Re: [PATCH 4/5] perf annotate: don't pipe objdump output through expand

From: Arnaldo Carvalho de Melo <arnaldo.melo@gmail.com>
To: Ian Rogers <irogers@google.com>
Cc: Peter Zijlstra <peterz@infradead.org>,
	Ingo Molnar <mingo@redhat.com>,
	Mark Rutland <mark.rutland@arm.com>,
	Alexander Shishkin <alexander.shishkin@linux.intel.com>,
	Jiri Olsa <jolsa@redhat.com>, Namhyung Kim <namhyung@kernel.org>,
	Jin Yao <yao.jin@linux.intel.com>,
	Song Liu <songliubraving@fb.com>,
	linux-kernel@vger.kernel.org, clang-built-linux@googlegroups.com,
	Stephane Eranian <eranian@google.com>
Subject: Re: [PATCH 4/5] perf annotate: don't pipe objdump output through expand
Date: Mon, 14 Oct 2019 11:24:36 -0300	[thread overview]
Message-ID: <20191014142436.GJ19627@kernel.org> (raw)
In-Reply-To: <20191010183649.23768-5-irogers@google.com>

Em Thu, Oct 10, 2019 at 11:36:48AM -0700, Ian Rogers escreveu:
> Avoiding a pipe allows objdump command failures to surface.
> Move to the caller of symbol__parse_objdump_line the call to strim
> that removes leading and trailing tabs.
> Add a new expand_tabs function that if a tab is present allocate a new
> line in which tabs are expanded.
> In symbol__parse_objdump_line the line had no leading spaces, so
> simplify the line_ip processing.

Thanks, applied.

> Signed-off-by: Ian Rogers <irogers@google.com>
> ---
>  tools/perf/util/annotate.c | 95 ++++++++++++++++++++++++++++++--------
>  1 file changed, 76 insertions(+), 19 deletions(-)
> 
> diff --git a/tools/perf/util/annotate.c b/tools/perf/util/annotate.c
> index 0a7a6f3c55f4..3d5b9236576a 100644
> --- a/tools/perf/util/annotate.c
> +++ b/tools/perf/util/annotate.c
> @@ -1488,35 +1488,24 @@ annotation_line__print(struct annotation_line *al, struct symbol *sym, u64 start
>   */
>  static int symbol__parse_objdump_line(struct symbol *sym,
>  				      struct annotate_args *args,
> -				      char *line, int *line_nr)
> +				      char *parsed_line, int *line_nr)
>  {
>  	struct map *map = args->ms.map;
>  	struct annotation *notes = symbol__annotation(sym);
>  	struct disasm_line *dl;
> -	char *parsed_line, *tmp, *tmp2;
> +	char *tmp;
>  	s64 line_ip, offset = -1;
>  	regmatch_t match[2];
>  
> -	line_ip = -1;
> -	parsed_line = strim(line);
> -
>  	/* /filename:linenr ? Save line number and ignore. */
>  	if (regexec(&file_lineno, parsed_line, 2, match, 0) == 0) {
>  		*line_nr = atoi(parsed_line + match[1].rm_so);
>  		return 0;
>  	}
>  
> -	tmp = skip_spaces(parsed_line);
> -	if (*tmp) {
> -		/*
> -		 * Parse hexa addresses followed by ':'
> -		 */
> -		line_ip = strtoull(tmp, &tmp2, 16);
> -		if (*tmp2 != ':' || tmp == tmp2 || tmp2[1] == '\0')
> -			line_ip = -1;
> -	}
> -
> -	if (line_ip != -1) {
> +	/* Process hex address followed by ':'. */
> +	line_ip = strtoull(parsed_line, &tmp, 16);
> +	if (parsed_line != tmp && tmp[0] == ':' && tmp[1] != '\0') {
>  		u64 start = map__rip_2objdump(map, sym->start),
>  		    end = map__rip_2objdump(map, sym->end);
>  
> @@ -1524,7 +1513,7 @@ static int symbol__parse_objdump_line(struct symbol *sym,
>  		if ((u64)line_ip < start || (u64)line_ip >= end)
>  			offset = -1;
>  		else
> -			parsed_line = tmp2 + 1;
> +			parsed_line = tmp + 1;
>  	}
>  
>  	args->offset  = offset;
> @@ -1833,6 +1822,67 @@ static int symbol__disassemble_bpf(struct symbol *sym __maybe_unused,
>  }
>  #endif // defined(HAVE_LIBBFD_SUPPORT) && defined(HAVE_LIBBPF_SUPPORT)
>  
> +/*
> + * Possibly create a new version of line with tabs expanded. Returns the
> + * existing or new line, storage is updated if a new line is allocated. If
> + * allocation fails then NULL is returned.
> + */
> +static char *expand_tabs(char *line, char **storage, size_t *storage_len)
> +{
> +	size_t i, src, dst, len, new_storage_len, num_tabs;
> +	char *new_line;
> +	size_t line_len = strlen(line);
> +
> +	for (num_tabs = 0, i = 0; i < line_len; i++)
> +		if (line[i] == '\t')
> +			num_tabs++;
> +
> +	if (num_tabs == 0)
> +		return line;
> +
> +	/*
> +	 * Space for the line and '\0', less the leading and trailing
> +	 * spaces. Each tab may introduce 7 additional spaces.
> +	 */
> +	new_storage_len = line_len + 1 + (num_tabs * 7);
> +
> +	new_line = malloc(new_storage_len);
> +	if (new_line == NULL) {
> +		pr_err("Failure allocating memory for tab expansion\n");
> +		return NULL;
> +	}
> +
> +	/*
> +	 * Copy regions starting at src and expand tabs. If there are two
> +	 * adjacent tabs then 'src == i', the memcpy is of size 0 and the spaces
> +	 * are inserted.
> +	 */
> +	for (i = 0, src = 0, dst = 0; i < line_len && num_tabs; i++) {
> +		if (line[i] == '\t') {
> +			len = i - src;
> +			memcpy(&new_line[dst], &line[src], len);
> +			dst += len;
> +			new_line[dst++] = ' ';
> +			while (dst % 8 != 0)
> +				new_line[dst++] = ' ';
> +			src = i + 1;
> +			num_tabs--;
> +		}
> +	}
> +
> +	/* Expand the last region. */
> +	len = line_len + 1 - src;
> +	memcpy(&new_line[dst], &line[src], len);
> +	dst += len;
> +	new_line[dst] = '\0';
> +
> +	free(*storage);
> +	*storage = new_line;
> +	*storage_len = new_storage_len;
> +	return new_line;
> +
> +}
> +
>  static int symbol__disassemble(struct symbol *sym, struct annotate_args *args)
>  {
>  	struct annotation_options *opts = args->options;
> @@ -1894,7 +1944,7 @@ static int symbol__disassemble(struct symbol *sym, struct annotate_args *args)
>  	err = asprintf(&command,
>  		 "%s %s%s --start-address=0x%016" PRIx64
>  		 " --stop-address=0x%016" PRIx64
> -		 " -l -d %s %s -C \"$1\" 2>/dev/null|expand",
> +		 " -l -d %s %s -C \"$1\" 2>/dev/null",
>  		 opts->objdump_path ?: "objdump",
>  		 opts->disassembler_style ? "-M " : "",
>  		 opts->disassembler_style ?: "",
> @@ -1941,6 +1991,7 @@ static int symbol__disassemble(struct symbol *sym, struct annotate_args *args)
>  	nline = 0;
>  	while (!feof(file)) {
>  		const char *match;
> +		char *expanded_line;
>  
>  		if (getline(&line, &line_len, file) < 0 || !line)
>  			break;
> @@ -1950,13 +2001,19 @@ static int symbol__disassemble(struct symbol *sym, struct annotate_args *args)
>  		if (match && match[strlen(symfs_filename)] == ':')
>  			continue;
>  
> +		expanded_line = strim(line);
> +		expanded_line = expand_tabs(expanded_line, &line, &line_len);
> +		if (!expanded_line)
> +			break;
> +
>  		/*
>  		 * The source code line number (lineno) needs to be kept in
>  		 * across calls to symbol__parse_objdump_line(), so that it
>  		 * can associate it with the instructions till the next one.
>  		 * See disasm_line__new() and struct disasm_line::line_nr.
>  		 */
> -		if (symbol__parse_objdump_line(sym, args, line, &lineno) < 0)
> +		if (symbol__parse_objdump_line(sym, args, expanded_line,
> +					       &lineno) < 0)
>  			break;
>  		nline++;
>  	}
> -- 
> 2.23.0.581.g78d2f28ef7-goog

-- 

- Arnaldo