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bianbu-linux-6.6/scripts/kconfig/expr.c
Martin Walch e911503085 Kconfig: Remove bad inference rules expr_eliminate_dups2() 
expr_eliminate_dups2() in scripts/kconfig/expr.c applies two invalid
inference rules:

(FOO || BAR) && (!FOO && !BAR) -> n
(FOO && BAR) || (!FOO || !BAR) -> y

They would be correct in propositional logic, but this is a three-valued
logic, and here it is wrong in that it changes semantics. It becomes
immediately visible when assigning the value 1 to both, FOO and BAR:

(FOO || BAR) && (!FOO && !BAR)
-> min(max(1, 1), min(2-1, 2-1)) = min(1, 1) = 1

while n evaluates to 0 and

(FOO && BAR) || (!FOO || !BAR)
-> max(min(1, 1), max(2-1, 2-1)) = max(1, 1) = 1

with y evaluating to 2.

Fix it by removing expr_eliminate_dups2() and the functions that have no
use anywhere else: expr_extract_eq_and(), expr_extract_eq_or(),
and expr_extract_eq() from scripts/kconfig/expr.c

Currently the bug is not triggered in mainline, so this patch does not
modify the configuration space there. To observe the bug consider this
example:

config MODULES
        def_bool y
        option modules

config FOO
        def_tristate m

config BAR
        def_tristate m

config TEST1
        def_tristate y
        depends on (FOO || BAR) && (!FOO && !BAR)

if TEST1 = n
comment "TEST1 broken"
endif

config TEST2
        def_tristate y
        depends on (FOO && BAR) || (!FOO || !BAR)

if TEST2 = y
comment "TEST2 broken"
endif

config TEST3
        def_tristate y
        depends on m && !m

if TEST3 = n
comment "TEST3 broken"
endif

TEST1, TEST2 and TEST3 should all evaluate to m, but without the patch,
none of them does. It is probably not obvious that TEST3 is the same bug,
but it becomes clear when considering what happens internally to the
expression
m && !m":
First it expands to
(m && MODULES) && !(m && MODULES),
then it is transformed into
(m && MODULES) && (!m || !MODULES),
and finally due to the bug it is replaced with n.

As a side effect, this patch reduces code size in expr.c by roughly 10%
and slightly improves startup time for all configuration frontends.

Signed-off-by: Martin Walch <walch.martin@web.de>
Signed-off-by: Michal Marek <mmarek@suse.cz>
2015-05-25 16:04:12 +08:00

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/*
* Copyright (C) 2002 Roman Zippel <zippel@linux-m68k.org>
* Released under the terms of the GNU GPL v2.0.
*/
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include "lkc.h"
#define DEBUG_EXPR 0
static int expr_eq(struct expr *e1, struct expr *e2);
static struct expr *expr_eliminate_yn(struct expr *e);
struct expr *expr_alloc_symbol(struct symbol *sym)
{
struct expr *e = xcalloc(1, sizeof(*e));
e->type = E_SYMBOL;
e->left.sym = sym;
return e;
}
struct expr *expr_alloc_one(enum expr_type type, struct expr *ce)
{
struct expr *e = xcalloc(1, sizeof(*e));
e->type = type;
e->left.expr = ce;
return e;
}
struct expr *expr_alloc_two(enum expr_type type, struct expr *e1, struct expr *e2)
{
struct expr *e = xcalloc(1, sizeof(*e));
e->type = type;
e->left.expr = e1;
e->right.expr = e2;
return e;
}
struct expr *expr_alloc_comp(enum expr_type type, struct symbol *s1, struct symbol *s2)
{
struct expr *e = xcalloc(1, sizeof(*e));
e->type = type;
e->left.sym = s1;
e->right.sym = s2;
return e;
}
struct expr *expr_alloc_and(struct expr *e1, struct expr *e2)
{
if (!e1)
return e2;
return e2 ? expr_alloc_two(E_AND, e1, e2) : e1;
}
struct expr *expr_alloc_or(struct expr *e1, struct expr *e2)
{
if (!e1)
return e2;
return e2 ? expr_alloc_two(E_OR, e1, e2) : e1;
}
struct expr *expr_copy(const struct expr *org)
{
struct expr *e;
if (!org)
return NULL;
e = xmalloc(sizeof(*org));
memcpy(e, org, sizeof(*org));
switch (org->type) {
case E_SYMBOL:
e->left = org->left;
break;
case E_NOT:
e->left.expr = expr_copy(org->left.expr);
break;
case E_EQUAL:
case E_UNEQUAL:
e->left.sym = org->left.sym;
e->right.sym = org->right.sym;
break;
case E_AND:
case E_OR:
case E_LIST:
e->left.expr = expr_copy(org->left.expr);
e->right.expr = expr_copy(org->right.expr);
break;
default:
printf("can't copy type %d\n", e->type);
free(e);
e = NULL;
break;
}
return e;
}
void expr_free(struct expr *e)
{
if (!e)
return;
switch (e->type) {
case E_SYMBOL:
break;
case E_NOT:
expr_free(e->left.expr);
return;
case E_EQUAL:
case E_UNEQUAL:
break;
case E_OR:
case E_AND:
expr_free(e->left.expr);
expr_free(e->right.expr);
break;
default:
printf("how to free type %d?\n", e->type);
break;
}
free(e);
}
static int trans_count;
#define e1 (*ep1)
#define e2 (*ep2)
static void __expr_eliminate_eq(enum expr_type type, struct expr **ep1, struct expr **ep2)
{
if (e1->type == type) {
__expr_eliminate_eq(type, &e1->left.expr, &e2);
__expr_eliminate_eq(type, &e1->right.expr, &e2);
return;
}
if (e2->type == type) {
__expr_eliminate_eq(type, &e1, &e2->left.expr);
__expr_eliminate_eq(type, &e1, &e2->right.expr);
return;
}
if (e1->type == E_SYMBOL && e2->type == E_SYMBOL &&
e1->left.sym == e2->left.sym &&
(e1->left.sym == &symbol_yes || e1->left.sym == &symbol_no))
return;
if (!expr_eq(e1, e2))
return;
trans_count++;
expr_free(e1); expr_free(e2);
switch (type) {
case E_OR:
e1 = expr_alloc_symbol(&symbol_no);
e2 = expr_alloc_symbol(&symbol_no);
break;
case E_AND:
e1 = expr_alloc_symbol(&symbol_yes);
e2 = expr_alloc_symbol(&symbol_yes);
break;
default:
;
}
}
void expr_eliminate_eq(struct expr **ep1, struct expr **ep2)
{
if (!e1 || !e2)
return;
switch (e1->type) {
case E_OR:
case E_AND:
__expr_eliminate_eq(e1->type, ep1, ep2);
default:
;
}
if (e1->type != e2->type) switch (e2->type) {
case E_OR:
case E_AND:
__expr_eliminate_eq(e2->type, ep1, ep2);
default:
;
}
e1 = expr_eliminate_yn(e1);
e2 = expr_eliminate_yn(e2);
}
#undef e1
#undef e2
static int expr_eq(struct expr *e1, struct expr *e2)
{
int res, old_count;
if (e1->type != e2->type)
return 0;
switch (e1->type) {
case E_EQUAL:
case E_UNEQUAL:
return e1->left.sym == e2->left.sym && e1->right.sym == e2->right.sym;
case E_SYMBOL:
return e1->left.sym == e2->left.sym;
case E_NOT:
return expr_eq(e1->left.expr, e2->left.expr);
case E_AND:
case E_OR:
e1 = expr_copy(e1);
e2 = expr_copy(e2);
old_count = trans_count;
expr_eliminate_eq(&e1, &e2);
res = (e1->type == E_SYMBOL && e2->type == E_SYMBOL &&
e1->left.sym == e2->left.sym);
expr_free(e1);
expr_free(e2);
trans_count = old_count;
return res;
case E_LIST:
case E_RANGE:
case E_NONE:
/* panic */;
}
if (DEBUG_EXPR) {
expr_fprint(e1, stdout);
printf(" = ");
expr_fprint(e2, stdout);
printf(" ?\n");
}
return 0;
}
static struct expr *expr_eliminate_yn(struct expr *e)
{
struct expr *tmp;
if (e) switch (e->type) {
case E_AND:
e->left.expr = expr_eliminate_yn(e->left.expr);
e->right.expr = expr_eliminate_yn(e->right.expr);
if (e->left.expr->type == E_SYMBOL) {
if (e->left.expr->left.sym == &symbol_no) {
expr_free(e->left.expr);
expr_free(e->right.expr);
e->type = E_SYMBOL;
e->left.sym = &symbol_no;
e->right.expr = NULL;
return e;
} else if (e->left.expr->left.sym == &symbol_yes) {
free(e->left.expr);
tmp = e->right.expr;
*e = *(e->right.expr);
free(tmp);
return e;
}
}
if (e->right.expr->type == E_SYMBOL) {
if (e->right.expr->left.sym == &symbol_no) {
expr_free(e->left.expr);
expr_free(e->right.expr);
e->type = E_SYMBOL;
e->left.sym = &symbol_no;
e->right.expr = NULL;
return e;
} else if (e->right.expr->left.sym == &symbol_yes) {
free(e->right.expr);
tmp = e->left.expr;
*e = *(e->left.expr);
free(tmp);
return e;
}
}
break;
case E_OR:
e->left.expr = expr_eliminate_yn(e->left.expr);
e->right.expr = expr_eliminate_yn(e->right.expr);
if (e->left.expr->type == E_SYMBOL) {
if (e->left.expr->left.sym == &symbol_no) {
free(e->left.expr);
tmp = e->right.expr;
*e = *(e->right.expr);
free(tmp);
return e;
} else if (e->left.expr->left.sym == &symbol_yes) {
expr_free(e->left.expr);
expr_free(e->right.expr);
e->type = E_SYMBOL;
e->left.sym = &symbol_yes;
e->right.expr = NULL;
return e;
}
}
if (e->right.expr->type == E_SYMBOL) {
if (e->right.expr->left.sym == &symbol_no) {
free(e->right.expr);
tmp = e->left.expr;
*e = *(e->left.expr);
free(tmp);
return e;
} else if (e->right.expr->left.sym == &symbol_yes) {
expr_free(e->left.expr);
expr_free(e->right.expr);
e->type = E_SYMBOL;
e->left.sym = &symbol_yes;
e->right.expr = NULL;
return e;
}
}
break;
default:
;
}
return e;
}
/*
* bool FOO!=n => FOO
*/
struct expr *expr_trans_bool(struct expr *e)
{
if (!e)
return NULL;
switch (e->type) {
case E_AND:
case E_OR:
case E_NOT:
e->left.expr = expr_trans_bool(e->left.expr);
e->right.expr = expr_trans_bool(e->right.expr);
break;
case E_UNEQUAL:
// FOO!=n -> FOO
if (e->left.sym->type == S_TRISTATE) {
if (e->right.sym == &symbol_no) {
e->type = E_SYMBOL;
e->right.sym = NULL;
}
}
break;
default:
;
}
return e;
}
/*
* e1 || e2 -> ?
*/
static struct expr *expr_join_or(struct expr *e1, struct expr *e2)
{
struct expr *tmp;
struct symbol *sym1, *sym2;
if (expr_eq(e1, e2))
return expr_copy(e1);
if (e1->type != E_EQUAL && e1->type != E_UNEQUAL && e1->type != E_SYMBOL && e1->type != E_NOT)
return NULL;
if (e2->type != E_EQUAL && e2->type != E_UNEQUAL && e2->type != E_SYMBOL && e2->type != E_NOT)
return NULL;
if (e1->type == E_NOT) {
tmp = e1->left.expr;
if (tmp->type != E_EQUAL && tmp->type != E_UNEQUAL && tmp->type != E_SYMBOL)
return NULL;
sym1 = tmp->left.sym;
} else
sym1 = e1->left.sym;
if (e2->type == E_NOT) {
if (e2->left.expr->type != E_SYMBOL)
return NULL;
sym2 = e2->left.expr->left.sym;
} else
sym2 = e2->left.sym;
if (sym1 != sym2)
return NULL;
if (sym1->type != S_BOOLEAN && sym1->type != S_TRISTATE)
return NULL;
if (sym1->type == S_TRISTATE) {
if (e1->type == E_EQUAL && e2->type == E_EQUAL &&
((e1->right.sym == &symbol_yes && e2->right.sym == &symbol_mod) ||
(e1->right.sym == &symbol_mod && e2->right.sym == &symbol_yes))) {
// (a='y') || (a='m') -> (a!='n')
return expr_alloc_comp(E_UNEQUAL, sym1, &symbol_no);
}
if (e1->type == E_EQUAL && e2->type == E_EQUAL &&
((e1->right.sym == &symbol_yes && e2->right.sym == &symbol_no) ||
(e1->right.sym == &symbol_no && e2->right.sym == &symbol_yes))) {
// (a='y') || (a='n') -> (a!='m')
return expr_alloc_comp(E_UNEQUAL, sym1, &symbol_mod);
}
if (e1->type == E_EQUAL && e2->type == E_EQUAL &&
((e1->right.sym == &symbol_mod && e2->right.sym == &symbol_no) ||
(e1->right.sym == &symbol_no && e2->right.sym == &symbol_mod))) {
// (a='m') || (a='n') -> (a!='y')
return expr_alloc_comp(E_UNEQUAL, sym1, &symbol_yes);
}
}
if (sym1->type == S_BOOLEAN && sym1 == sym2) {
if ((e1->type == E_NOT && e1->left.expr->type == E_SYMBOL && e2->type == E_SYMBOL) ||
(e2->type == E_NOT && e2->left.expr->type == E_SYMBOL && e1->type == E_SYMBOL))
return expr_alloc_symbol(&symbol_yes);
}
if (DEBUG_EXPR) {
printf("optimize (");
expr_fprint(e1, stdout);
printf(") || (");
expr_fprint(e2, stdout);
printf(")?\n");
}
return NULL;
}
static struct expr *expr_join_and(struct expr *e1, struct expr *e2)
{
struct expr *tmp;
struct symbol *sym1, *sym2;
if (expr_eq(e1, e2))
return expr_copy(e1);
if (e1->type != E_EQUAL && e1->type != E_UNEQUAL && e1->type != E_SYMBOL && e1->type != E_NOT)
return NULL;
if (e2->type != E_EQUAL && e2->type != E_UNEQUAL && e2->type != E_SYMBOL && e2->type != E_NOT)
return NULL;
if (e1->type == E_NOT) {
tmp = e1->left.expr;
if (tmp->type != E_EQUAL && tmp->type != E_UNEQUAL && tmp->type != E_SYMBOL)
return NULL;
sym1 = tmp->left.sym;
} else
sym1 = e1->left.sym;
if (e2->type == E_NOT) {
if (e2->left.expr->type != E_SYMBOL)
return NULL;
sym2 = e2->left.expr->left.sym;
} else
sym2 = e2->left.sym;
if (sym1 != sym2)
return NULL;
if (sym1->type != S_BOOLEAN && sym1->type != S_TRISTATE)
return NULL;
if ((e1->type == E_SYMBOL && e2->type == E_EQUAL && e2->right.sym == &symbol_yes) ||
(e2->type == E_SYMBOL && e1->type == E_EQUAL && e1->right.sym == &symbol_yes))
// (a) && (a='y') -> (a='y')
return expr_alloc_comp(E_EQUAL, sym1, &symbol_yes);
if ((e1->type == E_SYMBOL && e2->type == E_UNEQUAL && e2->right.sym == &symbol_no) ||
(e2->type == E_SYMBOL && e1->type == E_UNEQUAL && e1->right.sym == &symbol_no))
// (a) && (a!='n') -> (a)
return expr_alloc_symbol(sym1);
if ((e1->type == E_SYMBOL && e2->type == E_UNEQUAL && e2->right.sym == &symbol_mod) ||
(e2->type == E_SYMBOL && e1->type == E_UNEQUAL && e1->right.sym == &symbol_mod))
// (a) && (a!='m') -> (a='y')
return expr_alloc_comp(E_EQUAL, sym1, &symbol_yes);
if (sym1->type == S_TRISTATE) {
if (e1->type == E_EQUAL && e2->type == E_UNEQUAL) {
// (a='b') && (a!='c') -> 'b'='c' ? 'n' : a='b'
sym2 = e1->right.sym;
if ((e2->right.sym->flags & SYMBOL_CONST) && (sym2->flags & SYMBOL_CONST))
return sym2 != e2->right.sym ? expr_alloc_comp(E_EQUAL, sym1, sym2)
: expr_alloc_symbol(&symbol_no);
}
if (e1->type == E_UNEQUAL && e2->type == E_EQUAL) {
// (a='b') && (a!='c') -> 'b'='c' ? 'n' : a='b'
sym2 = e2->right.sym;
if ((e1->right.sym->flags & SYMBOL_CONST) && (sym2->flags & SYMBOL_CONST))
return sym2 != e1->right.sym ? expr_alloc_comp(E_EQUAL, sym1, sym2)
: expr_alloc_symbol(&symbol_no);
}
if (e1->type == E_UNEQUAL && e2->type == E_UNEQUAL &&
((e1->right.sym == &symbol_yes && e2->right.sym == &symbol_no) ||
(e1->right.sym == &symbol_no && e2->right.sym == &symbol_yes)))
// (a!='y') && (a!='n') -> (a='m')
return expr_alloc_comp(E_EQUAL, sym1, &symbol_mod);
if (e1->type == E_UNEQUAL && e2->type == E_UNEQUAL &&
((e1->right.sym == &symbol_yes && e2->right.sym == &symbol_mod) ||
(e1->right.sym == &symbol_mod && e2->right.sym == &symbol_yes)))
// (a!='y') && (a!='m') -> (a='n')
return expr_alloc_comp(E_EQUAL, sym1, &symbol_no);
if (e1->type == E_UNEQUAL && e2->type == E_UNEQUAL &&
((e1->right.sym == &symbol_mod && e2->right.sym == &symbol_no) ||
(e1->right.sym == &symbol_no && e2->right.sym == &symbol_mod)))
// (a!='m') && (a!='n') -> (a='m')
return expr_alloc_comp(E_EQUAL, sym1, &symbol_yes);
if ((e1->type == E_SYMBOL && e2->type == E_EQUAL && e2->right.sym == &symbol_mod) ||
(e2->type == E_SYMBOL && e1->type == E_EQUAL && e1->right.sym == &symbol_mod) ||
(e1->type == E_SYMBOL && e2->type == E_UNEQUAL && e2->right.sym == &symbol_yes) ||
(e2->type == E_SYMBOL && e1->type == E_UNEQUAL && e1->right.sym == &symbol_yes))
return NULL;
}
if (DEBUG_EXPR) {
printf("optimize (");
expr_fprint(e1, stdout);
printf(") && (");
expr_fprint(e2, stdout);
printf(")?\n");
}
return NULL;
}
static void expr_eliminate_dups1(enum expr_type type, struct expr **ep1, struct expr **ep2)
{
#define e1 (*ep1)
#define e2 (*ep2)
struct expr *tmp;
if (e1->type == type) {
expr_eliminate_dups1(type, &e1->left.expr, &e2);
expr_eliminate_dups1(type, &e1->right.expr, &e2);
return;
}
if (e2->type == type) {
expr_eliminate_dups1(type, &e1, &e2->left.expr);
expr_eliminate_dups1(type, &e1, &e2->right.expr);
return;
}
if (e1 == e2)
return;
switch (e1->type) {
case E_OR: case E_AND:
expr_eliminate_dups1(e1->type, &e1, &e1);
default:
;
}
switch (type) {
case E_OR:
tmp = expr_join_or(e1, e2);
if (tmp) {
expr_free(e1); expr_free(e2);
e1 = expr_alloc_symbol(&symbol_no);
e2 = tmp;
trans_count++;
}
break;
case E_AND:
tmp = expr_join_and(e1, e2);
if (tmp) {
expr_free(e1); expr_free(e2);
e1 = expr_alloc_symbol(&symbol_yes);
e2 = tmp;
trans_count++;
}
break;
default:
;
}
#undef e1
#undef e2
}
struct expr *expr_eliminate_dups(struct expr *e)
{
int oldcount;
if (!e)
return e;
oldcount = trans_count;
while (1) {
trans_count = 0;
switch (e->type) {
case E_OR: case E_AND:
expr_eliminate_dups1(e->type, &e, &e);
default:
;
}
if (!trans_count)
break;
e = expr_eliminate_yn(e);
}
trans_count = oldcount;
return e;
}
struct expr *expr_transform(struct expr *e)
{
struct expr *tmp;
if (!e)
return NULL;
switch (e->type) {
case E_EQUAL:
case E_UNEQUAL:
case E_SYMBOL:
case E_LIST:
break;
default:
e->left.expr = expr_transform(e->left.expr);
e->right.expr = expr_transform(e->right.expr);
}
switch (e->type) {
case E_EQUAL:
if (e->left.sym->type != S_BOOLEAN)
break;
if (e->right.sym == &symbol_no) {
e->type = E_NOT;
e->left.expr = expr_alloc_symbol(e->left.sym);
e->right.sym = NULL;
break;
}
if (e->right.sym == &symbol_mod) {
printf("boolean symbol %s tested for 'm'? test forced to 'n'\n", e->left.sym->name);
e->type = E_SYMBOL;
e->left.sym = &symbol_no;
e->right.sym = NULL;
break;
}
if (e->right.sym == &symbol_yes) {
e->type = E_SYMBOL;
e->right.sym = NULL;
break;
}
break;
case E_UNEQUAL:
if (e->left.sym->type != S_BOOLEAN)
break;
if (e->right.sym == &symbol_no) {
e->type = E_SYMBOL;
e->right.sym = NULL;
break;
}
if (e->right.sym == &symbol_mod) {
printf("boolean symbol %s tested for 'm'? test forced to 'y'\n", e->left.sym->name);
e->type = E_SYMBOL;
e->left.sym = &symbol_yes;
e->right.sym = NULL;
break;
}
if (e->right.sym == &symbol_yes) {
e->type = E_NOT;
e->left.expr = expr_alloc_symbol(e->left.sym);
e->right.sym = NULL;
break;
}
break;
case E_NOT:
switch (e->left.expr->type) {
case E_NOT:
// !!a -> a
tmp = e->left.expr->left.expr;
free(e->left.expr);
free(e);
e = tmp;
e = expr_transform(e);
break;
case E_EQUAL:
case E_UNEQUAL:
// !a='x' -> a!='x'
tmp = e->left.expr;
free(e);
e = tmp;
e->type = e->type == E_EQUAL ? E_UNEQUAL : E_EQUAL;
break;
case E_OR:
// !(a || b) -> !a && !b
tmp = e->left.expr;
e->type = E_AND;
e->right.expr = expr_alloc_one(E_NOT, tmp->right.expr);
tmp->type = E_NOT;
tmp->right.expr = NULL;
e = expr_transform(e);
break;
case E_AND:
// !(a && b) -> !a || !b
tmp = e->left.expr;
e->type = E_OR;
e->right.expr = expr_alloc_one(E_NOT, tmp->right.expr);
tmp->type = E_NOT;
tmp->right.expr = NULL;
e = expr_transform(e);
break;
case E_SYMBOL:
if (e->left.expr->left.sym == &symbol_yes) {
// !'y' -> 'n'
tmp = e->left.expr;
free(e);
e = tmp;
e->type = E_SYMBOL;
e->left.sym = &symbol_no;
break;
}
if (e->left.expr->left.sym == &symbol_mod) {
// !'m' -> 'm'
tmp = e->left.expr;
free(e);
e = tmp;
e->type = E_SYMBOL;
e->left.sym = &symbol_mod;
break;
}
if (e->left.expr->left.sym == &symbol_no) {
// !'n' -> 'y'
tmp = e->left.expr;
free(e);
e = tmp;
e->type = E_SYMBOL;
e->left.sym = &symbol_yes;
break;
}
break;
default:
;
}
break;
default:
;
}
return e;
}
int expr_contains_symbol(struct expr *dep, struct symbol *sym)
{
if (!dep)
return 0;
switch (dep->type) {
case E_AND:
case E_OR:
return expr_contains_symbol(dep->left.expr, sym) ||
expr_contains_symbol(dep->right.expr, sym);
case E_SYMBOL:
return dep->left.sym == sym;
case E_EQUAL:
case E_UNEQUAL:
return dep->left.sym == sym ||
dep->right.sym == sym;
case E_NOT:
return expr_contains_symbol(dep->left.expr, sym);
default:
;
}
return 0;
}
bool expr_depends_symbol(struct expr *dep, struct symbol *sym)
{
if (!dep)
return false;
switch (dep->type) {
case E_AND:
return expr_depends_symbol(dep->left.expr, sym) ||
expr_depends_symbol(dep->right.expr, sym);
case E_SYMBOL:
return dep->left.sym == sym;
case E_EQUAL:
if (dep->left.sym == sym) {
if (dep->right.sym == &symbol_yes || dep->right.sym == &symbol_mod)
return true;
}
break;
case E_UNEQUAL:
if (dep->left.sym == sym) {
if (dep->right.sym == &symbol_no)
return true;
}
break;
default:
;
}
return false;
}
struct expr *expr_trans_compare(struct expr *e, enum expr_type type, struct symbol *sym)
{
struct expr *e1, *e2;
if (!e) {
e = expr_alloc_symbol(sym);
if (type == E_UNEQUAL)
e = expr_alloc_one(E_NOT, e);
return e;
}
switch (e->type) {
case E_AND:
e1 = expr_trans_compare(e->left.expr, E_EQUAL, sym);
e2 = expr_trans_compare(e->right.expr, E_EQUAL, sym);
if (sym == &symbol_yes)
e = expr_alloc_two(E_AND, e1, e2);
if (sym == &symbol_no)
e = expr_alloc_two(E_OR, e1, e2);
if (type == E_UNEQUAL)
e = expr_alloc_one(E_NOT, e);
return e;
case E_OR:
e1 = expr_trans_compare(e->left.expr, E_EQUAL, sym);
e2 = expr_trans_compare(e->right.expr, E_EQUAL, sym);
if (sym == &symbol_yes)
e = expr_alloc_two(E_OR, e1, e2);
if (sym == &symbol_no)
e = expr_alloc_two(E_AND, e1, e2);
if (type == E_UNEQUAL)
e = expr_alloc_one(E_NOT, e);
return e;
case E_NOT:
return expr_trans_compare(e->left.expr, type == E_EQUAL ? E_UNEQUAL : E_EQUAL, sym);
case E_UNEQUAL:
case E_EQUAL:
if (type == E_EQUAL) {
if (sym == &symbol_yes)
return expr_copy(e);
if (sym == &symbol_mod)
return expr_alloc_symbol(&symbol_no);
if (sym == &symbol_no)
return expr_alloc_one(E_NOT, expr_copy(e));
} else {
if (sym == &symbol_yes)
return expr_alloc_one(E_NOT, expr_copy(e));
if (sym == &symbol_mod)
return expr_alloc_symbol(&symbol_yes);
if (sym == &symbol_no)
return expr_copy(e);
}
break;
case E_SYMBOL:
return expr_alloc_comp(type, e->left.sym, sym);
case E_LIST:
case E_RANGE:
case E_NONE:
/* panic */;
}
return NULL;
}
tristate expr_calc_value(struct expr *e)
{
tristate val1, val2;
const char *str1, *str2;
if (!e)
return yes;
switch (e->type) {
case E_SYMBOL:
sym_calc_value(e->left.sym);
return e->left.sym->curr.tri;
case E_AND:
val1 = expr_calc_value(e->left.expr);
val2 = expr_calc_value(e->right.expr);
return EXPR_AND(val1, val2);
case E_OR:
val1 = expr_calc_value(e->left.expr);
val2 = expr_calc_value(e->right.expr);
return EXPR_OR(val1, val2);
case E_NOT:
val1 = expr_calc_value(e->left.expr);
return EXPR_NOT(val1);
case E_EQUAL:
sym_calc_value(e->left.sym);
sym_calc_value(e->right.sym);
str1 = sym_get_string_value(e->left.sym);
str2 = sym_get_string_value(e->right.sym);
return !strcmp(str1, str2) ? yes : no;
case E_UNEQUAL:
sym_calc_value(e->left.sym);
sym_calc_value(e->right.sym);
str1 = sym_get_string_value(e->left.sym);
str2 = sym_get_string_value(e->right.sym);
return !strcmp(str1, str2) ? no : yes;
default:
printf("expr_calc_value: %d?\n", e->type);
return no;
}
}
static int expr_compare_type(enum expr_type t1, enum expr_type t2)
{
if (t1 == t2)
return 0;
switch (t1) {
case E_EQUAL:
case E_UNEQUAL:
if (t2 == E_NOT)
return 1;
case E_NOT:
if (t2 == E_AND)
return 1;
case E_AND:
if (t2 == E_OR)
return 1;
case E_OR:
if (t2 == E_LIST)
return 1;
case E_LIST:
if (t2 == 0)
return 1;
default:
return -1;
}
printf("[%dgt%d?]", t1, t2);
return 0;
}
static inline struct expr *
expr_get_leftmost_symbol(const struct expr *e)
{
if (e == NULL)
return NULL;
while (e->type != E_SYMBOL)
e = e->left.expr;
return expr_copy(e);
}
/*
* Given expression `e1' and `e2', returns the leaf of the longest
* sub-expression of `e1' not containing 'e2.
*/
struct expr *expr_simplify_unmet_dep(struct expr *e1, struct expr *e2)
{
struct expr *ret;
switch (e1->type) {
case E_OR:
return expr_alloc_and(
expr_simplify_unmet_dep(e1->left.expr, e2),
expr_simplify_unmet_dep(e1->right.expr, e2));
case E_AND: {
struct expr *e;
e = expr_alloc_and(expr_copy(e1), expr_copy(e2));
e = expr_eliminate_dups(e);
ret = (!expr_eq(e, e1)) ? e1 : NULL;
expr_free(e);
break;
}
default:
ret = e1;
break;
}
return expr_get_leftmost_symbol(ret);
}
void expr_print(struct expr *e, void (*fn)(void *, struct symbol *, const char *), void *data, int prevtoken)
{
if (!e) {
fn(data, NULL, "y");
return;
}
if (expr_compare_type(prevtoken, e->type) > 0)
fn(data, NULL, "(");
switch (e->type) {
case E_SYMBOL:
if (e->left.sym->name)
fn(data, e->left.sym, e->left.sym->name);
else
fn(data, NULL, "<choice>");
break;
case E_NOT:
fn(data, NULL, "!");
expr_print(e->left.expr, fn, data, E_NOT);
break;
case E_EQUAL:
if (e->left.sym->name)
fn(data, e->left.sym, e->left.sym->name);
else
fn(data, NULL, "<choice>");
fn(data, NULL, "=");
fn(data, e->right.sym, e->right.sym->name);
break;
case E_UNEQUAL:
if (e->left.sym->name)
fn(data, e->left.sym, e->left.sym->name);
else
fn(data, NULL, "<choice>");
fn(data, NULL, "!=");
fn(data, e->right.sym, e->right.sym->name);
break;
case E_OR:
expr_print(e->left.expr, fn, data, E_OR);
fn(data, NULL, " || ");
expr_print(e->right.expr, fn, data, E_OR);
break;
case E_AND:
expr_print(e->left.expr, fn, data, E_AND);
fn(data, NULL, " && ");
expr_print(e->right.expr, fn, data, E_AND);
break;
case E_LIST:
fn(data, e->right.sym, e->right.sym->name);
if (e->left.expr) {
fn(data, NULL, " ^ ");
expr_print(e->left.expr, fn, data, E_LIST);
}
break;
case E_RANGE:
fn(data, NULL, "[");
fn(data, e->left.sym, e->left.sym->name);
fn(data, NULL, " ");
fn(data, e->right.sym, e->right.sym->name);
fn(data, NULL, "]");
break;
default:
{
char buf[32];
sprintf(buf, "<unknown type %d>", e->type);
fn(data, NULL, buf);
break;
}
}
if (expr_compare_type(prevtoken, e->type) > 0)
fn(data, NULL, ")");
}
static void expr_print_file_helper(void *data, struct symbol *sym, const char *str)
{
xfwrite(str, strlen(str), 1, data);
}
void expr_fprint(struct expr *e, FILE *out)
{
expr_print(e, expr_print_file_helper, out, E_NONE);
}
static void expr_print_gstr_helper(void *data, struct symbol *sym, const char *str)
{
struct gstr *gs = (struct gstr*)data;
const char *sym_str = NULL;
if (sym)
sym_str = sym_get_string_value(sym);
if (gs->max_width) {
unsigned extra_length = strlen(str);
const char *last_cr = strrchr(gs->s, '\n');
unsigned last_line_length;
if (sym_str)
extra_length += 4 + strlen(sym_str);
if (!last_cr)
last_cr = gs->s;
last_line_length = strlen(gs->s) - (last_cr - gs->s);
if ((last_line_length + extra_length) > gs->max_width)
str_append(gs, "\\\n");
}
str_append(gs, str);
if (sym && sym->type != S_UNKNOWN)
str_printf(gs, " [=%s]", sym_str);
}
void expr_gstr_print(struct expr *e, struct gstr *gs)
{
expr_print(e, expr_print_gstr_helper, gs, E_NONE);
}
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