diff options
Diffstat (limited to 'src/cmd/gc/pgen.c')
| -rw-r--r-- | src/cmd/gc/pgen.c | 210 |
1 files changed, 210 insertions, 0 deletions
diff --git a/src/cmd/gc/pgen.c b/src/cmd/gc/pgen.c new file mode 100644 index 000000000..abe8ea892 --- /dev/null +++ b/src/cmd/gc/pgen.c @@ -0,0 +1,210 @@ +// 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; + } +} |