clang-tools  10.0.0git
CodeComplete.cpp
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1 //===--- CodeComplete.cpp ----------------------------------------*- 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 has several moving parts:
10 // - AST-based completions are provided using the completion hooks in Sema.
11 // - external completions are retrieved from the index (using hints from Sema)
12 // - the two sources overlap, and must be merged and overloads bundled
13 // - results must be scored and ranked (see Quality.h) before rendering
14 //
15 // Signature help works in a similar way as code completion, but it is simpler:
16 // it's purely AST-based, and there are few candidates.
17 //
18 //===----------------------------------------------------------------------===//
19 
20 #include "CodeComplete.h"
21 #include "AST.h"
22 #include "CodeCompletionStrings.h"
23 #include "Compiler.h"
24 #include "Diagnostics.h"
25 #include "ExpectedTypes.h"
26 #include "FileDistance.h"
27 #include "FuzzyMatch.h"
28 #include "Headers.h"
29 #include "Logger.h"
30 #include "Preamble.h"
31 #include "Protocol.h"
32 #include "Quality.h"
33 #include "SourceCode.h"
34 #include "TUScheduler.h"
35 #include "Threading.h"
36 #include "Trace.h"
37 #include "URI.h"
38 #include "index/Index.h"
39 #include "index/Symbol.h"
40 #include "index/SymbolOrigin.h"
41 #include "clang/AST/Decl.h"
42 #include "clang/AST/DeclBase.h"
43 #include "clang/Basic/CharInfo.h"
44 #include "clang/Basic/LangOptions.h"
45 #include "clang/Basic/SourceLocation.h"
46 #include "clang/Format/Format.h"
47 #include "clang/Frontend/CompilerInstance.h"
48 #include "clang/Frontend/FrontendActions.h"
49 #include "clang/Lex/ExternalPreprocessorSource.h"
50 #include "clang/Lex/Preprocessor.h"
51 #include "clang/Lex/PreprocessorOptions.h"
52 #include "clang/Sema/CodeCompleteConsumer.h"
53 #include "clang/Sema/DeclSpec.h"
54 #include "clang/Sema/Sema.h"
55 #include "llvm/ADT/ArrayRef.h"
56 #include "llvm/ADT/None.h"
57 #include "llvm/ADT/Optional.h"
58 #include "llvm/ADT/SmallVector.h"
59 #include "llvm/ADT/StringExtras.h"
60 #include "llvm/ADT/StringRef.h"
61 #include "llvm/Support/Compiler.h"
62 #include "llvm/Support/Debug.h"
63 #include "llvm/Support/Error.h"
64 #include "llvm/Support/Format.h"
65 #include "llvm/Support/FormatVariadic.h"
66 #include "llvm/Support/ScopedPrinter.h"
67 #include <algorithm>
68 #include <iterator>
69 
70 // We log detailed candidate here if you run with -debug-only=codecomplete.
71 #define DEBUG_TYPE "CodeComplete"
72 
73 namespace clang {
74 namespace clangd {
75 namespace {
76 
77 CompletionItemKind toCompletionItemKind(index::SymbolKind Kind) {
78  using SK = index::SymbolKind;
79  switch (Kind) {
80  case SK::Unknown:
82  case SK::Module:
83  case SK::Namespace:
84  case SK::NamespaceAlias:
86  case SK::Macro:
88  case SK::Enum:
90  // FIXME(ioeric): use LSP struct instead of class when it is suppoted in the
91  // protocol.
92  case SK::Struct:
93  case SK::Class:
94  case SK::Protocol:
95  case SK::Extension:
96  case SK::Union:
98  case SK::TypeAlias:
99  // We use the same kind as the VSCode C++ extension.
100  // FIXME: pick a better option when we have one.
102  case SK::Using:
104  case SK::Function:
105  // FIXME(ioeric): this should probably be an operator. This should be fixed
106  // when `Operator` is support type in the protocol.
107  case SK::ConversionFunction:
109  case SK::Variable:
110  case SK::Parameter:
112  case SK::Field:
114  // FIXME(ioeric): use LSP enum constant when it is supported in the protocol.
115  case SK::EnumConstant:
117  case SK::InstanceMethod:
118  case SK::ClassMethod:
119  case SK::StaticMethod:
120  case SK::Destructor:
122  case SK::InstanceProperty:
123  case SK::ClassProperty:
124  case SK::StaticProperty:
126  case SK::Constructor:
128  }
129  llvm_unreachable("Unhandled clang::index::SymbolKind.");
130 }
131 
133 toCompletionItemKind(CodeCompletionResult::ResultKind ResKind,
134  const NamedDecl *Decl,
135  CodeCompletionContext::Kind CtxKind) {
136  if (Decl)
137  return toCompletionItemKind(index::getSymbolInfo(Decl).Kind);
138  if (CtxKind == CodeCompletionContext::CCC_IncludedFile)
140  switch (ResKind) {
141  case CodeCompletionResult::RK_Declaration:
142  llvm_unreachable("RK_Declaration without Decl");
143  case CodeCompletionResult::RK_Keyword:
145  case CodeCompletionResult::RK_Macro:
146  return CompletionItemKind::Text; // unfortunately, there's no 'Macro'
147  // completion items in LSP.
148  case CodeCompletionResult::RK_Pattern:
150  }
151  llvm_unreachable("Unhandled CodeCompletionResult::ResultKind.");
152 }
153 
154 // Identifier code completion result.
155 struct RawIdentifier {
156  llvm::StringRef Name;
157  unsigned References; // # of usages in file.
158 };
159 
160 /// A code completion result, in clang-native form.
161 /// It may be promoted to a CompletionItem if it's among the top-ranked results.
162 struct CompletionCandidate {
163  llvm::StringRef Name; // Used for filtering and sorting.
164  // We may have a result from Sema, from the index, or both.
165  const CodeCompletionResult *SemaResult = nullptr;
166  const Symbol *IndexResult = nullptr;
167  const RawIdentifier *IdentifierResult = nullptr;
168  llvm::SmallVector<llvm::StringRef, 1> RankedIncludeHeaders;
169 
170  // Returns a token identifying the overload set this is part of.
171  // 0 indicates it's not part of any overload set.
172  size_t overloadSet(const CodeCompleteOptions &Opts) const {
173  if (!Opts.BundleOverloads.getValueOr(false))
174  return 0;
175  llvm::SmallString<256> Scratch;
176  if (IndexResult) {
177  switch (IndexResult->SymInfo.Kind) {
178  case index::SymbolKind::ClassMethod:
179  case index::SymbolKind::InstanceMethod:
180  case index::SymbolKind::StaticMethod:
181 #ifndef NDEBUG
182  llvm_unreachable("Don't expect members from index in code completion");
183 #else
184  LLVM_FALLTHROUGH;
185 #endif
186  case index::SymbolKind::Function:
187  // We can't group overloads together that need different #includes.
188  // This could break #include insertion.
189  return llvm::hash_combine(
190  (IndexResult->Scope + IndexResult->Name).toStringRef(Scratch),
191  headerToInsertIfAllowed(Opts).getValueOr(""));
192  default:
193  return 0;
194  }
195  }
196  if (SemaResult) {
197  // We need to make sure we're consistent with the IndexResult case!
198  const NamedDecl *D = SemaResult->Declaration;
199  if (!D || !D->isFunctionOrFunctionTemplate())
200  return 0;
201  {
202  llvm::raw_svector_ostream OS(Scratch);
203  D->printQualifiedName(OS);
204  }
205  return llvm::hash_combine(Scratch,
206  headerToInsertIfAllowed(Opts).getValueOr(""));
207  }
208  assert(IdentifierResult);
209  return 0;
210  }
211 
212  // The best header to include if include insertion is allowed.
213  llvm::Optional<llvm::StringRef>
214  headerToInsertIfAllowed(const CodeCompleteOptions &Opts) const {
215  if (Opts.InsertIncludes == CodeCompleteOptions::NeverInsert ||
216  RankedIncludeHeaders.empty())
217  return None;
218  if (SemaResult && SemaResult->Declaration) {
219  // Avoid inserting new #include if the declaration is found in the current
220  // file e.g. the symbol is forward declared.
221  auto &SM = SemaResult->Declaration->getASTContext().getSourceManager();
222  for (const Decl *RD : SemaResult->Declaration->redecls())
223  if (SM.isInMainFile(SM.getExpansionLoc(RD->getBeginLoc())))
224  return None;
225  }
226  return RankedIncludeHeaders[0];
227  }
228 
229  using Bundle = llvm::SmallVector<CompletionCandidate, 4>;
230 };
231 using ScoredBundle =
232  std::pair<CompletionCandidate::Bundle, CodeCompletion::Scores>;
233 struct ScoredBundleGreater {
234  bool operator()(const ScoredBundle &L, const ScoredBundle &R) {
235  if (L.second.Total != R.second.Total)
236  return L.second.Total > R.second.Total;
237  return L.first.front().Name <
238  R.first.front().Name; // Earlier name is better.
239  }
240 };
241 
242 // Assembles a code completion out of a bundle of >=1 completion candidates.
243 // Many of the expensive strings are only computed at this point, once we know
244 // the candidate bundle is going to be returned.
245 //
246 // Many fields are the same for all candidates in a bundle (e.g. name), and are
247 // computed from the first candidate, in the constructor.
248 // Others vary per candidate, so add() must be called for remaining candidates.
249 struct CodeCompletionBuilder {
250  CodeCompletionBuilder(ASTContext *ASTCtx, const CompletionCandidate &C,
251  CodeCompletionString *SemaCCS,
252  llvm::ArrayRef<std::string> QueryScopes,
253  const IncludeInserter &Includes,
254  llvm::StringRef FileName,
255  CodeCompletionContext::Kind ContextKind,
256  const CodeCompleteOptions &Opts, bool GenerateSnippets)
257  : ASTCtx(ASTCtx), ExtractDocumentation(Opts.IncludeComments),
258  EnableFunctionArgSnippets(Opts.EnableFunctionArgSnippets),
259  GenerateSnippets(GenerateSnippets) {
260  add(C, SemaCCS);
261  if (C.SemaResult) {
262  assert(ASTCtx);
263  Completion.Origin |= SymbolOrigin::AST;
264  Completion.Name = llvm::StringRef(SemaCCS->getTypedText());
265  if (Completion.Scope.empty()) {
266  if ((C.SemaResult->Kind == CodeCompletionResult::RK_Declaration) ||
267  (C.SemaResult->Kind == CodeCompletionResult::RK_Pattern))
268  if (const auto *D = C.SemaResult->getDeclaration())
269  if (const auto *ND = dyn_cast<NamedDecl>(D))
270  Completion.Scope =
272  }
273  Completion.Kind = toCompletionItemKind(
274  C.SemaResult->Kind, C.SemaResult->Declaration, ContextKind);
275  // Sema could provide more info on whether the completion was a file or
276  // folder.
277  if (Completion.Kind == CompletionItemKind::File &&
278  Completion.Name.back() == '/')
279  Completion.Kind = CompletionItemKind::Folder;
280  for (const auto &FixIt : C.SemaResult->FixIts) {
281  Completion.FixIts.push_back(toTextEdit(
282  FixIt, ASTCtx->getSourceManager(), ASTCtx->getLangOpts()));
283  }
284  llvm::sort(Completion.FixIts, [](const TextEdit &X, const TextEdit &Y) {
285  return std::tie(X.range.start.line, X.range.start.character) <
286  std::tie(Y.range.start.line, Y.range.start.character);
287  });
288  Completion.Deprecated |=
289  (C.SemaResult->Availability == CXAvailability_Deprecated);
290  }
291  if (C.IndexResult) {
292  Completion.Origin |= C.IndexResult->Origin;
293  if (Completion.Scope.empty())
294  Completion.Scope = C.IndexResult->Scope;
295  if (Completion.Kind == CompletionItemKind::Missing)
296  Completion.Kind = toCompletionItemKind(C.IndexResult->SymInfo.Kind);
297  if (Completion.Name.empty())
298  Completion.Name = C.IndexResult->Name;
299  // If the completion was visible to Sema, no qualifier is needed. This
300  // avoids unneeded qualifiers in cases like with `using ns::X`.
301  if (Completion.RequiredQualifier.empty() && !C.SemaResult) {
302  llvm::StringRef ShortestQualifier = C.IndexResult->Scope;
303  for (llvm::StringRef Scope : QueryScopes) {
304  llvm::StringRef Qualifier = C.IndexResult->Scope;
305  if (Qualifier.consume_front(Scope) &&
306  Qualifier.size() < ShortestQualifier.size())
307  ShortestQualifier = Qualifier;
308  }
309  Completion.RequiredQualifier = ShortestQualifier;
310  }
311  Completion.Deprecated |= (C.IndexResult->Flags & Symbol::Deprecated);
312  }
313  if (C.IdentifierResult) {
314  Completion.Origin |= SymbolOrigin::Identifier;
315  Completion.Kind = CompletionItemKind::Text;
316  Completion.Name = C.IdentifierResult->Name;
317  }
318 
319  // Turn absolute path into a literal string that can be #included.
320  auto Inserted = [&](llvm::StringRef Header)
321  -> llvm::Expected<std::pair<std::string, bool>> {
322  auto ResolvedDeclaring =
323  URI::resolve(C.IndexResult->CanonicalDeclaration.FileURI, FileName);
324  if (!ResolvedDeclaring)
325  return ResolvedDeclaring.takeError();
326  auto ResolvedInserted = toHeaderFile(Header, FileName);
327  if (!ResolvedInserted)
328  return ResolvedInserted.takeError();
329  auto Spelled = Includes.calculateIncludePath(*ResolvedInserted, FileName);
330  if (!Spelled)
331  return llvm::createStringError(llvm::inconvertibleErrorCode(),
332  "Header not on include path");
333  return std::make_pair(
334  std::move(*Spelled),
335  Includes.shouldInsertInclude(*ResolvedDeclaring, *ResolvedInserted));
336  };
337  bool ShouldInsert = C.headerToInsertIfAllowed(Opts).hasValue();
338  // Calculate include paths and edits for all possible headers.
339  for (const auto &Inc : C.RankedIncludeHeaders) {
340  if (auto ToInclude = Inserted(Inc)) {
341  CodeCompletion::IncludeCandidate Include;
342  Include.Header = ToInclude->first;
343  if (ToInclude->second && ShouldInsert)
344  Include.Insertion = Includes.insert(ToInclude->first);
345  Completion.Includes.push_back(std::move(Include));
346  } else
347  log("Failed to generate include insertion edits for adding header "
348  "(FileURI='{0}', IncludeHeader='{1}') into {2}: {3}",
349  C.IndexResult->CanonicalDeclaration.FileURI, Inc, FileName,
350  ToInclude.takeError());
351  }
352  // Prefer includes that do not need edits (i.e. already exist).
353  std::stable_partition(Completion.Includes.begin(),
354  Completion.Includes.end(),
355  [](const CodeCompletion::IncludeCandidate &I) {
356  return !I.Insertion.hasValue();
357  });
358  }
359 
360  void add(const CompletionCandidate &C, CodeCompletionString *SemaCCS) {
361  assert(bool(C.SemaResult) == bool(SemaCCS));
362  Bundled.emplace_back();
363  BundledEntry &S = Bundled.back();
364  if (C.SemaResult) {
365  bool IsPattern = C.SemaResult->Kind == CodeCompletionResult::RK_Pattern;
366  getSignature(*SemaCCS, &S.Signature, &S.SnippetSuffix,
367  &Completion.RequiredQualifier, IsPattern);
368  S.ReturnType = getReturnType(*SemaCCS);
369  } else if (C.IndexResult) {
370  S.Signature = C.IndexResult->Signature;
371  S.SnippetSuffix = C.IndexResult->CompletionSnippetSuffix;
372  S.ReturnType = C.IndexResult->ReturnType;
373  }
374  if (ExtractDocumentation && Completion.Documentation.empty()) {
375  if (C.IndexResult)
376  Completion.Documentation = C.IndexResult->Documentation;
377  else if (C.SemaResult)
378  Completion.Documentation = getDocComment(*ASTCtx, *C.SemaResult,
379  /*CommentsFromHeader=*/false);
380  }
381  }
382 
383  CodeCompletion build() {
384  Completion.ReturnType = summarizeReturnType();
385  Completion.Signature = summarizeSignature();
386  Completion.SnippetSuffix = summarizeSnippet();
387  Completion.BundleSize = Bundled.size();
388  return std::move(Completion);
389  }
390 
391 private:
392  struct BundledEntry {
393  std::string SnippetSuffix;
394  std::string Signature;
395  std::string ReturnType;
396  };
397 
398  // If all BundledEntries have the same value for a property, return it.
399  template <std::string BundledEntry::*Member>
400  const std::string *onlyValue() const {
401  auto B = Bundled.begin(), E = Bundled.end();
402  for (auto I = B + 1; I != E; ++I)
403  if (I->*Member != B->*Member)
404  return nullptr;
405  return &(B->*Member);
406  }
407 
408  template <bool BundledEntry::*Member> const bool *onlyValue() const {
409  auto B = Bundled.begin(), E = Bundled.end();
410  for (auto I = B + 1; I != E; ++I)
411  if (I->*Member != B->*Member)
412  return nullptr;
413  return &(B->*Member);
414  }
415 
416  std::string summarizeReturnType() const {
417  if (auto *RT = onlyValue<&BundledEntry::ReturnType>())
418  return *RT;
419  return "";
420  }
421 
422  std::string summarizeSnippet() const {
423  if (!GenerateSnippets)
424  return "";
425  auto *Snippet = onlyValue<&BundledEntry::SnippetSuffix>();
426  if (!Snippet)
427  // All bundles are function calls.
428  // FIXME(ibiryukov): sometimes add template arguments to a snippet, e.g.
429  // we need to complete 'forward<$1>($0)'.
430  return "($0)";
431  if (EnableFunctionArgSnippets)
432  return *Snippet;
433 
434  // Replace argument snippets with a simplified pattern.
435  if (Snippet->empty())
436  return "";
437  if (Completion.Kind == CompletionItemKind::Function ||
438  Completion.Kind == CompletionItemKind::Method) {
439  // Functions snippets can be of 2 types:
440  // - containing only function arguments, e.g.
441  // foo(${1:int p1}, ${2:int p2});
442  // We transform this pattern to '($0)' or '()'.
443  // - template arguments and function arguments, e.g.
444  // foo<${1:class}>(${2:int p1}).
445  // We transform this pattern to '<$1>()$0' or '<$0>()'.
446 
447  bool EmptyArgs = llvm::StringRef(*Snippet).endswith("()");
448  if (Snippet->front() == '<')
449  return EmptyArgs ? "<$1>()$0" : "<$1>($0)";
450  if (Snippet->front() == '(')
451  return EmptyArgs ? "()" : "($0)";
452  return *Snippet; // Not an arg snippet?
453  }
454  // 'CompletionItemKind::Interface' matches template type aliases.
455  if (Completion.Kind == CompletionItemKind::Interface ||
456  Completion.Kind == CompletionItemKind::Class) {
457  if (Snippet->front() != '<')
458  return *Snippet; // Not an arg snippet?
459 
460  // Classes and template using aliases can only have template arguments,
461  // e.g. Foo<${1:class}>.
462  if (llvm::StringRef(*Snippet).endswith("<>"))
463  return "<>"; // can happen with defaulted template arguments.
464  return "<$0>";
465  }
466  return *Snippet;
467  }
468 
469  std::string summarizeSignature() const {
470  if (auto *Signature = onlyValue<&BundledEntry::Signature>())
471  return *Signature;
472  // All bundles are function calls.
473  return "(…)";
474  }
475 
476  // ASTCtx can be nullptr if not run with sema.
477  ASTContext *ASTCtx;
478  CodeCompletion Completion;
479  llvm::SmallVector<BundledEntry, 1> Bundled;
480  bool ExtractDocumentation;
481  bool EnableFunctionArgSnippets;
482  /// When false, no snippets are generated argument lists.
483  bool GenerateSnippets;
484 };
485 
486 // Determine the symbol ID for a Sema code completion result, if possible.
487 llvm::Optional<SymbolID> getSymbolID(const CodeCompletionResult &R,
488  const SourceManager &SM) {
489  switch (R.Kind) {
490  case CodeCompletionResult::RK_Declaration:
491  case CodeCompletionResult::RK_Pattern: {
492  return clang::clangd::getSymbolID(R.Declaration);
493  }
494  case CodeCompletionResult::RK_Macro:
495  return clang::clangd::getSymbolID(R.Macro->getName(), R.MacroDefInfo, SM);
496  case CodeCompletionResult::RK_Keyword:
497  return None;
498  }
499  llvm_unreachable("unknown CodeCompletionResult kind");
500 }
501 
502 // Scopes of the partial identifier we're trying to complete.
503 // It is used when we query the index for more completion results.
504 struct SpecifiedScope {
505  // The scopes we should look in, determined by Sema.
506  //
507  // If the qualifier was fully resolved, we look for completions in these
508  // scopes; if there is an unresolved part of the qualifier, it should be
509  // resolved within these scopes.
510  //
511  // Examples of qualified completion:
512  //
513  // "::vec" => {""}
514  // "using namespace std; ::vec^" => {"", "std::"}
515  // "namespace ns {using namespace std;} ns::^" => {"ns::", "std::"}
516  // "std::vec^" => {""} // "std" unresolved
517  //
518  // Examples of unqualified completion:
519  //
520  // "vec^" => {""}
521  // "using namespace std; vec^" => {"", "std::"}
522  // "using namespace std; namespace ns { vec^ }" => {"ns::", "std::", ""}
523  //
524  // "" for global namespace, "ns::" for normal namespace.
525  std::vector<std::string> AccessibleScopes;
526  // The full scope qualifier as typed by the user (without the leading "::").
527  // Set if the qualifier is not fully resolved by Sema.
528  llvm::Optional<std::string> UnresolvedQualifier;
529 
530  // Construct scopes being queried in indexes. The results are deduplicated.
531  // This method format the scopes to match the index request representation.
532  std::vector<std::string> scopesForIndexQuery() {
533  std::set<std::string> Results;
534  for (llvm::StringRef AS : AccessibleScopes)
535  Results.insert(
536  (AS + (UnresolvedQualifier ? *UnresolvedQualifier : "")).str());
537  return {Results.begin(), Results.end()};
538  }
539 };
540 
541 // Get all scopes that will be queried in indexes and whether symbols from
542 // any scope is allowed. The first scope in the list is the preferred scope
543 // (e.g. enclosing namespace).
544 std::pair<std::vector<std::string>, bool>
545 getQueryScopes(CodeCompletionContext &CCContext, const Sema &CCSema,
546  const CompletionPrefix &HeuristicPrefix,
547  const CodeCompleteOptions &Opts) {
548  SpecifiedScope Scopes;
549  for (auto *Context : CCContext.getVisitedContexts()) {
550  if (isa<TranslationUnitDecl>(Context))
551  Scopes.AccessibleScopes.push_back(""); // global namespace
552  else if (isa<NamespaceDecl>(Context))
553  Scopes.AccessibleScopes.push_back(printNamespaceScope(*Context));
554  }
555 
556  const CXXScopeSpec *SemaSpecifier =
557  CCContext.getCXXScopeSpecifier().getValueOr(nullptr);
558  // Case 1: unqualified completion.
559  if (!SemaSpecifier) {
560  // Case 2 (exception): sema saw no qualifier, but there appears to be one!
561  // This can happen e.g. in incomplete macro expansions. Use heuristics.
562  if (!HeuristicPrefix.Qualifier.empty()) {
563  vlog("Sema said no scope specifier, but we saw {0} in the source code",
564  HeuristicPrefix.Qualifier);
565  StringRef SpelledSpecifier = HeuristicPrefix.Qualifier;
566  if (SpelledSpecifier.consume_front("::"))
567  Scopes.AccessibleScopes = {""};
568  Scopes.UnresolvedQualifier = SpelledSpecifier;
569  return {Scopes.scopesForIndexQuery(), false};
570  }
571  // The enclosing namespace must be first, it gets a quality boost.
572  std::vector<std::string> EnclosingAtFront;
573  std::string EnclosingScope = printNamespaceScope(*CCSema.CurContext);
574  EnclosingAtFront.push_back(EnclosingScope);
575  for (auto &S : Scopes.scopesForIndexQuery()) {
576  if (EnclosingScope != S)
577  EnclosingAtFront.push_back(std::move(S));
578  }
579  // Allow AllScopes completion as there is no explicit scope qualifier.
580  return {EnclosingAtFront, Opts.AllScopes};
581  }
582  // Case 3: sema saw and resolved a scope qualifier.
583  if (SemaSpecifier && SemaSpecifier->isValid())
584  return {Scopes.scopesForIndexQuery(), false};
585 
586  // Case 4: There was a qualifier, and Sema didn't resolve it.
587  Scopes.AccessibleScopes.push_back(""); // Make sure global scope is included.
588  llvm::StringRef SpelledSpecifier = Lexer::getSourceText(
589  CharSourceRange::getCharRange(SemaSpecifier->getRange()),
590  CCSema.SourceMgr, clang::LangOptions());
591  if (SpelledSpecifier.consume_front("::"))
592  Scopes.AccessibleScopes = {""};
593  Scopes.UnresolvedQualifier = SpelledSpecifier;
594  // Sema excludes the trailing "::".
595  if (!Scopes.UnresolvedQualifier->empty())
596  *Scopes.UnresolvedQualifier += "::";
597 
598  return {Scopes.scopesForIndexQuery(), false};
599 }
600 
601 // Should we perform index-based completion in a context of the specified kind?
602 // FIXME: consider allowing completion, but restricting the result types.
603 bool contextAllowsIndex(enum CodeCompletionContext::Kind K) {
604  switch (K) {
605  case CodeCompletionContext::CCC_TopLevel:
606  case CodeCompletionContext::CCC_ObjCInterface:
607  case CodeCompletionContext::CCC_ObjCImplementation:
608  case CodeCompletionContext::CCC_ObjCIvarList:
609  case CodeCompletionContext::CCC_ClassStructUnion:
610  case CodeCompletionContext::CCC_Statement:
611  case CodeCompletionContext::CCC_Expression:
612  case CodeCompletionContext::CCC_ObjCMessageReceiver:
613  case CodeCompletionContext::CCC_EnumTag:
614  case CodeCompletionContext::CCC_UnionTag:
615  case CodeCompletionContext::CCC_ClassOrStructTag:
616  case CodeCompletionContext::CCC_ObjCProtocolName:
617  case CodeCompletionContext::CCC_Namespace:
618  case CodeCompletionContext::CCC_Type:
619  case CodeCompletionContext::CCC_ParenthesizedExpression:
620  case CodeCompletionContext::CCC_ObjCInterfaceName:
621  case CodeCompletionContext::CCC_ObjCCategoryName:
622  case CodeCompletionContext::CCC_Symbol:
623  case CodeCompletionContext::CCC_SymbolOrNewName:
624  return true;
625  case CodeCompletionContext::CCC_OtherWithMacros:
626  case CodeCompletionContext::CCC_DotMemberAccess:
627  case CodeCompletionContext::CCC_ArrowMemberAccess:
628  case CodeCompletionContext::CCC_ObjCPropertyAccess:
629  case CodeCompletionContext::CCC_MacroName:
630  case CodeCompletionContext::CCC_MacroNameUse:
631  case CodeCompletionContext::CCC_PreprocessorExpression:
632  case CodeCompletionContext::CCC_PreprocessorDirective:
633  case CodeCompletionContext::CCC_SelectorName:
634  case CodeCompletionContext::CCC_TypeQualifiers:
635  case CodeCompletionContext::CCC_ObjCInstanceMessage:
636  case CodeCompletionContext::CCC_ObjCClassMessage:
637  case CodeCompletionContext::CCC_IncludedFile:
638  // FIXME: Provide identifier based completions for the following contexts:
639  case CodeCompletionContext::CCC_Other: // Be conservative.
640  case CodeCompletionContext::CCC_NaturalLanguage:
641  case CodeCompletionContext::CCC_Recovery:
642  case CodeCompletionContext::CCC_NewName:
643  return false;
644  }
645  llvm_unreachable("unknown code completion context");
646 }
647 
648 static bool isInjectedClass(const NamedDecl &D) {
649  if (auto *R = dyn_cast_or_null<RecordDecl>(&D))
650  if (R->isInjectedClassName())
651  return true;
652  return false;
653 }
654 
655 // Some member calls are blacklisted because they're so rarely useful.
656 static bool isBlacklistedMember(const NamedDecl &D) {
657  // Destructor completion is rarely useful, and works inconsistently.
658  // (s.^ completes ~string, but s.~st^ is an error).
659  if (D.getKind() == Decl::CXXDestructor)
660  return true;
661  // Injected name may be useful for A::foo(), but who writes A::A::foo()?
662  if (isInjectedClass(D))
663  return true;
664  // Explicit calls to operators are also rare.
665  auto NameKind = D.getDeclName().getNameKind();
666  if (NameKind == DeclarationName::CXXOperatorName ||
667  NameKind == DeclarationName::CXXLiteralOperatorName ||
668  NameKind == DeclarationName::CXXConversionFunctionName)
669  return true;
670  return false;
671 }
672 
673 // The CompletionRecorder captures Sema code-complete output, including context.
674 // It filters out ignored results (but doesn't apply fuzzy-filtering yet).
675 // It doesn't do scoring or conversion to CompletionItem yet, as we want to
676 // merge with index results first.
677 // Generally the fields and methods of this object should only be used from
678 // within the callback.
679 struct CompletionRecorder : public CodeCompleteConsumer {
680  CompletionRecorder(const CodeCompleteOptions &Opts,
681  llvm::unique_function<void()> ResultsCallback)
682  : CodeCompleteConsumer(Opts.getClangCompleteOpts()),
683  CCContext(CodeCompletionContext::CCC_Other), Opts(Opts),
684  CCAllocator(std::make_shared<GlobalCodeCompletionAllocator>()),
685  CCTUInfo(CCAllocator), ResultsCallback(std::move(ResultsCallback)) {
686  assert(this->ResultsCallback);
687  }
688 
689  std::vector<CodeCompletionResult> Results;
690  CodeCompletionContext CCContext;
691  Sema *CCSema = nullptr; // Sema that created the results.
692  // FIXME: Sema is scary. Can we store ASTContext and Preprocessor, instead?
693 
694  void ProcessCodeCompleteResults(class Sema &S, CodeCompletionContext Context,
695  CodeCompletionResult *InResults,
696  unsigned NumResults) override final {
697  // Results from recovery mode are generally useless, and the callback after
698  // recovery (if any) is usually more interesting. To make sure we handle the
699  // future callback from sema, we just ignore all callbacks in recovery mode,
700  // as taking only results from recovery mode results in poor completion
701  // results.
702  // FIXME: in case there is no future sema completion callback after the
703  // recovery mode, we might still want to provide some results (e.g. trivial
704  // identifier-based completion).
705  if (Context.getKind() == CodeCompletionContext::CCC_Recovery) {
706  log("Code complete: Ignoring sema code complete callback with Recovery "
707  "context.");
708  return;
709  }
710  // If a callback is called without any sema result and the context does not
711  // support index-based completion, we simply skip it to give way to
712  // potential future callbacks with results.
713  if (NumResults == 0 && !contextAllowsIndex(Context.getKind()))
714  return;
715  if (CCSema) {
716  log("Multiple code complete callbacks (parser backtracked?). "
717  "Dropping results from context {0}, keeping results from {1}.",
718  getCompletionKindString(Context.getKind()),
719  getCompletionKindString(this->CCContext.getKind()));
720  return;
721  }
722  // Record the completion context.
723  CCSema = &S;
724  CCContext = Context;
725 
726  // Retain the results we might want.
727  for (unsigned I = 0; I < NumResults; ++I) {
728  auto &Result = InResults[I];
729  // Class members that are shadowed by subclasses are usually noise.
730  if (Result.Hidden && Result.Declaration &&
731  Result.Declaration->isCXXClassMember())
732  continue;
733  if (!Opts.IncludeIneligibleResults &&
734  (Result.Availability == CXAvailability_NotAvailable ||
735  Result.Availability == CXAvailability_NotAccessible))
736  continue;
737  if (Result.Declaration &&
738  !Context.getBaseType().isNull() // is this a member-access context?
739  && isBlacklistedMember(*Result.Declaration))
740  continue;
741  // Skip injected class name when no class scope is not explicitly set.
742  // E.g. show injected A::A in `using A::A^` but not in "A^".
743  if (Result.Declaration && !Context.getCXXScopeSpecifier().hasValue() &&
744  isInjectedClass(*Result.Declaration))
745  continue;
746  // We choose to never append '::' to completion results in clangd.
747  Result.StartsNestedNameSpecifier = false;
748  Results.push_back(Result);
749  }
750  ResultsCallback();
751  }
752 
753  CodeCompletionAllocator &getAllocator() override { return *CCAllocator; }
754  CodeCompletionTUInfo &getCodeCompletionTUInfo() override { return CCTUInfo; }
755 
756  // Returns the filtering/sorting name for Result, which must be from Results.
757  // Returned string is owned by this recorder (or the AST).
758  llvm::StringRef getName(const CodeCompletionResult &Result) {
759  switch (Result.Kind) {
760  case CodeCompletionResult::RK_Declaration:
761  if (auto *ID = Result.Declaration->getIdentifier())
762  return ID->getName();
763  break;
764  case CodeCompletionResult::RK_Keyword:
765  return Result.Keyword;
766  case CodeCompletionResult::RK_Macro:
767  return Result.Macro->getName();
768  case CodeCompletionResult::RK_Pattern:
769  return Result.Pattern->getTypedText();
770  }
771  auto *CCS = codeCompletionString(Result);
772  return CCS->getTypedText();
773  }
774 
775  // Build a CodeCompletion string for R, which must be from Results.
776  // The CCS will be owned by this recorder.
777  CodeCompletionString *codeCompletionString(const CodeCompletionResult &R) {
778  // CodeCompletionResult doesn't seem to be const-correct. We own it, anyway.
779  return const_cast<CodeCompletionResult &>(R).CreateCodeCompletionString(
780  *CCSema, CCContext, *CCAllocator, CCTUInfo,
781  /*IncludeBriefComments=*/false);
782  }
783 
784 private:
785  CodeCompleteOptions Opts;
786  std::shared_ptr<GlobalCodeCompletionAllocator> CCAllocator;
787  CodeCompletionTUInfo CCTUInfo;
788  llvm::unique_function<void()> ResultsCallback;
789 };
790 
791 struct ScoredSignature {
792  // When set, requires documentation to be requested from the index with this
793  // ID.
794  llvm::Optional<SymbolID> IDForDoc;
795  SignatureInformation Signature;
796  SignatureQualitySignals Quality;
797 };
798 
799 class SignatureHelpCollector final : public CodeCompleteConsumer {
800 public:
801  SignatureHelpCollector(const clang::CodeCompleteOptions &CodeCompleteOpts,
802  const SymbolIndex *Index, SignatureHelp &SigHelp)
803  : CodeCompleteConsumer(CodeCompleteOpts), SigHelp(SigHelp),
804  Allocator(std::make_shared<clang::GlobalCodeCompletionAllocator>()),
805  CCTUInfo(Allocator), Index(Index) {}
806 
807  void ProcessOverloadCandidates(Sema &S, unsigned CurrentArg,
808  OverloadCandidate *Candidates,
809  unsigned NumCandidates,
810  SourceLocation OpenParLoc) override {
811  assert(!OpenParLoc.isInvalid());
812  SourceManager &SrcMgr = S.getSourceManager();
813  OpenParLoc = SrcMgr.getFileLoc(OpenParLoc);
814  if (SrcMgr.isInMainFile(OpenParLoc))
815  SigHelp.argListStart = sourceLocToPosition(SrcMgr, OpenParLoc);
816  else
817  elog("Location oustide main file in signature help: {0}",
818  OpenParLoc.printToString(SrcMgr));
819 
820  std::vector<ScoredSignature> ScoredSignatures;
821  SigHelp.signatures.reserve(NumCandidates);
822  ScoredSignatures.reserve(NumCandidates);
823  // FIXME(rwols): How can we determine the "active overload candidate"?
824  // Right now the overloaded candidates seem to be provided in a "best fit"
825  // order, so I'm not too worried about this.
826  SigHelp.activeSignature = 0;
827  assert(CurrentArg <= (unsigned)std::numeric_limits<int>::max() &&
828  "too many arguments");
829  SigHelp.activeParameter = static_cast<int>(CurrentArg);
830  for (unsigned I = 0; I < NumCandidates; ++I) {
831  OverloadCandidate Candidate = Candidates[I];
832  // We want to avoid showing instantiated signatures, because they may be
833  // long in some cases (e.g. when 'T' is substituted with 'std::string', we
834  // would get 'std::basic_string<char>').
835  if (auto *Func = Candidate.getFunction()) {
836  if (auto *Pattern = Func->getTemplateInstantiationPattern())
837  Candidate = OverloadCandidate(Pattern);
838  }
839 
840  const auto *CCS = Candidate.CreateSignatureString(
841  CurrentArg, S, *Allocator, CCTUInfo, true);
842  assert(CCS && "Expected the CodeCompletionString to be non-null");
843  ScoredSignatures.push_back(processOverloadCandidate(
844  Candidate, *CCS,
845  Candidate.getFunction()
846  ? getDeclComment(S.getASTContext(), *Candidate.getFunction())
847  : ""));
848  }
849 
850  // Sema does not load the docs from the preamble, so we need to fetch extra
851  // docs from the index instead.
852  llvm::DenseMap<SymbolID, std::string> FetchedDocs;
853  if (Index) {
854  LookupRequest IndexRequest;
855  for (const auto &S : ScoredSignatures) {
856  if (!S.IDForDoc)
857  continue;
858  IndexRequest.IDs.insert(*S.IDForDoc);
859  }
860  Index->lookup(IndexRequest, [&](const Symbol &S) {
861  if (!S.Documentation.empty())
862  FetchedDocs[S.ID] = S.Documentation;
863  });
864  log("SigHelp: requested docs for {0} symbols from the index, got {1} "
865  "symbols with non-empty docs in the response",
866  IndexRequest.IDs.size(), FetchedDocs.size());
867  }
868 
869  llvm::sort(ScoredSignatures, [](const ScoredSignature &L,
870  const ScoredSignature &R) {
871  // Ordering follows:
872  // - Less number of parameters is better.
873  // - Function is better than FunctionType which is better than
874  // Function Template.
875  // - High score is better.
876  // - Shorter signature is better.
877  // - Alphabetically smaller is better.
878  if (L.Quality.NumberOfParameters != R.Quality.NumberOfParameters)
879  return L.Quality.NumberOfParameters < R.Quality.NumberOfParameters;
880  if (L.Quality.NumberOfOptionalParameters !=
881  R.Quality.NumberOfOptionalParameters)
882  return L.Quality.NumberOfOptionalParameters <
883  R.Quality.NumberOfOptionalParameters;
884  if (L.Quality.Kind != R.Quality.Kind) {
885  using OC = CodeCompleteConsumer::OverloadCandidate;
886  switch (L.Quality.Kind) {
887  case OC::CK_Function:
888  return true;
889  case OC::CK_FunctionType:
890  return R.Quality.Kind != OC::CK_Function;
891  case OC::CK_FunctionTemplate:
892  return false;
893  }
894  llvm_unreachable("Unknown overload candidate type.");
895  }
896  if (L.Signature.label.size() != R.Signature.label.size())
897  return L.Signature.label.size() < R.Signature.label.size();
898  return L.Signature.label < R.Signature.label;
899  });
900 
901  for (auto &SS : ScoredSignatures) {
902  auto IndexDocIt =
903  SS.IDForDoc ? FetchedDocs.find(*SS.IDForDoc) : FetchedDocs.end();
904  if (IndexDocIt != FetchedDocs.end())
905  SS.Signature.documentation = IndexDocIt->second;
906 
907  SigHelp.signatures.push_back(std::move(SS.Signature));
908  }
909  }
910 
911  GlobalCodeCompletionAllocator &getAllocator() override { return *Allocator; }
912 
913  CodeCompletionTUInfo &getCodeCompletionTUInfo() override { return CCTUInfo; }
914 
915 private:
916  void processParameterChunk(llvm::StringRef ChunkText,
917  SignatureInformation &Signature) const {
918  // (!) this is O(n), should still be fast compared to building ASTs.
919  unsigned ParamStartOffset = lspLength(Signature.label);
920  unsigned ParamEndOffset = ParamStartOffset + lspLength(ChunkText);
921  // A piece of text that describes the parameter that corresponds to
922  // the code-completion location within a function call, message send,
923  // macro invocation, etc.
924  Signature.label += ChunkText;
925  ParameterInformation Info;
926  Info.labelOffsets.emplace(ParamStartOffset, ParamEndOffset);
927  // FIXME: only set 'labelOffsets' when all clients migrate out of it.
928  Info.labelString = ChunkText;
929 
930  Signature.parameters.push_back(std::move(Info));
931  }
932 
933  void processOptionalChunk(const CodeCompletionString &CCS,
934  SignatureInformation &Signature,
935  SignatureQualitySignals &Signal) const {
936  for (const auto &Chunk : CCS) {
937  switch (Chunk.Kind) {
938  case CodeCompletionString::CK_Optional:
939  assert(Chunk.Optional &&
940  "Expected the optional code completion string to be non-null.");
941  processOptionalChunk(*Chunk.Optional, Signature, Signal);
942  break;
943  case CodeCompletionString::CK_VerticalSpace:
944  break;
945  case CodeCompletionString::CK_CurrentParameter:
946  case CodeCompletionString::CK_Placeholder:
947  processParameterChunk(Chunk.Text, Signature);
948  Signal.NumberOfOptionalParameters++;
949  break;
950  default:
951  Signature.label += Chunk.Text;
952  break;
953  }
954  }
955  }
956 
957  // FIXME(ioeric): consider moving CodeCompletionString logic here to
958  // CompletionString.h.
959  ScoredSignature processOverloadCandidate(const OverloadCandidate &Candidate,
960  const CodeCompletionString &CCS,
961  llvm::StringRef DocComment) const {
962  SignatureInformation Signature;
963  SignatureQualitySignals Signal;
964  const char *ReturnType = nullptr;
965 
966  Signature.documentation = formatDocumentation(CCS, DocComment);
967  Signal.Kind = Candidate.getKind();
968 
969  for (const auto &Chunk : CCS) {
970  switch (Chunk.Kind) {
971  case CodeCompletionString::CK_ResultType:
972  // A piece of text that describes the type of an entity or,
973  // for functions and methods, the return type.
974  assert(!ReturnType && "Unexpected CK_ResultType");
975  ReturnType = Chunk.Text;
976  break;
977  case CodeCompletionString::CK_CurrentParameter:
978  case CodeCompletionString::CK_Placeholder:
979  processParameterChunk(Chunk.Text, Signature);
980  Signal.NumberOfParameters++;
981  break;
982  case CodeCompletionString::CK_Optional: {
983  // The rest of the parameters are defaulted/optional.
984  assert(Chunk.Optional &&
985  "Expected the optional code completion string to be non-null.");
986  processOptionalChunk(*Chunk.Optional, Signature, Signal);
987  break;
988  }
989  case CodeCompletionString::CK_VerticalSpace:
990  break;
991  default:
992  Signature.label += Chunk.Text;
993  break;
994  }
995  }
996  if (ReturnType) {
997  Signature.label += " -> ";
998  Signature.label += ReturnType;
999  }
1000  dlog("Signal for {0}: {1}", Signature, Signal);
1001  ScoredSignature Result;
1002  Result.Signature = std::move(Signature);
1003  Result.Quality = Signal;
1004  Result.IDForDoc =
1005  Result.Signature.documentation.empty() && Candidate.getFunction()
1006  ? clangd::getSymbolID(Candidate.getFunction())
1007  : None;
1008  return Result;
1009  }
1010 
1011  SignatureHelp &SigHelp;
1012  std::shared_ptr<clang::GlobalCodeCompletionAllocator> Allocator;
1013  CodeCompletionTUInfo CCTUInfo;
1014  const SymbolIndex *Index;
1015 }; // SignatureHelpCollector
1016 
1017 struct SemaCompleteInput {
1019  const tooling::CompileCommand &Command;
1020  const PreambleData *Preamble;
1021  llvm::StringRef Contents;
1022  size_t Offset;
1023  llvm::IntrusiveRefCntPtr<llvm::vfs::FileSystem> VFS;
1024 };
1025 
1026 void loadMainFilePreambleMacros(const Preprocessor &PP,
1027  const PreambleData &Preamble) {
1028  // The ExternalPreprocessorSource has our macros, if we know where to look.
1029  // We can read all the macros using PreambleMacros->ReadDefinedMacros(),
1030  // but this includes transitively included files, so may deserialize a lot.
1031  ExternalPreprocessorSource *PreambleMacros = PP.getExternalSource();
1032  // As we have the names of the macros, we can look up their IdentifierInfo
1033  // and then use this to load just the macros we want.
1034  IdentifierInfoLookup *PreambleIdentifiers =
1035  PP.getIdentifierTable().getExternalIdentifierLookup();
1036  if (!PreambleIdentifiers || !PreambleMacros)
1037  return;
1038  for (const auto &MacroName : Preamble.Macros.Names)
1039  if (auto *II = PreambleIdentifiers->get(MacroName.getKey()))
1040  if (II->isOutOfDate())
1041  PreambleMacros->updateOutOfDateIdentifier(*II);
1042 }
1043 
1044 // Invokes Sema code completion on a file.
1045 // If \p Includes is set, it will be updated based on the compiler invocation.
1046 bool semaCodeComplete(std::unique_ptr<CodeCompleteConsumer> Consumer,
1047  const clang::CodeCompleteOptions &Options,
1048  const SemaCompleteInput &Input,
1049  IncludeStructure *Includes = nullptr) {
1050  trace::Span Tracer("Sema completion");
1051  llvm::IntrusiveRefCntPtr<llvm::vfs::FileSystem> VFS = Input.VFS;
1052  if (Input.Preamble && Input.Preamble->StatCache)
1053  VFS = Input.Preamble->StatCache->getConsumingFS(std::move(VFS));
1054  ParseInputs ParseInput;
1055  ParseInput.CompileCommand = Input.Command;
1056  ParseInput.FS = VFS;
1057  ParseInput.Contents = Input.Contents;
1058  ParseInput.Opts = ParseOptions();
1059 
1060  IgnoreDiagnostics IgnoreDiags;
1061  auto CI = buildCompilerInvocation(ParseInput, IgnoreDiags);
1062  if (!CI) {
1063  elog("Couldn't create CompilerInvocation");
1064  return false;
1065  }
1066  auto &FrontendOpts = CI->getFrontendOpts();
1067  FrontendOpts.SkipFunctionBodies = true;
1068  // Disable typo correction in Sema.
1069  CI->getLangOpts()->SpellChecking = false;
1070  // Setup code completion.
1071  FrontendOpts.CodeCompleteOpts = Options;
1072  FrontendOpts.CodeCompletionAt.FileName = Input.FileName;
1073  std::tie(FrontendOpts.CodeCompletionAt.Line,
1074  FrontendOpts.CodeCompletionAt.Column) =
1075  offsetToClangLineColumn(Input.Contents, Input.Offset);
1076 
1077  std::unique_ptr<llvm::MemoryBuffer> ContentsBuffer =
1078  llvm::MemoryBuffer::getMemBufferCopy(Input.Contents, Input.FileName);
1079  // The diagnostic options must be set before creating a CompilerInstance.
1080  CI->getDiagnosticOpts().IgnoreWarnings = true;
1081  // We reuse the preamble whether it's valid or not. This is a
1082  // correctness/performance tradeoff: building without a preamble is slow, and
1083  // completion is latency-sensitive.
1084  // However, if we're completing *inside* the preamble section of the draft,
1085  // overriding the preamble will break sema completion. Fortunately we can just
1086  // skip all includes in this case; these completions are really simple.
1087  PreambleBounds PreambleRegion =
1088  ComputePreambleBounds(*CI->getLangOpts(), ContentsBuffer.get(), 0);
1089  bool CompletingInPreamble = PreambleRegion.Size > Input.Offset;
1090  // NOTE: we must call BeginSourceFile after prepareCompilerInstance. Otherwise
1091  // the remapped buffers do not get freed.
1092  auto Clang = prepareCompilerInstance(
1093  std::move(CI),
1094  (Input.Preamble && !CompletingInPreamble) ? &Input.Preamble->Preamble
1095  : nullptr,
1096  std::move(ContentsBuffer), std::move(VFS), IgnoreDiags);
1097  Clang->getPreprocessorOpts().SingleFileParseMode = CompletingInPreamble;
1098  Clang->setCodeCompletionConsumer(Consumer.release());
1099 
1101  if (!Action.BeginSourceFile(*Clang, Clang->getFrontendOpts().Inputs[0])) {
1102  log("BeginSourceFile() failed when running codeComplete for {0}",
1103  Input.FileName);
1104  return false;
1105  }
1106  // Macros can be defined within the preamble region of the main file.
1107  // They don't fall nicely into our index/Sema dichotomy:
1108  // - they're not indexed for completion (they're not available across files)
1109  // - but Sema code complete won't see them: as part of the preamble, they're
1110  // deserialized only when mentioned.
1111  // Force them to be deserialized so SemaCodeComplete sees them.
1112  if (Input.Preamble)
1113  loadMainFilePreambleMacros(Clang->getPreprocessor(), *Input.Preamble);
1114  if (Includes)
1115  Clang->getPreprocessor().addPPCallbacks(
1116  collectIncludeStructureCallback(Clang->getSourceManager(), Includes));
1117  if (llvm::Error Err = Action.Execute()) {
1118  log("Execute() failed when running codeComplete for {0}: {1}",
1119  Input.FileName, toString(std::move(Err)));
1120  return false;
1121  }
1122  Action.EndSourceFile();
1123 
1124  return true;
1125 }
1126 
1127 // Should we allow index completions in the specified context?
1128 bool allowIndex(CodeCompletionContext &CC) {
1129  if (!contextAllowsIndex(CC.getKind()))
1130  return false;
1131  // We also avoid ClassName::bar (but allow namespace::bar).
1132  auto Scope = CC.getCXXScopeSpecifier();
1133  if (!Scope)
1134  return true;
1135  NestedNameSpecifier *NameSpec = (*Scope)->getScopeRep();
1136  if (!NameSpec)
1137  return true;
1138  // We only query the index when qualifier is a namespace.
1139  // If it's a class, we rely solely on sema completions.
1140  switch (NameSpec->getKind()) {
1141  case NestedNameSpecifier::Global:
1143  case NestedNameSpecifier::NamespaceAlias:
1144  return true;
1145  case NestedNameSpecifier::Super:
1146  case NestedNameSpecifier::TypeSpec:
1147  case NestedNameSpecifier::TypeSpecWithTemplate:
1148  // Unresolved inside a template.
1150  return false;
1151  }
1152  llvm_unreachable("invalid NestedNameSpecifier kind");
1153 }
1154 
1155 std::future<SymbolSlab> startAsyncFuzzyFind(const SymbolIndex &Index,
1156  const FuzzyFindRequest &Req) {
1157  return runAsync<SymbolSlab>([&Index, Req]() {
1158  trace::Span Tracer("Async fuzzyFind");
1159  SymbolSlab::Builder Syms;
1160  Index.fuzzyFind(Req, [&Syms](const Symbol &Sym) { Syms.insert(Sym); });
1161  return std::move(Syms).build();
1162  });
1163 }
1164 
1165 // Creates a `FuzzyFindRequest` based on the cached index request from the
1166 // last completion, if any, and the speculated completion filter text in the
1167 // source code.
1168 FuzzyFindRequest speculativeFuzzyFindRequestForCompletion(
1169  FuzzyFindRequest CachedReq, const CompletionPrefix &HeuristicPrefix) {
1170  CachedReq.Query = HeuristicPrefix.Name;
1171  return CachedReq;
1172 }
1173 
1174 // Runs Sema-based (AST) and Index-based completion, returns merged results.
1175 //
1176 // There are a few tricky considerations:
1177 // - the AST provides information needed for the index query (e.g. which
1178 // namespaces to search in). So Sema must start first.
1179 // - we only want to return the top results (Opts.Limit).
1180 // Building CompletionItems for everything else is wasteful, so we want to
1181 // preserve the "native" format until we're done with scoring.
1182 // - the data underlying Sema completion items is owned by the AST and various
1183 // other arenas, which must stay alive for us to build CompletionItems.
1184 // - we may get duplicate results from Sema and the Index, we need to merge.
1185 //
1186 // So we start Sema completion first, and do all our work in its callback.
1187 // We use the Sema context information to query the index.
1188 // Then we merge the two result sets, producing items that are Sema/Index/Both.
1189 // These items are scored, and the top N are synthesized into the LSP response.
1190 // Finally, we can clean up the data structures created by Sema completion.
1191 //
1192 // Main collaborators are:
1193 // - semaCodeComplete sets up the compiler machinery to run code completion.
1194 // - CompletionRecorder captures Sema completion results, including context.
1195 // - SymbolIndex (Opts.Index) provides index completion results as Symbols
1196 // - CompletionCandidates are the result of merging Sema and Index results.
1197 // Each candidate points to an underlying CodeCompletionResult (Sema), a
1198 // Symbol (Index), or both. It computes the result quality score.
1199 // CompletionCandidate also does conversion to CompletionItem (at the end).
1200 // - FuzzyMatcher scores how the candidate matches the partial identifier.
1201 // This score is combined with the result quality score for the final score.
1202 // - TopN determines the results with the best score.
1203 class CodeCompleteFlow {
1204  PathRef FileName;
1205  IncludeStructure Includes; // Complete once the compiler runs.
1206  SpeculativeFuzzyFind *SpecFuzzyFind; // Can be nullptr.
1207  const CodeCompleteOptions &Opts;
1208 
1209  // Sema takes ownership of Recorder. Recorder is valid until Sema cleanup.
1210  CompletionRecorder *Recorder = nullptr;
1211  CodeCompletionContext::Kind CCContextKind = CodeCompletionContext::CCC_Other;
1212  bool IsUsingDeclaration = false;
1213  // Counters for logging.
1214  int NSema = 0, NIndex = 0, NSemaAndIndex = 0, NIdent = 0;
1215  bool Incomplete = false; // Would more be available with a higher limit?
1216  CompletionPrefix HeuristicPrefix;
1217  llvm::Optional<FuzzyMatcher> Filter; // Initialized once Sema runs.
1218  Range ReplacedRange;
1219  std::vector<std::string> QueryScopes; // Initialized once Sema runs.
1220  // Initialized once QueryScopes is initialized, if there are scopes.
1221  llvm::Optional<ScopeDistance> ScopeProximity;
1222  llvm::Optional<OpaqueType> PreferredType; // Initialized once Sema runs.
1223  // Whether to query symbols from any scope. Initialized once Sema runs.
1224  bool AllScopes = false;
1225  llvm::StringSet<> ContextWords;
1226  // Include-insertion and proximity scoring rely on the include structure.
1227  // This is available after Sema has run.
1228  llvm::Optional<IncludeInserter> Inserter; // Available during runWithSema.
1229  llvm::Optional<URIDistance> FileProximity; // Initialized once Sema runs.
1230  /// Speculative request based on the cached request and the filter text before
1231  /// the cursor.
1232  /// Initialized right before sema run. This is only set if `SpecFuzzyFind` is
1233  /// set and contains a cached request.
1234  llvm::Optional<FuzzyFindRequest> SpecReq;
1235 
1236 public:
1237  // A CodeCompleteFlow object is only useful for calling run() exactly once.
1238  CodeCompleteFlow(PathRef FileName, const IncludeStructure &Includes,
1239  SpeculativeFuzzyFind *SpecFuzzyFind,
1240  const CodeCompleteOptions &Opts)
1241  : FileName(FileName), Includes(Includes), SpecFuzzyFind(SpecFuzzyFind),
1242  Opts(Opts) {}
1243 
1244  CodeCompleteResult run(const SemaCompleteInput &SemaCCInput) && {
1245  trace::Span Tracer("CodeCompleteFlow");
1246  HeuristicPrefix =
1247  guessCompletionPrefix(SemaCCInput.Contents, SemaCCInput.Offset);
1248  populateContextWords(SemaCCInput.Contents);
1249  if (Opts.Index && SpecFuzzyFind && SpecFuzzyFind->CachedReq.hasValue()) {
1250  assert(!SpecFuzzyFind->Result.valid());
1251  SpecReq = speculativeFuzzyFindRequestForCompletion(
1252  *SpecFuzzyFind->CachedReq, HeuristicPrefix);
1253  SpecFuzzyFind->Result = startAsyncFuzzyFind(*Opts.Index, *SpecReq);
1254  }
1255 
1256  // We run Sema code completion first. It builds an AST and calculates:
1257  // - completion results based on the AST.
1258  // - partial identifier and context. We need these for the index query.
1259  CodeCompleteResult Output;
1260  auto RecorderOwner = std::make_unique<CompletionRecorder>(Opts, [&]() {
1261  assert(Recorder && "Recorder is not set");
1262  CCContextKind = Recorder->CCContext.getKind();
1263  IsUsingDeclaration = Recorder->CCContext.isUsingDeclaration();
1264  auto Style = getFormatStyleForFile(
1265  SemaCCInput.FileName, SemaCCInput.Contents, SemaCCInput.VFS.get());
1266  // If preprocessor was run, inclusions from preprocessor callback should
1267  // already be added to Includes.
1268  Inserter.emplace(
1269  SemaCCInput.FileName, SemaCCInput.Contents, Style,
1270  SemaCCInput.Command.Directory,
1271  &Recorder->CCSema->getPreprocessor().getHeaderSearchInfo());
1272  for (const auto &Inc : Includes.MainFileIncludes)
1273  Inserter->addExisting(Inc);
1274 
1275  // Most of the cost of file proximity is in initializing the FileDistance
1276  // structures based on the observed includes, once per query. Conceptually
1277  // that happens here (though the per-URI-scheme initialization is lazy).
1278  // The per-result proximity scoring is (amortized) very cheap.
1279  FileDistanceOptions ProxOpts{}; // Use defaults.
1280  const auto &SM = Recorder->CCSema->getSourceManager();
1281  llvm::StringMap<SourceParams> ProxSources;
1282  for (auto &Entry : Includes.includeDepth(
1283  SM.getFileEntryForID(SM.getMainFileID())->getName())) {
1284  auto &Source = ProxSources[Entry.getKey()];
1285  Source.Cost = Entry.getValue() * ProxOpts.IncludeCost;
1286  // Symbols near our transitive includes are good, but only consider
1287  // things in the same directory or below it. Otherwise there can be
1288  // many false positives.
1289  if (Entry.getValue() > 0)
1290  Source.MaxUpTraversals = 1;
1291  }
1292  FileProximity.emplace(ProxSources, ProxOpts);
1293 
1294  Output = runWithSema();
1295  Inserter.reset(); // Make sure this doesn't out-live Clang.
1296  SPAN_ATTACH(Tracer, "sema_completion_kind",
1297  getCompletionKindString(CCContextKind));
1298  log("Code complete: sema context {0}, query scopes [{1}] (AnyScope={2}), "
1299  "expected type {3}{4}",
1300  getCompletionKindString(CCContextKind),
1301  llvm::join(QueryScopes.begin(), QueryScopes.end(), ","), AllScopes,
1302  PreferredType ? Recorder->CCContext.getPreferredType().getAsString()
1303  : "<none>",
1304  IsUsingDeclaration ? ", inside using declaration" : "");
1305  });
1306 
1307  Recorder = RecorderOwner.get();
1308 
1309  semaCodeComplete(std::move(RecorderOwner), Opts.getClangCompleteOpts(),
1310  SemaCCInput, &Includes);
1311  logResults(Output, Tracer);
1312  return Output;
1313  }
1314 
1315  void logResults(const CodeCompleteResult &Output, const trace::Span &Tracer) {
1316  SPAN_ATTACH(Tracer, "sema_results", NSema);
1317  SPAN_ATTACH(Tracer, "index_results", NIndex);
1318  SPAN_ATTACH(Tracer, "merged_results", NSemaAndIndex);
1319  SPAN_ATTACH(Tracer, "identifier_results", NIdent);
1320  SPAN_ATTACH(Tracer, "returned_results", int64_t(Output.Completions.size()));
1321  SPAN_ATTACH(Tracer, "incomplete", Output.HasMore);
1322  log("Code complete: {0} results from Sema, {1} from Index, "
1323  "{2} matched, {3} from identifiers, {4} returned{5}.",
1324  NSema, NIndex, NSemaAndIndex, NIdent, Output.Completions.size(),
1325  Output.HasMore ? " (incomplete)" : "");
1326  assert(!Opts.Limit || Output.Completions.size() <= Opts.Limit);
1327  // We don't assert that isIncomplete means we hit a limit.
1328  // Indexes may choose to impose their own limits even if we don't have one.
1329  }
1330 
1331  CodeCompleteResult
1332  runWithoutSema(llvm::StringRef Content, size_t Offset,
1333  llvm::IntrusiveRefCntPtr<llvm::vfs::FileSystem> VFS) && {
1334  trace::Span Tracer("CodeCompleteWithoutSema");
1335  // Fill in fields normally set by runWithSema()
1336  HeuristicPrefix = guessCompletionPrefix(Content, Offset);
1337  populateContextWords(Content);
1338  CCContextKind = CodeCompletionContext::CCC_Recovery;
1339  IsUsingDeclaration = false;
1340  Filter = FuzzyMatcher(HeuristicPrefix.Name);
1341  auto Pos = offsetToPosition(Content, Offset);
1342  ReplacedRange.start = ReplacedRange.end = Pos;
1343  ReplacedRange.start.character -= HeuristicPrefix.Name.size();
1344 
1345  llvm::StringMap<SourceParams> ProxSources;
1346  ProxSources[FileName].Cost = 0;
1347  FileProximity.emplace(ProxSources);
1348 
1349  auto Style = getFormatStyleForFile(FileName, Content, VFS.get());
1350  // This will only insert verbatim headers.
1351  Inserter.emplace(FileName, Content, Style,
1352  /*BuildDir=*/"", /*HeaderSearchInfo=*/nullptr);
1353 
1354  auto Identifiers = collectIdentifiers(Content, Style);
1355  std::vector<RawIdentifier> IdentifierResults;
1356  for (const auto &IDAndCount : Identifiers) {
1357  RawIdentifier ID;
1358  ID.Name = IDAndCount.first();
1359  ID.References = IDAndCount.second;
1360  // Avoid treating typed filter as an identifier.
1361  if (ID.Name == HeuristicPrefix.Name)
1362  --ID.References;
1363  if (ID.References > 0)
1364  IdentifierResults.push_back(std::move(ID));
1365  }
1366 
1367  // Simplified version of getQueryScopes():
1368  // - accessible scopes are determined heuristically.
1369  // - all-scopes query if no qualifier was typed (and it's allowed).
1370  SpecifiedScope Scopes;
1371  Scopes.AccessibleScopes =
1372  visibleNamespaces(Content.take_front(Offset), Style);
1373  for (std::string &S : Scopes.AccessibleScopes)
1374  if (!S.empty())
1375  S.append("::"); // visibleNamespaces doesn't include trailing ::.
1376  if (HeuristicPrefix.Qualifier.empty())
1377  AllScopes = Opts.AllScopes;
1378  else if (HeuristicPrefix.Qualifier.startswith("::")) {
1379  Scopes.AccessibleScopes = {""};
1380  Scopes.UnresolvedQualifier = HeuristicPrefix.Qualifier.drop_front(2);
1381  } else
1382  Scopes.UnresolvedQualifier = HeuristicPrefix.Qualifier;
1383  // First scope is the (modified) enclosing scope.
1384  QueryScopes = Scopes.scopesForIndexQuery();
1385  ScopeProximity.emplace(QueryScopes);
1386 
1387  SymbolSlab IndexResults = Opts.Index ? queryIndex() : SymbolSlab();
1388 
1389  CodeCompleteResult Output = toCodeCompleteResult(mergeResults(
1390  /*SemaResults=*/{}, IndexResults, IdentifierResults));
1391  Output.RanParser = false;
1392  logResults(Output, Tracer);
1393  return Output;
1394  }
1395 
1396 private:
1397  void populateContextWords(llvm::StringRef Content) {
1398  // Take last 3 lines before the completion point.
1399  unsigned RangeEnd = HeuristicPrefix.Qualifier.begin() - Content.data(),
1400  RangeBegin = RangeEnd;
1401  for (size_t I = 0; I < 3 && RangeBegin > 0; ++I) {
1402  auto PrevNL = Content.rfind('\n', RangeBegin);
1403  if (PrevNL == StringRef::npos) {
1404  RangeBegin = 0;
1405  break;
1406  }
1407  RangeBegin = PrevNL;
1408  }
1409 
1410  ContextWords = collectWords(Content.slice(RangeBegin, RangeEnd));
1411  dlog("Completion context words: {0}",
1412  llvm::join(ContextWords.keys(), ", "));
1413  }
1414 
1415  // This is called by run() once Sema code completion is done, but before the
1416  // Sema data structures are torn down. It does all the real work.
1417  CodeCompleteResult runWithSema() {
1418  const auto &CodeCompletionRange = CharSourceRange::getCharRange(
1419  Recorder->CCSema->getPreprocessor().getCodeCompletionTokenRange());
1420  // When we are getting completions with an empty identifier, for example
1421  // std::vector<int> asdf;
1422  // asdf.^;
1423  // Then the range will be invalid and we will be doing insertion, use
1424  // current cursor position in such cases as range.
1425  if (CodeCompletionRange.isValid()) {
1426  ReplacedRange = halfOpenToRange(Recorder->CCSema->getSourceManager(),
1427  CodeCompletionRange);
1428  } else {
1429  const auto &Pos = sourceLocToPosition(
1430  Recorder->CCSema->getSourceManager(),
1431  Recorder->CCSema->getPreprocessor().getCodeCompletionLoc());
1432  ReplacedRange.start = ReplacedRange.end = Pos;
1433  }
1434  Filter = FuzzyMatcher(
1435  Recorder->CCSema->getPreprocessor().getCodeCompletionFilter());
1436  std::tie(QueryScopes, AllScopes) = getQueryScopes(
1437  Recorder->CCContext, *Recorder->CCSema, HeuristicPrefix, Opts);
1438  if (!QueryScopes.empty())
1439  ScopeProximity.emplace(QueryScopes);
1440  PreferredType =
1441  OpaqueType::fromType(Recorder->CCSema->getASTContext(),
1442  Recorder->CCContext.getPreferredType());
1443  // Sema provides the needed context to query the index.
1444  // FIXME: in addition to querying for extra/overlapping symbols, we should
1445  // explicitly request symbols corresponding to Sema results.
1446  // We can use their signals even if the index can't suggest them.
1447  // We must copy index results to preserve them, but there are at most Limit.
1448  auto IndexResults = (Opts.Index && allowIndex(Recorder->CCContext))
1449  ? queryIndex()
1450  : SymbolSlab();
1451  trace::Span Tracer("Populate CodeCompleteResult");
1452  // Merge Sema and Index results, score them, and pick the winners.
1453  auto Top =
1454  mergeResults(Recorder->Results, IndexResults, /*Identifiers*/ {});
1455  return toCodeCompleteResult(Top);
1456  }
1457 
1458  CodeCompleteResult
1459  toCodeCompleteResult(const std::vector<ScoredBundle> &Scored) {
1460  CodeCompleteResult Output;
1461 
1462  // Convert the results to final form, assembling the expensive strings.
1463  for (auto &C : Scored) {
1464  Output.Completions.push_back(toCodeCompletion(C.first));
1465  Output.Completions.back().Score = C.second;
1466  Output.Completions.back().CompletionTokenRange = ReplacedRange;
1467  }
1468  Output.HasMore = Incomplete;
1469  Output.Context = CCContextKind;
1470  return Output;
1471  }
1472 
1473  SymbolSlab queryIndex() {
1474  trace::Span Tracer("Query index");
1475  SPAN_ATTACH(Tracer, "limit", int64_t(Opts.Limit));
1476 
1477  // Build the query.
1478  FuzzyFindRequest Req;
1479  if (Opts.Limit)
1480  Req.Limit = Opts.Limit;
1481  Req.Query = Filter->pattern();
1482  Req.RestrictForCodeCompletion = true;
1483  Req.Scopes = QueryScopes;
1484  Req.AnyScope = AllScopes;
1485  // FIXME: we should send multiple weighted paths here.
1486  Req.ProximityPaths.push_back(FileName);
1487  if (PreferredType)
1488  Req.PreferredTypes.push_back(PreferredType->raw());
1489  vlog("Code complete: fuzzyFind({0:2})", toJSON(Req));
1490 
1491  if (SpecFuzzyFind)
1492  SpecFuzzyFind->NewReq = Req;
1493  if (SpecFuzzyFind && SpecFuzzyFind->Result.valid() && (*SpecReq == Req)) {
1494  vlog("Code complete: speculative fuzzy request matches the actual index "
1495  "request. Waiting for the speculative index results.");
1496  SPAN_ATTACH(Tracer, "Speculative results", true);
1497 
1498  trace::Span WaitSpec("Wait speculative results");
1499  return SpecFuzzyFind->Result.get();
1500  }
1501 
1502  SPAN_ATTACH(Tracer, "Speculative results", false);
1503 
1504  // Run the query against the index.
1505  SymbolSlab::Builder ResultsBuilder;
1506  if (Opts.Index->fuzzyFind(
1507  Req, [&](const Symbol &Sym) { ResultsBuilder.insert(Sym); }))
1508  Incomplete = true;
1509  return std::move(ResultsBuilder).build();
1510  }
1511 
1512  // Merges Sema and Index results where possible, to form CompletionCandidates.
1513  // \p Identifiers is raw identifiers that can also be completion candidates.
1514  // Identifiers are not merged with results from index or sema.
1515  // Groups overloads if desired, to form CompletionCandidate::Bundles. The
1516  // bundles are scored and top results are returned, best to worst.
1517  std::vector<ScoredBundle>
1518  mergeResults(const std::vector<CodeCompletionResult> &SemaResults,
1519  const SymbolSlab &IndexResults,
1520  const std::vector<RawIdentifier> &IdentifierResults) {
1521  trace::Span Tracer("Merge and score results");
1522  std::vector<CompletionCandidate::Bundle> Bundles;
1523  llvm::DenseMap<size_t, size_t> BundleLookup;
1524  auto AddToBundles = [&](const CodeCompletionResult *SemaResult,
1525  const Symbol *IndexResult,
1526  const RawIdentifier *IdentifierResult) {
1527  CompletionCandidate C;
1528  C.SemaResult = SemaResult;
1529  C.IndexResult = IndexResult;
1530  C.IdentifierResult = IdentifierResult;
1531  if (C.IndexResult) {
1532  C.Name = IndexResult->Name;
1533  C.RankedIncludeHeaders = getRankedIncludes(*C.IndexResult);
1534  } else if (C.SemaResult) {
1535  C.Name = Recorder->getName(*SemaResult);
1536  } else {
1537  assert(IdentifierResult);
1538  C.Name = IdentifierResult->Name;
1539  }
1540  if (auto OverloadSet = C.overloadSet(Opts)) {
1541  auto Ret = BundleLookup.try_emplace(OverloadSet, Bundles.size());
1542  if (Ret.second)
1543  Bundles.emplace_back();
1544  Bundles[Ret.first->second].push_back(std::move(C));
1545  } else {
1546  Bundles.emplace_back();
1547  Bundles.back().push_back(std::move(C));
1548  }
1549  };
1550  llvm::DenseSet<const Symbol *> UsedIndexResults;
1551  auto CorrespondingIndexResult =
1552  [&](const CodeCompletionResult &SemaResult) -> const Symbol * {
1553  if (auto SymID =
1554  getSymbolID(SemaResult, Recorder->CCSema->getSourceManager())) {
1555  auto I = IndexResults.find(*SymID);
1556  if (I != IndexResults.end()) {
1557  UsedIndexResults.insert(&*I);
1558  return &*I;
1559  }
1560  }
1561  return nullptr;
1562  };
1563  // Emit all Sema results, merging them with Index results if possible.
1564  for (auto &SemaResult : SemaResults)
1565  AddToBundles(&SemaResult, CorrespondingIndexResult(SemaResult), nullptr);
1566  // Now emit any Index-only results.
1567  for (const auto &IndexResult : IndexResults) {
1568  if (UsedIndexResults.count(&IndexResult))
1569  continue;
1570  AddToBundles(/*SemaResult=*/nullptr, &IndexResult, nullptr);
1571  }
1572  // Emit identifier results.
1573  for (const auto &Ident : IdentifierResults)
1574  AddToBundles(/*SemaResult=*/nullptr, /*IndexResult=*/nullptr, &Ident);
1575  // We only keep the best N results at any time, in "native" format.
1576  TopN<ScoredBundle, ScoredBundleGreater> Top(
1577  Opts.Limit == 0 ? std::numeric_limits<size_t>::max() : Opts.Limit);
1578  for (auto &Bundle : Bundles)
1579  addCandidate(Top, std::move(Bundle));
1580  return std::move(Top).items();
1581  }
1582 
1583  llvm::Optional<float> fuzzyScore(const CompletionCandidate &C) {
1584  // Macros can be very spammy, so we only support prefix completion.
1585  // We won't end up with underfull index results, as macros are sema-only.
1586  if (C.SemaResult && C.SemaResult->Kind == CodeCompletionResult::RK_Macro &&
1587  !C.Name.startswith_lower(Filter->pattern()))
1588  return None;
1589  return Filter->match(C.Name);
1590  }
1591 
1592  // Scores a candidate and adds it to the TopN structure.
1593  void addCandidate(TopN<ScoredBundle, ScoredBundleGreater> &Candidates,
1594  CompletionCandidate::Bundle Bundle) {
1595  SymbolQualitySignals Quality;
1596  SymbolRelevanceSignals Relevance;
1597  Relevance.Context = CCContextKind;
1598  Relevance.Name = Bundle.front().Name;
1599  Relevance.Query = SymbolRelevanceSignals::CodeComplete;
1600  Relevance.FileProximityMatch = FileProximity.getPointer();
1601  if (ScopeProximity)
1602  Relevance.ScopeProximityMatch = ScopeProximity.getPointer();
1603  if (PreferredType)
1604  Relevance.HadContextType = true;
1605  Relevance.ContextWords = &ContextWords;
1606 
1607  auto &First = Bundle.front();
1608  if (auto FuzzyScore = fuzzyScore(First))
1609  Relevance.NameMatch = *FuzzyScore;
1610  else
1611  return;
1613  bool FromIndex = false;
1614  for (const auto &Candidate : Bundle) {
1615  if (Candidate.IndexResult) {
1616  Quality.merge(*Candidate.IndexResult);
1617  Relevance.merge(*Candidate.IndexResult);
1618  Origin |= Candidate.IndexResult->Origin;
1619  FromIndex = true;
1620  if (!Candidate.IndexResult->Type.empty())
1621  Relevance.HadSymbolType |= true;
1622  if (PreferredType &&
1623  PreferredType->raw() == Candidate.IndexResult->Type) {
1624  Relevance.TypeMatchesPreferred = true;
1625  }
1626  }
1627  if (Candidate.SemaResult) {
1628  Quality.merge(*Candidate.SemaResult);
1629  Relevance.merge(*Candidate.SemaResult);
1630  if (PreferredType) {
1631  if (auto CompletionType = OpaqueType::fromCompletionResult(
1632  Recorder->CCSema->getASTContext(), *Candidate.SemaResult)) {
1633  Relevance.HadSymbolType |= true;
1634  if (PreferredType == CompletionType)
1635  Relevance.TypeMatchesPreferred = true;
1636  }
1637  }
1638  Origin |= SymbolOrigin::AST;
1639  }
1640  if (Candidate.IdentifierResult) {
1641  Quality.References = Candidate.IdentifierResult->References;
1642  Relevance.Scope = SymbolRelevanceSignals::FileScope;
1643  Origin |= SymbolOrigin::Identifier;
1644  }
1645  }
1646 
1647  CodeCompletion::Scores Scores;
1648  Scores.Quality = Quality.evaluate();
1649  Scores.Relevance = Relevance.evaluate();
1650  Scores.Total = evaluateSymbolAndRelevance(Scores.Quality, Scores.Relevance);
1651  // NameMatch is in fact a multiplier on total score, so rescoring is sound.
1652  Scores.ExcludingName = Relevance.NameMatch
1653  ? Scores.Total / Relevance.NameMatch
1654  : Scores.Quality;
1655 
1656  dlog("CodeComplete: {0} ({1}) = {2}\n{3}{4}\n", First.Name,
1657  llvm::to_string(Origin), Scores.Total, llvm::to_string(Quality),
1658  llvm::to_string(Relevance));
1659 
1660  NSema += bool(Origin & SymbolOrigin::AST);
1661  NIndex += FromIndex;
1662  NSemaAndIndex += bool(Origin & SymbolOrigin::AST) && FromIndex;
1663  NIdent += bool(Origin & SymbolOrigin::Identifier);
1664  if (Candidates.push({std::move(Bundle), Scores}))
1665  Incomplete = true;
1666  }
1667 
1668  CodeCompletion toCodeCompletion(const CompletionCandidate::Bundle &Bundle) {
1669  llvm::Optional<CodeCompletionBuilder> Builder;
1670  for (const auto &Item : Bundle) {
1671  CodeCompletionString *SemaCCS =
1672  Item.SemaResult ? Recorder->codeCompletionString(*Item.SemaResult)
1673  : nullptr;
1674  if (!Builder)
1675  Builder.emplace(Recorder ? &Recorder->CCSema->getASTContext() : nullptr,
1676  Item, SemaCCS, QueryScopes, *Inserter, FileName,
1677  CCContextKind, Opts,
1678  /*GenerateSnippets=*/!IsUsingDeclaration);
1679  else
1680  Builder->add(Item, SemaCCS);
1681  }
1682  return Builder->build();
1683  }
1684 };
1685 
1686 } // namespace
1687 
1688 clang::CodeCompleteOptions CodeCompleteOptions::getClangCompleteOpts() const {
1689  clang::CodeCompleteOptions Result;
1690  Result.IncludeCodePatterns = EnableSnippets && IncludeCodePatterns;
1691  Result.IncludeMacros = IncludeMacros;
1692  Result.IncludeGlobals = true;
1693  // We choose to include full comments and not do doxygen parsing in
1694  // completion.
1695  // FIXME: ideally, we should support doxygen in some form, e.g. do markdown
1696  // formatting of the comments.
1697  Result.IncludeBriefComments = false;
1698 
1699  // When an is used, Sema is responsible for completing the main file,
1700  // the index can provide results from the preamble.
1701  // Tell Sema not to deserialize the preamble to look for results.
1702  Result.LoadExternal = !Index;
1703  Result.IncludeFixIts = IncludeFixIts;
1704 
1705  return Result;
1706 }
1707 
1708 CompletionPrefix guessCompletionPrefix(llvm::StringRef Content,
1709  unsigned Offset) {
1710  assert(Offset <= Content.size());
1711  StringRef Rest = Content.take_front(Offset);
1712  CompletionPrefix Result;
1713 
1714  // Consume the unqualified name. We only handle ASCII characters.
1715  // isIdentifierBody will let us match "0invalid", but we don't mind.
1716  while (!Rest.empty() && isIdentifierBody(Rest.back()))
1717  Rest = Rest.drop_back();
1718  Result.Name = Content.slice(Rest.size(), Offset);
1719 
1720  // Consume qualifiers.
1721  while (Rest.consume_back("::") && !Rest.endswith(":")) // reject ::::
1722  while (!Rest.empty() && isIdentifierBody(Rest.back()))
1723  Rest = Rest.drop_back();
1724  Result.Qualifier =
1725  Content.slice(Rest.size(), Result.Name.begin() - Content.begin());
1726 
1727  return Result;
1728 }
1729 
1731 codeComplete(PathRef FileName, const tooling::CompileCommand &Command,
1732  const PreambleData *Preamble, llvm::StringRef Contents,
1733  Position Pos, llvm::IntrusiveRefCntPtr<llvm::vfs::FileSystem> VFS,
1734  CodeCompleteOptions Opts, SpeculativeFuzzyFind *SpecFuzzyFind) {
1735  auto Offset = positionToOffset(Contents, Pos);
1736  if (!Offset) {
1737  elog("Code completion position was invalid {0}", Offset.takeError());
1738  return CodeCompleteResult();
1739  }
1740  auto Flow = CodeCompleteFlow(
1741  FileName, Preamble ? Preamble->Includes : IncludeStructure(),
1742  SpecFuzzyFind, Opts);
1743  return (!Preamble || Opts.RunParser == CodeCompleteOptions::NeverParse)
1744  ? std::move(Flow).runWithoutSema(Contents, *Offset, VFS)
1745  : std::move(Flow).run(
1746  {FileName, Command, Preamble, Contents, *Offset, VFS});
1747 }
1748 
1750  const tooling::CompileCommand &Command,
1751  const PreambleData *Preamble,
1752  llvm::StringRef Contents, Position Pos,
1753  llvm::IntrusiveRefCntPtr<llvm::vfs::FileSystem> VFS,
1754  const SymbolIndex *Index) {
1755  auto Offset = positionToOffset(Contents, Pos);
1756  if (!Offset) {
1757  elog("Code completion position was invalid {0}", Offset.takeError());
1758  return SignatureHelp();
1759  }
1760  SignatureHelp Result;
1761  clang::CodeCompleteOptions Options;
1762  Options.IncludeGlobals = false;
1763  Options.IncludeMacros = false;
1764  Options.IncludeCodePatterns = false;
1765  Options.IncludeBriefComments = false;
1766  IncludeStructure PreambleInclusions; // Unused for signatureHelp
1767  semaCodeComplete(
1768  std::make_unique<SignatureHelpCollector>(Options, Index, Result),
1769  Options,
1770  {FileName, Command, Preamble, Contents, *Offset, std::move(VFS)});
1771  return Result;
1772 }
1773 
1774 bool isIndexedForCodeCompletion(const NamedDecl &ND, ASTContext &ASTCtx) {
1775  auto InTopLevelScope = [](const NamedDecl &ND) {
1776  switch (ND.getDeclContext()->getDeclKind()) {
1777  case Decl::TranslationUnit:
1778  case Decl::Namespace:
1779  case Decl::LinkageSpec:
1780  return true;
1781  default:
1782  break;
1783  };
1784  return false;
1785  };
1786  // We only complete symbol's name, which is the same as the name of the
1787  // *primary* template in case of template specializations.
1789  return false;
1790 
1791  if (InTopLevelScope(ND))
1792  return true;
1793 
1794  if (const auto *EnumDecl = dyn_cast<clang::EnumDecl>(ND.getDeclContext()))
1795  return InTopLevelScope(*EnumDecl) && !EnumDecl->isScoped();
1796 
1797  return false;
1798 }
1799 
1801  CompletionItem LSP;
1802  const auto *InsertInclude = Includes.empty() ? nullptr : &Includes[0];
1803  LSP.label = ((InsertInclude && InsertInclude->Insertion)
1804  ? Opts.IncludeIndicator.Insert
1805  : Opts.IncludeIndicator.NoInsert) +
1806  (Opts.ShowOrigins ? "[" + llvm::to_string(Origin) + "]" : "") +
1807  RequiredQualifier + Name + Signature;
1808 
1809  LSP.kind = Kind;
1810  LSP.detail = BundleSize > 1 ? llvm::formatv("[{0} overloads]", BundleSize)
1811  : ReturnType;
1812  LSP.deprecated = Deprecated;
1813  if (InsertInclude)
1814  LSP.detail += "\n" + InsertInclude->Header;
1815  LSP.documentation = Documentation;
1816  LSP.sortText = sortText(Score.Total, Name);
1817  LSP.filterText = Name;
1818  LSP.textEdit = {CompletionTokenRange, RequiredQualifier + Name};
1819  // Merge continuous additionalTextEdits into main edit. The main motivation
1820  // behind this is to help LSP clients, it seems most of them are confused when
1821  // they are provided with additionalTextEdits that are consecutive to main
1822  // edit.
1823  // Note that we store additional text edits from back to front in a line. That
1824  // is mainly to help LSP clients again, so that changes do not effect each
1825  // other.
1826  for (const auto &FixIt : FixIts) {
1827  if (isRangeConsecutive(FixIt.range, LSP.textEdit->range)) {
1828  LSP.textEdit->newText = FixIt.newText + LSP.textEdit->newText;
1829  LSP.textEdit->range.start = FixIt.range.start;
1830  } else {
1831  LSP.additionalTextEdits.push_back(FixIt);
1832  }
1833  }
1834  if (Opts.EnableSnippets)
1835  LSP.textEdit->newText += SnippetSuffix;
1836 
1837  // FIXME(kadircet): Do not even fill insertText after making sure textEdit is
1838  // compatible with most of the editors.
1839  LSP.insertText = LSP.textEdit->newText;
1842  if (InsertInclude && InsertInclude->Insertion)
1843  LSP.additionalTextEdits.push_back(*InsertInclude->Insertion);
1844 
1845  return LSP;
1846 }
1847 
1848 llvm::raw_ostream &operator<<(llvm::raw_ostream &OS, const CodeCompletion &C) {
1849  // For now just lean on CompletionItem.
1850  return OS << C.render(CodeCompleteOptions());
1851 }
1852 
1853 llvm::raw_ostream &operator<<(llvm::raw_ostream &OS,
1854  const CodeCompleteResult &R) {
1855  OS << "CodeCompleteResult: " << R.Completions.size() << (R.HasMore ? "+" : "")
1856  << " (" << getCompletionKindString(R.Context) << ")"
1857  << " items:\n";
1858  for (const auto &C : R.Completions)
1859  OS << C << "\n";
1860  return OS;
1861 }
1862 
1863 } // namespace clangd
1864 } // namespace clang
std::string insertText
A string that should be inserted to a document when selecting this completion.
Definition: Protocol.h:977
std::vector< std::string > AccessibleScopes
Sema * CCSema
llvm::StringRef Name
bool ShowOrigins
Expose origins of completion items in the label (for debugging).
Definition: CodeComplete.h:86
const tooling::CompileCommand & Command
llvm::StringSet collectWords(llvm::StringRef Content)
Collects words from the source code.
Definition: SourceCode.cpp:949
std::shared_ptr< clang::GlobalCodeCompletionAllocator > Allocator
const FunctionDecl * Decl
SignatureQualitySignals Quality
llvm::json::Value toJSON(const FuzzyFindRequest &Request)
Definition: Index.cpp:48
CodeCompletionContext::Kind Context
Definition: CodeComplete.h:218
std::string printQualifiedName(const NamedDecl &ND)
Returns the qualified name of ND.
Definition: AST.cpp:169
llvm::Optional< TextEdit > textEdit
An edit which is applied to a document when selecting this completion.
Definition: Protocol.h:988
llvm::StringRef Contents
Always use text-based completion.
Definition: CodeComplete.h:130
llvm::Optional< SymbolID > getSymbolID(const Decl *D)
Gets the symbol ID for a declaration, if possible.
Definition: AST.cpp:286
static llvm::Optional< OpaqueType > fromType(ASTContext &Ctx, QualType Type)
Construct an instance from a clang::QualType.
The primary text to be inserted is treated as a snippet.
llvm::IntrusiveRefCntPtr< llvm::vfs::FileSystem > VFS
ExpectedMatch Candidate
CompletionItemKind kind
The kind of this completion item.
Definition: Protocol.h:958
size_t lspLength(llvm::StringRef Code)
Definition: SourceCode.cpp:131
bool EnableSnippets
When true, completion items will contain expandable code snippets in completion (e.g.
Definition: CodeComplete.h:46
clang::find_all_symbols::SymbolInfo::SymbolKind SymbolKind
Definition: SymbolInfo.cpp:21
The primary text to be inserted is treated as a plain string.
std::string printNamespaceScope(const DeclContext &DC)
Returns the first enclosing namespace scope starting from DC.
Definition: AST.cpp:278
std::vector< CodeCompletion > Completions
Definition: CodeComplete.h:216
Interface for symbol indexes that can be used for searching or matching symbols among a set of symbol...
Definition: Index.h:85
std::pair< StringRef, StringRef > splitQualifiedName(StringRef QName)
Definition: SourceCode.cpp:599
std::string sortText(float Score, llvm::StringRef Name)
Returns a string that sorts in the same order as (-Score, Tiebreak), for LSP.
Definition: Quality.cpp:481
llvm::StringRef PathRef
A typedef to represent a ref to file path.
Definition: Path.h:23
llvm::Optional< std::string > UnresolvedQualifier
std::vector< CodeCompletionResult > Results
std::string sortText
A string that should be used when comparing this item with other items.
Definition: Protocol.h:969
std::string getDocComment(const ASTContext &Ctx, const CodeCompletionResult &Result, bool CommentsFromHeaders)
Gets a minimally formatted documentation comment of Result, with comment markers stripped.
std::unique_ptr< CompilerInstance > prepareCompilerInstance(std::unique_ptr< clang::CompilerInvocation > CI, const PrecompiledPreamble *Preamble, std::unique_ptr< llvm::MemoryBuffer > Buffer, llvm::IntrusiveRefCntPtr< llvm::vfs::FileSystem > VFS, DiagnosticConsumer &DiagsClient)
Definition: Compiler.cpp:72
Documents should not be synced at all.
std::string documentation
A human-readable string that represents a doc-comment.
Definition: Protocol.h:965
void vlog(const char *Fmt, Ts &&... Vals)
Definition: Logger.h:67
std::vector< TextEdit > additionalTextEdits
An optional array of additional text edits that are applied when selecting this completion.
Definition: Protocol.h:993
void elog(const char *Fmt, Ts &&... Vals)
Definition: Logger.h:56
std::vector< std::string > visibleNamespaces(llvm::StringRef Code, const format::FormatStyle &Style)
Heuristically determine namespaces visible at a point, without parsing Code.
Definition: SourceCode.cpp:901
bool isRangeConsecutive(const Range &Left, const Range &Right)
Definition: SourceCode.cpp:670
CompletionItemKind
The kind of a completion entry.
Definition: Protocol.h:260
std::string getReturnType(const CodeCompletionString &CCS)
Gets detail to be used as the detail field in an LSP completion item.
SignatureHelp signatureHelp(PathRef FileName, const tooling::CompileCommand &Command, const PreambleData *Preamble, llvm::StringRef Contents, Position Pos, llvm::IntrusiveRefCntPtr< llvm::vfs::FileSystem > VFS, const SymbolIndex *Index)
BindArgumentKind Kind
std::string detail
A human-readable string with additional information about this item, like type or symbol information...
Definition: Protocol.h:962
llvm::Optional< float > Score
std::pair< size_t, size_t > offsetToClangLineColumn(llvm::StringRef Code, size_t Offset)
Definition: SourceCode.cpp:589
std::vector< SymbolDetails > getSymbolInfo(ParsedAST &AST, Position Pos)
Get info about symbols at Pos.
Definition: XRefs.cpp:519
TextEdit toTextEdit(const FixItHint &FixIt, const SourceManager &M, const LangOptions &L)
Definition: SourceCode.cpp:661
Position offsetToPosition(llvm::StringRef Code, size_t Offset)
Turn an offset in Code into a [line, column] pair.
Definition: SourceCode.cpp:188
bool isIndexedForCodeCompletion(const NamedDecl &ND, ASTContext &ASTCtx)
IgnoringDiagConsumer IgnoreDiags
std::string filterText
A string that should be used when filtering a set of completion items.
Definition: Protocol.h:973
llvm::Expected< size_t > positionToOffset(llvm::StringRef Code, Position P, bool AllowColumnsBeyondLineLength)
Turn a [line, column] pair into an offset in Code.
Definition: SourceCode.cpp:155
A speculative and asynchronous fuzzy find index request (based on cached request) that can be sent be...
Definition: CodeComplete.h:228
bool deprecated
Indicates if this item is deprecated.
Definition: Protocol.h:996
llvm::unique_function< void()> Action
std::string Signature
void log(const char *Fmt, Ts &&... Vals)
Definition: Logger.h:62
static const char * toString(OffsetEncoding OE)
Definition: Protocol.cpp:1030
#define dlog(...)
Definition: Logger.h:72
llvm::Expected< HeaderFile > toHeaderFile(llvm::StringRef Header, llvm::StringRef HintPath)
Creates a HeaderFile from Header which can be either a URI or a literal include.
Definition: Headers.cpp:77
enum clang::clangd::CodeCompleteOptions::CodeCompletionParse RunParser
const Symbol * IndexResult
PathRef FileName
std::string formatDocumentation(const CodeCompletionString &CCS, llvm::StringRef DocComment)
Assembles formatted documentation for a completion result.
std::string ReturnType
Position Pos
Definition: SourceCode.cpp:772
clang::CodeCompleteOptions getClangCompleteOpts() const
Returns options that can be passed to clang&#39;s completion engine.
std::string SnippetSuffix
Position sourceLocToPosition(const SourceManager &SM, SourceLocation Loc)
Turn a SourceLocation into a [line, column] pair.
Definition: SourceCode.cpp:200
An information message.
format::FormatStyle getFormatStyleForFile(llvm::StringRef File, llvm::StringRef Content, llvm::vfs::FileSystem *FS)
Choose the clang-format style we should apply to a certain file.
Definition: SourceCode.cpp:693
CodeCompleteResult codeComplete(PathRef FileName, const tooling::CompileCommand &Command, const PreambleData *Preamble, llvm::StringRef Contents, Position Pos, llvm::IntrusiveRefCntPtr< llvm::vfs::FileSystem > VFS, CodeCompleteOptions Opts, SpeculativeFuzzyFind *SpecFuzzyFind)
float evaluateSymbolAndRelevance(float SymbolQuality, float SymbolRelevance)
Combine symbol quality and relevance into a single score.
Definition: Quality.cpp:463
CodeCompletionBuilder Builder
size_t Offset
std::string getDeclComment(const ASTContext &Ctx, const NamedDecl &Decl)
Similar to getDocComment, but returns the comment for a NamedDecl.
Represents the signature of a callable.
Definition: Protocol.h:1054
bool isExplicitTemplateSpecialization(const NamedDecl *D)
Indicates if D is an explicit template specialization, e.g.
Definition: AST.cpp:153
const PreambleData * Preamble
std::unique_ptr< PPCallbacks > collectIncludeStructureCallback(const SourceManager &SM, IncludeStructure *Out)
Returns a PPCallback that visits all inclusions in the main file.
Definition: Headers.cpp:113
llvm::SmallVector< llvm::StringRef, 1 > RankedIncludeHeaders
===– Representation.cpp - ClangDoc Representation --------—*- C++ -*-===//
static URISchemeRegistry::Add< TestScheme > X(TestScheme::Scheme, "Test schema")
unsigned References
std::string label
The label of this completion item.
Definition: Protocol.h:954
CompletionItem render(const CodeCompleteOptions &) const
struct clang::clangd::CodeCompleteOptions::IncludeInsertionIndicator IncludeIndicator
CharSourceRange Range
SourceRange for the file name.
llvm::SmallVector< llvm::StringRef, 1 > getRankedIncludes(const Symbol &Sym)
Definition: Headers.cpp:97
CodeCompletionTUInfo CCTUInfo
std::unique_ptr< CompilerInvocation > buildCompilerInvocation(const ParseInputs &Inputs, clang::DiagnosticConsumer &D, std::vector< std::string > *CC1Args)
Builds compiler invocation that could be used to build AST or preamble.
Definition: Compiler.cpp:44
void getSignature(const CodeCompletionString &CCS, std::string *Signature, std::string *Snippet, std::string *RequiredQualifiers, bool CompletingPattern)
Formats the signature for an item, as a display string and snippet.
const CodeCompletionResult * SemaResult
std::vector< const char * > Expected
const RawIdentifier * IdentifierResult
const Expr * E
static llvm::Expected< std::string > resolve(const URI &U, llvm::StringRef HintPath="")
Resolves the absolute path of U.
Definition: URI.cpp:233
llvm::Optional< FixItHint > FixIt
Indicates if the symbol is deprecated.
Definition: Symbol.h:121
static std::string join(ArrayRef< SpecialMemberFunctionsCheck::SpecialMemberFunctionKind > SMFS, llvm::StringRef AndOr)
IncludeStructure Includes
Definition: Preamble.h:56
CompletionPrefix guessCompletionPrefix(llvm::StringRef Content, unsigned Offset)
llvm::raw_ostream & operator<<(llvm::raw_ostream &OS, const CodeCompletion &C)
The parsed preamble and associated data.
Definition: Preamble.h:45
InsertTextFormat insertTextFormat
The format of the insert text.
Definition: Protocol.h:981
llvm::StringMap< unsigned > collectIdentifiers(llvm::StringRef Content, const format::FormatStyle &Style)
Collects identifiers with counts in the source code.
Definition: SourceCode.cpp:735
CodeCompletionContext CCContext
#define SPAN_ATTACH(S, Name, Expr)
Attach a key-value pair to a Span event.
Definition: Trace.h:97
llvm::Optional< SymbolID > IDForDoc
static llvm::Optional< OpaqueType > fromCompletionResult(ASTContext &Ctx, const CodeCompletionResult &R)
Create a type from a code completion result.
Range halfOpenToRange(const SourceManager &SM, CharSourceRange R)
Definition: SourceCode.cpp:581
const SymbolIndex * Index
Definition: Dexp.cpp:84