master fe26495: Drop support for -fcheck-pointer-bounds

[Paul Eggert]

branch: master
commit fe2649528b0b7637e6b6851c41e696a1016d8d53
Author: Paul Eggert <eggert@cs.ucla.edu>
Commit: Paul Eggert <eggert@cs.ucla.edu>

    Drop support for -fcheck-pointer-bounds
    
    GCC has removed the -fcheck-pointer bounds option, and the Linux
    kernel has also removed support for Intel MPX, so there’s no point
    to keeping this debugging option within Emacs.
    * src/bytecode.c (BYTE_CODE_THREADED):
    * src/lisp.h (DEFINE_LISP_SYMBOL, XSYMBOL, make_lisp_symbol):
    Assume __CHKP__ is not defined.
    * src/ptr-bounds.h: Remove.  All uses of ptr_bounds_clip,
    ptr_bounds_copy, ptr_bounds_init, ptr_bounds_set removed.
---
 etc/NEWS         |  5 ++++
 src/alloc.c      | 31 ++++++++--------------
 src/bytecode.c   | 11 +++-----
 src/callint.c    |  4 ---
 src/dispnew.c    |  7 -----
 src/editfns.c    |  3 ---
 src/emacs.c      |  1 -
 src/frame.c      |  6 -----
 src/fringe.c     |  5 +---
 src/gmalloc.c    | 16 +++---------
 src/lisp.h       | 31 +++++-----------------
 src/ptr-bounds.h | 79 --------------------------------------------------------
 12 files changed, 31 insertions(+), 168 deletions(-)

diff --git a/etc/NEWS b/etc/NEWS
index cd5cc2c..f135b3f 100644
--- a/etc/NEWS
+++ b/etc/NEWS
@@ -59,6 +59,11 @@ shaping, so 'configure' now recommends that combination.
 It was declared obsolete in Emacs 27.1.
 
 ---
+** Support for building with '-fcheck-pointer-bounds' has been removed.
+GCC has withdrawn the '-fcheck-pointer-bounds' option and support for
+its implementation has been removed from the Linux kernel.
+
+---
 ** Emacs no longer supports old OpenBSD systems.
 OpenBSD 5.3 and older releases are no longer supported, as they lack
 proper pty support that Emacs needs.
diff --git a/src/alloc.c b/src/alloc.c
index 3a02ef3..b16b2f8 100644
--- a/src/alloc.c
+++ b/src/alloc.c
@@ -34,7 +34,6 @@ along with GNU Emacs.  If not, see 
<https://www.gnu.org/licenses/>.  */
 #include "bignum.h"
 #include "dispextern.h"
 #include "intervals.h"
-#include "ptr-bounds.h"
 #include "puresize.h"
 #include "sheap.h"
 #include "sysstdio.h"
@@ -1624,8 +1623,7 @@ static struct Lisp_String *string_free_list;
    a pointer to the `u.data' member of its sdata structure; the
    structure starts at a constant offset in front of that.  */
 
-#define SDATA_OF_STRING(S) ((sdata *) ptr_bounds_init ((S)->u.s.data \
-                                                      - SDATA_DATA_OFFSET))
+#define SDATA_OF_STRING(S) ((sdata *) ((S)->u.s.data - SDATA_DATA_OFFSET))
 
 
 #ifdef GC_CHECK_STRING_OVERRUN
@@ -1799,7 +1797,7 @@ allocate_string (void)
          /* Every string on a free list should have NULL data pointer.  */
          s->u.s.data = NULL;
          NEXT_FREE_LISP_STRING (s) = string_free_list;
-         string_free_list = ptr_bounds_clip (s, sizeof *s);
+         string_free_list = s;
        }
     }
 
@@ -1908,7 +1906,7 @@ allocate_string_data (struct Lisp_String *s,
 
   MALLOC_UNBLOCK_INPUT;
 
-  s->u.s.data = ptr_bounds_clip (SDATA_DATA (data), nbytes + 1);
+  s->u.s.data = SDATA_DATA (data);
 #ifdef GC_CHECK_STRING_BYTES
   SDATA_NBYTES (data) = nbytes;
 #endif
@@ -2036,7 +2034,7 @@ sweep_strings (void)
 
                  /* Put the string on the free-list.  */
                  NEXT_FREE_LISP_STRING (s) = string_free_list;
-                 string_free_list = ptr_bounds_clip (s, sizeof *s);
+                 string_free_list = s;
                  ++nfree;
                }
            }
@@ -2044,7 +2042,7 @@ sweep_strings (void)
            {
              /* S was on the free-list before.  Put it there again.  */
              NEXT_FREE_LISP_STRING (s) = string_free_list;
-             string_free_list = ptr_bounds_clip (s, sizeof *s);
+             string_free_list = s;
              ++nfree;
            }
        }
@@ -2171,8 +2169,7 @@ compact_small_strings (void)
                    {
                      eassert (tb != b || to < from);
                      memmove (to, from, size + GC_STRING_EXTRA);
-                     to->string->u.s.data
-                       = ptr_bounds_clip (SDATA_DATA (to), nbytes + 1);
+                     to->string->u.s.data = SDATA_DATA (to);
                    }
 
                  /* Advance past the sdata we copied to.  */
@@ -2959,7 +2956,6 @@ Lisp_Object zero_vector;
 static void
 setup_on_free_list (struct Lisp_Vector *v, ptrdiff_t nbytes)
 {
-  v = ptr_bounds_clip (v, nbytes);
   eassume (header_size <= nbytes);
   ptrdiff_t nwords = (nbytes - header_size) / word_size;
   XSETPVECTYPESIZE (v, PVEC_FREE, 0, nwords);
@@ -3307,7 +3303,7 @@ allocate_vectorlike (ptrdiff_t len, bool clearit)
 
   MALLOC_UNBLOCK_INPUT;
 
-  return ptr_bounds_clip (p, nbytes);
+  return p;
 }
 
 
@@ -4461,7 +4457,6 @@ live_string_holding (struct mem_node *m, void *p)
      must not be on the free-list.  */
   if (0 <= offset && offset < sizeof b->strings)
     {
-      cp = ptr_bounds_copy (cp, b);
       struct Lisp_String *s = p = cp -= offset % sizeof b->strings[0];
       if (s->u.s.data)
        return s;
@@ -4494,7 +4489,6 @@ live_cons_holding (struct mem_node *m, void *p)
       && (b != cons_block
          || offset / sizeof b->conses[0] < cons_block_index))
     {
-      cp = ptr_bounds_copy (cp, b);
       struct Lisp_Cons *s = p = cp -= offset % sizeof b->conses[0];
       if (!deadp (s->u.s.car))
        return s;
@@ -4528,7 +4522,6 @@ live_symbol_holding (struct mem_node *m, void *p)
       && (b != symbol_block
          || offset / sizeof b->symbols[0] < symbol_block_index))
     {
-      cp = ptr_bounds_copy (cp, b);
       struct Lisp_Symbol *s = p = cp -= offset % sizeof b->symbols[0];
       if (!deadp (s->u.s.function))
        return s;
@@ -5234,7 +5227,7 @@ pure_alloc (size_t size, int type)
   pure_bytes_used = pure_bytes_used_lisp + pure_bytes_used_non_lisp;
 
   if (pure_bytes_used <= pure_size)
-    return ptr_bounds_clip (result, size);
+    return result;
 
   /* Don't allocate a large amount here,
      because it might get mmap'd and then its address
@@ -5325,7 +5318,7 @@ find_string_data_in_pure (const char *data, ptrdiff_t 
nbytes)
       /* Check the remaining characters.  */
       if (memcmp (data, non_lisp_beg + start, nbytes) == 0)
        /* Found.  */
-       return ptr_bounds_clip (non_lisp_beg + start, nbytes + 1);
+       return non_lisp_beg + start;
 
       start += last_char_skip;
     }
@@ -6049,7 +6042,6 @@ garbage_collect (void)
              stack_copy = xrealloc (stack_copy, stack_size);
              stack_copy_size = stack_size;
            }
-         stack = ptr_bounds_set (stack, stack_size);
          no_sanitize_memcpy (stack_copy, stack, stack_size);
        }
     }
@@ -6885,8 +6877,7 @@ sweep_conses (void)
 
               for (pos = start; pos < stop; pos++)
                 {
-                 struct Lisp_Cons *acons
-                   = ptr_bounds_copy (&cblk->conses[pos], cblk);
+                 struct Lisp_Cons *acons = &cblk->conses[pos];
                  if (!XCONS_MARKED_P (acons))
                     {
                       this_free++;
@@ -6939,7 +6930,7 @@ sweep_floats (void)
       int this_free = 0;
       for (int i = 0; i < lim; i++)
        {
-         struct Lisp_Float *afloat = ptr_bounds_copy (&fblk->floats[i], fblk);
+         struct Lisp_Float *afloat = &fblk->floats[i];
          if (!XFLOAT_MARKED_P (afloat))
            {
              this_free++;
diff --git a/src/bytecode.c b/src/bytecode.c
index 5ac30aa..1913a48 100644
--- a/src/bytecode.c
+++ b/src/bytecode.c
@@ -24,7 +24,6 @@ along with GNU Emacs.  If not, see 
<https://www.gnu.org/licenses/>.  */
 #include "character.h"
 #include "buffer.h"
 #include "keyboard.h"
-#include "ptr-bounds.h"
 #include "syntax.h"
 #include "window.h"
 
@@ -47,7 +46,7 @@ along with GNU Emacs.  If not, see 
<https://www.gnu.org/licenses/>.  */
    indirect threaded, using GCC's computed goto extension.  This code,
    as currently implemented, is incompatible with BYTE_CODE_SAFE and
    BYTE_CODE_METER.  */
-#if (defined __GNUC__ && !defined __STRICT_ANSI__ && !defined __CHKP__ \
+#if (defined __GNUC__ && !defined __STRICT_ANSI__ \
      && !BYTE_CODE_SAFE && !defined BYTE_CODE_METER)
 #define BYTE_CODE_THREADED
 #endif
@@ -368,14 +367,12 @@ exec_byte_code (Lisp_Object bytestr, Lisp_Object vector, 
Lisp_Object maxdepth,
   USE_SAFE_ALLOCA;
   void *alloc;
   SAFE_ALLOCA_LISP_EXTRA (alloc, stack_items, bytestr_length);
-  ptrdiff_t item_bytes = stack_items * word_size;
-  Lisp_Object *stack_base = ptr_bounds_clip (alloc, item_bytes);
+  Lisp_Object *stack_base = alloc;
   Lisp_Object *top = stack_base;
   *top = vector; /* Ensure VECTOR survives GC (Bug#33014).  */
   Lisp_Object *stack_lim = stack_base + stack_items;
-  unsigned char *bytestr_data = alloc;
-  bytestr_data = ptr_bounds_clip (bytestr_data + item_bytes, bytestr_length);
-  memcpy (bytestr_data, SDATA (bytestr), bytestr_length);
+  unsigned char const *bytestr_data = memcpy (stack_lim,
+                                             SDATA (bytestr), bytestr_length);
   unsigned char const *pc = bytestr_data;
   ptrdiff_t count = SPECPDL_INDEX ();
 
diff --git a/src/callint.c b/src/callint.c
index eb91635..f609c96 100644
--- a/src/callint.c
+++ b/src/callint.c
@@ -21,7 +21,6 @@ along with GNU Emacs.  If not, see 
<https://www.gnu.org/licenses/>.  */
 #include <config.h>
 
 #include "lisp.h"
-#include "ptr-bounds.h"
 #include "character.h"
 #include "buffer.h"
 #include "keyboard.h"
@@ -440,9 +439,6 @@ invoke it (via an `interactive' spec that contains, for 
instance, an
   signed char *varies = (signed char *) (visargs + nargs);
 
   memclear (args, nargs * (2 * word_size + 1));
-  args = ptr_bounds_clip (args, nargs * sizeof *args);
-  visargs = ptr_bounds_clip (visargs, nargs * sizeof *visargs);
-  varies = ptr_bounds_clip (varies, nargs * sizeof *varies);
 
   if (!NILP (enable))
     specbind (Qenable_recursive_minibuffers, Qt);
diff --git a/src/dispnew.c b/src/dispnew.c
index 1ae59e3..d318e26 100644
--- a/src/dispnew.c
+++ b/src/dispnew.c
@@ -25,7 +25,6 @@ along with GNU Emacs.  If not, see 
<https://www.gnu.org/licenses/>.  */
 #include <unistd.h>
 
 #include "lisp.h"
-#include "ptr-bounds.h"
 #include "termchar.h"
 /* cm.h must come after dispextern.h on Windows.  */
 #include "dispextern.h"
@@ -4891,12 +4890,6 @@ scrolling (struct frame *frame)
   unsigned *new_hash = old_hash + height;
   int *draw_cost = (int *) (new_hash + height);
   int *old_draw_cost = draw_cost + height;
-  old_hash = ptr_bounds_clip (old_hash, height * sizeof *old_hash);
-  new_hash = ptr_bounds_clip (new_hash, height * sizeof *new_hash);
-  draw_cost = ptr_bounds_clip (draw_cost, height * sizeof *draw_cost);
-  old_draw_cost = ptr_bounds_clip (old_draw_cost,
-                                  height * sizeof *old_draw_cost);
-
   eassert (current_matrix);
 
   /* Compute hash codes of all the lines.  Also calculate number of
diff --git a/src/editfns.c b/src/editfns.c
index 763d95b..cb09ea8 100644
--- a/src/editfns.c
+++ b/src/editfns.c
@@ -46,7 +46,6 @@ along with GNU Emacs.  If not, see 
<https://www.gnu.org/licenses/>.  */
 
 #include "composite.h"
 #include "intervals.h"
-#include "ptr-bounds.h"
 #include "systime.h"
 #include "character.h"
 #include "buffer.h"
@@ -3131,8 +3130,6 @@ styled_format (ptrdiff_t nargs, Lisp_Object *args, bool 
message)
      string was not copied into the output.
      It is 2 if byte I was not the first byte of its character.  */
   char *discarded = (char *) &info[nspec_bound];
-  info = ptr_bounds_clip (info, info_size);
-  discarded = ptr_bounds_clip (discarded, formatlen);
   memset (discarded, 0, formatlen);
 
   /* Try to determine whether the result should be multibyte.
diff --git a/src/emacs.c b/src/emacs.c
index 8a6bb3a..8e5eaf5 100644
--- a/src/emacs.c
+++ b/src/emacs.c
@@ -83,7 +83,6 @@ along with GNU Emacs.  If not, see 
<https://www.gnu.org/licenses/>.  */
 #include "charset.h"
 #include "composite.h"
 #include "dispextern.h"
-#include "ptr-bounds.h"
 #include "regex-emacs.h"
 #include "sheap.h"
 #include "syntax.h"
diff --git a/src/frame.c b/src/frame.c
index c871e4f..c21d470 100644
--- a/src/frame.c
+++ b/src/frame.c
@@ -35,7 +35,6 @@ along with GNU Emacs.  If not, see 
<https://www.gnu.org/licenses/>.  */
 #include "buffer.h"
 /* These help us bind and responding to switch-frame events.  */
 #include "keyboard.h"
-#include "ptr-bounds.h"
 #include "frame.h"
 #include "blockinput.h"
 #include "termchar.h"
@@ -5019,8 +5018,6 @@ gui_display_get_resource (Display_Info *dpyinfo, 
Lisp_Object attribute,
   USE_SAFE_ALLOCA;
   char *name_key = SAFE_ALLOCA (name_keysize + class_keysize);
   char *class_key = name_key + name_keysize;
-  name_key = ptr_bounds_clip (name_key, name_keysize);
-  class_key = ptr_bounds_clip (class_key, class_keysize);
 
   /* Start with emacs.FRAMENAME for the name (the specific one)
      and with `Emacs' for the class key (the general one).  */
@@ -5091,9 +5088,6 @@ x_get_resource_string (const char *attribute, const char 
*class)
   ptrdiff_t class_keysize = sizeof (EMACS_CLASS) - 1 + strlen (class) + 2;
   char *name_key = SAFE_ALLOCA (name_keysize + class_keysize);
   char *class_key = name_key + name_keysize;
-  name_key = ptr_bounds_clip (name_key, name_keysize);
-  class_key = ptr_bounds_clip (class_key, class_keysize);
-
   esprintf (name_key, "%s.%s", SSDATA (Vinvocation_name), attribute);
   sprintf (class_key, "%s.%s", EMACS_CLASS, class);
 
diff --git a/src/fringe.c b/src/fringe.c
index fc4c738..c3d64fe 100644
--- a/src/fringe.c
+++ b/src/fringe.c
@@ -23,7 +23,6 @@ along with GNU Emacs.  If not, see 
<https://www.gnu.org/licenses/>.  */
 
 #include "lisp.h"
 #include "frame.h"
-#include "ptr-bounds.h"
 #include "window.h"
 #include "dispextern.h"
 #include "buffer.h"
@@ -1607,9 +1606,7 @@ If BITMAP already exists, the existing definition is 
replaced.  */)
   fb.dynamic = true;
 
   xfb = xmalloc (sizeof fb + fb.height * BYTES_PER_BITMAP_ROW);
-  fb.bits = b = ((unsigned short *)
-                ptr_bounds_clip (xfb + 1, fb.height * BYTES_PER_BITMAP_ROW));
-  xfb = ptr_bounds_clip (xfb, sizeof *xfb);
+  fb.bits = b = (unsigned short *) (xfb + 1);
 
   j = 0;
   while (j < fb.height)
diff --git a/src/gmalloc.c b/src/gmalloc.c
index 8450a63..3560c74 100644
--- a/src/gmalloc.c
+++ b/src/gmalloc.c
@@ -38,8 +38,6 @@ License along with this library.  If not, see 
<https://www.gnu.org/licenses/>.
 
 #include "lisp.h"
 
-#include "ptr-bounds.h"
-
 #ifdef HAVE_MALLOC_H
 # if GNUC_PREREQ (4, 2, 0)
 #  pragma GCC diagnostic ignored "-Wdeprecated-declarations"
@@ -200,8 +198,7 @@ extern size_t _bytes_free;
 
 /* Internal versions of `malloc', `realloc', and `free'
    used when these functions need to call each other.
-   They are the same but don't call the hooks
-   and don't bound the resulting pointers.  */
+   They are the same but don't call the hooks.  */
 extern void *_malloc_internal (size_t);
 extern void *_realloc_internal (void *, size_t);
 extern void _free_internal (void *);
@@ -551,7 +548,7 @@ malloc_initialize_1 (void)
   _heapinfo[0].free.size = 0;
   _heapinfo[0].free.next = _heapinfo[0].free.prev = 0;
   _heapindex = 0;
-  _heapbase = (char *) ptr_bounds_init (_heapinfo);
+  _heapbase = (char *) _heapinfo;
   _heaplimit = BLOCK (_heapbase + heapsize * sizeof (malloc_info));
 
   register_heapinfo ();
@@ -912,8 +909,7 @@ malloc (size_t size)
      among multiple threads.  We just leave it for compatibility with
      glibc malloc (i.e., assignments to gmalloc_hook) for now.  */
   hook = gmalloc_hook;
-  void *result = (hook ? hook : _malloc_internal) (size);
-  return ptr_bounds_clip (result, size);
+  return (hook ? hook : _malloc_internal) (size);
 }
 
 #if !(defined (_LIBC) || defined (HYBRID_MALLOC))
@@ -991,7 +987,6 @@ _free_internal_nolock (void *ptr)
 
   if (ptr == NULL)
     return;
-  ptr = ptr_bounds_init (ptr);
 
   PROTECT_MALLOC_STATE (0);
 
@@ -1303,7 +1298,6 @@ _realloc_internal_nolock (void *ptr, size_t size)
   else if (ptr == NULL)
     return _malloc_internal_nolock (size);
 
-  ptr = ptr_bounds_init (ptr);
   block = BLOCK (ptr);
 
   PROTECT_MALLOC_STATE (0);
@@ -1426,8 +1420,7 @@ realloc (void *ptr, size_t size)
     return NULL;
 
   hook = grealloc_hook;
-  void *result = (hook ? hook : _realloc_internal) (ptr, size);
-  return ptr_bounds_clip (result, size);
+  return (hook ? hook : _realloc_internal) (ptr, size);
 }
 /* Copyright (C) 1991, 1992, 1994 Free Software Foundation, Inc.
 
@@ -1601,7 +1594,6 @@ aligned_alloc (size_t alignment, size_t size)
        {
          l->exact = result;
          result = l->aligned = (char *) result + adj;
-         result = ptr_bounds_clip (result, size);
        }
       UNLOCK_ALIGNED_BLOCKS ();
       if (l == NULL)
diff --git a/src/lisp.h b/src/lisp.h
index 22ddf3e..17b92a0 100644
--- a/src/lisp.h
+++ b/src/lisp.h
@@ -893,8 +893,8 @@ verify (GCALIGNED (struct Lisp_Symbol));
    convert it to a Lisp_Word.  */
 #if LISP_WORDS_ARE_POINTERS
 /* untagged_ptr is a pointer so that the compiler knows that TAG_PTR
-   yields a pointer; this can help with gcc -fcheck-pointer-bounds.
-   It is char * so that adding a tag uses simple machine addition.  */
+   yields a pointer.  It is char * so that adding a tag uses simple
+   machine addition.  */
 typedef char *untagged_ptr;
 typedef uintptr_t Lisp_Word_tag;
 #else
@@ -922,13 +922,9 @@ typedef EMACS_UINT Lisp_Word_tag;
    when using a debugger like GDB, on older platforms where the debug
    format does not represent C macros.  However, they are unbounded
    and would just be asking for trouble if checking pointer bounds.  */
-#ifdef __CHKP__
-# define DEFINE_LISP_SYMBOL(name)
-#else
-# define DEFINE_LISP_SYMBOL(name) \
-   DEFINE_GDB_SYMBOL_BEGIN (Lisp_Object, name) \
-   DEFINE_GDB_SYMBOL_END (LISPSYM_INITIALLY (name))
-#endif
+#define DEFINE_LISP_SYMBOL(name) \
+  DEFINE_GDB_SYMBOL_BEGIN (Lisp_Object, name) \
+  DEFINE_GDB_SYMBOL_END (LISPSYM_INITIALLY (name))
 
 /* The index of the C-defined Lisp symbol SYM.
    This can be used in a static initializer.  */
@@ -1002,30 +998,15 @@ XSYMBOL (Lisp_Object a)
   eassert (SYMBOLP (a));
   intptr_t i = (intptr_t) XUNTAG (a, Lisp_Symbol, struct Lisp_Symbol);
   void *p = (char *) lispsym + i;
-#ifdef __CHKP__
-  /* Bypass pointer checking.  Although this could be improved it is
-     probably not worth the trouble.  */
-  p = __builtin___bnd_set_ptr_bounds (p, sizeof (struct Lisp_Symbol));
-#endif
   return p;
 }
 
 INLINE Lisp_Object
 make_lisp_symbol (struct Lisp_Symbol *sym)
 {
-#ifdef __CHKP__
-  /* Although '__builtin___bnd_narrow_ptr_bounds (sym, sym, sizeof *sym)'
-     should be more efficient, it runs afoul of GCC bug 83251
-     <https://gcc.gnu.org/bugzilla/show_bug.cgi?id=83251>.
-     Also, attempting to call __builtin___bnd_chk_ptr_bounds (sym, sizeof *sym)
-     here seems to trigger a GCC bug, as yet undiagnosed.  */
-  char *addr = __builtin___bnd_set_ptr_bounds (sym, sizeof *sym);
-  char *symoffset = addr - (intptr_t) lispsym;
-#else
-  /* If !__CHKP__, GCC 7 x86-64 generates faster code if lispsym is
+  /* GCC 7 x86-64 generates faster code if lispsym is
      cast to char * rather than to intptr_t.  */
   char *symoffset = (char *) ((char *) sym - (char *) lispsym);
-#endif
   Lisp_Object a = TAG_PTR (Lisp_Symbol, symoffset);
   eassert (XSYMBOL (a) == sym);
   return a;
diff --git a/src/ptr-bounds.h b/src/ptr-bounds.h
deleted file mode 100644
index 22d49f2..0000000
--- a/src/ptr-bounds.h
+++ /dev/null
@@ -1,79 +0,0 @@
-/* Pointer bounds checking for GNU Emacs
-
-Copyright 2017-2020 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 */