TemplateDeduction.h revision 30a2e16f6c27f888dd11eba6bbbae1e980078fcb 
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/AST/DeclTemplate.h"
17#include "clang/Basic/PartialDiagnostic.h"
18#include "llvm/ADT/SmallVector.h"
19
20namespace clang {
21
22class TemplateArgumentList;
23
24namespace sema {
25
26/// \brief Provides information about an attempted template argument
27/// deduction, whose success or failure was described by a
28/// TemplateDeductionResult value.
29class TemplateDeductionInfo {
30  /// \brief The deduced template argument list.
31  ///
32  TemplateArgumentList *Deduced;
33
34  /// \brief The source location at which template argument
35  /// deduction is occurring.
36  SourceLocation Loc;
37
38  /// \brief Have we suppressed an error during deduction?
39  bool HasSFINAEDiagnostic;
40
41  /// \brief Warnings (and follow-on notes) that were suppressed due to
42  /// SFINAE while performing template argument deduction.
43  SmallVector<PartialDiagnosticAt, 4> SuppressedDiagnostics;
44
45  TemplateDeductionInfo(const TemplateDeductionInfo &) LLVM_DELETED_FUNCTION;
46  void operator=(const TemplateDeductionInfo &) LLVM_DELETED_FUNCTION;
47
48public:
49  TemplateDeductionInfo(SourceLocation Loc)
50    : Deduced(0), Loc(Loc), HasSFINAEDiagnostic(false) { }
51
52  /// \brief Returns the location at which template argument is
53  /// occurring.
54  SourceLocation getLocation() const {
55    return Loc;
56  }
57
58  /// \brief Take ownership of the deduced template argument list.
59  TemplateArgumentList *take() {
60    TemplateArgumentList *Result = Deduced;
61    Deduced = 0;
62    return Result;
63  }
64
65  /// \brief Take ownership of the SFINAE diagnostic.
66  void takeSFINAEDiagnostic(PartialDiagnosticAt &PD) {
67    assert(HasSFINAEDiagnostic);
68    PD.first = SuppressedDiagnostics.front().first;
69    PD.second.swap(SuppressedDiagnostics.front().second);
70    SuppressedDiagnostics.clear();
71    HasSFINAEDiagnostic = false;
72  }
73
74  /// \brief Provide a new template argument list that contains the
75  /// results of template argument deduction.
76  void reset(TemplateArgumentList *NewDeduced) {
77    Deduced = NewDeduced;
78  }
79
80  /// \brief Is a SFINAE diagnostic available?
81  bool hasSFINAEDiagnostic() const {
82    return HasSFINAEDiagnostic;
83  }
84
85  /// \brief Set the diagnostic which caused the SFINAE failure.
86  void addSFINAEDiagnostic(SourceLocation Loc, PartialDiagnostic PD) {
87    // Only collect the first diagnostic.
88    if (HasSFINAEDiagnostic)
89      return;
90    SuppressedDiagnostics.clear();
91    SuppressedDiagnostics.push_back(
92        std::make_pair(Loc, PartialDiagnostic::NullDiagnostic()));
93    SuppressedDiagnostics.back().second.swap(PD);
94    HasSFINAEDiagnostic = true;
95  }
96
97  /// \brief Add a new diagnostic to the set of diagnostics
98  void addSuppressedDiagnostic(SourceLocation Loc,
99                               PartialDiagnostic PD) {
100    if (HasSFINAEDiagnostic)
101      return;
102    SuppressedDiagnostics.push_back(
103        std::make_pair(Loc, PartialDiagnostic::NullDiagnostic()));
104    SuppressedDiagnostics.back().second.swap(PD);
105  }
106
107  /// \brief Iterator over the set of suppressed diagnostics.
108  typedef SmallVectorImpl<PartialDiagnosticAt>::const_iterator
109    diag_iterator;
110
111  /// \brief Returns an iterator at the beginning of the sequence of suppressed
112  /// diagnostics.
113  diag_iterator diag_begin() const { return SuppressedDiagnostics.begin(); }
114
115  /// \brief Returns an iterator at the end of the sequence of suppressed
116  /// diagnostics.
117  diag_iterator diag_end() const { return SuppressedDiagnostics.end(); }
118
119  /// \brief The template parameter to which a template argument
120  /// deduction failure refers.
121  ///
122  /// Depending on the result of template argument deduction, this
123  /// template parameter may have different meanings:
124  ///
125  ///   TDK_Incomplete: this is the first template parameter whose
126  ///   corresponding template argument was not deduced.
127  ///
128  ///   TDK_Inconsistent: this is the template parameter for which
129  ///   two different template argument values were deduced.
130  TemplateParameter Param;
131
132  /// \brief The first template argument to which the template
133  /// argument deduction failure refers.
134  ///
135  /// Depending on the result of the template argument deduction,
136  /// this template argument may have different meanings:
137  ///
138  ///   TDK_Inconsistent: this argument is the first value deduced
139  ///   for the corresponding template parameter.
140  ///
141  ///   TDK_SubstitutionFailure: this argument is the template
142  ///   argument we were instantiating when we encountered an error.
143  ///
144  ///   TDK_NonDeducedMismatch: this is the template argument
145  ///   provided in the source code.
146  TemplateArgument FirstArg;
147
148  /// \brief The second template argument to which the template
149  /// argument deduction failure refers.
150  ///
151  /// FIXME: Finish documenting this.
152  TemplateArgument SecondArg;
153};
154
155}
156}
157
158#endif
159