| //===- BarrierNoopPass.cpp - A barrier pass for the pass manager ----------===// |
| // |
| // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. |
| // See https://llvm.org/LICENSE.txt for license information. |
| // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception |
| // |
| //===----------------------------------------------------------------------===// |
| // |
| // NOTE: DO NOT USE THIS IF AVOIDABLE |
| // |
| // This pass is a nonce pass intended to allow manipulation of the implicitly |
| // nesting pass manager. For example, it can be used to cause a CGSCC pass |
| // manager to be closed prior to running a new collection of function passes. |
| // |
| // FIXME: This is a huge HACK. This should be removed when the pass manager's |
| // nesting is made explicit instead of implicit. |
| // |
| //===----------------------------------------------------------------------===// |
| |
| #include "llvm/Pass.h" |
| #include "llvm/Transforms/IPO.h" |
| using namespace llvm; |
| |
| namespace { |
| /// A nonce module pass used to place a barrier in a pass manager. |
| /// |
| /// There is no mechanism for ending a CGSCC pass manager once one is started. |
| /// This prevents extension points from having clear deterministic ordering |
| /// when they are phrased as non-module passes. |
| class BarrierNoop : public ModulePass { |
| public: |
| static char ID; // Pass identification. |
| |
| BarrierNoop() : ModulePass(ID) { |
| initializeBarrierNoopPass(*PassRegistry::getPassRegistry()); |
| } |
| |
| bool runOnModule(Module &M) override { return false; } |
| }; |
| } |
| |
| ModulePass *llvm::createBarrierNoopPass() { return new BarrierNoop(); } |
| |
| char BarrierNoop::ID = 0; |
| INITIALIZE_PASS(BarrierNoop, "barrier", "A No-Op Barrier Pass", |
| false, false) |