[PATCH -tip v2 0/9]perf probe bugfixes

[PATCH -tip v2 0/9]perf probe bugfixes

[Masami Hiramatsu]

Hi,

Here is the updated version of bugfix series for perf probe.
I've added some bugfixes which come up with newer gcc.

Changes:
 - Update against recent changes on tip tree.
 - Add several actual outputs of the command for explaining
   the bugfix.
 - Add a line-walker bugfix for showing file-based probe-able
   lines correctly.
 - Rewrite variable searching scope bugfix into 2 patches.
 - Add 2 new debuginfo related bugfixes which I've found
   with newer gcc on fedora 15.

Thank you,

---

Masami Hiramatsu (9):
      [BUGFIX] perf probe: Filter out redundant inline-instances
      [BUGFIX] perf probe: Search concrete out-of-line instances
      [BUGFIX] perf probe: Avoid searching variables in intermediate scopes
      [BUGFIX] perf probe: Fix to search local variables in appropriate scope
      [BUGFIX] perf probe: Warn when more than one line are given
      [BUGFIX] perf probe: Fix to walk all inline instances
      [BUGFIX] perf probe: Fix to search nested inlined functions in CU
      [BUGFIX] perf probe: Fix line walker to check CU correctly
      [BUGFIX] perf-probe: Fix a memory leak for scopes array


 tools/perf/builtin-probe.c     |   14 ++
 tools/perf/util/dwarf-aux.c    |  210 ++++++++++++++++++++++++++++++++++--
 tools/perf/util/dwarf-aux.h    |   11 ++
 tools/perf/util/probe-finder.c |  231 +++++++++++++++++++++++++---------------
 tools/perf/util/probe-finder.h |    2 
 5 files changed, 360 insertions(+), 108 deletions(-)

-- 
Masami HIRAMATSU
Software Platform Research Dept. Linux Technology Center
Hitachi, Ltd., Yokohama Research Laboratory
E-mail: masami.hiramatsu.pt@hitachi.com

[PATCH -tip v2 1/9] [BUGFIX] perf-probe: Fix a memory leak for scopes array

[Masami Hiramatsu]

Fix a memory leak for scopes array when it finds a
variable in the global scope.

Signed-off-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Arnaldo Carvalho de Melo <acme@ghostprotocols.net>
Reviewed-by: Pekka Enberg <penberg@kernel.org>
---

 tools/perf/util/probe-finder.c |    5 ++---
 1 files changed, 2 insertions(+), 3 deletions(-)

diff --git a/tools/perf/util/probe-finder.c b/tools/perf/util/probe-finder.c
index 3e44a3e..573c723 100644
--- a/tools/perf/util/probe-finder.c
+++ b/tools/perf/util/probe-finder.c
@@ -660,6 +660,7 @@ static int find_variable(Dwarf_Die *sp_die, struct probe_finder *pf)
 	else {
 		/* Search upper class */
 		nscopes = dwarf_getscopes_die(sp_die, &scopes);
+		ret = -ENOENT;
 		while (nscopes-- > 1) {
 			pr_debug("Searching variables in %s\n",
 				 dwarf_diename(&scopes[nscopes]));
@@ -668,14 +669,12 @@ static int find_variable(Dwarf_Die *sp_die, struct probe_finder *pf)
 						 pf->pvar->var, 0,
 						 &vr_die)) {
 				ret = convert_variable(&vr_die, pf);
-				goto found;
+				break;
 			}
 		}
 		if (scopes)
 			free(scopes);
-		ret = -ENOENT;
 	}
-found:
 	if (ret < 0)
 		pr_warning("Failed to find '%s' in this function.\n",
 			   pf->pvar->var);

[PATCH -tip v2 2/9] [BUGFIX] perf probe: Fix line walker to check CU correctly

[Masami Hiramatsu]

Fix line walker to check whether a given DIE is CU or not.
Actually this function accepts CU, subprogram and
inlined_subroutine DIEs.

Without this fix, perf probe always fails to analyze lines
on inlined functions;

$ perf probe -L pre_schedule
Debuginfo analysis failed. (-2)
  Error: Failed to show lines. (-2)

This fixes that bug, as below.

$ perf probe -L pre_schedule
<pre_schedule@/home/mhiramat/ksrc/linux-2.6/kernel/sched.c:0>
      0  static inline void pre_schedule(struct rq *rq, struct task_struct *prev
         {
      2         if (prev->sched_class->pre_schedule)
      3                 prev->sched_class->pre_schedule(rq, prev);
         }

         /* rq->lock is NOT held, but preemption is disabled */


Changes from v1:
 - Update against current tip tree.(Fix dwarf-aux.c)

Signed-off-by: Masami Hiramatsu <masami.hiramatsu@gmail.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Arnaldo Carvalho de Melo <acme@ghostprotocols.net>
---

 tools/perf/util/dwarf-aux.c |    6 +++---
 1 files changed, 3 insertions(+), 3 deletions(-)

diff --git a/tools/perf/util/dwarf-aux.c b/tools/perf/util/dwarf-aux.c
index fddf40f..d35b454 100644
--- a/tools/perf/util/dwarf-aux.c
+++ b/tools/perf/util/dwarf-aux.c
@@ -439,7 +439,7 @@ static int __die_walk_culines_cb(Dwarf_Die *sp_die, void *data)
 
 /**
  * die_walk_lines - Walk on lines inside given DIE
- * @rt_die: a root DIE (CU or subprogram)
+ * @rt_die: a root DIE (CU, subprogram or inlined_subroutine)
  * @callback: callback routine
  * @data: user data
  *
@@ -460,12 +460,12 @@ int die_walk_lines(Dwarf_Die *rt_die, line_walk_callback_t callback, void *data)
 	size_t nlines, i;
 
 	/* Get the CU die */
-	if (dwarf_tag(rt_die) == DW_TAG_subprogram)
+	if (dwarf_tag(rt_die) != DW_TAG_compile_unit)
 		cu_die = dwarf_diecu(rt_die, &die_mem, NULL, NULL);
 	else
 		cu_die = rt_die;
 	if (!cu_die) {
-		pr_debug2("Failed to get CU from subprogram\n");
+		pr_debug2("Failed to get CU from given DIE.\n");
 		return -EINVAL;
 	}
 

[PATCH -tip v2 3/9] [BUGFIX] perf probe: Fix to search nested inlined functions in CU

[Masami Hiramatsu]

Fix perf probe to walk through the lines of all nested inlined
function call sites and declared lines when a whole CU is
passed to the line walker.

The die_walk_lines() can have two different type of DIEs,
subprogram(or inlined-subroutine) DIE and CU DIE.

If a caller passes a subprogram DIE, this means that the
walker walk on lines of given subprogram. In this case,
it just needs to search on direct children of DIE tree for
finding call-site information of inlined function which
directly called from given subprogram.

On the other hand, if a caller passes a CU DIE to the walker,
this means that the walker have to walk on all lines in the
source files included in given CU DIE. In this case, it has
to search whole DIE trees of all subprograms to find the
call-site information of all nested inlined functions.

Without this patch:

$ perf probe --line kernel/cpu.c:151-157
</home/mhiramat/ksrc/linux-2.6/kernel/cpu.c:151>

         static int cpu_notify(unsigned long val, void *v)
         {
    154         return __cpu_notify(val, v, -1, NULL);
         }


With this:
$ perf probe --line kernel/cpu.c:151-157
</home/mhiramat/ksrc/linux-2.6/kernel/cpu.c:151>

    152  static int cpu_notify(unsigned long val, void *v)
         {
    154         return __cpu_notify(val, v, -1, NULL);
         }

As you can see, --line option with source line range shows
the declared lines as probe-able.

Signed-off-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Arnaldo Carvalho de Melo <acme@ghostprotocols.net>
---

 tools/perf/util/dwarf-aux.c |   91 +++++++++++++++++++++++++++++++++++++------
 tools/perf/util/dwarf-aux.h |    3 +
 2 files changed, 82 insertions(+), 12 deletions(-)

diff --git a/tools/perf/util/dwarf-aux.c b/tools/perf/util/dwarf-aux.c
index d35b454..d9b8ad0 100644
--- a/tools/perf/util/dwarf-aux.c
+++ b/tools/perf/util/dwarf-aux.c
@@ -198,6 +198,19 @@ static int die_get_attr_udata(Dwarf_Die *tp_die, unsigned int attr_name,
 	return 0;
 }
 
+/* Get attribute and translate it as a sdata */
+static int die_get_attr_sdata(Dwarf_Die *tp_die, unsigned int attr_name,
+			      Dwarf_Sword *result)
+{
+	Dwarf_Attribute attr;
+
+	if (dwarf_attr(tp_die, attr_name, &attr) == NULL ||
+	    dwarf_formsdata(&attr, result) != 0)
+		return -ENOENT;
+
+	return 0;
+}
+
 /**
  * die_is_signed_type - Check whether a type DIE is signed or not
  * @tp_die: a DIE of a type
@@ -250,6 +263,39 @@ int die_get_data_member_location(Dwarf_Die *mb_die, Dwarf_Word *offs)
 	return 0;
 }
 
+/* Get the call file index number in CU DIE */
+static int die_get_call_fileno(Dwarf_Die *in_die)
+{
+	Dwarf_Sword idx;
+
+	if (die_get_attr_sdata(in_die, DW_AT_call_file, &idx) == 0)
+		return (int)idx;
+	else
+		return -ENOENT;
+}
+
+/**
+ * die_get_call_file - Get callsite file name of inlined function instance
+ * @in_die: a DIE of an inlined function instance
+ *
+ * Get call-site file name of @in_die. This means from which file the inline
+ * function is called.
+ */
+const char *die_get_call_file(Dwarf_Die *in_die)
+{
+	Dwarf_Die cu_die;
+	Dwarf_Files *files;
+	int idx;
+
+	idx = die_get_call_fileno(in_die);
+	if (idx < 0 || !dwarf_diecu(in_die, &cu_die, NULL, NULL) ||
+	    dwarf_getsrcfiles(&cu_die, &files, NULL) != 0)
+		return NULL;
+
+	return dwarf_filesrc(files, idx, NULL, NULL);
+}
+
+
 /**
  * die_find_child - Generic DIE search function in DIE tree
  * @rt_die: a root DIE
@@ -376,7 +422,7 @@ Dwarf_Die *die_find_inlinefunc(Dwarf_Die *sp_die, Dwarf_Addr addr,
 
 /* Line walker internal parameters */
 struct __line_walk_param {
-	const char *fname;
+	bool recursive;
 	line_walk_callback_t callback;
 	void *data;
 	int retval;
@@ -385,39 +431,56 @@ struct __line_walk_param {
 static int __die_walk_funclines_cb(Dwarf_Die *in_die, void *data)
 {
 	struct __line_walk_param *lw = data;
-	Dwarf_Addr addr;
+	Dwarf_Addr addr = 0;
+	const char *fname;
 	int lineno;
 
 	if (dwarf_tag(in_die) == DW_TAG_inlined_subroutine) {
+		fname = die_get_call_file(in_die);
 		lineno = die_get_call_lineno(in_die);
-		if (lineno > 0 && dwarf_entrypc(in_die, &addr) == 0) {
-			lw->retval = lw->callback(lw->fname, lineno, addr,
-						  lw->data);
+		if (fname && lineno > 0 && dwarf_entrypc(in_die, &addr) == 0) {
+			lw->retval = lw->callback(fname, lineno, addr, lw->data);
 			if (lw->retval != 0)
 				return DIE_FIND_CB_END;
 		}
 	}
-	return DIE_FIND_CB_SIBLING;
+	if (!lw->recursive)
+		/* Don't need to search recursively */
+		return DIE_FIND_CB_SIBLING;
+
+	if (addr) {
+		fname = dwarf_decl_file(in_die);
+		if (fname && dwarf_decl_line(in_die, &lineno) == 0) {
+			lw->retval = lw->callback(fname, lineno, addr, lw->data);
+			if (lw->retval != 0)
+				return DIE_FIND_CB_END;
+		}
+	}
+
+	/* Continue to search nested inlined function call-sites */
+	return DIE_FIND_CB_CONTINUE;
 }
 
 /* Walk on lines of blocks included in given DIE */
-static int __die_walk_funclines(Dwarf_Die *sp_die,
+static int __die_walk_funclines(Dwarf_Die *sp_die, bool recursive,
 				line_walk_callback_t callback, void *data)
 {
 	struct __line_walk_param lw = {
+		.recursive = recursive,
 		.callback = callback,
 		.data = data,
 		.retval = 0,
 	};
 	Dwarf_Die die_mem;
 	Dwarf_Addr addr;
+	const char *fname;
 	int lineno;
 
 	/* Handle function declaration line */
-	lw.fname = dwarf_decl_file(sp_die);
-	if (lw.fname && dwarf_decl_line(sp_die, &lineno) == 0 &&
+	fname = dwarf_decl_file(sp_die);
+	if (fname && dwarf_decl_line(sp_die, &lineno) == 0 &&
 	    dwarf_entrypc(sp_die, &addr) == 0) {
-		lw.retval = callback(lw.fname, lineno, addr, data);
+		lw.retval = callback(fname, lineno, addr, data);
 		if (lw.retval != 0)
 			goto done;
 	}
@@ -430,7 +493,7 @@ static int __die_walk_culines_cb(Dwarf_Die *sp_die, void *data)
 {
 	struct __line_walk_param *lw = data;
 
-	lw->retval = __die_walk_funclines(sp_die, lw->callback, lw->data);
+	lw->retval = __die_walk_funclines(sp_die, true, lw->callback, lw->data);
 	if (lw->retval != 0)
 		return DWARF_CB_ABORT;
 
@@ -509,7 +572,11 @@ int die_walk_lines(Dwarf_Die *rt_die, line_walk_callback_t callback, void *data)
 	 * subroutines. We have to check functions list or given function.
 	 */
 	if (rt_die != cu_die)
-		ret = __die_walk_funclines(rt_die, callback, data);
+		/*
+		 * Don't need walk functions recursively, because nested
+		 * inlined functions don't have lines of the specified DIE.
+		 */
+		ret = __die_walk_funclines(rt_die, false, callback, data);
 	else {
 		struct __line_walk_param param = {
 			.callback = callback,
diff --git a/tools/perf/util/dwarf-aux.h b/tools/perf/util/dwarf-aux.h
index bc3b211..c8e491b 100644
--- a/tools/perf/util/dwarf-aux.h
+++ b/tools/perf/util/dwarf-aux.h
@@ -40,6 +40,9 @@ extern bool die_compare_name(Dwarf_Die *dw_die, const char *tname);
 /* Get callsite line number of inline-function instance */
 extern int die_get_call_lineno(Dwarf_Die *in_die);
 
+/* Get callsite file name of inlined function instance */
+extern const char *die_get_call_file(Dwarf_Die *in_die);
+
 /* Get type die */
 extern Dwarf_Die *die_get_type(Dwarf_Die *vr_die, Dwarf_Die *die_mem);
 

[PATCH -tip v2 4/9] [BUGFIX] perf probe: Fix to walk all inline instances

[Masami Hiramatsu]

Fix line-range collector to walk all instances of inlined
function, because some execution paths can be optimized out
depends on the function argument of instances.

E.g.)
inline_func (arg) {
	if (arg)
		do_something;
	else
		do_another;
}

func_A() {
	inline_func(1)
}

func_B() {
	inline_func(0)
}

In this case, func_A may have only do_something code and
func_B may have only do_another.

Signed-off-by: Masami Hiramatsu <masami.hiramatsu@gmail.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Arnaldo Carvalho de Melo <acme@ghostprotocols.net>
---

 tools/perf/util/probe-finder.c |    8 +++++++-
 1 files changed, 7 insertions(+), 1 deletions(-)

diff --git a/tools/perf/util/probe-finder.c b/tools/perf/util/probe-finder.c
index 573c723..d6d5768 100644
--- a/tools/perf/util/probe-finder.c
+++ b/tools/perf/util/probe-finder.c
@@ -1393,7 +1393,13 @@ 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);
-	return DWARF_CB_ABORT;	/* No need to find other instances */
+
+	/*
+	 * 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;
 }
 
 /* Search function from function name */

[PATCH -tip v2 5/9] [BUGFIX] perf probe: Warn when more than one line are given

[Masami Hiramatsu]

Check multiple --lines option and print warning which
warns only the first specified --line option is valid.

Changes from the 1st post:
- Accept only the first option instead of the last.
- Fix warning message according to David's comment.
- Mark as a bugfix.


Signed-off-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Arnaldo Carvalho de Melo <acme@ghostprotocols.net>
Cc: David Ahern <dsahern@gmail.com>
---

 tools/perf/builtin-probe.c |   14 +++++++++++---
 1 files changed, 11 insertions(+), 3 deletions(-)

diff --git a/tools/perf/builtin-probe.c b/tools/perf/builtin-probe.c
index 5f2a5c7..710ae3d 100644
--- a/tools/perf/builtin-probe.c
+++ b/tools/perf/builtin-probe.c
@@ -134,10 +134,18 @@ static int opt_show_lines(const struct option *opt __used,
 {
 	int ret = 0;
 
-	if (str)
-		ret = parse_line_range_desc(str, &params.line_range);
-	INIT_LIST_HEAD(&params.line_range.line_list);
+	if (!str)
+		return 0;
+
+	if (params.show_lines) {
+		pr_warning("Warning: more than one --line options are"
+			   " detected. Only the first one is valid.\n");
+		return 0;
+	}
+
 	params.show_lines = true;
+	ret = parse_line_range_desc(str, &params.line_range);
+	INIT_LIST_HEAD(&params.line_range.line_list);
 
 	return ret;
 }

[PATCH -tip v2 6/9] [BUGFIX] perf probe: Fix to search local variables in appropriate scope

[Masami Hiramatsu]

Fix perf probe to search local variables in appropriate local
inlined function scope. For example, pre_schedule() has only
2 local variables, as below;

$ perf probe -L pre_schedule
<pre_schedule@/home/mhiramat/ksrc/linux-2.6/kernel/sched.c:0>
      0  static inline void pre_schedule(struct rq *rq, struct task_struct *prev)
         {
      2         if (prev->sched_class->pre_schedule)
      3                 prev->sched_class->pre_schedule(rq, prev);
         }

However, current perf probe shows 4 local variables on pre_schedule(),
because it searches variables in the caller(schedule()) scope.

$ perf probe -V pre_schedule
Available variables at pre_schedule
        @<schedule+445>
                int     cpu
                long unsigned int*      switch_count
                struct rq*      rq
                struct task_struct*     prev

This patch fixes this issue by searching variables in the local scope
of the instance of inlined function. Here is the result.

$ perf probe -V pre_schedule
Available variables at pre_schedule
        @<schedule+445>
                struct rq*      rq
                struct task_struct*     prev

Signed-off-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Arnaldo Carvalho de Melo <acme@ghostprotocols.net>
---

 tools/perf/util/dwarf-aux.c    |   33 ++++++++++
 tools/perf/util/dwarf-aux.h    |    4 +
 tools/perf/util/probe-finder.c |  132 ++++++++++++++++++++++++++++++++--------
 tools/perf/util/probe-finder.h |    2 -
 4 files changed, 144 insertions(+), 27 deletions(-)

diff --git a/tools/perf/util/dwarf-aux.c b/tools/perf/util/dwarf-aux.c
index d9b8ad0..425703a 100644
--- a/tools/perf/util/dwarf-aux.c
+++ b/tools/perf/util/dwarf-aux.c
@@ -96,6 +96,39 @@ int cu_find_lineinfo(Dwarf_Die *cu_die, unsigned long addr,
 	return *lineno ?: -ENOENT;
 }
 
+static int __die_find_inline_cb(Dwarf_Die *die_mem, void *data);
+
+/**
+ * cu_walk_functions_at - Walk on function DIEs at given address
+ * @cu_die: A CU DIE
+ * @addr: An address
+ * @callback: A callback which called with found DIEs
+ * @data: A user data
+ *
+ * Walk on function DIEs at given @addr in @cu_die. Passed DIEs
+ * should be subprogram or inlined-subroutines.
+ */
+int cu_walk_functions_at(Dwarf_Die *cu_die, Dwarf_Addr addr,
+		    int (*callback)(Dwarf_Die *, void *), void *data)
+{
+	Dwarf_Die die_mem;
+	Dwarf_Die *sc_die;
+	int ret = -ENOENT;
+
+	/* Inlined function could be recursive. Trace it until fail */
+	for (sc_die = die_find_realfunc(cu_die, addr, &die_mem);
+	     sc_die != NULL;
+	     sc_die = die_find_child(sc_die, __die_find_inline_cb, &addr,
+				     &die_mem)) {
+		ret = callback(sc_die, data);
+		if (ret)
+			break;
+	}
+
+	return ret;
+
+}
+
 /**
  * die_compare_name - Compare diename and tname
  * @dw_die: a DIE
diff --git a/tools/perf/util/dwarf-aux.h b/tools/perf/util/dwarf-aux.h
index c8e491b..6f46106 100644
--- a/tools/perf/util/dwarf-aux.h
+++ b/tools/perf/util/dwarf-aux.h
@@ -34,6 +34,10 @@ extern const char *cu_get_comp_dir(Dwarf_Die *cu_die);
 extern int cu_find_lineinfo(Dwarf_Die *cudie, unsigned long addr,
 			    const char **fname, int *lineno);
 
+/* Walk on funcitons at given address */
+extern int cu_walk_functions_at(Dwarf_Die *cu_die, Dwarf_Addr addr,
+			int (*callback)(Dwarf_Die *, void *), void *data);
+
 /* Compare diename and tname */
 extern bool die_compare_name(Dwarf_Die *dw_die, const char *tname);
 
diff --git a/tools/perf/util/probe-finder.c b/tools/perf/util/probe-finder.c
index d6d5768..5c83b7d 100644
--- a/tools/perf/util/probe-finder.c
+++ b/tools/perf/util/probe-finder.c
@@ -612,8 +612,8 @@ static int convert_variable(Dwarf_Die *vr_die, struct probe_finder *pf)
 	return ret;
 }
 
-/* Find a variable in a subprogram die */
-static int find_variable(Dwarf_Die *sp_die, struct probe_finder *pf)
+/* Find a variable in a scope DIE */
+static int find_variable(Dwarf_Die *sc_die, struct probe_finder *pf)
 {
 	Dwarf_Die vr_die, *scopes;
 	char buf[32], *ptr;
@@ -655,11 +655,11 @@ static int find_variable(Dwarf_Die *sp_die, struct probe_finder *pf)
 	pr_debug("Searching '%s' variable in context.\n",
 		 pf->pvar->var);
 	/* Search child die for local variables and parameters. */
-	if (die_find_variable_at(sp_die, pf->pvar->var, pf->addr, &vr_die))
+	if (die_find_variable_at(sc_die, pf->pvar->var, pf->addr, &vr_die))
 		ret = convert_variable(&vr_die, pf);
 	else {
 		/* Search upper class */
-		nscopes = dwarf_getscopes_die(sp_die, &scopes);
+		nscopes = dwarf_getscopes_die(sc_die, &scopes);
 		ret = -ENOENT;
 		while (nscopes-- > 1) {
 			pr_debug("Searching variables in %s\n",
@@ -717,26 +717,30 @@ static int convert_to_trace_point(Dwarf_Die *sp_die, Dwarf_Addr paddr,
 	return 0;
 }
 
-/* Call probe_finder callback with real subprogram DIE */
-static int call_probe_finder(Dwarf_Die *sp_die, struct probe_finder *pf)
+/* Call probe_finder callback with scope DIE */
+static int call_probe_finder(Dwarf_Die *sc_die, struct probe_finder *pf)
 {
-	Dwarf_Die die_mem;
 	Dwarf_Attribute fb_attr;
 	size_t nops;
 	int ret;
 
-	/* If no real subprogram, find a real one */
-	if (!sp_die || dwarf_tag(sp_die) != DW_TAG_subprogram) {
-		sp_die = die_find_realfunc(&pf->cu_die, pf->addr, &die_mem);
-		if (!sp_die) {
+	if (!sc_die) {
+		pr_err("Caller must pass a scope DIE. Program error.\n");
+		return -EINVAL;
+	}
+
+	/* If not a real subprogram, find a real one */
+	if (dwarf_tag(sc_die) != DW_TAG_subprogram) {
+		if (!die_find_realfunc(&pf->cu_die, pf->addr, &pf->sp_die)) {
 			pr_warning("Failed to find probe point in any "
 				   "functions.\n");
 			return -ENOENT;
 		}
-	}
+	} else
+		memcpy(&pf->sp_die, sc_die, sizeof(Dwarf_Die));
 
-	/* Get the frame base attribute/ops */
-	dwarf_attr(sp_die, DW_AT_frame_base, &fb_attr);
+	/* Get the frame base attribute/ops from subprogram */
+	dwarf_attr(&pf->sp_die, DW_AT_frame_base, &fb_attr);
 	ret = dwarf_getlocation_addr(&fb_attr, pf->addr, &pf->fb_ops, &nops, 1);
 	if (ret <= 0 || nops == 0) {
 		pf->fb_ops = NULL;
@@ -754,7 +758,7 @@ static int call_probe_finder(Dwarf_Die *sp_die, struct probe_finder *pf)
 	}
 
 	/* Call finder's callback handler */
-	ret = pf->callback(sp_die, pf);
+	ret = pf->callback(sc_die, pf);
 
 	/* *pf->fb_ops will be cached in libdw. Don't free it. */
 	pf->fb_ops = NULL;
@@ -762,17 +766,82 @@ static int call_probe_finder(Dwarf_Die *sp_die, struct probe_finder *pf)
 	return ret;
 }
 
+struct find_scope_param {
+	const char *function;
+	const char *file;
+	int line;
+	int diff;
+	Dwarf_Die *die_mem;
+	bool found;
+};
+
+static int find_best_scope_cb(Dwarf_Die *fn_die, void *data)
+{
+	struct find_scope_param *fsp = data;
+	const char *file;
+	int lno;
+
+	/* Skip if declared file name does not match */
+	if (fsp->file) {
+		file = dwarf_decl_file(fn_die);
+		if (!file || strcmp(fsp->file, file) != 0)
+			return 0;
+	}
+	/* If the function name is given, that's what user expects */
+	if (fsp->function) {
+		if (die_compare_name(fn_die, fsp->function)) {
+			memcpy(fsp->die_mem, fn_die, sizeof(Dwarf_Die));
+			fsp->found = true;
+			return 1;
+		}
+	} else {
+		/* With the line number, find the nearest declared DIE */
+		dwarf_decl_line(fn_die, &lno);
+		if (lno < fsp->line && fsp->diff > fsp->line - lno) {
+			/* Keep a candidate and continue */
+			fsp->diff = fsp->line - lno;
+			memcpy(fsp->die_mem, fn_die, sizeof(Dwarf_Die));
+			fsp->found = true;
+		}
+	}
+	return 0;
+}
+
+/* Find an appropriate scope fits to given conditions */
+static Dwarf_Die *find_best_scope(struct probe_finder *pf, Dwarf_Die *die_mem)
+{
+	struct find_scope_param fsp = {
+		.function = pf->pev->point.function,
+		.file = pf->fname,
+		.line = pf->lno,
+		.diff = INT_MAX,
+		.die_mem = die_mem,
+		.found = false,
+	};
+
+	cu_walk_functions_at(&pf->cu_die, pf->addr, find_best_scope_cb, &fsp);
+
+	return fsp.found ? die_mem : NULL;
+}
+
 static int probe_point_line_walker(const char *fname, int lineno,
 				   Dwarf_Addr addr, void *data)
 {
 	struct probe_finder *pf = data;
+	Dwarf_Die *sc_die, die_mem;
 	int ret;
 
 	if (lineno != pf->lno || strtailcmp(fname, pf->fname) != 0)
 		return 0;
 
 	pf->addr = addr;
-	ret = call_probe_finder(NULL, pf);
+	sc_die = find_best_scope(pf, &die_mem);
+	if (!sc_die) {
+		pr_warning("Failed to find scope of probe point.\n");
+		return -ENOENT;
+	}
+
+	ret = call_probe_finder(sc_die, pf);
 
 	/* Continue if no error, because the line will be in inline function */
 	return ret < 0 ? ret : 0;
@@ -826,6 +895,7 @@ static int probe_point_lazy_walker(const char *fname, int lineno,
 				   Dwarf_Addr addr, void *data)
 {
 	struct probe_finder *pf = data;
+	Dwarf_Die *sc_die, die_mem;
 	int ret;
 
 	if (!line_list__has_line(&pf->lcache, lineno) ||
@@ -835,7 +905,14 @@ static int probe_point_lazy_walker(const char *fname, int lineno,
 	pr_debug("Probe line found: line:%d addr:0x%llx\n",
 		 lineno, (unsigned long long)addr);
 	pf->addr = addr;
-	ret = call_probe_finder(NULL, pf);
+	pf->lno = lineno;
+	sc_die = find_best_scope(pf, &die_mem);
+	if (!sc_die) {
+		pr_warning("Failed to find scope of probe point.\n");
+		return -ENOENT;
+	}
+
+	ret = call_probe_finder(sc_die, pf);
 
 	/*
 	 * Continue if no error, because the lazy pattern will match
@@ -1059,7 +1136,7 @@ found:
 }
 
 /* Add a found probe point into trace event list */
-static int add_probe_trace_event(Dwarf_Die *sp_die, struct probe_finder *pf)
+static int add_probe_trace_event(Dwarf_Die *sc_die, struct probe_finder *pf)
 {
 	struct trace_event_finder *tf =
 			container_of(pf, struct trace_event_finder, pf);
@@ -1074,8 +1151,9 @@ static int add_probe_trace_event(Dwarf_Die *sp_die, struct probe_finder *pf)
 	}
 	tev = &tf->tevs[tf->ntevs++];
 
-	ret = convert_to_trace_point(sp_die, pf->addr, pf->pev->point.retprobe,
-				     &tev->point);
+	/* Trace point should be converted from subprogram DIE */
+	ret = convert_to_trace_point(&pf->sp_die, pf->addr,
+				     pf->pev->point.retprobe, &tev->point);
 	if (ret < 0)
 		return ret;
 
@@ -1090,7 +1168,8 @@ static int add_probe_trace_event(Dwarf_Die *sp_die, struct probe_finder *pf)
 	for (i = 0; i < pf->pev->nargs; i++) {
 		pf->pvar = &pf->pev->args[i];
 		pf->tvar = &tev->args[i];
-		ret = find_variable(sp_die, pf);
+		/* Variable should be found from scope DIE */
+		ret = find_variable(sc_die, pf);
 		if (ret != 0)
 			return ret;
 	}
@@ -1158,7 +1237,7 @@ static int collect_variables_cb(Dwarf_Die *die_mem, void *data)
 }
 
 /* Add a found vars into available variables list */
-static int add_available_vars(Dwarf_Die *sp_die, struct probe_finder *pf)
+static int add_available_vars(Dwarf_Die *sc_die, struct probe_finder *pf)
 {
 	struct available_var_finder *af =
 			container_of(pf, struct available_var_finder, pf);
@@ -1173,8 +1252,9 @@ static int add_available_vars(Dwarf_Die *sp_die, struct probe_finder *pf)
 	}
 	vl = &af->vls[af->nvls++];
 
-	ret = convert_to_trace_point(sp_die, pf->addr, pf->pev->point.retprobe,
-				     &vl->point);
+	/* Trace point should be converted from subprogram DIE */
+	ret = convert_to_trace_point(&pf->sp_die, pf->addr,
+				     pf->pev->point.retprobe, &vl->point);
 	if (ret < 0)
 		return ret;
 
@@ -1186,14 +1266,14 @@ static int add_available_vars(Dwarf_Die *sp_die, struct probe_finder *pf)
 	if (vl->vars == NULL)
 		return -ENOMEM;
 	af->child = true;
-	die_find_child(sp_die, collect_variables_cb, (void *)af, &die_mem);
+	die_find_child(sc_die, collect_variables_cb, (void *)af, &die_mem);
 
 	/* Find external variables */
 	if (!af->externs)
 		goto out;
 	/* Don't need to search child DIE for externs. */
 	af->child = false;
-	nscopes = dwarf_getscopes_die(sp_die, &scopes);
+	nscopes = dwarf_getscopes_die(sc_die, &scopes);
 	while (nscopes-- > 1)
 		die_find_child(&scopes[nscopes], collect_variables_cb,
 			       (void *)af, &die_mem);
diff --git a/tools/perf/util/probe-finder.h b/tools/perf/util/probe-finder.h
index c478b42..1132c8f 100644
--- a/tools/perf/util/probe-finder.h
+++ b/tools/perf/util/probe-finder.h
@@ -57,7 +57,7 @@ struct probe_finder {
 	struct perf_probe_event	*pev;		/* Target probe event */
 
 	/* Callback when a probe point is found */
-	int (*callback)(Dwarf_Die *sp_die, struct probe_finder *pf);
+	int (*callback)(Dwarf_Die *sc_die, struct probe_finder *pf);
 
 	/* For function searching */
 	int			lno;		/* Line number */

[PATCH -tip v2 7/9] [BUGFIX] perf probe: Avoid searching variables in intermediate scopes

[Masami Hiramatsu]

Fix variable searching logic to search one in inner than local
scope or global(CU) scope. In the other words, skip searching
in intermediate scopes.

e.g., in the following code,

int var1;

void inline infunc(int i)
{
    i++;   <--- [A]
}

void func(void)
{
   int var1, var2;
   infunc(var2);
}

At the [A], "var1" should point the global variable "var1",
however, if user mis-typed as "var2", variable search should
be failed. However, current logic searches variable infunc()
scope, global scope, and then func() scope. Thus, it can
find "var2" variable in func() scope. This may not be what
user expects.

So, it would better not search outer scopes except outermost
(compile unit) scope which contains only global variables,
when it failed to find given variable in local scope.

E.g.

Without this:
$ perf probe -V pre_schedule --externs > without.vars

With this:
$ perf probe -V pre_schedule --externs > with.vars

Check the diff:
$ diff without.vars with.vars
88d87
<               int     cpu
133d131
<               long unsigned int*      switch_count

These vars are actually in the scope of schedule(),
the caller of pre_schedule().


Signed-off-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Arnaldo Carvalho de Melo <acme@ghostprotocols.net>
---

 tools/perf/util/probe-finder.c |   44 ++++++++++++----------------------------
 1 files changed, 13 insertions(+), 31 deletions(-)

diff --git a/tools/perf/util/probe-finder.c b/tools/perf/util/probe-finder.c
index 5c83b7d..114542a 100644
--- a/tools/perf/util/probe-finder.c
+++ b/tools/perf/util/probe-finder.c
@@ -615,9 +615,9 @@ static int convert_variable(Dwarf_Die *vr_die, struct probe_finder *pf)
 /* Find a variable in a scope DIE */
 static int find_variable(Dwarf_Die *sc_die, struct probe_finder *pf)
 {
-	Dwarf_Die vr_die, *scopes;
+	Dwarf_Die vr_die;
 	char buf[32], *ptr;
-	int ret, nscopes;
+	int ret = 0;
 
 	if (!is_c_varname(pf->pvar->var)) {
 		/* Copy raw parameters */
@@ -652,29 +652,16 @@ static int find_variable(Dwarf_Die *sc_die, struct probe_finder *pf)
 	if (pf->tvar->name == NULL)
 		return -ENOMEM;
 
-	pr_debug("Searching '%s' variable in context.\n",
-		 pf->pvar->var);
+	pr_debug("Searching '%s' variable in context.\n", pf->pvar->var);
 	/* Search child die for local variables and parameters. */
-	if (die_find_variable_at(sc_die, pf->pvar->var, pf->addr, &vr_die))
-		ret = convert_variable(&vr_die, pf);
-	else {
-		/* Search upper class */
-		nscopes = dwarf_getscopes_die(sc_die, &scopes);
-		ret = -ENOENT;
-		while (nscopes-- > 1) {
-			pr_debug("Searching variables in %s\n",
-				 dwarf_diename(&scopes[nscopes]));
-			/* We should check this scope, so give dummy address */
-			if (die_find_variable_at(&scopes[nscopes],
-						 pf->pvar->var, 0,
-						 &vr_die)) {
-				ret = convert_variable(&vr_die, pf);
-				break;
-			}
-		}
-		if (scopes)
-			free(scopes);
+	if (!die_find_variable_at(sc_die, pf->pvar->var, pf->addr, &vr_die)) {
+		/* Search again in global variables */
+		if (!die_find_variable_at(&pf->cu_die, pf->pvar->var, 0, &vr_die))
+			ret = -ENOENT;
 	}
+	if (ret == 0)
+		ret = convert_variable(&vr_die, pf);
+
 	if (ret < 0)
 		pr_warning("Failed to find '%s' in this function.\n",
 			   pf->pvar->var);
@@ -1242,8 +1229,8 @@ static int add_available_vars(Dwarf_Die *sc_die, struct probe_finder *pf)
 	struct available_var_finder *af =
 			container_of(pf, struct available_var_finder, pf);
 	struct variable_list *vl;
-	Dwarf_Die die_mem, *scopes = NULL;
-	int ret, nscopes;
+	Dwarf_Die die_mem;
+	int ret;
 
 	/* Check number of tevs */
 	if (af->nvls == af->max_vls) {
@@ -1273,12 +1260,7 @@ static int add_available_vars(Dwarf_Die *sc_die, struct probe_finder *pf)
 		goto out;
 	/* Don't need to search child DIE for externs. */
 	af->child = false;
-	nscopes = dwarf_getscopes_die(sc_die, &scopes);
-	while (nscopes-- > 1)
-		die_find_child(&scopes[nscopes], collect_variables_cb,
-			       (void *)af, &die_mem);
-	if (scopes)
-		free(scopes);
+	die_find_child(&pf->cu_die, collect_variables_cb, (void *)af, &die_mem);
 
 out:
 	if (strlist__empty(vl->vars)) {

[PATCH -tip v2 8/9] [BUGFIX] perf probe: Search concrete out-of-line instances

[Masami Hiramatsu]

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,
# perf probe -V sched_group_rt_period
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,

# perf probe -V sched_group_rt_period
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.

Signed-off-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Arnaldo Carvalho de Melo <acme@ghostprotocols.net>
---

 tools/perf/util/dwarf-aux.c    |   58 ++++++++++++++++++++++++++++++++++++++++
 tools/perf/util/dwarf-aux.h    |    4 +++
 tools/perf/util/probe-finder.c |   56 ++++++++++++++-------------------------
 3 files changed, 83 insertions(+), 35 deletions(-)

diff --git a/tools/perf/util/dwarf-aux.c b/tools/perf/util/dwarf-aux.c
index 425703a..d0f4048 100644
--- a/tools/perf/util/dwarf-aux.c
+++ b/tools/perf/util/dwarf-aux.c
@@ -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;
diff --git a/tools/perf/util/dwarf-aux.h b/tools/perf/util/dwarf-aux.h
index 6f46106..6ce1717 100644
--- a/tools/perf/util/dwarf-aux.h
+++ b/tools/perf/util/dwarf-aux.h
@@ -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);
diff --git a/tools/perf/util/probe-finder.c b/tools/perf/util/probe-finder.c
index 114542a..555fc38 100644
--- a/tools/perf/util/probe-finder.c
+++ b/tools/perf/util/probe-finder.c
@@ -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;
 	}

[PATCH -tip v2 9/9] [BUGFIX] perf probe: Filter out redundant inline-instances

[Masami Hiramatsu]

With gcc4.6, some instances of concrete inlined function
looks redundant and broken, because it appears inside of a
concrete instance and its call_file and call_line are same
as the original abstruct's decl_file and decl_line respectively.

e.g.
 [  d1aa]    subprogram
             external             (flag) Yes
             name                 (strp) "add_timer"
             decl_file            (data1) 2		;here is original
             decl_line            (data2) 847		;line and file
             prototyped           (flag) Yes
             inline               (data1) inlined (1)
             sibling              (ref4) [  d1c6]
...
 [ 11d84]    subprogram
             abstract_origin      (ref4) [  d1aa]	; concrete instance
             low_pc               (addr) .text+0x000000000000246f <add_timer>
             high_pc              (addr) .text+0x000000000000248b <mod_timer_pending>
             frame_base           (block1)               [   0] call_frame_cfa
             sibling              (ref4) [ 11dd9]
 [ 11d9f]      formal_parameter
               abstract_origin      (ref4) [  d1b9]
               location             (data4) location list [  701b]
 [ 11da8]      inlined_subroutine
               abstract_origin      (ref4) [  d1aa]	; redundant instance
               low_pc               (addr) .text+0x000000000000247e <add_timer+0xf>
               high_pc              (addr) .text+0x0000000000002480 <add_timer+0x11>
               call_file            (data1) 2		; call line and file
               call_line            (data2) 847		; are same as above


Those redundant instances leads unwilling results;

e.g. find probe points inside of functions even if we specify
a function entry as below;

$ perf probe -V add_timer
Available variables at add_timer
        @<add_timer+0>
                struct timer_list*      timer
        @<add_timer+15>
                (No matched variables)

So, this filters out those redundant instances based on
call-site and decl-site information.

Signed-off-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Arnaldo Carvalho de Melo <acme@ghostprotocols.net>
---

 tools/perf/util/dwarf-aux.c |   22 ++++++++++++++++++++++
 1 files changed, 22 insertions(+), 0 deletions(-)

diff --git a/tools/perf/util/dwarf-aux.c b/tools/perf/util/dwarf-aux.c
index d0f4048..ee51e9b 100644
--- a/tools/perf/util/dwarf-aux.c
+++ b/tools/perf/util/dwarf-aux.c
@@ -307,6 +307,17 @@ static int die_get_call_fileno(Dwarf_Die *in_die)
 		return -ENOENT;
 }
 
+/* Get the declared file index number in CU DIE */
+static int die_get_decl_fileno(Dwarf_Die *pdie)
+{
+	Dwarf_Sword idx;
+
+	if (die_get_attr_sdata(pdie, DW_AT_decl_file, &idx) == 0)
+		return (int)idx;
+	else
+		return -ENOENT;
+}
+
 /**
  * die_get_call_file - Get callsite file name of inlined function instance
  * @in_die: a DIE of an inlined function instance
@@ -467,6 +478,7 @@ static int __die_walk_instances_cb(Dwarf_Die *inst, void *data)
 	Dwarf_Die origin_mem;
 	Dwarf_Attribute *attr;
 	Dwarf_Die *origin;
+	int tmp;
 
 	attr = dwarf_attr(inst, DW_AT_abstract_origin, &attr_mem);
 	if (attr == NULL)
@@ -476,6 +488,16 @@ static int __die_walk_instances_cb(Dwarf_Die *inst, void *data)
 	if (origin == NULL || origin->addr != iwp->addr)
 		return DIE_FIND_CB_CONTINUE;
 
+	/* Ignore redundant instances */
+	if (dwarf_tag(inst) == DW_TAG_inlined_subroutine) {
+		dwarf_decl_line(origin, &tmp);
+		if (die_get_call_lineno(inst) == tmp) {
+			tmp = die_get_decl_fileno(origin);
+			if (die_get_call_fileno(inst) == tmp)
+				return DIE_FIND_CB_CONTINUE;
+		}
+	}
+
 	iwp->retval = iwp->callback(inst, iwp->data);
 
 	return (iwp->retval) ? DIE_FIND_CB_END : DIE_FIND_CB_CONTINUE;

[tip:perf/core] perf probe: Fix a memory leak for scopes array

[tip-bot for Masami Hiramatsu]

Commit-ID:  8afa2a707d3d1320df5d35966729ac5262da737d
Gitweb:     http://git.kernel.org/tip/8afa2a707d3d1320df5d35966729ac5262da737d
Author:     Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
AuthorDate: Thu, 11 Aug 2011 20:02:29 +0900
Committer:  Arnaldo Carvalho de Melo <acme@redhat.com>
CommitDate: Fri, 12 Aug 2011 09:21:15 -0300

perf probe: Fix a memory leak for scopes array

Fix a memory leak for scopes array when it finds a variable in the
global scope.

Reviewed-by: Pekka Enberg <penberg@kernel.org>
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/20110811110229.19900.63019.stgit@fedora15
Signed-off-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
---
 tools/perf/util/probe-finder.c |    5 ++---
 1 files changed, 2 insertions(+), 3 deletions(-)

diff --git a/tools/perf/util/probe-finder.c b/tools/perf/util/probe-finder.c
index 3e44a3e..573c723 100644
--- a/tools/perf/util/probe-finder.c
+++ b/tools/perf/util/probe-finder.c
@@ -660,6 +660,7 @@ static int find_variable(Dwarf_Die *sp_die, struct probe_finder *pf)
 	else {
 		/* Search upper class */
 		nscopes = dwarf_getscopes_die(sp_die, &scopes);
+		ret = -ENOENT;
 		while (nscopes-- > 1) {
 			pr_debug("Searching variables in %s\n",
 				 dwarf_diename(&scopes[nscopes]));
@@ -668,14 +669,12 @@ static int find_variable(Dwarf_Die *sp_die, struct probe_finder *pf)
 						 pf->pvar->var, 0,
 						 &vr_die)) {
 				ret = convert_variable(&vr_die, pf);
-				goto found;
+				break;
 			}
 		}
 		if (scopes)
 			free(scopes);
-		ret = -ENOENT;
 	}
-found:
 	if (ret < 0)
 		pr_warning("Failed to find '%s' in this function.\n",
 			   pf->pvar->var);

[tip:perf/core] perf probe: Fix line walker to check CU correctly

[tip-bot for Masami Hiramatsu]

Commit-ID:  a128405c6b40371c59c34b00cc66ed06285b9551
Gitweb:     http://git.kernel.org/tip/a128405c6b40371c59c34b00cc66ed06285b9551
Author:     Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
AuthorDate: Thu, 11 Aug 2011 20:02:35 +0900
Committer:  Arnaldo Carvalho de Melo <acme@redhat.com>
CommitDate: Fri, 12 Aug 2011 09:22:46 -0300

perf probe: Fix line walker to check CU correctly

Fix line walker to check whether a given DIE is CU or not.

Actually this function accepts CU, subprogram and inlined_subroutine
DIEs.

Without this fix, perf probe always fails to analyze lines on inlined
functions;

$ perf probe -L pre_schedule
Debuginfo analysis failed. (-2)
  Error: Failed to show lines. (-2)

This fixes that bug, as below.

$ perf probe -L pre_schedule
<pre_schedule@/home/mhiramat/ksrc/linux-2.6/kernel/sched.c:0>
      0  static inline void pre_schedule(struct rq *rq, struct task_struct *prev
         {
      2         if (prev->sched_class->pre_schedule)
      3                 prev->sched_class->pre_schedule(rq, prev);
         }

         /* rq->lock is NOT held, but preemption is disabled */

Changes from v1:
 - Update against current tip tree.(Fix dwarf-aux.c)

Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Masami Hiramatsu <masami.hiramatsu@gmail.com>
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/20110811110235.19900.20614.stgit@fedora15
Signed-off-by: Masami Hiramatsu <masami.hiramatsu@gmail.com>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
---
 tools/perf/util/dwarf-aux.c |    6 +++---
 1 files changed, 3 insertions(+), 3 deletions(-)

diff --git a/tools/perf/util/dwarf-aux.c b/tools/perf/util/dwarf-aux.c
index fddf40f..d35b454 100644
--- a/tools/perf/util/dwarf-aux.c
+++ b/tools/perf/util/dwarf-aux.c
@@ -439,7 +439,7 @@ static int __die_walk_culines_cb(Dwarf_Die *sp_die, void *data)
 
 /**
  * die_walk_lines - Walk on lines inside given DIE
- * @rt_die: a root DIE (CU or subprogram)
+ * @rt_die: a root DIE (CU, subprogram or inlined_subroutine)
  * @callback: callback routine
  * @data: user data
  *
@@ -460,12 +460,12 @@ int die_walk_lines(Dwarf_Die *rt_die, line_walk_callback_t callback, void *data)
 	size_t nlines, i;
 
 	/* Get the CU die */
-	if (dwarf_tag(rt_die) == DW_TAG_subprogram)
+	if (dwarf_tag(rt_die) != DW_TAG_compile_unit)
 		cu_die = dwarf_diecu(rt_die, &die_mem, NULL, NULL);
 	else
 		cu_die = rt_die;
 	if (!cu_die) {
-		pr_debug2("Failed to get CU from subprogram\n");
+		pr_debug2("Failed to get CU from given DIE.\n");
 		return -EINVAL;
 	}
 

[tip:perf/core] perf probe: Fix to search nested inlined functions in CU

[tip-bot for Masami Hiramatsu]

Commit-ID:  b0e9cb2802d4bf50955cca8a7d87cf94ebf750a5
Gitweb:     http://git.kernel.org/tip/b0e9cb2802d4bf50955cca8a7d87cf94ebf750a5
Author:     Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
AuthorDate: Thu, 11 Aug 2011 20:02:41 +0900
Committer:  Arnaldo Carvalho de Melo <acme@redhat.com>
CommitDate: Fri, 12 Aug 2011 09:23:39 -0300

perf probe: Fix to search nested inlined functions in CU

Fix perf probe to walk through the lines of all nested inlined function
call sites and declared lines when a whole CU is passed to the line
walker.

The die_walk_lines() can have two different type of DIEs, subprogram (or
inlined-subroutine) DIE and CU DIE.

If a caller passes a subprogram DIE, this means that the walker walk on
lines of given subprogram. In this case, it just needs to search on
direct children of DIE tree for finding call-site information of inlined
function which directly called from given subprogram.

On the other hand, if a caller passes a CU DIE to the walker, this means
that the walker have to walk on all lines in the source files included
in given CU DIE. In this case, it has to search whole DIE trees of all
subprograms to find the call-site information of all nested inlined
functions.

Without this patch:

$ perf probe --line kernel/cpu.c:151-157
</home/mhiramat/ksrc/linux-2.6/kernel/cpu.c:151>

         static int cpu_notify(unsigned long val, void *v)
         {
    154         return __cpu_notify(val, v, -1, NULL);
         }

With this:
$ perf probe --line kernel/cpu.c:151-157
</home/mhiramat/ksrc/linux-2.6/kernel/cpu.c:151>

    152  static int cpu_notify(unsigned long val, void *v)
         {
    154         return __cpu_notify(val, v, -1, NULL);
         }

As you can see, --line option with source line range shows the declared
lines as probe-able.

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/20110811110241.19900.34994.stgit@fedora15
Signed-off-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
---
 tools/perf/util/dwarf-aux.c |   91 +++++++++++++++++++++++++++++++++++++------
 tools/perf/util/dwarf-aux.h |    3 +
 2 files changed, 82 insertions(+), 12 deletions(-)

diff --git a/tools/perf/util/dwarf-aux.c b/tools/perf/util/dwarf-aux.c
index d35b454..d9b8ad0 100644
--- a/tools/perf/util/dwarf-aux.c
+++ b/tools/perf/util/dwarf-aux.c
@@ -198,6 +198,19 @@ static int die_get_attr_udata(Dwarf_Die *tp_die, unsigned int attr_name,
 	return 0;
 }
 
+/* Get attribute and translate it as a sdata */
+static int die_get_attr_sdata(Dwarf_Die *tp_die, unsigned int attr_name,
+			      Dwarf_Sword *result)
+{
+	Dwarf_Attribute attr;
+
+	if (dwarf_attr(tp_die, attr_name, &attr) == NULL ||
+	    dwarf_formsdata(&attr, result) != 0)
+		return -ENOENT;
+
+	return 0;
+}
+
 /**
  * die_is_signed_type - Check whether a type DIE is signed or not
  * @tp_die: a DIE of a type
@@ -250,6 +263,39 @@ int die_get_data_member_location(Dwarf_Die *mb_die, Dwarf_Word *offs)
 	return 0;
 }
 
+/* Get the call file index number in CU DIE */
+static int die_get_call_fileno(Dwarf_Die *in_die)
+{
+	Dwarf_Sword idx;
+
+	if (die_get_attr_sdata(in_die, DW_AT_call_file, &idx) == 0)
+		return (int)idx;
+	else
+		return -ENOENT;
+}
+
+/**
+ * die_get_call_file - Get callsite file name of inlined function instance
+ * @in_die: a DIE of an inlined function instance
+ *
+ * Get call-site file name of @in_die. This means from which file the inline
+ * function is called.
+ */
+const char *die_get_call_file(Dwarf_Die *in_die)
+{
+	Dwarf_Die cu_die;
+	Dwarf_Files *files;
+	int idx;
+
+	idx = die_get_call_fileno(in_die);
+	if (idx < 0 || !dwarf_diecu(in_die, &cu_die, NULL, NULL) ||
+	    dwarf_getsrcfiles(&cu_die, &files, NULL) != 0)
+		return NULL;
+
+	return dwarf_filesrc(files, idx, NULL, NULL);
+}
+
+
 /**
  * die_find_child - Generic DIE search function in DIE tree
  * @rt_die: a root DIE
@@ -376,7 +422,7 @@ Dwarf_Die *die_find_inlinefunc(Dwarf_Die *sp_die, Dwarf_Addr addr,
 
 /* Line walker internal parameters */
 struct __line_walk_param {
-	const char *fname;
+	bool recursive;
 	line_walk_callback_t callback;
 	void *data;
 	int retval;
@@ -385,39 +431,56 @@ struct __line_walk_param {
 static int __die_walk_funclines_cb(Dwarf_Die *in_die, void *data)
 {
 	struct __line_walk_param *lw = data;
-	Dwarf_Addr addr;
+	Dwarf_Addr addr = 0;
+	const char *fname;
 	int lineno;
 
 	if (dwarf_tag(in_die) == DW_TAG_inlined_subroutine) {
+		fname = die_get_call_file(in_die);
 		lineno = die_get_call_lineno(in_die);
-		if (lineno > 0 && dwarf_entrypc(in_die, &addr) == 0) {
-			lw->retval = lw->callback(lw->fname, lineno, addr,
-						  lw->data);
+		if (fname && lineno > 0 && dwarf_entrypc(in_die, &addr) == 0) {
+			lw->retval = lw->callback(fname, lineno, addr, lw->data);
 			if (lw->retval != 0)
 				return DIE_FIND_CB_END;
 		}
 	}
-	return DIE_FIND_CB_SIBLING;
+	if (!lw->recursive)
+		/* Don't need to search recursively */
+		return DIE_FIND_CB_SIBLING;
+
+	if (addr) {
+		fname = dwarf_decl_file(in_die);
+		if (fname && dwarf_decl_line(in_die, &lineno) == 0) {
+			lw->retval = lw->callback(fname, lineno, addr, lw->data);
+			if (lw->retval != 0)
+				return DIE_FIND_CB_END;
+		}
+	}
+
+	/* Continue to search nested inlined function call-sites */
+	return DIE_FIND_CB_CONTINUE;
 }
 
 /* Walk on lines of blocks included in given DIE */
-static int __die_walk_funclines(Dwarf_Die *sp_die,
+static int __die_walk_funclines(Dwarf_Die *sp_die, bool recursive,
 				line_walk_callback_t callback, void *data)
 {
 	struct __line_walk_param lw = {
+		.recursive = recursive,
 		.callback = callback,
 		.data = data,
 		.retval = 0,
 	};
 	Dwarf_Die die_mem;
 	Dwarf_Addr addr;
+	const char *fname;
 	int lineno;
 
 	/* Handle function declaration line */
-	lw.fname = dwarf_decl_file(sp_die);
-	if (lw.fname && dwarf_decl_line(sp_die, &lineno) == 0 &&
+	fname = dwarf_decl_file(sp_die);
+	if (fname && dwarf_decl_line(sp_die, &lineno) == 0 &&
 	    dwarf_entrypc(sp_die, &addr) == 0) {
-		lw.retval = callback(lw.fname, lineno, addr, data);
+		lw.retval = callback(fname, lineno, addr, data);
 		if (lw.retval != 0)
 			goto done;
 	}
@@ -430,7 +493,7 @@ static int __die_walk_culines_cb(Dwarf_Die *sp_die, void *data)
 {
 	struct __line_walk_param *lw = data;
 
-	lw->retval = __die_walk_funclines(sp_die, lw->callback, lw->data);
+	lw->retval = __die_walk_funclines(sp_die, true, lw->callback, lw->data);
 	if (lw->retval != 0)
 		return DWARF_CB_ABORT;
 
@@ -509,7 +572,11 @@ int die_walk_lines(Dwarf_Die *rt_die, line_walk_callback_t callback, void *data)
 	 * subroutines. We have to check functions list or given function.
 	 */
 	if (rt_die != cu_die)
-		ret = __die_walk_funclines(rt_die, callback, data);
+		/*
+		 * Don't need walk functions recursively, because nested
+		 * inlined functions don't have lines of the specified DIE.
+		 */
+		ret = __die_walk_funclines(rt_die, false, callback, data);
 	else {
 		struct __line_walk_param param = {
 			.callback = callback,
diff --git a/tools/perf/util/dwarf-aux.h b/tools/perf/util/dwarf-aux.h
index bc3b211..c8e491b 100644
--- a/tools/perf/util/dwarf-aux.h
+++ b/tools/perf/util/dwarf-aux.h
@@ -40,6 +40,9 @@ extern bool die_compare_name(Dwarf_Die *dw_die, const char *tname);
 /* Get callsite line number of inline-function instance */
 extern int die_get_call_lineno(Dwarf_Die *in_die);
 
+/* Get callsite file name of inlined function instance */
+extern const char *die_get_call_file(Dwarf_Die *in_die);
+
 /* Get type die */
 extern Dwarf_Die *die_get_type(Dwarf_Die *vr_die, Dwarf_Die *die_mem);
 

[tip:perf/core] perf probe: Fix to walk all inline instances

[tip-bot for Masami Hiramatsu]

Commit-ID:  36c0c588b9ea979b619d6ddced410f9551e4c5fa
Gitweb:     http://git.kernel.org/tip/36c0c588b9ea979b619d6ddced410f9551e4c5fa
Author:     Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
AuthorDate: Thu, 11 Aug 2011 20:02:47 +0900
Committer:  Arnaldo Carvalho de Melo <acme@redhat.com>
CommitDate: Fri, 12 Aug 2011 09:25:38 -0300

perf probe: Fix to walk all inline instances

Fix line-range collector to walk all instances of inlined function,
because some execution paths can be optimized out depending on the
function argument of instances.

E.g.)
inline_func (arg) {
	if (arg)
		do_something;
	else
		do_another;
}

func_A() {
	inline_func(1)
}

func_B() {
	inline_func(0)
}

In this case, func_A may have only do_something code and func_B may have
only do_another.

Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Masami Hiramatsu <masami.hiramatsu@gmail.com>
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/20110811110247.19900.93702.stgit@fedora15
Signed-off-by: Masami Hiramatsu <masami.hiramatsu@gmail.com>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
---
 tools/perf/util/probe-finder.c |    8 +++++++-
 1 files changed, 7 insertions(+), 1 deletions(-)

diff --git a/tools/perf/util/probe-finder.c b/tools/perf/util/probe-finder.c
index 573c723..d6d5768 100644
--- a/tools/perf/util/probe-finder.c
+++ b/tools/perf/util/probe-finder.c
@@ -1393,7 +1393,13 @@ 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);
-	return DWARF_CB_ABORT;	/* No need to find other instances */
+
+	/*
+	 * 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;
 }
 
 /* Search function from function name */

[tip:perf/core] perf probe: Warn when more than one line are given

[tip-bot for Masami Hiramatsu]

Commit-ID:  13e27d7686c457c625242fc2c20be30eef942408
Gitweb:     http://git.kernel.org/tip/13e27d7686c457c625242fc2c20be30eef942408
Author:     Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
AuthorDate: Thu, 11 Aug 2011 20:02:53 +0900
Committer:  Arnaldo Carvalho de Melo <acme@redhat.com>
CommitDate: Fri, 12 Aug 2011 09:27:11 -0300

perf probe: Warn when more than one line are given

Check multiple --lines option and print warning informing that only the
first specified --line option is valid.

Changes from the 1st post:

- Accept only the first option instead of the last.
- Fix warning message according to David's comment.
- Mark as a bugfix.

Cc: David Ahern <dsahern@gmail.com>
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/20110811110253.19900.96192.stgit@fedora15
Signed-off-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
---
 tools/perf/builtin-probe.c |   14 +++++++++++---
 1 files changed, 11 insertions(+), 3 deletions(-)

diff --git a/tools/perf/builtin-probe.c b/tools/perf/builtin-probe.c
index 5f2a5c7..710ae3d 100644
--- a/tools/perf/builtin-probe.c
+++ b/tools/perf/builtin-probe.c
@@ -134,10 +134,18 @@ static int opt_show_lines(const struct option *opt __used,
 {
 	int ret = 0;
 
-	if (str)
-		ret = parse_line_range_desc(str, &params.line_range);
-	INIT_LIST_HEAD(&params.line_range.line_list);
+	if (!str)
+		return 0;
+
+	if (params.show_lines) {
+		pr_warning("Warning: more than one --line options are"
+			   " detected. Only the first one is valid.\n");
+		return 0;
+	}
+
 	params.show_lines = true;
+	ret = parse_line_range_desc(str, &params.line_range);
+	INIT_LIST_HEAD(&params.line_range.line_list);
 
 	return ret;
 }

[tip:perf/core] perf probe: Fix to search local variables in appropriate scope

[tip-bot for Masami Hiramatsu]

Commit-ID:  221d061182b8ff5507d5768aeeecbc74f01c5dfa
Gitweb:     http://git.kernel.org/tip/221d061182b8ff5507d5768aeeecbc74f01c5dfa
Author:     Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
AuthorDate: Thu, 11 Aug 2011 20:02:59 +0900
Committer:  Arnaldo Carvalho de Melo <acme@redhat.com>
CommitDate: Fri, 12 Aug 2011 09:28:45 -0300

perf probe: Fix to search local variables in appropriate scope

Fix perf probe to search local variables in appropriate local inlined
function scope. For example, pre_schedule() has only 2 local variables,
as below;

$ perf probe -L pre_schedule
<pre_schedule@/home/mhiramat/ksrc/linux-2.6/kernel/sched.c:0>
      0  static inline void pre_schedule(struct rq *rq, struct task_struct *prev)
         {
      2         if (prev->sched_class->pre_schedule)
      3                 prev->sched_class->pre_schedule(rq, prev);
         }

However, current perf probe shows 4 local variables on pre_schedule(),
because it searches variables in the caller(schedule()) scope.

$ perf probe -V pre_schedule
Available variables at pre_schedule
        @<schedule+445>
                int     cpu
                long unsigned int*      switch_count
                struct rq*      rq
                struct task_struct*     prev

This patch fixes this issue by searching variables in the local scope of
the instance of inlined function. Here is the result.

$ perf probe -V pre_schedule
Available variables at pre_schedule
        @<schedule+445>
                struct rq*      rq
                struct task_struct*     prev

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/20110811110259.19900.85664.stgit@fedora15
Signed-off-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
---
 tools/perf/util/dwarf-aux.c    |   33 ++++++++++
 tools/perf/util/dwarf-aux.h    |    4 +
 tools/perf/util/probe-finder.c |  132 ++++++++++++++++++++++++++++++++--------
 tools/perf/util/probe-finder.h |    2 +-
 4 files changed, 144 insertions(+), 27 deletions(-)

diff --git a/tools/perf/util/dwarf-aux.c b/tools/perf/util/dwarf-aux.c
index d9b8ad0..425703a 100644
--- a/tools/perf/util/dwarf-aux.c
+++ b/tools/perf/util/dwarf-aux.c
@@ -96,6 +96,39 @@ int cu_find_lineinfo(Dwarf_Die *cu_die, unsigned long addr,
 	return *lineno ?: -ENOENT;
 }
 
+static int __die_find_inline_cb(Dwarf_Die *die_mem, void *data);
+
+/**
+ * cu_walk_functions_at - Walk on function DIEs at given address
+ * @cu_die: A CU DIE
+ * @addr: An address
+ * @callback: A callback which called with found DIEs
+ * @data: A user data
+ *
+ * Walk on function DIEs at given @addr in @cu_die. Passed DIEs
+ * should be subprogram or inlined-subroutines.
+ */
+int cu_walk_functions_at(Dwarf_Die *cu_die, Dwarf_Addr addr,
+		    int (*callback)(Dwarf_Die *, void *), void *data)
+{
+	Dwarf_Die die_mem;
+	Dwarf_Die *sc_die;
+	int ret = -ENOENT;
+
+	/* Inlined function could be recursive. Trace it until fail */
+	for (sc_die = die_find_realfunc(cu_die, addr, &die_mem);
+	     sc_die != NULL;
+	     sc_die = die_find_child(sc_die, __die_find_inline_cb, &addr,
+				     &die_mem)) {
+		ret = callback(sc_die, data);
+		if (ret)
+			break;
+	}
+
+	return ret;
+
+}
+
 /**
  * die_compare_name - Compare diename and tname
  * @dw_die: a DIE
diff --git a/tools/perf/util/dwarf-aux.h b/tools/perf/util/dwarf-aux.h
index c8e491b..6f46106 100644
--- a/tools/perf/util/dwarf-aux.h
+++ b/tools/perf/util/dwarf-aux.h
@@ -34,6 +34,10 @@ extern const char *cu_get_comp_dir(Dwarf_Die *cu_die);
 extern int cu_find_lineinfo(Dwarf_Die *cudie, unsigned long addr,
 			    const char **fname, int *lineno);
 
+/* Walk on funcitons at given address */
+extern int cu_walk_functions_at(Dwarf_Die *cu_die, Dwarf_Addr addr,
+			int (*callback)(Dwarf_Die *, void *), void *data);
+
 /* Compare diename and tname */
 extern bool die_compare_name(Dwarf_Die *dw_die, const char *tname);
 
diff --git a/tools/perf/util/probe-finder.c b/tools/perf/util/probe-finder.c
index d6d5768..5c83b7d 100644
--- a/tools/perf/util/probe-finder.c
+++ b/tools/perf/util/probe-finder.c
@@ -612,8 +612,8 @@ static int convert_variable(Dwarf_Die *vr_die, struct probe_finder *pf)
 	return ret;
 }
 
-/* Find a variable in a subprogram die */
-static int find_variable(Dwarf_Die *sp_die, struct probe_finder *pf)
+/* Find a variable in a scope DIE */
+static int find_variable(Dwarf_Die *sc_die, struct probe_finder *pf)
 {
 	Dwarf_Die vr_die, *scopes;
 	char buf[32], *ptr;
@@ -655,11 +655,11 @@ static int find_variable(Dwarf_Die *sp_die, struct probe_finder *pf)
 	pr_debug("Searching '%s' variable in context.\n",
 		 pf->pvar->var);
 	/* Search child die for local variables and parameters. */
-	if (die_find_variable_at(sp_die, pf->pvar->var, pf->addr, &vr_die))
+	if (die_find_variable_at(sc_die, pf->pvar->var, pf->addr, &vr_die))
 		ret = convert_variable(&vr_die, pf);
 	else {
 		/* Search upper class */
-		nscopes = dwarf_getscopes_die(sp_die, &scopes);
+		nscopes = dwarf_getscopes_die(sc_die, &scopes);
 		ret = -ENOENT;
 		while (nscopes-- > 1) {
 			pr_debug("Searching variables in %s\n",
@@ -717,26 +717,30 @@ static int convert_to_trace_point(Dwarf_Die *sp_die, Dwarf_Addr paddr,
 	return 0;
 }
 
-/* Call probe_finder callback with real subprogram DIE */
-static int call_probe_finder(Dwarf_Die *sp_die, struct probe_finder *pf)
+/* Call probe_finder callback with scope DIE */
+static int call_probe_finder(Dwarf_Die *sc_die, struct probe_finder *pf)
 {
-	Dwarf_Die die_mem;
 	Dwarf_Attribute fb_attr;
 	size_t nops;
 	int ret;
 
-	/* If no real subprogram, find a real one */
-	if (!sp_die || dwarf_tag(sp_die) != DW_TAG_subprogram) {
-		sp_die = die_find_realfunc(&pf->cu_die, pf->addr, &die_mem);
-		if (!sp_die) {
+	if (!sc_die) {
+		pr_err("Caller must pass a scope DIE. Program error.\n");
+		return -EINVAL;
+	}
+
+	/* If not a real subprogram, find a real one */
+	if (dwarf_tag(sc_die) != DW_TAG_subprogram) {
+		if (!die_find_realfunc(&pf->cu_die, pf->addr, &pf->sp_die)) {
 			pr_warning("Failed to find probe point in any "
 				   "functions.\n");
 			return -ENOENT;
 		}
-	}
+	} else
+		memcpy(&pf->sp_die, sc_die, sizeof(Dwarf_Die));
 
-	/* Get the frame base attribute/ops */
-	dwarf_attr(sp_die, DW_AT_frame_base, &fb_attr);
+	/* Get the frame base attribute/ops from subprogram */
+	dwarf_attr(&pf->sp_die, DW_AT_frame_base, &fb_attr);
 	ret = dwarf_getlocation_addr(&fb_attr, pf->addr, &pf->fb_ops, &nops, 1);
 	if (ret <= 0 || nops == 0) {
 		pf->fb_ops = NULL;
@@ -754,7 +758,7 @@ static int call_probe_finder(Dwarf_Die *sp_die, struct probe_finder *pf)
 	}
 
 	/* Call finder's callback handler */
-	ret = pf->callback(sp_die, pf);
+	ret = pf->callback(sc_die, pf);
 
 	/* *pf->fb_ops will be cached in libdw. Don't free it. */
 	pf->fb_ops = NULL;
@@ -762,17 +766,82 @@ static int call_probe_finder(Dwarf_Die *sp_die, struct probe_finder *pf)
 	return ret;
 }
 
+struct find_scope_param {
+	const char *function;
+	const char *file;
+	int line;
+	int diff;
+	Dwarf_Die *die_mem;
+	bool found;
+};
+
+static int find_best_scope_cb(Dwarf_Die *fn_die, void *data)
+{
+	struct find_scope_param *fsp = data;
+	const char *file;
+	int lno;
+
+	/* Skip if declared file name does not match */
+	if (fsp->file) {
+		file = dwarf_decl_file(fn_die);
+		if (!file || strcmp(fsp->file, file) != 0)
+			return 0;
+	}
+	/* If the function name is given, that's what user expects */
+	if (fsp->function) {
+		if (die_compare_name(fn_die, fsp->function)) {
+			memcpy(fsp->die_mem, fn_die, sizeof(Dwarf_Die));
+			fsp->found = true;
+			return 1;
+		}
+	} else {
+		/* With the line number, find the nearest declared DIE */
+		dwarf_decl_line(fn_die, &lno);
+		if (lno < fsp->line && fsp->diff > fsp->line - lno) {
+			/* Keep a candidate and continue */
+			fsp->diff = fsp->line - lno;
+			memcpy(fsp->die_mem, fn_die, sizeof(Dwarf_Die));
+			fsp->found = true;
+		}
+	}
+	return 0;
+}
+
+/* Find an appropriate scope fits to given conditions */
+static Dwarf_Die *find_best_scope(struct probe_finder *pf, Dwarf_Die *die_mem)
+{
+	struct find_scope_param fsp = {
+		.function = pf->pev->point.function,
+		.file = pf->fname,
+		.line = pf->lno,
+		.diff = INT_MAX,
+		.die_mem = die_mem,
+		.found = false,
+	};
+
+	cu_walk_functions_at(&pf->cu_die, pf->addr, find_best_scope_cb, &fsp);
+
+	return fsp.found ? die_mem : NULL;
+}
+
 static int probe_point_line_walker(const char *fname, int lineno,
 				   Dwarf_Addr addr, void *data)
 {
 	struct probe_finder *pf = data;
+	Dwarf_Die *sc_die, die_mem;
 	int ret;
 
 	if (lineno != pf->lno || strtailcmp(fname, pf->fname) != 0)
 		return 0;
 
 	pf->addr = addr;
-	ret = call_probe_finder(NULL, pf);
+	sc_die = find_best_scope(pf, &die_mem);
+	if (!sc_die) {
+		pr_warning("Failed to find scope of probe point.\n");
+		return -ENOENT;
+	}
+
+	ret = call_probe_finder(sc_die, pf);
 
 	/* Continue if no error, because the line will be in inline function */
 	return ret < 0 ? ret : 0;
@@ -826,6 +895,7 @@ static int probe_point_lazy_walker(const char *fname, int lineno,
 				   Dwarf_Addr addr, void *data)
 {
 	struct probe_finder *pf = data;
+	Dwarf_Die *sc_die, die_mem;
 	int ret;
 
 	if (!line_list__has_line(&pf->lcache, lineno) ||
@@ -835,7 +905,14 @@ static int probe_point_lazy_walker(const char *fname, int lineno,
 	pr_debug("Probe line found: line:%d addr:0x%llx\n",
 		 lineno, (unsigned long long)addr);
 	pf->addr = addr;
-	ret = call_probe_finder(NULL, pf);
+	pf->lno = lineno;
+	sc_die = find_best_scope(pf, &die_mem);
+	if (!sc_die) {
+		pr_warning("Failed to find scope of probe point.\n");
+		return -ENOENT;
+	}
+
+	ret = call_probe_finder(sc_die, pf);
 
 	/*
 	 * Continue if no error, because the lazy pattern will match
@@ -1059,7 +1136,7 @@ found:
 }
 
 /* Add a found probe point into trace event list */
-static int add_probe_trace_event(Dwarf_Die *sp_die, struct probe_finder *pf)
+static int add_probe_trace_event(Dwarf_Die *sc_die, struct probe_finder *pf)
 {
 	struct trace_event_finder *tf =
 			container_of(pf, struct trace_event_finder, pf);
@@ -1074,8 +1151,9 @@ static int add_probe_trace_event(Dwarf_Die *sp_die, struct probe_finder *pf)
 	}
 	tev = &tf->tevs[tf->ntevs++];
 
-	ret = convert_to_trace_point(sp_die, pf->addr, pf->pev->point.retprobe,
-				     &tev->point);
+	/* Trace point should be converted from subprogram DIE */
+	ret = convert_to_trace_point(&pf->sp_die, pf->addr,
+				     pf->pev->point.retprobe, &tev->point);
 	if (ret < 0)
 		return ret;
 
@@ -1090,7 +1168,8 @@ static int add_probe_trace_event(Dwarf_Die *sp_die, struct probe_finder *pf)
 	for (i = 0; i < pf->pev->nargs; i++) {
 		pf->pvar = &pf->pev->args[i];
 		pf->tvar = &tev->args[i];
-		ret = find_variable(sp_die, pf);
+		/* Variable should be found from scope DIE */
+		ret = find_variable(sc_die, pf);
 		if (ret != 0)
 			return ret;
 	}
@@ -1158,7 +1237,7 @@ static int collect_variables_cb(Dwarf_Die *die_mem, void *data)
 }
 
 /* Add a found vars into available variables list */
-static int add_available_vars(Dwarf_Die *sp_die, struct probe_finder *pf)
+static int add_available_vars(Dwarf_Die *sc_die, struct probe_finder *pf)
 {
 	struct available_var_finder *af =
 			container_of(pf, struct available_var_finder, pf);
@@ -1173,8 +1252,9 @@ static int add_available_vars(Dwarf_Die *sp_die, struct probe_finder *pf)
 	}
 	vl = &af->vls[af->nvls++];
 
-	ret = convert_to_trace_point(sp_die, pf->addr, pf->pev->point.retprobe,
-				     &vl->point);
+	/* Trace point should be converted from subprogram DIE */
+	ret = convert_to_trace_point(&pf->sp_die, pf->addr,
+				     pf->pev->point.retprobe, &vl->point);
 	if (ret < 0)
 		return ret;
 
@@ -1186,14 +1266,14 @@ static int add_available_vars(Dwarf_Die *sp_die, struct probe_finder *pf)
 	if (vl->vars == NULL)
 		return -ENOMEM;
 	af->child = true;
-	die_find_child(sp_die, collect_variables_cb, (void *)af, &die_mem);
+	die_find_child(sc_die, collect_variables_cb, (void *)af, &die_mem);
 
 	/* Find external variables */
 	if (!af->externs)
 		goto out;
 	/* Don't need to search child DIE for externs. */
 	af->child = false;
-	nscopes = dwarf_getscopes_die(sp_die, &scopes);
+	nscopes = dwarf_getscopes_die(sc_die, &scopes);
 	while (nscopes-- > 1)
 		die_find_child(&scopes[nscopes], collect_variables_cb,
 			       (void *)af, &die_mem);
diff --git a/tools/perf/util/probe-finder.h b/tools/perf/util/probe-finder.h
index c478b42..1132c8f 100644
--- a/tools/perf/util/probe-finder.h
+++ b/tools/perf/util/probe-finder.h
@@ -57,7 +57,7 @@ struct probe_finder {
 	struct perf_probe_event	*pev;		/* Target probe event */
 
 	/* Callback when a probe point is found */
-	int (*callback)(Dwarf_Die *sp_die, struct probe_finder *pf);
+	int (*callback)(Dwarf_Die *sc_die, struct probe_finder *pf);
 
 	/* For function searching */
 	int			lno;		/* Line number */

[tip:perf/core] perf probe: Avoid searching variables in intermediate scopes

[tip-bot for Masami Hiramatsu]

Commit-ID:  f182e3e13ca71b64b40fab1aef31fa6a78271648
Gitweb:     http://git.kernel.org/tip/f182e3e13ca71b64b40fab1aef31fa6a78271648
Author:     Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
AuthorDate: Thu, 11 Aug 2011 20:03:05 +0900
Committer:  Arnaldo Carvalho de Melo <acme@redhat.com>
CommitDate: Fri, 12 Aug 2011 09:29:34 -0300

perf probe: Avoid searching variables in intermediate scopes

Fix variable searching logic to search one in inner than local scope or
global(CU) scope. In the other words, skip searching in intermediate
scopes.

e.g., in the following code,

int var1;

void inline infunc(int i)
{
    i++;   <--- [A]
}

void func(void)
{
   int var1, var2;
   infunc(var2);
}

At [A], "var1" should point the global variable "var1", however, if user
mis-typed as "var2", variable search should be failed. However, current
logic searches variable infunc() scope, global scope, and then func()
scope. Thus, it can find "var2" variable in func() scope. This may not
be what user expects.

So, it would better not search outer scopes except outermost (compile
unit) scope which contains only global variables, when it failed to find
given variable in local scope.

E.g.

Without this:
$ perf probe -V pre_schedule --externs > without.vars

With this:
$ perf probe -V pre_schedule --externs > with.vars

Check the diff:
$ diff without.vars with.vars
88d87
<               int     cpu
133d131
<               long unsigned int*      switch_count

These vars are actually in the scope of schedule(), the caller of
pre_schedule().

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/20110811110305.19900.94374.stgit@fedora15
Signed-off-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
---
 tools/perf/util/probe-finder.c |   44 +++++++++++----------------------------
 1 files changed, 13 insertions(+), 31 deletions(-)

diff --git a/tools/perf/util/probe-finder.c b/tools/perf/util/probe-finder.c
index 5c83b7d..114542a 100644
--- a/tools/perf/util/probe-finder.c
+++ b/tools/perf/util/probe-finder.c
@@ -615,9 +615,9 @@ static int convert_variable(Dwarf_Die *vr_die, struct probe_finder *pf)
 /* Find a variable in a scope DIE */
 static int find_variable(Dwarf_Die *sc_die, struct probe_finder *pf)
 {
-	Dwarf_Die vr_die, *scopes;
+	Dwarf_Die vr_die;
 	char buf[32], *ptr;
-	int ret, nscopes;
+	int ret = 0;
 
 	if (!is_c_varname(pf->pvar->var)) {
 		/* Copy raw parameters */
@@ -652,29 +652,16 @@ static int find_variable(Dwarf_Die *sc_die, struct probe_finder *pf)
 	if (pf->tvar->name == NULL)
 		return -ENOMEM;
 
-	pr_debug("Searching '%s' variable in context.\n",
-		 pf->pvar->var);
+	pr_debug("Searching '%s' variable in context.\n", pf->pvar->var);
 	/* Search child die for local variables and parameters. */
-	if (die_find_variable_at(sc_die, pf->pvar->var, pf->addr, &vr_die))
-		ret = convert_variable(&vr_die, pf);
-	else {
-		/* Search upper class */
-		nscopes = dwarf_getscopes_die(sc_die, &scopes);
-		ret = -ENOENT;
-		while (nscopes-- > 1) {
-			pr_debug("Searching variables in %s\n",
-				 dwarf_diename(&scopes[nscopes]));
-			/* We should check this scope, so give dummy address */
-			if (die_find_variable_at(&scopes[nscopes],
-						 pf->pvar->var, 0,
-						 &vr_die)) {
-				ret = convert_variable(&vr_die, pf);
-				break;
-			}
-		}
-		if (scopes)
-			free(scopes);
+	if (!die_find_variable_at(sc_die, pf->pvar->var, pf->addr, &vr_die)) {
+		/* Search again in global variables */
+		if (!die_find_variable_at(&pf->cu_die, pf->pvar->var, 0, &vr_die))
+			ret = -ENOENT;
 	}
+	if (ret == 0)
+		ret = convert_variable(&vr_die, pf);
+
 	if (ret < 0)
 		pr_warning("Failed to find '%s' in this function.\n",
 			   pf->pvar->var);
@@ -1242,8 +1229,8 @@ static int add_available_vars(Dwarf_Die *sc_die, struct probe_finder *pf)
 	struct available_var_finder *af =
 			container_of(pf, struct available_var_finder, pf);
 	struct variable_list *vl;
-	Dwarf_Die die_mem, *scopes = NULL;
-	int ret, nscopes;
+	Dwarf_Die die_mem;
+	int ret;
 
 	/* Check number of tevs */
 	if (af->nvls == af->max_vls) {
@@ -1273,12 +1260,7 @@ static int add_available_vars(Dwarf_Die *sc_die, struct probe_finder *pf)
 		goto out;
 	/* Don't need to search child DIE for externs. */
 	af->child = false;
-	nscopes = dwarf_getscopes_die(sc_die, &scopes);
-	while (nscopes-- > 1)
-		die_find_child(&scopes[nscopes], collect_variables_cb,
-			       (void *)af, &die_mem);
-	if (scopes)
-		free(scopes);
+	die_find_child(&pf->cu_die, collect_variables_cb, (void *)af, &die_mem);
 
 out:
 	if (strlist__empty(vl->vars)) {

[tip:perf/core] perf probe: Search concrete out-of-line instances

[tip-bot for Masami Hiramatsu]

Commit-ID:  db0d2c6420eeb8fd669bac84d72f1ab828bbaa64
Gitweb:     http://git.kernel.org/tip/db0d2c6420eeb8fd669bac84d72f1ab828bbaa64
Author:     Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
AuthorDate: Thu, 11 Aug 2011 20:03:11 +0900
Committer:  Arnaldo Carvalho de Melo <acme@redhat.com>
CommitDate: Fri, 12 Aug 2011 09:32:10 -0300

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: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
---
 tools/perf/util/dwarf-aux.c    |   58 ++++++++++++++++++++++++++++++++++++++++
 tools/perf/util/dwarf-aux.h    |    4 +++
 tools/perf/util/probe-finder.c |   56 ++++++++++++++------------------------
 3 files changed, 83 insertions(+), 35 deletions(-)

diff --git a/tools/perf/util/dwarf-aux.c b/tools/perf/util/dwarf-aux.c
index 425703a..d0f4048 100644
--- a/tools/perf/util/dwarf-aux.c
+++ b/tools/perf/util/dwarf-aux.c
@@ -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;
diff --git a/tools/perf/util/dwarf-aux.h b/tools/perf/util/dwarf-aux.h
index 6f46106..6ce1717 100644
--- a/tools/perf/util/dwarf-aux.h
+++ b/tools/perf/util/dwarf-aux.h
@@ -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);
diff --git a/tools/perf/util/probe-finder.c b/tools/perf/util/probe-finder.c
index 114542a..555fc38 100644
--- a/tools/perf/util/probe-finder.c
+++ b/tools/perf/util/probe-finder.c
@@ -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;
 	}

[tip:perf/core] perf probe: Filter out redundant inline-instances

[tip-bot for Masami Hiramatsu]

Commit-ID:  3f4460a28fb2f73df6c32c3a305797abc01c0f9c
Gitweb:     http://git.kernel.org/tip/3f4460a28fb2f73df6c32c3a305797abc01c0f9c
Author:     Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
AuthorDate: Thu, 11 Aug 2011 20:03:18 +0900
Committer:  Arnaldo Carvalho de Melo <acme@redhat.com>
CommitDate: Fri, 12 Aug 2011 09:34:35 -0300

perf probe: Filter out redundant inline-instances

With gcc4.6, some instances of concrete inlined function looks redundant
and broken, because it appears inside of a concrete instance and its
call_file and call_line are same as the original abstruct's decl_file
and decl_line respectively.

e.g.
 [  d1aa]    subprogram
             external             (flag) Yes
             name                 (strp) "add_timer"
             decl_file            (data1) 2		;here is original
             decl_line            (data2) 847		;line and file
             prototyped           (flag) Yes
             inline               (data1) inlined (1)
             sibling              (ref4) [  d1c6]
...
 [ 11d84]    subprogram
             abstract_origin      (ref4) [  d1aa]	; concrete instance
             low_pc               (addr) .text+0x000000000000246f <add_timer>
             high_pc              (addr) .text+0x000000000000248b <mod_timer_pending>
             frame_base           (block1)               [   0] call_frame_cfa
             sibling              (ref4) [ 11dd9]
 [ 11d9f]      formal_parameter
               abstract_origin      (ref4) [  d1b9]
               location             (data4) location list [  701b]
 [ 11da8]      inlined_subroutine
               abstract_origin      (ref4) [  d1aa]	; redundant instance
               low_pc               (addr) .text+0x000000000000247e <add_timer+0xf>
               high_pc              (addr) .text+0x0000000000002480 <add_timer+0x11>
               call_file            (data1) 2		; call line and file
               call_line            (data2) 847		; are same as above

Those redundant instances leads unwilling results;

e.g. find probe points inside of functions even if we specify
a function entry as below;

$ perf probe -V add_timer
Available variables at add_timer
        @<add_timer+0>
                struct timer_list*      timer
        @<add_timer+15>
                (No matched variables)

So, this filters out those redundant instances based on call-site and
decl-site information.

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/20110811110317.19900.59525.stgit@fedora15
Signed-off-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
---
 tools/perf/util/dwarf-aux.c |   22 ++++++++++++++++++++++
 1 files changed, 22 insertions(+), 0 deletions(-)

diff --git a/tools/perf/util/dwarf-aux.c b/tools/perf/util/dwarf-aux.c
index d0f4048..ee51e9b 100644
--- a/tools/perf/util/dwarf-aux.c
+++ b/tools/perf/util/dwarf-aux.c
@@ -307,6 +307,17 @@ static int die_get_call_fileno(Dwarf_Die *in_die)
 		return -ENOENT;
 }
 
+/* Get the declared file index number in CU DIE */
+static int die_get_decl_fileno(Dwarf_Die *pdie)
+{
+	Dwarf_Sword idx;
+
+	if (die_get_attr_sdata(pdie, DW_AT_decl_file, &idx) == 0)
+		return (int)idx;
+	else
+		return -ENOENT;
+}
+
 /**
  * die_get_call_file - Get callsite file name of inlined function instance
  * @in_die: a DIE of an inlined function instance
@@ -467,6 +478,7 @@ static int __die_walk_instances_cb(Dwarf_Die *inst, void *data)
 	Dwarf_Die origin_mem;
 	Dwarf_Attribute *attr;
 	Dwarf_Die *origin;
+	int tmp;
 
 	attr = dwarf_attr(inst, DW_AT_abstract_origin, &attr_mem);
 	if (attr == NULL)
@@ -476,6 +488,16 @@ static int __die_walk_instances_cb(Dwarf_Die *inst, void *data)
 	if (origin == NULL || origin->addr != iwp->addr)
 		return DIE_FIND_CB_CONTINUE;
 
+	/* Ignore redundant instances */
+	if (dwarf_tag(inst) == DW_TAG_inlined_subroutine) {
+		dwarf_decl_line(origin, &tmp);
+		if (die_get_call_lineno(inst) == tmp) {
+			tmp = die_get_decl_fileno(origin);
+			if (die_get_call_fileno(inst) == tmp)
+				return DIE_FIND_CB_CONTINUE;
+		}
+	}
+
 	iwp->retval = iwp->callback(inst, iwp->data);
 
 	return (iwp->retval) ? DIE_FIND_CB_END : DIE_FIND_CB_CONTINUE;