debugger: initial backtrace support.

* debug.c (debug_state): Switch to unsigned, since this is now
a bitmask.
(sys_print_backtrace_s): New symbol variable.
(dbg_clear, dbg_set, dbg_restore): New static functions.
(debug_init): Initialize sys_print_backtrace_s. Register
dbg-clear, dbg-set, dbg-restore intrinsics. Register
dbg-enable, dbg-step, dbg-backtrace and dbg-all bitmask
variables, Lisp equivalents of DBG_ENABLE, DBG_SETP,
DBG_BACKTRACE and DBG_ALL.
(debug_dump_backtrace): New function.

* debug.h (opt_debugger): Declaration removed.
(debug_state): Declaration updated.
(DBG_ENABLE, DBG_STEP, DBG_BACKTRACE, DBG_ALL): New
preprocessor symbols.
(debug_set_state): Inline function removed.
(debug_clear, debug_set, debug_restore): New inline functions.
(dbg_backtrace, dbg_fcall_begin, dbg_fcall_end): New macros.
(debug_dump_backtrace): Declared.

* eval.c (error_trace): Invoke debug_dump_backtrace if support
is compiled in and backtraces are enabled.

* lib.c (do_generic_funcall): New function, copy of
generic_funcall.
(generic_funcall): Now a wrapper for do_generic_funcall which
registers fcall frames if backtrace support is enabled.
(funcall, funcall1, funcall2, funcall3, funcall4): Route to
slow generic_funcall path if backtraces are enabled.

* lisplib.c (debugger_instantiate, debugger_set_entries):
New static functions.
(lisplib_init): Autload support for debug module via above
new functions.
(lisplib_try_load): Save and restore debugger state in new
way using debug_set and debug_restore, with specific mask
values.

* parser.y (parse_once): Disable debugging in new way.

* share/txr/stdlib/debug.tl New file.

* sighal.h (EJ_DBG_MEMB, EJ_DBG_SAVE, EJ_DBG_REST): New
macros for saving/restoring debug state.
(EJ_OPT_MEMB, EJ_OPT_SAVE, EJ_OPT_REST): Reference the above
macros to include debug state in extended jump context.

* txr.c (help): Document --backtrace and that that -d
implies --backtrace.
(txr_main): Enable debugger using debug_set.
Provide new --backtrace option to enable backtraces only.

* unwind.c (args_s): New symbol variable.
(fcall_frame_type): New static variable.
(unwind_to_exit_point): Save pointer to original frame stack
and restore it when calling error_trace.  This is so that
error_trace can walk the stack to collect a backtrace.
(uw_find_frames_by_mask, uw_push_fcall): New functions.
(uw_late_init): Initialize args_s and fcall_frame_type.
gc-protect fcall_frame_type. Register uw-* variables
corresponding to the UW_* frame types.

* unwind.h (uw_frtype_t): New enum constant UW_FCALL.
(struct uw_fcall): New frame structure.
(union uw_frame): New member fc.
(uw_push_fcall, uw_find_frames_by_mask): Declared.

1 files changed, 24 insertions, 1 deletions

diff --git a/unwind.h b/unwind.h
index edf079ee..58e8c5fd 100644
--- a/unwind.h
+++ b/unwind.h
@@ -28,7 +28,10 @@
 typedef union uw_frame uw_frame_t;
 typedef enum uw_frtype {
   UW_BLOCK, UW_CAPTURED_BLOCK, UW_MENV, UW_CATCH, UW_HANDLE,
-  UW_CONT_COPY, UW_GUARD
+  UW_CONT_COPY, UW_GUARD,
+#if CONFIG_DEBUG_SUPPORT
+  UW_FCALL,
+#endif
 } uw_frtype_t;
 
 struct uw_common {
@@ -88,6 +91,17 @@ struct uw_guard {
   int uw_ok;
 };
 
+#if CONFIG_DEBUG_SUPPORT
+
+struct uw_fcall {
+  uw_frame_t *up;
+  uw_frtype_t type;
+  val fun;
+  struct args *args;
+};
+
+#endif
+
 #if __aarch64__
 #define UW_FRAME_ALIGN __attribute__ ((aligned (16)))
 #else
@@ -102,6 +116,9 @@ union uw_frame {
   struct uw_handler ha;
   struct uw_cont_copy cp;
   struct uw_guard gu;
+#if CONFIG_DEBUG_SUPPORT
+  struct uw_fcall fc;
+#endif
 } UW_FRAME_ALIGN;
 
 void uw_push_block(uw_frame_t *, val tag);
@@ -118,6 +135,9 @@ INLINE val uw_block_return(val tag, val result)
 val uw_block_abscond(val tag, val result);
 void uw_push_catch(uw_frame_t *, val matches);
 void uw_push_handler(uw_frame_t *, val matches, val fun);
+#if CONFIG_DEBUG_SUPPORT
+void uw_push_fcall(uw_frame_t *, val fun, struct args *args);
+#endif
 noreturn val uw_throw(val sym, val exception);
 noreturn val uw_throwv(val sym, struct args *);
 noreturn val uw_throwf(val sym, val fmt, ...);
@@ -143,6 +163,9 @@ uw_frame_t *uw_current_exit_point(void);
 val uw_get_frames(void);
 val uw_find_frame(val extype, val frtype);
 val uw_find_frames(val extype, val frtype);
+#if CONFIG_DEBUG_SUPPORT
+val uw_find_frames_by_mask(val mask);
+#endif
 val uw_invoke_catch(val catch_frame, val sym, struct args *);
 val uw_muffle_warning(val exc, struct args *);
 val uw_trace_error(val ctx, val exc, struct args *);