l...@gnu.org (Ludovic Courtès) writes:
> Reviving the discussion, as we’ve been discussing this at the GHM, and
> some people would really like to see it happen. :-)
Great! Any summary of the discussion, for those of us who couldn't make
it there?
> ni...@lysator.liu.se (Niels Möller) skribis:
>
>> To try that out, I'm working with a slightly patched guile:
>
> Do you still have the patch around?
I'm attaching a patch from I tree I have around, without reading it
carefully. I'm not sure this is the latest version I worked with. Maybe
it's of some use.
>> 1. The header file libguile.h. As far as I understand, this is a public
>> header file and it's use of <gmp.h> means that the public guile ABI
>> depends on gmp.
>
> The problem is that there’s a public API dealing with mpz_t:
Exactly. To me, that seems like a potentially hairy problem to get
right.
> SCM_API void scm_to_mpz (SCM x, mpz_t rop);
> SCM_API SCM scm_from_mpz (mpz_t rop);
>
> So, when mini-gmp is used, a <gmp.h> header should be installed as well,
> say under <libguile/mini-gmp.h>. WDYT?
Maybe it would make sense with a level of indirection. User's could
include libguile/bignum.h, which would in turn include either mini-gmp.h
or the real gmp.h, depending on how guile was configured. Users may also
need some way of figuring out if they need to link with -lgmp or not.
>> Since mini-gmp is not binary compatible,
>
> I don’t think there’s a problem, because only mpz_t objects appear in
> the API, and they’re pointers.
mpz_t is a typedef, which is a single element array of a semi-internal
struct. So when you declare
mpz_t x;
you are really declaring a struct, not a pointer (and then the array
type automatically "decays" to a pointer when passed as a function
argument).
But it's likely that mini-gmp will use the same size of that struct. And
even the same layout. I think the main ABI incompatibilities are that
1. symbol names, as seen by the linker, are different. With gmp, mpz_foo
is a name mangling #define, and the real name is ___gmpz_foo.
mini-gmp doesn't do that.
2. mp_limb_t may be of different size: With mini-gmp, it's always
unsigned long, with gmp it's unsigned long long on some platforms
(notably 64-bit windows, I think).
Hmm, or if you're saying that the use of mpz_t in guile's public API is
pointers only, that that might make things a little simpler. But things
will still break badly if the user's code is linked with gmp and guile
uses mini-gmp, or vice versa.
>> 4. mini-gmp has no mp_set_memory_functions.
That's added now, with the subtle difference that mini-gmp doesn't pass
a valid size for the old_size argument for the free and realloc
functions. I don't think guile depends on that feature.
Please also note that the most recent version of mini-gmp is now the one
included in the main gmp repo.
diff --git a/configure.ac b/configure.ac
index a32ff4b..089dfbe 100644
--- a/configure.ac
+++ b/configure.ac
@@ -146,6 +146,10 @@ AC_ARG_ENABLE(regex,
[ --disable-regex omit regular expression interfaces],,
enable_regex=yes)
+AC_ARG_ENABLE(gmp,
+ [ --disable-gmp omit high performance bignums],,
+ enable_gmp=yes)
+
AC_ARG_ENABLE([deprecated],
AS_HELP_STRING([--disable-deprecated],[omit deprecated features]))
@@ -869,15 +873,20 @@ fi
AC_CACHE_SAVE
dnl GMP tests
+if test "x$enable_gmp" != xno ; then
AC_LIB_HAVE_LINKFLAGS([gmp],
[],
[#include <gmp.h>],
[mpz_import (0, 0, 0, 0, 0, 0, 0);])
if test "x$HAVE_LIBGMP" != "xyes"; then
- AC_MSG_ERROR([GNU MP 4.1 or greater not found, see README])
+ AC_MSG_NOTICE([GNU MP 4.1 or greater not found, see README])
+ enable_gmp=no
+fi
+fi
+if test "x$enable_gmp" = xno ; then
+ AC_LIBOBJ([mini-gmp])
fi
-
dnl GNU libunistring is checked for by Gnulib's `libunistring' module.
if test "x$LTLIBUNISTRING" = "x"; then
AC_MSG_ERROR([GNU libunistring is required, please install it.])
@@ -1253,7 +1262,7 @@ main (int argc, char **argv)
# Boehm's GC library
#
#--------------------------------------------------------------------
-PKG_CHECK_MODULES([BDW_GC], [bdw-gc])
+# PKG_CHECK_MODULES([BDW_GC], [bdw-gc])
save_LIBS="$LIBS"
LIBS="$BDW_GC_LIBS $LIBS"
diff --git a/libguile.h b/libguile.h
index 7ac98a5..457dd66 100644
--- a/libguile.h
+++ b/libguile.h
@@ -22,8 +22,11 @@
/* This needs to be included outside of the extern "C" block.
*/
+#if HAVE_LIBGMP
#include <gmp.h>
-
+#else
+#include "libguile/mini-gmp.h"
+#endif
#ifdef __cplusplus
extern "C" {
#endif
diff --git a/libguile/bytevectors.c b/libguile/bytevectors.c
index 811e8d8..240e457 100644
--- a/libguile/bytevectors.c
+++ b/libguile/bytevectors.c
@@ -24,7 +24,11 @@
#include <alloca.h>
#include <assert.h>
+#if HAVE_LIBGMP
#include <gmp.h>
+#else
+#include "mini-gmp.h"
+#endif
#include "libguile/_scm.h"
#include "libguile/extensions.h"
diff --git a/libguile/init.c b/libguile/init.c
index 35ab856..bb79422 100644
--- a/libguile/init.c
+++ b/libguile/init.c
@@ -29,7 +29,11 @@
#include <stdio.h>
#include <sys/stat.h>
#include <fcntl.h>
+#if HAVE_LIBGMP
#include <gmp.h>
+#else
+#include "mini-gmp.h"
+#endif
#include "libguile/_scm.h"
diff --git a/libguile/numbers.h b/libguile/numbers.h
index b7bcfe4..166f222 100644
--- a/libguile/numbers.h
+++ b/libguile/numbers.h
@@ -22,9 +22,11 @@
*/
-
+#ifdef HAVE_LIBGMP
#include <gmp.h>
-
+#else
+#include "mini-gmp.h"
+#endif
#include "libguile/__scm.h"
#include "libguile/print.h"
diff --git a/libguile/random.c b/libguile/random.c
index 8bc0d87..c216245 100644
--- a/libguile/random.c
+++ b/libguile/random.c
@@ -25,7 +25,11 @@
#include "libguile/_scm.h"
+#if HAVE_LIBGMP
#include <gmp.h>
+#else
+#include "mini-gmp.h"
+#endif
#include <stdio.h>
#include <math.h>
#include <string.h>
diff --git a/libguile/socket.c b/libguile/socket.c
index d085d33..5ec20a2 100644
--- a/libguile/socket.c
+++ b/libguile/socket.c
@@ -25,7 +25,11 @@
#endif
#include <errno.h>
+#if HAVE_LIBGMP
#include <gmp.h>
+#else
+#include "mini-gmp.h"
+#endif
#include "libguile/_scm.h"
#include "libguile/arrays.h"
Regards,
/Niels
--
Niels Möller. PGP-encrypted email is preferred. Keyid C0B98E26.
Internet email is subject to wholesale government surveillance.
