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.

1 files changed, 7 insertions, 0 deletions

diff --git a/NEWS b/NEWS
index 96cc959d9..d70397e97 100644
--- a/NEWS
+++ b/NEWS
@@ -23,6 +23,13 @@ guile2.2, guile-2, guile2, and then guile.  The found prefix is also
 applied to guild, guile-config, and the like.  Thanks to Freja Nordsiek
 for this work.
 
+** Add thread-local fluids
+
+Guile now has support for fluids whose values are not captured by
+`current-dynamic-state' and not inheritied by child threads, and thus
+are local to the kernel thread they run on.  See "Thread-Local
+Variables" in the manual, for more.
+
 * Bug fixes
 
 ** Fix type inference when multiplying flonum with complex