/* Peephole optimization routines and tables Copyright (C) 2001,2002,2003 Free Software Foundation, Inc. This file is part of Gforth. Gforth is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 2 of the License, or (at your option) any later version. This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with this program; if not, write to the Free Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111, USA. */ #include #include "mini.h" /* the numbers in this struct are primitive indices */ typedef struct Combination { int prefix; int lastprim; int combination_prim; } Combination; Combination peephole_table[] = { #include "mini-peephole.i" #ifndef __GNUC__ {-1,-1,-1} /* unnecessary; just to shut up lcc if the file is empty */ #endif }; int use_super = 1; /* turned off by option -p */ typedef struct Peeptable_entry { struct Peeptable_entry *next; Inst prefix; Inst lastprim; Inst combination_prim; } Peeptable_entry; #define HASH_SIZE 1024 #define hash(_i1,_i2) (((((Cell)(_i1))^((Cell)(_i2)))>>4)&(HASH_SIZE-1)) Cell peeptable; Cell prepare_peephole_table(Inst insts[]) { Cell i; Peeptable_entry **pt = (Peeptable_entry **)calloc(HASH_SIZE,sizeof(Peeptable_entry *)); for (i=0; iprefix = insts[c->prefix]; p->lastprim = insts[c->lastprim]; p->combination_prim = insts[c->combination_prim]; h = hash(p->prefix,p->lastprim); p->next = pt[h]; pt[h] = p; } return (Cell)pt; } void init_peeptable(void) { peeptable = prepare_peephole_table(vm_prim); } Inst peephole_opt(Inst inst1, Inst inst2, Cell peeptable) { Peeptable_entry **pt = (Peeptable_entry **)peeptable; Peeptable_entry *p; if (use_super == 0) return 0; for (p = pt[hash(inst1,inst2)]; p != NULL; p = p->next) if (inst1 == p->prefix && inst2 == p->lastprim) return p->combination_prim; return NULL; } Inst *last_compiled = NULL; void gen_inst(Inst **vmcodepp, Inst i) { if (last_compiled != NULL) { Inst combo = peephole_opt(*last_compiled, i, peeptable); if (combo != NULL) { *last_compiled = combo; return; } } last_compiled = *vmcodepp; **vmcodepp = i; (*vmcodepp)++; }