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Subject[tip:perf/urgent] perf probe: Fix finder to find lines of given function
Commit-ID:  0dbb1cac1dbdddf64cdd0f972c062a26484b7177
Gitweb: http://git.kernel.org/tip/0dbb1cac1dbdddf64cdd0f972c062a26484b7177
Author: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
AuthorDate: Mon, 23 Apr 2012 12:24:36 +0900
Committer: Arnaldo Carvalho de Melo <acme@redhat.com>
CommitDate: Thu, 19 Sep 2013 11:35:05 -0300

perf probe: Fix finder to find lines of given function

The commit ba28c59bc9ed8fb7b9a753cd88ee54a2c4f6265b fixed a declaration
entry bug in probe_point_search_cb(). There are same bugs in line
finder and call_probe_finder(). This introduces a new dwarf utility
function to determine given DIE is a function definition, not
declaration.

Signed-off-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
Cc: Prashanth Nageshappa <prashanth@linux.vnet.ibm.com>
Cc: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: yrl.pp-manager.tt@hitachi.com
Link: http://lkml.kernel.org/r/20120423032435.8737.80064.stgit@localhost.localdomain
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
---
tools/perf/util/dwarf-aux.c | 19 +++++++++++++++++++
tools/perf/util/dwarf-aux.h | 3 +++
tools/perf/util/probe-finder.c | 12 +++++-------
3 files changed, 27 insertions(+), 7 deletions(-)

diff --git a/tools/perf/util/dwarf-aux.c b/tools/perf/util/dwarf-aux.c
index 3e5f543..e23bde1 100644
--- a/tools/perf/util/dwarf-aux.c
+++ b/tools/perf/util/dwarf-aux.c
@@ -263,6 +263,21 @@ bool die_is_signed_type(Dwarf_Die *tp_die)
}

/**
+ * die_is_func_def - Ensure that this DIE is a subprogram and definition
+ * @dw_die: a DIE
+ *
+ * Ensure that this DIE is a subprogram and NOT a declaration. This
+ * returns true if @dw_die is a function definition.
+ **/
+bool die_is_func_def(Dwarf_Die *dw_die)
+{
+ Dwarf_Attribute attr;
+
+ return (dwarf_tag(dw_die) == DW_TAG_subprogram &&
+ dwarf_attr(dw_die, DW_AT_declaration, &attr) == NULL);
+}
+
+/**
* die_get_data_member_location - Get the data-member offset
* @mb_die: a DIE of a member of a data structure
* @offs: The offset of the member in the data structure
@@ -392,6 +407,10 @@ static int __die_search_func_cb(Dwarf_Die *fn_die, void *data)
{
struct __addr_die_search_param *ad = data;

+ /*
+ * Since a declaration entry doesn't has given pc, this always returns
+ * function definition entry.
+ */
if (dwarf_tag(fn_die) == DW_TAG_subprogram &&
dwarf_haspc(fn_die, ad->addr)) {
memcpy(ad->die_mem, fn_die, sizeof(Dwarf_Die));
diff --git a/tools/perf/util/dwarf-aux.h b/tools/perf/util/dwarf-aux.h
index 6ce1717..8658d41 100644
--- a/tools/perf/util/dwarf-aux.h
+++ b/tools/perf/util/dwarf-aux.h
@@ -38,6 +38,9 @@ extern int cu_find_lineinfo(Dwarf_Die *cudie, unsigned long addr,
extern int cu_walk_functions_at(Dwarf_Die *cu_die, Dwarf_Addr addr,
int (*callback)(Dwarf_Die *, void *), void *data);

+/* Ensure that this DIE is a subprogram and definition (not declaration) */
+extern bool die_is_func_def(Dwarf_Die *dw_die);
+
/* 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 be03293..20c7299 100644
--- a/tools/perf/util/probe-finder.c
+++ b/tools/perf/util/probe-finder.c
@@ -734,7 +734,7 @@ static int call_probe_finder(Dwarf_Die *sc_die, struct probe_finder *pf)
}

/* If not a real subprogram, find a real one */
- if (dwarf_tag(sc_die) != DW_TAG_subprogram) {
+ if (!die_is_func_def(sc_die)) {
if (!die_find_realfunc(&pf->cu_die, pf->addr, &pf->sp_die)) {
pr_warning("Failed to find probe point in any "
"functions.\n");
@@ -980,12 +980,10 @@ static int probe_point_search_cb(Dwarf_Die *sp_die, void *data)
struct dwarf_callback_param *param = data;
struct probe_finder *pf = param->data;
struct perf_probe_point *pp = &pf->pev->point;
- Dwarf_Attribute attr;

/* Check tag and diename */
- if (dwarf_tag(sp_die) != DW_TAG_subprogram ||
- !die_compare_name(sp_die, pp->function) ||
- dwarf_attr(sp_die, DW_AT_declaration, &attr))
+ if (!die_is_func_def(sp_die) ||
+ !die_compare_name(sp_die, pp->function))
return DWARF_CB_OK;

/* Check declared file */
@@ -1474,7 +1472,7 @@ static int line_range_inline_cb(Dwarf_Die *in_die, void *data)
return 0;
}

-/* Search function from function name */
+/* Search function definition from function name */
static int line_range_search_cb(Dwarf_Die *sp_die, void *data)
{
struct dwarf_callback_param *param = data;
@@ -1485,7 +1483,7 @@ static int line_range_search_cb(Dwarf_Die *sp_die, void *data)
if (lr->file && strtailcmp(lr->file, dwarf_decl_file(sp_die)))
return DWARF_CB_OK;

- if (dwarf_tag(sp_die) == DW_TAG_subprogram &&
+ if (die_is_func_def(sp_die) &&
die_compare_name(sp_die, lr->function)) {
lf->fname = dwarf_decl_file(sp_die);
dwarf_decl_line(sp_die, &lr->offset);

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