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[committed] parisc: Define MALLOC_ABI_ALIGNMENT

Message ID 40962D89-2B16-4953-A171-8D6821058478@bell.net
State New
Headers show

Commit Message

John David Anglin Oct. 9, 2016, 5:08 p.m. UTC 
The attached patch defines MALLOC_ABI_ALIGNMENT so that it now reflects the alignment
provided by malloc on hpux and linux.

I also adjusted the comment for BIGGEST_ALIGNMENT so that the define is more understandable.

Tested on hppa2.0w-hp-hpux11.11, hppa64-hp-hpux11.11 and hppa-unknown-linux-gnu.

Committed to trunk.

Dave
--
John David Anglin	dave.anglin@bell.net
2016-10-09  John David Anglin  <danglin@gcc.gnu.org>

	* config/pa/pa.h (BIGGEST_ALIGNMENT): Adjust comment.
	(MALLOC_ABI_ALIGNMENT): Define.
diff mbox

Patch

Index: config/pa/pa.h
===================================================================
--- config/pa/pa.h	(revision 240688)
+++ config/pa/pa.h	(working copy)
@@ -292,9 +292,21 @@ 
 /* A bit-field declared as `int' forces `int' alignment for the struct.  */
 #define PCC_BITFIELD_TYPE_MATTERS 1
 
-/* No data type wants to be aligned rounder than this.  */
+/* No data type wants to be aligned rounder than this.  The long double
+   type has 16-byte alignment on the 64-bit target even though it was never
+   implemented in hardware.  The software implementation only needs 8-byte
+   alignment.  This is to match the HP compilers.  */
 #define BIGGEST_ALIGNMENT (2 * BITS_PER_WORD)
 
+/* Alignment, in bits, a C conformant malloc implementation has to provide.
+   The HP-UX malloc implementation provides a default alignment of 8 bytes.
+   This can be increased with mallopt.  The glibc implementation also provides
+   8-byte alignment.  Note that this isn't enough for various POSIX types such
+   as pthread_mutex_t.  However, since we no longer need the 16-byte alignment
+   for atomic operations, we ignore the nominal alignment specified for these
+   types.  The same is true for long double on 64-bit HP-UX.  */
+#define MALLOC_ABI_ALIGNMENT (64)
+
 /* Get around hp-ux assembler bug, and make strcpy of constants fast.  */
 #define CONSTANT_ALIGNMENT(EXP, ALIGN)		\
   (TREE_CODE (EXP) == STRING_CST		\