/*
* Use the DWARF expression for the Call-frame-address and determine
* if return address is in LR and if a new frame was allocated.
*/
static int check_return_reg(int ra_regno, Dwarf_Frame *frame)
{
Dwarf_Op ops_mem[2];
Dwarf_Op dummy;
Dwarf_Op *ops = &dummy;
size_t nops;
int result;
result = dwarf_frame_register(frame, ra_regno, ops_mem, &ops, &nops);
if (result < 0) {
pr_debug("dwarf_frame_register() %s\n", dwarf_errmsg(-1));
return -1;
}
/*
* Check if return address is on the stack. If return address
* is in a register (typically R0), it is yet to be saved on
* the stack.
*/
if ((nops != 0 || ops != NULL) &&
!(nops == 1 && ops[0].atom == DW_OP_regx &&
ops[0].number2 == 0 && ops[0].offset == 0))
return 0;
/*
* Return address is in LR. Check if a frame was allocated
* but not-yet used.
*/
result = dwarf_frame_cfa(frame, &ops, &nops);
if (result < 0) {
pr_debug("dwarf_frame_cfa() returns %d, %s\n", result,
dwarf_errmsg(-1));
return -1;
}
/*
* If call frame address is in r1, no new frame was allocated.
*/
if (nops == 1 && ops[0].atom == DW_OP_bregx && ops[0].number == 1 &&
ops[0].number2 == 0)
return 1;
/*
* A new frame was allocated but has not yet been used.
*/
return 2;
}
static int
print_register (void *arg,
int regno,
const char *setname,
const char *prefix,
const char *regname,
int bits __attribute__ ((unused)),
int type __attribute__ ((unused)))
{
struct stuff *stuff = arg;
printf ("\t%s reg%u (%s%s): ", setname, regno, prefix, regname);
Dwarf_Op ops_mem[2];
Dwarf_Op *ops;
size_t nops;
int result = dwarf_frame_register (stuff->frame, regno, ops_mem, &ops, &nops);
print_detail (result, ops, nops, stuff->bias);
return DWARF_CB_OK;
}
