File:  [gforth] / gforth / engine / peephole.c
Revision 1.8: download - view: text, annotated - select for diffs
Mon Aug 25 14:17:52 2003 UTC (18 years, 3 months ago) by anton
Branches: MAIN
CVS tags: v0-6-2, HEAD
documentation updates
fixed some portability bugs in vmgen-ex and vmgen-ex2
updated copyright years

    1: /* Peephole optimization routines and tables
    2: 
    3:   Copyright (C) 2001,2002,2003 Free Software Foundation, Inc.
    4: 
    5:   This file is part of Gforth.
    6: 
    7:   Gforth is free software; you can redistribute it and/or
    8:   modify it under the terms of the GNU General Public License
    9:   as published by the Free Software Foundation; either version 2
   10:   of the License, or (at your option) any later version.
   11: 
   12:   This program is distributed in the hope that it will be useful,
   13:   but WITHOUT ANY WARRANTY; without even the implied warranty of
   14:   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   15:   GNU General Public License for more details.
   16: 
   17:   You should have received a copy of the GNU General Public License
   18:   along with this program; if not, write to the Free Software
   19:   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111, USA.
   20: */
   21: 
   22: #include "config.h"
   23: #include "forth.h"
   24: #include <stdlib.h>
   25: #include <string.h>
   26: #include <assert.h>
   27: 
   28: /* the numbers in this struct are primitive indices */
   29: typedef struct Combination {
   30:   int prefix;
   31:   int lastprim;
   32:   int combination_prim;
   33: } Combination;
   34: 
   35: Combination peephole_table[] = {
   36: #include "peephole.i"
   37: };
   38: 
   39: #ifdef PRINT_SUPER_LENGTHS
   40: char *prim_names[] = {
   41: #include "prim_names.i"
   42: };
   43: 
   44: Combination *find_super(Cell prim)
   45: {
   46:   Cell i;
   47: 
   48:   for (i=0; i<sizeof(peephole_table)/sizeof(peephole_table[0]); i++) {
   49:     if (peephole_table[i].combination_prim == prim)
   50:       return &peephole_table[i];
   51:   }
   52:   return NULL;
   53: }
   54: 
   55: Cell sum_length(Cell prim)
   56: {
   57:   Combination *super=find_super(prim);
   58: 
   59:   if (super)
   60:     return sum_length(super->prefix)+prim_length(super->lastprim);
   61:   else
   62:     return prim_length(prim);
   63: }
   64: 
   65: void print_prim(Cell prim)
   66: {
   67:   fprintf(stderr, "%s", prim_names[prim]);
   68: }  
   69: 
   70: void print_super(Cell prim)
   71: {
   72:   Combination *super=find_super(prim);
   73:   
   74:   if (super) {
   75:     print_super(super->prefix);
   76:     fprintf(stderr, " ");
   77:     print_prim(super->lastprim);
   78:   } else {
   79:     print_prim(prim);
   80:   }
   81: }
   82: 
   83: void print_super_lengths()
   84: {
   85:   Cell i;
   86: 
   87:   for (i=0; i<sizeof(peephole_table)/sizeof(peephole_table[0]); i++) {
   88:     Cell super_length = prim_length(peephole_table[i].combination_prim);
   89:     Cell sum_super_length = sum_length(peephole_table[i].combination_prim);
   90: 
   91:     fprintf(stderr, "%6.4f %3d %3d ", ((double)super_length)/sum_super_length,
   92: 	    super_length, sum_super_length);
   93:     print_super(peephole_table[i].combination_prim);
   94:     fprintf(stderr,"\n");
   95:   }
   96: }
   97: #endif
   98: 
   99: int use_super = 1;
  100: 
  101: typedef Xt Inst;
  102: 
  103: typedef struct Peeptable_entry {
  104:   struct Peeptable_entry *next;
  105:   Inst prefix;
  106:   Inst lastprim;
  107:   Inst combination_prim;
  108: } Peeptable_entry;
  109: 
  110: #define HASH_SIZE 1024
  111: #define hash(_i1,_i2) (((((Cell)(_i1))^((Cell)(_i2)))>>4)&(HASH_SIZE-1))
  112: 
  113: Cell peeptable;
  114: 
  115: Cell prepare_peephole_table(Inst insts[])
  116: {
  117:   Cell i;
  118:   Peeptable_entry **pt = (Peeptable_entry **)calloc(HASH_SIZE,sizeof(Peeptable_entry *));
  119: 
  120:   for (i=0; i<sizeof(peephole_table)/sizeof(peephole_table[0]); i++) {
  121:     Combination *c = &peephole_table[i];
  122:     Peeptable_entry *p = (Peeptable_entry *)malloc(sizeof(Peeptable_entry));
  123:     Cell h;
  124:     p->prefix =           insts[c->prefix];
  125:     p->lastprim =         insts[c->lastprim];
  126:     p->combination_prim = insts[c->combination_prim];
  127:     h = hash(p->prefix,p->lastprim);
  128:     p->next = pt[h];
  129:     pt[h] = p;
  130:   }
  131:   return (Cell)pt;
  132: }
  133: 
  134: Inst peephole_opt(Inst inst1, Inst inst2, Cell peeptable)
  135: {
  136:   Peeptable_entry **pt = (Peeptable_entry **)peeptable;
  137:   Peeptable_entry *p;
  138: 
  139:   if (use_super == 0)
  140:       return 0;
  141:   for (p = pt[hash(inst1,inst2)]; p != NULL; p = p->next)
  142:     if (inst1 == p->prefix && inst2 == p->lastprim)
  143:       return p->combination_prim;
  144:   return NULL;
  145: }

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