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/ArrayRef.h"
21 #include "llvm/ADT/SmallVector.h"
28 class PreprocessorLexer {
29 virtual void anchor();
31 Preprocessor *PP; // Preprocessor object controlling lexing.
33 /// The SourceManager FileID corresponding to the file being lexed.
36 /// \brief Number of SLocEntries before lexing the file.
37 unsigned InitialNumSLocEntries;
39 //===--------------------------------------------------------------------===//
40 // Context-specific lexing flags set by the preprocessor.
41 //===--------------------------------------------------------------------===//
43 /// \brief True when parsing \#XXX; turns '\\n' into a tok::eod token.
44 bool ParsingPreprocessorDirective;
46 /// \brief True after \#include; turns \<xx> into a tok::angle_string_literal
50 /// \brief True if in raw mode.
52 /// Raw mode disables interpretation of tokens and is a far faster mode to
53 /// lex in than non-raw-mode. This flag:
54 /// 1. If EOF of the current lexer is found, the include stack isn't popped.
55 /// 2. Identifier information is not looked up for identifier tokens. As an
56 /// effect of this, implicit macro expansion is naturally disabled.
57 /// 3. "#" tokens at the start of a line are treated as normal tokens, not
58 /// implicitly transformed by the lexer.
59 /// 4. All diagnostic messages are disabled.
60 /// 5. No callbacks are made into the preprocessor.
62 /// Note that in raw mode that the PP pointer may be null.
65 /// \brief A state machine that detects the \#ifndef-wrapping a file
66 /// idiom for the multiple-include optimization.
67 MultipleIncludeOpt MIOpt;
69 /// \brief Information about the set of \#if/\#ifdef/\#ifndef blocks
70 /// we are currently in.
71 SmallVector<PPConditionalInfo, 4> ConditionalStack;
73 PreprocessorLexer(const PreprocessorLexer &) = delete;
74 void operator=(const PreprocessorLexer &) = delete;
75 friend class Preprocessor;
77 PreprocessorLexer(Preprocessor *pp, FileID fid);
80 : PP(nullptr), InitialNumSLocEntries(0),
81 ParsingPreprocessorDirective(false),
82 ParsingFilename(false),
83 LexingRawMode(false) {}
85 virtual ~PreprocessorLexer() {}
87 virtual void IndirectLex(Token& Result) = 0;
89 /// \brief Return the source location for the next observable location.
90 virtual SourceLocation getSourceLocation() = 0;
92 //===--------------------------------------------------------------------===//
93 // #if directive handling.
95 /// pushConditionalLevel - When we enter a \#if directive, this keeps track of
96 /// what we are currently in for diagnostic emission (e.g. \#if with missing
98 void pushConditionalLevel(SourceLocation DirectiveStart, bool WasSkipping,
99 bool FoundNonSkip, bool FoundElse) {
100 PPConditionalInfo CI;
101 CI.IfLoc = DirectiveStart;
102 CI.WasSkipping = WasSkipping;
103 CI.FoundNonSkip = FoundNonSkip;
104 CI.FoundElse = FoundElse;
105 ConditionalStack.push_back(CI);
107 void pushConditionalLevel(const PPConditionalInfo &CI) {
108 ConditionalStack.push_back(CI);
111 /// popConditionalLevel - Remove an entry off the top of the conditional
112 /// stack, returning information about it. If the conditional stack is empty,
113 /// this returns true and does not fill in the arguments.
114 bool popConditionalLevel(PPConditionalInfo &CI) {
115 if (ConditionalStack.empty())
117 CI = ConditionalStack.pop_back_val();
121 /// \brief Return the top of the conditional stack.
122 /// \pre This requires that there be a conditional active.
123 PPConditionalInfo &peekConditionalLevel() {
124 assert(!ConditionalStack.empty() && "No conditionals active!");
125 return ConditionalStack.back();
128 unsigned getConditionalStackDepth() const { return ConditionalStack.size(); }
132 //===--------------------------------------------------------------------===//
133 // Misc. lexing methods.
135 /// \brief After the preprocessor has parsed a \#include, lex and
136 /// (potentially) macro expand the filename.
138 /// If the sequence parsed is not lexically legal, emit a diagnostic and
139 /// return a result EOD token.
140 void LexIncludeFilename(Token &Result);
142 /// \brief Inform the lexer whether or not we are currently lexing a
143 /// preprocessor directive.
144 void setParsingPreprocessorDirective(bool f) {
145 ParsingPreprocessorDirective = f;
148 /// \brief Return true if this lexer is in raw mode or not.
149 bool isLexingRawMode() const { return LexingRawMode; }
151 /// \brief Return the preprocessor object for this lexer.
152 Preprocessor *getPP() const { return PP; }
154 FileID getFileID() const {
156 "PreprocessorLexer::getFileID() should only be used with a Preprocessor");
160 /// \brief Number of SLocEntries before lexing the file.
161 unsigned getInitialNumSLocEntries() const {
162 return InitialNumSLocEntries;
165 /// getFileEntry - Return the FileEntry corresponding to this FileID. Like
166 /// getFileID(), this only works for lexers with attached preprocessors.
167 const FileEntry *getFileEntry() const;
169 /// \brief Iterator that traverses the current stack of preprocessor
170 /// conditional directives (\#if/\#ifdef/\#ifndef).
171 typedef SmallVectorImpl<PPConditionalInfo>::const_iterator
172 conditional_iterator;
174 conditional_iterator conditional_begin() const {
175 return ConditionalStack.begin();
177 conditional_iterator conditional_end() const {
178 return ConditionalStack.end();
181 void setConditionalLevels(ArrayRef<PPConditionalInfo> CL) {
182 ConditionalStack.clear();
183 ConditionalStack.append(CL.begin(), CL.end());
187 } // end namespace clang