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Richard SmithandJon Ross-Perkins
e060342411
Instead of building the definition of a thunk immediately when we generate the thunk declaration, wait until we reach the `}` of the outermost class, interface, etc. -- at the same time when we would parse the definition of the thunk if it were defined inline. This fixes issues where we fail to define the thunk because it requires an enclosing class to be complete, or its definition depends on something declared later in the enclosing class. Make the representation of a suspended function scope, and its constituent suspended components, be move-only, and switch to passing it around by rvalue reference instead of by value because it's expensive both to move and especially to copy. --------- Co-authored-by: Jon Ross-Perkins <jperkins@google.com>
106 lines
3.4 KiB
C++
106 lines
3.4 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_COMMON_ARRAY_STACK_H_
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#define CARBON_COMMON_ARRAY_STACK_H_
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#include "common/check.h"
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#include "llvm/ADT/ArrayRef.h"
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#include "llvm/ADT/SmallVector.h"
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namespace Carbon {
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// Provides a stack of arrays. Only the array at the top of the stack can have
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// elements added.
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//
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// Example usage:
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// // Push to start.
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// PushArray();
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// // Add values.
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// AppendToTop(3);
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// // Look at values.
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// PeekArray();
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// // Pop when done.
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// PopArray();
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//
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// By using a single vector for elements, the intent is that as arrays are
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// pushed and popped, the same storage will be reused. This should yield
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// efficiencies for heap allocations. For example, in the toolchain we
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// frequently have an array per scope, and only add to the current scope's
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// array; this allows better reuse when entering and leaving scopes.
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template <typename ValueT>
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class ArrayStack {
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public:
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// Pushes a new array onto the stack.
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auto PushArray() -> void { array_offsets_.push_back(values_.size()); }
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// Pops the top array from the stack.
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auto PopArray() -> void {
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auto region = array_offsets_.pop_back_val();
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values_.truncate(region);
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}
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// Returns the top array from the stack.
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auto PeekArray() const -> llvm::ArrayRef<ValueT> {
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CARBON_CHECK(!array_offsets_.empty());
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return llvm::ArrayRef(values_).slice(array_offsets_.back());
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}
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auto PeekArray() -> llvm::MutableArrayRef<ValueT> {
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CARBON_CHECK(!array_offsets_.empty());
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return llvm::MutableArrayRef(values_).slice(array_offsets_.back());
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}
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// Returns the array at a specific index.
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auto PeekArrayAt(int index) const -> llvm::ArrayRef<ValueT> {
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auto ref = llvm::ArrayRef(values_).slice(array_offsets_[index]);
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if (index + 1 < static_cast<int>(array_offsets_.size())) {
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ref = ref.take_front(array_offsets_[index + 1] - array_offsets_[index]);
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}
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return ref;
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}
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// Returns the full set of values on the stack, regardless of whether any
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// arrays are pushed.
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auto PeekAllValues() const -> llvm::ArrayRef<ValueT> { return values_; }
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// Appends a value to the top array on the stack.
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auto AppendToTop(const ValueT& value) -> void {
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CARBON_CHECK(!array_offsets_.empty(),
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"Must call PushArray before AppendToTop.");
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values_.push_back(value);
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}
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// Appends a value to the top array on the stack.
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auto AppendToTop(ValueT&& value) -> void {
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CARBON_CHECK(!array_offsets_.empty(),
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"Must call PushArray before AppendToTop.");
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values_.push_back(std::move(value));
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}
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// Adds multiple values to the top array on the stack.
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auto AppendToTop(llvm::ArrayRef<ValueT> values) -> void {
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CARBON_CHECK(!array_offsets_.empty(),
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"Must call PushArray before PushValues.");
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llvm::append_range(values_, values);
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}
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// Returns the current number of values in all arrays.
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auto all_values_size() const -> size_t { return values_.size(); }
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// Returns true if the stack has no arrays pushed.
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auto empty() const -> bool { return array_offsets_.empty(); }
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private:
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// For each pushed array, the start index in `values_`.
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llvm::SmallVector<int32_t> array_offsets_;
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// The full set of elements in all arrays.
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llvm::SmallVector<ValueT> values_;
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};
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} // namespace Carbon
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#endif // CARBON_COMMON_ARRAY_STACK_H_
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