spinlex.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

c_preview(void)
{	C_Added *r;

	hastrack = 0;
	if (c_tracked)
		hastrack = 1;
	else
	for (r = c_added; r; r = r->nxt)
		if (strncmp(r->t->name, " Global ", strlen(" Global ")) != 0
		&&  strncmp(r->t->name, " Hidden ", strlen(" Hidden ")) != 0
		&&  strncmp(r->t->name, " Local",  strlen(" Local"))  != 0)
		{	hastrack = 1;	/* c_state variant now obsolete */
			break;
		}
}

int
c_add_sv(FILE *fd)	/* 1+2 -- called in pangen1.c */
{	C_Added *r;
	int cnt = 0;

	if (!c_added && !c_tracked) return 0;

	for (r = c_added; r; r = r->nxt)	/* pickup global decls */
		if (strncmp(r->t->name, " Global ", strlen(" Global ")) == 0)
			fprintf(fd, "	%s;\n", r->s->name);

	for (r = c_added; r; r = r->nxt)
		if (strncmp(r->t->name, " Global ", strlen(" Global ")) != 0
		&&  strncmp(r->t->name, " Hidden ", strlen(" Hidden ")) != 0
		&&  strncmp(r->t->name, " Local",  strlen(" Local"))  != 0)
		{	cnt++;	/* obsolete use */
		}

	for (r = c_tracked; r; r = r->nxt)
		cnt++;		/* preferred use */

	if (cnt == 0) return 0;

	cnt = 0;
	fprintf(fd, "	uchar c_state[");
	for (r = c_added; r; r = r->nxt)
		if (strncmp(r->t->name, " Global ", strlen(" Global ")) != 0
		&&  strncmp(r->t->name, " Hidden ", strlen(" Hidden ")) != 0
		&&  strncmp(r->t->name, " Local",  strlen(" Local"))  != 0)
		{	fprintf(fd, "%ssizeof(%s)",
				(cnt==0)?"":"+", r->t->name);
			cnt++;
		}

	for (r = c_tracked; r; r = r->nxt)
	{	if (r->ival != ZS) continue;

		fprintf(fd, "%s%s",
			(cnt==0)?"":"+", r->t->name);
		cnt++;
	}

	if (cnt == 0) fprintf(fd, "4");	/* now redundant */
	fprintf(fd, "];\n");
	return 1;
}

void
c_add_stack(FILE *fd)
{	C_Added *r;
	int cnt = 0;

	if ((!c_added && !c_tracked) || !has_stack) return;


	for (r = c_tracked; r; r = r->nxt)
		if (r->ival != ZS)
			cnt++;

	if (cnt == 0) return;

	fprintf(fd, "	uchar c_stack[");

	cnt = 0;
	for (r = c_tracked; r; r = r->nxt)
	{	if (r->ival == ZS) continue;

		fprintf(fd, "%s%s",
			(cnt==0)?"":"+", r->t->name);
		cnt++;
	}

	if (cnt == 0) fprintf(fd, "4"); /* can't happen */
	fprintf(fd, "];\n");
}

void
c_add_hidden(FILE *fd)
{	C_Added *r;

	for (r = c_added; r; r = r->nxt)	/* pickup hidden decls */
		if (strncmp(r->t->name, "\"Hidden\"", strlen("\"Hidden\"")) == 0)
		{	r->s->name[strlen(r->s->name)-1] = ' ';
			fprintf(fd, "%s;	/* Hidden */\n", &r->s->name[1]);
			r->s->name[strlen(r->s->name)-1] = '"';
		}
	/* called before c_add_def - quotes are still there */
}

void
c_add_loc(FILE *fd, char *s)	/* state vector entries for proctype s */
{	C_Added *r;
	static char buf[1024];
	char *p;

	if (!c_added) return;

	strcpy(buf, s);
	strcat(buf, " ");
	for (r = c_added; r; r = r->nxt)	/* pickup local decls */
		if (strncmp(r->t->name, " Local", strlen(" Local")) == 0)
		{	p = r->t->name + strlen(" Local");
			while (*p == ' ' || *p == '\t')
				p++;
			if (strcmp(p, buf) == 0)
				fprintf(fd, "	%s;\n", r->s->name);
		}
}
void
c_add_def(FILE *fd)	/* 3 - called in plunk_c_fcts() */
{	C_Added *r;

	fprintf(fd, "#if defined(C_States) && defined(HAS_TRACK)\n");
	for (r = c_added; r; r = r->nxt)
	{	r->s->name[strlen(r->s->name)-1] = ' ';
		r->s->name[0] = ' '; /* remove the "s */

		r->t->name[strlen(r->t->name)-1] = ' ';
		r->t->name[0] = ' ';

		if (strncmp(r->t->name, " Global ", strlen(" Global ")) == 0
		||  strncmp(r->t->name, " Hidden ", strlen(" Hidden ")) == 0
		||  strncmp(r->t->name, " Local",  strlen(" Local"))  == 0)
			continue;

		if (strchr(r->s->name, '&'))
			fatal("dereferencing state object: %s", r->s->name);

		fprintf(fd, "extern %s %s;\n", r->t->name, r->s->name);
	}
	for (r = c_tracked; r; r = r->nxt)
	{	r->s->name[strlen(r->s->name)-1] = ' ';
		r->s->name[0] = ' '; /* remove " */

		r->t->name[strlen(r->t->name)-1] = ' ';
		r->t->name[0] = ' ';
	}

	if (separate == 2)
	{	fprintf(fd, "#endif\n");
		return;
	}

	if (has_stack)
	{	fprintf(fd, "void\nc_stack(char *p_t_r)\n{\n");
		fprintf(fd, "#ifdef VERBOSE\n");
		fprintf(fd, "	printf(\"c_stack %%u\\n\", p_t_r);\n");
		fprintf(fd, "#endif\n");
		for (r = c_tracked; r; r = r->nxt)
		{	if (r->ival == ZS) continue;
	
			fprintf(fd, "\tif(%s)\n", r->s->name);
			fprintf(fd, "\t\tmemcpy(p_t_r, %s, %s);\n",
				r->s->name, r->t->name);
			fprintf(fd, "\telse\n");
			fprintf(fd, "\t\tmemset(p_t_r, 0, %s);\n",
				r->t->name);
			fprintf(fd, "\tp_t_r += %s;\n", r->t->name);
		}
		fprintf(fd, "}\n\n");
	}

	fprintf(fd, "void\nc_update(char *p_t_r)\n{\n");
	fprintf(fd, "#ifdef VERBOSE\n");
	fprintf(fd, "	printf(\"c_update %%u\\n\", p_t_r);\n");
	fprintf(fd, "#endif\n");
	for (r = c_added; r; r = r->nxt)
	{	if (strncmp(r->t->name, " Global ", strlen(" Global ")) == 0
		||  strncmp(r->t->name, " Hidden ", strlen(" Hidden ")) == 0
		||  strncmp(r->t->name, " Local",  strlen(" Local"))  == 0)
			continue;

		fprintf(fd, "\tmemcpy(p_t_r, &%s, sizeof(%s));\n",
			r->s->name, r->t->name);
		fprintf(fd, "\tp_t_r += sizeof(%s);\n", r->t->name);
	}

	for (r = c_tracked; r; r = r->nxt)
	{	if (r->ival) continue;

		fprintf(fd, "\tif(%s)\n", r->s->name);
		fprintf(fd, "\t\tmemcpy(p_t_r, %s, %s);\n",
			r->s->name, r->t->name);
		fprintf(fd, "\telse\n");
		fprintf(fd, "\t\tmemset(p_t_r, 0, %s);\n",
			r->t->name);
		fprintf(fd, "\tp_t_r += %s;\n", r->t->name);
	}

	fprintf(fd, "}\n");

	if (has_stack)
	{	fprintf(fd, "void\nc_unstack(char *p_t_r)\n{\n");
		fprintf(fd, "#ifdef VERBOSE\n");
		fprintf(fd, "	printf(\"c_unstack %%u\\n\", p_t_r);\n");
		fprintf(fd, "#endif\n");
		for (r = c_tracked; r; r = r->nxt)
		{	if (r->ival == ZS) continue;

			fprintf(fd, "\tif(%s)\n", r->s->name);
			fprintf(fd, "\t\tmemcpy(%s, p_t_r, %s);\n",
				r->s->name, r->t->name);
			fprintf(fd, "\tp_t_r += %s;\n", r->t->name);
		}
		fprintf(fd, "}\n");
	}

	fprintf(fd, "void\nc_revert(char *p_t_r)\n{\n");
	fprintf(fd, "#ifdef VERBOSE\n");
	fprintf(fd, "	printf(\"c_revert %%u\\n\", p_t_r);\n");
	fprintf(fd, "#endif\n");
	for (r = c_added; r; r = r->nxt)
	{	if (strncmp(r->t->name, " Global ", strlen(" Global ")) == 0
		||  strncmp(r->t->name, " Hidden ", strlen(" Hidden ")) == 0
		||  strncmp(r->t->name, " Local",  strlen(" Local"))  == 0)
			continue;

		fprintf(fd, "\tmemcpy(&%s, p_t_r, sizeof(%s));\n",
			r->s->name, r->t->name);
		fprintf(fd, "\tp_t_r += sizeof(%s);\n", r->t->name);
	}
	for (r = c_tracked; r; r = r->nxt)
	{	if (r->ival != ZS) continue;

		fprintf(fd, "\tif(%s)\n", r->s->name);
		fprintf(fd, "\t\tmemcpy(%s, p_t_r, %s);\n",
			r->s->name, r->t->name);
		fprintf(fd, "\tp_t_r += %s;\n", r->t->name);
	}

	fprintf(fd, "}\n");
	fprintf(fd, "#endif\n");
}

void
plunk_reverse(FILE *fd, IType *p, int matchthis)
{	char *y, *z;

	if (!p) return;
	plunk_reverse(fd, p->nxt, matchthis);

	if (!p->nm->context
	&&   p->nm->type == matchthis)
	{	fprintf(fd, "\n/* start of %s */\n", p->nm->name);
		z = (char *) p->cn;
		while (*z == '\n' || *z == '\r' || *z == '\\')
			z++;
		/* e.g.: \#include "..." */

		y = z;
		while ((y = strstr(y, "\\#")) != NULL)
		{	*y = '\n'; y++;
		}

		fprintf(fd, "%s\n", z);
		fprintf(fd, "\n/* end of %s */\n", p->nm->name);
	}
}

void
plunk_c_decls(FILE *fd)
{
	plunk_reverse(fd, seqnames, CODE_DECL);
}

void
plunk_c_fcts(FILE *fd)
{
	if (separate == 2 && hastrack)
	{	c_add_def(fd);
		return;
	}

	c_add_hidden(fd);
	plunk_reverse(fd, seqnames, CODE_FRAG);

	if (c_added || c_tracked)	/* enables calls to c_revert and c_update */
		fprintf(fd, "#define C_States	1\n");
	else
		fprintf(fd, "#undef C_States\n");

	if (hastrack)
		c_add_def(fd);

	c_add_globinit(fd);
	do_locinits(fd);
}

static void
check_inline(IType *tmp)
{	char buf[128];
	ProcList *p;

	if (!X) return;

	for (p = rdy; p; p = p->nxt)
	{	if (strcmp(p->n->name, X->n->name) == 0)
			continue;
		sprintf(buf, "P%s->", p->n->name);
		if (strstr((char *)tmp->cn, buf))
		{	printf("spin: in proctype %s, ref to object in proctype %s\n",
				X->n->name, p->n->name);
			fatal("invalid variable ref in '%s'", tmp->nm->name);
	}	}
}

void
plunk_expr(FILE *fd, char *s)
{	IType *tmp;

	tmp = find_inline(s);
	check_inline(tmp);

	fprintf(fd, "%s", (char *) tmp->cn);
}

void
preruse(FILE *fd, Lextok *n)	/* check a condition for c_expr with preconditions */
{	IType *tmp;

	if (!n) return;
	if (n->ntyp == C_EXPR)
	{	tmp = find_inline(n->sym->name);
		if (tmp->prec)
		{	fprintf(fd, "if (!(%s)) { if (!readtrail) { depth++; ", tmp->prec);
			fprintf(fd, "trpt++; trpt->pr = II; trpt->o_t = t;");
			fprintf(fd, "trpt->st = tt; Uerror(\"%s\"); } ", tmp->prec);
			fprintf(fd, "else { printf(\"pan: precondition false: %s\\n\"); ", tmp->prec);
			fprintf(fd, "_m = 3; goto P999; } } \n\t\t");
		}
	} else
	{	preruse(fd, n->rgt);
		preruse(fd, n->lft);
	}
}

int
glob_inline(char *s)
{	IType *tmp;
	char *bdy;

	tmp = find_inline(s);
	bdy = (char *) tmp->cn;
	return (strstr(bdy, "now.")		/* global ref or   */
	||      strchr(bdy, '(') > bdy);	/* possible C-function call */
}

void
plunk_inline(FILE *fd, char *s, int how)	/* c_code with precondition */
{	IType *tmp;

	tmp = find_inline(s);
	check_inline(tmp);

	fprintf(fd, "{ ");
	if (how && tmp->prec)
	{	fprintf(fd, "if (!(%s)) { if (!readtrail) { depth++; ", tmp->prec);
		fprintf(fd, "trpt++; trpt->pr = II; trpt->o_t = t;");
		fprintf(fd, "trpt->st = tt; Uerror(\"%s\"); } ", tmp->prec);
		fprintf(fd, "else { printf(\"pan: precondition false: %s\\n\"); ", tmp->prec);
		fprintf(fd, "_m = 3; goto P999; } } ");
	}
	fprintf(fd, "%s", (char *) tmp->cn);
	fprintf(fd, " }\n");
}

void
no_side_effects(char *s)
{	IType *tmp;
	char *t;

	/* could still defeat this check via hidden
	 * side effects in function calls,
	 * but this will catch at least some cases
	 */

	tmp = find_inline(s);
	t = (char *) tmp->cn;

	if (strchr(t, ';')
	||  strstr(t, "++")
	||  strstr(t, "--"))
	{
bad:		lineno = tmp->dln;
		Fname = tmp->dfn;
		non_fatal("c_expr %s has side-effects", s);
		return;
	}
	while ((t = strchr(t, '=')) != NULL)
	{	if (*(t-1) == '!'
		||  *(t-1) == '>'
		||  *(t-1) == '<')
		{	t++;
			continue;
		}
		t++;
		if (*t != '=')
			goto bad;
		t++;
	}
}

void
pickup_inline(Symbol *t, Lextok *apars)
{	IType *tmp; Lextok *p, *q; int j;

	tmp = find_inline(t->name);

	if (++Inlining >= MAXINL)
		fatal("inline fcts too deeply nested", 0);

	tmp->cln = lineno;	/* remember calling point */
	tmp->cfn = Fname;	/* and filename */

	for (p = apars, q = tmp->params, j = 0; p && q; p = p->rgt, q = q->rgt)
		j++; /* count them */
	if (p || q)
		fatal("wrong nr of params on call of '%s'", t->name);

	tmp->anms  = (char **) emalloc(j * sizeof(char *));
	for (p = apars, j = 0; p; p = p->rgt, j++)
	{	tmp->anms[j] = (char *) emalloc((int) strlen(IArg_cont[j])+1);
		strcpy(tmp->anms[j], IArg_cont[j]);
	}

	lineno = tmp->dln;	/* linenr of def */
	Fname = tmp->dfn;	/* filename of same */
	Inliner[Inlining] = (char *)tmp->cn;
	Inline_stub[Inlining] = tmp;
#if 0
	if (verbose&32)
	printf("spin: line %d, file %s, inlining '%s' (from line %d, file %s)\n",
		tmp->cln, tmp->cfn->name, t->name, tmp->dln, tmp->dfn->name);
#endif
	for (j = 0; j < Inlining; j++)
		if (Inline_stub[j] == Inline_stub[Inlining])
		fatal("cyclic inline attempt on: %s", t->name);
}

static void