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, 0 insertions, 2 deletions

diff --git a/debug.c b/debug.c
index 677a9457..00117558 100644
--- a/debug.c
+++ b/debug.c
@@ -45,7 +45,6 @@
 
 int opt_debugger;
 int debug_depth;
-val debug_block_s;
 static int step_mode;
 static int next_depth = -1;
 static val breakpoints;
@@ -246,7 +245,6 @@ void debug_init(void)
 {
   step_mode = 1;
   protect(&breakpoints, &last_command, convert(val *, 0));
-  debug_block_s = intern(lit("debug-block"), system_package);
   {
     char *columns = getenv("COLUMNS");
     if (columns)