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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