perf-probe: Fix to show lines of sys_ functions correctly

From: Masami Hiramatsu [mailto:[email protected]]

"perf probe --lines sys_poll" shows only the first line of sys_poll, because the SYSCALL_DEFINE macro
----
SYSCALL_DEFINE*(foo,...)
{
body;
}
----
is expanded as below (on debuginfo)

----
static inline int SYSC_foo(...)
{
body;
}
int SyS_foo(...) <- is an alias of sys_foo.
{
return SYSC_foo(...);
}
----

So, "perf probe --lines sys_foo" decodes SyS_foo function and it also skips inlined functions(SYSC_foo) inside the target function because those functions are usually defined somewhere else.

To fix this issue, this fix checks whether the inlined function is defined at the same point of the target function, and if so, it doesn't skip the inline function.

Reported-by Arnaldo Carvalho de Melo <[email protected]>

Signed-off-by Masami Hiramatsu <[email protected]>

---
Changes in v2
- Fix to add a brace to if statement.

---
 tools/perf/util/dwarf-aux.c |   21 +++++++++++++++------
 1 file changed, 15 insertions(+), 6 deletions(-)

tools/perf/util/dwarf-aux.c +8 -6

index 57f3ef4..a509aa84 100644
@@ -734,15 +734,18 @@ int die_walk_lines(Dwarf_Die *rt_die, line_walk_callback_t callback, void *data)
 	Dwarf_Lines *lines;
 	Dwarf_Line *line;
 	Dwarf_Addr addr;
-	const char *fname;
+	const char *fname, *decf = NULL;
 	int lineno, ret = 0;
+	int decl = 0, inl;
 	Dwarf_Die die_mem, *cu_die;
 	size_t nlines, i;
 
 	/* Get the CU die */
-	if (dwarf_tag(rt_die) != DW_TAG_compile_unit)
+	if (dwarf_tag(rt_die) != DW_TAG_compile_unit) {
 		cu_die = dwarf_diecu(rt_die, &die_mem, NULL, NULL);
-	else
+		dwarf_decl_line(rt_die, &decl);
+		decf = dwarf_decl_file(rt_die);
+	} else
 		cu_die = rt_die;
 	if (!cu_die) {
 		pr_debug2("Failed to get CU from given DIE.\n");

@@ -767,15 +770,21 @@ int die_walk_lines(Dwarf_Die *rt_die, line_walk_callback_t callback, void *data)
 			continue;
 		}
 		/* Filter lines based on address */
-		if (rt_die != cu_die)
+		if (rt_die != cu_die) {
 			/*
 			 * Address filtering
 			 * The line is included in given function, and
 			 * no inline block includes it.
 			 */
-			if (!dwarf_haspc(rt_die, addr) ||
-			    die_find_inlinefunc(rt_die, addr, &die_mem))
+			if (!dwarf_haspc(rt_die, addr))
 				continue;