[M3devel] pre-report

[Antony Hosking]

I’m trying to get a sense for what the correct behavior of the compiler should be in this case. I think that the passing of the unaligned ARRAY OF CHAR as an open array parameter should be disallowed.  There is no way to communicate the alignment in the dope vector built for the open array formal.

In which case, the fix is the following patch to Formal.m3, disallowing a formal parameter for a 

*** Formal.m3.~1.16.~	Wed Sep  5 11:03:31 2012
--- Formal.m3	Mon Sep 10 12:07:46 2012
***************
*** 356,361 ****
--- 356,362 ----
              ELSIF Type.IsEqual (t, te, NIL) THEN
                Expr.NeedsAddress (e);
              ELSIF ArrayType.Split (t, index, elt)
+               AND ArrayType.Split (te, index, elt)
                AND Type.IsAssignable (t, te) THEN
                Expr.NeedsAddress (e);
              ELSE


Can anyone think if this will break any existing code?  I can’t think of anything where it will break (assigning something that does not have array type to a formal parameter of array type).

On Sep 10, 2012, at 3:41 AM, Dragiša Durić <dragisha at m3w.org> wrote:

> MODULE TestCase EXPORTS Main;
> 
> PROCEDURE Do(VAR b: ARRAY OF CHAR) =
>  BEGIN
>  END Do;
> 
> VAR
>  arg: RECORD
>    a: BITS 1 FOR BOOLEAN; (* case 2 is this, case 1 is: comment a out :) *)
>    b: BITS 24 FOR ARRAY [0..2] OF CHAR;
>  END;
> 
> BEGIN
>  Do(arg.b);
> END TestCase.
> 
> --
> Divided by a common language
> 
> Dragiša Durić
> dragisha at m3w.org
> 
> 
> 
> 
> On Sep 10, 2012, at 4:03 AM, Antony Hosking wrote:
> 
>> What’s the source code?
>> Testcase please...
>> 
>> On Sep 8, 2012, at 3:23 AM, Dragiša Durić <dragisha at m3w.org> wrote:
>> 
>>> Just got this, many times in a row :)
>>> 
>>> ===
>>> % cm3
>>> --- building in ../AMD64_DARWIN ---
>>> 
>>> new source -> compiling Descriptors.m3
>>> 
>>> 
>>> ***
>>> *** runtime error:
>>> ***    <*ASSERT*> failed.
>>> ***    file "../src/values/Formal.m3", line 689
>>> ***
>>> 
>>> zsh: abort      cm3
>>> 
>>> 
>>> % cm3 -?
>>> Critical Mass Modula-3 version d5.9.0
>>> last updated: 2010-07-21
>>> compiled: 2011-03-23 04:04:18
>>> configuration: /usr/local/cm3/bin/cm3.cfg
>>> host: AMD64_DARWIN
>>> target: AMD64_DARWIN
>>> 
>>> --
>>> Divided by a common language
>>> 
>>> Dragiša Durić
>>> dragisha at m3w.org
>>> 
>>> 
>>> 
>>> 
>> 
>