Tom Lane wrote:
> Alvaro Herrera <[email protected]> writes:
> > I wonder if this would be the right time to start using the
> > FLEXIBLE_ARRAY_MEMBER stuff in contrib/cube. Note pg_config.h.in says
>
> > /* Define to nothing if C supports flexible array members, and to 1 if it
> > does
> > not. That way, with a declaration like `struct s { int n; double
> > d[FLEXIBLE_ARRAY_MEMBER]; };', the struct hack can be used with pre-C99
> > compilers. When computing the size of such an object, don't use 'sizeof
> > (struct s)' as it overestimates the size. Use 'offsetof (struct s, d)'
> > instead. Don't use 'offsetof (struct s, d[0])', as this doesn't work with
> > MSVC and with C++ compilers. */
>
> D'oh ... I bet that last sentence is pointing us at the problem. cube
> is using exactly that construct, and for some reason it's crashing.
> The most likely explanation for why it's crashing is that the compiler
> is trying to dereference NULL instead of successfully reducing
> offsetof() to a compile-time constant. It's still not too clear to me
> why the inclusion changes cause that, but certainly walsender.h is
> pulling in a crapload of other stuff that was not previously included
> there ... which connects back to my previous complaints that I think
> Bruce was way too aggressive in adding #includes to headers.
>
> Jeremy, could you look at the preprocessor output for cube.c (ie,
> use -E instead of -c in the gcc call) and see how the relevant line
> of cube_f8_f8 looks in both broken and non-broken cases? What I see
> on a Fedora box is
>
> size = __builtin_offsetof (NDBOX, x[0]) +sizeof(double) * 2;
>
> but I'm thinking you might be getting something different.
I see 35 instances of this coding, and only 12 are in contrib/cube;
examples attached.
--
Bruce Momjian <[email protected]> http://momjian.us
EnterpriseDB http://enterprisedb.com
+ It's impossible for everything to be true. +
/usr/var/local/src/gen/pgsql/postgresql/contrib/cube/cubeparse.y:178: int size
= offsetof(NDBOX, x[0]) + sizeof(double) * dim * 2;
/usr/var/local/src/gen/pgsql/postgresql/contrib/cube/cubeparse.y:210: size =
offsetof(NDBOX, x[0]) + sizeof(double) * dim * 2;
/usr/var/local/src/gen/pgsql/postgresql/contrib/cube/cube.c:202: size =
offsetof(NDBOX, x[0]) +sizeof(double) * 2 * dim;
/usr/var/local/src/gen/pgsql/postgresql/contrib/cube/cube.c:238: size =
offsetof(NDBOX, x[0]) +sizeof(double) * 2 * dim;
/usr/var/local/src/gen/pgsql/postgresql/contrib/cube/cube.c:271: size =
offsetof(NDBOX, x[0]) +sizeof(double) * 2 * dim;
/usr/var/local/src/gen/pgsql/postgresql/contrib/cube/cube.c:1376: size =
offsetof(NDBOX, x[0]) +sizeof(double) * dim * 2;
/usr/var/local/src/gen/pgsql/postgresql/contrib/cube/cube.c:1417: size =
offsetof(NDBOX, x[0]) +sizeof(double) * 2;
/usr/var/local/src/gen/pgsql/postgresql/contrib/cube/cube.c:1435: size =
offsetof(NDBOX, x[0]) +sizeof(double) * 2;
/usr/var/local/src/gen/pgsql/postgresql/contrib/cube/cube.c:1456: size =
offsetof(NDBOX, x[0]) +sizeof(double) * (c->dim + 1) *2;
/usr/var/local/src/gen/pgsql/postgresql/contrib/cube/cube.c:1483: size =
offsetof(NDBOX, x[0]) +sizeof(double) * (c->dim + 1) *2;
/usr/var/local/src/gen/pgsql/postgresql/contrib/cube/cubeparse.c:1369: int
size = offsetof(NDBOX, x[0]) + sizeof(double) * dim * 2;
/usr/var/local/src/gen/pgsql/postgresql/contrib/cube/cubeparse.c:1401: size =
offsetof(NDBOX, x[0]) + sizeof(double) * dim * 2;
/usr/var/local/src/gen/pgsql/postgresql/src/backend/postmaster/pgstat.c:794:
len = offsetof(PgStat_MsgTabstat, m_entry[0]) +
/usr/var/local/src/gen/pgsql/postgresql/src/backend/postmaster/pgstat.c:840:
pgstat_send(&msg, offsetof(PgStat_MsgFuncstat, m_entry[0]) +
/usr/var/local/src/gen/pgsql/postgresql/src/backend/postmaster/pgstat.c:850:
pgstat_send(&msg, offsetof(PgStat_MsgFuncstat, m_entry[0]) +
/usr/var/local/src/gen/pgsql/postgresql/src/backend/postmaster/pgstat.c:951:
len = offsetof(PgStat_MsgTabpurge, m_tableid[0])
/usr/var/local/src/gen/pgsql/postgresql/src/backend/postmaster/pgstat.c:967:
len = offsetof(PgStat_MsgTabpurge, m_tableid[0])
/usr/var/local/src/gen/pgsql/postgresql/src/backend/postmaster/pgstat.c:1011:
len = offsetof(PgStat_MsgFuncpurge, m_functionid[0])
/usr/var/local/src/gen/pgsql/postgresql/src/backend/postmaster/pgstat.c:1025:
len = offsetof(PgStat_MsgFuncpurge, m_functionid[0])
/usr/var/local/src/gen/pgsql/postgresql/src/backend/postmaster/pgstat.c:1127:
len = offsetof(PgStat_MsgTabpurge, m_tableid[0]) +sizeof(Oid);
/usr/var/local/src/gen/pgsql/postgresql/src/backend/access/heap/syncscan.c:109:#define
SizeOfScanLocations(N) offsetof(ss_scan_locations_t, items[N])
/usr/var/local/src/gen/pgsql/postgresql/src/backend/access/nbtree/nbtree.c:535:
offsetof(BTScanPosData, items[1]) +
/usr/var/local/src/gen/pgsql/postgresql/src/backend/access/nbtree/nbtsearch.c:1120:
offsetof(BTScanPosData, items[1]) +
/usr/var/local/src/gen/pgsql/postgresql/src/backend/access/nbtree/nbtutils.c:1450:
size = offsetof(BTVacInfo, vacuums[0]);
/usr/var/local/src/gen/pgsql/postgresql/src/backend/utils/adt/geo_ops.c:1424:
size = offsetof(PATH, p[0]) +sizeof(path->p[0]) * npts;
/usr/var/local/src/gen/pgsql/postgresql/src/backend/utils/adt/geo_ops.c:1470:
if (npts <= 0 || npts >= (int32) ((INT_MAX - offsetof(PATH, p[0])) /
sizeof(Point)))
/usr/var/local/src/gen/pgsql/postgresql/src/backend/utils/adt/geo_ops.c:1475:
size = offsetof(PATH, p[0]) +sizeof(path->p[0]) * npts;
/usr/var/local/src/gen/pgsql/postgresql/src/backend/utils/adt/geo_ops.c:3476:
size = offsetof(POLYGON, p[0]) +sizeof(poly->p[0]) * npts;
/usr/var/local/src/gen/pgsql/postgresql/src/backend/utils/adt/geo_ops.c:3523:
if (npts <= 0 || npts >= (int32) ((INT_MAX - offsetof(POLYGON, p[0])) /
sizeof(Point)))
/usr/var/local/src/gen/pgsql/postgresql/src/backend/utils/adt/geo_ops.c:3528:
size = offsetof(POLYGON, p[0]) +sizeof(poly->p[0]) * npts;
/usr/var/local/src/gen/pgsql/postgresql/src/backend/utils/adt/geo_ops.c:4244:
size = offsetof(PATH, p[0]) +base_size;
/usr/var/local/src/gen/pgsql/postgresql/src/backend/utils/adt/geo_ops.c:4382:
size = offsetof(POLYGON, p[0]) +sizeof(poly->p[0]) * path->npts;
/usr/var/local/src/gen/pgsql/postgresql/src/backend/utils/adt/geo_ops.c:4457:
size = offsetof(POLYGON, p[0]) +sizeof(poly->p[0]) * 4;
/usr/var/local/src/gen/pgsql/postgresql/src/backend/utils/adt/geo_ops.c:4487:
size = offsetof(PATH, p[0]) +sizeof(path->p[0]) * poly->npts;
/usr/var/local/src/gen/pgsql/postgresql/src/backend/utils/adt/geo_ops.c:5166:
size = offsetof(POLYGON, p[0]) +base_size;
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