Commit 91e2f539 authored by Masami Hiramatsu's avatar Masami Hiramatsu Committed by Arnaldo Carvalho de Melo
Browse files

perf probe: Fix to show function entry line as probe-able 



Fix die_walk_lines() to list the function entry line correctly.  Since
the dwarf_entrypc() does not return the entry pc if the DIE has only
range attribute, __die_walk_funclines() fails to list the declaration
line (entry line) in that case.

To solve this issue, this introduces die_entrypc() which correctly
returns the entry PC (the first address range) even if the DIE has only
range attribute. With this fix die_walk_lines() shows the function entry
line is able to probe correctly.

Fixes: 4cc9cec6 ("perf probe: Introduce lines walker interface")
Signed-off-by: default avatarMasami Hiramatsu <mhiramat@kernel.org>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Link: http://lore.kernel.org/lkml/157190837419.1859.4619125803596816752.stgit@devnote2


Signed-off-by: default avatarArnaldo Carvalho de Melo <acme@redhat.com>
parent acb6a704

tools/perf/util/dwarf-aux.c

+23 −1
Original line number Diff line number Diff line
@@ -307,6 +307,28 @@ bool die_is_func_def(Dwarf_Die *dw_die) 
		dwarf_attr(dw_die, DW_AT_declaration, &attr) == NULL);

}



/**

 * die_entrypc - Returns entry PC (the lowest address) of a DIE

 * @dw_die: a DIE

 * @addr: where to store entry PC

 *

 * Since dwarf_entrypc() does not return entry PC if the DIE has only address

 * range, we have to use this to retrieve the lowest address from the address

 * range attribute.

 */

int die_entrypc(Dwarf_Die *dw_die, Dwarf_Addr *addr)

{

	Dwarf_Addr base, end;



	if (!addr)

		return -EINVAL;



	if (dwarf_entrypc(dw_die, addr) == 0)

		return 0;



	return dwarf_ranges(dw_die, 0, &base, addr, &end) < 0 ? -ENOENT : 0;

}



/**

 * die_is_func_instance - Ensure that this DIE is an instance of a subprogram

 * @dw_die: a DIE
@@ -713,7 +735,7 @@ static int __die_walk_funclines(Dwarf_Die *sp_die, bool recursive, 
	/* Handle function declaration line */

	fname = dwarf_decl_file(sp_die);

	if (fname && dwarf_decl_line(sp_die, &lineno) == 0 &&

	    dwarf_entrypc(sp_die, &addr) == 0) {

	    die_entrypc(sp_die, &addr) == 0) {

		lw.retval = callback(fname, lineno, addr, data);

		if (lw.retval != 0)

			goto done;

tools/perf/util/dwarf-aux.h

+3 −0
Original line number Diff line number Diff line
@@ -29,6 +29,9 @@ int cu_walk_functions_at(Dwarf_Die *cu_die, Dwarf_Addr addr, 
/* Get DW_AT_linkage_name (should be NULL for C binary) */

const char *die_get_linkage_name(Dwarf_Die *dw_die);



/* Get the lowest PC in DIE (including range list) */

int die_entrypc(Dwarf_Die *dw_die, Dwarf_Addr *addr);



/* Ensure that this DIE is a subprogram and definition (not declaration) */

bool die_is_func_def(Dwarf_Die *dw_die);

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