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//===--- 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/PreprocessorLexer.h"
#include "clang/Basic/LangOptions.h"
#include "llvm/ADT/SmallVector.h"
#include <string>
#include <cassert>
namespace clang {
class DiagnosticsEngine;
class SourceManager;
class Preprocessor;
class DiagnosticBuilder;
/// ConflictMarkerKind - Kinds of conflict marker which the lexer might be
/// recovering from.
enum ConflictMarkerKind {
/// Not within a conflict marker.
CMK_None,
/// A normal or diff3 conflict marker, initiated by at least 7 <s,
/// separated by at least 7 =s or |s, and terminated by at least 7 >s.
CMK_Normal,
/// A Perforce-style conflict marker, initiated by 4 >s, separated by 4 =s,
/// and terminated by 4 <s.
CMK_Perforce
};
/// 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 : public PreprocessorLexer {
virtual void anchor();
//===--------------------------------------------------------------------===//
// 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.
LangOptions LangOpts; // LangOpts enabled by this language (cache).
bool Is_PragmaLexer; // True if lexer for _Pragma handling.
//===--------------------------------------------------------------------===//
// Context-specific lexing flags set by the preprocessor.
//
/// ExtendedTokenMode - The lexer can optionally keep comments and whitespace
/// and return them as tokens. This is used for -C and -CC modes, and
/// whitespace preservation can be useful for some clients that want to lex
/// the file in raw mode and get every character from the file.
///
/// When this is set to 2 it returns comments and whitespace. When set to 1
/// it returns comments, when it is set to 0 it returns normal tokens only.
unsigned char ExtendedTokenMode;
//===--------------------------------------------------------------------===//
// 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;
// CurrentConflictMarkerState - The kind of conflict marker we are handling.
ConflictMarkerKind CurrentConflictMarkerState;
Lexer(const Lexer&); // DO NOT IMPLEMENT
void operator=(const Lexer&); // DO NOT IMPLEMENT
friend class Preprocessor;
void InitLexer(const char *BufStart, const char *BufPtr, const char *BufEnd);
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(FileID FID, const llvm::MemoryBuffer *InputBuffer, Preprocessor &PP);
/// 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 &LangOpts,
const char *BufStart, const char *BufPtr, const char *BufEnd);
/// 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(FileID FID, const llvm::MemoryBuffer *InputBuffer,
const SourceManager &SM, const LangOptions &LangOpts);
/// Create_PragmaLexer: Lexer constructor - Create a new lexer object for
/// _Pragma expansion. This has a variety of magic semantics that this method
/// sets up. It returns a new'd Lexer that must be delete'd when done.
static Lexer *Create_PragmaLexer(SourceLocation SpellingLoc,
SourceLocation ExpansionLocStart,
SourceLocation ExpansionLocEnd,
unsigned TokLen, Preprocessor &PP);
/// getLangOpts - Return the language features currently enabled.
/// NOTE: this lexer modifies features as a file is parsed!
const LangOptions &getLangOpts() const { return LangOpts; }
/// 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);
}
/// isPragmaLexer - Returns true if this Lexer is being used to lex a pragma.
bool isPragmaLexer() const { return Is_PragmaLexer; }
/// IndirectLex - An indirect call to 'Lex' that can be invoked via
/// the PreprocessorLexer interface.
void IndirectLex(Token &Result) { Lex(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 at 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;
}
/// isKeepWhitespaceMode - Return true if the lexer should return tokens for
/// every character in the file, including whitespace and comments. This
/// should only be used in raw mode, as the preprocessor is not prepared to
/// deal with the excess tokens.
bool isKeepWhitespaceMode() const {
return ExtendedTokenMode > 1;
}
/// SetKeepWhitespaceMode - This method lets clients enable or disable
/// whitespace retention mode.
void SetKeepWhitespaceMode(bool Val) {
assert((!Val || LexingRawMode) &&
"Can only enable whitespace retention in raw mode");
ExtendedTokenMode = Val ? 2 : 0;
}
/// inKeepCommentMode - Return true if the lexer should return comments as
/// tokens.
bool inKeepCommentMode() const {
return ExtendedTokenMode > 0;
}
/// 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) {
assert(!isKeepWhitespaceMode() &&
"Can't play with comment retention state when retaining whitespace");
ExtendedTokenMode = Mode ? 1 : 0;
}
const char *getBufferStart() const { return BufferStart; }
/// 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.
DiagnosticBuilder Diag(const char *Loc, unsigned DiagID) const;
/// getSourceLocation - Return a source location identifier for the specified
/// offset in the current file.
SourceLocation getSourceLocation(const char *Loc, unsigned TokLen = 1) const;
/// getSourceLocation - Return a source location for the next character in
/// the current file.
SourceLocation getSourceLocation() { return getSourceLocation(BufferPtr); }
/// \brief Return the current location in the buffer.
const char *getBufferLocation() const { return BufferPtr; }
/// 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(SmallVectorImpl<char> &Str);
/// getSpelling - This method is used to get the spelling of a token into a
/// preallocated buffer, instead of as an std::string. The caller is required
/// to allocate enough space for the token, which is guaranteed to be at least
/// Tok.getLength() bytes long. The length of the actual result is returned.
///
/// Note that this method may do two possible things: it may either fill in
/// the buffer specified with characters, or it may *change the input pointer*
/// to point to a constant buffer with the data already in it (avoiding a
/// copy). The caller is not allowed to modify the returned buffer pointer
/// if an internal buffer is returned.
static unsigned getSpelling(const Token &Tok, const char *&Buffer,
const SourceManager &SourceMgr,
const LangOptions &LangOpts,
bool *Invalid = 0);
/// getSpelling() - Return the 'spelling' of the Tok token. The spelling of a
/// token is the characters used to represent the token in the source file
/// after trigraph expansion and escaped-newline folding. In particular, this
/// wants to get the true, uncanonicalized, spelling of things like digraphs
/// UCNs, etc.
static std::string getSpelling(const Token &Tok,
const SourceManager &SourceMgr,
const LangOptions &LangOpts,
bool *Invalid = 0);
/// getSpelling - This method is used to get the spelling of the
/// token at the given source location. If, as is usually true, it
/// is not necessary to copy any data, then the returned string may
/// not point into the provided buffer.
///
/// This method lexes at the expansion depth of the given
/// location and does not jump to the expansion or spelling
/// location.
static StringRef getSpelling(SourceLocation loc,
SmallVectorImpl<char> &buffer,
const SourceManager &SourceMgr,
const LangOptions &LangOpts,
bool *invalid = 0);
/// 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,
const LangOptions &LangOpts);
/// \brief Given a location any where in a source buffer, find the location
/// that corresponds to the beginning of the token in which the original
/// source location lands.
///
/// \param Loc
static SourceLocation GetBeginningOfToken(SourceLocation Loc,
const SourceManager &SM,
const LangOptions &LangOpts);
/// AdvanceToTokenCharacter - If the current SourceLocation specifies a
/// location at the start of a token, return a new location that specifies a
/// character within the token. This handles trigraphs and escaped newlines.
static SourceLocation AdvanceToTokenCharacter(SourceLocation TokStart,
unsigned Character,
const SourceManager &SM,
const LangOptions &LangOpts);
/// \brief Computes the source location just past the end of the
/// token at this source location.
///
/// This routine can be used to produce a source location that
/// points just past the end of the token referenced by \p Loc, and
/// is generally used when a diagnostic needs to point just after a
/// token where it expected something different that it received. If
/// the returned source location would not be meaningful (e.g., if
/// it points into a macro), this routine returns an invalid
/// source location.
///
/// \param Offset an offset from the end of the token, where the source
/// location should refer to. The default offset (0) produces a source
/// location pointing just past the end of the token; an offset of 1 produces
/// a source location pointing to the last character in the token, etc.
static SourceLocation getLocForEndOfToken(SourceLocation Loc, unsigned Offset,
const SourceManager &SM,
const LangOptions &LangOpts);
/// \brief Returns true if the given MacroID location points at the first
/// token of the macro expansion.
///
/// \param MacroBegin If non-null and function returns true, it is set to
/// begin location of the macro.
static bool isAtStartOfMacroExpansion(SourceLocation loc,
const SourceManager &SM,
const LangOptions &LangOpts,
SourceLocation *MacroBegin = 0);
/// \brief Returns true if the given MacroID location points at the last
/// token of the macro expansion.
///
/// \param MacroBegin If non-null and function returns true, it is set to
/// end location of the macro.
static bool isAtEndOfMacroExpansion(SourceLocation loc,
const SourceManager &SM,
const LangOptions &LangOpts,
SourceLocation *MacroEnd = 0);
/// \brief Accepts a range and returns a character range with file locations.
///
/// Returns a null range if a part of the range resides inside a macro
/// expansion or the range does not reside on the same FileID.
static CharSourceRange makeFileCharRange(CharSourceRange Range,
const SourceManager &SM,
const LangOptions &LangOpts);
/// \brief Returns a string for the source that the range encompasses.
static StringRef getSourceText(CharSourceRange Range,
const SourceManager &SM,
const LangOptions &LangOpts,
bool *Invalid = 0);
/// \brief Retrieve the name of the immediate macro expansion.
///
/// This routine starts from a source location, and finds the name of the macro
/// responsible for its immediate expansion. It looks through any intervening
/// macro argument expansions to compute this. It returns a StringRef which
/// refers to the SourceManager-owned buffer of the source where that macro
/// name is spelled. Thus, the result shouldn't out-live that SourceManager.
static StringRef getImmediateMacroName(SourceLocation Loc,
const SourceManager &SM,
const LangOptions &LangOpts);
/// \brief Compute the preamble of the given file.
///
/// The preamble of a file contains the initial comments, include directives,
/// and other preprocessor directives that occur before the code in this
/// particular file actually begins. The preamble of the main source file is
/// a potential prefix header.
///
/// \param Buffer The memory buffer containing the file's contents.
///
/// \param MaxLines If non-zero, restrict the length of the preamble
/// to fewer than this number of lines.
///
/// \returns The offset into the file where the preamble ends and the rest
/// of the file begins along with a boolean value indicating whether
/// the preamble ends at the beginning of a new line.
static std::pair<unsigned, bool>
ComputePreamble(const llvm::MemoryBuffer *Buffer, const LangOptions &LangOpts,
unsigned MaxLines = 0);
//===--------------------------------------------------------------------===//
// 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,
tok::TokenKind Kind) {
unsigned TokLen = TokEnd-BufferPtr;
Result.setLength(TokLen);
Result.setLocation(getSourceLocation(BufferPtr, TokLen));
Result.setKind(Kind);
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 getCharAndSize with
// ConsumeChar. getCharAndSize 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 getCharAndSize) 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);
public:
/// getCharAndSizeNoWarn - Like the getCharAndSize method, but does not ever
/// emit a warning.
static inline char getCharAndSizeNoWarn(const char *Ptr, unsigned &Size,
const LangOptions &LangOpts) {
// 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, LangOpts);
}
/// getEscapedNewLineSize - Return the size of the specified escaped newline,
/// or 0 if it is not an escaped newline. P[-1] is known to be a "\" on entry
/// to this function.
static unsigned getEscapedNewLineSize(const char *P);
/// SkipEscapedNewLines - If P points to an escaped newline (or a series of
/// them), skip over them and return the first non-escaped-newline found,
/// otherwise return P.
static const char *SkipEscapedNewLines(const char *P);
/// \brief Checks that the given token is the first token that occurs after
/// the given location (this excludes comments and whitespace). Returns the
/// location immediately after the specified token. If the token is not found
/// or the location is inside a macro, the returned source location will be
/// invalid.
static SourceLocation findLocationAfterToken(SourceLocation loc,
tok::TokenKind TKind,
const SourceManager &SM,
const LangOptions &LangOpts,
bool SkipTrailingWhitespaceAndNewLine);
private:
/// getCharAndSizeSlowNoWarn - Same as getCharAndSizeSlow, but never emits a
/// diagnostic.
static char getCharAndSizeSlowNoWarn(const char *Ptr, unsigned &Size,
const LangOptions &LangOpts);
//===--------------------------------------------------------------------===//
// Other lexer functions.
void SkipBytes(unsigned Bytes, bool StartOfLine);
const char *LexUDSuffix(Token &Result, const char *CurPtr);
// 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,
tok::TokenKind Kind);
void LexRawStringLiteral (Token &Result, const char *CurPtr,
tok::TokenKind Kind);
void LexAngledStringLiteral(Token &Result, const char *CurPtr);
void LexCharConstant (Token &Result, const char *CurPtr,
tok::TokenKind Kind);
bool LexEndOfFile (Token &Result, const char *CurPtr);
bool 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);
bool IsStartOfConflictMarker(const char *CurPtr);
bool HandleEndOfConflictMarker(const char *CurPtr);
bool isCodeCompletionPoint(const char *CurPtr) const;
void cutOffLexing() { BufferPtr = BufferEnd; }
};
} // end namespace clang
#endif