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author | Michal Marek <mmarek@suse.cz> | 2011-02-04 01:57:09 +0300 |
---|---|---|
committer | Michal Marek <mmarek@suse.cz> | 2011-03-17 17:13:56 +0300 |
commit | e37ddb82500393cb417c3ab0fe0726d9a8652372 (patch) | |
tree | 6ecc94992cb5affad4fe438d9b586a61b803f928 /scripts | |
parent | 01762c4ec5f6f62c550304b9c70e824293cefdd0 (diff) | |
download | linux-e37ddb82500393cb417c3ab0fe0726d9a8652372.tar.xz |
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>
Diffstat (limited to 'scripts')
-rw-r--r-- | scripts/genksyms/genksyms.c | 71 | ||||
-rw-r--r-- | scripts/genksyms/genksyms.h | 5 | ||||
-rw-r--r-- | scripts/genksyms/lex.l | 30 | ||||
-rw-r--r-- | scripts/genksyms/parse.y | 34 |
4 files changed, 127 insertions, 13 deletions
diff --git a/scripts/genksyms/genksyms.c b/scripts/genksyms/genksyms.c index 4a350816a9e8..f9e75531ea03 100644 --- a/scripts/genksyms/genksyms.c +++ b/scripts/genksyms/genksyms.c @@ -62,6 +62,7 @@ static const struct { [SYM_ENUM] = {'e', "enum"}, [SYM_STRUCT] = {'s', "struct"}, [SYM_UNION] = {'u', "union"}, + [SYM_ENUM_CONST] = {'E', "enum constant"}, }; static int equal_list(struct string_list *a, struct string_list *b); @@ -149,10 +150,16 @@ static unsigned long crc32(const char *s) static enum symbol_type map_to_ns(enum symbol_type t) { - if (t == SYM_TYPEDEF) - t = SYM_NORMAL; - else if (t == SYM_UNION) - t = SYM_STRUCT; + switch (t) { + case SYM_ENUM_CONST: + case SYM_NORMAL: + case SYM_TYPEDEF: + return SYM_NORMAL; + case SYM_ENUM: + case SYM_STRUCT: + case SYM_UNION: + return SYM_STRUCT; + } return t; } @@ -191,10 +198,47 @@ static struct symbol *__add_symbol(const char *name, enum symbol_type type, struct string_list *defn, int is_extern, int is_reference) { - unsigned long h = crc32(name) % HASH_BUCKETS; + unsigned long h; struct symbol *sym; enum symbol_status status = STATUS_UNCHANGED; + /* The parser adds symbols in the order their declaration completes, + * so it is safe to store the value of the previous enum constant in + * a static variable. + */ + static int enum_counter; + static struct string_list *last_enum_expr; + + if (type == SYM_ENUM_CONST) { + if (defn) { + free_list(last_enum_expr, NULL); + last_enum_expr = copy_list_range(defn, NULL); + enum_counter = 1; + } else { + struct string_list *expr; + char buf[20]; + + snprintf(buf, sizeof(buf), "%d", enum_counter++); + if (last_enum_expr) { + expr = copy_list_range(last_enum_expr, NULL); + defn = concat_list(mk_node("("), + expr, + mk_node(")"), + mk_node("+"), + mk_node(buf), NULL); + } else { + defn = mk_node(buf); + } + } + } else if (type == SYM_ENUM) { + free_list(last_enum_expr, NULL); + last_enum_expr = NULL; + enum_counter = 0; + if (!name) + /* Anonymous enum definition, nothing more to do */ + return NULL; + } + h = crc32(name) % HASH_BUCKETS; for (sym = symtab[h]; sym; sym = sym->hash_next) { if (map_to_ns(sym->type) == map_to_ns(type) && strcmp(name, sym->name) == 0) { @@ -343,6 +387,22 @@ struct string_list *copy_node(struct string_list *node) return newnode; } +struct string_list *copy_list_range(struct string_list *start, + struct string_list *end) +{ + struct string_list *res, *n; + + if (start == end) + return NULL; + n = res = copy_node(start); + for (start = start->next; start != end; start = start->next) { + n->next = copy_node(start); + n = n->next; + } + n->next = NULL; + return res; +} + static int equal_list(struct string_list *a, struct string_list *b) { while (a && b) { @@ -512,6 +572,7 @@ static unsigned long expand_and_crc_sym(struct symbol *sym, unsigned long crc) crc = partial_crc32_one(' ', crc); break; + case SYM_ENUM_CONST: case SYM_TYPEDEF: subsym = find_symbol(cur->string, cur->tag, 0); /* FIXME: Bad reference files can segfault here. */ diff --git a/scripts/genksyms/genksyms.h b/scripts/genksyms/genksyms.h index 9fdafb667e76..7ec52ae3846a 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); diff --git a/scripts/genksyms/lex.l b/scripts/genksyms/lex.l index c125d06fbd36..e4ddd493fec3 100644 --- a/scripts/genksyms/lex.l +++ b/scripts/genksyms/lex.l @@ -99,12 +99,23 @@ MC_TOKEN ([~%^&*+=|<>/-]=)|(&&)|("||")|(->)|(<<)|(>>) /* Macros to append to our phrase collection list. */ +/* + * We mark any token, that that equals to a known enumerator, as + * SYM_ENUM_CONST. The parser will change this for struct and union tags later, + * the only problem is struct and union members: + * enum e { a, b }; struct s { int a, b; } + * but in this case, the only effect will be, that the ABI checksums become + * more volatile, which is acceptable. Also, such collisions are quite rare, + * so far it was only observed in include/linux/telephony.h. + */ #define _APP(T,L) do { \ cur_node = next_node; \ next_node = xmalloc(sizeof(*next_node)); \ next_node->next = cur_node; \ cur_node->string = memcpy(xmalloc(L+1), T, L+1); \ - cur_node->tag = SYM_NORMAL; \ + cur_node->tag = \ + find_symbol(cur_node->string, SYM_ENUM_CONST, 1)?\ + SYM_ENUM_CONST : SYM_NORMAL ; \ } while (0) #define APP _APP(yytext, yyleng) @@ -182,8 +193,8 @@ repeat: case STRUCT_KEYW: case UNION_KEYW: - dont_want_brace_phrase = 3; case ENUM_KEYW: + dont_want_brace_phrase = 3; suppress_type_lookup = 2; goto fini; @@ -312,7 +323,20 @@ repeat: ++count; APP; goto repeat; - case ')': case ']': case '}': + case '}': + /* is this the last line of an enum declaration? */ + if (count == 0) + { + /* Put back the token we just read so's we can find it again + after registering the expression. */ + unput(token); + + lexstate = ST_NORMAL; + token = EXPRESSION_PHRASE; + break; + } + /* FALLTHRU */ + case ')': case ']': --count; APP; goto repeat; diff --git a/scripts/genksyms/parse.y b/scripts/genksyms/parse.y index 09a265cd7193..ba5c242866c1 100644 --- a/scripts/genksyms/parse.y +++ b/scripts/genksyms/parse.y @@ -25,6 +25,7 @@ #include <assert.h> #include <stdlib.h> +#include <string.h> #include "genksyms.h" static int is_typedef; @@ -227,16 +228,19 @@ type_specifier: add_symbol(i->string, SYM_UNION, s, is_extern); $$ = $3; } - | ENUM_KEYW IDENT BRACE_PHRASE + | ENUM_KEYW IDENT enum_body { struct string_list *s = *$3, *i = *$2, *r; r = copy_node(i); r->tag = SYM_ENUM; r->next = (*$1)->next; *$3 = r; (*$1)->next = NULL; add_symbol(i->string, SYM_ENUM, s, is_extern); $$ = $3; } - - /* Anonymous s/u/e definitions. Nothing needs doing. */ - | ENUM_KEYW BRACE_PHRASE { $$ = $2; } + /* + * Anonymous enum definition. Tell add_symbol() to restart its counter. + */ + | ENUM_KEYW enum_body + { add_symbol(NULL, SYM_ENUM, NULL, 0); $$ = $2; } + /* Anonymous s/u definitions. Nothing needs doing. */ | STRUCT_KEYW class_body { $$ = $2; } | UNION_KEYW class_body { $$ = $2; } ; @@ -449,6 +453,28 @@ attribute_opt: | attribute_opt ATTRIBUTE_PHRASE ; +enum_body: + '{' enumerator_list '}' { $$ = $3; } + | '{' enumerator_list ',' '}' { $$ = $4; } + ; + +enumerator_list: + enumerator + | enumerator_list ',' enumerator + +enumerator: + IDENT + { + const char *name = strdup((*$1)->string); + add_symbol(name, SYM_ENUM_CONST, NULL, 0); + } + | IDENT '=' EXPRESSION_PHRASE + { + const char *name = strdup((*$1)->string); + struct string_list *expr = copy_list_range(*$3, *$2); + add_symbol(name, SYM_ENUM_CONST, expr, 0); + } + asm_definition: ASM_PHRASE ';' { $$ = $2; } ; |