Ligher weight debug instrumentation.

This speeds up the TXR Lisp interpreter, because do_eval
sets up a debug frame and uses debug_return.

* debug.c (debug_block_s): Symbol removed.
(debug_init): Remove initialization of debug_block_s.

* debug.h (debug_block_s): Declaration removed.
(debug_enter): Do not establish a named block or a catch block;
no time-wasting unwind stack manipulation at all.
The debug_depth variable is managed by the extended setjmp
context now.  Provide a return value variable, and a well-defined name to
branch to to exit from the debug block.
(debug_return): Do not use heavy-weight uw_block_return;
simply set the return variable and branch to debug_return_out
label.

* signal.h (EJ_DBG_MEMB, EJ_DBG_SAVE, EJ_DBG_REST,
EJ_OPT_MEMB, EJ_OPT_SAVE, EJ_OPT_REST): New macros.
(extended_jmp_buf): Define optional global state
variables using EJ_OPT_MEMB.
(extended_setjmp): Save and restore optional
globals using EJ_OPT_SAVE and EJ_OPT_RESTORE.
Now debug_depth is saved and restored if
debugging support is compiled in.

* match.c (open_data_source): Remove bogus debug_return
invocations which were uncovered here by changes to the macro.

* eval.c (do_eval, expand_macro): debug_return must now be after
debug_end, because it won't dynamically clean up frames that it doesn't
know about. The set_dyn_env is no longer unreachable in expand_macro;
it is now necessary because debug_return isn't doing the longjmp
that previously restored dyn_env.

1 files changed, 5 insertions, 3 deletions

diff --git a/eval.c b/eval.c
index 908a8b20..45962114 100644
--- a/eval.c
+++ b/eval.c
@@ -1057,8 +1057,8 @@ static val do_eval(val form, val env, val ctx_form,
         last_form_evaled = form;
         ret = apply(cdr(fbinding), z(args), form);
         last_form_evaled = lfe_save;
-        debug_return (ret);
         debug_end;
+        debug_return (ret);
       }
     }
   } else {
@@ -1461,10 +1461,12 @@ static val expand_macro(val form, val expander, val menv)
     val body = cdr(cdr(cdr(expander)));
     val saved_de = set_dyn_env(make_env(nil, nil, dyn_env));
     val exp_env = bind_macro_params(env, menv, params, args, nil, form);
+    val result;
     debug_frame(name, args, nil, env, nil, nil, nil);
-    debug_return(eval_progn(body, exp_env, body));
+    result = eval_progn(body, exp_env, body);
     debug_end;
-    set_dyn_env(saved_de); /* not reached but shuts up compiler */
+    set_dyn_env(saved_de);
+    debug_return(result);
     debug_leave;
   }
 }