From 8f452530e61b299d4d48f82f41ab5364723607ae Mon Sep 17 00:00:00 2001
From: Rickard Green <rickard@erlang.org>
Date: Wed, 5 Apr 2017 14:32:16 +0200
Subject: Stack guard for PCRE

---
 erts/emulator/beam/utils.c | 47 ++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 47 insertions(+)

(limited to 'erts/emulator/beam/utils.c')

diff --git a/erts/emulator/beam/utils.c b/erts/emulator/beam/utils.c
index d90c282c7e..d91ae1ffe6 100644
--- a/erts/emulator/beam/utils.c
+++ b/erts/emulator/beam/utils.c
@@ -5031,6 +5031,53 @@ Uint64 erts_timestamp_millis(void)
 #endif
 }
 
+void *
+erts_calc_stacklimit(char *prev_c, UWord stacksize)
+{
+    /*
+     * We *don't* want this function inlined, i.e., it is
+     * risky to call this function from another function
+     * in utils.c
+     */
+
+    UWord pagesize = erts_sys_get_page_size();
+    char c;
+    char *start;
+    if (&c > prev_c) {
+        start = (char *) ((((UWord) prev_c) / pagesize) * pagesize);
+        return (void *) (start + stacksize);
+    }
+    else {
+        start = (char *) (((((UWord) prev_c) - 1) / pagesize + 1) * pagesize);
+        return (void *) (start - stacksize);
+    }
+}
+
+/*
+ * erts_check_below_limit() and
+ * erts_check_above_limit() are put
+ * in utils.c in order to prevent
+ * inlining.
+ */
+
+int
+erts_check_below_limit(char *ptr, char *limit)
+{
+    return ptr < limit;
+}
+
+int
+erts_check_above_limit(char *ptr, char *limit)
+{
+    return ptr > limit;
+}
+
+void *
+erts_ptr_id(void *ptr)
+{
+    return ptr;
+}
+
 #ifdef DEBUG
 /*
  * Handy functions when using a debugger - don't use in the code!
-- 
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