#ifdef HAVE_CONFIG_H
# include <config.h>
#endif
#include "libguile/_scm.h"
#include <string.h>
#include <stdio.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/eval.h"
#include "libguile/vm.h"
#include "libguile/instructions.h"
#include "libguile/validate.h"
#include "libguile/continuations.h"
static scm_t_bits tc16_continuation;
#define SCM_CONTREGSP(x) SCM_TYP16_PREDICATE (tc16_continuation, x)
#define SCM_CONTREGS(x) ((scm_t_contregs *) SCM_SMOB_DATA_1 (x))
#define SCM_CONTINUATION_LENGTH(x) (SCM_CONTREGS (x)->num_stack_items)
#define SCM_SET_CONTINUATION_LENGTH(x, n)\
(SCM_CONTREGS (x)->num_stack_items = (n))
#define SCM_JMPBUF(x) ((SCM_CONTREGS (x))->jmpbuf)
#define SCM_DYNENV(x) ((SCM_CONTREGS (x))->dynenv)
#define SCM_CONTINUATION_ROOT(x) ((SCM_CONTREGS (x))->root)
#define SCM_DFRAME(x) ((SCM_CONTREGS (x))->dframe)
#ifdef WORDS_BIGENDIAN
#define OBJCODE_HEADER(main,meta) 0, 0, 0, main, 0, 0, 0, meta+8
#define META_HEADER(meta) 0, 0, 0, meta, 0, 0, 0, 0
#else
#define OBJCODE_HEADER(main,meta) main, 0, 0, 0, meta+8, 0, 0, 0
#define META_HEADER(meta) meta, 0, 0, 0, 0, 0, 0, 0
#endif
#define OBJCODE_TAG SCM_MAKE_OBJCODE_TAG (SCM_OBJCODE_TYPE_STATIC, 0)
#if defined (SCM_ALIGNED) && 0
#define SCM_DECLARE_STATIC_ALIGNED_ARRAY(type, sym) \
static const type sym[]
#define SCM_STATIC_ALIGNED_ARRAY(alignment, type, sym) \
static SCM_ALIGNED (alignment) const type sym[]
#define SCM_STATIC_OBJCODE(sym) \
SCM_DECLARE_STATIC_ALIGNED_ARRAY (scm_t_uint8, sym##__bytecode); \
SCM_STATIC_ALIGNED_ARRAY (8, scm_t_cell, sym##__cells) = { \
{ SCM_PACK (OBJCODE_TAG), SCM_PACK (sym##__bytecode) }, \
{ SCM_BOOL_F, SCM_PACK (0) } \
}; \
static const SCM sym = SCM_PACK (sym##__cells); \
SCM_STATIC_ALIGNED_ARRAY (8, scm_t_uint8, sym##__bytecode)
#else
#define SCM_STATIC_OBJCODE(sym) \
static SCM sym; \
static scm_t_uint8 *sym##_bytecode; \
SCM_SNARF_INIT(sym##_bytecode = scm_gc_malloc_pointerless (sizeof(sym##_bytecode__unaligned), "partial continuation stub"); \
memcpy (sym##_bytecode, sym##_bytecode__unaligned, sizeof(sym##_bytecode__unaligned));) \
SCM_SNARF_INIT(sym = scm_double_cell (OBJCODE_TAG, \
(scm_t_bits)sym##_bytecode, \
SCM_UNPACK (SCM_BOOL_F), \
0);) \
static const scm_t_uint8 sym##_bytecode__unaligned[]
#endif
SCM_STATIC_OBJCODE (cont_objcode) = {
OBJCODE_HEADER (8, 19),
scm_op_object_ref, 0,
scm_op_continuation_call,
scm_op_nop,
scm_op_nop, scm_op_nop, scm_op_nop, scm_op_nop,
META_HEADER (19),
scm_op_make_eol,
scm_op_make_eol,
scm_op_make_int8, 0, scm_op_make_int8, 3,
scm_op_make_int8_0,
scm_op_make_int8_0,
scm_op_make_true,
scm_op_list, 0, 5,
scm_op_list, 0, 1,
scm_op_list, 0, 3,
scm_op_return
};
SCM_STATIC_OBJCODE (call_cc_objcode) = {
OBJCODE_HEADER (8, 17),
scm_op_assert_nargs_ee, 0, 1,
scm_op_local_ref, 0,
scm_op_tail_call_cc,
scm_op_nop, scm_op_nop,
META_HEADER (17),
scm_op_make_eol,
scm_op_make_eol,
scm_op_make_int8, 3, scm_op_make_int8, 6,
scm_op_make_int8_1,
scm_op_list, 0, 3,
scm_op_list, 0, 1,
scm_op_list, 0, 3,
scm_op_return
};
static SCM
make_continuation_trampoline (SCM contregs)
{
SCM ret = scm_make_program (cont_objcode,
scm_c_make_vector (1, contregs),
SCM_BOOL_F);
SCM_SET_CELL_WORD_0 (ret,
SCM_CELL_WORD_0 (ret) | SCM_F_PROGRAM_IS_CONTINUATION);
return ret;
}
static int
continuation_print (SCM obj, SCM port, scm_print_state *state SCM_UNUSED)
{
scm_t_contregs *continuation = SCM_CONTREGS (obj);
scm_puts ("#<continuation ", port);
scm_intprint (continuation->num_stack_items, 10, port);
scm_puts (" @ ", port);
scm_uintprint (SCM_SMOB_DATA_1 (obj), 16, port);
scm_putc ('>', port);
return 1;
}
#define FUNC_NAME "scm_i_make_continuation"
SCM
scm_i_make_continuation (int *first, SCM vm, SCM vm_cont)
{
scm_i_thread *thread = SCM_I_CURRENT_THREAD;
SCM cont;
scm_t_contregs *continuation;
long stack_size;
SCM_STACKITEM * src;
SCM_FLUSH_REGISTER_WINDOWS;
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_i_dynwinds ();
continuation->root = thread->continuation_root;
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 = vm;
continuation->vm_cont = vm_cont;
SCM_NEWSMOB (cont, tc16_continuation, continuation);
*first = !SCM_I_SETJMP (continuation->jmpbuf);
if (*first)
{
#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 *) thread->register_backing_store_base,
continuation->backing_store_size);
#endif
return make_continuation_trampoline (cont);
}
else
return SCM_UNDEFINED;
}
#undef FUNC_NAME
static SCM call_cc;
static void
init_call_cc (void)
{
call_cc = scm_make_program (call_cc_objcode, SCM_BOOL_F, SCM_BOOL_F);
}
SCM
scm_i_call_with_current_continuation (SCM proc)
{
static scm_i_pthread_once_t once = SCM_I_PTHREAD_ONCE_INIT;
scm_i_pthread_once (&once, init_call_cc);
return scm_call_1 (call_cc, proc);
}
SCM
scm_i_continuation_to_frame (SCM continuation)
{
SCM contregs;
scm_t_contregs *cont;
contregs = scm_c_vector_ref (scm_program_objects (continuation), 0);
cont = SCM_CONTREGS (contregs);
if (scm_is_true (cont->vm_cont))
{
struct scm_vm_cont *data = SCM_VM_CONT_DATA (cont->vm_cont);
return scm_c_make_frame (cont->vm_cont,
data->fp + data->reloc,
data->sp + data->reloc,
data->ra,
data->reloc);
}
else
return SCM_BOOL_F;
}
SCM
scm_i_contregs_vm (SCM contregs)
{
return SCM_CONTREGS (contregs)->vm;
}
SCM
scm_i_contregs_vm_cont (SCM contregs)
{
return SCM_CONTREGS (contregs)->vm_cont;
}
static void scm_dynthrow (SCM);
static scm_t_bits scm_i_dummy;
static void
grow_stack (SCM cont)
{
scm_t_bits growth[100];
scm_i_dummy = (scm_t_bits) growth;
scm_dynthrow (cont);
}
typedef struct {
scm_t_contregs *continuation;
SCM_STACKITEM *dst;
} copy_stack_data;
static void
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);
#ifdef __ia64__
SCM_I_CURRENT_THREAD->pending_rbs_continuation = d->continuation;
#endif
}
static void
copy_stack_and_call (scm_t_contregs *continuation,
SCM_STACKITEM * dst)
{
long delta;
copy_stack_data data;
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_LONGJMP (continuation->jmpbuf, 1);
}
#ifdef __ia64__
void
scm_ia64_longjmp (scm_i_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
static void
scm_dynthrow (SCM cont)
{
scm_i_thread *thread = SCM_I_CURRENT_THREAD;
scm_t_contregs *continuation = SCM_CONTREGS (cont);
SCM_STACKITEM *dst = thread->continuation_base;
SCM_STACKITEM stack_top_element;
if (thread->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);
#else
dst -= continuation->num_stack_items;
if (dst <= &stack_top_element)
grow_stack (cont);
#endif
SCM_FLUSH_REGISTER_WINDOWS;
copy_stack_and_call (continuation, dst);
}
void
scm_i_check_continuation (SCM cont)
{
scm_i_thread *thread = SCM_I_CURRENT_THREAD;
scm_t_contregs *continuation = SCM_CONTREGS (cont);
if (!scm_is_eq (continuation->root, thread->continuation_root))
scm_misc_error
("%continuation-call",
"invoking continuation would cross continuation barrier: ~A",
scm_list_1 (cont));
}
void
scm_i_reinstate_continuation (SCM cont)
{
scm_dynthrow (cont);
}
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 result;
old_controot = thread->continuation_root;
old_contbase = thread->continuation_base;
thread->continuation_root = scm_cons (thread->handle, old_controot);
thread->continuation_base = &stack_item;
result = scm_c_catch (SCM_BOOL_T,
body, body_data,
handler, handler_data,
pre_unwind_handler, pre_unwind_handler_data);
thread->continuation_base = old_contbase;
thread->continuation_root = old_controot;
return result;
}
static int
should_print_backtrace (SCM tag, SCM stack)
{
return SCM_BACKTRACE_P
&& scm_is_true (stack)
&& scm_initialized_p
&& !scm_is_eq (tag, scm_from_latin1_symbol ("read-error"))
&& !scm_is_eq (tag, scm_from_latin1_symbol ("syntax-error"));
}
static void
print_exception_and_backtrace (SCM port, SCM tag, SCM args)
{
SCM stack, frame;
stack = scm_make_stack (SCM_BOOL_T, scm_list_1 (scm_from_int (2)));
frame = scm_is_true (stack) ? scm_stack_ref (stack, SCM_INUM0) : SCM_BOOL_F;
if (should_print_backtrace (tag, stack))
{
scm_puts ("Backtrace:\n", port);
scm_display_backtrace_with_highlights (stack, port,
SCM_BOOL_F, SCM_BOOL_F,
SCM_EOL);
scm_newline (port);
}
scm_print_exception (port, frame, tag, args);
}
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;
if (scm_is_eq (tag, scm_from_latin1_symbol ("quit")))
exit (scm_exit_status (args));
data = (struct c_data *)d;
data->result = NULL;
return SCM_UNSPECIFIED;
}
static SCM
pre_unwind_handler (void *error_port, SCM tag, SCM args)
{
if (!scm_is_eq (tag, scm_from_latin1_symbol ("quit")))
print_exception_and_backtrace (PTR2SCM (error_port), tag, args);
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,
pre_unwind_handler,
SCM2PTR (scm_current_error_port ()));
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)
{
scm_handle_by_message_noexit (NULL, tag, 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,
pre_unwind_handler,
SCM2PTR (scm_current_error_port ()));
}
#undef FUNC_NAME
void
scm_init_continuations ()
{
tc16_continuation = scm_make_smob_type ("continuation", 0);
scm_set_smob_print (tc16_continuation, continuation_print);
#include "libguile/continuations.x"
}