Replace SQLValueFunction by COERCE_SQL_SYNTAX

This switch impacts 9 patterns related to a SQL-mandated special syntax
for function calls:
- LOCALTIME [ ( typmod ) ]
- LOCALTIMESTAMP [ ( typmod ) ]
- CURRENT_TIME [ ( typmod ) ]
- CURRENT_TIMESTAMP [ ( typmod ) ]
- CURRENT_DATE

Five new entries are added to pg_proc to compensate the removal of
SQLValueFunction to provide backward-compatibility and making this
change transparent for the end-user (for example for the attribute
generated when a keyword is specified in a SELECT or in a FROM clause
without an alias, or when specifying something else than an Iconst to
the parser).

The parser included a set of checks coming from the files in charge of
holding the C functions used for the SQLValueFunction calls (as of
transformSQLValueFunction()), which are now moved within each function's
execution path, so this reduces the dependencies between the execution
and the parsing steps.  As of this change, all the SQL keywords use the
same paths for their work, relying only on COERCE_SQL_SYNTAX.  Like
fb32748, no performance difference has been noticed, while the perf
profiles get reduced with ExecEvalSQLValueFunction() gone.

Bump catalog version.

Reviewed-by: Corey Huinker, Ted Yu
Discussion: https://postgr.es/m/YzaG3MoryCguUOym@paquier.xyz

6 files changed, 18 insertions, 50 deletions

diff --git a/src/include/catalog/catversion.h b/src/include/catalog/catversion.h
index ac2043f6cc0..49e9dc4a94b 100644
--- a/src/include/catalog/catversion.h
+++ b/src/include/catalog/catversion.h
@@ -57,6 +57,6 @@
  */
 
 /*							yyyymmddN */
-#define CATALOG_VERSION_NO	202211201
+#define CATALOG_VERSION_NO	202211211
 
 #endif
diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat
index fd2559442e5..f15aa2dbb1b 100644
--- a/src/include/catalog/pg_proc.dat
+++ b/src/include/catalog/pg_proc.dat
@@ -1520,6 +1520,23 @@
 { oid => '9977', descr => 'system user name',
   proname => 'system_user', provolatile => 's', prorettype => 'text',
   proargtypes => '', prosrc => 'system_user' },
+{ oid => '9978', descr => 'current date',
+  proname => 'current_date', provolatile => 's', prorettype => 'date',
+  proargtypes => '', prosrc => 'current_date' },
+{ oid => '9979', descr => 'current time',
+  proname => 'current_time', proisstrict => 'f', provolatile => 's',
+  prorettype => 'timetz', proargtypes => 'int4', prosrc => 'current_time' },
+{ oid => '9980', descr => 'current timestamp',
+  proname => 'current_timestamp', proisstrict => 'f', provolatile => 's',
+  prorettype => 'timestamptz', proargtypes => 'int4',
+  prosrc => 'current_timestamp' },
+{ oid => '9981', descr => 'local time',
+  proname => 'localtime', proisstrict => 'f', provolatile => 's',
+  prorettype => 'time', proargtypes => 'int4', prosrc => 'sql_localtime' },
+{ oid => '9982', descr => 'local timestamp',
+  proname => 'localtimestamp', proisstrict => 'f', provolatile => 's',
+  prorettype => 'timestamp', proargtypes => 'int4',
+  prosrc => 'sql_localtimestamp' },
 
 { oid => '744',
   proname => 'array_eq', prorettype => 'bool',
diff --git a/src/include/executor/execExpr.h b/src/include/executor/execExpr.h
index e14f15d435b..0557302b922 100644
--- a/src/include/executor/execExpr.h
+++ b/src/include/executor/execExpr.h
@@ -170,7 +170,6 @@ typedef enum ExprEvalOp
 	EEOP_DISTINCT,
 	EEOP_NOT_DISTINCT,
 	EEOP_NULLIF,
-	EEOP_SQLVALUEFUNCTION,
 	EEOP_CURRENTOFEXPR,
 	EEOP_NEXTVALUEEXPR,
 	EEOP_ARRAYEXPR,
@@ -416,12 +415,6 @@ typedef struct ExprEvalStep
 			FunctionCallInfo fcinfo_data_in;
 		}			iocoerce;
 
-		/* for EEOP_SQLVALUEFUNCTION */
-		struct
-		{
-			SQLValueFunction *svf;
-		}			sqlvaluefunction;
-
 		/* for EEOP_NEXTVALUEEXPR */
 		struct
 		{
@@ -741,7 +734,6 @@ extern void ExecEvalParamExec(ExprState *state, ExprEvalStep *op,
 							  ExprContext *econtext);
 extern void ExecEvalParamExtern(ExprState *state, ExprEvalStep *op,
 								ExprContext *econtext);
-extern void ExecEvalSQLValueFunction(ExprState *state, ExprEvalStep *op);
 extern void ExecEvalCurrentOfExpr(ExprState *state, ExprEvalStep *op);
 extern void ExecEvalNextValueExpr(ExprState *state, ExprEvalStep *op);
 extern void ExecEvalRowNull(ExprState *state, ExprEvalStep *op,
diff --git a/src/include/nodes/primnodes.h b/src/include/nodes/primnodes.h
index f6dd27edcc1..74f228d9598 100644
--- a/src/include/nodes/primnodes.h
+++ b/src/include/nodes/primnodes.h
@@ -1293,39 +1293,6 @@ typedef struct MinMaxExpr
 } MinMaxExpr;
 
 /*
- * SQLValueFunction - parameterless functions with special grammar productions
- *
- * The SQL standard categorizes some of these as <datetime value function>
- * and others as <general value specification>.  We call 'em SQLValueFunctions
- * for lack of a better term.  We store type and typmod of the result so that
- * some code doesn't need to know each function individually, and because
- * we would need to store typmod anyway for some of the datetime functions.
- * Note that currently, all variants return non-collating datatypes, so we do
- * not need a collation field; also, all these functions are stable.
- */
-typedef enum SQLValueFunctionOp
-{
-	SVFOP_CURRENT_DATE,
-	SVFOP_CURRENT_TIME,
-	SVFOP_CURRENT_TIME_N,
-	SVFOP_CURRENT_TIMESTAMP,
-	SVFOP_CURRENT_TIMESTAMP_N,
-	SVFOP_LOCALTIME,
-	SVFOP_LOCALTIME_N,
-	SVFOP_LOCALTIMESTAMP,
-	SVFOP_LOCALTIMESTAMP_N
-} SQLValueFunctionOp;
-
-typedef struct SQLValueFunction
-{
-	Expr		xpr;
-	SQLValueFunctionOp op;		/* which function this is */
-	Oid			type;			/* result type/typmod */
-	int32		typmod;
-	int			location;		/* token location, or -1 if unknown */
-} SQLValueFunction;
-
-/*
  * XmlExpr - various SQL/XML functions requiring special grammar productions
  *
  * 'name' carries the "NAME foo" argument (already XML-escaped).
diff --git a/src/include/utils/date.h b/src/include/utils/date.h
index 0bbe8891285..fad48787229 100644
--- a/src/include/utils/date.h
+++ b/src/include/utils/date.h
@@ -96,7 +96,6 @@ TimeTzADTPGetDatum(const TimeTzADT *X)
 
 
 /* date.c */
-extern int32 anytime_typmod_check(bool istz, int32 typmod);
 extern double date2timestamp_no_overflow(DateADT dateVal);
 extern Timestamp date2timestamp_opt_overflow(DateADT dateVal, int *overflow);
 extern TimestampTz date2timestamptz_opt_overflow(DateADT dateVal, int *overflow);
@@ -104,9 +103,6 @@ extern int32 date_cmp_timestamp_internal(DateADT dateVal, Timestamp dt2);
 extern int32 date_cmp_timestamptz_internal(DateADT dateVal, TimestampTz dt2);
 
 extern void EncodeSpecialDate(DateADT dt, char *str);
-extern DateADT GetSQLCurrentDate(void);
-extern TimeTzADT *GetSQLCurrentTime(int32 typmod);
-extern TimeADT GetSQLLocalTime(int32 typmod);
 extern int	time2tm(TimeADT time, struct pg_tm *tm, fsec_t *fsec);
 extern int	timetz2tm(TimeTzADT *time, struct pg_tm *tm, fsec_t *fsec, int *tzp);
 extern int	tm2time(struct pg_tm *tm, fsec_t fsec, TimeADT *result);
diff --git a/src/include/utils/timestamp.h b/src/include/utils/timestamp.h
index 76b7b4a3ca1..7fd0b58825c 100644
--- a/src/include/utils/timestamp.h
+++ b/src/include/utils/timestamp.h
@@ -93,11 +93,7 @@ extern PGDLLIMPORT TimestampTz PgReloadTime;
 
 /* Internal routines (not fmgr-callable) */
 
-extern int32 anytimestamp_typmod_check(bool istz, int32 typmod);
-
 extern TimestampTz GetCurrentTimestamp(void);
-extern TimestampTz GetSQLCurrentTimestamp(int32 typmod);
-extern Timestamp GetSQLLocalTimestamp(int32 typmod);
 extern void TimestampDifference(TimestampTz start_time, TimestampTz stop_time,
 								long *secs, int *microsecs);
 extern long TimestampDifferenceMilliseconds(TimestampTz start_time,