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Commit b0ef0732 authored by Masami Hiramatsu's avatar Masami Hiramatsu Committed by Ingo Molnar
Browse files

perf/probes: Support function entry relative line number 



Add function-entry relative line number specifying support to
perf-probe. This allows users to define probes by line number
from entry of the function.

 e.g.

  perf probe schedule:16

Signed-off-by: default avatarMasami Hiramatsu <mhiramat@redhat.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Jim Keniston <jkenisto@us.ibm.com>
Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Frank Ch. Eigler <fche@redhat.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Jason Baron <jbaron@redhat.com>
Cc: K.Prasad <prasad@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
LKML-Reference: <20091027204319.30545.30678.stgit@harusame>
Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
parent 253977b0

tools/perf/builtin-probe.c

+7 −7
Original line number Diff line number Diff line
@@ -133,17 +133,16 @@ static void parse_probe_point(char *arg, struct probe_point *pp) 
	}



	/* Exclusion check */

	if (pp->line && pp->function)

		semantic_error("Function-relative line number is not"

				" supported yet.");

	if (pp->line && pp->offset)

		semantic_error("Offset can't be used with line number.");

	if (!pp->line && pp->file && !pp->function)

		semantic_error("File always requires line number.");

	if (pp->offset && !pp->function)

		semantic_error("Offset requires an entry function.");

	if (pp->retprobe && !pp->function)

		semantic_error("Return probe requires an entry function.");

	if (pp->offset && pp->retprobe)

		semantic_error("Offset can't be used with return probe.");

	if ((pp->offset || pp->line) && pp->retprobe)

		semantic_error("Offset/Line can't be used with return probe.");



	pr_debug("symbol:%s file:%s line:%d offset:%d, return:%d\n",

		 pp->function, pp->file, pp->line, pp->offset, pp->retprobe);
@@ -270,7 +269,7 @@ static const struct option options[] = { 
#ifdef NO_LIBDWARF

		"FUNC[+OFFS|%return] [ARG ...]",

#else

		"FUNC[+OFFS|%return][@SRC]|SRC:LINE [ARG ...]",

		"FUNC[+OFFS|%return|:RLN][@SRC]|SRC:ALN [ARG ...]",

#endif

		"probe point definition, where\n"

		"\t\tGRP:\tGroup name (optional)\n"
@@ -282,7 +281,8 @@ static const struct option options[] = { 
		"\t\tARG:\tProbe argument (only \n"

#else

		"\t\tSRC:\tSource code path\n"

		"\t\tLINE:\tLine number\n"

		"\t\tRLN:\tRelative line number from function entry.\n"

		"\t\tALN:\tAbsolute line number in file.\n"

		"\t\tARG:\tProbe argument (local variable name or\n"

#endif

		"\t\t\tkprobe-tracer argument format is supported.)\n",

tools/perf/util/probe-finder.c

+61 −18
Original line number Diff line number Diff line
@@ -114,7 +114,7 @@ static int strtailcmp(const char *s1, const char *s2) 
}



/* Find the fileno of the target file. */

static Dwarf_Unsigned die_get_fileno(Dwarf_Die cu_die, const char *fname)

static Dwarf_Unsigned cu_find_fileno(Dwarf_Die cu_die, const char *fname)

{

	Dwarf_Signed cnt, i;

	Dwarf_Unsigned found = 0;
@@ -335,6 +335,36 @@ static int attr_get_locdesc(Dwarf_Attribute attr, Dwarf_Locdesc *desc, 
	return ret;

}



/* Get decl_file attribute value (file number) */

static Dwarf_Unsigned die_get_decl_file(Dwarf_Die sp_die)

{

	Dwarf_Attribute attr;

	Dwarf_Unsigned fno;

	int ret;



	ret = dwarf_attr(sp_die, DW_AT_decl_file, &attr, &__dw_error);

	DIE_IF(ret != DW_DLV_OK);

	dwarf_formudata(attr, &fno, &__dw_error);

	DIE_IF(ret != DW_DLV_OK);

	dwarf_dealloc(__dw_debug, attr, DW_DLA_ATTR);

	return fno;

}



/* Get decl_line attribute value (line number) */

static Dwarf_Unsigned die_get_decl_line(Dwarf_Die sp_die)

{

	Dwarf_Attribute attr;

	Dwarf_Unsigned lno;

	int ret;



	ret = dwarf_attr(sp_die, DW_AT_decl_line, &attr, &__dw_error);

	DIE_IF(ret != DW_DLV_OK);

	dwarf_formudata(attr, &lno, &__dw_error);

	DIE_IF(ret != DW_DLV_OK);

	dwarf_dealloc(__dw_debug, attr, DW_DLA_ATTR);

	return lno;

}



/*

 * Probe finder related functions

 */
@@ -501,6 +531,7 @@ static void show_probepoint(Dwarf_Die sp_die, Dwarf_Signed offs, 
	DIE_IF(ret < 0);

	DIE_IF(ret >= MAX_PROBE_BUFFER);

	len = ret;

	pr_debug("Probe point found: %s\n", tmp);



	/* Find each argument */

	get_current_frame_base(sp_die, pf);
@@ -536,17 +567,16 @@ static int probeaddr_callback(struct die_link *dlink, void *data) 
}



/* Find probe point from its line number */

static void find_by_line(Dwarf_Die cu_die, struct probe_finder *pf)

static void find_by_line(struct probe_finder *pf)

{

	struct probe_point *pp = pf->pp;

	Dwarf_Signed cnt, i;

	Dwarf_Signed cnt, i, clm;

	Dwarf_Line *lines;

	Dwarf_Unsigned lineno = 0;

	Dwarf_Addr addr;

	Dwarf_Unsigned fno;

	int ret;



	ret = dwarf_srclines(cu_die, &lines, &cnt, &__dw_error);

	ret = dwarf_srclines(pf->cu_die, &lines, &cnt, &__dw_error);

	DIE_IF(ret != DW_DLV_OK);



	for (i = 0; i < cnt; i++) {
@@ -557,15 +587,20 @@ static void find_by_line(Dwarf_Die cu_die, struct probe_finder *pf) 


		ret = dwarf_lineno(lines[i], &lineno, &__dw_error);

		DIE_IF(ret != DW_DLV_OK);

		if (lineno != (Dwarf_Unsigned)pp->line)

		if (lineno != pf->lno)

			continue;



		ret = dwarf_lineoff(lines[i], &clm, &__dw_error);

		DIE_IF(ret != DW_DLV_OK);



		ret = dwarf_lineaddr(lines[i], &addr, &__dw_error);

		DIE_IF(ret != DW_DLV_OK);

		pr_debug("Probe point found: 0x%llx\n", addr);

		pr_debug("Probe line found: line[%d]:%u,%d addr:0x%llx\n",

			 (int)i, (unsigned)lineno, (int)clm, addr);

		pf->addr = addr;

		/* Search a real subprogram including this line, */

		ret = search_die_from_children(cu_die, probeaddr_callback, pf);

		ret = search_die_from_children(pf->cu_die,

					       probeaddr_callback, pf);

		if (ret == 0)

			die("Probe point is not found in subprograms.\n");

		/* Continuing, because target line might be inlined. */
@@ -587,6 +622,13 @@ static int probefunc_callback(struct die_link *dlink, void *data) 
	DIE_IF(ret == DW_DLV_ERROR);

	if (tag == DW_TAG_subprogram) {

		if (die_compare_name(dlink->die, pp->function) == 0) {

			if (pp->line) {	/* Function relative line */

				pf->fno = die_get_decl_file(dlink->die);

				pf->lno = die_get_decl_line(dlink->die)

					 + pp->line;

				find_by_line(pf);

				return 1;

			}

			if (die_inlined_subprogram(dlink->die)) {

				/* Inlined function, save it. */

				ret = dwarf_die_CU_offset(dlink->die,
@@ -631,9 +673,9 @@ static int probefunc_callback(struct die_link *dlink, void *data) 
	return 0;

}



static void find_by_func(Dwarf_Die cu_die, struct probe_finder *pf)

static void find_by_func(struct probe_finder *pf)

{

	search_die_from_children(cu_die, probefunc_callback, pf);

	search_die_from_children(pf->cu_die, probefunc_callback, pf);

}



/* Find a probe point */
@@ -641,7 +683,6 @@ int find_probepoint(int fd, struct probe_point *pp) 
{

	Dwarf_Half addr_size = 0;

	Dwarf_Unsigned next_cuh = 0;

	Dwarf_Die cu_die = 0;

	int cu_number = 0, ret;

	struct probe_finder pf = {.pp = pp};
@@ -659,25 +700,27 @@ int find_probepoint(int fd, struct probe_point *pp) 
			break;



		/* Get the DIE(Debugging Information Entry) of this CU */

		ret = dwarf_siblingof(__dw_debug, 0, &cu_die, &__dw_error);

		ret = dwarf_siblingof(__dw_debug, 0, &pf.cu_die, &__dw_error);

		DIE_IF(ret != DW_DLV_OK);



		/* Check if target file is included. */

		if (pp->file)

			pf.fno = die_get_fileno(cu_die, pp->file);

			pf.fno = cu_find_fileno(pf.cu_die, pp->file);



		if (!pp->file || pf.fno) {

			/* Save CU base address (for frame_base) */

			ret = dwarf_lowpc(cu_die, &pf.cu_base, &__dw_error);

			ret = dwarf_lowpc(pf.cu_die, &pf.cu_base, &__dw_error);

			DIE_IF(ret == DW_DLV_ERROR);

			if (ret == DW_DLV_NO_ENTRY)

				pf.cu_base = 0;

			if (pp->line)

				find_by_line(cu_die, &pf);

			if (pp->function)

				find_by_func(cu_die, &pf);

				find_by_func(&pf);

			else {

				pf.lno = pp->line;

				find_by_line(&pf);

			}

		}

		dwarf_dealloc(__dw_debug, cu_die, DW_DLA_DIE);

		dwarf_dealloc(__dw_debug, pf.cu_die, DW_DLA_DIE);

	}

	ret = dwarf_finish(__dw_debug, &__dw_error);

	DIE_IF(ret != DW_DLV_OK);

tools/perf/util/probe-finder.h

+2 −0
Original line number Diff line number Diff line
@@ -41,7 +41,9 @@ struct probe_finder { 
	/* For function searching */

	Dwarf_Addr	addr;		/* Address */

	Dwarf_Unsigned	fno;		/* File number */

	Dwarf_Unsigned	lno;		/* Line number */

	Dwarf_Off	inl_offs;	/* Inline offset */

	Dwarf_Die	cu_die;		/* Current CU */



	/* For variable searching */

	Dwarf_Addr	cu_base;	/* Current CU base address */