3.16.82-rc1 review patch. If anyone has any objections, please let me know.
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From: Masami Hiramatsu mhiramat@kernel.org
commit 91e2f539eeda26ab00bd03fae8dc434c128c85ed upstream.
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: 4cc9cec636e7 ("perf probe: Introduce lines walker interface") Signed-off-by: Masami 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@devn... Signed-off-by: Arnaldo Carvalho de Melo acme@redhat.com Signed-off-by: Ben Hutchings ben@decadent.org.uk --- tools/perf/util/dwarf-aux.c | 24 +++++++++++++++++++++++- tools/perf/util/dwarf-aux.h | 3 +++ 2 files changed, 26 insertions(+), 1 deletion(-)
--- a/tools/perf/util/dwarf-aux.c +++ b/tools/perf/util/dwarf-aux.c @@ -278,6 +278,28 @@ bool die_is_func_def(Dwarf_Die *dw_die) }
/** + * 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 * @@ -647,7 +669,7 @@ static int __die_walk_funclines(Dwarf_Di /* 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; --- 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 *c extern int cu_walk_functions_at(Dwarf_Die *cu_die, Dwarf_Addr addr, int (*callback)(Dwarf_Die *, void *), void *data);
+/* 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) */ extern bool die_is_func_def(Dwarf_Die *dw_die);