1996-08-19 20:36:34 +00:00
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/*
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* Copyright (c) 1988, 1989, 1990, 1991, 1993, 1994, 1995, 1996
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* The Regents of the University of California. All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that: (1) source code distributions
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* retain the above copyright notice and this paragraph in its entirety, (2)
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* distributions including binary code include the above copyright notice and
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* this paragraph in its entirety in the documentation or other materials
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* provided with the distribution, and (3) all advertising materials mentioning
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* features or use of this software display the following acknowledgement:
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* ``This product includes software developed by the University of California,
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* Lawrence Berkeley Laboratory and its contributors.'' Neither the name of
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* the University nor the names of its contributors may be used to endorse
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* or promote products derived from this software without specific prior
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* written permission.
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* THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR IMPLIED
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* WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF
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* MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
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*
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* Optimization module for tcpdump intermediate representation.
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*/
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#ifndef lint
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1997-05-27 00:01:12 +00:00
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static const char rcsid[] =
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2000-01-30 00:32:56 +00:00
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"@(#) $Header: /tcpdump/master/libpcap/optimize.c,v 1.61 1999/10/19 15:18:30 itojun Exp $ (LBL)";
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1996-08-19 20:36:34 +00:00
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#endif
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#include <sys/types.h>
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#include <sys/time.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <memory.h>
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#include "pcap-int.h"
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#include "gencode.h"
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#include "gnuc.h"
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#ifdef HAVE_OS_PROTO_H
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#include "os-proto.h"
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#endif
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#ifdef BDEBUG
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extern int dflag;
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#endif
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#define A_ATOM BPF_MEMWORDS
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#define X_ATOM (BPF_MEMWORDS+1)
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#define NOP -1
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/*
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* This define is used to represent *both* the accumulator and
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* x register in use-def computations.
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* Currently, the use-def code assumes only one definition per instruction.
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*/
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#define AX_ATOM N_ATOMS
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/*
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* A flag to indicate that further optimization is needed.
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* Iterative passes are continued until a given pass yields no
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* branch movement.
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*/
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static int done;
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/*
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* A block is marked if only if its mark equals the current mark.
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* Rather than traverse the code array, marking each item, 'cur_mark' is
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* incremented. This automatically makes each element unmarked.
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*/
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static int cur_mark;
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#define isMarked(p) ((p)->mark == cur_mark)
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#define unMarkAll() cur_mark += 1
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#define Mark(p) ((p)->mark = cur_mark)
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static void opt_init(struct block *);
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static void opt_cleanup(void);
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static void make_marks(struct block *);
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static void mark_code(struct block *);
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static void intern_blocks(struct block *);
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static int eq_slist(struct slist *, struct slist *);
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static void find_levels_r(struct block *);
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static void find_levels(struct block *);
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static void find_dom(struct block *);
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static void propedom(struct edge *);
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static void find_edom(struct block *);
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static void find_closure(struct block *);
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static int atomuse(struct stmt *);
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static int atomdef(struct stmt *);
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static void compute_local_ud(struct block *);
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static void find_ud(struct block *);
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static void init_val(void);
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static int F(int, int, int);
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static inline void vstore(struct stmt *, int *, int, int);
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static void opt_blk(struct block *, int);
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static int use_conflict(struct block *, struct block *);
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static void opt_j(struct edge *);
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static void or_pullup(struct block *);
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static void and_pullup(struct block *);
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static void opt_blks(struct block *, int);
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static inline void link_inedge(struct edge *, struct block *);
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static void find_inedges(struct block *);
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static void opt_root(struct block **);
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static void opt_loop(struct block *, int);
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static void fold_op(struct stmt *, int, int);
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static inline struct slist *this_op(struct slist *);
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static void opt_not(struct block *);
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static void opt_peep(struct block *);
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static void opt_stmt(struct stmt *, int[], int);
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static void deadstmt(struct stmt *, struct stmt *[]);
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static void opt_deadstores(struct block *);
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static void opt_blk(struct block *, int);
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static int use_conflict(struct block *, struct block *);
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static void opt_j(struct edge *);
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static struct block *fold_edge(struct block *, struct edge *);
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static inline int eq_blk(struct block *, struct block *);
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static int slength(struct slist *);
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static int count_blocks(struct block *);
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static void number_blks_r(struct block *);
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static int count_stmts(struct block *);
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static int convert_code_r(struct block *);
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#ifdef BDEBUG
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static void opt_dump(struct block *);
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#endif
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static int n_blocks;
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struct block **blocks;
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static int n_edges;
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struct edge **edges;
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/*
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* A bit vector set representation of the dominators.
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* We round up the set size to the next power of two.
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*/
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static int nodewords;
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static int edgewords;
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struct block **levels;
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bpf_u_int32 *space;
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#define BITS_PER_WORD (8*sizeof(bpf_u_int32))
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/*
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* True if a is in uset {p}
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*/
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#define SET_MEMBER(p, a) \
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((p)[(unsigned)(a) / BITS_PER_WORD] & (1 << ((unsigned)(a) % BITS_PER_WORD)))
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/*
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* Add 'a' to uset p.
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*/
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#define SET_INSERT(p, a) \
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(p)[(unsigned)(a) / BITS_PER_WORD] |= (1 << ((unsigned)(a) % BITS_PER_WORD))
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/*
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* Delete 'a' from uset p.
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*/
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#define SET_DELETE(p, a) \
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(p)[(unsigned)(a) / BITS_PER_WORD] &= ~(1 << ((unsigned)(a) % BITS_PER_WORD))
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/*
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* a := a intersect b
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*/
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#define SET_INTERSECT(a, b, n)\
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{\
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register bpf_u_int32 *_x = a, *_y = b;\
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register int _n = n;\
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while (--_n >= 0) *_x++ &= *_y++;\
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}
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/*
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* a := a - b
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*/
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#define SET_SUBTRACT(a, b, n)\
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{\
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register bpf_u_int32 *_x = a, *_y = b;\
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register int _n = n;\
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while (--_n >= 0) *_x++ &=~ *_y++;\
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}
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/*
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* a := a union b
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*/
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#define SET_UNION(a, b, n)\
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{\
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register bpf_u_int32 *_x = a, *_y = b;\
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register int _n = n;\
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while (--_n >= 0) *_x++ |= *_y++;\
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}
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static uset all_dom_sets;
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static uset all_closure_sets;
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static uset all_edge_sets;
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#ifndef MAX
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#define MAX(a,b) ((a)>(b)?(a):(b))
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#endif
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static void
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find_levels_r(b)
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struct block *b;
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{
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int level;
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if (isMarked(b))
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return;
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Mark(b);
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b->link = 0;
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if (JT(b)) {
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find_levels_r(JT(b));
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find_levels_r(JF(b));
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level = MAX(JT(b)->level, JF(b)->level) + 1;
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} else
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level = 0;
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b->level = level;
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b->link = levels[level];
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levels[level] = b;
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}
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/*
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* Level graph. The levels go from 0 at the leaves to
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* N_LEVELS at the root. The levels[] array points to the
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* first node of the level list, whose elements are linked
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* with the 'link' field of the struct block.
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*/
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static void
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find_levels(root)
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struct block *root;
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{
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memset((char *)levels, 0, n_blocks * sizeof(*levels));
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unMarkAll();
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find_levels_r(root);
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}
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/*
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* Find dominator relationships.
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* Assumes graph has been leveled.
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*/
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static void
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find_dom(root)
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struct block *root;
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{
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int i;
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struct block *b;
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bpf_u_int32 *x;
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/*
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* Initialize sets to contain all nodes.
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*/
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x = all_dom_sets;
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i = n_blocks * nodewords;
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while (--i >= 0)
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*x++ = ~0;
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/* Root starts off empty. */
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for (i = nodewords; --i >= 0;)
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root->dom[i] = 0;
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/* root->level is the highest level no found. */
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for (i = root->level; i >= 0; --i) {
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for (b = levels[i]; b; b = b->link) {
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SET_INSERT(b->dom, b->id);
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if (JT(b) == 0)
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continue;
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SET_INTERSECT(JT(b)->dom, b->dom, nodewords);
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SET_INTERSECT(JF(b)->dom, b->dom, nodewords);
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}
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}
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}
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static void
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propedom(ep)
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struct edge *ep;
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{
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SET_INSERT(ep->edom, ep->id);
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if (ep->succ) {
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SET_INTERSECT(ep->succ->et.edom, ep->edom, edgewords);
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SET_INTERSECT(ep->succ->ef.edom, ep->edom, edgewords);
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}
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}
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/*
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* Compute edge dominators.
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* Assumes graph has been leveled and predecessors established.
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*/
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static void
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find_edom(root)
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struct block *root;
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{
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int i;
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uset x;
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struct block *b;
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x = all_edge_sets;
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for (i = n_edges * edgewords; --i >= 0; )
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x[i] = ~0;
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/* root->level is the highest level no found. */
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memset(root->et.edom, 0, edgewords * sizeof(*(uset)0));
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memset(root->ef.edom, 0, edgewords * sizeof(*(uset)0));
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for (i = root->level; i >= 0; --i) {
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for (b = levels[i]; b != 0; b = b->link) {
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propedom(&b->et);
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propedom(&b->ef);
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}
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}
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}
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/*
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* Find the backwards transitive closure of the flow graph. These sets
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* are backwards in the sense that we find the set of nodes that reach
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* a given node, not the set of nodes that can be reached by a node.
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*
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* Assumes graph has been leveled.
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*/
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static void
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find_closure(root)
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struct block *root;
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{
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int i;
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struct block *b;
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/*
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* Initialize sets to contain no nodes.
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*/
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memset((char *)all_closure_sets, 0,
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n_blocks * nodewords * sizeof(*all_closure_sets));
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/* root->level is the highest level no found. */
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for (i = root->level; i >= 0; --i) {
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for (b = levels[i]; b; b = b->link) {
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SET_INSERT(b->closure, b->id);
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if (JT(b) == 0)
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continue;
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SET_UNION(JT(b)->closure, b->closure, nodewords);
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SET_UNION(JF(b)->closure, b->closure, nodewords);
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|
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}
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|
|
}
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|
|
|
}
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|
|
|
|
|
|
|
/*
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|
|
|
* Return the register number that is used by s. If A and X are both
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|
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* used, return AX_ATOM. If no register is used, return -1.
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|
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*
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|
|
* The implementation should probably change to an array access.
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|
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|
*/
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|
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static int
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|
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atomuse(s)
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|
|
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struct stmt *s;
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|
|
|
{
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|
|
register int c = s->code;
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|
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|
|
if (c == NOP)
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|
|
return -1;
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|
|
|
|
|
|
|
switch (BPF_CLASS(c)) {
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|
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|
|
case BPF_RET:
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|
|
|
return (BPF_RVAL(c) == BPF_A) ? A_ATOM :
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|
|
|
(BPF_RVAL(c) == BPF_X) ? X_ATOM : -1;
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|
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|
|
case BPF_LD:
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|
|
case BPF_LDX:
|
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|
|
return (BPF_MODE(c) == BPF_IND) ? X_ATOM :
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|
|
|
(BPF_MODE(c) == BPF_MEM) ? s->k : -1;
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|
|
|
|
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|
|
case BPF_ST:
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|
|
return A_ATOM;
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|
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|
|
|
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;
|
|
|
|
|
2000-01-30 00:32:56 +00:00
|
|
|
#if 0
|
|
|
|
for (s = b->stmts; s && s->next; s = s->next)
|
|
|
|
if (BPF_CLASS(s->s.code) == BPF_JMP) {
|
|
|
|
do_stmts = 0;
|
|
|
|
break;
|
|
|
|
}
|
|
|
|
#endif
|
|
|
|
|
1996-08-19 20:36:34 +00:00
|
|
|
/*
|
|
|
|
* 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 */
|
2000-01-30 00:32:56 +00:00
|
|
|
struct slist **offset = NULL;
|
1996-08-19 20:36:34 +00:00
|
|
|
|
|
|
|
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;
|
|
|
|
|
2000-01-30 00:32:56 +00:00
|
|
|
/* generate offset[] for convenience */
|
|
|
|
if (slen) {
|
|
|
|
offset = (struct slist **)calloc(sizeof(struct slist *), slen);
|
|
|
|
if (!offset) {
|
|
|
|
bpf_error("not enough core");
|
|
|
|
/*NOTREACHED*/
|
|
|
|
}
|
|
|
|
}
|
|
|
|
src = p->stmts;
|
|
|
|
for (off = 0; off < slen && src; off++) {
|
|
|
|
#if 0
|
|
|
|
printf("off=%d src=%x\n", off, src);
|
|
|
|
#endif
|
|
|
|
offset[off] = src;
|
|
|
|
src = src->next;
|
|
|
|
}
|
|
|
|
|
|
|
|
off = 0;
|
1996-08-19 20:36:34 +00:00
|
|
|
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;
|
2000-01-30 00:32:56 +00:00
|
|
|
|
|
|
|
/* fill block-local relative jump */
|
|
|
|
if (BPF_CLASS(src->s.code) != BPF_JMP || src->s.code == BPF_JMP|BPF_JA) {
|
|
|
|
#if 0
|
|
|
|
if (src->s.jt || src->s.jf) {
|
|
|
|
bpf_error("illegal jmp destination");
|
|
|
|
/*NOTREACHED*/
|
|
|
|
}
|
|
|
|
#endif
|
|
|
|
goto filled;
|
|
|
|
}
|
|
|
|
if (off == slen - 2) /*???*/
|
|
|
|
goto filled;
|
|
|
|
|
|
|
|
{
|
|
|
|
int i;
|
|
|
|
int jt, jf;
|
|
|
|
char *ljerr = "%s for block-local relative jump: off=%d";
|
|
|
|
|
|
|
|
#if 0
|
|
|
|
printf("code=%x off=%d %x %x\n", src->s.code,
|
|
|
|
off, src->s.jt, src->s.jf);
|
|
|
|
#endif
|
|
|
|
|
|
|
|
if (!src->s.jt || !src->s.jf) {
|
|
|
|
bpf_error(ljerr, "no jmp destination", off);
|
|
|
|
/*NOTREACHED*/
|
|
|
|
}
|
|
|
|
|
|
|
|
jt = jf = 0;
|
|
|
|
for (i = 0; i < slen; i++) {
|
|
|
|
if (offset[i] == src->s.jt) {
|
|
|
|
if (jt) {
|
|
|
|
bpf_error(ljerr, "multiple matches", off);
|
|
|
|
/*NOTREACHED*/
|
|
|
|
}
|
|
|
|
|
|
|
|
dst->jt = i - off - 1;
|
|
|
|
jt++;
|
|
|
|
}
|
|
|
|
if (offset[i] == src->s.jf) {
|
|
|
|
if (jf) {
|
|
|
|
bpf_error(ljerr, "multiple matches", off);
|
|
|
|
/*NOTREACHED*/
|
|
|
|
}
|
|
|
|
dst->jf = i - off - 1;
|
|
|
|
jf++;
|
|
|
|
}
|
|
|
|
}
|
|
|
|
if (!jt || !jf) {
|
|
|
|
bpf_error(ljerr, "no destination found", off);
|
|
|
|
/*NOTREACHED*/
|
|
|
|
}
|
|
|
|
}
|
|
|
|
filled:
|
1996-08-19 20:36:34 +00:00
|
|
|
++dst;
|
2000-01-30 00:32:56 +00:00
|
|
|
++off;
|
1996-08-19 20:36:34 +00:00
|
|
|
}
|
2000-01-30 00:32:56 +00:00
|
|
|
if (offset)
|
|
|
|
free(offset);
|
|
|
|
|
1996-08-19 20:36:34 +00:00
|
|
|
#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
|