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

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Message-ID: <20260127020617.2804780-7-zli94@ncsu.edu>
Date: Mon, 26 Jan 2026 21:04:59 -0500
From: Zecheng Li <zli94@...u.edu>
To: Peter Zijlstra <peterz@...radead.org>,
	Ingo Molnar <mingo@...hat.com>,
	Arnaldo Carvalho de Melo <acme@...nel.org>,
	Namhyung Kim <namhyung@...nel.org>
Cc: Mark Rutland <mark.rutland@....com>,
	Alexander Shishkin <alexander.shishkin@...ux.intel.com>,
	Jiri Olsa <jolsa@...nel.org>,
	Ian Rogers <irogers@...gle.com>,
	Adrian Hunter <adrian.hunter@...el.com>,
	James Clark <james.clark@...aro.org>,
	Zecheng Li <zli94@...u.edu>,
	xliuprof@...gle.com,
	linux-perf-users@...r.kernel.org,
	linux-kernel@...r.kernel.org
Subject: [PATCH v1 06/11] perf annotate-data: Collect global variables without name

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@...u.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