expr.c

用于生成linux操作系统下的交叉编译工具链和嵌入式linux系统的根文件系统,支持x86、arm、powerpc等处理器

/*
 * Copyright (C) 2002 Roman Zippel <[e-mail]>
 * Released under the terms of the GNU GPL v2.0.
 */

#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#define LKC_DIRECT_LINK
#include "lkc.h"

#define DEBUG_EXPR	0

struct expr *expr_alloc_symbol(struct symbol *sym)
{
	struct expr *e = malloc(sizeof(*e));
	memset(e, 0, 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 = malloc(sizeof(*e));
	memset(e, 0, 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 = malloc(sizeof(*e));
	memset(e, 0, 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 = malloc(sizeof(*e));
	memset(e, 0, 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(struct expr *org)
{
	struct expr *e;

	if (!org)
		return NULL;

	e = malloc(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_CHOICE:
		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->flags & (SYMBOL_YES|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

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_CHOICE:
	case E_RANGE:
	case E_NONE:
		/* panic */;
	}

	if (DEBUG_EXPR) {
		expr_fprint(e1, stdout);
		printf(" = ");
		expr_fprint(e2, stdout);
		printf(" ?\n");
	}

	return 0;
}

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 -> ?
 */
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;
}

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);