ref: 2459e34d77e2e21ef829c0dfaafd99433899494f
dir: /limbo/optim.c/
#include "limbo.h"
#define bzero bbzero /* bsd name space pollution */
/*
(r, s) := f(); => r, s have def on same pc
s = g(); => this def kills previous r def (and s def)
solution: r has def pc, s has def pc+1 and next instruction has pc pc+2
*/
#define BLEN (8*sizeof(ulong))
#define BSHIFT 5 /* assumes ulong 4 */
#define BMASK (BLEN-1)
#define SIGN(n) (1<<(n-1))
#define MSK(n) (SIGN(n)|(SIGN(n)-1))
#define MASK(a, b) (MSK((b)-(a)+1)<<(a))
#define isnilsrc(s) ((s)->start.line == 0 && (s)->stop.line == 0 && (s)->start.pos == 0 && (s)->stop.pos == 0)
#define limbovar(d) ((d)->sym->name[0] != '.')
#define structure(t) ((t)->kind == Tadt || (t)->kind == Ttuple)
enum
{
Bclr,
Band,
Bandinv,
Bstore,
Bandrev,
Bnoop,
Bxor,
Bor,
Bnor,
Bequiv,
Binv,
Bimpby,
Brev,
Bimp,
Bnand,
Bset,
};
enum
{
Suse = 1,
Muse = 2,
Duse = 4,
Sdef = 8,
Mdef = 16,
Ddef = 32,
Tuse1 = 64, /* fixed point temporary */
Tuse2 = 128, /* fixed point temporary */
Mduse = 256, /* D used if M nil */
None = 0,
Unop = Suse|Ddef,
Cunop = Muse|Ddef,
Threop = Suse|Muse|Ddef,
Binop = Suse|Muse|Ddef|Mduse,
Mbinop = Suse|Mdef|Duse, /* strange */
Abinop=Suse|Duse|Ddef,
Mabinop = Suse|Muse|Duse|Ddef,
Use1 = Suse,
Use2 = Suse|Duse,
Use3 = Suse|Muse|Duse,
};
enum
{
Sshift = 10,
Mshift = 5,
Dshift = 0,
};
#define S(x) ((x)<<Sshift)
#define M(x) ((x)<<Mshift)
#define D(x) ((x)<<Dshift)
#define SS(x) (((x)>>Sshift)&0x1f)
#define SM(x) (((x)>>Mshift)&0x1f)
#define SD(x) (((x)>>Dshift)&0x1f)
enum
{
I = 0, /* ignore */
B = 1, /* byte */
W = 4, /* int */
P = 4, /* pointer */
A = 4, /* array */
C = 4, /* string */
X = 4, /* fixed */
R = 4, /* float */
L = 8, /* big */
F = 8, /* real */
Sh = 2, /* short */
Pc = 4, /* pc */
Mp = 16, /* memory */
Bop2 = S(B)|D(B),
Bop = S(B)|M(B)|D(B),
Bopb = S(B)|M(B)|D(Pc),
Wop2 = S(W)|D(W),
Wop = S(W)|M(W)|D(W),
Wopb = S(W)|M(W)|D(Pc),
Lop2 = S(L)|D(L),
Lop = S(L)|M(L)|D(L),
Lopb = S(L)|M(L)|D(Pc),
Cop2 = Wop2,
Cop = Wop,
Copb = Wopb,
Fop2 = Lop2,
Fop = Lop,
Fopb = Lopb,
Xop = Wop,
};
typedef struct Array Array;
typedef struct Bits Bits;
typedef struct Blist Blist;
typedef struct Block Block;
typedef struct Idlist Idlist;
typedef struct Optab Optab;
struct Array
{
int n;
int m;
Block **a;
};
struct Bits
{
int n;
ulong *b;
};
struct Blist
{
Block *block;
Blist *next;
};
struct Block
{
int dfn;
int flags;
Inst *first;
Inst *last;
Block *prev;
Block *next;
Blist *pred;
Blist *succ;
Bits kill;
Bits gen;
Bits in;
Bits out;
};
struct Idlist
{
int id;
Idlist *next;
};
struct Optab
{
short flags;
short size;
};
Block zblock;
Decl *regdecls;
Idlist *frelist;
Idlist *deflist;
Idlist *uselist;
static void
addlist(Idlist **hd, int id)
{
Idlist *il;
if(frelist == nil)
il = (Idlist*)malloc(sizeof(Idlist));
else{
il = frelist;
frelist = frelist->next;
}
il->id = id;
il->next = *hd;
*hd = il;
}
static void
freelist(Idlist **hd)
{
Idlist *il;
for(il = *hd; il != nil && il->next != nil; il = il->next)
;
if(il != nil){
il->next = frelist;
frelist = *hd;
*hd = nil;
}
}
Optab opflags[] = {
/* INOP */ None, 0,
/* IALT */ Unop, S(Mp)|D(W),
/* INBALT */ Unop, S(Mp)|D(W),
/* IGOTO */ Use2, S(W)|D(I),
/* ICALL */ Use2, S(P)|D(Pc),
/* IFRAME */ Unop, S(W)|D(P),
/* ISPAWN */ Use2, S(P)|D(Pc),
/* IRUNT */ None, 0,
/* ILOAD */ Threop, S(C)|M(P)|D(P),
/* IMCALL */ Use3, S(P)|M(W)|D(P),
/* IMSPAWN */ Use3, S(P)|M(W)|D(P),
/* IMFRAME */ Threop, S(P)|M(W)|D(P),
/* IRET */ None, 0,
/* IJMP */ Duse, D(Pc),
/* ICASE */ Use2, S(W)|D(I),
/* IEXIT */ None, 0,
/* INEW */ Unop, S(W)|D(P),
/* INEWA */ Threop, S(W)|M(W)|D(P),
/* INEWCB */ Cunop, M(W)|D(P),
/* INEWCW */ Cunop, M(W)|D(P),
/* INEWCF */ Cunop, M(W)|D(P),
/* INEWCP */ Cunop, M(W)|D(P),
/* INEWCM */ Threop, S(W)|M(W)|D(P),
/* INEWCMP */ Threop, S(W)|M(W)|D(P),
/* ISEND */ Use2, S(Mp)|D(P),
/* IRECV */ Unop, S(P)|D(Mp),
/* ICONSB */ Abinop, S(B)|D(P),
/* ICONSW */ Abinop, S(W)|D(P),
/* ICONSP */ Abinop, S(P)|D(P),
/* ICONSF */ Abinop, S(F)|D(P),
/* ICONSM */ Mabinop, S(Mp)|M(W)|D(P),
/* ICONSMP */ Mabinop, S(Mp)|M(W)|D(P),
/* IHEADB */ Unop, S(P)|D(B),
/* IHEADW */ Unop, S(P)|D(W),
/* IHEADP */ Unop, S(P)|D(P),
/* IHEADF */ Unop, S(P)|D(F),
/* IHEADM */ Threop, S(P)|M(W)|D(Mp),
/* IHEADMP */ Threop, S(P)|M(W)|D(Mp),
/* ITAIL */ Unop, S(P)|D(P),
/* ILEA */ Ddef, S(Mp)|D(P), /* S done specially cos of ALT */
/* IINDX */ Mbinop, S(P)|M(P)|D(W),
/* IMOVP */ Unop, S(P)|D(P),
/* IMOVM */ Threop, S(Mp)|M(W)|D(Mp),
/* IMOVMP */ Threop, S(Mp)|M(W)|D(Mp),
/* IMOVB */ Unop, Bop2,
/* IMOVW */ Unop, Wop2,
/* IMOVF */ Unop, Fop2,
/* ICVTBW */ Unop, S(B)|D(W),
/* ICVTWB */ Unop, S(W)|D(B),
/* ICVTFW */ Unop, S(F)|D(W),
/* ICVTWF */ Unop, S(W)|D(F),
/* ICVTCA */ Unop, S(C)|D(A),
/* ICVTAC */ Unop, S(A)|D(C),
/* ICVTWC */ Unop, S(W)|D(C),
/* ICVTCW */ Unop, S(C)|D(W),
/* ICVTFC */ Unop, S(F)|D(C),
/* ICVTCF */ Unop, S(C)|D(F),
/* IADDB */ Binop, Bop,
/* IADDW */ Binop, Wop,
/* IADDF */ Binop, Fop,
/* ISUBB */ Binop, Bop,
/* ISUBW */ Binop, Wop,
/* ISUBF */ Binop, Fop,
/* IMULB */ Binop, Bop,
/* IMULW */ Binop, Wop,
/* IMULF */ Binop, Fop,
/* IDIVB */ Binop, Bop,
/* IDIVW */ Binop, Wop,
/* IDIVF */ Binop, Fop,
/* IMODW */ Binop, Wop,
/* IMODB */ Binop, Bop,
/* IANDB */ Binop, Bop,
/* IANDW */ Binop, Wop,
/* IORB */ Binop, Bop,
/* IORW */ Binop, Wop,
/* IXORB */ Binop, Bop,
/* IXORW */ Binop, Wop,
/* ISHLB */ Binop, S(W)|M(B)|D(B),
/* ISHLW */ Binop, Wop,
/* ISHRB */ Binop, S(W)|M(B)|D(B),
/* ISHRW */ Binop, Wop,
/* IINSC */ Mabinop, S(W)|M(W)|D(C),
/* IINDC */ Threop, S(C)|M(W)|D(W),
/* IADDC */ Binop, Cop,
/* ILENC */ Unop, S(C)|D(W),
/* ILENA */ Unop, S(A)|D(W),
/* ILENL */ Unop, S(P)|D(W),
/* IBEQB */ Use3, Bopb,
/* IBNEB */ Use3, Bopb,
/* IBLTB */ Use3, Bopb,
/* IBLEB */ Use3, Bopb,
/* IBGTB */ Use3, Bopb,
/* IBGEB */ Use3, Bopb,
/* IBEQW */ Use3, Wopb,
/* IBNEW */ Use3, Wopb,
/* IBLTW */ Use3, Wopb,
/* IBLEW */ Use3, Wopb,
/* IBGTW */ Use3, Wopb,
/* IBGEW */ Use3, Wopb,
/* IBEQF */ Use3, Fopb,
/* IBNEF */ Use3, Fopb,
/* IBLTF */ Use3, Fopb,
/* IBLEF */ Use3, Fopb,
/* IBGTF */ Use3, Fopb,
/* IBGEF */ Use3, Fopb,
/* IBEQC */ Use3, Copb,
/* IBNEC */ Use3, Copb,
/* IBLTC */ Use3, Copb,
/* IBLEC */ Use3, Copb,
/* IBGTC */ Use3, Copb,
/* IBGEC */ Use3, Copb,
/* ISLICEA */ Mabinop, S(W)|M(W)|D(P),
/* ISLICELA */ Use3, S(P)|M(W)|D(P),
/* ISLICEC */ Mabinop, S(W)|M(W)|D(C),
/* IINDW */ Mbinop, S(P)|M(P)|D(W),
/* IINDF */ Mbinop, S(P)|M(P)|D(W),
/* IINDB */ Mbinop, S(P)|M(P)|D(W),
/* INEGF */ Unop, Fop2,
/* IMOVL */ Unop, Lop2,
/* IADDL */ Binop, Lop,
/* ISUBL */ Binop, Lop,
/* IDIVL */ Binop, Lop,
/* IMODL */ Binop, Lop,
/* IMULL */ Binop, Lop,
/* IANDL */ Binop, Lop,
/* IORL */ Binop, Lop,
/* IXORL */ Binop, Lop,
/* ISHLL */ Binop, S(W)|M(L)|D(L),
/* ISHRL */ Binop, S(W)|M(L)|D(L),
/* IBNEL */ Use3, Lopb,
/* IBLTL */ Use3, Lopb,
/* IBLEL */ Use3, Lopb,
/* IBGTL */ Use3, Lopb,
/* IBGEL */ Use3, Lopb,
/* IBEQL */ Use3, Lopb,
/* ICVTLF */ Unop, S(L)|D(F),
/* ICVTFL */ Unop, S(F)|D(L),
/* ICVTLW */ Unop, S(L)|D(W),
/* ICVTWL */ Unop, S(W)|D(L),
/* ICVTLC */ Unop, S(L)|D(C),
/* ICVTCL */ Unop, S(C)|D(L),
/* IHEADL */ Unop, S(P)|D(L),
/* ICONSL */ Abinop, S(L)|D(P),
/* INEWCL */ Cunop, M(W)|D(P),
/* ICASEC */ Use2, S(C)|D(I),
/* IINDL */ Mbinop, S(P)|M(P)|D(W),
/* IMOVPC */ Unop, S(W)|D(P),
/* ITCMP */ Use2, S(P)|D(P),
/* IMNEWZ */ Threop, S(P)|M(W)|D(P),
/* ICVTRF */ Unop, S(R)|D(F),
/* ICVTFR */ Unop, S(F)|D(R),
/* ICVTWS */ Unop, S(W)|D(Sh),
/* ICVTSW */ Unop, S(Sh)|D(W),
/* ILSRW */ Binop, Wop,
/* ILSRL */ Binop, S(W)|M(L)|D(L),
/* IECLR */ None, 0,
/* INEWZ */ Unop, S(W)|D(P),
/* INEWAZ */ Threop, S(W)|M(W)|D(P),
/* IRAISE */ Use1, S(P),
/* ICASEL */ Use2, S(L)|D(I),
/* IMULX */ Binop|Tuse2, Xop,
/* IDIVX */ Binop|Tuse2, Xop,
/* ICVTXX */ Threop, Xop,
/* IMULX0 */ Binop|Tuse1|Tuse2, Xop,
/* IDIVX0 */ Binop|Tuse1|Tuse2, Xop,
/* ICVTXX0 */ Threop|Tuse1, Xop,
/* IMULX1 */ Binop|Tuse1|Tuse2, Xop,
/* IDIVX1 */ Binop|Tuse1|Tuse2, Xop,
/* ICVTXX1 */ Threop|Tuse1, Xop,
/* ICVTFX */ Threop, S(F)|M(F)|D(X),
/* ICVTXF */ Threop, S(X)|M(F)|D(F),
/* IEXPW */ Binop, S(W)|M(W)|D(W),
/* IEXPL */ Binop, S(W)|M(L)|D(L),
/* IEXPF */ Binop, S(W)|M(F)|D(F),
/* ISELF */ Ddef, D(P),
/* IEXC */ None, 0,
/* IEXC0 */ None, 0,
/* INOOP */ None, 0,
};
/*
static int
pop(int i)
{
i = (i & 0x55555555) + ((i>>1) & 0x55555555);
i = (i & 0x33333333) + ((i>>2) & 0x33333333);
i = (i & 0x0F0F0F0F) + ((i>>4) & 0x0F0F0F0F);
i = (i & 0x00FF00FF) + ((i>>8) & 0x00FF00FF);
i = (i & 0x0000FFFF) + ((i>>16) & 0x0000FFFF);
return i;
}
*/
static int
bitc(uint x)
{
uint n;
n = (x>>1)&0x77777777;
x -= n;
n = (n>>1)&0x77777777;
x -= n;
n = (n>>1)&0x77777777;
x -= n;
x = (x+(x>>4))&0x0f0f0f0f;
x *= 0x01010101;
return x>>24;
}
/*
static int
top(uint x)
{
int i;
for(i = -1; x; i++)
x >>= 1;
return i;
}
*/
static int
topb(uint x)
{
int i;
if(x == 0)
return -1;
i = 0;
if(x&0xffff0000){
i |= 16;
x >>= 16;
}
if(x&0xff00){
i |= 8;
x >>= 8;
}
if(x&0xf0){
i |= 4;
x >>= 4;
}
if(x&0xc){
i |= 2;
x >>= 2;
}
if(x&0x2)
i |= 1;
return i;
}
/*
static int
lowb(uint x)
{
int i;
if(x == 0)
return -1;
for(i = BLEN; x; i--)
x <<= 1;
return i;
}
*/
static int
lowb(uint x)
{
int i;
if(x == 0)
return -1;
i = 0;
if((x&0xffff) == 0){
i |= 16;
x >>= 16;
}
if((x&0xff) == 0){
i |= 8;
x >>= 8;
}
if((x&0xf) == 0){
i |= 4;
x >>= 4;
}
if((x&0x3) == 0){
i |= 2;
x >>= 2;
}
return i+1-(x&1);
}
static void
pbit(int x, int n)
{
int i, m;
m = 1;
for(i = 0; i < BLEN; i++){
if(x&m)
print("%d ", i+n);
m <<= 1;
}
}
static ulong
bop(int o, ulong s, ulong d)
{
switch(o){
case Bclr: return 0;
case Band: return s & d;
case Bandinv: return s & ~d;
case Bstore: return s;
case Bandrev: return ~s & d;
case Bnoop: return d;
case Bxor: return s ^ d;
case Bor: return s | d;
case Bnor: return ~(s | d);
case Bequiv: return ~(s ^ d);
case Binv: return ~d;
case Bimpby: return s | ~d;
case Brev: return ~s;
case Bimp: return ~s | d;
case Bnand: return ~(s & d);
case Bset: return 0xffffffff;
}
return 0;
}
static Bits
bnew(int n, int bits)
{
Bits b;
if(bits)
b.n = (n+BLEN-1)>>BSHIFT;
else
b.n = n;
b.b = allocmem(b.n*sizeof(ulong));
memset(b.b, 0, b.n*sizeof(ulong));
return b;
}
static void
bfree(Bits b)
{
free(b.b);
}
static void
bset(Bits b, int n)
{
b.b[n>>BSHIFT] |= 1<<(n&BMASK);
}
static void
bclr(Bits b, int n)
{
b.b[n>>BSHIFT] &= ~(1<<(n&BMASK));
}
static int
bmem(Bits b, int n)
{
return b.b[n>>BSHIFT] & (1<<(n&BMASK));
}
static void
bsets(Bits b, int m, int n)
{
int i, c1, c2;
c1 = m>>BSHIFT;
c2 = n>>BSHIFT;
m &= BMASK;
n &= BMASK;
if(c1 == c2){
b.b[c1] |= MASK(m, n);
return;
}
for(i = c1+1; i < c2; i++)
b.b[i] = 0xffffffff;
b.b[c1] |= MASK(m, BLEN-1);
b.b[c2] |= MASK(0, n);
}
static void
bclrs(Bits b, int m, int n)
{
int i, c1, c2;
if(n < 0)
n = (b.n<<BSHIFT)-1;
c1 = m>>BSHIFT;
c2 = n>>BSHIFT;
m &= BMASK;
n &= BMASK;
if(c1 == c2){
b.b[c1] &= ~MASK(m, n);
return;
}
for(i = c1+1; i < c2; i++)
b.b[i] = 0;
b.b[c1] &= ~MASK(m, BLEN-1);
b.b[c2] &= ~MASK(0, n);
}
/* b = a op b */
static Bits
boper(int o, Bits a, Bits b)
{
int i, n;
n = a.n;
if(b.n != n)
fatal("boper %d %d %d", o, a.n, b.n);
for(i = 0; i < n; i++)
b.b[i] = bop(o, a.b[i], b.b[i]);
return b;
}
static int
beq(Bits a, Bits b)
{
int i, n;
n = a.n;
for(i = 0; i < n; i++)
if(a.b[i] != b.b[i])
return 0;
return 1;
}
static int
bzero(Bits b)
{
int i, n;
n = b.n;
for(i = 0; i < n; i++)
if(b.b[i] != 0)
return 0;
return 1;
}
static int
bitcnt(Bits b)
{
int i, m, n;
m = b.n;
n = 0;
for(i = 0; i < m; i++)
n += bitc(b.b[i]);
return n;
}
static int
topbit(Bits b)
{
int i, n;
n = b.n;
for(i = n-1; i >= 0; i--)
if(b.b[i] != 0)
return (i<<BSHIFT)+topb(b.b[i]);
return -1;
}
static int
lowbit(Bits b)
{
int i, n;
n = b.n;
for(i = 0; i < n; i++)
if(b.b[i] != 0)
return (i<<BSHIFT)+lowb(b.b[i]);
return -1;
}
static void
pbits(Bits b)
{
int i, n;
n = b.n;
for(i = 0; i < n; i++)
pbit(b.b[i], i<<BSHIFT);
}
static char*
decname(Decl *d)
{
if(d->sym == nil)
return "<nil>";
return d->sym->name;
}
static void
warning(Inst *i, char *s, Decl *d, Decl *sd)
{
int n;
char *f;
Decl *ds;
n = 0;
for(ds = sd; ds != nil; ds = ds->next)
if(ds->link == d)
n += strlen(ds->sym->name)+1;
if(n == 0){
warn(i->src.start, "%s: %s", d->sym->name, s);
return;
}
n += strlen(d->sym->name);
f = malloc(n+1);
strcpy(f, d->sym->name);
for(ds = sd; ds != nil; ds = ds->next){
if(ds->link == d){
strcat(f, "/");
strcat(f, ds->sym->name);
}
}
warn(i->src.start, "%s: %s", f, s);
free(f);
}
static int
inspc(Inst *in)
{
int n;
Inst *i;
n = 0;
for(i = in; i != nil; i = i->next)
i->pc = n++;
return n;
}
static Inst*
pc2i(Block *b, int pc)
{
Inst *i;
for( ; b != nil; b = b->next){
if(pc > b->last->pc)
continue;
for(i = b->first; ; i = i->next){
if(i->pc == pc)
return i;
if(i == b->last)
fatal("pc2i a");
}
}
fatal("pc2i b");
return nil;
}
static void
padr(int am, Addr *a, Inst *br)
{
long reg;
if(br != nil){
print("$%ld", br->pc);
return;
}
reg = a->reg;
if(a->decl != nil && am != Adesc)
reg += a->decl->offset;
switch(am){
case Anone:
print("-");
break;
case Aimm:
case Apc:
case Adesc:
print("$%ld", a->offset);
break;
case Aoff:
print("$%ld", a->decl->iface->offset);
break;
case Anoff:
print("-$%ld", a->decl->iface->offset);
break;
case Afp:
print("%ld(fp)", reg);
break;
case Afpind:
print("%ld(%ld(fp))", a->offset, reg);
break;
case Amp:
print("%ld(mp)", reg);
break;
case Ampind:
print("%ld(%ld(mp))", a->offset, reg);
break;
case Aldt:
print("$%ld", reg);
break;
case Aerr:
default:
print("%ld(%ld(?%d?))", a->offset, reg, am);
break;
}
}
static void
pins(Inst *i)
{
/* print("%L %ld ", i->src.start, i->pc); */
print(" %ld ", i->pc);
if(i->op < MAXDIS)
print("%s", instname[i->op]);
else
print("noop");
print(" ");
padr(i->sm, &i->s, nil);
print(", ");
padr(i->mm, &i->m, nil);
print(", ");
padr(i->dm, &i->d, i->branch);
print("\n");
}
static void
blfree(Blist *bl)
{
Blist *nbl;
for( ; bl != nil; bl = nbl){
nbl = bl->next;
free(bl);
}
}
static void
freebits(Bits *bs, int nv)
{
int i;
for(i = 0; i < nv; i++)
bfree(bs[i]);
free(bs);
}
static void
freeblks(Block *b)
{
Block *nb;
for( ; b != nil; b = nb){
blfree(b->pred);
blfree(b->succ);
bfree(b->kill);
bfree(b->gen);
bfree(b->in);
bfree(b->out);
nb = b->next;
free(b);
}
}
static int
len(Decl *d)
{
int n;
n = 0;
for( ; d != nil; d = d->next)
n++;
return n;
}
static Bits*
allocbits(int nv, int npc)
{
int i;
Bits *defs;
defs = (Bits*)allocmem(nv*sizeof(Bits));
for(i = 0; i < nv; i++)
defs[i] = bnew(npc, 1);
return defs;
}
static int
bitcount(Bits *bs, int nv)
{
int i, n;
n = 0;
for(i = 0; i < nv; i++)
n += bitcnt(bs[i]);
return n;
}
static Block*
mkblock(Inst *i)
{
Block *b;
b = allocmem(sizeof(Block));
*b = zblock;
b->first = b->last = i;
return b;
}
static Blist*
mkblist(Block *b, Blist *nbl)
{
Blist *bl;
bl = allocmem(sizeof(Blist));
bl->block = b;
bl->next = nbl;
return bl;
}
static void
leader(Inst *i, Array *ab)
{
int m, n;
Block *b, **a;
if(i != nil && i->pc == 0){
if((n = ab->n) == (m = ab->m)){
a = ab->a;
ab->a = allocmem(2*m*sizeof(Block*));
memcpy(ab->a, a, m*sizeof(Block*));
ab->m = 2*m;
free(a);
}
b = mkblock(i);
b->dfn = n;
ab->a[n] = b;
i->pc = ab->n = n+1;
}
}
static Block*
findb(Inst *i, Array *ab)
{
if(i == nil)
return nil;
if(i->pc <= 0)
fatal("pc <= 0 in findb");
return ab->a[i->pc-1];
}
static int
memb(Block *b, Blist *bl)
{
for( ; bl != nil; bl = bl->next)
if(bl->block == b)
return 1;
return 0;
}
static int
canfallthrough(Inst *i)
{
if(i == nil)
return 0;
switch(i->op){
case IGOTO:
case ICASE:
case ICASEL:
case ICASEC:
case IRET:
case IEXIT:
case IRAISE:
case IJMP:
return 0;
case INOOP:
return i->branch != nil;
}
return 1;
}
static void
predsucc(Block *b1, Block *b2)
{
if(b1 == nil || b2 == nil)
return;
if(!memb(b1, b2->pred))
b2->pred = mkblist(b1, b2->pred);
if(!memb(b2, b1->succ))
b1->succ = mkblist(b2, b1->succ);
}
static Block*
mkblocks(Inst *in, int *nb)
{
Inst *i;
Block *b, *firstb, *lastb;
Label *lab;
Array *ab;
int j, n;
ab = allocmem(sizeof(Array));
ab->n = 0;
ab->m = 16;
ab->a = allocmem(ab->m*sizeof(Block*));
leader(in, ab);
for(i = in; i != nil; i = i->next){
switch(i->op){
case IGOTO:
case ICASE:
case ICASEL:
case ICASEC:
case INOOP:
if(i->op == INOOP && i->branch != nil){
leader(i->branch, ab);
leader(i->next, ab);
break;
}
leader(i->d.decl->ty->cse->iwild, ab);
lab = i->d.decl->ty->cse->labs;
n = i->d.decl->ty->cse->nlab;
for(j = 0; j < n; j++)
leader(lab[j].inst, ab);
leader(i->next, ab);
break;
case IRET:
case IEXIT:
case IRAISE:
leader(i->next, ab);
break;
case IJMP:
leader(i->branch, ab);
leader(i->next, ab);
break;
default:
if(i->branch != nil){
leader(i->branch, ab);
leader(i->next, ab);
}
break;
}
}
firstb = lastb = mkblock(nil);
for(i = in; i != nil; i = i->next){
if(i->pc != 0){
b = findb(i, ab);
b->prev = lastb;
lastb->next = b;
if(canfallthrough(lastb->last))
predsucc(lastb, b);
lastb = b;
}
else
lastb->last = i;
switch(i->op){
case IGOTO:
case ICASE:
case ICASEL:
case ICASEC:
case INOOP:
if(i->op == INOOP && i->branch != nil){
b = findb(i->next, ab);
predsucc(lastb, b);
b = findb(i->branch, ab);
predsucc(lastb, b);
break;
}
b = findb(i->d.decl->ty->cse->iwild, ab);
predsucc(lastb, b);
lab = i->d.decl->ty->cse->labs;
n = i->d.decl->ty->cse->nlab;
for(j = 0; j < n; j++){
b = findb(lab[j].inst, ab);
predsucc(lastb, b);
}
break;
case IRET:
case IEXIT:
case IRAISE:
break;
case IJMP:
b = findb(i->branch, ab);
predsucc(lastb, b);
break;
default:
if(i->branch != nil){
b = findb(i->next, ab);
predsucc(lastb, b);
b = findb(i->branch, ab);
predsucc(lastb, b);
}
break;
}
}
*nb = ab->n;
free(ab->a);
free(ab);
b = firstb->next;
b->prev = nil;
return b;
}
static int
back(Block *b1, Block *b2)
{
return b1->dfn >= b2->dfn;
}
static void
pblocks(Block *b, int nb)
{
Inst *i;
Blist *bl;
print("--------------------%d blocks--------------------\n", nb);
print("------------------------------------------------\n");
for( ; b != nil; b = b->next){
print("dfn=%d\n", b->dfn);
print(" pred ");
for(bl = b->pred; bl != nil; bl = bl->next)
print("%d%s ", bl->block->dfn, back(bl->block, b) ? "*" : "");
print("\n");
print(" succ ");
for(bl = b->succ; bl != nil; bl = bl->next)
print("%d%s ", bl->block->dfn, back(b, bl->block) ? "*" : "");
print("\n");
for(i = b->first; i != nil; i = i->next){
// print(" %I\n", i);
pins(i);
if(i == b->last)
break;
}
}
print("------------------------------------------------\n");
}
static void
ckblocks(Inst *in, Block *b, int nb)
{
int n;
Block *lastb;
if(b->first != in)
fatal("A - %d", b->dfn);
n = 0;
lastb = nil;
for( ; b != nil; b = b->next){
n++;
if(b->prev != lastb)
fatal("a - %d\n", b->dfn);
if(b->prev != nil && b->prev->next != b)
fatal("b - %d\n", b->dfn);
if(b->next != nil && b->next->prev != b)
fatal("c - %d\n", b->dfn);
if(b->prev != nil && b->prev->last->next != b->first)
fatal("B - %d\n", b->dfn);
if(b->next != nil && b->last->next != b->next->first)
fatal("C - %d\n", b->dfn);
if(b->next == nil && b->last->next != nil)
fatal("D - %d\n", b->dfn);
if(b->last->branch != nil && b->succ->block->first != b->last->branch)
fatal("0 - %d\n", b->dfn);
lastb = b;
}
if(n != nb)
fatal("N - %d %d\n", n, nb);
}
static void
dfs0(Block *b, int *n)
{
Block *s;
Blist *bl;
b->flags = 1;
for(bl = b->succ; bl != nil; bl = bl->next){
s = bl->block;
if(s->flags == 0)
dfs0(s, n);
}
b->dfn = --(*n);
}
static int
dfs(Block *b, int nb)
{
int n, u;
Block *b0;
b0 = b;
n = nb;
dfs0(b0, &n);
u = 0;
for(b = b0; b != nil; b = b->next){
if(b->flags == 0){ /* unreachable: see foldbranch */
fatal("found unreachable code");
u++;
b->prev->next = b->next;
if(b->next){
b->next->prev = b->prev;
b->prev->last->next = b->next->first;
}
else
b->prev->last->next = nil;
}
b->flags = 0;
}
if(u){
for(b = b0; b != nil; b = b->next)
b->dfn -= u;
}
return nb-u;
}
static void
loop0(Block *b)
{
Block *p;
Blist *bl;
b->flags = 1;
for(bl = b->pred; bl != nil; bl = bl->next){
p = bl->block;
if(p->flags == 0)
loop0(p);
}
}
/* b1->b2 a back edge */
static void
loop(Block *b, Block *b1, Block *b2)
{
if(0 && debug['o'])
print("back edge %d->%d\n", b1->dfn, b2->dfn);
b2->flags = 1;
if(b1->flags == 0)
loop0(b1);
if(0 && debug['o'])
print(" loop ");
for( ; b != nil; b = b->next){
if(b->flags && 0 && debug['o'])
print("%d ", b->dfn);
b->flags = 0;
}
if(0 && debug['o'])
print("\n");
}
static void
loops(Block *b)
{
Block *b0;
Blist *bl;
b0 = b;
for( ; b != nil; b = b->next){
for(bl = b->succ; bl != nil; bl = bl->next){
if(back(b, bl->block))
loop(b0, b, bl->block);
}
}
}
static int
imm(int m, Addr *a)
{
if(m == Aimm)
return a->offset;
fatal("bad immediate value");
return -1;
}
static int
desc(int m, Addr *a)
{
if(m == Adesc)
return a->decl->desc->size;
fatal("bad descriptor value");
return -1;
}
static int
fpoff(int m, Addr *a)
{
int off;
Decl *d;
if(m == Afp || m == Afpind){
off = a->reg;
if((d = a->decl) != nil)
off += d->offset;
return off;
}
return -1;
}
static int
size(Inst *i)
{
switch(i->op){
case ISEND:
case IRECV:
case IALT:
case INBALT:
case ILEA:
return i->m.offset;
case IMOVM:
case IHEADM:
case ICONSM:
return imm(i->mm, &i->m);
case IMOVMP:
case IHEADMP:
case ICONSMP:
return desc(i->mm, &i->m);
break;
}
fatal("bad op in size");
return -1;
}
static Decl*
mkdec(int o)
{
Decl *d;
d = mkdecl(&nosrc, Dlocal, tint);
d->offset = o;
return d;
}
static void
mkdecls(void)
{
regdecls = mkdec(REGRET*IBY2WD);
regdecls->next = mkdec(STemp);
regdecls->next->next = mkdec(DTemp);
}
static Decl*
sharedecls(Decl *d)
{
Decl *ld;
ld = d;
for(d = d->next ; d != nil; d = d->next){
if(d->offset <= ld->offset)
break;
ld = d;
}
return d;
}
static int
finddec(int o, int s, Decl *vars, int *nv, Inst *i)
{
int m, n;
Decl *d;
n = 0;
for(d = vars; d != nil; d = d->next){
if(o >= d->offset && o < d->offset+d->ty->size){
m = 1;
while(o+s > d->offset+d->ty->size){
m++;
d = d->next;
}
*nv = m;
return n;
}
n++;
}
// print("%d %d missing\n", o, s);
pins(i);
fatal("missing decl");
return -1;
}
static void
setud(Bits *b, int id, int n, int pc)
{
if(id < 0)
return;
while(--n >= 0)
bset(b[id++], pc);
}
static void
ud(Inst *i, Decl *vars, Bits *uses, Bits *defs)
{
ushort f;
int id, j, nv, pc, sz, s, m, d, ss, sm, sd;
Optab *t;
Idlist *l;
pc = i->pc;
ss = 0;
t = &opflags[i->op];
f = t->flags;
sz = t->size;
s = fpoff(i->sm, &i->s);
m = fpoff(i->mm, &i->m);
d = fpoff(i->dm, &i->d);
if(f&Mduse && i->mm == Anone)
f |= Duse;
if(s >= 0){
if(i->sm == Afp){
ss = SS(sz);
if(ss == Mp)
ss = size(i);
}
else
ss = IBY2WD;
id = finddec(s, ss, vars, &nv, i);
if(f&Suse)
setud(uses, id, nv, pc);
if(f&Sdef){
if(i->sm == Afp)
setud(defs, id, nv, pc);
else
setud(uses, id, nv, pc);
}
}
if(m >= 0){
if(i->mm == Afp){
sm = SM(sz);
if(sm == Mp)
sm = size(i);
}
else
sm = IBY2WD;
id = finddec(m, sm, vars, &nv, i);
if(f&Muse)
setud(uses, id, nv, pc);
if(f&Mdef){
if(i->mm == Afp)
setud(defs, id, nv, pc);
else
setud(uses, id, nv, pc);
}
}
if(d >= 0){
if(i->dm == Afp){
sd = SD(sz);
if(sd == Mp)
sd = size(i);
}
else
sd = IBY2WD;
id = finddec(d, sd, vars, &nv, i);
if(f&Duse)
setud(uses, id, nv, pc);
if(f&Ddef){
if(i->dm == Afp)
setud(defs, id, nv, pc);
else
setud(uses, id, nv, pc);
}
}
if(f&Tuse1){
id = finddec(STemp, IBY2WD, vars, &nv, i);
setud(uses, id, nv, pc);
}
if(f&Tuse2){
id = finddec(DTemp, IBY2WD, vars, &nv, i);
setud(uses, id, nv, pc);
}
if(i->op == ILEA){
if(s >= 0){
id = finddec(s, ss, vars, &nv, i);
if(i->sm == Afp && i->m.reg == 0)
setud(defs, id, nv, pc);
else
setud(uses, id, nv, pc);
}
}
if(0)
switch(i->op){
case ILEA:
if(s >= 0){
id = finddec(s, ss, vars, &nv, i);
if(id < 0)
break;
for(j = 0; j < nv; j++){
if(i->sm == Afp && i->m.reg == 0)
addlist(&deflist, id++);
else
addlist(&uselist, id++);
}
}
break;
case IALT:
case INBALT:
case ICALL:
case IMCALL:
for(l = deflist; l != nil; l = l->next){
id = l->id;
bset(defs[id], pc);
}
for(l = uselist; l != nil; l = l->next){
id = l->id;
bset(uses[id], pc);
}
freelist(&deflist);
freelist(&uselist);
break;
}
}
static void
usedef(Inst *in, Decl *vars, Bits *uses, Bits *defs)
{
Inst *i;
for(i = in; i != nil; i = i->next)
ud(i, vars, uses, defs);
}
static void
pusedef(Bits *ud, int nv, Decl *d, char *s)
{
int i;
print("%s\n", s);
for(i = 0; i < nv; i++){
if(!bzero(ud[i])){
print("\t%s(%ld): ", decname(d), d->offset);
pbits(ud[i]);
print("\n");
}
d = d->next;
}
}
static void
dummydefs(Bits *defs, int nv, int npc)
{
int i;
for(i = 0; i < nv; i++)
bset(defs[i], npc++);
}
static void
dogenkill(Block *b, Bits *defs, int nv)
{
int i, n, t;
Bits v;
n = defs[0].n;
v = bnew(n, 0);
for( ; b != nil; b = b->next){
b->gen = bnew(n, 0);
b->kill = bnew(n, 0);
b->in = bnew(n, 0);
b->out = bnew(n, 0);
for(i = 0; i < nv; i++){
boper(Bclr, v, v);
bsets(v, b->first->pc, b->last->pc);
boper(Band, defs[i], v);
t = topbit(v);
if(t >= 0)
bset(b->gen, t);
else
continue;
boper(Bclr, v, v);
bsets(v, b->first->pc, b->last->pc);
boper(Binv, v, v);
boper(Band, defs[i], v);
boper(Bor, v, b->kill);
}
}
bfree(v);
}
static void
udflow(Block *b, int nv, int npc)
{
int iter;
Block *b0, *p;
Blist *bl;
Bits newin;
b0 = b;
for(b = b0; b != nil; b = b->next)
boper(Bstore, b->gen, b->out);
newin = bnew(b0->in.n, 0);
iter = 1;
while(iter){
iter = 0;
for(b = b0; b != nil; b = b->next){
boper(Bclr, newin, newin);
for(bl = b->pred; bl != nil; bl = bl->next){
p = bl->block;
boper(Bor, p->out, newin);
}
if(b == b0)
bsets(newin, npc, npc+nv-1);
if(!beq(b->in, newin))
iter = 1;
boper(Bstore, newin, b->in);
boper(Bstore, b->in, b->out);
boper(Bandrev, b->kill, b->out);
boper(Bor, b->gen, b->out);
}
}
bfree(newin);
}
static void
pflows(Block *b)
{
for( ; b != nil; b = b->next){
print("block %d\n", b->dfn);
print(" gen: "); pbits(b->gen); print("\n");
print(" kill: "); pbits(b->kill); print("\n");
print(" in: "); pbits(b->in); print("\n");
print(" out: "); pbits(b->out); print("\n");
}
}
static int
set(Decl *d)
{
if(d->store == Darg)
return 1;
if(d->sym == nil) /* || d->sym->name[0] == '.') */
return 1;
if(tattr[d->ty->kind].isptr || d->ty->kind == Texception)
return 1;
return 0;
}
static int
used(Decl *d)
{
if(d->sym == nil ) /* || d->sym->name[0] == '.') */
return 1;
return 0;
}
static void
udchain(Block *b, Decl *ds, int nv, int npc, Bits *defs, Bits *uses, Decl *sd)
{
int i, n, p, q;
Bits d, u, dd, ud;
Block *b0;
Inst *in;
b0 = b;
n = defs[0].n;
u = bnew(n, 0);
d = bnew(n, 0);
dd = bnew(n, 0);
ud = bnew(n, 0);
for(i = 0; i < nv; i++){
boper(Bstore, defs[i], ud);
bclr(ud, npc+i);
for(b = b0 ; b != nil; b = b->next){
boper(Bclr, u, u);
bsets(u, b->first->pc, b->last->pc);
boper(Band, uses[i], u);
boper(Bclr, d, d);
bsets(d, b->first->pc, b->last->pc);
boper(Band, defs[i], d);
for(;;){
p = topbit(u);
if(p < 0)
break;
bclr(u, p);
bclrs(d, p, -1);
q = topbit(d);
if(q >= 0){
bclr(ud, q);
if(debug['o'])
print("udc b=%d v=%d(%s/%ld) u=%d d=%d\n", b->dfn, i, decname(ds), ds->offset, p, q);
}
else{
boper(Bstore, defs[i], dd);
boper(Band, b->in, dd);
boper(Bandrev, dd, ud);
if(!bzero(dd)){
if(debug['o']){
print("udc b=%d v=%d(%s/%ld) u=%d d=", b->dfn, i, decname(ds), ds->offset, p);
pbits(dd);
print("\n");
}
if(bmem(dd, npc+i) && !set(ds))
warning(pc2i(b0, p), "used and not set", ds, sd);
}
else
fatal("no defs in udchain");
}
}
}
for(;;){
p = topbit(ud);
if(p < 0)
break;
bclr(ud, p);
if(!used(ds)){
in = pc2i(b0, p);
if(isnilsrc(&in->src)) /* nilling code */
in->op = INOOP; /* elim p from bitmaps ? */
else if(limbovar(ds) && !structure(ds->ty))
warning(in, "set and not used", ds, sd);
}
}
ds = ds->next;
}
bfree(u);
bfree(d);
bfree(dd);
bfree(ud);
}
static void
ckflags(void)
{
int i, j, k, n;
Optab *o;
n = nelem(opflags);
o = opflags;
for(i = 0; i < n; i++){
j = (o->flags&(Suse|Sdef)) != 0;
k = SS(o->size) != 0;
if(j != k){
if(!(j == 0 && k == 1 && i == ILEA))
fatal("S %ld %s\n", o-opflags, instname[i]);
}
j = (o->flags&(Muse|Mdef)) != 0;
k = SM(o->size) != 0;
if(j != k)
fatal("M %ld %s\n", o-opflags, instname[i]);
j = (o->flags&(Duse|Ddef)) != 0;
k = SD(o->size) != 0;
if(j != k){
if(!(j == 1 && k == 0 && (i == IGOTO || i == ICASE || i == ICASEC || i == ICASEL)))
fatal("D %ld %s\n", o-opflags, instname[i]);
}
o++;
}
}
void
optim(Inst *in, Decl *d)
{
int nb, npc, nv, nd, nu;
Block *b;
Bits *uses, *defs;
Decl *sd;
ckflags();
if(debug['o'])
print("************************************************\nfunction %s\n************************************************\n", d->sym->name);
if(in == nil || errors > 0)
return;
d = d->ty->ids;
if(regdecls == nil)
mkdecls();
regdecls->next->next->next = d;
d = regdecls;
sd = sharedecls(d);
if(debug['o'])
printdecls(d);
b = mkblocks(in, &nb);
ckblocks(in, b, nb);
npc = inspc(in);
nb = dfs(b, nb);
if(debug['o'])
pblocks(b, nb);
loops(b);
nv = len(d);
uses = allocbits(nv, npc+nv);
defs = allocbits(nv, npc+nv);
dummydefs(defs, nv, npc);
usedef(in, d, uses, defs);
if(debug['o']){
pusedef(uses, nv, d, "uses");
pusedef(defs, nv, d, "defs");
}
nu = bitcount(uses, nv);
nd = bitcount(defs, nv);
dogenkill(b, defs, nv);
udflow(b, nv, npc);
if(debug['o'])
pflows(b);
udchain(b, d, nv, npc, defs, uses, sd);
freeblks(b);
freebits(uses, nv);
freebits(defs, nv);
if(debug['o'])
print("nb=%d npc=%d nv=%d nd=%d nu=%d\n", nb, npc, nv, nd, nu);
}