ref: b5a6dc7849cbd9f1fd23183ba46f0d5deb24e81d
dir: /sys/src/cmd/2c/swt.c/
#include "gc.h"
int
swcmp(const void *a1, const void *a2)
{
C1 *p1, *p2;
p1 = (C1*)a1;
p2 = (C1*)a2;
if(p1->val < p2->val)
return -1;
return p1->val > p2->val;
}
void
doswit(int g, Node *n)
{
Case *c;
C1 *q, *iq;
long def, nc, i;
def = 0;
nc = 0;
for(c = cases; c->link != C; c = c->link) {
if(c->def) {
if(def)
diag(n, "more than one default in switch");
def = c->label;
continue;
}
nc++;
}
iq = alloc(nc*sizeof(C1));
q = iq;
for(c = cases; c->link != C; c = c->link) {
if(c->def)
continue;
q->label = c->label;
q->val = c->val;
q++;
}
qsort(iq, nc, sizeof(C1), swcmp);
if(def == 0)
def = breakpc;
for(i=0; i<nc-1; i++)
if(iq[i].val == iq[i+1].val)
diag(n, "duplicate cases in switch %lld", iq[i].val);
swit1(iq, nc, def, g, n);
}
#define N1 4 /* ncase: always linear */
#define N2 5 /* min ncase: direct */
#define N3 4 /* range/ncase: direct */
/* else binary */
void
swit1(C1 *q, int nc, long def, int g, Node *n)
{
C1 *r, *s;
int i, l, m, y;
long v, range;
Prog *sp1, *sp2;
/* note that g and g+1 are not allocated */
if(nc <= N1)
goto linear;
y = 23*nc/100 + 5; /* number of cases needed to make */
if(y < N2) /* direct switch worthwile */
y = N2; /* try to do better than n**2 here */
for(m=nc; m>=y; m--) { /* m is number of cases */
s = q+nc;
r = s-m;
for(l=nc-m; l>=0; l--) { /* l is base of contig cases */
s--;
range = s->val - r->val;
if(range > 0 && range <= N3*m)
goto direct;
r--;
}
}
/*
* divide and conquer
*/
i = nc / 2;
r = q+i;
v = r->val;
/* compare median */
if(v >= -128 && v < 128) {
gopcode(OAS, n->type, D_CONST, nodconst(v), g+1, n);
gopcode(OEQ, n->type, g, n, g+1, n);
} else
gopcode(OEQ, n->type, g, n, D_CONST, nodconst(v));
gbranch(OLT);
sp1 = p;
gbranch(OGT);
sp2 = p;
gbranch(OGOTO);
patch(p, r->label);
patch(sp1, pc);
swit1(q, i, def, g, n);
patch(sp2, pc);
swit1(r+1, nc-i-1, def, g, n);
return;
direct:
/* compare low bound */
v = r->val;
if(v >= -128 && v < 128) {
gopcode(OAS, n->type, D_CONST, nodconst(v), g+1, n);
gopcode(OEQ, n->type, g, n, g+1, n);
} else
gopcode(OEQ, n->type, g, n, D_CONST, nodconst(v));
gbranch(OLT);
sp1 = p;
/* compare high bound */
v = s->val;
if(v >= -128 && v < 128) {
gopcode(OAS, n->type, D_CONST, nodconst(v), g+1, n);
gopcode(OEQ, n->type, g, n, g+1, n);
} else
gopcode(OEQ, n->type, g, n, D_CONST, nodconst(v));
gbranch(OGT);
sp2 = p;
/* switch */
v = r->val;
gpseudo(AMOVW, symstatic, D_R0, 0L);
p->from.offset = nstatic - v*2;
p->from.index = g|I_INDEX1;
p->from.scale = 5;
nextpc();
p->as = ACASEW;
/* table */
for(i=0; i<=range; i++) {
gbranch(OCASE);
if(v == r->val) {
patch(p, r->label);
r++;
} else
patch(p, def);
p->from.type = D_STATIC;
p->from.sym = symstatic;
p->from.offset = nstatic;
nstatic += types[TSHORT]->width;
v++;
}
gbranch(OGOTO);
patch(p, def);
if(r != s+1)
print("smelly direct switch\n");
if(l > 0) {
patch(sp1, pc);
swit1(q, l, def, g, n);
} else
patch(sp1, def);
m += l;
if(m < nc) {
patch(sp2, pc);
swit1(q+m, nc-m, def, g, n);
} else
patch(sp2, def);
return;
linear:
for(i=0; i<nc; i++) {
v = q->val;
if(v >= -128 && v < 128) {
gopcode(OAS, n->type, D_CONST, nodconst(v), g+1, n);
gopcode(OEQ, n->type, g+1, n, g, n);
} else
gopcode(OEQ, n->type, g, n, D_CONST, nodconst(v));
gbranch(OEQ);
patch(p, q->label);
q++;
}
gbranch(OGOTO);
patch(p, def);
}
void
casf(void)
{
Case *c;
c = alloc(sizeof(*c));
c->link = cases;
cases = c;
}
int
bitload(Node *b, int n1, int n2, int n3, Node *nn)
{
int sh, g, gs;
long v;
Node *l;
Type *t;
/*
* n1 gets adjusted/masked value
* n2 gets address of cell
* n3 gets contents of cell
*/
gs = 0;
t = tfield;
l = b->left;
g = regalloc(t, n3);
if(n2 != D_NONE) {
lcgen(l, n2, Z);
n2 |= I_INDIR;
gmove(t, t, n2, l, g, l);
gmove(t, t, g, l, n1, l);
} else
cgen(l, g, nn);
if(b->type->shift == 0 && typeu[b->type->etype]) {
v = ~0 + (1L << b->type->nbits);
gopcode(OAND, t, D_CONST, nodconst(v), g, l);
} else {
sh = 32 - b->type->shift - b->type->nbits;
if(sh > 0)
if(sh >= 8) {
gs = regalloc(t, D_NONE);
gmove(t, t, D_CONST, nodconst(sh), gs, l);
gopcode(OASHL, t, gs, l, g, l);
if(b->type->shift)
regfree(gs);
} else
gopcode(OASHL, t, D_CONST, nodconst(sh), g, l);
sh += b->type->shift;
if(sh > 0) {
if(sh >= 8) {
if(b->type->shift) {
gs = regalloc(t, D_NONE);
gmove(t, t, D_CONST, nodconst(sh), gs, l);
}
if(typeu[b->type->etype])
gopcode(OLSHR, t, gs, l, g, l);
else
gopcode(OASHR, t, gs, l, g, l);
regfree(gs);
} else {
if(typeu[b->type->etype])
gopcode(OLSHR, t, D_CONST, nodconst(sh), g, l);
else
gopcode(OASHR, t, D_CONST, nodconst(sh), g, l);
}
}
}
return g;
}
void
bitstore(Node *b, int n1, int n2, int n3, int result, Node *nn)
{
long v;
Node *l;
Type *t;
int sh, g, gs;
/*
* n1 has adjusted/masked value
* n2 has address of cell
* n3 has contents of cell
*/
t = tfield;
l = b->left;
g = regalloc(t, D_NONE);
v = ~0 + (1L << b->type->nbits);
gopcode(OAND, t, D_CONST, nodconst(v), n1, l);
gmove(t, t, n1, l, g, l);
if(result != D_NONE)
gmove(t, nn->type, n1, l, result, nn);
sh = b->type->shift;
if(sh > 0) {
if(sh >= 8) {
gs = regalloc(t, D_NONE);
gmove(t, t, D_CONST, nodconst(sh), gs, l);
gopcode(OASHL, t, gs, l, g, l);
regfree(gs);
} else
gopcode(OASHL, t, D_CONST, nodconst(sh), g, l);
}
v <<= sh;
gopcode(OAND, t, D_CONST, nodconst(~v), n3, l);
gopcode(OOR, t, n3, l, g, l);
gmove(t, t, g, l, n2|I_INDIR, l);
regfree(g);
regfree(n1);
regfree(n2);
regfree(n3);
}
long
outstring(char *s, long n)
{
long r;
if(suppress)
return nstring;
r = nstring;
while(n) {
string[mnstring] = *s++;
mnstring++;
nstring++;
if(mnstring >= NSNAME) {
gpseudo(ADATA, symstring, D_SCONST, 0L);
memmove(p->to.sval, string, NSNAME);
p->from.offset = nstring - NSNAME;
p->from.displace = NSNAME;
mnstring = 0;
}
n--;
}
return r;
}
long
outlstring(Rune *s, long n)
{
char buf[sizeof(Rune)];
int c, i;
long r;
while(nstring % sizeof buf)
outstring("", 1);
r = nstring;
while(n > 0) {
c = *s++;
if(align(0, types[TCHAR], Aarg1)) {
for(i = sizeof buf; i > 0; c >>= 8)
buf[--i] = c;
} else {
for(i = 0; i < sizeof buf; c >>= 8)
buf[i++] = c;
}
outstring(buf, sizeof buf);
n -= sizeof buf;
}
return r;
}
int
doinc(Node *n, int f)
{
Node *l;
int a;
loop:
if(n == Z)
return 0;
l = n->left;
switch(n->op) {
case OPOSTINC:
case OPOSTDEC:
if(f & POST) {
a = n->addable;
if(a >= INDEXED) {
if(f & TEST)
return 1;
n->addable = 0;
cgen(n, D_NONE, n);
n->addable = a;
}
}
break;
case OAS:
case OASLMUL:
case OASLDIV:
case OASLMOD:
case OASMUL:
case OASDIV:
case OASMOD:
case OASXOR:
case OASOR:
case OASADD:
case OASSUB:
case OASLSHR:
case OASASHR:
case OASASHL:
case OASAND:
case OPREINC:
case OPREDEC:
if(f & PRE) {
a = n->addable;
if(a >= INDEXED) {
if(f & TEST)
return 1;
n->addable = 0;
doinc(n, PRE);
cgen(n, D_NONE, n);
n->addable = a;
return 0;
}
}
break;
case OFUNC:
if(f & PRE)
break;
return 0;
case ONAME:
case OREGISTER:
case OSTRING:
case OCONST:
case OANDAND:
case OOROR:
return 0;
case OCOND:
return 0;
case OCOMMA:
n = n->right;
if(f & PRE)
n = l;
goto loop;
}
if(l != Z)
if(doinc(l, f))
return 1;
n = n->right;
goto loop;
}
void
setsp(void)
{
nextpc();
p->as = AADJSP;
p->from.type = D_CONST;
p->from.offset = 0;
}
void
adjsp(long o)
{
if(o != 0) {
nextpc();
p->as = AADJSP;
p->from.type = D_CONST;
p->from.offset = o;
argoff += o;
}
}
int
simplv(Node *n)
{
if(n->addable <= INDEXED)
return 0;
while(n->op == OIND)
n = n->left;
if(n->op == ONAME)
return 1;
return 0;
}
int
eval(Node *n, int g)
{
if(n->addable >= INDEXED)
return D_TREE;
g = regalloc(n->type, g);
cgen(n, g, n);
return g;
}
void outhist(Biobuf*);
void zname(Biobuf*, Sym*, int);
void zaddr(Biobuf*, Adr*, int);
void zwrite(Biobuf*, Prog*, int, int);
void
outcode(void)
{
struct { Sym *sym; short type; } h[NSYM];
Prog *p;
Sym *s;
int f, sf, st, t, sym;
Biobuf b;
if(debug['S']) {
for(p = firstp; p != P; p = p->link)
if(p->as != ADATA && p->as != AGLOBL)
pc--;
for(p = firstp; p != P; p = p->link) {
print("%P\n", p);
if(p->as != ADATA && p->as != AGLOBL)
pc++;
}
}
f = open(outfile, OWRITE);
if(f < 0) {
diag(Z, "cant open %s", outfile);
errorexit();
}
Binit(&b, f, OWRITE);
Bseek(&b, 0L, 2);
outhist(&b);
for(sym=0; sym<NSYM; sym++) {
h[sym].sym = S;
h[sym].type = 0;
}
sym = 1;
for(p = firstp; p != P; p = p->link) {
jackpot:
sf = 0;
s = p->from.sym;
while(s != S) {
sf = s->sym;
if(sf < 0 || sf >= NSYM)
sf = 0;
t = p->from.type & D_MASK;
if(h[sf].type == t)
if(h[sf].sym == s)
break;
s->sym = sym;
zname(&b, s, t);
h[sym].sym = s;
h[sym].type = t;
sf = sym;
sym++;
if(sym >= NSYM)
sym = 1;
break;
}
st = 0;
s = p->to.sym;
while(s != S) {
st = s->sym;
if(st < 0 || st >= NSYM)
st = 0;
t = p->to.type & D_MASK;
if(h[st].type == t)
if(h[st].sym == s)
break;
s->sym = sym;
zname(&b, s, t);
h[sym].sym = s;
h[sym].type = t;
st = sym;
sym++;
if(sym >= NSYM)
sym = 1;
if(st == sf)
goto jackpot;
break;
}
zwrite(&b, p, sf, st);
}
Bflush(&b);
close(f);
firstp = P;
lastp = P;
}
void
zwrite(Biobuf *b, Prog *p, int sf, int st)
{
long l;
l = p->as;
Bputc(b, l);
Bputc(b, l>>8);
l = p->lineno;
Bputc(b, l);
Bputc(b, l>>8);
Bputc(b, l>>16);
Bputc(b, l>>24);
zaddr(b, &p->from, sf);
zaddr(b, &p->to, st);
}
void
zname(Biobuf *b, Sym *s, int t)
{
char *n;
ulong sig;
if(debug['T'] && t == D_EXTERN && s->sig != SIGDONE && s->type != types[TENUM] && s != symrathole){
sig = sign(s);
Bputc(b, ASIGNAME);
Bputc(b, ASIGNAME>>8);
Bputc(b, sig);
Bputc(b, sig>>8);
Bputc(b, sig>>16);
Bputc(b, sig>>24);
s->sig = SIGDONE;
}
else{
Bputc(b, ANAME); /* as */
Bputc(b, ANAME>>8); /* as */
}
Bputc(b, t); /* type */
Bputc(b, s->sym); /* sym */
n = s->name;
while(*n) {
Bputc(b, *n);
n++;
}
Bputc(b, 0);
}
void
zaddr(Biobuf *b, Adr *a, int s)
{
long l;
int i, t;
char *n;
Ieee e;
t = 0;
if(a->field)
t |= T_FIELD;
if(a->index != D_NONE)
t |= T_INDEX;
if(s)
t |= T_SYM;
switch(a->type) {
default:
if(a->offset)
t |= T_OFFSET;
if(a->displace)
t |= T_INDEX;
if(a->type & ~0xff)
t |= T_TYPE;
break;
case D_FCONST:
t |= T_FCONST;
break;
case D_SCONST:
t |= T_SCONST;
break;
}
Bputc(b, t);
if(t & T_FIELD) { /* implies field */
i = a->field;
Bputc(b, i);
Bputc(b, i>>8);
}
if(t & T_INDEX) { /* implies index, scale, displace */
i = a->index;
Bputc(b, i);
Bputc(b, i>>8);
Bputc(b, a->scale);
l = a->displace;
Bputc(b, l);
Bputc(b, l>>8);
Bputc(b, l>>16);
Bputc(b, l>>24);
}
if(t & T_OFFSET) { /* implies offset */
l = a->offset;
Bputc(b, l);
Bputc(b, l>>8);
Bputc(b, l>>16);
Bputc(b, l>>24);
}
if(t & T_SYM) /* implies sym */
Bputc(b, s);
if(t & T_FCONST) {
ieeedtod(&e, a->dval);
l = e.l;
Bputc(b, l);
Bputc(b, l>>8);
Bputc(b, l>>16);
Bputc(b, l>>24);
l = e.h;
Bputc(b, l);
Bputc(b, l>>8);
Bputc(b, l>>16);
Bputc(b, l>>24);
return;
}
if(t & T_SCONST) {
n = a->sval;
for(i=0; i<NSNAME; i++) {
Bputc(b, *n);
n++;
}
return;
}
i = a->type;
Bputc(b, i);
if(t & T_TYPE)
Bputc(b, i>>8);
}
void
outhist(Biobuf *b)
{
Hist *h;
char *p, *q, *op, c;
Prog pg;
int n;
pg = zprog;
pg.as = AHISTORY;
c = pathchar();
for(h = hist; h != H; h = h->link) {
p = h->name;
op = 0;
/* on windows skip drive specifier in pathname */
if(systemtype(Windows) && p && p[1] == ':'){
p += 2;
c = *p;
}
if(p && p[0] != c && h->offset == 0 && pathname){
/* on windows skip drive specifier in pathname */
if(systemtype(Windows) && pathname[1] == ':') {
op = p;
p = pathname+2;
c = *p;
} else if(pathname[0] == c){
op = p;
p = pathname;
}
}
while(p) {
q = utfrune(p, c);
if(q) {
n = q-p;
if(n == 0){
n = 1; /* leading "/" */
*p = '/'; /* don't emit "\" on windows */
}
q++;
} else {
n = strlen(p);
q = 0;
}
if(n) {
Bputc(b, ANAME);
Bputc(b, ANAME>>8);
Bputc(b, D_FILE);
Bputc(b, 1);
Bputc(b, '<');
Bwrite(b, p, n);
Bputc(b, 0);
}
p = q;
if(p == 0 && op) {
p = op;
op = 0;
}
}
pg.lineno = h->line;
pg.to.type = zprog.to.type;
pg.to.offset = h->offset;
if(h->offset)
pg.to.type = D_CONST;
zwrite(b, &pg, 0, 0);
}
}
void
ieeedtod(Ieee *ieee, double native)
{
double fr, ho, f;
int exp;
if(native < 0) {
ieeedtod(ieee, -native);
ieee->h |= 0x80000000L;
return;
}
if(native == 0) {
ieee->l = 0;
ieee->h = 0;
return;
}
fr = frexp(native, &exp);
f = 2097152L; /* shouldnt use fp constants here */
fr = modf(fr*f, &ho);
ieee->h = ho;
ieee->h &= 0xfffffL;
ieee->h |= (exp+1022L) << 20;
f = 65536L;
fr = modf(fr*f, &ho);
ieee->l = ho;
ieee->l <<= 16;
ieee->l |= (long)(fr*f);
}
int
nodalloc(Type *t, int g, Node *n)
{
n->type = t;
n->op = OREGISTER;
n->addable = 12;
n->complex = 0;
g = regaddr(g);
n->reg = g | I_INDIR;
n->xoffset = 0;
return g;
}
int
mulcon(Node *n, Node *c, int result, Node *nn)
{
long v;
if(typefd[n->type->etype])
return 0;
v = c->vconst;
if(mulcon1(n, v, result, nn))
return 1;
return 0;
}
int
shlcon(Node *n, Node *c, int result, Node *nn)
{
long v;
v = 1L << c->vconst;
return mulcon1(n, v, result, nn);
}
int
mulcon1(Node *n, long v, int result, Node *nn)
{
int g, g1, a1, a2, neg;
int o;
char code[10], *p;
if(result == D_NONE)
return 0;
neg = 0;
if(v < 0) {
v = -v;
neg++;
}
a1 = 0;
a2 = multabsize;
for(;;) {
if(a1 >= a2)
return 0;
g1 = (a2 + a1)/2;
if(v < multab[g1].val) {
a2 = g1;
continue;
}
if(v > multab[g1].val) {
a1 = g1+1;
continue;
}
break;
}
strcpy(code, "0");
strncat(code, multab[g1].code, sizeof(multab[0].code));
p = code;
if(p[1] == 'i')
p += 2;
g = regalloc(n->type, result);
cgen(n, g, n);
if(neg)
gopcode(ONEG, n->type, D_NONE, n, g, n);
g1 = regalloc(n->type, D_NONE);
loop:
switch(*p) {
case 0:
regfree(g1);
gmove(n->type, nn->type, g, n, result, nn);
regfree(g);
return 1;
case '0':
o = OAS;
*p -= '0';
goto com;
case '1':
case '2':
o = OSUB;
*p -= '1';
goto com;
case '3':
case '4':
case '5':
case '6':
o = OADD;
*p -= '3';
com:
a1 = g;
if(*p == 1 || *p == 3)
a1 = g1;
a2 = g;
if(*p == 0 || *p == 3)
a2 = g1;
gopcode(o, n->type, a1, n, a2, n);
p++;
break;
default:
a1 = *p++ - 'a' + 1;
a2 = g;
if(a1 > 8) {
a2 = g1;
a1 -= 8;
}
gopcode(OASHL, n->type, D_CONST, nodconst(a1), a2, n);
break;
}
goto loop;
}
void
nullwarn(Node *l, Node *r)
{
warn(Z, "result of operation not used");
if(l != Z)
cgen(l, D_NONE, Z);
if(r != Z)
cgen(r, D_NONE, Z);
}
void
sextern(Sym *s, Node *a, long o, long w)
{
long e, lw;
for(e=0; e<w; e+=NSNAME) {
lw = NSNAME;
if(w-e < lw)
lw = w-e;
gpseudo(ADATA, s, D_SCONST, 0L);
p->from.offset += o+e;
p->from.displace = lw;
memmove(p->to.sval, a->cstring+e, lw);
}
}
void
gextern(Sym *s, Node *a, long o, long w)
{
if(a->op == OCONST && typev[a->type->etype]) {
gpseudo(ADATA, s, D_CONST, (long)(a->vconst>>32));
p->from.offset += o;
p->from.displace = 4;
gpseudo(ADATA, s, D_CONST, (long)(a->vconst));
p->from.offset += o + 4;
p->from.displace = 4;
return;
}
gpseudotree(ADATA, s, a);
p->from.offset += o;
p->from.displace = w;
}
long
align(long i, Type *t, int op)
{
long o;
Type *v;
int w;
o = i;
w = 1;
switch(op) {
default:
diag(Z, "unknown align opcode %d", op);
break;
case Asu2: /* padding at end of a struct */
w = SZ_LONG;
if(packflg)
w = packflg;
break;
case Ael1: /* initial allign of struct element */
for(v=t; v->etype==TARRAY; v=v->link)
;
w = ewidth[v->etype];
if(w <= 0 || w >= SZ_SHORT)
w = SZ_SHORT;
if(packflg)
w = packflg;
break;
case Ael2: /* width of a struct element */
o += t->width;
break;
case Aarg0: /* initial passbyptr argument in arg list */
if(typesuv[t->etype]) {
o = align(o, types[TIND], Aarg1);
o = align(o, types[TIND], Aarg2);
}
break;
case Aarg1: /* initial allign of parameter */
w = ewidth[t->etype];
if(w <= 0 || w >= SZ_LONG) {
w = SZ_LONG;
break;
}
o += SZ_LONG - w; /* big endian adjustment */
w = 1;
break;
case Aarg2: /* width of a parameter */
o += t->width;
w = SZ_LONG;
break;
case Aaut3: /* total allign of automatic */
o = align(o, t, Ael1);
o = align(o, t, Ael2);
break;
}
o = round(o, w);
if(debug['A'])
print("align %s %ld %T = %ld\n", bnames[op], i, t, o);
return o;
}
long
maxround(long max, long v)
{
v += SZ_LONG-1;
if(v > max)
max = round(v, SZ_LONG);
return max;
}