Use get_call_result_type() more widely

Hi,

A review comment in another thread [1] by Michael Paquier about the
usage of get_call_result_type() instead of explicit building of
TupleDesc made me think about using it more widely. Actually, the
get_call_result_type() looks at the function definitions to figure the
column names and build the required TupleDesc, usage of which avoids
duplication of the column names between pg_proc.dat/function
definitions and source code. Also, it saves a good number of LOC ~415
[2] and the size of all the object files put together gets reduced by
~4MB, which means, the postgres binary becomes leaner by ~4MB [3]. I'm
attaching a patch for these changes.

While on this, I observed that BlessTupleDesc() is called in many
(~12) places right after get_call_result_type() which actually does
the job of BlessTupleDesc() before returning the TupleDesc. I think we
can get rid of BlessTupleDesc() after get_call_result_type(). I'm
attaching a patch for these changes too.

cirrus-ci members are happy with these patches, please see here
https://github.com/BRupireddy/postgres/tree/use_get_call_result_type()_more_widely_v1.

Thoughts?

[1] https://www.postgresql.org/message-id/Y41De5NnF2sxmJPI%40paquier.xyz

[2] 21 files changed, 97 insertions(+), 514 deletions(-)

[3] Source code is built with CFLAGS = -O3.
PATCHED:
text data bss dec hex filename
1043 0 0 1043 413 contrib/old_snapshot/time_mapping.o
7192 0 0 7192 1c18 contrib/pg_visibility/pg_visibility.o
7144 0 120 7264 1c60 src/backend/access/transam/commit_ts.o
19681 24 248 19953 4df1 src/backend/access/transam/multixact.o
20595 0 88 20683 50cb src/backend/access/transam/twophase.o
6162 0 24 6186 182a src/backend/access/transam/xlogfuncs.o
45540 2736 8 48284 bc9c src/backend/catalog/objectaddress.o
9943 0 0 9943 26d7 src/backend/catalog/pg_publication.o
18239 0 16 18255 474f src/backend/commands/sequence.o
6429 0 0 6429 191d src/backend/tsearch/wparser.o
47049 1840 52 48941 bf2d src/backend/utils/adt/acl.o
43066 168 784 44018 abf2 src/backend/utils/adt/datetime.o
6843 0 0 6843 1abb src/backend/utils/adt/genfile.o
6904 120 0 7024 1b70 src/backend/utils/adt/lockfuncs.o
10512 7008 0 17520 4470 src/backend/utils/adt/misc.o
1569 0 0 1569 621 src/backend/utils/adt/partitionfuncs.o
16266 0 0 16266 3f8a src/backend/utils/adt/pgstatfuncs.o
40985 0 0 40985 a019 src/backend/utils/adt/tsvector_op.o
8322 0 0 8322 2082 src/backend/utils/misc/guc_funcs.o
2109 0 0 2109 83d src/backend/utils/misc/pg_controldata.o
2354 0 0 2354 932
src/test/modules/test_predtest/test_predtest.o
9586047 226936 205536 10018519 98ded7 src/backend/postgres

HEAD:
text data bss dec hex filename
1019 0 0 1019 3fb contrib/old_snapshot/time_mapping.o
7159 0 0 7159 1bf7 contrib/pg_visibility/pg_visibility.o
6655 0 120 6775 1a77 src/backend/access/transam/commit_ts.o
19636 24 248 19908 4dc4 src/backend/access/transam/multixact.o
20663 0 88 20751 510f src/backend/access/transam/twophase.o
6206 0 24 6230 1856 src/backend/access/transam/xlogfuncs.o
45700 2736 8 48444 bd3c src/backend/catalog/objectaddress.o
9952 0 0 9952 26e0 src/backend/catalog/pg_publication.o
18487 0 16 18503 4847 src/backend/commands/sequence.o
6143 0 0 6143 17ff src/backend/tsearch/wparser.o
47123 1840 52 49015 bf77 src/backend/utils/adt/acl.o
43099 168 784 44051 ac13 src/backend/utils/adt/datetime.o
7016 0 0 7016 1b68 src/backend/utils/adt/genfile.o
7413 120 0 7533 1d6d src/backend/utils/adt/lockfuncs.o
10698 7008 0 17706 452a src/backend/utils/adt/misc.o
1593 0 0 1593 639 src/backend/utils/adt/partitionfuncs.o
17194 0 0 17194 432a src/backend/utils/adt/pgstatfuncs.o
40798 0 0 40798 9f5e src/backend/utils/adt/tsvector_op.o
8871 0 0 8871 22a7 src/backend/utils/misc/guc_funcs.o
3918 0 0 3918 f4e src/backend/utils/misc/pg_controldata.o
2636 0 0 2636 a4c
src/test/modules/test_predtest/test_predtest.o
9589943 226936 205536 10022415 98ee0f src/backend/postgres

--
Bharath Rupireddy
PostgreSQL Contributors Team
RDS Open Source Databases
Amazon Web Services: https://aws.amazon.com