perf annotate-data: Add find_data_type() to get type from memory access

The find_data_type() is to get a data type from the memory access at the
given address (IP) using a register and an offset.

It requires DWARF debug info in the DSO and searches the list of
variables and function parameters in the scope.

In a pseudo code, it does basically the following:

  find_data_type(dso, ip, reg, offset)
  {
      pc = map__rip_2objdump(ip);
      CU = dwarf_addrdie(dso->dwarf, pc);
      scopes = die_get_scopes(CU, pc);
      for_each_scope(S, scopes) {
          V = die_find_variable_by_reg(S, pc, reg);
          if (V && V.type == pointer_type) {
              T = die_get_real_type(V);
              if (offset < T.size)
                  return T;
          }
      }
      return NULL;
  }

Committer notes:

The 'size' variable in check_variable() is 64-bit, so use PRIu64 and
inttypes.h to debug it.

Ditto at find_data_type_die().

Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Ian Rogers <irogers@google.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: linux-toolchains@vger.kernel.org
Cc: linux-trace-devel@vger.kernel.org
Link: https://lore.kernel.org/r/20231213001323.718046-4-namhyung@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

1 files changed, 40 insertions, 0 deletions

diff --git a/tools/perf/util/annotate-data.h b/tools/perf/util/annotate-data.h
new file mode 100644
index 000000000000..633147f78ca5
--- /dev/null
+++ b/tools/perf/util/annotate-data.h
@@ -0,0 +1,40 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _PERF_ANNOTATE_DATA_H
+#define _PERF_ANNOTATE_DATA_H
+
+#include <errno.h>
+#include <linux/compiler.h>
+#include <linux/types.h>
+
+struct map_symbol;
+
+/**
+ * struct annotated_data_type - Data type to profile
+ * @type_name: Name of the data type
+ * @type_size: Size of the data type
+ *
+ * This represents a data type accessed by samples in the profile data.
+ */
+struct annotated_data_type {
+	char *type_name;
+	int type_size;
+};
+
+#ifdef HAVE_DWARF_SUPPORT
+
+/* Returns data type at the location (ip, reg, offset) */
+struct annotated_data_type *find_data_type(struct map_symbol *ms, u64 ip,
+					   int reg, int offset);
+
+#else /* HAVE_DWARF_SUPPORT */
+
+static inline struct annotated_data_type *
+find_data_type(struct map_symbol *ms __maybe_unused, u64 ip __maybe_unused,
+	       int reg __maybe_unused, int offset __maybe_unused)
+{
+	return NULL;
+}
+
+#endif /* HAVE_DWARF_SUPPORT */
+
+#endif /* _PERF_ANNOTATE_DATA_H */