On 23.01.26 18:33, Tom Lane wrote:
^
/home/debian/20-chimaera/buildroot/HEAD/pgsql.build/../pgsql/src/include/c.h:1132:49:
warning: requested alignment 4096 is larger than 128 [-Wattributes]
alignas(PG_IO_ALIGN_SIZE) char data[XLOG_BLCKSZ];
^
Not sure what to do about that, but I do read it as indicating that we
cannot put any faith in the compiler to honor such large alignment
demands.
A possible short-term(?) workaround is to wrap those two declarations
in "#ifndef __cplusplus", so that C++ code can't declare such
variables.
It looks like this was a bug in g++:
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=70066
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=89357
The suggestion there appears to be that it was fixed in gcc 9, but on
the buildfarm it only goes up to 6.
I think we could work around it like this:
#if defined(__cplusplus) && defined(__GNUC__) && __GNUC__ <= 6
#define alignas(a) __attribute__((aligned(a)))
#endif
