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Subject[PATCH -tip/perf/core] perf probe: Add union member access support
From
Union members can be accessed with '.' or '->' like data structure
member access

Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Signed-off-by: Hyunchul Lee <hyc.lee@gmail.com>
---
tools/perf/util/probe-finder.c | 24 ++++++++++++++++--------
1 file changed, 16 insertions(+), 8 deletions(-)

diff --git a/tools/perf/util/probe-finder.c b/tools/perf/util/probe-finder.c
index 94a00de..cc2b856 100644
--- a/tools/perf/util/probe-finder.c
+++ b/tools/perf/util/probe-finder.c
@@ -525,8 +525,10 @@ static int convert_variable_fields(Dwarf_Die
*vr_die, const char *varname,
return -ENOENT;
}
/* Verify it is a data structure */
- if (dwarf_tag(&type) != DW_TAG_structure_type) {
- pr_warning("%s is not a data structure.\n", varname);
+ tag = dwarf_tag(&type);
+ if (tag != DW_TAG_structure_type && tag != DW_TAG_union_type) {
+ pr_warning("%s is not a data structure nor an union.\n",
+ varname);
return -EINVAL;
}

@@ -539,8 +541,9 @@ static int convert_variable_fields(Dwarf_Die
*vr_die, const char *varname,
*ref_ptr = ref;
} else {
/* Verify it is a data structure */
- if (tag != DW_TAG_structure_type) {
- pr_warning("%s is not a data structure.\n", varname);
+ if (tag != DW_TAG_structure_type && tag != DW_TAG_union_type) {
+ pr_warning("%s is not a data structure nor an union.\n",
+ varname);
return -EINVAL;
}
if (field->name[0] == '[') {
@@ -567,10 +570,15 @@ static int convert_variable_fields(Dwarf_Die
*vr_die, const char *varname,
}

/* Get the offset of the field */
- ret = die_get_data_member_location(die_mem, &offs);
- if (ret < 0) {
- pr_warning("Failed to get the offset of %s.\n", field->name);
- return ret;
+ if (tag == DW_TAG_union_type) {
+ offs = 0;
+ } else {
+ ret = die_get_data_member_location(die_mem, &offs);
+ if (ret < 0) {
+ pr_warning("Failed to get the offset of %s.\n",
+ field->name);
+ return ret;
+ }
}
ref->offset += (long)offs;

--
1.7.10

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