For glibc, implementing realloc (p, s) as realloc (p, s?s:1) suffices,
and it’s probably better to do it inline to aid static checking.
* lib/realloc.c (rpl_realloc) [_GL_INLINE_RPL_REALLOC]:
Remove, replacing with inline function in stdlib.h.
* lib/stdlib.in.h (_GL_INLINE_RPL_REALLOC): New macro.
(rpl_realloc): Define as inline if _GL_INLINE_RPL_REALLOC.
* m4/realloc.m4 (gl_FUNC_REALLOC_0_NONNULL):
Set REPLACE_REALLOC_FOR_REALLOC_POSIX=2 instead of 1,
if it’s close enough to glibc that the inline optimization is valid.
---
ChangeLog | 11 +++++++++++
lib/realloc.c | 24 ++++++++++++++----------
lib/stdlib.in.h | 10 ++++++++++
m4/realloc.m4 | 8 ++++++--
4 files changed, 41 insertions(+), 12 deletions(-)
diff --git a/ChangeLog b/ChangeLog
index d646381a86..1617f3b58b 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,5 +1,16 @@
2024-11-04 Paul Eggert <egg...@cs.ucla.edu>
+ realloc-posix: tune for glibc-like
+ For glibc, implementing realloc (p, s) as realloc (p, s?s:1) suffices,
+ and it’s probably better to do it inline to aid static checking.
+ * lib/realloc.c (rpl_realloc) [_GL_INLINE_RPL_REALLOC]:
+ Remove, replacing with inline function in stdlib.h.
+ * lib/stdlib.in.h (_GL_INLINE_RPL_REALLOC): New macro.
+ (rpl_realloc): Define as inline if _GL_INLINE_RPL_REALLOC.
+ * m4/realloc.m4 (gl_FUNC_REALLOC_0_NONNULL):
+ Set REPLACE_REALLOC_FOR_REALLOC_POSIX=2 instead of 1,
+ if it’s close enough to glibc that the inline optimization is valid.
+
realloc-posix: use _GL_USE_STDLIB_ALLOC
* lib/realloc.c (_GL_USE_STDLIB_ALLOC):
New macro, which we can use now that we don’t use malloc.
diff --git a/lib/realloc.c b/lib/realloc.c
index e1c971eb06..e1198cf633 100644
--- a/lib/realloc.c
+++ b/lib/realloc.c
@@ -30,6 +30,8 @@
# include <cheri.h>
#endif
+#ifndef _GL_INLINE_RPL_REALLOC
+
/* Change the size of an allocated block of memory P to N bytes,
with error checking. If P is NULL, use malloc. Otherwise if N is zero,
free P and return NULL. */
@@ -41,7 +43,7 @@ rpl_realloc (void *p, size_t n)
if (n == 0)
{
-#if NEED_SANITIZED_REALLOC
+# if NEED_SANITIZED_REALLOC
/* When P is non-null, ISO C23 §7.24.3.7.(3) says realloc (P, 0) has
undefined behavior even though C17 and earlier partially defined
the behavior. Let the programmer know.
@@ -52,7 +54,7 @@ rpl_realloc (void *p, size_t n)
we can revisit this code. */
if (p != NULL)
abort ();
-#endif
+# endif
/* realloc (NULL, 0) acts like glibc malloc (0), i.e., like malloc (1)
except the caller cannot dereference any non-null return.
@@ -74,31 +76,33 @@ rpl_realloc (void *p, size_t n)
matches BSD and V7 realloc, and requires no extra code at
caller sites. */
-#if !HAVE_REALLOC_0_NONNULL
+# if !HAVE_REALLOC_0_NONNULL
n1 = 1;
-#endif
+# endif
}
-#if !HAVE_MALLOC_PTRDIFF
+# if !HAVE_MALLOC_PTRDIFF
ptrdiff_t signed_n;
if (ckd_add (&signed_n, n, 0))
{
errno = ENOMEM;
return NULL;
}
-#endif
+# endif
void *result = realloc (p, n1);
-#if !HAVE_MALLOC_POSIX
+# if !HAVE_MALLOC_POSIX
if (result == NULL)
errno = ENOMEM;
-#endif
+# endif
-#ifdef __CHERI_PURE_CAPABILITY__
+# ifdef __CHERI_PURE_CAPABILITY__
if (result != NULL)
result = cheri_bounds_set (result, n);
-#endif
+# endif
return result;
}
+
+#endif
diff --git a/lib/stdlib.in.h b/lib/stdlib.in.h
index 0d5c076d06..7344157263 100644
--- a/lib/stdlib.in.h
+++ b/lib/stdlib.in.h
@@ -1461,14 +1461,24 @@ _GL_WARN_ON_USE (setstate_r, "setstate_r is unportable
- "
#if @GNULIB_REALLOC_POSIX@
# if @REPLACE_REALLOC_FOR_REALLOC_POSIX@
+# if @REPLACE_REALLOC_FOR_REALLOC_POSIX@ == 2
+# define _GL_INLINE_RPL_REALLOC 1
+_GL_STDLIB_INLINE void *
+rpl_realloc (void *ptr, size_t size)
+{
+ return realloc (ptr, size ? size : 1);
+}
+# endif
# if !((defined __cplusplus && defined GNULIB_NAMESPACE) \
|| _GL_USE_STDLIB_ALLOC)
# undef realloc
# define realloc rpl_realloc
# endif
+# if @REPLACE_REALLOC_FOR_REALLOC_POSIX@ != 2
_GL_FUNCDECL_RPL (realloc, void *,
(void *ptr, size_t size),
_GL_ATTRIBUTE_DEALLOC_FREE _GL_ATTRIBUTE_NODISCARD);
+# endif
_GL_CXXALIAS_RPL (realloc, void *, (void *ptr, size_t size));
# else
# if __GNUC__ >= 11 && !defined __clang__
diff --git a/m4/realloc.m4 b/m4/realloc.m4
index 4a3f2ea8ae..f34cc4c389 100644
--- a/m4/realloc.m4
+++ b/m4/realloc.m4
@@ -1,5 +1,5 @@
# realloc.m4
-# serial 38
+# serial 39
dnl Copyright (C) 2007, 2009-2024 Free Software Foundation, Inc.
dnl This file is free software; the Free Software Foundation
dnl gives unlimited permission to copy and/or distribute it,
@@ -73,5 +73,9 @@ AC_DEFUN([gl_FUNC_REALLOC_0_NONNULL],
[*yes],
[AC_DEFINE([HAVE_REALLOC_0_NONNULL], [1],
[Define to 1 if realloc (..., 0) returns nonnull.])],
- [REPLACE_REALLOC_FOR_REALLOC_POSIX=1])
+
[AS_CASE([$gl_cv_func_realloc_sanitize,$gl_cv_malloc_ptrdiff,$gl_cv_func_malloc_posix,$host],
+ [yes,*,*,* | *,no,*,* | *,*,*no,* | *,*,*,aarch64c-*-freebsd*],
+ [REPLACE_REALLOC_FOR_REALLOC_POSIX=1],
+ [# Optimize for common case of glibc 2.1.1+ and compatibles.
+ REPLACE_REALLOC_FOR_REALLOC_POSIX=2])])
])
--
2.43.0
