malloc: add indirection for malloc(-like) functions in tests [BZ #32366]

GCC 15 introduces allocation dead code removal (DCE) for PR117370 in
r15-5255-g7828dc070510f8. This breaks various glibc tests which want
to assert various properties of the allocator without doing anything
obviously useful with the allocated memory.

Alexander Monakov rightly pointed out that we can and should do better
than passing -fno-malloc-dce to paper over the problem. Not least because
GCC 14 already does such DCE where there's no testing of malloc's return
value against NULL, and LLVM has such optimisations too.

Handle this by providing malloc (and friends) wrappers with a volatile
function pointer to obscure that we're calling malloc (et. al) from the
compiler.

Reviewed-by: Paul Eggert <eggert@cs.ucla.edu>
(cherry picked from commit a9944a52c967ce76a5894c30d0274b824df43c7a)

diff --git a/malloc/tst-aligned-alloc.c b/malloc/tst-aligned-alloc.c
index 8bd6527147eb8760d7ba1356e98a7fbcd48b66e3..39f0cd22c09e61e0f0591cd60b595c33fb30d892 100644 (file)
--- a/malloc/tst-aligned-alloc.c
+++ b/malloc/tst-aligned-alloc.c
@@ -25,6 +25,8 @@
 #include <libc-diag.h>
 #include <support/check.h>
 
+#include "tst-malloc-aux.h"
+
 static int
 do_test (void)
 {

diff --git a/malloc/tst-compathooks-off.c b/malloc/tst-compathooks-off.c
index 134d7ea1075480937d29d90d3259114d6e66e5e6..cd8043d6f5ae4072bb2cb56e9dfb15ea4cb8a6a4 100644 (file)
--- a/malloc/tst-compathooks-off.c
+++ b/malloc/tst-compathooks-off.c
@@ -25,6 +25,8 @@
 #include <support/check.h>
 #include <support/support.h>
 
+#include "tst-malloc-aux.h"
+
 extern void (*volatile __free_hook) (void *, const void *);
 extern void *(*volatile __malloc_hook)(size_t, const void *);
 extern void *(*volatile __realloc_hook)(void *, size_t, const void *);

diff --git a/malloc/tst-malloc-aux.h b/malloc/tst-malloc-aux.h
new file mode 100644 (file)
index 0000000..54908b4
--- /dev/null
+++ b/malloc/tst-malloc-aux.h
@@ -0,0 +1,41 @@
+/* Wrappers for malloc-like functions to allow testing the implementation
+   without optimization.
+   Copyright (C) 2024 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public License as
+   published by the Free Software Foundation; either version 2.1 of the
+   License, or (at your option) any later version.
+
+   The GNU C Library 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
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; see the file COPYING.LIB.  If
+   not, see <https://www.gnu.org/licenses/>.  */
+
+#ifndef TST_MALLOC_AUX_H
+#define TST_MALLOC_AUX_H
+
+#include <stddef.h>
+#include <stdlib.h>
+
+static void *(*volatile aligned_alloc_indirect)(size_t, size_t) = aligned_alloc;
+static void *(*volatile calloc_indirect)(size_t, size_t) = calloc;
+static void *(*volatile malloc_indirect)(size_t) = malloc;
+static void *(*volatile realloc_indirect)(void*, size_t) = realloc;
+
+#undef aligned_alloc
+#undef calloc
+#undef malloc
+#undef realloc
+
+#define aligned_alloc aligned_alloc_indirect
+#define calloc calloc_indirect
+#define malloc malloc_indirect
+#define realloc realloc_indirect
+
+#endif /* TST_MALLOC_AUX_H */

diff --git a/malloc/tst-malloc-check.c b/malloc/tst-malloc-check.c
index df9fd67c13709e6be8ea6dd799edf9c2ad2a775e..18c6f28f8011bc3a2989413c4ba9abab02ab8d2c 100644 (file)
--- a/malloc/tst-malloc-check.c
+++ b/malloc/tst-malloc-check.c
@@ -20,6 +20,8 @@
 #include <stdlib.h>
 #include <libc-diag.h>
 
+#include "tst-malloc-aux.h"
+
 static int errors = 0;
 
 static void

diff --git a/malloc/tst-malloc-too-large.c b/malloc/tst-malloc-too-large.c
index 5be6800b890c8cf03dba5a169bdc91c99a838380..44979018b84cfd88865fce18a1fed1c02e1a753c 100644 (file)
--- a/malloc/tst-malloc-too-large.c
+++ b/malloc/tst-malloc-too-large.c
@@ -43,6 +43,7 @@
 #include <unistd.h>
 #include <sys/param.h>
 
+#include "tst-malloc-aux.h"
 
 /* This function prepares for each 'too-large memory allocation' test by
    performing a small successful malloc/free and resetting errno prior to

diff --git a/malloc/tst-malloc.c b/malloc/tst-malloc.c
index 0da5a8f263bbb30266a388e1c640718a613498c9..7b337e6e09d32e4cca9e60c4e68c17571182ba72 100644 (file)
--- a/malloc/tst-malloc.c
+++ b/malloc/tst-malloc.c
@@ -20,6 +20,8 @@
 #include <stdio.h>
 #include <libc-diag.h>
 
+#include "tst-malloc-aux.h"
+
 static int errors = 0;
 
 static void

diff --git a/malloc/tst-realloc.c b/malloc/tst-realloc.c
index fb661d312e11b411d5d7f90c34ac35677283e56d..b35a5a21250ab32936deec965de6cb04b37a37a1 100644 (file)
--- a/malloc/tst-realloc.c
+++ b/malloc/tst-realloc.c
@@ -23,6 +23,8 @@
 #include <libc-diag.h>
 #include <support/check.h>
 
+#include "tst-malloc-aux.h"
+
 static int
 do_test (void)
 {

diff --git a/support/support.h b/support/support.h
index b7f76bf080986b8f0a3b357b0c3bca0b97847ac0..3742f26b5500610ca6bfead761f2781a8b61dc58 100644 (file)
--- a/support/support.h
+++ b/support/support.h
@@ -113,7 +113,7 @@ void *xposix_memalign (size_t alignment, size_t n)
   __attribute_malloc__ __attribute_alloc_align__ ((1))
   __attribute_alloc_size__ ((2)) __attr_dealloc_free __returns_nonnull;
 char *xasprintf (const char *format, ...)
-  __attribute__ ((format (printf, 1, 2), malloc)) __attr_dealloc_free
+  __attribute__ ((format (printf, 1, 2), __malloc__)) __attr_dealloc_free
   __returns_nonnull;
 char *xstrdup (const char *) __attr_dealloc_free __returns_nonnull;
 char *xstrndup (const char *, size_t) __attr_dealloc_free __returns_nonnull;

diff --git a/test-skeleton.c b/test-skeleton.c
index efd52a6fa447ebce461105a0e92d2f7228ab589f..508522fa33198df115142489d82f6814821c7e70 100644 (file)
--- a/test-skeleton.c
+++ b/test-skeleton.c
@@ -27,7 +27,6 @@
 #include <errno.h>
 #include <fcntl.h>
 #include <getopt.h>
-#include <malloc.h>
 #include <paths.h>
 #include <search.h>
 #include <signal.h>