Hi,
I was working on making sure that allocations for [1] don't overflow
size_t for large hash tables, when created on 32bit systems. I started
to write code like
if (sizeof(SH_CONTAINS) * (uint64) tb->size) != sizeof(SH_CONTAINS) * (size_t) tb->size))
{ elog(ERROR, "hash table too large for a 32 bit system");
}
that could code potentially, although somewhat unlikely, be trigger on a
32bit system.
That made me wonder if it's not actually a mistake for
MemoryContextAllocExtended() size parameter to be declared
Size/size_t. That prevents it from detecting such overflows, forcing
code like the above on callsites.
Comments?
- Andres
[1] http://archives.postgresql.org/message-id/20160727004333.r3e2k2y6fvk2ntup%40alap3.anarazel.de
