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revised the treatment of "e op= f" expression

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This commit is contained in:
erikb
1986-08-13 10:05:39 +00:00
parent 8217bef1eb
commit a7e97524e4
7 changed files with 106 additions and 92 deletions
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104
lang/cem/cemcom/ch7.c
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@@ -192,9 +192,6 @@ ch7cast(expp, oper, tp)
if ((*expp)->ex_class == String)
string2pointer(expp);
oldtp = (*expp)->ex_type;
if (oldtp == tp)
{} /* life is easy */
else
#ifndef NOBITFIELD
if (oldtp->tp_fund == FIELD) {
field2arith(expp);
@@ -205,6 +202,9 @@ ch7cast(expp, oper, tp)
ch7cast(expp, oper, tp->tp_up);
else
#endif NOBITFIELD
if (oldtp == tp)
{} /* life is easy */
else
if (tp->tp_fund == VOID) /* Easy again */
(*expp)->ex_type = void_type;
else
@@ -311,6 +311,17 @@ ch7asgn(expp, oper, expr)
struct expr *expr;
{
/* The assignment operators.
"f op= e" should be interpreted as
"f = (typeof f)((typeof (f op e))f op (typeof (f op e))e)"
and not as "f = f op (typeof f)e".
Consider, for example, (i == 10) i *= 0.9; (i == 9), where
typeof i == int.
The resulting expression tree becomes:
op=
/ \
/ \
f (typeof (f op e))e
EVAL should however take care of evaluating (typeof (f op e))f
*/
int fund = (*expp)->ex_type->tp_fund;
@@ -320,48 +331,30 @@ ch7asgn(expp, oper, expr)
(*expp)->ex_depth = 99; /* no direct store/load at EVAL() */
/* what is 99 ??? DG */
}
switch (oper) {
case '=':
if (oper == '=') {
ch7cast(&expr, oper, (*expp)->ex_type);
break;
case TIMESAB:
case DIVAB:
case MODAB:
check_arith_type(expp, oper);
any2arith(&expr, oper);
ch7cast(&expr, CAST, (*expp)->ex_type);
break;
case PLUSAB:
case MINAB:
any2arith(&expr, oper);
if (fund == POINTER) {
check_integral_type(&expr, oper);
ch7bin(&expr, '*',
intexpr(
size_of_type(
(*expp)->ex_type->tp_up,
"object"
),
pa_type->tp_fund
)
);
}
else { /* turn e into e' where typeof(e') = typeof (f op e) */
struct expr *extmp = intexpr(0, INT);
/* this is really $#@&*%$# ! */
extmp->ex_lvalue = 1;
extmp->ex_type = (*expp)->ex_type;
ch7bin(&extmp, oper, expr);
/* note that ch7bin creates a tree of the expression
((typeof (f op e))f op (typeof (f op e))e),
where f ~ extmp and e ~ expr;
we have to use (typeof (f op e))e
Ch7bin does not create a tree if both operands
were illegal or constants!
*/
if (extmp->ex_class == Oper) {
expr = extmp->OP_RIGHT;
extmp->OP_RIGHT = NILEXPR;
free_expression(extmp);
}
else {
check_arith_type(expp, oper);
ch7cast(&expr, CAST, (*expp)->ex_type);
}
break;
case LEFTAB:
case RIGHTAB:
check_integral_type(expp, oper);
ch7cast(&expr, oper, int_type);
break;
case ANDAB:
case XORAB:
case ORAB:
check_integral_type(expp, oper);
ch7cast(&expr, oper, (*expp)->ex_type);
break;
else
expr = extmp;
}
#ifndef NOBITFIELD
if (fund == FIELD)
@@ -369,6 +362,7 @@ ch7asgn(expp, oper, expr)
else
#endif NOBITFIELD
*expp = new_oper((*expp)->ex_type, *expp, oper, expr);
(*expp)->OP_TYPE = expr->ex_type; /* for EVAL() */
}
/* Some interesting (?) questions answered.
@@ -393,18 +387,6 @@ is_integral_type(tp)
}
}
check_integral_type(expp, oper)
struct expr **expp;
{
register struct expr *expr = *expp;
if (!is_integral_type(expr->ex_type)) {
expr_error(expr, "%s on non-integral type (%s)",
symbol2str(oper), symbol2str(expr->ex_type->tp_fund));
erroneous2int(expp);
}
}
int
is_arith_type(tp)
struct type *tp;
@@ -426,15 +408,3 @@ is_arith_type(tp)
return 0;
}
}
check_arith_type(expp, oper)
struct expr **expp;
{
register struct expr *expr = *expp;
if (!is_arith_type(expr->ex_type)) {
expr_error(expr, "%s on non-arithmetical type (%s)",
symbol2str(oper), symbol2str(expr->ex_type->tp_fund));
erroneous2int(expp);
}
}