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551 lines
10 KiB
C
551 lines
10 KiB
C
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// Inferno utils/6c/sgen.c
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// http://code.google.com/p/inferno-os/source/browse/utils/6c/sgen.c
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//
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// Copyright © 1994-1999 Lucent Technologies Inc. All rights reserved.
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// Portions Copyright © 1995-1997 C H Forsyth (forsyth@terzarima.net)
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// Portions Copyright © 1997-1999 Vita Nuova Limited
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// Portions Copyright © 2000-2007 Vita Nuova Holdings Limited (www.vitanuova.com)
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// Portions Copyright © 2004,2006 Bruce Ellis
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// Portions Copyright © 2005-2007 C H Forsyth (forsyth@terzarima.net)
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// Revisions Copyright © 2000-2007 Lucent Technologies Inc. and others
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// Portions Copyright © 2009 The Go Authors. All rights reserved.
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//
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// Permission is hereby granted, free of charge, to any person obtaining a copy
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// of this software and associated documentation files (the "Software"), to deal
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// in the Software without restriction, including without limitation the rights
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// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
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// copies of the Software, and to permit persons to whom the Software is
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// furnished to do so, subject to the following conditions:
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//
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// The above copyright notice and this permission notice shall be included in
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// all copies or substantial portions of the Software.
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//
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// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
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// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
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// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
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// THE SOFTWARE.
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#include "gc.h"
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void
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codgen(Node *n, Node *nn)
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{
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Prog *sp;
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Node *n1, nod, nod1;
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cursafe = 0;
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curarg = 0;
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maxargsafe = 0;
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/*
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* isolate name
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*/
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for(n1 = nn;; n1 = n1->left) {
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if(n1 == Z) {
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diag(nn, "cant find function name");
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return;
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}
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if(n1->op == ONAME)
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break;
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}
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nearln = nn->lineno;
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gpseudo(ATEXT, n1->sym, nodconst(stkoff));
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sp = p;
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/*
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* isolate first argument
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*/
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if(REGARG) {
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if(typecmplx[thisfn->link->etype]) {
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nod1 = *nodret->left;
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nodreg(&nod, &nod1, REGARG);
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gmove(&nod, &nod1);
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} else
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if(firstarg && typeword[firstargtype->etype]) {
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nod1 = *nodret->left;
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nod1.sym = firstarg;
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nod1.type = firstargtype;
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nod1.xoffset = align(0, firstargtype, Aarg1);
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nod1.etype = firstargtype->etype;
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nodreg(&nod, &nod1, REGARG);
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gmove(&nod, &nod1);
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}
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}
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canreach = 1;
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warnreach = 1;
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gen(n);
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if(canreach && thisfn->link->etype != TVOID)
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warn(Z, "no return at end of function: %s", n1->sym->name);
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noretval(3);
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gbranch(ORETURN);
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if(!debug['N'] || debug['R'] || debug['P'])
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regopt(sp);
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if(thechar=='6' || thechar=='7') /* [sic] */
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maxargsafe = xround(maxargsafe, 8);
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sp->to.offset += maxargsafe;
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}
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void
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supgen(Node *n)
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{
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int owarn;
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long spc;
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Prog *sp;
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if(n == Z)
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return;
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suppress++;
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owarn = warnreach;
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warnreach = 0;
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spc = pc;
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sp = lastp;
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gen(n);
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lastp = sp;
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pc = spc;
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sp->link = nil;
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suppress--;
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warnreach = owarn;
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}
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void
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gen(Node *n)
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{
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Node *l, nod;
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Prog *sp, *spc, *spb;
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Case *cn;
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long sbc, scc;
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int snbreak, sncontin;
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int f, o, oldreach;
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loop:
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if(n == Z)
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return;
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nearln = n->lineno;
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o = n->op;
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if(debug['G'])
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if(o != OLIST)
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print("%L %O\n", nearln, o);
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if(!canreach) {
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switch(o) {
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case OLABEL:
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case OCASE:
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case OLIST:
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case OBREAK:
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case OFOR:
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case OWHILE:
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case ODWHILE:
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/* all handled specially - see switch body below */
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break;
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default:
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if(warnreach) {
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warn(n, "unreachable code %O", o);
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warnreach = 0;
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}
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}
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}
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switch(o) {
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default:
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complex(n);
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cgen(n, Z);
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break;
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case OLIST:
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gen(n->left);
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rloop:
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n = n->right;
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goto loop;
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case ORETURN:
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canreach = 0;
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warnreach = !suppress;
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complex(n);
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if(n->type == T)
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break;
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l = n->left;
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if(l == Z) {
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noretval(3);
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gbranch(ORETURN);
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break;
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}
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if(typecmplx[n->type->etype]) {
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sugen(l, nodret, n->type->width);
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noretval(3);
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gbranch(ORETURN);
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break;
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}
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regret(&nod, n);
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cgen(l, &nod);
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regfree(&nod);
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if(typefd[n->type->etype])
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noretval(1);
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else
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noretval(2);
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gbranch(ORETURN);
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break;
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case OLABEL:
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canreach = 1;
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l = n->left;
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if(l) {
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l->pc = pc;
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if(l->label)
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patch(l->label, pc);
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}
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gbranch(OGOTO); /* prevent self reference in reg */
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patch(p, pc);
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goto rloop;
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case OGOTO:
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canreach = 0;
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warnreach = !suppress;
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n = n->left;
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if(n == Z)
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return;
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if(n->complex == 0) {
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diag(Z, "label undefined: %s", n->sym->name);
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return;
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}
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if(suppress)
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return;
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gbranch(OGOTO);
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if(n->pc) {
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patch(p, n->pc);
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return;
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}
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if(n->label)
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patch(n->label, pc-1);
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n->label = p;
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return;
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case OCASE:
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canreach = 1;
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l = n->left;
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if(cases == C)
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diag(n, "case/default outside a switch");
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if(l == Z) {
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cas();
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cases->val = 0;
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cases->def = 1;
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cases->label = pc;
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cases->isv = 0;
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goto rloop;
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}
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complex(l);
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if(l->type == T)
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goto rloop;
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if(l->op == OCONST)
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if(typeword[l->type->etype] && l->type->etype != TIND) {
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cas();
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cases->val = l->vconst;
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cases->def = 0;
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cases->label = pc;
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cases->isv = typev[l->type->etype];
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goto rloop;
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}
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diag(n, "case expression must be integer constant");
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goto rloop;
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case OSWITCH:
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l = n->left;
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complex(l);
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if(l->type == T)
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break;
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if(!typeword[l->type->etype] || l->type->etype == TIND) {
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diag(n, "switch expression must be integer");
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break;
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}
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gbranch(OGOTO); /* entry */
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sp = p;
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cn = cases;
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cases = C;
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cas();
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sbc = breakpc;
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breakpc = pc;
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snbreak = nbreak;
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nbreak = 0;
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gbranch(OGOTO);
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spb = p;
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gen(n->right); /* body */
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if(canreach){
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gbranch(OGOTO);
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patch(p, breakpc);
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nbreak++;
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}
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patch(sp, pc);
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regalloc(&nod, l, Z);
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/* always signed */
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if(typev[l->type->etype])
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nod.type = types[TVLONG];
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else
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nod.type = types[TLONG];
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cgen(l, &nod);
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doswit(&nod);
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regfree(&nod);
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patch(spb, pc);
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cases = cn;
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breakpc = sbc;
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canreach = nbreak!=0;
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if(canreach == 0)
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warnreach = !suppress;
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nbreak = snbreak;
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break;
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case OWHILE:
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case ODWHILE:
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l = n->left;
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gbranch(OGOTO); /* entry */
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sp = p;
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scc = continpc;
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continpc = pc;
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gbranch(OGOTO);
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spc = p;
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sbc = breakpc;
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breakpc = pc;
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snbreak = nbreak;
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nbreak = 0;
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gbranch(OGOTO);
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spb = p;
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patch(spc, pc);
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if(n->op == OWHILE)
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patch(sp, pc);
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bcomplex(l, Z); /* test */
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patch(p, breakpc);
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if(l->op != OCONST || vconst(l) == 0)
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nbreak++;
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if(n->op == ODWHILE)
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patch(sp, pc);
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gen(n->right); /* body */
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gbranch(OGOTO);
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patch(p, continpc);
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patch(spb, pc);
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continpc = scc;
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breakpc = sbc;
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canreach = nbreak!=0;
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if(canreach == 0)
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warnreach = !suppress;
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nbreak = snbreak;
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break;
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case OFOR:
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l = n->left;
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if(!canreach && l->right->left && warnreach) {
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warn(n, "unreachable code FOR");
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warnreach = 0;
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}
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gen(l->right->left); /* init */
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gbranch(OGOTO); /* entry */
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sp = p;
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/*
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* if there are no incoming labels in the
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* body and the top's not reachable, warn
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*/
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if(!canreach && warnreach && deadheads(n)) {
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warn(n, "unreachable code %O", o);
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warnreach = 0;
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}
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scc = continpc;
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continpc = pc;
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gbranch(OGOTO);
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spc = p;
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sbc = breakpc;
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breakpc = pc;
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snbreak = nbreak;
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nbreak = 0;
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sncontin = ncontin;
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ncontin = 0;
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gbranch(OGOTO);
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spb = p;
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patch(spc, pc);
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gen(l->right->right); /* inc */
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patch(sp, pc);
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if(l->left != Z) { /* test */
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bcomplex(l->left, Z);
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patch(p, breakpc);
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if(l->left->op != OCONST || vconst(l->left) == 0)
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nbreak++;
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}
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canreach = 1;
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gen(n->right); /* body */
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if(canreach){
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gbranch(OGOTO);
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patch(p, continpc);
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ncontin++;
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}
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if(!ncontin && l->right->right && warnreach) {
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warn(l->right->right, "unreachable FOR inc");
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warnreach = 0;
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}
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patch(spb, pc);
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continpc = scc;
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breakpc = sbc;
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canreach = nbreak!=0;
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if(canreach == 0)
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warnreach = !suppress;
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nbreak = snbreak;
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ncontin = sncontin;
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break;
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case OCONTINUE:
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if(continpc < 0) {
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diag(n, "continue not in a loop");
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break;
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}
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gbranch(OGOTO);
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patch(p, continpc);
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ncontin++;
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canreach = 0;
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warnreach = !suppress;
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break;
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case OBREAK:
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if(breakpc < 0) {
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diag(n, "break not in a loop");
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break;
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}
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/*
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* Don't complain about unreachable break statements.
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* There are breaks hidden in yacc's output and some people
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* write return; break; in their switch statements out of habit.
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* However, don't confuse the analysis by inserting an
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* unreachable reference to breakpc either.
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*/
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if(!canreach)
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break;
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gbranch(OGOTO);
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patch(p, breakpc);
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nbreak++;
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canreach = 0;
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warnreach = !suppress;
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break;
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case OIF:
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l = n->left;
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if(bcomplex(l, n->right)) {
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if(typefd[l->type->etype])
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f = !l->fconst;
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else
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f = !l->vconst;
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if(debug['c'])
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print("%L const if %s\n", nearln, f ? "false" : "true");
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if(f) {
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canreach = 1;
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supgen(n->right->left);
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oldreach = canreach;
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canreach = 1;
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gen(n->right->right);
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/*
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* treat constant ifs as regular ifs for
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* reachability warnings.
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*/
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if(!canreach && oldreach && debug['w'] < 2)
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warnreach = 0;
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}
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else {
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canreach = 1;
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gen(n->right->left);
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oldreach = canreach;
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canreach = 1;
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supgen(n->right->right);
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/*
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|
* treat constant ifs as regular ifs for
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* reachability warnings.
|
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*/
|
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if(!oldreach && canreach && debug['w'] < 2)
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|
warnreach = 0;
|
||
|
canreach = oldreach;
|
||
|
}
|
||
|
}
|
||
|
else {
|
||
|
sp = p;
|
||
|
canreach = 1;
|
||
|
if(n->right->left != Z)
|
||
|
gen(n->right->left);
|
||
|
oldreach = canreach;
|
||
|
canreach = 1;
|
||
|
if(n->right->right != Z) {
|
||
|
gbranch(OGOTO);
|
||
|
patch(sp, pc);
|
||
|
sp = p;
|
||
|
gen(n->right->right);
|
||
|
}
|
||
|
patch(sp, pc);
|
||
|
canreach = canreach || oldreach;
|
||
|
if(canreach == 0)
|
||
|
warnreach = !suppress;
|
||
|
}
|
||
|
break;
|
||
|
|
||
|
case OSET:
|
||
|
case OUSED:
|
||
|
usedset(n->left, o);
|
||
|
break;
|
||
|
}
|
||
|
}
|
||
|
|
||
|
void
|
||
|
usedset(Node *n, int o)
|
||
|
{
|
||
|
if(n->op == OLIST) {
|
||
|
usedset(n->left, o);
|
||
|
usedset(n->right, o);
|
||
|
return;
|
||
|
}
|
||
|
complex(n);
|
||
|
switch(n->op) {
|
||
|
case OADDR: /* volatile */
|
||
|
gins(ANOP, n, Z);
|
||
|
break;
|
||
|
case ONAME:
|
||
|
if(o == OSET)
|
||
|
gins(ANOP, Z, n);
|
||
|
else
|
||
|
gins(ANOP, n, Z);
|
||
|
break;
|
||
|
}
|
||
|
}
|
||
|
|
||
|
int
|
||
|
bcomplex(Node *n, Node *c)
|
||
|
{
|
||
|
|
||
|
complex(n);
|
||
|
if(n->type != T)
|
||
|
if(tcompat(n, T, n->type, tnot))
|
||
|
n->type = T;
|
||
|
if(n->type == T) {
|
||
|
gbranch(OGOTO);
|
||
|
return 0;
|
||
|
}
|
||
|
if(c != Z && n->op == OCONST && deadheads(c))
|
||
|
return 1;
|
||
|
bool64(n);
|
||
|
boolgen(n, 1, Z);
|
||
|
return 0;
|
||
|
}
|