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4845f40dff
This switches `DCHECK` and `FATAL` as well. The goal is to reduce the code size impact of these assertions so that we can keep more of them enabled. Currently, the largest cost I see from `CHECK` is not the actual check or the cold code itself, but actually the failure to inline trivial functions due to the presence of the cold code. This means that our goal isn't to reduce apparent code size in the final binary but the LLVM IR cost assessed for these routines in the inliner, which closely correlates with code size but is a bit different. As discussed in #4283, experimentation shows that a single function call with a minimal number of arguments is the lowest cost model for these. This is easily achieved with a format-string API that internally uses `llvm::formatv`. This PR is essentially the `CHECK` version of #4283. However, the check macros are substantially harder to make work with both format strings and streaming because they also take a condition. Also, unexpectedly, I was very successful at devising a regular expression based automated rewrite from the streaming to the format string form with only low 10s of manual fixes. This includes compacting strings broken up across lines, etc. Given how well that went, I've prepared this PR which just directly switches to the format string API and migrate everything to use it. One nice side-effect is that the format string approach ends up greatly simplifying the implementation here as well. This is ... *shockingly* effective. Parsing speeds up by more than 3% with just this change. And checking speeds up by **8%** with this change alone: ``` BM_CompileAPIFileDenseDecls<Phase::Parse>/256 86.3µs ± 1% 82.9µs ± 1% -3.94% (p=0.000 n=17+19) BM_CompileAPIFileDenseDecls<Phase::Parse>/1024 431µs ± 1% 415µs ± 1% -3.76% (p=0.000 n=18+19) BM_CompileAPIFileDenseDecls<Phase::Parse>/4096 1.77ms ± 1% 1.71ms ± 1% -3.18% (p=0.000 n=18+19) BM_CompileAPIFileDenseDecls<Phase::Parse>/16384 7.44ms ± 1% 7.17ms ± 2% -3.56% (p=0.000 n=18+20) BM_CompileAPIFileDenseDecls<Phase::Parse>/65536 30.7ms ± 1% 29.7ms ± 1% -3.15% (p=0.000 n=18+20) BM_CompileAPIFileDenseDecls<Phase::Parse>/262144 131ms ± 1% 127ms ± 1% -2.81% (p=0.000 n=18+18) BM_CompileAPIFileDenseDecls<Phase::Check>/256 878µs ± 2% 800µs ± 1% -8.91% (p=0.000 n=19+20) BM_CompileAPIFileDenseDecls<Phase::Check>/1024 1.88ms ± 2% 1.72ms ± 1% -8.56% (p=0.000 n=19+20) BM_CompileAPIFileDenseDecls<Phase::Check>/4096 5.78ms ± 2% 5.28ms ± 1% -8.70% (p=0.000 n=20+18) BM_CompileAPIFileDenseDecls<Phase::Check>/16384 21.9ms ± 1% 20.1ms ± 1% -8.02% (p=0.000 n=18+20) BM_CompileAPIFileDenseDecls<Phase::Check>/65536 90.4ms ± 2% 83.1ms ± 1% -8.04% (p=0.000 n=19+20) BM_CompileAPIFileDenseDecls<Phase::Check>/262144 381ms ± 2% 352ms ± 1% -7.79% (p=0.000 n=19+19) ``` --------- Co-authored-by: Richard Smith <richard@metafoo.co.uk> Co-authored-by: josh11b <15258583+josh11b@users.noreply.github.com>
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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