RAIIObjectsForParser.h revision 28bbe4b8acc338476fe0825769b41fb32b423c72 
1//===--- RAIIObjectsForParser.h - RAII helpers for the parser ---*- 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 defines and implements the some simple RAII objects that are used
11// by the parser to manage bits in recursion.
12//
13//===----------------------------------------------------------------------===//
14
15#ifndef LLVM_CLANG_PARSE_RAII_OBJECTS_FOR_PARSER_H
16#define LLVM_CLANG_PARSE_RAII_OBJECTS_FOR_PARSER_H
17
18#include "clang/Parse/ParseDiagnostic.h"
19
20namespace clang {
21  // TODO: move ParsingDeclRAIIObject here.
22  // TODO: move ParsingClassDefinition here.
23  // TODO: move TentativeParsingAction here.
24
25
26  /// ExtensionRAIIObject - This saves the state of extension warnings when
27  /// constructed and disables them.  When destructed, it restores them back to
28  /// the way they used to be.  This is used to handle __extension__ in the
29  /// parser.
30  class ExtensionRAIIObject {
31    void operator=(const ExtensionRAIIObject &);     // DO NOT IMPLEMENT
32    ExtensionRAIIObject(const ExtensionRAIIObject&); // DO NOT IMPLEMENT
33    Diagnostic &Diags;
34  public:
35    ExtensionRAIIObject(Diagnostic &diags) : Diags(diags) {
36      Diags.IncrementAllExtensionsSilenced();
37    }
38
39    ~ExtensionRAIIObject() {
40      Diags.DecrementAllExtensionsSilenced();
41    }
42  };
43
44  /// ColonProtectionRAIIObject - This sets the Parser::ColonIsSacred bool and
45  /// restores it when destroyed.  This says that "foo:" should not be
46  /// considered a possible typo for "foo::" for error recovery purposes.
47  class ColonProtectionRAIIObject {
48    Parser &P;
49    bool OldVal;
50  public:
51    ColonProtectionRAIIObject(Parser &p, bool Value = true)
52      : P(p), OldVal(P.ColonIsSacred) {
53      P.ColonIsSacred = Value;
54    }
55
56    /// restore - This can be used to restore the state early, before the dtor
57    /// is run.
58    void restore() {
59      P.ColonIsSacred = OldVal;
60    }
61
62    ~ColonProtectionRAIIObject() {
63      restore();
64    }
65  };
66
67  /// \brief RAII object that makes '>' behave either as an operator
68  /// or as the closing angle bracket for a template argument list.
69  class GreaterThanIsOperatorScope {
70    bool &GreaterThanIsOperator;
71    bool OldGreaterThanIsOperator;
72  public:
73    GreaterThanIsOperatorScope(bool &GTIO, bool Val)
74    : GreaterThanIsOperator(GTIO), OldGreaterThanIsOperator(GTIO) {
75      GreaterThanIsOperator = Val;
76    }
77
78    ~GreaterThanIsOperatorScope() {
79      GreaterThanIsOperator = OldGreaterThanIsOperator;
80    }
81  };
82
83  class InMessageExpressionRAIIObject {
84    bool &InMessageExpression;
85    bool OldValue;
86
87  public:
88    InMessageExpressionRAIIObject(Parser &P, bool Value)
89      : InMessageExpression(P.InMessageExpression),
90        OldValue(P.InMessageExpression) {
91      InMessageExpression = Value;
92    }
93
94    ~InMessageExpressionRAIIObject() {
95      InMessageExpression = OldValue;
96    }
97  };
98
99  /// \brief RAII object that makes sure paren/bracket/brace count is correct
100  /// after declaration/statement parsing, even when there's a parsing error.
101  class ParenBraceBracketBalancer {
102    Parser &P;
103    unsigned short ParenCount, BracketCount, BraceCount;
104  public:
105    ParenBraceBracketBalancer(Parser &p)
106      : P(p), ParenCount(p.ParenCount), BracketCount(p.BracketCount),
107        BraceCount(p.BraceCount) { }
108
109    ~ParenBraceBracketBalancer() {
110      P.ParenCount = ParenCount;
111      P.BracketCount = BracketCount;
112      P.BraceCount = BraceCount;
113    }
114  };
115
116  class PoisonSEHIdentifiersRAIIObject {
117    PoisonIdentifierRAIIObject Ident_AbnormalTermination;
118    PoisonIdentifierRAIIObject Ident_GetExceptionCode;
119    PoisonIdentifierRAIIObject Ident_GetExceptionInfo;
120    PoisonIdentifierRAIIObject Ident__abnormal_termination;
121    PoisonIdentifierRAIIObject Ident__exception_code;
122    PoisonIdentifierRAIIObject Ident__exception_info;
123    PoisonIdentifierRAIIObject Ident___abnormal_termination;
124    PoisonIdentifierRAIIObject Ident___exception_code;
125    PoisonIdentifierRAIIObject Ident___exception_info;
126  public:
127    PoisonSEHIdentifiersRAIIObject(Parser &Self, bool NewValue)
128      : Ident_AbnormalTermination(Self.Ident_AbnormalTermination, NewValue),
129        Ident_GetExceptionCode(Self.Ident_GetExceptionCode, NewValue),
130        Ident_GetExceptionInfo(Self.Ident_GetExceptionInfo, NewValue),
131        Ident__abnormal_termination(Self.Ident__abnormal_termination, NewValue),
132        Ident__exception_code(Self.Ident__exception_code, NewValue),
133        Ident__exception_info(Self.Ident__exception_info, NewValue),
134        Ident___abnormal_termination(Self.Ident___abnormal_termination, NewValue),
135        Ident___exception_code(Self.Ident___exception_code, NewValue),
136        Ident___exception_info(Self.Ident___exception_info, NewValue) {
137    }
138  };
139
140} // end namespace clang
141
142#endif
143