Annotation of gforth/engine/peephole.c, revision 1.7

1.1       anton       1: /* Peephole optimization routines and tables
                      2: 
1.7     ! anton       3:   Copyright (C) 2001,2002 Free Software Foundation, Inc.
1.1       anton       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"
1.2       anton      24: #include <stdlib.h>
1.4       ak042      25: #include <string.h>
                     26: #include <assert.h>
1.1       anton      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: 
1.6       anton      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: 
1.3       anton      99: int use_super = 1;
                    100: 
                    101: typedef Xt Inst;
1.1       anton     102: 
1.3       anton     103: typedef struct Peeptable_entry {
                    104:   struct Peeptable_entry *next;
                    105:   Inst prefix;
                    106:   Inst lastprim;
                    107:   Inst combination_prim;
                    108: } Peeptable_entry;
1.1       anton     109: 
1.3       anton     110: #define HASH_SIZE 1024
                    111: #define hash(_i1,_i2) (((((Cell)(_i1))^((Cell)(_i2)))>>4)&(HASH_SIZE-1))
1.1       anton     112: 
1.3       anton     113: Cell peeptable;
1.1       anton     114: 
1.3       anton     115: Cell prepare_peephole_table(Inst insts[])
1.1       anton     116: {
                    117:   Cell i;
1.3       anton     118:   Peeptable_entry **pt = (Peeptable_entry **)calloc(HASH_SIZE,sizeof(Peeptable_entry *));
1.1       anton     119: 
1.3       anton     120:   for (i=0; i<sizeof(peephole_table)/sizeof(peephole_table[0]); i++) {
1.1       anton     121:     Combination *c = &peephole_table[i];
1.3       anton     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;
1.1       anton     130:   }
1.3       anton     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;
1.1       anton     145: }

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