v2-0001-Clean-up-my_log2-in-dynahash.c-adding-equivalents.patch

From c1f1dd163f671185bc0fba86acdd0b108007b711 Mon Sep 17 00:00:00 2001
From: Michael Paquier <michael@paquier.xyz>
Date: Mon, 1 Sep 2025 12:23:44 +0900
Subject: [PATCH v2] Clean up my_log2() in dynahash.c, adding equivalents to
 bitutils.h

---
 src/include/port/pg_bitutils.h           | 34 ++++++++++++++++++++++++
 src/include/utils/dynahash.h             | 20 --------------
 src/backend/executor/nodeAgg.c           |  3 +--
 src/backend/executor/nodeHash.c          |  7 +++--
 src/backend/replication/logical/worker.c |  3 +--
 src/backend/utils/hash/dynahash.c        | 23 +++-------------
 6 files changed, 43 insertions(+), 47 deletions(-)
 delete mode 100644 src/include/utils/dynahash.h

diff --git a/src/include/port/pg_bitutils.h b/src/include/port/pg_bitutils.h
index c7901bf8ddc0..5354d152a116 100644
--- a/src/include/port/pg_bitutils.h
+++ b/src/include/port/pg_bitutils.h
@@ -276,6 +276,40 @@ pg_ceil_log2_64(uint64 num)
 		return pg_leftmost_one_pos64(num - 1) + 1;
 }
 
+/*
+ * pg_ceil_log2_32_bound
+ *		Returns equivalent of ceil(log2(num)), with overflow safeguard
+ *		for pg_leftmost_one_pos32.
+ */
+static inline uint32
+pg_ceil_log2_32_bound(uint32 num)
+{
+	if (num > PG_INT32_MAX / 2)
+		num = PG_INT32_MAX / 2;
+
+	if (num < 2)
+		return 0;
+	else
+		return pg_leftmost_one_pos32(num - 1) + 1;
+}
+
+/*
+ * pg_ceil_log2_64_bound
+ *		Returns equivalent of ceil(log2(num)), with overflow safeguard
+ *		for pg_leftmost_one_pos64.
+ */
+static inline uint64
+pg_ceil_log2_64_bound(uint64 num)
+{
+	if (num > PG_INT64_MAX / 2)
+		num = PG_INT64_MAX / 2;
+
+	if (num < 2)
+		return 0;
+	else
+		return pg_leftmost_one_pos64(num - 1) + 1;
+}
+
 /*
  * With MSVC on x86_64 builds, try using native popcnt instructions via the
  * __popcnt and __popcnt64 intrinsics.  These don't work the same as GCC's
diff --git a/src/include/utils/dynahash.h b/src/include/utils/dynahash.h
deleted file mode 100644
index a4362d3f65e5..000000000000
--- a/src/include/utils/dynahash.h
+++ /dev/null
@@ -1,20 +0,0 @@
-/*-------------------------------------------------------------------------
- *
- * dynahash.h
- *	  POSTGRES dynahash.h file definitions
- *
- *
- * Portions Copyright (c) 1996-2025, PostgreSQL Global Development Group
- * Portions Copyright (c) 1994, Regents of the University of California
- *
- * IDENTIFICATION
- *		src/include/utils/dynahash.h
- *
- *-------------------------------------------------------------------------
- */
-#ifndef DYNAHASH_H
-#define DYNAHASH_H
-
-extern int	my_log2(int64 num);
-
-#endif							/* DYNAHASH_H */
diff --git a/src/backend/executor/nodeAgg.c b/src/backend/executor/nodeAgg.c
index 377e016d7322..b5fa9af9d992 100644
--- a/src/backend/executor/nodeAgg.c
+++ b/src/backend/executor/nodeAgg.c
@@ -267,7 +267,6 @@
 #include "utils/acl.h"
 #include "utils/builtins.h"
 #include "utils/datum.h"
-#include "utils/dynahash.h"
 #include "utils/expandeddatum.h"
 #include "utils/injection_point.h"
 #include "utils/logtape.h"
@@ -2115,7 +2114,7 @@ hash_choose_num_partitions(double input_groups, double hashentrysize,
 	npartitions = (int) dpartitions;
 
 	/* ceil(log2(npartitions)) */
-	partition_bits = my_log2(npartitions);
+	partition_bits = pg_ceil_log2_64_bound(npartitions);
 
 	/* make sure that we don't exhaust the hash bits */
 	if (partition_bits + used_bits >= 32)
diff --git a/src/backend/executor/nodeHash.c b/src/backend/executor/nodeHash.c
index 8d2201ab67fa..14d934ab42b2 100644
--- a/src/backend/executor/nodeHash.c
+++ b/src/backend/executor/nodeHash.c
@@ -36,7 +36,6 @@
 #include "executor/nodeHashjoin.h"
 #include "miscadmin.h"
 #include "port/pg_bitutils.h"
-#include "utils/dynahash.h"
 #include "utils/lsyscache.h"
 #include "utils/memutils.h"
 #include "utils/syscache.h"
@@ -340,7 +339,7 @@ MultiExecParallelHash(HashState *node)
 	 */
 	hashtable->curbatch = -1;
 	hashtable->nbuckets = pstate->nbuckets;
-	hashtable->log2_nbuckets = my_log2(hashtable->nbuckets);
+	hashtable->log2_nbuckets = pg_ceil_log2_64_bound(hashtable->nbuckets);
 	hashtable->totalTuples = pstate->total_tuples;
 
 	/*
@@ -480,7 +479,7 @@ ExecHashTableCreate(HashState *state)
 							&nbuckets, &nbatch, &num_skew_mcvs);
 
 	/* nbuckets must be a power of 2 */
-	log2_nbuckets = my_log2(nbuckets);
+	log2_nbuckets = pg_ceil_log2_64_bound(nbuckets);
 	Assert(nbuckets == (1 << log2_nbuckets));
 
 	/*
@@ -3499,7 +3498,7 @@ ExecParallelHashTableSetCurrentBatch(HashJoinTable hashtable, int batchno)
 		dsa_get_address(hashtable->area,
 						hashtable->batches[batchno].shared->buckets);
 	hashtable->nbuckets = hashtable->parallel_state->nbuckets;
-	hashtable->log2_nbuckets = my_log2(hashtable->nbuckets);
+	hashtable->log2_nbuckets = pg_ceil_log2_64_bound(hashtable->nbuckets);
 	hashtable->current_chunk = NULL;
 	hashtable->current_chunk_shared = InvalidDsaPointer;
 	hashtable->batches[batchno].at_least_one_chunk = false;
diff --git a/src/backend/replication/logical/worker.c b/src/backend/replication/logical/worker.c
index 22ad9051db3f..664db8096b26 100644
--- a/src/backend/replication/logical/worker.c
+++ b/src/backend/replication/logical/worker.c
@@ -268,7 +268,6 @@
 #include "storage/procarray.h"
 #include "tcop/tcopprot.h"
 #include "utils/acl.h"
-#include "utils/dynahash.h"
 #include "utils/guc.h"
 #include "utils/inval.h"
 #include "utils/lsyscache.h"
@@ -4911,7 +4910,7 @@ subxact_info_read(Oid subid, TransactionId xid)
 	len = sizeof(SubXactInfo) * subxact_data.nsubxacts;
 
 	/* we keep the maximum as a power of 2 */
-	subxact_data.nsubxacts_max = 1 << my_log2(subxact_data.nsubxacts);
+	subxact_data.nsubxacts_max = 1 << pg_ceil_log2_64_bound(subxact_data.nsubxacts);
 
 	/*
 	 * Allocate subxact information in the logical streaming context. We need
diff --git a/src/backend/utils/hash/dynahash.c b/src/backend/utils/hash/dynahash.c
index 1aeee5be42ac..6a86572ee61d 100644
--- a/src/backend/utils/hash/dynahash.c
+++ b/src/backend/utils/hash/dynahash.c
@@ -102,7 +102,6 @@
 #include "port/pg_bitutils.h"
 #include "storage/shmem.h"
 #include "storage/spin.h"
-#include "utils/dynahash.h"
 #include "utils/memutils.h"
 
 
@@ -547,7 +546,7 @@ hash_create(const char *tabname, int64 nelem, const HASHCTL *info, int flags)
 	if (flags & HASH_SEGMENT)
 	{
 		hctl->ssize = info->ssize;
-		hctl->sshift = my_log2(info->ssize);
+		hctl->sshift = pg_ceil_log2_64_bound(info->ssize);
 		/* ssize had better be a power of 2 */
 		Assert(hctl->ssize == (1L << hctl->sshift));
 	}
@@ -1812,26 +1811,12 @@ hash_corrupted(HTAB *hashp)
 		elog(FATAL, "hash table \"%s\" corrupted", hashp->tabname);
 }
 
-/* calculate ceil(log base 2) of num */
-int
-my_log2(int64 num)
-{
-	/*
-	 * guard against too-large input, which would be invalid for
-	 * pg_ceil_log2_*()
-	 */
-	if (num > PG_INT64_MAX / 2)
-		num = PG_INT64_MAX / 2;
-
-	return pg_ceil_log2_64(num);
-}
-
 /* calculate first power of 2 >= num, bounded to what will fit in a int64 */
 static int64
 next_pow2_int64(int64 num)
 {
-	/* my_log2's internal range check is sufficient */
-	return 1L << my_log2(num);
+	/* pg_ceil_log2_64_bound's internal range check is sufficient */
+	return 1L << pg_ceil_log2_64_bound(num);
 }
 
 /* calculate first power of 2 >= num, bounded to what will fit in an int */
@@ -1840,7 +1825,7 @@ next_pow2_int(int64 num)
 {
 	if (num > INT_MAX / 2)
 		num = INT_MAX / 2;
-	return 1 << my_log2(num);
+	return 1 << pg_ceil_log2_32_bound(num);
 }
 
 
-- 
2.51.0