731 lines
15 KiB
C
731 lines
15 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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/* I N L I N E S U B S T I T U T I O N
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*
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* I L 2 _ A U X . C
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*/
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#include <stdio.h>
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#include <em_spec.h>
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#include <em_mnem.h>
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#include "../share/types.h"
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#include "il.h"
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#include "../share/debug.h"
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#include "../share/alloc.h"
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#include "../share/global.h"
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#include "../share/lset.h"
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#include "il_aux.h"
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#include "il2_aux.h"
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#include "../share/get.h"
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#include "../share/aux.h"
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#define USE_INDIR(p) (p->p_use->u_flags & UF_INDIR)
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#define OFTEN_USED(f) ((f->f_flags&FF_OFTENUSED) == FF_OFTENUSED)
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#define CHANGE_EXT(p) (Cnrelems(p->p_change->c_ext) > 0)
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#define NOT_INLINE(a) (a->ac_inl = FALSE)
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#define INLINE(a) (a->ac_inl = TRUE)
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#define CHANGED(p) p->p_flags2 |= PF_CHANGED
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#define IS_CHANGED(p) (p->p_flags2 & PF_CHANGED)
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STATIC bool match_pars(fm,act)
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formal_p fm;
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actual_p act;
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{
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/* Check if every actual parameter has the same
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* size as its corresponding formal. If not, the
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* actual parameters should not be expanded in line.
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*/
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while (act != (actual_p) 0) {
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if (fm == (formal_p) 0 || tsize(fm->f_type) != act->ac_size) {
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return FALSE;
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}
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act = act->ac_next;
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fm = fm->f_next;
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}
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return (fm == (formal_p) 0 ? TRUE : FALSE);
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}
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STATIC bool change_act(p,act)
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proc_p p;
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actual_p act;
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{
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/* See if a call to p migth change any of the
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* operands of the actual parameter expression.
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* If the parameter is to be expanded in line,
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* we must be sure its value does not depend
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* on the point in the program where it is
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* evaluated.
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*/
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line_p l;
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for (l = act->ac_exp; l != (line_p) 0; l = l->l_next) {
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switch(INSTR(l)) {
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case op_lil:
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case op_lof:
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case op_loi:
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case op_los:
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case op_ldf:
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return TRUE;
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/* assume worst case */
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case op_lol:
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case op_ldl:
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if (CHANGE_INDIR(p)) {
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return TRUE;
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}
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break;
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case op_loe:
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case op_lde:
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if (CHANGE_INDIR(p) || CHANGE_EXT(p)) {
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return TRUE;
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}
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break;
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}
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}
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return FALSE;
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}
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STATIC bool is_simple(expr)
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line_p expr;
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{
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/* See if expr is something simple, i.e. a constant or
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* a variable. So the expression must consist of
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* only one instruction.
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*/
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if (expr->l_next == (line_p) 0) {
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switch(INSTR(expr)) {
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case op_loc:
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case op_ldc:
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case op_lol:
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case op_ldl:
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case op_loe:
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case op_lde:
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return TRUE;
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}
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}
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return FALSE;
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}
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STATIC bool too_expensive(fm,act)
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formal_p fm;
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actual_p act;
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{
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/* If the formal parameter is used often and the
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* actual parameter is not something simple
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* (i.e. an expression, not a constant or variable)
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* it may be too expensive too expand the parameter
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* in line.
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*/
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return (OFTEN_USED(fm) && !is_simple(act->ac_exp));
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}
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bool anal_params(c)
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call_p c;
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{
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/* Determine which of the actual parameters of a
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* call may be expanded in line.
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*/
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proc_p p;
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actual_p act;
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formal_p form;
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int inlpars = 0;
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p = c->cl_proc; /* the called procedure */
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if (!match_pars(p->P_FORMALS, c->cl_actuals)) return FALSE;
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if (!INLINE_PARS(p)) {
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for (act = c->cl_actuals; act != (actual_p) 0;
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act = act->ac_next) {
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NOT_INLINE(act);
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}
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return TRUE; /* "# of inline pars." field in cl_flags remains 0 */
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}
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for (act = c->cl_actuals, form = p->P_FORMALS; act != (actual_p) 0;
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act = act->ac_next, form = form->f_next) {
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if (form->f_flags & FF_BAD ||
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change_act(p,act) || too_expensive(form,act)) {
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NOT_INLINE(act);
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} else {
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INLINE(act);
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inlpars++;
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}
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}
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if (inlpars > 15) inlpars = 15; /* We've only got 4 bits! */
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c->cl_flags |= inlpars; /* number of inline parameters */
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return TRUE;
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}
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STATIC short space_saved(c)
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call_p c;
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{
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/* When a call gets expanded in line, the total size of the
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* code usually gets incremented, because we have to
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* duplicate the text of the called routine. However, we save
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* ourselves a CAL instruction and possibly anASP instruction
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* (if the called procedure has parameters). Moreover, if we
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* can put some parameters in line, we don't have to push
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* their results on the stack before doing the call, so we
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* save some code here too. The routine estimates the amount of
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* code saved, expressed in number of EM instructions.
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*/
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return (1 + (c->cl_flags & CLF_INLPARS) + (c->cl_proc->p_nrformals>0));
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}
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STATIC short param_score(c)
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call_p c;
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{
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/* If a call has an inline parameter that is a constant,
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* chances are high that other optimization techniques
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* can do further optimizations, especially if the constant
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* happens to be "0". So the call gets extra points for this.
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*/
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register actual_p act;
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line_p l;
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short score = 0;
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for (act = c->cl_actuals; act != (actual_p) 0; act = act->ac_next) {
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if (act->ac_inl) {
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l = act->ac_exp;
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if (l->l_next == (line_p) 0 &&
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(INSTR(l) == op_loc || INSTR(l) == op_ldc)) {
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score += (off_set(l) == (offset) 0 ? 2 : 1);
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/* 0's count for two! */
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}
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}
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}
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return score;
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}
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assign_ratio(c)
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call_p c;
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{
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/* This routine is one of the most important ones
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* of the inline substitution phase. It assigns a number
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* (a 'ratio') to a call, indicating how desirable
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* it is to expand the call in line.
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* Currently, a very simplified straightforward heuristic
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* is used.
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*/
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short ll, loopfact, ratio;
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ll = c->cl_proc->P_SIZE - space_saved(c);
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if (ll <= 0) ll = 1;
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ratio = 1000 / ll;
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if (ratio == 0) ratio = 1;
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/* Add points if the called procedure falls through
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* it's end (no BRA needed) or has formal parameters
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* (ASP can be deleted).
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*/
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if (c->cl_proc->p_flags2 & PF_FALLTHROUGH) {
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ratio += 10;
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}
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if (c->cl_proc->p_nrformals > 0) {
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ratio += 10;
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}
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if (c->cl_caller->p_localbytes == 0) {
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ratio -= 10;
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}
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ratio += (10 *param_score(c));
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/* Extra points for constants as parameters */
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if (ratio <= 0) ratio = 1;
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ll = c->cl_looplevel+1;
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if (ll == 1 && !IS_CALLED_IN_LOOP(c->cl_caller)) ll = 0;
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/* If the call is not in a loop and the called proc. is never called
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* in a loop, ll is set to 0.
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*/
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loopfact = (ll > 3 ? 10 : ll*ll);
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ratio *= loopfact;
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if (c->cl_flags & CLF_FIRM) {
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ratio = 2*ratio;
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}
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c->cl_ratio = ratio;
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}
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call_p abstract(c)
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call_p c;
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{
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/* Abstract information from the call that is essential
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* for choosing the calls that will be expanded.
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* Put the information is an 'abstracted call'.
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*/
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call_p a;
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a = newcall();
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a->cl_caller = c->cl_caller;
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a->cl_id = c->cl_id;
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a->cl_proc = c->cl_proc;
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a->cl_looplevel = c->cl_looplevel;
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a->cl_ratio = c->cl_ratio;
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a->cl_flags = c->cl_flags;
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return a;
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}
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STATIC adjust_counts(callee,ccf)
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proc_p callee;
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FILE *ccf;
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{
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/* A call to callee is expanded in line;
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* the text of callee is not removed, so
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* every proc called by callee gets its
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* P_NRCALLED field incremented.
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*/
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calcnt_p cc, head;
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head = getcc(ccf,callee); /* get calcnt info of called proc */
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for (cc = head; cc != (calcnt_p) 0; cc = cc->cc_next) {
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cc->cc_proc->P_NRCALLED += cc->cc_count;
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}
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remcc(head); /* remove calcnt info */
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}
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STATIC bool is_dispensable(callee,ccf)
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proc_p callee;
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FILE *ccf;
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{
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/* A call to callee is expanded in line.
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* Decrement its P_NRCALLED field and see if
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* it can now be removed because it is no
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* longer called. Procedures that ever have
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* their address taken (via LPI) will never
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* be removed, as they might be called indirectly.
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*/
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if ((--callee->P_NRCALLED) == 0 &&
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(complete_program || (callee->p_flags1 & PF_EXTERNAL) == 0) &&
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(callee->p_flags1 & PF_LPI) == 0) {
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DISPENSABLE(callee);
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OUTVERBOSE("dispensable: procedure %d can be removed",callee->p_id);
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#ifdef VERBOSE
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Spremoved++;
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#endif
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return TRUE;
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} else {
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adjust_counts(callee,ccf);
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return FALSE;
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}
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}
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STATIC call_p nested_calls(a)
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call_p a;
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{
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/* Get a list of all calls that will appear in the
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* EM text if the call 'a' is expanded in line.
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* These are the calls in the P_CALS list of the
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* called procedure.
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*/
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call_p c, cp, head, *cpp;
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head = (call_p) 0;
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cpp = &head;
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for (c = a->cl_proc->P_CALS; c != (call_p) 0; c = c->cl_cdr) {
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cp = abstract(c);
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cp->cl_looplevel += a->cl_looplevel;
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cp->cl_flags = (byte) 0;
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if (a->cl_flags & CLF_FIRM) {
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cp->cl_flags |= CLF_FIRM;
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}
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assign_ratio(cp);
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*cpp = cp;
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cpp = &cp->cl_cdr;
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}
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return head;
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}
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STATIC call_p find_origin(c)
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call_p c;
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{
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/* c is a nested call. Find the original call.
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* This origional must be in the P_CALS list
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* of the calling procedure.
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*/
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register call_p x;
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for (x = c->cl_caller->P_CALS; x != (call_p) 0; x = x->cl_cdr) {
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if (x->cl_id == c->cl_id) return x;
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}
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assert(FALSE);
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/* NOTREACHED */
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}
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STATIC selected(a)
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call_p a;
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{
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/* The call a is selected for in line expansion.
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* Mark the call as being selected and get the
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* calls nested in it; these will be candidates
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* too now.
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*/
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SELECTED(a);
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EVER_EXPANDED(find_origin(a));
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a->cl_car = nested_calls(a);
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}
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STATIC compare(x,best,space)
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call_p x, *best;
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long space;
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{
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/* See if x is better than the current best choice */
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if (x != (call_p) 0 && !IS_CHANGED(x->cl_proc) &&
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x->cl_proc->P_SIZE - space_saved(x) <= space) {
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if ((*best == (call_p) 0 && x->cl_ratio != 0) ||
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(*best != (call_p) 0 && x->cl_ratio > (*best)->cl_ratio )) {
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*best = x;
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}
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}
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}
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STATIC call_p best_one(list,space)
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call_p list;
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long space;
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{
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/* Find the best candidate of the list
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* that has not already been selected. The
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* candidate must fit in the given space.
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* We look in the cdr as well as in the car
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* direction.
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*/
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call_p best = (call_p) 0;
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call_p c;
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for (c = list; c != (call_p) 0; c = c->cl_cdr) {
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if (IS_SELECTED(c)) {
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compare(best_one(c->cl_car,space),&best,space);
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} else {
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compare(c,&best,space);
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}
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}
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return best;
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}
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STATIC singles(cals)
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call_p cals;
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{
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/* If a procedure is only called once, this call
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* will be expanded in line, because it costs
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* no extra space.
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*/
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call_p c;
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for (c = cals; c != (call_p) 0; c = c->cl_cdr) {
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if (IS_SELECTED(c)) {
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singles(c->cl_car);
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} else {
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if (c->cl_proc->P_NRCALLED == 1 &&
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!IS_CHANGED(c->cl_proc) &&
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(complete_program ||
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(c->cl_proc->p_flags1 & PF_EXTERNAL) == 0) &&
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(c->cl_proc->p_flags1 & PF_LPI) == 0) {
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c->cl_proc->P_NRCALLED = 0;
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SELECTED(c);
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EVER_EXPANDED(find_origin(c));
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DISPENSABLE(c->cl_proc);
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CHANGED(c->cl_caller);
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OUTVERBOSE("singles: procedure %d can be removed",
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c->cl_proc->p_id);
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#ifdef VERBOSE
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Spremoved++;
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#endif
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}
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}
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}
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}
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STATIC single_calls(proclist)
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proc_p proclist;
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{
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proc_p p;
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for (p = proclist; p != (proc_p) 0; p = p->p_next) {
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if (!BIG_CALLER(p) && !IS_DISPENSABLE(p)) {
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/* Calls appearing in a large procedure or in
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* a procedure that was already eliminated
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* are not considered.
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*/
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singles(p->P_CALS);
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}
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}
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}
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select_calls(proclist,ccf,space)
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proc_p proclist;
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FILE *ccf;
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long space ;
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{
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/* Select all calls that are to be expanded in line. */
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proc_p p,chp;
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call_p best, x;
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for (;;) {
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best = (call_p) 0;
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chp = (proc_p) 0; /* the changed procedure */
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for (p = proclist; p != (proc_p) 0; p = p->p_next) {
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if (!BIG_CALLER(p) && !IS_DISPENSABLE(p)) {
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/* Calls appearing in a large procedure or in
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* a procedure that was already eliminated
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* are not considered.
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*/
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x = best_one(p->P_CALS,space);
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compare(x,&best,space);
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if (x == best) chp = p;
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}
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}
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if (best == (call_p) 0) break;
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if (!is_dispensable(best->cl_proc,ccf)) {
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space -= (best->cl_proc->P_SIZE - space_saved(best));
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}
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else space += space_saved(best);
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#ifdef VERBOSE
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if (verbose_flag) fprintf(stderr, "space left: %ld\n", space);
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#endif
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selected(best);
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CHANGED(chp);
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}
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single_calls(proclist);
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#ifdef VERBOSE
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Sstat(proclist,space);
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#endif
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}
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STATIC nonnested_calls(cfile)
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FILE *cfile;
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{
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register call_p c,a;
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while((c = getcall(cfile)) != (call_p) 0) {
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/* find the call in the call list of the caller */
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for (a = c->cl_caller->P_CALS;
|
|
a != (call_p) 0 && c->cl_id != a->cl_id; a = a->cl_cdr);
|
|
assert(a != (call_p) 0 && a->cl_proc == c->cl_proc);
|
|
if (IS_EVER_EXPANDED(a)) {
|
|
a->cl_actuals = c->cl_actuals;
|
|
c->cl_actuals = (actual_p) 0;
|
|
}
|
|
rem_call(c);
|
|
}
|
|
}
|
|
|
|
|
|
|
|
STATIC copy_pars(src,dest)
|
|
call_p src, dest;
|
|
{
|
|
/* Copy the actual parameters of src to dest. */
|
|
|
|
actual_p as,ad, *app;
|
|
|
|
app = &dest->cl_actuals;
|
|
for (as = src->cl_actuals; as != (actual_p) 0; as = as->ac_next) {
|
|
ad = newactual();
|
|
ad->ac_exp = copy_expr(as->ac_exp);
|
|
ad->ac_size = as->ac_size;
|
|
ad->ac_inl = as->ac_inl;
|
|
*app = ad;
|
|
app = &ad->ac_next;
|
|
}
|
|
}
|
|
|
|
|
|
|
|
STATIC nest_pars(cals)
|
|
call_p cals;
|
|
{
|
|
/* Recursive auxiliary procedure of add_actuals. */
|
|
|
|
call_p c,org;
|
|
|
|
for (c = cals; c != (call_p) 0; c = c->cl_cdr) {
|
|
if (IS_SELECTED(c)) {
|
|
org = find_origin(c);
|
|
copy_pars(org,c);
|
|
nest_pars(c->cl_car);
|
|
}
|
|
}
|
|
}
|
|
|
|
|
|
|
|
add_actuals(proclist,cfile)
|
|
proc_p proclist;
|
|
FILE *cfile;
|
|
{
|
|
/* Fetch the actual parameters of all selected calls.
|
|
* For all non-nested calls (i.e. those calls that
|
|
* appeared originally in the EM text), we get the
|
|
* parameters from the cal-file.
|
|
* For nested calls (i.e. calls
|
|
* that are a result of in line substitution) we
|
|
* get the parameters from the original call.
|
|
*/
|
|
|
|
proc_p p;
|
|
call_p a;
|
|
|
|
nonnested_calls(cfile);
|
|
for (p = proclist; p != (proc_p) 0; p = p->p_next) {
|
|
for (a = p->P_CALS; a != (call_p) 0; a = a->cl_cdr) {
|
|
nest_pars(a->cl_car);
|
|
}
|
|
}
|
|
}
|
|
|
|
|
|
|
|
STATIC clean(cals)
|
|
call_p *cals;
|
|
{
|
|
call_p c,next,*cpp;
|
|
|
|
/* Recursive auxiliary routine of cleancals */
|
|
|
|
cpp = cals;
|
|
for (c = *cpp; c != (call_p) 0; c = next) {
|
|
next = c->cl_cdr;
|
|
if (IS_SELECTED(c)) {
|
|
clean(&c->cl_car);
|
|
cpp = &c->cl_cdr;
|
|
} else {
|
|
assert(c->cl_car == (call_p) 0);
|
|
oldcall(c);
|
|
*cpp = next;
|
|
}
|
|
}
|
|
}
|
|
|
|
|
|
cleancals(proclist)
|
|
proc_p proclist;
|
|
{
|
|
/* Remove all calls in the P_CALS list of p
|
|
* that were not selected for in line expansion.
|
|
*/
|
|
|
|
register proc_p p;
|
|
|
|
for (p = proclist; p != (proc_p) 0; p = p->p_next) {
|
|
clean(&p->P_CALS);
|
|
}
|
|
}
|
|
|
|
|
|
|
|
|
|
append_abstract(a,p)
|
|
call_p a;
|
|
proc_p p;
|
|
{
|
|
/* Append an abstract of a call-descriptor to
|
|
* the call-list of procedure p.
|
|
*/
|
|
|
|
call_p c;
|
|
|
|
if (p->P_CALS == (call_p) 0) {
|
|
p->P_CALS = a;
|
|
} else {
|
|
for (c = p->P_CALS; c->cl_cdr != (call_p) 0; c = c->cl_cdr);
|
|
c->cl_cdr = a;
|
|
}
|
|
}
|
|
|
|
|
|
#ifdef VERBOSE
|
|
|
|
/* At the end, we traverse the entire call-list, to see why the
|
|
* remaining calls were not expanded inline.
|
|
*/
|
|
|
|
|
|
Sstatist(list,space)
|
|
call_p list;
|
|
long space;
|
|
{
|
|
call_p c;
|
|
|
|
for (c = list; c != (call_p) 0; c = c->cl_cdr) {
|
|
if (IS_SELECTED(c)) {
|
|
Sstatist(c->cl_car,space);
|
|
} else {
|
|
if (IS_CHANGED(c->cl_proc)) Schangedcallee++;
|
|
else if (BIG_PROC(c->cl_proc)) Sbigcallee++;
|
|
else if (c->cl_proc->P_SIZE > space) Sspace++;
|
|
else if (c->cl_ratio == 0) Szeroratio++;
|
|
else assert(FALSE);
|
|
}
|
|
}
|
|
}
|
|
|
|
Sstat(proclist,space)
|
|
proc_p proclist;
|
|
long space;
|
|
{
|
|
proc_p p;
|
|
|
|
for (p = proclist; p != (proc_p) 0; p = p->p_next) {
|
|
if (BIG_CALLER(p)) Sbig_caller++;
|
|
else if (IS_DISPENSABLE(p)) Sdispensable++;
|
|
else Sstatist(p->P_CALS,space);
|
|
}
|
|
}
|
|
#endif
|