C++ ExprResult::isValid方法代码示例

/// ParseMatchedBinaryArgs - Parse a pair of arguments who are
/// expected to be of the same type. Upon return, if both LHS and RHS
/// are valid then they are guaranteed to have the same type.
///
/// Name - The name token of the expression, for diagnostics.
/// ExpectType - The expected type of the arguments, if known.
void ParserImpl::ParseMatchedBinaryArgs(const Token &Name, 
                                        TypeResult ExpectType,
                                        ExprResult &LHS, ExprResult &RHS) {
  if (Tok.kind == Token::RParen) {
    Error("unexpected end of arguments.", Name);
    ConsumeRParen();
    return;
  }

  // Avoid NumberOrExprResult overhead and give more precise
  // diagnostics when we know the type.
  if (ExpectType.isValid()) {
    LHS = ParseExpr(ExpectType);
    if (Tok.kind == Token::RParen) {
      Error("unexpected end of arguments.", Name);
      ConsumeRParen();
      return;
    }
    RHS = ParseExpr(ExpectType);
  } else {
    NumberOrExprResult LHS_NOE = ParseNumberOrExpr();

    if (Tok.kind == Token::RParen) {
      Error("unexpected end of arguments.", Name);
      ConsumeRParen();
      return;
    }

    if (LHS_NOE.isNumber()) {
      NumberOrExprResult RHS_NOE = ParseNumberOrExpr();
      
      if (RHS_NOE.isNumber()) {
        Error("ambiguous arguments to expression.", Name);
      } else {
        RHS = RHS_NOE.getExpr();
        if (RHS.isValid())
          LHS = ParseNumberToken(RHS.get()->getWidth(), LHS_NOE.getNumber());
      }
    } else {
      LHS = LHS_NOE.getExpr();
      if (!LHS.isValid()) {
        // FIXME: Should suppress ambiguity warnings here.
        RHS = ParseExpr(TypeResult());
      } else {
        RHS = ParseExpr(LHS.get()->getWidth());
      }
    }
  }

  ExpectRParen("unexpected argument to expression.");
}

// FIXME: Rewrite to only accept binary form. Make type optional.
ExprResult ParserImpl::ParseConcatParenExpr(const Token &Name,
                                            Expr::Width ResTy) {
  std::vector<ExprHandle> Kids;
  
  unsigned Width = 0;
  while (Tok.kind != Token::RParen) {
    ExprResult E = ParseExpr(TypeResult());

    // Skip to end of expr on error.
    if (!E.isValid()) {
      SkipUntilRParen();
      return Builder->Constant(0, ResTy);
    }
    
    Kids.push_back(E.get());
    Width += E.get()->getWidth();
  }
  
  ConsumeRParen();

  if (Width != ResTy) {
    Error("concat does not match expected result size.");
    return Builder->Constant(0, ResTy);
  }

  // FIXME: Use builder!
  return ConcatExpr::createN(Kids.size(), &Kids[0]);
}

ExprResult ParserImpl::ParseUnaryParenExpr(const Token &Name,
                                           unsigned Kind, bool IsFixed,
                                           Expr::Width ResTy) {
  if (Tok.kind == Token::RParen) {
    Error("unexpected end of arguments.", Name);
    ConsumeRParen();
    return Builder->Constant(0, ResTy);
  }

  ExprResult Arg = ParseExpr(IsFixed ? ResTy : TypeResult());
  if (!Arg.isValid())
    Arg = Builder->Constant(0, ResTy);

  ExpectRParen("unexpected argument in unary expression.");  
  ExprHandle E = Arg.get();
  switch (Kind) {
  case eMacroKind_Neg:
    return Builder->Sub(Builder->Constant(0, E->getWidth()), E);
  case Expr::Not:
    // FIXME: Type check arguments.
    return Builder->Not(E);
  case Expr::SExt:
    // FIXME: Type check arguments.
    return Builder->SExt(E, ResTy);
  case Expr::ZExt:
    // FIXME: Type check arguments.
    return Builder->ZExt(E, ResTy);
  default:
    Error("internal error, unhandled kind.", Name);
    return Builder->Constant(0, ResTy);
  }
}

IntegerResult ParserImpl::ParseIntegerConstant(Expr::Width Type) {
  ExprResult Res = ParseNumber(Type);

  if (!Res.isValid())
    return IntegerResult();

  return cast<ConstantExpr>(Res.get())->getZExtValue(Type);
}

ExprResult ParserImpl::ParseSelectParenExpr(const Token &Name, 
                                            Expr::Width ResTy) {
  // FIXME: Why does this need to be here?
  if (Tok.kind == Token::RParen) {
    Error("unexpected end of arguments.", Name);
    ConsumeRParen();
    return Builder->Constant(0, ResTy);
  }

  ExprResult Cond = ParseExpr(Expr::Bool);
  ExprResult LHS, RHS;
  ParseMatchedBinaryArgs(Name, ResTy, LHS, RHS);
  if (!Cond.isValid() || !LHS.isValid() || !RHS.isValid())
    return Builder->Constant(0, ResTy);
  return Builder->Select(Cond.get(), LHS.get(), RHS.get());
}

ExprResult ParserImpl::ParseExtractParenExpr(const Token &Name,
                                             Expr::Width ResTy) {
  IntegerResult OffsetExpr = ParseIntegerConstant(Expr::Int32);
  ExprResult Child = ParseExpr(TypeResult());

  ExpectRParen("unexpected argument to expression.");

  if (!OffsetExpr.isValid() || !Child.isValid())
    return Builder->Constant(0, ResTy);

  unsigned Offset = (unsigned) OffsetExpr.get();
  if (Offset + ResTy > Child.get()->getWidth()) {
    Error("extract out-of-range of child expression.", Name);
    return Builder->Constant(0, ResTy);
  }

  return Builder->Extract(Child.get(), Offset, ResTy);
}

/// ParseExpr - Parse an expression with the given \arg
/// ExpectedType. \arg ExpectedType can be invalid if the type cannot
/// be inferred from the context.
///
/// expr = false | true
/// expr = <constant>
/// expr = <identifier>
/// expr = [<identifier>:] paren-expr
ExprResult ParserImpl::ParseExpr(TypeResult ExpectedType) {
  // FIXME: Is it right to need to do this here?
  if (Tok.kind == Token::EndOfFile) {
    Error("unexpected end of file.");
    return ExprResult();
  }

  if (Tok.kind == Token::KWFalse || Tok.kind == Token::KWTrue) {
    bool Value = Tok.kind == Token::KWTrue;
    ConsumeToken();
    return ExprResult(Builder->Constant(Value, Expr::Bool));
  }
  
  if (Tok.kind == Token::Number) {
    if (!ExpectedType.isValid()) {
      Error("cannot infer type of number.");
      ConsumeToken();
      return ExprResult();
    }
    
    return ParseNumber(ExpectedType.get());
  }

  const Identifier *Label = 0;
  if (Tok.kind == Token::Identifier) {
    Token LTok = Tok;
    Label = GetOrCreateIdentifier(Tok);
    ConsumeToken();

    if (Tok.kind != Token::Colon) {
      ExprSymTabTy::iterator it = ExprSymTab.find(Label);

      if (it == ExprSymTab.end()) {
        Error("invalid expression label reference.", LTok);
        return ExprResult();
      }

      return it->second;
    }

    ConsumeToken();
    if (ExprSymTab.count(Label)) {
      Error("duplicate expression label definition.", LTok);
      Label = 0;
    }
  }

  Token Start = Tok;
  ExprResult Res = ParseParenExpr(ExpectedType);
  if (!Res.isValid()) {
    // If we know the type, define the identifier just so we don't get
    // use-of-undef errors. 
    // FIXME: Maybe we should let the symbol table map to invalid
    // entries?
    if (Label && ExpectedType.isValid()) {
      ref<Expr> Value = Builder->Constant(0, ExpectedType.get());
      ExprSymTab.insert(std::make_pair(Label, Value));
    }
    return Res;
  } else if (ExpectedType.isValid()) {
    // Type check result.    
    if (Res.get()->getWidth() != ExpectedType.get()) {
      // FIXME: Need more info, and range
      Error("expression has incorrect type.", Start);
      return ExprResult();
    }
  }

  if (Label)
    ExprSymTab.insert(std::make_pair(Label, Res.get()));
  return Res;
}

/// ParseQueryCommand - Parse query command. The lexer should be
/// positioned at the 'query' keyword.
/// 
/// 'query' expressions-list expression [expressions-list [array-list]]
DeclResult ParserImpl::ParseQueryCommand() {
  std::vector<ExprHandle> Constraints;
  std::vector<ExprHandle> Values;
  std::vector<const Array*> Objects;
  ExprResult Res;

  // FIXME: We need a command for this. Or something.
  ExprSymTab.clear();
  VersionSymTab.clear();

  // Reinsert initial array versions.
  // FIXME: Remove this!
  for (std::map<const Identifier*, const ArrayDecl*>::iterator
         it = ArraySymTab.begin(), ie = ArraySymTab.end(); it != ie; ++it) {
    VersionSymTab.insert(std::make_pair(it->second->Name,
                                        UpdateList(it->second->Root, NULL)));
  }


  ConsumeExpectedToken(Token::KWQuery);
  if (Tok.kind != Token::LSquare) {
    Error("malformed query, expected constraint list.");
    SkipUntilRParen();
    return DeclResult();
  }

  ConsumeLSquare();
  // FIXME: Should avoid reading past unbalanced parens here.
  while (Tok.kind != Token::RSquare) {
    if (Tok.kind == Token::EndOfFile) {
      Error("unexpected end of file.");
      Res = ExprResult(Builder->Constant(0, Expr::Bool));
      goto exit;
    }

    ExprResult Constraint = ParseExpr(TypeResult(Expr::Bool));
    if (Constraint.isValid())
      Constraints.push_back(Constraint.get());
  }
  ConsumeRSquare();

  Res = ParseExpr(TypeResult(Expr::Bool));
  if (!Res.isValid()) // Error emitted by ParseExpr.
    Res = ExprResult(Builder->Constant(0, Expr::Bool));

  // Return if there are no optional lists of things to evaluate.
  if (Tok.kind == Token::RParen)
    goto exit;

  if (Tok.kind != Token::LSquare) {
    Error("malformed query, expected expression list.");
    SkipUntilRParen();
    return DeclResult();
  }
  
  ConsumeLSquare();
  // FIXME: Should avoid reading past unbalanced parens here.
  while (Tok.kind != Token::RSquare) {
    if (Tok.kind == Token::EndOfFile) {
      Error("unexpected end of file.");
      goto exit;
    }

    ExprResult Res = ParseExpr(TypeResult());
    if (Res.isValid())
      Values.push_back(Res.get());
  }
  ConsumeRSquare();

  // Return if there are no optional lists of things to evaluate.
  if (Tok.kind == Token::RParen)
    goto exit;

  if (Tok.kind != Token::LSquare) {
    Error("malformed query, expected array list.");
    SkipUntilRParen();
    return DeclResult();
  }

  ConsumeLSquare();
  // FIXME: Should avoid reading past unbalanced parens here.
  while (Tok.kind != Token::RSquare) {
    if (Tok.kind == Token::EndOfFile) {
      Error("unexpected end of file.");
      goto exit;
    }

    // FIXME: Factor out.
    if (Tok.kind != Token::Identifier) {
      Error("unexpected token.");
      ConsumeToken();
      continue;
    }

    Token LTok = Tok;
    const Identifier *Label = GetOrCreateIdentifier(Tok);
//.........这里部分代码省略.........

/// ParseArrayDecl - Parse an array declaration. The lexer should be positioned
/// at the opening 'array'.
///
/// array-declaration = "array" name "[" [ size ] "]" ":" domain "->" range 
///                       "=" array-initializer
/// array-initializer = "symbolic" | "{" { numeric-literal } "}"
DeclResult ParserImpl::ParseArrayDecl() {
  // FIXME: Recovery here is horrible, we need to scan to next decl start or
  // something.
  ConsumeExpectedToken(Token::KWArray);
  
  if (Tok.kind != Token::Identifier) {
    Error("expected identifier token.");
    return DeclResult();
  }

  Token Name = Tok;
  IntegerResult Size;
  TypeResult DomainType;
  TypeResult RangeType;
  std::vector< ref<ConstantExpr> > Values;

  ConsumeToken();
  
  if (Tok.kind != Token::LSquare) {
    Error("expected '['.");
    goto exit;
  }
  ConsumeLSquare();

  if (Tok.kind != Token::RSquare) {
    Size = ParseIntegerConstant(64);
  }
  if (Tok.kind != Token::RSquare) {
    Error("expected ']'.");
    goto exit;
  }
  ConsumeRSquare();
  
  if (Tok.kind != Token::Colon) {
    Error("expected ':'.");
    goto exit;
  }
  ConsumeExpectedToken(Token::Colon);

  DomainType = ParseTypeSpecifier();
  if (Tok.kind != Token::Arrow) {
    Error("expected '->'.");
    goto exit;
  }
  ConsumeExpectedToken(Token::Arrow);

  RangeType = ParseTypeSpecifier();
  if (Tok.kind != Token::Equals) {
    Error("expected '='.");
    goto exit;
  }
  ConsumeExpectedToken(Token::Equals);

  if (Tok.kind == Token::KWSymbolic) {
    ConsumeExpectedToken(Token::KWSymbolic);    
  } else if (Tok.kind == Token::LSquare) {
    ConsumeLSquare();
    while (Tok.kind != Token::RSquare) {
      if (Tok.kind == Token::EndOfFile) {
        Error("unexpected end of file.");
        goto exit;
      }

      ExprResult Res = ParseNumber(RangeType.get());
      if (Res.isValid())
        Values.push_back(cast<ConstantExpr>(Res.get()));
    }
    ConsumeRSquare();
  } else {
    Error("expected 'symbolic' or '['.");
    goto exit;
  }

  // Type check size.
  if (!Size.isValid()) {
    if (Values.empty()) {
      Error("unsized arrays are not yet supported.");
      Size = 1;
    } else {
      Size = Values.size();
    }
  }

  if (!Values.empty()) {
    if (Size.get() != Values.size()) {
      // FIXME: Lame message.
      Error("constant arrays must be completely specified.");
      Values.clear();
    }

    // for (unsigned i = 0; i != Size.get(); ++i) {
    // TODO: Check: Must be constant expression.
    //}
  }
//.........这里部分代码省略.........

ExprResult ParserImpl::ParseAnyReadParenExpr(const Token &Name,
                                             unsigned Kind,
                                             Expr::Width ResTy) {
  NumberOrExprResult Index = ParseNumberOrExpr();
  VersionResult Array = ParseVersionSpecifier();
  ExpectRParen("unexpected argument in read expression.");
  
  if (!Array.isValid())
    return Builder->Constant(0, ResTy);

  // FIXME: Need generic way to get array width. Needs to work with
  // anonymous arrays.
  Expr::Width ArrayDomainType = Expr::Int32;
  Expr::Width ArrayRangeType = Expr::Int8;

  // Coerce number to correct type.
  ExprResult IndexExpr;
  if (Index.isNumber())
    IndexExpr = ParseNumberToken(ArrayDomainType, Index.getNumber());
  else
    IndexExpr = Index.getExpr();
  
  if (!IndexExpr.isValid())
    return Builder->Constant(0, ResTy);
  else if (IndexExpr.get()->getWidth() != ArrayDomainType) {
    Error("index width does not match array domain.");
    return Builder->Constant(0, ResTy);
  }

  // FIXME: Check range width.

  switch (Kind) {
  default:
    assert(0 && "Invalid kind.");
    return Builder->Constant(0, ResTy);
  case eMacroKind_ReadLSB:
  case eMacroKind_ReadMSB: {
    unsigned NumReads = ResTy / ArrayRangeType;
    if (ResTy != NumReads*ArrayRangeType) {
      Error("invalid ordered read (not multiple of range type).", Name);
      return Builder->Constant(0, ResTy);
    }
    std::vector<ExprHandle> Kids(NumReads);
    ExprHandle Index = IndexExpr.get();
    for (unsigned i=0; i != NumReads; ++i) {
      // FIXME: We rely on folding here to not complicate things to where the
      // Read macro pattern fails to match.
      ExprHandle OffsetIndex = Index;
      if (i)
        OffsetIndex = AddExpr::create(OffsetIndex,
                                      Builder->Constant(i, ArrayDomainType));
      Kids[i] = Builder->Read(Array.get(), OffsetIndex);
    }
    if (Kind == eMacroKind_ReadLSB)
      std::reverse(Kids.begin(), Kids.end());
    // FIXME: Use builder!
    return ConcatExpr::createN(NumReads, &Kids[0]);
  }
  case Expr::Read:
    return Builder->Read(Array.get(), IndexExpr.get());
  }
}