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//===--- TokenLexer.h - Lex from a token buffer -----------------*- 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 TokenLexer interface.
#include "clang/Basic/SourceLocation.h"
namespace clang {
class MacroInfo;
class Preprocessor;
class Token;
class MacroArgs;
/// TokenLexer - This implements a lexer that returns tokens from a macro body
/// or token stream instead of lexing from a character buffer. This is used for
/// macro expansion and _Pragma handling, for example.
class TokenLexer {
/// Macro - The macro we are expanding from. This is null if expanding a
/// token stream.
MacroInfo *Macro;
/// ActualArgs - The actual arguments specified for a function-like macro, or
/// null. The TokenLexer owns the pointed-to object.
MacroArgs *ActualArgs;
/// PP - The current preprocessor object we are expanding for.
Preprocessor &PP;
/// Tokens - This is the pointer to an array of tokens that the macro is
/// defined to, with arguments expanded for function-like macros. If this is
/// a token stream, these are the tokens we are returning. This points into
/// the macro definition we are lexing from, a cache buffer that is owned by
/// the preprocessor, or some other buffer that we may or may not own
/// (depending on OwnsTokens).
/// Note that if it points into Preprocessor's cache buffer, the Preprocessor
/// may update the pointer as needed.
const Token *Tokens;
friend class Preprocessor;
/// NumTokens - This is the length of the Tokens array.
unsigned NumTokens;
/// CurToken - This is the next token that Lex will return.
unsigned CurToken;
/// ExpandLocStart/End - The source location range where this macro was
/// expanded.
SourceLocation ExpandLocStart, ExpandLocEnd;
/// \brief Source location pointing at the source location entry chunk that
/// was reserved for the current macro expansion.
SourceLocation MacroExpansionStart;
/// \brief The offset of the macro expansion in the
/// "source location address space".
unsigned MacroStartSLocOffset;
/// \brief Location of the macro definition.
SourceLocation MacroDefStart;
/// \brief Length of the macro definition.
unsigned MacroDefLength;
/// Lexical information about the expansion point of the macro: the identifier
/// that the macro expanded from had these properties.
bool AtStartOfLine : 1;
bool HasLeadingSpace : 1;
// NextTokGetsSpace - When this is true, the next token appended to the
// output list during function argument expansion will get a leading space,
// regardless of whether it had one to begin with or not. This is used for
// placemarker support. If still true after function argument expansion, the
// leading space will be applied to the first token following the macro
// expansion.
bool NextTokGetsSpace : 1;
/// OwnsTokens - This is true if this TokenLexer allocated the Tokens
/// array, and thus needs to free it when destroyed. For simple object-like
/// macros (for example) we just point into the token buffer of the macro
/// definition, we don't make a copy of it.
bool OwnsTokens : 1;
/// DisableMacroExpansion - This is true when tokens lexed from the TokenLexer
/// should not be subject to further macro expansion.
bool DisableMacroExpansion : 1;
TokenLexer(const TokenLexer &) = delete;
void operator=(const TokenLexer &) = delete;
/// Create a TokenLexer for the specified macro with the specified actual
/// arguments. Note that this ctor takes ownership of the ActualArgs pointer.
/// ILEnd specifies the location of the ')' for a function-like macro or the
/// identifier for an object-like macro.
TokenLexer(Token &Tok, SourceLocation ILEnd, MacroInfo *MI,
MacroArgs *ActualArgs, Preprocessor &pp)
: Macro(nullptr), ActualArgs(nullptr), PP(pp), OwnsTokens(false) {
Init(Tok, ILEnd, MI, ActualArgs);
/// Init - Initialize this TokenLexer to expand from the specified macro
/// with the specified argument information. Note that this ctor takes
/// ownership of the ActualArgs pointer. ILEnd specifies the location of the
/// ')' for a function-like macro or the identifier for an object-like macro.
void Init(Token &Tok, SourceLocation ILEnd, MacroInfo *MI,
MacroArgs *ActualArgs);
/// Create a TokenLexer for the specified token stream. If 'OwnsTokens' is
/// specified, this takes ownership of the tokens and delete[]'s them when
/// the token lexer is empty.
TokenLexer(const Token *TokArray, unsigned NumToks, bool DisableExpansion,
bool ownsTokens, Preprocessor &pp)
: Macro(nullptr), ActualArgs(nullptr), PP(pp), OwnsTokens(false) {
Init(TokArray, NumToks, DisableExpansion, ownsTokens);
/// Init - Initialize this TokenLexer with the specified token stream.
/// This does not take ownership of the specified token vector.
/// DisableExpansion is true when macro expansion of tokens lexed from this
/// stream should be disabled.
void Init(const Token *TokArray, unsigned NumToks,
bool DisableMacroExpansion, bool OwnsTokens);
~TokenLexer() { destroy(); }
/// isNextTokenLParen - If the next token lexed will pop this macro off the
/// expansion stack, return 2. If the next unexpanded token is a '(', return
/// 1, otherwise return 0.
unsigned isNextTokenLParen() const;
/// Lex - Lex and return a token from this macro stream.
bool Lex(Token &Tok);
/// isParsingPreprocessorDirective - Return true if we are in the middle of a
/// preprocessor directive.
bool isParsingPreprocessorDirective() const;
void destroy();
/// isAtEnd - Return true if the next lex call will pop this macro off the
/// include stack.
bool isAtEnd() const {
return CurToken == NumTokens;
/// PasteTokens - Tok is the LHS of a ## operator, and CurToken is the ##
/// operator. Read the ## and RHS, and paste the LHS/RHS together. If there
/// are is another ## after it, chomp it iteratively. Return the result as
/// Tok. If this returns true, the caller should immediately return the
/// token.
bool PasteTokens(Token &Tok);
/// Expand the arguments of a function-like macro so that we can quickly
/// return preexpanded tokens from Tokens.
void ExpandFunctionArguments();
/// HandleMicrosoftCommentPaste - In microsoft compatibility mode, /##/ pastes
/// together to form a comment that comments out everything in the current
/// macro, other active macros, and anything left on the current physical
/// source line of the expanded buffer. Handle this by returning the
/// first token on the next line.
void HandleMicrosoftCommentPaste(Token &Tok, SourceLocation OpLoc);
/// \brief If \p loc is a FileID and points inside the current macro
/// definition, returns the appropriate source location pointing at the
/// macro expansion source location entry.
SourceLocation getExpansionLocForMacroDefLoc(SourceLocation loc) const;
/// \brief Creates SLocEntries and updates the locations of macro argument
/// tokens to their new expanded locations.
/// \param ArgIdSpellLoc the location of the macro argument id inside the
/// macro definition.
void updateLocForMacroArgTokens(SourceLocation ArgIdSpellLoc,
Token *begin_tokens, Token *end_tokens);
/// Remove comma ahead of __VA_ARGS__, if present, according to compiler
/// dialect settings. Returns true if the comma is removed.
bool MaybeRemoveCommaBeforeVaArgs(SmallVectorImpl<Token> &ResultToks,
bool HasPasteOperator,
MacroInfo *Macro, unsigned MacroArgNo,
Preprocessor &PP);
void PropagateLineStartLeadingSpaceInfo(Token &Result);
} // end namespace clang