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Jon Ross-Perkins
b828093c87
I couldn't figure out a way to actually hit a reasonable out-of-memory case once I add the maximum interpreter step count. However, the step count limit seems more important. I've moved the todo stack limit out of function calls because there are plenty of ways to build up the todo stack without any function calls. Fixes #2791
76 lines
2.1 KiB
C++
76 lines
2.1 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_EXPLORER_INTERPRETER_STACK_H_
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#define CARBON_EXPLORER_INTERPRETER_STACK_H_
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#include <cstddef>
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#include <iterator>
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#include <vector>
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#include "common/check.h"
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namespace Carbon {
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// A stack data structure.
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template <class T>
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struct Stack {
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// NOLINTNEXTLINE(readability-identifier-naming)
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using const_iterator = typename std::vector<T>::const_reverse_iterator;
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// Creates an empty instance.
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Stack() = default;
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// Creates an instance containing just `x`.
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explicit Stack(T x) : Stack() { Push(std::move(x)); }
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// Pushes `x` onto the top of the stack.
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void Push(T x) { elements_.push_back(std::move(x)); }
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// Removes and returns the top element of the stack.
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//
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// - Requires: !this->IsEmpty()
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auto Pop() -> T {
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CARBON_CHECK(!empty()) << "Can't pop from empty stack.";
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auto r = std::move(elements_.back());
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elements_.pop_back();
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return r;
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}
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// Removes the top `n` elements of the stack.
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//
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// - Requires: n >= 0 && n <= Count()
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void Pop(int n) {
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CARBON_CHECK(n >= 0) << "Negative pop count disallowed.";
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CARBON_CHECK(static_cast<size_t>(n) <= elements_.size())
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<< "Can only pop as many elements as stack has.";
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elements_.erase(elements_.end() - n, elements_.end());
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}
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// Returns the top element of the stack.
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//
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// - Requires: !this->IsEmpty()
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auto Top() const -> const T& {
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CARBON_CHECK(!empty()) << "Empty stack has no Top().";
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return elements_.back();
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}
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// Returns `true` iff `Count() > 0`.
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auto empty() const -> bool { return elements_.empty(); }
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// Returns the number of elements in `*this`.
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auto size() const -> int { return elements_.size(); }
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// Iterates over the Stack from top to bottom.
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auto begin() const -> const_iterator { return elements_.crbegin(); }
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auto end() const -> const_iterator { return elements_.crend(); }
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private:
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std::vector<T> elements_;
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};
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} // namespace Carbon
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#endif // CARBON_EXPLORER_INTERPRETER_STACK_H_
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