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Jon Meow
90f04700e2
With this, only main.cpp instantiates an arena. Maybe we'll want to split that up more later (e.g., so that the runtime interpreter uses its own arena), but given the intent to have type-checking update the AST, I thought this was a reasonable approach for now in order to avoid ownership complexities. Fixes #769
56 lines
1.5 KiB
C++
56 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 "executable_semantics/common/ptr.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) -> Ptr<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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Ptr<T> ptr = smart_ptr->Instance();
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arena.push_back(std::move(smart_ptr));
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return 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() -> Ptr<T> { return Ptr<T>(&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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} // namespace Carbon
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#endif // EXECUTABLE_SEMANTICS_COMMON_ARENA_H_
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