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genksyms: Track changes to enum constants

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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>
This commit is contained in:
Michal Marek
2011-02-03 23:57:09 +01:00
parent 01762c4ec5
commit e37ddb8250
4 changed files with 127 additions and 13 deletions
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34
scripts/genksyms/parse.y
View File

@@ -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; }
;