0001-REALLOCATE_BITMAPSETS-manual-compile-time-option-v1.patch

From 5a18e880fb53ee5b5a0be092b1cb796636dbb60c Mon Sep 17 00:00:00 2001
From: Alexander Korotkov <akorotkov@postgresql.org>
Date: Sun, 19 Nov 2023 01:03:12 +0200
Subject: [PATCH 1/2] REALLOCATE_BITMAPSETS manual compile-time option

This option forces each bitmapset modification to reallocate bitmapset.  This
is useful for debugging hangling pointers to bitmapset's.

Discussion: https://postgr.es/m/CAMbWs4_wJthNtYBL+SsebpgF-5L2r5zFFk6xYbS0A78GKOTFHw@mail.gmail.com
---
 src/backend/nodes/bitmapset.c  | 146 +++++++++++++++++++++++++++++----
 src/include/pg_config_manual.h |   6 ++
 2 files changed, 138 insertions(+), 14 deletions(-)

diff --git a/src/backend/nodes/bitmapset.c b/src/backend/nodes/bitmapset.c
index 704879f5660..8be3e3e2c5e 100644
--- a/src/backend/nodes/bitmapset.c
+++ b/src/backend/nodes/bitmapset.c
@@ -84,6 +84,7 @@ bms_copy(const Bitmapset *a)
 
 	if (a == NULL)
 		return NULL;
+	Assert(IsA(a, Bitmapset));
 	size = BITMAPSET_SIZE(a->nwords);
 	result = (Bitmapset *) palloc(size);
 	memcpy(result, a, size);
@@ -98,8 +99,8 @@ bms_equal(const Bitmapset *a, const Bitmapset *b)
 {
 	int			i;
 
-	Assert(a == NULL || a->words[a->nwords - 1] != 0);
-	Assert(b == NULL || b->words[b->nwords - 1] != 0);
+	Assert(a == NULL || (IsA(a, Bitmapset) && a->words[a->nwords - 1] != 0));
+	Assert(b == NULL || (IsA(b, Bitmapset) && b->words[b->nwords - 1] != 0));
 
 	/* Handle cases where either input is NULL */
 	if (a == NULL)
@@ -139,8 +140,8 @@ bms_compare(const Bitmapset *a, const Bitmapset *b)
 {
 	int			i;
 
-	Assert(a == NULL || a->words[a->nwords - 1] != 0);
-	Assert(b == NULL || b->words[b->nwords - 1] != 0);
+	Assert(a == NULL || (IsA(a, Bitmapset) && a->words[a->nwords - 1] != 0));
+	Assert(b == NULL || (IsA(b, Bitmapset) && b->words[b->nwords - 1] != 0));
 
 	/* Handle cases where either input is NULL */
 	if (a == NULL)
@@ -215,6 +216,9 @@ bms_union(const Bitmapset *a, const Bitmapset *b)
 	int			otherlen;
 	int			i;
 
+	Assert(a == NULL || IsA(a, Bitmapset));
+	Assert(b == NULL || IsA(b, Bitmapset));
+
 	/* Handle cases where either input is NULL */
 	if (a == NULL)
 		return bms_copy(b);
@@ -253,9 +257,13 @@ bms_intersect(const Bitmapset *a, const Bitmapset *b)
 	int			resultlen;
 	int			i;
 
+	Assert(a == NULL || IsA(a, Bitmapset));
+	Assert(b == NULL || IsA(b, Bitmapset));
+
 	/* Handle cases where either input is NULL */
 	if (a == NULL || b == NULL)
 		return NULL;
+
 	/* Identify shorter and longer input; copy the shorter one */
 	if (a->nwords <= b->nwords)
 	{
@@ -299,8 +307,8 @@ bms_difference(const Bitmapset *a, const Bitmapset *b)
 	Bitmapset  *result;
 	int			i;
 
-	Assert(a == NULL || a->words[a->nwords - 1] != 0);
-	Assert(b == NULL || b->words[b->nwords - 1] != 0);
+	Assert(a == NULL || (IsA(a, Bitmapset) && a->words[a->nwords - 1] != 0));
+	Assert(b == NULL || (IsA(b, Bitmapset) && b->words[b->nwords - 1] != 0));
 
 	/* Handle cases where either input is NULL */
 	if (a == NULL)
@@ -308,6 +316,8 @@ bms_difference(const Bitmapset *a, const Bitmapset *b)
 	if (b == NULL)
 		return bms_copy(a);
 
+	Assert(IsA(a, Bitmapset) && IsA(b, Bitmapset));
+
 	/*
 	 * In Postgres' usage, an empty result is a very common case, so it's
 	 * worth optimizing for that by testing bms_nonempty_difference().  This
@@ -364,8 +374,8 @@ bms_is_subset(const Bitmapset *a, const Bitmapset *b)
 {
 	int			i;
 
-	Assert(a == NULL || a->words[a->nwords - 1] != 0);
-	Assert(b == NULL || b->words[b->nwords - 1] != 0);
+	Assert(a == NULL || (IsA(a, Bitmapset) && a->words[a->nwords - 1] != 0));
+	Assert(b == NULL || (IsA(b, Bitmapset) && b->words[b->nwords - 1] != 0));
 
 	/* Handle cases where either input is NULL */
 	if (a == NULL)
@@ -373,6 +383,8 @@ bms_is_subset(const Bitmapset *a, const Bitmapset *b)
 	if (b == NULL)
 		return false;
 
+	Assert(IsA(a, Bitmapset) && IsA(b, Bitmapset));
+
 	/* 'a' can't be a subset of 'b' if it contains more words */
 	if (a->nwords > b->nwords)
 		return false;
@@ -399,8 +411,8 @@ bms_subset_compare(const Bitmapset *a, const Bitmapset *b)
 	int			shortlen;
 	int			i;
 
-	Assert(a == NULL || a->words[a->nwords - 1] != 0);
-	Assert(b == NULL || b->words[b->nwords - 1] != 0);
+	Assert(a == NULL || (IsA(a, Bitmapset) && a->words[a->nwords - 1] != 0));
+	Assert(b == NULL || (IsA(b, Bitmapset) && b->words[b->nwords - 1] != 0));
 
 	/* Handle cases where either input is NULL */
 	if (a == NULL)
@@ -411,6 +423,9 @@ bms_subset_compare(const Bitmapset *a, const Bitmapset *b)
 	}
 	if (b == NULL)
 		return BMS_SUBSET2;
+
+	Assert(IsA(a, Bitmapset) && IsA(b, Bitmapset));
+
 	/* Check common words */
 	result = BMS_EQUAL;			/* status so far */
 	shortlen = Min(a->nwords, b->nwords);
@@ -467,6 +482,9 @@ bms_is_member(int x, const Bitmapset *a)
 		elog(ERROR, "negative bitmapset member not allowed");
 	if (a == NULL)
 		return false;
+
+	Assert(IsA(a, Bitmapset));
+
 	wordnum = WORDNUM(x);
 	bitnum = BITNUM(x);
 	if (wordnum >= a->nwords)
@@ -495,6 +513,8 @@ bms_member_index(Bitmapset *a, int x)
 	if (!bms_is_member(x, a))
 		return -1;
 
+	Assert(IsA(a, Bitmapset));
+
 	wordnum = WORDNUM(x);
 	bitnum = BITNUM(x);
 
@@ -529,6 +549,9 @@ bms_overlap(const Bitmapset *a, const Bitmapset *b)
 	int			shortlen;
 	int			i;
 
+	Assert(a == NULL || IsA(a, Bitmapset));
+	Assert(b == NULL || IsA(b, Bitmapset));
+
 	/* Handle cases where either input is NULL */
 	if (a == NULL || b == NULL)
 		return false;
@@ -553,6 +576,8 @@ bms_overlap_list(const Bitmapset *a, const List *b)
 	int			wordnum,
 				bitnum;
 
+	Assert(a == NULL || IsA(a, Bitmapset));
+
 	if (a == NULL || b == NIL)
 		return false;
 
@@ -582,8 +607,8 @@ bms_nonempty_difference(const Bitmapset *a, const Bitmapset *b)
 {
 	int			i;
 
-	Assert(a == NULL || a->words[a->nwords - 1] != 0);
-	Assert(b == NULL || b->words[b->nwords - 1] != 0);
+	Assert(a == NULL || (IsA(a, Bitmapset) && a->words[a->nwords - 1] != 0));
+	Assert(b == NULL || (IsA(b, Bitmapset) && b->words[b->nwords - 1] != 0));
 
 	/* Handle cases where either input is NULL */
 	if (a == NULL)
@@ -617,6 +642,9 @@ bms_singleton_member(const Bitmapset *a)
 
 	if (a == NULL)
 		elog(ERROR, "bitmapset is empty");
+
+	Assert(IsA(a, Bitmapset));
+
 	nwords = a->nwords;
 	wordnum = 0;
 	do
@@ -657,6 +685,7 @@ bms_get_singleton_member(const Bitmapset *a, int *member)
 
 	if (a == NULL)
 		return false;
+	Assert(IsA(a, Bitmapset));
 	nwords = a->nwords;
 	wordnum = 0;
 	do
@@ -690,6 +719,7 @@ bms_num_members(const Bitmapset *a)
 
 	if (a == NULL)
 		return 0;
+	Assert(IsA(a, Bitmapset));
 	nwords = a->nwords;
 	wordnum = 0;
 	do
@@ -717,6 +747,7 @@ bms_membership(const Bitmapset *a)
 
 	if (a == NULL)
 		return BMS_EMPTY_SET;
+	Assert(IsA(a, Bitmapset));
 	nwords = a->nwords;
 	wordnum = 0;
 	do
@@ -759,6 +790,7 @@ bms_add_member(Bitmapset *a, int x)
 		elog(ERROR, "negative bitmapset member not allowed");
 	if (a == NULL)
 		return bms_make_singleton(x);
+	Assert(IsA(a, Bitmapset));
 	wordnum = WORDNUM(x);
 	bitnum = BITNUM(x);
 
@@ -767,8 +799,15 @@ bms_add_member(Bitmapset *a, int x)
 	{
 		int			oldnwords = a->nwords;
 		int			i;
+#ifdef REALLOCATE_BITMAPSETS
+		Bitmapset  *tmp = a;
 
+		a = (Bitmapset *) palloc(BITMAPSET_SIZE(wordnum + 1));
+		memcpy(a, tmp, BITMAPSET_SIZE(tmp->nwords));
+		pfree(tmp);
+#else
 		a = (Bitmapset *) repalloc(a, BITMAPSET_SIZE(wordnum + 1));
+#endif
 		a->nwords = wordnum + 1;
 		/* zero out the enlarged portion */
 		i = oldnwords;
@@ -777,6 +816,16 @@ bms_add_member(Bitmapset *a, int x)
 			a->words[i] = 0;
 		} while (++i < a->nwords);
 	}
+#ifdef REALLOCATE_BITMAPSETS
+	else
+	{
+		Bitmapset  *tmp = a;
+
+		a = (Bitmapset *) palloc(BITMAPSET_SIZE(tmp->nwords));
+		memcpy(a, tmp, BITMAPSET_SIZE(tmp->nwords));
+		pfree(tmp);
+	}
+#endif
 
 	a->words[wordnum] |= ((bitmapword) 1 << bitnum);
 	return a;
@@ -794,14 +843,24 @@ bms_del_member(Bitmapset *a, int x)
 {
 	int			wordnum,
 				bitnum;
+#ifdef REALLOCATE_BITMAPSETS
+	Bitmapset  *tmp = a;
+#endif
 
 	if (x < 0)
 		elog(ERROR, "negative bitmapset member not allowed");
 	if (a == NULL)
 		return NULL;
+	Assert(IsA(a, Bitmapset));
 	wordnum = WORDNUM(x);
 	bitnum = BITNUM(x);
 
+#ifdef REALLOCATE_BITMAPSETS
+	a = (Bitmapset *) palloc(BITMAPSET_SIZE(tmp->nwords));
+	memcpy(a, tmp, BITMAPSET_SIZE(tmp->nwords));
+	pfree(tmp);
+#endif
+
 	/* member can't exist.  Return 'a' unmodified */
 	if (unlikely(wordnum >= a->nwords))
 		return a;
@@ -839,6 +898,9 @@ bms_add_members(Bitmapset *a, const Bitmapset *b)
 	int			otherlen;
 	int			i;
 
+	Assert(a == NULL || IsA(a, Bitmapset));
+	Assert(b == NULL || IsA(b, Bitmapset));
+
 	/* Handle cases where either input is NULL */
 	if (a == NULL)
 		return bms_copy(b);
@@ -852,6 +914,13 @@ bms_add_members(Bitmapset *a, const Bitmapset *b)
 	}
 	else
 	{
+#ifdef REALLOCATE_BITMAPSETS
+		Bitmapset  *tmp = a;
+
+		a = (Bitmapset *) palloc(BITMAPSET_SIZE(tmp->nwords));
+		memcpy(a, tmp, BITMAPSET_SIZE(tmp->nwords));
+		pfree(tmp);
+#endif
 		result = a;
 		other = b;
 	}
@@ -884,6 +953,8 @@ bms_add_range(Bitmapset *a, int lower, int upper)
 				ushiftbits,
 				wordnum;
 
+	Assert(a == NULL || IsA(a, Bitmapset));
+
 	/* do nothing if nothing is called for, without further checking */
 	if (upper < lower)
 		return a;
@@ -902,9 +973,16 @@ bms_add_range(Bitmapset *a, int lower, int upper)
 	{
 		int			oldnwords = a->nwords;
 		int			i;
+#ifdef REALLOCATE_BITMAPSETS
+		Bitmapset  *tmp = a;
 
+		a = (Bitmapset *) palloc(BITMAPSET_SIZE(uwordnum + 1));
+		memcpy(a, tmp, BITMAPSET_SIZE(tmp->nwords));
+		pfree(tmp);
+#else
 		/* ensure we have enough words to store the upper bit */
 		a = (Bitmapset *) repalloc(a, BITMAPSET_SIZE(uwordnum + 1));
+#endif
 		a->nwords = uwordnum + 1;
 		/* zero out the enlarged portion */
 		i = oldnwords;
@@ -953,6 +1031,12 @@ bms_int_members(Bitmapset *a, const Bitmapset *b)
 	int			lastnonzero;
 	int			shortlen;
 	int			i;
+#ifdef REALLOCATE_BITMAPSETS
+	Bitmapset  *tmp = a;
+#endif
+
+	Assert(a == NULL || IsA(a, Bitmapset));
+	Assert(b == NULL || IsA(b, Bitmapset));
 
 	/* Handle cases where either input is NULL */
 	if (a == NULL)
@@ -962,6 +1046,13 @@ bms_int_members(Bitmapset *a, const Bitmapset *b)
 		pfree(a);
 		return NULL;
 	}
+
+#ifdef REALLOCATE_BITMAPSETS
+	a = (Bitmapset *) palloc(BITMAPSET_SIZE(tmp->nwords));
+	memcpy(a, tmp, BITMAPSET_SIZE(tmp->nwords));
+	pfree(tmp);
+#endif
+
 	/* Intersect b into a; we need never copy */
 	shortlen = Min(a->nwords, b->nwords);
 	lastnonzero = -1;
@@ -993,15 +1084,25 @@ Bitmapset *
 bms_del_members(Bitmapset *a, const Bitmapset *b)
 {
 	int			i;
+#ifdef REALLOCATE_BITMAPSETS
+	Bitmapset  *tmp = a;
+#endif
 
-	Assert(a == NULL || a->words[a->nwords - 1] != 0);
-	Assert(b == NULL || b->words[b->nwords - 1] != 0);
+	Assert(a == NULL || (IsA(a, Bitmapset) && a->words[a->nwords - 1] != 0));
+	Assert(b == NULL || (IsA(b, Bitmapset) && b->words[b->nwords - 1] != 0));
 
 	/* Handle cases where either input is NULL */
 	if (a == NULL)
 		return NULL;
 	if (b == NULL)
 		return a;
+
+#ifdef REALLOCATE_BITMAPSETS
+	a = (Bitmapset *) palloc(BITMAPSET_SIZE(tmp->nwords));
+	memcpy(a, tmp, BITMAPSET_SIZE(tmp->nwords));
+	pfree(tmp);
+#endif
+
 	/* Remove b's bits from a; we need never copy */
 	if (a->nwords > b->nwords)
 	{
@@ -1054,12 +1155,25 @@ bms_join(Bitmapset *a, Bitmapset *b)
 	Bitmapset  *other;
 	int			otherlen;
 	int			i;
+#ifdef REALLOCATE_BITMAPSETS
+	Bitmapset  *tmp = a;
+#endif
+
+	Assert(a == NULL || IsA(a, Bitmapset));
+	Assert(b == NULL || IsA(b, Bitmapset));
 
 	/* Handle cases where either input is NULL */
 	if (a == NULL)
 		return b;
 	if (b == NULL)
 		return a;
+
+#ifdef REALLOCATE_BITMAPSETS
+	a = (Bitmapset *) palloc(BITMAPSET_SIZE(tmp->nwords));
+	memcpy(a, tmp, BITMAPSET_SIZE(tmp->nwords));
+	pfree(tmp);
+#endif
+
 	/* Identify shorter and longer input; use longer one as result */
 	if (a->nwords < b->nwords)
 	{
@@ -1109,6 +1223,8 @@ bms_next_member(const Bitmapset *a, int prevbit)
 	int			wordnum;
 	bitmapword	mask;
 
+	Assert(a == NULL || IsA(a, Bitmapset));
+
 	if (a == NULL)
 		return -2;
 	nwords = a->nwords;
@@ -1168,6 +1284,8 @@ bms_prev_member(const Bitmapset *a, int prevbit)
 	int			ushiftbits;
 	bitmapword	mask;
 
+	Assert(a == NULL || IsA(a, Bitmapset));
+
 	/*
 	 * If set is NULL or if there are no more bits to the right then we've
 	 * nothing to do.
diff --git a/src/include/pg_config_manual.h b/src/include/pg_config_manual.h
index 8a6e67a445d..16c383ba7f7 100644
--- a/src/include/pg_config_manual.h
+++ b/src/include/pg_config_manual.h
@@ -335,6 +335,12 @@
  */
 /* #define COPY_PARSE_PLAN_TREES */
 
+/*
+ * Define this to force Bitmapset reallocation on each modification.  Helps
+ * to find hangling pointers to Bitmapset's.
+ */
+/* #define REALLOCATE_BITMAPSETS */
+
 /*
  * Define this to force all parse and plan trees to be passed through
  * outfuncs.c/readfuncs.c, to facilitate catching errors and omissions in
-- 
2.39.3 (Apple Git-145)