Re: compiler error in GNAT 3.14a1

[Preben Randhol <randhol+valid_for_reply_from_news@pvv.org>]

On 2004-02-12, Vincent Smeets <Nobody@No.SPAM.org> wrote:
> Hallo,
>
> I have found a compiler error in GNAT 3.14a1.
>
> I have a record D with two components E and F. The layout of the record is
> defined by a representation clause. By a typing error, I defined the
> bit-range to be zero (0 .. 0). See record D2. The compiler compiles the file
> without an error or warning and changes the layout of the record.
>
> I would at least acpect a warning from the compiler.
>
>
>
> azha:592$ cat a.ads
> package A is
>
>    type B is range 0 .. 255;
>    for B'Size use 8;
>
>    type C is array (Integer range 1 .. 4) of B;
>    for C'Component_Size use 8;
>
>    type D is
>       record
>          E : C;
>          F : B;
>       end record;
>    for D use
>       record
>          E at 0 range 0 .. 4 * 8 - 1;
>          F at 4 range 0 ..     8 - 1;
>       end record;
>
>    type D2 is
>       record
>          E : C;
>          F : B;
>       end record;
>    for D2 use
>       record
>          E at 0 range 0 .. 0 * 8 - 1;
>          F at 4 range 0 ..     8 - 1;
>       end record;
>
> end A;
> azha:593$ gcc -c -gnatR2 -gnatv -gnatwa a.ads
>
> GNAT 3.14a1 (20010503) Copyright 1992-2001 Free Software Foundation, Inc.
>
> Compiling: a.ads (source file time stamp: 2004-02-12 08:59:47)
>  31 lines: No errors
>
> Representation information for unit A (spec)
> --------------------------------------------
>
> for B'Size use 8;
> for B'Alignment use 1;
>
> for C'Size use 32;
> for C'Alignment use 1;
> for C'Component_Size use 8;
>
> for D'Size use 40;
> for D'Alignment use 1;
> for D use record
>    E at 0 range  0 .. 31;
>    F at 4 range  0 ..  7;
> end record;
>
> for D2'Size use 72;
> for D2'Alignment use 1;
> for D2 use record
>    E at 5 range  0 .. 31;
>    F at 4 range  0 ..  7;
> end record;
> azha:594$
>
>

Using Gnat 3.15p I get:


% gnatmake -c -gnatR2 -gnatv -gnatwa a.ads
gnatgcc -c -gnatR2 -gnatv -gnatwa a.ads

GNAT 3.15p  (20020523) Copyright 1992-2002 Free Software Foundation, Inc.

Compiling: a.ads (source file time stamp: 2004-02-12 12:09:21)

    27.          E at 0 range 0 .. 0 * 8 - 1;
                                         |
        >>> size for "E" too small, minimum allowed is 32

 32 lines: 1 error

Representation information for unit A (spec)
--------------------------------------------

for B'Size use 8;
for B'Alignment use 1;

for C'Size use 32;
for C'Alignment use 1;
for C'Component_Size use 8;

for D'Size use 40;
for D'Alignment use 1;
for D use record
   E at 0 range  0 .. 31;
   F at 4 range  0 ..  7;
end record;

for D2'Size use 72;
for D2'Alignment use 1;
for D2 use record
   E at 5 range  0 .. 31;
   F at 4 range  0 ..  7;
end record;
gnatmake: "a.ads" compilation error


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