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1//===- PreprocessorLexer.h - C Language Family Lexer ------------*- C++ -*-===//
2//
3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4// See https://llvm.org/LICENSE.txt for license information.
5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6//
7//===----------------------------------------------------------------------===//
8//
9/// \file
10/// Defines the PreprocessorLexer interface.
11//
12//===----------------------------------------------------------------------===//
13
14#ifndef LLVM_CLANG_LEX_PREPROCESSORLEXER_H
15#define LLVM_CLANG_LEX_PREPROCESSORLEXER_H
16
17#include "clang/Basic/FileEntry.h"
18#include "clang/Basic/SourceLocation.h"
19#include "clang/Lex/MultipleIncludeOpt.h"
20#include "clang/Lex/Token.h"
21#include "llvm/ADT/ArrayRef.h"
22#include "llvm/ADT/SmallVector.h"
23#include <cassert>
24
25namespace clang {
26
27class FileEntry;
28class Preprocessor;
29
30class PreprocessorLexer {
31 virtual void anchor();
32
33protected:
34 friend class Preprocessor;
35
36 // Preprocessor object controlling lexing.
37 Preprocessor *PP = nullptr;
38
39 /// The SourceManager FileID corresponding to the file being lexed.
40 const FileID FID;
41
42 /// Number of SLocEntries before lexing the file.
43 unsigned InitialNumSLocEntries = 0;
44
45 //===--------------------------------------------------------------------===//
46 // Context-specific lexing flags set by the preprocessor.
47 //===--------------------------------------------------------------------===//
48
49 /// True when parsing \#XXX; turns '\\n' into a tok::eod token.
50 bool ParsingPreprocessorDirective = false;
51
52 /// True after \#include; turns \<xx> or "xxx" into a tok::header_name token.
53 bool ParsingFilename = false;
54
55 /// True if in raw mode.
56 ///
57 /// Raw mode disables interpretation of tokens and is a far faster mode to
58 /// lex in than non-raw-mode. This flag:
59 /// 1. If EOF of the current lexer is found, the include stack isn't popped.
60 /// 2. Identifier information is not looked up for identifier tokens. As an
61 /// effect of this, implicit macro expansion is naturally disabled.
62 /// 3. "#" tokens at the start of a line are treated as normal tokens, not
63 /// implicitly transformed by the lexer.
64 /// 4. All diagnostic messages are disabled.
65 /// 5. No callbacks are made into the preprocessor.
66 ///
67 /// Note that in raw mode that the PP pointer may be null.
68 bool LexingRawMode = false;
69
70 /// A state machine that detects the \#ifndef-wrapping a file
71 /// idiom for the multiple-include optimization.
72 MultipleIncludeOpt MIOpt;
73
74 /// Information about the set of \#if/\#ifdef/\#ifndef blocks
75 /// we are currently in.
76 SmallVector<PPConditionalInfo, 4> ConditionalStack;
77
78 PreprocessorLexer() : FID() {}
79 PreprocessorLexer(Preprocessor *pp, FileID fid);
80 virtual ~PreprocessorLexer() = default;
81
82 virtual void IndirectLex(Token& Result) = 0;
83
84 /// Return the source location for the next observable location.
85 virtual SourceLocation getSourceLocation() = 0;
86
87 //===--------------------------------------------------------------------===//
88 // #if directive handling.
89
90 /// pushConditionalLevel - When we enter a \#if directive, this keeps track of
91 /// what we are currently in for diagnostic emission (e.g. \#if with missing
92 /// \#endif).
93 void pushConditionalLevel(SourceLocation DirectiveStart, bool WasSkipping,
94 bool FoundNonSkip, bool FoundElse) {
95 PPConditionalInfo CI;
96 CI.IfLoc = DirectiveStart;
97 CI.WasSkipping = WasSkipping;
98 CI.FoundNonSkip = FoundNonSkip;
99 CI.FoundElse = FoundElse;
100 ConditionalStack.push_back(CI);
101 }
102 void pushConditionalLevel(const PPConditionalInfo &CI) {
103 ConditionalStack.push_back(CI);
104 }
105
106 /// popConditionalLevel - Remove an entry off the top of the conditional
107 /// stack, returning information about it. If the conditional stack is empty,
108 /// this returns true and does not fill in the arguments.
109 bool popConditionalLevel(PPConditionalInfo &CI) {
110 if (ConditionalStack.empty())
111 return true;
112 CI = ConditionalStack.pop_back_val();
113 return false;
114 }
115
116 /// Return the top of the conditional stack.
117 /// \pre This requires that there be a conditional active.
118 PPConditionalInfo &peekConditionalLevel() {
119 assert(!ConditionalStack.empty() && "No conditionals active!");
120 return ConditionalStack.back();
121 }
122
123 unsigned getConditionalStackDepth() const { return ConditionalStack.size(); }
124
125public:
126 PreprocessorLexer(const PreprocessorLexer &) = delete;
127 PreprocessorLexer &operator=(const PreprocessorLexer &) = delete;
128
129 //===--------------------------------------------------------------------===//
130 // Misc. lexing methods.
131
132 /// Lex a token, producing a header-name token if possible.
133 void LexIncludeFilename(Token &FilenameTok);
134
135 /// Inform the lexer whether or not we are currently lexing a
136 /// preprocessor directive.
137 void setParsingPreprocessorDirective(bool f) {
138 ParsingPreprocessorDirective = f;
139 }
140
141 /// Return true if this lexer is in raw mode or not.
142 bool isLexingRawMode() const { return LexingRawMode; }
143
144 /// Return the preprocessor object for this lexer.
145 Preprocessor *getPP() const { return PP; }
146
147 FileID getFileID() const {
148 assert(PP &&
149 "PreprocessorLexer::getFileID() should only be used with a Preprocessor");
150 return FID;
151 }
152
153 /// Number of SLocEntries before lexing the file.
154 unsigned getInitialNumSLocEntries() const {
155 return InitialNumSLocEntries;
156 }
157
158 /// getFileEntry - Return the FileEntry corresponding to this FileID. Like
159 /// getFileID(), this only works for lexers with attached preprocessors.
160 OptionalFileEntryRefDegradesToFileEntryPtr getFileEntry() const;
161
162 /// Iterator that traverses the current stack of preprocessor
163 /// conditional directives (\#if/\#ifdef/\#ifndef).
164 using conditional_iterator =
165 SmallVectorImpl<PPConditionalInfo>::const_iterator;
166
167 conditional_iterator conditional_begin() const {
168 return ConditionalStack.begin();
169 }
170
171 conditional_iterator conditional_end() const {
172 return ConditionalStack.end();
173 }
174
175 void setConditionalLevels(ArrayRef<PPConditionalInfo> CL) {
176 ConditionalStack.clear();
177 ConditionalStack.append(CL.begin(), CL.end());
178 }
179};
180
181} // namespace clang
182
183#endif // LLVM_CLANG_LEX_PREPROCESSORLEXER_H
184

Warning: This file is not a C or C++ file. It does not have highlighting.

source code of clang/include/clang/Lex/PreprocessorLexer.h