Merge the specpdl and backtrace stacks. Make the structure of the

specpdl entries more obvious via a tagged union of structs.
* src/lisp.h (BITS_PER_PTRDIFF_T): New constant.
(enum specbind_tag): New enum.
(struct specbinding): Make it a tagged union of structs.
Add a case for backtrace records.
(specpdl_symbol, specpdl_old_value, specpdl_where, specpdl_arg)
(specpdl_func, backtrace_function, backtrace_nargs, backtrace_args)
(backtrace_debug_on_exit): New accessors.
(struct backtrace): Remove.
(struct catchtag): Remove backlist field.
* src/data.c (let_shadows_buffer_binding_p, let_shadows_global_binding_p):
Move to eval.c.
(Flocal_variable_p): Speed up the common case where the binding is
already loaded.
* src/eval.c (backtrace_list): Remove.
(set_specpdl_symbol, set_specpdl_old_value): Remove.
(set_backtrace_args, set_backtrace_nargs)
(set_backtrace_debug_on_exit, backtrace_p, backtrace_top)
(backtrace_next): New functions.
(Fdefvaralias, Fdefvar): Adjust to new specpdl format.
(unwind_to_catch, internal_lisp_condition_case)
(internal_condition_case, internal_condition_case_1)
(internal_condition_case_2, internal_condition_case_n): Don't bother
with backtrace_list any more.
(Fsignal): Adjust to new backtrace format.
(grow_specpdl): Move up.
(record_in_backtrace): New function.
(eval_sub, Ffuncall): Use it.
(apply_lambda): Adjust to new backtrace format.
(let_shadows_buffer_binding_p, let_shadows_global_binding_p): Move from
data.c.
(specbind): Adjust to new specpdl format.  Simplify.
(record_unwind_protect, unbind_to): Adjust to new specpdl format.
(Fbacktrace_debug, Fbacktrace, Fbacktrace_frame): Adjust to new
backtrace format.
(mark_backtrace): Remove.
(mark_specpdl, get_backtrace, backtrace_top_function): New functions.
* src/xdisp.c (redisplay_internal): Use record_in_backtrace.
* src/alloc.c (Fgarbage_collect): Use record_in_backtrace.
Use mark_specpdl.
* src/profiler.c (record_backtrace): Use get_backtrace.
(handle_profiler_signal): Use backtrace_top_function.
* src/.gdbinit (xbacktrace, hookpost-backtrace): Use new backtrace
accessor functions.

1 files changed, 3 insertions, 14 deletions

diff --git a/src/profiler.c b/src/profiler.c
index 0a0a4d0bc57..aba81344c68 100644
--- a/src/profiler.c
+++ b/src/profiler.c
@@ -138,10 +138,8 @@ static void evict_lower_half (log_t *log)
 static void
 record_backtrace (log_t *log, EMACS_INT count)
 {
-  struct backtrace *backlist = backtrace_list;
   Lisp_Object backtrace;
-  ptrdiff_t index, i = 0;
-  ptrdiff_t asize;
+  ptrdiff_t index;
 
   if (!INTEGERP (log->next_free))
     /* FIXME: transfer the evicted counts to a special entry rather
@@ -151,16 +149,7 @@ record_backtrace (log_t *log, EMACS_INT count)
 
   /* Get a "working memory" vector.  */
   backtrace = HASH_KEY (log, index);
-  asize = ASIZE (backtrace);
-
-  /* Copy the backtrace contents into working memory.  */
-  for (; i < asize && backlist; i++, backlist = backlist->next)
-    /* FIXME: For closures we should ignore the environment.  */
-    ASET (backtrace, i, backlist->function);
-
-  /* Make sure that unused space of working memory is filled with nil.  */
-  for (; i < asize; i++)
-    ASET (backtrace, i, Qnil);
+  get_backtrace (backtrace);
 
   { /* We basically do a `gethash+puthash' here, except that we have to be
        careful to avoid memory allocation since we're in a signal
@@ -232,7 +221,7 @@ static EMACS_INT current_sampling_interval;
 static void
 handle_profiler_signal (int signal)
 {
-  if (backtrace_list && EQ (backtrace_list->function, Qautomatic_gc))
+  if (EQ (backtrace_top_function (), Qautomatic_gc))
     /* Special case the time-count inside GC because the hash-table
        code is not prepared to be used while the GC is running.
        More specifically it uses ASIZE at many places where it does