-/* Copyright (C) 1995,1996,1998,2000,2001 Free Software Foundation, Inc.
+/* Copyright (C) 1995,1996,1998,2000,2001,2004, 2006, 2008 Free Software Foundation, Inc.
*
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License as published by
- * the Free Software Foundation; either version 2, or (at your option)
- * any later version.
- *
- * This program 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 General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License
- * along with this software; see the file COPYING. If not, write to
- * the Free Software Foundation, Inc., 59 Temple Place, Suite 330,
- * Boston, MA 02111-1307 USA
- *
- * As a special exception, the Free Software Foundation gives permission
- * for additional uses of the text contained in its release of GUILE.
- *
- * The exception is that, if you link the GUILE library with other files
- * to produce an executable, this does not by itself cause the
- * resulting executable to be covered by the GNU General Public License.
- * Your use of that executable is in no way restricted on account of
- * linking the GUILE library code into it.
+ * 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 exception does not however invalidate any other reasons why
- * the executable file might be covered by the GNU General Public License.
+ * 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.
*
- * This exception applies only to the code released by the
- * Free Software Foundation under the name GUILE. If you copy
- * code from other Free Software Foundation releases into a copy of
- * GUILE, as the General Public License permits, the exception does
- * not apply to the code that you add in this way. To avoid misleading
- * anyone as to the status of such modified files, you must delete
- * this exception notice from them.
- *
- * If you write modifications of your own for GUILE, it is your choice
- * whether to permit this exception to apply to your modifications.
- * If you do not wish that, delete this exception notice. */
+ * 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
+ */
\f
+#ifdef HAVE_CONFIG_H
+# include <config.h>
+#endif
+
+#include "libguile/_scm.h"
#include <string.h>
+#include <stdio.h>
-#include "libguile/_scm.h"
+#include "libguile/async.h"
+#include "libguile/debug.h"
#include "libguile/root.h"
#include "libguile/stackchk.h"
#include "libguile/smob.h"
#include "libguile/ports.h"
#include "libguile/dynwind.h"
#include "libguile/values.h"
-
-#ifdef DEBUG_EXTENSIONS
-#include "libguile/debug.h"
-#endif
+#include "libguile/eval.h"
+#include "libguile/vm.h"
#include "libguile/validate.h"
#include "libguile/continuations.h"
{
scm_t_contregs *continuation = SCM_CONTREGS (obj);
+ scm_gc_mark (continuation->root);
scm_gc_mark (continuation->throw_value);
+ scm_gc_mark (continuation->vm_conts);
scm_mark_locations (continuation->stack, continuation->num_stack_items);
#ifdef __ia64__
if (continuation->backing_store)
continuation_free (SCM obj)
{
scm_t_contregs *continuation = SCM_CONTREGS (obj);
- /* stack array size is 1 if num_stack_items is 0 (rootcont). */
+ /* stack array size is 1 if num_stack_items is 0. */
size_t extra_items = (continuation->num_stack_items > 0)
? (continuation->num_stack_items - 1)
: 0;
scm_puts ("#<continuation ", port);
scm_intprint (continuation->num_stack_items, 10, port);
scm_puts (" @ ", port);
- scm_intprint (SCM_CELL_WORD_1 (obj), 16, port);
+ scm_uintprint (SCM_CELL_WORD_1 (obj), 16, port);
scm_putc ('>', port);
return 1;
}
-#ifdef __ia64__
-/* Extern declaration of getcontext()/setcontext() in order to redefine
- getcontext() since on ia64-linux the second return value indicates whether
- it returned from getcontext() itself or by running setcontext(). */
-struct rv
-{
- long retval;
- long first_return;
-};
-extern struct rv getcontext (ucontext_t *);
-extern int setcontext (ucontext_t *);
-#endif /* __ia64__ */
-
/* this may return more than once: the first time with the escape
procedure, then subsequently with the value to be passed to the
continuation. */
SCM
scm_make_continuation (int *first)
{
- volatile SCM cont;
+ scm_i_thread *thread = SCM_I_CURRENT_THREAD;
+ SCM cont;
scm_t_contregs *continuation;
- scm_t_contregs *rootcont = SCM_CONTREGS (scm_rootcont);
long stack_size;
SCM_STACKITEM * src;
-#ifdef __ia64__
- struct rv rv;
-#endif /* __ia64__ */
- SCM_ENTER_A_SECTION;
SCM_FLUSH_REGISTER_WINDOWS;
- stack_size = scm_stack_size (rootcont->base);
+ stack_size = scm_stack_size (thread->continuation_base);
continuation = scm_gc_malloc (sizeof (scm_t_contregs)
+ (stack_size - 1) * sizeof (SCM_STACKITEM),
"continuation");
continuation->num_stack_items = stack_size;
- continuation->dynenv = scm_dynwinds;
+ continuation->dynenv = scm_i_dynwinds ();
continuation->throw_value = SCM_EOL;
- continuation->base = src = rootcont->base;
- continuation->seq = rootcont->seq;
-#ifdef DEBUG_EXTENSIONS
- continuation->dframe = scm_last_debug_frame;
-#endif
- SCM_NEWSMOB (cont, scm_tc16_continuation, continuation);
- SCM_EXIT_A_SECTION;
-
-#ifndef SCM_STACK_GROWS_UP
+ continuation->root = thread->continuation_root;
+ continuation->dframe = scm_i_last_debug_frame ();
+ src = thread->continuation_base;
+#if ! SCM_STACK_GROWS_UP
src -= stack_size;
#endif
+ continuation->offset = continuation->stack - src;
memcpy (continuation->stack, src, sizeof (SCM_STACKITEM) * stack_size);
+ continuation->vm_conts = scm_vm_capture_continuations ();
-#ifdef __ia64__
- rv = getcontext (&continuation->ctx);
- if (rv.first_return)
+ SCM_NEWSMOB (cont, scm_tc16_continuation, continuation);
+
+ *first = !setjmp (continuation->jmpbuf);
+ if (*first)
{
- continuation->backing_store_size =
- continuation->ctx.uc_mcontext.sc_ar_bsp -
- (unsigned long) __libc_ia64_register_backing_store_base;
+#ifdef __ia64__
+ continuation->backing_store_size =
+ (char *) scm_ia64_ar_bsp(&continuation->jmpbuf.ctx)
+ -
+ (char *) thread->register_backing_store_base;
continuation->backing_store = NULL;
continuation->backing_store =
scm_gc_malloc (continuation->backing_store_size,
"continuation backing store");
memcpy (continuation->backing_store,
- (void *) __libc_ia64_register_backing_store_base,
+ (void *) thread->register_backing_store_base,
continuation->backing_store_size);
- *first = 1;
+#endif /* __ia64__ */
return cont;
}
else
{
SCM ret = continuation->throw_value;
- *first = 0;
continuation->throw_value = SCM_BOOL_F;
return ret;
}
-#else /* !__ia64__ */
- if (setjmp (continuation->jmpbuf))
- {
- SCM ret = continuation->throw_value;
- *first = 0;
- continuation->throw_value = SCM_BOOL_F;
- return ret;
- }
- else
- {
- *first = 1;
- return cont;
- }
-#endif /* !__ia64__ */
}
#undef FUNC_NAME
+
+/* Invoking a continuation proceeds as follows:
+ *
+ * - the stack is made large enough for the called continuation
+ * - the old windchain is unwound down to the branching point
+ * - the continuation stack is copied into place
+ * - the windchain is rewound up to the continuation's context
+ * - the continuation is invoked via longjmp (or setcontext)
+ *
+ * This order is important so that unwind and rewind handlers are run
+ * with their correct stack.
+ */
+
static void scm_dynthrow (SCM, SCM);
/* Grow the stack by a fixed amount to provide space to copy in the
* within this function is safe, since only stack frames below this function's
* own frame are overwritten. Thus, memcpy can be used for best performance.
*/
+
+typedef struct {
+ scm_t_contregs *continuation;
+ SCM_STACKITEM *dst;
+} copy_stack_data;
+
static void
-copy_stack_and_call (scm_t_contregs *continuation, SCM val,
+copy_stack (void *data)
+{
+ copy_stack_data *d = (copy_stack_data *)data;
+ memcpy (d->dst, d->continuation->stack,
+ sizeof (SCM_STACKITEM) * d->continuation->num_stack_items);
+ scm_vm_reinstate_continuations (d->continuation->vm_conts);
+#ifdef __ia64__
+ SCM_I_CURRENT_THREAD->pending_rbs_continuation = d->continuation;
+#endif
+}
+
+static void
+copy_stack_and_call (scm_t_contregs *continuation, SCM val,
SCM_STACKITEM * dst)
{
- memcpy (dst, continuation->stack,
- sizeof (SCM_STACKITEM) * continuation->num_stack_items);
+ long delta;
+ copy_stack_data data;
-#ifdef DEBUG_EXTENSIONS
- scm_last_debug_frame = continuation->dframe;
-#endif
+ delta = scm_ilength (scm_i_dynwinds ()) - scm_ilength (continuation->dynenv);
+ data.continuation = continuation;
+ data.dst = dst;
+ scm_i_dowinds (continuation->dynenv, delta, copy_stack, &data);
+
+ scm_i_set_last_debug_frame (continuation->dframe);
continuation->throw_value = val;
-#ifdef __ia64__
- memcpy ((void *) __libc_ia64_register_backing_store_base,
- continuation->backing_store,
- continuation->backing_store_size);
- setcontext (&continuation->ctx);
-#else
longjmp (continuation->jmpbuf, 1);
-#endif
}
+#ifdef __ia64__
+void
+scm_ia64_longjmp (jmp_buf *JB, int VAL)
+{
+ scm_i_thread *t = SCM_I_CURRENT_THREAD;
+
+ if (t->pending_rbs_continuation)
+ {
+ memcpy (t->register_backing_store_base,
+ t->pending_rbs_continuation->backing_store,
+ t->pending_rbs_continuation->backing_store_size);
+ t->pending_rbs_continuation = NULL;
+ }
+ setcontext (&JB->ctx);
+}
+#endif
/* Call grow_stack until the stack space is large enough, then, as the current
* stack frame might get overwritten, let copy_stack_and_call perform the
static void
scm_dynthrow (SCM cont, SCM val)
{
+ scm_i_thread *thread = SCM_I_CURRENT_THREAD;
scm_t_contregs *continuation = SCM_CONTREGS (cont);
- SCM_STACKITEM * dst = SCM_BASE (scm_rootcont);
+ SCM_STACKITEM *dst = thread->continuation_base;
SCM_STACKITEM stack_top_element;
-#ifdef SCM_STACK_GROWS_UP
- if (SCM_PTR_GE (dst + continuation->num_stack_items, &stack_top_element))
+ if (scm_i_critical_section_level)
+ {
+ fprintf (stderr, "continuation invoked from within critical section.\n");
+ abort ();
+ }
+
+#if SCM_STACK_GROWS_UP
+ if (dst + continuation->num_stack_items >= &stack_top_element)
grow_stack (cont, val);
#else
dst -= continuation->num_stack_items;
- if (SCM_PTR_LE (dst, &stack_top_element))
+ if (dst <= &stack_top_element)
grow_stack (cont, val);
#endif /* def SCM_STACK_GROWS_UP */
continuation_apply (SCM cont, SCM args)
#define FUNC_NAME "continuation_apply"
{
+ scm_i_thread *thread = SCM_I_CURRENT_THREAD;
scm_t_contregs *continuation = SCM_CONTREGS (cont);
- scm_t_contregs *rootcont = SCM_CONTREGS (scm_rootcont);
- if (continuation->seq != rootcont->seq
- /* this base comparison isn't needed */
- || continuation->base != rootcont->base)
+ if (continuation->root != thread->continuation_root)
{
- SCM_MISC_ERROR ("continuation from wrong top level: ~S",
- scm_list_1 (cont));
+ SCM_MISC_ERROR
+ ("invoking continuation would cross continuation barrier: ~A",
+ scm_list_1 (cont));
}
- scm_dowinds (continuation->dynenv,
- scm_ilength (scm_dynwinds)
- - scm_ilength (continuation->dynenv));
-
scm_dynthrow (cont, scm_values (args));
return SCM_UNSPECIFIED; /* not reached */
}
#undef FUNC_NAME
+SCM
+scm_i_with_continuation_barrier (scm_t_catch_body body,
+ void *body_data,
+ scm_t_catch_handler handler,
+ void *handler_data,
+ scm_t_catch_handler pre_unwind_handler,
+ void *pre_unwind_handler_data)
+{
+ SCM_STACKITEM stack_item;
+ scm_i_thread *thread = SCM_I_CURRENT_THREAD;
+ SCM old_controot;
+ SCM_STACKITEM *old_contbase;
+ scm_t_debug_frame *old_lastframe;
+ SCM result;
+
+ /* Establish a fresh continuation root.
+ */
+ old_controot = thread->continuation_root;
+ old_contbase = thread->continuation_base;
+ old_lastframe = thread->last_debug_frame;
+ thread->continuation_root = scm_cons (thread->handle, old_controot);
+ thread->continuation_base = &stack_item;
+ thread->last_debug_frame = NULL;
+
+ /* Call FUNC inside a catch all. This is now guaranteed to return
+ directly and exactly once.
+ */
+ result = scm_c_catch (SCM_BOOL_T,
+ body, body_data,
+ handler, handler_data,
+ pre_unwind_handler, pre_unwind_handler_data);
+
+ /* Return to old continuation root.
+ */
+ thread->last_debug_frame = old_lastframe;
+ thread->continuation_base = old_contbase;
+ thread->continuation_root = old_controot;
+
+ return result;
+}
+
+struct c_data {
+ void *(*func) (void *);
+ void *data;
+ void *result;
+};
+
+static SCM
+c_body (void *d)
+{
+ struct c_data *data = (struct c_data *)d;
+ data->result = data->func (data->data);
+ return SCM_UNSPECIFIED;
+}
+
+static SCM
+c_handler (void *d, SCM tag, SCM args)
+{
+ struct c_data *data = (struct c_data *)d;
+ data->result = NULL;
+ return SCM_UNSPECIFIED;
+}
+
+void *
+scm_c_with_continuation_barrier (void *(*func) (void *), void *data)
+{
+ struct c_data c_data;
+ c_data.func = func;
+ c_data.data = data;
+ scm_i_with_continuation_barrier (c_body, &c_data,
+ c_handler, &c_data,
+ scm_handle_by_message_noexit, NULL);
+ return c_data.result;
+}
+
+struct scm_data {
+ SCM proc;
+};
+
+static SCM
+scm_body (void *d)
+{
+ struct scm_data *data = (struct scm_data *)d;
+ return scm_call_0 (data->proc);
+}
+
+static SCM
+scm_handler (void *d, SCM tag, SCM args)
+{
+ return SCM_BOOL_F;
+}
+
+SCM_DEFINE (scm_with_continuation_barrier, "with-continuation-barrier", 1,0,0,
+ (SCM proc),
+"Call @var{proc} and return its result. Do not allow the invocation of\n"
+"continuations that would leave or enter the dynamic extent of the call\n"
+"to @code{with-continuation-barrier}. Such an attempt causes an error\n"
+"to be signaled.\n"
+"\n"
+"Throws (such as errors) that are not caught from within @var{proc} are\n"
+"caught by @code{with-continuation-barrier}. In that case, a short\n"
+"message is printed to the current error port and @code{#f} is returned.\n"
+"\n"
+"Thus, @code{with-continuation-barrier} returns exactly once.\n")
+#define FUNC_NAME s_scm_with_continuation_barrier
+{
+ struct scm_data scm_data;
+ scm_data.proc = proc;
+ return scm_i_with_continuation_barrier (scm_body, &scm_data,
+ scm_handler, &scm_data,
+ scm_handle_by_message_noexit, NULL);
+}
+#undef FUNC_NAME
void
scm_init_continuations ()
scm_set_smob_free (scm_tc16_continuation, continuation_free);
scm_set_smob_print (scm_tc16_continuation, continuation_print);
scm_set_smob_apply (scm_tc16_continuation, continuation_apply, 0, 0, 1);
-#ifndef SCM_MAGIC_SNARFER
#include "libguile/continuations.x"
-#endif
}
/*
HCoop / bpt / guile.git / blobdiff