perf annotate-data: Fix libdw API contract violations

Check return values of `dwarf_aggregate_size` and `dwarf_formudata`.

Additionally:
 - Avoid `vfprintf` undefined behavior with `NULL` strings by using
   the `die_name()` helper for `dwarf_diename()` in `pr_*` calls.
 - Use `die_get_data_member_location()` (updated to use
   `dwarf_attr_integrate`) to correctly parse location expressions
   for inherited member locations in the fallback path when
   `dwarf_formudata()` fails.

Fixes: 2bc3cf575a162a2c ("perf annotate-data: Improve debug message with location info")
Fixes: 4a111cadac85362e ("perf annotate-data: Add member field in the data type")
Fixes: 8b1042c425f6a5a9 ("perf annotate-data: Set bitfield member offset and size properly")
Fixes: fc044c53b99fad03 ("perf annotate-data: Add dso->data_types tree")
Assisted-by: Gemini-CLI:Google Gemini 3
Signed-off-by: Ian Rogers <irogers@google.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: James Clark <james.clark@linaro.org>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Zecheng Li <zli94@ncsu.edu>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

diff --git a/tools/perf/util/annotate-data.c b/tools/perf/util/annotate-data.c
index 1eff0a27237d940925dc6c48b61e294c52d16520..63e3c54fab421f659225e0293a2b78170d3f4579 100644 (file)
--- a/tools/perf/util/annotate-data.c
+++ b/tools/perf/util/annotate-data.c
@@ -74,7 +74,8 @@ void pr_debug_type_name(Dwarf_Die *die, enum type_state_kind kind)
                break;
        }
 
-       dwarf_aggregate_size(die, &size);
+       if (dwarf_aggregate_size(die, &size) != 0)
+               size = 0;
 
        strbuf_init(&sb, 32);
        die_get_typename_from_type(die, &sb);
@@ -146,9 +147,9 @@ static void pr_debug_scope(Dwarf_Die *scope_die)
 
        tag = dwarf_tag(scope_die);
        if (tag == DW_TAG_subprogram)
-               pr_info("[function] %s\n", dwarf_diename(scope_die));
+               pr_info("[function] %s\n", die_name(scope_die));
        else if (tag == DW_TAG_inlined_subroutine)
-               pr_info("[inlined] %s\n", dwarf_diename(scope_die));
+               pr_info("[inlined] %s\n", die_name(scope_die));
        else if (tag == DW_TAG_lexical_block)
                pr_info("[block]\n");
        else
@@ -250,9 +251,12 @@ static int __add_member_cb(Dwarf_Die *die, void *arg)
        if (dwarf_aggregate_size(&die_mem, &size) < 0)
                size = 0;
 
-       if (dwarf_attr_integrate(die, DW_AT_data_member_location, &attr))
-               dwarf_formudata(&attr, &loc);
-       else {
+       if (dwarf_attr_integrate(die, DW_AT_data_member_location, &attr)) {
+               if (dwarf_formudata(&attr, &loc) != 0) {
+                       if (die_get_data_member_location(die, &loc) != 0)
+                               loc = 0;
+               }
+       } else {
                /* bitfield member */
                if (dwarf_attr_integrate(die, DW_AT_data_bit_offset, &attr) &&
                    dwarf_formudata(&attr, &loc) == 0)
@@ -273,7 +277,9 @@ static int __add_member_cb(Dwarf_Die *die, void *arg)
                                     dwarf_diename(die), (long)bit_size) < 0)
                                member->var_name = NULL;
                } else {
-                       member->var_name = strdup(dwarf_diename(die));
+                       const char *name = dwarf_diename(die);
+
+                       member->var_name = name ? strdup(name) : NULL;
                }
 
                if (member->var_name == NULL) {
@@ -370,7 +376,8 @@ static struct annotated_data_type *dso__findnew_data_type(struct dso *dso,
        if (dwarf_tag(type_die) == DW_TAG_typedef)
                die_get_real_type(type_die, type_die);
 
-       dwarf_aggregate_size(type_die, &size);
+       if (dwarf_aggregate_size(type_die, &size) != 0)
+               size = 0;
 
        /* Check existing nodes in dso->data_types tree */
        key.self.type_name = type_name;
@@ -1569,7 +1576,7 @@ static int find_data_type_die(struct data_loc_info *dloc, Dwarf_Die *type_die)
        offset = loc->offset;
 
        pr_debug_dtp("CU for %s (die:%#lx)\n",
-                    dwarf_diename(&cu_die), (long)dwarf_dieoffset(&cu_die));
+                    die_name(&cu_die), (long)dwarf_dieoffset(&cu_die));
 
        if (reg == DWARF_REG_PC) {
                if (get_global_var_type(&cu_die, dloc, dloc->ip, dloc->var_addr,
@@ -1636,7 +1643,7 @@ retry:
                }
 
                pr_debug_dtp("found \"%s\" (die: %#lx) in scope=%d/%d (die: %#lx) ",
-                            dwarf_diename(&var_die), (long)dwarf_dieoffset(&var_die),
+                            die_name(&var_die), (long)dwarf_dieoffset(&var_die),
                             i+1, nr_scopes, (long)dwarf_dieoffset(&scopes[i]));
 
                if (reg == DWARF_REG_PC) {