Hi team

I had a function trace demo with Struct parameter and Struct return, but got the "cannot handle offset into register" error.

my environments:
  os: Ubuntu 16.04 LTS
  gcc 8.3
  systemtap 4.5
  elfutils 0.185


# func.h
struct DataPackage {
    int len;
    float width;
    // float width2; // uncomment this line will work :)
    double angle;
};

struct DataPackage func_complex_v2(struct DataPackage input_data, int page);

# func.c

struct DataPackage func_complex_v2(struct DataPackage input_data, int page) {
    struct DataPackage d;
    d.len = 19;
    d.width = 115.33;
    d.angle = 6.66;

    return d;
}

# main.c
int main(int argc, char const *argv[])
{

    struct DataPackage d;
    d.len = 997;
    d.width = 10;
    d.angle = 0.777;

    struct DataPackage r =func_complex_v2(d, 789);

    return 0;
}

# cc_stap_test_complex.stp
probe process("/home/xyz/vs_workspace/CacheLab/build/test").function("func_complex_v2").return {
    printf("func_complex_v2 return: %s\n", fp_to_string($return->width, 6))
}


Here is the console output:

Debug translate_offsetsemantic error: cannot handle offset into register: identifier '$return' at 
/home/xyz/cc_stap_test_complex.stp:73:57
        source:     printf("func_complex_v2 return: %s\n", fp_to_string($return->width, 6))
                                                                        ^

semantic error: unresolved type : identifier '$return' at :73:57
        source:     printf("func_complex_v2 return: %s\n", fp_to_string($return->width, 6))


Any advice is appreciate, thanks!