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/*
Crown Copyright (c) 1997
This TenDRA(r) Computer Program is subject to Copyright
owned by the United Kingdom Secretary of State for Defence
acting through the Defence Evaluation and Research Agency
(DERA). It is made available to Recipients with a
royalty-free licence for its use, reproduction, transfer
to other parties and amendment for any purpose not excluding
product development provided that any such use et cetera
shall be deemed to be acceptance of the following conditions:-
(1) Its Recipients shall ensure that this Notice is
reproduced upon any copies or amended versions of it;
(2) Any amended version of it shall be clearly marked to
show both the nature of and the organisation responsible
for the relevant amendment or amendments;
(3) Its onward transfer from a recipient to another
party shall be deemed to be that party's acceptance of
these conditions;
(4) DERA gives no warranty or assurance as to its
quality or suitability for any purpose and DERA accepts
no liability whatsoever in relation to any use to which
it may be put.
*/
/**********************************************************************
$Author: release $
$Date: 1998/01/17 15:56:06 $
$Revision: 1.1.1.1 $
$Log: locate.c,v $
* Revision 1.1.1.1 1998/01/17 15:56:06 release
* First version to be checked into rolling release.
*
* Revision 1.3 1995/09/12 10:59:30 currie
* gcc pedanttry
*
* Revision 1.2 1995/08/16 16:06:50 currie
* Shortened some .h names
*
* Revision 1.1 1995/04/13 09:08:06 currie
* Initial revision
*
***********************************************************************/
/* locate.c
discovers "where" an "exp" is;
The where coding of an address tells one whether the result of
evaluating an exp is in a register or directly or literally in store,
*/
#include "config.h"
#include "addrtypes.h"
#include "expmacs.h"
#include "tags.h"
#include "inst_fmt.h"
#include "mips_ins.h"
#include "bitsmacs.h"
#include "exp.h"
#include "procrectypes.h"
#include "guard.h"
#include "eval.h"
#include "regexps.h"
#include "shapemacs.h"
#include "psu_ops.h"
#include "getregs.h"
#include "move.h"
#include "handle_sregs.h"
#include "common_types.h"
#include "frames.h"
#include "code_here.h"
#include "locate.h"
#include "basicread.h"
extern FILE * as_file;
long locals_offset; /* the offset in bits of start of current
locals */
long frame_size; /* the size of the current stack frame in
bits */
baseoff boff
PROTO_N ( (id) )
PROTO_T ( exp id )
{ /* decodes id to give a baseoff suitable
for ls_ins etc */
baseoff an;
if (isglob (id)) { /* globals */
dec * gl = brog(id);
long sno = gl->dec_u.dec_val.sym_number;
an.base = -(sno + 1);
an.offset = 0;
}
else {
int x = no (id);
int b = x & 0x3f;
if (name(son(id))==caller_name_tag) {
an.base = 29;
an.offset = (x-b)>>4;
/* caller tags */
}
else
if (b == 29) {
an.base = 29;
an.offset = ((x - b) >> 4) + (locals_offset >> 3);
/* locally declared things accessed by sp*/
}
else
if ((b==30 && Has_fp) ) {
an.base = b;
an.offset = (((x - b)) >> 4) + (locals_offset >> 3)
- ((frame_size+callee_size)>>3);
/* locally declared things accessed by fp */
}
else
if ( (b == local_reg && Has_vcallees)) {
an.base = b;
an.offset = (((x - b)) >> 4) + (locals_offset >> 3)
- (frame_size>>3);
/* locally declared things accessed by local_reg */
}
else
if (b <= 31) {
an.base = b;
an.offset = ((x - b) >> 4);
/* other base offsets */
}
else
if (b == 32) {
an.base = -((x - b) >> 6);
an.offset = 0;
/* global names */
}
else
if (b == 33) {
an.base = (x - b) >> 6;
an.offset = 0;
/* global anonymous */
}
else {
failer ("not a baseoff in boff ");
}
}
return an;
}
where locate PROTO_S ((exp e, space sp, shape s, int dreg));
/* locate differs from locate1 only in that it looks to see e has already
been evaluated somehow */
where locate1
PROTO_N ( (e, sp, s, dreg) )
PROTO_T ( exp e X space sp X shape s X int dreg )
{
/* finds the address of e using shape s;
sp gives available t-regs for any inner
evaluation. dreg is historical. */
ash a;
ans aa;
where wans;
a = ashof (s);
/* while (name (e) == diag_tag || name (e) == fscope_tag
|| name (e) == cscope_tag) {
e = son (e);
}
*/
switch (name (e)) {
case name_tag:
{
exp decx = son (e);
bool var = isvar (decx);
/* this a locally declared name ... */
if (props (decx) & defer_bit) {
/* ... it has been identified with a
simple expression which is better
evaluated every time */
where w;
w = locate (son (decx), sp, sh (son (decx)), dreg);
if (no (e) == 0) {
aa = w.answhere;
}
else {
instore is;
switch (w.answhere.discrim) {
case notinreg:
{
is = insalt (w.answhere);
is.b.offset += (no (e) / 8);
break;
}
default:
failer ("NOT deferable");
}
setinsalt (aa, is);
}
}
else
if (props (decx) & inreg_bits) {
/* ... it has been allocated in a fixed
point reg */
if (var) {
setregalt (aa, no (decx));
}
else {
instore b;
b.b.base = no (decx);
b.b.offset = 0;
b.adval = 1;
setinsalt (aa, b);
}
}
else
if (props (decx) & infreg_bits) {
/* ... it has been allocated in a floating
point reg */
freg fr;
fr.fr = no (decx);
fr.dble = (a.ashsize == 64) ? 1 : 0;
setfregalt (aa, fr);
}
else { /* ... it is in memory */
instore is;
if (var || (name (sh (e)) == prokhd &&
(son (decx) == nilexp || name (son (decx)) == proc_tag
|| name (son (decx)) == general_proc_tag))) {
is.adval = 1;
}
else {
is.adval = 0;
}
is.b = boff (decx);
is.b.offset += (no (e) / 8);
setinsalt (aa, is);
}
wans.answhere = aa;
wans.ashwhere = a;
return wans;
}
case addptr_tag:
{
exp sum = son (e);
where wsum;
int addend;
space nsp;
int reg;
int ind;
instore is;
ans asum;
wsum = locate (sum, sp, sh (sum), 0);
asum = wsum.answhere;
/* answer is going to be wsum displaced by integer result of
evaluating bro(sum) */
switch (asum.discrim) {
case notinreg:
{
is = insalt (asum);
if (is.adval) { /* wsum is a literal address in store ...
*/
baseoff b;
b = is.b;
if (b.base < 0 || b.base > 31) {
/* ... it is not a base-offset , so make
it one */
reg = getreg (sp.fixed);
ls_ins (i_la, reg, b);
keepreg (sum, reg);
b.base = reg;
b.offset = 0;
}
nsp = guardreg (b.base, sp);
addend = reg_operand (bro (sum), nsp);
/* evaluate the displacement ... */
if (dreg == 0)
dreg = getreg (nsp.fixed);
rrr_ins (i_addu, dreg, b.base, addend);
/* ... add it to the base register into new reg */
b.base = dreg;
is.b = b;
setinsalt (aa, is);
wans.answhere = aa;
wans.ashwhere = a;
/* ...and use it as base a literal base-offset result */
keepexp (e, aa);
return wans;
}
else { /* wsum represents an actual pointer in
store... */
ind = getreg (sp.fixed);
ls_ins (i_lw, ind, is.b);
/* ... so load it into a good register */
}
goto breakpt;
/* should be break - thought there was cc error */
} /* end notinreg */
case inreg:
/* wsum is already in reg */
{
ind = regalt (asum);
goto breakpt;
}
default: {
failer ("Locate ? reg");
}
} /* end case */
breakpt: /* register ind contains the evaluation of
1st operand of addptr */
nsp = guardreg (ind, sp);
if (name(bro(sum)) == env_offset_tag
|| name(bro(sum)) == general_env_offset_tag ) {
is.b.base = ind;
is.b.offset = frame_offset(son(bro(sum)));
}
else {
addend = reg_operand (bro (sum), nsp);
/* evaluate displacement .... */
if (dreg == 0)
dreg = getreg (nsp.fixed);
rrr_ins (i_addu, dreg, ind, addend);
/* ... add it to ind in new reg */
is.b.base = dreg;
is.b.offset = 0;
}
is.adval = 1;
setinsalt (aa, is);
wans.answhere = aa;
wans.ashwhere = a;
/* ... and deliver literal base_offset */
keepexp (e, aa);
return wans;
} /* end add_ptr */
case subptr_tag: /* this is nugatory - previous transforms
make it into addptr or reff */
{
exp sum = son (e);
int ind = reg_operand (sum, sp);
instore isa;
isa.adval = 1;
sum = bro (sum);
if (name (sum) == val_tag) {
instore isa;
isa.b.base = ind;
isa.b.offset = -no (e);
setinsalt (aa, isa);
}
else {
if (dreg == 0)
dreg = getreg (sp.fixed);
rrr_ins (i_subu, dreg, ind,
reg_operand (sum, guardreg (ind, sp)));
isa.b.base = dreg;
isa.b.offset = 0;
}
setinsalt (aa, isa);
wans.answhere = aa;
wans.ashwhere = a;
keepexp (e, aa);
return wans;
} /* end subptr */
case reff_tag: {
instore isa;
wans = locate (son (e), sp, sh (son (e)), 0);
/* answer is going to be wans displaced by no(e) */
switch (wans.answhere.discrim) {
case notinreg: {
isa = insalt (wans.answhere);
if (!isa.adval) {
/* wans is an actual pointer in store, so make it into a
literal address.... */
int reg = getreg (sp.fixed);
ls_ins (i_lw, reg, isa.b);
isa.b.offset = 0;
isa.b.base = reg;
isa.adval = 1;
}
/* ... and add appropriate displacement to give result */
isa.b.offset += no (e) / 8;
setinsalt (wans.answhere, isa);
keepexp (e, wans.answhere);
break;
}
case inreg: {
/* wans is a pointer in a register */
isa.b.base = regalt (wans.answhere);
isa.adval = 1;
isa.b.offset = no (e) / 8;
setinsalt (wans.answhere, isa);
break;
}
default: {
failer ("Locate ? reg ");
}
}
wans.ashwhere = a;
return wans;
} /* end reff */
case cont_tag:
case contvol_tag:
{
exp s = son (e);
ans ason;
instore isa;
int reg;
where fc;
fc = locate (s, sp, sh (e), 0);
ason = fc.answhere;
/* answer is going to be the contents of address represented by fc
*/
switch (ason.discrim) {
case notinreg:
{
isa = insalt (ason);
if (isa.adval) { /* fc is a literal store address, so make
it into a direct one */
isa.adval = 0;
setinsalt (aa, isa);
}
else { /* fc is an actual pointer in store ....
*/
reg = getreg (sp.fixed);
ls_ins (i_lw, reg, isa.b);
/* .... so load it into reg and deliver direct base-offset
(reg,0) */
isa.b.base = reg;
isa.b.offset = 0;
setinsalt (aa, isa);
if (name (e) != contvol_tag && fc.ashwhere.ashalign != 1)
keepexp (e, aa);
}
goto breakson;
} /* end notinrg */
case inreg:
/* this one is fraught - it depends on only being used in
lh-value positions from vars- take care */
{
isa.b.base = regalt (ason);
isa.b.offset = 0;
isa.adval = 1;
setinsalt (aa, isa);
/* fc is in register, so deliver literal(!? ) base-offset */
goto breakson;
}
case infreg: /* ditto caveat above */
{
aa = ason;
goto breakson;
}
default: {
failer ("Locate ? reg");
}
}
breakson:
wans.answhere = aa;
wans.ashwhere = a;
return wans;
} /* end cont */
case top_tag: /* does this ever happen ? */
{
setregalt (aa, 0);
wans.answhere = aa;
wans.ashwhere = a;
return wans;
} /* end top */
case field_tag: {
instore isa;
wans = locate (son (e), sp, sh (son (e)), 0);
/* answer is wans displace literally by no(e); it should always be
a literal store adress */
switch (wans.answhere.discrim) {
case notinreg: {
isa = insalt (wans.answhere);
isa.b.offset += no (e) / 8;
setinsalt (wans.answhere, isa);
break;
}
default:
failer (" field should be transformed ");
}
wans.ashwhere = a;
return wans;
} /* end field */
default:
/* general catch all; evaluate e into register and deliver it as a
literal store address */
{
int r = reg_operand (e, sp);
instore is;
if (r == 2) { /* guard possible result from proc - can
do better */
r = getreg (sp.fixed);
mon_ins (i_move, r, 2);
}
is.b.base = r;
is.b.offset = 0;
is.adval = 1;
setinsalt (aa, is);
wans.answhere = aa;
wans.ashwhere = a;
return wans;
}
}
}
where locate
PROTO_N ( (e, sp, s, dreg) )
PROTO_T ( exp e X space sp X shape s X int dreg )
{
ans ak;
where w;
ak = iskept (e);
if (ak.discrim == inreg && (regalt (ak) == 0)) {
where w;
w = locate1 (e, sp, s, dreg);
return w;
}
else { /* e has been evaluated into a register */
w.answhere = ak;
w.ashwhere = ashof (s);
}
return w;
}