TemplateDeduction.h revision b8590f3572158bde97f14037c4cc8f4a57c8d810 
1//===- TemplateDeduction.h - C++ template argument deduction ----*- 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//  This file provides types used with Sema's template argument deduction
10// routines.
11//
12//===----------------------------------------------------------------------===/
13#ifndef LLVM_CLANG_SEMA_TEMPLATE_DEDUCTION_H
14#define LLVM_CLANG_SEMA_TEMPLATE_DEDUCTION_H
15
16#include "clang/Basic/PartialDiagnostic.h"
17#include "clang/AST/DeclTemplate.h"
18#include "llvm/ADT/SmallVector.h"
19
20namespace clang {
21
22class ASTContext;
23class TemplateArgumentList;
24
25namespace sema {
26
27/// \brief Provides information about an attempted template argument
28/// deduction, whose success or failure was described by a
29/// TemplateDeductionResult value.
30class TemplateDeductionInfo {
31  /// \brief The context in which the template arguments are stored.
32  ASTContext &Context;
33
34  /// \brief The deduced template argument list.
35  ///
36  TemplateArgumentList *Deduced;
37
38  /// \brief The source location at which template argument
39  /// deduction is occurring.
40  SourceLocation Loc;
41
42  /// \brief Have we suppressed an error during deduction?
43  bool HasSFINAEDiagnostic;
44
45  /// \brief Warnings (and follow-on notes) that were suppressed due to
46  /// SFINAE while performing template argument deduction.
47  SmallVector<PartialDiagnosticAt, 4> SuppressedDiagnostics;
48
49  // do not implement these
50  TemplateDeductionInfo(const TemplateDeductionInfo&);
51  TemplateDeductionInfo &operator=(const TemplateDeductionInfo&);
52
53public:
54  TemplateDeductionInfo(ASTContext &Context, SourceLocation Loc)
55    : Context(Context), Deduced(0), Loc(Loc), HasSFINAEDiagnostic(false) { }
56
57  ~TemplateDeductionInfo() {
58    // FIXME: if (Deduced) Deduced->Destroy(Context);
59  }
60
61  /// \brief Returns the location at which template argument is
62  /// occurring.
63  SourceLocation getLocation() const {
64    return Loc;
65  }
66
67  /// \brief Take ownership of the deduced template argument list.
68  TemplateArgumentList *take() {
69    TemplateArgumentList *Result = Deduced;
70    Deduced = 0;
71    return Result;
72  }
73
74  /// \brief Take ownership of the SFINAE diagnostic.
75  void takeSFINAEDiagnostic(PartialDiagnosticAt &PD) {
76    assert(HasSFINAEDiagnostic);
77    PD.first = SuppressedDiagnostics.front().first;
78    PD.second.swap(SuppressedDiagnostics.front().second);
79    SuppressedDiagnostics.clear();
80    HasSFINAEDiagnostic = false;
81  }
82
83  /// \brief Provide a new template argument list that contains the
84  /// results of template argument deduction.
85  void reset(TemplateArgumentList *NewDeduced) {
86    // FIXME: if (Deduced) Deduced->Destroy(Context);
87    Deduced = NewDeduced;
88  }
89
90  /// \brief Is a SFINAE diagnostic available?
91  bool hasSFINAEDiagnostic() const {
92    return HasSFINAEDiagnostic;
93  }
94
95  /// \brief Set the diagnostic which caused the SFINAE failure.
96  void addSFINAEDiagnostic(SourceLocation Loc, PartialDiagnostic PD) {
97    // Only collect the first diagnostic.
98    if (HasSFINAEDiagnostic)
99      return;
100    SuppressedDiagnostics.clear();
101    SuppressedDiagnostics.push_back(
102        std::make_pair(Loc, PartialDiagnostic::NullDiagnostic()));
103    SuppressedDiagnostics.back().second.swap(PD);
104    HasSFINAEDiagnostic = true;
105  }
106
107  /// \brief Add a new diagnostic to the set of diagnostics
108  void addSuppressedDiagnostic(SourceLocation Loc,
109                               PartialDiagnostic PD) {
110    if (HasSFINAEDiagnostic)
111      return;
112    SuppressedDiagnostics.push_back(
113        std::make_pair(Loc, PartialDiagnostic::NullDiagnostic()));
114    SuppressedDiagnostics.back().second.swap(PD);
115  }
116
117  /// \brief Iterator over the set of suppressed diagnostics.
118  typedef SmallVectorImpl<PartialDiagnosticAt>::const_iterator
119    diag_iterator;
120
121  /// \brief Returns an iterator at the beginning of the sequence of suppressed
122  /// diagnostics.
123  diag_iterator diag_begin() const { return SuppressedDiagnostics.begin(); }
124
125  /// \brief Returns an iterator at the end of the sequence of suppressed
126  /// diagnostics.
127  diag_iterator diag_end() const { return SuppressedDiagnostics.end(); }
128
129  /// \brief The template parameter to which a template argument
130  /// deduction failure refers.
131  ///
132  /// Depending on the result of template argument deduction, this
133  /// template parameter may have different meanings:
134  ///
135  ///   TDK_Incomplete: this is the first template parameter whose
136  ///   corresponding template argument was not deduced.
137  ///
138  ///   TDK_Inconsistent: this is the template parameter for which
139  ///   two different template argument values were deduced.
140  TemplateParameter Param;
141
142  /// \brief The first template argument to which the template
143  /// argument deduction failure refers.
144  ///
145  /// Depending on the result of the template argument deduction,
146  /// this template argument may have different meanings:
147  ///
148  ///   TDK_Inconsistent: this argument is the first value deduced
149  ///   for the corresponding template parameter.
150  ///
151  ///   TDK_SubstitutionFailure: this argument is the template
152  ///   argument we were instantiating when we encountered an error.
153  ///
154  ///   TDK_NonDeducedMismatch: this is the template argument
155  ///   provided in the source code.
156  TemplateArgument FirstArg;
157
158  /// \brief The second template argument to which the template
159  /// argument deduction failure refers.
160  ///
161  /// FIXME: Finish documenting this.
162  TemplateArgument SecondArg;
163};
164
165}
166}
167
168#endif
169