llvm/lib/CodeGen/MachineDomTreeUpdater.cpp

   1 //===- MachineDomTreeUpdater.cpp -----------------------------------------===//
   2 //
   3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
   4 // See https://llvm.org/LICENSE.txt for license information.
   5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
   6 //
   7 //===----------------------------------------------------------------------===//
   8 //
   9 // This file implements the MachineDomTreeUpdater class, which provides a
  10 // uniform way to update dominator tree related data structures.
  11 //
  12 //===----------------------------------------------------------------------===//
  13
  14 #include "llvm/CodeGen/MachineDomTreeUpdater.h"
  15 #include "llvm/ADT/SmallSet.h"
  16 #include "llvm/Analysis/GenericDomTreeUpdaterImpl.h"
  17 #include "llvm/CodeGen/MachinePostDominators.h"
  18 #include "llvm/Support/GenericDomTree.h"
  19 #include <algorithm>
  20 #include <functional>
  21 #include <utility>
  22
  23 namespace llvm {
  24
  25 template class GenericDomTreeUpdater<
  26     MachineDomTreeUpdater, MachineDominatorTree, MachinePostDominatorTree>;
  27
  28 template void
  29 GenericDomTreeUpdater<MachineDomTreeUpdater, MachineDominatorTree,
  30                       MachinePostDominatorTree>::recalculate(MachineFunction
  31                                                                  &MF);
  32
  33 bool MachineDomTreeUpdater::forceFlushDeletedBB() {
  34   if (DeletedBBs.empty())
  35     return false;
  36
  37   for (auto *BB : DeletedBBs) {
  38     eraseDelBBNode(BB);
  39     BB->eraseFromParent();
  40   }
  41   DeletedBBs.clear();
  42   return true;
  43 }
  44
  45 // The DT and PDT require the nodes related to updates
  46 // are not deleted when update functions are called.
  47 // So MachineBasicBlock deletions must be pended when the
  48 // UpdateStrategy is Lazy. When the UpdateStrategy is
  49 // Eager, the MachineBasicBlock will be deleted immediately.
  50 void MachineDomTreeUpdater::deleteBB(MachineBasicBlock *DelBB) {
  51   validateDeleteBB(DelBB);
  52   if (Strategy == UpdateStrategy::Lazy) {
  53     DeletedBBs.insert(DelBB);
  54     return;
  55   }
  56
  57   eraseDelBBNode(DelBB);
  58   DelBB->eraseFromParent();
  59 }
  60
  61 void MachineDomTreeUpdater::validateDeleteBB(MachineBasicBlock *DelBB) {
  62   assert(DelBB && "Invalid push_back of nullptr DelBB.");
  63   assert(DelBB->pred_empty() && "DelBB has one or more predecessors.");
  64 }
  65
  66 } // namespace llvm