* [PATCH v3] xmalloc: Fix warnings with gcc analyzer
@ 2021-07-28 11:32 Siddhesh Poyarekar
2021-07-28 12:04 ` Florian Weimer
0 siblings, 1 reply; 2+ messages in thread
From: Siddhesh Poyarekar @ 2021-07-28 11:32 UTC (permalink / raw)
To: libc-alpha; +Cc: fweimer
Tell the compiler that xmalloc family of allocators always return
non-NULL. xrealloc in locale/programs also always returns non-NULL,
but that conflicts with default realloc behaviour and that of xrealloc
in libsupport, so keep it as is for now and resolve the differences
later.
---
include/programs/xmalloc.h | 9 ++++++---
misc/sys/cdefs.h | 10 ++++++++++
2 files changed, 16 insertions(+), 3 deletions(-)
diff --git a/include/programs/xmalloc.h b/include/programs/xmalloc.h
index 33871e22ef..5dc6aac57b 100644
--- a/include/programs/xmalloc.h
+++ b/include/programs/xmalloc.h
@@ -23,11 +23,14 @@
/* Prototypes for a few program-wide used functions. */
extern void *xmalloc (size_t n)
- __attribute_malloc__ __attribute_alloc_size__ ((1)) __attr_dealloc_free;
+ __attribute_malloc__ __attribute_alloc_size__ ((1)) __attr_dealloc_free
+ __returns_nonnull;
extern void *xcalloc (size_t n, size_t s)
- __attribute_malloc__ __attribute_alloc_size__ ((1, 2)) __attr_dealloc_free;
+ __attribute_malloc__ __attribute_alloc_size__ ((1, 2)) __attr_dealloc_free
+ __returns_nonnull;
extern void *xrealloc (void *o, size_t n)
__attribute_malloc__ __attribute_alloc_size__ ((2)) __attr_dealloc_free;
-extern char *xstrdup (const char *) __attribute_malloc__ __attr_dealloc_free;
+extern char *xstrdup (const char *) __attribute_malloc__ __attr_dealloc_free
+ __returns_nonnull;
#endif /* xmalloc.h */
diff --git a/misc/sys/cdefs.h b/misc/sys/cdefs.h
index 30a621ab8f..e490fc1aeb 100644
--- a/misc/sys/cdefs.h
+++ b/misc/sys/cdefs.h
@@ -330,6 +330,16 @@
# define __nonnull(params) _GL_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__)
--
2.31.1
^ permalink raw reply [flat|nested] 2+ messages in thread
* Re: [PATCH v3] xmalloc: Fix warnings with gcc analyzer
2021-07-28 11:32 [PATCH v3] xmalloc: Fix warnings with gcc analyzer Siddhesh Poyarekar
@ 2021-07-28 12:04 ` Florian Weimer
0 siblings, 0 replies; 2+ messages in thread
From: Florian Weimer @ 2021-07-28 12:04 UTC (permalink / raw)
To: Siddhesh Poyarekar; +Cc: libc-alpha
* Siddhesh Poyarekar:
> Tell the compiler that xmalloc family of allocators always return
> non-NULL. xrealloc in locale/programs also always returns non-NULL,
> but that conflicts with default realloc behaviour and that of xrealloc
> in libsupport, so keep it as is for now and resolve the differences
> later.
> ---
> include/programs/xmalloc.h | 9 ++++++---
> misc/sys/cdefs.h | 10 ++++++++++
> 2 files changed, 16 insertions(+), 3 deletions(-)
>
> diff --git a/include/programs/xmalloc.h b/include/programs/xmalloc.h
> index 33871e22ef..5dc6aac57b 100644
> --- a/include/programs/xmalloc.h
> +++ b/include/programs/xmalloc.h
> @@ -23,11 +23,14 @@
>
> /* Prototypes for a few program-wide used functions. */
> extern void *xmalloc (size_t n)
> - __attribute_malloc__ __attribute_alloc_size__ ((1)) __attr_dealloc_free;
> + __attribute_malloc__ __attribute_alloc_size__ ((1)) __attr_dealloc_free
> + __returns_nonnull;
> extern void *xcalloc (size_t n, size_t s)
> - __attribute_malloc__ __attribute_alloc_size__ ((1, 2)) __attr_dealloc_free;
> + __attribute_malloc__ __attribute_alloc_size__ ((1, 2)) __attr_dealloc_free
> + __returns_nonnull;
> extern void *xrealloc (void *o, size_t n)
> __attribute_malloc__ __attribute_alloc_size__ ((2)) __attr_dealloc_free;
> -extern char *xstrdup (const char *) __attribute_malloc__ __attr_dealloc_free;
> +extern char *xstrdup (const char *) __attribute_malloc__ __attr_dealloc_free
> + __returns_nonnull;
>
> #endif /* xmalloc.h */
> diff --git a/misc/sys/cdefs.h b/misc/sys/cdefs.h
> index 30a621ab8f..e490fc1aeb 100644
> --- a/misc/sys/cdefs.h
> +++ b/misc/sys/cdefs.h
> @@ -330,6 +330,16 @@
> # define __nonnull(params) _GL_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__)
I think this version is okay, thanks.
Florian
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2021-07-28 12:04 ` Florian Weimer
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