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guile/libguile/foreign.c
Ludovic Courtès 012062a0d6 Fix small integer return value packing on big endian machines. 
* libguile/foreign.c (pack): Add `return_value_p' parameter.  Update
  callers.
  When RETURN_VALUE_P is true, assume LOC points to an `ffi_arg', and
  cast its results to the relevant type.  This fixes packing of integer
  return values smaller than `int' on SPARC64 and PowerPC64.  Reported
  by Nelson H. F. Beebe <beebe@math.utah.edu>.
2011-05-08 17:24:24 +02:00

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/* Copyright (C) 2010, 2011 Free Software Foundation, Inc.
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public License
* as published by the Free Software Foundation; either version 3 of
* the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
* 02110-1301 USA
*/
#if HAVE_CONFIG_H
# include <config.h>
#endif
#include <ffi.h>
#include <alloca.h>
#include <alignof.h>
#include <string.h>
#include <assert.h>
#include "libguile/_scm.h"
#include "libguile/bytevectors.h"
#include "libguile/instructions.h"
#include "libguile/threads.h"
#include "libguile/foreign.h"
SCM_SYMBOL (sym_void, "void");
SCM_SYMBOL (sym_float, "float");
SCM_SYMBOL (sym_double, "double");
SCM_SYMBOL (sym_uint8, "uint8");
SCM_SYMBOL (sym_int8, "int8");
SCM_SYMBOL (sym_uint16, "uint16");
SCM_SYMBOL (sym_int16, "int16");
SCM_SYMBOL (sym_uint32, "uint32");
SCM_SYMBOL (sym_int32, "int32");
SCM_SYMBOL (sym_uint64, "uint64");
SCM_SYMBOL (sym_int64, "int64");
SCM_SYMBOL (sym_short, "short");
SCM_SYMBOL (sym_int, "int");
SCM_SYMBOL (sym_long, "long");
SCM_SYMBOL (sym_unsigned_short, "unsigned-short");
SCM_SYMBOL (sym_unsigned_int, "unsigned-int");
SCM_SYMBOL (sym_unsigned_long, "unsigned-long");
SCM_SYMBOL (sym_size_t, "size_t");
/* that's for pointers, you know. */
SCM_SYMBOL (sym_asterisk, "*");
SCM_SYMBOL (sym_null, "%null-pointer");
SCM_SYMBOL (sym_null_pointer_error, "null-pointer-error");
/* The cell representing the null pointer. */
static SCM null_pointer;
#if SIZEOF_VOID_P == 4
# define scm_to_uintptr scm_to_uint32
# define scm_from_uintptr scm_from_uint32
#elif SIZEOF_VOID_P == 8
# define scm_to_uintptr scm_to_uint64
# define scm_from_uintptr scm_from_uint64
#else
# error unsupported pointer size
#endif
/* Raise a null pointer dereference error. */
static void
null_pointer_error (const char *func_name)
{
scm_error (sym_null_pointer_error, func_name,
"null pointer dereference", SCM_EOL, SCM_EOL);
}
static SCM cif_to_procedure (SCM cif, SCM func_ptr);
static SCM pointer_weak_refs = SCM_BOOL_F;
static scm_i_pthread_mutex_t weak_refs_lock = SCM_I_PTHREAD_MUTEX_INITIALIZER;
static void
register_weak_reference (SCM from, SCM to)
{
scm_i_pthread_mutex_lock (&weak_refs_lock);
scm_hashq_set_x (pointer_weak_refs, from, to);
scm_i_pthread_mutex_unlock (&weak_refs_lock);
}
static void
pointer_finalizer_trampoline (GC_PTR ptr, GC_PTR data)
{
scm_t_pointer_finalizer finalizer = data;
finalizer (SCM_POINTER_VALUE (PTR2SCM (ptr)));
}
SCM_DEFINE (scm_pointer_p, "pointer?", 1, 0, 0,
(SCM obj),
"Return @code{#t} if @var{obj} is a pointer object, "
"@code{#f} otherwise.\n")
#define FUNC_NAME s_scm_pointer_p
{
return scm_from_bool (SCM_POINTER_P (obj));
}
#undef FUNC_NAME
SCM_DEFINE (scm_make_pointer, "make-pointer", 1, 1, 0,
(SCM address, SCM finalizer),
"Return a foreign pointer object pointing to @var{address}. "
"If @var{finalizer} is passed, it should be a pointer to a "
"one-argument C function that will be called when the pointer "
"object becomes unreachable.")
#define FUNC_NAME s_scm_make_pointer
{
void *c_finalizer;
scm_t_uintptr c_address;
c_address = scm_to_uintptr (address);
if (SCM_UNBNDP (finalizer))
c_finalizer = NULL;
else
{
SCM_VALIDATE_POINTER (2, finalizer);
c_finalizer = SCM_POINTER_VALUE (finalizer);
}
return scm_from_pointer ((void *) c_address, c_finalizer);
}
#undef FUNC_NAME
SCM
scm_from_pointer (void *ptr, scm_t_pointer_finalizer finalizer)
{
SCM ret;
if (ptr == NULL && finalizer == NULL)
ret = null_pointer;
else
{
ret = scm_cell (scm_tc7_pointer, (scm_t_bits) ptr);
if (finalizer)
{
/* Register a finalizer for the newly created instance. */
GC_finalization_proc prev_finalizer;
GC_PTR prev_finalizer_data;
GC_REGISTER_FINALIZER_NO_ORDER (SCM2PTR (ret),
pointer_finalizer_trampoline,
finalizer,
&prev_finalizer,
&prev_finalizer_data);
}
}
return ret;
}
SCM_DEFINE (scm_pointer_address, "pointer-address", 1, 0, 0,
(SCM pointer),
"Return the numerical value of @var{pointer}.")
#define FUNC_NAME s_scm_pointer_address
{
SCM_VALIDATE_POINTER (1, pointer);
return scm_from_uintptr ((scm_t_uintptr) SCM_POINTER_VALUE (pointer));
}
#undef FUNC_NAME
SCM_DEFINE (scm_pointer_to_scm, "pointer->scm", 1, 0, 0,
(SCM pointer),
"Unsafely cast @var{pointer} to a Scheme object.\n"
"Cross your fingers!")
#define FUNC_NAME s_scm_pointer_to_scm
{
SCM_VALIDATE_POINTER (1, pointer);
return SCM_PACK ((scm_t_bits) SCM_POINTER_VALUE (pointer));
}
#undef FUNC_NAME
SCM_DEFINE (scm_scm_to_pointer, "scm->pointer", 1, 0, 0,
(SCM scm),
"Return a foreign pointer object with the @code{object-address}\n"
"of @var{scm}.")
#define FUNC_NAME s_scm_scm_to_pointer
{
SCM ret;
ret = scm_from_pointer ((void*) SCM_UNPACK (scm), NULL);
if (SCM_NIMP (ret))
register_weak_reference (ret, scm);
return ret;
}
#undef FUNC_NAME
SCM_DEFINE (scm_pointer_to_bytevector, "pointer->bytevector", 2, 2, 0,
(SCM pointer, SCM len, SCM offset, SCM uvec_type),
"Return a bytevector aliasing the @var{len} bytes pointed\n"
"to by @var{pointer}.\n\n"
"The user may specify an alternate default interpretation for\n"
"the memory by passing the @var{uvec_type} argument, to indicate\n"
"that the memory is an array of elements of that type.\n"
"@var{uvec_type} should be something that\n"
"@code{uniform-vector-element-type} would return, like @code{f32}\n"
"or @code{s16}.\n\n"
"When @var{offset} is passed, it specifies the offset in bytes\n"
"relative to @var{pointer} of the memory region aliased by the\n"
"returned bytevector.")
#define FUNC_NAME s_scm_pointer_to_bytevector
{
SCM ret;
scm_t_int8 *ptr;
size_t boffset, blen;
scm_t_array_element_type btype;
SCM_VALIDATE_POINTER (1, pointer);
ptr = SCM_POINTER_VALUE (pointer);
if (SCM_UNLIKELY (ptr == NULL))
null_pointer_error (FUNC_NAME);
if (SCM_UNBNDP (uvec_type))
btype = SCM_ARRAY_ELEMENT_TYPE_VU8;
else
{
int i;
for (i = 0; i <= SCM_ARRAY_ELEMENT_TYPE_LAST; i++)
if (scm_is_eq (uvec_type, scm_i_array_element_types[i]))
break;
switch (i)
{
case SCM_ARRAY_ELEMENT_TYPE_VU8:
case SCM_ARRAY_ELEMENT_TYPE_U8:
case SCM_ARRAY_ELEMENT_TYPE_S8:
case SCM_ARRAY_ELEMENT_TYPE_U16:
case SCM_ARRAY_ELEMENT_TYPE_S16:
case SCM_ARRAY_ELEMENT_TYPE_U32:
case SCM_ARRAY_ELEMENT_TYPE_S32:
case SCM_ARRAY_ELEMENT_TYPE_U64:
case SCM_ARRAY_ELEMENT_TYPE_S64:
case SCM_ARRAY_ELEMENT_TYPE_F32:
case SCM_ARRAY_ELEMENT_TYPE_F64:
case SCM_ARRAY_ELEMENT_TYPE_C32:
case SCM_ARRAY_ELEMENT_TYPE_C64:
btype = i;
break;
default:
scm_wrong_type_arg_msg (FUNC_NAME, SCM_ARG1, uvec_type,
"uniform vector type");
}
}
if (SCM_UNBNDP (offset))
boffset = 0;
else
boffset = scm_to_size_t (offset);
blen = scm_to_size_t (len);
ret = scm_c_take_typed_bytevector (ptr + boffset, blen, btype);
register_weak_reference (ret, pointer);
return ret;
}
#undef FUNC_NAME
SCM_DEFINE (scm_bytevector_to_pointer, "bytevector->pointer", 1, 1, 0,
(SCM bv, SCM offset),
"Return a pointer pointer aliasing the memory pointed to by\n"
"@var{bv} or @var{offset} bytes after @var{bv} when @var{offset}\n"
"is passed.")
#define FUNC_NAME s_scm_bytevector_to_pointer
{
SCM ret;
scm_t_int8 *ptr;
size_t boffset;
SCM_VALIDATE_BYTEVECTOR (1, bv);
ptr = SCM_BYTEVECTOR_CONTENTS (bv);
if (SCM_UNBNDP (offset))
boffset = 0;
else
boffset = scm_to_unsigned_integer (offset, 0,
SCM_BYTEVECTOR_LENGTH (bv) - 1);
ret = scm_from_pointer (ptr + boffset, NULL);
register_weak_reference (ret, bv);
return ret;
}
#undef FUNC_NAME
SCM_DEFINE (scm_set_pointer_finalizer_x, "set-pointer-finalizer!", 2, 0, 0,
(SCM pointer, SCM finalizer),
"Arrange for the C procedure wrapped by @var{finalizer} to be\n"
"called on the pointer wrapped by @var{pointer} when @var{pointer}\n"
"becomes unreachable. Note: the C procedure should not call into\n"
"Scheme. If you need a Scheme finalizer, use guardians.")
#define FUNC_NAME s_scm_set_pointer_finalizer_x
{
void *c_finalizer;
GC_finalization_proc prev_finalizer;
GC_PTR prev_finalizer_data;
SCM_VALIDATE_POINTER (1, pointer);
SCM_VALIDATE_POINTER (2, finalizer);
c_finalizer = SCM_POINTER_VALUE (finalizer);
SCM_SET_CELL_WORD_0 (pointer, SCM_CELL_WORD_0 (pointer) | (1 << 16UL));
GC_REGISTER_FINALIZER_NO_ORDER (SCM2PTR (pointer),
pointer_finalizer_trampoline,
c_finalizer,
&prev_finalizer,
&prev_finalizer_data);
return SCM_UNSPECIFIED;
}
#undef FUNC_NAME
void
scm_i_pointer_print (SCM pointer, SCM port, scm_print_state *pstate)
{
scm_puts ("#<pointer 0x", port);
scm_uintprint (scm_to_uintptr (scm_pointer_address (pointer)), 16, port);
scm_putc ('>', port);
}
/* Non-primitive helpers functions. These procedures could be
implemented in terms of the primitives above but would be inefficient
(heap allocation overhead, Scheme/C round trips, etc.) */
SCM_DEFINE (scm_dereference_pointer, "dereference-pointer", 1, 0, 0,
(SCM pointer),
"Assuming @var{pointer} points to a memory region that\n"
"holds a pointer, return this pointer.")
#define FUNC_NAME s_scm_dereference_pointer
{
SCM_VALIDATE_POINTER (1, pointer);
return scm_from_pointer (* (void **) SCM_POINTER_VALUE (pointer), NULL);
}
#undef FUNC_NAME
SCM_DEFINE (scm_string_to_pointer, "string->pointer", 1, 1, 0,
(SCM string, SCM encoding),
"Return a foreign pointer to a nul-terminated copy of\n"
"@var{string} in the given @var{encoding}, defaulting to\n"
"the current locale encoding. The C string is freed when\n"
"the returned foreign pointer becomes unreachable.\n\n"
"This is the Scheme equivalent of @code{scm_to_stringn}.")
#define FUNC_NAME s_scm_string_to_pointer
{
SCM_VALIDATE_STRING (1, string);
/* XXX: Finalizers slow down libgc; they could be avoided if
`scm_to_string' & co. were able to use libgc-allocated memory. */
if (SCM_UNBNDP (encoding))
return scm_from_pointer (scm_to_locale_string (string), free);
else
{
char *enc;
SCM ret;
SCM_VALIDATE_STRING (2, encoding);
enc = scm_to_locale_string (encoding);
scm_dynwind_begin (0);
scm_dynwind_free (enc);
ret = scm_from_pointer
(scm_to_stringn (string, NULL, enc,
scm_i_get_conversion_strategy (SCM_BOOL_F)),
free);
scm_dynwind_end ();
return ret;
}
}
#undef FUNC_NAME
SCM_DEFINE (scm_pointer_to_string, "pointer->string", 1, 2, 0,
(SCM pointer, SCM length, SCM encoding),
"Return the string representing the C string pointed to by\n"
"@var{pointer}. If @var{length} is omitted or @code{-1}, the\n"
"string is assumed to be nul-terminated. Otherwise\n"
"@var{length} is the number of bytes in memory pointed to by\n"
"@var{pointer}. The C string is assumed to be in the given\n"
"@var{encoding}, defaulting to the current locale encoding.\n\n"
"This is the Scheme equivalent of @code{scm_from_stringn}.")
#define FUNC_NAME s_scm_pointer_to_string
{
size_t len;
SCM_VALIDATE_POINTER (1, pointer);
if (SCM_UNBNDP (length)
|| scm_is_true (scm_eqv_p (length, scm_from_int (-1))))
len = (size_t)-1;
else
len = scm_to_size_t (length);
if (SCM_UNBNDP (encoding))
return scm_from_locale_stringn (SCM_POINTER_VALUE (pointer), len);
else
{
char *enc;
SCM ret;
SCM_VALIDATE_STRING (3, encoding);
enc = scm_to_locale_string (encoding);
scm_dynwind_begin (0);
scm_dynwind_free (enc);
ret = scm_from_stringn (SCM_POINTER_VALUE (pointer), len, enc,
scm_i_get_conversion_strategy (SCM_BOOL_F));
scm_dynwind_end ();
return ret;
}
}
#undef FUNC_NAME
SCM_DEFINE (scm_alignof, "alignof", 1, 0, 0, (SCM type),
"Return the alignment of @var{type}, in bytes.\n\n"
"@var{type} should be a valid C type, like @code{int}.\n"
"Alternately @var{type} may be the symbol @code{*}, in which\n"
"case the alignment of a pointer is returned. @var{type} may\n"
"also be a list of types, in which case the alignment of a\n"
"@code{struct} with ABI-conventional packing is returned.")
#define FUNC_NAME s_scm_alignof
{
if (SCM_I_INUMP (type))
{
switch (SCM_I_INUM (type))
{
case SCM_FOREIGN_TYPE_FLOAT:
return scm_from_size_t (alignof (float));
case SCM_FOREIGN_TYPE_DOUBLE:
return scm_from_size_t (alignof (double));
case SCM_FOREIGN_TYPE_UINT8:
return scm_from_size_t (alignof (scm_t_uint8));
case SCM_FOREIGN_TYPE_INT8:
return scm_from_size_t (alignof (scm_t_int8));
case SCM_FOREIGN_TYPE_UINT16:
return scm_from_size_t (alignof (scm_t_uint16));
case SCM_FOREIGN_TYPE_INT16:
return scm_from_size_t (alignof (scm_t_int16));
case SCM_FOREIGN_TYPE_UINT32:
return scm_from_size_t (alignof (scm_t_uint32));
case SCM_FOREIGN_TYPE_INT32:
return scm_from_size_t (alignof (scm_t_int32));
case SCM_FOREIGN_TYPE_UINT64:
return scm_from_size_t (alignof (scm_t_uint64));
case SCM_FOREIGN_TYPE_INT64:
return scm_from_size_t (alignof (scm_t_int64));
default:
scm_wrong_type_arg (FUNC_NAME, 1, type);
}
}
else if (scm_is_eq (type, sym_asterisk))
/* a pointer */
return scm_from_size_t (alignof (void*));
else if (scm_is_pair (type))
{
/* TYPE is a structure. Section 3-3 of the i386, x86_64, PowerPC,
and SPARC P.S. of the System V ABI all say: "Aggregates
(structures and arrays) and unions assume the alignment of
their most strictly aligned component." */
size_t max;
for (max = 0; scm_is_pair (type); type = SCM_CDR (type))
{
size_t align;
align = scm_to_size_t (scm_alignof (SCM_CAR (type)));
if (align > max)
max = align;
}
return scm_from_size_t (max);
}
else
scm_wrong_type_arg (FUNC_NAME, 1, type);
}
#undef FUNC_NAME
SCM_DEFINE (scm_sizeof, "sizeof", 1, 0, 0, (SCM type),
"Return the size of @var{type}, in bytes.\n\n"
"@var{type} should be a valid C type, like @code{int}.\n"
"Alternately @var{type} may be the symbol @code{*}, in which\n"
"case the size of a pointer is returned. @var{type} may also\n"
"be a list of types, in which case the size of a @code{struct}\n"
"with ABI-conventional packing is returned.")
#define FUNC_NAME s_scm_sizeof
{
if (SCM_I_INUMP (type))
{
switch (SCM_I_INUM (type))
{
case SCM_FOREIGN_TYPE_FLOAT:
return scm_from_size_t (sizeof (float));
case SCM_FOREIGN_TYPE_DOUBLE:
return scm_from_size_t (sizeof (double));
case SCM_FOREIGN_TYPE_UINT8:
return scm_from_size_t (sizeof (scm_t_uint8));
case SCM_FOREIGN_TYPE_INT8:
return scm_from_size_t (sizeof (scm_t_int8));
case SCM_FOREIGN_TYPE_UINT16:
return scm_from_size_t (sizeof (scm_t_uint16));
case SCM_FOREIGN_TYPE_INT16:
return scm_from_size_t (sizeof (scm_t_int16));
case SCM_FOREIGN_TYPE_UINT32:
return scm_from_size_t (sizeof (scm_t_uint32));
case SCM_FOREIGN_TYPE_INT32:
return scm_from_size_t (sizeof (scm_t_int32));
case SCM_FOREIGN_TYPE_UINT64:
return scm_from_size_t (sizeof (scm_t_uint64));
case SCM_FOREIGN_TYPE_INT64:
return scm_from_size_t (sizeof (scm_t_int64));
default:
scm_wrong_type_arg (FUNC_NAME, 1, type);
}
}
else if (scm_is_eq (type, sym_asterisk))
/* a pointer */
return scm_from_size_t (sizeof (void*));
else if (scm_is_pair (type))
{
/* a struct */
size_t off = 0;
while (scm_is_pair (type))
{
off = ROUND_UP (off, scm_to_size_t (scm_alignof (scm_car (type))));
off += scm_to_size_t (scm_sizeof (scm_car (type)));
type = scm_cdr (type);
}
return scm_from_size_t (off);
}
else
scm_wrong_type_arg (FUNC_NAME, 1, type);
}
#undef FUNC_NAME
/* return 1 on success, 0 on failure */
static int
parse_ffi_type (SCM type, int return_p, long *n_structs, long *n_struct_elts)
{
if (SCM_I_INUMP (type))
{
if ((SCM_I_INUM (type) < 0 )
|| (SCM_I_INUM (type) > SCM_FOREIGN_TYPE_LAST))
return 0;
else if (SCM_I_INUM (type) == SCM_FOREIGN_TYPE_VOID && !return_p)
return 0;
else
return 1;
}
else if (scm_is_eq (type, sym_asterisk))
/* a pointer */
return 1;
else
{
long len;
len = scm_ilength (type);
if (len < 1)
return 0;
while (len--)
{
if (!parse_ffi_type (scm_car (type), 0, n_structs, n_struct_elts))
return 0;
(*n_struct_elts)++;
type = scm_cdr (type);
}
(*n_structs)++;
return 1;
}
}
static void
fill_ffi_type (SCM type, ffi_type *ftype, ffi_type ***type_ptrs,
ffi_type **types)
{
if (SCM_I_INUMP (type))
{
switch (SCM_I_INUM (type))
{
case SCM_FOREIGN_TYPE_FLOAT:
*ftype = ffi_type_float;
return;
case SCM_FOREIGN_TYPE_DOUBLE:
*ftype = ffi_type_double;
return;
case SCM_FOREIGN_TYPE_UINT8:
*ftype = ffi_type_uint8;
return;
case SCM_FOREIGN_TYPE_INT8:
*ftype = ffi_type_sint8;
return;
case SCM_FOREIGN_TYPE_UINT16:
*ftype = ffi_type_uint16;
return;
case SCM_FOREIGN_TYPE_INT16:
*ftype = ffi_type_sint16;
return;
case SCM_FOREIGN_TYPE_UINT32:
*ftype = ffi_type_uint32;
return;
case SCM_FOREIGN_TYPE_INT32:
*ftype = ffi_type_sint32;
return;
case SCM_FOREIGN_TYPE_UINT64:
*ftype = ffi_type_uint64;
return;
case SCM_FOREIGN_TYPE_INT64:
*ftype = ffi_type_sint64;
return;
case SCM_FOREIGN_TYPE_VOID:
*ftype = ffi_type_void;
return;
default:
scm_wrong_type_arg_msg ("pointer->procedure", 0, type,
"foreign type");
}
}
else if (scm_is_eq (type, sym_asterisk))
/* a pointer */
{
*ftype = ffi_type_pointer;
return;
}
else
{
long i, len;
len = scm_ilength (type);
ftype->size = 0;
ftype->alignment = 0;
ftype->type = FFI_TYPE_STRUCT;
ftype->elements = *type_ptrs;
*type_ptrs += len + 1;
for (i = 0; i < len; i++)
{
ftype->elements[i] = *types;
*types += 1;
fill_ffi_type (scm_car (type), ftype->elements[i],
type_ptrs, types);
type = scm_cdr (type);
}
ftype->elements[i] = NULL;
}
}
/* Return a "cif" (call interface) for the given RETURN_TYPE and
ARG_TYPES. */
static ffi_cif *
make_cif (SCM return_type, SCM arg_types, const char *caller)
#define FUNC_NAME caller
{
SCM walk;
long i, nargs, n_structs, n_struct_elts;
size_t cif_len;
char *mem;
ffi_cif *cif;
ffi_type **type_ptrs;
ffi_type *types;
nargs = scm_ilength (arg_types);
SCM_ASSERT (nargs >= 0, arg_types, 3, FUNC_NAME);
/* fixme: assert nargs < 1<<32 */
n_structs = n_struct_elts = 0;
/* For want of talloc, we're going to have to do this in two passes: first we
figure out how much memory is needed for all types, then we allocate the
cif and the types all in one block. */
if (!parse_ffi_type (return_type, 1, &n_structs, &n_struct_elts))
scm_wrong_type_arg (FUNC_NAME, 1, return_type);
for (walk = arg_types; scm_is_pair (walk); walk = scm_cdr (walk))
if (!parse_ffi_type (scm_car (walk), 0, &n_structs, &n_struct_elts))
scm_wrong_type_arg (FUNC_NAME, 3, scm_car (walk));
/* the memory: with space for the cif itself */
cif_len = sizeof (ffi_cif);
/* then ffi_type pointers: one for each arg, one for each struct
element, and one for each struct (for null-termination) */
cif_len = (ROUND_UP (cif_len, alignof(void*))
+ (nargs + n_structs + n_struct_elts)*sizeof(void*));
/* then the ffi_type structs themselves, one per arg and struct element, and
one for the return val */
cif_len = (ROUND_UP (cif_len, alignof(ffi_type))
+ (nargs + n_struct_elts + 1)*sizeof(ffi_type));
mem = scm_gc_malloc_pointerless (cif_len, "foreign");
/* ensure all the memory is initialized, even the holes */
memset (mem, 0, cif_len);
cif = (ffi_cif *) mem;
/* reuse cif_len to walk through the mem */
cif_len = ROUND_UP (sizeof (ffi_cif), alignof(void*));
type_ptrs = (ffi_type**)(mem + cif_len);
cif_len = ROUND_UP (cif_len
+ (nargs + n_structs + n_struct_elts)*sizeof(void*),
alignof(ffi_type));
types = (ffi_type*)(mem + cif_len);
/* whew. now knit the pointers together. */
cif->rtype = types++;
fill_ffi_type (return_type, cif->rtype, &type_ptrs, &types);
cif->arg_types = type_ptrs;
type_ptrs += nargs;
for (walk = arg_types, i = 0; scm_is_pair (walk); walk = scm_cdr (walk), i++)
{
cif->arg_types[i] = types++;
fill_ffi_type (scm_car (walk), cif->arg_types[i], &type_ptrs, &types);
}
/* round out the cif, and we're done. */
cif->abi = FFI_DEFAULT_ABI;
cif->nargs = nargs;
cif->bytes = 0;
cif->flags = 0;
if (FFI_OK != ffi_prep_cif (cif, FFI_DEFAULT_ABI, cif->nargs, cif->rtype,
cif->arg_types))
SCM_MISC_ERROR ("ffi_prep_cif failed", SCM_EOL);
return cif;
}
#undef FUNC_NAME
SCM_DEFINE (scm_pointer_to_procedure, "pointer->procedure", 3, 0, 0,
(SCM return_type, SCM func_ptr, SCM arg_types),
"Make a foreign function.\n\n"
"Given the foreign void pointer @var{func_ptr}, its argument and\n"
"return types @var{arg_types} and @var{return_type}, return a\n"
"procedure that will pass arguments to the foreign function\n"
"and return appropriate values.\n\n"
"@var{arg_types} should be a list of foreign types.\n"
"@code{return_type} should be a foreign type.")
#define FUNC_NAME s_scm_pointer_to_procedure
{
ffi_cif *cif;
SCM_VALIDATE_POINTER (2, func_ptr);
cif = make_cif (return_type, arg_types, FUNC_NAME);
return cif_to_procedure (scm_from_pointer (cif, NULL), func_ptr);
}
#undef FUNC_NAME
/* Pre-generate trampolines for less than 10 arguments. */
#ifdef WORDS_BIGENDIAN
#define OBJCODE_HEADER 0, 0, 0, 8, 0, 0, 0, 40
#define META_HEADER 0, 0, 0, 32, 0, 0, 0, 0
#else
#define OBJCODE_HEADER 8, 0, 0, 0, 40, 0, 0, 0
#define META_HEADER 32, 0, 0, 0, 0, 0, 0, 0
#endif
#define CODE(nreq) \
OBJCODE_HEADER, \
/* 0 */ scm_op_assert_nargs_ee, 0, nreq, /* assert number of args */ \
/* 3 */ scm_op_object_ref, 0, /* push the pair with the cif and the function pointer */ \
/* 5 */ scm_op_foreign_call, nreq, /* and call (will return value as well) */ \
/* 7 */ scm_op_nop, \
/* 8 */ META (3, 7, nreq)
#define META(start, end, nreq) \
META_HEADER, \
/* 0 */ scm_op_make_eol, /* bindings */ \
/* 1 */ scm_op_make_eol, /* sources */ \
/* 2 */ scm_op_make_int8, start, scm_op_make_int8, end, /* arity: from ip N to ip N */ \
/* 6 */ scm_op_make_int8, nreq, /* the arity is N required args */ \
/* 8 */ scm_op_list, 0, 3, /* make a list of those 3 vals */ \
/* 11 */ scm_op_list, 0, 1, /* and the arities will be a list of that one list */ \
/* 14 */ scm_op_load_symbol, 0, 0, 4, 'n', 'a', 'm', 'e', /* `name' */ \
/* 22 */ scm_op_object_ref, 1, /* the name from the object table */ \
/* 24 */ scm_op_cons, /* make a pair for the properties */ \
/* 25 */ scm_op_list, 0, 4, /* pack bindings, sources, and arities into list */ \
/* 28 */ scm_op_return, /* and return */ \
/* 29 */ scm_op_nop, scm_op_nop, scm_op_nop \
/* 32 */
static const struct
{
scm_t_uint64 dummy; /* ensure 8-byte alignment; perhaps there's a better way */
const scm_t_uint8 bytes[10 * (sizeof (struct scm_objcode) + 8
+ sizeof (struct scm_objcode) + 32)];
} raw_bytecode = {
0,
{
CODE (0), CODE (1), CODE (2), CODE (3), CODE (4),
CODE (5), CODE (6), CODE (7), CODE (8), CODE (9)
}
};
#undef CODE
#undef META
#undef OBJCODE_HEADER
#undef META_HEADER
/*
(defun generate-objcode-cells (n)
"Generate objcode cells for up to N arguments"
(interactive "p")
(let ((i 0))
(while (< i n)
(insert
(format " { STATIC_OBJCODE_TAG, SCM_PACK (raw_bytecode.bytes + %d) },\n"
(* (+ 4 4 8 4 4 32) i)))
(insert " { SCM_BOOL_F, SCM_PACK (0) },\n")
(setq i (1+ i)))))
*/
#define STATIC_OBJCODE_TAG \
SCM_PACK (SCM_MAKE_OBJCODE_TAG (SCM_OBJCODE_TYPE_STATIC, 0))
static const struct
{
scm_t_uint64 dummy; /* alignment */
scm_t_cell cells[10 * 2]; /* 10 double cells */
} objcode_cells = {
0,
/* C-u 1 0 M-x generate-objcode-cells RET */
{
{ STATIC_OBJCODE_TAG, SCM_PACK (raw_bytecode.bytes + 0) },
{ SCM_BOOL_F, SCM_PACK (0) },
{ STATIC_OBJCODE_TAG, SCM_PACK (raw_bytecode.bytes + 56) },
{ SCM_BOOL_F, SCM_PACK (0) },
{ STATIC_OBJCODE_TAG, SCM_PACK (raw_bytecode.bytes + 112) },
{ SCM_BOOL_F, SCM_PACK (0) },
{ STATIC_OBJCODE_TAG, SCM_PACK (raw_bytecode.bytes + 168) },
{ SCM_BOOL_F, SCM_PACK (0) },
{ STATIC_OBJCODE_TAG, SCM_PACK (raw_bytecode.bytes + 224) },
{ SCM_BOOL_F, SCM_PACK (0) },
{ STATIC_OBJCODE_TAG, SCM_PACK (raw_bytecode.bytes + 280) },
{ SCM_BOOL_F, SCM_PACK (0) },
{ STATIC_OBJCODE_TAG, SCM_PACK (raw_bytecode.bytes + 336) },
{ SCM_BOOL_F, SCM_PACK (0) },
{ STATIC_OBJCODE_TAG, SCM_PACK (raw_bytecode.bytes + 392) },
{ SCM_BOOL_F, SCM_PACK (0) },
{ STATIC_OBJCODE_TAG, SCM_PACK (raw_bytecode.bytes + 448) },
{ SCM_BOOL_F, SCM_PACK (0) },
{ STATIC_OBJCODE_TAG, SCM_PACK (raw_bytecode.bytes + 504) },
{ SCM_BOOL_F, SCM_PACK (0) }
}
};
static const SCM objcode_trampolines[10] = {
SCM_PACK (objcode_cells.cells+0),
SCM_PACK (objcode_cells.cells+2),
SCM_PACK (objcode_cells.cells+4),
SCM_PACK (objcode_cells.cells+6),
SCM_PACK (objcode_cells.cells+8),
SCM_PACK (objcode_cells.cells+10),
SCM_PACK (objcode_cells.cells+12),
SCM_PACK (objcode_cells.cells+14),
SCM_PACK (objcode_cells.cells+16),
SCM_PACK (objcode_cells.cells+18),
};
static SCM
cif_to_procedure (SCM cif, SCM func_ptr)
{
ffi_cif *c_cif;
unsigned int nargs;
SCM objcode, table, ret;
c_cif = (ffi_cif *) SCM_POINTER_VALUE (cif);
nargs = c_cif->nargs;
if (nargs < 10)
objcode = objcode_trampolines[nargs];
else
scm_misc_error ("make-foreign-function", "args >= 10 currently unimplemented",
SCM_EOL);
table = scm_c_make_vector (2, SCM_UNDEFINED);
SCM_SIMPLE_VECTOR_SET (table, 0, scm_cons (cif, func_ptr));
SCM_SIMPLE_VECTOR_SET (table, 1, SCM_BOOL_F); /* name */
ret = scm_make_program (objcode, table, SCM_BOOL_F);
return ret;
}
/* Set *LOC to the foreign representation of X with TYPE. */
static void
unpack (const ffi_type *type, void *loc, SCM x)
#define FUNC_NAME "scm_i_foreign_call"
{
switch (type->type)
{
case FFI_TYPE_FLOAT:
*(float *) loc = scm_to_double (x);
break;
case FFI_TYPE_DOUBLE:
*(double *) loc = scm_to_double (x);
break;
case FFI_TYPE_UINT8:
*(scm_t_uint8 *) loc = scm_to_uint8 (x);
break;
case FFI_TYPE_SINT8:
*(scm_t_int8 *) loc = scm_to_int8 (x);
break;
case FFI_TYPE_UINT16:
*(scm_t_uint16 *) loc = scm_to_uint16 (x);
break;
case FFI_TYPE_SINT16:
*(scm_t_int16 *) loc = scm_to_int16 (x);
break;
case FFI_TYPE_UINT32:
*(scm_t_uint32 *) loc = scm_to_uint32 (x);
break;
case FFI_TYPE_SINT32:
*(scm_t_int32 *) loc = scm_to_int32 (x);
break;
case FFI_TYPE_UINT64:
*(scm_t_uint64 *) loc = scm_to_uint64 (x);
break;
case FFI_TYPE_SINT64:
*(scm_t_int64 *) loc = scm_to_int64 (x);
break;
case FFI_TYPE_STRUCT:
SCM_VALIDATE_POINTER (1, x);
memcpy (loc, SCM_POINTER_VALUE (x), type->size);
break;
case FFI_TYPE_POINTER:
SCM_VALIDATE_POINTER (1, x);
*(void **) loc = SCM_POINTER_VALUE (x);
break;
case FFI_TYPE_VOID:
/* Do nothing. */
break;
default:
abort ();
}
}
#undef FUNC_NAME
/* Return a Scheme representation of the foreign value at LOC of type
TYPE. When RETURN_VALUE_P is true, LOC is assumed to point to a
return value buffer; otherwise LOC is assumed to point to an
argument buffer. */
static SCM
pack (const ffi_type * type, const void *loc, int return_value_p)
{
switch (type->type)
{
case FFI_TYPE_VOID:
return SCM_UNSPECIFIED;
case FFI_TYPE_FLOAT:
return scm_from_double (*(float *) loc);
case FFI_TYPE_DOUBLE:
return scm_from_double (*(double *) loc);
/* For integer return values smaller than `int', libffi stores the
result in an `ffi_arg'-long buffer, of which only the
significant bits must be kept---hence the pair of casts below.
See <http://thread.gmane.org/gmane.comp.lib.ffi.general/406>
for details. */
case FFI_TYPE_UINT8:
if (return_value_p)
return scm_from_uint8 ((scm_t_uint8) *(ffi_arg *) loc);
else
return scm_from_uint8 (* (scm_t_uint8 *) loc);
case FFI_TYPE_SINT8:
if (return_value_p)
return scm_from_int8 ((scm_t_int8) *(ffi_arg *) loc);
else
return scm_from_int8 (* (scm_t_int8 *) loc);
case FFI_TYPE_UINT16:
if (return_value_p)
return scm_from_uint16 ((scm_t_uint16) *(ffi_arg *) loc);
else
return scm_from_uint16 (* (scm_t_uint16 *) loc);
case FFI_TYPE_SINT16:
if (return_value_p)
return scm_from_int16 ((scm_t_int16) *(ffi_arg *) loc);
else
return scm_from_int16 (* (scm_t_int16 *) loc);
case FFI_TYPE_UINT32:
if (return_value_p)
return scm_from_uint32 ((scm_t_uint32) *(ffi_arg *) loc);
else
return scm_from_uint32 (* (scm_t_uint32 *) loc);
case FFI_TYPE_SINT32:
if (return_value_p)
return scm_from_int32 ((scm_t_int32) *(ffi_arg *) loc);
else
return scm_from_int32 (* (scm_t_int32 *) loc);
case FFI_TYPE_UINT64:
return scm_from_uint64 (*(scm_t_uint64 *) loc);
case FFI_TYPE_SINT64:
return scm_from_int64 (*(scm_t_int64 *) loc);
case FFI_TYPE_STRUCT:
{
void *mem = scm_gc_malloc_pointerless (type->size, "foreign");
memcpy (mem, loc, type->size);
return scm_from_pointer (mem, NULL);
}
case FFI_TYPE_POINTER:
return scm_from_pointer (*(void **) loc, NULL);
default:
abort ();
}
}
SCM
scm_i_foreign_call (SCM foreign, const SCM *argv)
{
/* FOREIGN is the pair that cif_to_procedure set as the 0th element of the
objtable. */
ffi_cif *cif;
void (*func) (void);
scm_t_uint8 *data;
void *rvalue;
void **args;
unsigned i;
size_t arg_size;
scm_t_ptrdiff off;
cif = SCM_POINTER_VALUE (SCM_CAR (foreign));
func = SCM_POINTER_VALUE (SCM_CDR (foreign));
/* Argument pointers. */
args = alloca (sizeof (void *) * cif->nargs);
/* Compute the worst-case amount of memory needed to store all the argument
values. Note: as of libffi 3.0.9 `cif->bytes' is undocumented and is zero,
so it can't be used for that purpose. */
for (i = 0, arg_size = 0; i < cif->nargs; i++)
arg_size += cif->arg_types[i]->size + cif->arg_types[i]->alignment - 1;
/* Space for argument values, followed by return value. */
data = alloca (arg_size + cif->rtype->size
+ max (sizeof (void *), cif->rtype->alignment));
/* Unpack ARGV to native values, setting ARGV pointers. */
for (i = 0, off = 0;
i < cif->nargs;
off = (scm_t_uint8 *) args[i] - data + cif->arg_types[i]->size,
i++)
{
/* Suitably align the storage area for argument I. */
args[i] = (void *) ROUND_UP ((scm_t_uintptr) data + off,
cif->arg_types[i]->alignment);
assert ((scm_t_uintptr) args[i] % cif->arg_types[i]->alignment == 0);
unpack (cif->arg_types[i], args[i], argv[i]);
}
/* Prepare space for the return value. On some platforms, such as
`armv5tel-*-linux-gnueabi', the return value has to be at least
word-aligned, even if its type doesn't have any alignment requirement as is
the case with `char'. */
rvalue = (void *) ROUND_UP ((scm_t_uintptr) data + off,
max (sizeof (void *), cif->rtype->alignment));
/* off we go! */
ffi_call (cif, func, rvalue, args);
return pack (cif->rtype, rvalue, 1);
}
/* Function pointers aka. "callbacks" or "closures". */
#ifdef FFI_CLOSURES
/* Trampoline to invoke a libffi closure that wraps a Scheme
procedure. */
static void
invoke_closure (ffi_cif *cif, void *ret, void **args, void *data)
{
size_t i;
SCM proc, *argv, result;
proc = PTR2SCM (data);
argv = alloca (cif->nargs * sizeof (*argv));
/* Pack ARGS to SCM values, setting ARGV pointers. */
for (i = 0; i < cif->nargs; i++)
argv[i] = pack (cif->arg_types[i], args[i], 0);
result = scm_call_n (proc, argv, cif->nargs);
unpack (cif->rtype, ret, result);
}
SCM_DEFINE (scm_procedure_to_pointer, "procedure->pointer", 3, 0, 0,
(SCM return_type, SCM proc, SCM arg_types),
"Return a pointer to a C function of type @var{return-type}\n"
"taking arguments of types @var{arg-types} (a list) and\n"
"behaving as a proxy to procedure @var{proc}. Thus\n"
"@var{proc}'s arity, supported argument types, and return\n"
"type should match @var{return-type} and @var{arg-types}.\n")
#define FUNC_NAME s_scm_procedure_to_pointer
{
SCM pointer;
ffi_cif *cif;
ffi_status err;
void *closure, *executable;
cif = make_cif (return_type, arg_types, FUNC_NAME);
closure = ffi_closure_alloc (sizeof (ffi_closure), &executable);
err = ffi_prep_closure_loc ((ffi_closure *) closure, cif,
invoke_closure, SCM2PTR (proc),
executable);
if (err != FFI_OK)
{
ffi_closure_free (closure);
SCM_MISC_ERROR ("`ffi_prep_closure_loc' failed", SCM_EOL);
}
if (closure == executable)
pointer = scm_from_pointer (executable, ffi_closure_free);
else
{
/* CLOSURE needs to be freed eventually. However, since
`GC_all_interior_pointers' is disabled, we can't just register
a finalizer for CLOSURE. Instead, we create a pointer object
for CLOSURE, with a finalizer, and register it as a weak
reference of POINTER. */
SCM friend;
pointer = scm_from_pointer (executable, NULL);
friend = scm_from_pointer (closure, ffi_closure_free);
register_weak_reference (pointer, friend);
}
return pointer;
}
#undef FUNC_NAME
#endif /* FFI_CLOSURES */
static void
scm_init_foreign (void)
{
#ifndef SCM_MAGIC_SNARFER
#include "libguile/foreign.x"
#endif
scm_define (sym_void, scm_from_uint8 (SCM_FOREIGN_TYPE_VOID));
scm_define (sym_float, scm_from_uint8 (SCM_FOREIGN_TYPE_FLOAT));
scm_define (sym_double, scm_from_uint8 (SCM_FOREIGN_TYPE_DOUBLE));
scm_define (sym_uint8, scm_from_uint8 (SCM_FOREIGN_TYPE_UINT8));
scm_define (sym_int8, scm_from_uint8 (SCM_FOREIGN_TYPE_INT8));
scm_define (sym_uint16, scm_from_uint8 (SCM_FOREIGN_TYPE_UINT16));
scm_define (sym_int16, scm_from_uint8 (SCM_FOREIGN_TYPE_INT16));
scm_define (sym_uint32, scm_from_uint8 (SCM_FOREIGN_TYPE_UINT32));
scm_define (sym_int32, scm_from_uint8 (SCM_FOREIGN_TYPE_INT32));
scm_define (sym_uint64, scm_from_uint8 (SCM_FOREIGN_TYPE_UINT64));
scm_define (sym_int64, scm_from_uint8 (SCM_FOREIGN_TYPE_INT64));
scm_define (sym_short,
#if SIZEOF_SHORT == 8
scm_from_uint8 (SCM_FOREIGN_TYPE_INT64)
#elif SIZEOF_SHORT == 4
scm_from_uint8 (SCM_FOREIGN_TYPE_INT32)
#elif SIZEOF_SHORT == 2
scm_from_uint8 (SCM_FOREIGN_TYPE_INT16)
#else
# error unsupported sizeof (short)
#endif
);
scm_define (sym_unsigned_short,
#if SIZEOF_SHORT == 8
scm_from_uint8 (SCM_FOREIGN_TYPE_UINT64)
#elif SIZEOF_SHORT == 4
scm_from_uint8 (SCM_FOREIGN_TYPE_UINT32)
#elif SIZEOF_SHORT == 2
scm_from_uint8 (SCM_FOREIGN_TYPE_UINT16)
#else
# error unsupported sizeof (short)
#endif
);
scm_define (sym_int,
#if SIZEOF_INT == 8
scm_from_uint8 (SCM_FOREIGN_TYPE_INT64)
#elif SIZEOF_INT == 4
scm_from_uint8 (SCM_FOREIGN_TYPE_INT32)
#else
# error unsupported sizeof (int)
#endif
);
scm_define (sym_unsigned_int,
#if SIZEOF_UNSIGNED_INT == 8
scm_from_uint8 (SCM_FOREIGN_TYPE_UINT64)
#elif SIZEOF_UNSIGNED_INT == 4
scm_from_uint8 (SCM_FOREIGN_TYPE_UINT32)
#else
# error unsupported sizeof (unsigned int)
#endif
);
scm_define (sym_long,
#if SIZEOF_LONG == 8
scm_from_uint8 (SCM_FOREIGN_TYPE_INT64)
#elif SIZEOF_LONG == 4
scm_from_uint8 (SCM_FOREIGN_TYPE_INT32)
#else
# error unsupported sizeof (long)
#endif
);
scm_define (sym_unsigned_long,
#if SIZEOF_UNSIGNED_LONG == 8
scm_from_uint8 (SCM_FOREIGN_TYPE_UINT64)
#elif SIZEOF_UNSIGNED_LONG == 4
scm_from_uint8 (SCM_FOREIGN_TYPE_UINT32)
#else
# error unsupported sizeof (unsigned long)
#endif
);
scm_define (sym_size_t,
#if SIZEOF_SIZE_T == 8
scm_from_uint8 (SCM_FOREIGN_TYPE_UINT64)
#elif SIZEOF_SIZE_T == 4
scm_from_uint8 (SCM_FOREIGN_TYPE_UINT32)
#else
# error unsupported sizeof (size_t)
#endif
);
null_pointer = scm_cell (scm_tc7_pointer, 0);
scm_define (sym_null, null_pointer);
}
void
scm_register_foreign (void)
{
scm_c_register_extension ("libguile-" SCM_EFFECTIVE_VERSION,
"scm_init_foreign",
(scm_t_extension_init_func)scm_init_foreign,
NULL);
pointer_weak_refs = scm_make_weak_key_hash_table (SCM_UNDEFINED);
}
/*
Local Variables:
c-file-style: "gnu"
End:
*/
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