1 //===--- PreprocessorLexer.h - C Language Family Lexer ----------*- C++ -*-===//
3 // The LLVM Compiler Infrastructure
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
11 /// \brief Defines the PreprocessorLexer interface.
13 //===----------------------------------------------------------------------===//
15 #ifndef LLVM_CLANG_LEX_PREPROCESSORLEXER_H
16 #define LLVM_CLANG_LEX_PREPROCESSORLEXER_H
18 #include "clang/Lex/MultipleIncludeOpt.h"
19 #include "clang/Lex/Token.h"
20 #include "llvm/ADT/SmallVector.h"
27 class PreprocessorLexer {
28 virtual void anchor();
30 Preprocessor *PP; // Preprocessor object controlling lexing.
32 /// The SourceManager FileID corresponding to the file being lexed.
35 /// \brief Number of SLocEntries before lexing the file.
36 unsigned InitialNumSLocEntries;
38 //===--------------------------------------------------------------------===//
39 // Context-specific lexing flags set by the preprocessor.
40 //===--------------------------------------------------------------------===//
42 /// \brief True when parsing \#XXX; turns '\\n' into a tok::eod token.
43 bool ParsingPreprocessorDirective;
45 /// \brief True after \#include; turns \<xx> into a tok::angle_string_literal
49 /// \brief True if in raw mode.
51 /// Raw mode disables interpretation of tokens and is a far faster mode to
52 /// lex in than non-raw-mode. This flag:
53 /// 1. If EOF of the current lexer is found, the include stack isn't popped.
54 /// 2. Identifier information is not looked up for identifier tokens. As an
55 /// effect of this, implicit macro expansion is naturally disabled.
56 /// 3. "#" tokens at the start of a line are treated as normal tokens, not
57 /// implicitly transformed by the lexer.
58 /// 4. All diagnostic messages are disabled.
59 /// 5. No callbacks are made into the preprocessor.
61 /// Note that in raw mode that the PP pointer may be null.
64 /// \brief A state machine that detects the \#ifndef-wrapping a file
65 /// idiom for the multiple-include optimization.
66 MultipleIncludeOpt MIOpt;
68 /// \brief Information about the set of \#if/\#ifdef/\#ifndef blocks
69 /// we are currently in.
70 SmallVector<PPConditionalInfo, 4> ConditionalStack;
72 PreprocessorLexer(const PreprocessorLexer &) = delete;
73 void operator=(const PreprocessorLexer &) = delete;
74 friend class Preprocessor;
76 PreprocessorLexer(Preprocessor *pp, FileID fid);
79 : PP(nullptr), InitialNumSLocEntries(0),
80 ParsingPreprocessorDirective(false),
81 ParsingFilename(false),
82 LexingRawMode(false) {}
84 virtual ~PreprocessorLexer() {}
86 virtual void IndirectLex(Token& Result) = 0;
88 /// \brief Return the source location for the next observable location.
89 virtual SourceLocation getSourceLocation() = 0;
91 //===--------------------------------------------------------------------===//
92 // #if directive handling.
94 /// pushConditionalLevel - When we enter a \#if directive, this keeps track of
95 /// what we are currently in for diagnostic emission (e.g. \#if with missing
97 void pushConditionalLevel(SourceLocation DirectiveStart, bool WasSkipping,
98 bool FoundNonSkip, bool FoundElse) {
100 CI.IfLoc = DirectiveStart;
101 CI.WasSkipping = WasSkipping;
102 CI.FoundNonSkip = FoundNonSkip;
103 CI.FoundElse = FoundElse;
104 ConditionalStack.push_back(CI);
106 void pushConditionalLevel(const PPConditionalInfo &CI) {
107 ConditionalStack.push_back(CI);
110 /// popConditionalLevel - Remove an entry off the top of the conditional
111 /// stack, returning information about it. If the conditional stack is empty,
112 /// this returns true and does not fill in the arguments.
113 bool popConditionalLevel(PPConditionalInfo &CI) {
114 if (ConditionalStack.empty())
116 CI = ConditionalStack.pop_back_val();
120 /// \brief Return the top of the conditional stack.
121 /// \pre This requires that there be a conditional active.
122 PPConditionalInfo &peekConditionalLevel() {
123 assert(!ConditionalStack.empty() && "No conditionals active!");
124 return ConditionalStack.back();
127 unsigned getConditionalStackDepth() const { return ConditionalStack.size(); }
131 //===--------------------------------------------------------------------===//
132 // Misc. lexing methods.
134 /// \brief After the preprocessor has parsed a \#include, lex and
135 /// (potentially) macro expand the filename.
137 /// If the sequence parsed is not lexically legal, emit a diagnostic and
138 /// return a result EOD token.
139 void LexIncludeFilename(Token &Result);
141 /// \brief Inform the lexer whether or not we are currently lexing a
142 /// preprocessor directive.
143 void setParsingPreprocessorDirective(bool f) {
144 ParsingPreprocessorDirective = f;
147 /// \brief Return true if this lexer is in raw mode or not.
148 bool isLexingRawMode() const { return LexingRawMode; }
150 /// \brief Return the preprocessor object for this lexer.
151 Preprocessor *getPP() const { return PP; }
153 FileID getFileID() const {
155 "PreprocessorLexer::getFileID() should only be used with a Preprocessor");
159 /// \brief Number of SLocEntries before lexing the file.
160 unsigned getInitialNumSLocEntries() const {
161 return InitialNumSLocEntries;
164 /// getFileEntry - Return the FileEntry corresponding to this FileID. Like
165 /// getFileID(), this only works for lexers with attached preprocessors.
166 const FileEntry *getFileEntry() const;
168 /// \brief Iterator that traverses the current stack of preprocessor
169 /// conditional directives (\#if/\#ifdef/\#ifndef).
170 typedef SmallVectorImpl<PPConditionalInfo>::const_iterator
171 conditional_iterator;
173 conditional_iterator conditional_begin() const {
174 return ConditionalStack.begin();
176 conditional_iterator conditional_end() const {
177 return ConditionalStack.end();
181 } // end namespace clang