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go/src/cmd/gc/pgen.c

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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 <u.h>
#include <libc.h>
#include "gg.h"
#include "opt.h"
static void allocauto(Prog* p);
static void pointermap(Node* fn);
void
compile(Node *fn)
{
Plist *pl;
Node nod1, *n;
Prog *plocals, *ptxt, *p, *p1;
int32 lno;
Type *t;
Iter save;
vlong oldstksize;
NodeList *l;
if(newproc == N) {
newproc = sysfunc("newproc");
deferproc = sysfunc("deferproc");
deferreturn = sysfunc("deferreturn");
panicindex = sysfunc("panicindex");
panicslice = sysfunc("panicslice");
throwreturn = sysfunc("throwreturn");
}
lno = setlineno(fn);
if(fn->nbody == nil) {
if(pure_go || memcmp(fn->nname->sym->name, "init·", 6) == 0)
yyerror("missing function body", fn);
goto ret;
}
saveerrors();
// set up domain for labels
clearlabels();
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);
}
}
order(curfn);
if(nerrors != 0)
goto ret;
hasdefer = 0;
walk(curfn);
if(nerrors != 0)
goto ret;
if(flag_race)
racewalk(curfn);
if(nerrors != 0)
goto ret;
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);
if(fn->dupok)
ptxt->TEXTFLAG = DUPOK;
afunclit(&ptxt->from, curfn->nname);
ginit();
plocals = gins(ALOCALS, N, N);
for(t=curfn->paramfld; t; t=t->down)
gtrack(tracksym(t->type));
for(l=fn->dcl; l; l=l->next) {
n = l->n;
if(n->op != ONAME) // might be OTYPE or OLITERAL
continue;
switch(n->class) {
case PAUTO:
case PPARAM:
case PPARAMOUT:
nodconst(&nod1, types[TUINTPTR], l->n->type->width);
p = gins(ATYPE, l->n, &nod1);
p->from.gotype = ngotype(l->n);
break;
}
}
pointermap(fn);
genlist(curfn->enter);
retpc = nil;
if(hasdefer || curfn->exit) {
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;
allocauto(ptxt);
plocals->to.type = D_CONST;
plocals->to.offset = stksize;
if(0)
print("allocauto: %lld to %lld\n", oldstksize, (vlong)stksize);
setlineno(curfn);
if((int64)stksize+maxarg > (1ULL<<31))
yyerror("stack frame too large (>2GB)");
defframe(ptxt);
if(0)
frame(0);
ret:
lineno = lno;
}
static void
walktype1(Type *t, vlong *xoffset, Bvec *bv)
{
vlong fieldoffset, i, o;
Type *t1;
if(t->align > 0 && (*xoffset % t->align) != 0)
fatal("walktype1: invalid initial alignment, %T", t);
switch(t->etype) {
case TINT8:
case TUINT8:
case TINT16:
case TUINT16:
case TINT32:
case TUINT32:
case TINT64:
case TUINT64:
case TINT:
case TUINT:
case TUINTPTR:
case TBOOL:
case TFLOAT32:
case TFLOAT64:
case TCOMPLEX64:
case TCOMPLEX128:
*xoffset += t->width;
break;
case TPTR32:
case TPTR64:
case TUNSAFEPTR:
case TFUNC:
case TCHAN:
case TMAP:
if(*xoffset % widthptr != 0)
fatal("walktype1: invalid alignment, %T", t);
bvset(bv, *xoffset / widthptr);
*xoffset += t->width;
break;
case TSTRING:
// struct { byte *str; intgo len; }
if(*xoffset % widthptr != 0)
fatal("walktype1: invalid alignment, %T", t);
bvset(bv, *xoffset / widthptr);
*xoffset += t->width;
break;
case TINTER:
// struct { Itab* tab; union { void* ptr, uintptr val } data; }
// or, when isnilinter(t)==true:
// struct { Type* type; union { void* ptr, uintptr val } data; }
if(*xoffset % widthptr != 0)
fatal("walktype1: invalid alignment, %T", t);
bvset(bv, *xoffset / widthptr);
bvset(bv, (*xoffset + widthptr) / widthptr);
*xoffset += t->width;
break;
case TARRAY:
// The value of t->bound is -1 for slices types and >0 for
// for fixed array types. All other values are invalid.
if(t->bound < -1)
fatal("walktype1: invalid bound, %T", t);
if(isslice(t)) {
// struct { byte* array; uintgo len; uintgo cap; }
if(*xoffset % widthptr != 0)
fatal("walktype1: invalid TARRAY alignment, %T", t);
bvset(bv, *xoffset / widthptr);
*xoffset += t->width;
} else if(!haspointers(t->type))
*xoffset += t->width;
else
for(i = 0; i < t->bound; ++i)
walktype1(t->type, xoffset, bv);
break;
case TSTRUCT:
o = 0;
for(t1 = t->type; t1 != T; t1 = t1->down) {
fieldoffset = t1->width;
*xoffset += fieldoffset - o;
walktype1(t1->type, xoffset, bv);
o = fieldoffset + t1->type->width;
}
*xoffset += t->width - o;
break;
default:
fatal("walktype1: unexpected type, %T", t);
}
}
static void
walktype(Type *type, Bvec *bv)
{
vlong xoffset;
// Start the walk at offset 0. The correct offset will be
// filled in by the first type encountered during the walk.
xoffset = 0;
walktype1(type, &xoffset, bv);
}
// Compute a bit vector to describes the pointer containing locations
// in the argument list.
static void
pointermap(Node *fn)
{
Type *thistype, *inargtype, *outargtype;
Bvec *bv;
Prog *prog;
int32 i;
thistype = getthisx(fn->type);
inargtype = getinargx(fn->type);
outargtype = getoutargx(fn->type);
bv = bvalloc(fn->type->argwid / widthptr);
if(thistype != nil)
walktype(thistype, bv);
if(inargtype != nil)
walktype(inargtype, bv);
if(outargtype != nil)
walktype(outargtype, bv);
prog = gins(ANPTRS, N, N);
prog->to.type = D_CONST;
prog->to.offset = bv->n;
for(i = 0; i < bv->n; i += 32) {
prog = gins(APTRS, N, N);
prog->from.type = D_CONST;
prog->from.offset = i / 32;
prog->to.type = D_CONST;
prog->to.offset = bv->b[i / 32];
}
free(bv);
}
// 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) {
if (a->xoffset < b->xoffset)
return -1;
if (a->xoffset > b->xoffset)
return 1;
return 0;
}
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
allocauto(Prog* ptxt)
{
NodeList *ll;
Node* n;
vlong w;
if(curfn->dcl == nil)
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) {
// No locals used at all
curfn->dcl = nil;
stksize = 0;
fixautoused(ptxt);
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;
dowidth(n->type);
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);
if(stksize >= (1ULL<<31)) {
setlineno(curfn);
yyerror("stack frame too large (>2GB)");
}
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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