-/* Copyright (C) 1996,1997,2000,2001, 2004, 2006, 2007, 2008, 2009 Free Software Foundation, Inc.
+/* Copyright (C) 1996,1997,2000,2001, 2004, 2006, 2007, 2008, 2009, 2010 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
#include <stdio.h>
#include <string.h>
-#include <assert.h>
#include "libguile/_scm.h"
#include "libguile/print.h"
-#include "libguile/smob.h"
#include "libguile/dynwind.h"
#include "libguile/fluids.h"
#include "libguile/alist.h"
#include "libguile/deprecation.h"
#include "libguile/lang.h"
#include "libguile/validate.h"
+#include "libguile/bdw-gc.h"
-#define FLUID_GROW 20
-
-/* A lot of the complexity below stems from the desire to reuse fluid
- slots. Normally, fluids should be pretty global and long-lived
- things, so that reusing their slots should not be overly critical,
- but it is the right thing to do nevertheless. The code therefore
- puts the burdon on allocating and collection fluids and keeps
- accessing fluids lock free. This is achieved by manipulating the
- global state of the fluid machinery mostly in single threaded
- sections.
-
- Reusing a fluid slot means that it must be reset to #f in all
- dynamic states. We do this by maintaining a weak list of all
- dynamic states, which is used after a GC to do the resetting.
-
- Also, the fluid vectors in the dynamic states need to grow from
- time to time when more fluids are created. We do this in a single
- threaded section so that threads do not need to lock when accessing
- a fluid in the normal way.
-*/
-
-static scm_i_pthread_mutex_t fluid_admin_mutex = SCM_I_PTHREAD_MUTEX_INITIALIZER;
+/* Number of additional slots to allocate when ALLOCATED_FLUIDS is full. */
+#define FLUID_GROW 128
-/* Protected by fluid_admin_mutex, but also accessed during GC. See
- next_fluid_num for a discussion of this.
- */
+/* Vector of allocated fluids indexed by fluid numbers. Access is protected by
+ FLUID_ADMIN_MUTEX. */
+static void **allocated_fluids = NULL;
static size_t allocated_fluids_len = 0;
-static size_t allocated_fluids_num = 0;
-static char *allocated_fluids = NULL;
-
-static scm_t_bits tc16_fluid;
-#define IS_FLUID(x) SCM_SMOB_PREDICATE(tc16_fluid, (x))
-#define FLUID_NUM(x) ((size_t)SCM_SMOB_DATA(x))
-#define FLUID_NEXT(x) SCM_SMOB_OBJECT_2(x)
-#define FLUID_NEXT_LOC(x) SCM_SMOB_OBJECT_2_LOC(x)
-#define SET_FLUID_NEXT(x,y) SCM_SET_SMOB_OBJECT_2((x), (y))
+static scm_i_pthread_mutex_t fluid_admin_mutex = SCM_I_PTHREAD_MUTEX_INITIALIZER;
-static scm_t_bits tc16_dynamic_state;
+#define IS_FLUID(x) SCM_I_FLUID_P (x)
+#define FLUID_NUM(x) SCM_I_FLUID_NUM (x)
-#define IS_DYNAMIC_STATE(x) SCM_SMOB_PREDICATE(tc16_dynamic_state, (x))
-#define DYNAMIC_STATE_FLUIDS(x) SCM_SMOB_OBJECT(x)
-#define SET_DYNAMIC_STATE_FLUIDS(x, y) SCM_SET_SMOB_OBJECT((x), (y))
-#define DYNAMIC_STATE_NEXT(x) SCM_SMOB_OBJECT_2(x)
-#define DYNAMIC_STATE_NEXT_LOC(x) SCM_SMOB_OBJECT_2_LOC(x)
-#define SET_DYNAMIC_STATE_NEXT(x, y) SCM_SET_SMOB_OBJECT_2((x), (y))
+#define IS_DYNAMIC_STATE(x) SCM_I_DYNAMIC_STATE_P (x)
+#define DYNAMIC_STATE_FLUIDS(x) SCM_I_DYNAMIC_STATE_FLUIDS (x)
+#define SET_DYNAMIC_STATE_FLUIDS(x, y) SCM_SET_CELL_WORD_1 ((x), (SCM_UNPACK (y)))
\f
-/* Grow STATE so that it can hold up to ALLOCATED_FLUIDS_NUM fluids. */
+/* Grow STATE so that it can hold up to ALLOCATED_FLUIDS_LEN fluids. This may
+ be more than necessary since ALLOCATED_FLUIDS is sparse and the current
+ thread may not access all the fluids anyway. Memory usage could be improved
+ by using a 2-level array as is done in glibc for pthread keys (TODO). */
static void
grow_dynamic_state (SCM state)
{
SCM new_fluids;
SCM old_fluids = DYNAMIC_STATE_FLUIDS (state);
- size_t i, new_len, old_len = SCM_SIMPLE_VECTOR_LENGTH (old_fluids);
+ size_t i, len, old_len = SCM_SIMPLE_VECTOR_LENGTH (old_fluids);
- retry:
- new_len = allocated_fluids_num;
- new_fluids = scm_c_make_vector (new_len, SCM_BOOL_F);
+ /* Assume the assignment below is atomic. */
+ len = allocated_fluids_len;
- scm_i_pthread_mutex_lock (&fluid_admin_mutex);
- if (new_len != allocated_fluids_num)
- {
- /* We lost the race. */
- scm_i_pthread_mutex_unlock (&fluid_admin_mutex);
- goto retry;
- }
-
- assert (allocated_fluids_num > old_len);
+ new_fluids = scm_c_make_vector (len, SCM_BOOL_F);
for (i = 0; i < old_len; i++)
SCM_SIMPLE_VECTOR_SET (new_fluids, i,
SCM_SIMPLE_VECTOR_REF (old_fluids, i));
SET_DYNAMIC_STATE_FLUIDS (state, new_fluids);
-
- scm_i_pthread_mutex_unlock (&fluid_admin_mutex);
}
-static int
-fluid_print (SCM exp, SCM port, scm_print_state *pstate SCM_UNUSED)
+void
+scm_i_fluid_print (SCM exp, SCM port, scm_print_state *pstate SCM_UNUSED)
{
scm_puts ("#<fluid ", port);
scm_intprint ((int) FLUID_NUM (exp), 10, port);
scm_putc ('>', port);
- return 1;
}
-static size_t
-next_fluid_num ()
+void
+scm_i_dynamic_state_print (SCM exp, SCM port, scm_print_state *pstate SCM_UNUSED)
+{
+ scm_puts ("#<dynamic-state ", port);
+ scm_intprint (SCM_UNPACK (exp), 16, port);
+ scm_putc ('>', port);
+}
+
+void
+scm_i_with_fluids_print (SCM exp, SCM port, scm_print_state *pstate SCM_UNUSED)
+{
+ scm_puts ("#<with-fluids ", port);
+ scm_intprint (SCM_UNPACK (exp), 16, port);
+ scm_putc ('>', port);
+}
+
+\f
+/* Return a new fluid. */
+static SCM
+new_fluid ()
{
- size_t n;
+ SCM fluid;
+ size_t trial, n;
+
+ /* Fluids are pointerless cells: the first word is the type tag; the second
+ word is the fluid number. */
+ fluid = PTR2SCM (scm_gc_malloc_pointerless (sizeof (scm_t_cell), "fluid"));
+ SCM_SET_CELL_TYPE (fluid, scm_tc7_fluid);
scm_dynwind_begin (0);
scm_i_dynwind_pthread_mutex_lock (&fluid_admin_mutex);
- if ((allocated_fluids_len > 0) &&
- (allocated_fluids_num == allocated_fluids_len))
- {
- /* All fluid numbers are in use. Run a GC to try to free some
- up.
- */
- scm_gc ();
- }
-
- if (allocated_fluids_num < allocated_fluids_len)
+ for (trial = 0; trial < 2; trial++)
{
+ /* Look for a free fluid number. */
for (n = 0; n < allocated_fluids_len; n++)
- if (allocated_fluids[n] == 0)
+ /* TODO: Use `__sync_bool_compare_and_swap' where available. */
+ if (allocated_fluids[n] == NULL)
break;
+
+ if (trial == 0 && n >= allocated_fluids_len)
+ /* All fluid numbers are in use. Run a GC and retry. Explicitly
+ running the GC is costly and bad-style. We only do this because
+ dynamic state fluid vectors would grow unreasonably if fluid numbers
+ weren't reused. */
+ scm_i_gc ("fluids");
}
- else
+
+ if (n >= allocated_fluids_len)
{
/* Grow the vector of allocated fluids. */
- /* FIXME: Since we use `scm_malloc ()', ALLOCATED_FLUIDS is scanned by
- the GC; therefore, all fluids remain reachable for the entire
- program lifetime. Hopefully this is not a problem in practice. */
- char *new_allocated_fluids =
- scm_gc_malloc (allocated_fluids_len + FLUID_GROW,
- "allocated fluids");
+ void **new_allocated_fluids =
+ scm_gc_malloc_pointerless ((allocated_fluids_len + FLUID_GROW)
+ * sizeof (*allocated_fluids),
+ "allocated fluids");
/* Copy over old values and initialize rest. GC can not run
during these two operations since there is no safe point in
- them.
- */
- memcpy (new_allocated_fluids, allocated_fluids, allocated_fluids_len);
- memset (new_allocated_fluids + allocated_fluids_len, 0, FLUID_GROW);
+ them. */
+ memcpy (new_allocated_fluids, allocated_fluids,
+ allocated_fluids_len * sizeof (*allocated_fluids));
+ memset (new_allocated_fluids + allocated_fluids_len, 0,
+ FLUID_GROW * sizeof (*allocated_fluids));
n = allocated_fluids_len;
/* Update the vector of allocated fluids. Dynamic states will
allocated_fluids = new_allocated_fluids;
allocated_fluids_len += FLUID_GROW;
}
-
- allocated_fluids_num += 1;
- allocated_fluids[n] = 1;
-
+
+ allocated_fluids[n] = SCM2PTR (fluid);
+ SCM_SET_CELL_WORD_1 (fluid, (scm_t_bits) n);
+
+ GC_GENERAL_REGISTER_DISAPPEARING_LINK (&allocated_fluids[n],
+ SCM2PTR (fluid));
+
scm_dynwind_end ();
- return n;
+ return fluid;
}
SCM_DEFINE (scm_make_fluid, "make-fluid", 0, 0, 0,
"with its own dynamic state, you can use fluids for thread local storage.")
#define FUNC_NAME s_scm_make_fluid
{
- SCM fluid;
-
- SCM_NEWSMOB2 (fluid, tc16_fluid,
- (scm_t_bits) next_fluid_num (), SCM_UNPACK (SCM_EOL));
-
- return fluid;
+ return new_fluid ();
}
#undef FUNC_NAME
if (SCM_UNLIKELY (FLUID_NUM (fluid) >= SCM_SIMPLE_VECTOR_LENGTH (fluids)))
{
- /* We should only get there when the current thread's dynamic state
- turns out to be too small compared to the set of currently allocated
- fluids. */
- assert (SCM_SIMPLE_VECTOR_LENGTH (fluids) < allocated_fluids_num);
-
/* Lazily grow the current thread's dynamic state. */
grow_dynamic_state (SCM_I_CURRENT_THREAD->dynamic_state);
if (SCM_UNLIKELY (FLUID_NUM (fluid) >= SCM_SIMPLE_VECTOR_LENGTH (fluids)))
{
- /* We should only get there when the current thread's dynamic state
- turns out to be too small compared to the set of currently allocated
- fluids. */
- assert (SCM_SIMPLE_VECTOR_LENGTH (fluids) < allocated_fluids_num);
-
/* Lazily grow the current thread's dynamic state. */
grow_dynamic_state (SCM_I_CURRENT_THREAD->dynamic_state);
}
#undef FUNC_NAME
-static void
-swap_fluids (SCM data)
+static SCM
+apply_thunk (void *thunk)
{
- SCM fluids = SCM_CAR (data), vals = SCM_CDR (data);
-
- while (!SCM_NULL_OR_NIL_P (fluids))
+ return scm_call_0 (SCM_PACK (thunk));
+}
+
+SCM
+scm_i_make_with_fluids (size_t n, SCM *fluids, SCM *vals)
+{
+ SCM ret;
+
+ /* Ensure that there are no duplicates in the fluids set -- an N^2 operation,
+ but N will usually be small, so perhaps that's OK. */
+ {
+ size_t i, j = n;
+
+ while (j--)
+ for (i = 0; i < j; i++)
+ if (fluids[i] == fluids[j])
+ {
+ vals[i] = vals[j]; /* later bindings win */
+ n--;
+ break;
+ }
+ }
+
+ ret = scm_words (scm_tc7_with_fluids | (n << 8), 1 + n*2);
+ SCM_SET_CELL_WORD_1 (ret, n);
+
+ while (n--)
{
- SCM fl = SCM_CAR (fluids);
- SCM old_val = scm_fluid_ref (fl);
- scm_fluid_set_x (fl, SCM_CAR (vals));
- SCM_SETCAR (vals, old_val);
- fluids = SCM_CDR (fluids);
- vals = SCM_CDR (vals);
+ if (SCM_UNLIKELY (!IS_FLUID (fluids[n])))
+ scm_wrong_type_arg ("with-fluids", 0, fluids[n]);
+ SCM_SET_CELL_OBJECT (ret, 1 + n * 2, fluids[n]);
+ SCM_SET_CELL_OBJECT (ret, 2 + n * 2, vals[n]);
}
+
+ return ret;
}
+
+void
+scm_i_swap_with_fluids (SCM wf, SCM dynstate)
+{
+ SCM fluids;
+ size_t i, max = 0;
-/* Swap the fluid values in reverse order. This is important when the
- same fluid appears multiple times in the fluids list.
-*/
+ fluids = DYNAMIC_STATE_FLUIDS (dynstate);
-static void
-swap_fluids_reverse_aux (SCM fluids, SCM vals)
-{
- if (!SCM_NULL_OR_NIL_P (fluids))
+ /* We could cache the max in the with-fluids, but that would take more mem,
+ and we're touching all the fluids anyway, so this per-swap traversal should
+ be OK. */
+ for (i = 0; i < SCM_WITH_FLUIDS_LEN (wf); i++)
{
- SCM fl, old_val;
-
- swap_fluids_reverse_aux (SCM_CDR (fluids), SCM_CDR (vals));
- fl = SCM_CAR (fluids);
- old_val = scm_fluid_ref (fl);
- scm_fluid_set_x (fl, SCM_CAR (vals));
- SCM_SETCAR (vals, old_val);
+ size_t num = FLUID_NUM (SCM_WITH_FLUIDS_NTH_FLUID (wf, i));
+ max = (max > num) ? max : num;
}
-}
-static void
-swap_fluids_reverse (SCM data)
-{
- swap_fluids_reverse_aux (SCM_CAR (data), SCM_CDR (data));
-}
+ if (SCM_UNLIKELY (max >= SCM_SIMPLE_VECTOR_LENGTH (fluids)))
+ {
+ /* Lazily grow the current thread's dynamic state. */
+ grow_dynamic_state (dynstate);
-static SCM
-apply_thunk (void *thunk)
-{
- return scm_call_0 (SCM_PACK (thunk));
-}
+ fluids = DYNAMIC_STATE_FLUIDS (dynstate);
+ }
+ /* Bind the fluids. Order doesn't matter, as all fluids are distinct. */
+ for (i = 0; i < SCM_WITH_FLUIDS_LEN (wf); i++)
+ {
+ size_t fluid_num;
+ SCM x;
+
+ fluid_num = FLUID_NUM (SCM_WITH_FLUIDS_NTH_FLUID (wf, i));
+ x = SCM_SIMPLE_VECTOR_REF (fluids, fluid_num);
+ SCM_SIMPLE_VECTOR_SET (fluids, fluid_num,
+ SCM_WITH_FLUIDS_NTH_VAL (wf, i));
+ SCM_WITH_FLUIDS_SET_NTH_VAL (wf, i, x);
+ }
+}
+
SCM_DEFINE (scm_with_fluids, "with-fluids*", 3, 0, 0,
(SCM fluids, SCM values, SCM thunk),
"Set @var{fluids} to @var{values} temporary, and call @var{thunk}.\n"
scm_c_with_fluids (SCM fluids, SCM values, SCM (*cproc) (), void *cdata)
#define FUNC_NAME "scm_c_with_fluids"
{
- SCM ans, data;
- long flen, vlen;
+ SCM wf, ans;
+ long flen, vlen, i;
+ SCM *fluidsv, *valuesv;
SCM_VALIDATE_LIST_COPYLEN (1, fluids, flen);
SCM_VALIDATE_LIST_COPYLEN (2, values, vlen);
if (flen != vlen)
scm_out_of_range (s_scm_with_fluids, values);
- if (flen == 1)
- return scm_c_with_fluid (SCM_CAR (fluids), SCM_CAR (values),
- cproc, cdata);
+ if (SCM_UNLIKELY (flen == 0))
+ return cproc (cdata);
+
+ fluidsv = alloca (sizeof(SCM)*flen);
+ valuesv = alloca (sizeof(SCM)*flen);
- data = scm_cons (fluids, values);
- scm_dynwind_begin (SCM_F_DYNWIND_REWINDABLE);
- scm_dynwind_rewind_handler_with_scm (swap_fluids, data,
- SCM_F_WIND_EXPLICITLY);
- scm_dynwind_unwind_handler_with_scm (swap_fluids_reverse, data,
- SCM_F_WIND_EXPLICITLY);
+ for (i = 0; i < flen; i++)
+ {
+ fluidsv[i] = SCM_CAR (fluids);
+ fluids = SCM_CDR (fluids);
+ valuesv[i] = SCM_CAR (values);
+ values = SCM_CDR (values);
+ }
+
+ wf = scm_i_make_with_fluids (flen, fluidsv, valuesv);
+ scm_i_swap_with_fluids (wf, SCM_I_CURRENT_THREAD->dynamic_state);
+ scm_i_set_dynwinds (scm_cons (wf, scm_i_dynwinds ()));
ans = cproc (cdata);
- scm_dynwind_end ();
+ scm_i_swap_with_fluids (wf, SCM_I_CURRENT_THREAD->dynamic_state);
+ scm_i_set_dynwinds (scm_cdr (scm_i_dynwinds ()));
+
return ans;
}
#undef FUNC_NAME
scm_c_with_fluid (SCM fluid, SCM value, SCM (*cproc) (), void *cdata)
#define FUNC_NAME "scm_c_with_fluid"
{
- SCM ans;
+ SCM ans, wf;
- scm_dynwind_begin (SCM_F_DYNWIND_REWINDABLE);
- scm_dynwind_fluid (fluid, value);
+ wf = scm_i_make_with_fluids (1, &fluid, &value);
+ scm_i_swap_with_fluids (wf, SCM_I_CURRENT_THREAD->dynamic_state);
+ scm_i_set_dynwinds (scm_cons (wf, scm_i_dynwinds ()));
ans = cproc (cdata);
- scm_dynwind_end ();
+ scm_i_swap_with_fluids (wf, SCM_I_CURRENT_THREAD->dynamic_state);
+ scm_i_set_dynwinds (scm_cdr (scm_i_dynwinds ()));
+
return ans;
}
#undef FUNC_NAME
scm_i_make_initial_dynamic_state ()
{
SCM fluids = scm_c_make_vector (allocated_fluids_len, SCM_BOOL_F);
- SCM state;
- SCM_NEWSMOB2 (state, tc16_dynamic_state,
- SCM_UNPACK (fluids), SCM_UNPACK (SCM_EOL));
- return state;
+ return scm_cell (scm_tc7_dynamic_state, SCM_UNPACK (fluids));
}
SCM_DEFINE (scm_make_dynamic_state, "make-dynamic-state", 0, 1, 0,
"or of the current dynamic state when @var{parent} is omitted.")
#define FUNC_NAME s_scm_make_dynamic_state
{
- SCM fluids, state;
+ SCM fluids;
if (SCM_UNBNDP (parent))
parent = scm_current_dynamic_state ();
- scm_assert_smob_type (tc16_dynamic_state, parent);
+ SCM_ASSERT (IS_DYNAMIC_STATE (parent), parent, SCM_ARG1, FUNC_NAME);
fluids = scm_vector_copy (DYNAMIC_STATE_FLUIDS (parent));
- SCM_NEWSMOB2 (state, tc16_dynamic_state,
- SCM_UNPACK (fluids), SCM_UNPACK (SCM_EOL));
-
- return state;
+ return scm_cell (scm_tc7_dynamic_state, SCM_UNPACK (fluids));
}
#undef FUNC_NAME
{
scm_i_thread *t = SCM_I_CURRENT_THREAD;
SCM old = t->dynamic_state;
- scm_assert_smob_type (tc16_dynamic_state, state);
+ SCM_ASSERT (IS_DYNAMIC_STATE (state), state, SCM_ARG1, FUNC_NAME);
t->dynamic_state = state;
return old;
}
scm_dynwind_current_dynamic_state (SCM state)
{
SCM loc = scm_cons (state, SCM_EOL);
- scm_assert_smob_type (tc16_dynamic_state, state);
+ SCM_ASSERT (IS_DYNAMIC_STATE (state), state, SCM_ARG1, NULL);
scm_dynwind_rewind_handler_with_scm (swap_dynamic_state, loc,
SCM_F_WIND_EXPLICITLY);
scm_dynwind_unwind_handler_with_scm (swap_dynamic_state, loc,
}
#undef FUNC_NAME
-void
-scm_fluids_prehistory ()
-{
- tc16_fluid = scm_make_smob_type ("fluid", 0);
- scm_set_smob_print (tc16_fluid, fluid_print);
-
- tc16_dynamic_state = scm_make_smob_type ("dynamic-state", 0);
-}
void
scm_init_fluids ()
HCoop / bpt / guile.git / blobdiff