Re: [PATCH 1/4] perf tools: add Java demangling support

[Namhyung Kim <namhyung@kernel.org>]

On Wed, Feb 11, 2015 at 12:42:42AM +0100, Stephane Eranian wrote:
> Add Java function descriptor demangling support.
> Something bfd cannot do.
> 
> Signed-off-by: Stephane Eranian <eranian@google.com>
> ---

[SNIP]
> +/*
> + * Demangle Java function signature (Hotspot, not GCJ)
> + * input:
> + * 	str: string to parse. String is not modified
> + * return:
> + *	if can demangle then a a newly allocate string is returned.
> + *	if cannot demangle, then NULL is returned
> + *
> + * Note that caller is responsible for freeing demangled string
> + */
> +char *
> +java_demangle_sym(const char *str)
> +{
> +	char *buf, *ptr;
> +	char *p;
> +	size_t len, l1;
> +
> +	if (!str)
> +		return NULL;
> +
> +	/* find start of retunr type */
> +	p = strrchr(str, ')');
> +	if (!p)
> +		return NULL;
> +
> +	/*
> +	 * expansion factor estimated to 3x
> +	 */
> +	len = strlen(str) * 3 + 1;
> +	buf = malloc(len);
> +	if (!buf)
> +		return NULL;
> +
> +	buf[0] = '\0';
> +	/*
> +	 * get return type first
> +	 */
> +	ptr = __demangle_java_sym(p+1, NULL, buf, len, MODE_TYPE);
> +	if (!ptr)
> +		goto error;
> +
> +	/* add space between return type and function prototype */
> +	l1 = strlen(buf);
> +	buf[l1++] = ' ';
> +
> +	/* process function up to return type */
> +	ptr = __demangle_java_sym(str, p + 1, buf + l1, len - l1, MODE_PREFIX);
> +	if (!ptr)
> +		goto error;

Do we really need to use return type for Java symbol name?  Note that
for C++ demangling, we show function name only by default and
parameters will be shown when user gave -v option.

Thanks,
Namhyung


> +
> +	return buf;
> +error:
> +	free(buf);
> +	return NULL;
> +}
> +
> +