TemplateBase.h revision 87dd697dcc8ecb64df73ae64d61b8c80ff0c157c 
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 value- or type-dependent expression
59    /// stored in an Expr*.
60    Expression,
61    /// The template argument is actually a parameter pack. Arguments are stored
62    /// in the Args struct.
63    Pack
64  };
65
66private:
67  /// \brief The kind of template argument we're storing.
68  unsigned Kind;
69
70  union {
71    uintptr_t TypeOrValue;
72    struct {
73      char Value[sizeof(llvm::APSInt)];
74      void *Type;
75    } Integer;
76    struct {
77      TemplateArgument *Args;
78      unsigned NumArgs;
79    } Args;
80  };
81
82public:
83  /// \brief Construct an empty, invalid template argument.
84  TemplateArgument() : Kind(Null), TypeOrValue(0) { }
85
86  /// \brief Construct a template type argument.
87  TemplateArgument(QualType T) : Kind(Type) {
88    TypeOrValue = reinterpret_cast<uintptr_t>(T.getAsOpaquePtr());
89  }
90
91  /// \brief Construct a template argument that refers to a
92  /// declaration, which is either an external declaration or a
93  /// template declaration.
94  TemplateArgument(Decl *D) : Kind(Declaration) {
95    // FIXME: Need to be sure we have the "canonical" declaration!
96    TypeOrValue = reinterpret_cast<uintptr_t>(D);
97  }
98
99  /// \brief Construct an integral constant template argument.
100  TemplateArgument(const llvm::APSInt &Value, QualType Type) : Kind(Integral) {
101    // FIXME: Large integral values will get leaked. Do something
102    // similar to what we did with IntegerLiteral.
103    new (Integer.Value) llvm::APSInt(Value);
104    Integer.Type = Type.getAsOpaquePtr();
105  }
106
107  /// \brief Construct a template argument that is a template.
108  ///
109  /// This form of template argument is generally used for template template
110  /// parameters. However, the template name could be a dependent template
111  /// name that ends up being instantiated to a function template whose address
112  /// is taken.
113  TemplateArgument(TemplateName Name) : Kind(Template) {
114    TypeOrValue = reinterpret_cast<uintptr_t>(Name.getAsVoidPointer());
115  }
116
117  /// \brief Construct a template argument that is an expression.
118  ///
119  /// This form of template argument only occurs in template argument
120  /// lists used for dependent types and for expression; it will not
121  /// occur in a non-dependent, canonical template argument list.
122  TemplateArgument(Expr *E) : Kind(Expression) {
123    TypeOrValue = reinterpret_cast<uintptr_t>(E);
124  }
125
126  /// \brief Construct a template argument that is a template argument pack.
127  ///
128  /// We assume that storage for the template arguments provided
129  /// outlives the TemplateArgument itself.
130  TemplateArgument(TemplateArgument *Args, unsigned NumArgs) : Kind(Pack) {
131    this->Args.Args = Args;
132    this->Args.NumArgs = NumArgs;
133  }
134
135  /// \brief Copy constructor for a template argument.
136  TemplateArgument(const TemplateArgument &Other) : Kind(Other.Kind) {
137    // FIXME: Large integral values will get leaked. Do something
138    // similar to what we did with IntegerLiteral.
139    if (Kind == Integral) {
140      new (Integer.Value) llvm::APSInt(*Other.getAsIntegral());
141      Integer.Type = Other.Integer.Type;
142    } else if (Kind == Pack) {
143      Args.NumArgs = Other.Args.NumArgs;
144      Args.Args = Other.Args.Args;
145    }
146    else
147      TypeOrValue = Other.TypeOrValue;
148  }
149
150  TemplateArgument& operator=(const TemplateArgument& Other) {
151    using llvm::APSInt;
152
153    if (Kind == Other.Kind && Kind == Integral) {
154      // Copy integral values.
155      *this->getAsIntegral() = *Other.getAsIntegral();
156      Integer.Type = Other.Integer.Type;
157      return *this;
158    }
159
160    // Destroy the current integral value, if that's what we're holding.
161    if (Kind == Integral)
162      getAsIntegral()->~APSInt();
163
164    Kind = Other.Kind;
165
166    if (Other.Kind == Integral) {
167      new (Integer.Value) llvm::APSInt(*Other.getAsIntegral());
168      Integer.Type = Other.Integer.Type;
169    } else if (Other.Kind == Pack) {
170      Args.NumArgs = Other.Args.NumArgs;
171      Args.Args = Other.Args.Args;
172    } else {
173      TypeOrValue = Other.TypeOrValue;
174    }
175
176    return *this;
177  }
178
179  ~TemplateArgument() {
180    using llvm::APSInt;
181
182    if (Kind == Integral)
183      getAsIntegral()->~APSInt();
184  }
185
186  /// \brief Return the kind of stored template argument.
187  ArgKind getKind() const { return (ArgKind)Kind; }
188
189  /// \brief Determine whether this template argument has no value.
190  bool isNull() const { return Kind == Null; }
191
192  /// \brief Whether this template argument is dependent on a template
193  /// parameter.
194  bool isDependent() const;
195
196  /// \brief Whether this template argument contains an unexpanded
197  /// parameter pack.
198  bool containsUnexpandedParameterPack() const;
199
200  /// \brief Retrieve the template argument as a type.
201  QualType getAsType() const {
202    if (Kind != Type)
203      return QualType();
204
205    return QualType::getFromOpaquePtr(reinterpret_cast<void*>(TypeOrValue));
206  }
207
208  /// \brief Retrieve the template argument as a declaration.
209  Decl *getAsDecl() const {
210    if (Kind != Declaration)
211      return 0;
212    return reinterpret_cast<Decl *>(TypeOrValue);
213  }
214
215  /// \brief Retrieve the template argument as a template name.
216  TemplateName getAsTemplate() const {
217    if (Kind != Template)
218      return TemplateName();
219
220    return TemplateName::getFromVoidPointer(
221                                        reinterpret_cast<void *> (TypeOrValue));
222  }
223
224  /// \brief Retrieve the template argument as an integral value.
225  llvm::APSInt *getAsIntegral() {
226    if (Kind != Integral)
227      return 0;
228    return reinterpret_cast<llvm::APSInt*>(&Integer.Value[0]);
229  }
230
231  const llvm::APSInt *getAsIntegral() const {
232    return const_cast<TemplateArgument*>(this)->getAsIntegral();
233  }
234
235  /// \brief Retrieve the type of the integral value.
236  QualType getIntegralType() const {
237    if (Kind != Integral)
238      return QualType();
239
240    return QualType::getFromOpaquePtr(Integer.Type);
241  }
242
243  void setIntegralType(QualType T) {
244    assert(Kind == Integral &&
245           "Cannot set the integral type of a non-integral template argument");
246    Integer.Type = T.getAsOpaquePtr();
247  }
248
249  /// \brief Retrieve the template argument as an expression.
250  Expr *getAsExpr() const {
251    if (Kind != Expression)
252      return 0;
253
254    return reinterpret_cast<Expr *>(TypeOrValue);
255  }
256
257  /// \brief Iterator that traverses the elements of a template argument pack.
258  typedef const TemplateArgument * pack_iterator;
259
260  /// \brief Iterator referencing the first argument of a template argument
261  /// pack.
262  pack_iterator pack_begin() const {
263    assert(Kind == Pack);
264    return Args.Args;
265  }
266
267  /// \brief Iterator referencing one past the last argument of a template
268  /// argument pack.
269  pack_iterator pack_end() const {
270    assert(Kind == Pack);
271    return Args.Args + Args.NumArgs;
272  }
273
274  /// \brief The number of template arguments in the given template argument
275  /// pack.
276  unsigned pack_size() const {
277    assert(Kind == Pack);
278    return Args.NumArgs;
279  }
280
281  /// Determines whether two template arguments are superficially the
282  /// same.
283  bool structurallyEquals(const TemplateArgument &Other) const;
284
285  /// \brief Print this template argument to the given output stream.
286  void print(const PrintingPolicy &Policy, llvm::raw_ostream &Out) const;
287
288  /// \brief Used to insert TemplateArguments into FoldingSets.
289  void Profile(llvm::FoldingSetNodeID &ID, ASTContext &Context) const;
290};
291
292/// Location information for a TemplateArgument.
293struct TemplateArgumentLocInfo {
294private:
295  union {
296    Expr *Expression;
297    TypeSourceInfo *Declarator;
298    struct {
299      unsigned QualifierRange[2];
300      unsigned TemplateNameLoc;
301    } Template;
302  };
303
304public:
305  TemplateArgumentLocInfo() : Expression(0) {}
306
307  TemplateArgumentLocInfo(TypeSourceInfo *TInfo) : Declarator(TInfo) {}
308
309  TemplateArgumentLocInfo(Expr *E) : Expression(E) {}
310
311  TemplateArgumentLocInfo(SourceRange QualifierRange,
312                          SourceLocation TemplateNameLoc)
313  {
314    Template.QualifierRange[0] = QualifierRange.getBegin().getRawEncoding();
315    Template.QualifierRange[1] = QualifierRange.getEnd().getRawEncoding();
316    Template.TemplateNameLoc = TemplateNameLoc.getRawEncoding();
317  }
318
319  TypeSourceInfo *getAsTypeSourceInfo() const {
320    return Declarator;
321  }
322
323  Expr *getAsExpr() const {
324    return Expression;
325  }
326
327  SourceRange getTemplateQualifierRange() const {
328    return SourceRange(
329                SourceLocation::getFromRawEncoding(Template.QualifierRange[0]),
330                SourceLocation::getFromRawEncoding(Template.QualifierRange[1]));
331  }
332
333  SourceLocation getTemplateNameLoc() const {
334    return SourceLocation::getFromRawEncoding(Template.TemplateNameLoc);
335  }
336};
337
338/// Location wrapper for a TemplateArgument.  TemplateArgument is to
339/// TemplateArgumentLoc as Type is to TypeLoc.
340class TemplateArgumentLoc {
341  TemplateArgument Argument;
342  TemplateArgumentLocInfo LocInfo;
343
344public:
345  TemplateArgumentLoc() {}
346
347  TemplateArgumentLoc(const TemplateArgument &Argument,
348                      TemplateArgumentLocInfo Opaque)
349    : Argument(Argument), LocInfo(Opaque) {
350  }
351
352  TemplateArgumentLoc(const TemplateArgument &Argument, TypeSourceInfo *TInfo)
353    : Argument(Argument), LocInfo(TInfo) {
354    assert(Argument.getKind() == TemplateArgument::Type);
355  }
356
357  TemplateArgumentLoc(const TemplateArgument &Argument, Expr *E)
358    : Argument(Argument), LocInfo(E) {
359    assert(Argument.getKind() == TemplateArgument::Expression);
360  }
361
362  TemplateArgumentLoc(const TemplateArgument &Argument,
363                      SourceRange QualifierRange,
364                      SourceLocation TemplateNameLoc)
365    : Argument(Argument), LocInfo(QualifierRange, TemplateNameLoc) {
366    assert(Argument.getKind() == TemplateArgument::Template);
367  }
368
369  /// \brief - Fetches the primary location of the argument.
370  SourceLocation getLocation() const {
371    if (Argument.getKind() == TemplateArgument::Template)
372      return getTemplateNameLoc();
373
374    return getSourceRange().getBegin();
375  }
376
377  /// \brief - Fetches the full source range of the argument.
378  SourceRange getSourceRange() const;
379
380  const TemplateArgument &getArgument() const {
381    return Argument;
382  }
383
384  TemplateArgumentLocInfo getLocInfo() const {
385    return LocInfo;
386  }
387
388  TypeSourceInfo *getTypeSourceInfo() const {
389    assert(Argument.getKind() == TemplateArgument::Type);
390    return LocInfo.getAsTypeSourceInfo();
391  }
392
393  Expr *getSourceExpression() const {
394    assert(Argument.getKind() == TemplateArgument::Expression);
395    return LocInfo.getAsExpr();
396  }
397
398  Expr *getSourceDeclExpression() const {
399    assert(Argument.getKind() == TemplateArgument::Declaration);
400    return LocInfo.getAsExpr();
401  }
402
403  SourceRange getTemplateQualifierRange() const {
404    assert(Argument.getKind() == TemplateArgument::Template);
405    return LocInfo.getTemplateQualifierRange();
406  }
407
408  SourceLocation getTemplateNameLoc() const {
409    assert(Argument.getKind() == TemplateArgument::Template);
410    return LocInfo.getTemplateNameLoc();
411  }
412};
413
414/// A convenient class for passing around template argument
415/// information.  Designed to be passed by reference.
416class TemplateArgumentListInfo {
417  llvm::SmallVector<TemplateArgumentLoc, 8> Arguments;
418  SourceLocation LAngleLoc;
419  SourceLocation RAngleLoc;
420
421public:
422  TemplateArgumentListInfo() {}
423
424  TemplateArgumentListInfo(SourceLocation LAngleLoc,
425                           SourceLocation RAngleLoc)
426    : LAngleLoc(LAngleLoc), RAngleLoc(RAngleLoc) {}
427
428  SourceLocation getLAngleLoc() const { return LAngleLoc; }
429  SourceLocation getRAngleLoc() const { return RAngleLoc; }
430
431  void setLAngleLoc(SourceLocation Loc) { LAngleLoc = Loc; }
432  void setRAngleLoc(SourceLocation Loc) { RAngleLoc = Loc; }
433
434  unsigned size() const { return Arguments.size(); }
435
436  const TemplateArgumentLoc *getArgumentArray() const {
437    return Arguments.data();
438  }
439
440  const TemplateArgumentLoc &operator[](unsigned I) const {
441    return Arguments[I];
442  }
443
444  void addArgument(const TemplateArgumentLoc &Loc) {
445    Arguments.push_back(Loc);
446  }
447};
448
449const DiagnosticBuilder &operator<<(const DiagnosticBuilder &DB,
450                                    const TemplateArgument &Arg);
451
452inline TemplateSpecializationType::iterator
453    TemplateSpecializationType::end() const {
454  return getArgs() + getNumArgs();
455}
456
457inline DependentTemplateSpecializationType::iterator
458    DependentTemplateSpecializationType::end() const {
459  return getArgs() + getNumArgs();
460}
461
462inline const TemplateArgument &
463    TemplateSpecializationType::getArg(unsigned Idx) const {
464  assert(Idx < getNumArgs() && "Template argument out of range");
465  return getArgs()[Idx];
466}
467
468inline const TemplateArgument &
469    DependentTemplateSpecializationType::getArg(unsigned Idx) const {
470  assert(Idx < getNumArgs() && "Template argument out of range");
471  return getArgs()[Idx];
472}
473
474} // end namespace clang
475
476#endif
477