colexec: add casts from datum-backed types to bools

While investigating unrelated test failures, I added this cast, so we
might as well merge it.

Release note: None

pkg/col/coldataext/datum_vec.go

@@ -70,6 +70,12 @@ func (d *Datum) CompareDatum(dVec, other interface{}) int {
 	return d.Datum.Compare(dVec.(*datumVec).evalCtx, maybeUnwrapDatum(other))
 }
 
+// Cast returns the result of casting d to the type toType. dVec is the
+// datumVec that stores d and is used to supply the eval context.
+func (d *Datum) Cast(dVec interface{}, toType *types.T) (tree.Datum, error) {
+	return tree.PerformCast(dVec.(*datumVec).evalCtx, d.Datum, toType)
+}
+
 // Hash returns the hash of the datum as a byte slice.
 func (d *Datum) Hash(da *sqlbase.DatumAlloc) []byte {
 	ed := sqlbase.EncDatum{Datum: maybeUnwrapDatum(d)}

pkg/sql/colexec/cast_tmpl.go

@@ -56,7 +56,7 @@ const _RIGHT_CANONICAL_TYPE_FAMILY = types.UnknownFamily
 // _RIGHT_TYPE_WIDTH is the template variable.
 const _RIGHT_TYPE_WIDTH = 0
 
-func _CAST(to, from interface{}) {
+func _CAST(to, from, fromCol interface{}) {
 	colexecerror.InternalError("")
 }
 
@@ -104,7 +104,7 @@ func cast(inputVec, outputVec coldata.Vec, n int, sel []int) {
 								} else {
 									v := _L_UNSAFEGET(inputCol, i)
 									var r _R_GO_TYPE
-									_CAST(r, v)
+									_CAST(r, v, inputCol)
 									_R_SET(outputCol, i, r)
 								}
 							}
@@ -116,7 +116,7 @@ func cast(inputVec, outputVec coldata.Vec, n int, sel []int) {
 								} else {
 									v := _L_UNSAFEGET(inputCol, i)
 									var r _R_GO_TYPE
-									_CAST(r, v)
+									_CAST(r, v, inputCol)
 									_R_SET(outputCol, i, r)
 								}
 							}
@@ -127,15 +127,15 @@ func cast(inputVec, outputVec coldata.Vec, n int, sel []int) {
 							for _, i := range sel {
 								v := _L_UNSAFEGET(inputCol, i)
 								var r _R_GO_TYPE
-								_CAST(r, v)
+								_CAST(r, v, inputCol)
 								_R_SET(outputCol, i, r)
 							}
 						} else {
 							inputCol = _L_SLICE(inputCol, 0, n)
 							for execgen.RANGE(i, inputCol, 0, n) {
 								v := _L_UNSAFEGET(inputCol, i)
 								var r _R_GO_TYPE
-								_CAST(r, v)
+								_CAST(r, v, inputCol)
 								_R_SET(outputCol, i, r)
 							}
 						}

pkg/sql/colexec/execgen/cmd/execgen/cast_gen.go

@@ -30,8 +30,8 @@ func genCastOperators(inputFileContents string, wr io.Writer) error {
 	)
 	s := r.Replace(inputFileContents)
 
-	castRe := makeFunctionRegex("_CAST", 2)
-	s = castRe.ReplaceAllString(s, makeTemplateFunctionCall("Right.Cast", 2))
+	castRe := makeFunctionRegex("_CAST", 3)
+	s = castRe.ReplaceAllString(s, makeTemplateFunctionCall("Right.Cast", 3))
 
 	s = strings.ReplaceAll(s, "_L_SLICE", "execgen.SLICE")
 	s = strings.ReplaceAll(s, "_L_UNSAFEGET", "execgen.UNSAFEGET")

pkg/sql/colexec/execgen/cmd/execgen/overloads_base.go

@@ -344,7 +344,7 @@ type twoArgsResolvedOverloadRightWidthInfo struct {
 
 type assignFunc func(op *lastArgWidthOverload, targetElem, leftElem, rightElem, targetCol, leftCol, rightCol string) string
 type compareFunc func(targetElem, leftElem, rightElem, leftCol, rightCol string) string
-type castFunc func(to, from string) string
+type castFunc func(to, from, fromCol string) string
 
 // Assign produces a Go source string that assigns the "targetElem" variable to
 // the result of applying the overload to the two inputs, "leftElem" and
@@ -392,9 +392,9 @@ func (o *lastArgWidthOverload) Compare(
 		leftElem, rightElem, targetElem, leftElem, rightElem, targetElem, targetElem)
 }
 
-func (o *lastArgWidthOverload) Cast(to, from string) string {
+func (o *lastArgWidthOverload) Cast(to, from, fromCol string) string {
 	if o.CastFunc != nil {
-		if ret := o.CastFunc(to, from); ret != "" {
+		if ret := o.CastFunc(to, from, fromCol); ret != "" {
 			return ret
 		}
 	}

pkg/sql/colexec/execgen/cmd/execgen/overloads_cast.go

@@ -13,6 +13,7 @@ package main
 import (
 	"fmt"
 
+	"github.com/cockroachdb/cockroach/pkg/col/typeconv"
 	"github.com/cockroachdb/cockroach/pkg/sql/colexecbase/colexecerror"
 	"github.com/cockroachdb/cockroach/pkg/sql/types"
 )
@@ -56,45 +57,45 @@ func populateCastOverloads() {
 		}, castTypeCustomizers)
 }
 
-func intToDecimal(to, from string) string {
+func intToDecimal(to, from, _ string) string {
 	convStr := `
    %[1]s = *apd.New(int64(%[2]s), 0)
  `
 	return fmt.Sprintf(convStr, to, from)
 }
 
-func intToFloat() func(string, string) string {
-	return func(to, from string) string {
+func intToFloat() func(string, string, string) string {
+	return func(to, from, _ string) string {
 		convStr := `
 			%[1]s = float64(%[2]s)
 			`
 		return fmt.Sprintf(convStr, to, from)
 	}
 }
 
-func intToInt16(to, from string) string {
+func intToInt16(to, from, _ string) string {
 	convStr := `
    %[1]s = int16(%[2]s)
  `
 	return fmt.Sprintf(convStr, to, from)
 }
 
-func intToInt32(to, from string) string {
+func intToInt32(to, from, _ string) string {
 	convStr := `
    %[1]s = int32(%[2]s)
  `
 	return fmt.Sprintf(convStr, to, from)
 }
 
-func intToInt64(to, from string) string {
+func intToInt64(to, from, _ string) string {
 	convStr := `
    %[1]s = int64(%[2]s)
  `
 	return fmt.Sprintf(convStr, to, from)
 }
 
-func floatToInt(intWidth, floatWidth int32) func(string, string) string {
-	return func(to, from string) string {
+func floatToInt(intWidth, floatWidth int32) func(string, string, string) string {
+	return func(to, from, _ string) string {
 		convStr := `
 			if math.IsNaN(float64(%[2]s)) || %[2]s <= float%[4]d(math.MinInt%[3]d) || %[2]s >= float%[4]d(math.MaxInt%[3]d) {
 				colexecerror.ExpectedError(tree.ErrIntOutOfRange)
@@ -108,14 +109,14 @@ func floatToInt(intWidth, floatWidth int32) func(string, string) string {
 	}
 }
 
-func numToBool(to, from string) string {
+func numToBool(to, from, _ string) string {
 	convStr := `
 		%[1]s = %[2]s != 0
 	`
 	return fmt.Sprintf(convStr, to, from)
 }
 
-func floatToDecimal(to, from string) string {
+func floatToDecimal(to, from, _ string) string {
 	convStr := `
 		{
 			var tmpDec apd.Decimal
@@ -129,6 +130,19 @@ func floatToDecimal(to, from string) string {
 	return fmt.Sprintf(convStr, to, from)
 }
 
+func datumToBool(to, from, fromCol string) string {
+	convStr := `
+		{
+			_castedDatum, err := %[2]s.(*coldataext.Datum).Cast(%[3]s, types.Bool)
+			if err != nil {
+				colexecerror.ExpectedError(err)
+			}
+			%[1]s = _castedDatum == tree.DBoolTrue
+		}
+	`
+	return fmt.Sprintf(convStr, to, from, fromCol)
+}
+
 // castTypeCustomizer is a type customizer that changes how the templater
 // produces cast operator output for a particular type.
 type castTypeCustomizer interface {
@@ -200,6 +214,9 @@ func registerCastTypeCustomizers() {
 			registerCastTypeCustomizer(typePair{types.FloatFamily, anyWidth, toFamily, toWidth}, floatCastCustomizer{toFamily: toFamily, toWidth: toWidth})
 		}
 	}
+
+	// Casts from datum-backed types.
+	registerCastTypeCustomizer(typePair{typeconv.DatumVecCanonicalTypeFamily, anyWidth, types.BoolFamily, anyWidth}, datumCastCustomizer{toFamily: types.BoolFamily})
 }
 
 // boolCastCustomizer specifies casts from booleans.
@@ -220,8 +237,14 @@ type intCastCustomizer struct {
 	toWidth  int32
 }
 
+// datumCastCustomizer specifies casts from types that are backed by tree.Datum
+// to other types.
+type datumCastCustomizer struct {
+	toFamily types.Family
+}
+
 func (boolCastCustomizer) getCastFunc() castFunc {
-	return func(to, from string) string {
+	return func(to, from, _ string) string {
 		convStr := `
 			%[1]s = 0
 			if %[2]s {
@@ -233,7 +256,7 @@ func (boolCastCustomizer) getCastFunc() castFunc {
 }
 
 func (decimalCastCustomizer) getCastFunc() castFunc {
-	return func(to, from string) string {
+	return func(to, from, _ string) string {
 		return fmt.Sprintf("%[1]s = %[2]s.Sign() != 0", to, from)
 	}
 }
@@ -274,3 +297,13 @@ func (c intCastCustomizer) getCastFunc() castFunc {
 	// This code is unreachable, but the compiler cannot infer that.
 	return nil
 }
+
+func (c datumCastCustomizer) getCastFunc() castFunc {
+	switch c.toFamily {
+	case types.BoolFamily:
+		return datumToBool
+	}
+	colexecerror.InternalError(fmt.Sprintf("unexpectedly didn't find a cast from datum-backed type to %s", c.toFamily))
+	// This code is unreachable, but the compiler cannot infer that.
+	return nil
+}