| //===--- SimplifyUnreachableContainingBlocks.cpp --------------------------===// |
| // |
| // This source file is part of the Swift.org open source project |
| // |
| // Copyright (c) 2014 - 2017 Apple Inc. and the Swift project authors |
| // Licensed under Apache License v2.0 with Runtime Library Exception |
| // |
| // See https://swift.org/LICENSE.txt for license information |
| // See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors |
| // |
| //===----------------------------------------------------------------------===// |
| /// |
| /// \file |
| /// |
| /// This file contains a simple utility pass that simplifies blocks that contain |
| /// unreachables by eliminating all other instructions. This includes |
| /// instructions with side-effects and no-return functions. It is only intended |
| /// to be used to simplify IR for testing or exploratory purposes. |
| /// |
| //===----------------------------------------------------------------------===// |
| |
| #include "swift/SILOptimizer/PassManager/Passes.h" |
| #include "swift/SIL/SILBasicBlock.h" |
| #include "swift/SILOptimizer/PassManager/Transforms.h" |
| |
| using namespace swift; |
| |
| namespace { |
| |
| class SimplifyUnreachableContainingBlocks : public SILFunctionTransform { |
| void run() override { |
| // For each block... |
| for (auto &BB : *getFunction()) { |
| // If the block does not contain an unreachable, just continue. There is |
| // no further work to do. |
| auto *UI = dyn_cast<UnreachableInst>(BB.getTerminator()); |
| if (!UI) |
| continue; |
| |
| // Otherwise, eliminate all other instructions in the block. |
| for (auto II = BB.begin(); &*II != UI;) { |
| // Avoid iterator invalidation. |
| auto *I = &*II; |
| ++II; |
| |
| I->replaceAllUsesOfAllResultsWithUndef(); |
| I->eraseFromParent(); |
| } |
| } |
| } |
| }; |
| |
| } // end anonymous namespace |
| |
| //===----------------------------------------------------------------------===// |
| // Top Level Entry Point |
| //===----------------------------------------------------------------------===// |
| |
| SILTransform *swift::createSimplifyUnreachableContainingBlocks() { |
| return new SimplifyUnreachableContainingBlocks(); |
| } |