| //===--- Lexer.h - C Language Family Lexer ----------------------*- C++ -*-===// |
| // |
| // The LLVM Compiler Infrastructure |
| // |
| // This file is distributed under the University of Illinois Open Source |
| // License. See LICENSE.TXT for details. |
| // |
| //===----------------------------------------------------------------------===// |
| // |
| // This file defines the Lexer interface. |
| // |
| //===----------------------------------------------------------------------===// |
| |
| #ifndef LLVM_CLANG_LEXER_H |
| #define LLVM_CLANG_LEXER_H |
| |
| #include "clang/Lex/Token.h" |
| #include "clang/Lex/MultipleIncludeOpt.h" |
| #include "clang/Basic/LangOptions.h" |
| #include "llvm/ADT/SmallVector.h" |
| #include <string> |
| #include <vector> |
| #include <cassert> |
| |
| namespace clang { |
| class Diagnostic; |
| class SourceManager; |
| class Preprocessor; |
| |
| /// Lexer - This provides a simple interface that turns a text buffer into a |
| /// stream of tokens. This provides no support for file reading or buffering, |
| /// or buffering/seeking of tokens, only forward lexing is supported. It relies |
| /// on the specified Preprocessor object to handle preprocessor directives, etc. |
| class Lexer { |
| //===--------------------------------------------------------------------===// |
| // Constant configuration values for this lexer. |
| const char *BufferStart; // Start of the buffer. |
| const char *BufferEnd; // End of the buffer. |
| SourceLocation FileLoc; // Location for start of file. |
| Preprocessor *PP; // Preprocessor object controlling lexing. |
| LangOptions Features; // Features enabled by this language (cache). |
| bool Is_PragmaLexer; // True if lexer for _Pragma handling. |
| |
| //===--------------------------------------------------------------------===// |
| // Context-specific lexing flags set by the preprocessor. |
| // |
| |
| /// ParsingPreprocessorDirective - This is true when parsing #XXX. This turns |
| /// '\n' into a tok::eom token. |
| bool ParsingPreprocessorDirective; |
| |
| /// ParsingFilename - True after #include: this turns <xx> into a |
| /// tok::angle_string_literal token. |
| bool ParsingFilename; |
| |
| /// LexingRawMode - True if in raw mode: This flag disables interpretation of |
| /// tokens and is a far faster mode to lex in than non-raw-mode. This flag: |
| /// 1. If EOF of the current lexer is found, the include stack isn't popped. |
| /// 2. Identifier information is not looked up for identifier tokens. As an |
| /// effect of this, implicit macro expansion is naturally disabled. |
| /// 3. "#" tokens at the start of a line are treated as normal tokens, not |
| /// implicitly transformed by the lexer. |
| /// 4. All diagnostic messages are disabled, except for unterminated /*. |
| /// 5. The only callback made into the preprocessor is to report a hard error |
| /// on an unterminated '/*' comment. |
| /// |
| /// Note that in raw mode that the PP pointer may be null. |
| bool LexingRawMode; |
| |
| /// KeepCommentMode - The lexer can optionally keep C & BCPL-style comments, |
| /// and return them as tokens. This is used for -C and -CC modes. |
| bool KeepCommentMode; |
| |
| //===--------------------------------------------------------------------===// |
| // Context that changes as the file is lexed. |
| // NOTE: any state that mutates when in raw mode must have save/restore code |
| // in Lexer::isNextPPTokenLParen. |
| |
| // BufferPtr - Current pointer into the buffer. This is the next character |
| // to be lexed. |
| const char *BufferPtr; |
| |
| // IsAtStartOfLine - True if the next lexed token should get the "start of |
| // line" flag set on it. |
| bool IsAtStartOfLine; |
| |
| /// MIOpt - This is a state machine that detects the #ifndef-wrapping a file |
| /// idiom for the multiple-include optimization. |
| MultipleIncludeOpt MIOpt; |
| |
| /// ConditionalStack - Information about the set of #if/#ifdef/#ifndef blocks |
| /// we are currently in. |
| std::vector<PPConditionalInfo> ConditionalStack; |
| |
| Lexer(const Lexer&); // DO NOT IMPLEMENT |
| void operator=(const Lexer&); // DO NOT IMPLEMENT |
| friend class Preprocessor; |
| public: |
| |
| /// Lexer constructor - Create a new lexer object for the specified buffer |
| /// with the specified preprocessor managing the lexing process. This lexer |
| /// assumes that the associated file buffer and Preprocessor objects will |
| /// outlive it, so it doesn't take ownership of either of them. |
| Lexer(SourceLocation FileLoc, Preprocessor &PP, |
| const char *BufStart = 0, const char *BufEnd = 0); |
| |
| /// Lexer constructor - Create a new raw lexer object. This object is only |
| /// suitable for calls to 'LexRawToken'. This lexer assumes that the text |
| /// range will outlive it, so it doesn't take ownership of it. |
| Lexer(SourceLocation FileLoc, const LangOptions &Features, |
| const char *BufStart, const char *BufEnd, |
| const llvm::MemoryBuffer *FromFile = 0); |
| |
| /// getFeatures - Return the language features currently enabled. NOTE: this |
| /// lexer modifies features as a file is parsed! |
| const LangOptions &getFeatures() const { return Features; } |
| |
| /// getFileLoc - Return the File Location for the file we are lexing out of. |
| /// The physical location encodes the location where the characters come from, |
| /// the virtual location encodes where we should *claim* the characters came |
| /// from. Currently this is only used by _Pragma handling. |
| SourceLocation getFileLoc() const { return FileLoc; } |
| |
| /// Lex - Return the next token in the file. If this is the end of file, it |
| /// return the tok::eof token. Return true if an error occurred and |
| /// compilation should terminate, false if normal. This implicitly involves |
| /// the preprocessor. |
| void Lex(Token &Result) { |
| // Start a new token. |
| Result.startToken(); |
| |
| // NOTE, any changes here should also change code after calls to |
| // Preprocessor::HandleDirective |
| if (IsAtStartOfLine) { |
| Result.setFlag(Token::StartOfLine); |
| IsAtStartOfLine = false; |
| } |
| |
| // Get a token. Note that this may delete the current lexer if the end of |
| // file is reached. |
| LexTokenInternal(Result); |
| } |
| |
| /// LexFromRawLexer - Lex a token from a designated raw lexer (one with no |
| /// associated preprocessor object. Return true if the 'next character to |
| /// read' pointer points and the end of the lexer buffer, false otherwise. |
| bool LexFromRawLexer(Token &Result) { |
| assert(LexingRawMode && "Not already in raw mode!"); |
| Lex(Result); |
| // Note that lexing to the end of the buffer doesn't implicitly delete the |
| // lexer when in raw mode. |
| return BufferPtr == BufferEnd; |
| } |
| |
| /// SetCommentRetentionMode - Change the comment retention mode of the lexer |
| /// to the specified mode. This is really only useful when lexing in raw |
| /// mode, because otherwise the lexer needs to manage this. |
| void SetCommentRetentionState(bool Mode) { |
| KeepCommentMode = Mode; |
| } |
| |
| /// ReadToEndOfLine - Read the rest of the current preprocessor line as an |
| /// uninterpreted string. This switches the lexer out of directive mode. |
| std::string ReadToEndOfLine(); |
| |
| |
| /// Diag - Forwarding function for diagnostics. This translate a source |
| /// position in the current buffer into a SourceLocation object for rendering. |
| void Diag(const char *Loc, unsigned DiagID, |
| const std::string &Msg = std::string()) const; |
| void Diag(SourceLocation Loc, unsigned DiagID, |
| const std::string &Msg = std::string()) const; |
| |
| /// getSourceLocation - Return a source location identifier for the specified |
| /// offset in the current file. |
| SourceLocation getSourceLocation(const char *Loc) const; |
| |
| /// Stringify - Convert the specified string into a C string by escaping '\' |
| /// and " characters. This does not add surrounding ""'s to the string. |
| /// If Charify is true, this escapes the ' character instead of ". |
| static std::string Stringify(const std::string &Str, bool Charify = false); |
| |
| /// Stringify - Convert the specified string into a C string by escaping '\' |
| /// and " characters. This does not add surrounding ""'s to the string. |
| static void Stringify(llvm::SmallVectorImpl<char> &Str); |
| |
| /// MeasureTokenLength - Relex the token at the specified location and return |
| /// its length in bytes in the input file. If the token needs cleaning (e.g. |
| /// includes a trigraph or an escaped newline) then this count includes bytes |
| /// that are part of that. |
| static unsigned MeasureTokenLength(SourceLocation Loc, |
| const SourceManager &SM); |
| |
| //===--------------------------------------------------------------------===// |
| // Internal implementation interfaces. |
| private: |
| |
| /// LexTokenInternal - Internal interface to lex a preprocessing token. Called |
| /// by Lex. |
| /// |
| void LexTokenInternal(Token &Result); |
| |
| /// FormTokenWithChars - When we lex a token, we have identified a span |
| /// starting at BufferPtr, going to TokEnd that forms the token. This method |
| /// takes that range and assigns it to the token as its location and size. In |
| /// addition, since tokens cannot overlap, this also updates BufferPtr to be |
| /// TokEnd. |
| void FormTokenWithChars(Token &Result, const char *TokEnd) { |
| Result.setLocation(getSourceLocation(BufferPtr)); |
| Result.setLength(TokEnd-BufferPtr); |
| BufferPtr = TokEnd; |
| } |
| |
| /// isNextPPTokenLParen - Return 1 if the next unexpanded token will return a |
| /// tok::l_paren token, 0 if it is something else and 2 if there are no more |
| /// tokens in the buffer controlled by this lexer. |
| unsigned isNextPPTokenLParen(); |
| |
| //===--------------------------------------------------------------------===// |
| // Lexer character reading interfaces. |
| public: |
| |
| // This lexer is built on two interfaces for reading characters, both of which |
| // automatically provide phase 1/2 translation. getAndAdvanceChar is used |
| // when we know that we will be reading a character from the input buffer and |
| // that this character will be part of the result token. This occurs in (f.e.) |
| // string processing, because we know we need to read until we find the |
| // closing '"' character. |
| // |
| // The second interface is the combination of PeekCharAndSize with |
| // ConsumeChar. PeekCharAndSize reads a phase 1/2 translated character, |
| // returning it and its size. If the lexer decides that this character is |
| // part of the current token, it calls ConsumeChar on it. This two stage |
| // approach allows us to emit diagnostics for characters (e.g. warnings about |
| // trigraphs), knowing that they only are emitted if the character is |
| // consumed. |
| |
| /// isObviouslySimpleCharacter - Return true if the specified character is |
| /// obviously the same in translation phase 1 and translation phase 3. This |
| /// can return false for characters that end up being the same, but it will |
| /// never return true for something that needs to be mapped. |
| static bool isObviouslySimpleCharacter(char C) { |
| return C != '?' && C != '\\'; |
| } |
| |
| /// getAndAdvanceChar - Read a single 'character' from the specified buffer, |
| /// advance over it, and return it. This is tricky in several cases. Here we |
| /// just handle the trivial case and fall-back to the non-inlined |
| /// getCharAndSizeSlow method to handle the hard case. |
| inline char getAndAdvanceChar(const char *&Ptr, Token &Tok) { |
| // If this is not a trigraph and not a UCN or escaped newline, return |
| // quickly. |
| if (isObviouslySimpleCharacter(Ptr[0])) return *Ptr++; |
| |
| unsigned Size = 0; |
| char C = getCharAndSizeSlow(Ptr, Size, &Tok); |
| Ptr += Size; |
| return C; |
| } |
| |
| private: |
| /// ConsumeChar - When a character (identified by PeekCharAndSize) is consumed |
| /// and added to a given token, check to see if there are diagnostics that |
| /// need to be emitted or flags that need to be set on the token. If so, do |
| /// it. |
| const char *ConsumeChar(const char *Ptr, unsigned Size, Token &Tok) { |
| // Normal case, we consumed exactly one token. Just return it. |
| if (Size == 1) |
| return Ptr+Size; |
| |
| // Otherwise, re-lex the character with a current token, allowing |
| // diagnostics to be emitted and flags to be set. |
| Size = 0; |
| getCharAndSizeSlow(Ptr, Size, &Tok); |
| return Ptr+Size; |
| } |
| |
| /// getCharAndSize - Peek a single 'character' from the specified buffer, |
| /// get its size, and return it. This is tricky in several cases. Here we |
| /// just handle the trivial case and fall-back to the non-inlined |
| /// getCharAndSizeSlow method to handle the hard case. |
| inline char getCharAndSize(const char *Ptr, unsigned &Size) { |
| // If this is not a trigraph and not a UCN or escaped newline, return |
| // quickly. |
| if (isObviouslySimpleCharacter(Ptr[0])) { |
| Size = 1; |
| return *Ptr; |
| } |
| |
| Size = 0; |
| return getCharAndSizeSlow(Ptr, Size); |
| } |
| |
| /// getCharAndSizeSlow - Handle the slow/uncommon case of the getCharAndSize |
| /// method. |
| char getCharAndSizeSlow(const char *Ptr, unsigned &Size, Token *Tok = 0); |
| |
| /// getCharAndSizeNoWarn - Like the getCharAndSize method, but does not ever |
| /// emit a warning. |
| static inline char getCharAndSizeNoWarn(const char *Ptr, unsigned &Size, |
| const LangOptions &Features) { |
| // If this is not a trigraph and not a UCN or escaped newline, return |
| // quickly. |
| if (isObviouslySimpleCharacter(Ptr[0])) { |
| Size = 1; |
| return *Ptr; |
| } |
| |
| Size = 0; |
| return getCharAndSizeSlowNoWarn(Ptr, Size, Features); |
| } |
| |
| /// getCharAndSizeSlowNoWarn - Same as getCharAndSizeSlow, but never emits a |
| /// diagnostic. |
| static char getCharAndSizeSlowNoWarn(const char *Ptr, unsigned &Size, |
| const LangOptions &Features); |
| |
| //===--------------------------------------------------------------------===// |
| // #if directive handling. |
| |
| /// pushConditionalLevel - When we enter a #if directive, this keeps track of |
| /// what we are currently in for diagnostic emission (e.g. #if with missing |
| /// #endif). |
| void pushConditionalLevel(SourceLocation DirectiveStart, bool WasSkipping, |
| bool FoundNonSkip, bool FoundElse) { |
| PPConditionalInfo CI; |
| CI.IfLoc = DirectiveStart; |
| CI.WasSkipping = WasSkipping; |
| CI.FoundNonSkip = FoundNonSkip; |
| CI.FoundElse = FoundElse; |
| ConditionalStack.push_back(CI); |
| } |
| void pushConditionalLevel(const PPConditionalInfo &CI) { |
| ConditionalStack.push_back(CI); |
| } |
| |
| /// popConditionalLevel - Remove an entry off the top of the conditional |
| /// stack, returning information about it. If the conditional stack is empty, |
| /// this returns true and does not fill in the arguments. |
| bool popConditionalLevel(PPConditionalInfo &CI) { |
| if (ConditionalStack.empty()) return true; |
| CI = ConditionalStack.back(); |
| ConditionalStack.pop_back(); |
| return false; |
| } |
| |
| /// peekConditionalLevel - Return the top of the conditional stack. This |
| /// requires that there be a conditional active. |
| PPConditionalInfo &peekConditionalLevel() { |
| assert(!ConditionalStack.empty() && "No conditionals active!"); |
| return ConditionalStack.back(); |
| } |
| |
| unsigned getConditionalStackDepth() const { return ConditionalStack.size(); } |
| |
| //===--------------------------------------------------------------------===// |
| // Other lexer functions. |
| |
| // Helper functions to lex the remainder of a token of the specific type. |
| void LexIdentifier (Token &Result, const char *CurPtr); |
| void LexNumericConstant (Token &Result, const char *CurPtr); |
| void LexStringLiteral (Token &Result, const char *CurPtr,bool Wide); |
| void LexAngledStringLiteral(Token &Result, const char *CurPtr); |
| void LexCharConstant (Token &Result, const char *CurPtr); |
| bool LexEndOfFile (Token &Result, const char *CurPtr); |
| |
| void SkipWhitespace (Token &Result, const char *CurPtr); |
| bool SkipBCPLComment (Token &Result, const char *CurPtr); |
| bool SkipBlockComment (Token &Result, const char *CurPtr); |
| bool SaveBCPLComment (Token &Result, const char *CurPtr); |
| |
| /// LexIncludeFilename - After the preprocessor has parsed a #include, lex and |
| /// (potentially) macro expand the filename. If the sequence parsed is not |
| /// lexically legal, emit a diagnostic and return a result EOM token. |
| void LexIncludeFilename(Token &Result); |
| }; |
| |
| |
| } // end namespace clang |
| |
| #endif |