382 lines
16 KiB
C++
382 lines
16 KiB
C++
//===--- Lexer.h - C Language Family Lexer ----------------------*- C++ -*-===//
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//
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// The LLVM Compiler Infrastructure
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//
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// This file is distributed under the University of Illinois Open Source
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// License. See LICENSE.TXT for details.
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//
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//===----------------------------------------------------------------------===//
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//
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// This file defines the Lexer interface.
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//
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//===----------------------------------------------------------------------===//
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#ifndef LLVM_CLANG_LEXER_H
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#define LLVM_CLANG_LEXER_H
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#include "clang/Lex/PreprocessorLexer.h"
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#include "clang/Basic/LangOptions.h"
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#include "llvm/ADT/SmallVector.h"
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#include <string>
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#include <vector>
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#include <cassert>
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namespace clang {
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class Diagnostic;
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class SourceManager;
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class Preprocessor;
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class DiagnosticBuilder;
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/// Lexer - This provides a simple interface that turns a text buffer into a
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/// stream of tokens. This provides no support for file reading or buffering,
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/// or buffering/seeking of tokens, only forward lexing is supported. It relies
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/// on the specified Preprocessor object to handle preprocessor directives, etc.
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class Lexer : public PreprocessorLexer {
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//===--------------------------------------------------------------------===//
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// Constant configuration values for this lexer.
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const char *BufferStart; // Start of the buffer.
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const char *BufferEnd; // End of the buffer.
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SourceLocation FileLoc; // Location for start of file.
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LangOptions Features; // Features enabled by this language (cache).
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bool Is_PragmaLexer : 1; // True if lexer for _Pragma handling.
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bool IsInConflictMarker : 1; // True if in a VCS conflict marker '<<<<<<<'
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//===--------------------------------------------------------------------===//
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// Context-specific lexing flags set by the preprocessor.
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//
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/// ExtendedTokenMode - The lexer can optionally keep comments and whitespace
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/// and return them as tokens. This is used for -C and -CC modes, and
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/// whitespace preservation can be useful for some clients that want to lex
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/// the file in raw mode and get every character from the file.
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///
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/// When this is set to 2 it returns comments and whitespace. When set to 1
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/// it returns comments, when it is set to 0 it returns normal tokens only.
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unsigned char ExtendedTokenMode;
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//===--------------------------------------------------------------------===//
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// Context that changes as the file is lexed.
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// NOTE: any state that mutates when in raw mode must have save/restore code
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// in Lexer::isNextPPTokenLParen.
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// BufferPtr - Current pointer into the buffer. This is the next character
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// to be lexed.
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const char *BufferPtr;
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// IsAtStartOfLine - True if the next lexed token should get the "start of
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// line" flag set on it.
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bool IsAtStartOfLine;
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Lexer(const Lexer&); // DO NOT IMPLEMENT
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void operator=(const Lexer&); // DO NOT IMPLEMENT
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friend class Preprocessor;
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void InitLexer(const char *BufStart, const char *BufPtr, const char *BufEnd);
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public:
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/// Lexer constructor - Create a new lexer object for the specified buffer
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/// with the specified preprocessor managing the lexing process. This lexer
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/// assumes that the associated file buffer and Preprocessor objects will
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/// outlive it, so it doesn't take ownership of either of them.
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Lexer(FileID FID, const llvm::MemoryBuffer *InputBuffer, Preprocessor &PP);
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/// Lexer constructor - Create a new raw lexer object. This object is only
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/// suitable for calls to 'LexRawToken'. This lexer assumes that the text
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/// range will outlive it, so it doesn't take ownership of it.
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Lexer(SourceLocation FileLoc, const LangOptions &Features,
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const char *BufStart, const char *BufPtr, const char *BufEnd);
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/// Lexer constructor - Create a new raw lexer object. This object is only
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/// suitable for calls to 'LexRawToken'. This lexer assumes that the text
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/// range will outlive it, so it doesn't take ownership of it.
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Lexer(FileID FID, const llvm::MemoryBuffer *InputBuffer,
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const SourceManager &SM, const LangOptions &Features);
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/// Create_PragmaLexer: Lexer constructor - Create a new lexer object for
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/// _Pragma expansion. This has a variety of magic semantics that this method
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/// sets up. It returns a new'd Lexer that must be delete'd when done.
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static Lexer *Create_PragmaLexer(SourceLocation SpellingLoc,
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SourceLocation InstantiationLocStart,
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SourceLocation InstantiationLocEnd,
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unsigned TokLen, Preprocessor &PP);
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/// getFeatures - Return the language features currently enabled. NOTE: this
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/// lexer modifies features as a file is parsed!
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const LangOptions &getFeatures() const { return Features; }
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/// getFileLoc - Return the File Location for the file we are lexing out of.
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/// The physical location encodes the location where the characters come from,
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/// the virtual location encodes where we should *claim* the characters came
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/// from. Currently this is only used by _Pragma handling.
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SourceLocation getFileLoc() const { return FileLoc; }
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/// Lex - Return the next token in the file. If this is the end of file, it
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/// return the tok::eof token. Return true if an error occurred and
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/// compilation should terminate, false if normal. This implicitly involves
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/// the preprocessor.
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void Lex(Token &Result) {
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// Start a new token.
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Result.startToken();
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// NOTE, any changes here should also change code after calls to
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// Preprocessor::HandleDirective
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if (IsAtStartOfLine) {
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Result.setFlag(Token::StartOfLine);
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IsAtStartOfLine = false;
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}
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// Get a token. Note that this may delete the current lexer if the end of
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// file is reached.
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LexTokenInternal(Result);
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}
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/// isPragmaLexer - Returns true if this Lexer is being used to lex a pragma.
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bool isPragmaLexer() const { return Is_PragmaLexer; }
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/// IndirectLex - An indirect call to 'Lex' that can be invoked via
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/// the PreprocessorLexer interface.
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void IndirectLex(Token &Result) { Lex(Result); }
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/// LexFromRawLexer - Lex a token from a designated raw lexer (one with no
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/// associated preprocessor object. Return true if the 'next character to
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/// read' pointer points at the end of the lexer buffer, false otherwise.
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bool LexFromRawLexer(Token &Result) {
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assert(LexingRawMode && "Not already in raw mode!");
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Lex(Result);
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// Note that lexing to the end of the buffer doesn't implicitly delete the
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// lexer when in raw mode.
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return BufferPtr == BufferEnd;
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}
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/// isKeepWhitespaceMode - Return true if the lexer should return tokens for
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/// every character in the file, including whitespace and comments. This
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/// should only be used in raw mode, as the preprocessor is not prepared to
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/// deal with the excess tokens.
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bool isKeepWhitespaceMode() const {
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return ExtendedTokenMode > 1;
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}
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/// SetKeepWhitespaceMode - This method lets clients enable or disable
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/// whitespace retention mode.
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void SetKeepWhitespaceMode(bool Val) {
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assert((!Val || LexingRawMode) &&
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"Can only enable whitespace retention in raw mode");
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ExtendedTokenMode = Val ? 2 : 0;
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}
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/// inKeepCommentMode - Return true if the lexer should return comments as
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/// tokens.
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bool inKeepCommentMode() const {
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return ExtendedTokenMode > 0;
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}
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/// SetCommentRetentionMode - Change the comment retention mode of the lexer
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/// to the specified mode. This is really only useful when lexing in raw
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/// mode, because otherwise the lexer needs to manage this.
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void SetCommentRetentionState(bool Mode) {
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assert(!isKeepWhitespaceMode() &&
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"Can't play with comment retention state when retaining whitespace");
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ExtendedTokenMode = Mode ? 1 : 0;
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}
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const char *getBufferStart() const { return BufferStart; }
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/// ReadToEndOfLine - Read the rest of the current preprocessor line as an
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/// uninterpreted string. This switches the lexer out of directive mode.
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std::string ReadToEndOfLine();
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/// Diag - Forwarding function for diagnostics. This translate a source
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/// position in the current buffer into a SourceLocation object for rendering.
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DiagnosticBuilder Diag(const char *Loc, unsigned DiagID) const;
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/// getSourceLocation - Return a source location identifier for the specified
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/// offset in the current file.
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SourceLocation getSourceLocation(const char *Loc, unsigned TokLen = 1) const;
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/// getSourceLocation - Return a source location for the next character in
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/// the current file.
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SourceLocation getSourceLocation() { return getSourceLocation(BufferPtr); }
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/// Stringify - Convert the specified string into a C string by escaping '\'
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/// and " characters. This does not add surrounding ""'s to the string.
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/// If Charify is true, this escapes the ' character instead of ".
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static std::string Stringify(const std::string &Str, bool Charify = false);
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/// Stringify - Convert the specified string into a C string by escaping '\'
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/// and " characters. This does not add surrounding ""'s to the string.
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static void Stringify(llvm::SmallVectorImpl<char> &Str);
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/// MeasureTokenLength - Relex the token at the specified location and return
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/// its length in bytes in the input file. If the token needs cleaning (e.g.
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/// includes a trigraph or an escaped newline) then this count includes bytes
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/// that are part of that.
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static unsigned MeasureTokenLength(SourceLocation Loc,
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const SourceManager &SM,
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const LangOptions &LangOpts);
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//===--------------------------------------------------------------------===//
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// Internal implementation interfaces.
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private:
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/// LexTokenInternal - Internal interface to lex a preprocessing token. Called
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/// by Lex.
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///
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void LexTokenInternal(Token &Result);
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/// FormTokenWithChars - When we lex a token, we have identified a span
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/// starting at BufferPtr, going to TokEnd that forms the token. This method
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/// takes that range and assigns it to the token as its location and size. In
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/// addition, since tokens cannot overlap, this also updates BufferPtr to be
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/// TokEnd.
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void FormTokenWithChars(Token &Result, const char *TokEnd,
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tok::TokenKind Kind) {
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unsigned TokLen = TokEnd-BufferPtr;
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Result.setLength(TokLen);
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Result.setLocation(getSourceLocation(BufferPtr, TokLen));
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Result.setKind(Kind);
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BufferPtr = TokEnd;
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}
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/// isNextPPTokenLParen - Return 1 if the next unexpanded token will return a
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/// tok::l_paren token, 0 if it is something else and 2 if there are no more
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/// tokens in the buffer controlled by this lexer.
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unsigned isNextPPTokenLParen();
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//===--------------------------------------------------------------------===//
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// Lexer character reading interfaces.
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public:
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// This lexer is built on two interfaces for reading characters, both of which
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// automatically provide phase 1/2 translation. getAndAdvanceChar is used
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// when we know that we will be reading a character from the input buffer and
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// that this character will be part of the result token. This occurs in (f.e.)
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// string processing, because we know we need to read until we find the
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// closing '"' character.
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//
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// The second interface is the combination of getCharAndSize with
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// ConsumeChar. getCharAndSize reads a phase 1/2 translated character,
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// returning it and its size. If the lexer decides that this character is
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// part of the current token, it calls ConsumeChar on it. This two stage
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// approach allows us to emit diagnostics for characters (e.g. warnings about
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// trigraphs), knowing that they only are emitted if the character is
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// consumed.
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/// isObviouslySimpleCharacter - Return true if the specified character is
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/// obviously the same in translation phase 1 and translation phase 3. This
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/// can return false for characters that end up being the same, but it will
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/// never return true for something that needs to be mapped.
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static bool isObviouslySimpleCharacter(char C) {
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return C != '?' && C != '\\';
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}
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/// getAndAdvanceChar - Read a single 'character' from the specified buffer,
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/// advance over it, and return it. This is tricky in several cases. Here we
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/// just handle the trivial case and fall-back to the non-inlined
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/// getCharAndSizeSlow method to handle the hard case.
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inline char getAndAdvanceChar(const char *&Ptr, Token &Tok) {
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// If this is not a trigraph and not a UCN or escaped newline, return
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// quickly.
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if (isObviouslySimpleCharacter(Ptr[0])) return *Ptr++;
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unsigned Size = 0;
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char C = getCharAndSizeSlow(Ptr, Size, &Tok);
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Ptr += Size;
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return C;
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}
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private:
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/// ConsumeChar - When a character (identified by getCharAndSize) is consumed
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/// and added to a given token, check to see if there are diagnostics that
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/// need to be emitted or flags that need to be set on the token. If so, do
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/// it.
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const char *ConsumeChar(const char *Ptr, unsigned Size, Token &Tok) {
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// Normal case, we consumed exactly one token. Just return it.
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if (Size == 1)
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return Ptr+Size;
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// Otherwise, re-lex the character with a current token, allowing
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// diagnostics to be emitted and flags to be set.
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Size = 0;
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getCharAndSizeSlow(Ptr, Size, &Tok);
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return Ptr+Size;
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}
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/// getCharAndSize - Peek a single 'character' from the specified buffer,
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/// get its size, and return it. This is tricky in several cases. Here we
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/// just handle the trivial case and fall-back to the non-inlined
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/// getCharAndSizeSlow method to handle the hard case.
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inline char getCharAndSize(const char *Ptr, unsigned &Size) {
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// If this is not a trigraph and not a UCN or escaped newline, return
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// quickly.
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if (isObviouslySimpleCharacter(Ptr[0])) {
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Size = 1;
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return *Ptr;
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}
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Size = 0;
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return getCharAndSizeSlow(Ptr, Size);
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}
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/// getCharAndSizeSlow - Handle the slow/uncommon case of the getCharAndSize
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/// method.
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char getCharAndSizeSlow(const char *Ptr, unsigned &Size, Token *Tok = 0);
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public:
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/// getCharAndSizeNoWarn - Like the getCharAndSize method, but does not ever
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/// emit a warning.
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static inline char getCharAndSizeNoWarn(const char *Ptr, unsigned &Size,
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const LangOptions &Features) {
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// If this is not a trigraph and not a UCN or escaped newline, return
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// quickly.
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if (isObviouslySimpleCharacter(Ptr[0])) {
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Size = 1;
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return *Ptr;
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}
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Size = 0;
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return getCharAndSizeSlowNoWarn(Ptr, Size, Features);
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}
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/// getEscapedNewLineSize - Return the size of the specified escaped newline,
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/// or 0 if it is not an escaped newline. P[-1] is known to be a "\" on entry
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/// to this function.
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static unsigned getEscapedNewLineSize(const char *P);
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/// SkipEscapedNewLines - If P points to an escaped newline (or a series of
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/// them), skip over them and return the first non-escaped-newline found,
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/// otherwise return P.
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static const char *SkipEscapedNewLines(const char *P);
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private:
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/// getCharAndSizeSlowNoWarn - Same as getCharAndSizeSlow, but never emits a
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/// diagnostic.
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static char getCharAndSizeSlowNoWarn(const char *Ptr, unsigned &Size,
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const LangOptions &Features);
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//===--------------------------------------------------------------------===//
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// Other lexer functions.
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// Helper functions to lex the remainder of a token of the specific type.
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void LexIdentifier (Token &Result, const char *CurPtr);
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void LexNumericConstant (Token &Result, const char *CurPtr);
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void LexStringLiteral (Token &Result, const char *CurPtr,bool Wide);
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void LexAngledStringLiteral(Token &Result, const char *CurPtr);
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void LexCharConstant (Token &Result, const char *CurPtr);
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bool LexEndOfFile (Token &Result, const char *CurPtr);
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bool SkipWhitespace (Token &Result, const char *CurPtr);
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bool SkipBCPLComment (Token &Result, const char *CurPtr);
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bool SkipBlockComment (Token &Result, const char *CurPtr);
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bool SaveBCPLComment (Token &Result, const char *CurPtr);
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bool IsStartOfConflictMarker(const char *CurPtr);
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bool HandleEndOfConflictMarker(const char *CurPtr);
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};
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} // end namespace clang
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#endif
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