Exemplo n.º 1
0
void
FunctionSignatureSpecializationMangler::mangleConstantProp(LiteralInst *LI) {
  // Append the prefix for constant propagation 'p'.
  ArgOpBuffer << 'p';

  // Then append the unique identifier of our literal.
  switch (LI->getKind()) {
  default:
    llvm_unreachable("unknown literal");
  case SILInstructionKind::DynamicFunctionRefInst: {
    SILFunction *F = cast<DynamicFunctionRefInst>(LI)->getReferencedFunction();
    ArgOpBuffer << 'f';
    appendIdentifier(F->getName());
    break;
  }
  case SILInstructionKind::FunctionRefInst: {
    SILFunction *F = cast<FunctionRefInst>(LI)->getReferencedFunction();
    ArgOpBuffer << 'f';
    appendIdentifier(F->getName());
    break;
  }
  case SILInstructionKind::GlobalAddrInst: {
    SILGlobalVariable *G = cast<GlobalAddrInst>(LI)->getReferencedGlobal();
    ArgOpBuffer << 'g';
    appendIdentifier(G->getName());
    break;
  }
  case SILInstructionKind::IntegerLiteralInst: {
    APInt apint = cast<IntegerLiteralInst>(LI)->getValue();
    ArgOpBuffer << 'i' << apint;
    break;
  }
  case SILInstructionKind::FloatLiteralInst: {
    APInt apint = cast<FloatLiteralInst>(LI)->getBits();
    ArgOpBuffer << 'd' << apint;
    break;
  }
  case SILInstructionKind::StringLiteralInst: {
    StringLiteralInst *SLI = cast<StringLiteralInst>(LI);
    StringRef V = SLI->getValue();
    assert(V.size() <= 32 && "Cannot encode string of length > 32");
    std::string VBuffer;
    if (!V.empty() && (isDigit(V[0]) || V[0] == '_')) {
      VBuffer = "_";
      VBuffer.append(V.data(), V.size());
      V = VBuffer;
    }
    appendIdentifier(V);

    ArgOpBuffer << 's';
    switch (SLI->getEncoding()) {
      case StringLiteralInst::Encoding::Bytes: ArgOpBuffer << 'B'; break;
      case StringLiteralInst::Encoding::UTF8: ArgOpBuffer << 'b'; break;
      case StringLiteralInst::Encoding::UTF16: ArgOpBuffer << 'w'; break;
      case StringLiteralInst::Encoding::ObjCSelector: ArgOpBuffer << 'c'; break;
    }
    break;
  }
  }
}
Exemplo n.º 2
0
static bool processFunctionWithLoopSupport(
    SILFunction &F, AliasAnalysis *AA, PostOrderAnalysis *POTA,
    LoopRegionFunctionInfo *LRFI, SILLoopInfo *LI, RCIdentityFunctionInfo *RCFI,
    ProgramTerminationFunctionInfo *PTFI) {
  // GlobalARCOpts seems to be taking up a lot of compile time when running on
  // globalinit_func. Since that is not *that* interesting from an ARC
  // perspective (i.e. no ref count operations in a loop), disable it on such
  // functions temporarily in order to unblock others. This should be removed.
  if (F.getName().startswith("globalinit_"))
    return false;

  DEBUG(llvm::dbgs() << "***** Processing " << F.getName() << " *****\n");

  LoopARCPairingContext Context(F, AA, LRFI, LI, RCFI, PTFI);
  return Context.process();
}
Exemplo n.º 3
0
 std::string getNodeLabel(const OrderedCallGraph::Node *Node,
                          const OrderedCallGraph *Graph) {
   SILFunction *F = Node->CGNode->getFunction();
   std::string Label = F->getName();
   wrap(Label, Node->NumCallSites);
   return Label;
 }
Exemplo n.º 4
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// Update UnhandledOnceCallee and InitializerCount by going through all "once"
// calls.
void SILGlobalOpt::collectOnceCall(BuiltinInst *BI) {
  if (UnhandledOnceCallee)
    return;

  const BuiltinInfo &Builtin = Module->getBuiltinInfo(BI->getName());
  if (Builtin.ID != BuiltinValueKind::Once)
    return;

  SILFunction *Callee = getCalleeOfOnceCall(BI);
  if (!Callee) {
    LLVM_DEBUG(llvm::dbgs() << "GlobalOpt: unhandled once callee\n");
    UnhandledOnceCallee = true;
    return;
  }
  if (!Callee->getName().startswith("globalinit_"))
    return;

  // We currently disable optimizing the initializer if a globalinit_func
  // is called by "once" from multiple locations.
  if (!BI->getFunction()->isGlobalInit())
    // If a globalinit_func is called by "once" from a function that is not
    // an addressor, we set count to 2 to disable optimizing the initializer.
    InitializerCount[Callee] = 2;
  else
    InitializerCount[Callee]++;
}
Exemplo n.º 5
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 std::string getNodeDescription(const OrderedCallGraph::Node *Node,
                          const OrderedCallGraph *Graph) {
   SILFunction *F = Node->CGNode->getFunction();
   std::string Label = demangle_wrappers::
                       demangleSymbolAsString(F->getName());
   wrap(Label, Node->NumCallSites);
   return Label;
 }
Exemplo n.º 6
0
static bool
processFunctionWithoutLoopSupport(SILFunction &F, bool FreezePostDomReleases,
                                  AliasAnalysis *AA, PostOrderAnalysis *POTA,
                                  RCIdentityFunctionInfo *RCIA,
                                  EpilogueARCFunctionInfo *EAFI,
                                  ProgramTerminationFunctionInfo *PTFI) {
  // GlobalARCOpts seems to be taking up a lot of compile time when running on
  // globalinit_func. Since that is not *that* interesting from an ARC
  // perspective (i.e. no ref count operations in a loop), disable it on such
  // functions temporarily in order to unblock others. This should be removed.
  if (F.getName().startswith("globalinit_"))
    return false;

  LLVM_DEBUG(llvm::dbgs() << "***** Processing " << F.getName() << " *****\n");

  bool Changed = false;
  BlockARCPairingContext Context(F, AA, POTA, RCIA, EAFI, PTFI);
  // Until we do not remove any instructions or have nested increments,
  // decrements...
  while (true) {
    // Compute matching sets of increments, decrements, and their insertion
    // points.
    //
    // We need to blot pointers we remove after processing an individual pointer
    // so we don't process pairs after we have paired them up. Thus we pass in a
    // lambda that performs the work for us.
    bool ShouldRunAgain = Context.run(FreezePostDomReleases);

    Changed |= Context.madeChange();

    // If we did not remove any instructions or have any nested increments, do
    // not perform another iteration.
    if (!ShouldRunAgain)
      break;

    // Otherwise, perform another iteration.
    LLVM_DEBUG(llvm::dbgs() << "\n<<< Made a Change! "
                               "Reprocessing Function! >>>\n");
  }

  LLVM_DEBUG(llvm::dbgs() << "\n");

  // Return true if we moved or deleted any instructions.
  return Changed;
}
Exemplo n.º 7
0
/// \brief Attempt to inline all calls smaller than our threshold.
/// returns True if a function was inlined.
bool SILPerformanceInliner::inlineCallsIntoFunction(SILFunction *Caller,
                                                    DominanceAnalysis *DA,
                                                    SILLoopAnalysis *LA) {
  // Don't optimize functions that are marked with the opt.never attribute.
  if (!Caller->shouldOptimize())
    return false;

  DEBUG(llvm::dbgs() << "Visiting Function: " << Caller->getName() << "\n");

  // First step: collect all the functions we want to inline.  We
  // don't change anything yet so that the dominator information
  // remains valid.
  SmallVector<FullApplySite, 8> AppliesToInline;
  collectAppliesToInline(Caller, AppliesToInline, DA, LA);

  if (AppliesToInline.empty())
    return false;

  // Second step: do the actual inlining.
  for (auto AI : AppliesToInline) {
    SILFunction *Callee = AI.getCalleeFunction();
    assert(Callee && "apply_inst does not have a direct callee anymore");

    DEBUG(llvm::dbgs() << "    Inline:" <<  *AI.getInstruction());

    if (!Callee->shouldOptimize()) {
      DEBUG(llvm::dbgs() << "    Cannot inline function " << Callee->getName()
                         << " marked to be excluded from optimizations.\n");
      continue;
    }
    
    SmallVector<SILValue, 8> Args;
    for (const auto &Arg : AI.getArguments())
      Args.push_back(Arg);

    // Notice that we will skip all of the newly inlined ApplyInsts. That's
    // okay because we will visit them in our next invocation of the inliner.
    TypeSubstitutionMap ContextSubs;
    SILInliner Inliner(*Caller, *Callee,
                       SILInliner::InlineKind::PerformanceInline, ContextSubs,
                       AI.getSubstitutions());

    auto Success = Inliner.inlineFunction(AI, Args);
    (void) Success;
    // We've already determined we should be able to inline this, so
    // we expect it to have happened.
    assert(Success && "Expected inliner to inline this function!");

    recursivelyDeleteTriviallyDeadInstructions(AI.getInstruction(), true);

    NumFunctionsInlined++;
  }

  DEBUG(llvm::dbgs() << "\n");
  return true;
}
Exemplo n.º 8
0
void
FunctionSignatureSpecializationMangler::mangleConstantProp(LiteralInst *LI) {
  Mangler &M = getMangler();

  // Append the prefix for constant propagation 'cp'.
  M.append("cp");

  // Then append the unique identifier of our literal.
  switch (LI->getKind()) {
  default:
    llvm_unreachable("unknown literal");
  case ValueKind::FunctionRefInst: {
    SILFunction *F = cast<FunctionRefInst>(LI)->getReferencedFunction();
    M.append("fr");
    M.mangleIdentifierSymbol(F->getName());
    break;
  }
  case ValueKind::GlobalAddrInst: {
    SILGlobalVariable *G = cast<GlobalAddrInst>(LI)->getReferencedGlobal();
    M.append("g");
    M.mangleIdentifierSymbol(G->getName());
    break;
  }
  case ValueKind::IntegerLiteralInst: {
    APInt apint = cast<IntegerLiteralInst>(LI)->getValue();
    M.append("i");
    M.mangleNatural(apint);
    break;
  }
  case ValueKind::FloatLiteralInst: {
    APInt apint = cast<FloatLiteralInst>(LI)->getBits();
    M.append("fl");
    M.mangleNatural(apint);
    break;
  }
  case ValueKind::StringLiteralInst: {
    StringLiteralInst *SLI = cast<StringLiteralInst>(LI);
    StringRef V = SLI->getValue();

    assert(V.size() <= 32 && "Cannot encode string of length > 32");

    llvm::SmallString<33> Str;
    Str += "u";
    Str += V;
    M.append("se");
    M.mangleNatural(APInt(32, unsigned(SLI->getEncoding())));
    M.append("v");
    M.mangleIdentifier(Str);
    break;
  }
  }
}
Exemplo n.º 9
0
/// \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;
}
Exemplo n.º 10
0
bool SILCombiner::doOneIteration(SILFunction &F, unsigned Iteration) {
  MadeChange = false;

  DEBUG(llvm::dbgs() << "\n\nSILCOMBINE ITERATION #" << Iteration << " on "
                     << F.getName() << "\n");

  // Add reachable instructions to our worklist.
  addReachableCodeToWorklist(&*F.begin());

  // Process until we run out of items in our worklist.
  while (!Worklist.isEmpty()) {
    SILInstruction *I = Worklist.removeOne();

    // When we erase an instruction, we use the map in the worklist to check if
    // the instruction is in the worklist. If it is, we replace it with null
    // instead of shifting all members of the worklist towards the front. This
    // check makes sure that if we run into any such residual null pointers, we
    // skip them.
    if (I == nullptr)
      continue;

    // Check to see if we can DCE the instruction.
    if (isInstructionTriviallyDead(I)) {
      DEBUG(llvm::dbgs() << "SC: DCE: " << *I << '\n');
      eraseInstFromFunction(*I);
      ++NumDeadInst;
      MadeChange = true;
      continue;
    }

    // Check to see if we can instsimplify the instruction.
    if (SILValue Result = simplifyInstruction(I)) {
      ++NumSimplified;

      DEBUG(llvm::dbgs() << "SC: Simplify Old = " << *I << '\n'
                         << "    New = " << *Result << '\n');

      // Everything uses the new instruction now.
      replaceInstUsesWith(*I, Result);

      // Push the new instruction and any users onto the worklist.
      Worklist.addUsersToWorklist(Result);

      eraseInstFromFunction(*I);
      MadeChange = true;
      continue;
    }

    // If we have reached this point, all attempts to do simple simplifications
    // have failed. Prepare to SILCombine.
    Builder.setInsertionPoint(I);

#ifndef NDEBUG
    std::string OrigI;
#endif
    DEBUG(llvm::raw_string_ostream SS(OrigI); I->print(SS); OrigI = SS.str(););
    DEBUG(llvm::dbgs() << "SC: Visiting: " << OrigI << '\n');

    if (SILInstruction *Result = visit(I)) {
      ++NumCombined;
      // Should we replace the old instruction with a new one?
      if (Result != I) {
        assert(&*std::prev(SILBasicBlock::iterator(I)) == Result &&
              "Expected new instruction inserted before existing instruction!");

        DEBUG(llvm::dbgs() << "SC: Old = " << *I << '\n'
                           << "    New = " << *Result << '\n');

        // Everything uses the new instruction now.
        replaceInstUsesWith(*I, Result);

        // Push the new instruction and any users onto the worklist.
        Worklist.add(Result);
        Worklist.addUsersToWorklist(Result);


        eraseInstFromFunction(*I);
      } else {
        DEBUG(llvm::dbgs() << "SC: Mod = " << OrigI << '\n'
                     << "    New = " << *I << '\n');

        // If the instruction was modified, it's possible that it is now dead.
        // if so, remove it.
        if (isInstructionTriviallyDead(I)) {
          eraseInstFromFunction(*I);
        } else {
          Worklist.add(I);
          Worklist.addUsersToWorklist(I);
        }
      }
      MadeChange = true;
    }

    // Our tracking list has been accumulating instructions created by the
    // SILBuilder during this iteration. Go through the tracking list and add
    // its contents to the worklist and then clear said list in preparation for
    // the next iteration.
    auto &TrackingList = *Builder.getTrackingList();
    for (SILInstruction *I : TrackingList) {
      DEBUG(llvm::dbgs() << "SC: add " << *I <<
            " from tracking list to worklist\n");
      Worklist.add(I);
    }
    TrackingList.clear();
  }
Exemplo n.º 11
0
/// Remove retain/release pairs around builtin "unsafeGuaranteed" instruction
/// sequences.
static bool removeGuaranteedRetainReleasePairs(SILFunction &F,
                                               RCIdentityFunctionInfo &RCIA,
                                               PostDominanceAnalysis *PDA) {
  DEBUG(llvm::dbgs() << "Running on function " << F.getName() << "\n");
  bool Changed = false;

  // Lazily compute post-dominance info only when we really need it.
  PostDominanceInfo *PDI = nullptr;

  for (auto &BB : F) {
    auto It = BB.begin(), End = BB.end();
    llvm::DenseMap<SILValue, SILInstruction *> LastRetain;
    while (It != End) {
      auto *CurInst = &*It;
      ++It;

      // Memorize the last retain.
      if (isa<StrongRetainInst>(CurInst) || isa<RetainValueInst>(CurInst)) {
        LastRetain[RCIA.getRCIdentityRoot(CurInst->getOperand(0))] = CurInst;
        continue;
      }

      // Look for a builtin "unsafeGuaranteed" instruction.
      auto *UnsafeGuaranteedI = dyn_cast<BuiltinInst>(CurInst);
      if (!UnsafeGuaranteedI || !UnsafeGuaranteedI->getBuiltinKind() ||
          *UnsafeGuaranteedI->getBuiltinKind() !=
              BuiltinValueKind::UnsafeGuaranteed)
        continue;

      auto Opd = UnsafeGuaranteedI->getOperand(0);
      auto RCIdOpd = RCIA.getRCIdentityRoot(UnsafeGuaranteedI->getOperand(0));
      if (!LastRetain.count(RCIdOpd)) {
        DEBUG(llvm::dbgs() << "LastRetain failed\n");
        continue;
      }

      // This code is very conservative. Check that there is a matching retain
      // before the unsafeGuaranteed builtin with only retains inbetween.
      auto *LastRetainInst = LastRetain[RCIdOpd];
      auto NextInstIter = std::next(SILBasicBlock::iterator(LastRetainInst));
      while (NextInstIter != BB.end() && &*NextInstIter != CurInst &&
             (isa<RetainValueInst>(*NextInstIter) ||
              isa<StrongRetainInst>(*NextInstIter) ||
              !NextInstIter->mayHaveSideEffects() ||
              isa<DebugValueInst>(*NextInstIter) ||
              isa<DebugValueAddrInst>(*NextInstIter)))
       ++NextInstIter;
      if (&*NextInstIter != CurInst) {
        DEBUG(llvm::dbgs() << "Last retain right before match failed\n");
        continue;
      }

      DEBUG(llvm::dbgs() << "Saw " << *UnsafeGuaranteedI);
      DEBUG(llvm::dbgs() << "  with operand " << *Opd);

      // Match the reference and token result.
      //  %4 = builtin "unsafeGuaranteed"<Foo>(%0 : $Foo)
      //  %5 = tuple_extract %4 : $(Foo, Builtin.Int8), 0
      //  %6 = tuple_extract %4 : $(Foo, Builtin.Int8), 1
      SILInstruction *UnsafeGuaranteedValue;
      SILInstruction *UnsafeGuaranteedToken;
      std::tie(UnsafeGuaranteedValue, UnsafeGuaranteedToken) =
          getSingleUnsafeGuaranteedValueResult(UnsafeGuaranteedI);

      if (!UnsafeGuaranteedValue) {
        DEBUG(llvm::dbgs() << "  no single unsafeGuaranteed value use\n");
        continue;
      }

      // Look for a builtin "unsafeGuaranteedEnd" instruction that uses the
      // token.
      //   builtin "unsafeGuaranteedEnd"(%6 : $Builtin.Int8) : $()
      auto *UnsafeGuaranteedEndI =
          getUnsafeGuaranteedEndUser(UnsafeGuaranteedToken);
      if (!UnsafeGuaranteedEndI) {
        DEBUG(llvm::dbgs() << "  no single unsafeGuaranteedEnd use found\n");
        continue;
      }

      if (!PDI)
        PDI = PDA->get(&F);

      // It needs to post-dominated the end instruction, since we need to remove
      // the release along all paths to exit.
      if (!PDI->properlyDominates(UnsafeGuaranteedEndI, UnsafeGuaranteedI))
        continue;


      // Find the release to match with the unsafeGuaranteedValue.
      auto &UnsafeGuaranteedEndBB = *UnsafeGuaranteedEndI->getParent();
      auto LastRelease = findReleaseToMatchUnsafeGuaranteedValue(
          UnsafeGuaranteedEndI, UnsafeGuaranteedI, UnsafeGuaranteedValue,
          UnsafeGuaranteedEndBB, RCIA);
      if (!LastRelease) {
        DEBUG(llvm::dbgs() << "  no release before/after unsafeGuaranteedEnd found\n");
        continue;
      }

      // Restart iteration before the earliest instruction we remove.
      bool RestartAtBeginningOfBlock = false;
      auto LastRetainIt = SILBasicBlock::iterator(LastRetainInst);
      if (LastRetainIt != BB.begin()) {
        It = std::prev(LastRetainIt);
      } else RestartAtBeginningOfBlock = true;

      // Okay we found a post dominating release. Let's remove the
      // retain/unsafeGuaranteed/release combo.
      //
      LastRetainInst->eraseFromParent();
      LastRelease->eraseFromParent();
      UnsafeGuaranteedEndI->eraseFromParent();
      deleteAllDebugUses(UnsafeGuaranteedValue);
      deleteAllDebugUses(UnsafeGuaranteedToken);
      deleteAllDebugUses(UnsafeGuaranteedI);
      UnsafeGuaranteedValue->replaceAllUsesWith(Opd);
      UnsafeGuaranteedValue->eraseFromParent();
      UnsafeGuaranteedToken->eraseFromParent();
      UnsafeGuaranteedI->replaceAllUsesWith(Opd);
      UnsafeGuaranteedI->eraseFromParent();

      if (RestartAtBeginningOfBlock)
        It = BB.begin();

      Changed = true;
    }
  }
  return Changed;
}
Exemplo n.º 12
0
/// \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;
}
Exemplo n.º 13
0
/// Returns the callee SILFunction called at a call site, in the case
/// that the call is transparent (as in, both that the call is marked
/// with the transparent flag and that callee function is actually transparently
/// determinable from the SIL) or nullptr otherwise. This assumes that the SIL
/// is already in SSA form.
///
/// In the case that a non-null value is returned, FullArgs contains effective
/// argument operands for the callee function.
static SILFunction *getCalleeFunction(
    SILFunction *F, FullApplySite AI, bool &IsThick,
    SmallVectorImpl<std::pair<SILValue, ParameterConvention>> &CaptureArgs,
    SmallVectorImpl<SILValue> &FullArgs, PartialApplyInst *&PartialApply) {
  IsThick = false;
  PartialApply = nullptr;
  CaptureArgs.clear();
  FullArgs.clear();

  for (const auto &Arg : AI.getArguments())
    FullArgs.push_back(Arg);
  SILValue CalleeValue = AI.getCallee();

  if (auto *LI = dyn_cast<LoadInst>(CalleeValue)) {
    // Conservatively only see through alloc_box; we assume this pass is run
    // immediately after SILGen
    auto *PBI = dyn_cast<ProjectBoxInst>(LI->getOperand());
    if (!PBI)
      return nullptr;
    auto *ABI = dyn_cast<AllocBoxInst>(PBI->getOperand());
    if (!ABI)
      return nullptr;
    // Ensure there are no other uses of alloc_box than the project_box and
    // retains, releases.
    for (Operand *ABIUse : ABI->getUses())
      if (ABIUse->getUser() != PBI &&
          !isa<StrongRetainInst>(ABIUse->getUser()) &&
          !isa<StrongReleaseInst>(ABIUse->getUser()))
        return nullptr;

    // Scan forward from the alloc box to find the first store, which
    // (conservatively) must be in the same basic block as the alloc box
    StoreInst *SI = nullptr;
    for (auto I = SILBasicBlock::iterator(ABI), E = I->getParent()->end();
         I != E; ++I) {
      // If we find the load instruction first, then the load is loading from
      // a non-initialized alloc; this shouldn't really happen but I'm not
      // making any assumptions
      if (&*I == LI)
        return nullptr;
      if ((SI = dyn_cast<StoreInst>(I)) && SI->getDest() == PBI) {
        // We found a store that we know dominates the load; now ensure there
        // are no other uses of the project_box except loads.
        for (Operand *PBIUse : PBI->getUses())
          if (PBIUse->getUser() != SI && !isa<LoadInst>(PBIUse->getUser()))
            return nullptr;
        // We can conservatively see through the store
        break;
      }
    }
    if (!SI)
      return nullptr;
    CalleeValue = SI->getSrc();
  }

  // PartialApply/ThinToThick -> ConvertFunction patterns are generated
  // by @noescape closures.
  //
  // FIXME: We don't currently handle mismatched return types, however, this
  // would be a good optimization to handle and would be as simple as inserting
  // a cast.
  auto skipFuncConvert = [](SILValue CalleeValue) {
    // We can also allow a thin @escape to noescape conversion as such:
    // %1 = function_ref @thin_closure_impl : $@convention(thin) () -> ()
    // %2 = convert_function %1 :
    //      $@convention(thin) () -> () to $@convention(thin) @noescape () -> ()
    // %3 = thin_to_thick_function %2 :
    //  $@convention(thin) @noescape () -> () to
    //            $@noescape @callee_guaranteed () -> ()
    // %4 = apply %3() : $@noescape @callee_guaranteed () -> ()
    if (auto *ThinToNoescapeCast = dyn_cast<ConvertFunctionInst>(CalleeValue)) {
      auto FromCalleeTy =
          ThinToNoescapeCast->getOperand()->getType().castTo<SILFunctionType>();
      if (FromCalleeTy->getExtInfo().hasContext())
        return CalleeValue;
      auto ToCalleeTy = ThinToNoescapeCast->getType().castTo<SILFunctionType>();
      auto EscapingCalleeTy = ToCalleeTy->getWithExtInfo(
          ToCalleeTy->getExtInfo().withNoEscape(false));
      if (FromCalleeTy != EscapingCalleeTy)
        return CalleeValue;
      return ThinToNoescapeCast->getOperand();
    }

    auto *CFI = dyn_cast<ConvertEscapeToNoEscapeInst>(CalleeValue);
    if (!CFI)
      return CalleeValue;

    // TODO: Handle argument conversion. All the code in this file needs to be
    // cleaned up and generalized. The argument conversion handling in
    // optimizeApplyOfConvertFunctionInst should apply to any combine
    // involving an apply, not just a specific pattern.
    //
    // For now, just handle conversion that doesn't affect argument types,
    // return types, or throws. We could trivially handle any other
    // representation change, but the only one that doesn't affect the ABI and
    // matters here is @noescape, so just check for that.
    auto FromCalleeTy = CFI->getOperand()->getType().castTo<SILFunctionType>();
    auto ToCalleeTy = CFI->getType().castTo<SILFunctionType>();
    auto EscapingCalleeTy =
      ToCalleeTy->getWithExtInfo(ToCalleeTy->getExtInfo().withNoEscape(false));
    if (FromCalleeTy != EscapingCalleeTy)
      return CalleeValue;

    return CFI->getOperand();
  };

  // Look through a escape to @noescape conversion.
  CalleeValue = skipFuncConvert(CalleeValue);

  // We are allowed to see through exactly one "partial apply" instruction or
  // one "thin to thick function" instructions, since those are the patterns
  // generated when using auto closures.
  if (auto *PAI = dyn_cast<PartialApplyInst>(CalleeValue)) {

    // Collect the applied arguments and their convention.
    collectPartiallyAppliedArguments(PAI, CaptureArgs, FullArgs);

    CalleeValue = PAI->getCallee();
    IsThick = true;
    PartialApply = PAI;
  } else if (auto *TTTFI = dyn_cast<ThinToThickFunctionInst>(CalleeValue)) {
    CalleeValue = TTTFI->getOperand();
    IsThick = true;
  }

  CalleeValue = skipFuncConvert(CalleeValue);

  auto *FRI = dyn_cast<FunctionRefInst>(CalleeValue);
  if (!FRI)
    return nullptr;

  SILFunction *CalleeFunction = FRI->getReferencedFunction();

  switch (CalleeFunction->getRepresentation()) {
  case SILFunctionTypeRepresentation::Thick:
  case SILFunctionTypeRepresentation::Thin:
  case SILFunctionTypeRepresentation::Method:
  case SILFunctionTypeRepresentation::Closure:
  case SILFunctionTypeRepresentation::WitnessMethod:
    break;
    
  case SILFunctionTypeRepresentation::CFunctionPointer:
  case SILFunctionTypeRepresentation::ObjCMethod:
  case SILFunctionTypeRepresentation::Block:
    return nullptr;
  }

  // If the CalleeFunction is a not-transparent definition, we can not process
  // it.
  if (CalleeFunction->isTransparent() == IsNotTransparent)
    return nullptr;

  // If CalleeFunction is a declaration, see if we can load it.
  if (CalleeFunction->empty())
    AI.getModule().loadFunction(CalleeFunction);

  // If we fail to load it, bail.
  if (CalleeFunction->empty())
    return nullptr;

  if (F->isSerialized() &&
      !CalleeFunction->hasValidLinkageForFragileInline()) {
    if (!CalleeFunction->hasValidLinkageForFragileRef()) {
      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");
    }
    return nullptr;
  }

  return CalleeFunction;
}
Exemplo n.º 14
0
// Returns the callee of an apply_inst if it is basically inlineable.
SILFunction *SILPerformanceInliner::getEligibleFunction(FullApplySite AI) {

  SILFunction *Callee = AI.getCalleeFunction();
  
  if (!Callee) {
    DEBUG(llvm::dbgs() << "        FAIL: Cannot find inlineable callee.\n");
    return nullptr;
  }

  // Don't inline functions that are marked with the @_semantics or @effects
  // attribute if the inliner is asked not to inline them.
  if (Callee->hasSemanticsAttrs() || Callee->hasEffectsKind()) {
    if (WhatToInline == InlineSelection::NoSemanticsAndGlobalInit) {
      DEBUG(llvm::dbgs() << "        FAIL: Function " << Callee->getName()
            << " has special semantics or effects attribute.\n");
      return nullptr;
    }
    // The "availability" semantics attribute is treated like global-init.
    if (Callee->hasSemanticsAttrs() &&
        WhatToInline != InlineSelection::Everything &&
        Callee->hasSemanticsAttrThatStartsWith("availability")) {
      return nullptr;
    }
  } else if (Callee->isGlobalInit()) {
    if (WhatToInline != InlineSelection::Everything) {
      DEBUG(llvm::dbgs() << "        FAIL: Function " << Callee->getName()
            << " has the global-init attribute.\n");
      return nullptr;
    }
  }

  // We can't inline external declarations.
  if (Callee->empty() || Callee->isExternalDeclaration()) {
    DEBUG(llvm::dbgs() << "        FAIL: Cannot inline external " <<
          Callee->getName() << ".\n");
    return nullptr;
  }

  // Explicitly disabled inlining.
  if (Callee->getInlineStrategy() == NoInline) {
    DEBUG(llvm::dbgs() << "        FAIL: noinline attribute on " <<
          Callee->getName() << ".\n");
    return nullptr;
  }
  
  if (!Callee->shouldOptimize()) {
    DEBUG(llvm::dbgs() << "        FAIL: optimizations disabled on " <<
          Callee->getName() << ".\n");
    return nullptr;
  }

  // We don't support this yet.
  if (AI.hasSubstitutions()) {
    DEBUG(llvm::dbgs() << "        FAIL: Generic substitutions on " <<
          Callee->getName() << ".\n");
    return nullptr;
  }

  // We don't support inlining a function that binds dynamic self because we
  // have no mechanism to preserve the original function's local self metadata.
  if (computeMayBindDynamicSelf(Callee)) {
    DEBUG(llvm::dbgs() << "        FAIL: Binding dynamic Self in " <<
          Callee->getName() << ".\n");
    return nullptr;
  }

  SILFunction *Caller = AI.getFunction();

  // Detect inlining cycles.
  if (hasInliningCycle(Caller, Callee)) {
    DEBUG(llvm::dbgs() << "        FAIL: Detected a recursion inlining " <<
          Callee->getName() << ".\n");
    return nullptr;
  }

  // A non-fragile function may not be inlined into a fragile function.
  if (Caller->isFragile() && !Callee->isFragile()) {
    DEBUG(llvm::dbgs() << "        FAIL: Can't inline fragile " <<
          Callee->getName() << ".\n");
    return nullptr;
  }

  // Inlining self-recursive functions into other functions can result
  // in excessive code duplication since we run the inliner multiple
  // times in our pipeline
  if (calleeIsSelfRecursive(Callee)) {
    DEBUG(llvm::dbgs() << "        FAIL: Callee is self-recursive in "
                       << Callee->getName() << ".\n");
    return nullptr;
  }

  DEBUG(llvm::dbgs() << "        Eligible callee: " <<
        Callee->getName() << "\n");
  
  return Callee;
}
Exemplo n.º 15
0
/// \brief Attempt to inline all calls smaller than our threshold.
/// returns True if a function was inlined.
bool SILPerformanceInliner::inlineCallsIntoFunction(SILFunction *Caller,
                                                    DominanceAnalysis *DA,
                                                    SILLoopAnalysis *LA,
                             llvm::SmallVectorImpl<FullApplySite> &NewApplies) {
  // Don't optimize functions that are marked with the opt.never attribute.
  if (!Caller->shouldOptimize())
    return false;

  // Construct a log of all of the names of the functions that we've inlined
  // in the current iteration.
  SmallVector<StringRef, 16> InlinedFunctionNames;
  StringRef CallerName = Caller->getName();

  DEBUG(llvm::dbgs() << "Visiting Function: " << CallerName << "\n");

  assert(NewApplies.empty() && "Expected empty vector to store results in!");

  // First step: collect all the functions we want to inline.  We
  // don't change anything yet so that the dominator information
  // remains valid.
  SmallVector<FullApplySite, 8> AppliesToInline;
  collectAppliesToInline(Caller, AppliesToInline, DA, LA);

  if (AppliesToInline.empty())
    return false;

  // Second step: do the actual inlining.
  for (auto AI : AppliesToInline) {
    SILFunction *Callee = AI.getCalleeFunction();
    assert(Callee && "apply_inst does not have a direct callee anymore");

    DEBUG(llvm::dbgs() << "    Inline:" <<  *AI.getInstruction());

    if (!Callee->shouldOptimize()) {
      DEBUG(llvm::dbgs() << "    Cannot inline function " << Callee->getName()
                         << " marked to be excluded from optimizations.\n");
      continue;
    }
    
    SmallVector<SILValue, 8> Args;
    for (const auto &Arg : AI.getArguments())
      Args.push_back(Arg);

    // As we inline and clone we need to collect new applies.
    auto Filter = [](SILInstruction *I) -> bool {
      return bool(FullApplySite::isa(I));
    };

    CloneCollector Collector(Filter);

    // Notice that we will skip all of the newly inlined ApplyInsts. That's
    // okay because we will visit them in our next invocation of the inliner.
    TypeSubstitutionMap ContextSubs;
    SILInliner Inliner(*Caller, *Callee,
                       SILInliner::InlineKind::PerformanceInline,
                       ContextSubs, AI.getSubstitutions(),
                       Collector.getCallback());

    // Record the name of the inlined function (for cycle detection).
    InlinedFunctionNames.push_back(Callee->getName());

    auto Success = Inliner.inlineFunction(AI, Args);
    (void) Success;
    // We've already determined we should be able to inline this, so
    // we expect it to have happened.
    assert(Success && "Expected inliner to inline this function!");
    llvm::SmallVector<FullApplySite, 4> AppliesFromInlinee;
    for (auto &P : Collector.getInstructionPairs())
      AppliesFromInlinee.push_back(FullApplySite(P.first));

    recursivelyDeleteTriviallyDeadInstructions(AI.getInstruction(), true);

    NewApplies.insert(NewApplies.end(), AppliesFromInlinee.begin(),
                      AppliesFromInlinee.end());
    DA->invalidate(Caller, SILAnalysis::InvalidationKind::Everything);
    NumFunctionsInlined++;
  }

  // Record the names of the functions that we inlined.
  // We'll use this list to detect cycles in future iterations of
  // the inliner.
  for (auto CalleeName : InlinedFunctionNames) {
    InlinedFunctions.insert(std::make_pair(CallerName, CalleeName));
  }

  DEBUG(llvm::dbgs() << "\n");
  return true;
}
Exemplo n.º 16
0
/// Return true if inlining this call site is profitable.
bool SILPerformanceInliner::isProfitableToInline(FullApplySite AI,
                                              unsigned loopDepthOfAI,
                                              DominanceAnalysis *DA,
                                              SILLoopAnalysis *LA,
                                              ConstantTracker &callerTracker,
                                              unsigned &NumCallerBlocks) {
  SILFunction *Callee = AI.getReferencedFunction();

  if (Callee->getInlineStrategy() == AlwaysInline)
    return true;
  
  ConstantTracker constTracker(Callee, &callerTracker, AI);
  
  DominanceInfo *DT = DA->get(Callee);
  SILLoopInfo *LI = LA->get(Callee);

  DominanceOrder domOrder(&Callee->front(), DT, Callee->size());
  
  // Calculate the inlining cost of the callee.
  unsigned CalleeCost = 0;
  unsigned Benefit = InlineCostThreshold > 0 ? InlineCostThreshold :
                                               RemovedCallBenefit;
  Benefit += loopDepthOfAI * LoopBenefitFactor;
  int testThreshold = TestThreshold;

  while (SILBasicBlock *block = domOrder.getNext()) {
    constTracker.beginBlock();
    for (SILInstruction &I : *block) {
      constTracker.trackInst(&I);
      
      if (testThreshold >= 0) {
        // We are in test-mode: use a simplified cost model.
        CalleeCost += testCost(&I);
      } else {
        // Use the regular cost model.
        CalleeCost += unsigned(instructionInlineCost(I));
      }
      
      if (ApplyInst *AI = dyn_cast<ApplyInst>(&I)) {
        
        // Check if the callee is passed as an argument. If so, increase the
        // threshold, because inlining will (probably) eliminate the closure.
        SILInstruction *def = constTracker.getDefInCaller(AI->getCallee());
        if (def && (isa<FunctionRefInst>(def) || isa<PartialApplyInst>(def))) {
          unsigned loopDepth = LI->getLoopDepth(block);
          Benefit += ConstCalleeBenefit + loopDepth * LoopBenefitFactor;
          testThreshold *= 2;
        }
      }
    }
    // Don't count costs in blocks which are dead after inlining.
    SILBasicBlock *takenBlock = getTakenBlock(block->getTerminator(),
                                              constTracker);
    if (takenBlock) {
      Benefit += ConstTerminatorBenefit;
      domOrder.pushChildrenIf(block, [=] (SILBasicBlock *child) {
        return child->getSinglePredecessor() != block || child == takenBlock;
      });
    } else {
      domOrder.pushChildren(block);
    }
  }

  unsigned Threshold = Benefit; // The default.
  if (testThreshold >= 0) {
    // We are in testing mode.
    Threshold = testThreshold;
  } else if (AI.getFunction()->isThunk()) {
    // Only inline trivial functions into thunks (which will not increase the
    // code size).
    Threshold = TrivialFunctionThreshold;
  } else {
    // The default case.
    // We reduce the benefit if the caller is too large. For this we use a
    // cubic function on the number of caller blocks. This starts to prevent
    // inlining at about 800 - 1000 caller blocks.
    unsigned blockMinus =
      (NumCallerBlocks * NumCallerBlocks) / BlockLimitDenominator *
                          NumCallerBlocks / BlockLimitDenominator;
    if (Threshold > blockMinus + TrivialFunctionThreshold)
      Threshold -= blockMinus;
    else
      Threshold = TrivialFunctionThreshold;
  }

  if (CalleeCost > Threshold) {
    return false;
  }
  NumCallerBlocks += Callee->size();

  DEBUG(
    dumpCaller(AI.getFunction());
    llvm::dbgs() << "    decision {" << CalleeCost << " < " << Threshold <<
        ", ld=" << loopDepthOfAI << ", bb=" << NumCallerBlocks << "} " <<
        Callee->getName() << '\n';
  );
Exemplo n.º 17
0
bool SILPerformanceInliner::isProfitableToInline(FullApplySite AI,
                                                 Weight CallerWeight,
                                                 ConstantTracker &callerTracker,
                                                 int &NumCallerBlocks,
                                                 bool IsGeneric) {
  SILFunction *Callee = AI.getReferencedFunction();
  SILLoopInfo *LI = LA->get(Callee);
  ShortestPathAnalysis *SPA = getSPA(Callee, LI);
  assert(SPA->isValid());

  ConstantTracker constTracker(Callee, &callerTracker, AI);
  DominanceInfo *DT = DA->get(Callee);
  SILBasicBlock *CalleeEntry = &Callee->front();
  DominanceOrder domOrder(CalleeEntry, DT, Callee->size());

  // Calculate the inlining cost of the callee.
  int CalleeCost = 0;
  int Benefit = 0;
  
  // Start with a base benefit.
  int BaseBenefit = RemovedCallBenefit;
  const SILOptions &Opts = Callee->getModule().getOptions();
  
  // For some reason -Ounchecked can accept a higher base benefit without
  // increasing the code size too much.
  if (Opts.Optimization == SILOptions::SILOptMode::OptimizeUnchecked)
    BaseBenefit *= 2;

  CallerWeight.updateBenefit(Benefit, BaseBenefit);

  // Go through all blocks of the function, accumulate the cost and find
  // benefits.
  while (SILBasicBlock *block = domOrder.getNext()) {
    constTracker.beginBlock();
    Weight BlockW = SPA->getWeight(block, CallerWeight);

    for (SILInstruction &I : *block) {
      constTracker.trackInst(&I);
      
      CalleeCost += (int)instructionInlineCost(I);

      if (FullApplySite AI = FullApplySite::isa(&I)) {
        
        // Check if the callee is passed as an argument. If so, increase the
        // threshold, because inlining will (probably) eliminate the closure.
        SILInstruction *def = constTracker.getDefInCaller(AI.getCallee());
        if (def && (isa<FunctionRefInst>(def) || isa<PartialApplyInst>(def)))
          BlockW.updateBenefit(Benefit, RemovedClosureBenefit);
      } else if (auto *LI = dyn_cast<LoadInst>(&I)) {
        // Check if it's a load from a stack location in the caller. Such a load
        // might be optimized away if inlined.
        if (constTracker.isStackAddrInCaller(LI->getOperand()))
          BlockW.updateBenefit(Benefit, RemovedLoadBenefit);
      } else if (auto *SI = dyn_cast<StoreInst>(&I)) {
        // Check if it's a store to a stack location in the caller. Such a load
        // might be optimized away if inlined.
        if (constTracker.isStackAddrInCaller(SI->getDest()))
          BlockW.updateBenefit(Benefit, RemovedStoreBenefit);
      } else if (isa<StrongReleaseInst>(&I) || isa<ReleaseValueInst>(&I)) {
        SILValue Op = stripCasts(I.getOperand(0));
        if (SILArgument *Arg = dyn_cast<SILArgument>(Op)) {
          if (Arg->isFunctionArg() && Arg->getArgumentConvention() ==
              SILArgumentConvention::Direct_Guaranteed) {
            BlockW.updateBenefit(Benefit, RefCountBenefit);
          }
        }
      } else if (auto *BI = dyn_cast<BuiltinInst>(&I)) {
        if (BI->getBuiltinInfo().ID == BuiltinValueKind::OnFastPath)
          BlockW.updateBenefit(Benefit, FastPathBuiltinBenefit);
      }
    }
    // Don't count costs in blocks which are dead after inlining.
    SILBasicBlock *takenBlock = constTracker.getTakenBlock(block->getTerminator());
    if (takenBlock) {
      BlockW.updateBenefit(Benefit, RemovedTerminatorBenefit);
      domOrder.pushChildrenIf(block, [=] (SILBasicBlock *child) {
        return child->getSinglePredecessor() != block || child == takenBlock;
      });
    } else {
      domOrder.pushChildren(block);
    }
  }

  if (AI.getFunction()->isThunk()) {
    // Only inline trivial functions into thunks (which will not increase the
    // code size).
    if (CalleeCost > TrivialFunctionThreshold)
      return false;

    DEBUG(
      
      dumpCaller(AI.getFunction());
      llvm::dbgs() << "    decision {" << CalleeCost << " into thunk} " <<
          Callee->getName() << '\n';
    );
    return true;
  }
Exemplo n.º 18
0
// Returns the callee of an apply_inst if it is basically inlineable.
SILFunction *SILPerformanceInliner::getEligibleFunction(FullApplySite AI) {

  SILFunction *Callee = AI.getReferencedFunction();

  if (!Callee) {
    return nullptr;
  }

  // Don't inline functions that are marked with the @_semantics or @effects
  // attribute if the inliner is asked not to inline them.
  if (Callee->hasSemanticsAttrs() || Callee->hasEffectsKind()) {
    if (WhatToInline == InlineSelection::NoSemanticsAndGlobalInit) {
      return nullptr;
    }
    // The "availability" semantics attribute is treated like global-init.
    if (Callee->hasSemanticsAttrs() &&
        WhatToInline != InlineSelection::Everything &&
        Callee->hasSemanticsAttrThatStartsWith("availability")) {
      return nullptr;
    }
  } else if (Callee->isGlobalInit()) {
    if (WhatToInline != InlineSelection::Everything) {
      return nullptr;
    }
  }

  // We can't inline external declarations.
  if (Callee->empty() || Callee->isExternalDeclaration()) {
    return nullptr;
  }

  // Explicitly disabled inlining.
  if (Callee->getInlineStrategy() == NoInline) {
    return nullptr;
  }
  
  if (!Callee->shouldOptimize()) {
    return nullptr;
  }

  // We don't support this yet.
  if (AI.hasSubstitutions())
    return nullptr;

  SILFunction *Caller = AI.getFunction();

  // We don't support inlining a function that binds dynamic self because we
  // have no mechanism to preserve the original function's local self metadata.
  if (mayBindDynamicSelf(Callee)) {
    // Check if passed Self is the same as the Self of the caller.
    // In this case, it is safe to inline because both functions
    // use the same Self.
    if (AI.hasSelfArgument() && Caller->hasSelfParam()) {
      auto CalleeSelf = stripCasts(AI.getSelfArgument());
      auto CallerSelf = Caller->getSelfArgument();
      if (CalleeSelf != SILValue(CallerSelf))
        return nullptr;
    } else
      return nullptr;
  }

  // Detect self-recursive calls.
  if (Caller == Callee) {
    return nullptr;
  }

  // A non-fragile function may not be inlined into a fragile function.
  if (Caller->isFragile() &&
      !Callee->hasValidLinkageForFragileInline()) {
    if (!Callee->hasValidLinkageForFragileRef()) {
      llvm::errs() << "caller: " << Caller->getName() << "\n";
      llvm::errs() << "callee: " << Callee->getName() << "\n";
      llvm_unreachable("Should never be inlining a resilient function into "
                       "a fragile function");
    }
    return nullptr;
  }

  // Inlining self-recursive functions into other functions can result
  // in excessive code duplication since we run the inliner multiple
  // times in our pipeline
  if (calleeIsSelfRecursive(Callee)) {
    return nullptr;
  }

  return Callee;
}
Exemplo n.º 19
0
CanSILFunctionType
FunctionSignatureTransformDescriptor::createOptimizedSILFunctionType() {
  SILFunction *F = OriginalFunction;
  CanSILFunctionType FTy = F->getLoweredFunctionType();
  auto ExpectedFTy = F->getLoweredType().castTo<SILFunctionType>();
  auto HasGenericSignature = FTy->getGenericSignature() != nullptr;

  // The only way that we modify the arity of function parameters is here for
  // dead arguments. Doing anything else is unsafe since by definition non-dead
  // arguments will have SSA uses in the function. We would need to be smarter
  // in our moving to handle such cases.
  llvm::SmallVector<SILParameterInfo, 8> InterfaceParams;
  for (auto &ArgDesc : ArgumentDescList) {
    computeOptimizedArgInterface(ArgDesc, InterfaceParams);
  }

  // ResultDescs only covers the direct results; we currently can't ever
  // change an indirect result.  Piece the modified direct result information
  // back into the all-results list.
  llvm::SmallVector<SILResultInfo, 8> InterfaceResults;
  for (SILResultInfo InterfaceResult : FTy->getResults()) {
    if (InterfaceResult.isFormalDirect()) {
      auto &RV = ResultDescList[0];
      if (!RV.CalleeRetain.empty()) {
        ++NumOwnedConvertedToNotOwnedResult;
        InterfaceResults.push_back(SILResultInfo(InterfaceResult.getType(),
                                                 ResultConvention::Unowned));
        continue;
      }
    }

    InterfaceResults.push_back(InterfaceResult);
  }

  llvm::SmallVector<SILYieldInfo, 8> InterfaceYields;
  for (SILYieldInfo InterfaceYield : FTy->getYields()) {
    // For now, don't touch the yield types.
    InterfaceYields.push_back(InterfaceYield);
  }

  bool UsesGenerics = false;
  if (HasGenericSignature) {
    // Not all of the generic type parameters are used by the function
    // parameters.
    // Check which of the generic type parameters are not used and check if they
    // are used anywhere in the function body. If this is not the case, we can
    // remove the unused generic type parameters from the generic signature.
    // This makes the code both smaller and faster, because no implicit
    // parameters for type metadata and conformances need to be passed to the
    // callee at the LLVM IR level.
    // TODO: Implement a more precise analysis, so that we can eliminate only
    // those generic parameters which are not used.
    UsesGenerics = usesGenerics(F, InterfaceParams, InterfaceResults);

    // The set of used archetypes is complete now.
    if (!UsesGenerics) {
      // None of the generic type parameters are used.
      LLVM_DEBUG(llvm::dbgs() << "None of generic parameters are used by "
                              << F->getName() << "\n";
                 llvm::dbgs() << "Interface params:\n";
                 for (auto Param : InterfaceParams) {
                   Param.getType().dump();
                 }

                 llvm::dbgs() << "Interface results:\n";
                 for (auto Result : InterfaceResults) {
                   Result.getType().dump();
                 });
    }
Exemplo n.º 20
0
// Returns the callee of an apply_inst if it is basically inlinable.
SILFunction *swift::getEligibleFunction(FullApplySite AI,
                                        InlineSelection WhatToInline) {
  SILFunction *Callee = AI.getReferencedFunction();

  if (!Callee) {
    return nullptr;
  }

  // Not all apply sites can be inlined, even if they're direct.
  if (!SILInliner::canInline(AI))
    return nullptr;

  ModuleDecl *SwiftModule = Callee->getModule().getSwiftModule();
  bool IsInStdlib = (SwiftModule->isStdlibModule() ||
                     SwiftModule->isOnoneSupportModule());

  // Don't inline functions that are marked with the @_semantics or @_effects
  // attribute if the inliner is asked not to inline them.
  if (Callee->hasSemanticsAttrs() || Callee->hasEffectsKind()) {
    if (WhatToInline == InlineSelection::NoSemanticsAndGlobalInit) {
      if (shouldSkipApplyDuringEarlyInlining(AI))
        return nullptr;
      if (Callee->hasSemanticsAttr("inline_late"))
        return nullptr;
    }
    // The "availability" semantics attribute is treated like global-init.
    if (Callee->hasSemanticsAttrs() &&
        WhatToInline != InlineSelection::Everything &&
        (Callee->hasSemanticsAttrThatStartsWith("availability") ||
         (Callee->hasSemanticsAttrThatStartsWith("inline_late")))) {
      return nullptr;
    }
    if (Callee->hasSemanticsAttrs() &&
        WhatToInline == InlineSelection::Everything) {
      if (Callee->hasSemanticsAttrThatStartsWith("inline_late") && IsInStdlib) {
        return nullptr;
      }
    }

  } else if (Callee->isGlobalInit()) {
    if (WhatToInline != InlineSelection::Everything) {
      return nullptr;
    }
  }

  // We can't inline external declarations.
  if (Callee->empty() || Callee->isExternalDeclaration()) {
    return nullptr;
  }

  // Explicitly disabled inlining.
  if (Callee->getInlineStrategy() == NoInline) {
    return nullptr;
  }

  if (!Callee->shouldOptimize()) {
    return nullptr;
  }

  SILFunction *Caller = AI.getFunction();

  // We don't support inlining a function that binds dynamic self because we
  // have no mechanism to preserve the original function's local self metadata.
  if (mayBindDynamicSelf(Callee)) {
    // Check if passed Self is the same as the Self of the caller.
    // In this case, it is safe to inline because both functions
    // use the same Self.
    if (AI.hasSelfArgument() && Caller->hasSelfParam()) {
      auto CalleeSelf = stripCasts(AI.getSelfArgument());
      auto CallerSelf = Caller->getSelfArgument();
      if (CalleeSelf != SILValue(CallerSelf))
        return nullptr;
    } else
      return nullptr;
  }

  // Detect self-recursive calls.
  if (Caller == Callee) {
    return nullptr;
  }

  // A non-fragile function may not be inlined into a fragile function.
  if (Caller->isSerialized() &&
      !Callee->hasValidLinkageForFragileInline()) {
    if (!Callee->hasValidLinkageForFragileRef()) {
      llvm::errs() << "caller: " << Caller->getName() << "\n";
      llvm::errs() << "callee: " << Callee->getName() << "\n";
      llvm_unreachable("Should never be inlining a resilient function into "
                       "a fragile function");
    }
    return nullptr;
  }

  // Inlining self-recursive functions into other functions can result
  // in excessive code duplication since we run the inliner multiple
  // times in our pipeline
  if (calleeIsSelfRecursive(Callee)) {
    return nullptr;
  }

  if (!EnableSILInliningOfGenerics && AI.hasSubstitutions()) {
    // Inlining of generics is not allowed unless it is an @inline(__always)
    // or transparent function.
    if (Callee->getInlineStrategy() != AlwaysInline && !Callee->isTransparent())
      return nullptr;
  }

  // We cannot inline function with layout constraints on its generic types
  // if the corresponding substitution type does not have the same constraints.
  // The reason for this restriction is that we'd need to be able to express
  // in SIL something like casting a value of generic type T into a value of
  // generic type T: _LayoutConstraint, which is impossible currently.
  if (EnableSILInliningOfGenerics && AI.hasSubstitutions()) {
    if (!isCallerAndCalleeLayoutConstraintsCompatible(AI))
      return nullptr;
  }

  // IRGen cannot handle partial_applies containing opened_existentials
  // in its substitutions list.
  if (calleeHasPartialApplyWithOpenedExistentials(AI)) {
    return nullptr;
  }

  return Callee;
}
Exemplo n.º 21
0
/// \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;
}
Exemplo n.º 22
0
SILAnalysis::InvalidationKind
processFunction(SILFunction &F, bool EnableDiagnostics,
                unsigned AssertConfiguration) {
  DEBUG(llvm::dbgs() << "*** ConstPropagation processing: " << F.getName()
        << "\n");

  // This is the list of traits that this transformation might preserve.
  bool InvalidateBranches = false;
  bool InvalidateCalls = false;
  bool InvalidateInstructions = false;

  // Should we replace calls to assert_configuration by the assert
  // configuration.
  bool InstantiateAssertConfiguration =
      (AssertConfiguration != SILOptions::DisableReplacement);

  // The list of instructions whose evaluation resulted in error or warning.
  // This is used to avoid duplicate error reporting in case we reach the same
  // instruction from different entry points in the WorkList.
  llvm::DenseSet<SILInstruction *> ErrorSet;

  // The worklist of the constants that could be folded into their users.
  llvm::SetVector<SILInstruction *> WorkList;
  initializeWorklist(F, InstantiateAssertConfiguration, WorkList);

  llvm::SetVector<SILInstruction *> FoldedUsers;
  CastOptimizer CastOpt(
      [&](SILInstruction *I, ValueBase *V) { /* ReplaceInstUsesAction */

        InvalidateInstructions = true;
        I->replaceAllUsesWith(V);
      },
      [&](SILInstruction *I) { /* EraseAction */
        auto *TI = dyn_cast<TermInst>(I);

        if (TI) {
          // Invalidate analysis information related to branches. Replacing
          // unconditional_check_branch type instructions by a trap will also
          // invalidate branches/the CFG.
          InvalidateBranches = true;
        }

        InvalidateInstructions = true;

        WorkList.remove(I);
        I->eraseFromParent();
      });

  while (!WorkList.empty()) {
    SILInstruction *I = WorkList.pop_back_val();
    assert(I->getParent() && "SILInstruction must have parent.");

    DEBUG(llvm::dbgs() << "Visiting: " << *I);

    // Replace assert_configuration instructions by their constant value. We
    // want them to be replace even if we can't fully propagate the constant.
    if (InstantiateAssertConfiguration)
      if (auto *BI = dyn_cast<BuiltinInst>(I)) {
        if (isApplyOfBuiltin(*BI, BuiltinValueKind::AssertConf)) {
          // Instantiate the constant.
          SILBuilderWithScope B(BI);
          auto AssertConfInt = B.createIntegerLiteral(
            BI->getLoc(), BI->getType(), AssertConfiguration);
          BI->replaceAllUsesWith(AssertConfInt);
          // Schedule users for constant folding.
          WorkList.insert(AssertConfInt);
          // Delete the call.
          recursivelyDeleteTriviallyDeadInstructions(BI);

          InvalidateInstructions = true;
          continue;
        }

        // Kill calls to conditionallyUnreachable if we've folded assert
        // configuration calls.
        if (isApplyOfBuiltin(*BI, BuiltinValueKind::CondUnreachable)) {
          assert(BI->use_empty() && "use of conditionallyUnreachable?!");
          recursivelyDeleteTriviallyDeadInstructions(BI, /*force*/ true);
          InvalidateInstructions = true;
          continue;
        }
      }

    if (auto *AI = dyn_cast<ApplyInst>(I)) {
      // Apply may only come from a string.concat invocation.
      if (constantFoldStringConcatenation(AI, WorkList)) {
        // Invalidate all analysis that's related to the call graph.
        InvalidateInstructions = true;
      }

      continue;
    }

    if (isa<CheckedCastBranchInst>(I) || isa<CheckedCastAddrBranchInst>(I) ||
        isa<UnconditionalCheckedCastInst>(I) ||
        isa<UnconditionalCheckedCastAddrInst>(I)) {
      // Try to perform cast optimizations. Invalidation is handled by a
      // callback inside the cast optimizer.
      ValueBase *Result = nullptr;
      switch(I->getKind()) {
      default:
        llvm_unreachable("Unexpected instruction for cast optimizations");
      case ValueKind::CheckedCastBranchInst:
        Result = CastOpt.simplifyCheckedCastBranchInst(cast<CheckedCastBranchInst>(I));
        break;
      case ValueKind::CheckedCastAddrBranchInst:
        Result = CastOpt.simplifyCheckedCastAddrBranchInst(cast<CheckedCastAddrBranchInst>(I));
        break;
      case ValueKind::UnconditionalCheckedCastInst:
        Result = CastOpt.optimizeUnconditionalCheckedCastInst(cast<UnconditionalCheckedCastInst>(I));
        break;
      case ValueKind::UnconditionalCheckedCastAddrInst:
        Result = CastOpt.optimizeUnconditionalCheckedCastAddrInst(cast<UnconditionalCheckedCastAddrInst>(I));
        break;
      }

      if (Result) {
        if (isa<CheckedCastBranchInst>(Result) ||
            isa<CheckedCastAddrBranchInst>(Result) ||
            isa<UnconditionalCheckedCastInst>(Result) ||
            isa<UnconditionalCheckedCastAddrInst>(Result))
          WorkList.insert(cast<SILInstruction>(Result));
      }
      continue;
    }


    // Go through all users of the constant and try to fold them.
    FoldedUsers.clear();
    for (auto Use : I->getUses()) {
      SILInstruction *User = Use->getUser();
      DEBUG(llvm::dbgs() << "    User: " << *User);

      // It is possible that we had processed this user already. Do not try
      // to fold it again if we had previously produced an error while folding
      // it.  It is not always possible to fold an instruction in case of error.
      if (ErrorSet.count(User))
        continue;

      // Some constant users may indirectly cause folding of their users.
      if (isa<StructInst>(User) || isa<TupleInst>(User)) {
        WorkList.insert(User);
        continue;
      }

      // Always consider cond_fail instructions as potential for DCE.  If the
      // expression feeding them is false, they are dead.  We can't handle this
      // as part of the constant folding logic, because there is no value
      // they can produce (other than empty tuple, which is wasteful).
      if (isa<CondFailInst>(User))
        FoldedUsers.insert(User);

      // Initialize ResultsInError as a None optional.
      //
      // We are essentially using this optional to represent 3 states: true,
      // false, and n/a.
      Optional<bool> ResultsInError;

      // If we are asked to emit diagnostics, override ResultsInError with a
      // Some optional initialized to false.
      if (EnableDiagnostics)
        ResultsInError = false;

      // Try to fold the user. If ResultsInError is None, we do not emit any
      // diagnostics. If ResultsInError is some, we use it as our return value.
      SILValue C = constantFoldInstruction(*User, ResultsInError);

      // If we did not pass in a None and the optional is set to true, add the
      // user to our error set.
      if (ResultsInError.hasValue() && ResultsInError.getValue())
        ErrorSet.insert(User);

      // We failed to constant propagate... continue...
      if (!C)
        continue;

      // Ok, we have succeeded. Add user to the FoldedUsers list and perform the
      // necessary cleanups, RAUWs, etc.
      FoldedUsers.insert(User);
      ++NumInstFolded;

      InvalidateInstructions = true;

      // If the constant produced a tuple, be smarter than RAUW: explicitly nuke
      // any tuple_extract instructions using the apply.  This is a common case
      // for functions returning multiple values.
      if (auto *TI = dyn_cast<TupleInst>(C)) {
        for (auto UI = User->use_begin(), E = User->use_end(); UI != E;) {
          Operand *O = *UI++;

          // If the user is a tuple_extract, just substitute the right value in.
          if (auto *TEI = dyn_cast<TupleExtractInst>(O->getUser())) {
            SILValue NewVal = TI->getOperand(TEI->getFieldNo());
            TEI->replaceAllUsesWith(NewVal);
            TEI->dropAllReferences();
            FoldedUsers.insert(TEI);
            if (auto *Inst = dyn_cast<SILInstruction>(NewVal))
              WorkList.insert(Inst);
          }
        }

        if (User->use_empty())
          FoldedUsers.insert(TI);
      }


      // We were able to fold, so all users should use the new folded value.
      User->replaceAllUsesWith(C);

      // The new constant could be further folded now, add it to the worklist.
      if (auto *Inst = dyn_cast<SILInstruction>(C))
        WorkList.insert(Inst);
    }

    // Eagerly DCE. We do this after visiting all users to ensure we don't
    // invalidate the uses iterator.
    auto UserArray = ArrayRef<SILInstruction *>(&*FoldedUsers.begin(),
                                                FoldedUsers.size());
    if (!UserArray.empty()) {
      InvalidateInstructions = true;
    }

    recursivelyDeleteTriviallyDeadInstructions(UserArray, false,
                                               [&](SILInstruction *DeadI) {
                                                 WorkList.remove(DeadI);
                                               });
  }

  // TODO: refactor this code outside of the method. Passes should not merge
  // invalidation kinds themselves.
  using InvalidationKind = SILAnalysis::InvalidationKind;

  unsigned Inv = InvalidationKind::Nothing;
  if (InvalidateInstructions) Inv |= (unsigned) InvalidationKind::Instructions;
  if (InvalidateCalls)        Inv |= (unsigned) InvalidationKind::Calls;
  if (InvalidateBranches)     Inv |= (unsigned) InvalidationKind::Branches;
  return InvalidationKind(Inv);
}
Exemplo n.º 23
0
/// 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;
}
Exemplo n.º 24
0
/// \brief Inlines the callee of a given ApplyInst (which must be the value of a
/// FunctionRefInst referencing a function with a known body), into the caller
/// containing the ApplyInst, which must be the same function as provided to the
/// constructor of SILInliner. It only performs one step of inlining: it does
/// not recursively inline functions called by the callee.
///
/// It is the responsibility of the caller of this function to delete
/// the given ApplyInst when inlining is successful.
///
/// \returns true on success or false if it is unable to inline the function
/// (for any reason).
bool SILInliner::inlineFunction(FullApplySite AI, ArrayRef<SILValue> Args) {
  SILFunction *CalleeFunction = &Original;
  this->CalleeFunction = CalleeFunction;

  // Do not attempt to inline an apply into its parent function.
  if (AI.getFunction() == CalleeFunction)
    return false;

  SILFunction &F = getBuilder().getFunction();
  if (CalleeFunction->getName() == "_TTSg5Vs4Int8___TFVs12_ArrayBufferg9_isNativeSb"
      && F.getName() == "_TTSg5Vs4Int8___TFVs12_ArrayBufferg8endIndexSi")
    llvm::errs();

  assert(AI.getFunction() && AI.getFunction() == &F &&
         "Inliner called on apply instruction in wrong function?");
  assert(((CalleeFunction->getRepresentation()
             != SILFunctionTypeRepresentation::ObjCMethod &&
           CalleeFunction->getRepresentation()
             != SILFunctionTypeRepresentation::CFunctionPointer) ||
          IKind == InlineKind::PerformanceInline) &&
         "Cannot inline Objective-C methods or C functions in mandatory "
         "inlining");

  CalleeEntryBB = &*CalleeFunction->begin();

  // Compute the SILLocation which should be used by all the inlined
  // instructions.
  if (IKind == InlineKind::PerformanceInline) {
    Loc = InlinedLocation::getInlinedLocation(AI.getLoc());
  } else {
    assert(IKind == InlineKind::MandatoryInline && "Unknown InlineKind.");
    Loc = MandatoryInlinedLocation::getMandatoryInlinedLocation(AI.getLoc());
  }

  auto AIScope = AI.getDebugScope();
  // FIXME: Turn this into an assertion instead.
  if (!AIScope)
    AIScope = AI.getFunction()->getDebugScope();

  if (IKind == InlineKind::MandatoryInline) {
    // Mandatory inlining: every instruction inherits scope/location
    // from the call site.
    CallSiteScope = AIScope;
  } else {
    // Performance inlining. Construct a proper inline scope pointing
    // back to the call site.
    CallSiteScope = new (F.getModule())
      SILDebugScope(AI.getLoc(), &F, AIScope);
    assert(CallSiteScope->getParentFunction() == &F);
  }
  assert(CallSiteScope && "call site has no scope");

  // Increment the ref count for the inlined function, so it doesn't
  // get deleted before we can emit abstract debug info for it.
  CalleeFunction->setInlined();

  // If the caller's BB is not the last BB in the calling function, then keep
  // track of the next BB so we always insert new BBs before it; otherwise,
  // we just leave the new BBs at the end as they are by default.
  auto IBI = std::next(SILFunction::iterator(AI.getParent()));
  InsertBeforeBB = IBI != F.end() ? &*IBI : nullptr;

  // Clear argument map and map ApplyInst arguments to the arguments of the
  // callee's entry block.
  ValueMap.clear();
  assert(CalleeEntryBB->bbarg_size() == Args.size() &&
         "Unexpected number of arguments to entry block of function?");
  auto BAI = CalleeEntryBB->bbarg_begin();
  for (auto AI = Args.begin(), AE = Args.end(); AI != AE; ++AI, ++BAI)
    ValueMap.insert(std::make_pair(*BAI, *AI));

  InstructionMap.clear();
  BBMap.clear();
  // Do not allow the entry block to be cloned again
  SILBasicBlock::iterator InsertPoint =
    SILBasicBlock::iterator(AI.getInstruction());
  BBMap.insert(std::make_pair(CalleeEntryBB, AI.getParent()));
  getBuilder().setInsertionPoint(InsertPoint);
  // Recursively visit callee's BB in depth-first preorder, starting with the
  // entry block, cloning all instructions other than terminators.
  visitSILBasicBlock(CalleeEntryBB);

  // If we're inlining into a normal apply and the callee's entry
  // block ends in a return, then we can avoid a split.
  if (auto nonTryAI = dyn_cast<ApplyInst>(AI)) {
    if (ReturnInst *RI = dyn_cast<ReturnInst>(CalleeEntryBB->getTerminator())) {
      // Replace all uses of the apply instruction with the operands of the
      // return instruction, appropriately mapped.
      nonTryAI->replaceAllUsesWith(remapValue(RI->getOperand()));
      return true;
    }
  }

  // If we're inlining into a try_apply, we already have a return-to BB.
  SILBasicBlock *ReturnToBB;
  if (auto tryAI = dyn_cast<TryApplyInst>(AI)) {
    ReturnToBB = tryAI->getNormalBB();

  // Otherwise, split the caller's basic block to create a return-to BB.
  } else {
    SILBasicBlock *CallerBB = AI.getParent();
    // Split the BB and do NOT create a branch between the old and new
    // BBs; we will create the appropriate terminator manually later.
    ReturnToBB = CallerBB->splitBasicBlock(InsertPoint);
    // Place the return-to BB after all the other mapped BBs.
    if (InsertBeforeBB)
      F.getBlocks().splice(SILFunction::iterator(InsertBeforeBB), F.getBlocks(),
                           SILFunction::iterator(ReturnToBB));
    else
      F.getBlocks().splice(F.getBlocks().end(), F.getBlocks(),
                           SILFunction::iterator(ReturnToBB));

    // Create an argument on the return-to BB representing the returned value.
    auto *RetArg = new (F.getModule()) SILArgument(ReturnToBB,
                                            AI.getInstruction()->getType());
    // Replace all uses of the ApplyInst with the new argument.
    AI.getInstruction()->replaceAllUsesWith(RetArg);
  }

  // Now iterate over the callee BBs and fix up the terminators.
  for (auto BI = BBMap.begin(), BE = BBMap.end(); BI != BE; ++BI) {
    getBuilder().setInsertionPoint(BI->second);

    // Modify return terminators to branch to the return-to BB, rather than
    // trying to clone the ReturnInst.
    if (ReturnInst *RI = dyn_cast<ReturnInst>(BI->first->getTerminator())) {
      auto thrownValue = remapValue(RI->getOperand());
      getBuilder().createBranch(Loc.getValue(), ReturnToBB,
                                thrownValue);
      continue;
    }

    // Modify throw terminators to branch to the error-return BB, rather than
    // trying to clone the ThrowInst.
    if (ThrowInst *TI = dyn_cast<ThrowInst>(BI->first->getTerminator())) {
      if (auto *A = dyn_cast<ApplyInst>(AI)) {
        (void)A;
        assert(A->isNonThrowing() &&
               "apply of a function with error result must be non-throwing");
        getBuilder().createUnreachable(Loc.getValue());
        continue;
      }
      auto tryAI = cast<TryApplyInst>(AI);
      auto returnedValue = remapValue(TI->getOperand());
      getBuilder().createBranch(Loc.getValue(), tryAI->getErrorBB(),
                                returnedValue);
      continue;
    }

    // Otherwise use normal visitor, which clones the existing instruction
    // but remaps basic blocks and values.
    visit(BI->first->getTerminator());
  }

  return true;
}