On 16/09/16 09:04 +0200, Rainer Orth wrote:
Hi Jason,
OK, one more:
this works just fine on both sparc-sun-solaris2.12 and
i386-pc-solaris2.12.
Once Jonathan's patch to heed aligned_alloc's requirement on size being
a multiple of alignment is in, all is fine on Solaris.
I've got a slightly different fix now.
We only need to make the size a multiple of alignment for
aligned_alloc, however for posix_memalign we need to ensure the
alignment is a multiple of sizeof(void*).
I'm testing this now (but only on x86_64 GNU/Linux where it wasn't
failing anyway).
Would using __builtin_expect (sz == 0, false) make sense? Surely it's
rare to try to allocate zero bytes.
commit 216b9547230295e615bab86aaede65554f63e57d
Author: Jonathan Wakely <jwak...@redhat.com>
Date: Fri Sep 16 09:54:51 2016 +0100
Adjust arguments to aligned_alloc or posix_memalign
* libsupc++/new_opa.cc [_GLIBCXX_HAVE_POSIX_MEMALIGN] (aligned_alloc):
Increase alignment if less than sizeof(void*).
[_GLIBCXX_HAVE_ALIGNED_ALLOC] (operator new(size_t, align_val_t)):
Increase size if not a multiple of alignment.
diff --git a/libstdc++-v3/libsupc++/new_opa.cc b/libstdc++-v3/libsupc++/new_opa.cc
index 6ff5421..9c859c1 100644
--- a/libstdc++-v3/libsupc++/new_opa.cc
+++ b/libstdc++-v3/libsupc++/new_opa.cc
@@ -39,6 +39,9 @@ static inline void*
aligned_alloc (std::size_t al, std::size_t sz)
{
void *ptr;
+ // The value of alignment shall be a power of two multiple of sizeof(void *).
+ if (al < sizeof(void*))
+ al = sizeof(void*);
int ret = posix_memalign (&ptr, al, sz);
if (ret == 0)
return ptr;
@@ -58,13 +61,19 @@ _GLIBCXX_WEAK_DEFINITION void *
operator new (std::size_t sz, std::align_val_t al)
{
void *p;
+ std::size_t align = (std::size_t)al;
/* malloc (0) is unpredictable; avoid it. */
if (sz == 0)
sz = 1;
- while (__builtin_expect ((p = aligned_alloc ((std::size_t)al, sz)) == 0,
- false))
+#if _GLIBCXX_HAVE_ALIGNED_ALLOC
+ /* C11: the value of size shall be an integral multiple of alignment. */
+ if (std::size_t rem = sz % align)
+ sz += align - rem;
+#endif
+
+ while (__builtin_expect ((p = aligned_alloc (align, sz)) == 0, false))
{
new_handler handler = std::get_new_handler ();
if (! handler)
