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gen.c
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gen.c
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// Copyright 2009 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
#undef EXTERN
#define EXTERN
#include "gg.h"
#include "opt.h"
void
compile(Node *fn)
{
Plist *pl;
Node nod1;
Prog *ptxt;
int32 lno;
Type *t;
Iter save;
if(newproc == N) {
newproc = nod(ONAME, N, N);
newproc->sym = pkglookup("newproc", "sys");
newproc->class = PEXTERN;
newproc->addable = 1;
newproc->ullman = 1;
}
if(throwindex == N) {
throwindex = nod(ONAME, N, N);
throwindex->sym = pkglookup("throwindex", "sys");
throwindex->class = PEXTERN;
throwindex->addable = 1;
throwindex->ullman = 1;
}
if(throwreturn == N) {
throwreturn = nod(ONAME, N, N);
throwreturn->sym = pkglookup("throwreturn", "sys");
throwreturn->class = PEXTERN;
throwreturn->addable = 1;
throwreturn->ullman = 1;
}
if(fn->nbody == N)
return;
// set up domain for labels
labellist = L;
lno = setlineno(fn);
curfn = fn;
dowidth(curfn->type);
if(curfn->type->outnamed) {
// add clearing of the output parameters
t = structfirst(&save, getoutarg(curfn->type));
while(t != T) {
if(t->nname != N && t->nname->sym->name[0] != '_') {
curfn->nbody = list(nod(OAS, t->nname, N), curfn->nbody);
}
t = structnext(&save);
}
}
walk(curfn);
if(nerrors != 0)
goto ret;
allocparams();
continpc = P;
breakpc = P;
pl = newplist();
pl->name = curfn->nname;
pl->locals = autodcl;
nodconst(&nod1, types[TINT32], 0);
ptxt = gins(ATEXT, curfn->nname, &nod1);
// inarggen();
ginit();
gen(curfn->nbody, L);
gclean();
checklabels();
if(curfn->type->outtuple != 0) {
gins(ACALL, N, throwreturn);
}
pc->as = ARET; // overwrite AEND
pc->lineno = lineno;
if(!debug['N'] || debug['R'] || debug['P'])
regopt(ptxt);
// fill in argument size
ptxt->to.offset = rnd(curfn->type->argwid, maxround);
// fill in final stack size
ptxt->to.offset <<= 32;
ptxt->to.offset |= rnd(stksize+maxarg, maxround);
if(debug['f'])
frame(0);
ret:
lineno = lno;
}
void
allocparams(void)
{
Dcl *d;
Node *n;
uint32 w;
/*
* allocate (set xoffset) the stack
* slots for all automatics.
* allocated starting at -w down.
*/
for(d=autodcl; d!=D; d=d->forw) {
if(d->op != ONAME)
continue;
n = d->dnode;
if(n->class != PAUTO)
continue;
dowidth(n->type);
w = n->type->width;
stksize += w;
stksize = rnd(stksize, w);
n->xoffset = -stksize;
}
}
/*
* compile statements
*/
void
gen(Node *n, Label *labloop)
{
int32 lno;
Prog *scontin, *sbreak;
Prog *p1, *p2, *p3;
Node *l;
Label *lab;
lno = setlineno(n);
loop:
if(n == N)
goto ret;
if(n->ninit)
gen(n->ninit, L);
setlineno(n);
switch(n->op) {
default:
fatal("gen: unknown op %N", n);
break;
case OLIST:
l = n->left;
gen(l, L);
if(l != N && l->op == OLABEL) {
// call the next statement with a label
l = n->right;
if(l != N) {
if(l->op != OLIST) {
gen(l, labellist);
break;
}
gen(l->left, labellist);
n = l->right;
labloop = L;
goto loop;
}
}
n = n->right;
labloop = L;
goto loop;
case OPANIC:
genpanic();
break;
case OCASE:
case OFALL:
case OXCASE:
case OXFALL:
case OEMPTY:
break;
case OLABEL:
lab = mal(sizeof(*lab));
lab->link = labellist;
labellist = lab;
lab->sym = n->left->sym;
lab->op = OLABEL;
lab->label = pc;
break;
case OGOTO:
lab = mal(sizeof(*lab));
lab->link = labellist;
labellist = lab;
lab->sym = n->left->sym;
lab->op = OGOTO;
lab->label = pc;
gbranch(AJMP, T);
break;
case OBREAK:
if(n->left != N) {
lab = findlab(n->left->sym);
if(lab == L || lab->breakpc == P) {
yyerror("break label is not defined: %S", n->left->sym);
break;
}
patch(gbranch(AJMP, T), lab->breakpc);
break;
}
if(breakpc == P) {
yyerror("break is not in a loop");
break;
}
patch(gbranch(AJMP, T), breakpc);
break;
case OCONTINUE:
if(n->left != N) {
lab = findlab(n->left->sym);
if(lab == L || lab->continpc == P) {
yyerror("continue label is not defined: %S", n->left->sym);
break;
}
patch(gbranch(AJMP, T), lab->continpc);
break;
}
if(continpc == P) {
yyerror("gen: continue is not in a loop");
break;
}
patch(gbranch(AJMP, T), continpc);
break;
case OFOR:
p1 = gbranch(AJMP, T); // goto test
sbreak = breakpc;
breakpc = gbranch(AJMP, T); // break: goto done
scontin = continpc;
continpc = pc;
gen(n->nincr, L); // contin: incr
patch(p1, pc); // test:
if(n->ntest != N)
if(n->ntest->ninit != N)
gen(n->ntest->ninit, L);
bgen(n->ntest, 0, breakpc); // if(!test) goto break
if(labloop != L) {
labloop->op = OFOR;
labloop->continpc = continpc;
labloop->breakpc = breakpc;
}
gen(n->nbody, L); // body
patch(gbranch(AJMP, T), continpc); // goto contin
patch(breakpc, pc); // done:
continpc = scontin;
breakpc = sbreak;
break;
case OIF:
p1 = gbranch(AJMP, T); // goto test
p2 = gbranch(AJMP, T); // p2: goto else
patch(p1, pc); // test:
if(n->ntest != N)
if(n->ntest->ninit != N)
gen(n->ntest->ninit, L);
bgen(n->ntest, 0, p2); // if(!test) goto p2
gen(n->nbody, L); // then
p3 = gbranch(AJMP, T); // goto done
patch(p2, pc); // else:
gen(n->nelse, L); // else
patch(p3, pc); // done:
break;
case OSWITCH:
p1 = gbranch(AJMP, T); // goto test
sbreak = breakpc;
breakpc = gbranch(AJMP, T); // break: goto done
patch(p1, pc); // test:
if(labloop != L) {
labloop->op = OFOR;
labloop->breakpc = breakpc;
}
swgen(n); // switch(test) body
patch(breakpc, pc); // done:
breakpc = sbreak;
break;
case OSELECT:
sbreak = breakpc;
p1 = gbranch(AJMP, T); // goto test
breakpc = gbranch(AJMP, T); // break: goto done
patch(p1, pc); // test:
if(labloop != L) {
labloop->op = OFOR;
labloop->breakpc = breakpc;
}
gen(n->nbody, L); // select() body
patch(breakpc, pc); // done:
breakpc = sbreak;
break;
case OASOP:
cgen_asop(n);
break;
case OAS:
cgen_as(n->left, n->right);
break;
case OCALLMETH:
cgen_callmeth(n, 0);
break;
case OCALLINTER:
cgen_callinter(n, N, 0);
break;
case OCALL:
cgen_call(n, 0);
break;
case OPROC:
cgen_proc(n);
break;
case ORETURN:
cgen_ret(n);
break;
}
ret:
lineno = lno;
}
Case*
csort(Case *l, int(*f)(Case*, Case*))
{
Case *l1, *l2, *le;
if(l == 0 || l->slink == 0)
return l;
l1 = l;
l2 = l;
for(;;) {
l2 = l2->slink;
if(l2 == 0)
break;
l2 = l2->slink;
if(l2 == 0)
break;
l1 = l1->slink;
}
l2 = l1->slink;
l1->slink = 0;
l1 = csort(l, f);
l2 = csort(l2, f);
/* set up lead element */
if((*f)(l1, l2) < 0) {
l = l1;
l1 = l1->slink;
} else {
l = l2;
l2 = l2->slink;
}
le = l;
for(;;) {
if(l1 == 0) {
while(l2) {
le->slink = l2;
le = l2;
l2 = l2->slink;
}
le->slink = 0;
break;
}
if(l2 == 0) {
while(l1) {
le->slink = l1;
le = l1;
l1 = l1->slink;
}
break;
}
if((*f)(l1, l2) < 0) {
le->slink = l1;
le = l1;
l1 = l1->slink;
} else {
le->slink = l2;
le = l2;
l2 = l2->slink;
}
}
le->slink = 0;
return l;
}
int
casecmp(Case *c1, Case *c2)
{
int w;
w = whatis(c1->scase);
if(w != whatis(c2->scase))
fatal("casecmp1");
switch(w) {
case Wlitfloat:
return mpcmpfltflt(c1->scase->val.u.fval, c2->scase->val.u.fval);
case Wlitint:
return mpcmpfixfix(c1->scase->val.u.xval, c2->scase->val.u.xval);
case Wlitstr:
return cmpslit(c1->scase, c2->scase);
// case Wlitbool:
// case Wlitnil:
}
fatal("casecmp2");
return 0;
}
void
swconst(Case *sa, int nc, Node *n1, Node *tmp)
{
Case *s, *sb;
Prog *p1, *p2, *p3;
int n;
// small number of cases --
// test them sequentially
if(nc < 4) {
for(s=sa; s!=C; s=s->slink) {
setlineno(s->scase);
memset(n1, 0, sizeof(*n1));
n1->op = OEQ;
n1->left = tmp;
n1->right = s->scase;
walktype(n1, Erv);
bgen(n1, 1, s->sprog);
}
return;
}
// large number of cases --
// find the middle and recur on each half
n = nc/2;
for(s=sa; s!=C; s=s->slink) {
n--;
if(n == 0)
break;
}
n = nc/2;
sb = s->slink;
s->slink = C;
p1 = gbranch(AJMP, T); // goto midcmp
p2 = pc; // low half of switch
swconst(sa, n, n1, tmp);
p3 = gbranch(AJMP, T); // goto end
patch(p1, pc);
setlineno(s->scase);
memset(n1, 0, sizeof(*n1));
n1->op = OLE;
n1->left = tmp;
n1->right = s->scase;
walktype(n1, Erv);
bgen(n1, 1, p2);
swconst(sb, nc-n, n1, tmp); // high half of switch
patch(p3, pc);
}
void
swgen(Node *n)
{
Node *c1, *c2;
Node n1, tmp;
Case *s0, *se, *s, *sa;
Prog *p1, *dflt;
int32 lno;
int any, nc;
Iter save1, save2;
// botch - put most of this code in
// walk. gen binary search for
// sequence of constant cases
lno = setlineno(n);
p1 = gbranch(AJMP, T);
s0 = C;
se = C;
// walk thru the body placing breaks
// and labels into the case statements
any = 0;
dflt = P;
c1 = listfirst(&save1, &n->nbody);
while(c1 != N) {
setlineno(c1);
if(c1->op == OEMPTY)
break;
if(c1->op != OCASE) {
if(s0 == C && dflt == P)
yyerror("unreachable statements in a switch");
gen(c1, L);
any = 1;
if(c1->op == OFALL)
any = 0;
c1 = listnext(&save1);
continue;
}
// put in the break between cases
if(any)
patch(gbranch(AJMP, T), breakpc);
any = 1;
// loop over case expressions
c2 = listfirst(&save2, &c1->left);
if(c2 == N)
dflt = pc;
while(c2 != N) {
s = mal(sizeof(*s));
if(s0 == C)
s0 = s;
else
se->slink = s;
se = s;
s->scase = c2; // case expression
s->sprog = pc; // where to go
c2 = listnext(&save2);
}
c1 = listnext(&save1);
}
lineno = lno;
if(any)
patch(gbranch(AJMP, T), breakpc);
patch(p1, pc);
if(n->ntest != N)
if(n->ntest->ninit != N)
gen(n->ntest->ninit, L);
tempname(&tmp, n->ntest->type);
cgen(n->ntest, &tmp);
sa = C; // base of constant cases
nc = 0;
for(s=s0; s!=C; s=s->slink) {
switch(whatis(s->scase)) {
case Wlitfloat:
case Wlitint:
case Wlitstr:
// case Wlitbool:
// case Wlitnil:
nc++;
if(sa == C)
sa = s;
se = s;
continue;
}
if(sa != C) {
se->slink = C;
sa = csort(sa, casecmp);
swconst(sa, nc, &n1, &tmp);
nc = 0;
sa = C;
}
setlineno(s->scase);
memset(&n1, 0, sizeof(n1));
n1.op = OEQ;
n1.left = &tmp;
n1.right = s->scase;
walktype(&n1, Erv);
bgen(&n1, 1, s->sprog);
}
if(sa != C) {
se->slink = C;
sa = csort(sa, casecmp);
swconst(sa, nc, &n1, &tmp);
}
if(dflt != P) {
patch(gbranch(AJMP, T), dflt);
goto ret;
}
patch(gbranch(AJMP, T), breakpc);
ret:
lineno = lno;
}
void
inarggen(void)
{
fatal("inarggen");
}
void
genpanic(void)
{
Node n1, n2;
Prog *p;
nodconst(&n1, types[TINT64], 0xf0);
nodreg(&n2, types[TINT64], D_AX);
gins(AMOVL, &n1, &n2);
p = pc;
gins(AMOVQ, &n2, N);
p->to.type = D_INDIR+D_AX;
}
/*
* compute total size of f's in/out arguments.
*/
int
argsize(Type *t)
{
Iter save;
Type *fp;
int w, x;
w = 0;
fp = structfirst(&save, getoutarg(t));
while(fp != T) {
x = fp->width + fp->type->width;
if(x > w)
w = x;
fp = structnext(&save);
}
fp = funcfirst(&save, t);
while(fp != T) {
x = fp->width + fp->type->width;
if(x > w)
w = x;
fp = funcnext(&save);
}
w = (w+7) & ~7;
return w;
}
/*
* generate:
* call f
* if proc, generate:
* push f
* push argsize
* call newproc
* pop
* pop
*/
void
ginscall(Node *f, int proc)
{
Node reg, con;
if(proc) {
nodreg(®, types[TINT64], D_AX);
if(f->op != OREGISTER) {
gins(ALEAQ, f, ®);
gins(APUSHQ, ®, N);
} else
gins(APUSHQ, f, N);
nodconst(&con, types[TINT32], argsize(f->type));
gins(APUSHQ, &con, N);
gins(ACALL, N, newproc);
gins(APOPQ, N, ®);
gins(APOPQ, N, ®);
return;
}
gins(ACALL, N, f);
}
/*
* n is call to interface method.
* generate res = n.
*/
void
cgen_callinter(Node *n, Node *res, int proc)
{
Node *i, *f;
Node tmpi, nodo, nodr, nodsp;
i = n->left;
if(i->op != ODOTINTER)
fatal("cgen_callinter: not ODOTINTER %O", i->op);
f = i->right; // field
if(f->op != ONAME)
fatal("cgen_callinter: not ONAME %O", f->op);
i = i->left; // interface
if(!i->addable) {
tempname(&tmpi, i->type);
cgen(i, &tmpi);
i = &tmpi;
}
gen(n->right, L); // args
regalloc(&nodr, types[tptr], res);
regalloc(&nodo, types[tptr], &nodr);
nodo.op = OINDREG;
agen(i, &nodr); // REG = &inter
nodindreg(&nodsp, types[tptr], D_SP);
nodo.xoffset += widthptr;
cgen(&nodo, &nodsp); // 0(SP) = 8(REG) -- i.s
nodo.xoffset -= widthptr;
cgen(&nodo, &nodr); // REG = 0(REG) -- i.m
nodo.xoffset = n->left->xoffset + 4*widthptr;
cgen(&nodo, &nodr); // REG = 32+offset(REG) -- i.m->fun[f]
// BOTCH nodr.type = fntype;
ginscall(&nodr, proc);
regfree(&nodr);
regfree(&nodo);
setmaxarg(n->left->type);
}
/*
* generate call to non-interface method
*/
void
cgen_callmeth(Node *n, int proc)
{
Node *l;
// generate a rewrite for method call
// (p.f)(...) goes to (f)(p,...)
l = n->left;
if(l->op != ODOTMETH)
fatal("cgen_callmeth: not dotmethod: %N");
n->op = OCALL;
n->left = n->left->right;
n->left->type = l->type;
if(n->left->op == ONAME)
n->left->class = PEXTERN;
cgen_call(n, proc);
}
/*
* generate function call;
* if proc, run call in new proc.
*/
void
cgen_call(Node *n, int proc)
{
Type *t;
Node nod, afun;
if(n == N)
return;
if(n->left->ullman >= UINF) {
// if name involves a fn call
// precompute the address of the fn
tempname(&afun, types[tptr]);
if(isptr[n->left->type->etype])
cgen(n->left, &afun);
else
agen(n->left, &afun);
}
gen(n->right, L); // assign the args
t = n->left->type;
if(isptr[t->etype])
t = t->type;
setmaxarg(t);
// call tempname pointer
if(n->left->ullman >= UINF) {
regalloc(&nod, types[tptr], N);
cgen_as(&nod, &afun);
nod.type = t;
ginscall(&nod, proc);
regfree(&nod);
goto ret;
}
// call pointer
if(isptr[n->left->type->etype]) {
regalloc(&nod, types[tptr], N);
cgen_as(&nod, n->left);
nod.type = t;
ginscall(&nod, proc);
regfree(&nod);
goto ret;
}
// call direct
n->left->method = 1;
ginscall(n->left, proc);
ret:
;
}
/*
* generate code to start new proc running call n.
*/
void
cgen_proc(Node *n)
{
switch(n->left->op) {
default:
fatal("cgen_proc: unknown call %O", n->left->op);
case OCALLMETH:
cgen_callmeth(n->left, 1);
break;
case OCALLINTER:
cgen_callinter(n->left, N, 1);
break;
case OCALL:
cgen_call(n->left, 1);
break;
}
}
/*
* call to n has already been generated.
* generate:
* res = return value from call.
*/
void
cgen_callret(Node *n, Node *res)
{
Node nod;
Type *fp, *t;
Iter flist;
t = n->left->type;
if(t->etype == TPTR32 || t->etype == TPTR64)
t = t->type;
fp = structfirst(&flist, getoutarg(t));
if(fp == T)
fatal("cgen_callret: nil");
memset(&nod, 0, sizeof(nod));
nod.op = OINDREG;
nod.val.u.reg = D_SP;
nod.addable = 1;
nod.xoffset = fp->width;
nod.type = fp->type;
cgen_as(res, &nod);
}
/*
* call to n has already been generated.
* generate:
* res = &return value from call.
*/
void
cgen_aret(Node *n, Node *res)
{
Node nod1, nod2;
Type *fp, *t;
Iter flist;
t = n->left->type;
if(isptr[t->etype])
t = t->type;
fp = structfirst(&flist, getoutarg(t));
if(fp == T)
fatal("cgen_aret: nil");
memset(&nod1, 0, sizeof(nod1));
nod1.op = OINDREG;
nod1.val.u.reg = D_SP;
nod1.addable = 1;
nod1.xoffset = fp->width;
nod1.type = fp->type;
if(res->op != OREGISTER) {
regalloc(&nod2, types[tptr], res);
gins(ALEAQ, &nod1, &nod2);
gins(AMOVQ, &nod2, res);
regfree(&nod2);
} else
gins(ALEAQ, &nod1, res);
}
/*
* generate return.
* n->left is assignments to return values.
*/
void
cgen_ret(Node *n)
{
gen(n->left, L); // copy out args
gins(ARET, N, N);
}
/*
* generate += *= etc.
*/
void
cgen_asop(Node *n)
{
Node n1, n2, n3, n4;
Node *nl, *nr;
Prog *p1;
Addr addr;
nl = n->left;
nr = n->right;
if(nr->ullman >= UINF && nl->ullman >= UINF) {
tempname(&n1, nr->type);
cgen(nr, &n1);
n2 = *n;
n2.right = &n1;
cgen_asop(&n2);
goto ret;
}
if(!isint[nl->type->etype])
goto hard;
if(!isint[nr->type->etype])
goto hard;
switch(n->etype) {
case OADD:
if(smallintconst(nr))
if(mpgetfix(nr->val.u.xval) == 1) {
if(nl->addable) {
gins(optoas(OINC, nl->type), N, nl);
goto ret;
}
if(sudoaddable(nl, &addr)) {
p1 = gins(optoas(OINC, nl->type), N, N);
p1->to = addr;
sudoclean();
goto ret;
}
}
break;
case OSUB:
if(smallintconst(nr))