Re: [PATCH v2] pahole: Add --kabi_prefix flag

[Jiri Olsa <jolsa@redhat.com>]

On Wed, May 19, 2021 at 10:44:44AM +0800, Shuyi Cheng wrote:

SNIP

> where
>  one wants to know what if the installed version has some feature, i.e.: 118
> instead of "v1.18".
> 
> +.TP
> +.B \-\-kabi_prefix=STRING
> +When the prefix of the string is STRING, treat the string as STRING.
> +
>  .SH NOTES
> 
>  To enable the generation of debugging information in the Linux kernel build
> diff --git a/pahole.c b/pahole.c
> index dc40ccf..6a700d9 100644
> --- a/pahole.c
> +++ b/pahole.c
> @@ -24,6 +24,7 @@
>  #include "btf_encoder.h"
>  #include "libbtf.h"
>  #include "lib/bpf/src/libbpf.h"
> +#include "pahole_strings.h"
> 
>  static bool btf_encode;
>  static bool ctf_encode;
> @@ -855,6 +856,7 @@ ARGP_PROGRAM_VERSION_HOOK_DEF = dwarves_print_version;
>  #define ARGP_btf_gen_floats	   322
>  #define ARGP_btf_gen_all	   323
>  #define ARGP_with_flexible_array   324
> +#define ARGP_kabi_prefix   325
> 
>  static const struct argp_option pahole__options[] = {
>  	{
> @@ -1140,6 +1142,12 @@ static const struct argp_option pahole__options[] = {
>  		.doc  = "Path to the base BTF file",
>  	},
>  	{
> +		.name = "kabi_prefix",
> +		.key = ARGP_kabi_prefix,
> +		.arg = "STRING",
> +		.doc = "When the prefix of the string is STRING, treat the string as
> STRING.",

please keep the '=' indentation


> +	},
> +	{
>  		.name = "btf_encode",
>  		.key  = 'J',
>  		.doc  = "Encode as BTF",
> @@ -1297,6 +1305,8 @@ static error_t pahole__options_parser(int key, char
> *arg,
>  		btf_encode_force = true;		break;
>  	case ARGP_btf_base:
>  		base_btf_file = arg;			break;
> +	case ARGP_kabi_prefix:
> +		kabi_prefix = arg;		break;
>  	case ARGP_numeric_version:
>  		print_numeric_version = true;		break;
>  	case ARGP_btf_gen_floats:
> diff --git a/pahole_strings.h b/pahole_strings.h
> index 522fbf2..a836ba8 100644
> --- a/pahole_strings.h
> +++ b/pahole_strings.h
> @@ -14,6 +14,8 @@ struct strings {
>  	struct btf *btf;
>  };
> 
> +extern const char *kabi_prefix;
> +
>  struct strings *strings__new(void);
> 
>  void strings__delete(struct strings *strings);
> diff --git a/strings.c b/strings.c
> index d37f49d..d1a54ec 100644
> --- a/strings.c
> +++ b/strings.c
> @@ -17,6 +17,8 @@
>  #include "dutil.h"
>  #include "lib/bpf/src/libbpf.h"
> 
> +const char *kabi_prefix;
> +
>  struct strings *strings__new(void)
>  {
>  	struct strings *strs = malloc(sizeof(*strs));
> @@ -48,7 +50,12 @@ strings_t strings__add(struct strings *strs, const char
> *str)
>  	if (str == NULL)
>  		return 0;
> 
> -	index = btf__add_str(strs->btf, str);
> +	if (kabi_prefix &&
> +		strncmp(str, kabi_prefix, strlen(kabi_prefix)) == 0)
> +		index = btf__add_str(strs->btf, kabi_prefix);
> +	else
> +		index = btf__add_str(strs->btf, str);
> +		

^^^ extra whitespace, other than that looks ok

Acked-by: Jiri Olsa <jolsa@redhat.com>

jirka

>  	if (index < 0)
>  		return 0;
> 
> -- 
> 1.8.3.1
>