diff --git a/evaluator/builtin/builtin.go b/evaluator/builtin.go
similarity index 99%
rename from evaluator/builtin/builtin.go
rename to evaluator/builtin.go
index 9367edb1c7..2953f0c95a 100644
--- a/evaluator/builtin/builtin.go
+++ b/evaluator/builtin.go
@@ -15,7 +15,7 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-package builtin
+package evaluator
 
 import (
 	"github.com/juju/errors"
diff --git a/evaluator/builtin/control.go b/evaluator/builtin_control.go
similarity index 99%
rename from evaluator/builtin/control.go
rename to evaluator/builtin_control.go
index 81947bf7a0..c310f3fab6 100644
--- a/evaluator/builtin/control.go
+++ b/evaluator/builtin_control.go
@@ -11,7 +11,7 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-package builtin
+package evaluator
 
 import (
 	"github.com/pingcap/tidb/context"
diff --git a/evaluator/builtin/control_test.go b/evaluator/builtin_control_test.go
similarity index 90%
rename from evaluator/builtin/control_test.go
rename to evaluator/builtin_control_test.go
index e3b4bcdeb5..bf925d307e 100644
--- a/evaluator/builtin/control_test.go
+++ b/evaluator/builtin_control_test.go
@@ -11,7 +11,7 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-package builtin
+package evaluator
 
 import (
 	"errors"
@@ -19,7 +19,7 @@ import (
 	. "github.com/pingcap/check"
 )
 
-func (s *testBuiltinSuite) TestIf(c *C) {
+func (s *testEvaluatorSuite) TestIf(c *C) {
 	tbl := []struct {
 		Arg1 interface{}
 		Arg2 interface{}
@@ -41,7 +41,7 @@ func (s *testBuiltinSuite) TestIf(c *C) {
 	c.Assert(err, NotNil)
 }
 
-func (s *testBuiltinSuite) TestIfNull(c *C) {
+func (s *testEvaluatorSuite) TestIfNull(c *C) {
 	tbl := []struct {
 		Arg1 interface{}
 		Arg2 interface{}
@@ -59,7 +59,7 @@ func (s *testBuiltinSuite) TestIfNull(c *C) {
 	}
 }
 
-func (s *testBuiltinSuite) TestNullIf(c *C) {
+func (s *testEvaluatorSuite) TestNullIf(c *C) {
 	tbl := []struct {
 		Arg1 interface{}
 		Arg2 interface{}
diff --git a/evaluator/builtin/info.go b/evaluator/builtin_info.go
similarity index 99%
rename from evaluator/builtin/info.go
rename to evaluator/builtin_info.go
index f8af0bdaa1..2004c0d13c 100644
--- a/evaluator/builtin/info.go
+++ b/evaluator/builtin_info.go
@@ -15,7 +15,7 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-package builtin
+package evaluator
 
 import (
 	"github.com/juju/errors"
diff --git a/evaluator/builtin/info_test.go b/evaluator/builtin_info_test.go
similarity index 83%
rename from evaluator/builtin/info_test.go
rename to evaluator/builtin_info_test.go
index 6e66ea88d1..baa1c9e8ee 100644
--- a/evaluator/builtin/info_test.go
+++ b/evaluator/builtin_info_test.go
@@ -11,7 +11,7 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-package builtin
+package evaluator
 
 import (
 	. "github.com/pingcap/check"
@@ -21,12 +21,7 @@ import (
 	"github.com/pingcap/tidb/util/mock"
 )
 
-var _ = Suite(&testBuiltinInfoSuite{})
-
-type testBuiltinInfoSuite struct {
-}
-
-func (s *testBuiltinSuite) TestDatabase(c *C) {
+func (s *testEvaluatorSuite) TestDatabase(c *C) {
 	ctx := mock.NewContext()
 	v, err := builtinDatabase(nil, ctx)
 	c.Assert(err, IsNil)
@@ -38,7 +33,7 @@ func (s *testBuiltinSuite) TestDatabase(c *C) {
 	c.Assert(v, Equals, "test")
 }
 
-func (s *testBuiltinSuite) TestFoundRows(c *C) {
+func (s *testEvaluatorSuite) TestFoundRows(c *C) {
 	ctx := mock.NewContext()
 	v, err := builtinFoundRows(nil, ctx)
 	c.Assert(err, NotNil)
@@ -50,7 +45,7 @@ func (s *testBuiltinSuite) TestFoundRows(c *C) {
 	c.Assert(v, Equals, uint64(0))
 }
 
-func (s *testBuiltinSuite) TestUser(c *C) {
+func (s *testEvaluatorSuite) TestUser(c *C) {
 	ctx := mock.NewContext()
 	variable.BindSessionVars(ctx)
 	sessionVars := variable.GetSessionVars(ctx)
@@ -61,7 +56,7 @@ func (s *testBuiltinSuite) TestUser(c *C) {
 	c.Assert(v, Equals, "root@localhost")
 }
 
-func (s *testBuiltinSuite) TestCurrentUser(c *C) {
+func (s *testEvaluatorSuite) TestCurrentUser(c *C) {
 	ctx := mock.NewContext()
 	variable.BindSessionVars(ctx)
 	sessionVars := variable.GetSessionVars(ctx)
@@ -72,7 +67,7 @@ func (s *testBuiltinSuite) TestCurrentUser(c *C) {
 	c.Assert(v, Equals, "root@localhost")
 }
 
-func (s *testBuiltinSuite) TestConnectionID(c *C) {
+func (s *testEvaluatorSuite) TestConnectionID(c *C) {
 	ctx := mock.NewContext()
 	variable.BindSessionVars(ctx)
 	sessionVars := variable.GetSessionVars(ctx)
@@ -83,7 +78,7 @@ func (s *testBuiltinSuite) TestConnectionID(c *C) {
 	c.Assert(v, Equals, uint64(1))
 }
 
-func (s *testBuiltinSuite) TestVersion(c *C) {
+func (s *testEvaluatorSuite) TestVersion(c *C) {
 	ctx := mock.NewContext()
 	v, err := builtinVersion(nil, ctx)
 	c.Assert(err, IsNil)
diff --git a/evaluator/builtin/math.go b/evaluator/builtin_math.go
similarity index 99%
rename from evaluator/builtin/math.go
rename to evaluator/builtin_math.go
index 7e4e297395..c1d39e83b7 100644
--- a/evaluator/builtin/math.go
+++ b/evaluator/builtin_math.go
@@ -15,7 +15,7 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-package builtin
+package evaluator
 
 import (
 	"math"
diff --git a/evaluator/builtin/math_test.go b/evaluator/builtin_math_test.go
similarity index 91%
rename from evaluator/builtin/math_test.go
rename to evaluator/builtin_math_test.go
index 364c7ae491..844c300d54 100644
--- a/evaluator/builtin/math_test.go
+++ b/evaluator/builtin_math_test.go
@@ -11,13 +11,13 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-package builtin
+package evaluator
 
 import (
 	. "github.com/pingcap/check"
 )
 
-func (s *testBuiltinSuite) TestAbs(c *C) {
+func (s *testEvaluatorSuite) TestAbs(c *C) {
 	tbl := []struct {
 		Arg interface{}
 		Ret interface{}
@@ -37,14 +37,14 @@ func (s *testBuiltinSuite) TestAbs(c *C) {
 	}
 }
 
-func (s *testBuiltinSuite) TestRand(c *C) {
+func (s *testEvaluatorSuite) TestRand(c *C) {
 	v, err := builtinRand([]interface{}{}, nil)
 	c.Assert(err, IsNil)
 	c.Assert(v, Less, float64(1))
 	c.Assert(v, GreaterEqual, float64(0))
 }
 
-func (s *testBuiltinSuite) TestPow(c *C) {
+func (s *testEvaluatorSuite) TestPow(c *C) {
 	tbl := []struct {
 		Arg []interface{}
 		Ret float64
diff --git a/evaluator/builtin/string.go b/evaluator/builtin_string.go
similarity index 99%
rename from evaluator/builtin/string.go
rename to evaluator/builtin_string.go
index b4efdf5834..2431b5270a 100644
--- a/evaluator/builtin/string.go
+++ b/evaluator/builtin_string.go
@@ -15,7 +15,7 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-package builtin
+package evaluator
 
 import (
 	"fmt"
diff --git a/evaluator/builtin/string_test.go b/evaluator/builtin_string_test.go
similarity index 92%
rename from evaluator/builtin/string_test.go
rename to evaluator/builtin_string_test.go
index 204335d097..88469bde6b 100644
--- a/evaluator/builtin/string_test.go
+++ b/evaluator/builtin_string_test.go
@@ -11,7 +11,7 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-package builtin
+package evaluator
 
 import (
 	"errors"
@@ -22,7 +22,7 @@ import (
 	"github.com/pingcap/tidb/mysql"
 )
 
-func (s *testBuiltinSuite) TestLength(c *C) {
+func (s *testEvaluatorSuite) TestLength(c *C) {
 	v, err := builtinLength([]interface{}{nil}, nil)
 	c.Assert(err, IsNil)
 	c.Assert(v, IsNil)
@@ -47,7 +47,7 @@ func (s *testBuiltinSuite) TestLength(c *C) {
 	}
 }
 
-func (s *testBuiltinSuite) TestConcat(c *C) {
+func (s *testEvaluatorSuite) TestConcat(c *C) {
 	args := []interface{}{nil}
 
 	v, err := builtinConcat(args, nil)
@@ -69,7 +69,7 @@ func (s *testBuiltinSuite) TestConcat(c *C) {
 	c.Assert(err, NotNil)
 }
 
-func (s *testBuiltinSuite) TestConcatWS(c *C) {
+func (s *testEvaluatorSuite) TestConcatWS(c *C) {
 	args := []interface{}{nil}
 
 	v, err := builtinConcatWS(args, nil)
@@ -86,7 +86,7 @@ func (s *testBuiltinSuite) TestConcatWS(c *C) {
 	c.Assert(err, NotNil)
 }
 
-func (s *testBuiltinSuite) TestLeft(c *C) {
+func (s *testEvaluatorSuite) TestLeft(c *C) {
 	args := []interface{}{"abcdefg", int64(2)}
 	v, err := builtinLeft(args, nil)
 	c.Assert(err, IsNil)
@@ -111,7 +111,7 @@ func (s *testBuiltinSuite) TestLeft(c *C) {
 	c.Assert(err, NotNil)
 }
 
-func (s *testBuiltinSuite) TestRepeat(c *C) {
+func (s *testEvaluatorSuite) TestRepeat(c *C) {
 	args := []interface{}{"a", int64(2)}
 	v, err := builtinRepeat(args, nil)
 	c.Assert(err, IsNil)
@@ -138,7 +138,7 @@ func (s *testBuiltinSuite) TestRepeat(c *C) {
 	c.Assert(v, Equals, "")
 }
 
-func (s *testBuiltinSuite) TestLowerAndUpper(c *C) {
+func (s *testEvaluatorSuite) TestLowerAndUpper(c *C) {
 	v, err := builtinLower([]interface{}{nil}, nil)
 	c.Assert(err, IsNil)
 	c.Assert(v, IsNil)
@@ -167,7 +167,7 @@ func (s *testBuiltinSuite) TestLowerAndUpper(c *C) {
 	}
 }
 
-func (s *testBuiltinSuite) TestStrcmp(c *C) {
+func (s *testEvaluatorSuite) TestStrcmp(c *C) {
 	tbl := []struct {
 		Input  []interface{}
 		Expect interface{}
@@ -194,7 +194,7 @@ func (s *testBuiltinSuite) TestStrcmp(c *C) {
 	}
 }
 
-func (s *testBuiltinSuite) TestReplace(c *C) {
+func (s *testEvaluatorSuite) TestReplace(c *C) {
 	tbl := []struct {
 		Input  []interface{}
 		Expect interface{}
diff --git a/evaluator/builtin/builtin_test.go b/evaluator/builtin_test.go
similarity index 80%
rename from evaluator/builtin/builtin_test.go
rename to evaluator/builtin_test.go
index 498e2efb34..d63403039e 100644
--- a/evaluator/builtin/builtin_test.go
+++ b/evaluator/builtin_test.go
@@ -11,24 +11,13 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-package builtin
+package evaluator
 
 import (
-	"testing"
-
 	. "github.com/pingcap/check"
 )
 
-func TestT(t *testing.T) {
-	TestingT(t)
-}
-
-var _ = Suite(&testBuiltinSuite{})
-
-type testBuiltinSuite struct {
-}
-
-func (s *testBuiltinSuite) TestCoalesce(c *C) {
+func (s *testEvaluatorSuite) TestCoalesce(c *C) {
 	args := []interface{}{1, nil}
 	v, err := builtinCoalesce(args, nil)
 	c.Assert(err, IsNil)
diff --git a/evaluator/builtin/time.go b/evaluator/builtin_time.go
similarity index 99%
rename from evaluator/builtin/time.go
rename to evaluator/builtin_time.go
index 91e06f902d..e4112a7b47 100644
--- a/evaluator/builtin/time.go
+++ b/evaluator/builtin_time.go
@@ -15,7 +15,7 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-package builtin
+package evaluator
 
 import (
 	"time"
diff --git a/evaluator/builtin/time_test.go b/evaluator/builtin_time_test.go
similarity index 96%
rename from evaluator/builtin/time_test.go
rename to evaluator/builtin_time_test.go
index 49241e4f2d..9891ab7aec 100644
--- a/evaluator/builtin/time_test.go
+++ b/evaluator/builtin_time_test.go
@@ -11,7 +11,7 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-package builtin
+package evaluator
 
 import (
 	"strings"
@@ -21,7 +21,7 @@ import (
 	"github.com/pingcap/tidb/mysql"
 )
 
-func (s *testBuiltinSuite) TestDate(c *C) {
+func (s *testEvaluatorSuite) TestDate(c *C) {
 	tblDate := []struct {
 		Input  interface{}
 		Expect interface{}
@@ -167,7 +167,7 @@ func (s *testBuiltinSuite) TestDate(c *C) {
 	}
 }
 
-func (s *testBuiltinSuite) TestClock(c *C) {
+func (s *testEvaluatorSuite) TestClock(c *C) {
 	// test hour, minute, second, micro second
 
 	tbl := []struct {
@@ -237,7 +237,7 @@ func (s *testBuiltinSuite) TestClock(c *C) {
 	}
 }
 
-func (s *testBuiltinSuite) TestNow(c *C) {
+func (s *testEvaluatorSuite) TestNow(c *C) {
 	v, err := builtinNow(nil, nil)
 	c.Assert(err, IsNil)
 	t, ok := v.(mysql.Time)
@@ -259,7 +259,7 @@ func (s *testBuiltinSuite) TestNow(c *C) {
 	c.Assert(err, NotNil)
 }
 
-func (s *testBuiltinSuite) TestSysDate(c *C) {
+func (s *testEvaluatorSuite) TestSysDate(c *C) {
 	last := time.Now()
 	v, err := builtinSysDate(nil, nil)
 	c.Assert(err, IsNil)
@@ -277,7 +277,7 @@ func (s *testBuiltinSuite) TestSysDate(c *C) {
 	c.Assert(err, NotNil)
 }
 
-func (s *testBuiltinSuite) TestCurrentDate(c *C) {
+func (s *testEvaluatorSuite) TestCurrentDate(c *C) {
 	last := time.Now()
 	v, err := builtinCurrentDate(nil, nil)
 	c.Assert(err, IsNil)
@@ -286,7 +286,7 @@ func (s *testBuiltinSuite) TestCurrentDate(c *C) {
 	c.Assert(n.String(), GreaterEqual, last.Format(mysql.DateFormat))
 }
 
-func (s *testBuiltinSuite) TestCurrentTime(c *C) {
+func (s *testEvaluatorSuite) TestCurrentTime(c *C) {
 	tfStr := "15:04:05"
 
 	last := time.Now()
diff --git a/evaluator/evaluator.go b/evaluator/evaluator.go
index a7def07a2d..4e61203f62 100644
--- a/evaluator/evaluator.go
+++ b/evaluator/evaluator.go
@@ -21,7 +21,6 @@ import (
 	"github.com/juju/errors"
 	"github.com/pingcap/tidb/ast"
 	"github.com/pingcap/tidb/context"
-	"github.com/pingcap/tidb/evaluator/builtin"
 	"github.com/pingcap/tidb/mysql"
 	"github.com/pingcap/tidb/parser/opcode"
 	"github.com/pingcap/tidb/sessionctx/variable"
@@ -668,7 +667,7 @@ func (e *Evaluator) variable(v *ast.VariableExpr) bool {
 }
 
 func (e *Evaluator) funcCall(v *ast.FuncCallExpr) bool {
-	f, ok := builtin.Funcs[v.FnName.L]
+	f, ok := Funcs[v.FnName.L]
 	if !ok {
 		e.err = ErrInvalidOperation.Gen("unknown function %s", v.FnName.O)
 		return false