// Inferno utils/8c/reg.c
// http://code.google.com/p/inferno-os/source/browse/utils/8c/reg.c
//
// Copyright © 1994-1999 Lucent Technologies Inc. All rights reserved.
// Portions Copyright © 1995-1997 C H Forsyth (forsyth@terzarima.net)
// Portions Copyright © 1997-1999 Vita Nuova Limited
// Portions Copyright © 2000-2007 Vita Nuova Holdings Limited (www.vitanuova.com)
// Portions Copyright © 2004,2006 Bruce Ellis
// Portions Copyright © 2005-2007 C H Forsyth (forsyth@terzarima.net)
// Revisions Copyright © 2000-2007 Lucent Technologies Inc. and others
// Portions Copyright © 2009 The Go Authors. All rights reserved.
//
// Permission is hereby granted, free of charge, to any person obtaining a copy
// of this software and associated documentation files (the "Software"), to deal
// in the Software without restriction, including without limitation the rights
// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
// copies of the Software, and to permit persons to whom the Software is
// furnished to do so, subject to the following conditions:
//
// The above copyright notice and this permission notice shall be included in
// all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
// THE SOFTWARE.
#include "gc.h"
static void fixjmp(Reg*);
Reg*
rega(void)
{
Reg *r;
r = freer;
if(r == R) {
r = alloc(sizeof(*r));
} else
freer = r->link;
*r = zreg;
return r;
}
int
rcmp(const void *a1, const void *a2)
{
Rgn *p1, *p2;
int c1, c2;
p1 = (Rgn*)a1;
p2 = (Rgn*)a2;
c1 = p2->cost;
c2 = p1->cost;
if(c1 -= c2)
return c1;
return p2->varno - p1->varno;
}
void
regopt(Prog *p)
{
Reg *r, *r1, *r2;
Prog *p1;
int i, z;
int32 initpc, val, npc;
uint32 vreg;
Bits bit;
struct
{
int32 m;
int32 c;
Reg* p;
} log5[6], *lp;
firstr = R;
lastr = R;
nvar = 0;
regbits = RtoB(D_SP) | RtoB(D_AX);
for(z=0; z<BITS; z++) {
externs.b[z] = 0;
params.b[z] = 0;
consts.b[z] = 0;
addrs.b[z] = 0;
}
/*
* pass 1
* build aux data structure
* allocate pcs
* find use and set of variables
*/
val = 5L * 5L * 5L * 5L * 5L;
lp = log5;
for(i=0; i<5; i++) {
lp->m = val;
lp->c = 0;
lp->p = R;
val /= 5L;
lp++;
}
val = 0;
for(; p != P; p = p->link) {
switch(p->as) {
case ADATA:
case AGLOBL:
case ANAME:
case ASIGNAME:
case AFUNCDATA:
continue;
}
r = rega();
if(firstr == R) {
firstr = r;
lastr = r;
} else {
lastr->link = r;
r->p1 = lastr;
lastr->s1 = r;
lastr = r;
}
r->prog = p;
r->pc = val;
val++;
lp = log5;
for(i=0; i<5; i++) {
lp->c--;
if(lp->c <= 0) {
lp->c = lp->m;
if(lp->p != R)
lp->p->log5 = r;
lp->p = r;
(lp+1)->c = 0;
break;
}
lp++;
}
r1 = r->p1;
if(r1 != R)
switch(r1->prog->as) {
case ARET:
case AJMP:
case AIRETL:
r->p1 = R;
r1->s1 = R;
}
bit = mkvar(r, &p->from);
if(bany(&bit))
switch(p->as) {
/*
* funny
*/
case ALEAL:
for(z=0; z<BITS; z++)
addrs.b[z] |= bit.b[z];
break;
/*
* left side read
*/
default:
for(z=0; z<BITS; z++)
r->use1.b[z] |= bit.b[z];
break;
}
bit = mkvar(r, &p->to);
if(bany(&bit))
switch(p->as) {
default:
diag(Z, "reg: unknown op: %A", p->as);
break;
/*
* right side read
*/
case ACMPB:
case ACMPL:
case ACMPW:
case APREFETCHT0:
case APREFETCHT1:
case APREFETCHT2:
case APREFETCHNTA:
for(z=0; z<BITS; z++)
r->use2.b[z] |= bit.b[z];
break;
/*
* right side write
*/
case ANOP:
case AMOVL:
case AMOVB:
case AMOVW:
case AMOVBLSX:
case AMOVBLZX:
case AMOVWLSX:
case AMOVWLZX:
for(z=0; z<BITS; z++)
r->set.b[z] |= bit.b[z];
break;
/*
* right side read+write
*/
case AADDB:
case AADDL:
case AADDW:
case AANDB:
case AANDL:
case AANDW:
case ASUBB:
case ASUBL:
case ASUBW:
case AORB:
case AORL:
case AORW:
case AXORB:
case AXORL:
case AXORW:
case ASALB:
case ASALL:
case ASALW:
case ASARB:
case ASARL:
case ASARW:
case AROLB:
case AROLL:
case AROLW:
case ARORB:
case ARORL:
case ARORW:
case ASHLB:
case ASHLL:
case ASHLW:
case ASHRB:
case ASHRL:
case ASHRW:
case AIMULL:
case AIMULW:
case ANEGL:
case ANOTL:
case AADCL:
case ASBBL:
for(z=0; z<BITS; z++) {
r->set.b[z] |= bit.b[z];
r->use2.b[z] |= bit.b[z];
}
break;
/*
* funny
*/
case AFMOVDP:
case AFMOVFP:
case AFMOVLP:
case AFMOVVP:
case AFMOVWP:
case ACALL:
for(z=0; z<BITS; z++)
addrs.b[z] |= bit.b[z];
break;
}
switch(p->as) {
case AIMULL:
case AIMULW:
if(p->to.type != D_NONE)
break;
case AIDIVB:
case AIDIVL:
case AIDIVW:
case AIMULB:
case ADIVB:
case ADIVL:
case ADIVW:
case AMULB:
case AMULL:
case AMULW:
case ACWD:
case ACDQ:
r->regu |= RtoB(D_AX) | RtoB(D_DX);
break;
case AREP:
case AREPN:
case ALOOP:
case ALOOPEQ:
case ALOOPNE:
r->regu |= RtoB(D_CX);
break;
case AMOVSB:
case AMOVSL:
case AMOVSW:
case ACMPSB:
case ACMPSL:
case ACMPSW:
r->regu |= RtoB(D_SI) | RtoB(D_DI);
break;
case ASTOSB:
case ASTOSL:
case ASTOSW:
case ASCASB:
case ASCASL:
case ASCASW:
r->regu |= RtoB(D_AX) | RtoB(D_DI);
break;
case AINSB:
case AINSL:
case AINSW:
case AOUTSB:
case AOUTSL:
case AOUTSW:
r->regu |= RtoB(D_DI) | RtoB(D_DX);
break;
case AFSTSW:
case ASAHF:
r->regu |= RtoB(D_AX);
break;
}
}
if(firstr == R)
return;
initpc = pc - val;
npc = val;
/*
* pass 2
* turn branch references to pointers
* build back pointers
*/
for(r = firstr; r != R; r = r->link) {
p = r->prog;
if(p->to.type == D_BRANCH) {
val = p->to.offset - initpc;
r1 = firstr;
while(r1 != R) {
r2 = r1->log5;
if(r2 != R && val >= r2->pc) {
r1 = r2;
continue;
}
if(r1->pc == val)
break;
r1 = r1->link;
}
if(r1 == R) {
nearln = p->lineno;
diag(Z, "ref not found\n%P", p);
continue;
}
if(r1 == r) {
nearln = p->lineno;
diag(Z, "ref to self\n%P", p);
continue;
}
r->s2 = r1;
r->p2link = r1->p2;
r1->p2 = r;
}
}
if(debug['R']) {
p = firstr->prog;
print("\n%L %D\n", p->lineno, &p->from);
}
/*
* pass 2.1
* fix jumps
*/
fixjmp(firstr);
/*
* pass 2.5
* find looping structure
*/
for(r = firstr; r != R; r = r->link)
r->active = 0;
change = 0;
loopit(firstr, npc);
if(debug['R'] && debug['v']) {
print("\nlooping structure:\n");
for(r = firstr; r != R; r = r->link) {
print("%d:%P", r->loop, r->prog);
for(z=0; z<BITS; z++)
bit.b[z] = r->use1.b[z] |
r->use2.b[z] |
r->set.b[z];
if(bany(&bit)) {
print("\t");
if(bany(&r->use1))
print(" u1=%B", r->use1);
if(bany(&r->use2))
print(" u2=%B", r->use2);
if(bany(&r->set))
print(" st=%B", r->set);
}
print("\n");
}
}
/*
* pass 3
* iterate propagating usage
* back until flow graph is complete
*/
loop1:
change = 0;
for(r = firstr; r != R; r = r->link)
r->active = 0;
for(r = firstr; r != R; r = r->link)
if(r->prog->as == ARET)
prop(r, zbits, zbits);
loop11:
/* pick up unreachable code */
i = 0;
for(r = firstr; r != R; r = r1) {
r1 = r->link;
if(r1 && r1->active && !r->active) {
prop(r, zbits, zbits);
i = 1;
}
}
if(i)
goto loop11;
if(change)
goto loop1;
/*
* pass 4
* iterate propagating register/variable synchrony
* forward until graph is complete
*/
loop2:
change = 0;
for(r = firstr; r != R; r = r->link)
r->active = 0;
synch(firstr, zbits);
if(change)
goto loop2;
/*
* pass 5
* isolate regions
* calculate costs (paint1)
*/
r = firstr;
if(r) {
for(z=0; z<BITS; z++)
bit.b[z] = (r->refahead.b[z] | r->calahead.b[z]) &
~(externs.b[z] | params.b[z] | addrs.b[z] | consts.b[z]);
if(bany(&bit)) {
nearln = r->prog->lineno;
warn(Z, "used and not set: %B", bit);
if(debug['R'] && !debug['w'])
print("used and not set: %B\n", bit);
}
}
if(debug['R'] && debug['v'])
print("\nprop structure:\n");
for(r = firstr; r != R; r = r->link)
r->act = zbits;
rgp = region;
nregion = 0;
for(r = firstr; r != R; r = r->link) {
if(debug['R'] && debug['v']) {
print("%P\t", r->prog);
if(bany(&r->set))
print("s:%B ", r->set);
if(bany(&r->refahead))
print("ra:%B ", r->refahead);
if(bany(&r->calahead))
print("ca:%B ", r->calahead);
print("\n");
}
for(z=0; z<BITS; z++)
bit.b[z] = r->set.b[z] &
~(r->refahead.b[z] | r->calahead.b[z] | addrs.b[z]);
if(bany(&bit)) {
nearln = r->prog->lineno;
warn(Z, "set and not used: %B", bit);
if(debug['R'])
print("set and not used: %B\n", bit);
excise(r);
}
for(z=0; z<BITS; z++)
bit.b[z] = LOAD(r) & ~(r->act.b[z] | addrs.b[z]);
while(bany(&bit)) {
i = bnum(bit);
rgp->enter = r;
rgp->varno = i;
change = 0;
if(debug['R'] && debug['v'])
print("\n");
paint1(r, i);
bit.b[i/32] &= ~(1L<<(i%32));
if(change <= 0) {
if(debug['R'])
print("%L$%d: %B\n",
r->prog->lineno, change, blsh(i));
continue;
}
rgp->cost = change;
nregion++;
if(nregion >= NRGN) {
warn(Z, "too many regions");
goto brk;
}
rgp++;
}
}
brk:
qsort(region, nregion, sizeof(region[0]), rcmp);
/*
* pass 6
* determine used registers (paint2)
* replace code (paint3)
*/
rgp = region;
for(i=0; i<nregion; i++) {
bit = blsh(rgp->varno);
vreg = paint2(rgp->enter, rgp->varno);
vreg = allreg(vreg, rgp);
if(debug['R']) {
print("%L$%d %R: %B\n",
rgp->enter->prog->lineno,
rgp->cost,
rgp->regno,
bit);
}
if(rgp->regno != 0)
paint3(rgp->enter, rgp->varno, vreg, rgp->regno);
rgp++;
}
/*
* pass 7
* peep-hole on basic block
*/
if(!debug['R'] || debug['P'])
peep();
if(debug['R'] && debug['v']) {
print("after pass 7 (peep)\n");
for(r=firstr; r; r=r->link)
print("%04d %P\n", (int)r->pc, r->prog);
print("\n");
}
/*
* pass 8
* recalculate pc
*/
val = initpc;
for(r = firstr; r != R; r = r1) {
r->pc = val;
p = r->prog;
p1 = P;
r1 = r->link;
if(r1 != R)
p1 = r1->prog;
for(; p != p1; p = p->link) {
switch(p->as) {
default:
val++;
break;
case ANOP:
case ADATA:
case AGLOBL:
case ANAME:
case ASIGNAME:
case AFUNCDATA:
break;
}
}
}
pc = val;
/*
* fix up branches
*/
if(debug['R'])
if(bany(&addrs))
print("addrs: %B\n", addrs);
r1 = 0; /* set */
for(r = firstr; r != R; r = r->link) {
p = r->prog;
if(p->to.type == D_BRANCH) {
p->to.offset = r->s2->pc;
p->to.u.branch = r->s2->prog;
}
r1 = r;
}
/*
* last pass
* eliminate nops
* free aux structures
*/
for(p = firstr->prog; p != P; p = p->link){
while(p->link && p->link->as == ANOP)
p->link = p->link->link;
}
if(debug['R'] && debug['v']) {
print("after pass 8 (fixup pc)\n");
for(p1=firstr->prog; p1!=P; p1=p1->link)
print("%P\n", p1);
print("\n");
}
if(r1 != R) {
r1->link = freer;
freer = firstr;
}
}
/*
* add mov b,rn
* just after r
*/
void
addmove(Reg *r, int bn, int rn, int f)
{
Prog *p, *p1;
Addr *a;
Var *v;
p1 = alloc(sizeof(*p1));
*p1 = zprog;
p = r->prog;
p1->link = p->link;
p->link = p1;
p1->lineno = p->lineno;
v = var + bn;
a = &p1->to;
a->sym = v->sym;
a->offset = v->offset;
a->etype = v->etype;
a->type = v->name;
p1->as = AMOVL;
if(v->etype == TCHAR || v->etype == TUCHAR)
p1->as = AMOVB;
if(v->etype == TSHORT || v->etype == TUSHORT)
p1->as = AMOVW;
p1->from.type = rn;
if(!f) {
p1->from = *a;
*a = zprog.from;
a->type = rn;
if(v->etype == TUCHAR)
p1->as = AMOVB;
if(v->etype == TUSHORT)
p1->as = AMOVW;
}
if(debug['R'])
print("%P\t.a%P\n", p, p1);
}
uint32
doregbits(int r)
{
uint32 b;
b = 0;
if(r >= D_INDIR)
r -= D_INDIR;
if(r >= D_AX && r <= D_DI)
b |= RtoB(r);
else
if(r >= D_AL && r <= D_BL)
b |= RtoB(r-D_AL+D_AX);
else
if(r >= D_AH && r <= D_BH)
b |= RtoB(r-D_AH+D_AX);
return b;
}
Bits
mkvar(Reg *r, Addr *a)
{
Var *v;
int i, t, n, et, z;
int32 o;
Bits bit;
LSym *s;
/*
* mark registers used
*/
t = a->type;
r->regu |= doregbits(t);
r->regu |= doregbits(a->index);
switch(t) {
default:
goto none;
case D_ADDR:
a->type = a->index;
bit = mkvar(r, a);
for(z=0; z<BITS; z++)
addrs.b[z] |= bit.b[z];
a->type = t;
goto none;
case D_EXTERN:
case D_STATIC:
case D_PARAM:
case D_AUTO:
n = t;
break;
}
s = a->sym;
if(s == nil)
goto none;
if(s->name[0] == '.')
goto none;
et = a->etype;
o = a->offset;
v = var;
for(i=0; i<nvar; i++) {
if(s == v->sym)
if(n == v->name)
if(o == v->offset)
goto out;
v++;
}
if(nvar >= NVAR) {
if(debug['w'] > 1 && s)
warn(Z, "variable not optimized: %s", s->name);
goto none;
}
i = nvar;
nvar++;
v = &var[i];
v->sym = s;
v->offset = o;
v->name = n;
v->etype = et;
if(debug['R'])
print("bit=%2d et=%2d %D\n", i, et, a);
out:
bit = blsh(i);
if(n == D_EXTERN || n == D_STATIC)
for(z=0; z<BITS; z++)
externs.b[z] |= bit.b[z];
if(n == D_PARAM)
for(z=0; z<BITS; z++)
params.b[z] |= bit.b[z];
if(v->etype != et || !typechlpfd[et]) /* funny punning */
for(z=0; z<BITS; z++)
addrs.b[z] |= bit.b[z];
return bit;
none:
return zbits;
}
void
prop(Reg *r, Bits ref, Bits cal)
{
Reg *r1, *r2;
int z;
for(r1 = r; r1 != R; r1 = r1->p1) {
for(z=0; z<BITS; z++) {
ref.b[z] |= r1->refahead.b[z];
if(ref.b[z] != r1->refahead.b[z]) {
r1->refahead.b[z] = ref.b[z];
change++;
}
cal.b[z] |= r1->calahead.b[z];
if(cal.b[z] != r1->calahead.b[z]) {
r1->calahead.b[z] = cal.b[z];
change++;
}
}
switch(r1->prog->as) {
case ACALL:
for(z=0; z<BITS; z++) {
cal.b[z] |= ref.b[z] | externs.b[z];
ref.b[z] = 0;
}
break;
case ATEXT:
for(z=0; z<BITS; z++) {
cal.b[z] = 0;
ref.b[z] = 0;
}
break;
case ARET:
for(z=0; z<BITS; z++) {
cal.b[z] = externs.b[z];
ref.b[z] = 0;
}
}
for(z=0; z<BITS; z++) {
ref.b[z] = (ref.b[z] & ~r1->set.b[z]) |
r1->use1.b[z] | r1->use2.b[z];
cal.b[z] &= ~(r1->set.b[z] | r1->use1.b[z] | r1->use2.b[z]);
r1->refbehind.b[z] = ref.b[z];
r1->calbehind.b[z] = cal.b[z];
}
if(r1->active)
break;
r1->active = 1;
}
for(; r != r1; r = r->p1)
for(r2 = r->p2; r2 != R; r2 = r2->p2link)
prop(r2, r->refbehind, r->calbehind);
}
/*
* find looping structure
*
* 1) find reverse postordering
* 2) find approximate dominators,
* the actual dominators if the flow graph is reducible
* otherwise, dominators plus some other non-dominators.
* See Matthew S. Hecht and Jeffrey D. Ullman,
* "Analysis of a Simple Algorithm for Global Data Flow Problems",
* Conf. Record of ACM Symp. on Principles of Prog. Langs, Boston, Massachusetts,
* Oct. 1-3, 1973, pp. 207-217.
* 3) find all nodes with a predecessor dominated by the current node.
* such a node is a loop head.
* recursively, all preds with a greater rpo number are in the loop
*/
int32
postorder(Reg *r, Reg **rpo2r, int32 n)
{
Reg *r1;
r->rpo = 1;
r1 = r->s1;
if(r1 && !r1->rpo)
n = postorder(r1, rpo2r, n);
r1 = r->s2;
if(r1 && !r1->rpo)
n = postorder(r1, rpo2r, n);
rpo2r[n] = r;
n++;
return n;
}
int32
rpolca(int32 *idom, int32 rpo1, int32 rpo2)
{
int32 t;
if(rpo1 == -1)
return rpo2;
while(rpo1 != rpo2){
if(rpo1 > rpo2){
t = rpo2;
rpo2 = rpo1;
rpo1 = t;
}
while(rpo1 < rpo2){
t = idom[rpo2];
if(t >= rpo2)
fatal(Z, "bad idom");
rpo2 = t;
}
}
return rpo1;
}
int
doms(int32 *idom, int32 r, int32 s)
{
while(s > r)
s = idom[s];
return s == r;
}
int
loophead(int32 *idom, Reg *r)
{
int32 src;
src = r->rpo;
if(r->p1 != R && doms(idom, src, r->p1->rpo))
return 1;
for(r = r->p2; r != R; r = r->p2link)
if(doms(idom, src, r->rpo))
return 1;
return 0;
}
void
loopmark(Reg **rpo2r, int32 head, Reg *r)
{
if(r->rpo < head || r->active == head)
return;
r->active = head;
r->loop += LOOP;
if(r->p1 != R)
loopmark(rpo2r, head, r->p1);
for(r = r->p2; r != R; r = r->p2link)
loopmark(rpo2r, head, r);
}
void
loopit(Reg *r, int32 nr)
{
Reg *r1;
int32 i, d, me;
if(nr > maxnr) {
rpo2r = alloc(nr * sizeof(Reg*));
idom = alloc(nr * sizeof(int32));
maxnr = nr;
}
d = postorder(r, rpo2r, 0);
if(d > nr)
fatal(Z, "too many reg nodes");
nr = d;
for(i = 0; i < nr / 2; i++){
r1 = rpo2r[i];
rpo2r[i] = rpo2r[nr - 1 - i];
rpo2r[nr - 1 - i] = r1;
}
for(i = 0; i < nr; i++)
rpo2r[i]->rpo = i;
idom[0] = 0;
for(i = 0; i < nr; i++){
r1 = rpo2r[i];
me = r1->rpo;
d = -1;
if(r1->p1 != R && r1->p1->rpo < me)
d = r1->p1->rpo;
for(r1 = r1->p2; r1 != nil; r1 = r1->p2link)
if(r1->rpo < me)
d = rpolca(idom, d, r1->rpo);
idom[i] = d;
}
for(i = 0; i < nr; i++){
r1 = rpo2r[i];
r1->loop++;
if(r1->p2 != R && loophead(idom, r1))
loopmark(rpo2r, i, r1);
}
}
void
synch(Reg *r, Bits dif)
{
Reg *r1;
int z;
for(r1 = r; r1 != R; r1 = r1->s1) {
for(z=0; z<BITS; z++) {
dif.b[z] = (dif.b[z] &
~(~r1->refbehind.b[z] & r1->refahead.b[z])) |
r1->set.b[z] | r1->regdiff.b[z];
if(dif.b[z] != r1->regdiff.b[z]) {
r1->regdiff.b[z] = dif.b[z];
change++;
}
}
if(r1->active)
break;
r1->active = 1;
for(z=0; z<BITS; z++)
dif.b[z] &= ~(~r1->calbehind.b[z] & r1->calahead.b[z]);
if(r1->s2 != R)
synch(r1->s2, dif);
}
}
uint32
allreg(uint32 b, Rgn *r)
{
Var *v;
int i;
v = var + r->varno;
r->regno = 0;
switch(v->etype) {
default:
diag(Z, "unknown etype %d/%d", bitno(b), v->etype);
break;
case TCHAR:
case TUCHAR:
case TSHORT:
case TUSHORT:
case TINT:
case TUINT:
case TLONG:
case TULONG:
case TIND:
case TARRAY:
i = BtoR(~b);
if(i && r->cost > 0) {
r->regno = i;
return RtoB(i);
}
break;
case TDOUBLE:
case TFLOAT:
break;
}
return 0;
}
void
paint1(Reg *r, int bn)
{
Reg *r1;
Prog *p;
int z;
uint32 bb;
z = bn/32;
bb = 1L<<(bn%32);
if(r->act.b[z] & bb)
return;
for(;;) {
if(!(r->refbehind.b[z] & bb))
break;
r1 = r->p1;
if(r1 == R)
break;
if(!(r1->refahead.b[z] & bb))
break;
if(r1->act.b[z] & bb)
break;
r = r1;
}
if(LOAD(r) & ~(r->set.b[z]&~(r->use1.b[z]|r->use2.b[z])) & bb) {
change -= CLOAD * r->loop;
if(debug['R'] && debug['v'])
print("%d%P\td %B $%d\n", r->loop,
r->prog, blsh(bn), change);
}
for(;;) {
r->act.b[z] |= bb;
p = r->prog;
if(r->use1.b[z] & bb) {
change += CREF * r->loop;
if(p->as == AFMOVL)
if(BtoR(bb) != D_F0)
change = -CINF;
if(debug['R'] && debug['v'])
print("%d%P\tu1 %B $%d\n", r->loop,
p, blsh(bn), change);
}
if((r->use2.b[z]|r->set.b[z]) & bb) {
change += CREF * r->loop;
if(p->as == AFMOVL)
if(BtoR(bb) != D_F0)
change = -CINF;
if(debug['R'] && debug['v'])
print("%d%P\tu2 %B $%d\n", r->loop,
p, blsh(bn), change);
}
if(STORE(r) & r->regdiff.b[z] & bb) {
change -= CLOAD * r->loop;
if(p->as == AFMOVL)
if(BtoR(bb) != D_F0)
change = -CINF;
if(debug['R'] && debug['v'])
print("%d%P\tst %B $%d\n", r->loop,
p, blsh(bn), change);
}
if(r->refbehind.b[z] & bb)
for(r1 = r->p2; r1 != R; r1 = r1->p2link)
if(r1->refahead.b[z] & bb)
paint1(r1, bn);
if(!(r->refahead.b[z] & bb))
break;
r1 = r->s2;
if(r1 != R)
if(r1->refbehind.b[z] & bb)
paint1(r1, bn);
r = r->s1;
if(r == R)
break;
if(r->act.b[z] & bb)
break;
if(!(r->refbehind.b[z] & bb))
break;
}
}
uint32
regset(Reg *r, uint32 bb)
{
uint32 b, set;
Addr v;
int c;
set = 0;
v = zprog.from;
while(b = bb & ~(bb-1)) {
v.type = BtoR(b);
c = copyu(r->prog, &v, A);
if(c == 3)
set |= b;
bb &= ~b;
}
return set;
}
uint32
reguse(Reg *r, uint32 bb)
{
uint32 b, set;
Addr v;
int c;
set = 0;
v = zprog.from;
while(b = bb & ~(bb-1)) {
v.type = BtoR(b);
c = copyu(r->prog, &v, A);
if(c == 1 || c == 2 || c == 4)
set |= b;
bb &= ~b;
}
return set;
}
uint32
paint2(Reg *r, int bn)
{
Reg *r1;
int z;
uint32 bb, vreg, x;
z = bn/32;
bb = 1L << (bn%32);
vreg = regbits;
if(!(r->act.b[z] & bb))
return vreg;
for(;;) {
if(!(r->refbehind.b[z] & bb))
break;
r1 = r->p1;
if(r1 == R)
break;
if(!(r1->refahead.b[z] & bb))
break;
if(!(r1->act.b[z] & bb))
break;
r = r1;
}
for(;;) {
r->act.b[z] &= ~bb;
vreg |= r->regu;
if(r->refbehind.b[z] & bb)
for(r1 = r->p2; r1 != R; r1 = r1->p2link)
if(r1->refahead.b[z] & bb)
vreg |= paint2(r1, bn);
if(!(r->refahead.b[z] & bb))
break;
r1 = r->s2;
if(r1 != R)
if(r1->refbehind.b[z] & bb)
vreg |= paint2(r1, bn);
r = r->s1;
if(r == R)
break;
if(!(r->act.b[z] & bb))
break;
if(!(r->refbehind.b[z] & bb))
break;
}
bb = vreg;
for(; r; r=r->s1) {
x = r->regu & ~bb;
if(x) {
vreg |= reguse(r, x);
bb |= regset(r, x);
}
}
return vreg;
}
void
paint3(Reg *r, int bn, int32 rb, int rn)
{
Reg *r1;
Prog *p;
int z;
uint32 bb;
z = bn/32;
bb = 1L << (bn%32);
if(r->act.b[z] & bb)
return;
for(;;) {
if(!(r->refbehind.b[z] & bb))
break;
r1 = r->p1;
if(r1 == R)
break;
if(!(r1->refahead.b[z] & bb))
break;
if(r1->act.b[z] & bb)
break;
r = r1;
}
if(LOAD(r) & ~(r->set.b[z] & ~(r->use1.b[z]|r->use2.b[z])) & bb)
addmove(r, bn, rn, 0);
for(;;) {
r->act.b[z] |= bb;
p = r->prog;
if(r->use1.b[z] & bb) {
if(debug['R'])
print("%P", p);
addreg(&p->from, rn);
if(debug['R'])
print("\t.c%P\n", p);
}
if((r->use2.b[z]|r->set.b[z]) & bb) {
if(debug['R'])
print("%P", p);
addreg(&p->to, rn);
if(debug['R'])
print("\t.c%P\n", p);
}
if(STORE(r) & r->regdiff.b[z] & bb)
addmove(r, bn, rn, 1);
r->regu |= rb;
if(r->refbehind.b[z] & bb)
for(r1 = r->p2; r1 != R; r1 = r1->p2link)
if(r1->refahead.b[z] & bb)
paint3(r1, bn, rb, rn);
if(!(r->refahead.b[z] & bb))
break;
r1 = r->s2;
if(r1 != R)
if(r1->refbehind.b[z] & bb)
paint3(r1, bn, rb, rn);
r = r->s1;
if(r == R)
break;
if(r->act.b[z] & bb)
break;
if(!(r->refbehind.b[z] & bb))
break;
}
}
void
addreg(Addr *a, int rn)
{
a->sym = 0;
a->offset = 0;
a->type = rn;
}
int32
RtoB(int r)
{
if(r < D_AX || r > D_DI)
return 0;
return 1L << (r-D_AX);
}
int
BtoR(int32 b)
{
b &= 0xffL;
if(b == 0)
return 0;
return bitno(b) + D_AX;
}
/* what instruction does a JMP to p eventually land on? */
static Reg*
chasejmp(Reg *r, int *jmploop)
{
int n;
n = 0;
for(; r; r=r->s2) {
if(r->prog->as != AJMP || r->prog->to.type != D_BRANCH)
break;
if(++n > 10) {
*jmploop = 1;
break;
}
}
return r;
}
/* mark all code reachable from firstp as alive */
static void
mark(Reg *firstr)
{
Reg *r;
Prog *p;
for(r=firstr; r; r=r->link) {
if(r->active)
break;
r->active = 1;
p = r->prog;
if(p->as != ACALL && p->to.type == D_BRANCH)
mark(r->s2);
if(p->as == AJMP || p->as == ARET || p->as == AUNDEF)
break;
}
}
/*
* the code generator depends on being able to write out JMP
* instructions that it can jump to now but fill in later.
* the linker will resolve them nicely, but they make the code
* longer and more difficult to follow during debugging.
* remove them.
*/
static void
fixjmp(Reg *firstr)
{
int jmploop;
Reg *r;
Prog *p;
if(debug['R'] && debug['v'])
print("\nfixjmp\n");
// pass 1: resolve jump to AJMP, mark all code as dead.
jmploop = 0;
for(r=firstr; r; r=r->link) {
p = r->prog;
if(debug['R'] && debug['v'])
print("%04d %P\n", (int)r->pc, p);
if(p->as != ACALL && p->to.type == D_BRANCH && r->s2 && r->s2->prog->as == AJMP) {
r->s2 = chasejmp(r->s2, &jmploop);
p->to.offset = r->s2->pc;
p->to.u.branch = r->s2->prog;
if(debug['R'] && debug['v'])
print("->%P\n", p);
}
r->active = 0;
}
if(debug['R'] && debug['v'])
print("\n");
// pass 2: mark all reachable code alive
mark(firstr);
// pass 3: delete dead code (mostly JMPs).
for(r=firstr; r; r=r->link) {
if(!r->active) {
p = r->prog;
if(p->link == P && p->as == ARET && r->p1 && r->p1->prog->as != ARET) {
// This is the final ARET, and the code so far doesn't have one.
// Let it stay.
} else {
if(debug['R'] && debug['v'])
print("del %04d %P\n", (int)r->pc, p);
p->as = ANOP;
}
}
}
// pass 4: elide JMP to next instruction.
// only safe if there are no jumps to JMPs anymore.
if(!jmploop) {
for(r=firstr; r; r=r->link) {
p = r->prog;
if(p->as == AJMP && p->to.type == D_BRANCH && r->s2 == r->link) {
if(debug['R'] && debug['v'])
print("del %04d %P\n", (int)r->pc, p);
p->as = ANOP;
}
}
}
// fix back pointers.
for(r=firstr; r; r=r->link) {
r->p2 = R;
r->p2link = R;
}
for(r=firstr; r; r=r->link) {
if(r->s2) {
r->p2link = r->s2->p2;
r->s2->p2 = r;
}
}
if(debug['R'] && debug['v']) {
print("\n");
for(r=firstr; r; r=r->link)
print("%04d %P\n", (int)r->pc, r->prog);
print("\n");
}
}