/* $Header$ */
/*
* (c) copyright 1987 by the Vrije Universiteit, Amsterdam, The Netherlands.
* See the copyright notice in the ACK home directory, in the file "Copyright".
*/
/* C O N T R O L F L O W
*
* M A I N R O U T I N E
*/
#include <stdio.h>
#include "../share/types.h"
#include "../share/debug.h"
#include "../share/map.h"
#include "../share/files.h"
#include "../share/global.h"
#include "../share/alloc.h"
#include "../share/lset.h"
#include "../share/cset.h"
#include "../share/get.h"
#include "../share/put.h"
#include "../../../h/em_mnem.h"
#include "../../../h/em_pseu.h"
#include "../../../h/em_spec.h"
#include "../../../h/em_flag.h"
#include "../../../h/em_mes.h"
#include "../share/def.h"
#include "cf.h"
#include "cf_succ.h"
#include "cf_idom.h"
#include "cf_loop.h"
#define newcfbx() (bext_p) newstruct(bext_cf)
#define oldcfbx(x) oldstruct(bext_cf,x)
extern char em_flag[];
STATIC cset lpi_set; /* set of procedures used in LPI instruction */
STATIC cset cai_set; /* set of all procedures doing a CAI */
/* The procedure getbblocks reads the EM textfile and
* partitions every procedure into a number of basic blocks.
*/
#define LABEL0 0
#define LABEL 1
#define NORMAL 2
#define JUMP 3
#define END 4
#define AFTERPRO 5
#define INIT 6
/* These global variables are used by getbblocks and nextblock. */
STATIC bblock_p b, *bp; /* b is the current basic block, bp is
* the address where the next block has
* to be linked.
*/
STATIC line_p lnp, *lp; /* lnp is the current line, lp is
* the address where the next line
* has to be linked.
*/
STATIC short state; /* We use a finite state machine with the
* following states:
* LABEL0: after the first (successive)
* instruction label.
* LABEL1: after at least two successive
* instruction labels.
* NORMAL: after a normal instruction.
* JUMP: after a branch (conditional,
* unconditional or CSA/CSB).
* END: after an END pseudo
* AFTERPRO: after we've read a PRO pseudo
* INIT: initial state
*/
STATIC nextblock()
{
/* allocate a new basic block structure and
* set b, bp and lp.
*/
b = *bp = freshblock();
bp = &b->b_next;
b->b_start = lnp;
b->b_succ = Lempty_set();
b->b_pred = Lempty_set();
b->b_extend = newcfbx(); /* basic block extension for CF */
b->b_extend->bx_cf.bx_bucket = Lempty_set();
b->b_extend->bx_cf.bx_semi = 0;
lp = &lnp->l_next;
#ifdef TRACE
fprintf(stderr,"new basic block, id = %d\n",lastbid);
#endif
}
STATIC short kind(lnp)
line_p lnp;
{
/* determine if lnp is a label, branch, end or otherwise */
short instr;
byte flow;
if ((instr = INSTR(lnp)) == op_lab) return (short) LABEL;
if (instr == ps_end) return (short) END;
if (instr > sp_lmnem) return (short) NORMAL; /* pseudo */
if ((flow = (em_flag[instr-sp_fmnem] & EM_FLO)) == FLO_C ||
flow == FLO_T) return (short) JUMP; /* conditional/uncond. jump */
return (short) NORMAL;
}
STATIC bool getbblocks(fp,kind_out,n_out,g_out,l_out)
FILE *fp;
short *kind_out;
short *n_out;
bblock_p *g_out;
line_p *l_out;
{
bblock_p head = (bblock_p) 0;
line_p headl = (line_p) 0;
curproc = (proc_p) 0;
/* curproc will get a value when we encounter a PRO pseudo.
* If there is no such pseudo, we're reading only data
* declarations or messages (outside any proc.).
*/
curinp = fp;
lastbid = (block_id) 0; /* block identier */
state = INIT; /* initial state */
bp = &head;
for (;;) {
#ifdef TRACE
fprintf(stderr,"state = %d\n",state);
#endif
switch(state) {
case LABEL0:
nextblock();
/* Fall through !! */
case LABEL:
lbmap[INSTRLAB(lnp)] = b;
/* The lbmap table contains for each
* label_id the basic block of that label.
*/
lnp = read_line(&curproc);
state = kind(lnp);
if (state != END) {
*lp = lnp;
lp = &lnp->l_next;
}
break;
case NORMAL:
lnp = read_line(&curproc);
if ( (state = kind(lnp)) == LABEL) {
/* If we come accross a label
* here, it must be the beginning
* of a new basic block.
*/
state = LABEL0;
} else {
if (state != END) {
*lp = lnp;
lp = &lnp->l_next;
}
}
break;
case JUMP:
lnp = read_line(&curproc);
/* fall through ... */
case AFTERPRO:
switch(state = kind(lnp)) {
case LABEL:
state = LABEL0;
break;
case JUMP:
case NORMAL:
nextblock();
break;
}
break;
case END:
*lp = lnp;
#ifdef TRACE
fprintf(stderr,"at end of proc, %d blocks\n",lastbid);
#endif
if (head == (bblock_p) 0) {
*kind_out = LDATA;
*l_out = headl;
} else {
*kind_out = LTEXT;
*g_out = head;
*n_out = (short) lastbid;
/* number of basic blocks */
}
return TRUE;
case INIT:
lnp = read_line(&curproc);
if (feof(curinp)) return FALSE;
if (INSTR(lnp) == ps_pro) {
state = AFTERPRO;
} else {
state = NORMAL;
headl = lnp;
lp = &lnp->l_next;
}
break;
}
}
}
STATIC interproc_analysis(p)
proc_p p;
{
/* Interprocedural analysis of a procedure p determines:
* - all procedures called by p (the 'call graph')
* - the set of objects changed by p (directly)
* - whether p does a load-indirect (loi,lof etc.)
* - whether p does a store-indirect (sti, stf etc.)
* The changed/used variables information will be
* transitively closed, i.e. if P calls Q and Q changes
* a variable X, the P changes X too.
* (The same applies for used variables and for use/store
* indirect).
* The transitive closure will be computed by main
* after all procedures have been processed.
*/
bblock_p b;
line_p lnp;
bool inloop;
/* Allocate memory for structs and sets */
p->p_use = newuse();
p->p_change = newchange();
p->p_change->c_ext = Cempty_set(olength);
p->p_calling = Cempty_set(plength);
for (b = p->p_start; b != (bblock_p) 0; b = b->b_next) {
inloop = (Lnrelems(b->b_loops) > 0);
for (lnp = b->b_start; lnp != (line_p) 0; lnp = lnp->l_next) {
/* for all instructions of p do */
switch(INSTR(lnp)) {
case op_cal:
Cadd(PROC(lnp)->p_id, &p->p_calling);
/* add called proc to p_calling */
if (inloop) {
CALLED_IN_LOOP(PROC(lnp));
}
break;
case op_cai:
Cadd(p->p_id,&cai_set);
break;
case op_lpi:
Cadd(PROC(lnp)->p_id, &lpi_set);
/* All procedures that have their names used
* in an lpi instruction, may be called via
* a cai instruction.
*/
PROC(lnp)->p_flags1 |= PF_LPI;
break;
case op_ste:
case op_sde:
case op_ine:
case op_dee:
case op_zre:
Cadd(OBJ(lnp)->o_id, &p->p_change->c_ext);
/* Add changed object to c_ext */
break;
case op_lil:
case op_lof:
case op_loi:
case op_los:
case op_lar:
p->p_use->u_flags |= UF_INDIR;
/* p does a load-indirect */
break;
case op_sil:
case op_stf:
case op_sti:
case op_sts:
case op_sar:
p->p_change->c_flags |= CF_INDIR;
/* p does a store-indirect */
break;
case op_blm:
case op_bls:
p->p_use->u_flags |= UF_INDIR;
p->p_change->c_flags |= CF_INDIR;
/* p does both */
break;
case op_mon:
printf("mon not yet implemented\n");
break;
case op_lxl:
case op_lxa:
curproc->p_flags1 |= PF_ENVIRON;
break;
case op_lor:
case op_str:
if (SHORT(lnp) == 0) {
curproc->p_flags1 |= PF_ENVIRON;
}
break;
case ps_mes:
if (aoff(ARG(lnp),0) == ms_gto) {
ENTERED_WITH_GTO(curproc);
}
break;
}
}
}
}
STATIC cf_cleanproc(p)
proc_p p;
{
/* Remove the extended data structures of p */
register bblock_p b;
register Lindex pi;
loop_p lp;
for (b = p->p_start; b != (bblock_p) 0; b = b->b_next) {
oldcfbx(b->b_extend);
}
for (pi = Lfirst(p->p_loops); pi != (Lindex) 0; pi = Lnext(pi,
p->p_loops)) {
lp = (loop_p) Lelem(pi);
oldcflpx(lp->lp_extend);
}
}
#define CHANGE_INDIR(ch) ((ch->c_flags & CF_INDIR) != 0)
#define USE_INDIR(us) ((us->u_flags & UF_INDIR) != 0)
#define CALLS_UNKNOWN(p) (p->p_flags1 & (byte) PF_CALUNKNOWN)
#define BODY_KNOWN(p) (p->p_flags1 & (byte) PF_BODYSEEN)
#define ENVIRON(p) (p->p_flags1 & (byte) PF_ENVIRON)
STATIC bool add_info(q,p)
proc_p q,p;
{
/* Determine the consequences for used/changed variables info
* of the fact that p calls q. If e.g. q changes a variable X
* then p changes this variable too. This routine is an
* auxiliary routine of the transitive closure process.
* The returned value indicates if there was any change in
* the information of p.
*/
change_p chp, chq;
use_p usp, usq;
bool diff = FALSE;
chp = p->p_change;
chq = q->p_change;
usp = p->p_use;
usq = q->p_use;
if (!BODY_KNOWN(q)) {
/* q is a procedure of which the body is not available
* as EM text.
*/
if (CALLS_UNKNOWN(p)) {
return FALSE;
/* p already called an unknown procedure */
} else {
p->p_flags1 |= PF_CALUNKNOWN;
return TRUE;
}
}
if (CALLS_UNKNOWN(q)) {
/* q calls a procedure of which the body is not available
* as EM text.
*/
if (!CALLS_UNKNOWN(p)) {
p->p_flags1 |= PF_CALUNKNOWN;
diff = TRUE;
}
}
if (IS_CALLED_IN_LOOP(p) && !IS_CALLED_IN_LOOP(q)) {
CALLED_IN_LOOP(q);
diff = TRUE;
}
if (!Cis_subset(chq->c_ext, chp->c_ext)) {
/* q changes global variables (objects) that
* p did not (yet) change. Add all variables
* changed by q to the c_ext set of p.
*/
Cjoin(chq->c_ext, &chp->c_ext);
diff = TRUE;
}
if (CHANGE_INDIR(chq) && !CHANGE_INDIR(chp)) {
/* q does a change-indirect (sil etc.)
* and p did not (yet).
*/
chp->c_flags |= CF_INDIR;
diff = TRUE;
}
if (USE_INDIR(usq) && !USE_INDIR(usp)) {
/* q does a use-indirect (lil etc.)
* and p dis not (yet).
*/
usp->u_flags |= UF_INDIR;
diff = TRUE;
}
if (ENVIRON(q) && !ENVIRON(p)) {
/* q uses or changes local variables in its
* environment while p does not (yet).
*/
p->p_flags1 |= PF_ENVIRON;
diff = TRUE;
}
return diff;
}
STATIC trans_clos(head)
proc_p head;
{
/* Compute the transitive closure of the used/changed
* variable information.
*/
register proc_p p,q;
Cindex i;
bool changes = TRUE;
while(changes) {
changes = FALSE;
for (p = head; p != (proc_p) 0; p = p->p_next) {
if (!BODY_KNOWN(p)) continue;
for (i = Cfirst(p->p_calling); i != (Cindex) 0;
i = Cnext(i,p->p_calling)) {
q = pmap[Celem(i)];
if (add_info(q,p)) {
changes = TRUE;
}
}
}
}
}
indir_calls()
{
Cindex i;
proc_p p;
for (i = Cfirst(cai_set); i != (Cindex) 0; i = Cnext(i,cai_set)) {
p = pmap[Celem(i)]; /* p does a CAI */
Cjoin(lpi_set, &p->p_calling);
}
Cdeleteset(lpi_set);
Cdeleteset(cai_set);
}
main(argc,argv)
int argc;
char *argv[];
{
FILE *f, *f2, *gf2; /* The EM input, EM output, basic block output */
bblock_p g;
short n, kind;
line_p l;
linecount = 0;
fproc = getptable(pname); /* proc table */
fdblock = getdtable(dname); /* data block table */
lpi_set = Cempty_set(plength);
cai_set = Cempty_set(plength);
if ((f = fopen(lname,"r")) == NULL) {
error("cannot open %s", lname);
}
if ((f2 = fopen(lname2,"w")) == NULL) {
error("cannot open %s", lname2);
}
if ((gf2 = fopen(bname2,"w")) == NULL) {
error("cannot open %s",bname2);
}
while (getbblocks(f,&kind,&n,&g,&l)) {
/* read EM text of one unit and
* (if it is a procedure)
* partition it into n basic blocks.
*/
if (kind == LDATA) {
putunit(LDATA,(proc_p) 0,l,gf2,f2);
} else {
curproc->p_start = g;
/* The global variable curproc points to the
* current procedure. It is set by getbblocks
*/
control_flow(g); /* compute pred and succ */
dominators(g,n); /* compute immediate dominators */
loop_detection(curproc); /* compute loops */
interproc_analysis(curproc);
/* Interprocedural analysis */
cf_cleanproc(curproc);
putunit(LTEXT,curproc,(line_p) 0,gf2,f2);
/* output control flow graph + text */
}
}
fclose(f);
fclose(f2);
fclose(gf2);
indir_calls();
trans_clos(fproc);
/* Compute transitive closure of used/changed
* variables information for every procedure.
*/
if ((f = fopen(dname2,"w")) == NULL) {
error("cannot open %s",dname2);
}
putdtable(fdblock,f);
if ((f = fopen(pname2,"w")) == NULL) {
error("cannot open %s",pname2);
}
putptable(fproc,f,TRUE);
exit(0);
}