perf annotate-data: Support global variables

Global variables are accessed using PC-relative address so it needs to
be handled separately.  The PC-rel addressing is detected by using
DWARF_REG_PC.  On x86, %rip register would be used.

The address can be calculated using the ip and offset in the
instruction.  But it should start from the next instruction so add
calculate_pcrel_addr() to do it properly.

But global variables defined in a different file would only have a
declaration which doesn't include a location list.  So it first tries
to get the type info using the address, and then looks up the variable
declarations using name.  The name of global variables should be get
from the symbol table.  The declaration would have the type info.

So extend find_var_type() to take both address and name for global
variables.

The stat is now looks like:

  Annotate data type stats:
  total 294, ok 153 (52.0%), bad 141 (48.0%)
  -----------------------------------------------------------
          30 : no_sym
          32 : no_mem_ops
          61 : 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/20240117062657.985479-7-namhyung@kernel.org
Signed-off-by: Namhyung Kim <namhyung@kernel.org>

1 files changed, 4 insertions, 2 deletions

diff --git a/tools/perf/util/annotate-data.h b/tools/perf/util/annotate-data.h
index 214c625e7bc9..1b0db8e8c40e 100644
--- a/tools/perf/util/annotate-data.h
+++ b/tools/perf/util/annotate-data.h
@@ -107,7 +107,8 @@ extern struct annotated_data_stat ann_data_stat;
 
 /* Returns data type at the location (ip, reg, offset) */
 struct annotated_data_type *find_data_type(struct map_symbol *ms, u64 ip,
-					   struct annotated_op_loc *loc);
+					   struct annotated_op_loc *loc, u64 addr,
+					   const char *var_name);
 
 /* Update type access histogram at the given offset */
 int annotated_data_type__update_samples(struct annotated_data_type *adt,
@@ -121,7 +122,8 @@ void annotated_data_type__tree_delete(struct rb_root *root);
 
 static inline struct annotated_data_type *
 find_data_type(struct map_symbol *ms __maybe_unused, u64 ip __maybe_unused,
-	       struct annotated_op_loc *loc __maybe_unused)
+	       struct annotated_op_loc *loc __maybe_unused,
+	       u64 addr __maybe_unused, const char *var_name __maybe_unused)
 {
 	return NULL;
 }