[PATCH] dynarray: merge from glibc

[PATCH] dynarray: merge from glibc

[Paul Eggert]

This also helps document glibc’s direction in using GCC’s
memory-allocation checking.
* lib/cdefs.h: Omit comments that glibc rejected.
(__returns_nonnull, __attr_access_none, __attr_dealloc)
(__attr_dealloc_free): New macros.
* lib/libc-config.h: Undef the new macros that are defined
unconditionally.
* lib/malloc/dynarray_at_failure.c [_LIBC]: Do not include stdlib.h.
(__libc_dynarray_at_failure) [_LIBC]: Call __libc_fatal,
fixing a bad merge previously.
---
 ChangeLog                        | 14 ++++++++++++++
 lib/cdefs.h                      | 33 +++++++++++++++++++++++++++-----
 lib/libc-config.h                |  3 +++
 lib/malloc/dynarray_at_failure.c |  3 ++-
 4 files changed, 47 insertions(+), 6 deletions(-)

diff --git a/ChangeLog b/ChangeLog
index 8482276384..037fa7da4f 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,17 @@
+2021-08-11  Paul Eggert  <eggert@cs.ucla.edu>
+
+	dynarray: merge from glibc
+	This also helps document glibc’s direction in using GCC’s
+	memory-allocation checking.
+	* lib/cdefs.h: Omit comments that glibc rejected.
+	(__returns_nonnull, __attr_access_none, __attr_dealloc)
+	(__attr_dealloc_free): New macros.
+	* lib/libc-config.h: Undef the new macros that are defined
+	unconditionally.
+	* lib/malloc/dynarray_at_failure.c [_LIBC]: Do not include stdlib.h.
+	(__libc_dynarray_at_failure) [_LIBC]: Call __libc_fatal,
+	fixing a bad merge previously.
+
 2021-08-08  Bruno Haible  <bruno@clisp.org>
 
 	canonicalize-lgpl: Fix conflict with z/OS <sys/stat.h>.
diff --git a/lib/cdefs.h b/lib/cdefs.h
index b883b25666..4dac9d264d 100644
--- a/lib/cdefs.h
+++ b/lib/cdefs.h
@@ -261,10 +261,6 @@
 
 #if __GNUC_PREREQ (2,7) || __glibc_has_attribute (__unused__)
 # define __attribute_maybe_unused__ __attribute__ ((__unused__))
-/* Once the next version of the C standard comes out, we can
-   do something like the following here:
-   #elif defined __STDC_VERSION__ && 202???L <= __STDC_VERSION__
-   # define __attribute_maybe_unused__ [[__maybe_unused__]]   */
 #else
 # define __attribute_maybe_unused__ /* Ignore */
 #endif
@@ -336,6 +332,16 @@
 # define __nonnull(params) __attribute_nonnull__ (params)
 #endif
 
+/* The returns_nonnull function attribute marks the return type of the function
+   as always being non-null.  */
+#ifndef __returns_nonnull
+# if __GNUC_PREREQ (4, 9) || __glibc_has_attribute (__returns_nonnull__)
+# define __returns_nonnull __attribute__ ((__returns_nonnull__))
+# else
+# define __returns_nonnull
+# endif
+#endif
+
 /* If fortification mode, we warn about unused results of certain
    function calls which can lead to problems.  */
 #if __GNUC_PREREQ (3,4) || __glibc_has_attribute (__warn_unused_result__)
@@ -598,9 +604,26 @@ _Static_assert (0, "IEEE 128-bits long double requires redirection on this platf
    array according to access mode, or at least one element when
    size-index is not provided:
      access (access-mode, <ref-index> [, <size-index>])  */
-#define __attr_access(x) __attribute__ ((__access__ x))
+#  define __attr_access(x) __attribute__ ((__access__ x))
+#  if __GNUC_PREREQ (11, 0)
+#    define __attr_access_none(argno) __attribute__ ((__access__ (__none__, argno)))
+#  else
+#    define __attr_access_none(argno)
+#  endif
 #else
 #  define __attr_access(x)
+#  define __attr_access_none(argno)
+#endif
+
+#if __GNUC_PREREQ (11, 0)
+/* Designates dealloc as a function to call to deallocate objects
+   allocated by the declared function.  */
+# define __attr_dealloc(dealloc, argno) \
+    __attribute__ ((__malloc__ (dealloc, argno)))
+# define __attr_dealloc_free __attr_dealloc (__builtin_free, 1)
+#else
+# define __attr_dealloc(dealloc, argno)
+# define __attr_dealloc_free
 #endif
 
 /* Specify that a function such as setjmp or vfork may return
diff --git a/lib/libc-config.h b/lib/libc-config.h
index f68749fc74..886c11f37f 100644
--- a/lib/libc-config.h
+++ b/lib/libc-config.h
@@ -117,6 +117,9 @@
 # undef __THROW
 # undef __THROWNL
 # undef __attr_access
+# undef __attr_access_none
+# undef __attr_dealloc
+# undef __attr_dealloc_free
 # undef __attribute__
 # undef __attribute_alloc_size__
 # undef __attribute_artificial__
diff --git a/lib/malloc/dynarray_at_failure.c b/lib/malloc/dynarray_at_failure.c
index 4f840db7c5..8dd6850787 100644
--- a/lib/malloc/dynarray_at_failure.c
+++ b/lib/malloc/dynarray_at_failure.c
@@ -18,11 +18,11 @@
 
 #ifndef _LIBC
 # include <libc-config.h>
+# include <stdlib.h>
 #endif
 
 #include <dynarray.h>
 #include <stdio.h>
-#include <stdlib.h>
 
 void
 __libc_dynarray_at_failure (size_t size, size_t index)
@@ -32,6 +32,7 @@ __libc_dynarray_at_failure (size_t size, size_t index)
   __snprintf (buf, sizeof (buf), "Fatal glibc error: "
               "array index %zu not less than array length %zu\n",
               index, size);
+  __libc_fatal (buf);
 #else
  abort ();
 #endif
-- 
2.31.1