genksyms: Track changes to enum constants

Enum constants can be used as array sizes; if the enum itself does not
appear in the symbol expansion, a change in the enum constant will go
unnoticed. Example patch that changes the ABI but does not change the
checksum with current genksyms:

| enum e {
|	E1,
|	E2,
|+	E3,
|	E_MAX
| };
|
| struct s {
|	int a[E_MAX];
| }
|
| int f(struct s *s) { ... }
| EXPORT_SYMBOL(f)

Therefore, remember the value of each enum constant and
expand each occurence to <constant> <value>. The value is not actually
computed, but instead an expression in the form
(last explicitly assigned value) + N
is used. This avoids having to parse and semantically understand whole
of C.

Note: The changes won't take effect until the lexer and parser are
rebuilt by the next patch.

Signed-off-by: Michal Marek <mmarek@suse.cz>
Acked-by: Sam Ravnborg <sam@ravnborg.org>

1 files changed, 4 insertions, 1 deletions

diff --git a/scripts/genksyms/genksyms.h b/scripts/genksyms/genksyms.h
index 9fdafb667e7..7ec52ae3846 100644
--- a/scripts/genksyms/genksyms.h
+++ b/scripts/genksyms/genksyms.h
@@ -26,7 +26,8 @@
 #include <stdio.h>
 
 enum symbol_type {
-	SYM_NORMAL, SYM_TYPEDEF, SYM_ENUM, SYM_STRUCT, SYM_UNION
+	SYM_NORMAL, SYM_TYPEDEF, SYM_ENUM, SYM_STRUCT, SYM_UNION,
+	SYM_ENUM_CONST
 };
 
 enum symbol_status {
@@ -66,6 +67,8 @@ void export_symbol(const char *);
 void free_node(struct string_list *list);
 void free_list(struct string_list *s, struct string_list *e);
 struct string_list *copy_node(struct string_list *);
+struct string_list *copy_list_range(struct string_list *start,
+				    struct string_list *end);
 
 int yylex(void);
 int yyparse(void);