* WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF
* MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
*
- * Optimization module for tcpdump intermediate representation.
+ * Optimization module for BPF code intermediate representation.
*/
-#ifndef lint
-static const char rcsid[] _U_ =
- "@(#) $Header: /tcpdump/master/libpcap/optimize.c,v 1.87 2007-06-11 10:04:25 guy Exp $ (LBL)";
-#endif
#ifdef HAVE_CONFIG_H
-#include "config.h"
+#include <config.h>
#endif
+#include <pcap-types.h>
+
#include <stdio.h>
#include <stdlib.h>
#include <memory.h>
#endif
#ifdef BDEBUG
-extern int dflag;
+int pcap_optimizer_debug;
#endif
-#if defined(MSDOS) && !defined(__DJGPP__)
-extern int _w32_ffs (int mask);
-#define ffs _w32_ffs
+/*
+ * lowest_set_bit().
+ *
+ * Takes a 32-bit integer as an argument.
+ *
+ * If handed a non-zero value, returns the index of the lowest set bit,
+ * counting upwards fro zero.
+ *
+ * If handed zero, the results are platform- and compiler-dependent.
+ * Keep it out of the light, don't give it any water, don't feed it
+ * after midnight, and don't pass zero to it.
+ *
+ * This is the same as the count of trailing zeroes in the word.
+ */
+#if PCAP_IS_AT_LEAST_GNUC_VERSION(3,4)
+ /*
+ * GCC 3.4 and later; we have __builtin_ctz().
+ */
+ #define lowest_set_bit(mask) __builtin_ctz(mask)
+#elif defined(_MSC_VER)
+ /*
+ * Visual Studio; we support only 2005 and later, so use
+ * _BitScanForward().
+ */
+#include <intrin.h>
+#pragma intrinsic(_BitScanForward)
+
+static __forceinline int
+lowest_set_bit(int mask)
+{
+ unsigned long bit;
+
+ /*
+ * Don't sign-extend mask if long is longer than int.
+ * (It's currently not, in MSVC, even on 64-bit platforms, but....)
+ */
+ if (_BitScanForward(&bit, (unsigned int)mask) == 0)
+ return -1; /* mask is zero */
+ return (int)bit;
+}
+#elif defined(MSDOS) && defined(__DJGPP__)
+ /*
+ * MS-DOS with DJGPP, which declares ffs() in <string.h>, which
+ * we've already included.
+ */
+ #define lowest_set_bit(mask) (ffs((mask)) - 1)
+#elif (defined(MSDOS) && defined(__WATCOMC__)) || defined(STRINGS_H_DECLARES_FFS)
+ /*
+ * MS-DOS with Watcom C, which has <strings.h> and declares ffs() there,
+ * or some other platform (UN*X conforming to a sufficient recent version
+ * of the Single UNIX Specification).
+ */
+ #include <strings.h>
+ #define lowest_set_bit(mask) (ffs((mask)) - 1)
+#else
+/*
+ * None of the above.
+ * Use a perfect-hash-function-based function.
+ */
+static int
+lowest_set_bit(int mask)
+{
+ unsigned int v = (unsigned int)mask;
+
+ static const int MultiplyDeBruijnBitPosition[32] = {
+ 0, 1, 28, 2, 29, 14, 24, 3, 30, 22, 20, 15, 25, 17, 4, 8,
+ 31, 27, 13, 23, 21, 19, 16, 7, 26, 12, 18, 6, 11, 5, 10, 9
+ };
+
+ /*
+ * We strip off all but the lowermost set bit (v & ~v),
+ * and perform a minimal perfect hash on it to look up the
+ * number of low-order zero bits in a table.
+ *
+ * See:
+ *
+ * http://7ooo.mooo.com/text/ComputingTrailingZerosHOWTO.pdf
+ *
+ * http://supertech.csail.mit.edu/papers/debruijn.pdf
+ */
+ return (MultiplyDeBruijnBitPosition[((v & -v) * 0x077CB531U) >> 27]);
+}
#endif
/*
#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.
+ * 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.
*/
-static int done;
+struct valnode {
+ int code;
+ int v0, v1;
+ int val;
+ struct valnode *next;
+};
-/*
- * 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 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
+/* Integer constants mapped with the load immediate opcode. */
+#define K(i) F(opt_state, BPF_LD|BPF_IMM|BPF_W, i, 0L)
+
+struct vmapinfo {
+ int is_const;
+ bpf_int32 const_val;
+};
-static int n_blocks;
-struct block **blocks;
-static int n_edges;
-struct edge **edges;
+typedef struct {
+ /*
+ * A flag to indicate that further optimization is needed.
+ * Iterative passes are continued until a given pass yields no
+ * branch movement.
+ */
+ int done;
+
+ int n_blocks;
+ struct block **blocks;
+ 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.
+ */
+ int nodewords;
+ int edgewords;
+ struct block **levels;
+ bpf_u_int32 *space;
-/*
- * 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}
while (--_n >= 0) *_x++ |= *_y++;\
}
-static uset all_dom_sets;
-static uset all_closure_sets;
-static uset all_edge_sets;
+ uset all_dom_sets;
+ uset all_closure_sets;
+ uset all_edge_sets;
+
+#define MODULUS 213
+ struct valnode *hashtbl[MODULUS];
+ int curval;
+ int maxval;
+
+ struct vmapinfo *vmap;
+ struct valnode *vnode_base;
+ struct valnode *next_vnode;
+} opt_state_t;
+
+typedef struct {
+ /*
+ * 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.
+ */
+ struct bpf_insn *fstart;
+ struct bpf_insn *ftail;
+} conv_state_t;
+
+static void opt_init(compiler_state_t *, opt_state_t *, struct icode *);
+static void opt_cleanup(opt_state_t *);
+
+static void intern_blocks(opt_state_t *, struct icode *);
+
+static void find_inedges(opt_state_t *, struct block *);
+#ifdef BDEBUG
+static void opt_dump(compiler_state_t *, struct icode *);
+#endif
#ifndef MAX
#define MAX(a,b) ((a)>(b)?(a):(b))
#endif
static void
-find_levels_r(b)
- struct block *b;
+find_levels_r(opt_state_t *opt_state, struct icode *ic, struct block *b)
{
int level;
- if (isMarked(b))
+ if (isMarked(ic, b))
return;
- Mark(b);
+ Mark(ic, b);
b->link = 0;
if (JT(b)) {
- find_levels_r(JT(b));
- find_levels_r(JF(b));
+ find_levels_r(opt_state, ic, JT(b));
+ find_levels_r(opt_state, ic, JF(b));
level = MAX(JT(b)->level, JF(b)->level) + 1;
} else
level = 0;
b->level = level;
- b->link = levels[level];
- levels[level] = b;
+ b->link = opt_state->levels[level];
+ opt_state->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
+ * N_LEVELS at the root. The opt_state->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;
+find_levels(opt_state_t *opt_state, struct icode *ic)
{
- memset((char *)levels, 0, n_blocks * sizeof(*levels));
- unMarkAll();
- find_levels_r(root);
+ memset((char *)opt_state->levels, 0, opt_state->n_blocks * sizeof(*opt_state->levels));
+ unMarkAll(ic);
+ find_levels_r(opt_state, ic, ic->root);
}
/*
* Assumes graph has been leveled.
*/
static void
-find_dom(root)
- struct block *root;
+find_dom(opt_state_t *opt_state, struct block *root)
{
int i;
struct block *b;
/*
* Initialize sets to contain all nodes.
*/
- x = all_dom_sets;
- i = n_blocks * nodewords;
+ x = opt_state->all_dom_sets;
+ i = opt_state->n_blocks * opt_state->nodewords;
while (--i >= 0)
*x++ = ~0;
/* Root starts off empty. */
- for (i = nodewords; --i >= 0;)
+ for (i = opt_state->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) {
+ for (b = opt_state->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);
+ SET_INTERSECT(JT(b)->dom, b->dom, opt_state->nodewords);
+ SET_INTERSECT(JF(b)->dom, b->dom, opt_state->nodewords);
}
}
}
static void
-propedom(ep)
- struct edge *ep;
+propedom(opt_state_t *opt_state, 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);
+ SET_INTERSECT(ep->succ->et.edom, ep->edom, opt_state->edgewords);
+ SET_INTERSECT(ep->succ->ef.edom, ep->edom, opt_state->edgewords);
}
}
* Assumes graph has been leveled and predecessors established.
*/
static void
-find_edom(root)
- struct block *root;
+find_edom(opt_state_t *opt_state, struct block *root)
{
int i;
uset x;
struct block *b;
- x = all_edge_sets;
- for (i = n_edges * edgewords; --i >= 0; )
+ x = opt_state->all_edge_sets;
+ for (i = opt_state->n_edges * opt_state->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));
+ memset(root->et.edom, 0, opt_state->edgewords * sizeof(*(uset)0));
+ memset(root->ef.edom, 0, opt_state->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);
+ for (b = opt_state->levels[i]; b != 0; b = b->link) {
+ propedom(opt_state, &b->et);
+ propedom(opt_state, &b->ef);
}
}
}
* Assumes graph has been leveled.
*/
static void
-find_closure(root)
- struct block *root;
+find_closure(opt_state_t *opt_state, 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));
+ memset((char *)opt_state->all_closure_sets, 0,
+ opt_state->n_blocks * opt_state->nodewords * sizeof(*opt_state->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) {
+ for (b = opt_state->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);
+ SET_UNION(JT(b)->closure, b->closure, opt_state->nodewords);
+ SET_UNION(JF(b)->closure, b->closure, opt_state->nodewords);
}
}
}
* The implementation should probably change to an array access.
*/
static int
-atomuse(s)
- struct stmt *s;
+atomuse(struct stmt *s)
{
register int c = s->code;
* The implementation should probably change to an array access.
*/
static int
-atomdef(s)
- struct stmt *s;
+atomdef(struct stmt *s)
{
if (s->code == NOP)
return -1;
* register by a predecessor block of this block.
*/
static void
-compute_local_ud(b)
- struct block *b;
+compute_local_ud(struct block *b)
{
struct slist *s;
- atomset def = 0, use = 0, kill = 0;
+ atomset def = 0, use = 0, killed = 0;
int atom;
for (s = b->stmts; s; s = s->next) {
atom = atomdef(&s->s);
if (atom >= 0) {
if (!ATOMELEM(use, atom))
- kill |= ATOMMASK(atom);
+ killed |= ATOMMASK(atom);
def |= ATOMMASK(atom);
}
}
}
b->def = def;
- b->kill = kill;
+ b->kill = killed;
b->in_use = use;
}
* Assume graph is already leveled.
*/
static void
-find_ud(root)
- struct block *root;
+find_ud(opt_state_t *opt_state, struct block *root)
{
int i, maxlevel;
struct block *p;
*/
maxlevel = root->level;
for (i = maxlevel; i >= 0; --i)
- for (p = levels[i]; p; p = p->link) {
+ for (p = opt_state->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) {
+ for (p = opt_state->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()
+init_val(opt_state_t *opt_state)
{
- curval = 0;
- next_vnode = vnode_base;
- memset((char *)vmap, 0, maxval * sizeof(*vmap));
- memset((char *)hashtbl, 0, sizeof hashtbl);
+ opt_state->curval = 0;
+ opt_state->next_vnode = opt_state->vnode_base;
+ memset((char *)opt_state->vmap, 0, opt_state->maxval * sizeof(*opt_state->vmap));
+ memset((char *)opt_state->hashtbl, 0, sizeof opt_state->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;
+F(opt_state_t *opt_state, int code, int v0, int v1)
{
u_int hash;
int val;
hash = (u_int)code ^ (v0 << 4) ^ (v1 << 8);
hash %= MODULUS;
- for (p = hashtbl[hash]; p; p = p->next)
+ for (p = opt_state->hashtbl[hash]; p; p = p->next)
if (p->code == code && p->v0 == v0 && p->v1 == v1)
return p->val;
- val = ++curval;
+ val = ++opt_state->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;
+ opt_state->vmap[val].const_val = v0;
+ opt_state->vmap[val].is_const = 1;
}
- p = next_vnode++;
+ p = opt_state->next_vnode++;
p->val = val;
p->code = code;
p->v0 = v0;
p->v1 = v1;
- p->next = hashtbl[hash];
- hashtbl[hash] = p;
+ p->next = opt_state->hashtbl[hash];
+ opt_state->hashtbl[hash] = p;
return val;
}
static inline void
-vstore(s, valp, newval, alter)
- struct stmt *s;
- int *valp;
- int newval;
- int alter;
+vstore(struct stmt *s, int *valp, int newval, int alter)
{
- if (alter && *valp == newval)
+ if (alter && newval != VAL_UNKNOWN && *valp == newval)
s->code = NOP;
else
*valp = newval;
}
+/*
+ * Do constant-folding on binary operators.
+ * (Unary operators are handled elsewhere.)
+ */
static void
-fold_op(s, v0, v1)
- struct stmt *s;
- int v0, v1;
+fold_op(compiler_state_t *cstate, struct icode *ic, opt_state_t *opt_state,
+ struct stmt *s, int v0, int v1)
{
bpf_u_int32 a, b;
- a = vmap[v0].const_val;
- b = vmap[v1].const_val;
+ a = opt_state->vmap[v0].const_val;
+ b = opt_state->vmap[v1].const_val;
switch (BPF_OP(s->code)) {
case BPF_ADD:
case BPF_DIV:
if (b == 0)
- bpf_error("division by zero");
+ bpf_error(cstate, "division by zero");
a /= b;
break;
+ case BPF_MOD:
+ if (b == 0)
+ bpf_error(cstate, "modulus by zero");
+ a %= b;
+ break;
+
case BPF_AND:
a &= b;
break;
a |= b;
break;
+ case BPF_XOR:
+ a ^= b;
+ break;
+
case BPF_LSH:
a <<= b;
break;
a >>= b;
break;
- case BPF_NEG:
- a = -a;
- break;
-
default:
abort();
}
s->k = a;
s->code = BPF_LD|BPF_IMM;
- done = 0;
+ opt_state->done = 0;
}
static inline struct slist *
-this_op(s)
- struct slist *s;
+this_op(struct slist *s)
{
while (s != 0 && s->s.code == NOP)
s = s->next;
}
static void
-opt_not(b)
- struct block *b;
+opt_not(struct block *b)
{
struct block *tmp = JT(b);
}
static void
-opt_peep(b)
- struct block *b;
+opt_peep(opt_state_t *opt_state, struct block *b)
{
struct slist *s;
struct slist *next, *last;
if (s->s.code == BPF_ST &&
next->s.code == (BPF_LDX|BPF_MEM) &&
s->s.k == next->s.k) {
- done = 0;
+ opt_state->done = 0;
next->s.code = BPF_MISC|BPF_TAX;
}
/*
next->s.code == (BPF_MISC|BPF_TAX)) {
s->s.code = BPF_LDX|BPF_IMM;
next->s.code = BPF_MISC|BPF_TXA;
- done = 0;
+ opt_state->done = 0;
}
/*
* This is an ugly special case, but it happens
s->s.code = NOP;
add->s.code = NOP;
tax->s.code = NOP;
- done = 0;
+ opt_state->done = 0;
}
}
/*
*/
if (last->s.code == (BPF_ALU|BPF_SUB|BPF_X)) {
val = b->val[X_ATOM];
- if (vmap[val].is_const) {
+ if (opt_state->vmap[val].is_const) {
/*
* If we have a subtract to do a comparison,
* and the X register is a known constant,
* sub x -> nop
* jeq #y jeq #(x+y)
*/
- b->s.k += vmap[val].const_val;
+ b->s.k += opt_state->vmap[val].const_val;
last->s.code = NOP;
- done = 0;
+ opt_state->done = 0;
} else if (b->s.k == 0) {
/*
* If the X register isn't a constant,
*/
last->s.code = NOP;
b->s.code = BPF_JMP|BPF_JEQ|BPF_X;
- done = 0;
+ opt_state->done = 0;
}
}
/*
else if (last->s.code == (BPF_ALU|BPF_SUB|BPF_K)) {
last->s.code = NOP;
b->s.k += last->s.k;
- done = 0;
+ opt_state->done = 0;
}
/*
* And, similarly, a constant AND can be simplified
b->s.k = last->s.k;
b->s.code = BPF_JMP|BPF_K|BPF_JSET;
last->s.code = NOP;
- done = 0;
+ opt_state->done = 0;
opt_not(b);
}
}
if (b->s.code == (BPF_JMP|BPF_K|BPF_JSET)) {
if (b->s.k == 0)
JT(b) = JF(b);
- if (b->s.k == 0xffffffff)
+ if ((u_int)b->s.k == 0xffffffffU)
JF(b) = JT(b);
}
/*
* constant.
*/
val = b->val[X_ATOM];
- if (vmap[val].is_const && BPF_SRC(b->s.code) == BPF_X) {
- bpf_int32 v = vmap[val].const_val;
+ if (opt_state->vmap[val].is_const && BPF_SRC(b->s.code) == BPF_X) {
+ bpf_int32 v = opt_state->vmap[val].const_val;
b->s.code &= ~BPF_X;
b->s.k = v;
}
* 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;
+ if (opt_state->vmap[val].is_const && BPF_SRC(b->s.code) == BPF_K) {
+ bpf_int32 v = opt_state->vmap[val].const_val;
switch (BPF_OP(b->s.code)) {
case BPF_JEQ:
break;
case BPF_JGT:
- v = (unsigned)v > b->s.k;
+ v = (unsigned)v > (unsigned)b->s.k;
break;
case BPF_JGE:
- v = (unsigned)v >= b->s.k;
+ v = (unsigned)v >= (unsigned)b->s.k;
break;
case BPF_JSET:
abort();
}
if (JF(b) != JT(b))
- done = 0;
+ opt_state->done = 0;
if (v)
JF(b) = JT(b);
else
* evaluation and code transformations weren't folded together.
*/
static void
-opt_stmt(s, val, alter)
- struct stmt *s;
- int val[];
- int alter;
+opt_stmt(compiler_state_t *cstate, struct icode *ic, opt_state_t *opt_state,
+ struct stmt *s, int val[], int alter)
{
int op;
int v;
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);
+ v = F(opt_state, s->code, s->k, 0L);
vstore(s, &val[A_ATOM], v, alter);
break;
case BPF_LD|BPF_IND|BPF_H:
case BPF_LD|BPF_IND|BPF_B:
v = val[X_ATOM];
- if (alter && vmap[v].is_const) {
+ if (alter && opt_state->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;
+ s->k += opt_state->vmap[v].const_val;
+ v = F(opt_state, s->code, s->k, 0L);
+ opt_state->done = 0;
}
else
- v = F(s->code, s->k, v);
+ v = F(opt_state, s->code, s->k, v);
vstore(s, &val[A_ATOM], v, alter);
break;
case BPF_LD|BPF_LEN:
- v = F(s->code, 0L, 0L);
+ v = F(opt_state, s->code, 0L, 0L);
vstore(s, &val[A_ATOM], v, alter);
break;
break;
case BPF_LDX|BPF_MSH|BPF_B:
- v = F(s->code, s->k, 0L);
+ v = F(opt_state, 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) {
+ if (alter && opt_state->vmap[val[A_ATOM]].is_const) {
s->code = BPF_LD|BPF_IMM;
- s->k = -vmap[val[A_ATOM]].const_val;
+ s->k = -opt_state->vmap[val[A_ATOM]].const_val;
val[A_ATOM] = K(s->k);
}
else
- val[A_ATOM] = F(s->code, val[A_ATOM], 0L);
+ val[A_ATOM] = F(opt_state, 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_MOD|BPF_K:
case BPF_ALU|BPF_AND|BPF_K:
case BPF_ALU|BPF_OR|BPF_K:
+ case BPF_ALU|BPF_XOR|BPF_K:
case BPF_ALU|BPF_LSH|BPF_K:
case BPF_ALU|BPF_RSH|BPF_K:
op = BPF_OP(s->code);
* fixup the generated math code */
if (op == BPF_ADD ||
op == BPF_LSH || op == BPF_RSH ||
- op == BPF_OR) {
+ op == BPF_OR || op == BPF_XOR) {
s->code = NOP;
break;
}
break;
}
}
- if (vmap[val[A_ATOM]].is_const) {
- fold_op(s, val[A_ATOM], K(s->k));
+ if (opt_state->vmap[val[A_ATOM]].is_const) {
+ fold_op(cstate, ic, opt_state, 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));
+ val[A_ATOM] = F(opt_state, 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_MOD|BPF_X:
case BPF_ALU|BPF_AND|BPF_X:
case BPF_ALU|BPF_OR|BPF_X:
+ case BPF_ALU|BPF_XOR|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]);
+ if (alter && opt_state->vmap[val[X_ATOM]].is_const) {
+ if (opt_state->vmap[val[A_ATOM]].is_const) {
+ fold_op(cstate, ic, opt_state, 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;
+ s->k = opt_state->vmap[val[X_ATOM]].const_val;
+ opt_state->done = 0;
val[A_ATOM] =
- F(s->code, val[A_ATOM], K(s->k));
+ F(opt_state, s->code, val[A_ATOM], K(s->k));
}
break;
}
* optimizations.
* XXX We could also check for mul by 1, etc.
*/
- if (alter && vmap[val[A_ATOM]].is_const
- && vmap[val[A_ATOM]].const_val == 0) {
- if (op == BPF_ADD || op == BPF_OR) {
+ if (alter && opt_state->vmap[val[A_ATOM]].is_const
+ && opt_state->vmap[val[A_ATOM]].const_val == 0) {
+ if (op == BPF_ADD || op == BPF_OR || op == BPF_XOR) {
s->code = BPF_MISC|BPF_TXA;
vstore(s, &val[A_ATOM], val[X_ATOM], alter);
break;
}
- else if (op == BPF_MUL || op == BPF_DIV ||
+ else if (op == BPF_MUL || op == BPF_DIV || op == BPF_MOD ||
op == BPF_AND || op == BPF_LSH || op == BPF_RSH) {
s->code = BPF_LD|BPF_IMM;
s->k = 0;
break;
}
}
- val[A_ATOM] = F(s->code, val[A_ATOM], val[X_ATOM]);
+ val[A_ATOM] = F(opt_state, s->code, val[A_ATOM], val[X_ATOM]);
break;
case BPF_MISC|BPF_TXA:
case BPF_LD|BPF_MEM:
v = val[s->k];
- if (alter && vmap[v].is_const) {
+ if (alter && opt_state->vmap[v].is_const) {
s->code = BPF_LD|BPF_IMM;
- s->k = vmap[v].const_val;
- done = 0;
+ s->k = opt_state->vmap[v].const_val;
+ opt_state->done = 0;
}
vstore(s, &val[A_ATOM], v, alter);
break;
case BPF_LDX|BPF_MEM:
v = val[s->k];
- if (alter && vmap[v].is_const) {
+ if (alter && opt_state->vmap[v].is_const) {
s->code = BPF_LDX|BPF_IMM;
- s->k = vmap[v].const_val;
- done = 0;
+ s->k = opt_state->vmap[v].const_val;
+ opt_state->done = 0;
}
vstore(s, &val[X_ATOM], v, alter);
break;
}
static void
-deadstmt(s, last)
- register struct stmt *s;
- register struct stmt *last[];
+deadstmt(opt_state_t *opt_state, register struct stmt *s, register struct stmt *last[])
{
register int atom;
atom = atomdef(s);
if (atom >= 0) {
if (last[atom]) {
- done = 0;
+ opt_state->done = 0;
last[atom]->code = NOP;
}
last[atom] = s;
}
static void
-opt_deadstores(b)
- register struct block *b;
+opt_deadstores(opt_state_t *opt_state, register struct block *b)
{
register struct slist *s;
register int atom;
memset((char *)last, 0, sizeof last);
for (s = b->stmts; s != 0; s = s->next)
- deadstmt(&s->s, last);
- deadstmt(&b->s, last);
+ deadstmt(opt_state, &s->s, last);
+ deadstmt(opt_state, &b->s, last);
for (atom = 0; atom < N_ATOMS; ++atom)
if (last[atom] && !ATOMELEM(b->out_use, atom)) {
last[atom]->code = NOP;
- done = 0;
+ opt_state->done = 0;
}
}
static void
-opt_blk(b, do_stmts)
- struct block *b;
- int do_stmts;
+opt_blk(compiler_state_t *cstate, struct icode *ic, opt_state_t *opt_state,
+ struct block *b, int do_stmts)
{
struct slist *s;
struct edge *p;
aval = b->val[A_ATOM];
xval = b->val[X_ATOM];
for (s = b->stmts; s; s = s->next)
- opt_stmt(&s->s, b->val, do_stmts);
+ opt_stmt(cstate, ic, opt_state, &s->s, b->val, do_stmts);
/*
* This is a special case: if we don't use anything from this
* block, can we eliminate it?
*/
if (do_stmts &&
- ((b->out_use == 0 && aval != 0 && b->val[A_ATOM] == aval &&
- xval != 0 && b->val[X_ATOM] == xval) ||
+ ((b->out_use == 0 &&
+ aval != VAL_UNKNOWN && b->val[A_ATOM] == aval &&
+ xval != VAL_UNKNOWN && b->val[X_ATOM] == xval) ||
BPF_CLASS(b->s.code) == BPF_RET)) {
if (b->stmts != 0) {
b->stmts = 0;
- done = 0;
+ opt_state->done = 0;
}
} else {
- opt_peep(b);
- opt_deadstores(b);
+ opt_peep(opt_state, b);
+ opt_deadstores(opt_state, b);
}
/*
* Set up values for branch optimizer.
* from 'b'.
*/
static int
-use_conflict(b, succ)
- struct block *b, *succ;
+use_conflict(struct block *b, struct block *succ)
{
int atom;
atomset use = succ->out_use;
}
static struct block *
-fold_edge(child, ep)
- struct block *child;
- struct edge *ep;
+fold_edge(struct block *child, struct edge *ep)
{
int sense;
int aval0, aval1, oval0, oval1;
}
static void
-opt_j(ep)
- struct edge *ep;
+opt_j(opt_state_t *opt_state, struct edge *ep)
{
register int i, k;
register struct block *target;
* there is no data dependency.
*/
if (!use_conflict(ep->pred, ep->succ->et.succ)) {
- done = 0;
+ opt_state->done = 0;
ep->succ = JT(ep->succ);
}
}
* efficient loop.
*/
top:
- for (i = 0; i < edgewords; ++i) {
+ for (i = 0; i < opt_state->edgewords; ++i) {
register bpf_u_int32 x = ep->edom[i];
while (x != 0) {
- k = ffs(x) - 1;
+ k = lowest_set_bit(x);
x &=~ (1 << k);
k += i * BITS_PER_WORD;
- target = fold_edge(ep->succ, edges[k]);
+ target = fold_edge(ep->succ, opt_state->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;
+ opt_state->done = 0;
ep->succ = target;
if (JT(target) != 0)
/*
static void
-or_pullup(b)
- struct block *b;
+or_pullup(opt_state_t *opt_state, struct block *b)
{
int val, at_top;
struct block *pull;
else
*diffp = pull;
- done = 0;
+ opt_state->done = 0;
}
static void
-and_pullup(b)
- struct block *b;
+and_pullup(opt_state_t *opt_state, struct block *b)
{
int val, at_top;
struct block *pull;
else
*diffp = pull;
- done = 0;
+ opt_state->done = 0;
}
static void
-opt_blks(root, do_stmts)
- struct block *root;
- int do_stmts;
+opt_blks(compiler_state_t *cstate, opt_state_t *opt_state, struct icode *ic,
+ int do_stmts)
{
int i, maxlevel;
struct block *p;
- init_val();
- maxlevel = root->level;
+ init_val(opt_state);
+ maxlevel = ic->root->level;
- find_inedges(root);
+ find_inedges(opt_state, ic->root);
for (i = maxlevel; i >= 0; --i)
- for (p = levels[i]; p; p = p->link)
- opt_blk(p, do_stmts);
+ for (p = opt_state->levels[i]; p; p = p->link)
+ opt_blk(cstate, ic, opt_state, p, do_stmts);
if (do_stmts)
/*
return;
for (i = 1; i <= maxlevel; ++i) {
- for (p = levels[i]; p; p = p->link) {
- opt_j(&p->et);
- opt_j(&p->ef);
+ for (p = opt_state->levels[i]; p; p = p->link) {
+ opt_j(opt_state, &p->et);
+ opt_j(opt_state, &p->ef);
}
}
- find_inedges(root);
+ find_inedges(opt_state, ic->root);
for (i = 1; i <= maxlevel; ++i) {
- for (p = levels[i]; p; p = p->link) {
- or_pullup(p);
- and_pullup(p);
+ for (p = opt_state->levels[i]; p; p = p->link) {
+ or_pullup(opt_state, p);
+ and_pullup(opt_state, p);
}
}
}
static inline void
-link_inedge(parent, child)
- struct edge *parent;
- struct block *child;
+link_inedge(struct edge *parent, struct block *child)
{
parent->next = child->in_edges;
child->in_edges = parent;
}
static void
-find_inedges(root)
- struct block *root;
+find_inedges(opt_state_t *opt_state, struct block *root)
{
int i;
struct block *b;
- for (i = 0; i < n_blocks; ++i)
- blocks[i]->in_edges = 0;
+ for (i = 0; i < opt_state->n_blocks; ++i)
+ opt_state->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) {
+ for (b = opt_state->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;
+opt_root(struct block **b)
{
struct slist *tmp, *s;
}
static void
-opt_loop(root, do_stmts)
- struct block *root;
- int do_stmts;
+opt_loop(compiler_state_t *cstate, opt_state_t *opt_state, struct icode *ic,
+ int do_stmts)
{
#ifdef BDEBUG
- if (dflag > 1) {
+ if (pcap_optimizer_debug > 1) {
printf("opt_loop(root, %d) begin\n", do_stmts);
- opt_dump(root);
+ opt_dump(cstate, ic);
}
#endif
do {
- done = 1;
- find_levels(root);
- find_dom(root);
- find_closure(root);
- find_ud(root);
- find_edom(root);
- opt_blks(root, do_stmts);
+ opt_state->done = 1;
+ find_levels(opt_state, ic);
+ find_dom(opt_state, ic->root);
+ find_closure(opt_state, ic->root);
+ find_ud(opt_state, ic->root);
+ find_edom(opt_state, ic->root);
+ opt_blks(cstate, opt_state, ic, do_stmts);
#ifdef BDEBUG
- if (dflag > 1) {
- printf("opt_loop(root, %d) bottom, done=%d\n", do_stmts, done);
- opt_dump(root);
+ if (pcap_optimizer_debug > 1) {
+ printf("opt_loop(root, %d) bottom, done=%d\n", do_stmts, opt_state->done);
+ opt_dump(cstate, ic);
}
#endif
- } while (!done);
+ } while (!opt_state->done);
}
/*
* Optimize the filter code in its dag representation.
*/
void
-bpf_optimize(rootp)
- struct block **rootp;
+bpf_optimize(compiler_state_t *cstate, struct icode *ic)
{
- struct block *root;
-
- root = *rootp;
+ opt_state_t opt_state;
- opt_init(root);
- opt_loop(root, 0);
- opt_loop(root, 1);
- intern_blocks(root);
+ opt_init(cstate, &opt_state, ic);
+ opt_loop(cstate, &opt_state, ic, 0);
+ opt_loop(cstate, &opt_state, ic, 1);
+ intern_blocks(&opt_state, ic);
#ifdef BDEBUG
- if (dflag > 1) {
+ if (pcap_optimizer_debug > 1) {
printf("after intern_blocks()\n");
- opt_dump(root);
+ opt_dump(cstate, ic);
}
#endif
- opt_root(rootp);
+ opt_root(&ic->root);
#ifdef BDEBUG
- if (dflag > 1) {
+ if (pcap_optimizer_debug > 1) {
printf("after opt_root()\n");
- opt_dump(root);
+ opt_dump(cstate, ic);
}
#endif
- opt_cleanup();
+ opt_cleanup(&opt_state);
}
static void
-make_marks(p)
- struct block *p;
+make_marks(struct icode *ic, struct block *p)
{
- if (!isMarked(p)) {
- Mark(p);
+ if (!isMarked(ic, p)) {
+ Mark(ic, p);
if (BPF_CLASS(p->s.code) != BPF_RET) {
- make_marks(JT(p));
- make_marks(JF(p));
+ make_marks(ic, JT(p));
+ make_marks(ic, JF(p));
}
}
}
/*
- * Mark code array such that isMarked(i) is true
+ * Mark code array such that isMarked(ic->cur_mark, i) is true
* only for nodes that are alive.
*/
static void
-mark_code(p)
- struct block *p;
+mark_code(struct icode *ic)
{
- cur_mark += 1;
- make_marks(p);
+ ic->cur_mark += 1;
+ make_marks(ic, ic->root);
}
/*
* the accumulator.
*/
static int
-eq_slist(x, y)
- struct slist *x, *y;
+eq_slist(struct slist *x, struct slist *y)
{
while (1) {
while (x && x->s.code == NOP)
}
static inline int
-eq_blk(b0, b1)
- struct block *b0, *b1;
+eq_blk(struct block *b0, struct block *b1)
{
if (b0->s.code == b1->s.code &&
b0->s.k == b1->s.k &&
}
static void
-intern_blocks(root)
- struct block *root;
+intern_blocks(opt_state_t *opt_state, struct icode *ic)
{
struct block *p;
int i, j;
int done1; /* don't shadow global */
top:
done1 = 1;
- for (i = 0; i < n_blocks; ++i)
- blocks[i]->link = 0;
+ for (i = 0; i < opt_state->n_blocks; ++i)
+ opt_state->blocks[i]->link = 0;
- mark_code(root);
+ mark_code(ic);
- for (i = n_blocks - 1; --i >= 0; ) {
- if (!isMarked(blocks[i]))
+ for (i = opt_state->n_blocks - 1; --i >= 0; ) {
+ if (!isMarked(ic, opt_state->blocks[i]))
continue;
- for (j = i + 1; j < n_blocks; ++j) {
- if (!isMarked(blocks[j]))
+ for (j = i + 1; j < opt_state->n_blocks; ++j) {
+ if (!isMarked(ic, opt_state->blocks[j]))
continue;
- if (eq_blk(blocks[i], blocks[j])) {
- blocks[i]->link = blocks[j]->link ?
- blocks[j]->link : blocks[j];
+ if (eq_blk(opt_state->blocks[i], opt_state->blocks[j])) {
+ opt_state->blocks[i]->link = opt_state->blocks[j]->link ?
+ opt_state->blocks[j]->link : opt_state->blocks[j];
break;
}
}
}
- for (i = 0; i < n_blocks; ++i) {
- p = blocks[i];
+ for (i = 0; i < opt_state->n_blocks; ++i) {
+ p = opt_state->blocks[i];
if (JT(p) == 0)
continue;
if (JT(p)->link) {
}
static void
-opt_cleanup()
+opt_cleanup(opt_state_t *opt_state)
{
- free((void *)vnode_base);
- free((void *)vmap);
- free((void *)edges);
- free((void *)space);
- free((void *)levels);
- free((void *)blocks);
+ free((void *)opt_state->vnode_base);
+ free((void *)opt_state->vmap);
+ free((void *)opt_state->edges);
+ free((void *)opt_state->space);
+ free((void *)opt_state->levels);
+ free((void *)opt_state->blocks);
}
/*
* Return the number of stmts in 's'.
*/
-static int
-slength(s)
- struct slist *s;
+static u_int
+slength(struct slist *s)
{
- int n = 0;
+ u_int n = 0;
for (; s; s = s->next)
if (s->s.code != NOP)
* All nodes should be initially unmarked.
*/
static int
-count_blocks(p)
- struct block *p;
+count_blocks(struct icode *ic, struct block *p)
{
- if (p == 0 || isMarked(p))
+ if (p == 0 || isMarked(ic, p))
return 0;
- Mark(p);
- return count_blocks(JT(p)) + count_blocks(JF(p)) + 1;
+ Mark(ic, p);
+ return count_blocks(ic, JT(p)) + count_blocks(ic, JF(p)) + 1;
}
/*
* the basic blocks, and entering them into the 'blocks' array.`
*/
static void
-number_blks_r(p)
- struct block *p;
+number_blks_r(opt_state_t *opt_state, struct icode *ic, struct block *p)
{
int n;
- if (p == 0 || isMarked(p))
+ if (p == 0 || isMarked(ic, p))
return;
- Mark(p);
- n = n_blocks++;
+ Mark(ic, p);
+ n = opt_state->n_blocks++;
p->id = n;
- blocks[n] = p;
+ opt_state->blocks[n] = p;
- number_blks_r(JT(p));
- number_blks_r(JF(p));
+ number_blks_r(opt_state, ic, JT(p));
+ number_blks_r(opt_state, ic, JF(p));
}
/*
*
* an extra long jump if the false branch requires it (p->longjf).
*/
-static int
-count_stmts(p)
- struct block *p;
+static u_int
+count_stmts(struct icode *ic, struct block *p)
{
- int n;
+ u_int n;
- if (p == 0 || isMarked(p))
+ if (p == 0 || isMarked(ic, p))
return 0;
- Mark(p);
- n = count_stmts(JT(p)) + count_stmts(JF(p));
+ Mark(ic, p);
+ n = count_stmts(ic, JT(p)) + count_stmts(ic, JF(p));
return slength(p->stmts) + n + 1 + p->longjt + p->longjf;
}
* from the total number of blocks and/or statements.
*/
static void
-opt_init(root)
- struct block *root;
+opt_init(compiler_state_t *cstate, opt_state_t *opt_state, struct icode *ic)
{
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));
- if (blocks == NULL)
- bpf_error("malloc");
- unMarkAll();
- n_blocks = 0;
- number_blks_r(root);
-
- n_edges = 2 * n_blocks;
- edges = (struct edge **)malloc(n_edges * sizeof(*edges));
- if (edges == NULL)
- bpf_error("malloc");
+ unMarkAll(ic);
+ n = count_blocks(ic, ic->root);
+ opt_state->blocks = (struct block **)calloc(n, sizeof(*opt_state->blocks));
+ if (opt_state->blocks == NULL)
+ bpf_error(cstate, "malloc");
+ unMarkAll(ic);
+ opt_state->n_blocks = 0;
+ number_blks_r(opt_state, ic, ic->root);
+
+ opt_state->n_edges = 2 * opt_state->n_blocks;
+ opt_state->edges = (struct edge **)calloc(opt_state->n_edges, sizeof(*opt_state->edges));
+ if (opt_state->edges == NULL)
+ bpf_error(cstate, "malloc");
/*
* The number of levels is bounded by the number of nodes.
*/
- levels = (struct block **)malloc(n_blocks * sizeof(*levels));
- if (levels == NULL)
- bpf_error("malloc");
+ opt_state->levels = (struct block **)calloc(opt_state->n_blocks, sizeof(*opt_state->levels));
+ if (opt_state->levels == NULL)
+ bpf_error(cstate, "malloc");
- edgewords = n_edges / (8 * sizeof(bpf_u_int32)) + 1;
- nodewords = n_blocks / (8 * sizeof(bpf_u_int32)) + 1;
+ opt_state->edgewords = opt_state->n_edges / (8 * sizeof(bpf_u_int32)) + 1;
+ opt_state->nodewords = opt_state->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));
- if (space == NULL)
- bpf_error("malloc");
- p = space;
- all_dom_sets = p;
+ opt_state->space = (bpf_u_int32 *)malloc(2 * opt_state->n_blocks * opt_state->nodewords * sizeof(*opt_state->space)
+ + opt_state->n_edges * opt_state->edgewords * sizeof(*opt_state->space));
+ if (opt_state->space == NULL)
+ bpf_error(cstate, "malloc");
+ p = opt_state->space;
+ opt_state->all_dom_sets = p;
for (i = 0; i < n; ++i) {
- blocks[i]->dom = p;
- p += nodewords;
+ opt_state->blocks[i]->dom = p;
+ p += opt_state->nodewords;
}
- all_closure_sets = p;
+ opt_state->all_closure_sets = p;
for (i = 0; i < n; ++i) {
- blocks[i]->closure = p;
- p += nodewords;
+ opt_state->blocks[i]->closure = p;
+ p += opt_state->nodewords;
}
- all_edge_sets = p;
+ opt_state->all_edge_sets = p;
for (i = 0; i < n; ++i) {
- register struct block *b = blocks[i];
+ register struct block *b = opt_state->blocks[i];
b->et.edom = p;
- p += edgewords;
+ p += opt_state->edgewords;
b->ef.edom = p;
- p += edgewords;
+ p += opt_state->edgewords;
b->et.id = i;
- edges[i] = &b->et;
- b->ef.id = n_blocks + i;
- edges[n_blocks + i] = &b->ef;
+ opt_state->edges[i] = &b->et;
+ b->ef.id = opt_state->n_blocks + i;
+ opt_state->edges[opt_state->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;
+ max_stmts += slength(opt_state->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(*vnode_base));
- if (vmap == NULL || vnode_base == NULL)
- bpf_error("malloc");
+ opt_state->maxval = 3 * max_stmts;
+ opt_state->vmap = (struct vmapinfo *)calloc(opt_state->maxval, sizeof(*opt_state->vmap));
+ opt_state->vnode_base = (struct valnode *)calloc(opt_state->maxval, sizeof(*opt_state->vnode_base));
+ if (opt_state->vmap == NULL || opt_state->vnode_base == NULL)
+ bpf_error(cstate, "malloc");
}
/*
- * 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.
+ * This is only used when supporting optimizer debugging. It is
+ * global state, so do *not* do more than one compile in parallel
+ * and expect it to provide meaningful information.
*/
-static struct bpf_insn *fstart;
-static struct bpf_insn *ftail;
-
#ifdef BDEBUG
int bids[1000];
#endif
* properly.
*/
static int
-convert_code_r(p)
- struct block *p;
+convert_code_r(compiler_state_t *cstate, conv_state_t *conv_state,
+ struct icode *ic, struct block *p)
{
struct bpf_insn *dst;
struct slist *src;
- int slen;
+ u_int slen;
u_int off;
int extrajmps; /* number of extra jumps inserted */
struct slist **offset = NULL;
- if (p == 0 || isMarked(p))
+ if (p == 0 || isMarked(ic, p))
return (1);
- Mark(p);
+ Mark(ic, p);
- if (convert_code_r(JF(p)) == 0)
+ if (convert_code_r(cstate, conv_state, ic, JF(p)) == 0)
return (0);
- if (convert_code_r(JT(p)) == 0)
+ if (convert_code_r(cstate, conv_state, ic, JT(p)) == 0)
return (0);
slen = slength(p->stmts);
- dst = ftail -= (slen + 1 + p->longjt + p->longjf);
+ dst = conv_state->ftail -= (slen + 1 + p->longjt + p->longjf);
/* inflate length by any extra jumps */
- p->offset = dst - fstart;
+ p->offset = (int)(dst - conv_state->fstart);
/* generate offset[] for convenience */
if (slen) {
offset = (struct slist **)calloc(slen, sizeof(struct slist *));
if (!offset) {
- bpf_error("not enough core");
+ bpf_error(cstate, "not enough core");
/*NOTREACHED*/
}
}
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");
+ bpf_error(cstate, "illegal jmp destination");
/*NOTREACHED*/
}
#endif
goto filled;
{
- int i;
+ u_int i;
int jt, jf;
const char *ljerr = "%s for block-local relative jump: off=%d";
#endif
if (!src->s.jt || !src->s.jf) {
- bpf_error(ljerr, "no jmp destination", off);
+ bpf_error(cstate, ljerr, "no jmp destination", off);
/*NOTREACHED*/
}
for (i = 0; i < slen; i++) {
if (offset[i] == src->s.jt) {
if (jt) {
- bpf_error(ljerr, "multiple matches", off);
+ bpf_error(cstate, ljerr, "multiple matches", off);
/*NOTREACHED*/
}
}
if (offset[i] == src->s.jf) {
if (jf) {
- bpf_error(ljerr, "multiple matches", off);
+ bpf_error(cstate, ljerr, "multiple matches", off);
/*NOTREACHED*/
}
dst->jf = i - off - 1;
}
}
if (!jt || !jf) {
- bpf_error(ljerr, "no destination found", off);
+ bpf_error(cstate, ljerr, "no destination found", off);
/*NOTREACHED*/
}
}
free(offset);
#ifdef BDEBUG
- bids[dst - fstart] = p->id + 1;
+ bids[dst - conv_state->fstart] = p->id + 1;
#endif
dst->code = (u_short)p->s.code;
dst->k = p->s.k;
/*
* Convert flowgraph intermediate representation to the
* BPF array representation. Set *lenp to the number of instructions.
+ *
+ * This routine does *NOT* leak the memory pointed to by fp. It *must
+ * not* do free(fp) before returning fp; doing so would make no sense,
+ * as the BPF array pointed to by the return value of icode_to_fcode()
+ * must be valid - it's being returned for use in a bpf_program structure.
+ *
+ * If it appears that icode_to_fcode() is leaking, the problem is that
+ * the program using pcap_compile() is failing to free the memory in
+ * the BPF program when it's done - the leak is in the program, not in
+ * the routine that happens to be allocating the memory. (By analogy, if
+ * a program calls fopen() without ever calling fclose() on the FILE *,
+ * it will leak the FILE structure; the leak is not in fopen(), it's in
+ * the program.) Change the program to use pcap_freecode() when it's
+ * done with the filter program. See the pcap man page.
*/
struct bpf_insn *
-icode_to_fcode(root, lenp)
- struct block *root;
- int *lenp;
+icode_to_fcode(compiler_state_t *cstate, struct icode *ic,
+ struct block *root, u_int *lenp)
{
- int n;
+ u_int n;
struct bpf_insn *fp;
+ conv_state_t conv_state;
/*
* Loop doing convert_code_r() until no branches remain
* with too-large offsets.
*/
while (1) {
- unMarkAll();
- n = *lenp = count_stmts(root);
+ unMarkAll(ic);
+ n = *lenp = count_stmts(ic, root);
fp = (struct bpf_insn *)malloc(sizeof(*fp) * n);
if (fp == NULL)
- bpf_error("malloc");
+ bpf_error(cstate, "malloc");
memset((char *)fp, 0, sizeof(*fp) * n);
- fstart = fp;
- ftail = fp + n;
+ conv_state.fstart = fp;
+ conv_state.ftail = fp + n;
- unMarkAll();
- if (convert_code_r(root))
+ unMarkAll(ic);
+ if (convert_code_r(cstate, &conv_state, ic, root))
break;
free(fp);
}
{
size_t prog_size;
+ /*
+ * Validate the program.
+ */
+ if (!bpf_validate(fp->bf_insns, fp->bf_len)) {
+ pcap_snprintf(p->errbuf, sizeof(p->errbuf),
+ "BPF program is not valid");
+ return (-1);
+ }
+
/*
* Free up any already installed program.
*/
p->fcode.bf_len = fp->bf_len;
p->fcode.bf_insns = (struct bpf_insn *)malloc(prog_size);
if (p->fcode.bf_insns == NULL) {
- snprintf(p->errbuf, sizeof(p->errbuf),
- "malloc: %s", pcap_strerror(errno));
+ pcap_fmt_errmsg_for_errno(p->errbuf, sizeof(p->errbuf),
+ errno, "malloc");
return (-1);
}
memcpy(p->fcode.bf_insns, fp->bf_insns, prog_size);
#ifdef BDEBUG
static void
-opt_dump(root)
- struct block *root;
+dot_dump_node(struct icode *ic, struct block *block, struct bpf_program *prog,
+ FILE *out)
+{
+ int icount, noffset;
+ int i;
+
+ if (block == NULL || isMarked(ic, block))
+ return;
+ Mark(ic, block);
+
+ icount = slength(block->stmts) + 1 + block->longjt + block->longjf;
+ noffset = min(block->offset + icount, (int)prog->bf_len);
+
+ fprintf(out, "\tblock%d [shape=ellipse, id=\"block-%d\" label=\"BLOCK%d\\n", block->id, block->id, block->id);
+ for (i = block->offset; i < noffset; i++) {
+ fprintf(out, "\\n%s", bpf_image(prog->bf_insns + i, i));
+ }
+ fprintf(out, "\" tooltip=\"");
+ for (i = 0; i < BPF_MEMWORDS; i++)
+ if (block->val[i] != VAL_UNKNOWN)
+ fprintf(out, "val[%d]=%d ", i, block->val[i]);
+ fprintf(out, "val[A]=%d ", block->val[A_ATOM]);
+ fprintf(out, "val[X]=%d", block->val[X_ATOM]);
+ fprintf(out, "\"");
+ if (JT(block) == NULL)
+ fprintf(out, ", peripheries=2");
+ fprintf(out, "];\n");
+
+ dot_dump_node(ic, JT(block), prog, out);
+ dot_dump_node(ic, JF(block), prog, out);
+}
+
+static void
+dot_dump_edge(struct icode *ic, struct block *block, FILE *out)
+{
+ if (block == NULL || isMarked(ic, block))
+ return;
+ Mark(ic, block);
+
+ if (JT(block)) {
+ fprintf(out, "\t\"block%d\":se -> \"block%d\":n [label=\"T\"]; \n",
+ block->id, JT(block)->id);
+ fprintf(out, "\t\"block%d\":sw -> \"block%d\":n [label=\"F\"]; \n",
+ block->id, JF(block)->id);
+ }
+ dot_dump_edge(ic, JT(block), out);
+ dot_dump_edge(ic, JF(block), out);
+}
+
+/* Output the block CFG using graphviz/DOT language
+ * In the CFG, block's code, value index for each registers at EXIT,
+ * and the jump relationship is show.
+ *
+ * example DOT for BPF `ip src host 1.1.1.1' is:
+ digraph BPF {
+ block0 [shape=ellipse, id="block-0" label="BLOCK0\n\n(000) ldh [12]\n(001) jeq #0x800 jt 2 jf 5" tooltip="val[A]=0 val[X]=0"];
+ block1 [shape=ellipse, id="block-1" label="BLOCK1\n\n(002) ld [26]\n(003) jeq #0x1010101 jt 4 jf 5" tooltip="val[A]=0 val[X]=0"];
+ block2 [shape=ellipse, id="block-2" label="BLOCK2\n\n(004) ret #68" tooltip="val[A]=0 val[X]=0", peripheries=2];
+ block3 [shape=ellipse, id="block-3" label="BLOCK3\n\n(005) ret #0" tooltip="val[A]=0 val[X]=0", peripheries=2];
+ "block0":se -> "block1":n [label="T"];
+ "block0":sw -> "block3":n [label="F"];
+ "block1":se -> "block2":n [label="T"];
+ "block1":sw -> "block3":n [label="F"];
+ }
+ *
+ * After install graphviz on http://www.graphviz.org/, save it as bpf.dot
+ * and run `dot -Tpng -O bpf.dot' to draw the graph.
+ */
+static void
+dot_dump(compiler_state_t *cstate, struct icode *ic)
{
struct bpf_program f;
+ FILE *out = stdout;
memset(bids, 0, sizeof bids);
- f.bf_insns = icode_to_fcode(root, &f.bf_len);
+ f.bf_insns = icode_to_fcode(cstate, ic, ic->root, &f.bf_len);
+
+ fprintf(out, "digraph BPF {\n");
+ unMarkAll(ic);
+ dot_dump_node(ic, ic->root, &f, out);
+ unMarkAll(ic);
+ dot_dump_edge(ic, ic->root, out);
+ fprintf(out, "}\n");
+
+ free((char *)f.bf_insns);
+}
+
+static void
+plain_dump(compiler_state_t *cstate, struct icode *ic)
+{
+ struct bpf_program f;
+
+ memset(bids, 0, sizeof bids);
+ f.bf_insns = icode_to_fcode(cstate, ic, ic->root, &f.bf_len);
bpf_dump(&f, 1);
putchar('\n');
free((char *)f.bf_insns);
}
+
+static void
+opt_dump(compiler_state_t *cstate, struct icode *ic)
+{
+ /* if optimizer debugging is enabled, output DOT graph
+ * `pcap_optimizer_debug=4' is equivalent to -dddd to follow -d/-dd/-ddd
+ * convention in tcpdump command line
+ */
+ if (pcap_optimizer_debug > 3)
+ dot_dump(cstate, ic);
+ else
+ plain_dump(cstate, ic);
+}
#endif
projects / libpcap / blobdiff