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Diffstat (limited to 'include/clang/Lex/Lexer.h')
| -rw-r--r-- | include/clang/Lex/Lexer.h | 353 |
1 files changed, 353 insertions, 0 deletions
diff --git a/include/clang/Lex/Lexer.h b/include/clang/Lex/Lexer.h new file mode 100644 index 0000000000..db0c7183d2 --- /dev/null +++ b/include/clang/Lex/Lexer.h @@ -0,0 +1,353 @@ +//===--- Lexer.h - C Language Family Lexer ----------------------*- C++ -*-===// +// +// The LLVM Compiler Infrastructure +// +// This file was developed by Chris Lattner and 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/LexerToken.h" +#include "clang/Lex/MultipleIncludeOpt.h" +#include "clang/Basic/LangOptions.h" +#include <string> +#include <vector> + +namespace llvm { + class MemoryBuffer; +} + +namespace clang { +class Diagnostic; +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 * const BufferEnd; // End of the buffer. + const llvm::MemoryBuffer *InputFile; // The file we are reading from. + unsigned CurFileID; // FileID for the current input file. + Preprocessor &PP; // Preprocessor object controlling lexing. + LangOptions Features; // Features enabled by this language (cache). + bool Is_PragmaLexer; // True if lexer for _Pragma handling. + bool IsMainFile; // True if top-level file. + + //===--------------------------------------------------------------------===// + // 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. + 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; + + 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 specified MemoryBuffer and Preprocessor objects will + /// outlive it, but doesn't take ownership of either pointer. + Lexer(const llvm::MemoryBuffer *InBuffer, unsigned CurFileID, + Preprocessor &PP, const char *BufStart = 0, const char *BufEnd = 0); + + /// getFeatures - Return the language features currently enabled. NOTE: this + /// lexer modifies features as a file is parsed! + const LangOptions &getFeatures() const { return Features; } + + /// getCurFileID - Return the FileID for the file we are lexing out of. This + /// implicitly encodes the include path to get to the file. + unsigned getCurFileID() const { return CurFileID; } + + /// setIsMainFile - Mark this lexer as being the lexer for the top-level + /// source file. + void setIsMainFile() { + IsMainFile = true; + } + + /// isMainFile - Return true if this is the top-level file. + /// + bool isMainFile() const { return IsMainFile; } + + /// 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(LexerToken &Result) { + // Start a new token. + Result.startToken(); + + // NOTE, any changes here should also change code after calls to + // Preprocessor::HandleDirective + if (IsAtStartOfLine) { + Result.setFlag(LexerToken::StartOfLine); + IsAtStartOfLine = false; + } + + // Get a token. Note that this may delete the current lexer if the end of + // file is reached. + LexTokenInternal(Result); + } + + /// LexRawToken - Switch the lexer to raw mode, lex a token into Result and + /// switch it back. Return true if the 'next character to read' pointer + /// points and the end of the lexer buffer, false otherwise. + bool LexRawToken(LexerToken &Result) { + assert(!LexingRawMode && "Already in raw mode!"); + LexingRawMode = true; + Lex(Result); + LexingRawMode = false; + return BufferPtr == BufferEnd; + } + + /// 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); + + //===--------------------------------------------------------------------===// + // Internal implementation interfaces. +private: + + /// LexTokenInternal - Internal interface to lex a preprocessing token. Called + /// by Lex. + /// + void LexTokenInternal(LexerToken &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(LexerToken &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. + + // 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. + + + /// 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, LexerToken &Tok) { + // If this is not a trigraph and not a UCN or escaped newline, return + // quickly. + if (Ptr[0] != '?' && Ptr[0] != '\\') return *Ptr++; + + unsigned Size = 0; + char C = getCharAndSizeSlow(Ptr, Size, &Tok); + Ptr += Size; + return C; + } + + /// 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, LexerToken &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 (Ptr[0] != '?' && 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, LexerToken *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 (Ptr[0] != '?' && 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 (LexerToken &Result, const char *CurPtr); + void LexNumericConstant (LexerToken &Result, const char *CurPtr); + void LexStringLiteral (LexerToken &Result, const char *CurPtr,bool Wide); + void LexAngledStringLiteral(LexerToken &Result, const char *CurPtr); + void LexCharConstant (LexerToken &Result, const char *CurPtr); + bool LexEndOfFile (LexerToken &Result, const char *CurPtr); + + void SkipWhitespace (LexerToken &Result, const char *CurPtr); + bool SkipBCPLComment (LexerToken &Result, const char *CurPtr); + bool SkipBlockComment (LexerToken &Result, const char *CurPtr); + bool SaveBCPLComment (LexerToken &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(LexerToken &Result); +}; + + +} // end namespace clang + +#endif |