Bump to m4 1.4.19

[platform/upstream/m4.git] / lib / malloca.h

diff --git a/lib/malloca.h b/lib/malloca.h
index 6fbe45e..6b6a52c 100644 (file)
--- a/lib/malloca.h
+++ b/lib/malloca.h
@@ -1,5 +1,5 @@
 /* Safe automatic memory allocation.
-   Copyright (C) 2003-2007, 2009-2013 Free Software Foundation, Inc.
+   Copyright (C) 2003-2007, 2009-2021 Free Software Foundation, Inc.
    Written by Bruno Haible <bruno@clisp.org>, 2003.
 
    This program is free software; you can redistribute it and/or modify
@@ -13,7 +13,7 @@
    GNU General Public License for more details.
 
    You should have received a copy of the GNU General Public License
-   along with this program; if not, see <http://www.gnu.org/licenses/>.  */
+   along with this program; if not, see <https://www.gnu.org/licenses/>.  */
 
 #ifndef _MALLOCA_H
 #define _MALLOCA_H
@@ -21,6 +21,9 @@
 #include <alloca.h>
 #include <stddef.h>
 #include <stdlib.h>
+#include <stdint.h>
+
+#include "xalloc-oversized.h"
 
 
 #ifdef __cplusplus
@@ -53,8 +56,10 @@ extern "C" {
    the function returns.  Upon failure, it returns NULL.  */
 #if HAVE_ALLOCA
 # define malloca(N) \
-  ((N) < 4032 - sa_increment                                        \
-   ? (void *) ((char *) alloca ((N) + sa_increment) + sa_increment) \
+  ((N) < 4032 - (2 * sa_alignment_max - 1)                                   \
+   ? (void *) (((uintptr_t) (char *) alloca ((N) + 2 * sa_alignment_max - 1) \
+                + (2 * sa_alignment_max - 1))                                \
+               & ~(uintptr_t)(2 * sa_alignment_max - 1))                     \
    : mmalloca (N))
 #else
 # define malloca(N) \
@@ -71,17 +76,10 @@ extern void freea (void *p);
 
 /* nmalloca(N,S) is an overflow-safe variant of malloca (N * S).
    It allocates an array of N objects, each with S bytes of memory,
-   on the stack.  S must be positive and N must be nonnegative.
+   on the stack.  N and S should be nonnegative and free of side effects.
    The array must be freed using freea() before the function returns.  */
-#if 1
-/* Cf. the definition of xalloc_oversized.  */
-# define nmalloca(n, s) \
-    ((n) > (size_t) (sizeof (ptrdiff_t) <= sizeof (size_t) ? -1 : -2) / (s) \
-     ? NULL \
-     : malloca ((n) * (s)))
-#else
-extern void * nmalloca (size_t n, size_t s);
-#endif
+#define nmalloca(n, s) \
+  (xalloc_oversized (n, s) ? NULL : malloca ((n) * (size_t) (s)))
 
 
 #ifdef __cplusplus
@@ -92,7 +90,7 @@ extern void * nmalloca (size_t n, size_t s);
 /* ------------------- Auxiliary, non-public definitions ------------------- */
 
 /* Determine the alignment of a type at compile time.  */
-#if defined __GNUC__ || defined __IBM__ALIGNOF__
+#if defined __GNUC__ || defined __clang__ || defined __IBM__ALIGNOF__
 # define sa_alignof __alignof__
 #elif defined __cplusplus
   template <class type> struct sa_alignof_helper { char __slot1; type __slot2; };
@@ -115,19 +113,12 @@ enum
    among all elementary types.  */
   sa_alignment_long = sa_alignof (long),
   sa_alignment_double = sa_alignof (double),
-#if HAVE_LONG_LONG_INT
   sa_alignment_longlong = sa_alignof (long long),
-#endif
   sa_alignment_longdouble = sa_alignof (long double),
   sa_alignment_max = ((sa_alignment_long - 1) | (sa_alignment_double - 1)
-#if HAVE_LONG_LONG_INT
                       | (sa_alignment_longlong - 1)
-#endif
                       | (sa_alignment_longdouble - 1)
-                     ) + 1,
-/* The increment that guarantees room for a magic word must be >= sizeof (int)
-   and a multiple of sa_alignment_max.  */
-  sa_increment = ((sizeof (int) + sa_alignment_max - 1) / sa_alignment_max) * sa_alignment_max
+                     ) + 1
 };
 
 #endif /* _MALLOCA_H */