objtool/klp: Fix is_uncorrelated_static_local() for Clang

For naming function-local static locals, GCC uses <var>.<id>, e.g.
__already_done.15, while Clang uses <func>.<var> with optional .<id>,
e.g. create_worker.__already_done.111

The existing is_uncorrelated_static_local() check only matches the GCC
convention where the variable name is a prefix.  Handle both cases by
checking for a prefix match (GCC) and by checking after the first dot
separator (Clang).

Fixes: dd590d4d57eb ("objtool/klp: Introduce klp diff subcommand for diffing object files")
Signed-off-by: Joe Lawrence <joe.lawrence@redhat.com>
Acked-by: Song Liu <song@kernel.org>
Reviewed-by: Miroslav Benes <mbenes@suse.cz>
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>

diff --git a/tools/objtool/klp-diff.c b/tools/objtool/klp-diff.c
index 0b0d1503851ff9cdc5c03bf7b88e86f66a085724..b1b068e9b4c7088d19e121576800b3ac19dfc21e 100644 (file)
--- a/tools/objtool/klp-diff.c
+++ b/tools/objtool/klp-diff.c
@@ -242,16 +242,17 @@ static struct symbol *next_file_symbol(struct elf *elf, struct symbol *sym)
 static bool is_uncorrelated_static_local(struct symbol *sym)
 {
        static const char * const vars[] = {
-               "__already_done.",
-               "__func__.",
-               "__key.",
-               "__warned.",
-               "_entry.",
-               "_entry_ptr.",
-               "_rs.",
-               "descriptor.",
-               "CSWTCH.",
+               "__already_done",
+               "__func__",
+               "__key",
+               "__warned",
+               "_entry",
+               "_entry_ptr",
+               "_rs",
+               "descriptor",
+               "CSWTCH",
        };
+       const char *dot;
 
        if (!is_object_sym(sym) || !is_local_sym(sym))
                return false;
@@ -259,8 +260,20 @@ static bool is_uncorrelated_static_local(struct symbol *sym)
        if (!strcmp(sym->sec->name, ".data.once"))
                return true;
 
+       dot = strchr(sym->name, '.');
+       if (!dot)
+               return false;
+
        for (int i = 0; i < ARRAY_SIZE(vars); i++) {
-               if (strstarts(sym->name, vars[i]))
+               size_t len = strlen(vars[i]);
+
+               /* GCC: <var>.<id> */
+               if (strstarts(sym->name, vars[i]) && (sym->name[len] == '.'))
+                       return true;
+
+               /* Clang: <func>.<var>[.<id>] */
+               if (strstarts(dot + 1, vars[i]) &&
+                   (dot[1 + len] == '.' || dot[1 + len] == '\0'))
                        return true;
        }