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/Analysis/GenericDomTreeUpdaterImpl.h"
  16 #include "llvm/CodeGen/MachinePostDominators.h"
  17
  18 namespace llvm {
  19
  20 template class GenericDomTreeUpdater<
  21     MachineDomTreeUpdater, MachineDominatorTree, MachinePostDominatorTree>;
  22
  23 template void
  24 GenericDomTreeUpdater<MachineDomTreeUpdater, MachineDominatorTree,
  25                       MachinePostDominatorTree>::recalculate(MachineFunction
  26                                                                  &MF);
  27
  28 template void GenericDomTreeUpdater<
  29     MachineDomTreeUpdater, MachineDominatorTree,
  30     MachinePostDominatorTree>::applyUpdatesImpl</*IsForward=*/true>();
  31 template void GenericDomTreeUpdater<
  32     MachineDomTreeUpdater, MachineDominatorTree,
  33     MachinePostDominatorTree>::applyUpdatesImpl</*IsForward=*/false>();
  34
  35 bool MachineDomTreeUpdater::forceFlushDeletedBB() {
  36   if (DeletedBBs.empty())
  37     return false;
  38
  39   for (auto *BB : DeletedBBs) {
  40     eraseDelBBNode(BB);
  41     BB->eraseFromParent();
  42   }
  43   DeletedBBs.clear();
  44   return true;
  45 }
  46
  47 // The DT and PDT require the nodes related to updates
  48 // are not deleted when update functions are called.
  49 // So MachineBasicBlock deletions must be pended when the
  50 // UpdateStrategy is Lazy. When the UpdateStrategy is
  51 // Eager, the MachineBasicBlock will be deleted immediately.
  52 void MachineDomTreeUpdater::deleteBB(MachineBasicBlock *DelBB) {
  53   validateDeleteBB(DelBB);
  54   if (Strategy == UpdateStrategy::Lazy) {
  55     DeletedBBs.insert(DelBB);
  56     return;
  57   }
  58
  59   eraseDelBBNode(DelBB);
  60   DelBB->eraseFromParent();
  61 }
  62
  63 void MachineDomTreeUpdater::validateDeleteBB(MachineBasicBlock *DelBB) {
  64   assert(DelBB && "Invalid push_back of nullptr DelBB.");
  65   assert(DelBB->pred_empty() && "DelBB has one or more predecessors.");
  66 }
  67
  68 } // namespace llvm