-/*
- * Copyright (c) 1999 Apple Computer, Inc. All rights reserved.
- *
- * @APPLE_LICENSE_HEADER_START@
- *
- * "Portions Copyright (c) 1999 Apple Computer, Inc. All Rights
- * Reserved. This file contains Original Code and/or Modifications of
- * Original Code as defined in and that are subject to the Apple Public
- * Source License Version 1.0 (the 'License'). You may not use this file
- * except in compliance with the License. Please obtain a copy of the
- * License at http://www.apple.com/publicsource and read it before using
- * this file.
- *
- * The Original Code and all software distributed under the License are
- * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
- * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
- * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
- * FITNESS FOR A PARTICULAR PURPOSE OR NON-INFRINGEMENT. Please see the
- * License for the specific language governing rights and limitations
- * under the License."
- *
- * @APPLE_LICENSE_HEADER_END@
- */
-/* $OpenBSD: optimize.c,v 1.5 1996/09/16 02:33:07 tholo Exp $ */
-
-/*
- * Copyright (c) 1988, 1989, 1990, 1991, 1993, 1994, 1995, 1996
- * The Regents of the University of California. All rights reserved.
- *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that: (1) source code distributions
- * retain the above copyright notice and this paragraph in its entirety, (2)
- * distributions including binary code include the above copyright notice and
- * this paragraph in its entirety in the documentation or other materials
- * provided with the distribution, and (3) all advertising materials mentioning
- * features or use of this software display the following acknowledgement:
- * ``This product includes software developed by the University of California,
- * Lawrence Berkeley Laboratory and its contributors.'' Neither the name of
- * the University nor the names of its contributors may be used to endorse
- * or promote products derived from this software without specific prior
- * written permission.
- * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR IMPLIED
- * WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF
- * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
- *
- * Optimization module for tcpdump intermediate representation.
- */
-#ifndef lint
-static char rcsid[] =
- "@(#) Header: optimize.c,v 1.58 96/06/16 22:36:59 leres Exp (LBL)";
-#endif
-
-#include <sys/types.h>
-#include <sys/time.h>
-
-#include <net/bpf.h>
-
-#include <stdio.h>
-#include <stdlib.h>
-#include <memory.h>
-
-#ifdef HAVE_OS_PROTO_H
-#include "os-proto.h"
-#endif
-
-#include "pcap-int.h"
-#include "gencode.h"
-
-#ifdef BDEBUG
-extern int dflag;
-#endif
-
-#define A_ATOM BPF_MEMWORDS
-#define X_ATOM (BPF_MEMWORDS+1)
-
-#define NOP -1
-
-/*
- * This define is used to represent *both* the accumulator and
- * x register in use-def computations.
- * Currently, the use-def code assumes only one definition per instruction.
- */
-#define AX_ATOM N_ATOMS
-
-/*
- * A flag to indicate that further optimization is needed.
- * Iterative passes are continued until a given pass yields no
- * branch movement.
- */
-static int done;
-
-/*
- * A block is marked if only if its mark equals the current mark.
- * Rather than traverse the code array, marking each item, 'cur_mark' is
- * incremented. This automatically makes each element unmarked.
- */
-static int cur_mark;
-#define isMarked(p) ((p)->mark == cur_mark)
-#define unMarkAll() cur_mark += 1
-#define Mark(p) ((p)->mark = cur_mark)
-
-static void opt_init(struct block *);
-static void opt_cleanup(void);
-
-static void make_marks(struct block *);
-static void mark_code(struct block *);
-
-static void intern_blocks(struct block *);
-
-static int eq_slist(struct slist *, struct slist *);
-
-static void find_levels_r(struct block *);
-
-static void find_levels(struct block *);
-static void find_dom(struct block *);
-static void propedom(struct edge *);
-static void find_edom(struct block *);
-static void find_closure(struct block *);
-static int atomuse(struct stmt *);
-static int atomdef(struct stmt *);
-static void compute_local_ud(struct block *);
-static void find_ud(struct block *);
-static void init_val(void);
-static int F(int, int, int);
-static __inline void vstore(struct stmt *, int *, int, int);
-static void opt_blk(struct block *, int);
-static int use_conflict(struct block *, struct block *);
-static void opt_j(struct edge *);
-static void or_pullup(struct block *);
-static void and_pullup(struct block *);
-static void opt_blks(struct block *, int);
-static __inline void link_inedge(struct edge *, struct block *);
-static void find_inedges(struct block *);
-static void opt_root(struct block **);
-static void opt_loop(struct block *, int);
-static void fold_op(struct stmt *, int, int);
-static __inline struct slist *this_op(struct slist *);
-static void opt_not(struct block *);
-static void opt_peep(struct block *);
-static void opt_stmt(struct stmt *, int[], int);
-static void deadstmt(struct stmt *, struct stmt *[]);
-static void opt_deadstores(struct block *);
-static void opt_blk(struct block *, int);
-static int use_conflict(struct block *, struct block *);
-static void opt_j(struct edge *);
-static struct block *fold_edge(struct block *, struct edge *);
-static __inline int eq_blk(struct block *, struct block *);
-static int slength(struct slist *);
-static int count_blocks(struct block *);
-static void number_blks_r(struct block *);
-static int count_stmts(struct block *);
-static int convert_code_r(struct block *);
-#ifdef BDEBUG
-static void opt_dump(struct block *);
-#endif
-
-static int n_blocks;
-struct block **blocks;
-static int n_edges;
-struct edge **edges;
-
-/*
- * A bit vector set representation of the dominators.
- * We round up the set size to the next power of two.
- */
-static int nodewords;
-static int edgewords;
-struct block **levels;
-bpf_u_int32 *space;
-#define BITS_PER_WORD (8*sizeof(bpf_u_int32))
-/*
- * True if a is in uset {p}
- */
-#define SET_MEMBER(p, a) \
-((p)[(unsigned)(a) / BITS_PER_WORD] & (1 << ((unsigned)(a) % BITS_PER_WORD)))
-
-/*
- * Add 'a' to uset p.
- */
-#define SET_INSERT(p, a) \
-(p)[(unsigned)(a) / BITS_PER_WORD] |= (1 << ((unsigned)(a) % BITS_PER_WORD))
-
-/*
- * Delete 'a' from uset p.
- */
-#define SET_DELETE(p, a) \
-(p)[(unsigned)(a) / BITS_PER_WORD] &= ~(1 << ((unsigned)(a) % BITS_PER_WORD))
-
-/*
- * a := a intersect b
- */
-#define SET_INTERSECT(a, b, n)\
-{\
- register bpf_u_int32 *_x = a, *_y = b;\
- register int _n = n;\
- while (--_n >= 0) *_x++ &= *_y++;\
-}
-
-/*
- * a := a - b
- */
-#define SET_SUBTRACT(a, b, n)\
-{\
- register bpf_u_int32 *_x = a, *_y = b;\
- register int _n = n;\
- while (--_n >= 0) *_x++ &=~ *_y++;\
-}
-
-/*
- * a := a union b
- */
-#define SET_UNION(a, b, n)\
-{\
- register bpf_u_int32 *_x = a, *_y = b;\
- register int _n = n;\
- while (--_n >= 0) *_x++ |= *_y++;\
-}
-
-static uset all_dom_sets;
-static uset all_closure_sets;
-static uset all_edge_sets;
-
-#ifndef MAX
-#define MAX(a,b) ((a)>(b)?(a):(b))
-#endif
-
-static void
-find_levels_r(b)
- struct block *b;
-{
- int level;
-
- if (isMarked(b))
- return;
-
- Mark(b);
- b->link = 0;
-
- if (JT(b)) {
- find_levels_r(JT(b));
- find_levels_r(JF(b));
- level = MAX(JT(b)->level, JF(b)->level) + 1;
- } else
- level = 0;
- b->level = level;
- b->link = levels[level];
- levels[level] = b;
-}
-
-/*
- * Level graph. The levels go from 0 at the leaves to
- * N_LEVELS at the root. The levels[] array points to the
- * first node of the level list, whose elements are linked
- * with the 'link' field of the struct block.
- */
-static void
-find_levels(root)
- struct block *root;
-{
- memset((char *)levels, 0, n_blocks * sizeof(*levels));
- unMarkAll();
- find_levels_r(root);
-}
-
-/*
- * Find dominator relationships.
- * Assumes graph has been leveled.
- */
-static void
-find_dom(root)
- struct block *root;
-{
- int i;
- struct block *b;
- bpf_u_int32 *x;
-
- /*
- * Initialize sets to contain all nodes.
- */
- x = all_dom_sets;
- i = n_blocks * nodewords;
- while (--i >= 0)
- *x++ = ~0;
- /* Root starts off empty. */
- for (i = nodewords; --i >= 0;)
- root->dom[i] = 0;
-
- /* root->level is the highest level no found. */
- for (i = root->level; i >= 0; --i) {
- for (b = levels[i]; b; b = b->link) {
- SET_INSERT(b->dom, b->id);
- if (JT(b) == 0)
- continue;
- SET_INTERSECT(JT(b)->dom, b->dom, nodewords);
- SET_INTERSECT(JF(b)->dom, b->dom, nodewords);
- }
- }
-}
-
-static void
-propedom(ep)
- struct edge *ep;
-{
- SET_INSERT(ep->edom, ep->id);
- if (ep->succ) {
- SET_INTERSECT(ep->succ->et.edom, ep->edom, edgewords);
- SET_INTERSECT(ep->succ->ef.edom, ep->edom, edgewords);
- }
-}
-
-/*
- * Compute edge dominators.
- * Assumes graph has been leveled and predecessors established.
- */
-static void
-find_edom(root)
- struct block *root;
-{
- int i;
- uset x;
- struct block *b;
-
- x = all_edge_sets;
- for (i = n_edges * edgewords; --i >= 0; )
- x[i] = ~0;
-
- /* root->level is the highest level no found. */
- memset(root->et.edom, 0, edgewords * sizeof(*(uset)0));
- memset(root->ef.edom, 0, edgewords * sizeof(*(uset)0));
- for (i = root->level; i >= 0; --i) {
- for (b = levels[i]; b != 0; b = b->link) {
- propedom(&b->et);
- propedom(&b->ef);
- }
- }
-}
-
-/*
- * Find the backwards transitive closure of the flow graph. These sets
- * are backwards in the sense that we find the set of nodes that reach
- * a given node, not the set of nodes that can be reached by a node.
- *
- * Assumes graph has been leveled.
- */
-static void
-find_closure(root)
- struct block *root;
-{
- int i;
- struct block *b;
-
- /*
- * Initialize sets to contain no nodes.
- */
- memset((char *)all_closure_sets, 0,
- n_blocks * nodewords * sizeof(*all_closure_sets));
-
- /* root->level is the highest level no found. */
- for (i = root->level; i >= 0; --i) {
- for (b = levels[i]; b; b = b->link) {
- SET_INSERT(b->closure, b->id);
- if (JT(b) == 0)
- continue;
- SET_UNION(JT(b)->closure, b->closure, nodewords);
- SET_UNION(JF(b)->closure, b->closure, nodewords);
- }
- }
-}
-
-/*
- * Return the register number that is used by s. If A and X are both
- * used, return AX_ATOM. If no register is used, return -1.
- *
- * The implementation should probably change to an array access.
- */
-static int
-atomuse(s)
- struct stmt *s;
-{
- register int c = s->code;
-
- if (c == NOP)
- return -1;
-
- switch (BPF_CLASS(c)) {
-
- case BPF_RET:
- return (BPF_RVAL(c) == BPF_A) ? A_ATOM :
- (BPF_RVAL(c) == BPF_X) ? X_ATOM : -1;
-
- case BPF_LD:
- case BPF_LDX:
- return (BPF_MODE(c) == BPF_IND) ? X_ATOM :
- (BPF_MODE(c) == BPF_MEM) ? s->k : -1;
-
- case BPF_ST:
- return A_ATOM;
-
- case BPF_STX:
- return X_ATOM;
-
- case BPF_JMP:
- case BPF_ALU:
- if (BPF_SRC(c) == BPF_X)
- return AX_ATOM;
- return A_ATOM;
-
- case BPF_MISC:
- return BPF_MISCOP(c) == BPF_TXA ? X_ATOM : A_ATOM;
- }
- abort();
- /* NOTREACHED */
-}
-
-/*
- * Return the register number that is defined by 's'. We assume that
- * a single stmt cannot define more than one register. If no register
- * is defined, return -1.
- *
- * The implementation should probably change to an array access.
- */
-static int
-atomdef(s)
- struct stmt *s;
-{
- if (s->code == NOP)
- return -1;
-
- switch (BPF_CLASS(s->code)) {
-
- case BPF_LD:
- case BPF_ALU:
- return A_ATOM;
-
- case BPF_LDX:
- return X_ATOM;
-
- case BPF_ST:
- case BPF_STX:
- return s->k;
-
- case BPF_MISC:
- return BPF_MISCOP(s->code) == BPF_TAX ? X_ATOM : A_ATOM;
- }
- return -1;
-}
-
-static void
-compute_local_ud(b)
- struct block *b;
-{
- struct slist *s;
- atomset def = 0, use = 0, kill = 0;
- int atom;
-
- for (s = b->stmts; s; s = s->next) {
- if (s->s.code == NOP)
- continue;
- atom = atomuse(&s->s);
- if (atom >= 0) {
- if (atom == AX_ATOM) {
- if (!ATOMELEM(def, X_ATOM))
- use |= ATOMMASK(X_ATOM);
- if (!ATOMELEM(def, A_ATOM))
- use |= ATOMMASK(A_ATOM);
- }
- else if (atom < N_ATOMS) {
- if (!ATOMELEM(def, atom))
- use |= ATOMMASK(atom);
- }
- else
- abort();
- }
- atom = atomdef(&s->s);
- if (atom >= 0) {
- if (!ATOMELEM(use, atom))
- kill |= ATOMMASK(atom);
- def |= ATOMMASK(atom);
- }
- }
- if (!ATOMELEM(def, A_ATOM) && BPF_CLASS(b->s.code) == BPF_JMP)
- use |= ATOMMASK(A_ATOM);
-
- b->def = def;
- b->kill = kill;
- b->in_use = use;
-}
-
-/*
- * Assume graph is already leveled.
- */
-static void
-find_ud(root)
- struct block *root;
-{
- int i, maxlevel;
- struct block *p;
-
- /*
- * root->level is the highest level no found;
- * count down from there.
- */
- maxlevel = root->level;
- for (i = maxlevel; i >= 0; --i)
- for (p = levels[i]; p; p = p->link) {
- compute_local_ud(p);
- p->out_use = 0;
- }
-
- for (i = 1; i <= maxlevel; ++i) {
- for (p = levels[i]; p; p = p->link) {
- p->out_use |= JT(p)->in_use | JF(p)->in_use;
- p->in_use |= p->out_use &~ p->kill;
- }
- }
-}
-
-/*
- * These data structures are used in a Cocke and Shwarz style
- * value numbering scheme. Since the flowgraph is acyclic,
- * exit values can be propagated from a node's predecessors
- * provided it is uniquely defined.
- */
-struct valnode {
- int code;
- int v0, v1;
- int val;
- struct valnode *next;
-};
-
-#define MODULUS 213
-static struct valnode *hashtbl[MODULUS];
-static int curval;
-static int maxval;
-
-/* Integer constants mapped with the load immediate opcode. */
-#define K(i) F(BPF_LD|BPF_IMM|BPF_W, i, 0L)
-
-struct vmapinfo {
- int is_const;
- bpf_int32 const_val;
-};
-
-struct vmapinfo *vmap;
-struct valnode *vnode_base;
-struct valnode *next_vnode;
-
-static void
-init_val()
-{
- curval = 0;
- next_vnode = vnode_base;
- memset((char *)vmap, 0, maxval * sizeof(*vmap));
- memset((char *)hashtbl, 0, sizeof hashtbl);
-}
-
-/* Because we really don't have an IR, this stuff is a little messy. */
-static int
-F(code, v0, v1)
- int code;
- int v0, v1;
-{
- u_int hash;
- int val;
- struct valnode *p;
-
- hash = (u_int)code ^ (v0 << 4) ^ (v1 << 8);
- hash %= MODULUS;
-
- for (p = hashtbl[hash]; p; p = p->next)
- if (p->code == code && p->v0 == v0 && p->v1 == v1)
- return p->val;
-
- val = ++curval;
- if (BPF_MODE(code) == BPF_IMM &&
- (BPF_CLASS(code) == BPF_LD || BPF_CLASS(code) == BPF_LDX)) {
- vmap[val].const_val = v0;
- vmap[val].is_const = 1;
- }
- p = next_vnode++;
- p->val = val;
- p->code = code;
- p->v0 = v0;
- p->v1 = v1;
- p->next = hashtbl[hash];
- hashtbl[hash] = p;
-
- return val;
-}
-
-static __inline void
-vstore(s, valp, newval, alter)
- struct stmt *s;
- int *valp;
- int newval;
- int alter;
-{
- if (alter && *valp == newval)
- s->code = NOP;
- else
- *valp = newval;
-}
-
-static void
-fold_op(s, v0, v1)
- struct stmt *s;
- int v0, v1;
-{
- bpf_int32 a, b;
-
- a = vmap[v0].const_val;
- b = vmap[v1].const_val;
-
- switch (BPF_OP(s->code)) {
- case BPF_ADD:
- a += b;
- break;
-
- case BPF_SUB:
- a -= b;
- break;
-
- case BPF_MUL:
- a *= b;
- break;
-
- case BPF_DIV:
- if (b == 0)
- bpf_error("division by zero");
- a /= b;
- break;
-
- case BPF_AND:
- a &= b;
- break;
-
- case BPF_OR:
- a |= b;
- break;
-
- case BPF_LSH:
- a <<= b;
- break;
-
- case BPF_RSH:
- a >>= b;
- break;
-
- case BPF_NEG:
- a = -a;
- break;
-
- default:
- abort();
- }
- s->k = a;
- s->code = BPF_LD|BPF_IMM;
- done = 0;
-}
-
-static __inline struct slist *
-this_op(s)
- struct slist *s;
-{
- while (s != 0 && s->s.code == NOP)
- s = s->next;
- return s;
-}
-
-static void
-opt_not(b)
- struct block *b;
-{
- struct block *tmp = JT(b);
-
- JT(b) = JF(b);
- JF(b) = tmp;
-}
-
-static void
-opt_peep(b)
- struct block *b;
-{
- struct slist *s;
- struct slist *next, *last;
- int val;
-
- s = b->stmts;
- if (s == 0)
- return;
-
- last = s;
- while (1) {
- s = this_op(s);
- if (s == 0)
- break;
- next = this_op(s->next);
- if (next == 0)
- break;
- last = next;
-
- /*
- * st M[k] --> st M[k]
- * ldx M[k] tax
- */
- if (s->s.code == BPF_ST &&
- next->s.code == (BPF_LDX|BPF_MEM) &&
- s->s.k == next->s.k) {
- done = 0;
- next->s.code = BPF_MISC|BPF_TAX;
- }
- /*
- * ld #k --> ldx #k
- * tax txa
- */
- if (s->s.code == (BPF_LD|BPF_IMM) &&
- next->s.code == (BPF_MISC|BPF_TAX)) {
- s->s.code = BPF_LDX|BPF_IMM;
- next->s.code = BPF_MISC|BPF_TXA;
- done = 0;
- }
- /*
- * This is an ugly special case, but it happens
- * when you say tcp[k] or udp[k] where k is a constant.
- */
- if (s->s.code == (BPF_LD|BPF_IMM)) {
- struct slist *add, *tax, *ild;
-
- /*
- * Check that X isn't used on exit from this
- * block (which the optimizer might cause).
- * We know the code generator won't generate
- * any local dependencies.
- */
- if (ATOMELEM(b->out_use, X_ATOM))
- break;
-
- if (next->s.code != (BPF_LDX|BPF_MSH|BPF_B))
- add = next;
- else
- add = this_op(next->next);
- if (add == 0 || add->s.code != (BPF_ALU|BPF_ADD|BPF_X))
- break;
-
- tax = this_op(add->next);
- if (tax == 0 || tax->s.code != (BPF_MISC|BPF_TAX))
- break;
-
- ild = this_op(tax->next);
- if (ild == 0 || BPF_CLASS(ild->s.code) != BPF_LD ||
- BPF_MODE(ild->s.code) != BPF_IND)
- break;
- /*
- * XXX We need to check that X is not
- * subsequently used. We know we can eliminate the
- * accumulator modifications since it is defined
- * by the last stmt of this sequence.
- *
- * We want to turn this sequence:
- *
- * (004) ldi #0x2 {s}
- * (005) ldxms [14] {next} -- optional
- * (006) addx {add}
- * (007) tax {tax}
- * (008) ild [x+0] {ild}
- *
- * into this sequence:
- *
- * (004) nop
- * (005) ldxms [14]
- * (006) nop
- * (007) nop
- * (008) ild [x+2]
- *
- */
- ild->s.k += s->s.k;
- s->s.code = NOP;
- add->s.code = NOP;
- tax->s.code = NOP;
- done = 0;
- }
- s = next;
- }
- /*
- * If we have a subtract to do a comparison, and the X register
- * is a known constant, we can merge this value into the
- * comparison.
- */
- if (last->s.code == (BPF_ALU|BPF_SUB|BPF_X) &&
- !ATOMELEM(b->out_use, A_ATOM)) {
- val = b->val[X_ATOM];
- if (vmap[val].is_const) {
- int op;
-
- b->s.k += vmap[val].const_val;
- op = BPF_OP(b->s.code);
- if (op == BPF_JGT || op == BPF_JGE) {
- struct block *t = JT(b);
- JT(b) = JF(b);
- JF(b) = t;
- b->s.k += 0x80000000;
- }
- last->s.code = NOP;
- done = 0;
- } else if (b->s.k == 0) {
- /*
- * sub x -> nop
- * j #0 j x
- */
- last->s.code = NOP;
- b->s.code = BPF_CLASS(b->s.code) | BPF_OP(b->s.code) |
- BPF_X;
- done = 0;
- }
- }
- /*
- * Likewise, a constant subtract can be simplified.
- */
- else if (last->s.code == (BPF_ALU|BPF_SUB|BPF_K) &&
- !ATOMELEM(b->out_use, A_ATOM)) {
- int op;
-
- b->s.k += last->s.k;
- last->s.code = NOP;
- op = BPF_OP(b->s.code);
- if (op == BPF_JGT || op == BPF_JGE) {
- struct block *t = JT(b);
- JT(b) = JF(b);
- JF(b) = t;
- b->s.k += 0x80000000;
- }
- done = 0;
- }
- /*
- * and #k nop
- * jeq #0 -> jset #k
- */
- if (last->s.code == (BPF_ALU|BPF_AND|BPF_K) &&
- !ATOMELEM(b->out_use, A_ATOM) && b->s.k == 0) {
- b->s.k = last->s.k;
- b->s.code = BPF_JMP|BPF_K|BPF_JSET;
- last->s.code = NOP;
- done = 0;
- opt_not(b);
- }
- /*
- * If the accumulator is a known constant, we can compute the
- * comparison result.
- */
- val = b->val[A_ATOM];
- if (vmap[val].is_const && BPF_SRC(b->s.code) == BPF_K) {
- bpf_int32 v = vmap[val].const_val;
- switch (BPF_OP(b->s.code)) {
-
- case BPF_JEQ:
- v = v == b->s.k;
- break;
-
- case BPF_JGT:
- v = (unsigned)v > b->s.k;
- break;
-
- case BPF_JGE:
- v = (unsigned)v >= b->s.k;
- break;
-
- case BPF_JSET:
- v &= b->s.k;
- break;
-
- default:
- abort();
- }
- if (JF(b) != JT(b))
- done = 0;
- if (v)
- JF(b) = JT(b);
- else
- JT(b) = JF(b);
- }
-}
-
-/*
- * Compute the symbolic value of expression of 's', and update
- * anything it defines in the value table 'val'. If 'alter' is true,
- * do various optimizations. This code would be cleaner if symbolic
- * evaluation and code transformations weren't folded together.
- */
-static void
-opt_stmt(s, val, alter)
- struct stmt *s;
- int val[];
- int alter;
-{
- int op;
- int v;
-
- switch (s->code) {
-
- case BPF_LD|BPF_ABS|BPF_W:
- case BPF_LD|BPF_ABS|BPF_H:
- case BPF_LD|BPF_ABS|BPF_B:
- v = F(s->code, s->k, 0L);
- vstore(s, &val[A_ATOM], v, alter);
- break;
-
- case BPF_LD|BPF_IND|BPF_W:
- case BPF_LD|BPF_IND|BPF_H:
- case BPF_LD|BPF_IND|BPF_B:
- v = val[X_ATOM];
- if (alter && vmap[v].is_const) {
- s->code = BPF_LD|BPF_ABS|BPF_SIZE(s->code);
- s->k += vmap[v].const_val;
- v = F(s->code, s->k, 0L);
- done = 0;
- }
- else
- v = F(s->code, s->k, v);
- vstore(s, &val[A_ATOM], v, alter);
- break;
-
- case BPF_LD|BPF_LEN:
- v = F(s->code, 0L, 0L);
- vstore(s, &val[A_ATOM], v, alter);
- break;
-
- case BPF_LD|BPF_IMM:
- v = K(s->k);
- vstore(s, &val[A_ATOM], v, alter);
- break;
-
- case BPF_LDX|BPF_IMM:
- v = K(s->k);
- vstore(s, &val[X_ATOM], v, alter);
- break;
-
- case BPF_LDX|BPF_MSH|BPF_B:
- v = F(s->code, s->k, 0L);
- vstore(s, &val[X_ATOM], v, alter);
- break;
-
- case BPF_ALU|BPF_NEG:
- if (alter && vmap[val[A_ATOM]].is_const) {
- s->code = BPF_LD|BPF_IMM;
- s->k = -vmap[val[A_ATOM]].const_val;
- val[A_ATOM] = K(s->k);
- }
- else
- val[A_ATOM] = F(s->code, val[A_ATOM], 0L);
- break;
-
- case BPF_ALU|BPF_ADD|BPF_K:
- case BPF_ALU|BPF_SUB|BPF_K:
- case BPF_ALU|BPF_MUL|BPF_K:
- case BPF_ALU|BPF_DIV|BPF_K:
- case BPF_ALU|BPF_AND|BPF_K:
- case BPF_ALU|BPF_OR|BPF_K:
- case BPF_ALU|BPF_LSH|BPF_K:
- case BPF_ALU|BPF_RSH|BPF_K:
- op = BPF_OP(s->code);
- if (alter) {
- if (s->k == 0) {
- if (op == BPF_ADD || op == BPF_SUB ||
- op == BPF_LSH || op == BPF_RSH ||
- op == BPF_OR) {
- s->code = NOP;
- break;
- }
- if (op == BPF_MUL || op == BPF_AND) {
- s->code = BPF_LD|BPF_IMM;
- val[A_ATOM] = K(s->k);
- break;
- }
- }
- if (vmap[val[A_ATOM]].is_const) {
- fold_op(s, val[A_ATOM], K(s->k));
- val[A_ATOM] = K(s->k);
- break;
- }
- }
- val[A_ATOM] = F(s->code, val[A_ATOM], K(s->k));
- break;
-
- case BPF_ALU|BPF_ADD|BPF_X:
- case BPF_ALU|BPF_SUB|BPF_X:
- case BPF_ALU|BPF_MUL|BPF_X:
- case BPF_ALU|BPF_DIV|BPF_X:
- case BPF_ALU|BPF_AND|BPF_X:
- case BPF_ALU|BPF_OR|BPF_X:
- case BPF_ALU|BPF_LSH|BPF_X:
- case BPF_ALU|BPF_RSH|BPF_X:
- op = BPF_OP(s->code);
- if (alter && vmap[val[X_ATOM]].is_const) {
- if (vmap[val[A_ATOM]].is_const) {
- fold_op(s, val[A_ATOM], val[X_ATOM]);
- val[A_ATOM] = K(s->k);
- }
- else {
- s->code = BPF_ALU|BPF_K|op;
- s->k = vmap[val[X_ATOM]].const_val;
- done = 0;
- val[A_ATOM] =
- F(s->code, val[A_ATOM], K(s->k));
- }
- break;
- }
- /*
- * Check if we're doing something to an accumulator
- * that is 0, and simplify. This may not seem like
- * much of a simplification but it could open up further
- * optimizations.
- * XXX We could also check for mul by 1, and -1, etc.
- */
- if (alter && vmap[val[A_ATOM]].is_const
- && vmap[val[A_ATOM]].const_val == 0) {
- if (op == BPF_ADD || op == BPF_OR ||
- op == BPF_LSH || op == BPF_RSH || op == BPF_SUB) {
- s->code = BPF_MISC|BPF_TXA;
- vstore(s, &val[A_ATOM], val[X_ATOM], alter);
- break;
- }
- else if (op == BPF_MUL || op == BPF_DIV ||
- op == BPF_AND) {
- s->code = BPF_LD|BPF_IMM;
- s->k = 0;
- vstore(s, &val[A_ATOM], K(s->k), alter);
- break;
- }
- else if (op == BPF_NEG) {
- s->code = NOP;
- break;
- }
- }
- val[A_ATOM] = F(s->code, val[A_ATOM], val[X_ATOM]);
- break;
-
- case BPF_MISC|BPF_TXA:
- vstore(s, &val[A_ATOM], val[X_ATOM], alter);
- break;
-
- case BPF_LD|BPF_MEM:
- v = val[s->k];
- if (alter && vmap[v].is_const) {
- s->code = BPF_LD|BPF_IMM;
- s->k = vmap[v].const_val;
- done = 0;
- }
- vstore(s, &val[A_ATOM], v, alter);
- break;
-
- case BPF_MISC|BPF_TAX:
- vstore(s, &val[X_ATOM], val[A_ATOM], alter);
- break;
-
- case BPF_LDX|BPF_MEM:
- v = val[s->k];
- if (alter && vmap[v].is_const) {
- s->code = BPF_LDX|BPF_IMM;
- s->k = vmap[v].const_val;
- done = 0;
- }
- vstore(s, &val[X_ATOM], v, alter);
- break;
-
- case BPF_ST:
- vstore(s, &val[s->k], val[A_ATOM], alter);
- break;
-
- case BPF_STX:
- vstore(s, &val[s->k], val[X_ATOM], alter);
- break;
- }
-}
-
-static void
-deadstmt(s, last)
- register struct stmt *s;
- register struct stmt *last[];
-{
- register int atom;
-
- atom = atomuse(s);
- if (atom >= 0) {
- if (atom == AX_ATOM) {
- last[X_ATOM] = 0;
- last[A_ATOM] = 0;
- }
- else
- last[atom] = 0;
- }
- atom = atomdef(s);
- if (atom >= 0) {
- if (last[atom]) {
- done = 0;
- last[atom]->code = NOP;
- }
- last[atom] = s;
- }
-}
-
-static void
-opt_deadstores(b)
- register struct block *b;
-{
- register struct slist *s;
- register int atom;
- struct stmt *last[N_ATOMS];
-
- memset((char *)last, 0, sizeof last);
-
- for (s = b->stmts; s != 0; s = s->next)
- deadstmt(&s->s, last);
- deadstmt(&b->s, last);
-
- for (atom = 0; atom < N_ATOMS; ++atom)
- if (last[atom] && !ATOMELEM(b->out_use, atom)) {
- last[atom]->code = NOP;
- done = 0;
- }
-}
-
-static void
-opt_blk(b, do_stmts)
- struct block *b;
- int do_stmts;
-{
- struct slist *s;
- struct edge *p;
- int i;
- bpf_int32 aval;
-
- /*
- * Initialize the atom values.
- * If we have no predecessors, everything is undefined.
- * Otherwise, we inherent our values from our predecessors.
- * If any register has an ambiguous value (i.e. control paths are
- * merging) give it the undefined value of 0.
- */
- p = b->in_edges;
- if (p == 0)
- memset((char *)b->val, 0, sizeof(b->val));
- else {
- memcpy((char *)b->val, (char *)p->pred->val, sizeof(b->val));
- while ((p = p->next) != NULL) {
- for (i = 0; i < N_ATOMS; ++i)
- if (b->val[i] != p->pred->val[i])
- b->val[i] = 0;
- }
- }
- aval = b->val[A_ATOM];
- for (s = b->stmts; s; s = s->next)
- opt_stmt(&s->s, b->val, do_stmts);
-
- /*
- * This is a special case: if we don't use anything from this
- * block, and we load the accumulator with value that is
- * already there, or if this block is a return,
- * eliminate all the statements.
- */
- if (do_stmts &&
- ((b->out_use == 0 && aval != 0 &&b->val[A_ATOM] == aval) ||
- BPF_CLASS(b->s.code) == BPF_RET)) {
- if (b->stmts != 0) {
- b->stmts = 0;
- done = 0;
- }
- } else {
- opt_peep(b);
- opt_deadstores(b);
- }
- /*
- * Set up values for branch optimizer.
- */
- if (BPF_SRC(b->s.code) == BPF_K)
- b->oval = K(b->s.k);
- else
- b->oval = b->val[X_ATOM];
- b->et.code = b->s.code;
- b->ef.code = -b->s.code;
-}
-
-/*
- * Return true if any register that is used on exit from 'succ', has
- * an exit value that is different from the corresponding exit value
- * from 'b'.
- */
-static int
-use_conflict(b, succ)
- struct block *b, *succ;
-{
- int atom;
- atomset use = succ->out_use;
-
- if (use == 0)
- return 0;
-
- for (atom = 0; atom < N_ATOMS; ++atom)
- if (ATOMELEM(use, atom))
- if (b->val[atom] != succ->val[atom])
- return 1;
- return 0;
-}
-
-static struct block *
-fold_edge(child, ep)
- struct block *child;
- struct edge *ep;
-{
- int sense;
- int aval0, aval1, oval0, oval1;
- int code = ep->code;
-
- if (code < 0) {
- code = -code;
- sense = 0;
- } else
- sense = 1;
-
- if (child->s.code != code)
- return 0;
-
- aval0 = child->val[A_ATOM];
- oval0 = child->oval;
- aval1 = ep->pred->val[A_ATOM];
- oval1 = ep->pred->oval;
-
- if (aval0 != aval1)
- return 0;
-
- if (oval0 == oval1)
- /*
- * The operands are identical, so the
- * result is true if a true branch was
- * taken to get here, otherwise false.
- */
- return sense ? JT(child) : JF(child);
-
- if (sense && code == (BPF_JMP|BPF_JEQ|BPF_K))
- /*
- * At this point, we only know the comparison if we
- * came down the true branch, and it was an equality
- * comparison with a constant. We rely on the fact that
- * distinct constants have distinct value numbers.
- */
- return JF(child);
-
- return 0;
-}
-
-static void
-opt_j(ep)
- struct edge *ep;
-{
- register int i, k;
- register struct block *target;
-
- if (JT(ep->succ) == 0)
- return;
-
- if (JT(ep->succ) == JF(ep->succ)) {
- /*
- * Common branch targets can be eliminated, provided
- * there is no data dependency.
- */
- if (!use_conflict(ep->pred, ep->succ->et.succ)) {
- done = 0;
- ep->succ = JT(ep->succ);
- }
- }
- /*
- * For each edge dominator that matches the successor of this
- * edge, promote the edge successor to the its grandchild.
- *
- * XXX We violate the set abstraction here in favor a reasonably
- * efficient loop.
- */
- top:
- for (i = 0; i < edgewords; ++i) {
- register bpf_u_int32 x = ep->edom[i];
-
- while (x != 0) {
- k = ffs(x) - 1;
- x &=~ (1 << k);
- k += i * BITS_PER_WORD;
-
- target = fold_edge(ep->succ, edges[k]);
- /*
- * Check that there is no data dependency between
- * nodes that will be violated if we move the edge.
- */
- if (target != 0 && !use_conflict(ep->pred, target)) {
- done = 0;
- ep->succ = target;
- if (JT(target) != 0)
- /*
- * Start over unless we hit a leaf.
- */
- goto top;
- return;
- }
- }
- }
-}
-
-
-static void
-or_pullup(b)
- struct block *b;
-{
- int val, at_top;
- struct block *pull;
- struct block **diffp, **samep;
- struct edge *ep;
-
- ep = b->in_edges;
- if (ep == 0)
- return;
-
- /*
- * Make sure each predecessor loads the same value.
- * XXX why?
- */
- val = ep->pred->val[A_ATOM];
- for (ep = ep->next; ep != 0; ep = ep->next)
- if (val != ep->pred->val[A_ATOM])
- return;
-
- if (JT(b->in_edges->pred) == b)
- diffp = &JT(b->in_edges->pred);
- else
- diffp = &JF(b->in_edges->pred);
-
- at_top = 1;
- while (1) {
- if (*diffp == 0)
- return;
-
- if (JT(*diffp) != JT(b))
- return;
-
- if (!SET_MEMBER((*diffp)->dom, b->id))
- return;
-
- if ((*diffp)->val[A_ATOM] != val)
- break;
-
- diffp = &JF(*diffp);
- at_top = 0;
- }
- samep = &JF(*diffp);
- while (1) {
- if (*samep == 0)
- return;
-
- if (JT(*samep) != JT(b))
- return;
-
- if (!SET_MEMBER((*samep)->dom, b->id))
- return;
-
- if ((*samep)->val[A_ATOM] == val)
- break;
-
- /* XXX Need to check that there are no data dependencies
- between dp0 and dp1. Currently, the code generator
- will not produce such dependencies. */
- samep = &JF(*samep);
- }
-#ifdef notdef
- /* XXX This doesn't cover everything. */
- for (i = 0; i < N_ATOMS; ++i)
- if ((*samep)->val[i] != pred->val[i])
- return;
-#endif
- /* Pull up the node. */
- pull = *samep;
- *samep = JF(pull);
- JF(pull) = *diffp;
-
- /*
- * At the top of the chain, each predecessor needs to point at the
- * pulled up node. Inside the chain, there is only one predecessor
- * to worry about.
- */
- if (at_top) {
- for (ep = b->in_edges; ep != 0; ep = ep->next) {
- if (JT(ep->pred) == b)
- JT(ep->pred) = pull;
- else
- JF(ep->pred) = pull;
- }
- }
- else
- *diffp = pull;
-
- done = 0;
-}
-
-static void
-and_pullup(b)
- struct block *b;
-{
- int val, at_top;
- struct block *pull;
- struct block **diffp, **samep;
- struct edge *ep;
-
- ep = b->in_edges;
- if (ep == 0)
- return;
-
- /*
- * Make sure each predecessor loads the same value.
- */
- val = ep->pred->val[A_ATOM];
- for (ep = ep->next; ep != 0; ep = ep->next)
- if (val != ep->pred->val[A_ATOM])
- return;
-
- if (JT(b->in_edges->pred) == b)
- diffp = &JT(b->in_edges->pred);
- else
- diffp = &JF(b->in_edges->pred);
-
- at_top = 1;
- while (1) {
- if (*diffp == 0)
- return;
-
- if (JF(*diffp) != JF(b))
- return;
-
- if (!SET_MEMBER((*diffp)->dom, b->id))
- return;
-
- if ((*diffp)->val[A_ATOM] != val)
- break;
-
- diffp = &JT(*diffp);
- at_top = 0;
- }
- samep = &JT(*diffp);
- while (1) {
- if (*samep == 0)
- return;
-
- if (JF(*samep) != JF(b))
- return;
-
- if (!SET_MEMBER((*samep)->dom, b->id))
- return;
-
- if ((*samep)->val[A_ATOM] == val)
- break;
-
- /* XXX Need to check that there are no data dependencies
- between diffp and samep. Currently, the code generator
- will not produce such dependencies. */
- samep = &JT(*samep);
- }
-#ifdef notdef
- /* XXX This doesn't cover everything. */
- for (i = 0; i < N_ATOMS; ++i)
- if ((*samep)->val[i] != pred->val[i])
- return;
-#endif
- /* Pull up the node. */
- pull = *samep;
- *samep = JT(pull);
- JT(pull) = *diffp;
-
- /*
- * At the top of the chain, each predecessor needs to point at the
- * pulled up node. Inside the chain, there is only one predecessor
- * to worry about.
- */
- if (at_top) {
- for (ep = b->in_edges; ep != 0; ep = ep->next) {
- if (JT(ep->pred) == b)
- JT(ep->pred) = pull;
- else
- JF(ep->pred) = pull;
- }
- }
- else
- *diffp = pull;
-
- done = 0;
-}
-
-static void
-opt_blks(root, do_stmts)
- struct block *root;
- int do_stmts;
-{
- int i, maxlevel;
- struct block *p;
-
- init_val();
- maxlevel = root->level;
- for (i = maxlevel; i >= 0; --i)
- for (p = levels[i]; p; p = p->link)
- opt_blk(p, do_stmts);
-
- if (do_stmts)
- /*
- * No point trying to move branches; it can't possibly
- * make a difference at this point.
- */
- return;
-
- for (i = 1; i <= maxlevel; ++i) {
- for (p = levels[i]; p; p = p->link) {
- opt_j(&p->et);
- opt_j(&p->ef);
- }
- }
- for (i = 1; i <= maxlevel; ++i) {
- for (p = levels[i]; p; p = p->link) {
- or_pullup(p);
- and_pullup(p);
- }
- }
-}
-
-static __inline void
-link_inedge(parent, child)
- struct edge *parent;
- struct block *child;
-{
- parent->next = child->in_edges;
- child->in_edges = parent;
-}
-
-static void
-find_inedges(root)
- struct block *root;
-{
- int i;
- struct block *b;
-
- for (i = 0; i < n_blocks; ++i)
- blocks[i]->in_edges = 0;
-
- /*
- * Traverse the graph, adding each edge to the predecessor
- * list of its successors. Skip the leaves (i.e. level 0).
- */
- for (i = root->level; i > 0; --i) {
- for (b = levels[i]; b != 0; b = b->link) {
- link_inedge(&b->et, JT(b));
- link_inedge(&b->ef, JF(b));
- }
- }
-}
-
-static void
-opt_root(b)
- struct block **b;
-{
- struct slist *tmp, *s;
-
- s = (*b)->stmts;
- (*b)->stmts = 0;
- while (BPF_CLASS((*b)->s.code) == BPF_JMP && JT(*b) == JF(*b))
- *b = JT(*b);
-
- tmp = (*b)->stmts;
- if (tmp != 0)
- sappend(s, tmp);
- (*b)->stmts = s;
-
- /*
- * If the root node is a return, then there is no
- * point executing any statements (since the bpf machine
- * has no side effects).
- */
- if (BPF_CLASS((*b)->s.code) == BPF_RET)
- (*b)->stmts = 0;
-}
-
-static void
-opt_loop(root, do_stmts)
- struct block *root;
- int do_stmts;
-{
-
-#ifdef BDEBUG
- if (dflag > 1)
- opt_dump(root);
-#endif
- do {
- done = 1;
- find_levels(root);
- find_dom(root);
- find_closure(root);
- find_inedges(root);
- find_ud(root);
- find_edom(root);
- opt_blks(root, do_stmts);
-#ifdef BDEBUG
- if (dflag > 1)
- opt_dump(root);
-#endif
- } while (!done);
-}
-
-/*
- * Optimize the filter code in its dag representation.
- */
-void
-bpf_optimize(rootp)
- struct block **rootp;
-{
- struct block *root;
-
- root = *rootp;
-
- opt_init(root);
- opt_loop(root, 0);
- opt_loop(root, 1);
- intern_blocks(root);
- opt_root(rootp);
- opt_cleanup();
-}
-
-static void
-make_marks(p)
- struct block *p;
-{
- if (!isMarked(p)) {
- Mark(p);
- if (BPF_CLASS(p->s.code) != BPF_RET) {
- make_marks(JT(p));
- make_marks(JF(p));
- }
- }
-}
-
-/*
- * Mark code array such that isMarked(i) is true
- * only for nodes that are alive.
- */
-static void
-mark_code(p)
- struct block *p;
-{
- cur_mark += 1;
- make_marks(p);
-}
-
-/*
- * True iff the two stmt lists load the same value from the packet into
- * the accumulator.
- */
-static int
-eq_slist(x, y)
- struct slist *x, *y;
-{
- while (1) {
- while (x && x->s.code == NOP)
- x = x->next;
- while (y && y->s.code == NOP)
- y = y->next;
- if (x == 0)
- return y == 0;
- if (y == 0)
- return x == 0;
- if (x->s.code != y->s.code || x->s.k != y->s.k)
- return 0;
- x = x->next;
- y = y->next;
- }
-}
-
-static __inline int
-eq_blk(b0, b1)
- struct block *b0, *b1;
-{
- if (b0->s.code == b1->s.code &&
- b0->s.k == b1->s.k &&
- b0->et.succ == b1->et.succ &&
- b0->ef.succ == b1->ef.succ)
- return eq_slist(b0->stmts, b1->stmts);
- return 0;
-}
-
-static void
-intern_blocks(root)
- struct block *root;
-{
- struct block *p;
- int i, j;
- int done;
- top:
- done = 1;
- for (i = 0; i < n_blocks; ++i)
- blocks[i]->link = 0;
-
- mark_code(root);
-
- for (i = n_blocks - 1; --i >= 0; ) {
- if (!isMarked(blocks[i]))
- continue;
- for (j = i + 1; j < n_blocks; ++j) {
- if (!isMarked(blocks[j]))
- continue;
- if (eq_blk(blocks[i], blocks[j])) {
- blocks[i]->link = blocks[j]->link ?
- blocks[j]->link : blocks[j];
- break;
- }
- }
- }
- for (i = 0; i < n_blocks; ++i) {
- p = blocks[i];
- if (JT(p) == 0)
- continue;
- if (JT(p)->link) {
- done = 0;
- JT(p) = JT(p)->link;
- }
- if (JF(p)->link) {
- done = 0;
- JF(p) = JF(p)->link;
- }
- }
- if (!done)
- goto top;
-}
-
-static void
-opt_cleanup()
-{
- free((void *)vnode_base);
- free((void *)vmap);
- free((void *)edges);
- free((void *)space);
- free((void *)levels);
- free((void *)blocks);
-}
-
-/*
- * Return the number of stmts in 's'.
- */
-static int
-slength(s)
- struct slist *s;
-{
- int n = 0;
-
- for (; s; s = s->next)
- if (s->s.code != NOP)
- ++n;
- return n;
-}
-
-/*
- * Return the number of nodes reachable by 'p'.
- * All nodes should be initially unmarked.
- */
-static int
-count_blocks(p)
- struct block *p;
-{
- if (p == 0 || isMarked(p))
- return 0;
- Mark(p);
- return count_blocks(JT(p)) + count_blocks(JF(p)) + 1;
-}
-
-/*
- * Do a depth first search on the flow graph, numbering the
- * the basic blocks, and entering them into the 'blocks' array.`
- */
-static void
-number_blks_r(p)
- struct block *p;
-{
- int n;
-
- if (p == 0 || isMarked(p))
- return;
-
- Mark(p);
- n = n_blocks++;
- p->id = n;
- blocks[n] = p;
-
- number_blks_r(JT(p));
- number_blks_r(JF(p));
-}
-
-/*
- * Return the number of stmts in the flowgraph reachable by 'p'.
- * The nodes should be unmarked before calling.
- */
-static int
-count_stmts(p)
- struct block *p;
-{
- int n;
-
- if (p == 0 || isMarked(p))
- return 0;
- Mark(p);
- n = count_stmts(JT(p)) + count_stmts(JF(p));
- return slength(p->stmts) + n + 1;
-}
-
-/*
- * Allocate memory. All allocation is done before optimization
- * is begun. A linear bound on the size of all data structures is computed
- * from the total number of blocks and/or statements.
- */
-static void
-opt_init(root)
- struct block *root;
-{
- bpf_u_int32 *p;
- int i, n, max_stmts;
-
- /*
- * First, count the blocks, so we can malloc an array to map
- * block number to block. Then, put the blocks into the array.
- */
- unMarkAll();
- n = count_blocks(root);
- blocks = (struct block **)malloc(n * sizeof(*blocks));
- unMarkAll();
- n_blocks = 0;
- number_blks_r(root);
-
- n_edges = 2 * n_blocks;
- edges = (struct edge **)malloc(n_edges * sizeof(*edges));
-
- /*
- * The number of levels is bounded by the number of nodes.
- */
- levels = (struct block **)malloc(n_blocks * sizeof(*levels));
-
- edgewords = n_edges / (8 * sizeof(bpf_u_int32)) + 1;
- nodewords = n_blocks / (8 * sizeof(bpf_u_int32)) + 1;
-
- /* XXX */
- space = (bpf_u_int32 *)malloc(2 * n_blocks * nodewords * sizeof(*space)
- + n_edges * edgewords * sizeof(*space));
- p = space;
- all_dom_sets = p;
- for (i = 0; i < n; ++i) {
- blocks[i]->dom = p;
- p += nodewords;
- }
- all_closure_sets = p;
- for (i = 0; i < n; ++i) {
- blocks[i]->closure = p;
- p += nodewords;
- }
- all_edge_sets = p;
- for (i = 0; i < n; ++i) {
- register struct block *b = blocks[i];
-
- b->et.edom = p;
- p += edgewords;
- b->ef.edom = p;
- p += edgewords;
- b->et.id = i;
- edges[i] = &b->et;
- b->ef.id = n_blocks + i;
- edges[n_blocks + i] = &b->ef;
- b->et.pred = b;
- b->ef.pred = b;
- }
- max_stmts = 0;
- for (i = 0; i < n; ++i)
- max_stmts += slength(blocks[i]->stmts) + 1;
- /*
- * We allocate at most 3 value numbers per statement,
- * so this is an upper bound on the number of valnodes
- * we'll need.
- */
- maxval = 3 * max_stmts;
- vmap = (struct vmapinfo *)malloc(maxval * sizeof(*vmap));
- vnode_base = (struct valnode *)malloc(maxval * sizeof(*vmap));
-}
-
-/*
- * Some pointers used to convert the basic block form of the code,
- * into the array form that BPF requires. 'fstart' will point to
- * the malloc'd array while 'ftail' is used during the recursive traversal.
- */
-static struct bpf_insn *fstart;
-static struct bpf_insn *ftail;
-
-#ifdef BDEBUG
-int bids[1000];
-#endif
-
-/*
- * Returns true if successful. Returns false if a branch has
- * an offset that is too large. If so, we have marked that
- * branch so that on a subsequent iteration, it will be treated
- * properly.
- */
-static int
-convert_code_r(p)
- struct block *p;
-{
- struct bpf_insn *dst;
- struct slist *src;
- int slen;
- u_int off;
- int extrajmps; /* number of extra jumps inserted */
-
- if (p == 0 || isMarked(p))
- return (1);
- Mark(p);
-
- if (convert_code_r(JF(p)) == 0)
- return (0);
- if (convert_code_r(JT(p)) == 0)
- return (0);
-
- slen = slength(p->stmts);
- dst = ftail -= (slen + 1 + p->longjt + p->longjf);
- /* inflate length by any extra jumps */
-
- p->offset = dst - fstart;
-
- for (src = p->stmts; src; src = src->next) {
- if (src->s.code == NOP)
- continue;
- dst->code = (u_short)src->s.code;
- dst->k = src->s.k;
- ++dst;
- }
-#ifdef BDEBUG
- bids[dst - fstart] = p->id + 1;
-#endif
- dst->code = (u_short)p->s.code;
- dst->k = p->s.k;
- if (JT(p)) {
- extrajmps = 0;
- off = JT(p)->offset - (p->offset + slen) - 1;
- if (off >= 256) {
- /* offset too large for branch, must add a jump */
- if (p->longjt == 0) {
- /* mark this instruction and retry */
- p->longjt++;
- return(0);
- }
- /* branch if T to following jump */
- dst->jt = extrajmps;
- extrajmps++;
- dst[extrajmps].code = BPF_JMP|BPF_JA;
- dst[extrajmps].k = off - extrajmps;
- }
- else
- dst->jt = off;
- off = JF(p)->offset - (p->offset + slen) - 1;
- if (off >= 256) {
- /* offset too large for branch, must add a jump */
- if (p->longjf == 0) {
- /* mark this instruction and retry */
- p->longjf++;
- return(0);
- }
- /* branch if F to following jump */
- /* if two jumps are inserted, F goes to second one */
- dst->jf = extrajmps;
- extrajmps++;
- dst[extrajmps].code = BPF_JMP|BPF_JA;
- dst[extrajmps].k = off - extrajmps;
- }
- else
- dst->jf = off;
- }
- return (1);
-}
-
-
-/*
- * Convert flowgraph intermediate representation to the
- * BPF array representation. Set *lenp to the number of instructions.
- */
-struct bpf_insn *
-icode_to_fcode(root, lenp)
- struct block *root;
- int *lenp;
-{
- int n;
- struct bpf_insn *fp;
-
- /*
- * Loop doing convert_codr_r() until no branches remain
- * with too-large offsets.
- */
- while (1) {
- unMarkAll();
- n = *lenp = count_stmts(root);
-
- fp = (struct bpf_insn *)malloc(sizeof(*fp) * n);
- memset((char *)fp, 0, sizeof(*fp) * n);
- fstart = fp;
- ftail = fp + n;
-
- unMarkAll();
- if (convert_code_r(root))
- break;
- free(fp);
- }
-
- return fp;
-}
-
-#ifdef BDEBUG
-static void
-opt_dump(root)
- struct block *root;
-{
- struct bpf_program f;
-
- memset(bids, 0, sizeof bids);
- f.bf_insns = icode_to_fcode(root, &f.bf_len);
- bpf_dump(&f, 1);
- putchar('\n');
- free((char *)f.bf_insns);
-}
-#endif
projects / apple / network_cmds.git / commitdiff
