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Remove unnecessary type violation in tsvectorrecv().

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compareentry() is declared to work on WordEntryIN structs, but
tsvectorrecv() is using it in two places to work on WordEntry
structs.  This is almost okay, since WordEntry is the first
field of WordEntryIN.  But on machines with 8-byte pointers,
WordEntryIN will have a larger alignment spec than WordEntry,
and it's at least theoretically possible that the compiler
could generate code that depends on the larger alignment.

Given the lack of field reports, this may be just a hypothetical bug
that upsets nothing except sanitizer tools.  Or it may be real on
certain hardware but nobody's tried to use tsvectorrecv() on such
hardware.  In any case we should fix it, and the fix is trivial:
just change compareentry() so that it works on WordEntry without any
mention of WordEntryIN.  We can also get rid of the quite-useless
intermediate function WordEntryCMP.

Bug: #18875
Reported-by: Alexander Lakhin <exclusion@gmail.com>
Author: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/18875-07a29c49c825a608@postgresql.org
Backpatch-through: 13
This commit is contained in:
Tom Lane
2025-04-02 16:17:43 -04:00
parent 77d90d6d63
commit d8aa826207
1 changed files with 10 additions and 13 deletions
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23
src/backend/utils/adt/tsvector.c
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@ -22,7 +22,7 @@
typedef struct typedef struct
{ {
WordEntry entry; /* must be first! */ WordEntry entry; /* must be first, see compareentry */
WordEntryPos *pos; WordEntryPos *pos;
int poslen; /* number of elements in pos */ int poslen; /* number of elements in pos */
} WordEntryIN; } WordEntryIN;
@ -78,16 +78,19 @@ uniquePos(WordEntryPos *a, int l)
return res + 1 - a; return res + 1 - a;
} }
/* Compare two WordEntryIN values for qsort */ /*
* Compare two WordEntry structs for qsort_arg. This can also be used on
* WordEntryIN structs, since those have WordEntry as their first field.
*/
static int static int
compareentry(const void *va, const void *vb, void *arg) compareentry(const void *va, const void *vb, void *arg)
{ {
const WordEntryIN *a = (const WordEntryIN *) va; const WordEntry *a = (const WordEntry *) va;
const WordEntryIN *b = (const WordEntryIN *) vb; const WordEntry *b = (const WordEntry *) vb;
char *BufferStr = (char *) arg; char *BufferStr = (char *) arg;
return tsCompareString(&BufferStr[a->entry.pos], a->entry.len, return tsCompareString(&BufferStr[a->pos], a->len,
&BufferStr[b->entry.pos], b->entry.len, &BufferStr[b->pos], b->len,
false); false);
} }
@ -167,12 +170,6 @@ uniqueentry(WordEntryIN *a, int l, char *buf, int *outbuflen)
return res + 1 - a; return res + 1 - a;
} }
static int
WordEntryCMP(WordEntry *a, WordEntry *b, char *buf)
{
return compareentry(a, b, buf);
}
Datum Datum
tsvectorin(PG_FUNCTION_ARGS) tsvectorin(PG_FUNCTION_ARGS)
@ -505,7 +502,7 @@ tsvectorrecv(PG_FUNCTION_ARGS)
datalen += lex_len; datalen += lex_len;
if (i > 0 && WordEntryCMP(&vec->entries[i], if (i > 0 && compareentry(&vec->entries[i],
&vec->entries[i - 1], &vec->entries[i - 1],
STRPTR(vec)) <= 0) STRPTR(vec)) <= 0)
needSort = true; needSort = true;