perf symbols: Record whether a dso is 64-bit

Add a flag to 'struct dso' to record if the dso is 64-bit or not.
Update the flag when reading the ELF.

This is needed for instruction decoding.  For example, x86 instruction
decoding depends on whether or not the 64-bit instruction set is used.

Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Namhyung Kim <namhyung@gmail.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Link: http://lkml.kernel.org/r/1405332185-4050-18-git-send-email-adrian.hunter@intel.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
diff --git a/tools/perf/util/symbol-elf.c b/tools/perf/util/symbol-elf.c
index dce5ccf..cef8f42 100644
--- a/tools/perf/util/symbol-elf.c
+++ b/tools/perf/util/symbol-elf.c
@@ -599,6 +599,8 @@
 			goto out_elf_end;
 	}
 
+	ss->is_64_bit = (gelf_getclass(elf) == ELFCLASS64);
+
 	ss->symtab = elf_section_by_name(elf, &ehdr, &ss->symshdr, ".symtab",
 			NULL);
 	if (ss->symshdr.sh_type != SHT_SYMTAB)
@@ -699,6 +701,7 @@
 	bool remap_kernel = false, adjust_kernel_syms = false;
 
 	dso->symtab_type = syms_ss->type;
+	dso->is_64_bit = syms_ss->is_64_bit;
 	dso->rel = syms_ss->ehdr.e_type == ET_REL;
 
 	/*