path: root/lib/Lex/PPDirectives.cpp

//===--- PPDirectives.cpp - Directive Handling for Preprocessor -----------===//
//
//                     The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
//  This file implements # directive processing for the Preprocessor.
//
//===----------------------------------------------------------------------===//

#include "clang/Lex/Preprocessor.h"
#include "clang/Lex/HeaderSearch.h"
#include "clang/Lex/MacroInfo.h"
#include "clang/Basic/Diagnostic.h"
#include "clang/Basic/SourceManager.h"
using namespace clang;

//===----------------------------------------------------------------------===//
// Utility Methods for Preprocessor Directive Handling.
//===----------------------------------------------------------------------===//

/// DiscardUntilEndOfDirective - Read and discard all tokens remaining on the
/// current line until the tok::eom token is found.
void Preprocessor::DiscardUntilEndOfDirective() {
  Token Tmp;
  do {
    LexUnexpandedToken(Tmp);
  } while (Tmp.isNot(tok::eom));
}

/// isCXXNamedOperator - Returns "true" if the token is a named operator in C++.
static bool isCXXNamedOperator(const std::string &Spelling) {
  return Spelling == "and" || Spelling == "bitand" || Spelling == "bitor" ||
    Spelling == "compl" || Spelling == "not" || Spelling == "not_eq" ||
    Spelling == "or" || Spelling == "xor";
}

/// ReadMacroName - Lex and validate a macro name, which occurs after a
/// #define or #undef.  This sets the token kind to eom and discards the rest
/// of the macro line if the macro name is invalid.  isDefineUndef is 1 if
/// this is due to a a #define, 2 if #undef directive, 0 if it is something
/// else (e.g. #ifdef).
void Preprocessor::ReadMacroName(Token &MacroNameTok, char isDefineUndef) {
  // Read the token, don't allow macro expansion on it.
  LexUnexpandedToken(MacroNameTok);
  
  // Missing macro name?
  if (MacroNameTok.is(tok::eom)) {
    Diag(MacroNameTok, diag::err_pp_missing_macro_name);
    return;
  }
  
  IdentifierInfo *II = MacroNameTok.getIdentifierInfo();
  if (II == 0) {
    std::string Spelling = getSpelling(MacroNameTok);
    if (isCXXNamedOperator(Spelling))
      // C++ 2.5p2: Alternative tokens behave the same as its primary token
      // except for their spellings.
      Diag(MacroNameTok, diag::err_pp_operator_used_as_macro_name) << Spelling;
    else
      Diag(MacroNameTok, diag::err_pp_macro_not_identifier);
    // Fall through on error.
  } else if (isDefineUndef && II->getPPKeywordID() == tok::pp_defined) {
    // Error if defining "defined": C99 6.10.8.4.
    Diag(MacroNameTok, diag::err_defined_macro_name);
  } else if (isDefineUndef && II->hasMacroDefinition() &&
             getMacroInfo(II)->isBuiltinMacro()) {
    // Error if defining "__LINE__" and other builtins: C99 6.10.8.4.
    if (isDefineUndef == 1)
      Diag(MacroNameTok, diag::pp_redef_builtin_macro);
    else
      Diag(MacroNameTok, diag::pp_undef_builtin_macro);
  } else {
    // Okay, we got a good identifier node.  Return it.
    return;
  }
  
  // Invalid macro name, read and discard the rest of the line.  Then set the
  // token kind to tok::eom.
  MacroNameTok.setKind(tok::eom);
  return DiscardUntilEndOfDirective();
}

/// CheckEndOfDirective - Ensure that the next token is a tok::eom token.  If
/// not, emit a diagnostic and consume up until the eom.
void Preprocessor::CheckEndOfDirective(const char *DirType) {
  Token Tmp;
  // Lex unexpanded tokens: macros might expand to zero tokens, causing us to
  // miss diagnosing invalid lines.
  LexUnexpandedToken(Tmp);
  
  // There should be no tokens after the directive, but we allow them as an
  // extension.
  while (Tmp.is(tok::comment))  // Skip comments in -C mode.
    LexUnexpandedToken(Tmp);
  
  if (Tmp.isNot(tok::eom)) {
    Diag(Tmp, diag::ext_pp_extra_tokens_at_eol) << DirType;
    DiscardUntilEndOfDirective();
  }
}



/// SkipExcludedConditionalBlock - We just read a #if or related directive and
/// decided that the subsequent tokens are in the #if'd out porti