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58 lines
1.5 KiB
C++
58 lines
1.5 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 EXECUTABLE_SEMANTICS_COMMON_ARENA_H_
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#define EXECUTABLE_SEMANTICS_COMMON_ARENA_H_
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#include <memory>
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#include <vector>
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#include "llvm/Support/ManagedStatic.h"
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namespace Carbon {
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class Arena {
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public:
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// Allocates an object in the arena, returning a pointer to it.
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template <typename T, typename... Args>
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auto New(Args&&... args) -> T* {
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auto smart_ptr =
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std::make_unique<ArenaEntryTyped<T>>(std::forward<Args>(args)...);
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T* raw_ptr = smart_ptr->Instance();
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arena.push_back(std::move(smart_ptr));
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return raw_ptr;
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}
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private:
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// Virtualizes arena entries so that a single vector can contain many types,
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// avoiding templated statics.
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class ArenaEntry {
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public:
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virtual ~ArenaEntry() = default;
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};
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// Templated destruction of a pointer.
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template <typename T>
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class ArenaEntryTyped : public ArenaEntry {
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public:
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template <typename... Args>
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explicit ArenaEntryTyped(Args&&... args)
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: instance(std::forward<Args>(args)...) {}
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auto Instance() -> T* { return &instance; }
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private:
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T instance;
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};
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// Manages allocations in an arena for destruction at shutdown.
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std::vector<std::unique_ptr<ArenaEntry>> arena;
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};
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extern llvm::ManagedStatic<Arena> global_arena;
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} // namespace Carbon
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#endif // EXECUTABLE_SEMANTICS_COMMON_ARENA_H_
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