diff --git a/cl/_testgo/cgobase/in.go b/cl/_testgo/cgobase/in.go
new file mode 100644
index 00000000..576668a2
--- /dev/null
+++ b/cl/_testgo/cgobase/in.go
@@ -0,0 +1,55 @@
+package main
+
+/*
+#include <stdio.h>
+#include <stdlib.h>
+#include <math.h>
+*/
+import "C"
+import (
+	"fmt"
+	"unsafe"
+)
+
+func main() {
+	// C.CString example
+	cstr := C.CString("Hello, World!")
+	C.puts(cstr)
+
+	// C.CBytes example
+	bytes := []byte{65, 66, 67, 68} // ABCD
+	cbytes := C.CBytes(bytes)
+
+	// C.GoString example
+	gostr := C.GoString(cstr)
+	println("Converted back to Go string: ", gostr)
+
+	// C.GoStringN example (with length limit)
+	gostringN := C.GoStringN(cstr, 5) // only take first 5 characters
+	println("Length-limited string: ", gostringN)
+
+	// C.GoBytes example
+	gobytes := C.GoBytes(cbytes, 4) // 4 is the length
+	println("Converted back to Go byte slice: ", gobytes)
+
+	// C math library examples
+	x := 2.0
+	// Calculate square root
+	sqrtResult := C.sqrt(C.double(x))
+	fmt.Printf("sqrt(%v) = %v\n", x, float64(sqrtResult))
+
+	// Calculate sine
+	sinResult := C.sin(C.double(x))
+	fmt.Printf("sin(%v) = %v\n", x, float64(sinResult))
+
+	// Calculate cosine
+	cosResult := C.cos(C.double(x))
+	fmt.Printf("cos(%v) = %v\n", x, float64(cosResult))
+
+	// Calculate natural logarithm
+	logResult := C.log(C.double(x))
+	fmt.Printf("log(%v) = %v\n", x, float64(logResult))
+
+	C.free(unsafe.Pointer(cstr))
+	C.free(cbytes)
+}
diff --git a/cl/_testgo/cgobase/out.ll b/cl/_testgo/cgobase/out.ll
new file mode 100644
index 00000000..2acb5b16
--- /dev/null
+++ b/cl/_testgo/cgobase/out.ll
@@ -0,0 +1,479 @@
+; ModuleID = 'main'
+source_filename = "main"
+
+%"github.com/goplus/llgo/internal/runtime.String" = type { ptr, i64 }
+%"github.com/goplus/llgo/internal/runtime.Slice" = type { ptr, i64, i64 }
+%"github.com/goplus/llgo/internal/runtime.eface" = type { ptr, ptr }
+%"github.com/goplus/llgo/internal/runtime.iface" = type { ptr, ptr }
+
+@"main.init$guard" = global i1 false, align 1
+@_cgo_fc2717469476_Cfunc_cos = external global i8, align 1
+@_cgo_fc2717469476_Cfunc_free = external global i8, align 1
+@_cgo_fc2717469476_Cfunc_log = external global i8, align 1
+@_cgo_fc2717469476_Cfunc_puts = external global i8, align 1
+@_cgo_fc2717469476_Cfunc_sin = external global i8, align 1
+@_cgo_fc2717469476_Cfunc_sqrt = external global i8, align 1
+@_cgo_fc2717469476_Cfunc__Cmalloc = external global i8, align 1
+@__llgo_argc = global i32 0, align 4
+@__llgo_argv = global ptr null, align 8
+@0 = private unnamed_addr constant [13 x i8] c"Hello, World!", align 1
+@1 = private unnamed_addr constant [29 x i8] c"Converted back to Go string: ", align 1
+@2 = private unnamed_addr constant [23 x i8] c"Length-limited string: ", align 1
+@3 = private unnamed_addr constant [33 x i8] c"Converted back to Go byte slice: ", align 1
+@_llgo_float64 = linkonce global ptr null, align 8
+@4 = private unnamed_addr constant [14 x i8] c"sqrt(%v) = %v\0A", align 1
+@5 = private unnamed_addr constant [13 x i8] c"sin(%v) = %v\0A", align 1
+@6 = private unnamed_addr constant [13 x i8] c"cos(%v) = %v\0A", align 1
+@7 = private unnamed_addr constant [13 x i8] c"log(%v) = %v\0A", align 1
+@_llgo_byte = linkonce global ptr null, align 8
+@"[]_llgo_byte" = linkonce global ptr null, align 8
+@_llgo_Pointer = linkonce global ptr null, align 8
+
+define void @main.init() {
+_llgo_0:
+  %0 = load i1, ptr @"main.init$guard", align 1
+  br i1 %0, label %_llgo_2, label %_llgo_1
+
+_llgo_1:                                          ; preds = %_llgo_0
+  store i1 true, ptr @"main.init$guard", align 1
+  call void @syscall.init()
+  call void @fmt.init()
+  call void @"main.init$after"()
+  br label %_llgo_2
+
+_llgo_2:                                          ; preds = %_llgo_1, %_llgo_0
+  ret void
+}
+
+define i32 @main(i32 %0, ptr %1) {
+_llgo_0:
+  store i32 %0, ptr @__llgo_argc, align 4
+  store ptr %1, ptr @__llgo_argv, align 8
+  call void @"github.com/goplus/llgo/internal/runtime.init"()
+  call void @main.init()
+  %2 = call ptr @"github.com/goplus/llgo/internal/runtime.AllocZ"(i64 8)
+  %3 = alloca %"github.com/goplus/llgo/internal/runtime.String", align 8
+  %4 = getelementptr inbounds %"github.com/goplus/llgo/internal/runtime.String", ptr %3, i32 0, i32 0
+  store ptr @0, ptr %4, align 8
+  %5 = getelementptr inbounds %"github.com/goplus/llgo/internal/runtime.String", ptr %3, i32 0, i32 1
+  store i64 13, ptr %5, align 4
+  %6 = load %"github.com/goplus/llgo/internal/runtime.String", ptr %3, align 8
+  %7 = call ptr @"github.com/goplus/llgo/internal/runtime.CString"(%"github.com/goplus/llgo/internal/runtime.String" %6)
+  store ptr %7, ptr %2, align 8
+  %8 = load ptr, ptr %2, align 8
+  %9 = call i32 @puts(ptr %8)
+  %10 = call ptr @"github.com/goplus/llgo/internal/runtime.AllocZ"(i64 24)
+  %11 = call ptr @"github.com/goplus/llgo/internal/runtime.AllocZ"(i64 4)
+  %12 = getelementptr inbounds i8, ptr %11, i64 0
+  store i8 65, ptr %12, align 1
+  %13 = getelementptr inbounds i8, ptr %11, i64 1
+  store i8 66, ptr %13, align 1
+  %14 = getelementptr inbounds i8, ptr %11, i64 2
+  store i8 67, ptr %14, align 1
+  %15 = getelementptr inbounds i8, ptr %11, i64 3
+  store i8 68, ptr %15, align 1
+  %16 = alloca %"github.com/goplus/llgo/internal/runtime.Slice", align 8
+  %17 = getelementptr inbounds %"github.com/goplus/llgo/internal/runtime.Slice", ptr %16, i32 0, i32 0
+  store ptr %11, ptr %17, align 8
+  %18 = getelementptr inbounds %"github.com/goplus/llgo/internal/runtime.Slice", ptr %16, i32 0, i32 1
+  store i64 4, ptr %18, align 4
+  %19 = getelementptr inbounds %"github.com/goplus/llgo/internal/runtime.Slice", ptr %16, i32 0, i32 2
+  store i64 4, ptr %19, align 4
+  %20 = load %"github.com/goplus/llgo/internal/runtime.Slice", ptr %16, align 8
+  store %"github.com/goplus/llgo/internal/runtime.Slice" %20, ptr %10, align 8
+  %21 = call ptr @"github.com/goplus/llgo/internal/runtime.AllocZ"(i64 8)
+  %22 = call ptr @"github.com/goplus/llgo/internal/runtime.AllocU"(i64 8)
+  %23 = getelementptr inbounds { ptr }, ptr %22, i32 0, i32 0
+  store ptr %10, ptr %23, align 8
+  %24 = alloca { ptr, ptr }, align 8
+  %25 = getelementptr inbounds { ptr, ptr }, ptr %24, i32 0, i32 0
+  store ptr @"main.main$1", ptr %25, align 8
+  %26 = getelementptr inbounds { ptr, ptr }, ptr %24, i32 0, i32 1
+  store ptr %22, ptr %26, align 8
+  %27 = load { ptr, ptr }, ptr %24, align 8
+  %28 = extractvalue { ptr, ptr } %27, 1
+  %29 = extractvalue { ptr, ptr } %27, 0
+  %30 = call ptr %29(ptr %28)
+  store ptr %30, ptr %21, align 8
+  %31 = load ptr, ptr %2, align 8
+  %32 = call %"github.com/goplus/llgo/internal/runtime.String" @"github.com/goplus/llgo/internal/runtime.GoString"(ptr %31)
+  %33 = alloca %"github.com/goplus/llgo/internal/runtime.String", align 8
+  %34 = getelementptr inbounds %"github.com/goplus/llgo/internal/runtime.String", ptr %33, i32 0, i32 0
+  store ptr @1, ptr %34, align 8
+  %35 = getelementptr inbounds %"github.com/goplus/llgo/internal/runtime.String", ptr %33, i32 0, i32 1
+  store i64 29, ptr %35, align 4
+  %36 = load %"github.com/goplus/llgo/internal/runtime.String", ptr %33, align 8
+  call void @"github.com/goplus/llgo/internal/runtime.PrintString"(%"github.com/goplus/llgo/internal/runtime.String" %36)
+  call void @"github.com/goplus/llgo/internal/runtime.PrintByte"(i8 32)
+  call void @"github.com/goplus/llgo/internal/runtime.PrintString"(%"github.com/goplus/llgo/internal/runtime.String" %32)
+  call void @"github.com/goplus/llgo/internal/runtime.PrintByte"(i8 10)
+  %37 = load ptr, ptr %2, align 8
+  %38 = call %"github.com/goplus/llgo/internal/runtime.String" @"github.com/goplus/llgo/internal/runtime.GoStringN"(ptr %37, i32 5)
+  %39 = alloca %"github.com/goplus/llgo/internal/runtime.String", align 8
+  %40 = getelementptr inbounds %"github.com/goplus/llgo/internal/runtime.String", ptr %39, i32 0, i32 0
+  store ptr @2, ptr %40, align 8
+  %41 = getelementptr inbounds %"github.com/goplus/llgo/internal/runtime.String", ptr %39, i32 0, i32 1
+  store i64 23, ptr %41, align 4
+  %42 = load %"github.com/goplus/llgo/internal/runtime.String", ptr %39, align 8
+  call void @"github.com/goplus/llgo/internal/runtime.PrintString"(%"github.com/goplus/llgo/internal/runtime.String" %42)
+  call void @"github.com/goplus/llgo/internal/runtime.PrintByte"(i8 32)
+  call void @"github.com/goplus/llgo/internal/runtime.PrintString"(%"github.com/goplus/llgo/internal/runtime.String" %38)
+  call void @"github.com/goplus/llgo/internal/runtime.PrintByte"(i8 10)
+  %43 = call ptr @"github.com/goplus/llgo/internal/runtime.AllocU"(i64 8)
+  %44 = getelementptr inbounds { ptr }, ptr %43, i32 0, i32 0
+  store ptr %21, ptr %44, align 8
+  %45 = alloca { ptr, ptr }, align 8
+  %46 = getelementptr inbounds { ptr, ptr }, ptr %45, i32 0, i32 0
+  store ptr @"main.main$2", ptr %46, align 8
+  %47 = getelementptr inbounds { ptr, ptr }, ptr %45, i32 0, i32 1
+  store ptr %43, ptr %47, align 8
+  %48 = load { ptr, ptr }, ptr %45, align 8
+  %49 = extractvalue { ptr, ptr } %48, 1
+  %50 = extractvalue { ptr, ptr } %48, 0
+  %51 = call %"github.com/goplus/llgo/internal/runtime.Slice" %50(ptr %49)
+  %52 = alloca %"github.com/goplus/llgo/internal/runtime.String", align 8
+  %53 = getelementptr inbounds %"github.com/goplus/llgo/internal/runtime.String", ptr %52, i32 0, i32 0
+  store ptr @3, ptr %53, align 8
+  %54 = getelementptr inbounds %"github.com/goplus/llgo/internal/runtime.String", ptr %52, i32 0, i32 1
+  store i64 33, ptr %54, align 4
+  %55 = load %"github.com/goplus/llgo/internal/runtime.String", ptr %52, align 8
+  call void @"github.com/goplus/llgo/internal/runtime.PrintString"(%"github.com/goplus/llgo/internal/runtime.String" %55)
+  call void @"github.com/goplus/llgo/internal/runtime.PrintByte"(i8 32)
+  call void @"github.com/goplus/llgo/internal/runtime.PrintSlice"(%"github.com/goplus/llgo/internal/runtime.Slice" %51)
+  call void @"github.com/goplus/llgo/internal/runtime.PrintByte"(i8 10)
+  %56 = call double @sqrt(double 2.000000e+00)
+  %57 = call ptr @"github.com/goplus/llgo/internal/runtime.AllocZ"(i64 32)
+  %58 = getelementptr inbounds %"github.com/goplus/llgo/internal/runtime.eface", ptr %57, i64 0
+  %59 = load ptr, ptr @_llgo_float64, align 8
+  %60 = alloca %"github.com/goplus/llgo/internal/runtime.eface", align 8
+  %61 = getelementptr inbounds %"github.com/goplus/llgo/internal/runtime.eface", ptr %60, i32 0, i32 0
+  store ptr %59, ptr %61, align 8
+  %62 = getelementptr inbounds %"github.com/goplus/llgo/internal/runtime.eface", ptr %60, i32 0, i32 1
+  store ptr inttoptr (i64 4611686018427387904 to ptr), ptr %62, align 8
+  %63 = load %"github.com/goplus/llgo/internal/runtime.eface", ptr %60, align 8
+  store %"github.com/goplus/llgo/internal/runtime.eface" %63, ptr %58, align 8
+  %64 = getelementptr inbounds %"github.com/goplus/llgo/internal/runtime.eface", ptr %57, i64 1
+  %65 = load ptr, ptr @_llgo_float64, align 8
+  %66 = bitcast double %56 to i64
+  %67 = inttoptr i64 %66 to ptr
+  %68 = alloca %"github.com/goplus/llgo/internal/runtime.eface", align 8
+  %69 = getelementptr inbounds %"github.com/goplus/llgo/internal/runtime.eface", ptr %68, i32 0, i32 0
+  store ptr %65, ptr %69, align 8
+  %70 = getelementptr inbounds %"github.com/goplus/llgo/internal/runtime.eface", ptr %68, i32 0, i32 1
+  store ptr %67, ptr %70, align 8
+  %71 = load %"github.com/goplus/llgo/internal/runtime.eface", ptr %68, align 8
+  store %"github.com/goplus/llgo/internal/runtime.eface" %71, ptr %64, align 8
+  %72 = alloca %"github.com/goplus/llgo/internal/runtime.Slice", align 8
+  %73 = getelementptr inbounds %"github.com/goplus/llgo/internal/runtime.Slice", ptr %72, i32 0, i32 0
+  store ptr %57, ptr %73, align 8
+  %74 = getelementptr inbounds %"github.com/goplus/llgo/internal/runtime.Slice", ptr %72, i32 0, i32 1
+  store i64 2, ptr %74, align 4
+  %75 = getelementptr inbounds %"github.com/goplus/llgo/internal/runtime.Slice", ptr %72, i32 0, i32 2
+  store i64 2, ptr %75, align 4
+  %76 = load %"github.com/goplus/llgo/internal/runtime.Slice", ptr %72, align 8
+  %77 = alloca %"github.com/goplus/llgo/internal/runtime.String", align 8
+  %78 = getelementptr inbounds %"github.com/goplus/llgo/internal/runtime.String", ptr %77, i32 0, i32 0
+  store ptr @4, ptr %78, align 8
+  %79 = getelementptr inbounds %"github.com/goplus/llgo/internal/runtime.String", ptr %77, i32 0, i32 1
+  store i64 14, ptr %79, align 4
+  %80 = load %"github.com/goplus/llgo/internal/runtime.String", ptr %77, align 8
+  %81 = call { i64, %"github.com/goplus/llgo/internal/runtime.iface" } @fmt.Printf(%"github.com/goplus/llgo/internal/runtime.String" %80, %"github.com/goplus/llgo/internal/runtime.Slice" %76)
+  %82 = call double @sin(double 2.000000e+00)
+  %83 = call ptr @"github.com/goplus/llgo/internal/runtime.AllocZ"(i64 32)
+  %84 = getelementptr inbounds %"github.com/goplus/llgo/internal/runtime.eface", ptr %83, i64 0
+  %85 = load ptr, ptr @_llgo_float64, align 8
+  %86 = alloca %"github.com/goplus/llgo/internal/runtime.eface", align 8
+  %87 = getelementptr inbounds %"github.com/goplus/llgo/internal/runtime.eface", ptr %86, i32 0, i32 0
+  store ptr %85, ptr %87, align 8
+  %88 = getelementptr inbounds %"github.com/goplus/llgo/internal/runtime.eface", ptr %86, i32 0, i32 1
+  store ptr inttoptr (i64 4611686018427387904 to ptr), ptr %88, align 8
+  %89 = load %"github.com/goplus/llgo/internal/runtime.eface", ptr %86, align 8
+  store %"github.com/goplus/llgo/internal/runtime.eface" %89, ptr %84, align 8
+  %90 = getelementptr inbounds %"github.com/goplus/llgo/internal/runtime.eface", ptr %83, i64 1
+  %91 = load ptr, ptr @_llgo_float64, align 8
+  %92 = bitcast double %82 to i64
+  %93 = inttoptr i64 %92 to ptr
+  %94 = alloca %"github.com/goplus/llgo/internal/runtime.eface", align 8
+  %95 = getelementptr inbounds %"github.com/goplus/llgo/internal/runtime.eface", ptr %94, i32 0, i32 0
+  store ptr %91, ptr %95, align 8
+  %96 = getelementptr inbounds %"github.com/goplus/llgo/internal/runtime.eface", ptr %94, i32 0, i32 1
+  store ptr %93, ptr %96, align 8
+  %97 = load %"github.com/goplus/llgo/internal/runtime.eface", ptr %94, align 8
+  store %"github.com/goplus/llgo/internal/runtime.eface" %97, ptr %90, align 8
+  %98 = alloca %"github.com/goplus/llgo/internal/runtime.Slice", align 8
+  %99 = getelementptr inbounds %"github.com/goplus/llgo/internal/runtime.Slice", ptr %98, i32 0, i32 0
+  store ptr %83, ptr %99, align 8
+  %100 = getelementptr inbounds %"github.com/goplus/llgo/internal/runtime.Slice", ptr %98, i32 0, i32 1
+  store i64 2, ptr %100, align 4
+  %101 = getelementptr inbounds %"github.com/goplus/llgo/internal/runtime.Slice", ptr %98, i32 0, i32 2
+  store i64 2, ptr %101, align 4
+  %102 = load %"github.com/goplus/llgo/internal/runtime.Slice", ptr %98, align 8
+  %103 = alloca %"github.com/goplus/llgo/internal/runtime.String", align 8
+  %104 = getelementptr inbounds %"github.com/goplus/llgo/internal/runtime.String", ptr %103, i32 0, i32 0
+  store ptr @5, ptr %104, align 8
+  %105 = getelementptr inbounds %"github.com/goplus/llgo/internal/runtime.String", ptr %103, i32 0, i32 1
+  store i64 13, ptr %105, align 4
+  %106 = load %"github.com/goplus/llgo/internal/runtime.String", ptr %103, align 8
+  %107 = call { i64, %"github.com/goplus/llgo/internal/runtime.iface" } @fmt.Printf(%"github.com/goplus/llgo/internal/runtime.String" %106, %"github.com/goplus/llgo/internal/runtime.Slice" %102)
+  %108 = call double @cos(double 2.000000e+00)
+  %109 = call ptr @"github.com/goplus/llgo/internal/runtime.AllocZ"(i64 32)
+  %110 = getelementptr inbounds %"github.com/goplus/llgo/internal/runtime.eface", ptr %109, i64 0
+  %111 = load ptr, ptr @_llgo_float64, align 8
+  %112 = alloca %"github.com/goplus/llgo/internal/runtime.eface", align 8
+  %113 = getelementptr inbounds %"github.com/goplus/llgo/internal/runtime.eface", ptr %112, i32 0, i32 0
+  store ptr %111, ptr %113, align 8
+  %114 = getelementptr inbounds %"github.com/goplus/llgo/internal/runtime.eface", ptr %112, i32 0, i32 1
+  store ptr inttoptr (i64 4611686018427387904 to ptr), ptr %114, align 8
+  %115 = load %"github.com/goplus/llgo/internal/runtime.eface", ptr %112, align 8
+  store %"github.com/goplus/llgo/internal/runtime.eface" %115, ptr %110, align 8
+  %116 = getelementptr inbounds %"github.com/goplus/llgo/internal/runtime.eface", ptr %109, i64 1
+  %117 = load ptr, ptr @_llgo_float64, align 8
+  %118 = bitcast double %108 to i64
+  %119 = inttoptr i64 %118 to ptr
+  %120 = alloca %"github.com/goplus/llgo/internal/runtime.eface", align 8
+  %121 = getelementptr inbounds %"github.com/goplus/llgo/internal/runtime.eface", ptr %120, i32 0, i32 0
+  store ptr %117, ptr %121, align 8
+  %122 = getelementptr inbounds %"github.com/goplus/llgo/internal/runtime.eface", ptr %120, i32 0, i32 1
+  store ptr %119, ptr %122, align 8
+  %123 = load %"github.com/goplus/llgo/internal/runtime.eface", ptr %120, align 8
+  store %"github.com/goplus/llgo/internal/runtime.eface" %123, ptr %116, align 8
+  %124 = alloca %"github.com/goplus/llgo/internal/runtime.Slice", align 8
+  %125 = getelementptr inbounds %"github.com/goplus/llgo/internal/runtime.Slice", ptr %124, i32 0, i32 0
+  store ptr %109, ptr %125, align 8
+  %126 = getelementptr inbounds %"github.com/goplus/llgo/internal/runtime.Slice", ptr %124, i32 0, i32 1
+  store i64 2, ptr %126, align 4
+  %127 = getelementptr inbounds %"github.com/goplus/llgo/internal/runtime.Slice", ptr %124, i32 0, i32 2
+  store i64 2, ptr %127, align 4
+  %128 = load %"github.com/goplus/llgo/internal/runtime.Slice", ptr %124, align 8
+  %129 = alloca %"github.com/goplus/llgo/internal/runtime.String", align 8
+  %130 = getelementptr inbounds %"github.com/goplus/llgo/internal/runtime.String", ptr %129, i32 0, i32 0
+  store ptr @6, ptr %130, align 8
+  %131 = getelementptr inbounds %"github.com/goplus/llgo/internal/runtime.String", ptr %129, i32 0, i32 1
+  store i64 13, ptr %131, align 4
+  %132 = load %"github.com/goplus/llgo/internal/runtime.String", ptr %129, align 8
+  %133 = call { i64, %"github.com/goplus/llgo/internal/runtime.iface" } @fmt.Printf(%"github.com/goplus/llgo/internal/runtime.String" %132, %"github.com/goplus/llgo/internal/runtime.Slice" %128)
+  %134 = call double @log(double 2.000000e+00)
+  %135 = call ptr @"github.com/goplus/llgo/internal/runtime.AllocZ"(i64 32)
+  %136 = getelementptr inbounds %"github.com/goplus/llgo/internal/runtime.eface", ptr %135, i64 0
+  %137 = load ptr, ptr @_llgo_float64, align 8
+  %138 = alloca %"github.com/goplus/llgo/internal/runtime.eface", align 8
+  %139 = getelementptr inbounds %"github.com/goplus/llgo/internal/runtime.eface", ptr %138, i32 0, i32 0
+  store ptr %137, ptr %139, align 8
+  %140 = getelementptr inbounds %"github.com/goplus/llgo/internal/runtime.eface", ptr %138, i32 0, i32 1
+  store ptr inttoptr (i64 4611686018427387904 to ptr), ptr %140, align 8
+  %141 = load %"github.com/goplus/llgo/internal/runtime.eface", ptr %138, align 8
+  store %"github.com/goplus/llgo/internal/runtime.eface" %141, ptr %136, align 8
+  %142 = getelementptr inbounds %"github.com/goplus/llgo/internal/runtime.eface", ptr %135, i64 1
+  %143 = load ptr, ptr @_llgo_float64, align 8
+  %144 = bitcast double %134 to i64
+  %145 = inttoptr i64 %144 to ptr
+  %146 = alloca %"github.com/goplus/llgo/internal/runtime.eface", align 8
+  %147 = getelementptr inbounds %"github.com/goplus/llgo/internal/runtime.eface", ptr %146, i32 0, i32 0
+  store ptr %143, ptr %147, align 8
+  %148 = getelementptr inbounds %"github.com/goplus/llgo/internal/runtime.eface", ptr %146, i32 0, i32 1
+  store ptr %145, ptr %148, align 8
+  %149 = load %"github.com/goplus/llgo/internal/runtime.eface", ptr %146, align 8
+  store %"github.com/goplus/llgo/internal/runtime.eface" %149, ptr %142, align 8
+  %150 = alloca %"github.com/goplus/llgo/internal/runtime.Slice", align 8
+  %151 = getelementptr inbounds %"github.com/goplus/llgo/internal/runtime.Slice", ptr %150, i32 0, i32 0
+  store ptr %135, ptr %151, align 8
+  %152 = getelementptr inbounds %"github.com/goplus/llgo/internal/runtime.Slice", ptr %150, i32 0, i32 1
+  store i64 2, ptr %152, align 4
+  %153 = getelementptr inbounds %"github.com/goplus/llgo/internal/runtime.Slice", ptr %150, i32 0, i32 2
+  store i64 2, ptr %153, align 4
+  %154 = load %"github.com/goplus/llgo/internal/runtime.Slice", ptr %150, align 8
+  %155 = alloca %"github.com/goplus/llgo/internal/runtime.String", align 8
+  %156 = getelementptr inbounds %"github.com/goplus/llgo/internal/runtime.String", ptr %155, i32 0, i32 0
+  store ptr @7, ptr %156, align 8
+  %157 = getelementptr inbounds %"github.com/goplus/llgo/internal/runtime.String", ptr %155, i32 0, i32 1
+  store i64 13, ptr %157, align 4
+  %158 = load %"github.com/goplus/llgo/internal/runtime.String", ptr %155, align 8
+  %159 = call { i64, %"github.com/goplus/llgo/internal/runtime.iface" } @fmt.Printf(%"github.com/goplus/llgo/internal/runtime.String" %158, %"github.com/goplus/llgo/internal/runtime.Slice" %154)
+  %160 = call ptr @"github.com/goplus/llgo/internal/runtime.AllocU"(i64 8)
+  %161 = getelementptr inbounds { ptr }, ptr %160, i32 0, i32 0
+  store ptr %2, ptr %161, align 8
+  %162 = alloca { ptr, ptr }, align 8
+  %163 = getelementptr inbounds { ptr, ptr }, ptr %162, i32 0, i32 0
+  store ptr @"main.main$3", ptr %163, align 8
+  %164 = getelementptr inbounds { ptr, ptr }, ptr %162, i32 0, i32 1
+  store ptr %160, ptr %164, align 8
+  %165 = load { ptr, ptr }, ptr %162, align 8
+  %166 = extractvalue { ptr, ptr } %165, 1
+  %167 = extractvalue { ptr, ptr } %165, 0
+  call void %167(ptr %166)
+  %168 = call ptr @"github.com/goplus/llgo/internal/runtime.AllocU"(i64 8)
+  %169 = getelementptr inbounds { ptr }, ptr %168, i32 0, i32 0
+  store ptr %21, ptr %169, align 8
+  %170 = alloca { ptr, ptr }, align 8
+  %171 = getelementptr inbounds { ptr, ptr }, ptr %170, i32 0, i32 0
+  store ptr @"main.main$4", ptr %171, align 8
+  %172 = getelementptr inbounds { ptr, ptr }, ptr %170, i32 0, i32 1
+  store ptr %168, ptr %172, align 8
+  %173 = load { ptr, ptr }, ptr %170, align 8
+  %174 = extractvalue { ptr, ptr } %173, 1
+  %175 = extractvalue { ptr, ptr } %173, 0
+  call void %175(ptr %174)
+  ret i32 0
+}
+
+define ptr @"main.main$1"(ptr %0) {
+_llgo_0:
+  %1 = load { ptr }, ptr %0, align 8
+  %2 = extractvalue { ptr } %1, 0
+  %3 = load %"github.com/goplus/llgo/internal/runtime.Slice", ptr %2, align 8
+  %4 = load ptr, ptr @_llgo_byte, align 8
+  %5 = load ptr, ptr @"[]_llgo_byte", align 8
+  %6 = call ptr @"github.com/goplus/llgo/internal/runtime.AllocU"(i64 24)
+  store %"github.com/goplus/llgo/internal/runtime.Slice" %3, ptr %6, align 8
+  %7 = alloca %"github.com/goplus/llgo/internal/runtime.eface", align 8
+  %8 = getelementptr inbounds %"github.com/goplus/llgo/internal/runtime.eface", ptr %7, i32 0, i32 0
+  store ptr %5, ptr %8, align 8
+  %9 = getelementptr inbounds %"github.com/goplus/llgo/internal/runtime.eface", ptr %7, i32 0, i32 1
+  store ptr %6, ptr %9, align 8
+  %10 = load %"github.com/goplus/llgo/internal/runtime.eface", ptr %7, align 8
+  %11 = call ptr @"github.com/goplus/llgo/internal/runtime.CBytes"(%"github.com/goplus/llgo/internal/runtime.Slice" %3)
+  ret ptr %11
+}
+
+define %"github.com/goplus/llgo/internal/runtime.Slice" @"main.main$2"(ptr %0) {
+_llgo_0:
+  %1 = load { ptr }, ptr %0, align 8
+  %2 = extractvalue { ptr } %1, 0
+  %3 = load ptr, ptr %2, align 8
+  %4 = load ptr, ptr @_llgo_Pointer, align 8
+  %5 = alloca %"github.com/goplus/llgo/internal/runtime.eface", align 8
+  %6 = getelementptr inbounds %"github.com/goplus/llgo/internal/runtime.eface", ptr %5, i32 0, i32 0
+  store ptr %4, ptr %6, align 8
+  %7 = getelementptr inbounds %"github.com/goplus/llgo/internal/runtime.eface", ptr %5, i32 0, i32 1
+  store ptr %3, ptr %7, align 8
+  %8 = load %"github.com/goplus/llgo/internal/runtime.eface", ptr %5, align 8
+  %9 = call %"github.com/goplus/llgo/internal/runtime.Slice" @"github.com/goplus/llgo/internal/runtime.GoBytes"(ptr %3, i32 4)
+  ret %"github.com/goplus/llgo/internal/runtime.Slice" %9
+}
+
+define void @"main.main$3"(ptr %0) {
+_llgo_0:
+  %1 = load { ptr }, ptr %0, align 8
+  %2 = extractvalue { ptr } %1, 0
+  %3 = load ptr, ptr %2, align 8
+  %4 = load ptr, ptr @_llgo_Pointer, align 8
+  %5 = alloca %"github.com/goplus/llgo/internal/runtime.eface", align 8
+  %6 = getelementptr inbounds %"github.com/goplus/llgo/internal/runtime.eface", ptr %5, i32 0, i32 0
+  store ptr %4, ptr %6, align 8
+  %7 = getelementptr inbounds %"github.com/goplus/llgo/internal/runtime.eface", ptr %5, i32 0, i32 1
+  store ptr %3, ptr %7, align 8
+  %8 = load %"github.com/goplus/llgo/internal/runtime.eface", ptr %5, align 8
+  %9 = call [0 x i8] @free(ptr %3)
+  ret void
+}
+
+define void @"main.main$4"(ptr %0) {
+_llgo_0:
+  %1 = load { ptr }, ptr %0, align 8
+  %2 = extractvalue { ptr } %1, 0
+  %3 = load ptr, ptr %2, align 8
+  %4 = load ptr, ptr @_llgo_Pointer, align 8
+  %5 = alloca %"github.com/goplus/llgo/internal/runtime.eface", align 8
+  %6 = getelementptr inbounds %"github.com/goplus/llgo/internal/runtime.eface", ptr %5, i32 0, i32 0
+  store ptr %4, ptr %6, align 8
+  %7 = getelementptr inbounds %"github.com/goplus/llgo/internal/runtime.eface", ptr %5, i32 0, i32 1
+  store ptr %3, ptr %7, align 8
+  %8 = load %"github.com/goplus/llgo/internal/runtime.eface", ptr %5, align 8
+  %9 = call [0 x i8] @free(ptr %3)
+  ret void
+}
+
+declare void @runtime.throw(%"github.com/goplus/llgo/internal/runtime.String")
+
+declare void @syscall.init()
+
+declare void @fmt.init()
+
+declare void @"github.com/goplus/llgo/internal/runtime.init"()
+
+declare ptr @"github.com/goplus/llgo/internal/runtime.AllocZ"(i64)
+
+declare ptr @"github.com/goplus/llgo/internal/runtime.CString"(%"github.com/goplus/llgo/internal/runtime.String")
+
+declare i32 @puts(ptr)
+
+declare ptr @"github.com/goplus/llgo/internal/runtime.AllocU"(i64)
+
+declare %"github.com/goplus/llgo/internal/runtime.String" @"github.com/goplus/llgo/internal/runtime.GoString"(ptr)
+
+declare void @"github.com/goplus/llgo/internal/runtime.PrintString"(%"github.com/goplus/llgo/internal/runtime.String")
+
+declare void @"github.com/goplus/llgo/internal/runtime.PrintByte"(i8)
+
+declare %"github.com/goplus/llgo/internal/runtime.String" @"github.com/goplus/llgo/internal/runtime.GoStringN"(ptr, i64)
+
+declare void @"github.com/goplus/llgo/internal/runtime.PrintSlice"(%"github.com/goplus/llgo/internal/runtime.Slice")
+
+declare double @sqrt(double)
+
+define void @"main.init$after"() {
+_llgo_0:
+  %0 = load ptr, ptr @_llgo_float64, align 8
+  %1 = icmp eq ptr %0, null
+  br i1 %1, label %_llgo_1, label %_llgo_2
+
+_llgo_1:                                          ; preds = %_llgo_0
+  %2 = call ptr @"github.com/goplus/llgo/internal/runtime.Basic"(i64 46)
+  store ptr %2, ptr @_llgo_float64, align 8
+  br label %_llgo_2
+
+_llgo_2:                                          ; preds = %_llgo_1, %_llgo_0
+  %3 = load ptr, ptr @_llgo_byte, align 8
+  %4 = icmp eq ptr %3, null
+  br i1 %4, label %_llgo_3, label %_llgo_4
+
+_llgo_3:                                          ; preds = %_llgo_2
+  %5 = call ptr @"github.com/goplus/llgo/internal/runtime.Basic"(i64 40)
+  store ptr %5, ptr @_llgo_byte, align 8
+  br label %_llgo_4
+
+_llgo_4:                                          ; preds = %_llgo_3, %_llgo_2
+  %6 = load ptr, ptr @"[]_llgo_byte", align 8
+  %7 = icmp eq ptr %6, null
+  br i1 %7, label %_llgo_5, label %_llgo_6
+
+_llgo_5:                                          ; preds = %_llgo_4
+  %8 = call ptr @"github.com/goplus/llgo/internal/runtime.Basic"(i64 40)
+  %9 = call ptr @"github.com/goplus/llgo/internal/runtime.SliceOf"(ptr %8)
+  store ptr %9, ptr @"[]_llgo_byte", align 8
+  br label %_llgo_6
+
+_llgo_6:                                          ; preds = %_llgo_5, %_llgo_4
+  %10 = load ptr, ptr @_llgo_Pointer, align 8
+  %11 = icmp eq ptr %10, null
+  br i1 %11, label %_llgo_7, label %_llgo_8
+
+_llgo_7:                                          ; preds = %_llgo_6
+  %12 = call ptr @"github.com/goplus/llgo/internal/runtime.Basic"(i64 58)
+  call void @"github.com/goplus/llgo/internal/runtime.SetDirectIface"(ptr %12)
+  store ptr %12, ptr @_llgo_Pointer, align 8
+  br label %_llgo_8
+
+_llgo_8:                                          ; preds = %_llgo_7, %_llgo_6
+  ret void
+}
+
+declare ptr @"github.com/goplus/llgo/internal/runtime.Basic"(i64)
+
+declare { i64, %"github.com/goplus/llgo/internal/runtime.iface" } @fmt.Printf(%"github.com/goplus/llgo/internal/runtime.String", %"github.com/goplus/llgo/internal/runtime.Slice")
+
+declare double @sin(double)
+
+declare double @cos(double)
+
+declare double @log(double)
+
+declare ptr @"github.com/goplus/llgo/internal/runtime.SliceOf"(ptr)
+
+declare ptr @"github.com/goplus/llgo/internal/runtime.CBytes"(%"github.com/goplus/llgo/internal/runtime.Slice")
+
+declare void @"github.com/goplus/llgo/internal/runtime.SetDirectIface"(ptr)
+
+declare %"github.com/goplus/llgo/internal/runtime.Slice" @"github.com/goplus/llgo/internal/runtime.GoBytes"(ptr, i64)
+
+declare [0 x i8] @free(ptr)
diff --git a/cl/compile.go b/cl/compile.go
index 7e25497c..5cbd7aa7 100644
--- a/cl/compile.go
+++ b/cl/compile.go
@@ -163,7 +163,7 @@ func (p *context) compileMethods(pkg llssa.Package, typ types.Type) {
 func (p *context) compileGlobal(pkg llssa.Package, gbl *ssa.Global) {
 	typ := globalType(gbl)
 	name, vtype, define := p.varName(gbl.Pkg.Pkg, gbl)
-	if vtype == pyVar || ignoreName(name) || checkCgo(gbl.Name()) {
+	if vtype == pyVar || ignoreName(name) || checkCgo(name) {
 		return
 	}
 	if debugInstr {
@@ -719,6 +719,10 @@ func (p *context) compileInstr(b llssa.Builder, instr ssa.Instruction) {
 	}
 	switch v := instr.(type) {
 	case *ssa.Store:
+		// skip cgo global variables
+		if checkCgo(v.Addr.Name()) {
+			return
+		}
 		va := v.Addr
 		if va, ok := va.(*ssa.IndexAddr); ok {
 			if args, ok := p.isVArgs(va.X); ok { // varargs: this is a varargs store
@@ -997,6 +1001,10 @@ func processPkg(ctx *context, ret llssa.Package, pkg *ssa.Package) {
 		case *ssa.Type:
 			ctx.compileType(ret, member)
 		case *ssa.Global:
+			// skip cgo global variables
+			if checkCgo(member.Name()) {
+				continue
+			}
 			ctx.compileGlobal(ret, member)
 		}
 	}
diff --git a/cl/import.go b/cl/import.go
index 58ae08a8..6a6a632b 100644
--- a/cl/import.go
+++ b/cl/import.go
@@ -412,6 +412,15 @@ const (
 	llgoAtomicUMax = llgoAtomicOpBase + llssa.OpUMax
 	llgoAtomicUMin = llgoAtomicOpBase + llssa.OpUMin
 
+	llgoCgoBase         = llgoInstrBase + 0x30
+	llgoCgoCString      = llgoCgoBase + 0x0
+	llgoCgoCBytes       = llgoCgoBase + 0x1
+	llgoCgoGoString     = llgoCgoBase + 0x2
+	llgoCgoGoStringN    = llgoCgoBase + 0x3
+	llgoCgoGoBytes      = llgoCgoBase + 0x4
+	llgoCgoCMalloc      = llgoCgoBase + 0x5
+	llgoCgoCheckPointer = llgoCgoBase + 0x6
+
 	llgoAtomicOpLast = llgoAtomicOpBase + int(llssa.OpUMin)
 )
 
@@ -423,6 +432,17 @@ func (p *context) funcName(fn *ssa.Function, ignore bool) (*types.Package, strin
 		p.ensureLoaded(pkg)
 		orgName = funcName(pkg, origin, true)
 	} else {
+		fname := fn.Name()
+		if fname == "_cgoCheckPointer" {
+			return nil, fname, llgoInstr
+		}
+		if strings.HasPrefix(fname, "_Cfunc_") {
+			if _, ok := llgoInstrs[fname]; ok {
+				return nil, fname, llgoInstr
+			}
+			fname = fname[7:]
+			return nil, fname, cFunc
+		}
 		if fnPkg := fn.Pkg; fnPkg != nil {
 			pkg = fnPkg.Pkg
 		} else {
diff --git a/cl/instr.go b/cl/instr.go
index ff1c30c1..93ba5ae9 100644
--- a/cl/instr.go
+++ b/cl/instr.go
@@ -66,6 +66,63 @@ func cstr(b llssa.Builder, args []ssa.Value) (ret llssa.Expr) {
 	panic("cstr(<string-literal>): invalid arguments")
 }
 
+// -----------------------------------------------------------------------------
+
+// func _Cfunc_CString(s string) *int8
+func (p *context) cgoCString(b llssa.Builder, args []ssa.Value) (ret llssa.Expr) {
+	if len(args) == 1 {
+		return b.CString(p.compileValue(b, args[0]))
+	}
+	panic("cgoCString(string): invalid arguments")
+}
+
+// func _Cfunc_CBytes(bytes []byte) *int8
+func (p *context) cgoCBytes(b llssa.Builder, args []ssa.Value) (ret llssa.Expr) {
+	if len(args) == 1 {
+		return b.CBytes(p.compileValue(b, args[0]))
+	}
+	panic("cgoCBytes([]byte): invalid arguments")
+}
+
+// func _Cfunc_GoString(s *int8) string
+func (p *context) cgoGoString(b llssa.Builder, args []ssa.Value) (ret llssa.Expr) {
+	if len(args) == 1 {
+		return b.GoString(p.compileValue(b, args[0]))
+	}
+	panic("cgoGoString(<cstr>): invalid arguments")
+}
+
+// func _Cfunc_GoStringN(s *int8, n int) string
+func (p *context) cgoGoStringN(b llssa.Builder, args []ssa.Value) (ret llssa.Expr) {
+	if len(args) == 2 {
+		return b.GoStringN(p.compileValue(b, args[0]), p.compileValue(b, args[1]))
+	}
+	panic("cgoGoStringN(<cstr>, n int): invalid arguments")
+}
+
+// func _Cfunc_GoBytes(s *int8, n int) []byte
+func (p *context) cgoGoBytes(b llssa.Builder, args []ssa.Value) (ret llssa.Expr) {
+	if len(args) == 2 {
+		return b.GoBytes(p.compileValue(b, args[0]), p.compileValue(b, args[1]))
+	}
+	panic("cgoGoBytes(<cstr>, n int): invalid arguments")
+}
+
+// func _Cfunc__CMalloc(n int) unsafe.Pointer
+func (p *context) cgoCMalloc(b llssa.Builder, args []ssa.Value) (ret llssa.Expr) {
+	if len(args) == 1 {
+		return b.CMalloc(p.compileValue(b, args[0]))
+	}
+	panic("cgoCMalloc(n int): invalid arguments")
+}
+
+// func _cgoCheckPointer(ptr any, arg any)
+func (p *context) cgoCheckPointer(b llssa.Builder, args []ssa.Value) {
+	// don't need to do anything
+}
+
+// -----------------------------------------------------------------------------
+
 // func index(arr *T, idx int) T
 func (p *context) index(b llssa.Builder, args []ssa.Value) (ret llssa.Expr) {
 	return b.Load(p.advance(b, args))
@@ -244,6 +301,14 @@ var llgoInstrs = map[string]int{
 	"atomicMin":  int(llgoAtomicMin),
 	"atomicUMax": int(llgoAtomicUMax),
 	"atomicUMin": int(llgoAtomicUMin),
+
+	"_Cfunc_CString":   llgoCgoCString,
+	"_Cfunc_CBytes":    llgoCgoCBytes,
+	"_Cfunc_GoString":  llgoCgoGoString,
+	"_Cfunc_GoStringN": llgoCgoGoStringN,
+	"_Cfunc_GoBytes":   llgoCgoGoBytes,
+	"_Cfunc__CMalloc":  llgoCgoCMalloc,
+	"_cgoCheckPointer": llgoCgoCheckPointer,
 }
 
 // funcOf returns a function by name and set ftype = goFunc, cFunc, etc.
@@ -371,6 +436,20 @@ func (p *context) call(b llssa.Builder, act llssa.DoAction, call *ssa.CallCommon
 			ret = pystr(b, args)
 		case llgoCstr:
 			ret = cstr(b, args)
+		case llgoCgoCString:
+			ret = p.cgoCString(b, args)
+		case llgoCgoCBytes:
+			ret = p.cgoCBytes(b, args)
+		case llgoCgoGoString:
+			ret = p.cgoGoString(b, args)
+		case llgoCgoGoStringN:
+			ret = p.cgoGoStringN(b, args)
+		case llgoCgoGoBytes:
+			ret = p.cgoGoBytes(b, args)
+		case llgoCgoCMalloc:
+			ret = p.cgoCMalloc(b, args)
+		case llgoCgoCheckPointer:
+			p.cgoCheckPointer(b, args)
 		case llgoAdvance:
 			ret = p.advance(b, args)
 		case llgoIndex:
@@ -407,7 +486,7 @@ func (p *context) call(b llssa.Builder, act llssa.DoAction, call *ssa.CallCommon
 			if ftype >= llgoAtomicOpBase && ftype <= llgoAtomicOpLast {
 				ret = p.atomic(b, llssa.AtomicOp(ftype-llgoAtomicOpBase), args)
 			} else {
-				log.Panicln("unknown ftype:", ftype)
+				log.Panicf("unknown ftype: %d for %s", ftype, cv.Name())
 			}
 		}
 	default:
diff --git a/internal/runtime/z_cgo.go b/internal/runtime/z_cgo.go
new file mode 100644
index 00000000..81440a93
--- /dev/null
+++ b/internal/runtime/z_cgo.go
@@ -0,0 +1,46 @@
+/*
+ * 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 runtime
+
+import (
+	"unsafe"
+
+	"github.com/goplus/llgo/c"
+)
+
+func CString(s string) *int8 {
+	p := c.Malloc(uintptr(len(s)) + 1)
+	return CStrCopy(p, *(*String)(unsafe.Pointer(&s)))
+}
+
+func CBytes(b []byte) *int8 {
+	p := c.Malloc(uintptr(len(b)))
+	c.Memcpy(p, unsafe.Pointer(&b[0]), uintptr(len(b)))
+	return (*int8)(p)
+}
+
+func GoString(p *int8) string {
+	return GoStringN(p, int(c.Strlen(p)))
+}
+
+func GoStringN(p *int8, n int) string {
+	return string((*[1 << 30]byte)(unsafe.Pointer(p))[:n:n])
+}
+
+func GoBytes(p *int8, n int) []byte {
+	return (*[1 << 30]byte)(unsafe.Pointer(p))[:n:n]
+}
diff --git a/ssa/expr.go b/ssa/expr.go
index 9dda62d2..01778fdd 100644
--- a/ssa/expr.go
+++ b/ssa/expr.go
@@ -254,6 +254,41 @@ func (b Builder) CStr(v string) Expr {
 	return Expr{llvm.CreateGlobalStringPtr(b.impl, v), b.Prog.CStr()}
 }
 
+// CString returns a c-style string
+func (b Builder) CString(v Expr) Expr {
+	fn := b.Pkg.rtFunc("CString")
+	return b.Call(fn, v)
+}
+
+// CBytes returns a c-style bytes
+func (b Builder) CBytes(v Expr) Expr {
+	fn := b.Pkg.rtFunc("CBytes")
+	return b.Call(fn, v)
+}
+
+// GoString returns a Go string
+func (b Builder) GoString(v Expr) Expr {
+	fn := b.Pkg.rtFunc("GoString")
+	return b.Call(fn, v)
+}
+
+// GoStringN returns a Go string
+func (b Builder) GoStringN(v Expr, n Expr) Expr {
+	fn := b.Pkg.rtFunc("GoStringN")
+	return b.Call(fn, v, n)
+}
+
+// GoBytes returns a Go bytes
+func (b Builder) GoBytes(v Expr, n Expr) (ret Expr) {
+	fn := b.Pkg.rtFunc("GoBytes")
+	return b.Call(fn, v, n)
+}
+
+// CMalloc returns a c-style pointer
+func (b Builder) CMalloc(n Expr) Expr {
+	return b.malloc(n)
+}
+
 // Str returns a Go string constant expression.
 func (b Builder) Str(v string) Expr {
 	prog := b.Prog
@@ -982,7 +1017,7 @@ func (b Builder) Call(fn Expr, args ...Expr) (ret Expr) {
 		bi := raw.(*builtinTy)
 		return b.BuiltinCall(bi.name, args...)
 	default:
-		log.Panicf("unreachable: %d(%T)\n", kind, raw)
+		log.Panicf("unreachable: %d(%T), %v\n", kind, raw, fn.RawType())
 	}
 	ret.Type = b.Prog.retType(sig)
 	ret.impl = llvm.CreateCall(b.impl, ll, fn.impl, llvmParamsEx(data, args, sig.Params(), b))