1//===------- QualTypeNames.cpp - Generate Complete QualType Names ---------===//
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 "clang/AST/DeclTemplate.h"
10#include "clang/AST/DeclarationName.h"
11#include "clang/AST/GlobalDecl.h"
12#include "clang/AST/Mangle.h"
13#include "clang/AST/QualTypeNames.h"
14
15#include <stdio.h>
16#include <memory>
17
18namespace clang {
19
20namespace TypeName {
21
22/// Create a NestedNameSpecifier for Namesp and its enclosing
23/// scopes.
24///
25/// \param[in] Ctx - the AST Context to be used.
26/// \param[in] Namesp - the NamespaceDecl for which a NestedNameSpecifier
27/// is requested.
28/// \param[in] WithGlobalNsPrefix - Indicate whether the global namespace
29/// specifier "::" should be prepended or not.
30static NestedNameSpecifier *createNestedNameSpecifier(
31    const ASTContext &Ctx,
32    const NamespaceDecl *Namesp,
33    bool WithGlobalNsPrefix);
34
35/// Create a NestedNameSpecifier for TagDecl and its enclosing
36/// scopes.
37///
38/// \param[in] Ctx - the AST Context to be used.
39/// \param[in] TD - the TagDecl for which a NestedNameSpecifier is
40/// requested.
41/// \param[in] FullyQualify - Convert all template arguments into fully
42/// qualified names.
43/// \param[in] WithGlobalNsPrefix - Indicate whether the global namespace
44/// specifier "::" should be prepended or not.
45static NestedNameSpecifier *createNestedNameSpecifier(
46    const ASTContext &Ctx, const TypeDecl *TD,
47    bool FullyQualify, bool WithGlobalNsPrefix);
48
49static NestedNameSpecifier *createNestedNameSpecifierForScopeOf(
50    const ASTContext &Ctx, const Decl *decl,
51    bool FullyQualified, bool WithGlobalNsPrefix);
52
53static NestedNameSpecifier *getFullyQualifiedNestedNameSpecifier(
54    const ASTContext &Ctx, NestedNameSpecifier *scope, bool WithGlobalNsPrefix);
55
56static bool getFullyQualifiedTemplateName(const ASTContext &Ctx,
57                                          TemplateName &TName,
58                                          bool WithGlobalNsPrefix) {
59  bool Changed = false;
60  NestedNameSpecifier *NNS = nullptr;
61
62  TemplateDecl *ArgTDecl = TName.getAsTemplateDecl();
63  // ArgTDecl won't be NULL because we asserted that this isn't a
64  // dependent context very early in the call chain.
65  assert(ArgTDecl != nullptr);
66  QualifiedTemplateName *QTName = TName.getAsQualifiedTemplateName();
67
68  if (QTName && !QTName->hasTemplateKeyword()) {
69    NNS = QTName->getQualifier();
70    NestedNameSpecifier *QNNS = getFullyQualifiedNestedNameSpecifier(
71        Ctx, NNS, WithGlobalNsPrefix);
72    if (QNNS != NNS) {
73      Changed = true;
74      NNS = QNNS;
75    } else {
76      NNS = nullptr;
77    }
78  } else {
79    NNS = createNestedNameSpecifierForScopeOf(
80        Ctx, ArgTDecl, true, WithGlobalNsPrefix);
81  }
82  if (NNS) {
83    TemplateName UnderlyingTN(ArgTDecl);
84    if (UsingShadowDecl *USD = TName.getAsUsingShadowDecl())
85      UnderlyingTN = TemplateName(USD);
86    TName =
87        Ctx.getQualifiedTemplateName(NNS,
88                                     /*TemplateKeyword=*/false, UnderlyingTN);
89    Changed = true;
90  }
91  return Changed;
92}
93
94static bool getFullyQualifiedTemplateArgument(const ASTContext &Ctx,
95                                              TemplateArgument &Arg,
96                                              bool WithGlobalNsPrefix) {
97  bool Changed = false;
98
99  // Note: we do not handle TemplateArgument::Expression, to replace it
100  // we need the information for the template instance decl.
101
102  if (Arg.getKind() == TemplateArgument::Template) {
103    TemplateName TName = Arg.getAsTemplate();
104    Changed = getFullyQualifiedTemplateName(Ctx, TName, WithGlobalNsPrefix);
105    if (Changed) {
106      Arg = TemplateArgument(TName);
107    }
108  } else if (Arg.getKind() == TemplateArgument::Type) {
109    QualType SubTy = Arg.getAsType();
110    // Check if the type needs more desugaring and recurse.
111    QualType QTFQ = getFullyQualifiedType(SubTy, Ctx, WithGlobalNsPrefix);
112    if (QTFQ != SubTy) {
113      Arg = TemplateArgument(QTFQ);
114      Changed = true;
115    }
116  }
117  return Changed;
118}
119
120static const Type *getFullyQualifiedTemplateType(const ASTContext &Ctx,
121                                                 const Type *TypePtr,
122                                                 bool WithGlobalNsPrefix) {
123  // DependentTemplateTypes exist within template declarations and
124  // definitions. Therefore we shouldn't encounter them at the end of
125  // a translation unit. If we do, the caller has made an error.
126  assert(!isa<DependentTemplateSpecializationType>(TypePtr));
127  // In case of template specializations, iterate over the arguments
128  // and fully qualify them as well.
129  if (const auto *TST = dyn_cast<const TemplateSpecializationType>(TypePtr)) {
130    bool MightHaveChanged = false;
131    SmallVector<TemplateArgument, 4> FQArgs;
132    // Cheap to copy and potentially modified by
133    // getFullyQualifedTemplateArgument.
134    for (TemplateArgument Arg : TST->template_arguments()) {
135      MightHaveChanged |= getFullyQualifiedTemplateArgument(
136          Ctx, Arg, WithGlobalNsPrefix);
137      FQArgs.push_back(Arg);
138    }
139
140    // If a fully qualified arg is different from the unqualified arg,
141    // allocate new type in the AST.
142    if (MightHaveChanged) {
143      QualType QT = Ctx.getTemplateSpecializationType(
144          TST->getTemplateName(), FQArgs,
145          TST->getCanonicalTypeInternal());
146      // getTemplateSpecializationType returns a fully qualified
147      // version of the specialization itself, so no need to qualify
148      // it.
149      return QT.getTypePtr();
150    }
151  } else if (const auto *TSTRecord = dyn_cast<const RecordType>(TypePtr)) {
152    // We are asked to fully qualify and we have a Record Type,
153    // which can point to a template instantiation with no sugar in any of
154    // its template argument, however we still need to fully qualify them.
155
156    if (const auto *TSTDecl =
157        dyn_cast<ClassTemplateSpecializationDecl>(TSTRecord->getDecl())) {
158      const TemplateArgumentList &TemplateArgs = TSTDecl->getTemplateArgs();
159
160      bool MightHaveChanged = false;
161      SmallVector<TemplateArgument, 4> FQArgs;
162      for (unsigned int I = 0, E = TemplateArgs.size(); I != E; ++I) {
163        // cheap to copy and potentially modified by
164        // getFullyQualifedTemplateArgument
165        TemplateArgument Arg(TemplateArgs[I]);
166        MightHaveChanged |= getFullyQualifiedTemplateArgument(
167            Ctx, Arg, WithGlobalNsPrefix);
168        FQArgs.push_back(Arg);
169      }
170
171      // If a fully qualified arg is different from the unqualified arg,
172      // allocate new type in the AST.
173      if (MightHaveChanged) {
174        TemplateName TN(TSTDecl->getSpecializedTemplate());
175        QualType QT = Ctx.getTemplateSpecializationType(
176            TN, FQArgs,
177            TSTRecord->getCanonicalTypeInternal());
178        // getTemplateSpecializationType returns a fully qualified
179        // version of the specialization itself, so no need to qualify
180        // it.
181        return QT.getTypePtr();
182      }
183    }
184  }
185  return TypePtr;
186}
187
188static NestedNameSpecifier *createOuterNNS(const ASTContext &Ctx, const Decl *D,
189                                           bool FullyQualify,
190                                           bool WithGlobalNsPrefix) {
191  const DeclContext *DC = D->getDeclContext();
192  if (const auto *NS = dyn_cast<NamespaceDecl>(DC)) {
193    while (NS && NS->isInline()) {
194      // Ignore inline namespace;
195      NS = dyn_cast<NamespaceDecl>(NS->getDeclContext());
196    }
197    if (NS && NS->getDeclName()) {
198      return createNestedNameSpecifier(Ctx, NS, WithGlobalNsPrefix);
199    }
200    return nullptr;  // no starting '::', no anonymous
201  } else if (const auto *TD = dyn_cast<TagDecl>(DC)) {
202    return createNestedNameSpecifier(Ctx, TD, FullyQualify, WithGlobalNsPrefix);
203  } else if (const auto *TDD = dyn_cast<TypedefNameDecl>(DC)) {
204    return createNestedNameSpecifier(
205        Ctx, TDD, FullyQualify, WithGlobalNsPrefix);
206  } else if (WithGlobalNsPrefix && DC->isTranslationUnit()) {
207    return NestedNameSpecifier::GlobalSpecifier(Ctx);
208  }
209  return nullptr;  // no starting '::' if |WithGlobalNsPrefix| is false
210}
211
212/// Return a fully qualified version of this name specifier.
213static NestedNameSpecifier *getFullyQualifiedNestedNameSpecifier(
214    const ASTContext &Ctx, NestedNameSpecifier *Scope,
215    bool WithGlobalNsPrefix) {
216  switch (Scope->getKind()) {
217    case NestedNameSpecifier::Global:
218      // Already fully qualified
219      return Scope;
220    case NestedNameSpecifier::Namespace:
221      return TypeName::createNestedNameSpecifier(
222          Ctx, Scope->getAsNamespace(), WithGlobalNsPrefix);
223    case NestedNameSpecifier::NamespaceAlias:
224      // Namespace aliases are only valid for the duration of the
225      // scope where they were introduced, and therefore are often
226      // invalid at the end of the TU.  So use the namespace name more
227      // likely to be valid at the end of the TU.
228      return TypeName::createNestedNameSpecifier(
229          Ctx,
230          Scope->getAsNamespaceAlias()->getNamespace()->getCanonicalDecl(),
231          WithGlobalNsPrefix);
232    case NestedNameSpecifier::Identifier:
233      // A function or some other construct that makes it un-namable
234      // at the end of the TU. Skip the current component of the name,
235      // but use the name of it's prefix.
236      return getFullyQualifiedNestedNameSpecifier(
237          Ctx, Scope->getPrefix(), WithGlobalNsPrefix);
238    case NestedNameSpecifier::Super:
239    case NestedNameSpecifier::TypeSpec:
240    case NestedNameSpecifier::TypeSpecWithTemplate: {
241      const Type *Type = Scope->getAsType();
242      // Find decl context.
243      const TagDecl *TD = nullptr;
244      if (const TagType *TagDeclType = Type->getAs<TagType>()) {
245        TD = TagDeclType->getDecl();
246      } else {
247        TD = Type->getAsCXXRecordDecl();
248      }
249      if (TD) {
250        return TypeName::createNestedNameSpecifier(Ctx, TD,
251                                                   true /*FullyQualified*/,
252                                                   WithGlobalNsPrefix);
253      } else if (const auto *TDD = dyn_cast<TypedefType>(Type)) {
254        return TypeName::createNestedNameSpecifier(Ctx, TDD->getDecl(),
255                                                   true /*FullyQualified*/,
256                                                   WithGlobalNsPrefix);
257      }
258      return Scope;
259    }
260  }
261  llvm_unreachable("bad NNS kind");
262}
263
264/// Create a nested name specifier for the declaring context of
265/// the type.
266static NestedNameSpecifier *createNestedNameSpecifierForScopeOf(
267    const ASTContext &Ctx, const Decl *Decl,
268    bool FullyQualified, bool WithGlobalNsPrefix) {
269  assert(Decl);
270
271  const DeclContext *DC = Decl->getDeclContext()->getRedeclContext();
272  const auto *Outer = dyn_cast_or_null<NamedDecl>(DC);
273  const auto *OuterNS = dyn_cast_or_null<NamespaceDecl>(DC);
274  if (Outer && !(OuterNS && OuterNS->isAnonymousNamespace())) {
275    if (const auto *CxxDecl = dyn_cast<CXXRecordDecl>(DC)) {
276      if (ClassTemplateDecl *ClassTempl =
277              CxxDecl->getDescribedClassTemplate()) {
278        // We are in the case of a type(def) that was declared in a
279        // class template but is *not* type dependent.  In clang, it
280        // gets attached to the class template declaration rather than
281        // any specific class template instantiation.  This result in
282        // 'odd' fully qualified typename:
283        //
284        //    vector<_Tp,_Alloc>::size_type
285        //
286        // Make the situation is 'useable' but looking a bit odd by
287        // picking a random instance as the declaring context.
288        if (ClassTempl->spec_begin() != ClassTempl->spec_end()) {
289          Decl = *(ClassTempl->spec_begin());
290          Outer = dyn_cast<NamedDecl>(Decl);
291          OuterNS = dyn_cast<NamespaceDecl>(Decl);
292        }
293      }
294    }
295
296    if (OuterNS) {
297      return createNestedNameSpecifier(Ctx, OuterNS, WithGlobalNsPrefix);
298    } else if (const auto *TD = dyn_cast<TagDecl>(Outer)) {
299      return createNestedNameSpecifier(
300          Ctx, TD, FullyQualified, WithGlobalNsPrefix);
301    } else if (isa<TranslationUnitDecl>(Outer)) {
302      // Context is the TU. Nothing needs to be done.
303      return nullptr;
304    } else {
305      // Decl's context was neither the TU, a namespace, nor a
306      // TagDecl, which means it is a type local to a scope, and not
307      // accessible at the end of the TU.
308      return nullptr;
309    }
310  } else if (WithGlobalNsPrefix && DC->isTranslationUnit()) {
311    return NestedNameSpecifier::GlobalSpecifier(Ctx);
312  }
313  return nullptr;
314}
315
316/// Create a nested name specifier for the declaring context of
317/// the type.
318static NestedNameSpecifier *createNestedNameSpecifierForScopeOf(
319    const ASTContext &Ctx, const Type *TypePtr,
320    bool FullyQualified, bool WithGlobalNsPrefix) {
321  if (!TypePtr) return nullptr;
322
323  Decl *Decl = nullptr;
324  // There are probably other cases ...
325  if (const auto *TDT = dyn_cast<TypedefType>(TypePtr)) {
326    Decl = TDT->getDecl();
327  } else if (const auto *TagDeclType = dyn_cast<TagType>(TypePtr)) {
328    Decl = TagDeclType->getDecl();
329  } else if (const auto *TST = dyn_cast<TemplateSpecializationType>(TypePtr)) {
330    Decl = TST->getTemplateName().getAsTemplateDecl();
331  } else {
332    Decl = TypePtr->getAsCXXRecordDecl();
333  }
334
335  if (!Decl) return nullptr;
336
337  return createNestedNameSpecifierForScopeOf(
338      Ctx, Decl, FullyQualified, WithGlobalNsPrefix);
339}
340
341NestedNameSpecifier *createNestedNameSpecifier(const ASTContext &Ctx,
342                                               const NamespaceDecl *Namespace,
343                                               bool WithGlobalNsPrefix) {
344  while (Namespace && Namespace->isInline()) {
345    // Ignore inline namespace;
346    Namespace = dyn_cast<NamespaceDecl>(Namespace->getDeclContext());
347  }
348  if (!Namespace) return nullptr;
349
350  bool FullyQualified = true;  // doesn't matter, DeclContexts are namespaces
351  return NestedNameSpecifier::Create(
352      Ctx,
353      createOuterNNS(Ctx, Namespace, FullyQualified, WithGlobalNsPrefix),
354      Namespace);
355}
356
357NestedNameSpecifier *createNestedNameSpecifier(const ASTContext &Ctx,
358                                               const TypeDecl *TD,
359                                               bool FullyQualify,
360                                               bool WithGlobalNsPrefix) {
361  const Type *TypePtr = TD->getTypeForDecl();
362  if (isa<const TemplateSpecializationType>(TypePtr) ||
363      isa<const RecordType>(TypePtr)) {
364    // We are asked to fully qualify and we have a Record Type (which
365    // may point to a template specialization) or Template
366    // Specialization Type. We need to fully qualify their arguments.
367
368    TypePtr = getFullyQualifiedTemplateType(Ctx, TypePtr, WithGlobalNsPrefix);
369  }
370
371  return NestedNameSpecifier::Create(
372      Ctx, createOuterNNS(Ctx, TD, FullyQualify, WithGlobalNsPrefix),
373      false /*No TemplateKeyword*/, TypePtr);
374}
375
376/// Return the fully qualified type, including fully-qualified
377/// versions of any template parameters.
378QualType getFullyQualifiedType(QualType QT, const ASTContext &Ctx,
379                               bool WithGlobalNsPrefix) {
380  // In case of myType* we need to strip the pointer first, fully
381  // qualify and attach the pointer once again.
382  if (isa<PointerType>(QT.getTypePtr())) {
383    // Get the qualifiers.
384    Qualifiers Quals = QT.getQualifiers();
385    QT = getFullyQualifiedType(QT->getPointeeType(), Ctx, WithGlobalNsPrefix);
386    QT = Ctx.getPointerType(QT);
387    // Add back the qualifiers.
388    QT = Ctx.getQualifiedType(QT, Quals);
389    return QT;
390  }
391
392  if (auto *MPT = dyn_cast<MemberPointerType>(QT.getTypePtr())) {
393    // Get the qualifiers.
394    Qualifiers Quals = QT.getQualifiers();
395    // Fully qualify the pointee and class types.
396    QT = getFullyQualifiedType(QT->getPointeeType(), Ctx, WithGlobalNsPrefix);
397    QualType Class = getFullyQualifiedType(QualType(MPT->getClass(), 0), Ctx,
398                                           WithGlobalNsPrefix);
399    QT = Ctx.getMemberPointerType(QT, Class.getTypePtr());
400    // Add back the qualifiers.
401    QT = Ctx.getQualifiedType(QT, Quals);
402    return QT;
403  }
404
405  // In case of myType& we need to strip the reference first, fully
406  // qualify and attach the reference once again.
407  if (isa<ReferenceType>(QT.getTypePtr())) {
408    // Get the qualifiers.
409    bool IsLValueRefTy = isa<LValueReferenceType>(QT.getTypePtr());
410    Qualifiers Quals = QT.getQualifiers();
411    QT = getFullyQualifiedType(QT->getPointeeType(), Ctx, WithGlobalNsPrefix);
412    // Add the r- or l-value reference type back to the fully
413    // qualified one.
414    if (IsLValueRefTy)
415      QT = Ctx.getLValueReferenceType(QT);
416    else
417      QT = Ctx.getRValueReferenceType(QT);
418    // Add back the qualifiers.
419    QT = Ctx.getQualifiedType(QT, Quals);
420    return QT;
421  }
422
423  // Remove the part of the type related to the type being a template
424  // parameter (we won't report it as part of the 'type name' and it
425  // is actually make the code below to be more complex (to handle
426  // those)
427  while (isa<SubstTemplateTypeParmType>(QT.getTypePtr())) {
428    // Get the qualifiers.
429    Qualifiers Quals = QT.getQualifiers();
430
431    QT = cast<SubstTemplateTypeParmType>(QT.getTypePtr())->desugar();
432
433    // Add back the qualifiers.
434    QT = Ctx.getQualifiedType(QT, Quals);
435  }
436
437  NestedNameSpecifier *Prefix = nullptr;
438  // Local qualifiers are attached to the QualType outside of the
439  // elaborated type.  Retrieve them before descending into the
440  // elaborated type.
441  Qualifiers PrefixQualifiers = QT.getLocalQualifiers();
442  QT = QualType(QT.getTypePtr(), 0);
443  ElaboratedTypeKeyword Keyword = ElaboratedTypeKeyword::None;
444  if (const auto *ETypeInput = dyn_cast<ElaboratedType>(QT.getTypePtr())) {
445    QT = ETypeInput->getNamedType();
446    assert(!QT.hasLocalQualifiers());
447    Keyword = ETypeInput->getKeyword();
448  }
449
450  // We don't consider the alias introduced by `using a::X` as a new type.
451  // The qualified name is still a::X.
452  if (const auto *UT = QT->getAs<UsingType>()) {
453    QT = Ctx.getQualifiedType(UT->getUnderlyingType(), PrefixQualifiers);
454    return getFullyQualifiedType(QT, Ctx, WithGlobalNsPrefix);
455  }
456
457  // Create a nested name specifier if needed.
458  Prefix = createNestedNameSpecifierForScopeOf(Ctx, QT.getTypePtr(),
459                                               true /*FullyQualified*/,
460                                               WithGlobalNsPrefix);
461
462  // In case of template specializations iterate over the arguments and
463  // fully qualify them as well.
464  if (isa<const TemplateSpecializationType>(QT.getTypePtr()) ||
465      isa<const RecordType>(QT.getTypePtr())) {
466    // We are asked to fully qualify and we have a Record Type (which
467    // may point to a template specialization) or Template
468    // Specialization Type. We need to fully qualify their arguments.
469
470    const Type *TypePtr = getFullyQualifiedTemplateType(
471        Ctx, QT.getTypePtr(), WithGlobalNsPrefix);
472    QT = QualType(TypePtr, 0);
473  }
474  if (Prefix || Keyword != ElaboratedTypeKeyword::None) {
475    QT = Ctx.getElaboratedType(Keyword, Prefix, QT);
476  }
477  QT = Ctx.getQualifiedType(QT, PrefixQualifiers);
478  return QT;
479}
480
481std::string getFullyQualifiedName(QualType QT,
482                                  const ASTContext &Ctx,
483                                  const PrintingPolicy &Policy,
484                                  bool WithGlobalNsPrefix) {
485  QualType FQQT = getFullyQualifiedType(QT, Ctx, WithGlobalNsPrefix);
486  return FQQT.getAsString(Policy);
487}
488
489}  // end namespace TypeName
490}  // end namespace clang
491