diff mbox series

[v2] malloc: add indirection for malloc(-like) functions in tests [BZ #32366]

Message ID 34c1524f646e64b310a260ed536c2e63c5c3fa53.1733791871.git.sam@gentoo.org
State New
Headers show
Series [v2] malloc: add indirection for malloc(-like) functions in tests [BZ #32366] | expand

Commit Message

Sam James Dec. 10, 2024, 12:51 a.m. UTC
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 TEST_MALLOC (and friends) wrappers with a volatile
function pointer to obscure that we're calling malloc (et. al) from the
compiler.
---
There are some more functions we should perhaps cover like reallocarray
just to futureproof, but I was minded to do that separately to get this
fix in and unblock regression testers against GCC trunk.

v2: Switch to undef-based approach as suggested by Paul Eggert.

 malloc/tst-aligned-alloc.c    |  2 ++
 malloc/tst-compathooks-off.c  |  2 ++
 malloc/tst-malloc-aux.h       | 41 +++++++++++++++++++++++++++++++++++
 malloc/tst-malloc-check.c     |  2 ++
 malloc/tst-malloc-too-large.c |  1 +
 malloc/tst-malloc.c           |  2 ++
 malloc/tst-realloc.c          |  2 ++
 support/support.h             |  2 +-
 test-skeleton.c               |  1 -
 9 files changed, 53 insertions(+), 2 deletions(-)
 create mode 100644 malloc/tst-malloc-aux.h

Comments

Paul Eggert Dec. 10, 2024, 1:46 a.m. UTC | #1
On 2024-12-09 16:51, Sam James wrote:
> Handle this by providing TEST_MALLOC (and friends) wrappers with a volatile

TEST_MALLOC -> malloc

Otherwise, it looks good to me. Thanks.

Reviewed-by: Paul Eggert <eggert@cs.ucla.edu>
Sam James Dec. 10, 2024, 1:55 a.m. UTC | #2
Paul Eggert <eggert@cs.ucla.edu> writes:

> On 2024-12-09 16:51, Sam James wrote:
>> Handle this by providing TEST_MALLOC (and friends) wrappers with a volatile
>
> TEST_MALLOC -> malloc
>
> Otherwise, it looks good to me. Thanks.
>
> Reviewed-by: Paul Eggert <eggert@cs.ucla.edu>

Thanks, fixed and pushed.
diff mbox series

Patch

diff --git a/malloc/tst-aligned-alloc.c b/malloc/tst-aligned-alloc.c
index 91167d1392..b0f05a8fec 100644
--- 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 d0106f3fb7..4cce6e5a80 100644
--- 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
index 0000000000..54908b4a24
--- /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 fde8863ad7..cc88bff3b3 100644
--- 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 8e9e0d5fa2..2b91377e54 100644
--- 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 f7a6e4654c..68af399022 100644
--- a/malloc/tst-malloc.c
+++ b/malloc/tst-malloc.c
@@ -22,6 +22,8 @@ 
 #include <libc-diag.h>
 #include <time.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 f50499ecb1..74a28fb45e 100644
--- 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 ba21ec9b5a..1a77f79793 100644
--- 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 ae185a4f28..690f26e7cf 100644
--- 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>