[PATCH v1 06/11] perf annotate-data: Collect global variables without name

Zecheng Li posted 11 patches 1 week, 6 days ago
[PATCH v1 06/11] perf annotate-data: Collect global variables without name
Posted by Zecheng Li 1 week, 6 days ago
Previously, global_var__collect() required get_global_var_info() to
succeed (i.e., the variable must have a symbol name) before caching a
global variable. This prevented variables that exist in DWARF but lack
symbol table coverage from being cached.

Remove the symbol table requirement since DW_OP_addr already provides
the variable's address directly from DWARF. The symbol table lookup is
now optional to obtain the variable name when available.

Also remove the var_offset != 0 check, which was intended to skip
variables where the access address doesn't match the symbol start.
The symbol table lookup is now optional and I found removing this check
has no effect on the annotation results for both kernel and userspace
programs.

Test results show improved annotation coverage especially for userspace
programs with RIP-relative addressing instructions.

Signed-off-by: Zecheng Li <zli94@ncsu.edu>
---
 tools/perf/util/annotate-data.c | 7 +------
 1 file changed, 1 insertion(+), 6 deletions(-)

diff --git a/tools/perf/util/annotate-data.c b/tools/perf/util/annotate-data.c
index 8ea3e8b024e8..970238bc81b7 100644
--- a/tools/perf/util/annotate-data.c
+++ b/tools/perf/util/annotate-data.c
@@ -774,12 +774,7 @@ static void global_var__collect(struct data_loc_info *dloc)
 			if (!dwarf_offdie(dwarf, pos->die_off, &type_die))
 				continue;
 
-			if (!get_global_var_info(dloc, pos->addr, &var_name,
-						 &var_offset))
-				continue;
-
-			if (var_offset != 0)
-				continue;
+			get_global_var_info(dloc, pos->addr, &var_name, &var_offset);
 
 			global_var__add(dloc, pos->addr, var_name, &type_die);
 		}
-- 
2.52.0