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https://github.com/carbon-language/carbon-lang.git
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Jon Ross-Perkins
b80e294b6c
WDYT of this, to avoid raw int32_t indices? I was looking at the code again and found it hard to sort out. I think this doesn't have overhead.
50 lines
1.3 KiB
C++
50 lines
1.3 KiB
C++
// Part of the Carbon Language project, under the Apache License v2.0 with LLVM
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// Exceptions. See /LICENSE for license information.
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// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
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#ifndef CARBON_TOOLCHAIN_SEMANTICS_NODE_REF_H_
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#define CARBON_TOOLCHAIN_SEMANTICS_NODE_REF_H_
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#include <cstdint>
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#include "common/ostream.h"
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#include "toolchain/semantics/node_kind.h"
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namespace Carbon::Semantics {
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// Type-safe storage of NodeStore indices.
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struct NodeStoreIndex {
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explicit NodeStoreIndex(int32_t index) : index(index) {}
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operator int32_t() const { return index; }
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int32_t index;
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};
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// The standard structure for nodes.
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//
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// This flyweight pattern is used so that each subtype can be stored in its own
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// vector, minimizing memory consumption and heap fragmentation when large
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// quantities are being created.
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class NodeRef {
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public:
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NodeRef() : NodeRef(NodeKind::Invalid, NodeStoreIndex(-1)) {}
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auto kind() -> NodeKind { return kind_; }
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private:
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template <typename... StoredNodeT>
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friend class NodeStoreBase;
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NodeRef(NodeKind kind, NodeStoreIndex index) : kind_(kind), index_(index) {}
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NodeKind kind_;
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// The index of the named entity within its list.
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NodeStoreIndex index_;
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};
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} // namespace Carbon::Semantics
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#endif // CARBON_TOOLCHAIN_SEMANTICS_NODE_REF_H_
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