path: root/lib/Lex/PPMacroExpansion.cpp

//===--- MacroExpansion.cpp - Top level Macro Expansion -------------------===//
//
//                     The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file implements the top level handling of macro expasion for the
// preprocessor.
//
//===----------------------------------------------------------------------===//

#include "clang/Lex/Preprocessor.h"
#include "MacroArgs.h"
#include "clang/Lex/MacroInfo.h"
#include "clang/Basic/SourceManager.h"
#include "clang/Basic/FileManager.h"
#include "clang/Basic/TargetInfo.h"
#include "clang/Lex/LexDiagnostic.h"
#include "clang/Lex/CodeCompletionHandler.h"
#include "clang/Lex/ExternalPreprocessorSource.h"
#include "llvm/ADT/StringSwitch.h"
#include "llvm/ADT/STLExtras.h"
#include "llvm/Config/config.h"
#include "llvm/Support/raw_ostream.h"
#include <cstdio>
#include <ctime>
using namespace clang;

MacroInfo *Preprocessor::getInfoForMacro(IdentifierInfo *II) const {
  assert(II->hasMacroDefinition() && "Identifier is not a macro!");
  
  llvm::DenseMap<IdentifierInfo*, MacroInfo*>::const_iterator Pos
    = Macros.find(II);
  if (Pos == Macros.end()) {
    // Load this macro from the external source.
    getExternalSource()->LoadMacroDefinition(II);
    Pos = Macros.find(II);
  }
  assert(Pos != Macros.end() && "Identifier macro info is missing!");
  return Pos->second;
}

/// setMacroInfo - Specify a macro for this identifier.
///
void Preprocessor::setMacroInfo(IdentifierInfo *II, MacroInfo *MI) {
  if (MI) {
    Macros[II] = MI;
    II->setHasMacroDefinition(true);
  } else if (II->hasMacroDefinition()) {
    Macros.erase(II);
    II->setHasMacroDefinition(false);
  }
}

/// RegisterBuiltinMacro - Register the specified identifier in the identifier
/// table and mark it as a builtin macro to be expanded.
static IdentifierInfo *RegisterBuiltinMacro(Preprocessor &PP, const char *Name){
  // Get the identifier.
  IdentifierInfo *Id = PP.getIdentifierInfo(Name);

  // Mark it as being a macro that is builtin.
  MacroInfo *MI = PP.AllocateMacroInfo(SourceLocation());
  MI->setIsBuiltinMacro();
  PP.setMacroInfo(Id, MI);
  return Id;
}


/// RegisterBuiltinMacros - Register builtin macros, such as __LINE__ with the
/// identifier table.
void Preprocessor::RegisterBuiltinMacros() {
  Ident__LINE__ = RegisterBuiltinMacro(*this, "__LINE__");
  Ident__FILE__ = RegisterBuiltinMacro(*this, "__FILE__");
  Ident__DATE__ = RegisterBuiltinMacro(*this, "__DATE__");
  Ident__TIME__ = RegisterBuiltinMacro(*this, "__TIME__");
  Ident__COUNTER__ = RegisterBuiltinMacro(*this, "__COUNTER__");
  Ident_Pragma  = RegisterBuiltinMacro(*this, "_Pragma");

  // GCC Extensions.
  Ident__BASE_FILE__     = RegisterBuiltinMacro(*this, "__BASE_FILE__");
  Ident__INCLUDE_LEVEL__ = RegisterBuiltinMacro(*this, "__INCLUDE_LEVEL__");
  Ident__TIMESTAMP__     = RegisterBuiltinMacro(*this, "__TIMESTAMP__");

  // Clang Extensions.
  Ident__has_feature      = RegisterBuiltinMacro(*this, "__has_feature");
  Ident__has_extension    = RegisterBuiltinMacro(*this, "__has_extension");
  Ident__has_builtin      = RegisterBuiltinMacro(*this, "__has_builtin");
  Ident__has_attribute    = RegisterBuiltinMacro(*this, "__has_attribute");
  Ident__has_include      = RegisterBuiltinMacro(*this, "__has_include");
  Ident__has_include_next = RegisterBuiltinMacro(*this, "__has_include_next");

  // Microsoft Extensions.
  if (Features.Microsoft) 
    Ident__pragma = RegisterBuiltinMacro(*this, "__pragma");
  else
    Ident__pragma = 0;
}

/// isTrivialSingleTokenExpansion - Return true if MI, which has a single token
/// in its expansion, currently expands to that token literally.
static bool isTrivialSingleTokenExpansion(const MacroInfo *MI,
                                          const IdentifierInfo *MacroIdent,
                                          Preprocessor &PP) {
  IdentifierInfo *II = MI->getReplacementToken(0).getIdentifierInfo();

  // If the token isn't an identifier, it's always literally expanded.
  if (II == 0) return true;

  // If the identifier is a macro, and if that macro is enabled, it may be
  // expanded so it's not a trivial expansion.
  if (II->hasMacroDefinition() && PP.getMacroInfo(II)->isEnabled() &&
      // Fast expanding "#define X X" is ok, because X would be disabled.
      II != MacroIdent)
    return false;

  // If this is an object-like macro invocation, it is safe to trivially expand
  // it.
  if (MI->isObjectLike()) return true;

  // If this is a function-like macro invocation, it's safe to trivially expand
  // as long as the identifier is not a macro argument.
  for (MacroInfo::arg_iterator I = MI->arg_begin(), E = MI->arg_end();
       I != E; ++I)
    if (*I == II)
      return false;   // Identifier is a macro argument.

  return