more unconstify use

From e874e9fde3371bedbb8c5301a966c082a8369e2c Mon Sep 17 00:00:00 2001
From: Peter Eisentraut <peter@eisentraut.org>
Date: Tue, 29 Jan 2019 01:12:18 +0100
Subject: [PATCH v1 1/5] Remove useless casts

Some of these were uselessly casting away "const", some were just
nearby, but they where all unnecessary anyway.
---
 contrib/btree_gist/btree_utils_num.c | 24 ++++++++++++------------
 src/backend/catalog/heap.c           |  2 +-
 src/common/unicode_norm.c            |  2 +-
 3 files changed, 14 insertions(+), 14 deletions(-)

diff --git a/contrib/btree_gist/btree_utils_num.c b/contrib/btree_gist/btree_utils_num.c
index 29b0faf997..4d10bc93f3 100644
--- a/contrib/btree_gist/btree_utils_num.c
+++ b/contrib/btree_gist/btree_utils_num.c
@@ -185,10 +185,10 @@ gbt_num_union(GBT_NUMKEY *out, const GistEntryVector *entryvec, const gbtree_nin
 		c.upper = &cur[tinfo->size];
 		/* if out->lower > cur->lower, adopt cur as lower */
 		if (tinfo->f_gt(o.lower, c.lower, flinfo))
-			memcpy((void *) o.lower, (void *) c.lower, tinfo->size);
+			memcpy((void *) o.lower, c.lower, tinfo->size);
 		/* if out->upper < cur->upper, adopt cur as upper */
 		if (tinfo->f_lt(o.upper, c.upper, flinfo))
-			memcpy((void *) o.upper, (void *) c.upper, tinfo->size);
+			memcpy((void *) o.upper, c.upper, tinfo->size);
 	}
 
 	return out;
@@ -206,10 +206,10 @@ gbt_num_same(const GBT_NUMKEY *a, const GBT_NUMKEY *b, const gbtree_ninfo *tinfo
 	GBT_NUMKEY_R b1,
 				b2;
 
-	b1.lower = &(((GBT_NUMKEY *) a)[0]);
-	b1.upper = &(((GBT_NUMKEY *) a)[tinfo->size]);
-	b2.lower = &(((GBT_NUMKEY *) b)[0]);
-	b2.upper = &(((GBT_NUMKEY *) b)[tinfo->size]);
+	b1.lower = &(a[0]);
+	b1.upper = &(a[tinfo->size]);
+	b2.lower = &(b[0]);
+	b2.upper = &(b[tinfo->size]);
 
 	return (tinfo->f_eq(b1.lower, b2.lower, flinfo) &&
 			tinfo->f_eq(b1.upper, b2.upper, flinfo));
@@ -227,8 +227,8 @@ gbt_num_bin_union(Datum *u, GBT_NUMKEY *e, const gbtree_ninfo *tinfo, FmgrInfo *
 	if (!DatumGetPointer(*u))
 	{
 		*u = PointerGetDatum(palloc0(tinfo->indexsize));
-		memcpy((void *) &(((GBT_NUMKEY *) DatumGetPointer(*u))[0]), (void *) rd.lower, tinfo->size);
-		memcpy((void *) &(((GBT_NUMKEY *) DatumGetPointer(*u))[tinfo->size]), (void *) rd.upper, tinfo->size);
+		memcpy(&(((GBT_NUMKEY *) DatumGetPointer(*u))[0]), rd.lower, tinfo->size);
+		memcpy(&(((GBT_NUMKEY *) DatumGetPointer(*u))[tinfo->size]), rd.upper, tinfo->size);
 	}
 	else
 	{
@@ -236,10 +236,10 @@ gbt_num_bin_union(Datum *u, GBT_NUMKEY *e, const gbtree_ninfo *tinfo, FmgrInfo *
 
 		ur.lower = &(((GBT_NUMKEY *) DatumGetPointer(*u))[0]);
 		ur.upper = &(((GBT_NUMKEY *) DatumGetPointer(*u))[tinfo->size]);
-		if (tinfo->f_gt((void *) ur.lower, (void *) rd.lower, flinfo))
-			memcpy((void *) ur.lower, (void *) rd.lower, tinfo->size);
-		if (tinfo->f_lt((void *) ur.upper, (void *) rd.upper, flinfo))
-			memcpy((void *) ur.upper, (void *) rd.upper, tinfo->size);
+		if (tinfo->f_gt(ur.lower, rd.lower, flinfo))
+			memcpy((void *) ur.lower, rd.lower, tinfo->size);
+		if (tinfo->f_lt(ur.upper, rd.upper, flinfo))
+			memcpy((void *) ur.upper, rd.upper, tinfo->size);
 	}
 }
 
diff --git a/src/backend/catalog/heap.c b/src/backend/catalog/heap.c
index 06d18a1cfb..d0215a5eed 100644
--- a/src/backend/catalog/heap.c
+++ b/src/backend/catalog/heap.c
@@ -777,7 +777,7 @@ AddNewAttributeTuples(Oid new_rel_oid,
 		{
 			FormData_pg_attribute attStruct;
 
-			memcpy(&attStruct, (char *) SysAtt[i], sizeof(FormData_pg_attribute));
+			memcpy(&attStruct, SysAtt[i], sizeof(FormData_pg_attribute));
 
 			/* Fill in the correct relation OID in the copied tuple */
 			attStruct.attrelid = new_rel_oid;
diff --git a/src/common/unicode_norm.c b/src/common/unicode_norm.c
index d5f6d32e0f..6281f2222f 100644
--- a/src/common/unicode_norm.c
+++ b/src/common/unicode_norm.c
@@ -59,7 +59,7 @@ static pg_unicode_decomposition *
 get_code_entry(pg_wchar code)
 {
 	return bsearch(&(code),
-				   (void *) UnicodeDecompMain,
+				   UnicodeDecompMain,
 				   lengthof(UnicodeDecompMain),
 				   sizeof(pg_unicode_decomposition),
 				   conv_compare);

base-commit: 793c736d69091d385a967b2740cc93cfb7a7b076
-- 
2.20.1

From 8dc004406f742dce9c76d0b922f45fdfda174ea3 Mon Sep 17 00:00:00 2001
From: Peter Eisentraut <peter@eisentraut.org>
Date: Tue, 29 Jan 2019 01:16:24 +0100
Subject: [PATCH v1 2/5] More unconstify use

Replace casts whose only purpose is to cast away const with the
unconstify() macro.
---
 contrib/btree_gist/btree_utils_num.c      |  8 ++++----
 contrib/pgcrypto/imath.c                  |  2 +-
 contrib/pgcrypto/md5.c                    |  2 +-
 contrib/pgcrypto/pgp-compress.c           |  2 +-
 src/backend/access/brin/brin_pageops.c    |  8 ++++----
 src/backend/access/transam/xact.c         |  4 ++--
 src/backend/executor/spi.c                | 10 +++++-----
 src/backend/libpq/auth.c                  | 10 +++++-----
 src/backend/libpq/be-secure-openssl.c     |  2 +-
 src/backend/parser/parse_type.c           |  2 +-
 src/backend/replication/logical/message.c |  4 ++--
 src/backend/tcop/postgres.c               |  2 +-
 src/backend/utils/adt/formatting.c        |  2 +-
 src/backend/utils/mb/mbutils.c            | 20 ++++++++++----------
 src/backend/utils/misc/guc.c              |  2 +-
 src/bin/pg_basebackup/pg_basebackup.c     |  2 +-
 src/bin/pg_basebackup/walmethods.c        |  2 +-
 src/bin/pg_dump/compress_io.c             |  2 +-
 src/bin/psql/prompt.c                     |  2 +-
 src/fe_utils/print.c                      |  2 +-
 src/interfaces/libpq/fe-lobj.c            |  2 +-
 src/interfaces/libpq/pqexpbuffer.c        |  8 +++++---
 src/pl/tcl/pltcl.c                        |  4 ++--
 src/port/path.c                           |  6 +++---
 src/timezone/localtime.c                  |  2 +-
 25 files changed, 57 insertions(+), 55 deletions(-)

diff --git a/contrib/btree_gist/btree_utils_num.c b/contrib/btree_gist/btree_utils_num.c
index 4d10bc93f3..7564a403c7 100644
--- a/contrib/btree_gist/btree_utils_num.c
+++ b/contrib/btree_gist/btree_utils_num.c
@@ -185,10 +185,10 @@ gbt_num_union(GBT_NUMKEY *out, const GistEntryVector *entryvec, const gbtree_nin
 		c.upper = &cur[tinfo->size];
 		/* if out->lower > cur->lower, adopt cur as lower */
 		if (tinfo->f_gt(o.lower, c.lower, flinfo))
-			memcpy((void *) o.lower, c.lower, tinfo->size);
+			memcpy(unconstify(GBT_NUMKEY *, o.lower), c.lower, tinfo->size);
 		/* if out->upper < cur->upper, adopt cur as upper */
 		if (tinfo->f_lt(o.upper, c.upper, flinfo))
-			memcpy((void *) o.upper, c.upper, tinfo->size);
+			memcpy(unconstify(GBT_NUMKEY *, o.upper), c.upper, tinfo->size);
 	}
 
 	return out;
@@ -237,9 +237,9 @@ gbt_num_bin_union(Datum *u, GBT_NUMKEY *e, const gbtree_ninfo *tinfo, FmgrInfo *
 		ur.lower = &(((GBT_NUMKEY *) DatumGetPointer(*u))[0]);
 		ur.upper = &(((GBT_NUMKEY *) DatumGetPointer(*u))[tinfo->size]);
 		if (tinfo->f_gt(ur.lower, rd.lower, flinfo))
-			memcpy((void *) ur.lower, rd.lower, tinfo->size);
+			memcpy(unconstify(GBT_NUMKEY *, ur.lower), rd.lower, tinfo->size);
 		if (tinfo->f_lt(ur.upper, rd.upper, flinfo))
-			memcpy((void *) ur.upper, rd.upper, tinfo->size);
+			memcpy(unconstify(GBT_NUMKEY *, ur.upper), rd.upper, tinfo->size);
 	}
 }
 
diff --git a/contrib/pgcrypto/imath.c b/contrib/pgcrypto/imath.c
index b94a51b81a..c267ea6ab3 100644
--- a/contrib/pgcrypto/imath.c
+++ b/contrib/pgcrypto/imath.c
@@ -2050,7 +2050,7 @@ mp_int_read_cstring(mp_int z, mp_size radix, const char *str, char **end)
 		MP_SIGN(z) = MP_ZPOS;
 
 	if (end != NULL)
-		*end = (char *) str;
+		*end = unconstify(char *, str);
 
 	/*
 	 * Return a truncation error if the string has unprocessed characters
diff --git a/contrib/pgcrypto/md5.c b/contrib/pgcrypto/md5.c
index cac4e408ab..5bcfbfe28f 100644
--- a/contrib/pgcrypto/md5.c
+++ b/contrib/pgcrypto/md5.c
@@ -161,7 +161,7 @@ md5_loop(md5_ctxt *ctxt, const uint8 *input, unsigned len)
 		md5_calc(ctxt->md5_buf, ctxt);
 
 		for (i = gap; i + MD5_BUFLEN <= len; i += MD5_BUFLEN)
-			md5_calc((uint8 *) (input + i), ctxt);
+			md5_calc(unconstify(uint8 *, (input + i)), ctxt);
 
 		ctxt->md5_i = len - i;
 		memmove(ctxt->md5_buf, input + i, ctxt->md5_i);
diff --git a/contrib/pgcrypto/pgp-compress.c b/contrib/pgcrypto/pgp-compress.c
index 57efe73338..eaeb221877 100644
--- a/contrib/pgcrypto/pgp-compress.c
+++ b/contrib/pgcrypto/pgp-compress.c
@@ -117,7 +117,7 @@ compress_process(PushFilter *next, void *priv, const uint8 *data, int len)
 	 */
 	while (len > 0)
 	{
-		st->stream.next_in = (void *) data;
+		st->stream.next_in = unconstify(uint8 *, data);
 		st->stream.avail_in = len;
 		st->stream.next_out = st->buf;
 		st->stream.avail_out = st->buf_len;
diff --git a/src/backend/access/brin/brin_pageops.c b/src/backend/access/brin/brin_pageops.c
index 2eb354f948..2e83aa42f7 100644
--- a/src/backend/access/brin/brin_pageops.c
+++ b/src/backend/access/brin/brin_pageops.c
@@ -178,7 +178,7 @@ brin_doupdate(Relation idxrel, BlockNumber pagesPerRange,
 		brin_can_do_samepage_update(oldbuf, origsz, newsz))
 	{
 		START_CRIT_SECTION();
-		if (!PageIndexTupleOverwrite(oldpage, oldoff, (Item) newtup, newsz))
+		if (!PageIndexTupleOverwrite(oldpage, oldoff, (Item) unconstify(BrinTuple *, newtup), newsz))
 			elog(ERROR, "failed to replace BRIN tuple");
 		MarkBufferDirty(oldbuf);
 
@@ -195,7 +195,7 @@ brin_doupdate(Relation idxrel, BlockNumber pagesPerRange,
 			XLogRegisterData((char *) &xlrec, SizeOfBrinSamepageUpdate);
 
 			XLogRegisterBuffer(0, oldbuf, REGBUF_STANDARD);
-			XLogRegisterBufData(0, (char *) newtup, newsz);
+			XLogRegisterBufData(0, (char *) unconstify(BrinTuple *, newtup), newsz);
 
 			recptr = XLogInsert(RM_BRIN_ID, info);
 
@@ -252,7 +252,7 @@ brin_doupdate(Relation idxrel, BlockNumber pagesPerRange,
 			brin_page_init(newpage, BRIN_PAGETYPE_REGULAR);
 
 		PageIndexTupleDeleteNoCompact(oldpage, oldoff);
-		newoff = PageAddItem(newpage, (Item) newtup, newsz,
+		newoff = PageAddItem(newpage, (Item) unconstify(BrinTuple *, newtup), newsz,
 							 InvalidOffsetNumber, false, false);
 		if (newoff == InvalidOffsetNumber)
 			elog(ERROR, "failed to add BRIN tuple to new page");
@@ -287,7 +287,7 @@ brin_doupdate(Relation idxrel, BlockNumber pagesPerRange,
 			XLogRegisterData((char *) &xlrec, SizeOfBrinUpdate);
 
 			XLogRegisterBuffer(0, newbuf, REGBUF_STANDARD | (extended ? REGBUF_WILL_INIT : 0));
-			XLogRegisterBufData(0, (char *) newtup, newsz);
+			XLogRegisterBufData(0, (char *) unconstify(BrinTuple *, newtup), newsz);
 
 			/* revmap page */
 			XLogRegisterBuffer(1, revmapbuf, 0);
diff --git a/src/backend/access/transam/xact.c b/src/backend/access/transam/xact.c
index 92bda87804..e93262975d 100644
--- a/src/backend/access/transam/xact.c
+++ b/src/backend/access/transam/xact.c
@@ -5409,7 +5409,7 @@ XactLogCommitRecord(TimestampTz commit_time,
 	{
 		XLogRegisterData((char *) (&xl_twophase), sizeof(xl_xact_twophase));
 		if (xl_xinfo.xinfo & XACT_XINFO_HAS_GID)
-			XLogRegisterData((char *) twophase_gid, strlen(twophase_gid) + 1);
+			XLogRegisterData(unconstify(char *, twophase_gid), strlen(twophase_gid) + 1);
 	}
 
 	if (xl_xinfo.xinfo & XACT_XINFO_HAS_ORIGIN)
@@ -5537,7 +5537,7 @@ XactLogAbortRecord(TimestampTz abort_time,
 	{
 		XLogRegisterData((char *) (&xl_twophase), sizeof(xl_xact_twophase));
 		if (xl_xinfo.xinfo & XACT_XINFO_HAS_GID)
-			XLogRegisterData((char *) twophase_gid, strlen(twophase_gid) + 1);
+			XLogRegisterData(unconstify(char *, twophase_gid), strlen(twophase_gid) + 1);
 	}
 
 	if (xl_xinfo.xinfo & XACT_XINFO_HAS_ORIGIN)
diff --git a/src/backend/executor/spi.c b/src/backend/executor/spi.c
index 94a53e0e3f..70c03e0f60 100644
--- a/src/backend/executor/spi.c
+++ b/src/backend/executor/spi.c
@@ -1314,7 +1314,7 @@ SPI_cursor_open_internal(const char *name, SPIPlanPtr plan,
 	 * throws an error.
 	 */
 	spierrcontext.callback = _SPI_error_callback;
-	spierrcontext.arg = (void *) plansource->query_string;
+	spierrcontext.arg = unconstify(char *, plansource->query_string);
 	spierrcontext.previous = error_context_stack;
 	error_context_stack = &spierrcontext;
 
@@ -1753,7 +1753,7 @@ SPI_plan_get_cached_plan(SPIPlanPtr plan)
 
 	/* Setup error traceback support for ereport() */
 	spierrcontext.callback = _SPI_error_callback;
-	spierrcontext.arg = (void *) plansource->query_string;
+	spierrcontext.arg = unconstify(char *, plansource->query_string);
 	spierrcontext.previous = error_context_stack;
 	error_context_stack = &spierrcontext;
 
@@ -1884,7 +1884,7 @@ _SPI_prepare_plan(const char *src, SPIPlanPtr plan)
 	 * Setup error traceback support for ereport()
 	 */
 	spierrcontext.callback = _SPI_error_callback;
-	spierrcontext.arg = (void *) src;
+	spierrcontext.arg = unconstify(char *, src);
 	spierrcontext.previous = error_context_stack;
 	error_context_stack = &spierrcontext;
 
@@ -1989,7 +1989,7 @@ _SPI_prepare_oneshot_plan(const char *src, SPIPlanPtr plan)
 	 * Setup error traceback support for ereport()
 	 */
 	spierrcontext.callback = _SPI_error_callback;
-	spierrcontext.arg = (void *) src;
+	spierrcontext.arg = unconstify(char *, src);
 	spierrcontext.previous = error_context_stack;
 	error_context_stack = &spierrcontext;
 
@@ -2100,7 +2100,7 @@ _SPI_execute_plan(SPIPlanPtr plan, ParamListInfo paramLI,
 		List	   *stmt_list;
 		ListCell   *lc2;
 
-		spierrcontext.arg = (void *) plansource->query_string;
+		spierrcontext.arg = unconstify(char *, plansource->query_string);
 
 		/*
 		 * If this is a one-shot plan, we still need to do parse analysis.
diff --git a/src/backend/libpq/auth.c b/src/backend/libpq/auth.c
index 20fe98fb82..c42f7b8fe6 100644
--- a/src/backend/libpq/auth.c
+++ b/src/backend/libpq/auth.c
@@ -867,7 +867,7 @@ CheckSCRAMAuth(Port *port, char *shadow_pass, char **logdetail)
 	void	   *scram_opaq = NULL;
 	char	   *output = NULL;
 	int			outputlen = 0;
-	char	   *input;
+	const char *input;
 	int			inputlen;
 	int			result;
 	bool		initial;
@@ -964,14 +964,14 @@ CheckSCRAMAuth(Port *port, char *shadow_pass, char **logdetail)
 			if (inputlen == -1)
 				input = NULL;
 			else
-				input = (char *) pq_getmsgbytes(&buf, inputlen);
+				input = pq_getmsgbytes(&buf, inputlen);
 
 			initial = false;
 		}
 		else
 		{
 			inputlen = buf.len;
-			input = (char *) pq_getmsgbytes(&buf, buf.len);
+			input = pq_getmsgbytes(&buf, buf.len);
 		}
 		pq_getmsgend(&buf);
 
@@ -985,7 +985,7 @@ CheckSCRAMAuth(Port *port, char *shadow_pass, char **logdetail)
 		 * we pass 'logdetail' as NULL when doing a mock authentication,
 		 * because we should already have a better error message in that case
 		 */
-		result = pg_be_scram_exchange(scram_opaq, input, inputlen,
+		result = pg_be_scram_exchange(scram_opaq, unconstify(char *, input), inputlen,
 									  &output, &outputlen,
 									  logdetail);
 
@@ -2175,7 +2175,7 @@ CheckPAMAuth(Port *port, const char *user, const char *password)
 	 * later used inside the PAM conversation to pass the password to the
 	 * authentication module.
 	 */
-	pam_passw_conv.appdata_ptr = (char *) password; /* from password above,
+	pam_passw_conv.appdata_ptr = unconstify(char *, password); /* from password above,
 													 * not allocated */
 
 	/* Optionally, one can set the service name in pg_hba.conf */
diff --git a/src/backend/libpq/be-secure-openssl.c b/src/backend/libpq/be-secure-openssl.c
index a2779543ec..3a3d041039 100644
--- a/src/backend/libpq/be-secure-openssl.c
+++ b/src/backend/libpq/be-secure-openssl.c
@@ -854,7 +854,7 @@ load_dh_buffer(const char *buffer, size_t len)
 	BIO		   *bio;
 	DH		   *dh = NULL;
 
-	bio = BIO_new_mem_buf((char *) buffer, len);
+	bio = BIO_new_mem_buf(unconstify(char *, buffer), len);
 	if (bio == NULL)
 		return NULL;
 	dh = PEM_read_bio_DHparams(bio, NULL, NULL, NULL);
diff --git a/src/backend/parser/parse_type.c b/src/backend/parser/parse_type.c
index 8d57e83ac6..5d554633d2 100644
--- a/src/backend/parser/parse_type.c
+++ b/src/backend/parser/parse_type.c
@@ -739,7 +739,7 @@ typeStringToTypeName(const char *str)
 	 * Setup error traceback support in case of ereport() during parse
 	 */
 	ptserrcontext.callback = pts_error_callback;
-	ptserrcontext.arg = (void *) str;
+	ptserrcontext.arg = unconstify(char *, str);
 	ptserrcontext.previous = error_context_stack;
 	error_context_stack = &ptserrcontext;
 
diff --git a/src/backend/replication/logical/message.c b/src/backend/replication/logical/message.c
index 4b13189dde..0681cb4a2a 100644
--- a/src/backend/replication/logical/message.c
+++ b/src/backend/replication/logical/message.c
@@ -69,8 +69,8 @@ LogLogicalMessage(const char *prefix, const char *message, size_t size,
 
 	XLogBeginInsert();
 	XLogRegisterData((char *) &xlrec, SizeOfLogicalMessage);
-	XLogRegisterData((char *) prefix, xlrec.prefix_size);
-	XLogRegisterData((char *) message, size);
+	XLogRegisterData(unconstify(char *, prefix), xlrec.prefix_size);
+	XLogRegisterData(unconstify(char *, message), size);
 
 	/* allow origin filtering */
 	XLogSetRecordFlags(XLOG_INCLUDE_ORIGIN);
diff --git a/src/backend/tcop/postgres.c b/src/backend/tcop/postgres.c
index 36cfd507b2..8b4d94c9a1 100644
--- a/src/backend/tcop/postgres.c
+++ b/src/backend/tcop/postgres.c
@@ -1767,7 +1767,7 @@ exec_bind_message(StringInfo input_message)
 				 * trailing null.  This is grotty but is a big win when
 				 * dealing with very large parameter strings.
 				 */
-				pbuf.data = (char *) pvalue;
+				pbuf.data = unconstify(char *, pvalue);
 				pbuf.maxlen = plength + 1;
 				pbuf.len = plength;
 				pbuf.cursor = 0;
diff --git a/src/backend/utils/adt/formatting.c b/src/backend/utils/adt/formatting.c
index 096d862c1d..df1db7bc9f 100644
--- a/src/backend/utils/adt/formatting.c
+++ b/src/backend/utils/adt/formatting.c
@@ -3688,7 +3688,7 @@ to_timestamp(PG_FUNCTION_ARGS)
 	/* Use the specified time zone, if any. */
 	if (tm.tm_zone)
 	{
-		int			dterr = DecodeTimezone((char *) tm.tm_zone, &tz);
+		int			dterr = DecodeTimezone(unconstify(char *, tm.tm_zone), &tz);
 
 		if (dterr)
 			DateTimeParseError(dterr, text_to_cstring(date_txt), "timestamptz");
diff --git a/src/backend/utils/mb/mbutils.c b/src/backend/utils/mb/mbutils.c
index c8e5571d97..aa18c9ad3d 100644
--- a/src/backend/utils/mb/mbutils.c
+++ b/src/backend/utils/mb/mbutils.c
@@ -464,7 +464,7 @@ pg_convert(PG_FUNCTION_ARGS)
 	pg_verify_mbstr_len(src_encoding, src_str, len, false);
 
 	/* perform conversion */
-	dest_str = (char *) pg_do_encoding_conversion((unsigned char *) src_str,
+	dest_str = (char *) pg_do_encoding_conversion((unsigned char *) unconstify(char *, src_str),
 												  len,
 												  src_encoding,
 												  dest_encoding);
@@ -561,7 +561,7 @@ char *
 pg_any_to_server(const char *s, int len, int encoding)
 {
 	if (len <= 0)
-		return (char *) s;		/* empty string is always valid */
+		return unconstify(char *, s);		/* empty string is always valid */
 
 	if (encoding == DatabaseEncoding->encoding ||
 		encoding == PG_SQL_ASCII)
@@ -570,7 +570,7 @@ pg_any_to_server(const char *s, int len, int encoding)
 		 * No conversion is needed, but we must still validate the data.
 		 */
 		(void) pg_verify_mbstr(DatabaseEncoding->encoding, s, len, false);
-		return (char *) s;
+		return unconstify(char *, s);
 	}
 
 	if (DatabaseEncoding->encoding == PG_SQL_ASCII)
@@ -600,7 +600,7 @@ pg_any_to_server(const char *s, int len, int encoding)
 									(unsigned char) s[i])));
 			}
 		}
-		return (char *) s;
+		return unconstify(char *, s);
 	}
 
 	/* Fast path if we can use cached conversion function */
@@ -608,7 +608,7 @@ pg_any_to_server(const char *s, int len, int encoding)
 		return perform_default_encoding_conversion(s, len, true);
 
 	/* General case ... will not work outside transactions */
-	return (char *) pg_do_encoding_conversion((unsigned char *) s,
+	return (char *) pg_do_encoding_conversion((unsigned char *) unconstify(char *, s),
 											  len,
 											  encoding,
 											  DatabaseEncoding->encoding);
@@ -634,17 +634,17 @@ char *
 pg_server_to_any(const char *s, int len, int encoding)
 {
 	if (len <= 0)
-		return (char *) s;		/* empty string is always valid */
+		return unconstify(char *, s);		/* empty string is always valid */
 
 	if (encoding == DatabaseEncoding->encoding ||
 		encoding == PG_SQL_ASCII)
-		return (char *) s;		/* assume data is valid */
+		return unconstify(char *, s);		/* assume data is valid */
 
 	if (DatabaseEncoding->encoding == PG_SQL_ASCII)
 	{
 		/* No conversion is possible, but we must validate the result */
 		(void) pg_verify_mbstr(encoding, s, len, false);
-		return (char *) s;
+		return unconstify(char *, s);
 	}
 
 	/* Fast path if we can use cached conversion function */
@@ -652,7 +652,7 @@ pg_server_to_any(const char *s, int len, int encoding)
 		return perform_default_encoding_conversion(s, len, false);
 
 	/* General case ... will not work outside transactions */
-	return (char *) pg_do_encoding_conversion((unsigned char *) s,
+	return (char *) pg_do_encoding_conversion((unsigned char *) unconstify(char *, s),
 											  len,
 											  DatabaseEncoding->encoding,
 											  encoding);
@@ -687,7 +687,7 @@ perform_default_encoding_conversion(const char *src, int len,
 	}
 
 	if (flinfo == NULL)
-		return (char *) src;
+		return unconstify(char *, src);
 
 	/*
 	 * Allocate space for conversion result, being wary of integer overflow
diff --git a/src/backend/utils/misc/guc.c b/src/backend/utils/misc/guc.c
index 8681ada33a..57595cfb95 100644
--- a/src/backend/utils/misc/guc.c
+++ b/src/backend/utils/misc/guc.c
@@ -4897,7 +4897,7 @@ add_placeholder_variable(const char *name, int elevel)
 
 	if (!add_guc_variable((struct config_generic *) var, elevel))
 	{
-		free((void *) gen->name);
+		free(unconstify(char *, gen->name));
 		free(var);
 		return NULL;
 	}
diff --git a/src/bin/pg_basebackup/pg_basebackup.c b/src/bin/pg_basebackup/pg_basebackup.c
index 594d67c9e9..3d2d4cd0b9 100644
--- a/src/bin/pg_basebackup/pg_basebackup.c
+++ b/src/bin/pg_basebackup/pg_basebackup.c
@@ -1970,7 +1970,7 @@ BaseBackup(void)
 		 */
 		if (format == 'p' && !PQgetisnull(res, i, 1))
 		{
-			char	   *path = (char *) get_tablespace_mapping(PQgetvalue(res, i, 1));
+			char	   *path = unconstify(char *, get_tablespace_mapping(PQgetvalue(res, i, 1)));
 
 			verify_dir_is_empty_or_create(path, &made_tablespace_dirs, &found_tablespace_dirs);
 		}
diff --git a/src/bin/pg_basebackup/walmethods.c b/src/bin/pg_basebackup/walmethods.c
index 7410af3e63..165b3a1e89 100644
--- a/src/bin/pg_basebackup/walmethods.c
+++ b/src/bin/pg_basebackup/walmethods.c
@@ -496,7 +496,7 @@ tar_write(Walfile f, const void *buf, size_t count)
 #ifdef HAVE_LIBZ
 	else
 	{
-		if (!tar_write_compressed_data((void *) buf, count, false))
+		if (!tar_write_compressed_data(unconstify(void *, buf), count, false))
 			return -1;
 		((TarMethodFile *) f)->currpos += count;
 		return count;
diff --git a/src/bin/pg_dump/compress_io.c b/src/bin/pg_dump/compress_io.c
index e34e6c5618..d904ec62ad 100644
--- a/src/bin/pg_dump/compress_io.c
+++ b/src/bin/pg_dump/compress_io.c
@@ -312,7 +312,7 @@ static void
 WriteDataToArchiveZlib(ArchiveHandle *AH, CompressorState *cs,
 					   const char *data, size_t dLen)
 {
-	cs->zp->next_in = (void *) data;
+	cs->zp->next_in = (void *) unconstify(char *, data);
 	cs->zp->avail_in = dLen;
 	DeflateCompressorZlib(AH, cs, false);
 
diff --git a/src/bin/psql/prompt.c b/src/bin/psql/prompt.c
index 73394dc828..4514cf8551 100644
--- a/src/bin/psql/prompt.c
+++ b/src/bin/psql/prompt.c
@@ -181,7 +181,7 @@ get_prompt(promptStatus_t status, ConditionalStack cstack)
 				case '5':
 				case '6':
 				case '7':
-					*buf = (char) strtol(p, (char **) &p, 8);
+					*buf = (char) strtol(p, unconstify(char **, &p), 8);
 					--p;
 					break;
 				case 'R':
diff --git a/src/fe_utils/print.c b/src/fe_utils/print.c
index 4f84c24dac..779a95e8bc 100644
--- a/src/fe_utils/print.c
+++ b/src/fe_utils/print.c
@@ -3250,7 +3250,7 @@ printTableCleanup(printTableContent *const content)
 		for (i = 0; i < content->nrows * content->ncolumns; i++)
 		{
 			if (content->cellmustfree[i])
-				free((char *) content->cells[i]);
+				free(unconstify(char *, content->cells[i]));
 		}
 		free(content->cellmustfree);
 		content->cellmustfree = NULL;
diff --git a/src/interfaces/libpq/fe-lobj.c b/src/interfaces/libpq/fe-lobj.c
index 3c6f11a7d7..6866d64538 100644
--- a/src/interfaces/libpq/fe-lobj.c
+++ b/src/interfaces/libpq/fe-lobj.c
@@ -341,7 +341,7 @@ lo_write(PGconn *conn, int fd, const char *buf, size_t len)
 
 	argv[1].isint = 0;
 	argv[1].len = (int) len;
-	argv[1].u.ptr = (int *) buf;
+	argv[1].u.ptr = (int *) unconstify(char *, buf);
 
 	res = PQfn(conn, conn->lobjfuncs->fn_lo_write,
 			   &retval, &result_len, 1, argv, 2);
diff --git a/src/interfaces/libpq/pqexpbuffer.c b/src/interfaces/libpq/pqexpbuffer.c
index 498f82bd99..dc7c3ea07d 100644
--- a/src/interfaces/libpq/pqexpbuffer.c
+++ b/src/interfaces/libpq/pqexpbuffer.c
@@ -36,6 +36,8 @@
 
 /* All "broken" PQExpBuffers point to this string. */
 static const char oom_buffer[1] = "";
+/* Need a char * for unconstify() compatiblity */
+static const char * oom_buffer_ptr = oom_buffer;
 
 static bool appendPQExpBufferVA(PQExpBuffer str, const char *fmt, va_list args) pg_attribute_printf(2, 0);
 
@@ -57,7 +59,7 @@ markPQExpBufferBroken(PQExpBuffer str)
 	 * to put oom_buffer in read-only storage, so that anyone who tries to
 	 * scribble on a broken PQExpBuffer will get a failure.
 	 */
-	str->data = (char *) oom_buffer;
+	str->data = unconstify(char *, oom_buffer_ptr);
 	str->len = 0;
 	str->maxlen = 0;
 }
@@ -91,7 +93,7 @@ initPQExpBuffer(PQExpBuffer str)
 	str->data = (char *) malloc(INITIAL_EXPBUFFER_SIZE);
 	if (str->data == NULL)
 	{
-		str->data = (char *) oom_buffer;	/* see comment above */
+		str->data = unconstify(char *, oom_buffer_ptr);	/* see comment above */
 		str->maxlen = 0;
 		str->len = 0;
 	}
@@ -130,7 +132,7 @@ termPQExpBuffer(PQExpBuffer str)
 	if (str->data != oom_buffer)
 		free(str->data);
 	/* just for luck, make the buffer validly empty. */
-	str->data = (char *) oom_buffer;	/* see comment above */
+	str->data = unconstify(char *, oom_buffer_ptr);	/* see comment above */
 	str->maxlen = 0;
 	str->len = 0;
 }
diff --git a/src/pl/tcl/pltcl.c b/src/pl/tcl/pltcl.c
index bfbf62305c..76c9afc339 100644
--- a/src/pl/tcl/pltcl.c
+++ b/src/pl/tcl/pltcl.c
@@ -610,7 +610,7 @@ call_pltcl_start_proc(Oid prolang, bool pltrusted)
 
 	/* Set up errcontext callback to make errors more helpful */
 	errcallback.callback = start_proc_error_callback;
-	errcallback.arg = (void *) gucname;
+	errcallback.arg = unconstify(char *, gucname);
 	errcallback.previous = error_context_stack;
 	error_context_stack = &errcallback;
 
@@ -3081,7 +3081,7 @@ pltcl_set_tuple_values(Tcl_Interp *interp, const char *arrayname,
 		else
 			Tcl_UnsetVar2(interp, *arrptr, *nameptr, 0);
 
-		pfree((char *) attname);
+		pfree(unconstify(char *, attname));
 	}
 }
 
diff --git a/src/port/path.c b/src/port/path.c
index 661017f877..4b214e89e4 100644
--- a/src/port/path.c
+++ b/src/port/path.c
@@ -106,7 +106,7 @@ first_dir_separator(const char *filename)
 
 	for (p = skip_drive(filename); *p; p++)
 		if (IS_DIR_SEP(*p))
-			return (char *) p;
+			return unconstify(char *, p);
 	return NULL;
 }
 
@@ -124,7 +124,7 @@ first_path_var_separator(const char *pathlist)
 	/* skip_drive is not needed */
 	for (p = pathlist; *p; p++)
 		if (IS_PATH_VAR_SEP(*p))
-			return (char *) p;
+			return unconstify(char *, p);
 	return NULL;
 }
 
@@ -143,7 +143,7 @@ last_dir_separator(const char *filename)
 	for (p = skip_drive(filename); *p; p++)
 		if (IS_DIR_SEP(*p))
 			ret = p;
-	return (char *) ret;
+	return unconstify(char *, ret);
 }
 
 
diff --git a/src/timezone/localtime.c b/src/timezone/localtime.c
index 96e62aff3b..9fe43135fe 100644
--- a/src/timezone/localtime.c
+++ b/src/timezone/localtime.c
@@ -1364,7 +1364,7 @@ localsub(struct state const *sp, pg_time_t const *timep,
 	if (result)
 	{
 		result->tm_isdst = ttisp->tt_isdst;
-		result->tm_zone = (char *) &sp->chars[ttisp->tt_abbrind];
+		result->tm_zone = unconstify(char *, &sp->chars[ttisp->tt_abbrind]);
 	}
 	return result;
 }
-- 
2.20.1