[PATCH v3 7/8] objtool/klp: Correlate locals to globals

[Song Liu <song@kernel.org>]

Allow correlating original locals to patched globals, and vice versa.
This is needed when:

1. User adds/removes "static" for a function.
2. CONFIG_LTO_CLANG_THIN promotes local functions and objects to global
   and add .llvm.<hash> suffix.

Given this is a less common scenario, show warnings when this is needed.

Signed-off-by: Song Liu <song@kernel.org>
---
 tools/objtool/klp-diff.c | 34 ++++++++++++++++++++++++++++++++++
 1 file changed, 34 insertions(+)

diff --git a/tools/objtool/klp-diff.c b/tools/objtool/klp-diff.c
index 92043da0ed0b..5cda965807a5 100644
--- a/tools/objtool/klp-diff.c
+++ b/tools/objtool/klp-diff.c
@@ -517,6 +517,40 @@ static int correlate_symbols(struct elfs *e)
 		}
 	}
 
+	/* Correlate original locals with patched globals */
+	for_each_sym(e->orig, sym1) {
+		if (sym1->twin || dont_correlate(sym1) || !is_local_sym(sym1))
+			continue;
+
+		sym2 = find_global_symbol_by_name(e->patched, sym1->name);
+		if (!sym2 && find_global_symbol_by_demangled_name(e->patched, sym1, &sym2))
+			return -1;
+
+		if (sym2 && !sym2->twin) {
+			sym1->twin = sym2;
+			sym2->twin = sym1;
+			WARN("correlate LOCAL %s (original) to GLOBAL %s (patched)",
+			     sym1->name, sym2->name);
+		}
+	}
+
+	/* Correlate original globals with patched locals */
+	for_each_sym(e->patched, sym2) {
+		if (sym2->twin || dont_correlate(sym2) || !is_local_sym(sym2))
+			continue;
+
+		sym1 = find_global_symbol_by_name(e->orig, sym2->name);
+		if (!sym1 && find_global_symbol_by_demangled_name(e->orig, sym2, &sym1))
+			return -1;
+
+		if (sym1 && !sym1->twin) {
+			sym2->twin = sym1;
+			sym1->twin = sym2;
+			WARN("correlate GLOBAL %s (origial) to LOCAL %s (patched)",
+			     sym1->name, sym2->name);
+		}
+	}
+
 	for_each_sym(e->orig, sym1) {
 		if (sym1->twin || dont_correlate(sym1))
 			continue;
-- 
2.47.3