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

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 <>
Cc: Jiri Olsa <>
Cc: Namhyung Kim <>
Link: default avatarArnaldo Carvalho de Melo <>
parent acb6a704
......@@ -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;
......@@ -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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