objtool: Optimize find_section_by_index()
In order to avoid a linear search (over 20k entries), add an
section_hash to the elf object.
This reduces objtool on vmlinux.o from a few minutes to around 45
seconds.
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Miroslav Benes <mbenes@suse.cz>
Acked-by: Josh Poimboeuf <jpoimboe@redhat.com>
Link: https://lkml.kernel.org/r/20200324160924.381249993@infradead.org
diff --git a/tools/objtool/elf.h b/tools/objtool/elf.h
index 1222980..8c272eb 100644
--- a/tools/objtool/elf.h
+++ b/tools/objtool/elf.h
@@ -25,6 +25,7 @@
struct section {
struct list_head list;
+ struct hlist_node hash;
GElf_Shdr sh;
struct list_head symbol_list;
struct list_head rela_list;
@@ -71,6 +72,7 @@ struct elf {
char *name;
struct list_head sections;
DECLARE_HASHTABLE(symbol_hash, 20);
+ DECLARE_HASHTABLE(section_hash, 16);
};