TemplateBase.h revision d7a6b1640e565487d163023a6a2e83f55476ae96 
1//===-- TemplateBase.h - Core classes for C++ templates ---------*- C++ -*-===//
2//
3//                     The LLVM Compiler Infrastructure
4//
5// This file is distributed under the University of Illinois Open Source
6// License. See LICENSE.TXT for details.
7//
8//===----------------------------------------------------------------------===//
9//
10//  This file provides definitions which are common for all kinds of
11//  template representation.
12//
13//===----------------------------------------------------------------------===//
14
15#ifndef LLVM_CLANG_AST_TEMPLATEBASE_H
16#define LLVM_CLANG_AST_TEMPLATEBASE_H
17
18#include "clang/AST/Type.h"
19#include "clang/AST/TemplateName.h"
20#include "llvm/ADT/APSInt.h"
21#include "llvm/ADT/SmallVector.h"
22#include "llvm/Support/Compiler.h"
23#include "llvm/Support/ErrorHandling.h"
24
25namespace llvm {
26  class FoldingSetNodeID;
27}
28
29namespace clang {
30
31class DiagnosticBuilder;
32class Expr;
33struct PrintingPolicy;
34class TypeSourceInfo;
35class ValueDecl;
36
37/// \brief Represents a template argument within a class template
38/// specialization.
39class TemplateArgument {
40public:
41  /// \brief The kind of template argument we're storing.
42  enum ArgKind {
43    /// \brief Represents an empty template argument, e.g., one that has not
44    /// been deduced.
45    Null = 0,
46    /// The template argument is a type.
47    Type,
48    /// The template argument is a declaration that was provided for a pointer,
49    /// reference, or pointer to member non-type template parameter.
50    Declaration,
51    /// The template argument is a null pointer or null pointer to member that
52    /// was provided for a non-type template parameter.
53    NullPtr,
54    /// The template argument is an integral value stored in an llvm::APSInt
55    /// that was provided for an integral non-type template parameter.
56    Integral,
57    /// The template argument is a template name that was provided for a
58    /// template template parameter.
59    Template,
60    /// The template argument is a pack expansion of a template name that was
61    /// provided for a template template parameter.
62    TemplateExpansion,
63    /// The template argument is a value- or type-dependent expression
64    /// stored in an Expr*.
65    Expression,
66    /// The template argument is actually a parameter pack. Arguments are stored
67    /// in the Args struct.
68    Pack
69  };
70
71private:
72  /// \brief The kind of template argument we're storing.
73  unsigned Kind;
74
75  union {
76    uintptr_t TypeOrValue;
77    struct {
78      ValueDecl *D;
79      bool ForRefParam;
80    } DeclArg;
81    struct {
82      // We store a decomposed APSInt with the data allocated by ASTContext if
83      // BitWidth > 64. The memory may be shared between multiple
84      // TemplateArgument instances.
85      union {
86        uint64_t VAL;          ///< Used to store the <= 64 bits integer value.
87        const uint64_t *pVal;  ///< Used to store the >64 bits integer value.
88      };
89      unsigned BitWidth : 31;
90      unsigned IsUnsigned : 1;
91      void *Type;
92    } Integer;
93    struct {
94      const TemplateArgument *Args;
95      unsigned NumArgs;
96    } Args;
97    struct {
98      void *Name;
99      unsigned NumExpansions;
100    } TemplateArg;
101  };
102
103  TemplateArgument(TemplateName, bool); // DO NOT USE
104
105public:
106  /// \brief Construct an empty, invalid template argument.
107  TemplateArgument() : Kind(Null), TypeOrValue(0) { }
108
109  /// \brief Construct a template type argument.
110  TemplateArgument(QualType T, bool isNullPtr = false)
111    : Kind(isNullPtr ? NullPtr : Type) {
112    TypeOrValue = reinterpret_cast<uintptr_t>(T.getAsOpaquePtr());
113  }
114
115  /// \brief Construct a template argument that refers to a
116  /// declaration, which is either an external declaration or a
117  /// template declaration.
118  TemplateArgument(ValueDecl *D, bool ForRefParam) : Kind(Declaration) {
119    assert(D && "Expected decl");
120    DeclArg.D = D;
121    DeclArg.ForRefParam = ForRefParam;
122  }
123
124  /// \brief Construct an integral constant template argument. The memory to
125  /// store the value is allocated with Ctx.
126  TemplateArgument(ASTContext &Ctx, const llvm::APSInt &Value, QualType Type);
127
128  /// \brief Construct an integral constant template argument with the same
129  /// value as Other but a different type.
130  TemplateArgument(const TemplateArgument &Other, QualType Type)
131    : Kind(Integral) {
132    Integer = Other.Integer;
133    Integer.Type = Type.getAsOpaquePtr();
134  }
135
136  /// \brief Construct a template argument that is a template.
137  ///
138  /// This form of template argument is generally used for template template
139  /// parameters. However, the template name could be a dependent template
140  /// name that ends up being instantiated to a function template whose address
141  /// is taken.
142  ///
143  /// \param Name The template name.
144  TemplateArgument(TemplateName Name) : Kind(Template)
145  {
146    TemplateArg.Name = Name.getAsVoidPointer();
147    TemplateArg.NumExpansions = 0;
148  }
149
150  /// \brief Construct a template argument that is a template pack expansion.
151  ///
152  /// This form of template argument is generally used for template template
153  /// parameters. However, the template name could be a dependent template
154  /// name that ends up being instantiated to a function template whose address
155  /// is taken.
156  ///
157  /// \param Name The template name.
158  ///
159  /// \param NumExpansions The number of expansions that will be generated by
160  /// instantiating
161  TemplateArgument(TemplateName Name, llvm::Optional<unsigned> NumExpansions)
162    : Kind(TemplateExpansion)
163  {
164    TemplateArg.Name = Name.getAsVoidPointer();
165    if (NumExpansions)
166      TemplateArg.NumExpansions = *NumExpansions + 1;
167    else
168      TemplateArg.NumExpansions = 0;
169  }
170
171  /// \brief Construct a template argument that is an expression.
172  ///
173  /// This form of template argument only occurs in template argument
174  /// lists used for dependent types and for expression; it will not
175  /// occur in a non-dependent, canonical template argument list.
176  TemplateArgument(Expr *E) : Kind(Expression) {
177    TypeOrValue = reinterpret_cast<uintptr_t>(E);
178  }
179
180  /// \brief Construct a template argument that is a template argument pack.
181  ///
182  /// We assume that storage for the template arguments provided
183  /// outlives the TemplateArgument itself.
184  TemplateArgument(const TemplateArgument *Args, unsigned NumArgs) : Kind(Pack){
185    this->Args.Args = Args;
186    this->Args.NumArgs = NumArgs;
187  }
188
189  static TemplateArgument getEmptyPack() {
190    return TemplateArgument((TemplateArgument*)0, 0);
191  }
192
193  /// \brief Create a new template argument pack by copying the given set of
194  /// template arguments.
195  static TemplateArgument CreatePackCopy(ASTContext &Context,
196                                         const TemplateArgument *Args,
197                                         unsigned NumArgs);
198
199  /// \brief Return the kind of stored template argument.
200  ArgKind getKind() const { return (ArgKind)Kind; }
201
202  /// \brief Determine whether this template argument has no value.
203  bool isNull() const { return Kind == Null; }
204
205  /// \brief Whether this template argument is dependent on a template
206  /// parameter such that its result can change from one instantiation to
207  /// another.
208  bool isDependent() const;
209
210  /// \brief Whether this template argument is dependent on a template
211  /// parameter.
212  bool isInstantiationDependent() const;
213
214  /// \brief Whether this template argument contains an unexpanded
215  /// parameter pack.
216  bool containsUnexpandedParameterPack() const;
217
218  /// \brief Determine whether this template argument is a pack expansion.
219  bool isPackExpansion() const;
220
221  /// \brief Retrieve the type for a type template argument.
222  QualType getAsType() const {
223    assert(Kind == Type && "Unexpected kind");
224    return QualType::getFromOpaquePtr(reinterpret_cast<void*>(TypeOrValue));
225  }
226
227  /// \brief Retrieve the declaration for a declaration non-type
228  /// template argument.
229  ValueDecl *getAsDecl() const {
230    assert(Kind == Declaration && "Unexpected kind");
231    return DeclArg.D;
232  }
233
234  /// \brief Retrieve whether a declaration is binding to a
235  /// reference parameter in a declaration non-type template argument.
236  bool isDeclForReferenceParam() const {
237    assert(Kind == Declaration && "Unexpected kind");
238    return DeclArg.ForRefParam;
239  }
240
241  /// \brief Retrieve the type for null non-type template argument.
242  QualType getNullPtrType() const {
243    assert(Kind == NullPtr && "Unexpected kind");
244    return QualType::getFromOpaquePtr(reinterpret_cast<void*>(TypeOrValue));
245  }
246
247  /// \brief Retrieve the template name for a template name argument.
248  TemplateName getAsTemplate() const {
249    assert(Kind == Template && "Unexpected kind");
250    return TemplateName::getFromVoidPointer(TemplateArg.Name);
251  }
252
253  /// \brief Retrieve the template argument as a template name; if the argument
254  /// is a pack expansion, return the pattern as a template name.
255  TemplateName getAsTemplateOrTemplatePattern() const {
256    assert((Kind == Template || Kind == TemplateExpansion) &&
257           "Unexpected kind");
258
259    return TemplateName::getFromVoidPointer(TemplateArg.Name);
260  }
261
262  /// \brief Retrieve the number of expansions that a template template argument
263  /// expansion will produce, if known.
264  llvm::Optional<unsigned> getNumTemplateExpansions() const;
265
266  /// \brief Retrieve the template argument as an integral value.
267  // FIXME: Provide a way to read the integral data without copying the value.
268  llvm::APSInt getAsIntegral() const {
269    assert(Kind == Integral && "Unexpected kind");
270    using namespace llvm;
271    if (Integer.BitWidth <= 64)
272      return APSInt(APInt(Integer.BitWidth, Integer.VAL), Integer.IsUnsigned);
273
274    unsigned NumWords = APInt::getNumWords(Integer.BitWidth);
275    return APSInt(APInt(Integer.BitWidth, makeArrayRef(Integer.pVal, NumWords)),
276                  Integer.IsUnsigned);
277  }
278
279  /// \brief Retrieve the type of the integral value.
280  QualType getIntegralType() const {
281    assert(Kind == Integral && "Unexpected kind");
282    return QualType::getFromOpaquePtr(Integer.Type);
283  }
284
285  void setIntegralType(QualType T) {
286    assert(Kind == Integral && "Unexpected kind");
287    Integer.Type = T.getAsOpaquePtr();
288  }
289
290  /// \brief Retrieve the template argument as an expression.
291  Expr *getAsExpr() const {
292    assert(Kind == Expression && "Unexpected kind");
293    return reinterpret_cast<Expr *>(TypeOrValue);
294  }
295
296  /// \brief Iterator that traverses the elements of a template argument pack.
297  typedef const TemplateArgument * pack_iterator;
298
299  /// \brief Iterator referencing the first argument of a template argument
300  /// pack.
301  pack_iterator pack_begin() const {
302    assert(Kind == Pack);
303    return Args.Args;
304  }
305
306  /// \brief Iterator referencing one past the last argument of a template
307  /// argument pack.
308  pack_iterator pack_end() const {
309    assert(Kind == Pack);
310    return Args.Args + Args.NumArgs;
311  }
312
313  /// \brief The number of template arguments in the given template argument
314  /// pack.
315  unsigned pack_size() const {
316    assert(Kind == Pack);
317    return Args.NumArgs;
318  }
319
320  /// \brief Determines whether two template arguments are superficially the
321  /// same.
322  bool structurallyEquals(const TemplateArgument &Other) const;
323
324  /// \brief When the template argument is a pack expansion, returns
325  /// the pattern of the pack expansion.
326  TemplateArgument getPackExpansionPattern() const;
327
328  /// \brief Print this template argument to the given output stream.
329  void print(const PrintingPolicy &Policy, raw_ostream &Out) const;
330
331  /// \brief Used to insert TemplateArguments into FoldingSets.
332  void Profile(llvm::FoldingSetNodeID &ID, const ASTContext &Context) const;
333};
334
335/// Location information for a TemplateArgument.
336struct TemplateArgumentLocInfo {
337private:
338  union {
339    Expr *Expression;
340    TypeSourceInfo *Declarator;
341    struct {
342      // FIXME: We'd like to just use the qualifier in the TemplateName,
343      // but template arguments get canonicalized too quickly.
344      NestedNameSpecifier *Qualifier;
345      void *QualifierLocData;
346      unsigned TemplateNameLoc;
347      unsigned EllipsisLoc;
348    } Template;
349  };
350
351public:
352  TemplateArgumentLocInfo();
353
354  TemplateArgumentLocInfo(TypeSourceInfo *TInfo) : Declarator(TInfo) {}
355
356  TemplateArgumentLocInfo(Expr *E) : Expression(E) {}
357
358  TemplateArgumentLocInfo(NestedNameSpecifierLoc QualifierLoc,
359                          SourceLocation TemplateNameLoc,
360                          SourceLocation EllipsisLoc)
361  {
362    Template.Qualifier = QualifierLoc.getNestedNameSpecifier();
363    Template.QualifierLocData = QualifierLoc.getOpaqueData();
364    Template.TemplateNameLoc = TemplateNameLoc.getRawEncoding();
365    Template.EllipsisLoc = EllipsisLoc.getRawEncoding();
366  }
367
368  TypeSourceInfo *getAsTypeSourceInfo() const {
369    return Declarator;
370  }
371
372  Expr *getAsExpr() const {
373    return Expression;
374  }
375
376  NestedNameSpecifierLoc getTemplateQualifierLoc() const {
377    return NestedNameSpecifierLoc(Template.Qualifier,
378                                  Template.QualifierLocData);
379  }
380
381  SourceLocation getTemplateNameLoc() const {
382    return SourceLocation::getFromRawEncoding(Template.TemplateNameLoc);
383  }
384
385  SourceLocation getTemplateEllipsisLoc() const {
386    return SourceLocation::getFromRawEncoding(Template.EllipsisLoc);
387  }
388};
389
390/// Location wrapper for a TemplateArgument.  TemplateArgument is to
391/// TemplateArgumentLoc as Type is to TypeLoc.
392class TemplateArgumentLoc {
393  TemplateArgument Argument;
394  TemplateArgumentLocInfo LocInfo;
395
396public:
397  TemplateArgumentLoc() {}
398
399  TemplateArgumentLoc(const TemplateArgument &Argument,
400                      TemplateArgumentLocInfo Opaque)
401    : Argument(Argument), LocInfo(Opaque) {
402  }
403
404  TemplateArgumentLoc(const TemplateArgument &Argument, TypeSourceInfo *TInfo)
405    : Argument(Argument), LocInfo(TInfo) {
406    assert(Argument.getKind() == TemplateArgument::Type);
407  }
408
409  TemplateArgumentLoc(const TemplateArgument &Argument, Expr *E)
410    : Argument(Argument), LocInfo(E) {
411    assert(Argument.getKind() == TemplateArgument::Expression);
412  }
413
414  TemplateArgumentLoc(const TemplateArgument &Argument,
415                      NestedNameSpecifierLoc QualifierLoc,
416                      SourceLocation TemplateNameLoc,
417                      SourceLocation EllipsisLoc = SourceLocation())
418    : Argument(Argument), LocInfo(QualifierLoc, TemplateNameLoc, EllipsisLoc) {
419    assert(Argument.getKind() == TemplateArgument::Template ||
420           Argument.getKind() == TemplateArgument::TemplateExpansion);
421  }
422
423  /// \brief - Fetches the primary location of the argument.
424  SourceLocation getLocation() const {
425    if (Argument.getKind() == TemplateArgument::Template ||
426        Argument.getKind() == TemplateArgument::TemplateExpansion)
427      return getTemplateNameLoc();
428
429    return getSourceRange().getBegin();
430  }
431
432  /// \brief - Fetches the full source range of the argument.
433  SourceRange getSourceRange() const LLVM_READONLY;
434
435  const TemplateArgument &getArgument() const {
436    return Argument;
437  }
438
439  TemplateArgumentLocInfo getLocInfo() const {
440    return LocInfo;
441  }
442
443  TypeSourceInfo *getTypeSourceInfo() const {
444    assert(Argument.getKind() == TemplateArgument::Type);
445    return LocInfo.getAsTypeSourceInfo();
446  }
447
448  Expr *getSourceExpression() const {
449    assert(Argument.getKind() == TemplateArgument::Expression);
450    return LocInfo.getAsExpr();
451  }
452
453  Expr *getSourceDeclExpression() const {
454    assert(Argument.getKind() == TemplateArgument::Declaration);
455    return LocInfo.getAsExpr();
456  }
457
458  Expr *getSourceNullPtrExpression() const {
459    assert(Argument.getKind() == TemplateArgument::NullPtr);
460    return LocInfo.getAsExpr();
461  }
462
463  Expr *getSourceIntegralExpression() const {
464    assert(Argument.getKind() == TemplateArgument::Integral);
465    return LocInfo.getAsExpr();
466  }
467
468  NestedNameSpecifierLoc getTemplateQualifierLoc() const {
469    assert(Argument.getKind() == TemplateArgument::Template ||
470           Argument.getKind() == TemplateArgument::TemplateExpansion);
471    return LocInfo.getTemplateQualifierLoc();
472  }
473
474  SourceLocation getTemplateNameLoc() const {
475    assert(Argument.getKind() == TemplateArgument::Template ||
476           Argument.getKind() == TemplateArgument::TemplateExpansion);
477    return LocInfo.getTemplateNameLoc();
478  }
479
480  SourceLocation getTemplateEllipsisLoc() const {
481    assert(Argument.getKind() == TemplateArgument::TemplateExpansion);
482    return LocInfo.getTemplateEllipsisLoc();
483  }
484
485  /// \brief When the template argument is a pack expansion, returns
486  /// the pattern of the pack expansion.
487  ///
488  /// \param Ellipsis Will be set to the location of the ellipsis.
489  ///
490  /// \param NumExpansions Will be set to the number of expansions that will
491  /// be generated from this pack expansion, if known a priori.
492  TemplateArgumentLoc getPackExpansionPattern(SourceLocation &Ellipsis,
493                                        llvm::Optional<unsigned> &NumExpansions,
494                                              ASTContext &Context) const;
495};
496
497/// A convenient class for passing around template argument
498/// information.  Designed to be passed by reference.
499class TemplateArgumentListInfo {
500  SmallVector<TemplateArgumentLoc, 8> Arguments;
501  SourceLocation LAngleLoc;
502  SourceLocation RAngleLoc;
503
504  // This can leak if used in an AST node, use ASTTemplateArgumentListInfo
505  // instead.
506  void* operator new(size_t bytes, ASTContext& C);
507
508public:
509  TemplateArgumentListInfo() {}
510
511  TemplateArgumentListInfo(SourceLocation LAngleLoc,
512                           SourceLocation RAngleLoc)
513    : LAngleLoc(LAngleLoc), RAngleLoc(RAngleLoc) {}
514
515  SourceLocation getLAngleLoc() const { return LAngleLoc; }
516  SourceLocation getRAngleLoc() const { return RAngleLoc; }
517
518  void setLAngleLoc(SourceLocation Loc) { LAngleLoc = Loc; }
519  void setRAngleLoc(SourceLocation Loc) { RAngleLoc = Loc; }
520
521  unsigned size() const { return Arguments.size(); }
522
523  const TemplateArgumentLoc *getArgumentArray() const {
524    return Arguments.data();
525  }
526
527  const TemplateArgumentLoc &operator[](unsigned I) const {
528    return Arguments[I];
529  }
530
531  void addArgument(const TemplateArgumentLoc &Loc) {
532    Arguments.push_back(Loc);
533  }
534};
535
536/// \brief Represents an explicit template argument list in C++, e.g.,
537/// the "<int>" in "sort<int>".
538/// This is safe to be used inside an AST node, in contrast with
539/// TemplateArgumentListInfo.
540struct ASTTemplateArgumentListInfo {
541  /// \brief The source location of the left angle bracket ('<').
542  SourceLocation LAngleLoc;
543
544  /// \brief The source location of the right angle bracket ('>').
545  SourceLocation RAngleLoc;
546
547  union {
548    /// \brief The number of template arguments in TemplateArgs.
549    /// The actual template arguments (if any) are stored after the
550    /// ExplicitTemplateArgumentList structure.
551    unsigned NumTemplateArgs;
552
553    /// Force ASTTemplateArgumentListInfo to the right alignment
554    /// for the following array of TemplateArgumentLocs.
555    void *Aligner;
556  };
557
558  /// \brief Retrieve the template arguments
559  TemplateArgumentLoc *getTemplateArgs() {
560    return reinterpret_cast<TemplateArgumentLoc *> (this + 1);
561  }
562
563  /// \brief Retrieve the template arguments
564  const TemplateArgumentLoc *getTemplateArgs() const {
565    return reinterpret_cast<const TemplateArgumentLoc *> (this + 1);
566  }
567
568  const TemplateArgumentLoc &operator[](unsigned I) const {
569    return getTemplateArgs()[I];
570  }
571
572  static const ASTTemplateArgumentListInfo *Create(ASTContext &C,
573                                          const TemplateArgumentListInfo &List);
574
575  void initializeFrom(const TemplateArgumentListInfo &List);
576  void initializeFrom(const TemplateArgumentListInfo &List,
577                      bool &Dependent, bool &InstantiationDependent,
578                      bool &ContainsUnexpandedParameterPack);
579  void copyInto(TemplateArgumentListInfo &List) const;
580  static std::size_t sizeFor(unsigned NumTemplateArgs);
581};
582
583/// \brief Extends ASTTemplateArgumentListInfo with the source location
584/// information for the template keyword; this is used as part of the
585/// representation of qualified identifiers, such as S<T>::template apply<T>.
586struct ASTTemplateKWAndArgsInfo : public ASTTemplateArgumentListInfo {
587  typedef ASTTemplateArgumentListInfo Base;
588
589  // NOTE: the source location of the (optional) template keyword is
590  // stored after all template arguments.
591
592  /// \brief Get the source location of the template keyword.
593  SourceLocation getTemplateKeywordLoc() const {
594    return *reinterpret_cast<const SourceLocation*>
595      (getTemplateArgs() + NumTemplateArgs);
596  }
597
598  /// \brief Sets the source location of the template keyword.
599  void setTemplateKeywordLoc(SourceLocation TemplateKWLoc) {
600    *reinterpret_cast<SourceLocation*>
601      (getTemplateArgs() + NumTemplateArgs) = TemplateKWLoc;
602  }
603
604  static const ASTTemplateKWAndArgsInfo*
605  Create(ASTContext &C, SourceLocation TemplateKWLoc,
606         const TemplateArgumentListInfo &List);
607
608  void initializeFrom(SourceLocation TemplateKWLoc,
609                      const TemplateArgumentListInfo &List);
610  void initializeFrom(SourceLocation TemplateKWLoc,
611                      const TemplateArgumentListInfo &List,
612                      bool &Dependent, bool &InstantiationDependent,
613                      bool &ContainsUnexpandedParameterPack);
614  void initializeFrom(SourceLocation TemplateKWLoc);
615
616  static std::size_t sizeFor(unsigned NumTemplateArgs);
617};
618
619const DiagnosticBuilder &operator<<(const DiagnosticBuilder &DB,
620                                    const TemplateArgument &Arg);
621
622inline TemplateSpecializationType::iterator
623    TemplateSpecializationType::end() const {
624  return getArgs() + getNumArgs();
625}
626
627inline DependentTemplateSpecializationType::iterator
628    DependentTemplateSpecializationType::end() const {
629  return getArgs() + getNumArgs();
630}
631
632inline const TemplateArgument &
633    TemplateSpecializationType::getArg(unsigned Idx) const {
634  assert(Idx < getNumArgs() && "Template argument out of range");
635  return getArgs()[Idx];
636}
637
638inline const TemplateArgument &
639    DependentTemplateSpecializationType::getArg(unsigned Idx) const {
640  assert(Idx < getNumArgs() && "Template argument out of range");
641  return getArgs()[Idx];
642}
643
644} // end namespace clang
645
646#endif
647