[ELF] Reorder SectionBase/InputSectionBase members
[llvm-project.git] / clang-tools-extra / clangd / CodeComplete.h
blobbb2ebd94786455abbb576212c5a6aa81eba00398
1 //===--- CodeComplete.h ------------------------------------------*- C++-*-===//
2 //
3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4 // See https://llvm.org/LICENSE.txt for license information.
5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6 //
7 //===----------------------------------------------------------------------===//
8 //
9 // Code completion provides suggestions for what the user might type next.
10 // After "std::string S; S." we might suggest members of std::string.
11 // Signature help describes the parameters of a function as you type them.
13 //===----------------------------------------------------------------------===//
15 #ifndef LLVM_CLANG_TOOLS_EXTRA_CLANGD_CODECOMPLETE_H
16 #define LLVM_CLANG_TOOLS_EXTRA_CLANGD_CODECOMPLETE_H
18 #include "ASTSignals.h"
19 #include "Compiler.h"
20 #include "Config.h"
21 #include "Protocol.h"
22 #include "Quality.h"
23 #include "index/Index.h"
24 #include "index/Symbol.h"
25 #include "index/SymbolOrigin.h"
26 #include "support/Markup.h"
27 #include "support/Path.h"
28 #include "clang/Sema/CodeCompleteConsumer.h"
29 #include "clang/Sema/CodeCompleteOptions.h"
30 #include "llvm/ADT/SmallVector.h"
31 #include "llvm/ADT/StringRef.h"
32 #include <functional>
33 #include <future>
34 #include <optional>
35 #include <utility>
37 namespace clang {
38 class NamedDecl;
39 namespace clangd {
40 struct PreambleData;
41 struct CodeCompletion;
43 struct CodeCompleteOptions {
44 /// Returns options that can be passed to clang's completion engine.
45 clang::CodeCompleteOptions getClangCompleteOpts() const;
47 /// When true, completion items will contain expandable code snippets in
48 /// completion (e.g. `return ${1:expression}` or `foo(${1:int a}, ${2:int
49 /// b})).
50 bool EnableSnippets = false;
52 /// Include results that are not legal completions in the current context.
53 /// For example, private members are usually inaccessible.
54 bool IncludeIneligibleResults = false;
56 /// Force sema to load decls from preamble even if an index is provided.
57 /// This is helpful for cases the index can't provide symbols, e.g. with
58 /// experimental c++20 modules
59 bool ForceLoadPreamble = false;
61 /// Combine overloads into a single completion item where possible.
62 /// If none, the implementation may choose an appropriate behavior.
63 /// (In practice, ClangdLSPServer enables bundling if the client claims
64 /// to supports signature help).
65 std::optional<bool> BundleOverloads;
67 /// Limit the number of results returned (0 means no limit).
68 /// If more results are available, we set CompletionList.isIncomplete.
69 size_t Limit = 0;
71 /// Whether to present doc comments as plain-text or markdown.
72 MarkupKind DocumentationFormat = MarkupKind::PlainText;
74 enum IncludeInsertion {
75 IWYU,
76 NeverInsert,
77 } InsertIncludes = IncludeInsertion::IWYU;
79 /// Whether include insertions for Objective-C code should use #import instead
80 /// of #include.
81 bool ImportInsertions = false;
83 /// A visual indicator to prepend to the completion label to indicate whether
84 /// completion result would trigger an #include insertion or not.
85 struct IncludeInsertionIndicator {
86 std::string Insert = "•";
87 std::string NoInsert = " ";
88 } IncludeIndicator;
90 /// Expose origins of completion items in the label (for debugging).
91 bool ShowOrigins = false;
93 // Populated internally by clangd, do not set.
94 /// If `Index` is set, it is used to augment the code completion
95 /// results.
96 /// FIXME(ioeric): we might want a better way to pass the index around inside
97 /// clangd.
98 const SymbolIndex *Index = nullptr;
100 const ASTSignals *MainFileSignals = nullptr;
101 /// Include completions that require small corrections, e.g. change '.' to
102 /// '->' on member access etc.
103 bool IncludeFixIts = false;
105 /// Whether to include index symbols that are not defined in the scopes
106 /// visible from the code completion point. This applies in contexts without
107 /// explicit scope qualifiers.
109 /// Such completions can insert scope qualifiers.
110 bool AllScopes = false;
112 /// The way argument list on calls '()' and generics '<>' are handled.
113 Config::ArgumentListsPolicy ArgumentLists =
114 Config::ArgumentListsPolicy::FullPlaceholders;
116 /// Whether to use the clang parser, or fallback to text-based completion
117 /// (using identifiers in the current file and symbol indexes).
118 enum CodeCompletionParse {
119 /// Block until we can run the parser (e.g. preamble is built).
120 /// Return an error if this fails.
121 AlwaysParse,
122 /// Run the parser if inputs (preamble) are ready.
123 /// Otherwise, use text-based completion.
124 ParseIfReady,
125 /// Always use text-based completion.
126 NeverParse,
127 } RunParser = ParseIfReady;
129 /// Callback invoked on all CompletionCandidate after they are scored and
130 /// before they are ranked (by -Score). Thus the results are yielded in
131 /// arbitrary order.
133 /// This callbacks allows capturing various internal structures used by clangd
134 /// during code completion. Eg: Symbol quality and relevance signals.
135 std::function<void(const CodeCompletion &, const SymbolQualitySignals &,
136 const SymbolRelevanceSignals &, float Score)>
137 RecordCCResult;
139 /// Model to use for ranking code completion candidates.
140 enum CodeCompletionRankingModel {
141 Heuristics,
142 DecisionForest,
144 static const CodeCompletionRankingModel DefaultRankingModel;
145 CodeCompletionRankingModel RankingModel = DefaultRankingModel;
147 /// Callback used to score a CompletionCandidate if DecisionForest ranking
148 /// model is enabled.
149 /// This allows us to inject experimental models and compare them with
150 /// baseline model using A/B testing.
151 std::function<DecisionForestScores(
152 const SymbolQualitySignals &, const SymbolRelevanceSignals &, float Base)>
153 DecisionForestScorer = &evaluateDecisionForest;
154 /// Weight for combining NameMatch and Prediction of DecisionForest.
155 /// CompletionScore is NameMatch * pow(Base, Prediction).
156 /// The optimal value of Base largely depends on the semantics of the model
157 /// and prediction score (e.g. algorithm used during training, number of
158 /// trees, etc.). Usually if the range of Prediction is [-20, 20] then a Base
159 /// in [1.2, 1.7] works fine.
160 /// Semantics: E.g. For Base = 1.3, if the Prediction score reduces by 2.6
161 /// points then completion score reduces by 50% or 1.3^(-2.6).
162 float DecisionForestBase = 1.3f;
165 // Semi-structured representation of a code-complete suggestion for our C++ API.
166 // We don't use the LSP structures here (unlike most features) as we want
167 // to expose more data to allow for more precise testing and evaluation.
168 struct CodeCompletion {
169 // The unqualified name of the symbol or other completion item.
170 std::string Name;
171 // The name of the symbol for filtering and sorting purposes. Typically the
172 // same as `Name`, but may be different e.g. for ObjC methods, `Name` is the
173 // first selector fragment but the `FilterText` is the entire selector.
174 std::string FilterText;
175 // The scope qualifier for the symbol name. e.g. "ns1::ns2::"
176 // Empty for non-symbol completions. Not inserted, but may be displayed.
177 std::string Scope;
178 // Text that must be inserted before the name, and displayed (e.g. base::).
179 std::string RequiredQualifier;
180 // Details to be displayed following the name. Not inserted.
181 std::string Signature;
182 // Text to be inserted following the name, in snippet format.
183 std::string SnippetSuffix;
184 // Type to be displayed for this completion.
185 std::string ReturnType;
186 // The parsed documentation comment.
187 std::optional<markup::Document> Documentation;
188 CompletionItemKind Kind = CompletionItemKind::Missing;
189 // This completion item may represent several symbols that can be inserted in
190 // the same way, such as function overloads. In this case BundleSize > 1, and
191 // the following fields are summaries:
192 // - Signature is e.g. "(...)" for functions.
193 // - SnippetSuffix is similarly e.g. "(${0})".
194 // - ReturnType may be empty
195 // - Documentation may be from one symbol, or a combination of several
196 // Other fields should apply equally to all bundled completions.
197 unsigned BundleSize = 1;
198 SymbolOrigin Origin = SymbolOrigin::Unknown;
200 struct IncludeCandidate {
201 // The header through which this symbol could be included.
202 // Quoted string as expected by an #include directive, e.g. "<memory>".
203 // Empty for non-symbol completions, or when not known.
204 std::string Header;
205 // Present if Header should be inserted to use this item.
206 std::optional<TextEdit> Insertion;
208 // All possible include headers ranked by preference. By default, the first
209 // include is used.
210 // If we've bundled together overloads that have different sets of includes,
211 // thse includes may not be accurate for all of them.
212 llvm::SmallVector<IncludeCandidate, 1> Includes;
214 /// Holds information about small corrections that needs to be done. Like
215 /// converting '->' to '.' on member access.
216 std::vector<TextEdit> FixIts;
218 /// Holds the range of the token we are going to replace with this completion.
219 Range CompletionTokenRange;
221 // Scores are used to rank completion items.
222 struct Scores {
223 // The score that items are ranked by.
224 float Total = 0.f;
226 // The finalScore with the fuzzy name match score excluded.
227 // When filtering client-side, editors should calculate the new fuzzy score,
228 // whose scale is 0-1 (with 1 = prefix match, special case 2 = exact match),
229 // and recompute finalScore = fuzzyScore * symbolScore.
230 float ExcludingName = 0.f;
232 // Component scores that contributed to the final score:
234 // Quality describes how important we think this candidate is,
235 // independent of the query.
236 // e.g. symbols with lots of incoming references have higher quality.
237 float Quality = 0.f;
238 // Relevance describes how well this candidate matched the query.
239 // e.g. symbols from nearby files have higher relevance.
240 float Relevance = 0.f;
242 Scores Score;
244 /// Indicates if this item is deprecated.
245 bool Deprecated = false;
247 // Serialize this to an LSP completion item. This is a lossy operation.
248 CompletionItem render(const CodeCompleteOptions &) const;
250 raw_ostream &operator<<(raw_ostream &, const CodeCompletion &);
251 struct CodeCompleteResult {
252 std::vector<CodeCompletion> Completions;
253 bool HasMore = false;
254 CodeCompletionContext::Kind Context = CodeCompletionContext::CCC_Other;
255 // The text that is being directly completed.
256 // Example: foo.pb^ -> foo.push_back()
257 // ~~
258 // Typically matches the textEdit.range of Completions, but not guaranteed to.
259 std::optional<Range> CompletionRange;
260 // Usually the source will be parsed with a real C++ parser.
261 // But heuristics may be used instead if e.g. the preamble is not ready.
262 bool RanParser = true;
264 raw_ostream &operator<<(raw_ostream &, const CodeCompleteResult &);
266 /// A speculative and asynchronous fuzzy find index request (based on cached
267 /// request) that can be sent before parsing sema. This would reduce completion
268 /// latency if the speculation succeeds.
269 struct SpeculativeFuzzyFind {
270 /// A cached request from past code completions.
271 /// Set by caller of `codeComplete()`.
272 std::optional<FuzzyFindRequest> CachedReq;
273 /// The actual request used by `codeComplete()`.
274 /// Set by `codeComplete()`. This can be used by callers to update cache.
275 std::optional<FuzzyFindRequest> NewReq;
276 /// The result is consumed by `codeComplete()` if speculation succeeded.
277 /// NOTE: the destructor will wait for the async call to finish.
278 std::future<std::pair<bool /*Incomplete*/, SymbolSlab>> Result;
281 /// Gets code completions at a specified \p Pos in \p FileName.
283 /// If \p Preamble is nullptr, this runs code completion without compiling the
284 /// code.
286 /// If \p SpecFuzzyFind is set, a speculative and asynchronous fuzzy find index
287 /// request (based on cached request) will be run before parsing sema. In case
288 /// the speculative result is used by code completion (e.g. speculation failed),
289 /// the speculative result is not consumed, and `SpecFuzzyFind` is only
290 /// destroyed when the async request finishes.
291 CodeCompleteResult codeComplete(PathRef FileName, Position Pos,
292 const PreambleData *Preamble,
293 const ParseInputs &ParseInput,
294 CodeCompleteOptions Opts,
295 SpeculativeFuzzyFind *SpecFuzzyFind = nullptr);
297 /// Get signature help at a specified \p Pos in \p FileName.
298 SignatureHelp signatureHelp(PathRef FileName, Position Pos,
299 const PreambleData &Preamble,
300 const ParseInputs &ParseInput,
301 MarkupKind DocumentationFormat);
303 // For index-based completion, we only consider:
304 // * symbols in namespaces or translation unit scopes (e.g. no class
305 // members, no locals)
306 // * enum constants (both scoped and unscoped)
307 // * primary templates (no specializations)
308 // For the other cases, we let Clang do the completion because it does not
309 // need any non-local information and it will be much better at following
310 // lookup rules. Other symbols still appear in the index for other purposes,
311 // like workspace/symbols or textDocument/definition, but are not used for code
312 // completion.
313 bool isIndexedForCodeCompletion(const NamedDecl &ND, ASTContext &ASTCtx);
315 // Text immediately before the completion point that should be completed.
316 // This is heuristically derived from the source code, and is used when:
317 // - semantic analysis fails
318 // - semantic analysis may be slow, and we speculatively query the index
319 struct CompletionPrefix {
320 // The unqualified partial name.
321 // If there is none, begin() == end() == completion position.
322 llvm::StringRef Name;
323 // The spelled scope qualifier, such as Foo::.
324 // If there is none, begin() == end() == Name.begin().
325 llvm::StringRef Qualifier;
327 // Heuristically parses before Offset to determine what should be completed.
328 CompletionPrefix guessCompletionPrefix(llvm::StringRef Content,
329 unsigned Offset);
331 // Whether it makes sense to complete at the point based on typed characters.
332 // For instance, we implicitly trigger at `a->^` but not at `a>^`.
333 bool allowImplicitCompletion(llvm::StringRef Content, unsigned Offset);
335 } // namespace clangd
336 } // namespace clang
338 #endif // LLVM_CLANG_TOOLS_EXTRA_CLANGD_CODECOMPLETE_H