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78 lines
2.5 KiB
C++
78 lines
2.5 KiB
C++
//===--- DominancePoint.h - Dominance points --------------------*- 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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//
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// This file defines types relating to local dominance calculations
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// during the emission of a function.
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//
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// During the emission of a function, the LLVM IR is not well-formed enough
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// to do accurate dominance computations. For example, a basic block may
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// appear to have a single predecessor, but that may be because a different
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// predecessor has not yet been added.
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//
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//===----------------------------------------------------------------------===//
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#ifndef SWIFT_IRGEN_DOMINANCEPOINT_H
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#define SWIFT_IRGEN_DOMINANCEPOINT_H
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#include <cassert>
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#include <cstdint>
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namespace swift {
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namespace irgen {
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class IRGenFunction;
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/// An opaque class for storing keys for the dominance callback. The
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/// key is assumed to be something like a (uniqued) pointer, and a
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/// null pointer is assumed to mean a non-dominating point.
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class DominancePoint {
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uintptr_t Value;
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enum : uintptr_t {
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Universal = 0,
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};
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explicit DominancePoint(uintptr_t value) : Value(value) {}
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public:
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explicit DominancePoint(void *value)
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: Value(reinterpret_cast<uintptr_t>(value)) {
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assert(isOrdinary());
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}
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/// Something about the definition is known to dominate all possible
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/// places that will use it.
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static DominancePoint universal() { return DominancePoint(Universal); }
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bool isOrdinary() const {
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return Value != Universal;
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}
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bool isUniversal() const {
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return Value == Universal;
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}
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template <class T> T* as() const {
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assert(isOrdinary());
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return reinterpret_cast<T*>(Value);
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}
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bool operator==(DominancePoint other) const { return Value == other.Value; }
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};
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/// A dominance resolver is a function that answers the question of
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/// whether one dominance point dominates another.
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///
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/// It will only be asked this question with ordinary dominance points.
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using DominanceResolverFunction = bool(*)(IRGenFunction &IGF,
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DominancePoint curPoint,
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DominancePoint definingPoint);
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}
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}
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#endif
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