diff --git a/chore/gentests/gentests.go b/chore/gentests/gentests.go
new file mode 100644
index 00000000..f839dfc8
--- /dev/null
+++ b/chore/gentests/gentests.go
@@ -0,0 +1,57 @@
+/*
+ * Copyright (c) 2024 The GoPlus Authors (goplus.org). All rights reserved.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package main
+
+import (
+	"fmt"
+	"os"
+	"strings"
+
+	"github.com/goplus/llgo/internal/llgen"
+	"github.com/goplus/mod"
+)
+
+func main() {
+	dir, _, err := mod.FindGoMod(".")
+	check(err)
+
+	llgen.Verbose = false
+
+	llgenDir(dir + "/cl/_testrt")
+	llgenDir(dir+"/cl/_testdata", "")
+}
+
+func llgenDir(dir string, pkgPath ...string) {
+	fis, err := os.ReadDir(dir)
+	check(err)
+	for _, fi := range fis {
+		name := fi.Name()
+		if !fi.IsDir() || strings.HasPrefix(name, "_") {
+			continue
+		}
+		testDir := dir + "/" + name
+		fmt.Fprintln(os.Stderr, "llgen", testDir)
+		os.Chdir(testDir)
+		llgen.SmartDoFile("in.go", pkgPath...)
+	}
+}
+
+func check(err error) {
+	if err != nil {
+		panic(err)
+	}
+}
diff --git a/chore/llgen/llgen.go b/chore/llgen/llgen.go
index 3473fa1d..ec27e29b 100644
--- a/chore/llgen/llgen.go
+++ b/chore/llgen/llgen.go
@@ -19,8 +19,6 @@ package main
 import (
 	"fmt"
 	"os"
-	"path/filepath"
-	"strings"
 
 	"github.com/goplus/llgo/internal/llgen"
 )
@@ -31,24 +29,6 @@ func main() {
 		return
 	}
 
-	inFile := os.Args[1]
-
-	dir, _ := filepath.Split(inFile)
-	fname := "llgo_autogen.ll"
-	if inCompilerDir(dir) {
-		fname = "out.ll"
-	}
-	outFile := dir + fname
-
 	llgen.Init()
-	if len(os.Args) >= 3 {
-		llgen.Do(os.Args[2], inFile, outFile)
-	} else {
-		llgen.DoFile(inFile, outFile)
-	}
-}
-
-func inCompilerDir(dir string) bool {
-	dir, _ = filepath.Abs(dir)
-	return strings.Contains(filepath.ToSlash(dir), "/llgo/cl/")
+	llgen.SmartDoFile(os.Args[1], os.Args[2:]...)
 }
diff --git a/cl/_testdata/fncall/out.ll b/cl/_testdata/fncall/out.ll
index 4adec91a..7b3c8d0b 100644
--- a/cl/_testdata/fncall/out.ll
+++ b/cl/_testdata/fncall/out.ll
@@ -18,6 +18,7 @@ _llgo_2:                                          ; preds = %_llgo_1, %_llgo_0
 
 define void @main() {
 _llgo_0:
+  call void @"github.com/goplus/llgo/internal/runtime.init"()
   call void @main.init()
   %0 = call i64 @main.max(i64 1, i64 2)
   ret void
@@ -34,3 +35,5 @@ _llgo_1:                                          ; preds = %_llgo_0
 _llgo_2:                                          ; preds = %_llgo_0
   ret i64 %1
 }
+
+declare void @"github.com/goplus/llgo/internal/runtime.init"()
diff --git a/cl/_testdata/importpkg/out.ll b/cl/_testdata/importpkg/out.ll
index 8aa4cbb1..6ee8cd05 100644
--- a/cl/_testdata/importpkg/out.ll
+++ b/cl/_testdata/importpkg/out.ll
@@ -27,6 +27,7 @@ _llgo_2:                                          ; preds = %_llgo_1, %_llgo_0
 
 define void @main() {
 _llgo_0:
+  call void @"github.com/goplus/llgo/internal/runtime.init"()
   call void @main.init()
   %0 = call i64 @"github.com/goplus/llgo/cl/internal/stdio.Max"(i64 2, i64 100)
   call void (ptr, ...) @printf(ptr @main.hello)
@@ -35,6 +36,8 @@ _llgo_0:
 
 declare void @"github.com/goplus/llgo/cl/internal/stdio.init"()
 
+declare void @"github.com/goplus/llgo/internal/runtime.init"()
+
 declare i64 @"github.com/goplus/llgo/cl/internal/stdio.Max"(i64, i64)
 
 declare void @printf(ptr, ...)
diff --git a/cl/_testdata/method/out.ll b/cl/_testdata/method/out.ll
index b4734045..3f7b91f5 100644
--- a/cl/_testdata/method/out.ll
+++ b/cl/_testdata/method/out.ll
@@ -42,6 +42,7 @@ _llgo_2:                                          ; preds = %_llgo_1, %_llgo_0
 
 define void @main() {
 _llgo_0:
+  call void @"github.com/goplus/llgo/internal/runtime.init"()
   call void @main.init()
   %0 = call i64 @"(main.T).Add"(i64 1, i64 2)
   call void (ptr, ...) @printf(ptr @main.format, i64 %0)
@@ -49,3 +50,5 @@ _llgo_0:
 }
 
 declare void @printf(ptr, ...)
+
+declare void @"github.com/goplus/llgo/internal/runtime.init"()
diff --git a/cl/_testdata/printf/out.ll b/cl/_testdata/printf/out.ll
index 65ac64ae..d2f6551e 100644
--- a/cl/_testdata/printf/out.ll
+++ b/cl/_testdata/printf/out.ll
@@ -26,9 +26,12 @@ _llgo_2:                                          ; preds = %_llgo_1, %_llgo_0
 
 define void @main() {
 _llgo_0:
+  call void @"github.com/goplus/llgo/internal/runtime.init"()
   call void @main.init()
   call void (ptr, ...) @printf(ptr @main.hello)
   ret void
 }
 
 declare void @printf(ptr, ...)
+
+declare void @"github.com/goplus/llgo/internal/runtime.init"()
diff --git a/cl/_testdata/printval/out.ll b/cl/_testdata/printval/out.ll
index e7fe3bd9..a27337a7 100644
--- a/cl/_testdata/printval/out.ll
+++ b/cl/_testdata/printval/out.ll
@@ -29,9 +29,12 @@ _llgo_2:                                          ; preds = %_llgo_1, %_llgo_0
 
 define void @main() {
 _llgo_0:
+  call void @"github.com/goplus/llgo/internal/runtime.init"()
   call void @main.init()
   call void (ptr, ...) @printf(ptr @main.format, i64 100)
   ret void
 }
 
 declare void @printf(ptr, ...)
+
+declare void @"github.com/goplus/llgo/internal/runtime.init"()
diff --git a/cl/_testdata/ptrmthd/out.ll b/cl/_testdata/ptrmthd/out.ll
index 25fe6d7a..18f6bc04 100644
--- a/cl/_testdata/ptrmthd/out.ll
+++ b/cl/_testdata/ptrmthd/out.ll
@@ -35,9 +35,12 @@ _llgo_2:                                          ; preds = %_llgo_1, %_llgo_0
 
 define void @main() {
 _llgo_0:
+  call void @"github.com/goplus/llgo/internal/runtime.init"()
   call void @main.init()
   call void @"(*main.T).Print"(ptr @main.format, i64 100)
   ret void
 }
 
 declare void @printf(ptr, ...)
+
+declare void @"github.com/goplus/llgo/internal/runtime.init"()
diff --git a/cl/_testdata/untyped/out.ll b/cl/_testdata/untyped/out.ll
index fd8b4d8e..eb1cb11c 100644
--- a/cl/_testdata/untyped/out.ll
+++ b/cl/_testdata/untyped/out.ll
@@ -20,6 +20,7 @@ _llgo_2:                                          ; preds = %_llgo_1, %_llgo_0
 
 define void @main() {
 _llgo_0:
+  call void @"github.com/goplus/llgo/internal/runtime.init"()
   call void @main.init()
   br i1 false, label %_llgo_1, label %_llgo_2
 
@@ -30,3 +31,5 @@ _llgo_1:                                          ; preds = %_llgo_0
 _llgo_2:                                          ; preds = %_llgo_1, %_llgo_0
   ret void
 }
+
+declare void @"github.com/goplus/llgo/internal/runtime.init"()
diff --git a/cl/_testdata/varinit/out.ll b/cl/_testdata/varinit/out.ll
index 9aebe715..d631ebc5 100644
--- a/cl/_testdata/varinit/out.ll
+++ b/cl/_testdata/varinit/out.ll
@@ -20,6 +20,7 @@ _llgo_2:                                          ; preds = %_llgo_1, %_llgo_0
 
 define void @main() {
 _llgo_0:
+  call void @"github.com/goplus/llgo/internal/runtime.init"()
   call void @main.init()
   %0 = load i64, ptr @main.a, align 4
   %1 = add i64 %0, 1
@@ -27,3 +28,5 @@ _llgo_0:
   %2 = load i64, ptr @main.a, align 4
   ret void
 }
+
+declare void @"github.com/goplus/llgo/internal/runtime.init"()
diff --git a/cl/_testrt/alloca/out.ll b/cl/_testrt/alloca/out.ll
index 3a0f3101..f7c596ee 100644
--- a/cl/_testrt/alloca/out.ll
+++ b/cl/_testrt/alloca/out.ll
@@ -20,6 +20,7 @@ _llgo_2:                                          ; preds = %_llgo_1, %_llgo_0
 
 define void @main() {
 _llgo_0:
+  call void @"github.com/goplus/llgo/internal/runtime.init"()
   call void @main.init()
   %0 = alloca i8, i64 4, align 1
   %1 = call ptr @memcpy(ptr %0, ptr @0, i64 4)
@@ -27,6 +28,8 @@ _llgo_0:
   ret void
 }
 
+declare void @"github.com/goplus/llgo/internal/runtime.init"()
+
 declare ptr @memcpy(ptr, ptr, i64)
 
 declare i32 @printf(ptr, ...)
diff --git a/cl/_testrt/allocstr/out.ll b/cl/_testrt/allocstr/out.ll
index 5a3a68b3..8713016e 100644
--- a/cl/_testrt/allocstr/out.ll
+++ b/cl/_testrt/allocstr/out.ll
@@ -28,6 +28,7 @@ _llgo_2:                                          ; preds = %_llgo_1, %_llgo_0
 
 define void @main() {
 _llgo_0:
+  call void @"github.com/goplus/llgo/internal/runtime.init"()
   call void @main.init()
   %0 = call %"github.com/goplus/llgo/internal/runtime.String" @main.hello()
   %1 = call i64 @"github.com/goplus/llgo/internal/runtime.StringLen"(%"github.com/goplus/llgo/internal/runtime.String" %0)
@@ -40,6 +41,8 @@ _llgo_0:
 
 declare %"github.com/goplus/llgo/internal/runtime.String" @"github.com/goplus/llgo/internal/runtime.NewString"(ptr, i64)
 
+declare void @"github.com/goplus/llgo/internal/runtime.init"()
+
 declare i64 @"github.com/goplus/llgo/internal/runtime.StringLen"(%"github.com/goplus/llgo/internal/runtime.Slice")
 
 declare ptr @"github.com/goplus/llgo/internal/runtime.CStrCopy"(ptr, %"github.com/goplus/llgo/internal/runtime.String")
diff --git a/cl/_testrt/any/out.ll b/cl/_testrt/any/out.ll
index cb4e49d9..3824cf96 100644
--- a/cl/_testrt/any/out.ll
+++ b/cl/_testrt/any/out.ll
@@ -29,6 +29,7 @@ _llgo_2:                                          ; preds = %_llgo_1, %_llgo_0
 
 define void @main() {
 _llgo_0:
+  call void @"github.com/goplus/llgo/internal/runtime.init"()
   call void @main.init()
   %0 = call ptr @"github.com/goplus/llgo/internal/runtime.Basic"(i64 2)
   %1 = call %"github.com/goplus/llgo/internal/runtime.iface" @"github.com/goplus/llgo/internal/runtime.MakeAnyInt"(ptr %0, i64 100)
@@ -41,6 +42,8 @@ declare i64 @"github.com/goplus/llgo/internal/runtime.I2Int"(%"github.com/goplus
 
 declare ptr @"github.com/goplus/llgo/internal/runtime.Basic"(i64)
 
+declare void @"github.com/goplus/llgo/internal/runtime.init"()
+
 declare %"github.com/goplus/llgo/internal/runtime.iface" @"github.com/goplus/llgo/internal/runtime.MakeAnyInt"(ptr, i64)
 
 declare i32 @printf(ptr, ...)
diff --git a/cl/_testrt/builtin/out.ll b/cl/_testrt/builtin/out.ll
index 7588a13e..ee999eb5 100644
--- a/cl/_testrt/builtin/out.ll
+++ b/cl/_testrt/builtin/out.ll
@@ -26,6 +26,7 @@ _llgo_2:                                          ; preds = %_llgo_1, %_llgo_0
 
 define void @main() {
 _llgo_0:
+  call void @"github.com/goplus/llgo/internal/runtime.init"()
   call void @main.init()
   %0 = call ptr @"github.com/goplus/llgo/internal/runtime.Alloc"(i64 16)
   %1 = getelementptr inbounds i64, ptr %0, i64 0
@@ -52,6 +53,8 @@ _llgo_0:
   ret void
 }
 
+declare void @"github.com/goplus/llgo/internal/runtime.init"()
+
 declare ptr @"github.com/goplus/llgo/internal/runtime.Alloc"(i64)
 
 declare %"github.com/goplus/llgo/internal/runtime.Slice" @"github.com/goplus/llgo/internal/runtime.NewSlice"(ptr, i64, i64)
diff --git a/cl/_testrt/cstr/out.ll b/cl/_testrt/cstr/out.ll
index f7b5d255..969ca268 100644
--- a/cl/_testrt/cstr/out.ll
+++ b/cl/_testrt/cstr/out.ll
@@ -19,9 +19,12 @@ _llgo_2:                                          ; preds = %_llgo_1, %_llgo_0
 
 define void @main() {
 _llgo_0:
+  call void @"github.com/goplus/llgo/internal/runtime.init"()
   call void @main.init()
   call void (ptr, ...) @printf(ptr @0)
   ret void
 }
 
 declare void @printf(ptr, ...)
+
+declare void @"github.com/goplus/llgo/internal/runtime.init"()
diff --git a/cl/_testrt/hello/out.ll b/cl/_testrt/hello/out.ll
index c8e0b5f1..4f920ffa 100644
--- a/cl/_testrt/hello/out.ll
+++ b/cl/_testrt/hello/out.ll
@@ -29,12 +29,15 @@ _llgo_2:                                          ; preds = %_llgo_1, %_llgo_0
 
 define void @main() {
 _llgo_0:
+  call void @"github.com/goplus/llgo/internal/runtime.init"()
   call void @main.init()
   %0 = call i32 @strlen(ptr @main.format)
   call void (ptr, ...) @printf(ptr @main.format, i32 %0)
   ret void
 }
 
+declare void @"github.com/goplus/llgo/internal/runtime.init"()
+
 declare i32 @strlen(ptr)
 
 declare void @printf(ptr, ...)
diff --git a/cl/_testrt/map/out.ll b/cl/_testrt/map/out.ll
index 1cfe17c1..7f1f90f0 100644
--- a/cl/_testrt/map/out.ll
+++ b/cl/_testrt/map/out.ll
@@ -18,9 +18,12 @@ _llgo_2:                                          ; preds = %_llgo_1, %_llgo_0
 
 define void @main() {
 _llgo_0:
+  call void @"github.com/goplus/llgo/internal/runtime.init"()
   call void @main.init()
   %0 = call ptr @"github.com/goplus/llgo/internal/runtime.MakeSmallMap"()
   ret void
 }
 
+declare void @"github.com/goplus/llgo/internal/runtime.init"()
+
 declare ptr @"github.com/goplus/llgo/internal/runtime.MakeSmallMap"()
diff --git a/cl/_testrt/panic/in.go b/cl/_testrt/panic/in.go
new file mode 100644
index 00000000..d9411234
--- /dev/null
+++ b/cl/_testrt/panic/in.go
@@ -0,0 +1,5 @@
+package main
+
+func main() {
+	panic("panic message")
+}
diff --git a/cl/_testrt/panic/out.ll b/cl/_testrt/panic/out.ll
new file mode 100644
index 00000000..155cfb20
--- /dev/null
+++ b/cl/_testrt/panic/out.ll
@@ -0,0 +1,39 @@
+; ModuleID = 'main'
+source_filename = "main"
+
+%"github.com/goplus/llgo/internal/runtime.String" = type { ptr, i64 }
+%"github.com/goplus/llgo/internal/runtime.iface" = type { ptr, ptr }
+
+@"main.init$guard" = global ptr null
+@0 = private unnamed_addr constant [14 x i8] c"panic message\00", align 1
+
+define void @main.init() {
+_llgo_0:
+  %0 = load i1, ptr @"main.init$guard", align 1
+  br i1 %0, label %_llgo_2, label %_llgo_1
+
+_llgo_1:                                          ; preds = %_llgo_0
+  store i1 true, ptr @"main.init$guard", align 1
+  br label %_llgo_2
+
+_llgo_2:                                          ; preds = %_llgo_1, %_llgo_0
+  ret void
+}
+
+define void @main() {
+_llgo_0:
+  call void @"github.com/goplus/llgo/internal/runtime.init"()
+  call void @main.init()
+  %0 = call %"github.com/goplus/llgo/internal/runtime.String" @"github.com/goplus/llgo/internal/runtime.NewString"(ptr @0, i64 13)
+  %1 = call %"github.com/goplus/llgo/internal/runtime.iface" @"github.com/goplus/llgo/internal/runtime.MakeAnyString"(%"github.com/goplus/llgo/internal/runtime.String" %0)
+  call void @"github.com/goplus/llgo/internal/runtime.TracePanic"(%"github.com/goplus/llgo/internal/runtime.iface" %1)
+  unreachable
+}
+
+declare void @"github.com/goplus/llgo/internal/runtime.init"()
+
+declare %"github.com/goplus/llgo/internal/runtime.String" @"github.com/goplus/llgo/internal/runtime.NewString"(ptr, i64)
+
+declare %"github.com/goplus/llgo/internal/runtime.iface" @"github.com/goplus/llgo/internal/runtime.MakeAnyString"(%"github.com/goplus/llgo/internal/runtime.String")
+
+declare void @"github.com/goplus/llgo/internal/runtime.TracePanic"(%"github.com/goplus/llgo/internal/runtime.iface")
diff --git a/cl/_testrt/strlen/out.ll b/cl/_testrt/strlen/out.ll
index 130d120f..a3aab0c6 100644
--- a/cl/_testrt/strlen/out.ll
+++ b/cl/_testrt/strlen/out.ll
@@ -29,6 +29,7 @@ _llgo_2:                                          ; preds = %_llgo_1, %_llgo_0
 
 define void @main() {
 _llgo_0:
+  call void @"github.com/goplus/llgo/internal/runtime.init"()
   call void @main.init()
   %0 = call i32 @strlen(ptr @main.format)
   call void (ptr, ...) @printf(ptr @main.format, i32 %0)
@@ -38,3 +39,5 @@ _llgo_0:
 declare void @printf(ptr, ...)
 
 declare i32 @strlen(ptr)
+
+declare void @"github.com/goplus/llgo/internal/runtime.init"()
diff --git a/cl/_testrt/struct/out.ll b/cl/_testrt/struct/out.ll
index a8e29724..adead9a3 100644
--- a/cl/_testrt/struct/out.ll
+++ b/cl/_testrt/struct/out.ll
@@ -56,6 +56,7 @@ _llgo_2:                                          ; preds = %_llgo_1, %_llgo_0
 
 define void @main() {
 _llgo_0:
+  call void @"github.com/goplus/llgo/internal/runtime.init"()
   call void @main.init()
   %0 = alloca %main.Foo, align 8
   %1 = getelementptr inbounds %main.Foo, ptr %0, i32 0, i32 0
@@ -68,3 +69,5 @@ _llgo_0:
 }
 
 declare void @printf(ptr, ...)
+
+declare void @"github.com/goplus/llgo/internal/runtime.init"()
diff --git a/cl/_testrt/sum/out.ll b/cl/_testrt/sum/out.ll
index 10750baf..1b390114 100644
--- a/cl/_testrt/sum/out.ll
+++ b/cl/_testrt/sum/out.ll
@@ -21,6 +21,7 @@ _llgo_2:                                          ; preds = %_llgo_1, %_llgo_0
 
 define void @main() {
 _llgo_0:
+  call void @"github.com/goplus/llgo/internal/runtime.init"()
   call void @main.init()
   %0 = call ptr @"github.com/goplus/llgo/internal/runtime.Alloc"(i64 16)
   %1 = getelementptr inbounds i64, ptr %0, i64 0
@@ -60,6 +61,8 @@ _llgo_3:                                          ; preds = %_llgo_1
   ret i64 %2
 }
 
+declare void @"github.com/goplus/llgo/internal/runtime.init"()
+
 declare ptr @"github.com/goplus/llgo/internal/runtime.Alloc"(i64)
 
 declare %"github.com/goplus/llgo/internal/runtime.Slice" @"github.com/goplus/llgo/internal/runtime.NewSlice"(ptr, i64, i64)
diff --git a/cl/_testrt/typalias/out.ll b/cl/_testrt/typalias/out.ll
index 3e2d16f8..d902282b 100644
--- a/cl/_testrt/typalias/out.ll
+++ b/cl/_testrt/typalias/out.ll
@@ -45,6 +45,7 @@ _llgo_2:                                          ; preds = %_llgo_1, %_llgo_0
 
 define void @main() {
 _llgo_0:
+  call void @"github.com/goplus/llgo/internal/runtime.init"()
   call void @main.init()
   %0 = call ptr @"github.com/goplus/llgo/internal/runtime.Alloc"(i64 16)
   %1 = getelementptr inbounds { i32, i1 }, ptr %0, i32 0, i32 0
@@ -57,4 +58,6 @@ _llgo_0:
 
 declare void @printf(ptr, ...)
 
+declare void @"github.com/goplus/llgo/internal/runtime.init"()
+
 declare ptr @"github.com/goplus/llgo/internal/runtime.Alloc"(i64)
diff --git a/cl/_testrt/unreachable/out.ll b/cl/_testrt/unreachable/out.ll
index 1692ce52..c8127892 100644
--- a/cl/_testrt/unreachable/out.ll
+++ b/cl/_testrt/unreachable/out.ll
@@ -25,10 +25,13 @@ _llgo_2:                                          ; preds = %_llgo_1, %_llgo_0
 
 define void @main() {
 _llgo_0:
+  call void @"github.com/goplus/llgo/internal/runtime.init"()
   call void @main.init()
   call void @main.foo()
   %0 = call i32 (ptr, ...) @printf(ptr @0)
   ret void
 }
 
+declare void @"github.com/goplus/llgo/internal/runtime.init"()
+
 declare i32 @printf(ptr, ...)
diff --git a/cl/compile.go b/cl/compile.go
index 1bf1f593..c70c59c6 100644
--- a/cl/compile.go
+++ b/cl/compile.go
@@ -231,8 +231,9 @@ func (p *context) compileBlock(b llssa.Builder, block *ssa.BasicBlock, doInit bo
 	ret := p.fn.Block(block.Index)
 	b.SetBlock(ret)
 	if doInit {
-		fn := p.pkg.FuncOf("main.init")
-		b.Call(fn.Expr)
+		pkg := p.pkg
+		callRuntimeInit(b, pkg)
+		b.Call(pkg.FuncOf("main.init").Expr)
 	}
 	for _, instr := range block.Instrs {
 		p.compileInstr(b, instr)
@@ -240,6 +241,15 @@ func (p *context) compileBlock(b llssa.Builder, block *ssa.BasicBlock, doInit bo
 	return ret
 }
 
+const (
+	RuntimeInit = llssa.PkgRuntime + ".init"
+)
+
+func callRuntimeInit(b llssa.Builder, pkg llssa.Package) {
+	fn := pkg.NewFunc(RuntimeInit, types.NewSignatureType(nil, nil, nil, nil, nil, false))
+	b.Call(fn.Expr)
+}
+
 func isAny(t types.Type) bool {
 	if t, ok := t.(*types.Interface); ok {
 		return t.Empty()
diff --git a/internal/llgen/llgen.go b/internal/llgen/llgen.go
index f33a007b..d56b809e 100644
--- a/internal/llgen/llgen.go
+++ b/internal/llgen/llgen.go
@@ -66,7 +66,9 @@ func Gen(pkgPath, inFile string, src any) string {
 		&types.Config{Importer: imp}, fset, pkg, files, ssa.SanityCheckFunctions)
 	check(err)
 
-	ssaPkg.WriteTo(os.Stderr)
+	if Verbose {
+		ssaPkg.WriteTo(os.Stderr)
+	}
 
 	prog := llssa.NewProgram(nil)
 	ret, err := cl.NewPackage(prog, ssaPkg, files)
@@ -80,3 +82,7 @@ func check(err error) {
 		panic(err)
 	}
 }
+
+var (
+	Verbose = true
+)
diff --git a/internal/llgen/llgenf.go b/internal/llgen/llgenf.go
index 16990ae7..046910e5 100644
--- a/internal/llgen/llgenf.go
+++ b/internal/llgen/llgenf.go
@@ -19,6 +19,8 @@ package llgen
 import (
 	"go/types"
 	"os"
+	"path/filepath"
+	"strings"
 
 	"github.com/goplus/llgo/cl"
 	"golang.org/x/tools/go/packages"
@@ -66,3 +68,23 @@ func DoFile(fileOrPkg, outFile string) {
 	err := os.WriteFile(outFile, []byte(ret), 0644)
 	check(err)
 }
+
+func SmartDoFile(inFile string, pkgPath ...string) {
+	dir, _ := filepath.Split(inFile)
+	fname := "llgo_autogen.ll"
+	if inCompilerDir(dir) {
+		fname = "out.ll"
+	}
+	outFile := dir + fname
+
+	if len(pkgPath) > 0 {
+		Do(pkgPath[0], inFile, outFile)
+	} else {
+		DoFile(inFile, outFile)
+	}
+}
+
+func inCompilerDir(dir string) bool {
+	dir, _ = filepath.Abs(dir)
+	return strings.Contains(filepath.ToSlash(dir), "/llgo/cl/")
+}
diff --git a/internal/runtime/llgo_autogen.ll b/internal/runtime/llgo_autogen.ll
index dfd13bdd..4af3bc58 100644
--- a/internal/runtime/llgo_autogen.ll
+++ b/internal/runtime/llgo_autogen.ll
@@ -13,6 +13,9 @@ source_filename = "github.com/goplus/llgo/internal/runtime"
 @"github.com/goplus/llgo/internal/runtime.init$guard" = global ptr null
 @"github.com/goplus/llgo/internal/runtime.sizeBasicTypes" = global ptr null
 @0 = private unnamed_addr constant [21 x i8] c"I2Int: type mismatch\00", align 1
+@1 = private unnamed_addr constant [19 x i8] c"MakeAnyString(%p)\0A\00", align 1
+@2 = private unnamed_addr constant [11 x i8] c"Panic(%p)\0A\00", align 1
+@3 = private unnamed_addr constant [11 x i8] c"panic: %s\0A\00", align 1
 
 define ptr @"github.com/goplus/llgo/internal/runtime.Alloc"(i64 %0) {
 _llgo_0:
@@ -108,51 +111,52 @@ _llgo_1:                                          ; preds = %_llgo_0
 _llgo_2:                                          ; preds = %_llgo_0
   %11 = call %"github.com/goplus/llgo/internal/runtime.String" @"github.com/goplus/llgo/internal/runtime.NewString"(ptr @0, i64 20)
   %12 = call %"github.com/goplus/llgo/internal/runtime.iface" @"github.com/goplus/llgo/internal/runtime.MakeAnyString"(%"github.com/goplus/llgo/internal/runtime.String" %11)
+  call void @"github.com/goplus/llgo/internal/runtime.TracePanic"(%"github.com/goplus/llgo/internal/runtime.iface" %12)
   unreachable
 }
 
 define %"github.com/goplus/llgo/internal/runtime.iface" @"github.com/goplus/llgo/internal/runtime.MakeAny"(ptr %0, ptr %1) {
 _llgo_0:
-  %2 = alloca %"github.com/goplus/llgo/internal/runtime.iface", align 8
-  %3 = getelementptr inbounds %"github.com/goplus/llgo/internal/runtime.iface", ptr %2, i32 0, i32 0
-  %4 = call ptr @"github.com/goplus/llgo/internal/runtime.Alloc"(i64 16)
-  %5 = getelementptr inbounds %"github.com/goplus/llgo/internal/runtime.itab", ptr %4, i32 0, i32 0
-  %6 = load ptr, ptr @"github.com/goplus/llgo/internal/runtime.TyAny", align 8
-  %7 = getelementptr inbounds %"github.com/goplus/llgo/internal/runtime.itab", ptr %4, i32 0, i32 1
-  %8 = getelementptr inbounds %"github.com/goplus/llgo/internal/runtime.itab", ptr %4, i32 0, i32 2
-  %9 = getelementptr inbounds %"github.com/goplus/llgo/internal/runtime.itab", ptr %4, i32 0, i32 4
-  %10 = getelementptr inbounds i64, ptr %9, i64 0
-  store ptr %6, ptr %5, align 8
-  store ptr %0, ptr %7, align 8
-  store i32 0, ptr %8, align 4
-  store i64 0, ptr %10, align 4
-  %11 = getelementptr inbounds %"github.com/goplus/llgo/internal/runtime.iface", ptr %2, i32 0, i32 1
+  %2 = call ptr @"github.com/goplus/llgo/internal/runtime.Alloc"(i64 16)
+  %3 = getelementptr inbounds %"github.com/goplus/llgo/internal/runtime.itab", ptr %2, i32 0, i32 0
+  %4 = load ptr, ptr @"github.com/goplus/llgo/internal/runtime.TyAny", align 8
+  %5 = getelementptr inbounds %"github.com/goplus/llgo/internal/runtime.itab", ptr %2, i32 0, i32 1
+  %6 = getelementptr inbounds %"github.com/goplus/llgo/internal/runtime.itab", ptr %2, i32 0, i32 2
+  %7 = getelementptr inbounds %"github.com/goplus/llgo/internal/runtime.itab", ptr %2, i32 0, i32 4
+  %8 = getelementptr inbounds i64, ptr %7, i64 0
   store ptr %4, ptr %3, align 8
+  store ptr %0, ptr %5, align 8
+  store i32 0, ptr %6, align 4
+  store i64 0, ptr %8, align 4
+  %9 = alloca %"github.com/goplus/llgo/internal/runtime.iface", align 8
+  %10 = getelementptr inbounds %"github.com/goplus/llgo/internal/runtime.iface", ptr %9, i32 0, i32 0
+  %11 = getelementptr inbounds %"github.com/goplus/llgo/internal/runtime.iface", ptr %9, i32 0, i32 1
+  store ptr %2, ptr %10, align 8
   store ptr %1, ptr %11, align 8
-  %12 = load %"github.com/goplus/llgo/internal/runtime.iface", ptr %2, align 8
+  %12 = load %"github.com/goplus/llgo/internal/runtime.iface", ptr %9, align 8
   ret %"github.com/goplus/llgo/internal/runtime.iface" %12
 }
 
 define %"github.com/goplus/llgo/internal/runtime.iface" @"github.com/goplus/llgo/internal/runtime.MakeAnyInt"(ptr %0, i64 %1) {
 _llgo_0:
-  %2 = alloca %"github.com/goplus/llgo/internal/runtime.iface", align 8
-  %3 = getelementptr inbounds %"github.com/goplus/llgo/internal/runtime.iface", ptr %2, i32 0, i32 0
-  %4 = call ptr @"github.com/goplus/llgo/internal/runtime.Alloc"(i64 16)
-  %5 = getelementptr inbounds %"github.com/goplus/llgo/internal/runtime.itab", ptr %4, i32 0, i32 0
-  %6 = load ptr, ptr @"github.com/goplus/llgo/internal/runtime.TyAny", align 8
-  %7 = getelementptr inbounds %"github.com/goplus/llgo/internal/runtime.itab", ptr %4, i32 0, i32 1
-  %8 = getelementptr inbounds %"github.com/goplus/llgo/internal/runtime.itab", ptr %4, i32 0, i32 2
-  %9 = getelementptr inbounds %"github.com/goplus/llgo/internal/runtime.itab", ptr %4, i32 0, i32 4
-  %10 = getelementptr inbounds i64, ptr %9, i64 0
-  store ptr %6, ptr %5, align 8
-  store ptr %0, ptr %7, align 8
-  store i32 0, ptr %8, align 4
-  store i64 0, ptr %10, align 4
-  %11 = getelementptr inbounds %"github.com/goplus/llgo/internal/runtime.iface", ptr %2, i32 0, i32 1
-  %12 = inttoptr i64 %1 to ptr
+  %2 = call ptr @"github.com/goplus/llgo/internal/runtime.Alloc"(i64 16)
+  %3 = getelementptr inbounds %"github.com/goplus/llgo/internal/runtime.itab", ptr %2, i32 0, i32 0
+  %4 = load ptr, ptr @"github.com/goplus/llgo/internal/runtime.TyAny", align 8
+  %5 = getelementptr inbounds %"github.com/goplus/llgo/internal/runtime.itab", ptr %2, i32 0, i32 1
+  %6 = getelementptr inbounds %"github.com/goplus/llgo/internal/runtime.itab", ptr %2, i32 0, i32 2
+  %7 = getelementptr inbounds %"github.com/goplus/llgo/internal/runtime.itab", ptr %2, i32 0, i32 4
+  %8 = getelementptr inbounds i64, ptr %7, i64 0
   store ptr %4, ptr %3, align 8
+  store ptr %0, ptr %5, align 8
+  store i32 0, ptr %6, align 4
+  store i64 0, ptr %8, align 4
+  %9 = alloca %"github.com/goplus/llgo/internal/runtime.iface", align 8
+  %10 = getelementptr inbounds %"github.com/goplus/llgo/internal/runtime.iface", ptr %9, i32 0, i32 0
+  %11 = getelementptr inbounds %"github.com/goplus/llgo/internal/runtime.iface", ptr %9, i32 0, i32 1
+  %12 = inttoptr i64 %1 to ptr
+  store ptr %2, ptr %10, align 8
   store ptr %12, ptr %11, align 8
-  %13 = load %"github.com/goplus/llgo/internal/runtime.iface", ptr %2, align 8
+  %13 = load %"github.com/goplus/llgo/internal/runtime.iface", ptr %9, align 8
   ret %"github.com/goplus/llgo/internal/runtime.iface" %13
 }
 
@@ -160,45 +164,46 @@ define %"github.com/goplus/llgo/internal/runtime.iface" @"github.com/goplus/llgo
 _llgo_0:
   %1 = call ptr @"github.com/goplus/llgo/internal/runtime.Alloc"(i64 16)
   store %"github.com/goplus/llgo/internal/runtime.String" %0, ptr %1, align 8
-  %2 = alloca %"github.com/goplus/llgo/internal/runtime.iface", align 8
-  %3 = getelementptr inbounds %"github.com/goplus/llgo/internal/runtime.iface", ptr %2, i32 0, i32 0
-  %4 = call ptr @"github.com/goplus/llgo/internal/runtime.Alloc"(i64 16)
-  %5 = getelementptr inbounds %"github.com/goplus/llgo/internal/runtime.itab", ptr %4, i32 0, i32 0
-  %6 = load ptr, ptr @"github.com/goplus/llgo/internal/runtime.TyAny", align 8
-  %7 = getelementptr inbounds %"github.com/goplus/llgo/internal/runtime.itab", ptr %4, i32 0, i32 1
-  %8 = call ptr @"github.com/goplus/llgo/internal/runtime.Basic"(i64 24)
-  %9 = getelementptr inbounds %"github.com/goplus/llgo/internal/runtime.itab", ptr %4, i32 0, i32 2
-  %10 = getelementptr inbounds %"github.com/goplus/llgo/internal/runtime.itab", ptr %4, i32 0, i32 4
-  %11 = getelementptr inbounds i64, ptr %10, i64 0
-  store ptr %6, ptr %5, align 8
-  store ptr %8, ptr %7, align 8
-  store i32 0, ptr %9, align 4
-  store i64 0, ptr %11, align 4
-  %12 = getelementptr inbounds %"github.com/goplus/llgo/internal/runtime.iface", ptr %2, i32 0, i32 1
-  store ptr %4, ptr %3, align 8
-  store ptr %1, ptr %12, align 8
-  %13 = load %"github.com/goplus/llgo/internal/runtime.iface", ptr %2, align 8
-  ret %"github.com/goplus/llgo/internal/runtime.iface" %13
+  %2 = call ptr @"github.com/goplus/llgo/internal/runtime.Basic"(i64 24)
+  %3 = call ptr @"github.com/goplus/llgo/internal/runtime.Alloc"(i64 16)
+  %4 = getelementptr inbounds %"github.com/goplus/llgo/internal/runtime.itab", ptr %3, i32 0, i32 0
+  %5 = load ptr, ptr @"github.com/goplus/llgo/internal/runtime.TyAny", align 8
+  %6 = getelementptr inbounds %"github.com/goplus/llgo/internal/runtime.itab", ptr %3, i32 0, i32 1
+  %7 = getelementptr inbounds %"github.com/goplus/llgo/internal/runtime.itab", ptr %3, i32 0, i32 2
+  %8 = getelementptr inbounds %"github.com/goplus/llgo/internal/runtime.itab", ptr %3, i32 0, i32 4
+  %9 = getelementptr inbounds i64, ptr %8, i64 0
+  store ptr %5, ptr %4, align 8
+  store ptr %2, ptr %6, align 8
+  store i32 0, ptr %7, align 4
+  store i64 0, ptr %9, align 4
+  %10 = call i32 (ptr, ...) @printf(ptr @1, ptr %2)
+  %11 = alloca %"github.com/goplus/llgo/internal/runtime.iface", align 8
+  %12 = getelementptr inbounds %"github.com/goplus/llgo/internal/runtime.iface", ptr %11, i32 0, i32 0
+  %13 = getelementptr inbounds %"github.com/goplus/llgo/internal/runtime.iface", ptr %11, i32 0, i32 1
+  store ptr %3, ptr %12, align 8
+  store ptr %1, ptr %13, align 8
+  %14 = load %"github.com/goplus/llgo/internal/runtime.iface", ptr %11, align 8
+  ret %"github.com/goplus/llgo/internal/runtime.iface" %14
 }
 
 define %"github.com/goplus/llgo/internal/runtime.iface" @"github.com/goplus/llgo/internal/runtime.MakeInterface"(ptr %0, ptr %1, ptr %2) {
 _llgo_0:
-  %3 = alloca %"github.com/goplus/llgo/internal/runtime.iface", align 8
-  %4 = getelementptr inbounds %"github.com/goplus/llgo/internal/runtime.iface", ptr %3, i32 0, i32 0
-  %5 = call ptr @"github.com/goplus/llgo/internal/runtime.Alloc"(i64 16)
-  %6 = getelementptr inbounds %"github.com/goplus/llgo/internal/runtime.itab", ptr %5, i32 0, i32 0
-  %7 = getelementptr inbounds %"github.com/goplus/llgo/internal/runtime.itab", ptr %5, i32 0, i32 1
-  %8 = getelementptr inbounds %"github.com/goplus/llgo/internal/runtime.itab", ptr %5, i32 0, i32 2
-  %9 = getelementptr inbounds %"github.com/goplus/llgo/internal/runtime.itab", ptr %5, i32 0, i32 4
-  %10 = getelementptr inbounds i64, ptr %9, i64 0
-  store ptr %0, ptr %6, align 8
-  store ptr %1, ptr %7, align 8
-  store i32 0, ptr %8, align 4
-  store i64 0, ptr %10, align 4
-  %11 = getelementptr inbounds %"github.com/goplus/llgo/internal/runtime.iface", ptr %3, i32 0, i32 1
-  store ptr %5, ptr %4, align 8
+  %3 = call ptr @"github.com/goplus/llgo/internal/runtime.Alloc"(i64 16)
+  %4 = getelementptr inbounds %"github.com/goplus/llgo/internal/runtime.itab", ptr %3, i32 0, i32 0
+  %5 = getelementptr inbounds %"github.com/goplus/llgo/internal/runtime.itab", ptr %3, i32 0, i32 1
+  %6 = getelementptr inbounds %"github.com/goplus/llgo/internal/runtime.itab", ptr %3, i32 0, i32 2
+  %7 = getelementptr inbounds %"github.com/goplus/llgo/internal/runtime.itab", ptr %3, i32 0, i32 4
+  %8 = getelementptr inbounds i64, ptr %7, i64 0
+  store ptr %0, ptr %4, align 8
+  store ptr %1, ptr %5, align 8
+  store i32 0, ptr %6, align 4
+  store i64 0, ptr %8, align 4
+  %9 = alloca %"github.com/goplus/llgo/internal/runtime.iface", align 8
+  %10 = getelementptr inbounds %"github.com/goplus/llgo/internal/runtime.iface", ptr %9, i32 0, i32 0
+  %11 = getelementptr inbounds %"github.com/goplus/llgo/internal/runtime.iface", ptr %9, i32 0, i32 1
+  store ptr %3, ptr %10, align 8
   store ptr %2, ptr %11, align 8
-  %12 = load %"github.com/goplus/llgo/internal/runtime.iface", ptr %3, align 8
+  %12 = load %"github.com/goplus/llgo/internal/runtime.iface", ptr %9, align 8
   ret %"github.com/goplus/llgo/internal/runtime.iface" %12
 }
 
@@ -281,6 +286,41 @@ _llgo_0:
   ret i64 %3
 }
 
+define void @"github.com/goplus/llgo/internal/runtime.TracePanic"(%"github.com/goplus/llgo/internal/runtime.iface" %0) {
+_llgo_0:
+  %1 = alloca %"github.com/goplus/llgo/internal/runtime.iface", align 8
+  store %"github.com/goplus/llgo/internal/runtime.iface" %0, ptr %1, align 8
+  %2 = getelementptr inbounds %"github.com/goplus/llgo/internal/runtime.iface", ptr %1, i32 0, i32 0
+  %3 = load ptr, ptr %2, align 8
+  %4 = getelementptr inbounds %"github.com/goplus/llgo/internal/runtime.itab", ptr %3, i32 0, i32 1
+  %5 = load ptr, ptr %4, align 8
+  %6 = call i32 (ptr, ...) @printf(ptr @2, ptr %5)
+  %7 = getelementptr inbounds %"github.com/goplus/llgo/internal/runtime.iface", ptr %1, i32 0, i32 0
+  %8 = load ptr, ptr %7, align 8
+  %9 = getelementptr inbounds %"github.com/goplus/llgo/internal/runtime.itab", ptr %8, i32 0, i32 1
+  %10 = load ptr, ptr %9, align 8
+  %11 = getelementptr inbounds %"github.com/goplus/llgo/internal/abi.Type", ptr %10, i32 0, i32 6
+  %12 = load i8, ptr %11, align 1
+  %13 = sext i8 %12 to i64
+  %14 = icmp eq i64 %13, 24
+  br i1 %14, label %_llgo_2, label %_llgo_1
+
+_llgo_1:                                          ; preds = %_llgo_2, %_llgo_0
+  ret void
+
+_llgo_2:                                          ; preds = %_llgo_0
+  %15 = getelementptr inbounds %"github.com/goplus/llgo/internal/runtime.iface", ptr %1, i32 0, i32 1
+  %16 = load ptr, ptr %15, align 8
+  %17 = getelementptr inbounds %"github.com/goplus/llgo/internal/runtime.String", ptr %16, i32 0, i32 1
+  %18 = load i64, ptr %17, align 4
+  %19 = add i64 %18, 1
+  %20 = alloca i8, i64 %19, align 1
+  %21 = load %"github.com/goplus/llgo/internal/runtime.String", ptr %16, align 8
+  %22 = call ptr @"github.com/goplus/llgo/internal/runtime.CStrCopy"(ptr %20, %"github.com/goplus/llgo/internal/runtime.String" %21)
+  %23 = call i32 (ptr, ...) @printf(ptr @3, ptr %22)
+  br label %_llgo_1
+}
+
 define ptr @"github.com/goplus/llgo/internal/runtime.basicType"(i64 %0) {
 _llgo_0:
   %1 = call ptr @"github.com/goplus/llgo/internal/runtime.Alloc"(i64 16)
@@ -386,6 +426,8 @@ declare ptr @malloc(i64)
 
 declare ptr @memcpy(ptr, ptr, i64)
 
+declare i32 @printf(ptr, ...)
+
 declare i32 @rand()
 
 declare void @"github.com/goplus/llgo/internal/abi.init"()
diff --git a/internal/runtime/z_c.go b/internal/runtime/z_c.go
index 6cca5b99..46de4e6a 100644
--- a/internal/runtime/z_c.go
+++ b/internal/runtime/z_c.go
@@ -19,6 +19,7 @@ package runtime
 import (
 	"unsafe"
 
+	"github.com/goplus/llgo/internal/abi"
 	"github.com/goplus/llgo/internal/runtime/c"
 )
 
@@ -27,18 +28,15 @@ func Alloc(size uintptr) unsafe.Pointer {
 	return c.Malloc(size)
 }
 
-/*
-// Panic panics with a value.
-func Panic(v Interface) {
-	c.Printf(c.String("Panic!!!\n"))
+// TracePanic prints panic message.
+func TracePanic(v Interface) {
+	c.Printf(c.Str("Panic(%p)\n"), v.tab._type)
 	kind := abi.Kind(v.tab._type.Kind_)
 	switch {
 	case kind == abi.String:
 		s := (*String)(v.data)
 		cs := c.Alloca(uintptr(s.len) + 1)
-		c.Memcpy(cs, s.data, uintptr(s.len))
-		(*[1 << 30]int8)(cs)[s.len] = 0
-		c.Printf(c.String("%s\n"), cs)
+		c.Printf(c.Str("panic: %s\n"), CStrCopy(cs, *s))
 	}
+	// TODO(xsw): other message type
 }
-*/
diff --git a/internal/runtime/z_iface.go b/internal/runtime/z_iface.go
index 2d35d8f9..c926c3f4 100644
--- a/internal/runtime/z_iface.go
+++ b/internal/runtime/z_iface.go
@@ -20,6 +20,7 @@ import (
 	"unsafe"
 
 	"github.com/goplus/llgo/internal/abi"
+	"github.com/goplus/llgo/internal/runtime/c"
 )
 
 // -----------------------------------------------------------------------------
@@ -35,29 +36,35 @@ var (
 type Interface = iface
 
 func MakeAnyInt(typ *Type, data uintptr) Interface {
+	tab := &itab{inter: TyAny, _type: typ, hash: 0, fun: [1]uintptr{0}}
 	return Interface{
-		tab:  &itab{inter: TyAny, _type: typ, hash: 0, fun: [1]uintptr{0}},
+		tab:  tab,
 		data: unsafe.Pointer(data),
 	}
 }
 
 func MakeAnyString(data string) Interface {
+	typ := Basic(abi.String)
+	tab := &itab{inter: TyAny, _type: typ, hash: 0, fun: [1]uintptr{0}}
+	c.Printf(c.Str("MakeAnyString(%p)\n"), typ)
 	return Interface{
-		tab:  &itab{inter: TyAny, _type: Basic(abi.String), hash: 0, fun: [1]uintptr{0}},
+		tab:  tab,
 		data: unsafe.Pointer(&data),
 	}
 }
 
 func MakeAny(typ *Type, data unsafe.Pointer) Interface {
+	tab := &itab{inter: TyAny, _type: typ, hash: 0, fun: [1]uintptr{0}}
 	return Interface{
-		tab:  &itab{inter: TyAny, _type: typ, hash: 0, fun: [1]uintptr{0}},
+		tab:  tab,
 		data: data,
 	}
 }
 
 func MakeInterface(inter *InterfaceType, typ *Type, data unsafe.Pointer) Interface {
+	tab := &itab{inter: inter, _type: typ, hash: 0, fun: [1]uintptr{0}}
 	return Interface{
-		tab:  &itab{inter: inter, _type: typ, hash: 0, fun: [1]uintptr{0}},
+		tab:  tab,
 		data: data,
 	}
 }
diff --git a/ssa/stmt_builder.go b/ssa/stmt_builder.go
index 47e50c9d..5d0e75b7 100644
--- a/ssa/stmt_builder.go
+++ b/ssa/stmt_builder.go
@@ -73,7 +73,9 @@ func (b Builder) Panic(v Expr) {
 	if debugInstr {
 		log.Printf("Panic %v\n", v.impl)
 	}
-	b.impl.CreateUnreachable() // TODO(xsw): pass v
+	pkg := b.fn.pkg
+	b.Call(pkg.rtFunc("TracePanic"), v)
+	b.impl.CreateUnreachable()
 }
 
 // Unreachable emits an unreachable instruction.