ack/util/grind/value.c
1990-08-31 18:22:53 +00:00

126 lines
2.6 KiB
C

/* $Header$ */
#include <alloc.h>
#include "position.h"
#include "scope.h"
#include "symbol.h"
#include "type.h"
#include "message.h"
int stack_offset; /* for up and down commands */
extern long pointer_size;
extern t_addr *get_EM_regs();
/* Get the value of the symbol indicated by sym.
Return 0 on failure,
1 on success.
On success, 'buf' contains the value, and 'AB' may contain the parameters
of the procedure invocation containing sym.
For both of these, storage is allocated by Malloc; this storage must
be freed by caller (I don't like this any more than you do, but caller
does not know sizes).
*/
int
get_value(sym, buf, AB)
register p_symbol sym;
char **buf, **AB;
{
p_type tp = sym->sy_type;
long size = tp->ty_size;
int retval = 0;
t_addr *EM_regs;
int i;
p_scope sc, symsc;
*buf = 0;
*AB = 0;
switch(sym->sy_class) {
case VAR:
/* exists if child exists; nm_value contains addres */
*buf = Malloc((unsigned) size);
if (get_bytes(size, (t_addr) sym->sy_name.nm_value, *buf)) {
retval = 1;
}
break;
case VARPAR:
case LOCVAR:
/* first find the stack frame in which it resides */
symsc = base_scope(sym->sy_scope);
/* now symsc contains the scope where the storage for sym is
allocated. Now find it on the stack of child.
*/
i = stack_offset;
for (;;) {
sc = 0;
if (! (EM_regs = get_EM_regs(i++))) {
/* no child? */
break;
}
if (! EM_regs[AB_OFF]) {
/* no more frames */
break;
}
sc = base_scope(get_scope_from_addr(EM_regs[PC_OFF]));
if (! sc || sc->sc_start > EM_regs[PC_OFF]) {
sc = 0;
break;
}
if (sc == symsc) break; /* found it */
}
if (! sc) break; /* not found */
if (sym->sy_class == LOCVAR) {
/* Either local variable or value parameter */
*buf = Malloc((unsigned) size);
if (get_bytes(size,
EM_regs[sym->sy_name.nm_value < 0
? LB_OFF
: AB_OFF
] +
(t_addr) sym->sy_name.nm_value,
*buf)) {
retval = 1;
}
break;
}
/* If we get here, we have a var parameter. Get the parameters
of the current procedure invocation.
*/
{
p_type proctype = sc->sc_definedby->sy_type;
size = proctype->ty_nbparams;
if (has_static_link(sc)) size += pointer_size;
*AB = Malloc((unsigned) size);
if (! get_bytes(size, EM_regs[AB_OFF], *AB)) {
break;
}
if ((size = tp->ty_size) == 0) {
size = compute_size(tp, *AB);
}
}
*buf = Malloc((unsigned) size);
if (get_bytes(size,
(t_addr) BUFTOA(*AB+sym->sy_name.nm_value),
*buf)) {
retval = 1;
}
break;
}
if (retval == 0) {
if (*buf) free(*buf);
if (*AB) free(*AB);
*buf = 0;
*AB = 0;
}
return retval;
}