592 lines
10 KiB
C
592 lines
10 KiB
C
#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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hasdoubled = 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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if(typecmplx[thisfn->link->etype]) {
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if(nodret == nil) {
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nodret = new(ONAME, Z, Z);
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nodret->sym = slookup(".ret");
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nodret->class = CPARAM;
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nodret->type = types[TIND];
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nodret->etype = TIND;
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nodret = new(OIND, nodret, Z);
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}
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n1 = nodret->left;
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if(n1->type == T || n1->type->link != thisfn->link) {
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n1->type = typ(TIND, thisfn->link);
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n1->etype = n1->type->etype;
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nodret = new(OIND, n1, Z);
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complex(nodret);
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}
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}
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/*
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* isolate first argument
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*/
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if(REGARG >= 0) {
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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 = znode;
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nod1.op = ONAME;
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nod1.sym = firstarg;
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nod1.type = firstargtype;
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nod1.class = CPARAM;
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nod1.xoffset = align(0, firstargtype, Aarg1);
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nod1.etype = firstargtype->etype;
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xcom(&nod1);
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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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if(debug['B'])
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warn(Z, "no return at end of function: %s", n1->sym->name);
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else
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diag(Z, "no return at end of function: %s", n1->sym->name);
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}
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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' || thechar=='9' || hasdoubled) /* [sic] */
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maxargsafe = round(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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Node*
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uncomma(Node *n)
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{
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while(n != Z && n->op == OCOMMA) {
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cgen(n->left, Z);
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n = n->right;
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}
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return n;
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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, rn;
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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 OCOMMA:
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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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case OCOMMA:
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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 = uncomma(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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nod = znode;
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nod.op = OAS;
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nod.left = nodret;
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nod.right = l;
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nod.type = n->type;
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nod.complex = l->complex;
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cgen(&nod, 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(newvlongcode && !typefd[n->type->etype]){
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regret(&rn, n);
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regfree(&rn);
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nod = znode;
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nod.op = OAS;
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nod.left = &rn;
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nod.right = l;
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nod.type = n->type;
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nod.complex = l->complex;
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cgen(&nod, Z);
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noretval(2);
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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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casf();
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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 || !typeswitch[l->type->etype]) {
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diag(n, "case expression must be integer constant");
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goto rloop;
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}
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casf();
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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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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(!typeswitch[l->type->etype]) {
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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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casf();
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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;
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canreach = oldreach;
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}
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}
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else {
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sp = p;
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canreach = 1;
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if(n->right->left != Z)
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gen(n->right->left);
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oldreach = canreach;
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canreach = 1;
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if(n->right->right != Z) {
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gbranch(OGOTO);
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patch(sp, pc);
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sp = p;
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gen(n->right->right);
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}
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patch(sp, pc);
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canreach = canreach || oldreach;
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if(canreach == 0)
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warnreach = !suppress;
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}
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break;
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case OSET:
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case OUSED:
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usedset(n->left, o);
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break;
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}
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}
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void
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usedset(Node *n, int o)
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{
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if(n->op == OLIST) {
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usedset(n->left, o);
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usedset(n->right, o);
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return;
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}
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complex(n);
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switch(n->op) {
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case OADDR: /* volatile */
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gins(ANOP, n, Z);
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break;
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case ONAME:
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if(o == OSET)
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gins(ANOP, Z, n);
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else
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gins(ANOP, n, Z);
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break;
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}
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}
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int
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bcomplex(Node *n, Node *c)
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{
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Node *b, nod;
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complex(n);
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if(n->type != T)
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if(tcompat(n, T, n->type, tnot))
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n->type = T;
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if(n->type == T) {
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gbranch(OGOTO);
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return 0;
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}
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if(c != Z && n->op == OCONST && deadheads(c))
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return 1;
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/* this is not quite right yet, so ignore it for now */
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if(0 && newvlongcode && typev[n->type->etype] && machcap(Z)) {
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b = &nod;
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b->op = ONE;
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b->left = n;
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b->right = new(0, Z, Z);
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*b->right = *nodconst(0);
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b->right->type = n->type;
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b->type = types[TLONG];
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cgen(b, Z);
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return 0;
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}
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bool64(n);
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boolgen(n, 1, Z);
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return 0;
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}
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