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011358edd6
This removes the ambiguity when casting from a SingleValueInstruction to SILNode, which makes the code simpler. E.g. the "isRepresentativeSILNode" logic is not needed anymore. Also, it reduces the size of the most used instruction class - SingleValueInstruction - by one pointer. Conceptually, SILInstruction is still a SILNode. But implementation-wise SILNode is not a base class of SILInstruction anymore. Only the two sub-classes of SILInstruction - SingleValueInstruction and NonSingleValueInstruction - inherit from SILNode. SingleValueInstruction's SILNode is embedded into a ValueBase and its relative offset in the class is the same as in NonSingleValueInstruction (see SILNodeOffsetChecker). This makes it possible to cast from a SILInstruction to a SILNode without knowing which SILInstruction sub-class it is. Casting to SILNode cannot be done implicitly, but only with an LLVM `cast` or with SILInstruction::asSILNode(). But this is a rare case anyway.
55 lines
1.5 KiB
C++
55 lines
1.5 KiB
C++
//===--- SILUndef.h - SIL Undef Value Representation ------------*- 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_UNDEF_H
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#define SWIFT_SIL_UNDEF_H
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#include "swift/Basic/Compiler.h"
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#include "swift/SIL/SILValue.h"
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namespace swift {
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class SILArgument;
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class SILInstruction;
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class SILModule;
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class SILUndef : public ValueBase {
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SILUndef(SILType type);
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public:
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void operator=(const SILArgument &) = delete;
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void operator delete(void *, size_t) = delete;
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static SILUndef *get(SILType ty, SILModule &m);
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static SILUndef *get(SILType ty, const SILFunction &f);
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template <class OwnerTy>
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static SILUndef *getSentinelValue(SILType type, OwnerTy owner) {
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// Ownership kind isn't used here, the value just needs to have a unique
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// address.
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return new (*owner) SILUndef(type);
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}
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ValueOwnershipKind getOwnershipKind() const { return OwnershipKind::None; }
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static bool classof(const SILArgument *) = delete;
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static bool classof(const SILInstruction *) = delete;
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static bool classof(SILNodePointer node) {
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return node->getKind() == SILNodeKind::SILUndef;
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}
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};
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} // end swift namespace
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#endif
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