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60 lines
1.8 KiB
C++
60 lines
1.8 KiB
C++
//===--- TransitivelyUnreachableBlocks.h ------------------------*- C++ -*-===//
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//
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// This source file is part of the Swift.org open source project
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//
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// Copyright (c) 2014 - 2017 Apple Inc. and the Swift project authors
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// Licensed under Apache License v2.0 with Runtime Library Exception
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//
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// See https://swift.org/LICENSE.txt for license information
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// See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
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//
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//===----------------------------------------------------------------------===//
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#ifndef SWIFT_SIL_TRANSITIVELYUNREACHABLEBLOCKS_H
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#define SWIFT_SIL_TRANSITIVELYUNREACHABLEBLOCKS_H
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#include "swift/SIL/PostOrder.h"
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#include "swift/SIL/SILBasicBlock.h"
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#include "llvm/ADT/SmallPtrSet.h"
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namespace swift {
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/// This is a simple unreachable dataflow analysis that determines all blocks
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/// that are post-dominated by no-return functions, no-return builtins and
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/// unreachables. It is needed to determine if the a value definition can have a
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/// lack of users ignored along a specific path.
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class TransitivelyUnreachableBlocksInfo {
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llvm::SmallPtrSet<const SILBasicBlock *, 32> UnreachableBlocks;
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public:
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TransitivelyUnreachableBlocksInfo(const PostOrderFunctionInfo &POFI) {
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for (SILBasicBlock *Block : POFI.getPostOrder()) {
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if (isa<UnreachableInst>(Block->getTerminator())) {
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UnreachableBlocks.insert(Block);
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continue;
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}
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if (Block->succ_empty()) {
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continue;
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}
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if (any_of(Block->getSuccessorBlocks(),
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[this](SILBasicBlock *SuccBlock) -> bool {
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return !UnreachableBlocks.count(SuccBlock);
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})) {
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continue;
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}
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UnreachableBlocks.insert(Block);
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}
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}
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bool isUnreachable(const SILBasicBlock *BB) const {
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return UnreachableBlocks.count(BB);
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}
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};
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} // namespace swift
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#endif
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