pangen4.c

这是一个同样来自贝尔实验室的和UNIX有着渊源的操作系统, 其简洁的设计和实现易于我们学习和理解

/***** spin: pangen4.c *****/

/* Copyright (c) 1989-2003 by Lucent Technologies, Bell Laboratories.     */
/* All Rights Reserved.  This software is for educational purposes only.  */
/* No guarantee whatsoever is expressed or implied by the distribution of */
/* this code.  Permission is given to distribute this code provided that  */
/* this introductory message is not removed and no monies are exchanged.  */
/* Software written by Gerard J. Holzmann.  For tool documentation see:   */
/*             http://spinroot.com/                                       */
/* Send all bug-reports and/or questions to: [e-mail]            */

#include "spin.h"
#ifdef PC
#include "y_tab.h"
#else
#include "y.tab.h"
#endif

extern FILE	*tc, *tb;
extern Queue	*qtab;
extern Symbol	*Fname;
extern int	lineno, m_loss, Pid, eventmapnr, multi_oval;
extern short	nocast, has_provided, has_sorted;
extern char	*R13[], *R14[], *R15[];

static void	check_proc(Lextok *, int);

void
undostmnt(Lextok *now, int m)
{	Lextok *v;
	int i, j;

	if (!now)
	{	fprintf(tb, "0");
		return;
	}
	lineno = now->ln;
	Fname  = now->fn;
	switch (now->ntyp) {
	case CONST:	case '!':	case UMIN:
	case '~':	case '/':	case '*':
	case '-':	case '+':	case '%':
	case LT:	case GT:	case '&':
	case '|':	case LE:	case GE:
	case NE:	case EQ:	case OR:
	case AND:	case LSHIFT:	case RSHIFT:
	case TIMEOUT:	case LEN:	case NAME:
	case FULL:	case EMPTY:	case 'R':
	case NFULL:	case NEMPTY:	case ENABLED:
	case '?':	case PC_VAL:	case '^':
	case C_EXPR:
	case NONPROGRESS:
		putstmnt(tb, now, m);
		break;

	case RUN:
		fprintf(tb, "delproc(0, now._nr_pr-1)");
		break;

	case 's':
		if (Pid == eventmapnr) break;

		if (m_loss)
			fprintf(tb, "if (_m == 2) ");
		putname(tb, "_m = unsend(", now->lft, m, ")");
		break;

	case 'r':
		if (Pid == eventmapnr) break;

		for (v = now->rgt, i=j=0; v; v = v->rgt, i++)
			if (v->lft->ntyp != CONST
			&&  v->lft->ntyp != EVAL)
				j++;
		if (j == 0 && now->val >= 2)
			break;	/* poll without side-effect */

		{	int ii = 0, jj;

			for (v = now->rgt; v; v = v->rgt)
				if ((v->lft->ntyp != CONST
				&&   v->lft->ntyp != EVAL))
					ii++;	/* nr of things bupped */
			if (now->val == 1)
			{	ii++;
				jj = multi_oval - ii - 1;
				fprintf(tb, "XX = trpt->bup.oval");
				if (multi_oval > 0)
				{	fprintf(tb, "s[%d]", jj);
					jj++;
				}
				fprintf(tb, ";\n\t\t");
			} else
			{	fprintf(tb, "XX = 1;\n\t\t");
				jj = multi_oval - ii - 1;
			}

			if (now->val < 2)	/* not for channel poll */
			for (v = now->rgt, i = 0; v; v = v->rgt, i++)
			{	switch(v->lft->ntyp) {
				case CONST:
				case EVAL:
					fprintf(tb, "unrecv");
					putname(tb, "(", now->lft, m, ", XX-1, ");
					fprintf(tb, "%d, ", i);
					if (v->lft->ntyp == EVAL)
						undostmnt(v->lft->lft, m);
					else
						undostmnt(v->lft, m);
					fprintf(tb, ", %d);\n\t\t", (i==0)?1:0);
					break;
				default:
					fprintf(tb, "unrecv");
					putname(tb, "(", now->lft, m, ", XX-1, ");
					fprintf(tb, "%d, ", i);
					if (v->lft->sym
					&& !strcmp(v->lft->sym->name, "_"))
					{	fprintf(tb, "trpt->bup.oval");
						if (multi_oval > 0)
							fprintf(tb, "s[%d]", jj);
					} else
						putstmnt(tb, v->lft, m);

					fprintf(tb, ", %d);\n\t\t", (i==0)?1:0);
					if (multi_oval > 0)
						jj++;
					break;
			}	}
			jj = multi_oval - ii - 1;

			if (now->val == 1 && multi_oval > 0)
				jj++;	/* new 3.4.0 */

			for (v = now->rgt, i = 0; v; v = v->rgt, i++)
			{	switch(v->lft->ntyp) {
				case CONST:
				case EVAL:
					break;
				default:
					if (!v->lft->sym
					||  strcmp(v->lft->sym->name, "_") != 0)
					{	nocast=1; putstmnt(tb,v->lft,m);
						nocast=0; fprintf(tb, " = trpt->bup.oval");
						if (multi_oval > 0)
							fprintf(tb, "s[%d]", jj);
						fprintf(tb, ";\n\t\t");
					}
					if (multi_oval > 0)
						jj++;
					break;
			}	}
			multi_oval -= ii;
		}
		break;

	case '@':
		fprintf(tb, "p_restor(II);\n\t\t");
		break;

	case ASGN:
		nocast=1; putstmnt(tb,now->lft,m);
		nocast=0; fprintf(tb, " = trpt->bup.oval");
		if (multi_oval > 0)
		{	multi_oval--;
			fprintf(tb, "s[%d]", multi_oval-1);
		}
		check_proc(now->rgt, m);
		break;

	case 'c':
		check_proc(now->lft, m);
		break;

	case '.':
	case GOTO:
	case ELSE:
	case BREAK:
		break;

	case C_CODE:
		fprintf(tb, "sv_restor();\n");
		break;

	case ASSERT:
	case PRINT:
		check_proc(now, m);
		break;
	case PRINTM:
		break;

	default:
		printf("spin: bad node type %d (.b)\n", now->ntyp);
		alldone(1);
	}
}

int
any_undo(Lextok *now)
{	/* is there anything to undo on a return move? */
	if (!now) return 1;
	switch (now->ntyp) {
	case 'c':	return any_oper(now->lft, RUN);
	case ASSERT:
	case PRINT:	return any_oper(now, RUN);

	case PRINTM:
	case   '.':
	case  GOTO:
	case  ELSE:
	case BREAK:	return 0;
	default:	return 1;
	}
}

int
any_oper(Lextok *now, int oper)
{	/* check if an expression contains oper operator */
	if (!now) return 0;
	if (now->ntyp == oper)
		return 1;
	return (any_oper(now->lft, oper) || any_oper(now->rgt, oper));
}

static void
check_proc(Lextok *now, int m)
{
	if (!now)
		return;
	if (now->ntyp == '@' || now->ntyp == RUN)
	{	fprintf(tb, ";\n\t\t");
		undostmnt(now, m);
	}
	check_proc(now->lft, m);
	check_proc(now->rgt, m);
}

void
genunio(void)
{	char buf1[256];
	Queue *q; int i;

	ntimes(tc, 0, 1, R13);
	for (q = qtab; q; q = q->nxt)
	{	fprintf(tc, "\tcase %d:\n", q->qid);

		if (has_sorted)
		{	sprintf(buf1, "((Q%d *)z)->contents", q->qid);
			fprintf(tc, "#ifdef HAS_SORTED\n");
			fprintf(tc, "\t\tj = trpt->ipt;\n");	/* ipt was bup.oval */
			fprintf(tc, "#endif\n");
			fprintf(tc, "\t\tfor (k = j; k < ((Q%d *)z)->Qlen; k++)\n",
				q->qid);
			fprintf(tc, "\t\t{\n");
			for (i = 0; i < q->nflds; i++)
			fprintf(tc, "\t\t\t%s[k].fld%d = %s[k+1].fld%d;\n",
				buf1, i, buf1, i);
			fprintf(tc, "\t\t}\n");
			fprintf(tc, "\t\tj = ((Q0 *)z)->Qlen;\n");
		}

		sprintf(buf1, "((Q%d *)z)->contents[j].fld", q->qid);
		for (i = 0; i < q->nflds; i++)
			fprintf(tc, "\t\t%s%d = 0;\n", buf1, i);
		if (q->nslots==0)
		{	/* check if rendezvous succeeded, 1 level down */
			fprintf(tc, "\t\t_m = (trpt+1)->o_m;\n");
			fprintf(tc, "\t\tif (_m) (trpt-1)->o_pm |= 1;\n");
			fprintf(tc, "\t\tUnBlock;\n");
		} else
			fprintf(tc, "\t\t_m = trpt->o_m;\n");

		fprintf(tc, "\t\tbreak;\n");
	}
	ntimes(tc, 0, 1, R14);
	for (q = qtab; q; q = q->nxt)
	{	sprintf(buf1, "((Q%d *)z)->contents", q->qid);
		fprintf(tc, "	case %d:\n", q->qid);
		if (q->nslots == 0)
			fprintf(tc, "\t\tif (strt) boq = from+1;\n");
		else if (q->nslots > 1)	/* shift */
		{	fprintf(tc, "\t\tif (strt && slot<%d)\n",
							q->nslots-1);
			fprintf(tc, "\t\t{\tfor (j--; j>=slot; j--)\n");
			fprintf(tc, "\t\t\t{");
			for (i = 0; i < q->nflds; i++)
			{	fprintf(tc, "\t%s[j+1].fld%d =\n\t\t\t",
							buf1, i);
				fprintf(tc, "\t%s[j].fld%d;\n\t\t\t",
							buf1, i);
			}
			fprintf(tc, "}\n\t\t}\n");
		}
		strcat(buf1, "[slot].fld");
		fprintf(tc, "\t\tif (strt) {\n");
		for (i = 0; i < q->nflds; i++)
			fprintf(tc, "\t\t\t%s%d = 0;\n", buf1, i);
		fprintf(tc, "\t\t}\n");
		if (q->nflds == 1)	/* set */
			fprintf(tc, "\t\tif (fld == 0) %s0 = fldvar;\n",
							buf1);
		else
		{	fprintf(tc, "\t\tswitch (fld) {\n");
			for (i = 0; i < q->nflds; i++)
			{	fprintf(tc, "\t\tcase %d:\t%s", i, buf1);
				fprintf(tc, "%d = fldvar; break;\n", i);
			}
			fprintf(tc, "\t\t}\n");
		}
		fprintf(tc, "\t\tbreak;\n");
	}
	ntimes(tc, 0, 1, R15);
}

int
proper_enabler(Lextok *n)
{
	if (!n) return 1;
	switch (n->ntyp) {
	case NEMPTY:	case FULL:
	case NFULL:	case EMPTY:
	case LEN:	case 'R':
	case NAME:
		has_provided = 1;
		if (strcmp(n->sym->name, "_pid") == 0)
			return 1;
		return (!(n->sym->context));

	case CONST:	case TIMEOUT:
		has_provided = 1;
		return 1;

	case ENABLED:	case PC_VAL:
		return proper_enabler(n->lft);

	case '!': case UMIN: case '~':
		return proper_enabler(n->lft);

	case '/': case '*': case '-': case '+':
	case '%': case LT:  case GT: case '&': case '^':
	case '|': case LE:  case GE:  case NE: case '?':
	case EQ:  case OR:  case AND: case LSHIFT:
	case RSHIFT: case 'c':
		return proper_enabler(n->lft) && proper_enabler(n->rgt);
	default:
		break;
	}
	return 0;
}