1: /* Peephole optimization routines and tables
2:
3: Copyright (C) 2001,2002,2003,2007 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 3
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, see http://www.gnu.org/licenses/.
19: */
20:
21: #include "config.h"
22: #include "forth.h"
23: #include <stdlib.h>
24: #include <string.h>
25: #include <assert.h>
26:
27: /* the numbers in this struct are primitive indices */
28: typedef struct Combination {
29: int prefix;
30: int lastprim;
31: int combination_prim;
32: } Combination;
33:
34: Combination peephole_table[] = {
35: #include PEEPHOLE_I
36: };
37:
38: #ifdef PRINT_SUPER_LENGTHS
39: char *prim_names[] = {
40: #include PRIM_NAMES_I
41: };
42:
43: Combination *find_super(Cell prim)
44: {
45: Cell i;
46:
47: for (i=0; i<sizeof(peephole_table)/sizeof(peephole_table[0]); i++) {
48: if (peephole_table[i].combination_prim == prim)
49: return &peephole_table[i];
50: }
51: return NULL;
52: }
53:
54: Cell sum_length(Cell prim)
55: {
56: Combination *super=find_super(prim);
57:
58: if (super)
59: return sum_length(super->prefix)+prim_length(super->lastprim);
60: else
61: return prim_length(prim);
62: }
63:
64: void print_prim(Cell prim)
65: {
66: fprintf(stderr, "%s", prim_names[prim]);
67: }
68:
69: void print_super(Cell prim)
70: {
71: Combination *super=find_super(prim);
72:
73: if (super) {
74: print_super(super->prefix);
75: fprintf(stderr, " ");
76: print_prim(super->lastprim);
77: } else {
78: print_prim(prim);
79: }
80: }
81:
82: void print_super_lengths()
83: {
84: Cell i;
85:
86: for (i=0; i<sizeof(peephole_table)/sizeof(peephole_table[0]); i++) {
87: Cell super_length = prim_length(peephole_table[i].combination_prim);
88: Cell sum_super_length = sum_length(peephole_table[i].combination_prim);
89:
90: fprintf(stderr, "%6.4f %3d %3d ", ((double)super_length)/sum_super_length,
91: super_length, sum_super_length);
92: print_super(peephole_table[i].combination_prim);
93: fprintf(stderr,"\n");
94: }
95: }
96: #endif
97:
98: int use_super = 1;
99:
100: typedef Xt Inst;
101:
102: typedef struct Peeptable_entry {
103: struct Peeptable_entry *next;
104: Inst prefix;
105: Inst lastprim;
106: Inst combination_prim;
107: } Peeptable_entry;
108:
109: #define HASH_SIZE 1024
110: #define hash(_i1,_i2) (((((Cell)(_i1))^((Cell)(_i2)))>>4)&(HASH_SIZE-1))
111:
112: Cell peeptable;
113:
114: Cell prepare_peephole_table(Inst insts[])
115: {
116: Cell i;
117: Peeptable_entry **pt = (Peeptable_entry **)calloc(HASH_SIZE,sizeof(Peeptable_entry *));
118:
119: for (i=0; i<sizeof(peephole_table)/sizeof(peephole_table[0]); i++) {
120: Combination *c = &peephole_table[i];
121: Peeptable_entry *p = (Peeptable_entry *)malloc(sizeof(Peeptable_entry));
122: Cell h;
123: p->prefix = insts[c->prefix];
124: p->lastprim = insts[c->lastprim];
125: p->combination_prim = insts[c->combination_prim];
126: h = hash(p->prefix,p->lastprim);
127: p->next = pt[h];
128: pt[h] = p;
129: }
130: return (Cell)pt;
131: }
132:
133: Inst peephole_opt(Inst inst1, Inst inst2, Cell peeptable)
134: {
135: Peeptable_entry **pt = (Peeptable_entry **)peeptable;
136: Peeptable_entry *p;
137:
138: if (use_super == 0)
139: return 0;
140: for (p = pt[hash(inst1,inst2)]; p != NULL; p = p->next)
141: if (inst1 == p->prefix && inst2 == p->lastprim)
142: return p->combination_prim;
143: return NULL;
144: }
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