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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.
*/
/*
$Log: tempdecs.c,v $
* Revision 1.1.1.1 1998/01/17 15:56:03 release
* First version to be checked into rolling release.
*
* Revision 1.2 1995/12/18 13:12:40 wfs
* Put hppatrans uder cvs control. Major Changes made since last release
* include:
* (i) PIC code generation.
* (ii) Profiling.
* (iii) Dynamic Initialization.
* (iv) Debugging of Exception Handling and Diagnostics.
*
* Revision 5.2 1995/10/20 14:14:22 wfs
* #included "muldvrem.h" for gcc compilation.
*
* Revision 5.1 1995/09/07 15:44:58 wfs
* Fixed bug in "APPLYLIKE".
*
* Revision 5.0 1995/08/25 13:42:58 wfs
* Preperation for August 25 Glue release
*
* Revision 3.4 1995/08/25 10:34:20 wfs
* Refinement of "APPLYLIKE" required for 3.1 and 4.0 compatability
*
* Revision 3.4 1995/08/25 10:34:20 wfs
* Refinement of "APPLYLIKE" required for 3.1 and 4.0 compatability
*
* Revision 3.1 95/04/10 16:28:30 16:28:30 wfs (William Simmonds)
* Apr95 tape version.
*
* Revision 3.0 95/03/30 11:19:06 11:19:06 wfs (William Simmonds)
* Mar95 tape version with CRCR95_178 bug fix.
*
* Revision 2.0 95/03/15 15:28:59 15:28:59 wfs (William Simmonds)
* spec 3.1 changes implemented, tests outstanding.
*
* Revision 1.1 95/01/11 13:19:10 13:19:10 wfs (William Simmonds)
* Initial revision
*
*/
#define HPPATRANS_CODE
/* tempdec.c - is the value in the declaration required over proc calls ?
if it isn't, declaration can be allocated in t-reg, rather than
s-reg.
*/
#include "config.h"
#include "tags.h"
#include "common_types.h"
#include "exp.h"
#include "const.h"
#include "expmacs.h"
#include "bitsmacs.h"
#include "muldvrem.h"
#include "tempdecs.h"
/*
IS THE EXPRESSION e A PROCEDURE APPLICATION?
*/
#define APPLYLIKE( e ) ( name(e)==apply_tag || name(e)==apply_general_tag ||\
name(e)==tail_call_tag || is_muldivrem_call(e) )
/*
FLAG : APPLY TEMPDEF OPTIMISATION?
*/
bool tempdecopt ; /* flag to allow this optimisation, set in main () */
/*
VARIABLES SET BY TRACE_USES
*/
static int nouses ;
static bool useinpar ;
/*
Reduces nouses for each non-assignment use of id encountered in e,
sets useinpar if use in actual parameter (or function) position,
terminates with 0 on applications or jumps, terminates with 2 on
assignment to id, otherwise delivers 1.
*/
int trace_uses
PROTO_N ( ( e, id ) )
PROTO_T ( exp e X exp id )
{
if ( APPLYLIKE ( e ) ) {
int u = nouses ;
int p = 1 ;
exp l = son ( e ) ;
while ( p == 1 ) {
p = trace_uses ( l, id ) ;
if ( u != nouses || p == 2 ) useinpar = 1 ;
if ( p == 0 ) nouses = u ;
if ( last ( l ) ) break ;
l = bro ( l ) ;
}
return ( 0 ) ;
}
switch ( name ( e ) ) {
case env_offset_tag:
case name_tag : {
nouses -= ( son ( e ) == id ? 1 : 0 ) ;
return ( 1 ) ;
}
case ident_tag : {
exp f = son ( e ) ;
exp s = bro ( f ) ;
int a ;
if ( ( props ( e ) & defer_bit ) != 0 ) {
exp t = f ;
f = s ;
s = t ;
}
a = trace_uses ( f, id ) ;
if ( a != 1 ) return ( a ) ;
return ( trace_uses ( s, id ) ) ;
}
case case_tag : {
trace_uses ( son ( e ), id ) ;
return ( 0 ) ;
}
case labst_tag : {
return ( 0 ) ;
}
case seq_tag : {
exp s = son ( son ( e ) ) ;
for ( ; ; ) {
int el = trace_uses ( s, id ) ;
if ( el != 1 ) return ( el ) ;
if ( last ( s ) ) {
return ( trace_uses ( bro ( son ( e ) ), id ) ) ;
}
s = bro ( s ) ;
}
/* NOT REACHED */
break ;
}
case test_tag: case goto_lv_tag:{
int nu = nouses;
if (trace_uses(son(e),id) != 1 ||
trace_uses(bro(son(e)), id) !=1 ){
nouses = nu;
}
return 0;
}
case ass_tag : {
if ( isvar ( id ) && name ( son ( e ) ) == name_tag &&
son ( son ( e ) ) == id ) {
trace_uses ( bro ( son ( e ) ), id ) ;
return ( 2 ) ;
} else if ( APPLYLIKE ( bro ( son ( e ) ) ) ) {
return ( trace_uses ( bro ( son ( e ) ), id ) ) ;
}
/* Fall through */
}
default : {
exp s = son ( e ) ;
int nu = nouses ; /* s list can be done in any order ... */
if ( s == nilexp ) return ( 1 ) ;
for ( ; ; ) {
int el = trace_uses ( s, id ) ;
if ( el != 1 ) {
/* ... so reset nouses if any terminate */
nouses = nu ;
return el ;
}
if ( last ( s ) ) return ( 1 ) ;
s = bro ( s ) ;
}
/* NOT REACHED */
break ;
}
}
/* NOT REACHED */
return ( 0 ) ;
}
/*
APPLY TRACE_USES TO DYNAMIC SUCCESSORS OF a
*/
void after_a
PROTO_N ( ( a, id ) )
PROTO_T ( exp a X exp id )
{
char n ;
exp dad ;
exp l ;
tailrec : {
dad = father ( a ) ;
n = name ( dad ) ;
if ( nouses == 0 ) return ;
if ( n == cond_tag || n == rep_tag || n == solve_tag ||
n == labst_tag || n == case_tag || n == goto_tag ||
n == test_tag || n == goto_lv_tag || APPLYLIKE ( dad ) ) {
/* Don't try too hard! */
while ( APPLYLIKE ( dad ) && dad != id ) dad = father ( dad ) ;
if ( APPLYLIKE ( dad ) ) {
useinpar = 1 ;
}
return ;
}
for ( l = a ; !last ( l ) ; l = bro ( l ) )
{
int u = trace_uses ( bro ( l ), id ) ;
if ( u != 1 || nouses == 0 ) return ;
}
a = dad ;
}
if ( dad != id ) goto tailrec ;
return ;
}
bool simple_seq
PROTO_N ( ( e, id ) )
PROTO_T ( exp e X exp id )
{
exp dad = father ( e ) ;
for ( ; ; ) {
if ( dad == id ) return ( 1 ) ;
if ( name ( dad ) == seq_tag || name ( dad ) == 0 ||
name ( dad ) == ident_tag ) {
dad = father ( dad ) ;
} else {
return ( 0 ) ;
}
}
/* NOT REACHED */
}
bool tempdec
PROTO_N ( ( e, enoughs ) )
PROTO_T ( exp e X bool enoughs )
{
/*
* e is a local declaration ; 'enoughs' is a misnomer to say whether there
* are t-regs available delivers 1 if e can be allocated into t-reg or par
* reg
*/
exp p ;
if ( !tempdecopt ) return ( 0 ) ;
nouses = 0 ;
useinpar = 0 ;
if ( isvar ( e ) ) {
for ( p = pt ( e ) ; p != nilexp ; p = pt ( p ) ) {
/* find no of uses which are not assignments to id ... */
if ( !last ( p ) && last ( bro ( p ) ) &&
name ( bro ( bro ( p ) ) ) == ass_tag ) {
if ( !simple_seq ( bro ( bro ( p ) ), e ) ) return ( 0 ) ;
/* ... in simple sequence */
continue ;
}
nouses++ ;
}
} else {
nouses = no ( e ) ;
}
/*
* trace simple successors to assignmnts or init to id to find if all uses
* occur before unpredictable change of control ( or another assignment to
* id )
*/
if ( name ( son ( e ) ) != clear_tag || isparam ( e ) ) {
after_a ( son ( e ), e ) ;
}
if ( isvar ( e ) ) {
for ( p = pt ( e ) ; p != nilexp ; p = pt ( p ) ) {
if ( !last ( p ) && last ( bro ( p ) ) &&
name ( bro ( bro ( p ) ) ) == ass_tag ) {
after_a ( bro ( bro ( p ) ), e ) ;
}
}
}
if ( nouses == 0 && ( enoughs || !useinpar ) ) {
#if 0
/* +++ temp circumvention, we need to calculate t-reg reqt better when
some not allowed by props ( e ) |= notparreg */
if ( useinpar ) return ( 0 ) ;
#else
if ( useinpar ) props ( e ) |= notparreg ; /* don't allocate this into par reg */
#endif
return ( 1 ) ;
}
return ( 0 ) ;
}