381 lines
7.6 KiB
C
381 lines
7.6 KiB
C
/* $Id$ */
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/*
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* (c) copyright 1987 by the Vrije Universiteit, Amsterdam, The Netherlands.
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* See the copyright notice in the ACK home directory, in the file "Copyright".
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*/
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/* U S E - D E F I N I T I O N A N A L Y S I S
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*
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* U D _ D E F S . C
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*/
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#include <em_mnem.h>
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#include "../share/types.h"
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#include "ud.h"
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#include "../share/debug.h"
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#include "../share/global.h"
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#include "../share/lset.h"
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#include "../share/cset.h"
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#include "../share/map.h"
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#include "../share/locals.h"
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#include "ud_defs.h"
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#include "../share/alloc.h"
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#include "../share/utils.h"
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short nrdefs; /* total number of definitions */
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short nrexpldefs; /* number of explicit definitions */
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line_p *defs;
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cset *vardefs;
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STATIC cset all_globl_defs, all_indir_defs;
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/* auxiliary sets, used by gen_sets */
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bool does_expl_def(l)
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line_p l;
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{
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/* See if instruction l does an explicit definition */
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switch(INSTR(l)) {
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case op_stl:
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case op_sdl:
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case op_ste:
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case op_sde:
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case op_inl:
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case op_del:
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case op_ine:
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case op_dee:
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case op_zrl:
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case op_zre:
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return TRUE;
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default:
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return FALSE;
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}
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/* NOTREACHED */
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}
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bool does_impl_def(l)
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line_p l;
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{
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/* See if instruction l does an implicit definition */
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switch(INSTR(l)) {
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case op_cal:
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case op_cai:
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case op_sil:
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case op_stf:
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case op_sti:
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case op_sts:
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case op_sdf:
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case op_sar:
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case op_blm:
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case op_bls:
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case op_zrf:
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return TRUE;
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default:
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return FALSE;
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}
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}
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make_defs(p)
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proc_p p;
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{
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/* Make a map of all explicit definitions
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* occurring in p.
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* Determine the set of explicit definitions
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* of variable v (i.e. vardefs[v]), for all
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* v from 1 to nrvars.
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* For every basic block b, compute CHGVARS(b),
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* i.e. the set of variables changed in b by an
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* explicit definition.
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*/
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register bblock_p b;
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register line_p l;
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short v, i, cnt = 0;
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bool found;
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/* first count the number of definitions */
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for (b = p->p_start; b != (bblock_p) 0; b = b->b_next) {
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for (l = b->b_start; l != (line_p) 0 ; l = l->l_next) {
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if (does_expl_def(l)) {
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var_nr(l,&v,&found);
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if (!found) continue; /* no ud for this var */
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cnt++;
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}
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}
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}
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nrexpldefs = cnt;
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/* now allocate the defs table and the vardefs table*/
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defs = (line_p *) newmap(nrexpldefs);
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vardefs = (cset *) newmap(nrvars);
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for (i = 1; i <= nrvars; i++) {
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vardefs[i] = Cempty_set(nrexpldefs);
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}
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cnt = 1;
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for (b = p->p_start; b != (bblock_p) 0; b = b->b_next) {
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CHGVARS(b) =Cempty_set(nrvars);
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for (l = b->b_start; l != (line_p) 0 ; l = l->l_next) {
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if (does_expl_def(l)) {
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var_nr(l,&v,&found);
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if (!found) continue;
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assert (v <= nrvars);
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Cadd(v,&CHGVARS(b));
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defs[cnt] = l;
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Cadd(cnt,&vardefs[v]);
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cnt++;
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}
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}
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}
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}
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STATIC init_gen(nrdefs)
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short nrdefs;
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{
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/* Initializing routine of gen_sets. Compute the set
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* of all implicit definitions to global variables
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* (all_globl_defs) and the set of all implicit
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* definition generated by an indirect assignment
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* through a pointer (all_indir_defs).
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*/
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short v;
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all_globl_defs = Cempty_set(nrdefs);
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all_indir_defs = Cempty_set(nrdefs);
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for (v = 1; v <= nrglobals; v++) {
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Cadd(IMPLICIT_DEF(GLOB_TO_VARNR(v)), &all_globl_defs);
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Cadd(IMPLICIT_DEF(GLOB_TO_VARNR(v)), &all_indir_defs);
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}
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for (v = 1; v <= nrlocals; v++) {
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if (!IS_REGVAR(locals[v])) {
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Cadd(IMPLICIT_DEF(LOC_TO_VARNR(v)), &all_indir_defs);
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}
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}
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}
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STATIC clean_gen()
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{
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Cdeleteset(all_globl_defs);
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Cdeleteset(all_indir_defs);
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}
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STATIC bool same_target(l,defnr)
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line_p l;
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short defnr;
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{
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/* See if l defines the same variable as def */
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line_p def;
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short v;
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if (IS_IMPL_DEF(defnr)) {
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/* An implicitly generated definition */
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v = IMPL_VAR(TO_IMPLICIT(defnr));
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if (IS_GLOBAL(v)) {
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return TYPE(l) == OPOBJECT &&
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OBJ(l)->o_globnr == TO_GLOBAL(v);
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} else {
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return TYPE(l) != OPOBJECT &&
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locals[TO_LOCAL(v)]->lc_off == off_set(l);
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}
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}
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/* explicit definition */
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def = defs[TO_EXPLICIT(defnr)];
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if (TYPE(l) == OPOBJECT) {
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return TYPE(def) == OPOBJECT && OBJ(def) == OBJ(l);
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} else {
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return TYPE(def) != OPOBJECT && off_set(def) == off_set(l);
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}
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}
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STATIC rem_prev_defs(l,gen_p)
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line_p l;
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cset *gen_p;
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{
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/* Remove all definitions in gen that define the
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* same variable as l.
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*/
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cset gen;
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Cindex i,next;
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gen = *gen_p;
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for (i = Cfirst(gen); i != (Cindex) 0; i = next) {
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next = Cnext(i,gen);
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if (same_target(l,Celem(i))) {
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Cremove(Celem(i),gen_p);
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}
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}
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}
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STATIC impl_globl_defs(p,gen_p)
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proc_p p;
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cset *gen_p;
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{
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/* Add all definitions of global variables
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* that are generated implicitly by a call
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* to p to the set gen_p.
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*/
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Cindex i;
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short v;
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cset ext = p->p_change->c_ext;
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for (i = Cfirst(ext); i != (Cindex) 0; i = Cnext(i,ext)) {
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if (( v = omap[Celem(i)]->o_globnr) != (short) 0) {
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/* the global variable v, for which we do
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* maintain ud-info is changed by p, so a
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* definition of v is generated implicitly.
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*/
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Cadd(IMPLICIT_DEF(GLOB_TO_VARNR(v)),gen_p);
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}
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}
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}
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STATIC void impl_gen_defs(l,gen_p)
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line_p l;
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cset *gen_p;
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{
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/* Add all definitions generated implicitly by instruction l
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* to gen_p. l may be a call or some kind of indirect
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* assignment.
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*/
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proc_p p;
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switch(INSTR(l)) {
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case op_cal:
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p = PROC(l);
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if (BODY_KNOWN(p)) {
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impl_globl_defs(p,gen_p);
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if (!CHANGE_INDIR(p)) return;
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break;
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}
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/* else fall through ... */
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case op_cai:
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/* Indirect subroutine call or call to
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* a subroutine whose body is not available.
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* Assume worst case; all global
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* variables are changed and
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* the called proc. does a store-
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* indirect.
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*/
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Cjoin(all_globl_defs,gen_p);
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break;
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/* default: indir. assignment */
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}
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Cjoin(all_indir_defs,gen_p);
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}
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gen_sets(p)
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proc_p p;
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{
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/* Compute for every basic block b of p the
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* set GEN(b) of definitions in b (explicit as
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* well as implicit) that reach the end of b.
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*/
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register bblock_p b;
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register line_p l;
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short defnr = 1;
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init_gen(nrdefs); /* compute all_globl_defs and all_indir_defs */
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for (b = p->p_start; b != (bblock_p) 0; b = b->b_next) {
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GEN(b) = Cempty_set(nrdefs);
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for (l = b->b_start; l != (line_p) 0; l = l->l_next) {
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if (does_impl_def(l)) {
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impl_gen_defs(l,&GEN(b));
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/* add definitions implicitly
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* generated by subroutine call
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* or indir. pointer assignment.
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*/
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} else {
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if (does_expl_def(l)) {
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if (defnr <= nrdefs && defs[defnr] == l) {
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rem_prev_defs(l,&GEN(b));
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/* previous defs. of same var
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* don't reach the end of b.
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*/
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Cadd(EXPL_TO_DEFNR(defnr),&GEN(b));
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defnr++;
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}
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}
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}
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}
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}
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clean_gen(); /* clean up */
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}
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STATIC killed_defs(v,b)
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short v;
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bblock_p b;
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{
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/* Put all definitions of v occurring outside b
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* in KILL(b). In fact, we also put explicit
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* definitions occurring in b, but not reaching the
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* end of b, in KILL(b). This causes no harm.
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*/
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Cindex i;
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short d;
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for (i = Cfirst(vardefs[v]); i != (Cindex) 0; i = Cnext(i,vardefs[v])) {
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d = Celem(i); /* d is an explicit definition of v */
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if (!Cis_elem(EXPL_TO_DEFNR(d),GEN(b))) {
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Cadd(EXPL_TO_DEFNR(d),&KILL(b));
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}
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}
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/* Also add implicit definition of v to KILL(b) */
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Cadd(IMPLICIT_DEF(v),&KILL(b));
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}
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kill_sets(p)
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proc_p p;
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{
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/* For every basic block b of p compute the set
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* KILL(b) of definitions outside b that define
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* variables redefined by b.
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* KILL(b) contains explicit as well as implicit
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* definitions.
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*/
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register bblock_p b;
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Cindex i;
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short v;
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for (b = p->p_start; b != (bblock_p) 0; b = b->b_next) {
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KILL(b) = Cempty_set(nrdefs);
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for (i = Cfirst(CHGVARS(b)); i != (Cindex) 0;
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i = Cnext(i,CHGVARS(b))) {
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v = Celem(i); /* v is a variable changed in b */
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killed_defs(v,b);
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}
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}
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}
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