opt/optgen: compile string and integer literals as Go values

Previously, optgen would sometimes compile string and integer literals,
e.g., `"foo"` and `1`, as Go strings and integers, and other times as
`*tree.DString`s and `*tree.DInt`s, depending on the context. Now, these
literals are always compiled as Go values. In addition to helping
prevent confusion, this can help avoid unnecessary allocations for
datums when they are not needed, e.g., see `NormalizeLikeAny`.

Release note: None

Author: mgartner

pkg/sql/opt/norm/general_funcs.go

@@ -1540,6 +1540,11 @@ func (c *CustomFuncs) CanAddConstInts(first tree.Datum, second tree.Datum) bool
 	return ok
 }
 
+// DInt returns a new *tree.DInt with the given integer value.
+func (c *CustomFuncs) DInt(i tree.DInt) *tree.DInt {
+	return tree.NewDInt(i)
+}
+
 // IntConst constructs a Const holding a DInt.
 func (c *CustomFuncs) IntConst(d *tree.DInt) opt.ScalarExpr {
 	return c.f.ConstructConst(d, types.Int)
@@ -1562,9 +1567,9 @@ func (c *CustomFuncs) StringFromConst(expr opt.ScalarExpr) (string, bool) {
 
 // ConstStringEquals returns true if e is a constant string expression and is
 // equal to other.
-func (c *CustomFuncs) ConstStringEquals(e opt.ScalarExpr, other *tree.DString) bool {
+func (c *CustomFuncs) ConstStringEquals(e opt.ScalarExpr, other string) bool {
 	if eStr, ok := c.StringFromConst(e); ok {
-		return eStr == string(*other)
+		return eStr == other
 	}
 	return false
 }

pkg/sql/opt/norm/rules/decorrelate.opt

@@ -707,7 +707,7 @@
     $left:*
     $right:(Limit $input:* (Const $limit:*) $ordering:*) &
         (HasOuterCols $right) &
-        (IsGreaterThan $limit 1)
+        (IsGreaterThan $limit (DInt 1))
     $on:*
     $private:*
 )

pkg/sql/opt/norm/rules/groupby.opt

@@ -324,7 +324,7 @@
 (ConstructProjectionFromDistinctOn
     (Limit
         $input
-        (IntConst 1)
+        (IntConst (DInt 1))
         (GroupingInputOrdering $groupingPrivate)
     )
     (MakeEmptyColSet)
@@ -610,7 +610,7 @@
 #      a. The aggregate only references cols from the Window operator's input.
 #      b. The aggregate is a ConstAgg (or ConstNotNull, AnyNotNull, or FirstAgg)
 #         that passes through the result of a window function.
-# 
+#
 # Assuming all of the above are satisfied, each GroupBy aggregate that only
 # references the Window's input can be left alone (5a). Then, each ConstAgg
 # referencing a window function can be replaced by that function (5b).

pkg/sql/opt/norm/rules/scalar.opt

@@ -240,7 +240,11 @@ $input
     [
         (Subquery
             (Project
-                (Limit $input (IntConst 1) (EmptyOrdering))
+                (Limit
+                    $input
+                    (IntConst (DInt 1))
+                    (EmptyOrdering)
+                )
                 [ (ProjectionsItem (True) (MakeBoolCol)) ]
                 (MakeEmptyColSet)
             )

pkg/sql/opt/optgen/cmd/optgen/explorer_gen.go

@@ -32,7 +32,6 @@ func (g *explorerGen) generate(compiled *lang.CompiledExpr, w io.Writer) {
 	g.w.writeIndent("\"github.com/cockroachdb/cockroach/pkg/sql/opt\"\n")
 	g.w.writeIndent("\"github.com/cockroachdb/cockroach/pkg/sql/opt/memo\"\n")
 	g.w.writeIndent("\"github.com/cockroachdb/cockroach/pkg/sql/opt/props/physical\"\n")
-	g.w.writeIndent("\"github.com/cockroachdb/cockroach/pkg/sql/sem/tree\"\n")
 	g.w.unnest(")\n\n")
 
 	g.genDispatcher()

pkg/sql/opt/optgen/cmd/optgen/rule_gen.go

@@ -916,12 +916,12 @@ func (g *newRuleGen) genNestedExpr(e lang.Expr) {
 		g.w.write("%s", string(t.Result.Label))
 
 	case *lang.StringExpr:
-		// Literal string expressions construct DString datums.
-		g.w.write("tree.NewDString(%s)", t)
+		// Literal string expressions construct Go strings.
+		g.w.write("%s", t)
 
 	case *lang.NumberExpr:
-		// Literal numeric expressions construct DInt datums.
-		g.w.write("tree.NewDInt(%s)", t)
+		// Literal numeric expressions construct Go ints.
+		g.w.write("%s", t)
 
 	case *lang.NameExpr:
 		// OpName literal expressions construct an op identifier like SelectOp,

pkg/sql/opt/optgen/cmd/optgen/testdata/explorer

@@ -78,7 +78,6 @@ import (
 	"github.com/cockroachdb/cockroach/pkg/sql/opt"
 	"github.com/cockroachdb/cockroach/pkg/sql/opt/memo"
 	"github.com/cockroachdb/cockroach/pkg/sql/opt/props/physical"
-	"github.com/cockroachdb/cockroach/pkg/sql/sem/tree"
 )
 
 func (_e *explorer) exploreGroupMember(
@@ -270,7 +269,6 @@ import (
 	"github.com/cockroachdb/cockroach/pkg/sql/opt"
 	"github.com/cockroachdb/cockroach/pkg/sql/opt/memo"
 	"github.com/cockroachdb/cockroach/pkg/sql/opt/props/physical"
-	"github.com/cockroachdb/cockroach/pkg/sql/sem/tree"
 )
 
 func (_e *explorer) exploreGroupMember(
@@ -393,7 +391,6 @@ import (
 	"github.com/cockroachdb/cockroach/pkg/sql/opt"
 	"github.com/cockroachdb/cockroach/pkg/sql/opt/memo"
 	"github.com/cockroachdb/cockroach/pkg/sql/opt/props/physical"
-	"github.com/cockroachdb/cockroach/pkg/sql/sem/tree"
 )
 
 func (_e *explorer) exploreGroupMember(
@@ -550,7 +547,6 @@ import (
 	"github.com/cockroachdb/cockroach/pkg/sql/opt"
 	"github.com/cockroachdb/cockroach/pkg/sql/opt/memo"
 	"github.com/cockroachdb/cockroach/pkg/sql/opt/props/physical"
-	"github.com/cockroachdb/cockroach/pkg/sql/sem/tree"
 )
 
 func (_e *explorer) exploreGroupMember(

pkg/sql/opt/xform/rules/groupby.opt

@@ -60,7 +60,7 @@
             $input
             [ (FiltersItem (IsNot $variable (Null (AnyType)))) ]
         )
-        (IntConst 1)
+        (IntConst (DInt 1))
         (MakeOrderingChoiceFromColumn (OpName $agg) $col)
     )
     [ (AggregationsItem (ConstAgg $variable) $aggPrivate) ]
@@ -108,7 +108,7 @@
 (MakeProjectFromPassthroughAggs
     (Limit
         $input
-        (IntConst 1)
+        (IntConst (DInt 1))
         (MakeOrderingChoiceFromColumn Min $col)
     )
     $aggregations
@@ -140,7 +140,7 @@
 (MakeProjectFromPassthroughAggs
     (Limit
         $input
-        (IntConst 1)
+        (IntConst (DInt 1))
         (MakeOrderingChoiceFromColumn Max $col)
     )
     $aggregations