clang-tools  10.0.0
FindTarget.cpp
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1 //===--- FindTarget.cpp - What does an AST node refer to? -----------------===//
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 #include "FindTarget.h"
10 #include "AST.h"
11 #include "Logger.h"
12 #include "clang/AST/ASTTypeTraits.h"
13 #include "clang/AST/Decl.h"
14 #include "clang/AST/DeclCXX.h"
15 #include "clang/AST/DeclTemplate.h"
16 #include "clang/AST/DeclVisitor.h"
17 #include "clang/AST/DeclarationName.h"
18 #include "clang/AST/Expr.h"
19 #include "clang/AST/ExprCXX.h"
20 #include "clang/AST/ExprObjC.h"
21 #include "clang/AST/NestedNameSpecifier.h"
22 #include "clang/AST/PrettyPrinter.h"
23 #include "clang/AST/RecursiveASTVisitor.h"
24 #include "clang/AST/StmtVisitor.h"
25 #include "clang/AST/TemplateBase.h"
26 #include "clang/AST/Type.h"
27 #include "clang/AST/TypeLoc.h"
28 #include "clang/AST/TypeLocVisitor.h"
29 #include "clang/Basic/LangOptions.h"
30 #include "clang/Basic/OperatorKinds.h"
31 #include "clang/Basic/SourceLocation.h"
32 #include "llvm/ADT/STLExtras.h"
33 #include "llvm/ADT/SmallVector.h"
34 #include "llvm/Support/Casting.h"
35 #include "llvm/Support/Compiler.h"
36 #include "llvm/Support/raw_ostream.h"
37 #include <utility>
38 #include <vector>
39 
40 namespace clang {
41 namespace clangd {
42 namespace {
43 using ast_type_traits::DynTypedNode;
44 
45 LLVM_ATTRIBUTE_UNUSED std::string
46 nodeToString(const ast_type_traits::DynTypedNode &N) {
47  std::string S = N.getNodeKind().asStringRef();
48  {
49  llvm::raw_string_ostream OS(S);
50  OS << ": ";
51  N.print(OS, PrintingPolicy(LangOptions()));
52  }
53  std::replace(S.begin(), S.end(), '\n', ' ');
54  return S;
55 }
56 
57 // Given a dependent type and a member name, heuristically resolve the
58 // name to one or more declarations.
59 // The current heuristic is simply to look up the name in the primary
60 // template. This is a heuristic because the template could potentially
61 // have specializations that declare different members.
62 // Multiple declarations could be returned if the name is overloaded
63 // (e.g. an overloaded method in the primary template).
64 // This heuristic will give the desired answer in many cases, e.g.
65 // for a call to vector<T>::size().
66 // The name to look up is provided in the form of a factory that takes
67 // an ASTContext, because an ASTContext may be needed to obtain the
68 // name (e.g. if it's an operator name), but the caller may not have
69 // access to an ASTContext.
70 std::vector<const NamedDecl *> getMembersReferencedViaDependentName(
71  const Type *T,
72  llvm::function_ref<DeclarationName(ASTContext &)> NameFactory,
73  bool IsNonstaticMember) {
74  if (!T)
75  return {};
76  if (auto *ICNT = T->getAs<InjectedClassNameType>()) {
77  T = ICNT->getInjectedSpecializationType().getTypePtrOrNull();
78  }
79  auto *TST = T->getAs<TemplateSpecializationType>();
80  if (!TST)
81  return {};
82  const ClassTemplateDecl *TD = dyn_cast_or_null<ClassTemplateDecl>(
83  TST->getTemplateName().getAsTemplateDecl());
84  if (!TD)
85  return {};
86  CXXRecordDecl *RD = TD->getTemplatedDecl();
87  if (!RD->hasDefinition())
88  return {};
89  RD = RD->getDefinition();
90  DeclarationName Name = NameFactory(RD->getASTContext());
91  return RD->lookupDependentName(Name, [=](const NamedDecl *D) {
92  return IsNonstaticMember ? D->isCXXInstanceMember()
93  : !D->isCXXInstanceMember();
94  });
95 }
96 
97 // Given the type T of a dependent expression that appears of the LHS of a "->",
98 // heuristically find a corresponding pointee type in whose scope we could look
99 // up the name appearing on the RHS.
100 const Type *getPointeeType(const Type *T) {
101  if (!T)
102  return nullptr;
103 
104  if (T->isPointerType()) {
105  return T->getAs<PointerType>()->getPointeeType().getTypePtrOrNull();
106  }
107 
108  // Try to handle smart pointer types.
109 
110  // Look up operator-> in the primary template. If we find one, it's probably a
111  // smart pointer type.
112  auto ArrowOps = getMembersReferencedViaDependentName(
113  T,
114  [](ASTContext &Ctx) {
115  return Ctx.DeclarationNames.getCXXOperatorName(OO_Arrow);
116  },
117  /*IsNonStaticMember=*/true);
118  if (ArrowOps.empty())
119  return nullptr;
120 
121  // Getting the return type of the found operator-> method decl isn't useful,
122  // because we discarded template arguments to perform lookup in the primary
123  // template scope, so the return type would just have the form U* where U is a
124  // template parameter type.
125  // Instead, just handle the common case where the smart pointer type has the
126  // form of SmartPtr<X, ...>, and assume X is the pointee type.
127  auto *TST = T->getAs<TemplateSpecializationType>();
128  if (!TST)
129  return nullptr;
130  if (TST->getNumArgs() == 0)
131  return nullptr;
132  const TemplateArgument &FirstArg = TST->getArg(0);
133  if (FirstArg.getKind() != TemplateArgument::Type)
134  return nullptr;
135  return FirstArg.getAsType().getTypePtrOrNull();
136 }
137 
138 const NamedDecl *getTemplatePattern(const NamedDecl *D) {
139  if (const CXXRecordDecl *CRD = dyn_cast<CXXRecordDecl>(D)) {
140  return CRD->getTemplateInstantiationPattern();
141  } else if (const FunctionDecl *FD = dyn_cast<FunctionDecl>(D)) {
142  return FD->getTemplateInstantiationPattern();
143  } else if (auto *VD = dyn_cast<VarDecl>(D)) {
144  // Hmm: getTIP returns its arg if it's not an instantiation?!
145  VarDecl *T = VD->getTemplateInstantiationPattern();
146  return (T == D) ? nullptr : T;
147  } else if (const auto *ED = dyn_cast<EnumDecl>(D)) {
148  return ED->getInstantiatedFromMemberEnum();
149  } else if (isa<FieldDecl>(D) || isa<TypedefNameDecl>(D)) {
150  if (const auto *Parent = llvm::dyn_cast<NamedDecl>(D->getDeclContext()))
151  if (const DeclContext *ParentPat =
152  dyn_cast_or_null<DeclContext>(getTemplatePattern(Parent)))
153  for (const NamedDecl *BaseND : ParentPat->lookup(D->getDeclName()))
154  if (!BaseND->isImplicit() && BaseND->getKind() == D->getKind())
155  return BaseND;
156  } else if (const auto *ECD = dyn_cast<EnumConstantDecl>(D)) {
157  if (const auto *ED = dyn_cast<EnumDecl>(ECD->getDeclContext())) {
158  if (const EnumDecl *Pattern = ED->getInstantiatedFromMemberEnum()) {
159  for (const NamedDecl *BaseECD : Pattern->lookup(ECD->getDeclName()))
160  return BaseECD;
161  }
162  }
163  }
164  return nullptr;
165 }
166 
167 // TargetFinder locates the entities that an AST node refers to.
168 //
169 // Typically this is (possibly) one declaration and (possibly) one type, but
170 // may be more:
171 // - for ambiguous nodes like OverloadExpr
172 // - if we want to include e.g. both typedefs and the underlying type
173 //
174 // This is organized as a set of mutually recursive helpers for particular node
175 // types, but for most nodes this is a short walk rather than a deep traversal.
176 //
177 // It's tempting to do e.g. typedef resolution as a second normalization step,
178 // after finding the 'primary' decl etc. But we do this monolithically instead
179 // because:
180 // - normalization may require these traversals again (e.g. unwrapping a
181 // typedef reveals a decltype which must be traversed)
182 // - it doesn't simplify that much, e.g. the first stage must still be able
183 // to yield multiple decls to handle OverloadExpr
184 // - there are cases where it's required for correctness. e.g:
185 // template<class X> using pvec = vector<x*>; pvec<int> x;
186 // There's no Decl `pvec<int>`, we must choose `pvec<X>` or `vector<int*>`
187 // and both are lossy. We must know upfront what the caller ultimately wants.
188 //
189 // FIXME: improve common dependent scope using name lookup in primary templates.
190 // e.g. template<typename T> int foo() { return std::vector<T>().size(); }
191 // formally size() is unresolved, but the primary template is a good guess.
192 // This affects:
193 // - DependentTemplateSpecializationType,
194 // - DependentNameType
195 // - UnresolvedUsingValueDecl
196 // - UnresolvedUsingTypenameDecl
197 struct TargetFinder {
198  using RelSet = DeclRelationSet;
199  using Rel = DeclRelation;
200 
201 private:
202  llvm::SmallDenseMap<const NamedDecl *,
203  std::pair<RelSet, /*InsertionOrder*/ size_t>>
204  Decls;
205  RelSet Flags;
206 
207  template <typename T> void debug(T &Node, RelSet Flags) {
208  dlog("visit [{0}] {1}", Flags,
209  nodeToString(ast_type_traits::DynTypedNode::create(Node)));
210  }
211 
212  void report(const NamedDecl *D, RelSet Flags) {
213  dlog("--> [{0}] {1}", Flags,
214  nodeToString(ast_type_traits::DynTypedNode::create(*D)));
215  auto It = Decls.try_emplace(D, std::make_pair(Flags, Decls.size()));
216  // If already exists, update the flags.
217  if (!It.second)
218  It.first->second.first |= Flags;
219  }
220 
221 public:
222  llvm::SmallVector<std::pair<const NamedDecl *, RelSet>, 1> takeDecls() const {
223  using ValTy = std::pair<const NamedDecl *, RelSet>;
224  llvm::SmallVector<ValTy, 1> Result;
225  Result.resize(Decls.size());
226  for (const auto &Elem : Decls)
227  Result[Elem.second.second] = {Elem.first, Elem.second.first};
228  return Result;
229  }
230 
231  void add(const Decl *Dcl, RelSet Flags) {
232  const NamedDecl *D = llvm::dyn_cast<NamedDecl>(Dcl);
233  if (!D)
234  return;
235  debug(*D, Flags);
236  if (const UsingDirectiveDecl *UDD = llvm::dyn_cast<UsingDirectiveDecl>(D))
237  D = UDD->getNominatedNamespaceAsWritten();
238 
239  if (const TypedefNameDecl *TND = dyn_cast<TypedefNameDecl>(D)) {
240  add(TND->getUnderlyingType(), Flags | Rel::Underlying);
241  Flags |= Rel::Alias; // continue with the alias.
242  } else if (const UsingDecl *UD = dyn_cast<UsingDecl>(D)) {
243  for (const UsingShadowDecl *S : UD->shadows())
244  add(S->getUnderlyingDecl(), Flags | Rel::Underlying);
245  Flags |= Rel::Alias; // continue with the alias.
246  } else if (const auto *NAD = dyn_cast<NamespaceAliasDecl>(D)) {
247  add(NAD->getUnderlyingDecl(), Flags | Rel::Underlying);
248  Flags |= Rel::Alias; // continue with the alias
249  } else if (const UsingShadowDecl *USD = dyn_cast<UsingShadowDecl>(D)) {
250  // Include the using decl, but don't traverse it. This may end up
251  // including *all* shadows, which we don't want.
252  report(USD->getUsingDecl(), Flags | Rel::Alias);
253  // Shadow decls are synthetic and not themselves interesting.
254  // Record the underlying decl instead, if allowed.
255  D = USD->getTargetDecl();
256  Flags |= Rel::Underlying; // continue with the underlying decl.
257  }
258 
259  if (const Decl *Pat = getTemplatePattern(D)) {
260  assert(Pat != D);
261  add(Pat, Flags | Rel::TemplatePattern);
262  // Now continue with the instantiation.
264  }
265 
266  report(D, Flags);
267  }
268 
269  void add(const Stmt *S, RelSet Flags) {
270  if (!S)
271  return;
272  debug(*S, Flags);
273  struct Visitor : public ConstStmtVisitor<Visitor> {
274  TargetFinder &Outer;
275  RelSet Flags;
276  Visitor(TargetFinder &Outer, RelSet Flags) : Outer(Outer), Flags(Flags) {}
277 
278  void VisitCallExpr(const CallExpr *CE) {
279  Outer.add(CE->getCalleeDecl(), Flags);
280  }
281  void VisitDeclRefExpr(const DeclRefExpr *DRE) {
282  const Decl *D = DRE->getDecl();
283  // UsingShadowDecl allows us to record the UsingDecl.
284  // getFoundDecl() returns the wrong thing in other cases (templates).
285  if (auto *USD = llvm::dyn_cast<UsingShadowDecl>(DRE->getFoundDecl()))
286  D = USD;
287  Outer.add(D, Flags);
288  }
289  void VisitMemberExpr(const MemberExpr *ME) {
290  const Decl *D = ME->getMemberDecl();
291  if (auto *USD =
292  llvm::dyn_cast<UsingShadowDecl>(ME->getFoundDecl().getDecl()))
293  D = USD;
294  Outer.add(D, Flags);
295  }
296  void VisitOverloadExpr(const OverloadExpr *OE) {
297  for (auto *D : OE->decls())
298  Outer.add(D, Flags);
299  }
300  void VisitSizeOfPackExpr(const SizeOfPackExpr *SE) {
301  Outer.add(SE->getPack(), Flags);
302  }
303  void VisitCXXConstructExpr(const CXXConstructExpr *CCE) {
304  Outer.add(CCE->getConstructor(), Flags);
305  }
306  void VisitDesignatedInitExpr(const DesignatedInitExpr *DIE) {
307  for (const DesignatedInitExpr::Designator &D :
308  llvm::reverse(DIE->designators()))
309  if (D.isFieldDesignator()) {
310  Outer.add(D.getField(), Flags);
311  // We don't know which designator was intended, we assume the outer.
312  break;
313  }
314  }
315  void
316  VisitCXXDependentScopeMemberExpr(const CXXDependentScopeMemberExpr *E) {
317  const Type *BaseType = E->getBaseType().getTypePtrOrNull();
318  if (E->isArrow()) {
319  BaseType = getPointeeType(BaseType);
320  }
321  for (const NamedDecl *D : getMembersReferencedViaDependentName(
322  BaseType, [E](ASTContext &) { return E->getMember(); },
323  /*IsNonstaticMember=*/true)) {
324  Outer.add(D, Flags);
325  }
326  }
327  void VisitDependentScopeDeclRefExpr(const DependentScopeDeclRefExpr *E) {
328  for (const NamedDecl *D : getMembersReferencedViaDependentName(
329  E->getQualifier()->getAsType(),
330  [E](ASTContext &) { return E->getDeclName(); },
331  /*IsNonstaticMember=*/false)) {
332  Outer.add(D, Flags);
333  }
334  }
335  void VisitObjCIvarRefExpr(const ObjCIvarRefExpr *OIRE) {
336  Outer.add(OIRE->getDecl(), Flags);
337  }
338  void VisitObjCMessageExpr(const ObjCMessageExpr *OME) {
339  Outer.add(OME->getMethodDecl(), Flags);
340  }
341  void VisitObjCPropertyRefExpr(const ObjCPropertyRefExpr *OPRE) {
342  if (OPRE->isExplicitProperty())
343  Outer.add(OPRE->getExplicitProperty(), Flags);
344  else {
345  if (OPRE->isMessagingGetter())
346  Outer.add(OPRE->getImplicitPropertyGetter(), Flags);
347  if (OPRE->isMessagingSetter())
348  Outer.add(OPRE->getImplicitPropertySetter(), Flags);
349  }
350  }
351  void VisitObjCProtocolExpr(const ObjCProtocolExpr *OPE) {
352  Outer.add(OPE->getProtocol(), Flags);
353  }
354  void VisitOpaqueValueExpr(const OpaqueValueExpr *OVE) {
355  Outer.add(OVE->getSourceExpr(), Flags);
356  }
357  void VisitPseudoObjectExpr(const PseudoObjectExpr *POE) {
358  Outer.add(POE->getSyntacticForm(), Flags);
359  }
360  };
361  Visitor(*this, Flags).Visit(S);
362  }
363 
364  void add(QualType T, RelSet Flags) {
365  if (T.isNull())
366  return;
367  debug(T, Flags);
368  struct Visitor : public TypeVisitor<Visitor> {
369  TargetFinder &Outer;
370  RelSet Flags;
371  Visitor(TargetFinder &Outer, RelSet Flags) : Outer(Outer), Flags(Flags) {}
372 
373  void VisitTagType(const TagType *TT) {
374  Outer.add(TT->getAsTagDecl(), Flags);
375  }
376  void VisitDecltypeType(const DecltypeType *DTT) {
377  Outer.add(DTT->getUnderlyingType(), Flags | Rel::Underlying);
378  }
379  void VisitDeducedType(const DeducedType *DT) {
380  // FIXME: In practice this doesn't work: the AutoType you find inside
381  // TypeLoc never has a deduced type. https://llvm.org/PR42914
382  Outer.add(DT->getDeducedType(), Flags | Rel::Underlying);
383  }
384  void VisitDeducedTemplateSpecializationType(
385  const DeducedTemplateSpecializationType *DTST) {
386  // FIXME: This is a workaround for https://llvm.org/PR42914,
387  // which is causing DTST->getDeducedType() to be empty. We
388  // fall back to the template pattern and miss the instantiation
389  // even when it's known in principle. Once that bug is fixed,
390  // this method can be removed (the existing handling in
391  // VisitDeducedType() is sufficient).
392  if (auto *TD = DTST->getTemplateName().getAsTemplateDecl())
393  Outer.add(TD->getTemplatedDecl(), Flags | Rel::TemplatePattern);
394  }
395  void VisitTypedefType(const TypedefType *TT) {
396  Outer.add(TT->getDecl(), Flags);
397  }
398  void
399  VisitTemplateSpecializationType(const TemplateSpecializationType *TST) {
400  // Have to handle these case-by-case.
401 
402  // templated type aliases: there's no specialized/instantiated using
403  // decl to point to. So try to find a decl for the underlying type
404  // (after substitution), and failing that point to the (templated) using
405  // decl.
406  if (TST->isTypeAlias()) {
407  Outer.add(TST->getAliasedType(), Flags | Rel::Underlying);
408  // Don't *traverse* the alias, which would result in traversing the
409  // template of the underlying type.
410  Outer.report(
411  TST->getTemplateName().getAsTemplateDecl()->getTemplatedDecl(),
412  Flags | Rel::Alias | Rel::TemplatePattern);
413  }
414  // specializations of template template parameters aren't instantiated
415  // into decls, so they must refer to the parameter itself.
416  else if (const auto *Parm =
417  llvm::dyn_cast_or_null<TemplateTemplateParmDecl>(
418  TST->getTemplateName().getAsTemplateDecl()))
419  Outer.add(Parm, Flags);
420  // class template specializations have a (specialized) CXXRecordDecl.
421  else if (const CXXRecordDecl *RD = TST->getAsCXXRecordDecl())
422  Outer.add(RD, Flags); // add(Decl) will despecialize if needed.
423  else {
424  // fallback: the (un-specialized) declaration from primary template.
425  if (auto *TD = TST->getTemplateName().getAsTemplateDecl())
426  Outer.add(TD->getTemplatedDecl(), Flags | Rel::TemplatePattern);
427  }
428  }
429  void VisitTemplateTypeParmType(const TemplateTypeParmType *TTPT) {
430  Outer.add(TTPT->getDecl(), Flags);
431  }
432  void VisitObjCInterfaceType(const ObjCInterfaceType *OIT) {
433  Outer.add(OIT->getDecl(), Flags);
434  }
435  void VisitObjCObjectType(const ObjCObjectType *OOT) {
436  // FIXME: ObjCObjectTypeLoc has no children for the protocol list, so
437  // there is no node in id<Foo> that refers to ObjCProtocolDecl Foo.
438  if (OOT->isObjCQualifiedId() && OOT->getNumProtocols() == 1)
439  Outer.add(OOT->getProtocol(0), Flags);
440  }
441  };
442  Visitor(*this, Flags).Visit(T.getTypePtr());
443  }
444 
445  void add(const NestedNameSpecifier *NNS, RelSet Flags) {
446  if (!NNS)
447  return;
448  debug(*NNS, Flags);
449  switch (NNS->getKind()) {
451  return;
453  add(NNS->getAsNamespace(), Flags);
454  return;
455  case NestedNameSpecifier::NamespaceAlias:
456  add(NNS->getAsNamespaceAlias(), Flags);
457  return;
458  case NestedNameSpecifier::TypeSpec:
459  case NestedNameSpecifier::TypeSpecWithTemplate:
460  add(QualType(NNS->getAsType(), 0), Flags);
461  return;
462  case NestedNameSpecifier::Global:
463  // This should be TUDecl, but we can't get a pointer to it!
464  return;
465  case NestedNameSpecifier::Super:
466  add(NNS->getAsRecordDecl(), Flags);
467  return;
468  }
469  llvm_unreachable("unhandled NestedNameSpecifier::SpecifierKind");
470  }
471 
472  void add(const CXXCtorInitializer *CCI, RelSet Flags) {
473  if (!CCI)
474  return;
475  debug(*CCI, Flags);
476 
477  if (CCI->isAnyMemberInitializer())
478  add(CCI->getAnyMember(), Flags);
479  // Constructor calls contain a TypeLoc node, so we don't handle them here.
480  }
481 };
482 
483 } // namespace
484 
485 llvm::SmallVector<std::pair<const NamedDecl *, DeclRelationSet>, 1>
486 allTargetDecls(const ast_type_traits::DynTypedNode &N) {
487  dlog("allTargetDecls({0})", nodeToString(N));
488  TargetFinder Finder;
490  if (const Decl *D = N.get<Decl>())
491  Finder.add(D, Flags);
492  else if (const Stmt *S = N.get<Stmt>())
493  Finder.add(S, Flags);
494  else if (const NestedNameSpecifierLoc *NNSL = N.get<NestedNameSpecifierLoc>())
495  Finder.add(NNSL->getNestedNameSpecifier(), Flags);
496  else if (const NestedNameSpecifier *NNS = N.get<NestedNameSpecifier>())
497  Finder.add(NNS, Flags);
498  else if (const TypeLoc *TL = N.get<TypeLoc>())
499  Finder.add(TL->getType(), Flags);
500  else if (const QualType *QT = N.get<QualType>())
501  Finder.add(*QT, Flags);
502  else if (const CXXCtorInitializer *CCI = N.get<CXXCtorInitializer>())
503  Finder.add(CCI, Flags);
504 
505  return Finder.takeDecls();
506 }
507 
508 llvm::SmallVector<const NamedDecl *, 1>
509 targetDecl(const ast_type_traits::DynTypedNode &N, DeclRelationSet Mask) {
510  llvm::SmallVector<const NamedDecl *, 1> Result;
511  for (const auto &Entry : allTargetDecls(N)) {
512  if (!(Entry.second & ~Mask))
513  Result.push_back(Entry.first);
514  }
515  return Result;
516 }
517 
518 llvm::SmallVector<const NamedDecl *, 1>
520  assert(!(Mask & (DeclRelation::TemplatePattern |
522  "explicitRefenceTargets handles templates on its own");
523  auto Decls = allTargetDecls(N);
524 
525  // We prefer to return template instantiation, but fallback to template
526  // pattern if instantiation is not available.
528 
529  llvm::SmallVector<const NamedDecl *, 1> TemplatePatterns;
530  llvm::SmallVector<const NamedDecl *, 1> Targets;
531  bool SeenTemplateInstantiations = false;
532  for (auto &D : Decls) {
533  if (D.second & ~Mask)
534  continue;
535  if (D.second & DeclRelation::TemplatePattern) {
536  TemplatePatterns.push_back(D.first);
537  continue;
538  }
540  SeenTemplateInstantiations = true;
541  Targets.push_back(D.first);
542  }
543  if (!SeenTemplateInstantiations)
544  Targets.insert(Targets.end(), TemplatePatterns.begin(),
545  TemplatePatterns.end());
546  return Targets;
547 }
548 
549 namespace {
550 llvm::SmallVector<ReferenceLoc, 2> refInDecl(const Decl *D) {
551  struct Visitor : ConstDeclVisitor<Visitor> {
552  llvm::SmallVector<ReferenceLoc, 2> Refs;
553 
554  void VisitUsingDirectiveDecl(const UsingDirectiveDecl *D) {
555  // We want to keep it as non-declaration references, as the
556  // "using namespace" declaration doesn't have a name.
557  Refs.push_back(ReferenceLoc{D->getQualifierLoc(),
558  D->getIdentLocation(),
559  /*IsDecl=*/false,
560  {D->getNominatedNamespaceAsWritten()}});
561  }
562 
563  void VisitUsingDecl(const UsingDecl *D) {
564  // "using ns::identifier;" is a non-declaration reference.
565  Refs.push_back(
566  ReferenceLoc{D->getQualifierLoc(), D->getLocation(), /*IsDecl=*/false,
567  explicitReferenceTargets(DynTypedNode::create(*D),
569  }
570 
571  void VisitNamespaceAliasDecl(const NamespaceAliasDecl *D) {
572  // For namespace alias, "namespace Foo = Target;", we add two references.
573  // Add a declaration reference for Foo.
574  VisitNamedDecl(D);
575  // Add a non-declaration reference for Target.
576  Refs.push_back(ReferenceLoc{D->getQualifierLoc(),
577  D->getTargetNameLoc(),
578  /*IsDecl=*/false,
579  {D->getAliasedNamespace()}});
580  }
581 
582  void VisitNamedDecl(const NamedDecl *ND) {
583  // FIXME: decide on how to surface destructors when we need them.
584  if (llvm::isa<CXXDestructorDecl>(ND))
585  return;
586  // Filter anonymous decls, name location will point outside the name token
587  // and the clients are not prepared to handle that.
588  if (ND->getDeclName().isIdentifier() &&
589  !ND->getDeclName().getAsIdentifierInfo())
590  return;
591  Refs.push_back(ReferenceLoc{getQualifierLoc(*ND),
592  ND->getLocation(),
593  /*IsDecl=*/true,
594  {ND}});
595  }
596  };
597 
598  Visitor V;
599  V.Visit(D);
600  return V.Refs;
601 }
602 
603 llvm::SmallVector<ReferenceLoc, 2> refInExpr(const Expr *E) {
604  struct Visitor : ConstStmtVisitor<Visitor> {
605  // FIXME: handle more complicated cases, e.g. ObjC, designated initializers.
606  llvm::SmallVector<ReferenceLoc, 2> Refs;
607 
608  void VisitDeclRefExpr(const DeclRefExpr *E) {
609  Refs.push_back(ReferenceLoc{E->getQualifierLoc(),
610  E->getNameInfo().getLoc(),
611  /*IsDecl=*/false,
612  {E->getFoundDecl()}});
613  }
614 
615  void VisitMemberExpr(const MemberExpr *E) {
616  Refs.push_back(ReferenceLoc{E->getQualifierLoc(),
617  E->getMemberNameInfo().getLoc(),
618  /*IsDecl=*/false,
619  {E->getFoundDecl()}});
620  }
621 
622  void VisitOverloadExpr(const OverloadExpr *E) {
623  Refs.push_back(ReferenceLoc{E->getQualifierLoc(),
624  E->getNameInfo().getLoc(),
625  /*IsDecl=*/false,
626  llvm::SmallVector<const NamedDecl *, 1>(
627  E->decls().begin(), E->decls().end())});
628  }
629 
630  void VisitSizeOfPackExpr(const SizeOfPackExpr *E) {
631  Refs.push_back(ReferenceLoc{NestedNameSpecifierLoc(),
632  E->getPackLoc(),
633  /*IsDecl=*/false,
634  {E->getPack()}});
635  }
636  };
637 
638  Visitor V;
639  V.Visit(E);
640  return V.Refs;
641 }
642 
643 llvm::SmallVector<ReferenceLoc, 2> refInTypeLoc(TypeLoc L) {
644  struct Visitor : TypeLocVisitor<Visitor> {
645  llvm::Optional<ReferenceLoc> Ref;
646 
647  void VisitElaboratedTypeLoc(ElaboratedTypeLoc L) {
648  // We only know about qualifier, rest if filled by inner locations.
649  Visit(L.getNamedTypeLoc().getUnqualifiedLoc());
650  // Fill in the qualifier.
651  if (!Ref)
652  return;
653  assert(!Ref->Qualifier.hasQualifier() && "qualifier already set");
654  Ref->Qualifier = L.getQualifierLoc();
655  }
656 
657  void VisitTagTypeLoc(TagTypeLoc L) {
658  Ref = ReferenceLoc{NestedNameSpecifierLoc(),
659  L.getNameLoc(),
660  /*IsDecl=*/false,
661  {L.getDecl()}};
662  }
663 
664  void VisitTemplateTypeParmTypeLoc(TemplateTypeParmTypeLoc L) {
665  Ref = ReferenceLoc{NestedNameSpecifierLoc(),
666  L.getNameLoc(),
667  /*IsDecl=*/false,
668  {L.getDecl()}};
669  }
670 
671  void VisitTemplateSpecializationTypeLoc(TemplateSpecializationTypeLoc L) {
672  // We must ensure template type aliases are included in results if they
673  // were written in the source code, e.g. in
674  // template <class T> using valias = vector<T>;
675  // ^valias<int> x;
676  // 'explicitReferenceTargets' will return:
677  // 1. valias with mask 'Alias'.
678  // 2. 'vector<int>' with mask 'Underlying'.
679  // we want to return only #1 in this case.
680  Ref = ReferenceLoc{
681  NestedNameSpecifierLoc(), L.getTemplateNameLoc(), /*IsDecl=*/false,
682  explicitReferenceTargets(DynTypedNode::create(L.getType()),
684  }
685  void VisitDeducedTemplateSpecializationTypeLoc(
686  DeducedTemplateSpecializationTypeLoc L) {
687  Ref = ReferenceLoc{
688  NestedNameSpecifierLoc(), L.getNameLoc(), /*IsDecl=*/false,
689  explicitReferenceTargets(DynTypedNode::create(L.getType()),
691  }
692 
693  void VisitDependentTemplateSpecializationTypeLoc(
694  DependentTemplateSpecializationTypeLoc L) {
695  Ref = ReferenceLoc{
696  L.getQualifierLoc(), L.getTemplateNameLoc(), /*IsDecl=*/false,
697  explicitReferenceTargets(DynTypedNode::create(L.getType()), {})};
698  }
699 
700  void VisitDependentNameTypeLoc(DependentNameTypeLoc L) {
701  Ref = ReferenceLoc{
702  L.getQualifierLoc(), L.getNameLoc(), /*IsDecl=*/false,
703  explicitReferenceTargets(DynTypedNode::create(L.getType()), {})};
704  }
705 
706  void VisitTypedefTypeLoc(TypedefTypeLoc L) {
707  Ref = ReferenceLoc{NestedNameSpecifierLoc(),
708  L.getNameLoc(),
709  /*IsDecl=*/false,
710  {L.getTypedefNameDecl()}};
711  }
712  };
713 
714  Visitor V;
715  V.Visit(L.getUnqualifiedLoc());
716  if (!V.Ref)
717  return {};
718  return {*V.Ref};
719 }
720 
721 class ExplicitReferenceCollector
722  : public RecursiveASTVisitor<ExplicitReferenceCollector> {
723 public:
724  ExplicitReferenceCollector(llvm::function_ref<void(ReferenceLoc)> Out)
725  : Out(Out) {
726  assert(Out);
727  }
728 
729  bool VisitTypeLoc(TypeLoc TTL) {
730  if (TypeLocsToSkip.count(TTL.getBeginLoc().getRawEncoding()))
731  return true;
732  visitNode(DynTypedNode::create(TTL));
733  return true;
734  }
735 
736  bool TraverseElaboratedTypeLoc(ElaboratedTypeLoc L) {
737  // ElaboratedTypeLoc will reports information for its inner type loc.
738  // Otherwise we loose information about inner types loc's qualifier.
739  TypeLoc Inner = L.getNamedTypeLoc().getUnqualifiedLoc();
740  TypeLocsToSkip.insert(Inner.getBeginLoc().getRawEncoding());
741  return RecursiveASTVisitor::TraverseElaboratedTypeLoc(L);
742  }
743 
744  bool VisitExpr(Expr *E) {
745  visitNode(DynTypedNode::create(*E));
746  return true;
747  }
748 
749  // We re-define Traverse*, since there's no corresponding Visit*.
750  // TemplateArgumentLoc is the only way to get locations for references to
751  // template template parameters.
752  bool TraverseTemplateArgumentLoc(TemplateArgumentLoc A) {
753  switch (A.getArgument().getKind()) {
754  case TemplateArgument::Template:
755  case TemplateArgument::TemplateExpansion:
756  reportReference(ReferenceLoc{A.getTemplateQualifierLoc(),
757  A.getTemplateNameLoc(),
758  /*IsDecl=*/false,
759  {A.getArgument()
760  .getAsTemplateOrTemplatePattern()
761  .getAsTemplateDecl()}},
762  DynTypedNode::create(A.getArgument()));
763  break;
765  break; // FIXME: can this actually happen in TemplateArgumentLoc?
766  case TemplateArgument::Integral:
768  case TemplateArgument::NullPtr:
769  break; // no references.
770  case TemplateArgument::Pack:
772  case TemplateArgument::Expression:
773  break; // Handled by VisitType and VisitExpression.
774  };
775  return RecursiveASTVisitor::TraverseTemplateArgumentLoc(A);
776  }
777 
778  bool VisitDecl(Decl *D) {
779  visitNode(DynTypedNode::create(*D));
780  return true;
781  }
782 
783  // We have to use Traverse* because there is no corresponding Visit*.
784  bool TraverseNestedNameSpecifierLoc(NestedNameSpecifierLoc L) {
785  if (!L.getNestedNameSpecifier())
786  return true;
787  visitNode(DynTypedNode::create(L));
788  // Inner type is missing information about its qualifier, skip it.
789  if (auto TL = L.getTypeLoc())
790  TypeLocsToSkip.insert(TL.getBeginLoc().getRawEncoding());
791  return RecursiveASTVisitor::TraverseNestedNameSpecifierLoc(L);
792  }
793 
794  bool TraverseConstructorInitializer(CXXCtorInitializer *Init) {
795  visitNode(DynTypedNode::create(*Init));
796  return RecursiveASTVisitor::TraverseConstructorInitializer(Init);
797  }
798 
799 private:
800  /// Obtain information about a reference directly defined in \p N. Does not
801  /// recurse into child nodes, e.g. do not expect references for constructor
802  /// initializers
803  ///
804  /// Any of the fields in the returned structure can be empty, but not all of
805  /// them, e.g.
806  /// - for implicitly generated nodes (e.g. MemberExpr from range-based-for),
807  /// source location information may be missing,
808  /// - for dependent code, targets may be empty.
809  ///
810  /// (!) For the purposes of this function declarations are not considered to
811  /// be references. However, declarations can have references inside them,
812  /// e.g. 'namespace foo = std' references namespace 'std' and this
813  /// function will return the corresponding reference.
814  llvm::SmallVector<ReferenceLoc, 2> explicitReference(DynTypedNode N) {
815  if (auto *D = N.get<Decl>())
816  return refInDecl(D);
817  if (auto *E = N.get<Expr>())
818  return refInExpr(E);
819  if (auto *NNSL = N.get<NestedNameSpecifierLoc>()) {
820  // (!) 'DeclRelation::Alias' ensures we do not loose namespace aliases.
821  return {ReferenceLoc{
822  NNSL->getPrefix(), NNSL->getLocalBeginLoc(), false,
824  DynTypedNode::create(*NNSL->getNestedNameSpecifier()),
826  }
827  if (const TypeLoc *TL = N.get<TypeLoc>())
828  return refInTypeLoc(*TL);
829  if (const CXXCtorInitializer *CCI = N.get<CXXCtorInitializer>()) {
830  // Other type initializers (e.g. base initializer) are handled by visiting
831  // the typeLoc.
832  if (CCI->isAnyMemberInitializer()) {
833  return {ReferenceLoc{NestedNameSpecifierLoc(),
834  CCI->getMemberLocation(),
835  /*IsDecl=*/false,
836  {CCI->getAnyMember()}}};
837  }
838  }
839  // We do not have location information for other nodes (QualType, etc)
840  return {};
841  }
842 
843  void visitNode(DynTypedNode N) {
844  for (const auto &R : explicitReference(N))
845  reportReference(R, N);
846  }
847 
848  void reportReference(const ReferenceLoc &Ref, DynTypedNode N) {
849  // Our promise is to return only references from the source code. If we lack
850  // location information, skip these nodes.
851  // Normally this should not happen in practice, unless there are bugs in the
852  // traversals or users started the traversal at an implicit node.
853  if (Ref.NameLoc.isInvalid()) {
854  dlog("invalid location at node {0}", nodeToString(N));
855  return;
856  }
857  Out(Ref);
858  }
859 
860  llvm::function_ref<void(ReferenceLoc)> Out;
861  /// TypeLocs starting at these locations must be skipped, see
862  /// TraverseElaboratedTypeSpecifierLoc for details.
863  llvm::DenseSet</*SourceLocation*/ unsigned> TypeLocsToSkip;
864 };
865 } // namespace
866 
867 void findExplicitReferences(const Stmt *S,
868  llvm::function_ref<void(ReferenceLoc)> Out) {
869  assert(S);
870  ExplicitReferenceCollector(Out).TraverseStmt(const_cast<Stmt *>(S));
871 }
873  llvm::function_ref<void(ReferenceLoc)> Out) {
874  assert(D);
875  ExplicitReferenceCollector(Out).TraverseDecl(const_cast<Decl *>(D));
876 }
877 void findExplicitReferences(const ASTContext &AST,
878  llvm::function_ref<void(ReferenceLoc)> Out) {
879  ExplicitReferenceCollector(Out).TraverseAST(const_cast<ASTContext &>(AST));
880 }
881 
882 llvm::raw_ostream &operator<<(llvm::raw_ostream &OS, DeclRelation R) {
883  switch (R) {
884 #define REL_CASE(X) \
885  case DeclRelation::X: \
886  return OS << #X;
887  REL_CASE(Alias);
891 #undef REL_CASE
892  }
893  llvm_unreachable("Unhandled DeclRelation enum");
894 }
895 llvm::raw_ostream &operator<<(llvm::raw_ostream &OS, DeclRelationSet RS) {
896  const char *Sep = "";
897  for (unsigned I = 0; I < RS.S.size(); ++I) {
898  if (RS.S.test(I)) {
899  OS << Sep << static_cast<DeclRelation>(I);
900  Sep = "|";
901  }
902  }
903  return OS;
904 }
905 
906 llvm::raw_ostream &operator<<(llvm::raw_ostream &OS, ReferenceLoc R) {
907  // note we cannot print R.NameLoc without a source manager.
908  OS << "targets = {";
909  bool First = true;
910  for (const NamedDecl *T : R.Targets) {
911  if (!First)
912  OS << ", ";
913  else
914  First = false;
916  }
917  OS << "}";
918  if (R.Qualifier) {
919  OS << ", qualifier = '";
920  R.Qualifier.getNestedNameSpecifier()->print(OS,
921  PrintingPolicy(LangOptions()));
922  OS << "'";
923  }
924  if (R.IsDecl)
925  OS << ", decl";
926  return OS;
927 }
928 
929 } // namespace clangd
930 } // namespace clang
QualType DeducedType
Definition: AST.cpp:414
const FunctionDecl * Decl
std::string printQualifiedName(const NamedDecl &ND)
Returns the qualified name of ND.
Definition: AST.cpp:169
Information about a reference written in the source code, independent of the actual AST node that thi...
Definition: FindTarget.h:119
const Node * Parent
llvm::SmallVector< std::pair< const NamedDecl *, DeclRelationSet >, 1 > allTargetDecls(const ast_type_traits::DynTypedNode &N)
Similar to targetDecl(), however instead of applying a filter, all possible decls are returned along ...
Definition: FindTarget.cpp:486
This is the pattern the template specialization was instantiated from.
#define REL_CASE(X)
Represents a symbol occurrence in the source file.
Definition: Ref.h:52
std::vector< const char * > Flags
NestedNameSpecifierLoc getQualifierLoc(const NamedDecl &ND)
Returns a nested name specifier loc of ND if it was present in the source, e.g.
Definition: AST.cpp:188
std::string printTemplateSpecializationArgs(const NamedDecl &ND)
Prints template arguments of a decl as written in the source code, including enclosing &#39;<&#39; and &#39;>&#39;...
Definition: AST.cpp:249
static std::string replace(llvm::StringRef Haystack, llvm::StringRef Needle, llvm::StringRef Repl)
Definition: TestIndex.cpp:30
This declaration is an alias that was referred to.
Context Ctx
bool IsDecl
True if the reference is a declaration or definition;.
Definition: FindTarget.h:125
SourceLocation NameLoc
Start location of the last name part, i.e. &#39;foo&#39; in &#39;ns::foo<int>&#39;.
Definition: FindTarget.h:123
llvm::SmallVector< const NamedDecl *, 1 > explicitReferenceTargets(DynTypedNode N, DeclRelationSet Mask)
Definition: FindTarget.cpp:519
This is the template instantiation that was referred to.
#define dlog(...)
Definition: Logger.h:72
static constexpr llvm::StringLiteral Name
llvm::SmallVector< const NamedDecl *, 1 > Targets
A list of targets referenced by this name.
Definition: FindTarget.h:131
llvm::SmallVector< const NamedDecl *, 1 > targetDecl(const ast_type_traits::DynTypedNode &N, DeclRelationSet Mask)
targetDecl() finds the declaration referred to by an AST node.
Definition: FindTarget.cpp:509
===– Representation.cpp - ClangDoc Representation --------—*- C++ -*-===//
void findExplicitReferences(const Stmt *S, llvm::function_ref< void(ReferenceLoc)> Out)
Recursively traverse S and report all references explicitly written in the code.
Definition: FindTarget.cpp:867
This is the underlying declaration for an alias, decltype etc.
const Expr * E
RefSlab Refs
llvm::raw_ostream & operator<<(llvm::raw_ostream &OS, const CodeCompletion &C)
NestedNameSpecifierLoc Qualifier
Contains qualifier written in the code, if any, e.g. &#39;ns::&#39; for &#39;ns::foo&#39;.
Definition: FindTarget.h:121
NodeType Type