1//===--- Symbol.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#ifndef LLVM_CLANG_TOOLS_EXTRA_CLANGD_INDEX_SYMBOL_H
10#define LLVM_CLANG_TOOLS_EXTRA_CLANGD_INDEX_SYMBOL_H
11
12#include "index/SymbolID.h"
13#include "index/SymbolLocation.h"
14#include "index/SymbolOrigin.h"
15#include "clang/Index/IndexSymbol.h"
16#include "llvm/ADT/BitmaskEnum.h"
17#include "llvm/ADT/StringRef.h"
18#include "llvm/Support/StringSaver.h"
19
20namespace clang {
21namespace clangd {
22
23LLVM_ENABLE_BITMASK_ENUMS_IN_NAMESPACE();
24
25/// The class presents a C++ symbol, e.g. class, function.
26///
27/// WARNING: Symbols do not own much of their underlying data - typically
28/// strings are owned by a SymbolSlab. They should be treated as non-owning
29/// references. Copies are shallow.
30///
31/// When adding new unowned data fields to Symbol, remember to update:
32/// - SymbolSlab::Builder in Index.cpp, to copy them to the slab's storage.
33/// - mergeSymbol in Merge.cpp, to properly combine two Symbols.
34///
35/// A fully documented symbol can be split as:
36/// size_type std::map<k, t>::count(const K& key) const
37/// | Return | Scope |Name| Signature |
38/// We split up these components to allow display flexibility later.
39struct Symbol {
40 /// The ID of the symbol.
41 SymbolID ID;
42 /// The symbol information, like symbol kind.
43 index::SymbolInfo SymInfo = index::SymbolInfo();
44 /// The unqualified name of the symbol, e.g. "bar" (for ns::bar).
45 llvm::StringRef Name;
46 /// The containing namespace. e.g. "" (global), "ns::" (top-level namespace).
47 llvm::StringRef Scope;
48 /// The location of the symbol's definition, if one was found.
49 /// This just covers the symbol name (e.g. without class/function body).
50 SymbolLocation Definition;
51 /// The location of the preferred declaration of the symbol.
52 /// This just covers the symbol name.
53 /// This may be the same as Definition.
54 ///
55 /// A C++ symbol may have multiple declarations, and we pick one to prefer.
56 /// * For classes, the canonical declaration should be the definition.
57 /// * For non-inline functions, the canonical declaration typically appears
58 /// in the ".h" file corresponding to the definition.
59 SymbolLocation CanonicalDeclaration;
60 /// The number of translation units that reference this symbol from their main
61 /// file. This number is only meaningful if aggregated in an index.
62 unsigned References = 0;
63 /// Where this symbol came from. Usually an index provides a constant value.
64 SymbolOrigin Origin = SymbolOrigin::Unknown;
65 /// A brief description of the symbol that can be appended in the completion
66 /// candidate list. For example, "(X x, Y y) const" is a function signature.
67 /// Only set when the symbol is indexed for completion.
68 llvm::StringRef Signature;
69 /// Argument list in human-readable format, will be displayed to help
70 /// disambiguate between different specializations of a template. Empty for
71 /// non-specializations. Example: "<int, bool, 3>"
72 llvm::StringRef TemplateSpecializationArgs;
73 /// What to insert when completing this symbol, after the symbol name.
74 /// This is in LSP snippet syntax (e.g. "({$0})" for a no-args function).
75 /// (When snippets are disabled, the symbol name alone is used).
76 /// Only set when the symbol is indexed for completion.
77 llvm::StringRef CompletionSnippetSuffix;
78 /// Documentation including comment for the symbol declaration.
79 llvm::StringRef Documentation;
80 /// Type when this symbol is used in an expression. (Short display form).
81 /// e.g. return type of a function, or type of a variable.
82 /// Only set when the symbol is indexed for completion.
83 llvm::StringRef ReturnType;
84
85 /// Raw representation of the OpaqueType of the symbol, used for scoring
86 /// purposes.
87 /// Only set when the symbol is indexed for completion.
88 llvm::StringRef Type;
89
90 enum IncludeDirective : uint8_t {
91 Invalid = 0,
92 /// `#include "header.h"`
93 Include = 1,
94 /// `#import "header.h"`
95 Import = 2,
96
97 LLVM_MARK_AS_BITMASK_ENUM(Import)
98 };
99
100 struct IncludeHeaderWithReferences {
101 IncludeHeaderWithReferences() = default;
102
103 IncludeHeaderWithReferences(llvm::StringRef IncludeHeader,
104 uint32_t References,
105 IncludeDirective SupportedDirectives)
106 : IncludeHeader(IncludeHeader), References(References),
107 SupportedDirectives(SupportedDirectives) {}
108
109 /// This can be either a URI of the header to be #include'd
110 /// for this symbol, or a literal header quoted with <> or "" that is
111 /// suitable to be included directly. When it is a URI, the exact #include
112 /// path needs to be calculated according to the URI scheme.
113 ///
114 /// Note that the include header is a canonical include for the symbol and
115 /// can be different from FileURI in the CanonicalDeclaration.
116 llvm::StringRef IncludeHeader = "";
117 /// The number of translation units that reference this symbol and include
118 /// this header. This number is only meaningful if aggregated in an index.
119 uint32_t References : 30;
120 /// Bitfield of supported directives (IncludeDirective) that can be used
121 /// when including this header.
122 uint32_t SupportedDirectives : 2;
123
124 IncludeDirective supportedDirectives() const {
125 return static_cast<IncludeDirective>(SupportedDirectives);
126 }
127 };
128 /// One Symbol can potentially be included via different headers.
129 /// - If we haven't seen a definition, this covers all declarations.
130 /// - If we have seen a definition, this covers declarations visible from
131 /// any definition.
132 /// Only set when the symbol is indexed for completion.
133 llvm::SmallVector<IncludeHeaderWithReferences, 1> IncludeHeaders;
134
135 enum SymbolFlag : uint8_t {
136 None = 0,
137 /// Whether or not this symbol is meant to be used for the code completion.
138 /// See also isIndexedForCodeCompletion().
139 /// Note that we don't store completion information (signature, snippet,
140 /// type, includes) if the symbol is not indexed for code completion.
141 IndexedForCodeCompletion = 1 << 0,
142 /// Indicates if the symbol is deprecated.
143 Deprecated = 1 << 1,
144 /// Symbol is an implementation detail.
145 ImplementationDetail = 1 << 2,
146 /// Symbol is visible to other files (not e.g. a static helper function).
147 VisibleOutsideFile = 1 << 3,
148 /// Symbol has an attached documentation comment.
149 HasDocComment = 1 << 4
150 };
151 SymbolFlag Flags = SymbolFlag::None;
152
153 /// FIXME: also add deprecation message and fixit?
154};
155
156inline Symbol::SymbolFlag operator|(Symbol::SymbolFlag A,
157 Symbol::SymbolFlag B) {
158 return static_cast<Symbol::SymbolFlag>(static_cast<uint8_t>(A) |
159 static_cast<uint8_t>(B));
160}
161inline Symbol::SymbolFlag &operator|=(Symbol::SymbolFlag &A,
162 Symbol::SymbolFlag B) {
163 return A = A | B;
164}
165
166llvm::raw_ostream &operator<<(llvm::raw_ostream &OS, const Symbol &S);
167llvm::raw_ostream &operator<<(llvm::raw_ostream &OS, Symbol::SymbolFlag);
168
169/// Invokes Callback with each StringRef& contained in the Symbol.
170/// Useful for deduplicating backing strings.
171template <typename Callback> void visitStrings(Symbol &S, const Callback &CB) {
172 CB(S.Name);
173 CB(S.Scope);
174 CB(S.TemplateSpecializationArgs);
175 CB(S.Signature);
176 CB(S.CompletionSnippetSuffix);
177 CB(S.Documentation);
178 CB(S.ReturnType);
179 CB(S.Type);
180 auto RawCharPointerCB = [&CB](const char *&P) {
181 llvm::StringRef S(P);
182 CB(S);
183 assert(!S.data()[S.size()] && "Visited StringRef must be null-terminated");
184 P = S.data();
185 };
186 RawCharPointerCB(S.CanonicalDeclaration.FileURI);
187 RawCharPointerCB(S.Definition.FileURI);
188
189 for (auto &Include : S.IncludeHeaders)
190 CB(Include.IncludeHeader);
191}
192
193/// Computes query-independent quality score for a Symbol.
194/// This currently falls in the range [1, ln(#indexed documents)].
195/// FIXME: this should probably be split into symbol -> signals
196/// and signals -> score, so it can be reused for Sema completions.
197float quality(const Symbol &S);
198
199/// An immutable symbol container that stores a set of symbols.
200/// The container will maintain the lifetime of the symbols.
201class SymbolSlab {
202public:
203 using const_iterator = std::vector<Symbol>::const_iterator;
204 using iterator = const_iterator;
205 using value_type = Symbol;
206
207 SymbolSlab() = default;
208
209 const_iterator begin() const { return Symbols.begin(); }
210 const_iterator end() const { return Symbols.end(); }
211 const_iterator find(const SymbolID &SymID) const;
212
213 using size_type = size_t;
214 size_type size() const { return Symbols.size(); }
215 bool empty() const { return Symbols.empty(); }
216 // Estimates the total memory usage.
217 size_t bytes() const {
218 return sizeof(*this) + Arena.getTotalMemory() +
219 Symbols.capacity() * sizeof(Symbol);
220 }
221
222 /// SymbolSlab::Builder is a mutable container that can 'freeze' to
223 /// SymbolSlab. The frozen SymbolSlab will use less memory.
224 class Builder {
225 public:
226 Builder() : UniqueStrings(Arena) {}
227
228 /// Adds a symbol, overwriting any existing one with the same ID.
229 /// This is a deep copy: underlying strings will be owned by the slab.
230 void insert(const Symbol &S);
231
232 /// Removes the symbol with an ID, if it exists.
233 void erase(const SymbolID &ID) { Symbols.erase(Val: ID); }
234
235 /// Returns the symbol with an ID, if it exists. Valid until insert/remove.
236 const Symbol *find(const SymbolID &ID) {
237 auto I = Symbols.find(Val: ID);
238 return I == Symbols.end() ? nullptr : &I->second;
239 }
240
241 /// Consumes the builder to finalize the slab.
242 SymbolSlab build() &&;
243
244 private:
245 llvm::BumpPtrAllocator Arena;
246 /// Intern table for strings. Contents are on the arena.
247 llvm::UniqueStringSaver UniqueStrings;
248 /// Values are indices into Symbols vector.
249 llvm::DenseMap<SymbolID, Symbol> Symbols;
250 };
251
252private:
253 SymbolSlab(llvm::BumpPtrAllocator Arena, std::vector<Symbol> Symbols)
254 : Arena(std::move(Arena)), Symbols(std::move(Symbols)) {}
255
256 llvm::BumpPtrAllocator Arena; // Owns Symbol data that the Symbols do not.
257 std::vector<Symbol> Symbols; // Sorted by SymbolID to allow lookup.
258};
259
260llvm::raw_ostream &operator<<(llvm::raw_ostream &OS, const SymbolSlab &Slab);
261
262} // namespace clangd
263} // namespace clang
264
265#endif // LLVM_CLANG_TOOLS_EXTRA_CLANGD_INDEX_SYMBOL_H
266

source code of clang-tools-extra/clangd/index/Symbol.h