Re: valgrind error in tsvectorin - Mailing list pgsql-hackers

From Tom Lane
Subject Re: valgrind error in tsvectorin
Date
Msg-id 2572.1242340060@sss.pgh.pa.us
Whole thread Raw
In response to valgrind error in tsvectorin  (Gregory Stark <stark@enterprisedb.com>)
Responses Re: valgrind error in tsvectorin  (Greg Stark <stark@enterprisedb.com>)
List pgsql-hackers
Gregory Stark <stark@enterprisedb.com> writes:
> Was just running the regression tests under valgrind and aside from the usual
> false positives caused by structure padding I noticed this:

> ==19366== Source and destination overlap in memcpy(0x4BB7FC0, 0x4BB7FC0, 12)
> ==19366==    at 0x4026B12: memcpy (mc_replace_strmem.c:402)
> ==19366==    by 0x8389750: uniqueentry (tsvector.c:128)
> ==19366==    by 0x8389C63: tsvectorin (tsvector.c:265)
> ==19366==    by 0x83B1888: InputFunctionCall (fmgr.c:1878)
> ==19366==    by 0x83B1B46: OidInputFunctionCall (fmgr.c:2009)
> ==19366==    by 0x8171651: stringTypeDatum (parse_type.c:497)
> ==19366==    by 0x8171CAC: coerce_type (parse_coerce.c:239)
> ==19366==    by 0x8171A72: coerce_to_target_type (parse_coerce.c:86)
> ==19366==    by 0x8166DB5: transformTypeCast (parse_expr.c:2016)
> ==19366==    by 0x8162FA8: transformExpr (parse_expr.c:181)
> ==19366==    by 0x8174990: transformTargetEntry (parse_target.c:75)
> ==19366==    by 0x8174B01: transformTargetList (parse_target.c:145)

> After a quick glance at the code I suspect res and ptr end up pointing to the
> same object, perhaps the loop condition has a fencepost error. But I don't
> really understand what it's trying to do at all.

Yeah, it looks like the memcpy is sometimes unnecessary because res and
ptr point to the same place.  It might be worth cleaning up just to
avoid the valgrind warning, but I doubt it would save any noticeable
number of cycles.
        regards, tom lane


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