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authorAndy Wingo <wingo@pobox.com>2017-03-07 20:57:59 +0100
committerAndy Wingo <wingo@pobox.com>2017-03-07 21:15:39 +0100
commitfb8c91a35c0a1c357aab96a6721a8b65c93368b0 (patch)
tree2071a8a79753305d413ce2c70c084902e9cd7044 /libguile/fluids.c
parent84a740d86a5afd235f1b47ac66c88db010b1d56b (diff)
downloadguile-fb8c91a35c0a1c357aab96a6721a8b65c93368b0.tar.gz
Add thread local fluids
* libguile/fluids.h (struct scm_dynamic_state): Add thread_local_values table. Thread locals are flushed to a separate thread-local table. The references are strong references since the table never escapes the thread. (scm_make_thread_local_fluid, scm_fluid_thread_local_p): New functions. * libguile/fluids.c (FLUID_F_THREAD_LOCAL): (SCM_I_FLUID_THREAD_LOCAL_P): New macros. (restore_dynamic_state): Add comment about precondition. (save_dynamic_state): Flush thread locals. (scm_i_fluid_print): Print thread locals nicely. (new_fluid): Add flags arg. (scm_make_fluid, scm_make_fluid_with_default, scm_make_unbound_fluid): Adapt. (scm_make_thread_local_fluid, scm_fluid_thread_local_p): New functions. (fluid_set_x): Special flushing logic for thread-locals. (fluid_ref): Special cache miss logic for thread locals. * libguile/stacks.c (scm_init_stacks): * libguile/throw.c (scm_init_throw): %stacks and %exception-handler are thread-locals. * libguile/threads.c (guilify_self_2): Init thread locals table. * test-suite/tests/fluids.test ("dynamic states"): Add test. * doc/ref/api-control.texi (Fluids and Dynamic States): Add link to Thread-Local Variables. * doc/ref/api-scheduling.texi (Thread Local Variables): Update with real thread-locals. * NEWS: Update.
Diffstat (limited to 'libguile/fluids.c')
-rw-r--r--libguile/fluids.c77
1 files changed, 67 insertions, 10 deletions
diff --git a/libguile/fluids.c b/libguile/fluids.c
index 7daad7781..6bdca7ddf 100644
--- a/libguile/fluids.c
+++ b/libguile/fluids.c
@@ -91,6 +91,10 @@
table could share more state, as in an immutable weak array-mapped
hash trie or something, but we don't have such a data structure. */
+#define FLUID_F_THREAD_LOCAL 0x100
+#define SCM_I_FLUID_THREAD_LOCAL_P(x) \
+ (SCM_CELL_WORD_0 (x) & FLUID_F_THREAD_LOCAL)
+
static inline int
is_dynamic_state (SCM x)
{
@@ -103,6 +107,8 @@ get_dynamic_state (SCM dynamic_state)
return SCM_CELL_OBJECT_1 (dynamic_state);
}
+/* Precondition: It's OK to throw away any unflushed data in the current
+ cache. */
static inline void
restore_dynamic_state (SCM saved, scm_t_dynamic_state *state)
{
@@ -133,9 +139,20 @@ save_dynamic_state (scm_t_dynamic_state *state)
struct scm_cache_entry *entry = &state->cache.entries[slot];
SCM key = SCM_PACK (entry->key);
SCM value = SCM_PACK (entry->value);
- if (entry->key &&
- !scm_is_eq (scm_weak_table_refq (state->values, key, SCM_UNDEFINED),
- value))
+
+ if (!entry->key)
+ continue;
+ if (SCM_I_FLUID_THREAD_LOCAL_P (key))
+ {
+ /* Because we don't include unflushed thread-local fluids in
+ the result, we need to flush them to the table so that
+ restore_dynamic_state can just throw away the current
+ cache. */
+ scm_hashq_set_x (state->thread_local_values, key, value);
+ }
+ else if (!scm_is_eq (scm_weak_table_refq (state->values, key,
+ SCM_UNDEFINED),
+ value))
{
if (state->has_aliased_values)
saved = scm_acons (key, value, saved);
@@ -177,7 +194,10 @@ copy_value_table (SCM tab)
void
scm_i_fluid_print (SCM exp, SCM port, scm_print_state *pstate SCM_UNUSED)
{
- scm_puts ("#<fluid ", port);
+ if (SCM_I_FLUID_THREAD_LOCAL_P (exp))
+ scm_puts ("#<thread-local-fluid ", port);
+ else
+ scm_puts ("#<fluid ", port);
scm_intprint (SCM_UNPACK (exp), 16, port);
scm_putc ('>', port);
}
@@ -196,15 +216,15 @@ scm_i_dynamic_state_print (SCM exp, SCM port, scm_print_state *pstate SCM_UNUSED
#define SCM_I_FLUID_DEFAULT(x) (SCM_CELL_OBJECT_1 (x))
static SCM
-new_fluid (SCM init)
+new_fluid (SCM init, scm_t_bits flags)
{
- return scm_cell (scm_tc7_fluid, SCM_UNPACK (init));
+ return scm_cell (scm_tc7_fluid | flags, SCM_UNPACK (init));
}
SCM
scm_make_fluid (void)
{
- return new_fluid (SCM_BOOL_F);
+ return new_fluid (SCM_BOOL_F, 0);
}
SCM_DEFINE (scm_make_fluid_with_default, "make-fluid", 0, 1, 0,
@@ -219,7 +239,7 @@ SCM_DEFINE (scm_make_fluid_with_default, "make-fluid", 0, 1, 0,
"with its own dynamic state, you can use fluids for thread local storage.")
#define FUNC_NAME s_scm_make_fluid_with_default
{
- return new_fluid (SCM_UNBNDP (dflt) ? SCM_BOOL_F : dflt);
+ return new_fluid (SCM_UNBNDP (dflt) ? SCM_BOOL_F : dflt, 0);
}
#undef FUNC_NAME
@@ -228,7 +248,22 @@ SCM_DEFINE (scm_make_unbound_fluid, "make-unbound-fluid", 0, 0, 0,
"Make a fluid that is initially unbound.")
#define FUNC_NAME s_scm_make_unbound_fluid
{
- return new_fluid (SCM_UNDEFINED);
+ return new_fluid (SCM_UNDEFINED, 0);
+}
+#undef FUNC_NAME
+
+SCM_DEFINE (scm_make_thread_local_fluid, "make-thread-local-fluid", 0, 1, 0,
+ (SCM dflt),
+ "Return a newly created fluid, whose initial value is @var{dflt},\n"
+ "or @code{#f} if @var{dflt} is not given. Unlike fluids made\n"
+ "with @code{make-fluid}, thread local fluids are not captured\n"
+ "by @code{make-dynamic-state}. Similarly, a newly spawned\n"
+ "child thread does not inherit thread-local fluid values from\n"
+ "the parent thread.")
+#define FUNC_NAME s_scm_make_thread_local_fluid
+{
+ return new_fluid (SCM_UNBNDP (dflt) ? SCM_BOOL_F : dflt,
+ FLUID_F_THREAD_LOCAL);
}
#undef FUNC_NAME
@@ -242,6 +277,17 @@ SCM_DEFINE (scm_fluid_p, "fluid?", 1, 0, 0,
}
#undef FUNC_NAME
+SCM_DEFINE (scm_fluid_thread_local_p, "fluid-thread-local?", 1, 0, 0,
+ (SCM fluid),
+ "Return @code{#t} if the fluid @var{fluid} is is thread local,\n"
+ "or @code{#f} otherwise.")
+#define FUNC_NAME s_scm_fluid_thread_local_p
+{
+ SCM_VALIDATE_FLUID (1, fluid);
+ return scm_from_bool (SCM_I_FLUID_THREAD_LOCAL_P (fluid));
+}
+#undef FUNC_NAME
+
int
scm_is_fluid (SCM obj)
{
@@ -268,6 +314,12 @@ fluid_set_x (scm_t_dynamic_state *dynamic_state, SCM fluid, SCM value)
fluid = SCM_PACK (evicted.key);
value = SCM_PACK (evicted.value);
+ if (SCM_I_FLUID_THREAD_LOCAL_P (fluid))
+ {
+ scm_hashq_set_x (dynamic_state->thread_local_values, fluid, value);
+ return;
+ }
+
if (dynamic_state->has_aliased_values)
{
if (scm_is_eq (scm_weak_table_refq (dynamic_state->values,
@@ -294,7 +346,12 @@ fluid_ref (scm_t_dynamic_state *dynamic_state, SCM fluid)
val = SCM_PACK (entry->value);
else
{
- val = scm_weak_table_refq (dynamic_state->values, fluid, SCM_UNDEFINED);
+ if (SCM_I_FLUID_THREAD_LOCAL_P (fluid))
+ val = scm_hashq_ref (dynamic_state->thread_local_values, fluid,
+ SCM_UNDEFINED);
+ else
+ val = scm_weak_table_refq (dynamic_state->values, fluid,
+ SCM_UNDEFINED);
if (SCM_UNBNDP (val))
val = SCM_I_FLUID_DEFAULT (fluid);