TemplateDeduction.h revision f56faa01936b9cf909623d7f06e3c2569ca4a78e 
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  TemplateDeductionInfo(const TemplateDeductionInfo &) LLVM_DELETED_FUNCTION;
50  void operator=(const TemplateDeductionInfo &) LLVM_DELETED_FUNCTION;
51
52public:
53  TemplateDeductionInfo(ASTContext &Context, SourceLocation Loc)
54    : Context(Context), Deduced(0), Loc(Loc), HasSFINAEDiagnostic(false) { }
55
56  ~TemplateDeductionInfo() {
57    // FIXME: if (Deduced) Deduced->Destroy(Context);
58  }
59
60  /// \brief Returns the location at which template argument is
61  /// occurring.
62  SourceLocation getLocation() const {
63    return Loc;
64  }
65
66  /// \brief Take ownership of the deduced template argument list.
67  TemplateArgumentList *take() {
68    TemplateArgumentList *Result = Deduced;
69    Deduced = 0;
70    return Result;
71  }
72
73  /// \brief Take ownership of the SFINAE diagnostic.
74  void takeSFINAEDiagnostic(PartialDiagnosticAt &PD) {
75    assert(HasSFINAEDiagnostic);
76    PD.first = SuppressedDiagnostics.front().first;
77    PD.second.swap(SuppressedDiagnostics.front().second);
78    SuppressedDiagnostics.clear();
79    HasSFINAEDiagnostic = false;
80  }
81
82  /// \brief Provide a new template argument list that contains the
83  /// results of template argument deduction.
84  void reset(TemplateArgumentList *NewDeduced) {
85    // FIXME: if (Deduced) Deduced->Destroy(Context);
86    Deduced = NewDeduced;
87  }
88
89  /// \brief Is a SFINAE diagnostic available?
90  bool hasSFINAEDiagnostic() const {
91    return HasSFINAEDiagnostic;
92  }
93
94  /// \brief Set the diagnostic which caused the SFINAE failure.
95  void addSFINAEDiagnostic(SourceLocation Loc, PartialDiagnostic PD) {
96    // Only collect the first diagnostic.
97    if (HasSFINAEDiagnostic)
98      return;
99    SuppressedDiagnostics.clear();
100    SuppressedDiagnostics.push_back(
101        std::make_pair(Loc, PartialDiagnostic::NullDiagnostic()));
102    SuppressedDiagnostics.back().second.swap(PD);
103    HasSFINAEDiagnostic = true;
104  }
105
106  /// \brief Add a new diagnostic to the set of diagnostics
107  void addSuppressedDiagnostic(SourceLocation Loc,
108                               PartialDiagnostic PD) {
109    if (HasSFINAEDiagnostic)
110      return;
111    SuppressedDiagnostics.push_back(
112        std::make_pair(Loc, PartialDiagnostic::NullDiagnostic()));
113    SuppressedDiagnostics.back().second.swap(PD);
114  }
115
116  /// \brief Iterator over the set of suppressed diagnostics.
117  typedef SmallVectorImpl<PartialDiagnosticAt>::const_iterator
118    diag_iterator;
119
120  /// \brief Returns an iterator at the beginning of the sequence of suppressed
121  /// diagnostics.
122  diag_iterator diag_begin() const { return SuppressedDiagnostics.begin(); }
123
124  /// \brief Returns an iterator at the end of the sequence of suppressed
125  /// diagnostics.
126  diag_iterator diag_end() const { return SuppressedDiagnostics.end(); }
127
128  /// \brief The template parameter to which a template argument
129  /// deduction failure refers.
130  ///
131  /// Depending on the result of template argument deduction, this
132  /// template parameter may have different meanings:
133  ///
134  ///   TDK_Incomplete: this is the first template parameter whose
135  ///   corresponding template argument was not deduced.
136  ///
137  ///   TDK_Inconsistent: this is the template parameter for which
138  ///   two different template argument values were deduced.
139  TemplateParameter Param;
140
141  /// \brief The first template argument to which the template
142  /// argument deduction failure refers.
143  ///
144  /// Depending on the result of the template argument deduction,
145  /// this template argument may have different meanings:
146  ///
147  ///   TDK_Inconsistent: this argument is the first value deduced
148  ///   for the corresponding template parameter.
149  ///
150  ///   TDK_SubstitutionFailure: this argument is the template
151  ///   argument we were instantiating when we encountered an error.
152  ///
153  ///   TDK_NonDeducedMismatch: this is the template argument
154  ///   provided in the source code.
155  TemplateArgument FirstArg;
156
157  /// \brief The second template argument to which the template
158  /// argument deduction failure refers.
159  ///
160  /// FIXME: Finish documenting this.
161  TemplateArgument SecondArg;
162};
163
164}
165}
166
167#endif
168