//===--- MacroInfo.cpp - Information about #defined identifiers -----------===//
//
//                     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 MacroInfo interface.
//
//===----------------------------------------------------------------------===//

#include "clang/Lex/MacroInfo.h"
#include "clang/Lex/Preprocessor.h"
using namespace clang;

MacroInfo::MacroInfo(SourceLocation DefLoc)
  : Location(DefLoc),
    PreviousDefinition(0),
    ArgumentList(0),
    NumArguments(0),
    IsDefinitionLengthCached(false),
    IsFunctionLike(false),
    IsC99Varargs(false),
    IsGNUVarargs(false),
    IsBuiltinMacro(false),
    IsFromAST(false),
    ChangedAfterLoad(false),
    IsDisabled(false),
    IsUsed(false),
    IsAllowRedefinitionsWithoutWarning(false),
    IsWarnIfUnused(false),
    IsPublic(true),
    IsHidden(false),
    IsAmbiguous(false) {
}

MacroInfo::MacroInfo(const MacroInfo &MI, llvm::BumpPtrAllocator &PPAllocator)
  : Location(MI.Location),
    EndLocation(MI.EndLocation),
    UndefLocation(MI.UndefLocation),
    PreviousDefinition(0),
    ArgumentList(0),
    NumArguments(0),
    ReplacementTokens(MI.ReplacementTokens),
    DefinitionLength(MI.DefinitionLength),
    IsDefinitionLengthCached(MI.IsDefinitionLengthCached),
    IsFunctionLike(MI.IsFunctionLike),
    IsC99Varargs(MI.IsC99Varargs),
    IsGNUVarargs(MI.IsGNUVarargs),
    IsBuiltinMacro(MI.IsBuiltinMacro),
    IsFromAST(MI.IsFromAST),
    ChangedAfterLoad(MI.ChangedAfterLoad),
    IsDisabled(MI.IsDisabled),
    IsUsed(MI.IsUsed),
    IsAllowRedefinitionsWithoutWarning(MI.IsAllowRedefinitionsWithoutWarning),
    IsWarnIfUnused(MI.IsWarnIfUnused),
    IsPublic(MI.IsPublic),
    IsHidden(MI.IsHidden),
    IsAmbiguous(MI.IsAmbiguous) {
  setArgumentList(MI.ArgumentList, MI.NumArguments, PPAllocator);
}

const MacroInfo *MacroInfo::findDefinitionAtLoc(SourceLocation L,
                                                SourceManager &SM) const {
  assert(L.isValid() && "SourceLocation is invalid.");
  for (const MacroInfo *MI = this; MI; MI = MI->PreviousDefinition) {
    if (MI->Location.isInvalid() ||  // For macros defined on the command line.
        SM.isBeforeInTranslationUnit(MI->Location, L))
      return (MI->UndefLocation.isInvalid() ||
              SM.isBeforeInTranslationUnit(L, MI->UndefLocation)) ? MI : NULL;
  }
  return NULL;
}

unsigned MacroInfo::getDefinitionLengthSlow(SourceManager &SM) const {
  assert(!IsDefinitionLengthCached);
  IsDefinitionLengthCached = true;

  if (ReplacementTokens.empty())
    return (DefinitionLength = 0);

  const Token &firstToken = ReplacementTokens.front();
  const Token &lastToken = ReplacementTokens.back();
  SourceLocation macroStart = firstToken.getLocation();
  SourceLocation macroEnd = lastToken.getLocation();
  assert(macroStart.isValid() && macroEnd.isValid());
  assert((macroStart.isFileID() || firstToken.is(tok::comment)) &&
         "Macro defined in macro?");
  assert((macroEnd.isFileID() || lastToken.is(tok::comment)) &&
         "Macro defined in macro?");
  std::pair<FileID, unsigned>
      startInfo = SM.getDecomposedExpansionLoc(macroStart);
  std::pair<FileID, unsigned>
      endInfo = SM.getDecomposedExpansionLoc(macroEnd);
  assert(startInfo.first == endInfo.first &&
         "Macro definition spanning multiple FileIDs ?");
  assert(startInfo.second <= endInfo.second);
  DefinitionLength = endInfo.second - startInfo.second;
  DefinitionLength += lastToken.getLength();

  return DefinitionLength;
}

/// isIdenticalTo - Return true if the specified macro definition is equal to
/// this macro in spelling, arguments, and whitespace.  This is used to emit
/// duplicate definition warnings.  This implements the rules in C99 6.10.3.
///
bool MacroInfo::isIdenticalTo(const MacroInfo &Other, Preprocessor &PP) const {
  // Check # tokens in replacement, number of args, and various flags all match.
  if (ReplacementTokens.size() != Other.ReplacementTokens.size() ||
      getNumArgs() != Other.getNumArgs() ||
      isFunctionLike() != Other.isFunctionLike() ||
      isC99Varargs() != Other.isC99Varargs() ||
      isGNUVarargs() != Other.isGNUVarargs())
    return false;

  // Check arguments.
  for (arg_iterator I = arg_begin(), OI = Other.arg_begin(), E = arg_end();
       I != E; ++I, ++OI)
    if (*I != *OI) return false;

  // Check all the tokens.
  for (unsigned i = 0, e = ReplacementTokens.size(); i != e; ++i) {
    const Token &A = ReplacementTokens[i];
    const Token &B = Other.ReplacementTokens[i];
    if (A.getKind() != B.getKind())
      return false;

    // If this isn't the first first token, check that the whitespace and
    // start-of-line characteristics match.
    if (i != 0 &&
        (A.isAtStartOfLine() != B.isAtStartOfLine() ||
         A.hasLeadingSpace() != B.hasLeadingSpace()))
      return false;

    // If this is an identifier, it is easy.
    if (A.getIdentifierInfo() || B.getIdentifierInfo()) {
      if (A.getIdentifierInfo() != B.getIdentifierInfo())
        return false;
      continue;
    }

    // Otherwise, check the spelling.
    if (PP.getSpelling(A) != PP.getSpelling(B))
      return false;
  }

  return true;
}