bug#32644: bytevector bug

bug#32644: bytevector bug

[Stefan Israelsson Tampe]

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Hi,

The code velow does not compile when the define-inlinable of id is active.
If in stead
id defined by define is used it all compiles just fine.

Tested on latest tar ball for guile 2.4
-------------------------------------------
(use-modules (rnrs bytevectors))

(define-inlinable (id x) x)
;(define (id x) x)
(define-syntax-rule (mkcrc crc_hqx high xor mask)
  (define (crc_hqx data value)
       (let ((n (bytevector-length data))
     (d data))
(let lp ((i 0) (v value))
   (if (< i n)
       (let ((b (id (bytevector-u8-ref d i))))
(let lp2 ((j 0) (x 1) (v v))
   (if (> j -8)
       (let ((bit   (ash (logand x b) j))
     (hbit  (logand v high)))
(if (= hbit 0)
     (lp2 (- j 1) (ash x 1) (logior bit (ash v 1)))
     (lp2 (- j 1) (ash x 1) (logxor
     xor
     (logand mask
     (logior
      bit
      (ash v 1)))))))
       (lp (+ i 1) v))))
       v)))))

(mkcrc crc_hqx #x8000     #x1021     #xffff)
(mkcrc crc32   #x80000000 #x04c11db7 #xffffffff)

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bug#32644: bytevector bug

[Mark H Weaver]

Stefan Israelsson Tampe <stefan.itampe@gmail.com> writes:

> The code velow does not compile when the define-inlinable of id is active. If in stead
> id defined by define is used it all compiles just fine.
>
> Tested on latest tar ball for guile 2.4

Did you mean to write guile 2.2.4?

      Mark


> -------------------------------------------
> (use-modules (rnrs bytevectors))
>
> (define-inlinable (id x) x)
> ;(define (id x) x)
> (define-syntax-rule (mkcrc crc_hqx high xor mask)
>   (define (crc_hqx data value)
>        (let ((n (bytevector-length data))
>      (d data))
> (let lp ((i 0) (v value))
>    (if (< i n)
>        (let ((b (id (bytevector-u8-ref d i))))
> (let lp2 ((j 0) (x 1) (v v))
>    (if (> j -8)
>        (let ((bit   (ash (logand x b) j))
>      (hbit  (logand v high)))
> (if (= hbit 0)
>      (lp2 (- j 1) (ash x 1) (logior bit (ash v 1)))
>      (lp2 (- j 1) (ash x 1) (logxor
>      xor
>      (logand mask
>      (logior
>       bit
>       (ash v 1)))))))
>        (lp (+ i 1) v))))
>        v)))))
>
> (mkcrc crc_hqx #x8000     #x1021     #xffff)
> (mkcrc crc32   #x80000000 #x04c11db7 #xffffffff)

bug#32644: bytevector bug

[Stefan Israelsson Tampe]

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I managed to get it to compile on the latest lightning branch as of
2018-09-14

On Thu, Sep 6, 2018 at 7:28 PM Mark H Weaver <mhw@netris.org> wrote:

> Stefan Israelsson Tampe <stefan.itampe@gmail.com> writes:
>
> > The code velow does not compile when the define-inlinable of id is
> active. If in stead
> > id defined by define is used it all compiles just fine.
> >
> > Tested on latest tar ball for guile 2.4
>
> Did you mean to write guile 2.2.4?
>
>       Mark
>
>
> > -------------------------------------------
> > (use-modules (rnrs bytevectors))
> >
> > (define-inlinable (id x) x)
> > ;(define (id x) x)
> > (define-syntax-rule (mkcrc crc_hqx high xor mask)
> >   (define (crc_hqx data value)
> >        (let ((n (bytevector-length data))
> >      (d data))
> > (let lp ((i 0) (v value))
> >    (if (< i n)
> >        (let ((b (id (bytevector-u8-ref d i))))
> > (let lp2 ((j 0) (x 1) (v v))
> >    (if (> j -8)
> >        (let ((bit   (ash (logand x b) j))
> >      (hbit  (logand v high)))
> > (if (= hbit 0)
> >      (lp2 (- j 1) (ash x 1) (logior bit (ash v 1)))
> >      (lp2 (- j 1) (ash x 1) (logxor
> >      xor
> >      (logand mask
> >      (logior
> >       bit
> >       (ash v 1)))))))
> >        (lp (+ i 1) v))))
> >        v)))))
> >
> > (mkcrc crc_hqx #x8000     #x1021     #xffff)
> > (mkcrc crc32   #x80000000 #x04c11db7 #xffffffff)
>

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bug#32644: bytevector bug

[Mark H Weaver]

Stefan Israelsson Tampe <stefan.itampe@gmail.com> writes:
> The code velow does not compile when the define-inlinable of id is active. If in stead
> id defined by define is used it all compiles just fine.

The problem was that, in some cases, the type inferrer would call 'ash'
with (- 1 (expt 2 64)) as the second argument during compilation.  The
implementation of 'ash' would raise an exception unless its second
argument (the shift count) fits in a C 'long'.

This is fixed in commit 011aec7e240ef987931548d90c53e6692c85d01c on the
stable-2.2 branch.  That commit extends 'ash' and 'round-ash' to
gracefully handle several cases where the shift count is too large to
fit in a 'long'.

Thanks for the report.

      Mark