Coverage Report

Created: 2019-03-22 08:08

/Users/buildslave/jenkins/workspace/clang-stage2-coverage-R/llvm/tools/clang/include/clang/Lex/TokenLexer.h
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//===- TokenLexer.h - Lex from a token buffer -------------------*- C++ -*-===//
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//
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// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
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// See https://llvm.org/LICENSE.txt for license information.
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// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
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//
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//===----------------------------------------------------------------------===//
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//
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// This file defines the TokenLexer interface.
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//
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//===----------------------------------------------------------------------===//
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#ifndef LLVM_CLANG_LEX_TOKENLEXER_H
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#define LLVM_CLANG_LEX_TOKENLEXER_H
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#include "clang/Basic/SourceLocation.h"
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#include "llvm/ADT/ArrayRef.h"
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namespace clang {
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class MacroArgs;
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class MacroInfo;
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class Preprocessor;
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class Token;
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class VAOptExpansionContext;
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/// TokenLexer - This implements a lexer that returns tokens from a macro body
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/// or token stream instead of lexing from a character buffer.  This is used for
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/// macro expansion and _Pragma handling, for example.
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class TokenLexer {
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  friend class Preprocessor;
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  /// The macro we are expanding from. This is null if expanding a token stream.
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  MacroInfo *Macro = nullptr;
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  /// The actual arguments specified for a function-like macro, or null. The
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  /// TokenLexer owns the pointed-to object.
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  MacroArgs *ActualArgs = nullptr;
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  /// The current preprocessor object we are expanding for.
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  Preprocessor &PP;
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  /// This is the pointer to an array of tokens that the macro is
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  /// defined to, with arguments expanded for function-like macros.  If this is
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  /// a token stream, these are the tokens we are returning.  This points into
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  /// the macro definition we are lexing from, a cache buffer that is owned by
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  /// the preprocessor, or some other buffer that we may or may not own
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  /// (depending on OwnsTokens).
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  /// Note that if it points into Preprocessor's cache buffer, the Preprocessor
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  /// may update the pointer as needed.
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  const Token *Tokens;
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  /// This is the length of the Tokens array.
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  unsigned NumTokens;
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  /// This is the index of the next token that Lex will return.
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  unsigned CurTokenIdx;
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  /// The source location range where this macro was expanded.
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  SourceLocation ExpandLocStart, ExpandLocEnd;
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  /// Source location pointing at the source location entry chunk that
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  /// was reserved for the current macro expansion.
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  SourceLocation MacroExpansionStart;
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  /// The offset of the macro expansion in the
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  /// "source location address space".
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  unsigned MacroStartSLocOffset;
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  /// Location of the macro definition.
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  SourceLocation MacroDefStart;
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  /// Length of the macro definition.
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  unsigned MacroDefLength;
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  /// Lexical information about the expansion point of the macro: the identifier
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  /// that the macro expanded from had these properties.
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  bool AtStartOfLine : 1;
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  bool HasLeadingSpace : 1;
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  // When this is true, the next token appended to the
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  // output list during function argument expansion will get a leading space,
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  // regardless of whether it had one to begin with or not. This is used for
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  // placemarker support. If still true after function argument expansion, the
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  // leading space will be applied to the first token following the macro
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  // expansion.
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  bool NextTokGetsSpace : 1;
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  /// This is true if this TokenLexer allocated the Tokens
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  /// array, and thus needs to free it when destroyed.  For simple object-like
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  /// macros (for example) we just point into the token buffer of the macro
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  /// definition, we don't make a copy of it.
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  bool OwnsTokens : 1;
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  /// This is true when tokens lexed from the TokenLexer
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  /// should not be subject to further macro expansion.
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  bool DisableMacroExpansion : 1;
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public:
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  /// Create a TokenLexer for the specified macro with the specified actual
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  /// arguments.  Note that this ctor takes ownership of the ActualArgs pointer.
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  /// ILEnd specifies the location of the ')' for a function-like macro or the
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  /// identifier for an object-like macro.
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  TokenLexer(Token &Tok, SourceLocation ILEnd, MacroInfo *MI,
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             MacroArgs *ActualArgs, Preprocessor &pp)
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      : PP(pp), OwnsTokens(false) {
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    Init(Tok, ILEnd, MI, ActualArgs);
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  }
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  /// Create a TokenLexer for the specified token stream.  If 'OwnsTokens' is
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  /// specified, this takes ownership of the tokens and delete[]'s them when
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  /// the token lexer is empty.
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  TokenLexer(const Token *TokArray, unsigned NumToks, bool DisableExpansion,
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             bool ownsTokens, Preprocessor &pp)
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      : PP(pp), OwnsTokens(false) {
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    Init(TokArray, NumToks, DisableExpansion, ownsTokens);
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  }
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  TokenLexer(const TokenLexer &) = delete;
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  TokenLexer &operator=(const TokenLexer &) = delete;
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  ~TokenLexer() { destroy(); }
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  /// Initialize this TokenLexer to expand from the specified macro
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  /// with the specified argument information.  Note that this ctor takes
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  /// ownership of the ActualArgs pointer.  ILEnd specifies the location of the
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  /// ')' for a function-like macro or the identifier for an object-like macro.
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  void Init(Token &Tok, SourceLocation ELEnd, MacroInfo *MI,
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            MacroArgs *Actuals);
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  /// Initialize this TokenLexer with the specified token stream.
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  /// This does not take ownership of the specified token vector.
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  ///
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  /// DisableExpansion is true when macro expansion of tokens lexed from this
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  /// stream should be disabled.
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  void Init(const Token *TokArray, unsigned NumToks,
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            bool DisableMacroExpansion, bool OwnsTokens);
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  /// If the next token lexed will pop this macro off the
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  /// expansion stack, return 2.  If the next unexpanded token is a '(', return
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  /// 1, otherwise return 0.
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  unsigned isNextTokenLParen() const;
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  /// Lex and return a token from this macro stream.
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  bool Lex(Token &Tok);
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  /// isParsingPreprocessorDirective - Return true if we are in the middle of a
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  /// preprocessor directive.
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  bool isParsingPreprocessorDirective() const;
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private:
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  void destroy();
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  /// Return true if the next lex call will pop this macro off the include
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  /// stack.
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  bool isAtEnd() const {
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    return CurTokenIdx == NumTokens;
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  }
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  /// Concatenates the next (sub-)sequence of \p Tokens separated by '##'
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  /// starting with LHSTok - stopping when we encounter a token that is neither
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  /// '##' nor preceded by '##'.  Places the result back into \p LHSTok and sets
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  /// \p CurIdx to point to the token following the last one that was pasted.
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  ///
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  /// Also performs the MSVC extension wide-literal token pasting involved with:
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  ///       \code L #macro-arg. \endcode
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  ///
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  /// \param[in,out] LHSTok - Contains the token to the left of '##' in \p
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  /// Tokens upon entry and will contain the resulting concatenated Token upon
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  /// exit.
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  ///
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  /// \param[in] TokenStream - The stream of Tokens we are lexing from.
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  ///
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  /// \param[in,out] CurIdx - Upon entry, \pTokens[\pCurIdx] must equal '##'
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  /// (with the exception of the MSVC extension mentioned above).  Upon exit, it
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  /// is set to the index of the token following the last token that was
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  /// concatenated together.
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  ///
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  /// \returns If this returns true, the caller should immediately return the
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  /// token.
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  bool pasteTokens(Token &LHSTok, ArrayRef<Token> TokenStream,
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                   unsigned int &CurIdx);
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  /// Calls pasteTokens above, passing in the '*this' object's Tokens and
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  /// CurTokenIdx data members.
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  bool pasteTokens(Token &Tok);
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  /// Takes the tail sequence of tokens within ReplacementToks that represent
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  /// the just expanded __VA_OPT__ tokens (possibly zero tokens) and transforms
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  /// them into a string.  \p VCtx is used to determine which token represents
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  /// the first __VA_OPT__ replacement token.
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  ///
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  /// \param[in,out] ResultToks - Contains the current Replacement Tokens
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  /// (prior to rescanning and token pasting), the tail end of which represents
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  /// the tokens just expanded through __VA_OPT__ processing.  These (sub)
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  /// sequence of tokens are folded into one stringified token.
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  ///
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  /// \param[in] VCtx - contains relevant contextual information about the
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  /// state of the tokens around and including the __VA_OPT__ token, necessary
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  /// for stringification.
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  void stringifyVAOPTContents(SmallVectorImpl<Token> &ResultToks,
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                              const VAOptExpansionContext &VCtx,
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                              SourceLocation VAOPTClosingParenLoc);
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  /// Expand the arguments of a function-like macro so that we can quickly
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  /// return preexpanded tokens from Tokens.
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  void ExpandFunctionArguments();
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  /// In microsoft compatibility mode, /##/ pastes
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  /// together to form a comment that comments out everything in the current
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  /// macro, other active macros, and anything left on the current physical
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  /// source line of the expanded buffer.  Handle this by returning the
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  /// first token on the next line.
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  void HandleMicrosoftCommentPaste(Token &Tok, SourceLocation OpLoc);
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  /// If \p loc is a FileID and points inside the current macro
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  /// definition, returns the appropriate source location pointing at the
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  /// macro expansion source location entry.
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  SourceLocation getExpansionLocForMacroDefLoc(SourceLocation loc) const;
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  /// Creates SLocEntries and updates the locations of macro argument
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  /// tokens to their new expanded locations.
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  ///
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  /// \param ArgIdSpellLoc the location of the macro argument id inside the
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  /// macro definition.
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  void updateLocForMacroArgTokens(SourceLocation ArgIdSpellLoc,
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                                  Token *begin_tokens, Token *end_tokens);
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  /// Remove comma ahead of __VA_ARGS__, if present, according to compiler
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  /// dialect settings.  Returns true if the comma is removed.
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  bool MaybeRemoveCommaBeforeVaArgs(SmallVectorImpl<Token> &ResultToks,
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                                    bool HasPasteOperator,
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                                    MacroInfo *Macro, unsigned MacroArgNo,
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                                    Preprocessor &PP);
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  void PropagateLineStartLeadingSpaceInfo(Token &Result);
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};
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} // namespace clang
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#endif // LLVM_CLANG_LEX_TOKENLEXER_H