diff --git a/analysis.go b/analysis.go
index 6042c61..e3b6a9b 100644
--- a/analysis.go
+++ b/analysis.go
@@ -14,7 +14,8 @@ import (
 
 func Analysis(path string, analyzer *analysis.Analyzer) error {
 	packages, err := packages.Load(&packages.Config{
-		Mode: packages.LoadAllSyntax, // nolint:staticcheck
+		Mode:       packages.LoadAllSyntax, // nolint:staticcheck
+		BuildFlags: strings.Split(buildFlag, " "),
 	}, getAllPackageName(path)...)
 	if err != nil {
 		return err
diff --git a/analysis_callgraph.go b/analysis_callgraph.go
index 2990815..575b390 100644
--- a/analysis_callgraph.go
+++ b/analysis_callgraph.go
@@ -2,6 +2,7 @@ package main
 
 import (
 	"fmt"
+	"strings"
 
 	"golang.org/x/tools/go/callgraph"
 	"golang.org/x/tools/go/callgraph/cha"
@@ -15,8 +16,9 @@ import (
 
 func doCallgraph(algo string, tests bool, args []string) (*callgraph.Graph, *ssa.Program, error) {
 	cfg := &packages.Config{
-		Mode:  packages.LoadAllSyntax, // nolint:staticcheck
-		Tests: tests,
+		Mode:       packages.LoadAllSyntax, // nolint:staticcheck
+		Tests:      tests,
+		BuildFlags: strings.Split(buildFlag, " "),
 	}
 
 	initial, err := packages.Load(cfg, args...)
diff --git a/main.go b/main.go
index 1850a7b..900a8e0 100644
--- a/main.go
+++ b/main.go
@@ -7,9 +7,11 @@ import (
 )
 
 var path string
+var buildFlag string
 
 func main() {
 	flag.StringVar(&path, "path", ".", "package path")
+	flag.StringVar(&buildFlag, "buildflag", "--tags=", "build flag")
 	flag.Parse()
 
 	cg, prog, err := doCallgraph("vta", false, getAllPackageName(path))
diff --git a/test/test1.go b/test/test1.go
index f2c76de..cee170d 100644
--- a/test/test1.go
+++ b/test/test1.go
@@ -1,11 +1,15 @@
 package test
 
-// var m1 sync.Mutex // a
-// var a int
+import (
+	"fmt"
+	"sync"
+)
 
-// func f1() {
-// 	m1.Lock()
-// 	// defer m1.Unlock()
-// 	a++
-// 	fmt.Print(a)
-// }
+var m1 sync.Mutex // a1
+var a1 int
+
+func f1() {
+	m1.Lock()
+	// defer m1.Unlock()
+	fmt.Print(a1)
+}
diff --git a/test/test8.go b/test/test8.go
index 4827db5..76454b1 100644
--- a/test/test8.go
+++ b/test/test8.go
@@ -6,14 +6,14 @@ import (
 )
 
 type b struct {
-	*sync.Mutex // a
-	a           int
+	*sync.Mutex // a8
+	a8          int
 }
 
 func (b1 *b) f1() {
 	b1.Lock()
 	// defer b1.Unlock()
-	fmt.Print(b1.a)
+	fmt.Print(b1.a8)
 }
 
 func init() {
diff --git a/test/test9.go b/test/test9.go
new file mode 100644
index 0000000..2a6f5e1
--- /dev/null
+++ b/test/test9.go
@@ -0,0 +1,6 @@
+//go:build p1
+// +build p1
+
+package test
+
+func f() {}