Type assign(Type xty, Tree e) {
Type yty = unqual(e->type);
xty = unqual(xty);
if (isenum(xty))
xty = xty->type;
if (xty->size == 0 || yty->size == 0)
return NULL;
if ( isarith(xty) && isarith(yty)
|| isstruct(xty) && xty == yty)
return xty;
if (isptr(xty) && isnullptr(e))
return xty;
if ((isvoidptr(xty) && isptr(yty)
|| isptr(xty) && isvoidptr(yty))
&& ( (isconst(xty->type) || !isconst(yty->type))
&& (isvolatile(xty->type) || !isvolatile(yty->type))))
return xty;
if ((isptr(xty) && isptr(yty)
&& eqtype(unqual(xty->type), unqual(yty->type), 1))
&& ( (isconst(xty->type) || !isconst(yty->type))
&& (isvolatile(xty->type) || !isvolatile(yty->type))))
return xty;
if (isptr(xty) && isptr(yty)
&& ( (isconst(xty->type) || !isconst(yty->type))
&& (isvolatile(xty->type) || !isvolatile(yty->type)))) {
Type lty = unqual(xty->type), rty = unqual(yty->type);
if (isenum(lty) && rty == inttype
|| isenum(rty) && lty == inttype) {
if (Aflag >= 1)
warning("assignment between `%t' and `%t' is compiler-dependent\n",
xty, yty);
return xty;
}
}
return NULL;
}
Tree unary(void) {
Tree p;
switch (t) {
case '*': t = gettok(); p = unary(); p = pointer(p);
if (isptr(p->type)
&& (isfunc(p->type->type) || isarray(p->type->type)))
p = retype(p, p->type->type);
else {
if (YYnull)
p = nullcheck(p);
p = rvalue(p);
} break;
case '&': t = gettok(); p = unary(); if (isarray(p->type) || isfunc(p->type))
p = retype(p, ptr(p->type));
else
p = lvalue(p);
if (isaddrop(p->op) && p->u.sym->sclass == REGISTER)
error("invalid operand of unary &; `%s' is declared register\n", p->u.sym->name);
else if (isaddrop(p->op))
p->u.sym->addressed = 1;
break;
case '+': t = gettok(); p = unary(); p = pointer(p);
if (isarith(p->type))
p = cast(p, promote(p->type));
else
typeerror(ADD, p, NULL); break;
case '-': t = gettok(); p = unary(); p = pointer(p);
if (isarith(p->type)) {
Type ty = promote(p->type);
p = cast(p, ty);
if (isunsigned(ty)) {
warning("unsigned operand of unary -\n");
p = simplify(ADD, ty, simplify(BCOM, ty, p, NULL), cnsttree(ty, 1UL));
} else
p = simplify(NEG, ty, p, NULL);
} else
typeerror(SUB, p, NULL); break;
case '~': t = gettok(); p = unary(); p = pointer(p);
if (isint(p->type)) {
Type ty = promote(p->type);
p = simplify(BCOM, ty, cast(p, ty), NULL);
} else
typeerror(BCOM, p, NULL); break;
case '!': t = gettok(); p = unary(); p = pointer(p);
if (isscalar(p->type))
p = simplify(NOT, inttype, cond(p), NULL);
else
typeerror(NOT, p, NULL); break;
case INCR: t = gettok(); p = unary(); p = incr(INCR, pointer(p), consttree(1, inttype)); break;
case DECR: t = gettok(); p = unary(); p = incr(DECR, pointer(p), consttree(1, inttype)); break;
case TYPECODE: case SIZEOF: { int op = t;
Type ty;
p = NULL;
t = gettok();
if (t == '(') {
t = gettok();
if (istypename(t, tsym)) {
ty = typename();
expect(')');
} else {
p = postfix(expr(')'));
ty = p->type;
}
} else {
