TemplateBase.h revision 2be29f423acad3bbe39099a78db2805acb5bdf17 
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 "llvm/ADT/APSInt.h"
19#include "llvm/ADT/SmallVector.h"
20#include "llvm/Support/ErrorHandling.h"
21#include "clang/AST/Type.h"
22#include "clang/AST/TemplateName.h"
23
24namespace llvm {
25  class FoldingSetNodeID;
26  class raw_ostream;
27}
28
29namespace clang {
30
31class Decl;
32class DiagnosticBuilder;
33class Expr;
34struct PrintingPolicy;
35class TypeSourceInfo;
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. Its value is stored in the
47    /// TypeOrValue field.
48    Type,
49    /// The template argument is a declaration that was provided for a pointer
50    /// or reference non-type template parameter.
51    Declaration,
52    /// The template argument is an integral value stored in an llvm::APSInt
53    /// that was provided for an integral non-type template parameter.
54    Integral,
55    /// The template argument is a template name that was provided for a
56    /// template template parameter.
57    Template,
58    /// The template argument is a pack expansion of a template name that was
59    /// provided for a template template parameter.
60    TemplateExpansion,
61    /// The template argument is a value- or type-dependent expression
62    /// stored in an Expr*.
63    Expression,
64    /// The template argument is actually a parameter pack. Arguments are stored
65    /// in the Args struct.
66    Pack
67  };
68
69private:
70  /// \brief The kind of template argument we're storing.
71  unsigned Kind;
72
73  union {
74    uintptr_t TypeOrValue;
75    struct {
76      char Value[sizeof(llvm::APSInt)];
77      void *Type;
78    } Integer;
79    struct {
80      const TemplateArgument *Args;
81      unsigned NumArgs;
82    } Args;
83    struct {
84      void *Name;
85      unsigned NumExpansions;
86    } TemplateArg;
87  };
88
89  TemplateArgument(TemplateName, bool); // DO NOT USE
90
91public:
92  /// \brief Construct an empty, invalid template argument.
93  TemplateArgument() : Kind(Null), TypeOrValue(0) { }
94
95  /// \brief Construct a template type argument.
96  TemplateArgument(QualType T) : Kind(Type) {
97    TypeOrValue = reinterpret_cast<uintptr_t>(T.getAsOpaquePtr());
98  }
99
100  /// \brief Construct a template argument that refers to a
101  /// declaration, which is either an external declaration or a
102  /// template declaration.
103  TemplateArgument(Decl *D) : Kind(Declaration) {
104    // FIXME: Need to be sure we have the "canonical" declaration!
105    TypeOrValue = reinterpret_cast<uintptr_t>(D);
106  }
107
108  /// \brief Construct an integral constant template argument.
109  TemplateArgument(const llvm::APSInt &Value, QualType Type) : Kind(Integral) {
110    // FIXME: Large integral values will get leaked. Do something
111    // similar to what we did with IntegerLiteral.
112    new (Integer.Value) llvm::APSInt(Value);
113    Integer.Type = Type.getAsOpaquePtr();
114  }
115
116  /// \brief Construct a template argument that is a template.
117  ///
118  /// This form of template argument is generally used for template template
119  /// parameters. However, the template name could be a dependent template
120  /// name that ends up being instantiated to a function template whose address
121  /// is taken.
122  ///
123  /// \param Name The template name.
124  TemplateArgument(TemplateName Name) : Kind(Template)
125  {
126    TemplateArg.Name = Name.getAsVoidPointer();
127    TemplateArg.NumExpansions = 0;
128  }
129
130  /// \brief Construct a template argument that is a template pack expansion.
131  ///
132  /// This form of template argument is generally used for template template
133  /// parameters. However, the template name could be a dependent template
134  /// name that ends up being instantiated to a function template whose address
135  /// is taken.
136  ///
137  /// \param Name The template name.
138  ///
139  /// \param NumExpansions The number of expansions that will be generated by
140  /// instantiating
141  TemplateArgument(TemplateName Name, llvm::Optional<unsigned> NumExpansions)
142    : Kind(TemplateExpansion)
143  {
144    TemplateArg.Name = Name.getAsVoidPointer();
145    if (NumExpansions)
146      TemplateArg.NumExpansions = *NumExpansions + 1;
147    else
148      TemplateArg.NumExpansions = 0;
149  }
150
151  /// \brief Construct a template argument that is an expression.
152  ///
153  /// This form of template argument only occurs in template argument
154  /// lists used for dependent types and for expression; it will not
155  /// occur in a non-dependent, canonical template argument list.
156  TemplateArgument(Expr *E) : Kind(Expression) {
157    TypeOrValue = reinterpret_cast<uintptr_t>(E);
158  }
159
160  /// \brief Construct a template argument that is a template argument pack.
161  ///
162  /// We assume that storage for the template arguments provided
163  /// outlives the TemplateArgument itself.
164  TemplateArgument(const TemplateArgument *Args, unsigned NumArgs) : Kind(Pack){
165    this->Args.Args = Args;
166    this->Args.NumArgs = NumArgs;
167  }
168
169  /// \brief Copy constructor for a template argument.
170  TemplateArgument(const TemplateArgument &Other) : Kind(Other.Kind) {
171    // FIXME: Large integral values will get leaked. Do something
172    // similar to what we did with IntegerLiteral.
173    if (Kind == Integral) {
174      new (Integer.Value) llvm::APSInt(*Other.getAsIntegral());
175      Integer.Type = Other.Integer.Type;
176    } else if (Kind == Pack) {
177      Args.NumArgs = Other.Args.NumArgs;
178      Args.Args = Other.Args.Args;
179    } else if (Kind == Template || Kind == TemplateExpansion) {
180      TemplateArg.Name = Other.TemplateArg.Name;
181      TemplateArg.NumExpansions = Other.TemplateArg.NumExpansions;
182    } else
183      TypeOrValue = Other.TypeOrValue;
184  }
185
186  TemplateArgument& operator=(const TemplateArgument& Other) {
187    using llvm::APSInt;
188
189    if (Kind == Other.Kind && Kind == Integral) {
190      // Copy integral values.
191      *this->getAsIntegral() = *Other.getAsIntegral();
192      Integer.Type = Other.Integer.Type;
193      return *this;
194    }
195
196    // Destroy the current integral value, if that's what we're holding.
197    if (Kind == Integral)
198      getAsIntegral()->~APSInt();
199
200    Kind = Other.Kind;
201
202    if (Other.Kind == Integral) {
203      new (Integer.Value) llvm::APSInt(*Other.getAsIntegral());
204      Integer.Type = Other.Integer.Type;
205    } else if (Other.Kind == Pack) {
206      Args.NumArgs = Other.Args.NumArgs;
207      Args.Args = Other.Args.Args;
208    } else if (Kind == Template || Kind == TemplateExpansion) {
209      TemplateArg.Name = Other.TemplateArg.Name;
210      TemplateArg.NumExpansions = Other.TemplateArg.NumExpansions;
211    } else {
212      TypeOrValue = Other.TypeOrValue;
213    }
214
215    return *this;
216  }
217
218  ~TemplateArgument() {
219    using llvm::APSInt;
220
221    if (Kind == Integral)
222      getAsIntegral()->~APSInt();
223  }
224
225  /// \brief Create a new template argument pack by copying the given set of
226  /// template arguments.
227  static TemplateArgument CreatePackCopy(ASTContext &Context,
228                                         const TemplateArgument *Args,
229                                         unsigned NumArgs);
230
231  /// \brief Return the kind of stored template argument.
232  ArgKind getKind() const { return (ArgKind)Kind; }
233
234  /// \brief Determine whether this template argument has no value.
235  bool isNull() const { return Kind == Null; }
236
237  /// \brief Whether this template argument is dependent on a template
238  /// parameter.
239  bool isDependent() const;
240
241  /// \brief Whether this template argument contains an unexpanded
242  /// parameter pack.
243  bool containsUnexpandedParameterPack() const;
244
245  /// \brief Determine whether this template argument is a pack expansion.
246  bool isPackExpansion() const;
247
248  /// \brief Retrieve the template argument as a type.
249  QualType getAsType() const {
250    if (Kind != Type)
251      return QualType();
252
253    return QualType::getFromOpaquePtr(reinterpret_cast<void*>(TypeOrValue));
254  }
255
256  /// \brief Retrieve the template argument as a declaration.
257  Decl *getAsDecl() const {
258    if (Kind != Declaration)
259      return 0;
260    return reinterpret_cast<Decl *>(TypeOrValue);
261  }
262
263  /// \brief Retrieve the template argument as a template name.
264  TemplateName getAsTemplate() const {
265    if (Kind != Template)
266      return TemplateName();
267
268    return TemplateName::getFromVoidPointer(TemplateArg.Name);
269  }
270
271  /// \brief Retrieve the template argument as a template name; if the argument
272  /// is a pack expansion, return the pattern as a template name.
273  TemplateName getAsTemplateOrTemplatePattern() const {
274    if (Kind != Template && Kind != TemplateExpansion)
275      return TemplateName();
276
277    return TemplateName::getFromVoidPointer(TemplateArg.Name);
278  }
279
280  /// \brief Retrieve the number of expansions that a template template argument
281  /// expansion will produce, if known.
282  llvm::Optional<unsigned> getNumTemplateExpansions() const;
283
284  /// \brief Retrieve the template argument as an integral value.
285  llvm::APSInt *getAsIntegral() {
286    if (Kind != Integral)
287      return 0;
288    return reinterpret_cast<llvm::APSInt*>(&Integer.Value[0]);
289  }
290
291  const llvm::APSInt *getAsIntegral() const {
292    return const_cast<TemplateArgument*>(this)->getAsIntegral();
293  }
294
295  /// \brief Retrieve the type of the integral value.
296  QualType getIntegralType() const {
297    if (Kind != Integral)
298      return QualType();
299
300    return QualType::getFromOpaquePtr(Integer.Type);
301  }
302
303  void setIntegralType(QualType T) {
304    assert(Kind == Integral &&
305           "Cannot set the integral type of a non-integral template argument");
306    Integer.Type = T.getAsOpaquePtr();
307  }
308
309  /// \brief Retrieve the template argument as an expression.
310  Expr *getAsExpr() const {
311    if (Kind != Expression)
312      return 0;
313
314    return reinterpret_cast<Expr *>(TypeOrValue);
315  }
316
317  /// \brief Iterator that traverses the elements of a template argument pack.
318  typedef const TemplateArgument * pack_iterator;
319
320  /// \brief Iterator referencing the first argument of a template argument
321  /// pack.
322  pack_iterator pack_begin() const {
323    assert(Kind == Pack);
324    return Args.Args;
325  }
326
327  /// \brief Iterator referencing one past the last argument of a template
328  /// argument pack.
329  pack_iterator pack_end() const {
330    assert(Kind == Pack);
331    return Args.Args + Args.NumArgs;
332  }
333
334  /// \brief The number of template arguments in the given template argument
335  /// pack.
336  unsigned pack_size() const {
337    assert(Kind == Pack);
338    return Args.NumArgs;
339  }
340
341  /// Determines whether two template arguments are superficially the
342  /// same.
343  bool structurallyEquals(const TemplateArgument &Other) const;
344
345  /// \brief When the template argument is a pack expansion, returns
346  /// the pattern of the pack expansion.
347  ///
348  /// \param Ellipsis Will be set to the location of the ellipsis.
349  TemplateArgument getPackExpansionPattern() const;
350
351  /// \brief Print this template argument to the given output stream.
352  void print(const PrintingPolicy &Policy, llvm::raw_ostream &Out) const;
353
354  /// \brief Used to insert TemplateArguments into FoldingSets.
355  void Profile(llvm::FoldingSetNodeID &ID, const ASTContext &Context) const;
356};
357
358/// Location information for a TemplateArgument.
359struct TemplateArgumentLocInfo {
360private:
361  union {
362    Expr *Expression;
363    TypeSourceInfo *Declarator;
364    struct {
365      unsigned QualifierRange[2];
366      unsigned TemplateNameLoc;
367      unsigned EllipsisLoc;
368    } Template;
369  };
370
371public:
372  TemplateArgumentLocInfo();
373
374  TemplateArgumentLocInfo(TypeSourceInfo *TInfo) : Declarator(TInfo) {}
375
376  TemplateArgumentLocInfo(Expr *E) : Expression(E) {}
377
378  TemplateArgumentLocInfo(SourceRange QualifierRange,
379                          SourceLocation TemplateNameLoc,
380                          SourceLocation EllipsisLoc)
381  {
382    Template.QualifierRange[0] = QualifierRange.getBegin().getRawEncoding();
383    Template.QualifierRange[1] = QualifierRange.getEnd().getRawEncoding();
384    Template.TemplateNameLoc = TemplateNameLoc.getRawEncoding();
385    Template.EllipsisLoc = EllipsisLoc.getRawEncoding();
386  }
387
388  TypeSourceInfo *getAsTypeSourceInfo() const {
389    return Declarator;
390  }
391
392  Expr *getAsExpr() const {
393    return Expression;
394  }
395
396  SourceRange getTemplateQualifierRange() const {
397    return SourceRange(
398                SourceLocation::getFromRawEncoding(Template.QualifierRange[0]),
399                SourceLocation::getFromRawEncoding(Template.QualifierRange[1]));
400  }
401
402  SourceLocation getTemplateNameLoc() const {
403    return SourceLocation::getFromRawEncoding(Template.TemplateNameLoc);
404  }
405
406  SourceLocation getTemplateEllipsisLoc() const {
407    return SourceLocation::getFromRawEncoding(Template.EllipsisLoc);
408  }
409};
410
411/// Location wrapper for a TemplateArgument.  TemplateArgument is to
412/// TemplateArgumentLoc as Type is to TypeLoc.
413class TemplateArgumentLoc {
414  TemplateArgument Argument;
415  TemplateArgumentLocInfo LocInfo;
416
417public:
418  TemplateArgumentLoc() {}
419
420  TemplateArgumentLoc(const TemplateArgument &Argument,
421                      TemplateArgumentLocInfo Opaque)
422    : Argument(Argument), LocInfo(Opaque) {
423  }
424
425  TemplateArgumentLoc(const TemplateArgument &Argument, TypeSourceInfo *TInfo)
426    : Argument(Argument), LocInfo(TInfo) {
427    assert(Argument.getKind() == TemplateArgument::Type);
428  }
429
430  TemplateArgumentLoc(const TemplateArgument &Argument, Expr *E)
431    : Argument(Argument), LocInfo(E) {
432    assert(Argument.getKind() == TemplateArgument::Expression);
433  }
434
435  TemplateArgumentLoc(const TemplateArgument &Argument,
436                      SourceRange QualifierRange,
437                      SourceLocation TemplateNameLoc,
438                      SourceLocation EllipsisLoc = SourceLocation())
439    : Argument(Argument),
440      LocInfo(QualifierRange, TemplateNameLoc, EllipsisLoc) {
441    assert(Argument.getKind() == TemplateArgument::Template ||
442           Argument.getKind() == TemplateArgument::TemplateExpansion);
443  }
444
445  /// \brief - Fetches the primary location of the argument.
446  SourceLocation getLocation() const {
447    if (Argument.getKind() == TemplateArgument::Template ||
448        Argument.getKind() == TemplateArgument::TemplateExpansion)
449      return getTemplateNameLoc();
450
451    return getSourceRange().getBegin();
452  }
453
454  /// \brief - Fetches the full source range of the argument.
455  SourceRange getSourceRange() const;
456
457  const TemplateArgument &getArgument() const {
458    return Argument;
459  }
460
461  TemplateArgumentLocInfo getLocInfo() const {
462    return LocInfo;
463  }
464
465  TypeSourceInfo *getTypeSourceInfo() const {
466    assert(Argument.getKind() == TemplateArgument::Type);
467    return LocInfo.getAsTypeSourceInfo();
468  }
469
470  Expr *getSourceExpression() const {
471    assert(Argument.getKind() == TemplateArgument::Expression);
472    return LocInfo.getAsExpr();
473  }
474
475  Expr *getSourceDeclExpression() const {
476    assert(Argument.getKind() == TemplateArgument::Declaration);
477    return LocInfo.getAsExpr();
478  }
479
480  SourceRange getTemplateQualifierRange() const {
481    assert(Argument.getKind() == TemplateArgument::Template ||
482           Argument.getKind() == TemplateArgument::TemplateExpansion);
483    return LocInfo.getTemplateQualifierRange();
484  }
485
486  SourceLocation getTemplateNameLoc() const {
487    assert(Argument.getKind() == TemplateArgument::Template ||
488           Argument.getKind() == TemplateArgument::TemplateExpansion);
489    return LocInfo.getTemplateNameLoc();
490  }
491
492  SourceLocation getTemplateEllipsisLoc() const {
493    assert(Argument.getKind() == TemplateArgument::TemplateExpansion);
494    return LocInfo.getTemplateEllipsisLoc();
495  }
496
497  /// \brief When the template argument is a pack expansion, returns
498  /// the pattern of the pack expansion.
499  ///
500  /// \param Ellipsis Will be set to the location of the ellipsis.
501  ///
502  /// \param NumExpansions Will be set to the number of expansions that will
503  /// be generated from this pack expansion, if known a priori.
504  TemplateArgumentLoc getPackExpansionPattern(SourceLocation &Ellipsis,
505                                        llvm::Optional<unsigned> &NumExpansions,
506                                              ASTContext &Context) const;
507};
508
509/// A convenient class for passing around template argument
510/// information.  Designed to be passed by reference.
511class TemplateArgumentListInfo {
512  llvm::SmallVector<TemplateArgumentLoc, 8> Arguments;
513  SourceLocation LAngleLoc;
514  SourceLocation RAngleLoc;
515
516public:
517  TemplateArgumentListInfo() {}
518
519  TemplateArgumentListInfo(SourceLocation LAngleLoc,
520                           SourceLocation RAngleLoc)
521    : LAngleLoc(LAngleLoc), RAngleLoc(RAngleLoc) {}
522
523  SourceLocation getLAngleLoc() const { return LAngleLoc; }
524  SourceLocation getRAngleLoc() const { return RAngleLoc; }
525
526  void setLAngleLoc(SourceLocation Loc) { LAngleLoc = Loc; }
527  void setRAngleLoc(SourceLocation Loc) { RAngleLoc = Loc; }
528
529  unsigned size() const { return Arguments.size(); }
530
531  const TemplateArgumentLoc *getArgumentArray() const {
532    return Arguments.data();
533  }
534
535  const TemplateArgumentLoc &operator[](unsigned I) const {
536    return Arguments[I];
537  }
538
539  void addArgument(const TemplateArgumentLoc &Loc) {
540    Arguments.push_back(Loc);
541  }
542};
543
544const DiagnosticBuilder &operator<<(const DiagnosticBuilder &DB,
545                                    const TemplateArgument &Arg);
546
547inline TemplateSpecializationType::iterator
548    TemplateSpecializationType::end() const {
549  return getArgs() + getNumArgs();
550}
551
552inline DependentTemplateSpecializationType::iterator
553    DependentTemplateSpecializationType::end() const {
554  return getArgs() + getNumArgs();
555}
556
557inline const TemplateArgument &
558    TemplateSpecializationType::getArg(unsigned Idx) const {
559  assert(Idx < getNumArgs() && "Template argument out of range");
560  return getArgs()[Idx];
561}
562
563inline const TemplateArgument &
564    DependentTemplateSpecializationType::getArg(unsigned Idx) const {
565  assert(Idx < getNumArgs() && "Template argument out of range");
566  return getArgs()[Idx];
567}
568
569} // end namespace clang
570
571#endif
572