[RFC 22/31] objtool: Make find_symbol_containing() less arbitrary

[Josh Poimboeuf]

In the rare case of overlapping symbols, find_symbol_containing() just
returns the first one it finds.  Make it less arbitrary by returning the
smallest symbol with size > 0.

Eventually we should consider making such overlapping symbols illegal.

Signed-off-by: Josh Poimboeuf <jpoimboe@xxxxxxxxxx>
---
 tools/objtool/elf.c | 25 ++++++++++++++++++++-----
 1 file changed, 20 insertions(+), 5 deletions(-)

diff --git a/tools/objtool/elf.c b/tools/objtool/elf.c
index 7f89b0a99886..49528e7835aa 100644
--- a/tools/objtool/elf.c
+++ b/tools/objtool/elf.c
@@ -195,14 +195,29 @@ struct symbol *find_func_by_offset(struct section *sec, unsigned long offset)
 struct symbol *find_symbol_containing(const struct section *sec, unsigned long offset)
 {
 	struct rb_root_cached *tree = (struct rb_root_cached *)&sec->symbol_tree;
-	struct symbol *iter;
+	struct symbol *sym = NULL, *tmp;
 
-	__sym_for_each(iter, tree, offset, offset) {
-		if (iter->type != STT_SECTION)
-			return iter;
+	__sym_for_each(tmp, tree, offset, offset) {
+		if (tmp->len) {
+			if (!sym) {
+				sym = tmp;
+				continue;
+			}
+
+			if (sym->offset != tmp->offset || sym->len != tmp->len) {
+				/*
+				 * In the rare case of overlapping symbols,
+				 * pick the smaller one.
+				 *
+				 * TODO: outlaw overlapping symbols
+				 */
+				if (tmp->len < sym->len)
+					sym = tmp;
+			}
+		}
 	}
 
-	return NULL;
+	return sym;
 }
 
 /*
-- 
2.45.2