From 9dee1c884eb50ba282eb9dd2495c5269add25963 Mon Sep 17 00:00:00 2001
From: Paul Eggert
Date: Fri, 14 Jul 2017 04:54:05 -0700
Subject: Improve stack-overflow heuristic on GNU/Linux

Problem reported by Steve Kemp (Bug#27585).
* src/eval.c (near_C_stack_top): Remove.  All uses replaced
by current_thread->stack_top.
(record_in_backtrace): Set current_thread->stack_top.
This is for when the Lisp interpreter calls itself.
* src/lread.c (read1): Set current_thread->stack_top.
This is for recursive s-expression reads.
* src/print.c (print_object): Set current_thread->stack_top.
This is for recursive s-expression printing.
* src/thread.c (mark_one_thread): Get stack top first.
* src/thread.h (struct thread_state.stack_top): Now void *, not char *.
---
 src/eval.c | 9 +--------
 1 file changed, 1 insertion(+), 8 deletions(-)

(limited to 'src/eval.c')

diff --git a/src/eval.c b/src/eval.c
index 8f293c9d300..e5900382dee 100644
--- a/src/eval.c
+++ b/src/eval.c
@@ -213,13 +213,6 @@ backtrace_next (union specbinding *pdl)
   return pdl;
 }
 
-/* Return a pointer to somewhere near the top of the C stack.  */
-void *
-near_C_stack_top (void)
-{
-  return backtrace_args (backtrace_top ());
-}
-
 void
 init_eval_once (void)
 {
@@ -2090,7 +2083,7 @@ record_in_backtrace (Lisp_Object function, Lisp_Object *args, ptrdiff_t nargs)
   specpdl_ptr->bt.kind = SPECPDL_BACKTRACE;
   specpdl_ptr->bt.debug_on_exit = false;
   specpdl_ptr->bt.function = function;
-  specpdl_ptr->bt.args = args;
+  current_thread->stack_top = specpdl_ptr->bt.args = args;
   specpdl_ptr->bt.nargs = nargs;
   grow_specpdl ();
 
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