Commit db0d2c64 authored by Masami Hiramatsu's avatar Masami Hiramatsu Committed by Arnaldo Carvalho de Melo
Browse files

perf probe: Search concrete out-of-line instances 

gcc 4.6 generates a concrete out-of-line instance when there is a
function which is implicitly inlined somewhere but also has its own
instance. The concrete out-of-line instance means that it has an
abstract origin of the function which is referred by not only
inlined-subroutines but also a concrete subprogram.

Since current dwarf_func_inline_instances() can find only instances of
inlined-subroutines, this introduces new die_walk_instances() to find
both of subprogram and inlined-subroutines.

e.g. without this,
Available variables at sched_group_rt_period
        @<cpu_rt_period_read_uint+9>
                struct task_group*      tg

perf probe failed to find actual subprogram instance of
sched_group_rt_period().

With this,

Available variables at sched_group_rt_period
        @<cpu_rt_period_read_uint+9>
                struct task_group*      tg
        @<sched_group_rt_period+0>
                struct task_group*      tg

Now it found the sched_group_rt_period() itself.

Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: yrl.pp-manager.tt@hitachi.com
Link: http://lkml.kernel.org/r/20110811110311.19900.63997.stgit@fedora15


Signed-off-by: default avatarMasami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Signed-off-by: default avatarArnaldo Carvalho de Melo <acme@redhat.com>
parent f182e3e1

tools/perf/util/dwarf-aux.c

+58 −0
Original line number Diff line number Diff line
@@ -453,6 +453,64 @@ Dwarf_Die *die_find_inlinefunc(Dwarf_Die *sp_die, Dwarf_Addr addr, 
	return die_mem;

}



struct __instance_walk_param {

	void    *addr;

	int	(*callback)(Dwarf_Die *, void *);

	void    *data;

	int	retval;

};



static int __die_walk_instances_cb(Dwarf_Die *inst, void *data)

{

	struct __instance_walk_param *iwp = data;

	Dwarf_Attribute attr_mem;

	Dwarf_Die origin_mem;

	Dwarf_Attribute *attr;

	Dwarf_Die *origin;



	attr = dwarf_attr(inst, DW_AT_abstract_origin, &attr_mem);

	if (attr == NULL)

		return DIE_FIND_CB_CONTINUE;



	origin = dwarf_formref_die(attr, &origin_mem);

	if (origin == NULL || origin->addr != iwp->addr)

		return DIE_FIND_CB_CONTINUE;



	iwp->retval = iwp->callback(inst, iwp->data);



	return (iwp->retval) ? DIE_FIND_CB_END : DIE_FIND_CB_CONTINUE;

}



/**

 * die_walk_instances - Walk on instances of given DIE

 * @or_die: an abstract original DIE

 * @callback: a callback function which is called with instance DIE

 * @data: user data

 *

 * Walk on the instances of give @in_die. @in_die must be an inlined function

 * declartion. This returns the return value of @callback if it returns

 * non-zero value, or -ENOENT if there is no instance.

 */

int die_walk_instances(Dwarf_Die *or_die, int (*callback)(Dwarf_Die *, void *),

		       void *data)

{

	Dwarf_Die cu_die;

	Dwarf_Die die_mem;

	struct __instance_walk_param iwp = {

		.addr = or_die->addr,

		.callback = callback,

		.data = data,

		.retval = -ENOENT,

	};



	if (dwarf_diecu(or_die, &cu_die, NULL, NULL) == NULL)

		return -ENOENT;



	die_find_child(&cu_die, __die_walk_instances_cb, &iwp, &die_mem);



	return iwp.retval;

}



/* Line walker internal parameters */

struct __line_walk_param {

	bool recursive;

tools/perf/util/dwarf-aux.h

+4 −0
Original line number Diff line number Diff line
@@ -80,6 +80,10 @@ extern Dwarf_Die *die_find_realfunc(Dwarf_Die *cu_die, Dwarf_Addr addr, 
extern Dwarf_Die *die_find_inlinefunc(Dwarf_Die *sp_die, Dwarf_Addr addr,

				      Dwarf_Die *die_mem);



/* Walk on the instances of given DIE */

extern int die_walk_instances(Dwarf_Die *in_die,

			      int (*callback)(Dwarf_Die *, void *), void *data);



/* Walker on lines (Note: line number will not be sorted) */

typedef int (* line_walk_callback_t) (const char *fname, int lineno,

				      Dwarf_Addr addr, void *data);

tools/perf/util/probe-finder.c

+21 −35
Original line number Diff line number Diff line
@@ -924,42 +924,39 @@ static int find_probe_point_lazy(Dwarf_Die *sp_die, struct probe_finder *pf) 
	return die_walk_lines(sp_die, probe_point_lazy_walker, pf);

}



/* Callback parameter with return value */

struct dwarf_callback_param {

	void *data;

	int retval;

};



static int probe_point_inline_cb(Dwarf_Die *in_die, void *data)

{

	struct dwarf_callback_param *param = data;

	struct probe_finder *pf = param->data;

	struct probe_finder *pf = data;

	struct perf_probe_point *pp = &pf->pev->point;

	Dwarf_Addr addr;

	int ret;



	if (pp->lazy_line)

		param->retval = find_probe_point_lazy(in_die, pf);

		ret = find_probe_point_lazy(in_die, pf);

	else {

		/* Get probe address */

		if (dwarf_entrypc(in_die, &addr) != 0) {

			pr_warning("Failed to get entry address of %s.\n",

				   dwarf_diename(in_die));

			param->retval = -ENOENT;

			return DWARF_CB_ABORT;

			return -ENOENT;

		}

		pf->addr = addr;

		pf->addr += pp->offset;

		pr_debug("found inline addr: 0x%jx\n",

			 (uintmax_t)pf->addr);



		param->retval = call_probe_finder(in_die, pf);

		if (param->retval < 0)

			return DWARF_CB_ABORT;

		ret = call_probe_finder(in_die, pf);

	}



	return DWARF_CB_OK;

	return ret;

}



/* Callback parameter with return value for libdw */

struct dwarf_callback_param {

	void *data;

	int retval;

};



/* Search function from function name */

static int probe_point_search_cb(Dwarf_Die *sp_die, void *data)

{
@@ -996,14 +993,10 @@ static int probe_point_search_cb(Dwarf_Die *sp_die, void *data) 
			/* TODO: Check the address in this function */

			param->retval = call_probe_finder(sp_die, pf);

		}

	} else {

		struct dwarf_callback_param _param = {.data = (void *)pf,

						      .retval = 0};

	} else

		/* Inlined function: search instances */

		dwarf_func_inline_instances(sp_die, probe_point_inline_cb,

					    &_param);

		param->retval = _param.retval;

	}

		param->retval = die_walk_instances(sp_die,

					probe_point_inline_cb, (void *)pf);



	return DWARF_CB_ABORT; /* Exit; no same symbol in this CU. */

}
@@ -1452,16 +1445,14 @@ static int find_line_range_by_line(Dwarf_Die *sp_die, struct line_finder *lf) 


static int line_range_inline_cb(Dwarf_Die *in_die, void *data)

{

	struct dwarf_callback_param *param = data;



	param->retval = find_line_range_by_line(in_die, param->data);

	find_line_range_by_line(in_die, data);



	/*

	 * We have to check all instances of inlined function, because

	 * some execution paths can be optimized out depends on the

	 * function argument of instances

	 */

	return DWARF_CB_OK;

	return 0;

}



/* Search function from function name */
@@ -1489,15 +1480,10 @@ static int line_range_search_cb(Dwarf_Die *sp_die, void *data) 
		pr_debug("New line range: %d to %d\n", lf->lno_s, lf->lno_e);

		lr->start = lf->lno_s;

		lr->end = lf->lno_e;

		if (dwarf_func_inline(sp_die)) {

			struct dwarf_callback_param _param;

			_param.data = (void *)lf;

			_param.retval = 0;

			dwarf_func_inline_instances(sp_die,

						    line_range_inline_cb,

						    &_param);

			param->retval = _param.retval;

		} else

		if (dwarf_func_inline(sp_die))

			param->retval = die_walk_instances(sp_die,

						line_range_inline_cb, lf);

		else

			param->retval = find_line_range_by_line(sp_die, lf);

		return DWARF_CB_ABORT;

	}

CRA Git | Maintained and supported by SUSTech CRA and CCSE