From b0d36494797b08d7cc7a9c62c2c1a748297a7aaf Mon Sep 17 00:00:00 2001
From: nobu <nobu@b2dd03c8-39d4-4d8f-98ff-823fe69b080e>
Date: Mon, 17 Apr 2017 00:10:45 +0000
Subject: gc.c: PREVENT_STACK_OVERFLOW

* gc.c (PREVENT_STACK_OVERFLOW): define TRUE to try preventing
  stack overflow before actually happens.

* gc.c (stack_check): parameterize thread pointer.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@58374 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
---
 gc.c | 18 +++++++++++-------
 1 file changed, 11 insertions(+), 7 deletions(-)

diff --git a/gc.c b/gc.c
index ce80ccff7f..ef4770a797 100644
--- a/gc.c
+++ b/gc.c
@@ -3937,12 +3937,18 @@ ruby_stack_length(VALUE **p)
     return STACK_LENGTH;
 }
 
+#ifndef PREVENT_STACK_OVERFLOW
 #if !(defined(POSIX_SIGNAL) && defined(SIGSEGV) && defined(HAVE_SIGALTSTACK))
+# define PREVENT_STACK_OVERFLOW 1
+#else
+# define PREVENT_STACK_OVERFLOW 0
+#endif
+#endif
+#if PREVENT_STACK_OVERFLOW
 static int
-stack_check(int water_mark)
+stack_check(rb_thread_t *th, int water_mark)
 {
     int ret;
-    rb_thread_t *th = GET_THREAD();
     SET_STACK_END;
     ret = STACK_LENGTH > STACK_LEVEL_MAX - water_mark;
 #ifdef __ia64
@@ -3953,6 +3959,8 @@ stack_check(int water_mark)
 #endif
     return ret;
 }
+#else
+#define stack_check(th, water_mark) FALSE
 #endif
 
 #define STACKFRAME_FOR_CALL_CFUNC 512
@@ -3960,11 +3968,7 @@ stack_check(int water_mark)
 int
 ruby_stack_check(void)
 {
-#if defined(POSIX_SIGNAL) && defined(SIGSEGV) && defined(HAVE_SIGALTSTACK)
-    return 0;
-#else
-    return stack_check(STACKFRAME_FOR_CALL_CFUNC);
-#endif
+    return stack_check(GET_THREAD(), STACKFRAME_FOR_CALL_CFUNC);
 }
 
 ATTRIBUTE_NO_ADDRESS_SAFETY_ANALYSIS
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