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// Copyright 2011 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.
#include "gg.h"
#include "opt.h"
static void compactframe(Prog* p);
void
compile(Node *fn)
{
Plist *pl;
Node nod1, *n;
Prog *ptxt;
int32 lno;
Type *t;
Iter save;
vlong oldstksize;
if(newproc == N) {
newproc = sysfunc("newproc");
deferproc = sysfunc("deferproc");
deferreturn = sysfunc("deferreturn");
panicindex = sysfunc("panicindex");
panicslice = sysfunc("panicslice");
throwreturn = sysfunc("throwreturn");
}
if(fn->nbody == nil)
return;
saveerrors();
// set up domain for labels
clearlabels();
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) {
n = nod(OAS, t->nname, N);
typecheck(&n, Etop);
curfn->nbody = concat(list1(n), curfn->nbody);
}
t = structnext(&save);
}
}
hasdefer = 0;
walk(curfn);
if(nerrors != 0)
goto ret;
allocparams();
continpc = P;
breakpc = P;
pl = newplist();
pl->name = curfn->nname;
setlineno(curfn);
nodconst(&nod1, types[TINT32], 0);
ptxt = gins(ATEXT, isblank(curfn->nname) ? N : curfn->nname, &nod1);
afunclit(&ptxt->from);
ginit();
genlist(curfn->enter);
retpc = nil;
if(hasdefer || curfn->exit) {
Prog *p1;
p1 = gjmp(nil);
retpc = gjmp(nil);
patch(p1, pc);
}
genlist(curfn->nbody);
gclean();
checklabels();
if(nerrors != 0)
goto ret;
if(curfn->endlineno)
lineno = curfn->endlineno;
if(curfn->type->outtuple != 0)
ginscall(throwreturn, 0);
if(retpc)
patch(retpc, pc);
ginit();
if(hasdefer)
ginscall(deferreturn, 0);
if(curfn->exit)
genlist(curfn->exit);
gclean();
if(nerrors != 0)
goto ret;
pc->as = ARET; // overwrite AEND
pc->lineno = lineno;
if(!debug['N'] || debug['R'] || debug['P']) {
regopt(ptxt);
}
oldstksize = stksize;
compactframe(ptxt);
if(0)
print("compactframe: %ld to %ld\n", oldstksize, stksize);
defframe(ptxt);
if(0)
frame(0);
ret:
lineno = lno;
}
// Sort the list of stack variables. autos after anything else,
// within autos, unused after used, and within used on reverse alignment.
// non-autos sort on offset.
static int
cmpstackvar(Node *a, Node *b)
{
if (a->class != b->class)
return (a->class == PAUTO) ? 1 : -1;
if (a->class != PAUTO)
return a->xoffset - b->xoffset;
if ((a->used == 0) != (b->used == 0))
return b->used - a->used;
return b->type->align - a->type->align;
}
// TODO(lvd) find out where the PAUTO/OLITERAL nodes come from.
static void
compactframe(Prog* ptxt)
{
NodeList *ll;
Node* n;
vlong w;
if (stksize == 0)
return;
// Mark the PAUTO's unused.
for(ll=curfn->dcl; ll != nil; ll=ll->next)
if (ll->n->class == PAUTO)
ll->n->used = 0;
markautoused(ptxt);
listsort(&curfn->dcl, cmpstackvar);
// Unused autos are at the end, chop 'em off.
ll = curfn->dcl;
n = ll->n;
if (n->class == PAUTO && n->op == ONAME && !n->used) {
curfn->dcl = nil;
stksize = 0;
return;
}
for(ll = curfn->dcl; ll->next != nil; ll=ll->next) {
n = ll->next->n;
if (n->class == PAUTO && n->op == ONAME && !n->used) {
ll->next = nil;
curfn->dcl->end = ll;
break;
}
}
// Reassign stack offsets of the locals that are still there.
stksize = 0;
for(ll = curfn->dcl; ll != nil; ll=ll->next) {
n = ll->n;
if (n->class != PAUTO || n->op != ONAME)
continue;
w = n->type->width;
if(w >= MAXWIDTH || w < 0)
fatal("bad width");
stksize += w;
stksize = rnd(stksize, n->type->align);
if(thechar == '5')
stksize = rnd(stksize, widthptr);
n->stkdelta = -stksize - n->xoffset;
}
fixautoused(ptxt);
// The debug information needs accurate offsets on the symbols.
for(ll = curfn->dcl ;ll != nil; ll=ll->next) {
if (ll->n->class != PAUTO || ll->n->op != ONAME)
continue;
ll->n->xoffset += ll->n->stkdelta;
ll->n->stkdelta = 0;
}
}
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