Miscellaneous enhancements to scratch/correct-warning-pos.

1. Check the type (symbol with position) of the argument given to the native
compiled version of SYMBOL_WITH_POS_SYM.
2. Handle infinite recursion caused by circular lists, etc., in
macroexp-strip-symbol-positions by using hash tables.
3. Read byte compiled functions without giving symbols positions.

* lisp/emacs-lisp/comp.el (comp-finalize-relocs): Add symbol-with-pos-p into
the list of relocated symbols.

* lisp/emacs-lisp/macroexp.el (macroexp--ssp-conses-seen)
(macroexp--ssp-vectors-seen, macroexp--ssp-records-seen): Renamed, and
animated as hash tables.
(macroexp--strip-s-p-2): Optionally tests for the presence of an argument in
one of the above hash tables, so as to handle otherwise infinite recursion.
(byte-compile-strip-s-p-1): Add a condition-case to handle infinite recursion
caused by circular lists etc., using the above hash tables as required.

* src/comp.c (comp_t): New element symbol_with_pos_sym.
(emit_SYMBOL_WITH_POS_SYM): Amend just to call the new SYMBOL_WITH_POS_SYM.
(emit_CHECK_SYMBOL_WITH_POS, define_SYMBOL_WITH_POS_SYM): New functions.
(Fcomp__init_ctxt): Register an emitter for Qsymbol_with_pos_p.
(Fcomp__compile_ctxt_to_file): Call define_SYMBOL_WITH_POS_SYM.
(syms_of_comp): Define Qsymbol_with_pos_p.

* src/data.c (syms_of_data): Define a new error symbol Qrecursion_error, an
error category for the new error symbols Qexcessive_variable_binding and
Qexcessive_lisp_nesting.

* src/eval.c (grow_specpdl): Change the signal_error call to an xsignal0 call
using the new error symbol Qexcessive_variable_binding.
(eval_sub, Ffuncall): Change the `error' calls to xsignal using the new error
symbol Qexcessive_lisp_nesting.

* src/lread.c (read1): When reading a compiled function, read the components
of the vector without giving its symbols a position.

1 files changed, 3 insertions, 4 deletions

diff --git a/src/eval.c b/src/eval.c
index 94ad0607732..5cb673ab223 100644
--- a/src/eval.c
+++ b/src/eval.c
@@ -2398,8 +2398,7 @@ grow_specpdl (void)
 	  if (max_specpdl_size < 400)
 	    max_size = max_specpdl_size = 400;
 	  if (max_size <= specpdl_size)
-	    signal_error ("Variable binding depth exceeds max-specpdl-size",
-			  Qnil);
+	    xsignal0 (Qexcessive_variable_binding);
 	}
       pdlvec = xpalloc (pdlvec, &pdlvecsize, 1, max_size + 1, sizeof *specpdl);
       specpdl = pdlvec + 1;
@@ -2453,7 +2452,7 @@ eval_sub (Lisp_Object form)
       if (max_lisp_eval_depth < 100)
 	max_lisp_eval_depth = 100;
       if (lisp_eval_depth > max_lisp_eval_depth)
-	error ("Lisp nesting exceeds `max-lisp-eval-depth'");
+	xsignal0 (Qexcessive_lisp_nesting);
     }
 
   Lisp_Object original_fun = XCAR (form);
@@ -3044,7 +3043,7 @@ usage: (funcall FUNCTION &rest ARGUMENTS)  */)
       if (max_lisp_eval_depth < 100)
 	max_lisp_eval_depth = 100;
       if (lisp_eval_depth > max_lisp_eval_depth)
-	error ("Lisp nesting exceeds `max-lisp-eval-depth'");
+	xsignal0 (Qexcessive_lisp_nesting);
     }
 
   count = record_in_backtrace (args[0], &args[1], nargs - 1);