mirror of
https://github.com/carbon-language/carbon-lang.git
synced 2026-10-04 13:11:04 +01:00
Richard Smith
b300f36e6f
This fixes various violations of C++'s One Definition Rule, where we accidentally gave the same static data member multiple definitions in different translation units. Clang happens to emit such definitions with weak linkage, which allows us to get away with this without link errors, but it's still formally incorrect. Also switch keyword order around for a handful of instances of `constexpr inline`, per agreement in open discussion. This happens to reduce the size of a `-c dbg` toolchain binary by 7.2 MiB, presumably by making more of our symbols and especially debug info discardable.
64 lines
2.4 KiB
C++
64 lines
2.4 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_TOOLCHAIN_LEX_TOKEN_INDEX_H_
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#define CARBON_TOOLCHAIN_LEX_TOKEN_INDEX_H_
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#include "toolchain/base/index_base.h"
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#include "toolchain/lex/token_kind.h"
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namespace Carbon::Lex {
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class TokenInfo;
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// A lightweight handle to a lexed token in a `TokenizedBuffer`.
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//
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// `TokenIndex` objects are designed to be passed by value, not reference or
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// pointer. They are also designed to be small and efficient to store in data
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// structures.
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//
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// `TokenIndex` objects from the same `TokenizedBuffer` can be compared with
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// each other, both for being the same token within the buffer, and to establish
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// relative position within the token stream that has been lexed out of the
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// buffer. `TokenIndex` objects from different `TokenizedBuffer`s cannot be
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// meaningfully compared.
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//
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// All other APIs to query a `TokenIndex` are on the `TokenizedBuffer`.
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struct TokenIndex : public IndexBase<TokenIndex> {
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// The number of bits which must be allotted for `TokenIndex`.
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static constexpr int Bits = 23;
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// The maximum number of tokens that can be stored, including the FileStart
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// and FileEnd tokens. Exceeding this is diagnosed by `TooManyTokens`.
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static constexpr int Max = 1 << Bits;
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static constexpr llvm::StringLiteral Label = "token";
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static const TokenIndex None;
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// Comments aren't tokenized, so this is the first token after FileStart.
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static const TokenIndex FirstNonCommentToken;
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using IndexBase::IndexBase;
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};
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inline constexpr TokenIndex TokenIndex::None(TokenIndex::NoneIndex);
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inline constexpr TokenIndex TokenIndex::FirstNonCommentToken(1);
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// A lightweight handle to a lexed token in a `TokenizedBuffer` whose kind is
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// known to be `Kind`.
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template <const TokenKind& K>
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struct TokenIndexForKind : public TokenIndex {
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// NOLINTNEXTLINE(readability-identifier-naming)
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static const TokenKind& Kind;
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constexpr explicit TokenIndexForKind(TokenIndex index) : TokenIndex(index) {}
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};
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template <const TokenKind& K>
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const TokenKind& TokenIndexForKind<K>::Kind = K;
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#define CARBON_TOKEN(TokenName) \
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using TokenName##TokenIndex = TokenIndexForKind<TokenKind::TokenName>;
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#include "toolchain/lex/token_kind.def"
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} // namespace Carbon::Lex
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#endif // CARBON_TOOLCHAIN_LEX_TOKEN_INDEX_H_
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