The new exceptional EH allocator failed to align exception objects
properly (it ended up aligning to __alignof__((std::size_t))). The
following fixes that by aligning to what __attribute__((aligned))
would align to (this is what _Unwind_Exception is aligned to, a
member of __cxa_refcounted_exception).
Bootstrapped and tested on x86_64-unknown-linux-gnu - Rainer is
testing this on sparc-solaris where it broke
g++.old-deja/g++.eh/badalloc1.C.
Ok for trunk?
Thanks,
Richard.
2015-01-27 Richard Biener <rguent...@suse.de>
PR libstdc++/64798
* libsupc++/eh_alloc.cc (struct allocated_entry): Align
data member.
(pool::allocate): Adjust allocation size and alignment to
that change.
(pool::free): Adjust pointer offsetting.
Index: libstdc++-v3/libsupc++/eh_alloc.cc
===================================================================
--- libstdc++-v3/libsupc++/eh_alloc.cc (revision 220164)
+++ libstdc++-v3/libsupc++/eh_alloc.cc (working copy)
@@ -94,7 +94,7 @@ namespace
};
struct allocated_entry {
std::size_t size;
- char data[];
+ char data[] __attribute__((aligned));
};
// A single mutex controlling emergency allocations.
@@ -133,17 +133,18 @@ namespace
void *pool::allocate (std::size_t size)
{
__gnu_cxx::__scoped_lock sentry(emergency_mutex);
- // We need an additional size_t member.
- size += sizeof (std::size_t);
+ // We need an additional size_t member plus the padding to
+ // ensure proper alignment of data.
+ size += offsetof (allocated_entry, data);
// And we need to at least hand out objects of the size of
// a freelist entry.
if (size < sizeof (free_entry))
size = sizeof (free_entry);
- // And we need to align objects we hand out to the required
- // alignment of a freelist entry (this really aligns the
+ // And we need to align objects we hand out to the maximum
+ // alignment required on the target (this really aligns the
// tail which will become a new freelist entry).
- size = ((size + __alignof__(free_entry) - 1)
- & ~(__alignof__(free_entry) - 1));
+ size = ((size + __alignof__ (allocated_entry::data) - 1)
+ & ~(__alignof__ (allocated_entry::data) - 1));
// Search for an entry of proper size on the freelist.
free_entry **e;
for (e = &first_free_entry;
@@ -185,7 +186,7 @@ namespace
{
__gnu_cxx::__scoped_lock sentry(emergency_mutex);
allocated_entry *e = reinterpret_cast <allocated_entry *>
- (reinterpret_cast <char *> (data) - sizeof (std::size_t));
+ (reinterpret_cast <char *> (data) - offsetof (allocated_entry, data));
std::size_t sz = e->size;
if (!first_free_entry)
{
