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Tom Lane b853eb9718 Improve handling of ereport(ERROR) and elog(ERROR). 
In commit 71450d7fd6, we added code to inform
suitably-intelligent compilers that ereport() doesn't return if the elevel
is ERROR or higher.  This patch extends that to elog(), and also fixes a
double-evaluation hazard that the previous commit created in ereport(),
as well as reducing the emitted code size.

The elog() improvement requires the compiler to support __VA_ARGS__, which
should be available in just about anything nowadays since it's required by
C99.  But our minimum language baseline is still C89, so add a configure
test for that.

The previous commit assumed that ereport's elevel could be evaluated twice,
which isn't terribly safe --- there are already counterexamples in xlog.c.
On compilers that have __builtin_constant_p, we can use that to protect the
second test, since there's no possible optimization gain if the compiler
doesn't know the value of elevel.  Otherwise, use a local variable inside
the macros to prevent double evaluation.  The local-variable solution is
inferior because (a) it leads to useless code being emitted when elevel
isn't constant, and (b) it increases the optimization level needed for the
compiler to recognize that subsequent code is unreachable.  But it seems
better than not teaching non-gcc compilers about unreachability at all.

Lastly, if the compiler has __builtin_unreachable(), we can use that
instead of abort(), resulting in a noticeable code savings since no
function call is actually emitted.  However, it seems wise to do this only
in non-assert builds.  In an assert build, continue to use abort(), so that
the behavior will be predictable and debuggable if the "impossible"
happens.

These changes involve making the ereport and elog macros emit do-while
statement blocks not just expressions, which forces small changes in
a few call sites.

Andres Freund, Tom Lane, Heikki Linnakangas
2013-01-13 18:40:09 -05:00
..
adminpack Update copyrights for 2013 2013-01-01 17:15:01 -05:00
auth_delay Limit values of archive_timeout, post_auth_delay, auth_delay.milliseconds. 2012-11-18 17:15:06 -05:00
auto_explain Update copyrights for 2013 2013-01-01 17:15:01 -05:00
btree_gin
btree_gist
chkpass
citext
cube Improve handling of ereport(ERROR) and elog(ERROR). 2013-01-13 18:40:09 -05:00
dblink Update copyrights for 2013 2013-01-01 17:15:01 -05:00
dict_int Update copyrights for 2013 2013-01-01 17:15:01 -05:00
dict_xsyn Update copyrights for 2013 2013-01-01 17:15:01 -05:00
dummy_seclabel Update copyrights for 2013 2013-01-01 17:15:01 -05:00
earthdistance
file_fdw Update copyrights for 2013 2013-01-01 17:15:01 -05:00
fuzzystrmatch Update copyrights for 2013 2013-01-01 17:15:01 -05:00
hstore
intagg
intarray
isn Update copyrights for 2013 2013-01-01 17:15:01 -05:00
lo
ltree
oid2name
pageinspect Update copyrights for 2013 2013-01-01 17:15:01 -05:00
passwordcheck Update copyrights for 2013 2013-01-01 17:15:01 -05:00
pg_archivecleanup In our source code, make a copy of getopt's 'optarg' string arguments, 2012-10-12 13:35:43 -04:00
pg_buffercache
pg_freespacemap
pg_standby In our source code, make a copy of getopt's 'optarg' string arguments, 2012-10-12 13:35:43 -04:00
pg_stat_statements Update copyrights for 2013 2013-01-01 17:15:01 -05:00
pg_test_fsync Move long_options structures to the top of main() functions, for 2012-11-30 14:49:55 -05:00
pg_test_timing Move long_options structures to the top of main() functions, for 2012-11-30 14:49:55 -05:00
pg_trgm
pg_upgrade Extend and improve use of EXTRA_REGRESS_OPTS. 2013-01-12 08:28:58 -05:00
pg_upgrade_support Update copyrights for 2013 2013-01-01 17:15:01 -05:00
pgbench Add new "-q" logging option (quiet mode) while in initialize mode 2013-01-07 11:13:44 +09:00
pgcrypto
pgrowlocks
pgstattuple Add pgstatginindex() function to get the size of the GIN pending list. 2012-12-05 09:58:03 +02:00
seg Improve handling of ereport(ERROR) and elog(ERROR). 2013-01-13 18:40:09 -05:00
sepgsql Update copyrights for 2013 2013-01-01 17:15:01 -05:00
spi
sslinfo
start-scripts
tablefunc Update copyrights for 2013 2013-01-01 17:15:01 -05:00
tcn Update copyrights for 2013 2013-01-01 17:15:01 -05:00
test_parser Update copyrights for 2013 2013-01-01 17:15:01 -05:00
tsearch2 Update copyrights for 2013 2013-01-01 17:15:01 -05:00
unaccent Update copyrights for 2013 2013-01-01 17:15:01 -05:00
uuid-ossp Update copyrights for 2013 2013-01-01 17:15:01 -05:00
vacuumlo Update copyrights for 2013 2013-01-01 17:15:01 -05:00
worker_spi Background worker processes 2012-12-06 17:47:30 -03:00
xml2
contrib-global.mk
Makefile Background worker processes 2012-12-06 17:47:30 -03:00
README

README 

The PostgreSQL contrib tree
---------------------------

This subtree contains porting tools, analysis utilities, and plug-in
features that are not part of the core PostgreSQL system, mainly
because they address a limited audience or are too experimental to be
part of the main source tree.  This does not preclude their
usefulness.

User documentation for each module appears in the main SGML
documentation.

When building from the source distribution, these modules are not
built automatically, unless you build the "world" target.  You can
also build and install them all by running "gmake all" and "gmake
install" in this directory; or to build and install just one selected
module, do the same in that module's subdirectory.

Some directories supply new user-defined functions, operators, or
types.  To make use of one of these modules, after you have installed
the code you need to register the new SQL objects in the database
system by executing a CREATE EXTENSION command.  In a fresh database,
you can simply do

    CREATE EXTENSION module_name;

See the PostgreSQL documentation for more information about this
procedure.