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diff --git a/src/ptr-bounds.h b/src/ptr-bounds.h
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+/* Pointer bounds checking for GNU Emacs
+
+Copyright 2017-2018 Free Software Foundation, Inc.
+
+This file is part of GNU Emacs.
+
+GNU Emacs is free software: you can redistribute it and/or modify
+it under the terms of the GNU General Public License as published by
+the Free Software Foundation, either version 3 of the License, or (at
+your option) any later version.
+
+GNU Emacs is distributed in the hope that it will be useful,
+but WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+GNU General Public License for more details.
+
+You should have received a copy of the GNU General Public License
+along with GNU Emacs.  If not, see <https://www.gnu.org/licenses/>.  */
+
+/* Pointer bounds checking is a no-op unless running on hardware
+   supporting Intel MPX (Intel Skylake or better).  Also, it requires
+   GCC 5 and Linux kernel 3.19, or later.  Configure with
+   CFLAGS='-fcheck-pointer-bounds -mmpx', perhaps with
+   -fchkp-first-field-has-own-bounds thrown in.
+
+   Although pointer bounds checking can help during debugging, it is
+   disabled by default because it hurts performance significantly.
+   The checking does not detect all pointer errors.  For example, a
+   dumped Emacs might not detect a bounds violation of a pointer that
+   was created before Emacs was dumped.  */
+
+#ifndef PTR_BOUNDS_H
+#define PTR_BOUNDS_H
+
+#include <stddef.h>
+
+/* When not checking pointer bounds, the following macros simply
+   return their first argument.  These macros return either void *, or
+   the same type as their first argument.  */
+
+INLINE_HEADER_BEGIN
+
+/* Return a copy of P, with bounds narrowed to [P, P + N).  */
+#ifdef __CHKP__
+INLINE void *
+ptr_bounds_clip (void const *p, size_t n)
+{
+  return __builtin___bnd_narrow_ptr_bounds (p, p, n);
+}
+#else
+# define ptr_bounds_clip(p, n) ((void) (size_t) {n}, p)
+#endif
+
+/* Return a copy of P, but with the bounds of Q.  */
+#ifdef __CHKP__
+# define ptr_bounds_copy(p, q) __builtin___bnd_copy_ptr_bounds (p, q)
+#else
+# define ptr_bounds_copy(p, q) ((void) (void const *) {q}, p)
+#endif
+
+/* Return a copy of P, but with infinite bounds.
+   This is a loophole in pointer bounds checking.  */
+#ifdef __CHKP__
+# define ptr_bounds_init(p) __builtin___bnd_init_ptr_bounds (p)
+#else
+# define ptr_bounds_init(p) (p)
+#endif
+
+/* Return a copy of P, but with bounds [P, P + N).
+   This is a loophole in pointer bounds checking.  */
+#ifdef __CHKP__
+# define ptr_bounds_set(p, n) __builtin___bnd_set_ptr_bounds (p, n)
+#else
+# define ptr_bounds_set(p, n) ((void) (size_t) {n}, p)
+#endif
+
+INLINE_HEADER_END
+
+#endif /* PTR_BOUNDS_H */