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[4/9] Sync scratch_buffer with gnulib

Message ID 1504643122-14874-5-git-send-email-adhemerval.zanella@linaro.org
State Dropped
Headers

Commit Message

Adhemerval Zanella Sept. 5, 2017, 8:25 p.m. UTC 
  This patch syncs the scratch_buffer grom gnulib commit 3866ef6 with
GLIBC code.

Checked on x86_64-linux-gnu and on a build using build-many-glibcs.py
for all major architectures.

	* include/scratch_buffer.h (scratch_buffer): Use a C99 align method
	instead of GCC extension.
	* malloc/scratch_buffer_grow.c [!_LIBC]: Include libc-config.h.
	* malloc/scratch_buffer_grow_preserve.c [!_LIBC]: Likewise.
	* malloc/scratch_buffer_set_array_size.c [!_LIBC]: Likewise.
---
 ChangeLog                              | 6 ++++++
 include/scratch_buffer.h               | 3 +--
 malloc/scratch_buffer_grow.c           | 6 +++++-
 malloc/scratch_buffer_grow_preserve.c  | 6 +++++-
 malloc/scratch_buffer_set_array_size.c | 6 +++++-
 5 files changed, 22 insertions(+), 5 deletions(-)

Comments

Florian Weimer Sept. 18, 2017, 6:09 a.m. UTC | #1 
On 09/05/2017 10:25 PM, Adhemerval Zanella wrote:
> -  char __space[1024]
> -    __attribute__ ((aligned (__alignof__ (max_align_t))));
> +  max_align_t __space[(1023 + sizeof (max_align_t)) / sizeof (max_align_t)];

This change needs a declaration from the GCC folks (probably from 
Richard Biener) that it does not break aliasing analysis.  The old code 
uses a GCC extension (writing to a char array changes its dynamic type); 
it is not valid C.  I don't know if the GCC extension also applies if 
the storage site is declared with a non-char type.

Thanks,
Florian
diff mbox

Patch

diff --git a/include/scratch_buffer.h b/include/scratch_buffer.h
index dd17a4a..bb04662 100644
--- a/include/scratch_buffer.h
+++ b/include/scratch_buffer.h
@@ -66,8 +66,7 @@ 
 struct scratch_buffer {
   void *data;    /* Pointer to the beginning of the scratch area.  */
   size_t length; /* Allocated space at the data pointer, in bytes.  */
-  char __space[1024]
-    __attribute__ ((aligned (__alignof__ (max_align_t))));
+  max_align_t __space[(1023 + sizeof (max_align_t)) / sizeof (max_align_t)];
 };
 
 /* Initializes *BUFFER so that BUFFER->data points to BUFFER->__space
diff --git a/malloc/scratch_buffer_grow.c b/malloc/scratch_buffer_grow.c
index 22bae50..d2df028 100644
--- a/malloc/scratch_buffer_grow.c
+++ b/malloc/scratch_buffer_grow.c
@@ -16,6 +16,10 @@ 
    License along with the GNU C Library; if not, see
    <http://www.gnu.org/licenses/>.  */
 
+#ifndef _LIBC
+# include <libc-config.h>
+#endif
+
 #include <scratch_buffer.h>
 #include <errno.h>
 
@@ -49,4 +53,4 @@  __libc_scratch_buffer_grow (struct scratch_buffer *buffer)
   buffer->length = new_length;
   return true;
 }
-libc_hidden_def (__libc_scratch_buffer_grow);
+libc_hidden_def (__libc_scratch_buffer_grow)
diff --git a/malloc/scratch_buffer_grow_preserve.c b/malloc/scratch_buffer_grow_preserve.c
index 18543ef..9268615 100644
--- a/malloc/scratch_buffer_grow_preserve.c
+++ b/malloc/scratch_buffer_grow_preserve.c
@@ -16,6 +16,10 @@ 
    License along with the GNU C Library; if not, see
    <http://www.gnu.org/licenses/>.  */
 
+#ifndef _LIBC
+# include <libc-config.h>
+#endif
+
 #include <scratch_buffer.h>
 #include <errno.h>
 #include <string.h>
@@ -60,4 +64,4 @@  __libc_scratch_buffer_grow_preserve (struct scratch_buffer *buffer)
   buffer->length = new_length;
   return true;
 }
-libc_hidden_def (__libc_scratch_buffer_grow_preserve);
+libc_hidden_def (__libc_scratch_buffer_grow_preserve)
diff --git a/malloc/scratch_buffer_set_array_size.c b/malloc/scratch_buffer_set_array_size.c
index 8ab6d9d..6fcc115 100644
--- a/malloc/scratch_buffer_set_array_size.c
+++ b/malloc/scratch_buffer_set_array_size.c
@@ -16,6 +16,10 @@ 
    License along with the GNU C Library; if not, see
    <http://www.gnu.org/licenses/>.  */
 
+#ifndef _LIBC
+# include <libc-config.h>
+#endif
+
 #include <scratch_buffer.h>
 #include <errno.h>
 #include <limits.h>
@@ -57,4 +61,4 @@  __libc_scratch_buffer_set_array_size (struct scratch_buffer *buffer,
   buffer->length = new_length;
   return true;
 }
-libc_hidden_def (__libc_scratch_buffer_set_array_size);
+libc_hidden_def (__libc_scratch_buffer_set_array_size)