Re: Re: [PATCH v2] perf probe: Find compilation directory path for lazy matching

[Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>]

(2015/03/11 22:30), Arnaldo Carvalho de Melo wrote:
> Em Wed, Mar 04, 2015 at 09:34:38PM +0900, Masami Hiramatsu escreveu:
>> (2015/03/04 16:52), Naohiro Aota wrote:
>>> If we use lazy matching, it failed to open a souce file if perf command
>>> is invoked outside of compilation directory:
>>>
>>> $ perf probe -a '__schedule;clear_*'
>>> Failed to open kernel/sched/core.c: No such file or directory
>>>   Error: Failed to add events. (-2)
>>>
>>> OTOH, other commands like "probe -L" can solve the souce directory by
>>> themselves. Let's make it possible for lazy matching too!
>>>
>>
>> Looks good to me :)
>>
>> Acked-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
> 
> This doesn't make sense... se below:
>  
>> Thank you!
>>
>>> diff --git a/tools/perf/util/probe-finder.c b/tools/perf/util/probe-finder.c
>>> index 46f009a..e6c0262 100644
>>> --- a/tools/perf/util/probe-finder.c
>>> +++ b/tools/perf/util/probe-finder.c
>>> @@ -849,11 +849,22 @@ static int probe_point_lazy_walker(const char *fname, int lineno,
>>>  static int find_probe_point_lazy(Dwarf_Die *sp_die, struct probe_finder *pf)
>>>  {
>>>  	int ret = 0;
>>> +	char *fpath;
>>>  
>>>  	if (intlist__empty(pf->lcache)) {
>>> +		const char *comp_dir;
>>> +
>>> +		comp_dir = cu_get_comp_dir(&pf->cu_die);
>>> +		ret = get_real_path(pf->fname, comp_dir, &fpath);
>>> +		if (ret < 0) {
>>> +			pr_warning("Failed to find source file path.\n");
>>> +			return ret;
>>> +		}
>>> +
>>>  		/* Matching lazy line pattern */
>>> -		ret = find_lazy_match_lines(pf->lcache, pf->fname,
>>> +		ret = find_lazy_match_lines(pf->lcache, fpath,
>>>  					    pf->pev->point.lazy_line);
>>> +		free(fpath);
>>>  		if (ret <= 0)
>>>  			return ret;
>>>  	}
>>> @@ -1616,3 +1627,61 @@ found:
>>>  	return (ret < 0) ? ret : lf.found;
>>>  }
>>>  
>>> +/*
>>> + * Find a src file from a DWARF tag path. Prepend optional source path prefix
>>> + * and chop off leading directories that do not exist. Result is passed back as
>>> + * a newly allocated path on success.
>>> + * Return 0 if file was found and readable, -errno otherwise.
>>> + */
>>> +static int get_real_path(const char *raw_path, const char *comp_dir,
>>> +			 char **new_path)
> 
> The function is marked "static"
> 
>>> +{
>>> +	const char *prefix = symbol_conf.source_prefix;
>>> +
>>> +	if (!prefix) {
>>> +		if (raw_path[0] != '/' && comp_dir)
>>> +			/* If not an absolute path, try to use comp_dir */
>>> +			prefix = comp_dir;
>>> +		else {
>>> +			if (access(raw_path, R_OK) == 0) {
>>> +				*new_path = strdup(raw_path);
>>> +				return *new_path ? 0 : -ENOMEM;
>>> +			} else
>>> +				return -errno;
>>> +		}
>>> +	}
>>> +
>>> +	*new_path = malloc((strlen(prefix) + strlen(raw_path) + 2));
>>> +	if (!*new_path)
>>> +		return -ENOMEM;
>>> +
>>> +	for (;;) {
>>> +		sprintf(*new_path, "%s/%s", prefix, raw_path);
>>> +
>>> +		if (access(*new_path, R_OK) == 0)
>>> +			return 0;
>>> +
>>> +		if (!symbol_conf.source_prefix) {
>>> +			/* In case of searching comp_dir, don't retry */
>>> +			zfree(new_path);
>>> +			return -errno;
>>> +		}
>>> +
>>> +		switch (errno) {
>>> +		case ENAMETOOLONG:
>>> +		case ENOENT:
>>> +		case EROFS:
>>> +		case EFAULT:
>>> +			raw_path = strchr(++raw_path, '/');
>>> +			if (!raw_path) {
>>> +				zfree(new_path);
>>> +				return -ENOENT;
>>> +			}
>>> +			continue;
>>> +
>>> +		default:
>>> +			zfree(new_path);
>>> +			return -errno;
>>> +		}
>>> +	}
>>> +}
>>> diff --git a/tools/perf/util/probe-finder.h b/tools/perf/util/probe-finder.h
>>> index 92590b2..5ef82dd 100644
>>> --- a/tools/perf/util/probe-finder.h
>>> +++ b/tools/perf/util/probe-finder.h
>>> @@ -55,6 +55,10 @@ extern int debuginfo__find_available_vars_at(struct debuginfo *dbg,
>>>  					     struct variable_list **vls,
>>>  					     int max_points, bool externs);
>>>  
>>> +/* Find a src file from a DWARF tag path */
>>> +extern int get_real_path(const char *raw_path, const char *comp_dir,
>>> +			 char **new_path);
>>> +
> 
> And then you mark it "extern"? Have you tried to compile this? I tried:
>  
>   CC       /tmp/build/perf/tests/task-exit.o
> util/probe-finder.c:1636:12: error: static declaration of ‘get_real_path’ follows non-static declaration
>  static int get_real_path(const char *raw_path, const char *comp_dir,
>             ^
> In file included from util/probe-finder.c:41:0:
> util/probe-finder.h:59:12: note: previous declaration of ‘get_real_path’ was here
>  extern int get_real_path(const char *raw_path, const char *comp_dir,
>             ^
> util/probe-finder.c:1636:12: error: ‘get_real_path’ defined but not used [-Werror=unused-function]
>  static int get_real_path(const char *raw_path, const char *comp_dir,
>             ^
> cc1: all warnings being treated as errors
> make[3]: *** [/tmp/build/perf/util/probe-finder.o] Error 1
> make[3]: *** Waiting for unfinished jobs....
>   CC       /tmp/build/perf/tests/sw-clock.o
> 
> Also please refrain from using 'extern' in front of function prototypes, its just noise.1

Ooops! Sorry, I missed this ...

Naohiro, could you fix this?

Thanks,

> 
> - Arnaldo
> 
>>>  struct probe_finder {
>>>  	struct perf_probe_event	*pev;		/* Target probe event */
>>>  
>>>
>>
>>
>> -- 
>> Masami HIRAMATSU
>> Software Platform Research Dept. Linux Technology Research Center
>> Hitachi, Ltd., Yokohama Research Laboratory
>> E-mail: masami.hiramatsu.pt@hitachi.com
>>
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-- 
Masami HIRAMATSU
Software Platform Research Dept. Linux Technology Research Center
Hitachi, Ltd., Yokohama Research Laboratory
E-mail: masami.hiramatsu.pt@hitachi.com