tree.c

<B>Digital的Unix操作系统VAX 4.2源码</B>

/*@(#)tree.c	4.2	Ultrix	11/9/90*/

/************************************************************************
 *									*
 *			Copyright (c) 1985 by				*
 *		Digital Equipment Corporation, Maynard, MA		*
 *			All rights reserved.				*
 *									*
 *   This software is furnished under a license and may be used and	*
 *   copied  only  in accordance with the terms of such license and	*
 *   with the  inclusion  of  the  above  copyright  notice.   This	*
 *   software  or  any  other copies thereof may not be provided or	*
 *   otherwise made available to any other person.  No title to and	*
 *   ownership of the software is hereby transferred.			*
 *									*
 *   This software is  derived  from  software  received  from  the	*
 *   University    of   California,   Berkeley,   and   from   Bell	*
 *   Laboratories.  Use, duplication, or disclosure is  subject  to	*
 *   restrictions  under  license  agreements  with  University  of	*
 *   California and with AT&T.						*
 *									*
 *   The information in this software is subject to change  without	*
 *   notice  and should not be construed as a commitment by Digital	*
 *   Equipment Corporation.						*
 *									*
 *   Digital assumes no responsibility for the use  or  reliability	*
 *   of its software on equipment which is not supplied by Digital.	*
 *									*
 ************************************************************************/

/************************************************************************
 *									*
 *			Modification History				*
 *									*
 *  003	- Added support for vectors.							*
 *		  (L Miller, 18JAN90)									*
 *									*
 *	002 - Merged in 4.3 changes.					*
 *	      (vjh, April 29, 1986)					*
 *									*
 *	001 - Added support for O_PRINTENTRY node.			*
 *	      (Victoria Holt, July 22, 1985)				*
 *									*
 ************************************************************************/

/*
 * Copyright (c) 1983 Regents of the University of California.
 * All rights reserved.  The Berkeley software License Agreement
 * specifies the terms and conditions for redistribution.
 */

#ifndef lint
static char sccsid[] = "@(#)tree.c	5.1 (Berkeley) 5/31/85";
#endif not lint

static char rcsid[] = "$Header: tree.c,v 1.5 84/12/26 10:42:55 linton Exp $";

/*
 * Parse tree management.
 */

#include "defs.h"
#include "tree.h"
#include "operators.h"
#include "debug.h"
#include "eval.h"
#include "events.h"
#include "symbols.h"
#include "scanner.h"
#include "source.h"
#include "object.h"
#include "mappings.h"
#include "process.h"
#include "machine.h"

#ifndef public
#include "lists.h"

typedef struct Node *Node;
typedef Node Command;
typedef List Cmdlist;

#include "operators.h"
#include "symbols.h"
#include "events.h"

#define MAXNARGS 5

struct Node {
    Operator op;
    Symbol nodetype;
    union treevalue {
	Symbol sym;
	Name name;
	long lcon;
	double fcon;
	String scon;
	Node arg[MAXNARGS];
	struct {
	    Node cond;
	    Cmdlist actions;
	} event;
	struct {
	    Boolean inst;
	    Event event;
	    Cmdlist actions;
	} trace;
	struct {
	    Boolean source;
	    Boolean skipcalls;
	} step;
	struct {
	    String mode;
	    Node beginaddr;
	    Node endaddr;
	    Integer count;
	} examine;
	struct {
	    Node clist;
	    Language lang;
	} printform;
    } value;
};

#define evalcmd(cmd) eval(cmd)
#define cmdlist_append(cmd, cl) list_append(list_item(cmd), nil, cl)

#endif

typedef char *Arglist;

#define nextarg(type)  ((type *) (ap += sizeof(type)))[-1]

/*
 * Build a tree.
 */

/* VARARGS1 */
public Node build(op, args)
Operator op;
{
    register Node p, q;
    register Arglist ap;
    Integer i;

	p = new(Node);
    p->op = op;
    p->nodetype = nil;
    ap = (Arglist) &args;
    switch (op) {
	case O_NAME:
	    p->value.name = nextarg(Name);
	    break;

	case O_SYM:
	case O_PRINTCALL:
	case O_PRINTRTN:
	case O_PROCRTN:
	    p->value.sym = nextarg(Symbol);
	    break;

	case O_PRINTF:
	    p->value.printform.clist = nextarg(Node);
	    p->value.printform.lang = nextarg(Language);
	    break;

	case O_DEBUG:
	case O_LCON:
	case O_CCON:
	case O_CONT:
	case O_CATCH:
	case O_IGNORE:
	case O_TRACEOFF:
	    p->value.lcon = nextarg(long);
	    break;

	case O_FCON:
	    p->value.fcon = nextarg(double);
	    break;

	case O_SCON:
	case O_CHFILE:
	case O_EDIT:
	case O_SOURCE:
	case O_RECORD:
	    p->value.scon = nextarg(String);
	    break;

	case O_RVAL:
	case O_INDIR:
	    p->value.arg[0] = nextarg(Node);
	    break;
	
	case O_CALL:
	    q = nextarg(Node);
	    if (q->op == O_SYM and
		(q->value.sym->class == TYPE or q->value.sym->class == TAG)
	    ) {
		p->op = O_TYPERENAME;
		p->value.arg[0] = nextarg(Node);
		p->value.arg[1] = q;
		q = p->value.arg[0];
		if (q->value.arg[1] != nil) {
		    error("too many arguments to type rename");
		}
		p->value.arg[0] = q->value.arg[0];
	    } else {
		p->value.arg[0] = q;
		p->value.arg[1] = nextarg(Node);
	    }
	    break;

	case O_ADDEVENT:
	case O_ONCE:
	case O_IF:
	    p->value.event.cond = nextarg(Node);
	    p->value.event.actions = nextarg(Cmdlist);
	    break;

	case O_PRINTENTRY:
	case O_TRACEON:
	    p->value.trace.inst = nextarg(Boolean);
	    p->value.trace.event = nil;
	    p->value.trace.actions = nextarg(Cmdlist);
	    break;

	case O_STEP:
	case O_STEPV:
	    p->value.step.source = nextarg(Boolean);
	    p->value.step.skipcalls = nextarg(Boolean);
	    break;

	case O_EXAMINE:
	    p->value.examine.mode = nextarg(String);
	    p->value.examine.beginaddr = nextarg(Node);
	    p->value.examine.endaddr = nextarg(Node);
	    p->value.examine.count = nextarg(Integer);
	    break;

	case O_TMASK:
	case O_FMASK:
		p->value.arg[0] = nextarg(Node);
		p->value.arg[1] = nextarg(Node);
	    break;

	default:
	    for (i = 0; i < nargs(op); i++) {
		p->value.arg[i] = nextarg(Node);
	    }
	    break;
    }
    check(p);
    assigntypes(p);
    if (tracetree) {     
	printf("built %s node 0x%x with arg[0] 0x%x arg[1] 0x%x\n",
	    opname(p->op), p, p->value.arg[0], p->value.arg[1]);
	fflush(stdout);
    }
    return p;
}

/*
 * Strip away indirection from a node, thus returning a node for
 * interpreting the expression as an lvalue.
 */

public Node unrval (exp)
Node exp;
{
    Node p;

    if(exp->op == O_VREG and 
		((streq(ident(exp->nodetype->name), "$vmr")) ||
			(streq(ident(exp->nodetype->name), "$vcr")) ||
				(streq(ident(exp->nodetype->name), "$vaer")) ||
					(streq(ident(exp->nodetype->name), "$vlr")))) {
				error("illegal vector register syntax");
	}
    if(exp->op == O_SYM and isreg(exp->nodetype)) {
		error("illegal register syntax");
	}
	if (exp->op == O_RVAL) {
	p = exp->value.arg[0];
	dispose(exp);
    } else if (exp->op == O_INDIR) {
	p = exp->value.arg[0];
	if (p->op == O_RVAL) {
	    p->op = O_INDIR;
	    p->nodetype = exp->nodetype;
	}
	dispose(exp);
    } else {
	p = exp;
    }
    return p;
}

/*
 * Create a node for renaming a node to a pointer type.
 */

public Node renameptr (p, t)
Node p;
Node t;
{
    t->nodetype = newSymbol(nil, 0, PTR, t->nodetype, nil);
    p = build(O_TYPERENAME, p, t);
}

/*
 * Return the tree for a unary ampersand operator.
 */

public Node amper(p)
Node p;
{
    Node r;

    checkref(p);
    switch (p->op) {
	case O_RVAL:
	case O_INDIR:
	    if(p->nodetype == t_vquad)
	    {
	    	beginerrmsg();
	    	fprintf(stderr, "can not take address of \"");
	    	prtree(stderr, p);
	    	fprintf(stderr, "\"");
	    	enderrmsg();
	    }
	    else
	    {
	    	r = p->value.arg[0];
	    	r->nodetype = t_addr;
	    }
	    dispose(p);
	    break;

	case O_TYPERENAME:
	    r = p;
	    r->nodetype = newSymbol(nil, 0, PTR, r->nodetype, nil);
	    break;

	case O_SYM:
		if(isvreg(p->nodetype)) {
	    	beginerrmsg();
	    	fprintf(stderr, "can not take address of \"");
	    	prtree(stderr, p);
	    	fprintf(stderr, "\"");
	    	enderrmsg();
	    	/* NOTREACHED */
		}
		else
		{
	    	if (isroutine(p->value.sym)) {
				r = build(O_LCON, codeloc(p->value.sym));
	    	} else if (isblock(p->value.sym)) {
	    		beginerrmsg();
	    		fprintf(stderr, 
				   "can not take address of module or program, please qualify");
	    		enderrmsg();
	    	} else {
				r = build(O_LCON, address(p->value.sym, nil));
	    	}
	    	r->nodetype = t_addr;
		}
	    dispose(p);
	    break;

	case O_VREG:
	    beginerrmsg();
	    fprintf(stderr, "can not take address of \"");
	    prtree(stderr, p);
	    fprintf(stderr, "\"");
	    enderrmsg();
	    /* NOTREACHED */
	    break;

	case O_DOT:
	    r = p;
	    r->nodetype = t_addr;
	    break;

	default: