Re: [PATCH v2 12/20] disas/nanomips: Replace std::string type

[Richard Henderson]

On 9/5/22 10:55, Milica Lazarevic wrote:
> -static std::string save_restore_list(uint64 rt, uint64 count, uint64 gp)
> +static char *save_restore_list(uint64 rt, uint64 count, uint64 gp)
>   {
> -    std::string str;
> +    /*
> +     * Currently, this file compiles as a cpp file, so the explicit cast here
> +     * is necessary. Later, the cast will be removed.
> +     */
> +    char *str = (char *)g_malloc(200);
> +    str[0] = '\0';
>   
>       for (uint64 counter = 0; counter != count; counter++) {
>           bool use_gp = gp && (counter == count - 1);
>           uint64 this_rt = use_gp ? 28 : ((rt & 0x10) | (rt + counter)) & 0x1f;
> -        str += img_format(",%s", GPR(this_rt));
> +        strcat(str, img_format(",%s", GPR(this_rt)));
>       }
>   
>       return str;
>   }

This would be better written as

    char *reg_list[33];

    assert(count <= 32);
    for (c = 0; c < count; c++) {
        bool use_gp = ...
        uint64 this_rt = ...
        /* glib usage below requires casting away const */
        reg_list[c] = (char *)GPR(this_rt);
    }
    reg_list[count] = NULL;

    return g_strjoinv(",", reg_list);



> @@ -716,7 +617,7 @@ static uint64 extract_op_code_value(const uint16 *data, int 
> size)
>    *      instruction size    - negative is error
>    *      disassembly string  - on error will constain error string
>    */
> -static int Disassemble(const uint16 *data, std::string & dis,
> +static int Disassemble(const uint16 *data, char *dis,


I think this interface should be

    char **dis,

so that...

> @@ -746,25 +647,26 @@ static int Disassemble(const uint16 *data, std::string & 
> dis,
>                                    * an ASE attribute and the requested version
>                                    * not having that attribute
>                                    */
> -                                dis = "ASE attribute mismatch";
> +                                strcpy(dis, "ASE attribute mismatch");

these become

    *dis = g_strdup("string");

and the usage in nanomips_dis does not assume a fixed sized buffer.


r~