perf annotate-data: Handle array style accesses

On x86, instructions for array access often looks like below.

  mov  0x1234(%rax,%rbx,8), %rcx

Usually the first register holds the type information and the second one
has the index.  And the current code only looks up a variable for the
first register.  But it's possible to be in the other way around so it
needs to check the second register if the first one failed.

The stat changed like this.

  Annotate data type stats:
  total 294, ok 148 (50.3%), bad 146 (49.7%)
  -----------------------------------------------------------
          30 : no_sym
          32 : no_mem_ops
          66 : no_var
          10 : no_typeinfo
           8 : bad_offset

Reviewed-by: Ian Rogers <irogers@google.com>
Cc: Stephane Eranian <eranian@google.com>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Link: https://lore.kernel.org/r/20240117062657.985479-4-namhyung@kernel.org
Signed-off-by: Namhyung Kim <namhyung@kernel.org>

1 files changed, 18 insertions, 6 deletions

diff --git a/tools/perf/util/annotate-data.c b/tools/perf/util/annotate-data.c
index f22b4f18271c..d1ceac7e2441 100644
--- a/tools/perf/util/annotate-data.c
+++ b/tools/perf/util/annotate-data.c
@@ -9,6 +9,7 @@
 #include <stdlib.h>
 #include <inttypes.h>
 
+#include "annotate.h"
 #include "annotate-data.h"
 #include "debuginfo.h"
 #include "debug.h"
@@ -207,7 +208,8 @@ static int check_variable(Dwarf_Die *var_die, Dwarf_Die *type_die, int offset)
 	 * It expects a pointer type for a memory access.
 	 * Convert to a real type it points to.
 	 */
-	if (dwarf_tag(type_die) != DW_TAG_pointer_type ||
+	if ((dwarf_tag(type_die) != DW_TAG_pointer_type &&
+	     dwarf_tag(type_die) != DW_TAG_array_type) ||
 	    die_get_real_type(type_die, type_die) == NULL) {
 		pr_debug("no pointer or no type\n");
 		ann_data_stat.no_typeinfo++;
@@ -233,10 +235,11 @@ static int check_variable(Dwarf_Die *var_die, Dwarf_Die *type_die, int offset)
 
 /* The result will be saved in @type_die */
 static int find_data_type_die(struct debuginfo *di, u64 pc,
-			      int reg, int offset, Dwarf_Die *type_die)
+			      struct annotated_op_loc *loc, Dwarf_Die *type_die)
 {
 	Dwarf_Die cu_die, var_die;
 	Dwarf_Die *scopes = NULL;
+	int reg, offset;
 	int ret = -1;
 	int i, nr_scopes;
 
@@ -250,6 +253,10 @@ static int find_data_type_die(struct debuginfo *di, u64 pc,
 	/* Get a list of nested scopes - i.e. (inlined) functions and blocks. */
 	nr_scopes = die_get_scopes(&cu_die, pc, &scopes);
 
+	reg = loc->reg1;
+	offset = loc->offset;
+
+retry:
 	/* Search from the inner-most scope to the outer */
 	for (i = nr_scopes - 1; i >= 0; i--) {
 		/* Look up variables/parameters in this scope */
@@ -260,6 +267,12 @@ static int find_data_type_die(struct debuginfo *di, u64 pc,
 		ret = check_variable(&var_die, type_die, offset);
 		goto out;
 	}
+
+	if (loc->multi_regs && reg == loc->reg1 && loc->reg1 != loc->reg2) {
+		reg = loc->reg2;
+		goto retry;
+	}
+
 	if (ret < 0)
 		ann_data_stat.no_var++;
 
@@ -272,15 +285,14 @@ out:
  * find_data_type - Return a data type at the location
  * @ms: map and symbol at the location
  * @ip: instruction address of the memory access
- * @reg: register that holds the base address
- * @offset: offset from the base address
+ * @loc: instruction operand location
  *
  * This functions searches the debug information of the binary to get the data
  * type it accesses.  The exact location is expressed by (ip, reg, offset).
  * It return %NULL if not found.
  */
 struct annotated_data_type *find_data_type(struct map_symbol *ms, u64 ip,
-					   int reg, int offset)
+					   struct annotated_op_loc *loc)
 {
 	struct annotated_data_type *result = NULL;
 	struct dso *dso = map__dso(ms->map);
@@ -300,7 +312,7 @@ struct annotated_data_type *find_data_type(struct map_symbol *ms, u64 ip,
 	 * a file address for DWARF processing.
 	 */
 	pc = map__rip_2objdump(ms->map, ip);
-	if (find_data_type_die(di, pc, reg, offset, &type_die) < 0)
+	if (find_data_type_die(di, pc, loc, &type_die) < 0)
 		goto out;
 
 	result = dso__findnew_data_type(dso, &type_die);