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https://github.com/carbon-language/carbon-lang.git
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Richard Smith
c78751338b
Add support for "jump to declaration", "find references", type information on hover. This support is strictly single-file for now; only references and declarations within the same file are found. We could go a bit beyond that, but to properly handle cross-file references we'll need to build an index and a compilation database, which is beyond the scope of this change. On hover, we provide the type information for the instruction under the cursor as-is. This is frequently not very useful, as the type of a function F is simply "<type of F>", but is a starting point for richer information. Assisted-by: Claude Code
70 lines
3.1 KiB
C++
70 lines
3.1 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_TOOLCHAIN_LANGUAGE_SERVER_SEM_IR_INDEX_H_
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#define CARBON_TOOLCHAIN_LANGUAGE_SERVER_SEM_IR_INDEX_H_
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#include "llvm/ADT/ArrayRef.h"
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#include "llvm/ADT/SmallVector.h"
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#include "toolchain/lex/token_index.h"
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#include "toolchain/lex/tokenized_buffer.h"
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#include "toolchain/parse/node_ids.h"
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#include "toolchain/parse/tree_and_subtrees.h"
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#include "toolchain/sem_ir/file.h"
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namespace Carbon::LanguageServer {
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// Returns the token that identifies `node_id`: the name it declares, if it
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// declares one, and otherwise the node's own token.
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//
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// A declaration's own token is wherever the parser finished it -- the `{` of a
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// function body, or the `:` of a binding -- which is not what a user points at
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// to mean that declaration. Requests are answered at the name instead, so both
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// the index and the locations we report are keyed on it.
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auto GetNameToken(const Parse::TreeAndSubtrees& tree_and_subtrees,
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Parse::NodeId node_id) -> Lex::TokenIndex;
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// Maps each token to the instructions that were checked from it.
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//
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// Position-based requests such as `hover` and `definition` all start from a
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// source position, so this is keyed by token rather than by parse node: the
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// caller has to find the token for a position anyway, and the parse node is
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// recoverable from an instruction's `LocId`. Instructions imported from other
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// files are excluded, because their locations refer to another file's parse
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// tree rather than to a token in this one.
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//
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// Build this lazily, on the first query after the file's text changes. Building
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// costs the same single pass over the instructions that an unindexed scan
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// would, and most text changes are never followed by a query, so building
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// eagerly would only add work to the latency-sensitive path that produces
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// diagnostics.
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class SemIRIndex {
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public:
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explicit SemIRIndex(const SemIR::File& sem_ir,
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const Parse::TreeAndSubtrees& tree_and_subtrees);
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// Returns the instructions checked from `token`, in `InstId` order. Returns
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// an empty list for a token that produced no instructions, which is common:
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// punctuation and keywords usually contribute to an enclosing instruction
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// rather than producing one of their own.
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auto InstsForToken(Lex::TokenIndex token) const
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-> llvm::ArrayRef<SemIR::InstId>;
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private:
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// Instructions grouped by token, in the compressed-sparse-row layout: the
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// group for token `i` is `insts_[token_starts_[i] .. token_starts_[i + 1])`.
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// `token_starts_` therefore has one more entry than there are tokens.
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//
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// Token indices are dense, so this is built by counting sort in a single pass
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// over the instructions, and looked up in constant time. A hash map would
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// need to handle the many-instructions-per-token case explicitly; here it
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// falls out of the layout.
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llvm::SmallVector<SemIR::InstId, 0> insts_;
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llvm::SmallVector<int32_t, 0> token_starts_;
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};
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} // namespace Carbon::LanguageServer
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#endif // CARBON_TOOLCHAIN_LANGUAGE_SERVER_SEM_IR_INDEX_H_
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