Example
#strong_define FOO 1
#undef FOO // silently ignored
#define FOO 2 // silently ignored
This allows (for example) to override CONFIG_XXX values without
editing include/linux/autoconf.h
Signed-off-by: Oleg Nesterov <oleg@xxxxxxxxxx>
--- git-snapshot-20060904/symbol.h~6DEF 2006-09-04 19:44:19.000000000 +0400
+++ git-snapshot-20060904/symbol.h 2006-09-04 19:48:23.000000000 +0400
@@ -80,13 +80,14 @@ struct symbol_op {
extern int expand_safe_p(struct expression *expr, int cost);
extern int expand_constant_p(struct expression *expr, int cost);
-#define SYM_ATTR_WEAK 1
-#define SYM_ATTR_NORMAL 0
+#define SYM_ATTR_WEAK 0
+#define SYM_ATTR_NORMAL 1
+#define SYM_ATTR_STRONG 2
struct symbol {
enum namespace namespace:8;
enum type type:8;
- unsigned char used:1, attr:1;
+ unsigned char used:1, attr:2;
struct position pos; /* Where this symbol was declared */
struct ident *ident; /* What identifier this symbol is associated with */
struct symbol *next_id; /* Next semantic symbol that shares this identifier */
--- git-snapshot-20060904/pre-process.c~6DEF 2006-09-04 19:44:19.000000000 +0400
+++ git-snapshot-20060904/pre-process.c 2006-09-04 19:48:23.000000000 +0400
@@ -1088,7 +1088,7 @@ static int do_handle_define(struct strea
if (sym) {
int clean;
- if (attr > sym->attr)
+ if (attr < sym->attr)
goto out;
clean = (attr == sym->attr);
@@ -1134,6 +1134,11 @@ static int handle_weak_define(struct str
return do_handle_define(stream, line, token, SYM_ATTR_WEAK);
}
+static int handle_strong_define(struct stream *stream, struct token **line, struct token *token)
+{
+ return do_handle_define(stream, line, token, SYM_ATTR_STRONG);
+}
+
static int handle_undef(struct stream *stream, struct token **line, struct token *token)
{
struct token *left = token->next;
@@ -1145,7 +1150,7 @@ static int handle_undef(struct stream *s
}
sym = lookup_macro(left->ident);
- if (!sym)
+ if (!sym || sym->attr > SYM_ATTR_NORMAL)
return 1;
if (sym->scope != file_scope) {
@@ -1565,15 +1570,16 @@ static void init_preprocessor(void)
const char *name;
int (*handler)(struct stream *, struct token **, struct token *);
} normal[] = {
- { "define", handle_define },
- { "weak_define",handle_weak_define },
- { "undef", handle_undef },
- { "warning", handle_warning },
- { "error", handle_error },
- { "include", handle_include },
- { "include_next",handle_include_next },
- { "pragma", handle_pragma },
- { "line", handle_line },
+ { "define", handle_define },
+ { "weak_define", handle_weak_define },
+ { "strong_define", handle_strong_define },
+ { "undef", handle_undef },
+ { "warning", handle_warning },
+ { "error", handle_error },
+ { "include", handle_include },
+ { "include_next", handle_include_next },
+ { "pragma", handle_pragma },
+ { "line", handle_line },
// our internal preprocessor tokens
{ "nostdinc", handle_nostdinc },
--
VGER BF report: H 5.71153e-14
-
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