Critical Mass Modula-3: m3tk/src/sem/M3CBitSize.m3

m3tk/src/sem/M3CBitSize.m3

MODULE M3CBitSize;

************************************************************************* Copyright (C) Olivetti 1989 All Rights reserved Use and copy of this software and preparation of derivative works based upon this software are permitted to any person, provided this same copyright notice and the following Olivetti warranty disclaimer are included in any copy of the software or any modification thereof or derivative work therefrom made by any person. This software is made available AS IS and Olivetti disclaims all warranties with respect to this software, whether expressed or implied under any law, including all implied warranties of merchantibility and fitness for any purpose. In no event shall Olivetti be liable for any damages whatsoever resulting from loss of use, data or profits or otherwise arising out of or in connection with the use or performance of this software. *************************************************************************

IMPORT AST, M3AST_AS, M3AST_SM;

IMPORT M3AST_AS_F, M3AST_SM_F;

IMPORT M3ASTNext, M3CTypesMisc, M3COrdinal;
IMPORT M3CBackEnd;

Only the back-end knows how to compute these attributes. What we do here is ensure that the attributes of dependent types are computed before asking it to compute a size.

EXCEPTION UnsetComponent;

VAR
  proto_object_type_g: M3AST_AS.Object_type := NIL;

PROCEDURE Set(an: AST.NODE) RAISES {}=
  BEGIN
    TYPECASE an OF
    | M3AST_AS.TYPE_SPEC(ts) =>
        TRY
          Eval(ts);
        EXCEPT
        | UnsetComponent =>
            (* leave unset *)
        END;
    ELSE
    END; (* if *)
  END Set;

PROCEDURE Eval(ts: M3AST_SM.TYPE_SPEC_UNSET) RAISES {UnsetComponent}=
  VAR
    componentType: M3AST_SM.TYPE_SPEC_UNSET;
  BEGIN
    IF ts = NIL THEN RAISE UnsetComponent END;

    IF ts.sm_bitsize > 0 THEN RETURN END;

    TYPECASE ts OF
    | M3AST_AS.Record_type(recordType) =>
        VAR
          iter := M3ASTNext.NewIterField(recordType.as_fields_s);
          fieldId: M3AST_AS.Field_id;
        BEGIN
          WHILE M3ASTNext.Field(iter, fieldId) DO
            Eval(fieldId.sm_type_spec);
          END; (* while *)
        END;

    | M3AST_AS.Object_type(objectType) =>
        (* a reference type, but we compute the referent size/align also;
           but we need to prepare for legal recursion, so we set the
           size on the object first (using an empty prototype object). *)
        VAR
          iter := M3ASTNext.NewIterField(objectType.as_fields_s);
          fieldId: M3AST_AS.Field_id;
        BEGIN
          IF proto_object_type_g = NIL THEN
            proto_object_type_g := NEW(M3AST_AS.Object_type).init();
            M3CBackEnd.BitSizeAndAlign(proto_object_type_g);
          END;
          objectType.sm_bitsize := proto_object_type_g.sm_bitsize;
          objectType.sm_align := proto_object_type_g.sm_align;
          WHILE M3ASTNext.Field(iter, fieldId) DO
            Eval(fieldId.sm_type_spec);
          END; (* while *)
        END;

    | M3AST_AS.Array_type(arrayType) =>
        VAR
          element, index: M3AST_SM.TYPE_SPEC_UNSET;
          isopen: BOOLEAN;
        BEGIN
          IF M3ASTNext.Array(arrayType, element, isopen, index) THEN END;
          IF NOT isopen THEN Eval(index) END;
          Eval(element);
        END;

    | M3AST_AS.Packed_type(packedType) =>
        CheckExp_value(packedType.as_exp);
        CheckOrdinal(packedType.as_exp.sm_exp_type_spec, FALSE);
        M3CTypesMisc.GetTYPE_SPECFromM3TYPE(
            packedType.as_type, componentType);
        Eval(componentType);

    | M3AST_AS.Set_type(setType) =>
        M3CTypesMisc.GetTYPE_SPECFromM3TYPE(
            setType.as_type, componentType);
        Eval(componentType);

    | M3AST_AS.Subrange_type(subrangeType) =>
        VAR
          range := subrangeType.as_range;
        BEGIN
          CheckExp_value(range.as_exp1);
          CheckOrdinal(range.as_exp1.sm_exp_type_spec, TRUE);
          CheckExp_value(range.as_exp2);
          CheckOrdinal(range.as_exp2.sm_exp_type_spec, TRUE);
        END;

    | M3AST_SM.Any_type, M3AST_SM.Type_type =>
        RAISE UnsetComponent;

    ELSE (* other primitive types *)
    END; (* case *)

    M3CBackEnd.BitSizeAndAlign(ts);
  END Eval;

<*INLINE*> PROCEDURE CheckExp_value(e: M3AST_AS.EXP) RAISES {UnsetComponent}=
  BEGIN
    IF e.sm_exp_value = NIL THEN RAISE UnsetComponent END;
  END CheckExp_value;

PROCEDURE CheckOrdinal(
    ts: M3AST_SM.TYPE_SPEC_UNSET;
    enumOk: BOOLEAN)
    RAISES {UnsetComponent}=
  VAR
    baseType: M3AST_SM.TYPE_SPEC_UNSET;
  BEGIN
    IF M3COrdinal.Is(ts, baseType) THEN
      TYPECASE baseType OF
      | NULL =>
      | M3AST_AS.INT_TYPE =>
          RETURN;
      | M3AST_AS.WideChar_type,
        M3AST_AS.Enumeration_type =>
          IF enumOk THEN RETURN END;
      ELSE
      END;
    END;
    RAISE UnsetComponent;
  END CheckOrdinal;

BEGIN
END M3CBitSize.