cmd.c

早期freebsd实现

/* $RCSfile: cmd.c,v $$Revision: 4.0.1.5 $$Date: 92/06/08 12:00:39 $
 *
 *    Copyright (c) 1991, Larry Wall
 *
 *    You may distribute under the terms of either the GNU General Public
 *    License or the Artistic License, as specified in the README file.
 *
 * $Log:	cmd.c,v $
 * Revision 4.0.1.5  92/06/08  12:00:39  lwall
 * patch20: the switch optimizer didn't do anything in subroutines
 * patch20: removed implicit int declarations on funcions
 * 
 * Revision 4.0.1.4  91/11/11  16:29:33  lwall
 * patch19: do {$foo ne "bar";} returned wrong value
 * patch19: some earlier patches weren't propagated to alternate 286 code
 * 
 * Revision 4.0.1.3  91/11/05  16:07:43  lwall
 * patch11: random cleanup
 * patch11: "foo\0" eq "foo" was sometimes optimized to true
 * patch11: foreach on null list could spring memory leak
 * 
 * Revision 4.0.1.2  91/06/07  10:26:45  lwall
 * patch4: new copyright notice
 * patch4: made some allowances for "semi-standard" C
 * 
 * Revision 4.0.1.1  91/04/11  17:36:16  lwall
 * patch1: you may now use "die" and "caller" in a signal handler
 * 
 * Revision 4.0  91/03/20  01:04:18  lwall
 * 4.0 baseline.
 * 
 */

#include "EXTERN.h"
#include "perl.h"

#ifdef I_VARARGS
#  include <varargs.h>
#endif

static STR strchop;

void grow_dlevel();

/* do longjmps() clobber register variables? */

#if defined(cray) || defined(STANDARD_C)
#define JMPCLOBBER
#endif

/* This is the main command loop.  We try to spend as much time in this loop
 * as possible, so lots of optimizations do their activities in here.  This
 * means things get a little sloppy.
 */

int
cmd_exec(cmdparm,gimme,sp)
CMD *VOLATILE cmdparm;
VOLATILE int gimme;
VOLATILE int sp;
{
    register CMD *cmd = cmdparm;
    SPAT *VOLATILE oldspat;
    VOLATILE int firstsave = savestack->ary_fill;
    VOLATILE int oldsave;
    VOLATILE int aryoptsave;
#ifdef DEBUGGING
    VOLATILE int olddlevel;
    VOLATILE int entdlevel;
#endif
    register STR *retstr = &str_undef;
    register char *tmps;
    register int cmdflags;
    register int match;
    register char *go_to = goto_targ;
    register int newsp = -2;
    register STR **st = stack->ary_array;
    FILE *VOLATILE fp;
    ARRAY *VOLATILE ar;

    lastsize = 0;
#ifdef DEBUGGING
    entdlevel = dlevel;
#endif
tail_recursion_entry:
#ifdef DEBUGGING
    dlevel = entdlevel;
    if (debug & 4)
	deb("mortals = (%d/%d) stack, = (%d/%d)\n",
	    tmps_max, tmps_base,
	    savestack->ary_fill, firstsave);
#endif
#ifdef TAINT
    tainted = 0;	/* Each statement is presumed innocent */
#endif
    if (cmd == Nullcmd) {
	if (gimme == G_ARRAY && newsp > -2)
	    return newsp;
	else {
	    st[++sp] = retstr;
	    return sp;
	}
    }
    cmdflags = cmd->c_flags;	/* hopefully load register */
    if (go_to) {
	if (cmd->c_label && strEQ(go_to,cmd->c_label))
	    goto_targ = go_to = Nullch;		/* here at last */
	else {
	    switch (cmd->c_type) {
	    case C_IF:
		oldspat = curspat;
		oldsave = savestack->ary_fill;
#ifdef DEBUGGING
		olddlevel = dlevel;
#endif
		retstr = &str_yes;
		newsp = -2;
		if (cmd->ucmd.ccmd.cc_true) {
#ifdef DEBUGGING
		    if (debug) {
			debname[dlevel] = 't';
			debdelim[dlevel] = '_';
			if (++dlevel >= dlmax)
			    grow_dlevel();
		    }
#endif
		    newsp = cmd_exec(cmd->ucmd.ccmd.cc_true,gimme && (cmdflags & CF_TERM),sp);
		    st = stack->ary_array;	/* possibly reallocated */
		    retstr = st[newsp];
		}
		if (!goto_targ)
		    go_to = Nullch;
		curspat = oldspat;
		if (savestack->ary_fill > oldsave)
		    restorelist(oldsave);
#ifdef DEBUGGING
		dlevel = olddlevel;
#endif
		cmd = cmd->ucmd.ccmd.cc_alt;
		goto tail_recursion_entry;
	    case C_ELSE:
		oldspat = curspat;
		oldsave = savestack->ary_fill;
#ifdef DEBUGGING
		olddlevel = dlevel;
#endif
		retstr = &str_undef;
		newsp = -2;
		if (cmd->ucmd.ccmd.cc_true) {
#ifdef DEBUGGING
		    if (debug) {
			debname[dlevel] = 'e';
			debdelim[dlevel] = '_';
			if (++dlevel >= dlmax)
			    grow_dlevel();
		    }
#endif
		    newsp = cmd_exec(cmd->ucmd.ccmd.cc_true,gimme && (cmdflags & CF_TERM),sp);
		    st = stack->ary_array;	/* possibly reallocated */
		    retstr = st[newsp];
		}
		if (!goto_targ)
		    go_to = Nullch;
		curspat = oldspat;
		if (savestack->ary_fill > oldsave)
		    restorelist(oldsave);
#ifdef DEBUGGING
		dlevel = olddlevel;
#endif
		break;
	    case C_BLOCK:
	    case C_WHILE:
		if (!(cmdflags & CF_ONCE)) {
		    cmdflags |= CF_ONCE;
		    if (++loop_ptr >= loop_max) {
			loop_max += 128;
			Renew(loop_stack, loop_max, struct loop);
		    }
		    loop_stack[loop_ptr].loop_label = cmd->c_label;
		    loop_stack[loop_ptr].loop_sp = sp;
#ifdef DEBUGGING
		    if (debug & 4) {
			deb("(Pushing label #%d %s)\n",
			  loop_ptr, cmd->c_label ? cmd->c_label : "");
		    }
#endif
		}
#ifdef JMPCLOBBER
		cmdparm = cmd;
#endif
		match = setjmp(loop_stack[loop_ptr].loop_env);
		if (match) {
		    st = stack->ary_array;	/* possibly reallocated */
#ifdef JMPCLOBBER
		    cmd = cmdparm;
		    cmdflags = cmd->c_flags|CF_ONCE;
#endif
		    if (savestack->ary_fill > oldsave)
			restorelist(oldsave);
		    switch (match) {
		    default:
			fatal("longjmp returned bad value (%d)",match);
		    case O_LAST:	/* not done unless go_to found */
			go_to = Nullch;
			if (lastretstr) {
			    retstr = lastretstr;
			    newsp = -2;
			}
			else {
			    newsp = sp + lastsize;
			    retstr = st[newsp];
			}
#ifdef DEBUGGING
			olddlevel = dlevel;
#endif
			curspat = oldspat;
			goto next_cmd;
		    case O_NEXT:	/* not done unless go_to found */
			go_to = Nullch;
#ifdef JMPCLOBBER
			newsp = -2;
			retstr = &str_undef;
#endif
			goto next_iter;
		    case O_REDO:	/* not done unless go_to found */
			go_to = Nullch;
#ifdef JMPCLOBBER
			newsp = -2;
			retstr = &str_undef;
#endif
			goto doit;
		    }
		}
		oldspat = curspat;
		oldsave = savestack->ary_fill;
#ifdef DEBUGGING
		olddlevel = dlevel;
#endif
		if (cmd->ucmd.ccmd.cc_true) {
#ifdef DEBUGGING
		    if (debug) {
			debname[dlevel] = 't';
			debdelim[dlevel] = '_';
			if (++dlevel >= dlmax)
			    grow_dlevel();
		    }
#endif
		    newsp = cmd_exec(cmd->ucmd.ccmd.cc_true,gimme && (cmdflags & CF_TERM),sp);
		    st = stack->ary_array;	/* possibly reallocated */
		    if (newsp >= 0)
			retstr = st[newsp];
		}
		if (!goto_targ) {
		    go_to = Nullch;
		    goto next_iter;
		}
#ifdef DEBUGGING
		dlevel = olddlevel;
#endif
		if (cmd->ucmd.ccmd.cc_alt) {
#ifdef DEBUGGING
		    if (debug) {
			debname[dlevel] = 'a';
			debdelim[dlevel] = '_';
			if (++dlevel >= dlmax)
			    grow_dlevel();
		    }
#endif
		    newsp = cmd_exec(cmd->ucmd.ccmd.cc_alt,gimme && (cmdflags & CF_TERM),sp);
		    st = stack->ary_array;	/* possibly reallocated */
		    if (newsp >= 0)
			retstr = st[newsp];
		}
		if (goto_targ)
		    break;
		go_to = Nullch;
		goto finish_while;
	    }
	    cmd = cmd->c_next;
	    if (cmd && cmd->c_head == cmd)
					/* reached end of while loop */
		return sp;		/* targ isn't in this block */
	    if (cmdflags & CF_ONCE) {
#ifdef DEBUGGING
		if (debug & 4) {
		    tmps = loop_stack[loop_ptr].loop_label;
		    deb("(Popping label #%d %s)\n",loop_ptr,
			tmps ? tmps : "" );
		}
#endif
		loop_ptr--;
	    }
	    goto tail_recursion_entry;
	}
    }

until_loop:

    /* Set line number so run-time errors can be located */

    curcmd = cmd;

#ifdef DEBUGGING
    if (debug) {
	if (debug & 2) {
	    deb("%s	(%lx)	r%lx	t%lx	a%lx	n%lx	cs%lx\n",
		cmdname[cmd->c_type],cmd,cmd->c_expr,
		cmd->ucmd.ccmd.cc_true,cmd->ucmd.ccmd.cc_alt,cmd->c_next,
		curspat);
	}
	debname[dlevel] = cmdname[cmd->c_type][0];
	debdelim[dlevel] = '!';
	if (++dlevel >= dlmax)
	    grow_dlevel();
    }
#endif

    /* Here is some common optimization */

    if (cmdflags & CF_COND) {
	switch (cmdflags & CF_OPTIMIZE) {

	case CFT_FALSE:
	    retstr = cmd->c_short;
	    newsp = -2;
	    match = FALSE;
	    if (cmdflags & CF_NESURE)
		goto maybe;
	    break;
	case CFT_TRUE:
	    retstr = cmd->c_short;
	    newsp = -2;
	    match = TRUE;
	    if (cmdflags & CF_EQSURE)
		goto flipmaybe;
	    break;

	case CFT_REG:
	    retstr = STAB_STR(cmd->c_stab);
	    newsp = -2;
	    match = str_true(retstr);	/* => retstr = retstr, c2 should fix */
	    if (cmdflags & (match ? CF_EQSURE : CF_NESURE))
		goto flipmaybe;
	    break;

	case CFT_ANCHOR:	/* /^pat/ optimization */
	    if (multiline) {
		if (*cmd->c_short->str_ptr && !(cmdflags & CF_EQSURE))
		    goto scanner;	/* just unanchor it */
		else
		    break;		/* must evaluate */
	    }
	    match = 0;
	    goto strop;

	case CFT_STROP:		/* string op optimization */
	    match = 1;
	  strop:
	    retstr = STAB_STR(cmd->c_stab);
	    newsp = -2;
#ifndef I286
	    if (*cmd->c_short->str_ptr == *str_get(retstr) &&
		    (match ? retstr->str_cur == cmd->c_slen - 1 :
		    	     retstr->str_cur >= cmd->c_slen) &&
		    bcmp(cmd->c_short->str_ptr, str_get(retstr),
		      cmd->c_slen) == 0 ) {
		if (cmdflags & CF_EQSURE) {
		    if (sawampersand && (cmdflags & CF_OPTIMIZE) != CFT_STROP) {
			curspat = Nullspat;
			if (leftstab)
			    str_nset(stab_val(leftstab),"",0);
			if (amperstab)
			    str_sset(stab_val(amperstab),cmd->c_short);
			if (rightstab)
			    str_nset(stab_val(rightstab),
			      retstr->str_ptr + cmd->c_slen,
			      retstr->str_cur - cmd->c_slen);
		    }
		    if (cmd->c_spat)
			lastspat = cmd->c_spat;
		    match = !(cmdflags & CF_FIRSTNEG);
		    retstr = match ? &str_yes : &str_no;
		    goto flipmaybe;
		}
	    }
	    else if (cmdflags & CF_NESURE) {
		match = cmdflags & CF_FIRSTNEG;
		retstr = match ? &str_yes : &str_no;
		goto flipmaybe;
	    }
#else
	    {
		char *zap1, *zap2, zap1c, zap2c;
		int  zaplen;
		int lenok;

		zap1 = cmd->c_short->str_ptr;
		zap2 = str_get(retstr);
		zap1c = *zap1;
		zap2c = *zap2;
		zaplen = cmd->c_slen;
		if (match)
		    lenok = (retstr->str_cur == cmd->c_slen - 1);
		else
		    lenok = (retstr->str_cur >= cmd->c_slen);
		if ((zap1c == zap2c) && lenok && (bcmp(zap1, zap2, zaplen) == 0)) {
		    if (cmdflags & CF_EQSURE) {
			if (sawampersand &&
			  (cmdflags & CF_OPTIMIZE) != CFT_STROP) {
			    curspat = Nullspat;
			    if (leftstab)
				str_nset(stab_val(leftstab),"",0);
			    if (amperstab)
				str_sset(stab_val(amperstab),cmd->c_short);
			    if (rightstab)
				str_nset(stab_val(rightstab),
					 retstr->str_ptr + cmd->c_slen,
					 retstr->str_cur - cmd->c_slen);
			}
			if (cmd->c_spat)
			    lastspat = cmd->c_spat;
		 	match = !(cmdflags & CF_FIRSTNEG);
			retstr = match ? &str_yes : &str_no;
		 	goto flipmaybe;
		    }
		}
		else if (cmdflags & CF_NESURE) {
		    match = cmdflags & CF_FIRSTNEG;
		    retstr = match ? &str_yes : &str_no;
		    goto flipmaybe;
		}
	    }
#endif
	    break;			/* must evaluate */

	case CFT_SCAN:			/* non-anchored search */
	  scanner:
	    retstr = STAB_STR(cmd->c_stab);
	    newsp = -2;
	    if (retstr->str_pok & SP_STUDIED)
		if (screamfirst[cmd->c_short->str_rare] >= 0)
		    tmps = screaminstr(retstr, cmd->c_short);
		else
		    tmps = Nullch;
	    else {
		tmps = str_get(retstr);		/* make sure it's pok */
#ifndef lint
		tmps = fbminstr((unsigned char*)tmps,
		    (unsigned char*)tmps + retstr->str_cur, cmd->c_short);
#endif
	    }
	    if (tmps) {
		if (cmdflags & CF_EQSURE) {
		    ++cmd->c_short->str_u.str_useful;
		    if (sawampersand) {
			curspat = Nullspat;
			if (leftstab)
			    str_nset(stab_val(leftstab),retstr->str_ptr,
			      tmps - retstr->str_ptr);
			if (amperstab)
			    str_nset(stab_val(amperstab),
			      tmps, cmd->c_short->str_cur);
			if (rightstab)
			    str_nset(stab_val(rightstab),
			      tmps + cmd->c_short->str_cur,
			      retstr->str_cur - (tmps - retstr->str_ptr) -
				cmd->c_short->str_cur);
		    }
		    lastspat = cmd->c_spat;
		    match = !(cmdflags & CF_FIRSTNEG);
		    retstr = match ? &str_yes : &str_no;
		    goto flipmaybe;
		}
		else
		    hint = tmps;
	    }
	    else {
		if (cmdflags & CF_NESURE) {
		    ++cmd->c_short->str_u.str_useful;
		    match = cmdflags & CF_FIRSTNEG;
		    retstr = match ? &str_yes : &str_no;
		    goto flipmaybe;
		}
	    }
	    if (--cmd->c_short->str_u.str_useful < 0) {
		cmdflags &= ~CF_OPTIMIZE;
		cmdflags |= CFT_EVAL;	/* never try this optimization again */
		cmd->c_flags = (cmdflags & ~CF_ONCE);
	    }
	    break;			/* must evaluate */

	case CFT_NUMOP:		/* numeric op optimization */
	    retstr = STAB_STR(cmd->c_stab);
	    newsp = -2;
	    switch (cmd->c_slen) {
	    case O_EQ:
		if (dowarn) {
		    if ((!retstr->str_nok && !looks_like_number(retstr)))
			warn("Possible use of == on string value");
		}
		match = (str_gnum(retstr) == cmd->c_short->str_u.str_nval);
		break;
	    case O_NE:
		match = (str_gnum(retstr) != cmd->c_short->str_u.str_nval);
		break;
	    case O_LT:
		match = (str_gnum(retstr) <  cmd->c_short->str_u.str_nval);
		break;
	    case O_LE:
		match = (str_gnum(retstr) <= cmd->c_short->str_u.str_nval);
		break;
	    case O_GT:
		match = (str_gnum(retstr) >  cmd->c_short->str_u.str_nval);
		break;
	    case O_GE:
		match = (str_gnum(retstr) >= cmd->c_short->str_u.str_nval);
		break;
	    }
	    if (match) {
		if (cmdflags & CF_EQSURE) {
		    retstr = &str_yes;
		    goto flipmaybe;
		}
	    }
	    else if (cmdflags & CF_NESURE) {
		retstr = &str_no;
		goto flipmaybe;
	    }
	    break;			/* must evaluate */

	case CFT_INDGETS:		/* while (<$foo>) */
	    last_in_stab = stabent(str_get(STAB_STR(cmd->c_stab)),TRUE);
	    if (!stab_io(last_in_stab))
		stab_io(last_in_stab) = stio_new();
	    goto dogets;
	case CFT_GETS:			/* really a while (<file>) */
	    last_in_stab = cmd->c_stab;
	  dogets:
	    fp = stab_io(last_in_stab)->ifp;
	    retstr = stab_val(defstab);
	    newsp = -2;
	  keepgoing:
	    if (fp && str_gets(retstr, fp, 0)) {
		if (*retstr->str_ptr == '0' && retstr->str_cur == 1)
		    match = FALSE;
		else
		    match = TRUE;
		stab_io(last_in_stab)->lines++;
	    }
	    else if (stab_io(last_in_stab)->flags & IOF_ARGV) {
		if (!fp)
		    goto doeval;	/* first time through */
		fp = nextargv(last_in_stab);
		if (fp)
		    goto keepgoing;
		(void)do_close(last_in_stab,FALSE);
		stab_io(last_in_stab)->flags |= IOF_START;
		retstr = &str_undef;
		match = FALSE;
	    }
	    else {
		retstr = &str_undef;
		match = FALSE;
	    }
	    goto flipmaybe;
	case CFT_EVAL:
	    break;
	case CFT_UNFLIP:
	    while (tmps_max > tmps_base) {	/* clean up after last eval */
		str_free(tmps_list[tmps_max]);
		tmps_list[tmps_max--] = Nullstr;
	    }
	    newsp = eval(cmd->c_expr,gimme && (cmdflags & CF_TERM),sp);
	    st = stack->ary_array;	/* possibly reallocated */
	    retstr = st[newsp];
	    match = str_true(retstr);
	    if (cmd->c_expr->arg_type == O_FLIP)	/* undid itself? */
		cmdflags = copyopt(cmd,cmd->c_expr[3].arg_ptr.arg_cmd);
	    goto maybe;
	case CFT_CHOP:
	    retstr = stab_val(cmd->c_stab);
	    newsp = -2;
	    match = (retstr->str_cur != 0);
	    tmps = str_get(retstr);
	    tmps += retstr->str_cur - match;
	    str_nset(&strchop,tmps,match);
	    *tmps = '\0';
	    retstr->str_nok = 0;
	    retstr->str_cur = tmps - retstr->str_ptr;
	    STABSET(retstr);
	    retstr = &strchop;
	    goto flipmaybe;
	case CFT_ARRAY:
	    match = cmd->c_short->str_u.str_useful; /* just to get register */

	    if (match < 0) {		/* first time through here? */
		ar = stab_array(cmd->c_expr[1].arg_ptr.arg_stab);
		aryoptsave = savestack->ary_fill;
		savesptr(&stab_val(cmd->c_stab));
		savelong(&cmd->c_short->str_u.str_useful);
	    }
	    else {
		ar = stab_xarray(cmd->c_expr[1].arg_ptr.arg_stab);
		if (cmd->c_type != C_WHILE && savestack->ary_fill > firstsave)
		    restorelist(firstsave);
	    }

	    if (match >= ar->ary_fill) {	/* we're in LAST, probably */
		if (match < 0 &&		/* er, probably not... */
		  savestack->ary_fill > aryoptsave)
		    restorelist(aryoptsave);
		retstr = &str_undef;
		cmd->c_short->str_u.str_useful = -1;	/* actually redundant */
		match = FALSE;
	    }
	    else {
		match++;
		if (!(retstr = ar->ary_array[match]))
		    retstr = afetch(ar,match,TRUE);
		stab_val(cmd->c_stab) = retstr;
		cmd->c_short->str_u.str_useful = match;
		match = TRUE;
	    }
	    newsp = -2;
	    goto maybe;
	case CFT_D1:
	    break;
	case CFT_D0:
	    if (DBsingle->str_u.str_nval != 0)
		break;
	    if (DBsignal->str_u.str_nval != 0)