V7M/src/cmd/pcc/order.c
# include "mfile2"
int fltused = 0;
stoasg( p, o ) register NODE *p; {
/* should the assignment op p be stored,
given that it lies as the right operand of o
(or the left, if o==UNARY MUL) */
return( shltype(p->left->op, p->left ) );
}
deltest( p ) register NODE *p; {
/* should we delay the INCR or DECR operation p */
if( p->op == INCR && p->left->op == REG && spsz( p->left->type, p->right->lval ) ){
/* STARREG */
return( 0 );
}
p = p->left;
if( p->op == UNARY MUL ) p = p->left;
return( p->op == NAME || p->op == OREG || p->op == REG );
}
mkadrs(p) register NODE *p; {
register o;
o = p->op;
if( asgop(o) ){
if( p->left->su >= p->right->su ){
if( p->left->op == UNARY MUL ){
if( p->left->su > 0 )
SETSTO( p->left->left, INTEMP );
else {
if( p->right->su > 0 ) SETSTO( p->right, INTEMP );
else cerror( "store finds both sides trivial" );
}
}
else if( p->left->op == FLD && p->left->left->op == UNARY MUL ){
SETSTO( p->left->left->left, INTEMP );
}
else { /* should be only structure assignment */
SETSTO( p->left, INTEMP );
}
}
else SETSTO( p->right, INTEMP );
}
else {
if( p->left->su > p->right->su ){
SETSTO( p->left, INTEMP );
}
else {
SETSTO( p->right, INTEMP );
}
}
}
notoff( t, r, off, cp) TWORD t; CONSZ off; char *cp; {
/* is it legal to make an OREG or NAME entry which has an
/* offset of off, (from a register of r), if the
/* resulting thing had type t */
/* return( 1 ); /* NO */
return(0); /* YES */
}
# define max(x,y) ((x)<(y)?(y):(x))
# define min(x,y) ((x)<(y)?(x):(y))
# define ZCHAR 01
# define ZLONG 02
# define ZFLOAT 04
zum( p, zap ) register NODE *p; {
/* zap Sethi-Ullman number for chars, longs, floats */
/* in the case of longs, only STARNM's are zapped */
/* ZCHAR, ZLONG, ZFLOAT are used to select the zapping */
register su;
su = p->su;
switch( p->type ){
case CHAR:
case UCHAR:
if( !(zap&ZCHAR) ) break;
if( su == 0 ) p->su = su = 1;
break;
case LONG:
case ULONG:
if( !(zap&ZLONG) ) break;
if( p->op == UNARY MUL && su == 0 ) p->su = su = 2;
break;
case FLOAT:
if( !(zap&ZFLOAT) ) break;
if( su == 0 ) p->su = su = 1;
}
return( su );
}
sucomp( p ) register NODE *p; {
/* set the su field in the node to the sethi-ullman
number, or local equivalent */
register o, ty, sul, sur;
register nr;
ty = optype( o=p->op);
nr = szty( p->type );
p->su = 0;
if( ty == LTYPE ) {
if( p->type==FLOAT ) p->su = 1;
return;
}
else if( ty == UTYPE ){
switch( o ) {
case UNARY CALL:
case UNARY STCALL:
p->su = fregs; /* all regs needed */
return;
case UNARY MUL:
if( shumul( p->left ) ) return;
default:
p->su = max( p->left->su, nr);
return;
}
}
/* If rhs needs n, lhs needs m, regular su computation */
sul = p->left->su;
sur = p->right->su;
if( o == ASSIGN ){
asop: /* also used for +=, etc., to memory */
if( sul==0 ){
/* don't need to worry about the left side */
p->su = max( sur, nr );
}
else {
/* right, left address, op */
if( sur == 0 ){
/* just get the lhs address into a register, and mov */
/* the `nr' covers the case where value is in reg afterwards */
p->su = max( sul, nr );
}
else {
/* right, left address, op */
p->su = max( sur, nr+sul );
}
}
return;
}
if( o == CALL || o == STCALL ){
/* in effect, takes all free registers */
p->su = fregs;
return;
}
if( o == STASG ){
/* right, then left */
p->su = max( max( sul+nr, sur), fregs );
return;
}
if( logop(o) ){
/* do the harder side, then the easier side, into registers */
/* left then right, max(sul,sur+nr) */
/* right then left, max(sur,sul+nr) */
/* to hold both sides in regs: nr+nr */
nr = szty( p->left->type );
sul = zum( p->left, ZLONG|ZCHAR|ZFLOAT );
sur = zum( p->right, ZLONG|ZCHAR|ZFLOAT );
p->su = min( max(sul,sur+nr), max(sur,sul+nr) );
return;
}
if( asgop(o) ){
/* computed by doing right, doing left address, doing left, op, and store */
switch( o ) {
case INCR:
case DECR:
/* do as binary op */
break;
case ASG DIV:
case ASG MOD:
case ASG MUL:
if( p->type!=FLOAT && p->type!=DOUBLE ) nr = fregs;
goto gencase;
case ASG PLUS:
case ASG MINUS:
case ASG AND: /* really bic */
case ASG OR:
if( p->type == INT || p->type == UNSIGNED || ISPTR(p->type) ) goto asop;
gencase:
default:
sur = zum( p->right, ZCHAR|ZLONG|ZFLOAT );
if( sur == 0 ){ /* easy case: if addressable,
do left value, op, store */
if( sul == 0 ) p->su = nr;
/* harder: left adr, val, op, store */
else p->su = max( sul, nr+1 );
}
else { /* do right, left adr, left value, op, store */
if( sul == 0 ){ /* right, left value, op, store */
p->su = max( sur, nr+nr );
}
else {
p->su = max( sur, max( sul+nr, 1+nr+nr ) );
}
}
return;
}
}
switch( o ){
case ANDAND:
case OROR:
case QUEST:
case COLON:
case COMOP:
p->su = max( max(sul,sur), nr);
return;
}
if( ( o==DIV || o==MOD || o==MUL )
&& p->type!=FLOAT && p->type!=DOUBLE ) nr = fregs;
if( o==PLUS || o==MUL || o==OR || o==ER ){
/* AND is ruined by the hardware */
/* permute: get the harder on the left */
register rt, lt;
if( istnode( p->left ) || sul > sur ) goto noswap; /* don't do it! */
/* look for a funny type on the left, one on the right */
lt = p->left->type;
rt = p->right->type;
if( rt == FLOAT && lt == DOUBLE ) goto swap;
if( (rt==CHAR||rt==UCHAR) && (lt==INT||lt==UNSIGNED||ISPTR(lt)) ) goto swap;
if( lt==LONG || lt==ULONG ){
if( rt==LONG || rt==ULONG ){
/* if one is a STARNM, swap */
if( p->left->op == UNARY MUL && sul==0 ) goto noswap;
if( p->right->op == UNARY MUL && p->left->op != UNARY MUL ) goto swap;
goto noswap;
}
else if( p->left->op == UNARY MUL && sul == 0 ) goto noswap;
else goto swap; /* put long on right, unless STARNM */
}
/* we are finished with the type stuff now; if one is addressable,
put it on the right */
if( sul == 0 && sur != 0 ){
NODE *s;
int ssu;
swap:
ssu = sul; sul = sur; sur = ssu;
s = p->left; p->left = p->right; p->right = s;
}
}
noswap:
sur = zum( p->right, ZCHAR|ZLONG|ZFLOAT );
if( sur == 0 ){
/* get left value into a register, do op */
p->su = max( nr, sul );
}
else {
/* do harder into a register, then easier */
p->su = max( nr+nr, min( max( sul, nr+sur ), max( sur, nr+sul ) ) );
}
}
int radebug = 0;
mkrall( p, r ) register NODE *p; {
/* insure that the use of p gets done with register r; in effect, */
/* simulate offstar */
if( p->op == FLD ){
p->left->rall = p->rall;
p = p->left;
}
if( p->op != UNARY MUL ) return; /* no more to do */
p = p->left;
if( p->op == UNARY MUL ){
p->rall = r;
p = p->left;
}
if( p->op == PLUS && p->right->op == ICON ){
p->rall = r;
p = p->left;
}
rallo( p, r );
}
rallo( p, down ) register NODE *p; {
/* do register allocation */
register o, type, down1, down2, ty;
if( radebug ) printf( "rallo( %o, %o )\n", p, down );
down2 = NOPREF;
p->rall = down;
down1 = ( down &= ~MUSTDO );
ty = optype( o = p->op );
type = p->type;
if( type == DOUBLE || type == FLOAT ){
if( o == FORCE ) down1 = FR0|MUSTDO;
++fltused;
}
else switch( o ) {
case ASSIGN:
down1 = NOPREF;
down2 = down;
break;
case ASG MUL:
case ASG DIV:
case ASG MOD:
/* keep the addresses out of the hair of (r0,r1) */
if(fregs == 2 ){
/* lhs in (r0,r1), nothing else matters */
down1 = R1|MUSTDO;
down2 = NOPREF;
break;
}
/* at least 3 regs free */
/* compute lhs in (r0,r1), address of left in r2 */
p->left->rall = R1|MUSTDO;
mkrall( p->left, R2|MUSTDO );
/* now, deal with right */
if( fregs == 3 ) rallo( p->right, NOPREF );
else {
/* put address of long or value here */
p->right->rall = R3|MUSTDO;
mkrall( p->right, R3|MUSTDO );
}
return;
case MUL:
case DIV:
case MOD:
rallo( p->left, R1|MUSTDO );
if( fregs == 2 ){
rallo( p->right, NOPREF );
return;
}
/* compute addresses, stay away from (r0,r1) */
p->right->rall = (fregs==3) ? R2|MUSTDO : R3|MUSTDO ;
mkrall( p->right, R2|MUSTDO );
return;
case CALL:
case STASG:
case EQ:
case NE:
case GT:
case GE:
case LT:
case LE:
case NOT:
case ANDAND:
case OROR:
down1 = NOPREF;
break;
case FORCE:
down1 = R0|MUSTDO;
break;
}
if( ty != LTYPE ) rallo( p->left, down1 );
if( ty == BITYPE ) rallo( p->right, down2 );
}
offstar( p ) register NODE *p; {
/* handle indirections */
if( p->op == UNARY MUL ) p = p->left;
if( p->op == PLUS || p->op == MINUS ){
if( p->right->op == ICON ){
order( p->left , INTAREG|INAREG );
return;
}
}
order( p, INTAREG|INAREG );
}
setincr( p ) NODE *p; {
return( 0 ); /* for the moment, don't bother */
}
niceuty( p ) register NODE *p; {
register TWORD t;
return( p->op == UNARY MUL && (t=p->type)!=CHAR &&
t!= UCHAR && t!= FLOAT &&
shumul( p->left) != STARREG );
}
setbin( p ) register NODE *p; {
register NODE *r, *l;
r = p->right;
l = p->left;
if( p->right->su == 0 ){ /* rhs is addressable */
if( logop( p->op ) ){
if( l->op == UNARY MUL && l->type != FLOAT && shumul( l->left ) != STARREG ) offstar( l->left );
else order( l, INAREG|INTAREG|INBREG|INTBREG|INTEMP );
return( 1 );
}
if( !istnode( l ) ){
order( l, INTAREG|INTBREG );
return( 1 );
}
/* rewrite */
return( 0 );
}
/* now, rhs is complicated: must do both sides into registers */
/* do the harder side first */
if( logop( p->op ) ){
/* relational: do both sides into regs if need be */
if( r->su > l->su ){
if( niceuty(r) ){
offstar( r->left );
return( 1 );
}
else if( !istnode( r ) ){
order( r, INTAREG|INAREG|INTBREG|INBREG|INTEMP );
return( 1 );
}
}
if( niceuty(l) ){
offstar( l->left );
return( 1 );
}
else if( niceuty(r) ){
offstar( r->left );
return( 1 );
}
else if( !istnode( l ) ){
order( l, INTAREG|INAREG|INTBREG|INBREG|INTEMP );
return( 1 );
}
if( !istnode( r ) ){
order( r, INTAREG|INAREG|INTBREG|INBREG|INTEMP );
return( 1 );
}
cerror( "setbin can't deal with %s", opst[p->op] );
}
/* ordinary operator */
if( !istnode(r) && r->su > l->su ){
/* if there is a chance of making it addressable, try it... */
if( niceuty(r) ){
offstar( r->left );
return( 1 ); /* hopefully, it is addressable by now */
}
order( r, INTAREG|INAREG|INTBREG|INBREG|INTEMP ); /* anything goes on rhs */
return( 1 );
}
else {
if( !istnode( l ) ){
order( l, INTAREG|INTBREG );
return( 1 );
}
/* rewrite */
return( 0 );
}
}
setstr( p ) register NODE *p; { /* structure assignment */
if( p->right->op != REG ){
order( p->right, INTAREG );
return(1);
}
p = p->left;
if( p->op != NAME && p->op != OREG ){
if( p->op != UNARY MUL ) cerror( "bad setstr" );
order( p->left, INTAREG );
return( 1 );
}
return( 0 );
}
setasg( p ) register NODE *p; {
/* setup for assignment operator */
if( p->right->su != 0 && p->right->op != REG ) {
if( p->right->op == UNARY MUL )
offstar( p->right->left );
else
order( p->right, INAREG|INBREG|SOREG|SNAME|SCON );
return(1);
}
if( p->right->op != REG && ( p->type == FLOAT || p->type == DOUBLE ) ) {
order( p->right, INBREG );
return(1);
}
if( p->left->op == UNARY MUL && !tshape( p->left, STARREG|STARNM ) ){
offstar( p->left->left );
return(1);
}
if( p->left->op == FLD && p->left->left->op == UNARY MUL ){
offstar( p->left->left->left );
return(1);
}
/* if things are really strange, get rhs into a register */
if( p->right->op != REG ){
order( p->right, INAREG|INBREG );
return( 1 );
}
return(0);
}
setasop( p ) register NODE *p; {
/* setup for =ops */
register sul, sur;
register NODE *q, *p2;
sul = p->left->su;
sur = p->right->su;
switch( p->op ){
case ASG PLUS:
case ASG OR:
case ASG MINUS:
if( p->type != INT && p->type != UNSIGNED && !ISPTR(p->type) ) break;
if( p->right->type == CHAR || p->right->type == UCHAR ){
order( p->right, INAREG );
return( 1 );
}
break;
case ASG ER:
if( sul == 0 || p->left->op == REG ){
if( p->left->type == CHAR || p->left->type == UCHAR ) goto rew; /* rewrite */
order( p->right, INAREG|INBREG );
return( 1 );
}
goto leftadr;
}
if( sur == 0 ){
leftadr:
/* easy case: if addressable, do left value, op, store */
if( sul == 0 ) goto rew; /* rewrite */
/* harder; make aleft address, val, op, and store */
if( p->left->op == UNARY MUL ){
offstar( p->left->left );
return( 1 );
}
if( p->left->op == FLD && p->left->left->op == UNARY MUL ){
offstar( p->left->left->left );
return( 1 );
}
rew: /* rewrite, accounting for autoincrement and autodecrement */
q = p->left;
if( q->op == FLD ) q = q->left;
if( q->op != UNARY MUL || shumul(q->left) != STARREG ) return(0); /* let reader.c do it */
/* mimic code from reader.c */
p2 = tcopy( p );
p->op = ASSIGN;
reclaim( p->right, RNULL, 0 );
p->right = p2;
/* now, zap INCR on right, ASG MINUS on left */
if( q->left->op == INCR ){
q = p2->left;
if( q->op == FLD ) q = q->left;
if( q->left->op != INCR ) cerror( "bad incr rewrite" );
}
else if( q->left->op != ASG MINUS ) cerror( " bad -= rewrite" );
q->left->right->op = FREE;
q->left->op = FREE;
q->left = q->left->left;
/* now, resume reader.c rewriting code */
canon(p);
rallo( p, p->rall );
order( p2->left, INTBREG|INTAREG );
order( p2, INTBREG|INTAREG );
return( 1 );
}
/* harder case: do right, left address, left value, op, store */
if( p->right->op == UNARY MUL ){
offstar( p->right->left );
return( 1 );
}
/* sur> 0, since otherwise, done above */
if( p->right->op == REG ) goto leftadr; /* make lhs addressable */
order( p->right, INAREG|INBREG );
return( 1 );
}
int crslab = 10000;
getlab(){
return( crslab++ );
}
deflab( l ){
printf( "L%d:\n", l );
}
genargs( p) register NODE *p; {
register size;
/* generate code for the arguments */
/* first, do the arguments on the right (last->first) */
while( p->op == CM ){
genargs( p->right );
p->op = FREE;
p = p->left;
}
if( p->op == STARG ){ /* structure valued argument */
size = p->stsize;
if( p->left->op == ICON ){
/* make into a name node */
p->op = FREE;
p= p->left;
p->op = NAME;
}
else {
/* make it look beautiful... */
p->op = UNARY MUL;
canon( p ); /* turn it into an oreg */
if( p->op != OREG ){
offstar( p->left );
canon( p );
if( p->op != OREG ) cerror( "stuck starg" );
}
}
p->lval += size; /* end of structure */
/* put on stack backwards */
for( ; size>0; size -= 2 ){
p->lval -= 2;
expand( p, RNOP, " mov AR,Z-\n" );
}
reclaim( p, RNULL, 0 );
return;
}
/* ordinary case */
order( p, FORARG );
}
argsize( p ) register NODE *p; {
register t;
t = 0;
if( p->op == CM ){
t = argsize( p->left );
p = p->right;
}
if( p->type == DOUBLE || p->type == FLOAT ){
SETOFF( t, 2 );
return( t+8 );
}
else if( p->type == LONG || p->type == ULONG ) {
SETOFF( t, 2);
return( t+4 );
}
else if( p->op == STARG ){
SETOFF( t, p->stalign ); /* alignment */
return( t + p->stsize ); /* size */
}
else {
SETOFF( t, 2 );
return( t+2 );
}
}