C++ ApplyInst::getFunction方法代码示例

/// Optimize placement of initializer calls given a list of calls to the
/// same initializer. All original initialization points must be dominated by
/// the final initialization calls.
///
/// The current heuristic hoists all initialization points within a function to
/// a single dominating call in the outer loop preheader.
void SILGlobalOpt::placeInitializers(SILFunction *InitF,
                                     ArrayRef<ApplyInst *> Calls) {
  LLVM_DEBUG(llvm::dbgs() << "GlobalOpt: calls to "
             << Demangle::demangleSymbolAsString(InitF->getName())
             << " : " << Calls.size() << "\n");
  // Map each initializer-containing function to its final initializer call.
  llvm::DenseMap<SILFunction *, ApplyInst *> ParentFuncs;
  for (auto *AI : Calls) {
    assert(AI->getNumArguments() == 0 && "ill-formed global init call");
    assert(cast<FunctionRefInst>(AI->getCallee())->getReferencedFunction()
           == InitF && "wrong init call");
    SILFunction *ParentF = AI->getFunction();
    DominanceInfo *DT = DA->get(ParentF);
    ApplyInst *HoistAI =
        getHoistedApplyForInitializer(AI, DT, InitF, ParentF, ParentFuncs);

    // If we were unable to find anything, just go onto the next apply.
    if (!HoistAI) {
      continue;
    }

    // Otherwise, move this call to the outermost loop preheader.
    SILBasicBlock *BB = HoistAI->getParent();
    typedef llvm::DomTreeNodeBase<SILBasicBlock> DomTreeNode;
    DomTreeNode *Node = DT->getNode(BB);
    while (Node) {
      SILBasicBlock *DomParentBB = Node->getBlock();
      if (isAvailabilityCheck(DomParentBB)) {
        LLVM_DEBUG(llvm::dbgs() << "  don't hoist above availability check "
                                   "at bb"
                                << DomParentBB->getDebugID() << "\n");
        break;
      }
      BB = DomParentBB;
      if (!isInLoop(BB))
        break;
      Node = Node->getIDom();
    }

    if (BB == HoistAI->getParent()) {
      // BB is either unreachable or not in a loop.
      LLVM_DEBUG(llvm::dbgs() << "  skipping (not in a loop): " << *HoistAI
                              << "  in " << HoistAI->getFunction()->getName()
                              << "\n");
      continue;
    }

    LLVM_DEBUG(llvm::dbgs() << "  hoisting: " << *HoistAI << "  in "
                       << HoistAI->getFunction()->getName() << "\n");
    HoistAI->moveBefore(&*BB->begin());
    placeFuncRef(HoistAI, DT);
    HasChanged = true;
  }
}

/// Try to CSE the users of \p From to the users of \p To.
/// The original users of \p To are passed in ToApplyWitnessUsers.
/// Returns true on success.
static bool tryToCSEOpenExtCall(OpenExistentialAddrInst *From,
                                OpenExistentialAddrInst *To,
                                ApplyWitnessPair ToApplyWitnessUsers,
                                DominanceInfo *DA) {
  assert(From != To && "Can't replace instruction with itself");

  ApplyInst *FromAI = nullptr;
  ApplyInst *ToAI = nullptr;
  WitnessMethodInst *FromWMI = nullptr;
  WitnessMethodInst *ToWMI = nullptr;
  std::tie(FromAI, FromWMI) = getOpenExistentialUsers(From);
  std::tie(ToAI, ToWMI) = ToApplyWitnessUsers;

  // Make sure that the OEA instruction has exactly two expected users.
  if (!FromAI || !ToAI || !FromWMI || !ToWMI)
    return false;

  // Make sure we are calling the same method.
  if (FromWMI->getMember() != ToWMI->getMember())
    return false;

  // We are going to reuse the TO-WMI, so make sure it dominates the call site.
  if (!DA->properlyDominates(ToWMI, FromWMI))
    return false;

  SILBuilder Builder(FromAI);
  // Make archetypes used by the ToAI available to the builder.
  SILOpenedArchetypesTracker OpenedArchetypesTracker(*FromAI->getFunction());
  OpenedArchetypesTracker.registerUsedOpenedArchetypes(ToAI);
  Builder.setOpenedArchetypesTracker(&OpenedArchetypesTracker);

  assert(FromAI->getArguments().size() == ToAI->getArguments().size() &&
         "Invalid number of arguments");

  // Don't handle any apply instructions that involve substitutions.
  if (ToAI->getSubstitutions().size() != 1) return false;

  // Prepare the Apply args.
  SmallVector<SILValue, 8> Args;
  for (auto Op : FromAI->getArguments()) {
      Args.push_back(Op == From ? To : Op);
  }

  auto FnTy = ToAI->getSubstCalleeSILType();
  auto ResTy = FnTy.castTo<SILFunctionType>()->getSILResult();

  ApplyInst *NAI = Builder.createApply(ToAI->getLoc(), ToWMI, FnTy, ResTy,
                                       ToAI->getSubstitutions(), Args,
                                       ToAI->isNonThrowing());
  FromAI->replaceAllUsesWith(NAI);
  FromAI->eraseFromParent();
  NumOpenExtRemoved++;
  return true;
}

/// Optimize placement of initializer calls given a list of calls to the
/// same initializer. All original initialization points must be dominated by
/// the final initialization calls.
///
/// The current heuristic hoists all initialization points within a function to
/// a single dominating call in the outer loop preheader.
void SILGlobalOpt::placeInitializers(SILFunction *InitF,
                                     ArrayRef<ApplyInst*> Calls) {
  DEBUG(llvm::dbgs() << "GlobalOpt: calls to "
        << demangle_wrappers::demangleSymbolAsString(InitF->getName())
        << " : " << Calls.size() << "\n");
  // Map each initializer-containing function to its final initializer call.
  llvm::DenseMap<SILFunction*, ApplyInst*> ParentFuncs;
  for (auto *AI : Calls) {
    assert(AI->getNumArguments() == 0 && "ill-formed global init call");
    assert(cast<FunctionRefInst>(AI->getCallee())->getReferencedFunction()
           == InitF && "wrong init call");

    SILFunction *ParentF = AI->getFunction();
    DominanceInfo *DT = DA->get(ParentF);
    auto PFI = ParentFuncs.find(ParentF);
    ApplyInst *HoistAI = nullptr;
    if (PFI != ParentFuncs.end()) {
      // Found a replacement for this init call.
      // Ensure the replacement dominates the original call site.
      ApplyInst *CommonAI = PFI->second;
      assert(cast<FunctionRefInst>(CommonAI->getCallee())
             ->getReferencedFunction() == InitF &&
             "ill-formed global init call");
      SILBasicBlock *DomBB =
        DT->findNearestCommonDominator(AI->getParent(), CommonAI->getParent());
      
      // We must not move initializers around availability-checks.
      if (!isAvailabilityCheckOnDomPath(DomBB, CommonAI->getParent(), DT)) {
        if (DomBB != CommonAI->getParent()) {
          CommonAI->moveBefore(&*DomBB->begin());
          placeFuncRef(CommonAI, DT);
          
          // Try to hoist the existing AI again if we move it to another block,
          // e.g. from a loop exit into the loop.
          HoistAI = CommonAI;
        }
        AI->replaceAllUsesWith(CommonAI);
        AI->eraseFromParent();
        HasChanged = true;
      }
    } else {
      ParentFuncs[ParentF] = AI;
      
      // It's the first time we found a call to InitF in this function, so we
      // try to hoist it out of any loop.
      HoistAI = AI;
    }
    if (HoistAI) {
      // Move this call to the outermost loop preheader.
      SILBasicBlock *BB = HoistAI->getParent();
      typedef llvm::DomTreeNodeBase<SILBasicBlock> DomTreeNode;
      DomTreeNode *Node = DT->getNode(BB);
      while (Node) {
        SILBasicBlock *DomParentBB = Node->getBlock();
        if (isAvailabilityCheck(DomParentBB)) {
          DEBUG(llvm::dbgs() << "  don't hoist above availability check at bb" <<
                DomParentBB->getDebugID() << "\n");
          break;
        }
        BB = DomParentBB;
        if (!isInLoop(BB))
          break;
        Node = Node->getIDom();
      }
      if (BB == HoistAI->getParent()) {
        // BB is either unreachable or not in a loop.
        DEBUG(llvm::dbgs() << "  skipping (not in a loop): " << *HoistAI
              << "  in " << HoistAI->getFunction()->getName() << "\n");
      }
      else {
        DEBUG(llvm::dbgs() << "  hoisting: " << *HoistAI
              << "  in " << HoistAI->getFunction()->getName() << "\n");
        HoistAI->moveBefore(&*BB->begin());
        placeFuncRef(HoistAI, DT);
        HasChanged = true;
      }
    }
  }
}