RE: [fpc-devel] Optimization error causes pyacc and plex to fail

2005-01-01 Thread Lee, John
Know that there have been problems with some optimisations (Jonas has fixed
some), so maybe this is reason. Regards John   

-Original Message-
From: [EMAIL PROTECTED]
To: fpc-devel@lists.freepascal.org
Sent: 01/01/2005 06:49 p.m.
Subject: [fpc-devel] Optimization error causes pyacc and plex to fail

Can't seem to get bug submission to work so I'm sending this here.
The 1.9.x distributed binaries of plex and pyacc both fail, as well as
any created from a 1.9.5 source snapshot. plex ends normally but only
creates 2 states. pyacc fails with a RTE 216 on a move in procedure
setunion of yaccbase. The makefile compiles these programs with the
-OG2p3 option. Changing this to either -Og2p3 or -OG1p3 and they both
work correctly. I am using unmodified versions of both programs so am
only attaching the output of each scenario. Feel free to contact me if
you need anything else.
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[fpc-devel] Optimization error causes pyacc and plex to fail

2005-01-01 Thread DSTRODT



Can't seem to get bug submission to work so I'm sending this here.
The 1.9.x distributed binaries of plex and pyacc both fail, as well as any 
created from a 1.9.5 source snapshot. plex ends normally but only creates 2 
states. pyacc fails with a RTE 216 on a move in procedure setunion of yaccbase. 
The makefile compiles these programs with the -OG2p3 option. Changing this to 
either -Og2p3 or -OG1p3 and they both work correctly. I am using unmodified 
versions of both programs so am only attaching the output of each scenario. Feel 
free to contact me if you need anything else.
(* plex compiled with -OG2p3 *)
>plex -v -o xrlex.l
TP Lex Version 4.1a [April 2000], Copyright (c) 1990-2000 Albert Graef
parse ... DFA construction ... DFA optimization ... code generation ... DONE
169 lines, 44 rules, 173/1200 p, 2/600 s, 0/1200 t.
(see xrlex.lst for more information)

(* plex compiled with -Og2p3 or -OG1p3 *)
>plex -v -o xrlex.l
TP Lex Version 4.1a [April 2000], Copyright (c) 1990-2000 Albert Graef
parse ... DFA construction ... DFA optimization ... code generation ... DONE
169 lines, 44 rules, 173/1200 p, 61/600 s, 102/1200 t.
(see xrlex.lst for more information)

(* pyacc compiled with -OG2p3 *)
>pyacc -v xrpars.y
TP Yacc Version 4.1a [April 2000], Copyright (c) 1990-2000 Albert Graef
parse ... sort ... closures ... Runtime error 216 at $0040CA1C
  $0040CA1C  MOVE,  line 76 of F:/FPCDevel/SrcCVS123104/fpc/rtl/i386/i386.inc
  $00407FA5  SETUNION,  line 349 of YaccBase.pas
  $0040208B  CLOSURES,  line 94 of YaccClos.pas
  $00407452  GENERATE_PARSER,  line 580 of YaccSem.pas
  $00409B20  YYACTION,  line 250 of pyacc.pas
  $00409716  YYPARSE,  line 2079 of pyacc.pas
  $0040B5F5  main,  line 2479 of pyacc.pas

(* pyacc compiled with -Og2p3 or -OG1p3 *)
>pyacc -v xrpars.y
TP Yacc Version 4.1a [April 2000], Copyright (c) 1990-2000 Albert Graef
parse ... sort ... closures ... first sets ... LR0 set ... lookaheads ... 
code generation ... DONE
1396 lines, 433/900 rules, 691/1200 s, 3334/9600 i, 3138/9600 t, 487/1200 r.
1 shift/reduce conflicts.
(see xrpars.lst for more information)
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Re: [fpc-devel] compiler bug?

2005-01-01 Thread Nico Aragón
[merged responses to two messages]

El Sábado, 1 de Enero de 2005 06:54, DrDiettrich escribiste:
> > ¡Serás melón!
>
> Could you please help me to improve my rudimentary Spanish? ;-)

http://hotel.jp-guide.net/job/point/melon.jpg

> (Eierkopf? ;-)

My rudimentary... I meant my non-existent... whatever :-)

> > ¡Feliz año, torpedo! :-)
>
> (Blindgänger? ;-)

It's the same in English.

> Feliz año, Bonne Année, Happy New Year, Gelukkige Nieuwe Jaar, und ein
> Gutes Neues Jahr allerseits!

All of that! :-)

*

El Sábado, 1 de Enero de 2005 06:29, DrDiettrich escribiste:
> Nico Aragón wrote:
> > > > IIRC, any non-zero value is evaluated as "True" for a Boolean
> > > > variable.
> > >
> > > You should not guess about any implementation.
> >
> > I don't. Do I?
>
> Yes, you do. 

No, I don't. Maybe you're confusing me with Jesús? If you read my last answer 
to José Manuel, you'll see that I say exactly the opposite. So I can't agree 
more with the rest of your post.

-- 
saludos,

Nico Aragón
http://espira.net/nico/

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Re: [fpc-devel] compiler bug?

2005-01-01 Thread DrDiettrich
Nico Aragón wrote:
 
> > > IIRC, any non-zero value is evaluated as "True" for a Boolean variable.
> >
> > You should not guess about any implementation.
> 
> I don't. Do I?

Yes, you do. How can you know what bit pattern is stored in a boolean
variable? Using typecasts may result in silent type conversion,
returning something different from the really stored pattern.

The boolean data type is distinct from other data types, so that it's
wild guessing that every compiler and compiler version will treat
boolean values and variables in the same way, as observed when using a
specific version of an specific compiler.

For completeness: Many people also consider ByteBool etc. as being
"boolean". These types have been made compatible with boolean
*intentionally*, with the documented behaviour that any non-zero value
will evaluate to True, under circumstances. But you may test yourself
what will happen when you compare such a variable with an non-boolean
value - it's not perfectly specified when the nonzero=true evaluation
will be effective. Try this with various compilers:

var b: ByteBool;
...
case b of
True: ...
False: ...
42: ...
else ...
end;

It's unspecified which compiler will accept the True and False constants
here at all...

DoDi



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Re: [fpc-devel] compiler bug?

2005-01-01 Thread DrDiettrich
Nico Aragón wrote:
 
> ¡Serás melón!

Could you please help me to improve my rudimentary Spanish? ;-)
(Eierkopf? ;-)
 
> ¡Feliz año, torpedo! :-)
(Blindgänger? ;-)

Feliz año, Bonne Année, Happy New Year, Gelukkige Nieuwe Jaar, und ein
Gutes Neues Jahr allerseits!

DoDi



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[fpc-devel] Portability Standards

2005-01-01 Thread DrDiettrich
In the meantime I downloaded the Abbrevia package from SourceForge, and
came across several unpleasent constructs. Please let me introduce my
preferred programming model for portable code.

1) Target Dependencies
I don't accept any OS or machine specific conditional compilation in
code, except in dedicated units. In Abbrevia the same fixes occur in
various places in the code, instead of in a dedicated OS specific
procedure. Such a procedure exists, but unfortunately only in the
unpatched form :-(
Also compiler specific conditionals should be used only where absolutely
necessary (local options, syntax differences...).

2) Code Checks
It should be possible to check code for compilation on other platforms.
This requires that target specific code can be compiled on any host,
somehow. Consequently it must be possible to override the compiler
generated symbols that describe the environment.

3) Standard Units
Portable code shall use standard procedures and units for target
specific actions. This requires the definition, implementation, and
consequential use of one or more standard units for:
- Machine specific data types and procedures (endianness...)
- OS specific data types and procedures
- C and POSIX specific data types (for code ported from GNU/C)
Then it should be clear which portable data types and procedures should
be taken from which unit. It also should be easier to determine which
procedures need special considerations in portable code, from the
defined data types and procedures in these units.

It's not necessary that everybody follows these principles, but I will
do so in my own published portable code. Otherwise I can continue to
write my code for Delphi, and let it to somebody else to port that code
to e.g. FPC.

In the simplest case these units will have an unconditional interface
part, the target specific data type declarations and the implementation
part can be included conditionally from the appropriate locations. For
testing purposes fake units or code sections can contain the OS specific
procedure declarations, with empty bodies. This way I could verify that
my changes to the main stream code would not break the code for other
environments, due to the use of not yet ported constants or data types
etc.

This model has one disadvantage, in so far as complex procedures with
small embedded platform specific code could no more be checked, because
it often was impossible to determine the impact of changes to local
variables etc. in the conditionally excluded code. It also was and is
impossible to automatically verify that the conditional sections really
are implemented for every target!

In another implementation of a target independent library I defined
portable classes with standardized methods. These virtual methods were
almost abstract in the base class, so that they had to be overridden in
every derived class. In the initialization section of the unit the
appropriate class was created and assigned to the according variable,
based on the actual or desired target environment. Of course this
approach has the disadvantage of increasing runtime (how much?), due to
the virtual method calls. Nonetheless I think that in many cases the
difference from the traditional method will not be noticeable, due to
the (unknown, long?) runtime spent in the embedded OS calls.

The best compromise might be a mix of both methods. The interface can be
fully procedural, and objects with virtual methods are used only in the
implementation part, and only when this approach makes sense. Perhaps
somebody finds another way to achieve the same goal, with less
disadvantages?


I'm willing to demonstrate my ideas in a redesign and extension of
Abbrevia, so that we have a concreter base for further discussions. But
before starting with that work I would like to hear some encouraging 
opinions or suggestions.

DoDi


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Re: [fpc-devel] Interface to compressed files and archives

2005-01-01 Thread DrDiettrich
[EMAIL PROTECTED] wrote:

> > E.g.: gzip.xyz, is this based on a gzip unit or a gzip variable or...
> 
> Does this matter to you ?
> 
> Normally one never uses a fully qualified identifier.

And that can become a problem, when a variable and a unit has the same
name. That's why I do not only prefer to prefix type names with "T", but
also unit names with "u", form (unit) names with "f" etc. As prefixes
for specific kinds of units seem to be in use by other people as well,
why not prefix all units?

> Only when a possible name conflict exists, which
> - Should be very rare, and avoided in the first place.
> - In such cases it will be obvious from the context.

Okay, name clashes between unit and variable names should be detectable
easily. But then a decision has to be made, which of both names should
stay unchanged, and which one to decorate. My preference then is to
decorate the unit names, because these occur less frequently in source
code, and almost only in obvious Uses clauses.

I know that my private prefix style is a bit uncommon, as is my coding
style (indentation...). In shareable contributions I'm willing to follow
the more widely accepted standards, of course :-)

DoDi



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Re: [fpc-devel] compiler bug?

2005-01-01 Thread Nico Aragón
El Sábado, 1 de Enero de 2005 09:06, Jose Manuel escribiste:
> So i think. I think Ord(TRUE), Succ(FALSE), etc. are valid Standard and
> Extended Pascal expressions, as well as the behaviour of a declarion of

As far as I know:

  Ord(True) > Ord(False) = True
  Succ(False) = True

...are not only legal but also mandatory in the standard. But that doesn't 
mean anything. You can implement Ord and Succ to return that values for 
booleans no matter how you implemented the type.

> type TBoolArray = array[boolean] of ... is neatly defined in the very
> language. (At least in Modula-2, that enumeration is part of the standard,
> so it's a language feature and not compiler implementation dependant).

It's possible to implement the boolean type as an enumeration and still 
implement the boolean evaluation as "<> 0". I'm pretty sure to have seen this 
in some specification, I just can't remember in which right now :-)

-- 
saludos,

Nico Aragón
http://espira.net/nico/

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RE: [fpc-devel] compiler bug?

2005-01-01 Thread Jose Manuel

> 3: the PASCAL way
>   boolean is a totally seperate type from integer types so the compiler
> knows whether you mean logial or bitwise operations. I don't know if false

That's the point. :-)

> and true having ordinal values of 0 and 1 is part of a standard or a
> borlandism but im pretty sure its what all pascal compilers anyone cares
> about do.

So i think. I think Ord(TRUE), Succ(FALSE), etc. are valid Standard and
Extended Pascal expressions, as well as the behaviour of a declarion of type
TBoolArray = array[boolean] of ... is neatly defined in the very language.
(At least in Modula-2, that enumeration is part of the standard, so it's a
language feature and not compiler implementation dependant).

JMR



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