clang-tools-extra/clangd/FindSymbols.cpp

   1 //===--- FindSymbols.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 #include "FindSymbols.h"
   9
  10 #include "AST.h"
  11 #include "FuzzyMatch.h"
  12 #include "ParsedAST.h"
  13 #include "Quality.h"
  14 #include "SourceCode.h"
  15 #include "index/Index.h"
  16 #include "support/Logger.h"
  17 #include "clang/AST/DeclTemplate.h"
  18 #include "clang/Index/IndexSymbol.h"
  19 #include "llvm/ADT/ArrayRef.h"
  20 #include "llvm/ADT/STLExtras.h"
  21 #include "llvm/ADT/SmallVector.h"
  22 #include "llvm/ADT/StringRef.h"
  23 #include <limits>
  24 #include <optional>
  25 #include <tuple>
  26
  27 #define DEBUG_TYPE "FindSymbols"
  28
  29 namespace clang {
  30 namespace clangd {
  31
  32 namespace {
  33 using ScoredSymbolInfo = std::pair<float, SymbolInformation>;
  34 struct ScoredSymbolGreater {
  35   bool operator()(const ScoredSymbolInfo &L, const ScoredSymbolInfo &R) {
  36     if (L.first != R.first)
  37       return L.first > R.first;
  38     return L.second.name < R.second.name; // Earlier name is better.
  39   }
  40 };
  41
  42 // Returns true if \p Query can be found as a sub-sequence inside \p Scope.
  43 bool approximateScopeMatch(llvm::StringRef Scope, llvm::StringRef Query) {
  44   assert(Scope.empty() || Scope.ends_with("::"));
  45   assert(Query.empty() || Query.ends_with("::"));
  46   while (!Scope.empty() && !Query.empty()) {
  47     auto Colons = Scope.find("::");
  48     assert(Colons != llvm::StringRef::npos);
  49
  50     llvm::StringRef LeadingSpecifier = Scope.slice(0, Colons + 2);
  51     Scope = Scope.slice(Colons + 2, llvm::StringRef::npos);
  52     Query.consume_front(LeadingSpecifier);
  53   }
  54   return Query.empty();
  55 }
  56
  57 } // namespace
  58
  59 llvm::Expected<Location> indexToLSPLocation(const SymbolLocation &Loc,
  60                                             llvm::StringRef TUPath) {
  61   auto Path = URI::resolve(Loc.FileURI, TUPath);
  62   if (!Path)
  63     return error("Could not resolve path for file '{0}': {1}", Loc.FileURI,
  64                  Path.takeError());
  65   Location L;
  66   L.uri = URIForFile::canonicalize(*Path, TUPath);
  67   Position Start, End;
  68   Start.line = Loc.Start.line();
  69   Start.character = Loc.Start.column();
  70   End.line = Loc.End.line();
  71   End.character = Loc.End.column();
  72   L.range = {Start, End};
  73   return L;
  74 }
  75
  76 llvm::Expected<Location> symbolToLocation(const Symbol &Sym,
  77                                           llvm::StringRef TUPath) {
  78   // Prefer the definition over e.g. a function declaration in a header
  79   return indexToLSPLocation(
  80       Sym.Definition ? Sym.Definition : Sym.CanonicalDeclaration, TUPath);
  81 }
  82
  83 llvm::Expected<std::vector<SymbolInformation>>
  84 getWorkspaceSymbols(llvm::StringRef Query, int Limit,
  85                     const SymbolIndex *const Index, llvm::StringRef HintPath) {
  86   std::vector<SymbolInformation> Result;
  87   if (!Index)
  88     return Result;
  89
  90   // Lookup for qualified names are performed as:
  91   // - Exact namespaces are boosted by the index.
  92   // - Approximate matches are (sub-scope match) included via AnyScope logic.
  93   // - Non-matching namespaces (no sub-scope match) are post-filtered.
  94   auto Names = splitQualifiedName(Query);
  95
  96   FuzzyFindRequest Req;
  97   Req.Query = std::string(Names.second);
  98
  99   // FuzzyFind doesn't want leading :: qualifier.
 100   auto HasLeadingColons = Names.first.consume_front("::");
 101   // Limit the query to specific namespace if it is fully-qualified.
 102   Req.AnyScope = !HasLeadingColons;
 103   // Boost symbols from desired namespace.
 104   if (HasLeadingColons || !Names.first.empty())
 105     Req.Scopes = {std::string(Names.first)};
 106   if (Limit) {
 107     Req.Limit = Limit;
 108     // If we are boosting a specific scope allow more results to be retrieved,
 109     // since some symbols from preferred namespaces might not make the cut.
 110     if (Req.AnyScope && !Req.Scopes.empty())
 111       *Req.Limit *= 5;
 112   }
 113   TopN<ScoredSymbolInfo, ScoredSymbolGreater> Top(
 114       Req.Limit ? *Req.Limit : std::numeric_limits<size_t>::max());
 115   FuzzyMatcher Filter(Req.Query);
 116
 117   Index->fuzzyFind(Req, [HintPath, &Top, &Filter, AnyScope = Req.AnyScope,
 118                          ReqScope = Names.first](const Symbol &Sym) {
 119     llvm::StringRef Scope = Sym.Scope;
 120     // Fuzzyfind might return symbols from irrelevant namespaces if query was
 121     // not fully-qualified, drop those.
 122     if (AnyScope && !approximateScopeMatch(Scope, ReqScope))
 123       return;
 124
 125     auto Loc = symbolToLocation(Sym, HintPath);
 126     if (!Loc) {
 127       log("Workspace symbols: {0}", Loc.takeError());
 128       return;
 129     }
 130
 131     SymbolQualitySignals Quality;
 132     Quality.merge(Sym);
 133     SymbolRelevanceSignals Relevance;
 134     Relevance.Name = Sym.Name;
 135     Relevance.Query = SymbolRelevanceSignals::Generic;
 136     // If symbol and request scopes do not match exactly, apply a penalty.
 137     Relevance.InBaseClass = AnyScope && Scope != ReqScope;
 138     if (auto NameMatch = Filter.match(Sym.Name))
 139       Relevance.NameMatch = *NameMatch;
 140     else {
 141       log("Workspace symbol: {0} didn't match query {1}", Sym.Name,
 142           Filter.pattern());
 143       return;
 144     }
 145     Relevance.merge(Sym);
 146     auto QualScore = Quality.evaluateHeuristics();
 147     auto RelScore = Relevance.evaluateHeuristics();
 148     auto Score = evaluateSymbolAndRelevance(QualScore, RelScore);
 149     dlog("FindSymbols: {0}{1} = {2}\n{3}{4}\n", Sym.Scope, Sym.Name, Score,
 150          Quality, Relevance);
 151
 152     SymbolInformation Info;
 153     Info.name = (Sym.Name + Sym.TemplateSpecializationArgs).str();
 154     Info.kind = indexSymbolKindToSymbolKind(Sym.SymInfo.Kind);
 155     Info.location = *Loc;
 156     Scope.consume_back("::");
 157     Info.containerName = Scope.str();
 158
 159     // Exposed score excludes fuzzy-match component, for client-side re-ranking.
 160     Info.score = Relevance.NameMatch > std::numeric_limits<float>::epsilon()
 161                      ? Score / Relevance.NameMatch
 162                      : QualScore;
 163     Top.push({Score, std::move(Info)});
 164   });
 165   for (auto &R : std::move(Top).items())
 166     Result.push_back(std::move(R.second));
 167   return Result;
 168 }
 169
 170 namespace {
 171 std::string getSymbolName(ASTContext &Ctx, const NamedDecl &ND) {
 172   // Print `MyClass(Category)` instead of `Category` and `MyClass()` instead
 173   // of `anonymous`.
 174   if (const auto *Container = dyn_cast<ObjCContainerDecl>(&ND))
 175     return printObjCContainer(*Container);
 176   // Differentiate between class and instance methods: print `-foo` instead of
 177   // `foo` and `+sharedInstance` instead of `sharedInstance`.
 178   if (const auto *Method = dyn_cast<ObjCMethodDecl>(&ND)) {
 179     std::string Name;
 180     llvm::raw_string_ostream OS(Name);
 181
 182     OS << (Method->isInstanceMethod() ? '-' : '+');
 183     Method->getSelector().print(OS);
 184
 185     OS.flush();
 186     return Name;
 187   }
 188   return printName(Ctx, ND);
 189 }
 190
 191 std::string getSymbolDetail(ASTContext &Ctx, const NamedDecl &ND) {
 192   PrintingPolicy P(Ctx.getPrintingPolicy());
 193   P.SuppressScope = true;
 194   P.SuppressUnwrittenScope = true;
 195   P.AnonymousTagLocations = false;
 196   P.PolishForDeclaration = true;
 197   std::string Detail;
 198   llvm::raw_string_ostream OS(Detail);
 199   if (ND.getDescribedTemplateParams()) {
 200     OS << "template ";
 201   }
 202   if (const auto *VD = dyn_cast<ValueDecl>(&ND)) {
 203     // FIXME: better printing for dependent type
 204     if (isa<CXXConstructorDecl>(VD)) {
 205       std::string ConstructorType = VD->getType().getAsString(P);
 206       // Print constructor type as "(int)" instead of "void (int)".
 207       llvm::StringRef WithoutVoid = ConstructorType;
 208       WithoutVoid.consume_front("void ");
 209       OS << WithoutVoid;
 210     } else if (!isa<CXXDestructorDecl>(VD)) {
 211       VD->getType().print(OS, P);
 212     }
 213   } else if (const auto *TD = dyn_cast<TagDecl>(&ND)) {
 214     OS << TD->getKindName();
 215   } else if (isa<TypedefNameDecl>(&ND)) {
 216     OS << "type alias";
 217   } else if (isa<ConceptDecl>(&ND)) {
 218     OS << "concept";
 219   }
 220   return std::move(OS.str());
 221 }
 222
 223 std::optional<DocumentSymbol> declToSym(ASTContext &Ctx, const NamedDecl &ND) {
 224   auto &SM = Ctx.getSourceManager();
 225
 226   SourceLocation BeginLoc = ND.getBeginLoc();
 227   SourceLocation EndLoc = ND.getEndLoc();
 228   const auto SymbolRange =
 229       toHalfOpenFileRange(SM, Ctx.getLangOpts(), {BeginLoc, EndLoc});
 230   if (!SymbolRange)
 231     return std::nullopt;
 232
 233   index::SymbolInfo SymInfo = index::getSymbolInfo(&ND);
 234   // FIXME: This is not classifying constructors, destructors and operators
 235   // correctly.
 236   SymbolKind SK = indexSymbolKindToSymbolKind(SymInfo.Kind);
 237
 238   DocumentSymbol SI;
 239   SI.name = getSymbolName(Ctx, ND);
 240   SI.kind = SK;
 241   SI.deprecated = ND.isDeprecated();
 242   SI.range = Range{sourceLocToPosition(SM, SymbolRange->getBegin()),
 243                    sourceLocToPosition(SM, SymbolRange->getEnd())};
 244   SI.detail = getSymbolDetail(Ctx, ND);
 245
 246   SourceLocation NameLoc = ND.getLocation();
 247   SourceLocation FallbackNameLoc;
 248   if (NameLoc.isMacroID()) {
 249     if (isSpelledInSource(NameLoc, SM)) {
 250       // Prefer the spelling loc, but save the expansion loc as a fallback.
 251       FallbackNameLoc = SM.getExpansionLoc(NameLoc);
 252       NameLoc = SM.getSpellingLoc(NameLoc);
 253     } else {
 254       NameLoc = SM.getExpansionLoc(NameLoc);
 255     }
 256   }
 257   auto ComputeSelectionRange = [&](SourceLocation L) -> Range {
 258     Position NameBegin = sourceLocToPosition(SM, L);
 259     Position NameEnd = sourceLocToPosition(
 260         SM, Lexer::getLocForEndOfToken(L, 0, SM, Ctx.getLangOpts()));
 261     return Range{NameBegin, NameEnd};
 262   };
 263
 264   SI.selectionRange = ComputeSelectionRange(NameLoc);
 265   if (!SI.range.contains(SI.selectionRange) && FallbackNameLoc.isValid()) {
 266     // 'selectionRange' must be contained in 'range'. In cases where clang
 267     // reports unrelated ranges, we first try falling back to the expansion
 268     // loc for the selection range.
 269     SI.selectionRange = ComputeSelectionRange(FallbackNameLoc);
 270   }
 271   if (!SI.range.contains(SI.selectionRange)) {
 272     // If the containment relationship still doesn't hold, throw away
 273     // 'range' and use 'selectionRange' for both.
 274     SI.range = SI.selectionRange;
 275   }
 276   return SI;
 277 }
 278
 279 /// A helper class to build an outline for the parse AST. It traverses the AST
 280 /// directly instead of using RecursiveASTVisitor (RAV) for three main reasons:
 281 ///    - there is no way to keep RAV from traversing subtrees we are not
 282 ///      interested in. E.g. not traversing function locals or implicit template
 283 ///      instantiations.
 284 ///    - it's easier to combine results of recursive passes,
 285 ///    - visiting decls is actually simple, so we don't hit the complicated
 286 ///      cases that RAV mostly helps with (types, expressions, etc.)
 287 class DocumentOutline {
 288   // A DocumentSymbol we're constructing.
 289   // We use this instead of DocumentSymbol directly so that we can keep track
 290   // of the nodes we insert for macros.
 291   class SymBuilder {
 292     std::vector<SymBuilder> Children;
 293     DocumentSymbol Symbol; // Symbol.children is empty, use Children instead.
 294     // Macro expansions that this node or its parents are associated with.
 295     // (Thus we will never create further children for these expansions).
 296     llvm::SmallVector<SourceLocation> EnclosingMacroLoc;
 297
 298   public:
 299     DocumentSymbol build() && {
 300       for (SymBuilder &C : Children) {
 301         Symbol.children.push_back(std::move(C).build());
 302         // Expand range to ensure children nest properly, which editors expect.
 303         // This can fix some edge-cases in the AST, but is vital for macros.
 304         // A macro expansion "contains" AST node if it covers the node's primary
 305         // location, but it may not span the node's whole range.
 306         Symbol.range.start =
 307             std::min(Symbol.range.start, Symbol.children.back().range.start);
 308         Symbol.range.end =
 309             std::max(Symbol.range.end, Symbol.children.back().range.end);
 310       }
 311       return std::move(Symbol);
 312     }
 313
 314     // Add a symbol as a child of the current one.
 315     SymBuilder &addChild(DocumentSymbol S) {
 316       Children.emplace_back();
 317       Children.back().EnclosingMacroLoc = EnclosingMacroLoc;
 318       Children.back().Symbol = std::move(S);
 319       return Children.back();
 320     }
 321
 322     // Get an appropriate container for children of this symbol that were
 323     // expanded from a macro (whose spelled name is Tok).
 324     //
 325     // This may return:
 326     //  - a macro symbol child of this (either new or previously created)
 327     //  - this scope itself, if it *is* the macro symbol or is nested within it
 328     SymBuilder &inMacro(const syntax::Token &Tok, const SourceManager &SM,
 329                         std::optional<syntax::TokenBuffer::Expansion> Exp) {
 330       if (llvm::is_contained(EnclosingMacroLoc, Tok.location()))
 331         return *this;
 332       // If there's an existing child for this macro, we expect it to be last.
 333       if (!Children.empty() && !Children.back().EnclosingMacroLoc.empty() &&
 334           Children.back().EnclosingMacroLoc.back() == Tok.location())
 335         return Children.back();
 336
 337       DocumentSymbol Sym;
 338       Sym.name = Tok.text(SM).str();
 339       Sym.kind = SymbolKind::Null; // There's no suitable kind!
 340       Sym.range = Sym.selectionRange =
 341           halfOpenToRange(SM, Tok.range(SM).toCharRange(SM));
 342
 343       // FIXME: Exp is currently unavailable for nested expansions.
 344       if (Exp) {
 345         // Full range covers the macro args.
 346         Sym.range = halfOpenToRange(SM, CharSourceRange::getCharRange(
 347                                             Exp->Spelled.front().location(),
 348                                             Exp->Spelled.back().endLocation()));
 349         // Show macro args as detail.
 350         llvm::raw_string_ostream OS(Sym.detail);
 351         const syntax::Token *Prev = nullptr;
 352         for (const auto &Tok : Exp->Spelled.drop_front()) {
 353           // Don't dump arbitrarily long macro args.
 354           if (OS.tell() > 80) {
 355             OS << " ...)";
 356             break;
 357           }
 358           if (Prev && Prev->endLocation() != Tok.location())
 359             OS << ' ';
 360           OS << Tok.text(SM);
 361           Prev = &Tok;
 362         }
 363       }
 364       SymBuilder &Child = addChild(std::move(Sym));
 365       Child.EnclosingMacroLoc.push_back(Tok.location());
 366       return Child;
 367     }
 368   };
 369
 370 public:
 371   DocumentOutline(ParsedAST &AST) : AST(AST) {}
 372
 373   /// Builds the document outline for the generated AST.
 374   std::vector<DocumentSymbol> build() {
 375     SymBuilder Root;
 376     for (auto &TopLevel : AST.getLocalTopLevelDecls())
 377       traverseDecl(TopLevel, Root);
 378     return std::move(std::move(Root).build().children);
 379   }
 380
 381 private:
 382   enum class VisitKind { No, OnlyDecl, OnlyChildren, DeclAndChildren };
 383
 384   void traverseDecl(Decl *D, SymBuilder &Parent) {
 385     // Skip symbols which do not originate from the main file.
 386     if (!isInsideMainFile(D->getLocation(), AST.getSourceManager()))
 387       return;
 388
 389     if (auto *Templ = llvm::dyn_cast<TemplateDecl>(D)) {
 390       // TemplatedDecl might be null, e.g. concepts.
 391       if (auto *TD = Templ->getTemplatedDecl())
 392         D = TD;
 393     }
 394
 395     VisitKind Visit = shouldVisit(D);
 396     if (Visit == VisitKind::No)
 397       return;
 398
 399     if (Visit == VisitKind::OnlyChildren)
 400       return traverseChildren(D, Parent);
 401
 402     auto *ND = llvm::cast<NamedDecl>(D);
 403     auto Sym = declToSym(AST.getASTContext(), *ND);
 404     if (!Sym)
 405       return;
 406     SymBuilder &MacroParent = possibleMacroContainer(D->getLocation(), Parent);
 407     SymBuilder &Child = MacroParent.addChild(std::move(*Sym));
 408
 409     if (Visit == VisitKind::OnlyDecl)
 410       return;
 411
 412     assert(Visit == VisitKind::DeclAndChildren && "Unexpected VisitKind");
 413     traverseChildren(ND, Child);
 414   }
 415
 416   // Determines where a decl should appear in the DocumentSymbol hierarchy.
 417   //
 418   // This is usually a direct child of the relevant AST parent.
 419   // But we may also insert nodes for macros. Given:
 420   //   #define DECLARE_INT(V) int v;
 421   //   namespace a { DECLARE_INT(x) }
 422   // We produce:
 423   //   Namespace a
 424   //     Macro DECLARE_INT(x)
 425   //       Variable x
 426   //
 427   // In the absence of macros, this method simply returns Parent.
 428   // Otherwise it may return a macro expansion node instead.
 429   // Each macro only has at most one node in the hierarchy, even if it expands
 430   // to multiple decls.
 431   SymBuilder &possibleMacroContainer(SourceLocation TargetLoc,
 432                                      SymBuilder &Parent) {
 433     const auto &SM = AST.getSourceManager();
 434     // Look at the path of macro-callers from the token to the main file.
 435     // Note that along these paths we see the "outer" macro calls first.
 436     SymBuilder *CurParent = &Parent;
 437     for (SourceLocation Loc = TargetLoc; Loc.isMacroID();
 438          Loc = SM.getImmediateMacroCallerLoc(Loc)) {
 439       // Find the virtual macro body that our token is being substituted into.
 440       FileID MacroBody;
 441       if (SM.isMacroArgExpansion(Loc)) {
 442         // Loc is part of a macro arg being substituted into a macro body.
 443         MacroBody = SM.getFileID(SM.getImmediateExpansionRange(Loc).getBegin());
 444       } else {
 445         // Loc is already in the macro body.
 446         MacroBody = SM.getFileID(Loc);
 447       }
 448       // The macro body is being substituted for a macro expansion, whose
 449       // first token is the name of the macro.
 450       SourceLocation MacroName =
 451           SM.getSLocEntry(MacroBody).getExpansion().getExpansionLocStart();
 452       // Only include the macro expansion in the outline if it was written
 453       // directly in the main file, rather than expanded from another macro.
 454       if (!MacroName.isValid() || !MacroName.isFileID())
 455         continue;
 456       // All conditions satisfied, add the macro.
 457       if (auto *Tok = AST.getTokens().spelledTokenContaining(MacroName))
 458         CurParent = &CurParent->inMacro(
 459             *Tok, SM, AST.getTokens().expansionStartingAt(Tok));
 460     }
 461     return *CurParent;
 462   }
 463
 464   void traverseChildren(Decl *D, SymBuilder &Builder) {
 465     auto *Scope = llvm::dyn_cast<DeclContext>(D);
 466     if (!Scope)
 467       return;
 468     for (auto *C : Scope->decls())
 469       traverseDecl(C, Builder);
 470   }
 471
 472   VisitKind shouldVisit(Decl *D) {
 473     if (D->isImplicit())
 474       return VisitKind::No;
 475
 476     if (llvm::isa<LinkageSpecDecl>(D) || llvm::isa<ExportDecl>(D))
 477       return VisitKind::OnlyChildren;
 478
 479     if (!llvm::isa<NamedDecl>(D))
 480       return VisitKind::No;
 481
 482     if (auto *Func = llvm::dyn_cast<FunctionDecl>(D)) {
 483       // Some functions are implicit template instantiations, those should be
 484       // ignored.
 485       if (auto *Info = Func->getTemplateSpecializationInfo()) {
 486         if (!Info->isExplicitInstantiationOrSpecialization())
 487           return VisitKind::No;
 488       }
 489       // Only visit the function itself, do not visit the children (i.e.
 490       // function parameters, etc.)
 491       return VisitKind::OnlyDecl;
 492     }
 493     // Handle template instantiations. We have three cases to consider:
 494     //   - explicit instantiations, e.g. 'template class std::vector<int>;'
 495     //     Visit the decl itself (it's present in the code), but not the
 496     //     children.
 497     //   - implicit instantiations, i.e. not written by the user.
 498     //     Do not visit at all, they are not present in the code.
 499     //   - explicit specialization, e.g. 'template <> class vector<bool> {};'
 500     //     Visit both the decl and its children, both are written in the code.
 501     if (auto *TemplSpec = llvm::dyn_cast<ClassTemplateSpecializationDecl>(D)) {
 502       if (TemplSpec->isExplicitInstantiationOrSpecialization())
 503         return TemplSpec->isExplicitSpecialization()
 504                    ? VisitKind::DeclAndChildren
 505                    : VisitKind::OnlyDecl;
 506       return VisitKind::No;
 507     }
 508     if (auto *TemplSpec = llvm::dyn_cast<VarTemplateSpecializationDecl>(D)) {
 509       if (TemplSpec->isExplicitInstantiationOrSpecialization())
 510         return TemplSpec->isExplicitSpecialization()
 511                    ? VisitKind::DeclAndChildren
 512                    : VisitKind::OnlyDecl;
 513       return VisitKind::No;
 514     }
 515     // For all other cases, visit both the children and the decl.
 516     return VisitKind::DeclAndChildren;
 517   }
 518
 519   ParsedAST &AST;
 520 };
 521
 522 struct PragmaMarkSymbol {
 523   DocumentSymbol DocSym;
 524   bool IsGroup;
 525 };
 526
 527 /// Merge in `PragmaMarkSymbols`, sorted ascending by range, into the given
 528 /// `DocumentSymbol` tree.
 529 void mergePragmas(DocumentSymbol &Root, ArrayRef<PragmaMarkSymbol> Pragmas) {
 530   while (!Pragmas.empty()) {
 531     // We'll figure out where the Pragmas.front() should go.
 532     PragmaMarkSymbol P = std::move(Pragmas.front());
 533     Pragmas = Pragmas.drop_front();
 534     DocumentSymbol *Cur = &Root;
 535     while (Cur->range.contains(P.DocSym.range)) {
 536       bool Swapped = false;
 537       for (auto &C : Cur->children) {
 538         // We assume at most 1 child can contain the pragma (as pragmas are on
 539         // a single line, and children have disjoint ranges).
 540         if (C.range.contains(P.DocSym.range)) {
 541           Cur = &C;
 542           Swapped = true;
 543           break;
 544         }
 545       }
 546       // Cur is the parent of P since none of the children contain P.
 547       if (!Swapped)
 548         break;
 549     }
 550     // Pragma isn't a group so we can just insert it and we are done.
 551     if (!P.IsGroup) {
 552       Cur->children.emplace_back(std::move(P.DocSym));
 553       continue;
 554     }
 555     // Pragma is a group, so we need to figure out where it terminates:
 556     // - If the next Pragma is not contained in Cur, P owns all of its
 557     //   parent's children which occur after P.
 558     // - If the next pragma is contained in Cur but actually belongs to one
 559     //   of the parent's children, we temporarily skip over it and look at
 560     //   the next pragma to decide where we end.
 561     // - Otherwise nest all of its parent's children which occur after P but
 562     //   before the next pragma.
 563     bool TerminatedByNextPragma = false;
 564     for (auto &NextPragma : Pragmas) {
 565       // If we hit a pragma outside of Cur, the rest will be outside as well.
 566       if (!Cur->range.contains(NextPragma.DocSym.range))
 567         break;
 568
 569       // NextPragma cannot terminate P if it is nested inside a child, look for
 570       // the next one.
 571       if (llvm::any_of(Cur->children, [&NextPragma](const auto &Child) {
 572             return Child.range.contains(NextPragma.DocSym.range);
 573           }))
 574         continue;
 575
 576       // Pragma owns all the children between P and NextPragma
 577       auto It = llvm::partition(Cur->children,
 578                                 [&P, &NextPragma](const auto &S) -> bool {
 579                                   return !(P.DocSym.range < S.range &&
 580                                            S.range < NextPragma.DocSym.range);
 581                                 });
 582       P.DocSym.children.assign(make_move_iterator(It),
 583                                make_move_iterator(Cur->children.end()));
 584       Cur->children.erase(It, Cur->children.end());
 585       TerminatedByNextPragma = true;
 586       break;
 587     }
 588     if (!TerminatedByNextPragma) {
 589       // P is terminated by the end of current symbol, hence it owns all the
 590       // children after P.
 591       auto It = llvm::partition(Cur->children, [&P](const auto &S) -> bool {
 592         return !(P.DocSym.range < S.range);
 593       });
 594       P.DocSym.children.assign(make_move_iterator(It),
 595                                make_move_iterator(Cur->children.end()));
 596       Cur->children.erase(It, Cur->children.end());
 597     }
 598     // Update the range for P to cover children and append to Cur.
 599     for (DocumentSymbol &Sym : P.DocSym.children)
 600       unionRanges(P.DocSym.range, Sym.range);
 601     Cur->children.emplace_back(std::move(P.DocSym));
 602   }
 603 }
 604
 605 PragmaMarkSymbol markToSymbol(const PragmaMark &P) {
 606   StringRef Name = StringRef(P.Trivia).trim();
 607   bool IsGroup = false;
 608   // "-\s+<group name>" or "<name>" after an initial trim. The former is
 609   // considered a group, the latter just a mark. Like Xcode, we don't consider
 610   // `-Foo` to be a group (space(s) after the `-` is required).
 611   //
 612   // We need to include a name here, otherwise editors won't properly render the
 613   // symbol.
 614   StringRef MaybeGroupName = Name;
 615   if (MaybeGroupName.consume_front("-") &&
 616       (MaybeGroupName.ltrim() != MaybeGroupName || MaybeGroupName.empty())) {
 617     Name = MaybeGroupName.empty() ? "(unnamed group)" : MaybeGroupName.ltrim();
 618     IsGroup = true;
 619   } else if (Name.empty()) {
 620     Name = "(unnamed mark)";
 621   }
 622   DocumentSymbol Sym;
 623   Sym.name = Name.str();
 624   Sym.kind = SymbolKind::File;
 625   Sym.range = P.Rng;
 626   Sym.selectionRange = P.Rng;
 627   return {Sym, IsGroup};
 628 }
 629
 630 std::vector<DocumentSymbol> collectDocSymbols(ParsedAST &AST) {
 631   std::vector<DocumentSymbol> Syms = DocumentOutline(AST).build();
 632
 633   const auto &PragmaMarks = AST.getMarks();
 634   if (PragmaMarks.empty())
 635     return Syms;
 636
 637   std::vector<PragmaMarkSymbol> Pragmas;
 638   Pragmas.reserve(PragmaMarks.size());
 639   for (const auto &P : PragmaMarks)
 640     Pragmas.push_back(markToSymbol(P));
 641   Range EntireFile = {
 642       {0, 0},
 643       {std::numeric_limits<int>::max(), std::numeric_limits<int>::max()}};
 644   DocumentSymbol Root;
 645   Root.children = std::move(Syms);
 646   Root.range = EntireFile;
 647   mergePragmas(Root, llvm::ArrayRef(Pragmas));
 648   return Root.children;
 649 }
 650
 651 } // namespace
 652
 653 llvm::Expected<std::vector<DocumentSymbol>> getDocumentSymbols(ParsedAST &AST) {
 654   return collectDocSymbols(AST);
 655 }
 656
 657 } // namespace clangd
 658 } // namespace clang