth recovering and attempting other // inlines within this same recursive call rather than simply // propagating the failure. if (AI) { SILLocation L = AI.getLoc(); assert(L && "Must have location for transparent inline apply"); diagnose(F->getModule().getASTContext(), L.getStartSourceLoc(), diag::note_while_inlining); } return false; } // Inline function at I, which also changes I to refer to the first // instruction inlined in the case that it succeeds. We purposely // process the inlined body after inlining, because the inlining may // have exposed new inlining opportunities beyond those present in // the inlined function when processed independently. DEBUG(llvm::errs() << "Inlining @" << CalleeFunction->getName() << " into @" << InnerAI.getFunction()->getName() << "\n"); // Decrement our iterator (carefully, to avoid going off the front) so it // is valid after inlining is done. Inlining deletes the apply, and can // introduce multiple new basic blocks. if (I != ApplyBlock->begin()) --I; else I = ApplyBlock->end(); TypeSubstitutionMap ContextSubs; std::vector<Substitution> ApplySubs(InnerAI.getSubstitutions()); if (PAI) { auto PAISubs = PAI->getSubstitutions(); ApplySubs.insert(ApplySubs.end(), PAISubs.begin(), PAISubs.end()); } ContextSubs.copyFrom(CalleeFunction->getContextGenericParams() ->getSubstitutionMap(ApplySubs)); SILInliner Inliner(*F, *CalleeFunction, SILInliner::InlineKind::MandatoryInline, ContextSubs, ApplySubs); if (!Inliner.inlineFunction(InnerAI, FullArgs)) { I = InnerAI.getInstruction()->getIterator(); continue; } // Inlining was successful. Remove the apply. InnerAI.getInstruction()->eraseFromParent(); // Reestablish our iterator if it wrapped. if (I == ApplyBlock->end()) I = ApplyBlock->begin(); else ++I; // If the inlined apply was a thick function, then we need to balance the // reference counts for correctness. if (IsThick) fixupReferenceCounts(I, Loc, CalleeValue, CaptureArgs); // Now that the IR is correct, see if we can remove dead callee // computations (e.g. dead partial_apply closures). cleanupCalleeValue(CalleeValue, CaptureArgs, FullArgs); // Reposition iterators possibly invalidated by mutation. FI = SILFunction::iterator(ApplyBlock); I = ApplyBlock->begin(); E = ApplyBlock->end(); ++NumMandatoryInlines; } } // Keep track of full inlined functions so we don't waste time recursively // reprocessing them. FullyInlinedSet.insert(F); return true; }
/// \brief Inlines all mandatory inlined functions into the body of a function, /// first recursively inlining all mandatory apply instructions in those /// functions into their bodies if necessary. /// /// \param F the function to be processed /// \param AI nullptr if this is being called from the top level; the relevant /// ApplyInst requiring the recursive call when non-null /// \param FullyInlinedSet the set of all functions already known to be fully /// processed, to avoid processing them over again /// \param SetFactory an instance of ImmutableFunctionSet::Factory /// \param CurrentInliningSet the set of functions currently being inlined in /// the current call stack of recursive calls /// /// \returns true if successful, false if failed due to circular inlining. static bool runOnFunctionRecursively(SILFunction *F, FullApplySite AI, SILModule::LinkingMode Mode, DenseFunctionSet &FullyInlinedSet, ImmutableFunctionSet::Factory &SetFactory, ImmutableFunctionSet CurrentInliningSet, ClassHierarchyAnalysis *CHA) { // Avoid reprocessing functions needlessly. if (FullyInlinedSet.count(F)) return true; // Prevent attempt to circularly inline. if (CurrentInliningSet.contains(F)) { // This cannot happen on a top-level call, so AI should be non-null. assert(AI && "Cannot have circular inline without apply"); SILLocation L = AI.getLoc(); assert(L && "Must have location for transparent inline apply"); diagnose(F->getModule().getASTContext(), L.getStartSourceLoc(), diag::circular_transparent); return false; } // Add to the current inlining set (immutably, so we only affect the set // during this call and recursive subcalls). CurrentInliningSet = SetFactory.add(CurrentInliningSet, F); SmallVector<SILValue, 16> CaptureArgs; SmallVector<SILValue, 32> FullArgs; for (auto FI = F->begin(), FE = F->end(); FI != FE; ++FI) { for (auto I = FI->begin(), E = FI->end(); I != E; ++I) { FullApplySite InnerAI = FullApplySite::isa(&*I); if (!InnerAI) continue; auto *ApplyBlock = InnerAI.getParent(); auto NewInstPair = tryDevirtualizeApply(InnerAI, CHA); if (auto *NewInst = NewInstPair.first) { replaceDeadApply(InnerAI, NewInst); if (auto *II = dyn_cast<SILInstruction>(NewInst)) I = II->getIterator(); else I = NewInst->getParentBlock()->begin(); auto NewAI = FullApplySite::isa(NewInstPair.second.getInstruction()); if (!NewAI) continue; InnerAI = NewAI; } SILLocation Loc = InnerAI.getLoc(); SILValue CalleeValue = InnerAI.getCallee(); bool IsThick; PartialApplyInst *PAI; SILFunction *CalleeFunction = getCalleeFunction(InnerAI, IsThick, CaptureArgs, FullArgs, PAI, Mode); if (!CalleeFunction || CalleeFunction->isTransparent() == IsNotTransparent) continue; if (F->isFragile() && !CalleeFunction->hasValidLinkageForFragileRef()) { if (!CalleeFunction->hasValidLinkageForFragileInline()) { llvm::errs() << "caller: " << F->getName() << "\n"; llvm::errs() << "callee: " << CalleeFunction->getName() << "\n"; llvm_unreachable("Should never be inlining a resilient function into " "a fragile function"); } continue; } // Then recursively process it first before trying to inline it. if (!runOnFunctionRecursively(CalleeFunction, InnerAI, Mode, FullyInlinedSet, SetFactory, CurrentInliningSet, CHA)) { // If we failed due to circular inlining, then emit some notes to // trace back the failure if we have more information. // FIXME: possibly it could be worth recovering and attempting other // inlines within this same recursive call rather than simply // propagating the failure. if (AI) { SILLocation L = AI.getLoc(); assert(L && "Must have location for transparent inline apply"); diagnose(F->getModule().getASTContext(), L.getStartSourceLoc(), diag::note_while_inlining); } return false; } // Inline function at I, which also changes I to refer to the first // instruction inlined in the case that it succeeds. We purposely // process the inlined body after inlining, because the inlining may // have exposed new inlining opportunities beyond those present in // the inlined function when processed independently. DEBUG(llvm::errs() << "Inlining @" << CalleeFunction->getName() << " into @" << InnerAI.getFunction()->getName() << "\n"); // If we intend to inline a thick function, then we need to balance the // reference counts for correctness. if (IsThick && I != ApplyBlock->begin()) { // We need to find an appropriate location for our fix up code // We used to do this after inlining Without any modifications // This caused us to add a release in a wrong place: // It would release a value *before* retaining it! // It is really problematic to do this after inlining - // Finding a valid insertion point is tricky: // Inlining might add new basic blocks and/or remove the apply // We want to add the fix up *just before* where the current apply is! // Unfortunately, we *can't* add the fix up code here: // Inlining might fail for any reason - // If that occurred we'd need to undo our fix up code. // Instead, we split the current basic block - // Making sure we have a basic block that starts with our apply. SILBuilderWithScope B(I); ApplyBlock = splitBasicBlockAndBranch(B, &*I, nullptr, nullptr); I = ApplyBlock->begin(); } // Decrement our iterator (carefully, to avoid going off the front) so it // is valid after inlining is done. Inlining deletes the apply, and can // introduce multiple new basic blocks. if (I != ApplyBlock->begin()) --I; else I = ApplyBlock->end(); std::vector<Substitution> ApplySubs(InnerAI.getSubstitutions()); if (PAI) { auto PAISubs = PAI->getSubstitutions(); ApplySubs.insert(ApplySubs.end(), PAISubs.begin(), PAISubs.end()); } SILOpenedArchetypesTracker OpenedArchetypesTracker(*F); F->getModule().registerDeleteNotificationHandler( &OpenedArchetypesTracker); // The callee only needs to know about opened archetypes used in // the substitution list. OpenedArchetypesTracker.registerUsedOpenedArchetypes(InnerAI.getInstruction()); if (PAI) { OpenedArchetypesTracker.registerUsedOpenedArchetypes(PAI); } SILInliner Inliner(*F, *CalleeFunction, SILInliner::InlineKind::MandatoryInline, ApplySubs, OpenedArchetypesTracker); if (!Inliner.inlineFunction(InnerAI, FullArgs)) { I = InnerAI.getInstruction()->getIterator(); continue; } // Inlining was successful. Remove the apply. InnerAI.getInstruction()->eraseFromParent(); // Reestablish our iterator if it wrapped. if (I == ApplyBlock->end()) I = ApplyBlock->begin(); // Update the iterator when instructions are removed. DeleteInstructionsHandler DeletionHandler(I); // If the inlined apply was a thick function, then we need to balance the // reference counts for correctness. if (IsThick) fixupReferenceCounts(I, Loc, CalleeValue, CaptureArgs); // Now that the IR is correct, see if we can remove dead callee // computations (e.g. dead partial_apply closures). cleanupCalleeValue(CalleeValue, CaptureArgs, FullArgs); // Reposition iterators possibly invalidated by mutation. FI = SILFunction::iterator(ApplyBlock); E = ApplyBlock->end(); assert(FI == SILFunction::iterator(I->getParent()) && "Mismatch between the instruction and basic block"); ++NumMandatoryInlines; } } // Keep track of full inlined functions so we don't waste time recursively // reprocessing them. FullyInlinedSet.insert(F); return true; }