The Android Open Source Project | 478ab6c | 2009-03-03 19:30:05 -0800 | [diff] [blame] | 1 | /* |
| 2 | * Copyright (c) 1988, 1989, 1990, 1991, 1993, 1994, 1995, 1996 |
| 3 | * The Regents of the University of California. All rights reserved. |
| 4 | * |
| 5 | * Redistribution and use in source and binary forms, with or without |
| 6 | * modification, are permitted provided that: (1) source code distributions |
| 7 | * retain the above copyright notice and this paragraph in its entirety, (2) |
| 8 | * distributions including binary code include the above copyright notice and |
| 9 | * this paragraph in its entirety in the documentation or other materials |
| 10 | * provided with the distribution, and (3) all advertising materials mentioning |
| 11 | * features or use of this software display the following acknowledgement: |
| 12 | * ``This product includes software developed by the University of California, |
| 13 | * Lawrence Berkeley Laboratory and its contributors.'' Neither the name of |
| 14 | * the University nor the names of its contributors may be used to endorse |
| 15 | * or promote products derived from this software without specific prior |
| 16 | * written permission. |
| 17 | * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR IMPLIED |
| 18 | * WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF |
| 19 | * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. |
| 20 | * |
Haibo Huang | 165065a | 2018-07-23 17:26:52 -0700 | [diff] [blame] | 21 | * Optimization module for BPF code intermediate representation. |
The Android Open Source Project | 478ab6c | 2009-03-03 19:30:05 -0800 | [diff] [blame] | 22 | */ |
The Android Open Source Project | 478ab6c | 2009-03-03 19:30:05 -0800 | [diff] [blame] | 23 | |
| 24 | #ifdef HAVE_CONFIG_H |
Haibo Huang | 165065a | 2018-07-23 17:26:52 -0700 | [diff] [blame] | 25 | #include <config.h> |
The Android Open Source Project | 478ab6c | 2009-03-03 19:30:05 -0800 | [diff] [blame] | 26 | #endif |
| 27 | |
Haibo Huang | 165065a | 2018-07-23 17:26:52 -0700 | [diff] [blame] | 28 | #include <pcap-types.h> |
JP Abgrall | 511eca3 | 2014-02-12 13:46:45 -0800 | [diff] [blame] | 29 | |
The Android Open Source Project | 478ab6c | 2009-03-03 19:30:05 -0800 | [diff] [blame] | 30 | #include <stdio.h> |
| 31 | #include <stdlib.h> |
| 32 | #include <memory.h> |
| 33 | #include <string.h> |
| 34 | |
| 35 | #include <errno.h> |
| 36 | |
| 37 | #include "pcap-int.h" |
| 38 | |
| 39 | #include "gencode.h" |
Haibo Huang | 165065a | 2018-07-23 17:26:52 -0700 | [diff] [blame] | 40 | #include "optimize.h" |
The Android Open Source Project | 478ab6c | 2009-03-03 19:30:05 -0800 | [diff] [blame] | 41 | |
| 42 | #ifdef HAVE_OS_PROTO_H |
| 43 | #include "os-proto.h" |
| 44 | #endif |
| 45 | |
| 46 | #ifdef BDEBUG |
Elliott Hughes | 965a4b5 | 2017-05-15 10:37:39 -0700 | [diff] [blame] | 47 | /* |
Haibo Huang | 165065a | 2018-07-23 17:26:52 -0700 | [diff] [blame] | 48 | * The internal "debug printout" flag for the filter expression optimizer. |
| 49 | * The code to print that stuff is present only if BDEBUG is defined, so |
| 50 | * the flag, and the routine to set it, are defined only if BDEBUG is |
| 51 | * defined. |
Elliott Hughes | 965a4b5 | 2017-05-15 10:37:39 -0700 | [diff] [blame] | 52 | */ |
Haibo Huang | 165065a | 2018-07-23 17:26:52 -0700 | [diff] [blame] | 53 | static int pcap_optimizer_debug; |
| 54 | |
Elliott Hughes | 965a4b5 | 2017-05-15 10:37:39 -0700 | [diff] [blame] | 55 | /* |
Haibo Huang | 165065a | 2018-07-23 17:26:52 -0700 | [diff] [blame] | 56 | * Routine to set that flag. |
Elliott Hughes | 965a4b5 | 2017-05-15 10:37:39 -0700 | [diff] [blame] | 57 | * |
Haibo Huang | 165065a | 2018-07-23 17:26:52 -0700 | [diff] [blame] | 58 | * This is intended for libpcap developers, not for general use. |
| 59 | * If you want to set these in a program, you'll have to declare this |
| 60 | * routine yourself, with the appropriate DLL import attribute on Windows; |
| 61 | * it's not declared in any header file, and won't be declared in any |
| 62 | * header file provided by libpcap. |
| 63 | */ |
| 64 | PCAP_API void pcap_set_optimizer_debug(int value); |
| 65 | |
| 66 | PCAP_API_DEF void |
| 67 | pcap_set_optimizer_debug(int value) |
| 68 | { |
| 69 | pcap_optimizer_debug = value; |
| 70 | } |
| 71 | |
| 72 | /* |
| 73 | * The internal "print dot graph" flag for the filter expression optimizer. |
| 74 | * The code to print that stuff is present only if BDEBUG is defined, so |
| 75 | * the flag, and the routine to set it, are defined only if BDEBUG is |
| 76 | * defined. |
| 77 | */ |
| 78 | static int pcap_print_dot_graph; |
| 79 | |
| 80 | /* |
| 81 | * Routine to set that flag. |
| 82 | * |
| 83 | * This is intended for libpcap developers, not for general use. |
| 84 | * If you want to set these in a program, you'll have to declare this |
| 85 | * routine yourself, with the appropriate DLL import attribute on Windows; |
| 86 | * it's not declared in any header file, and won't be declared in any |
| 87 | * header file provided by libpcap. |
| 88 | */ |
| 89 | PCAP_API void pcap_set_print_dot_graph(int value); |
| 90 | |
| 91 | PCAP_API_DEF void |
| 92 | pcap_set_print_dot_graph(int value) |
| 93 | { |
| 94 | pcap_print_dot_graph = value; |
| 95 | } |
| 96 | |
| 97 | #endif |
| 98 | |
| 99 | /* |
| 100 | * lowest_set_bit(). |
| 101 | * |
| 102 | * Takes a 32-bit integer as an argument. |
| 103 | * |
| 104 | * If handed a non-zero value, returns the index of the lowest set bit, |
| 105 | * counting upwards fro zero. |
| 106 | * |
| 107 | * If handed zero, the results are platform- and compiler-dependent. |
| 108 | * Keep it out of the light, don't give it any water, don't feed it |
| 109 | * after midnight, and don't pass zero to it. |
| 110 | * |
| 111 | * This is the same as the count of trailing zeroes in the word. |
| 112 | */ |
| 113 | #if PCAP_IS_AT_LEAST_GNUC_VERSION(3,4) |
| 114 | /* |
| 115 | * GCC 3.4 and later; we have __builtin_ctz(). |
| 116 | */ |
| 117 | #define lowest_set_bit(mask) __builtin_ctz(mask) |
| 118 | #elif defined(_MSC_VER) |
| 119 | /* |
| 120 | * Visual Studio; we support only 2005 and later, so use |
| 121 | * _BitScanForward(). |
| 122 | */ |
| 123 | #include <intrin.h> |
| 124 | |
| 125 | #ifndef __clang__ |
| 126 | #pragma intrinsic(_BitScanForward) |
| 127 | #endif |
| 128 | |
| 129 | static __forceinline int |
| 130 | lowest_set_bit(int mask) |
| 131 | { |
| 132 | unsigned long bit; |
| 133 | |
| 134 | /* |
| 135 | * Don't sign-extend mask if long is longer than int. |
| 136 | * (It's currently not, in MSVC, even on 64-bit platforms, but....) |
| 137 | */ |
| 138 | if (_BitScanForward(&bit, (unsigned int)mask) == 0) |
| 139 | return -1; /* mask is zero */ |
| 140 | return (int)bit; |
| 141 | } |
| 142 | #elif defined(MSDOS) && defined(__DJGPP__) |
| 143 | /* |
| 144 | * MS-DOS with DJGPP, which declares ffs() in <string.h>, which |
| 145 | * we've already included. |
| 146 | */ |
| 147 | #define lowest_set_bit(mask) (ffs((mask)) - 1) |
| 148 | #elif (defined(MSDOS) && defined(__WATCOMC__)) || defined(STRINGS_H_DECLARES_FFS) |
| 149 | /* |
| 150 | * MS-DOS with Watcom C, which has <strings.h> and declares ffs() there, |
| 151 | * or some other platform (UN*X conforming to a sufficient recent version |
| 152 | * of the Single UNIX Specification). |
| 153 | */ |
| 154 | #include <strings.h> |
| 155 | #define lowest_set_bit(mask) (ffs((mask)) - 1) |
| 156 | #else |
| 157 | /* |
| 158 | * None of the above. |
| 159 | * Use a perfect-hash-function-based function. |
Elliott Hughes | 965a4b5 | 2017-05-15 10:37:39 -0700 | [diff] [blame] | 160 | */ |
| 161 | static int |
Haibo Huang | 165065a | 2018-07-23 17:26:52 -0700 | [diff] [blame] | 162 | lowest_set_bit(int mask) |
Elliott Hughes | 965a4b5 | 2017-05-15 10:37:39 -0700 | [diff] [blame] | 163 | { |
Haibo Huang | 165065a | 2018-07-23 17:26:52 -0700 | [diff] [blame] | 164 | unsigned int v = (unsigned int)mask; |
Elliott Hughes | 965a4b5 | 2017-05-15 10:37:39 -0700 | [diff] [blame] | 165 | |
Haibo Huang | 165065a | 2018-07-23 17:26:52 -0700 | [diff] [blame] | 166 | static const int MultiplyDeBruijnBitPosition[32] = { |
| 167 | 0, 1, 28, 2, 29, 14, 24, 3, 30, 22, 20, 15, 25, 17, 4, 8, |
| 168 | 31, 27, 13, 23, 21, 19, 16, 7, 26, 12, 18, 6, 11, 5, 10, 9 |
| 169 | }; |
| 170 | |
| 171 | /* |
| 172 | * We strip off all but the lowermost set bit (v & ~v), |
| 173 | * and perform a minimal perfect hash on it to look up the |
| 174 | * number of low-order zero bits in a table. |
| 175 | * |
| 176 | * See: |
| 177 | * |
| 178 | * http://7ooo.mooo.com/text/ComputingTrailingZerosHOWTO.pdf |
| 179 | * |
| 180 | * http://supertech.csail.mit.edu/papers/debruijn.pdf |
| 181 | */ |
| 182 | return (MultiplyDeBruijnBitPosition[((v & -v) * 0x077CB531U) >> 27]); |
Elliott Hughes | 965a4b5 | 2017-05-15 10:37:39 -0700 | [diff] [blame] | 183 | } |
JP Abgrall | 511eca3 | 2014-02-12 13:46:45 -0800 | [diff] [blame] | 184 | #endif |
| 185 | |
The Android Open Source Project | 478ab6c | 2009-03-03 19:30:05 -0800 | [diff] [blame] | 186 | /* |
| 187 | * Represents a deleted instruction. |
| 188 | */ |
| 189 | #define NOP -1 |
| 190 | |
| 191 | /* |
| 192 | * Register numbers for use-def values. |
| 193 | * 0 through BPF_MEMWORDS-1 represent the corresponding scratch memory |
| 194 | * location. A_ATOM is the accumulator and X_ATOM is the index |
| 195 | * register. |
| 196 | */ |
| 197 | #define A_ATOM BPF_MEMWORDS |
| 198 | #define X_ATOM (BPF_MEMWORDS+1) |
| 199 | |
| 200 | /* |
| 201 | * This define is used to represent *both* the accumulator and |
| 202 | * x register in use-def computations. |
| 203 | * Currently, the use-def code assumes only one definition per instruction. |
| 204 | */ |
| 205 | #define AX_ATOM N_ATOMS |
| 206 | |
| 207 | /* |
Elliott Hughes | 965a4b5 | 2017-05-15 10:37:39 -0700 | [diff] [blame] | 208 | * These data structures are used in a Cocke and Shwarz style |
| 209 | * value numbering scheme. Since the flowgraph is acyclic, |
| 210 | * exit values can be propagated from a node's predecessors |
| 211 | * provided it is uniquely defined. |
The Android Open Source Project | 478ab6c | 2009-03-03 19:30:05 -0800 | [diff] [blame] | 212 | */ |
Elliott Hughes | 965a4b5 | 2017-05-15 10:37:39 -0700 | [diff] [blame] | 213 | struct valnode { |
| 214 | int code; |
| 215 | int v0, v1; |
| 216 | int val; |
| 217 | struct valnode *next; |
| 218 | }; |
The Android Open Source Project | 478ab6c | 2009-03-03 19:30:05 -0800 | [diff] [blame] | 219 | |
Elliott Hughes | 965a4b5 | 2017-05-15 10:37:39 -0700 | [diff] [blame] | 220 | /* Integer constants mapped with the load immediate opcode. */ |
| 221 | #define K(i) F(opt_state, BPF_LD|BPF_IMM|BPF_W, i, 0L) |
The Android Open Source Project | 478ab6c | 2009-03-03 19:30:05 -0800 | [diff] [blame] | 222 | |
Elliott Hughes | 965a4b5 | 2017-05-15 10:37:39 -0700 | [diff] [blame] | 223 | struct vmapinfo { |
| 224 | int is_const; |
| 225 | bpf_int32 const_val; |
| 226 | }; |
The Android Open Source Project | 478ab6c | 2009-03-03 19:30:05 -0800 | [diff] [blame] | 227 | |
Haibo Huang | 165065a | 2018-07-23 17:26:52 -0700 | [diff] [blame] | 228 | typedef struct { |
Elliott Hughes | 965a4b5 | 2017-05-15 10:37:39 -0700 | [diff] [blame] | 229 | /* |
| 230 | * A flag to indicate that further optimization is needed. |
| 231 | * Iterative passes are continued until a given pass yields no |
| 232 | * branch movement. |
| 233 | */ |
| 234 | int done; |
The Android Open Source Project | 478ab6c | 2009-03-03 19:30:05 -0800 | [diff] [blame] | 235 | |
Elliott Hughes | 965a4b5 | 2017-05-15 10:37:39 -0700 | [diff] [blame] | 236 | int n_blocks; |
| 237 | struct block **blocks; |
| 238 | int n_edges; |
| 239 | struct edge **edges; |
The Android Open Source Project | 478ab6c | 2009-03-03 19:30:05 -0800 | [diff] [blame] | 240 | |
Elliott Hughes | 965a4b5 | 2017-05-15 10:37:39 -0700 | [diff] [blame] | 241 | /* |
| 242 | * A bit vector set representation of the dominators. |
| 243 | * We round up the set size to the next power of two. |
| 244 | */ |
| 245 | int nodewords; |
| 246 | int edgewords; |
| 247 | struct block **levels; |
| 248 | bpf_u_int32 *space; |
The Android Open Source Project | 478ab6c | 2009-03-03 19:30:05 -0800 | [diff] [blame] | 249 | |
The Android Open Source Project | 478ab6c | 2009-03-03 19:30:05 -0800 | [diff] [blame] | 250 | #define BITS_PER_WORD (8*sizeof(bpf_u_int32)) |
| 251 | /* |
| 252 | * True if a is in uset {p} |
| 253 | */ |
| 254 | #define SET_MEMBER(p, a) \ |
| 255 | ((p)[(unsigned)(a) / BITS_PER_WORD] & (1 << ((unsigned)(a) % BITS_PER_WORD))) |
| 256 | |
| 257 | /* |
| 258 | * Add 'a' to uset p. |
| 259 | */ |
| 260 | #define SET_INSERT(p, a) \ |
| 261 | (p)[(unsigned)(a) / BITS_PER_WORD] |= (1 << ((unsigned)(a) % BITS_PER_WORD)) |
| 262 | |
| 263 | /* |
| 264 | * Delete 'a' from uset p. |
| 265 | */ |
| 266 | #define SET_DELETE(p, a) \ |
| 267 | (p)[(unsigned)(a) / BITS_PER_WORD] &= ~(1 << ((unsigned)(a) % BITS_PER_WORD)) |
| 268 | |
| 269 | /* |
| 270 | * a := a intersect b |
| 271 | */ |
| 272 | #define SET_INTERSECT(a, b, n)\ |
| 273 | {\ |
| 274 | register bpf_u_int32 *_x = a, *_y = b;\ |
| 275 | register int _n = n;\ |
| 276 | while (--_n >= 0) *_x++ &= *_y++;\ |
| 277 | } |
| 278 | |
| 279 | /* |
| 280 | * a := a - b |
| 281 | */ |
| 282 | #define SET_SUBTRACT(a, b, n)\ |
| 283 | {\ |
| 284 | register bpf_u_int32 *_x = a, *_y = b;\ |
| 285 | register int _n = n;\ |
| 286 | while (--_n >= 0) *_x++ &=~ *_y++;\ |
| 287 | } |
| 288 | |
| 289 | /* |
| 290 | * a := a union b |
| 291 | */ |
| 292 | #define SET_UNION(a, b, n)\ |
| 293 | {\ |
| 294 | register bpf_u_int32 *_x = a, *_y = b;\ |
| 295 | register int _n = n;\ |
| 296 | while (--_n >= 0) *_x++ |= *_y++;\ |
| 297 | } |
| 298 | |
Elliott Hughes | 965a4b5 | 2017-05-15 10:37:39 -0700 | [diff] [blame] | 299 | uset all_dom_sets; |
| 300 | uset all_closure_sets; |
| 301 | uset all_edge_sets; |
| 302 | |
| 303 | #define MODULUS 213 |
| 304 | struct valnode *hashtbl[MODULUS]; |
| 305 | int curval; |
| 306 | int maxval; |
| 307 | |
| 308 | struct vmapinfo *vmap; |
| 309 | struct valnode *vnode_base; |
| 310 | struct valnode *next_vnode; |
Haibo Huang | 165065a | 2018-07-23 17:26:52 -0700 | [diff] [blame] | 311 | } opt_state_t; |
Elliott Hughes | 965a4b5 | 2017-05-15 10:37:39 -0700 | [diff] [blame] | 312 | |
| 313 | typedef struct { |
| 314 | /* |
| 315 | * Some pointers used to convert the basic block form of the code, |
| 316 | * into the array form that BPF requires. 'fstart' will point to |
| 317 | * the malloc'd array while 'ftail' is used during the recursive |
| 318 | * traversal. |
| 319 | */ |
| 320 | struct bpf_insn *fstart; |
| 321 | struct bpf_insn *ftail; |
| 322 | } conv_state_t; |
| 323 | |
| 324 | static void opt_init(compiler_state_t *, opt_state_t *, struct icode *); |
| 325 | static void opt_cleanup(opt_state_t *); |
| 326 | |
| 327 | static void intern_blocks(opt_state_t *, struct icode *); |
| 328 | |
| 329 | static void find_inedges(opt_state_t *, struct block *); |
| 330 | #ifdef BDEBUG |
| 331 | static void opt_dump(compiler_state_t *, struct icode *); |
| 332 | #endif |
The Android Open Source Project | 478ab6c | 2009-03-03 19:30:05 -0800 | [diff] [blame] | 333 | |
| 334 | #ifndef MAX |
| 335 | #define MAX(a,b) ((a)>(b)?(a):(b)) |
| 336 | #endif |
| 337 | |
| 338 | static void |
Elliott Hughes | 965a4b5 | 2017-05-15 10:37:39 -0700 | [diff] [blame] | 339 | find_levels_r(opt_state_t *opt_state, struct icode *ic, struct block *b) |
The Android Open Source Project | 478ab6c | 2009-03-03 19:30:05 -0800 | [diff] [blame] | 340 | { |
| 341 | int level; |
| 342 | |
Elliott Hughes | 965a4b5 | 2017-05-15 10:37:39 -0700 | [diff] [blame] | 343 | if (isMarked(ic, b)) |
The Android Open Source Project | 478ab6c | 2009-03-03 19:30:05 -0800 | [diff] [blame] | 344 | return; |
| 345 | |
Elliott Hughes | 965a4b5 | 2017-05-15 10:37:39 -0700 | [diff] [blame] | 346 | Mark(ic, b); |
The Android Open Source Project | 478ab6c | 2009-03-03 19:30:05 -0800 | [diff] [blame] | 347 | b->link = 0; |
| 348 | |
| 349 | if (JT(b)) { |
Elliott Hughes | 965a4b5 | 2017-05-15 10:37:39 -0700 | [diff] [blame] | 350 | find_levels_r(opt_state, ic, JT(b)); |
| 351 | find_levels_r(opt_state, ic, JF(b)); |
The Android Open Source Project | 478ab6c | 2009-03-03 19:30:05 -0800 | [diff] [blame] | 352 | level = MAX(JT(b)->level, JF(b)->level) + 1; |
| 353 | } else |
| 354 | level = 0; |
| 355 | b->level = level; |
Elliott Hughes | 965a4b5 | 2017-05-15 10:37:39 -0700 | [diff] [blame] | 356 | b->link = opt_state->levels[level]; |
| 357 | opt_state->levels[level] = b; |
The Android Open Source Project | 478ab6c | 2009-03-03 19:30:05 -0800 | [diff] [blame] | 358 | } |
| 359 | |
| 360 | /* |
| 361 | * Level graph. The levels go from 0 at the leaves to |
Elliott Hughes | 965a4b5 | 2017-05-15 10:37:39 -0700 | [diff] [blame] | 362 | * N_LEVELS at the root. The opt_state->levels[] array points to the |
The Android Open Source Project | 478ab6c | 2009-03-03 19:30:05 -0800 | [diff] [blame] | 363 | * first node of the level list, whose elements are linked |
| 364 | * with the 'link' field of the struct block. |
| 365 | */ |
| 366 | static void |
Elliott Hughes | 965a4b5 | 2017-05-15 10:37:39 -0700 | [diff] [blame] | 367 | find_levels(opt_state_t *opt_state, struct icode *ic) |
The Android Open Source Project | 478ab6c | 2009-03-03 19:30:05 -0800 | [diff] [blame] | 368 | { |
Elliott Hughes | 965a4b5 | 2017-05-15 10:37:39 -0700 | [diff] [blame] | 369 | memset((char *)opt_state->levels, 0, opt_state->n_blocks * sizeof(*opt_state->levels)); |
| 370 | unMarkAll(ic); |
| 371 | find_levels_r(opt_state, ic, ic->root); |
The Android Open Source Project | 478ab6c | 2009-03-03 19:30:05 -0800 | [diff] [blame] | 372 | } |
| 373 | |
| 374 | /* |
| 375 | * Find dominator relationships. |
| 376 | * Assumes graph has been leveled. |
| 377 | */ |
| 378 | static void |
Elliott Hughes | 965a4b5 | 2017-05-15 10:37:39 -0700 | [diff] [blame] | 379 | find_dom(opt_state_t *opt_state, struct block *root) |
The Android Open Source Project | 478ab6c | 2009-03-03 19:30:05 -0800 | [diff] [blame] | 380 | { |
| 381 | int i; |
| 382 | struct block *b; |
| 383 | bpf_u_int32 *x; |
| 384 | |
| 385 | /* |
| 386 | * Initialize sets to contain all nodes. |
| 387 | */ |
Elliott Hughes | 965a4b5 | 2017-05-15 10:37:39 -0700 | [diff] [blame] | 388 | x = opt_state->all_dom_sets; |
| 389 | i = opt_state->n_blocks * opt_state->nodewords; |
The Android Open Source Project | 478ab6c | 2009-03-03 19:30:05 -0800 | [diff] [blame] | 390 | while (--i >= 0) |
Haibo Huang | 165065a | 2018-07-23 17:26:52 -0700 | [diff] [blame] | 391 | *x++ = 0xFFFFFFFFU; |
The Android Open Source Project | 478ab6c | 2009-03-03 19:30:05 -0800 | [diff] [blame] | 392 | /* Root starts off empty. */ |
Elliott Hughes | 965a4b5 | 2017-05-15 10:37:39 -0700 | [diff] [blame] | 393 | for (i = opt_state->nodewords; --i >= 0;) |
The Android Open Source Project | 478ab6c | 2009-03-03 19:30:05 -0800 | [diff] [blame] | 394 | root->dom[i] = 0; |
| 395 | |
| 396 | /* root->level is the highest level no found. */ |
| 397 | for (i = root->level; i >= 0; --i) { |
Elliott Hughes | 965a4b5 | 2017-05-15 10:37:39 -0700 | [diff] [blame] | 398 | for (b = opt_state->levels[i]; b; b = b->link) { |
The Android Open Source Project | 478ab6c | 2009-03-03 19:30:05 -0800 | [diff] [blame] | 399 | SET_INSERT(b->dom, b->id); |
| 400 | if (JT(b) == 0) |
| 401 | continue; |
Elliott Hughes | 965a4b5 | 2017-05-15 10:37:39 -0700 | [diff] [blame] | 402 | SET_INTERSECT(JT(b)->dom, b->dom, opt_state->nodewords); |
| 403 | SET_INTERSECT(JF(b)->dom, b->dom, opt_state->nodewords); |
The Android Open Source Project | 478ab6c | 2009-03-03 19:30:05 -0800 | [diff] [blame] | 404 | } |
| 405 | } |
| 406 | } |
| 407 | |
| 408 | static void |
Elliott Hughes | 965a4b5 | 2017-05-15 10:37:39 -0700 | [diff] [blame] | 409 | propedom(opt_state_t *opt_state, struct edge *ep) |
The Android Open Source Project | 478ab6c | 2009-03-03 19:30:05 -0800 | [diff] [blame] | 410 | { |
| 411 | SET_INSERT(ep->edom, ep->id); |
| 412 | if (ep->succ) { |
Elliott Hughes | 965a4b5 | 2017-05-15 10:37:39 -0700 | [diff] [blame] | 413 | SET_INTERSECT(ep->succ->et.edom, ep->edom, opt_state->edgewords); |
| 414 | SET_INTERSECT(ep->succ->ef.edom, ep->edom, opt_state->edgewords); |
The Android Open Source Project | 478ab6c | 2009-03-03 19:30:05 -0800 | [diff] [blame] | 415 | } |
| 416 | } |
| 417 | |
| 418 | /* |
| 419 | * Compute edge dominators. |
| 420 | * Assumes graph has been leveled and predecessors established. |
| 421 | */ |
| 422 | static void |
Elliott Hughes | 965a4b5 | 2017-05-15 10:37:39 -0700 | [diff] [blame] | 423 | find_edom(opt_state_t *opt_state, struct block *root) |
The Android Open Source Project | 478ab6c | 2009-03-03 19:30:05 -0800 | [diff] [blame] | 424 | { |
| 425 | int i; |
| 426 | uset x; |
| 427 | struct block *b; |
| 428 | |
Elliott Hughes | 965a4b5 | 2017-05-15 10:37:39 -0700 | [diff] [blame] | 429 | x = opt_state->all_edge_sets; |
| 430 | for (i = opt_state->n_edges * opt_state->edgewords; --i >= 0; ) |
Haibo Huang | 165065a | 2018-07-23 17:26:52 -0700 | [diff] [blame] | 431 | x[i] = 0xFFFFFFFFU; |
The Android Open Source Project | 478ab6c | 2009-03-03 19:30:05 -0800 | [diff] [blame] | 432 | |
| 433 | /* root->level is the highest level no found. */ |
Elliott Hughes | 965a4b5 | 2017-05-15 10:37:39 -0700 | [diff] [blame] | 434 | memset(root->et.edom, 0, opt_state->edgewords * sizeof(*(uset)0)); |
| 435 | memset(root->ef.edom, 0, opt_state->edgewords * sizeof(*(uset)0)); |
The Android Open Source Project | 478ab6c | 2009-03-03 19:30:05 -0800 | [diff] [blame] | 436 | for (i = root->level; i >= 0; --i) { |
Elliott Hughes | 965a4b5 | 2017-05-15 10:37:39 -0700 | [diff] [blame] | 437 | for (b = opt_state->levels[i]; b != 0; b = b->link) { |
| 438 | propedom(opt_state, &b->et); |
| 439 | propedom(opt_state, &b->ef); |
The Android Open Source Project | 478ab6c | 2009-03-03 19:30:05 -0800 | [diff] [blame] | 440 | } |
| 441 | } |
| 442 | } |
| 443 | |
| 444 | /* |
| 445 | * Find the backwards transitive closure of the flow graph. These sets |
| 446 | * are backwards in the sense that we find the set of nodes that reach |
| 447 | * a given node, not the set of nodes that can be reached by a node. |
| 448 | * |
| 449 | * Assumes graph has been leveled. |
| 450 | */ |
| 451 | static void |
Elliott Hughes | 965a4b5 | 2017-05-15 10:37:39 -0700 | [diff] [blame] | 452 | find_closure(opt_state_t *opt_state, struct block *root) |
The Android Open Source Project | 478ab6c | 2009-03-03 19:30:05 -0800 | [diff] [blame] | 453 | { |
| 454 | int i; |
| 455 | struct block *b; |
| 456 | |
| 457 | /* |
| 458 | * Initialize sets to contain no nodes. |
| 459 | */ |
Elliott Hughes | 965a4b5 | 2017-05-15 10:37:39 -0700 | [diff] [blame] | 460 | memset((char *)opt_state->all_closure_sets, 0, |
| 461 | opt_state->n_blocks * opt_state->nodewords * sizeof(*opt_state->all_closure_sets)); |
The Android Open Source Project | 478ab6c | 2009-03-03 19:30:05 -0800 | [diff] [blame] | 462 | |
| 463 | /* root->level is the highest level no found. */ |
| 464 | for (i = root->level; i >= 0; --i) { |
Elliott Hughes | 965a4b5 | 2017-05-15 10:37:39 -0700 | [diff] [blame] | 465 | for (b = opt_state->levels[i]; b; b = b->link) { |
The Android Open Source Project | 478ab6c | 2009-03-03 19:30:05 -0800 | [diff] [blame] | 466 | SET_INSERT(b->closure, b->id); |
| 467 | if (JT(b) == 0) |
| 468 | continue; |
Elliott Hughes | 965a4b5 | 2017-05-15 10:37:39 -0700 | [diff] [blame] | 469 | SET_UNION(JT(b)->closure, b->closure, opt_state->nodewords); |
| 470 | SET_UNION(JF(b)->closure, b->closure, opt_state->nodewords); |
The Android Open Source Project | 478ab6c | 2009-03-03 19:30:05 -0800 | [diff] [blame] | 471 | } |
| 472 | } |
| 473 | } |
| 474 | |
| 475 | /* |
| 476 | * Return the register number that is used by s. If A and X are both |
| 477 | * used, return AX_ATOM. If no register is used, return -1. |
| 478 | * |
| 479 | * The implementation should probably change to an array access. |
| 480 | */ |
| 481 | static int |
JP Abgrall | 511eca3 | 2014-02-12 13:46:45 -0800 | [diff] [blame] | 482 | atomuse(struct stmt *s) |
The Android Open Source Project | 478ab6c | 2009-03-03 19:30:05 -0800 | [diff] [blame] | 483 | { |
| 484 | register int c = s->code; |
| 485 | |
| 486 | if (c == NOP) |
| 487 | return -1; |
| 488 | |
| 489 | switch (BPF_CLASS(c)) { |
| 490 | |
| 491 | case BPF_RET: |
| 492 | return (BPF_RVAL(c) == BPF_A) ? A_ATOM : |
| 493 | (BPF_RVAL(c) == BPF_X) ? X_ATOM : -1; |
| 494 | |
| 495 | case BPF_LD: |
| 496 | case BPF_LDX: |
| 497 | return (BPF_MODE(c) == BPF_IND) ? X_ATOM : |
| 498 | (BPF_MODE(c) == BPF_MEM) ? s->k : -1; |
| 499 | |
| 500 | case BPF_ST: |
| 501 | return A_ATOM; |
| 502 | |
| 503 | case BPF_STX: |
| 504 | return X_ATOM; |
| 505 | |
| 506 | case BPF_JMP: |
| 507 | case BPF_ALU: |
| 508 | if (BPF_SRC(c) == BPF_X) |
| 509 | return AX_ATOM; |
| 510 | return A_ATOM; |
| 511 | |
| 512 | case BPF_MISC: |
| 513 | return BPF_MISCOP(c) == BPF_TXA ? X_ATOM : A_ATOM; |
| 514 | } |
| 515 | abort(); |
| 516 | /* NOTREACHED */ |
| 517 | } |
| 518 | |
| 519 | /* |
| 520 | * Return the register number that is defined by 's'. We assume that |
| 521 | * a single stmt cannot define more than one register. If no register |
| 522 | * is defined, return -1. |
| 523 | * |
| 524 | * The implementation should probably change to an array access. |
| 525 | */ |
| 526 | static int |
JP Abgrall | 511eca3 | 2014-02-12 13:46:45 -0800 | [diff] [blame] | 527 | atomdef(struct stmt *s) |
The Android Open Source Project | 478ab6c | 2009-03-03 19:30:05 -0800 | [diff] [blame] | 528 | { |
| 529 | if (s->code == NOP) |
| 530 | return -1; |
| 531 | |
| 532 | switch (BPF_CLASS(s->code)) { |
| 533 | |
| 534 | case BPF_LD: |
| 535 | case BPF_ALU: |
| 536 | return A_ATOM; |
| 537 | |
| 538 | case BPF_LDX: |
| 539 | return X_ATOM; |
| 540 | |
| 541 | case BPF_ST: |
| 542 | case BPF_STX: |
| 543 | return s->k; |
| 544 | |
| 545 | case BPF_MISC: |
| 546 | return BPF_MISCOP(s->code) == BPF_TAX ? X_ATOM : A_ATOM; |
| 547 | } |
| 548 | return -1; |
| 549 | } |
| 550 | |
| 551 | /* |
| 552 | * Compute the sets of registers used, defined, and killed by 'b'. |
| 553 | * |
| 554 | * "Used" means that a statement in 'b' uses the register before any |
| 555 | * statement in 'b' defines it, i.e. it uses the value left in |
| 556 | * that register by a predecessor block of this block. |
| 557 | * "Defined" means that a statement in 'b' defines it. |
| 558 | * "Killed" means that a statement in 'b' defines it before any |
| 559 | * statement in 'b' uses it, i.e. it kills the value left in that |
| 560 | * register by a predecessor block of this block. |
| 561 | */ |
| 562 | static void |
JP Abgrall | 511eca3 | 2014-02-12 13:46:45 -0800 | [diff] [blame] | 563 | compute_local_ud(struct block *b) |
The Android Open Source Project | 478ab6c | 2009-03-03 19:30:05 -0800 | [diff] [blame] | 564 | { |
| 565 | struct slist *s; |
Elliott Hughes | 965a4b5 | 2017-05-15 10:37:39 -0700 | [diff] [blame] | 566 | atomset def = 0, use = 0, killed = 0; |
The Android Open Source Project | 478ab6c | 2009-03-03 19:30:05 -0800 | [diff] [blame] | 567 | int atom; |
| 568 | |
| 569 | for (s = b->stmts; s; s = s->next) { |
| 570 | if (s->s.code == NOP) |
| 571 | continue; |
| 572 | atom = atomuse(&s->s); |
| 573 | if (atom >= 0) { |
| 574 | if (atom == AX_ATOM) { |
| 575 | if (!ATOMELEM(def, X_ATOM)) |
| 576 | use |= ATOMMASK(X_ATOM); |
| 577 | if (!ATOMELEM(def, A_ATOM)) |
| 578 | use |= ATOMMASK(A_ATOM); |
| 579 | } |
| 580 | else if (atom < N_ATOMS) { |
| 581 | if (!ATOMELEM(def, atom)) |
| 582 | use |= ATOMMASK(atom); |
| 583 | } |
| 584 | else |
| 585 | abort(); |
| 586 | } |
| 587 | atom = atomdef(&s->s); |
| 588 | if (atom >= 0) { |
| 589 | if (!ATOMELEM(use, atom)) |
Elliott Hughes | 965a4b5 | 2017-05-15 10:37:39 -0700 | [diff] [blame] | 590 | killed |= ATOMMASK(atom); |
The Android Open Source Project | 478ab6c | 2009-03-03 19:30:05 -0800 | [diff] [blame] | 591 | def |= ATOMMASK(atom); |
| 592 | } |
| 593 | } |
| 594 | if (BPF_CLASS(b->s.code) == BPF_JMP) { |
| 595 | /* |
| 596 | * XXX - what about RET? |
| 597 | */ |
| 598 | atom = atomuse(&b->s); |
| 599 | if (atom >= 0) { |
| 600 | if (atom == AX_ATOM) { |
| 601 | if (!ATOMELEM(def, X_ATOM)) |
| 602 | use |= ATOMMASK(X_ATOM); |
| 603 | if (!ATOMELEM(def, A_ATOM)) |
| 604 | use |= ATOMMASK(A_ATOM); |
| 605 | } |
| 606 | else if (atom < N_ATOMS) { |
| 607 | if (!ATOMELEM(def, atom)) |
| 608 | use |= ATOMMASK(atom); |
| 609 | } |
| 610 | else |
| 611 | abort(); |
| 612 | } |
| 613 | } |
| 614 | |
| 615 | b->def = def; |
Elliott Hughes | 965a4b5 | 2017-05-15 10:37:39 -0700 | [diff] [blame] | 616 | b->kill = killed; |
The Android Open Source Project | 478ab6c | 2009-03-03 19:30:05 -0800 | [diff] [blame] | 617 | b->in_use = use; |
| 618 | } |
| 619 | |
| 620 | /* |
| 621 | * Assume graph is already leveled. |
| 622 | */ |
| 623 | static void |
Elliott Hughes | 965a4b5 | 2017-05-15 10:37:39 -0700 | [diff] [blame] | 624 | find_ud(opt_state_t *opt_state, struct block *root) |
The Android Open Source Project | 478ab6c | 2009-03-03 19:30:05 -0800 | [diff] [blame] | 625 | { |
| 626 | int i, maxlevel; |
| 627 | struct block *p; |
| 628 | |
| 629 | /* |
| 630 | * root->level is the highest level no found; |
| 631 | * count down from there. |
| 632 | */ |
| 633 | maxlevel = root->level; |
| 634 | for (i = maxlevel; i >= 0; --i) |
Elliott Hughes | 965a4b5 | 2017-05-15 10:37:39 -0700 | [diff] [blame] | 635 | for (p = opt_state->levels[i]; p; p = p->link) { |
The Android Open Source Project | 478ab6c | 2009-03-03 19:30:05 -0800 | [diff] [blame] | 636 | compute_local_ud(p); |
| 637 | p->out_use = 0; |
| 638 | } |
| 639 | |
| 640 | for (i = 1; i <= maxlevel; ++i) { |
Elliott Hughes | 965a4b5 | 2017-05-15 10:37:39 -0700 | [diff] [blame] | 641 | for (p = opt_state->levels[i]; p; p = p->link) { |
The Android Open Source Project | 478ab6c | 2009-03-03 19:30:05 -0800 | [diff] [blame] | 642 | p->out_use |= JT(p)->in_use | JF(p)->in_use; |
| 643 | p->in_use |= p->out_use &~ p->kill; |
| 644 | } |
| 645 | } |
| 646 | } |
The Android Open Source Project | 478ab6c | 2009-03-03 19:30:05 -0800 | [diff] [blame] | 647 | static void |
Elliott Hughes | 965a4b5 | 2017-05-15 10:37:39 -0700 | [diff] [blame] | 648 | init_val(opt_state_t *opt_state) |
The Android Open Source Project | 478ab6c | 2009-03-03 19:30:05 -0800 | [diff] [blame] | 649 | { |
Elliott Hughes | 965a4b5 | 2017-05-15 10:37:39 -0700 | [diff] [blame] | 650 | opt_state->curval = 0; |
| 651 | opt_state->next_vnode = opt_state->vnode_base; |
| 652 | memset((char *)opt_state->vmap, 0, opt_state->maxval * sizeof(*opt_state->vmap)); |
| 653 | memset((char *)opt_state->hashtbl, 0, sizeof opt_state->hashtbl); |
The Android Open Source Project | 478ab6c | 2009-03-03 19:30:05 -0800 | [diff] [blame] | 654 | } |
| 655 | |
| 656 | /* Because we really don't have an IR, this stuff is a little messy. */ |
| 657 | static int |
Elliott Hughes | 965a4b5 | 2017-05-15 10:37:39 -0700 | [diff] [blame] | 658 | F(opt_state_t *opt_state, int code, int v0, int v1) |
The Android Open Source Project | 478ab6c | 2009-03-03 19:30:05 -0800 | [diff] [blame] | 659 | { |
| 660 | u_int hash; |
| 661 | int val; |
| 662 | struct valnode *p; |
| 663 | |
Haibo Huang | 165065a | 2018-07-23 17:26:52 -0700 | [diff] [blame] | 664 | hash = (u_int)code ^ ((u_int)v0 << 4) ^ ((u_int)v1 << 8); |
The Android Open Source Project | 478ab6c | 2009-03-03 19:30:05 -0800 | [diff] [blame] | 665 | hash %= MODULUS; |
| 666 | |
Elliott Hughes | 965a4b5 | 2017-05-15 10:37:39 -0700 | [diff] [blame] | 667 | for (p = opt_state->hashtbl[hash]; p; p = p->next) |
The Android Open Source Project | 478ab6c | 2009-03-03 19:30:05 -0800 | [diff] [blame] | 668 | if (p->code == code && p->v0 == v0 && p->v1 == v1) |
| 669 | return p->val; |
| 670 | |
Elliott Hughes | 965a4b5 | 2017-05-15 10:37:39 -0700 | [diff] [blame] | 671 | val = ++opt_state->curval; |
The Android Open Source Project | 478ab6c | 2009-03-03 19:30:05 -0800 | [diff] [blame] | 672 | if (BPF_MODE(code) == BPF_IMM && |
| 673 | (BPF_CLASS(code) == BPF_LD || BPF_CLASS(code) == BPF_LDX)) { |
Elliott Hughes | 965a4b5 | 2017-05-15 10:37:39 -0700 | [diff] [blame] | 674 | opt_state->vmap[val].const_val = v0; |
| 675 | opt_state->vmap[val].is_const = 1; |
The Android Open Source Project | 478ab6c | 2009-03-03 19:30:05 -0800 | [diff] [blame] | 676 | } |
Elliott Hughes | 965a4b5 | 2017-05-15 10:37:39 -0700 | [diff] [blame] | 677 | p = opt_state->next_vnode++; |
The Android Open Source Project | 478ab6c | 2009-03-03 19:30:05 -0800 | [diff] [blame] | 678 | p->val = val; |
| 679 | p->code = code; |
| 680 | p->v0 = v0; |
| 681 | p->v1 = v1; |
Elliott Hughes | 965a4b5 | 2017-05-15 10:37:39 -0700 | [diff] [blame] | 682 | p->next = opt_state->hashtbl[hash]; |
| 683 | opt_state->hashtbl[hash] = p; |
The Android Open Source Project | 478ab6c | 2009-03-03 19:30:05 -0800 | [diff] [blame] | 684 | |
| 685 | return val; |
| 686 | } |
| 687 | |
| 688 | static inline void |
JP Abgrall | 511eca3 | 2014-02-12 13:46:45 -0800 | [diff] [blame] | 689 | vstore(struct stmt *s, int *valp, int newval, int alter) |
The Android Open Source Project | 478ab6c | 2009-03-03 19:30:05 -0800 | [diff] [blame] | 690 | { |
Haibo Huang | 165065a | 2018-07-23 17:26:52 -0700 | [diff] [blame] | 691 | if (alter && newval != VAL_UNKNOWN && *valp == newval) |
The Android Open Source Project | 478ab6c | 2009-03-03 19:30:05 -0800 | [diff] [blame] | 692 | s->code = NOP; |
| 693 | else |
| 694 | *valp = newval; |
| 695 | } |
| 696 | |
JP Abgrall | 511eca3 | 2014-02-12 13:46:45 -0800 | [diff] [blame] | 697 | /* |
| 698 | * Do constant-folding on binary operators. |
| 699 | * (Unary operators are handled elsewhere.) |
| 700 | */ |
The Android Open Source Project | 478ab6c | 2009-03-03 19:30:05 -0800 | [diff] [blame] | 701 | static void |
Haibo Huang | 165065a | 2018-07-23 17:26:52 -0700 | [diff] [blame] | 702 | fold_op(compiler_state_t *cstate, opt_state_t *opt_state, |
Elliott Hughes | 965a4b5 | 2017-05-15 10:37:39 -0700 | [diff] [blame] | 703 | struct stmt *s, int v0, int v1) |
The Android Open Source Project | 478ab6c | 2009-03-03 19:30:05 -0800 | [diff] [blame] | 704 | { |
| 705 | bpf_u_int32 a, b; |
| 706 | |
Elliott Hughes | 965a4b5 | 2017-05-15 10:37:39 -0700 | [diff] [blame] | 707 | a = opt_state->vmap[v0].const_val; |
| 708 | b = opt_state->vmap[v1].const_val; |
The Android Open Source Project | 478ab6c | 2009-03-03 19:30:05 -0800 | [diff] [blame] | 709 | |
| 710 | switch (BPF_OP(s->code)) { |
| 711 | case BPF_ADD: |
| 712 | a += b; |
| 713 | break; |
| 714 | |
| 715 | case BPF_SUB: |
| 716 | a -= b; |
| 717 | break; |
| 718 | |
| 719 | case BPF_MUL: |
| 720 | a *= b; |
| 721 | break; |
| 722 | |
| 723 | case BPF_DIV: |
| 724 | if (b == 0) |
Elliott Hughes | 965a4b5 | 2017-05-15 10:37:39 -0700 | [diff] [blame] | 725 | bpf_error(cstate, "division by zero"); |
The Android Open Source Project | 478ab6c | 2009-03-03 19:30:05 -0800 | [diff] [blame] | 726 | a /= b; |
| 727 | break; |
| 728 | |
Elliott Hughes | d8845d7 | 2015-10-19 18:07:04 -0700 | [diff] [blame] | 729 | case BPF_MOD: |
| 730 | if (b == 0) |
Elliott Hughes | 965a4b5 | 2017-05-15 10:37:39 -0700 | [diff] [blame] | 731 | bpf_error(cstate, "modulus by zero"); |
Elliott Hughes | d8845d7 | 2015-10-19 18:07:04 -0700 | [diff] [blame] | 732 | a %= b; |
| 733 | break; |
| 734 | |
The Android Open Source Project | 478ab6c | 2009-03-03 19:30:05 -0800 | [diff] [blame] | 735 | case BPF_AND: |
| 736 | a &= b; |
| 737 | break; |
| 738 | |
| 739 | case BPF_OR: |
| 740 | a |= b; |
| 741 | break; |
| 742 | |
Elliott Hughes | d8845d7 | 2015-10-19 18:07:04 -0700 | [diff] [blame] | 743 | case BPF_XOR: |
| 744 | a ^= b; |
| 745 | break; |
| 746 | |
The Android Open Source Project | 478ab6c | 2009-03-03 19:30:05 -0800 | [diff] [blame] | 747 | case BPF_LSH: |
| 748 | a <<= b; |
| 749 | break; |
| 750 | |
| 751 | case BPF_RSH: |
| 752 | a >>= b; |
| 753 | break; |
| 754 | |
The Android Open Source Project | 478ab6c | 2009-03-03 19:30:05 -0800 | [diff] [blame] | 755 | default: |
| 756 | abort(); |
| 757 | } |
| 758 | s->k = a; |
| 759 | s->code = BPF_LD|BPF_IMM; |
Elliott Hughes | 965a4b5 | 2017-05-15 10:37:39 -0700 | [diff] [blame] | 760 | opt_state->done = 0; |
The Android Open Source Project | 478ab6c | 2009-03-03 19:30:05 -0800 | [diff] [blame] | 761 | } |
| 762 | |
| 763 | static inline struct slist * |
JP Abgrall | 511eca3 | 2014-02-12 13:46:45 -0800 | [diff] [blame] | 764 | this_op(struct slist *s) |
The Android Open Source Project | 478ab6c | 2009-03-03 19:30:05 -0800 | [diff] [blame] | 765 | { |
| 766 | while (s != 0 && s->s.code == NOP) |
| 767 | s = s->next; |
| 768 | return s; |
| 769 | } |
| 770 | |
| 771 | static void |
JP Abgrall | 511eca3 | 2014-02-12 13:46:45 -0800 | [diff] [blame] | 772 | opt_not(struct block *b) |
The Android Open Source Project | 478ab6c | 2009-03-03 19:30:05 -0800 | [diff] [blame] | 773 | { |
| 774 | struct block *tmp = JT(b); |
| 775 | |
| 776 | JT(b) = JF(b); |
| 777 | JF(b) = tmp; |
| 778 | } |
| 779 | |
| 780 | static void |
Elliott Hughes | 965a4b5 | 2017-05-15 10:37:39 -0700 | [diff] [blame] | 781 | opt_peep(opt_state_t *opt_state, struct block *b) |
The Android Open Source Project | 478ab6c | 2009-03-03 19:30:05 -0800 | [diff] [blame] | 782 | { |
| 783 | struct slist *s; |
| 784 | struct slist *next, *last; |
| 785 | int val; |
| 786 | |
| 787 | s = b->stmts; |
| 788 | if (s == 0) |
| 789 | return; |
| 790 | |
| 791 | last = s; |
| 792 | for (/*empty*/; /*empty*/; s = next) { |
| 793 | /* |
| 794 | * Skip over nops. |
| 795 | */ |
| 796 | s = this_op(s); |
| 797 | if (s == 0) |
| 798 | break; /* nothing left in the block */ |
| 799 | |
| 800 | /* |
| 801 | * Find the next real instruction after that one |
| 802 | * (skipping nops). |
| 803 | */ |
| 804 | next = this_op(s->next); |
| 805 | if (next == 0) |
| 806 | break; /* no next instruction */ |
| 807 | last = next; |
| 808 | |
| 809 | /* |
| 810 | * st M[k] --> st M[k] |
| 811 | * ldx M[k] tax |
| 812 | */ |
| 813 | if (s->s.code == BPF_ST && |
| 814 | next->s.code == (BPF_LDX|BPF_MEM) && |
| 815 | s->s.k == next->s.k) { |
Elliott Hughes | 965a4b5 | 2017-05-15 10:37:39 -0700 | [diff] [blame] | 816 | opt_state->done = 0; |
The Android Open Source Project | 478ab6c | 2009-03-03 19:30:05 -0800 | [diff] [blame] | 817 | next->s.code = BPF_MISC|BPF_TAX; |
| 818 | } |
| 819 | /* |
| 820 | * ld #k --> ldx #k |
| 821 | * tax txa |
| 822 | */ |
| 823 | if (s->s.code == (BPF_LD|BPF_IMM) && |
| 824 | next->s.code == (BPF_MISC|BPF_TAX)) { |
| 825 | s->s.code = BPF_LDX|BPF_IMM; |
| 826 | next->s.code = BPF_MISC|BPF_TXA; |
Elliott Hughes | 965a4b5 | 2017-05-15 10:37:39 -0700 | [diff] [blame] | 827 | opt_state->done = 0; |
The Android Open Source Project | 478ab6c | 2009-03-03 19:30:05 -0800 | [diff] [blame] | 828 | } |
| 829 | /* |
| 830 | * This is an ugly special case, but it happens |
| 831 | * when you say tcp[k] or udp[k] where k is a constant. |
| 832 | */ |
| 833 | if (s->s.code == (BPF_LD|BPF_IMM)) { |
| 834 | struct slist *add, *tax, *ild; |
| 835 | |
| 836 | /* |
| 837 | * Check that X isn't used on exit from this |
| 838 | * block (which the optimizer might cause). |
| 839 | * We know the code generator won't generate |
| 840 | * any local dependencies. |
| 841 | */ |
| 842 | if (ATOMELEM(b->out_use, X_ATOM)) |
| 843 | continue; |
| 844 | |
| 845 | /* |
| 846 | * Check that the instruction following the ldi |
| 847 | * is an addx, or it's an ldxms with an addx |
| 848 | * following it (with 0 or more nops between the |
| 849 | * ldxms and addx). |
| 850 | */ |
| 851 | if (next->s.code != (BPF_LDX|BPF_MSH|BPF_B)) |
| 852 | add = next; |
| 853 | else |
| 854 | add = this_op(next->next); |
| 855 | if (add == 0 || add->s.code != (BPF_ALU|BPF_ADD|BPF_X)) |
| 856 | continue; |
| 857 | |
| 858 | /* |
| 859 | * Check that a tax follows that (with 0 or more |
| 860 | * nops between them). |
| 861 | */ |
| 862 | tax = this_op(add->next); |
| 863 | if (tax == 0 || tax->s.code != (BPF_MISC|BPF_TAX)) |
| 864 | continue; |
| 865 | |
| 866 | /* |
| 867 | * Check that an ild follows that (with 0 or more |
| 868 | * nops between them). |
| 869 | */ |
| 870 | ild = this_op(tax->next); |
| 871 | if (ild == 0 || BPF_CLASS(ild->s.code) != BPF_LD || |
| 872 | BPF_MODE(ild->s.code) != BPF_IND) |
| 873 | continue; |
| 874 | /* |
| 875 | * We want to turn this sequence: |
| 876 | * |
| 877 | * (004) ldi #0x2 {s} |
| 878 | * (005) ldxms [14] {next} -- optional |
| 879 | * (006) addx {add} |
| 880 | * (007) tax {tax} |
| 881 | * (008) ild [x+0] {ild} |
| 882 | * |
| 883 | * into this sequence: |
| 884 | * |
| 885 | * (004) nop |
| 886 | * (005) ldxms [14] |
| 887 | * (006) nop |
| 888 | * (007) nop |
| 889 | * (008) ild [x+2] |
| 890 | * |
| 891 | * XXX We need to check that X is not |
| 892 | * subsequently used, because we want to change |
| 893 | * what'll be in it after this sequence. |
| 894 | * |
| 895 | * We know we can eliminate the accumulator |
| 896 | * modifications earlier in the sequence since |
| 897 | * it is defined by the last stmt of this sequence |
| 898 | * (i.e., the last statement of the sequence loads |
| 899 | * a value into the accumulator, so we can eliminate |
| 900 | * earlier operations on the accumulator). |
| 901 | */ |
| 902 | ild->s.k += s->s.k; |
| 903 | s->s.code = NOP; |
| 904 | add->s.code = NOP; |
| 905 | tax->s.code = NOP; |
Elliott Hughes | 965a4b5 | 2017-05-15 10:37:39 -0700 | [diff] [blame] | 906 | opt_state->done = 0; |
The Android Open Source Project | 478ab6c | 2009-03-03 19:30:05 -0800 | [diff] [blame] | 907 | } |
| 908 | } |
| 909 | /* |
| 910 | * If the comparison at the end of a block is an equality |
| 911 | * comparison against a constant, and nobody uses the value |
| 912 | * we leave in the A register at the end of a block, and |
| 913 | * the operation preceding the comparison is an arithmetic |
| 914 | * operation, we can sometime optimize it away. |
| 915 | */ |
| 916 | if (b->s.code == (BPF_JMP|BPF_JEQ|BPF_K) && |
| 917 | !ATOMELEM(b->out_use, A_ATOM)) { |
| 918 | /* |
| 919 | * We can optimize away certain subtractions of the |
| 920 | * X register. |
| 921 | */ |
| 922 | if (last->s.code == (BPF_ALU|BPF_SUB|BPF_X)) { |
| 923 | val = b->val[X_ATOM]; |
Elliott Hughes | 965a4b5 | 2017-05-15 10:37:39 -0700 | [diff] [blame] | 924 | if (opt_state->vmap[val].is_const) { |
The Android Open Source Project | 478ab6c | 2009-03-03 19:30:05 -0800 | [diff] [blame] | 925 | /* |
| 926 | * If we have a subtract to do a comparison, |
| 927 | * and the X register is a known constant, |
| 928 | * we can merge this value into the |
| 929 | * comparison: |
| 930 | * |
| 931 | * sub x -> nop |
| 932 | * jeq #y jeq #(x+y) |
| 933 | */ |
Elliott Hughes | 965a4b5 | 2017-05-15 10:37:39 -0700 | [diff] [blame] | 934 | b->s.k += opt_state->vmap[val].const_val; |
The Android Open Source Project | 478ab6c | 2009-03-03 19:30:05 -0800 | [diff] [blame] | 935 | last->s.code = NOP; |
Elliott Hughes | 965a4b5 | 2017-05-15 10:37:39 -0700 | [diff] [blame] | 936 | opt_state->done = 0; |
The Android Open Source Project | 478ab6c | 2009-03-03 19:30:05 -0800 | [diff] [blame] | 937 | } else if (b->s.k == 0) { |
| 938 | /* |
| 939 | * If the X register isn't a constant, |
| 940 | * and the comparison in the test is |
| 941 | * against 0, we can compare with the |
| 942 | * X register, instead: |
| 943 | * |
| 944 | * sub x -> nop |
| 945 | * jeq #0 jeq x |
| 946 | */ |
| 947 | last->s.code = NOP; |
| 948 | b->s.code = BPF_JMP|BPF_JEQ|BPF_X; |
Elliott Hughes | 965a4b5 | 2017-05-15 10:37:39 -0700 | [diff] [blame] | 949 | opt_state->done = 0; |
The Android Open Source Project | 478ab6c | 2009-03-03 19:30:05 -0800 | [diff] [blame] | 950 | } |
| 951 | } |
| 952 | /* |
| 953 | * Likewise, a constant subtract can be simplified: |
| 954 | * |
| 955 | * sub #x -> nop |
| 956 | * jeq #y -> jeq #(x+y) |
| 957 | */ |
| 958 | else if (last->s.code == (BPF_ALU|BPF_SUB|BPF_K)) { |
| 959 | last->s.code = NOP; |
| 960 | b->s.k += last->s.k; |
Elliott Hughes | 965a4b5 | 2017-05-15 10:37:39 -0700 | [diff] [blame] | 961 | opt_state->done = 0; |
The Android Open Source Project | 478ab6c | 2009-03-03 19:30:05 -0800 | [diff] [blame] | 962 | } |
| 963 | /* |
| 964 | * And, similarly, a constant AND can be simplified |
| 965 | * if we're testing against 0, i.e.: |
| 966 | * |
| 967 | * and #k nop |
| 968 | * jeq #0 -> jset #k |
| 969 | */ |
| 970 | else if (last->s.code == (BPF_ALU|BPF_AND|BPF_K) && |
| 971 | b->s.k == 0) { |
| 972 | b->s.k = last->s.k; |
| 973 | b->s.code = BPF_JMP|BPF_K|BPF_JSET; |
| 974 | last->s.code = NOP; |
Elliott Hughes | 965a4b5 | 2017-05-15 10:37:39 -0700 | [diff] [blame] | 975 | opt_state->done = 0; |
The Android Open Source Project | 478ab6c | 2009-03-03 19:30:05 -0800 | [diff] [blame] | 976 | opt_not(b); |
| 977 | } |
| 978 | } |
| 979 | /* |
| 980 | * jset #0 -> never |
| 981 | * jset #ffffffff -> always |
| 982 | */ |
| 983 | if (b->s.code == (BPF_JMP|BPF_K|BPF_JSET)) { |
| 984 | if (b->s.k == 0) |
| 985 | JT(b) = JF(b); |
Elliott Hughes | 965a4b5 | 2017-05-15 10:37:39 -0700 | [diff] [blame] | 986 | if ((u_int)b->s.k == 0xffffffffU) |
The Android Open Source Project | 478ab6c | 2009-03-03 19:30:05 -0800 | [diff] [blame] | 987 | JF(b) = JT(b); |
| 988 | } |
| 989 | /* |
JP Abgrall | 511eca3 | 2014-02-12 13:46:45 -0800 | [diff] [blame] | 990 | * If we're comparing against the index register, and the index |
| 991 | * register is a known constant, we can just compare against that |
| 992 | * constant. |
| 993 | */ |
| 994 | val = b->val[X_ATOM]; |
Elliott Hughes | 965a4b5 | 2017-05-15 10:37:39 -0700 | [diff] [blame] | 995 | if (opt_state->vmap[val].is_const && BPF_SRC(b->s.code) == BPF_X) { |
| 996 | bpf_int32 v = opt_state->vmap[val].const_val; |
JP Abgrall | 511eca3 | 2014-02-12 13:46:45 -0800 | [diff] [blame] | 997 | b->s.code &= ~BPF_X; |
| 998 | b->s.k = v; |
| 999 | } |
| 1000 | /* |
The Android Open Source Project | 478ab6c | 2009-03-03 19:30:05 -0800 | [diff] [blame] | 1001 | * If the accumulator is a known constant, we can compute the |
| 1002 | * comparison result. |
| 1003 | */ |
| 1004 | val = b->val[A_ATOM]; |
Elliott Hughes | 965a4b5 | 2017-05-15 10:37:39 -0700 | [diff] [blame] | 1005 | if (opt_state->vmap[val].is_const && BPF_SRC(b->s.code) == BPF_K) { |
| 1006 | bpf_int32 v = opt_state->vmap[val].const_val; |
The Android Open Source Project | 478ab6c | 2009-03-03 19:30:05 -0800 | [diff] [blame] | 1007 | switch (BPF_OP(b->s.code)) { |
| 1008 | |
| 1009 | case BPF_JEQ: |
| 1010 | v = v == b->s.k; |
| 1011 | break; |
| 1012 | |
| 1013 | case BPF_JGT: |
Elliott Hughes | 965a4b5 | 2017-05-15 10:37:39 -0700 | [diff] [blame] | 1014 | v = (unsigned)v > (unsigned)b->s.k; |
The Android Open Source Project | 478ab6c | 2009-03-03 19:30:05 -0800 | [diff] [blame] | 1015 | break; |
| 1016 | |
| 1017 | case BPF_JGE: |
Elliott Hughes | 965a4b5 | 2017-05-15 10:37:39 -0700 | [diff] [blame] | 1018 | v = (unsigned)v >= (unsigned)b->s.k; |
The Android Open Source Project | 478ab6c | 2009-03-03 19:30:05 -0800 | [diff] [blame] | 1019 | break; |
| 1020 | |
| 1021 | case BPF_JSET: |
| 1022 | v &= b->s.k; |
| 1023 | break; |
| 1024 | |
| 1025 | default: |
| 1026 | abort(); |
| 1027 | } |
| 1028 | if (JF(b) != JT(b)) |
Elliott Hughes | 965a4b5 | 2017-05-15 10:37:39 -0700 | [diff] [blame] | 1029 | opt_state->done = 0; |
The Android Open Source Project | 478ab6c | 2009-03-03 19:30:05 -0800 | [diff] [blame] | 1030 | if (v) |
| 1031 | JF(b) = JT(b); |
| 1032 | else |
| 1033 | JT(b) = JF(b); |
| 1034 | } |
| 1035 | } |
| 1036 | |
| 1037 | /* |
| 1038 | * Compute the symbolic value of expression of 's', and update |
| 1039 | * anything it defines in the value table 'val'. If 'alter' is true, |
| 1040 | * do various optimizations. This code would be cleaner if symbolic |
| 1041 | * evaluation and code transformations weren't folded together. |
| 1042 | */ |
| 1043 | static void |
Haibo Huang | 165065a | 2018-07-23 17:26:52 -0700 | [diff] [blame] | 1044 | opt_stmt(compiler_state_t *cstate, opt_state_t *opt_state, |
Elliott Hughes | 965a4b5 | 2017-05-15 10:37:39 -0700 | [diff] [blame] | 1045 | struct stmt *s, int val[], int alter) |
The Android Open Source Project | 478ab6c | 2009-03-03 19:30:05 -0800 | [diff] [blame] | 1046 | { |
| 1047 | int op; |
| 1048 | int v; |
| 1049 | |
| 1050 | switch (s->code) { |
| 1051 | |
| 1052 | case BPF_LD|BPF_ABS|BPF_W: |
| 1053 | case BPF_LD|BPF_ABS|BPF_H: |
| 1054 | case BPF_LD|BPF_ABS|BPF_B: |
Elliott Hughes | 965a4b5 | 2017-05-15 10:37:39 -0700 | [diff] [blame] | 1055 | v = F(opt_state, s->code, s->k, 0L); |
The Android Open Source Project | 478ab6c | 2009-03-03 19:30:05 -0800 | [diff] [blame] | 1056 | vstore(s, &val[A_ATOM], v, alter); |
| 1057 | break; |
| 1058 | |
| 1059 | case BPF_LD|BPF_IND|BPF_W: |
| 1060 | case BPF_LD|BPF_IND|BPF_H: |
| 1061 | case BPF_LD|BPF_IND|BPF_B: |
| 1062 | v = val[X_ATOM]; |
Elliott Hughes | 965a4b5 | 2017-05-15 10:37:39 -0700 | [diff] [blame] | 1063 | if (alter && opt_state->vmap[v].is_const) { |
The Android Open Source Project | 478ab6c | 2009-03-03 19:30:05 -0800 | [diff] [blame] | 1064 | s->code = BPF_LD|BPF_ABS|BPF_SIZE(s->code); |
Elliott Hughes | 965a4b5 | 2017-05-15 10:37:39 -0700 | [diff] [blame] | 1065 | s->k += opt_state->vmap[v].const_val; |
| 1066 | v = F(opt_state, s->code, s->k, 0L); |
| 1067 | opt_state->done = 0; |
The Android Open Source Project | 478ab6c | 2009-03-03 19:30:05 -0800 | [diff] [blame] | 1068 | } |
| 1069 | else |
Elliott Hughes | 965a4b5 | 2017-05-15 10:37:39 -0700 | [diff] [blame] | 1070 | v = F(opt_state, s->code, s->k, v); |
The Android Open Source Project | 478ab6c | 2009-03-03 19:30:05 -0800 | [diff] [blame] | 1071 | vstore(s, &val[A_ATOM], v, alter); |
| 1072 | break; |
| 1073 | |
| 1074 | case BPF_LD|BPF_LEN: |
Elliott Hughes | 965a4b5 | 2017-05-15 10:37:39 -0700 | [diff] [blame] | 1075 | v = F(opt_state, s->code, 0L, 0L); |
The Android Open Source Project | 478ab6c | 2009-03-03 19:30:05 -0800 | [diff] [blame] | 1076 | vstore(s, &val[A_ATOM], v, alter); |
| 1077 | break; |
| 1078 | |
| 1079 | case BPF_LD|BPF_IMM: |
| 1080 | v = K(s->k); |
| 1081 | vstore(s, &val[A_ATOM], v, alter); |
| 1082 | break; |
| 1083 | |
| 1084 | case BPF_LDX|BPF_IMM: |
| 1085 | v = K(s->k); |
| 1086 | vstore(s, &val[X_ATOM], v, alter); |
| 1087 | break; |
| 1088 | |
| 1089 | case BPF_LDX|BPF_MSH|BPF_B: |
Elliott Hughes | 965a4b5 | 2017-05-15 10:37:39 -0700 | [diff] [blame] | 1090 | v = F(opt_state, s->code, s->k, 0L); |
The Android Open Source Project | 478ab6c | 2009-03-03 19:30:05 -0800 | [diff] [blame] | 1091 | vstore(s, &val[X_ATOM], v, alter); |
| 1092 | break; |
| 1093 | |
| 1094 | case BPF_ALU|BPF_NEG: |
Elliott Hughes | 965a4b5 | 2017-05-15 10:37:39 -0700 | [diff] [blame] | 1095 | if (alter && opt_state->vmap[val[A_ATOM]].is_const) { |
The Android Open Source Project | 478ab6c | 2009-03-03 19:30:05 -0800 | [diff] [blame] | 1096 | s->code = BPF_LD|BPF_IMM; |
Elliott Hughes | 965a4b5 | 2017-05-15 10:37:39 -0700 | [diff] [blame] | 1097 | s->k = -opt_state->vmap[val[A_ATOM]].const_val; |
The Android Open Source Project | 478ab6c | 2009-03-03 19:30:05 -0800 | [diff] [blame] | 1098 | val[A_ATOM] = K(s->k); |
| 1099 | } |
| 1100 | else |
Elliott Hughes | 965a4b5 | 2017-05-15 10:37:39 -0700 | [diff] [blame] | 1101 | val[A_ATOM] = F(opt_state, s->code, val[A_ATOM], 0L); |
The Android Open Source Project | 478ab6c | 2009-03-03 19:30:05 -0800 | [diff] [blame] | 1102 | break; |
| 1103 | |
| 1104 | case BPF_ALU|BPF_ADD|BPF_K: |
| 1105 | case BPF_ALU|BPF_SUB|BPF_K: |
| 1106 | case BPF_ALU|BPF_MUL|BPF_K: |
| 1107 | case BPF_ALU|BPF_DIV|BPF_K: |
Elliott Hughes | d8845d7 | 2015-10-19 18:07:04 -0700 | [diff] [blame] | 1108 | case BPF_ALU|BPF_MOD|BPF_K: |
The Android Open Source Project | 478ab6c | 2009-03-03 19:30:05 -0800 | [diff] [blame] | 1109 | case BPF_ALU|BPF_AND|BPF_K: |
| 1110 | case BPF_ALU|BPF_OR|BPF_K: |
Elliott Hughes | d8845d7 | 2015-10-19 18:07:04 -0700 | [diff] [blame] | 1111 | case BPF_ALU|BPF_XOR|BPF_K: |
The Android Open Source Project | 478ab6c | 2009-03-03 19:30:05 -0800 | [diff] [blame] | 1112 | case BPF_ALU|BPF_LSH|BPF_K: |
| 1113 | case BPF_ALU|BPF_RSH|BPF_K: |
| 1114 | op = BPF_OP(s->code); |
| 1115 | if (alter) { |
| 1116 | if (s->k == 0) { |
| 1117 | /* don't optimize away "sub #0" |
| 1118 | * as it may be needed later to |
| 1119 | * fixup the generated math code */ |
| 1120 | if (op == BPF_ADD || |
| 1121 | op == BPF_LSH || op == BPF_RSH || |
Elliott Hughes | d8845d7 | 2015-10-19 18:07:04 -0700 | [diff] [blame] | 1122 | op == BPF_OR || op == BPF_XOR) { |
The Android Open Source Project | 478ab6c | 2009-03-03 19:30:05 -0800 | [diff] [blame] | 1123 | s->code = NOP; |
| 1124 | break; |
| 1125 | } |
| 1126 | if (op == BPF_MUL || op == BPF_AND) { |
| 1127 | s->code = BPF_LD|BPF_IMM; |
| 1128 | val[A_ATOM] = K(s->k); |
| 1129 | break; |
| 1130 | } |
| 1131 | } |
Elliott Hughes | 965a4b5 | 2017-05-15 10:37:39 -0700 | [diff] [blame] | 1132 | if (opt_state->vmap[val[A_ATOM]].is_const) { |
Haibo Huang | 165065a | 2018-07-23 17:26:52 -0700 | [diff] [blame] | 1133 | fold_op(cstate, opt_state, s, val[A_ATOM], K(s->k)); |
The Android Open Source Project | 478ab6c | 2009-03-03 19:30:05 -0800 | [diff] [blame] | 1134 | val[A_ATOM] = K(s->k); |
| 1135 | break; |
| 1136 | } |
| 1137 | } |
Elliott Hughes | 965a4b5 | 2017-05-15 10:37:39 -0700 | [diff] [blame] | 1138 | val[A_ATOM] = F(opt_state, s->code, val[A_ATOM], K(s->k)); |
The Android Open Source Project | 478ab6c | 2009-03-03 19:30:05 -0800 | [diff] [blame] | 1139 | break; |
| 1140 | |
| 1141 | case BPF_ALU|BPF_ADD|BPF_X: |
| 1142 | case BPF_ALU|BPF_SUB|BPF_X: |
| 1143 | case BPF_ALU|BPF_MUL|BPF_X: |
| 1144 | case BPF_ALU|BPF_DIV|BPF_X: |
Elliott Hughes | d8845d7 | 2015-10-19 18:07:04 -0700 | [diff] [blame] | 1145 | case BPF_ALU|BPF_MOD|BPF_X: |
The Android Open Source Project | 478ab6c | 2009-03-03 19:30:05 -0800 | [diff] [blame] | 1146 | case BPF_ALU|BPF_AND|BPF_X: |
| 1147 | case BPF_ALU|BPF_OR|BPF_X: |
Elliott Hughes | d8845d7 | 2015-10-19 18:07:04 -0700 | [diff] [blame] | 1148 | case BPF_ALU|BPF_XOR|BPF_X: |
The Android Open Source Project | 478ab6c | 2009-03-03 19:30:05 -0800 | [diff] [blame] | 1149 | case BPF_ALU|BPF_LSH|BPF_X: |
| 1150 | case BPF_ALU|BPF_RSH|BPF_X: |
| 1151 | op = BPF_OP(s->code); |
Elliott Hughes | 965a4b5 | 2017-05-15 10:37:39 -0700 | [diff] [blame] | 1152 | if (alter && opt_state->vmap[val[X_ATOM]].is_const) { |
| 1153 | if (opt_state->vmap[val[A_ATOM]].is_const) { |
Haibo Huang | 165065a | 2018-07-23 17:26:52 -0700 | [diff] [blame] | 1154 | fold_op(cstate, opt_state, s, val[A_ATOM], val[X_ATOM]); |
The Android Open Source Project | 478ab6c | 2009-03-03 19:30:05 -0800 | [diff] [blame] | 1155 | val[A_ATOM] = K(s->k); |
| 1156 | } |
| 1157 | else { |
| 1158 | s->code = BPF_ALU|BPF_K|op; |
Elliott Hughes | 965a4b5 | 2017-05-15 10:37:39 -0700 | [diff] [blame] | 1159 | s->k = opt_state->vmap[val[X_ATOM]].const_val; |
| 1160 | opt_state->done = 0; |
The Android Open Source Project | 478ab6c | 2009-03-03 19:30:05 -0800 | [diff] [blame] | 1161 | val[A_ATOM] = |
Elliott Hughes | 965a4b5 | 2017-05-15 10:37:39 -0700 | [diff] [blame] | 1162 | F(opt_state, s->code, val[A_ATOM], K(s->k)); |
The Android Open Source Project | 478ab6c | 2009-03-03 19:30:05 -0800 | [diff] [blame] | 1163 | } |
| 1164 | break; |
| 1165 | } |
| 1166 | /* |
| 1167 | * Check if we're doing something to an accumulator |
| 1168 | * that is 0, and simplify. This may not seem like |
| 1169 | * much of a simplification but it could open up further |
| 1170 | * optimizations. |
| 1171 | * XXX We could also check for mul by 1, etc. |
| 1172 | */ |
Elliott Hughes | 965a4b5 | 2017-05-15 10:37:39 -0700 | [diff] [blame] | 1173 | if (alter && opt_state->vmap[val[A_ATOM]].is_const |
| 1174 | && opt_state->vmap[val[A_ATOM]].const_val == 0) { |
Elliott Hughes | d8845d7 | 2015-10-19 18:07:04 -0700 | [diff] [blame] | 1175 | if (op == BPF_ADD || op == BPF_OR || op == BPF_XOR) { |
The Android Open Source Project | 478ab6c | 2009-03-03 19:30:05 -0800 | [diff] [blame] | 1176 | s->code = BPF_MISC|BPF_TXA; |
| 1177 | vstore(s, &val[A_ATOM], val[X_ATOM], alter); |
| 1178 | break; |
| 1179 | } |
Elliott Hughes | d8845d7 | 2015-10-19 18:07:04 -0700 | [diff] [blame] | 1180 | else if (op == BPF_MUL || op == BPF_DIV || op == BPF_MOD || |
The Android Open Source Project | 478ab6c | 2009-03-03 19:30:05 -0800 | [diff] [blame] | 1181 | op == BPF_AND || op == BPF_LSH || op == BPF_RSH) { |
| 1182 | s->code = BPF_LD|BPF_IMM; |
| 1183 | s->k = 0; |
| 1184 | vstore(s, &val[A_ATOM], K(s->k), alter); |
| 1185 | break; |
| 1186 | } |
| 1187 | else if (op == BPF_NEG) { |
| 1188 | s->code = NOP; |
| 1189 | break; |
| 1190 | } |
| 1191 | } |
Elliott Hughes | 965a4b5 | 2017-05-15 10:37:39 -0700 | [diff] [blame] | 1192 | val[A_ATOM] = F(opt_state, s->code, val[A_ATOM], val[X_ATOM]); |
The Android Open Source Project | 478ab6c | 2009-03-03 19:30:05 -0800 | [diff] [blame] | 1193 | break; |
| 1194 | |
| 1195 | case BPF_MISC|BPF_TXA: |
| 1196 | vstore(s, &val[A_ATOM], val[X_ATOM], alter); |
| 1197 | break; |
| 1198 | |
| 1199 | case BPF_LD|BPF_MEM: |
| 1200 | v = val[s->k]; |
Elliott Hughes | 965a4b5 | 2017-05-15 10:37:39 -0700 | [diff] [blame] | 1201 | if (alter && opt_state->vmap[v].is_const) { |
The Android Open Source Project | 478ab6c | 2009-03-03 19:30:05 -0800 | [diff] [blame] | 1202 | s->code = BPF_LD|BPF_IMM; |
Elliott Hughes | 965a4b5 | 2017-05-15 10:37:39 -0700 | [diff] [blame] | 1203 | s->k = opt_state->vmap[v].const_val; |
| 1204 | opt_state->done = 0; |
The Android Open Source Project | 478ab6c | 2009-03-03 19:30:05 -0800 | [diff] [blame] | 1205 | } |
| 1206 | vstore(s, &val[A_ATOM], v, alter); |
| 1207 | break; |
| 1208 | |
| 1209 | case BPF_MISC|BPF_TAX: |
| 1210 | vstore(s, &val[X_ATOM], val[A_ATOM], alter); |
| 1211 | break; |
| 1212 | |
| 1213 | case BPF_LDX|BPF_MEM: |
| 1214 | v = val[s->k]; |
Elliott Hughes | 965a4b5 | 2017-05-15 10:37:39 -0700 | [diff] [blame] | 1215 | if (alter && opt_state->vmap[v].is_const) { |
The Android Open Source Project | 478ab6c | 2009-03-03 19:30:05 -0800 | [diff] [blame] | 1216 | s->code = BPF_LDX|BPF_IMM; |
Elliott Hughes | 965a4b5 | 2017-05-15 10:37:39 -0700 | [diff] [blame] | 1217 | s->k = opt_state->vmap[v].const_val; |
| 1218 | opt_state->done = 0; |
The Android Open Source Project | 478ab6c | 2009-03-03 19:30:05 -0800 | [diff] [blame] | 1219 | } |
| 1220 | vstore(s, &val[X_ATOM], v, alter); |
| 1221 | break; |
| 1222 | |
| 1223 | case BPF_ST: |
| 1224 | vstore(s, &val[s->k], val[A_ATOM], alter); |
| 1225 | break; |
| 1226 | |
| 1227 | case BPF_STX: |
| 1228 | vstore(s, &val[s->k], val[X_ATOM], alter); |
| 1229 | break; |
| 1230 | } |
| 1231 | } |
| 1232 | |
| 1233 | static void |
Elliott Hughes | 965a4b5 | 2017-05-15 10:37:39 -0700 | [diff] [blame] | 1234 | deadstmt(opt_state_t *opt_state, register struct stmt *s, register struct stmt *last[]) |
The Android Open Source Project | 478ab6c | 2009-03-03 19:30:05 -0800 | [diff] [blame] | 1235 | { |
| 1236 | register int atom; |
| 1237 | |
| 1238 | atom = atomuse(s); |
| 1239 | if (atom >= 0) { |
| 1240 | if (atom == AX_ATOM) { |
| 1241 | last[X_ATOM] = 0; |
| 1242 | last[A_ATOM] = 0; |
| 1243 | } |
| 1244 | else |
| 1245 | last[atom] = 0; |
| 1246 | } |
| 1247 | atom = atomdef(s); |
| 1248 | if (atom >= 0) { |
| 1249 | if (last[atom]) { |
Elliott Hughes | 965a4b5 | 2017-05-15 10:37:39 -0700 | [diff] [blame] | 1250 | opt_state->done = 0; |
The Android Open Source Project | 478ab6c | 2009-03-03 19:30:05 -0800 | [diff] [blame] | 1251 | last[atom]->code = NOP; |
| 1252 | } |
| 1253 | last[atom] = s; |
| 1254 | } |
| 1255 | } |
| 1256 | |
| 1257 | static void |
Elliott Hughes | 965a4b5 | 2017-05-15 10:37:39 -0700 | [diff] [blame] | 1258 | opt_deadstores(opt_state_t *opt_state, register struct block *b) |
The Android Open Source Project | 478ab6c | 2009-03-03 19:30:05 -0800 | [diff] [blame] | 1259 | { |
| 1260 | register struct slist *s; |
| 1261 | register int atom; |
| 1262 | struct stmt *last[N_ATOMS]; |
| 1263 | |
| 1264 | memset((char *)last, 0, sizeof last); |
| 1265 | |
| 1266 | for (s = b->stmts; s != 0; s = s->next) |
Elliott Hughes | 965a4b5 | 2017-05-15 10:37:39 -0700 | [diff] [blame] | 1267 | deadstmt(opt_state, &s->s, last); |
| 1268 | deadstmt(opt_state, &b->s, last); |
The Android Open Source Project | 478ab6c | 2009-03-03 19:30:05 -0800 | [diff] [blame] | 1269 | |
| 1270 | for (atom = 0; atom < N_ATOMS; ++atom) |
| 1271 | if (last[atom] && !ATOMELEM(b->out_use, atom)) { |
| 1272 | last[atom]->code = NOP; |
Elliott Hughes | 965a4b5 | 2017-05-15 10:37:39 -0700 | [diff] [blame] | 1273 | opt_state->done = 0; |
The Android Open Source Project | 478ab6c | 2009-03-03 19:30:05 -0800 | [diff] [blame] | 1274 | } |
| 1275 | } |
| 1276 | |
| 1277 | static void |
Haibo Huang | 165065a | 2018-07-23 17:26:52 -0700 | [diff] [blame] | 1278 | opt_blk(compiler_state_t *cstate, opt_state_t *opt_state, |
Elliott Hughes | 965a4b5 | 2017-05-15 10:37:39 -0700 | [diff] [blame] | 1279 | struct block *b, int do_stmts) |
The Android Open Source Project | 478ab6c | 2009-03-03 19:30:05 -0800 | [diff] [blame] | 1280 | { |
| 1281 | struct slist *s; |
| 1282 | struct edge *p; |
| 1283 | int i; |
| 1284 | bpf_int32 aval, xval; |
| 1285 | |
| 1286 | #if 0 |
| 1287 | for (s = b->stmts; s && s->next; s = s->next) |
| 1288 | if (BPF_CLASS(s->s.code) == BPF_JMP) { |
| 1289 | do_stmts = 0; |
| 1290 | break; |
| 1291 | } |
| 1292 | #endif |
| 1293 | |
| 1294 | /* |
| 1295 | * Initialize the atom values. |
| 1296 | */ |
| 1297 | p = b->in_edges; |
| 1298 | if (p == 0) { |
| 1299 | /* |
| 1300 | * We have no predecessors, so everything is undefined |
| 1301 | * upon entry to this block. |
| 1302 | */ |
| 1303 | memset((char *)b->val, 0, sizeof(b->val)); |
| 1304 | } else { |
| 1305 | /* |
| 1306 | * Inherit values from our predecessors. |
| 1307 | * |
| 1308 | * First, get the values from the predecessor along the |
| 1309 | * first edge leading to this node. |
| 1310 | */ |
| 1311 | memcpy((char *)b->val, (char *)p->pred->val, sizeof(b->val)); |
| 1312 | /* |
| 1313 | * Now look at all the other nodes leading to this node. |
| 1314 | * If, for the predecessor along that edge, a register |
| 1315 | * has a different value from the one we have (i.e., |
| 1316 | * control paths are merging, and the merging paths |
| 1317 | * assign different values to that register), give the |
| 1318 | * register the undefined value of 0. |
| 1319 | */ |
| 1320 | while ((p = p->next) != NULL) { |
| 1321 | for (i = 0; i < N_ATOMS; ++i) |
| 1322 | if (b->val[i] != p->pred->val[i]) |
| 1323 | b->val[i] = 0; |
| 1324 | } |
| 1325 | } |
| 1326 | aval = b->val[A_ATOM]; |
| 1327 | xval = b->val[X_ATOM]; |
| 1328 | for (s = b->stmts; s; s = s->next) |
Haibo Huang | 165065a | 2018-07-23 17:26:52 -0700 | [diff] [blame] | 1329 | opt_stmt(cstate, opt_state, &s->s, b->val, do_stmts); |
The Android Open Source Project | 478ab6c | 2009-03-03 19:30:05 -0800 | [diff] [blame] | 1330 | |
| 1331 | /* |
| 1332 | * This is a special case: if we don't use anything from this |
| 1333 | * block, and we load the accumulator or index register with a |
| 1334 | * value that is already there, or if this block is a return, |
| 1335 | * eliminate all the statements. |
| 1336 | * |
| 1337 | * XXX - what if it does a store? |
| 1338 | * |
| 1339 | * XXX - why does it matter whether we use anything from this |
| 1340 | * block? If the accumulator or index register doesn't change |
| 1341 | * its value, isn't that OK even if we use that value? |
| 1342 | * |
| 1343 | * XXX - if we load the accumulator with a different value, |
| 1344 | * and the block ends with a conditional branch, we obviously |
| 1345 | * can't eliminate it, as the branch depends on that value. |
| 1346 | * For the index register, the conditional branch only depends |
| 1347 | * on the index register value if the test is against the index |
| 1348 | * register value rather than a constant; if nothing uses the |
| 1349 | * value we put into the index register, and we're not testing |
| 1350 | * against the index register's value, and there aren't any |
| 1351 | * other problems that would keep us from eliminating this |
| 1352 | * block, can we eliminate it? |
| 1353 | */ |
| 1354 | if (do_stmts && |
Haibo Huang | 165065a | 2018-07-23 17:26:52 -0700 | [diff] [blame] | 1355 | ((b->out_use == 0 && |
| 1356 | aval != VAL_UNKNOWN && b->val[A_ATOM] == aval && |
| 1357 | xval != VAL_UNKNOWN && b->val[X_ATOM] == xval) || |
The Android Open Source Project | 478ab6c | 2009-03-03 19:30:05 -0800 | [diff] [blame] | 1358 | BPF_CLASS(b->s.code) == BPF_RET)) { |
| 1359 | if (b->stmts != 0) { |
| 1360 | b->stmts = 0; |
Elliott Hughes | 965a4b5 | 2017-05-15 10:37:39 -0700 | [diff] [blame] | 1361 | opt_state->done = 0; |
The Android Open Source Project | 478ab6c | 2009-03-03 19:30:05 -0800 | [diff] [blame] | 1362 | } |
| 1363 | } else { |
Elliott Hughes | 965a4b5 | 2017-05-15 10:37:39 -0700 | [diff] [blame] | 1364 | opt_peep(opt_state, b); |
| 1365 | opt_deadstores(opt_state, b); |
The Android Open Source Project | 478ab6c | 2009-03-03 19:30:05 -0800 | [diff] [blame] | 1366 | } |
| 1367 | /* |
| 1368 | * Set up values for branch optimizer. |
| 1369 | */ |
| 1370 | if (BPF_SRC(b->s.code) == BPF_K) |
| 1371 | b->oval = K(b->s.k); |
| 1372 | else |
| 1373 | b->oval = b->val[X_ATOM]; |
| 1374 | b->et.code = b->s.code; |
| 1375 | b->ef.code = -b->s.code; |
| 1376 | } |
| 1377 | |
| 1378 | /* |
| 1379 | * Return true if any register that is used on exit from 'succ', has |
| 1380 | * an exit value that is different from the corresponding exit value |
| 1381 | * from 'b'. |
| 1382 | */ |
| 1383 | static int |
JP Abgrall | 511eca3 | 2014-02-12 13:46:45 -0800 | [diff] [blame] | 1384 | use_conflict(struct block *b, struct block *succ) |
The Android Open Source Project | 478ab6c | 2009-03-03 19:30:05 -0800 | [diff] [blame] | 1385 | { |
| 1386 | int atom; |
| 1387 | atomset use = succ->out_use; |
| 1388 | |
| 1389 | if (use == 0) |
| 1390 | return 0; |
| 1391 | |
| 1392 | for (atom = 0; atom < N_ATOMS; ++atom) |
| 1393 | if (ATOMELEM(use, atom)) |
| 1394 | if (b->val[atom] != succ->val[atom]) |
| 1395 | return 1; |
| 1396 | return 0; |
| 1397 | } |
| 1398 | |
| 1399 | static struct block * |
JP Abgrall | 511eca3 | 2014-02-12 13:46:45 -0800 | [diff] [blame] | 1400 | fold_edge(struct block *child, struct edge *ep) |
The Android Open Source Project | 478ab6c | 2009-03-03 19:30:05 -0800 | [diff] [blame] | 1401 | { |
| 1402 | int sense; |
| 1403 | int aval0, aval1, oval0, oval1; |
| 1404 | int code = ep->code; |
| 1405 | |
| 1406 | if (code < 0) { |
| 1407 | code = -code; |
| 1408 | sense = 0; |
| 1409 | } else |
| 1410 | sense = 1; |
| 1411 | |
| 1412 | if (child->s.code != code) |
| 1413 | return 0; |
| 1414 | |
| 1415 | aval0 = child->val[A_ATOM]; |
| 1416 | oval0 = child->oval; |
| 1417 | aval1 = ep->pred->val[A_ATOM]; |
| 1418 | oval1 = ep->pred->oval; |
| 1419 | |
| 1420 | if (aval0 != aval1) |
| 1421 | return 0; |
| 1422 | |
| 1423 | if (oval0 == oval1) |
| 1424 | /* |
| 1425 | * The operands of the branch instructions are |
| 1426 | * identical, so the result is true if a true |
| 1427 | * branch was taken to get here, otherwise false. |
| 1428 | */ |
| 1429 | return sense ? JT(child) : JF(child); |
| 1430 | |
| 1431 | if (sense && code == (BPF_JMP|BPF_JEQ|BPF_K)) |
| 1432 | /* |
| 1433 | * At this point, we only know the comparison if we |
| 1434 | * came down the true branch, and it was an equality |
| 1435 | * comparison with a constant. |
| 1436 | * |
| 1437 | * I.e., if we came down the true branch, and the branch |
| 1438 | * was an equality comparison with a constant, we know the |
| 1439 | * accumulator contains that constant. If we came down |
| 1440 | * the false branch, or the comparison wasn't with a |
| 1441 | * constant, we don't know what was in the accumulator. |
| 1442 | * |
| 1443 | * We rely on the fact that distinct constants have distinct |
| 1444 | * value numbers. |
| 1445 | */ |
| 1446 | return JF(child); |
| 1447 | |
| 1448 | return 0; |
| 1449 | } |
| 1450 | |
The Android Open Source Project | 478ab6c | 2009-03-03 19:30:05 -0800 | [diff] [blame] | 1451 | static void |
Elliott Hughes | 965a4b5 | 2017-05-15 10:37:39 -0700 | [diff] [blame] | 1452 | opt_j(opt_state_t *opt_state, struct edge *ep) |
The Android Open Source Project | 478ab6c | 2009-03-03 19:30:05 -0800 | [diff] [blame] | 1453 | { |
| 1454 | register int i, k; |
| 1455 | register struct block *target; |
| 1456 | |
| 1457 | if (JT(ep->succ) == 0) |
| 1458 | return; |
| 1459 | |
| 1460 | if (JT(ep->succ) == JF(ep->succ)) { |
| 1461 | /* |
| 1462 | * Common branch targets can be eliminated, provided |
| 1463 | * there is no data dependency. |
| 1464 | */ |
| 1465 | if (!use_conflict(ep->pred, ep->succ->et.succ)) { |
Elliott Hughes | 965a4b5 | 2017-05-15 10:37:39 -0700 | [diff] [blame] | 1466 | opt_state->done = 0; |
The Android Open Source Project | 478ab6c | 2009-03-03 19:30:05 -0800 | [diff] [blame] | 1467 | ep->succ = JT(ep->succ); |
| 1468 | } |
| 1469 | } |
| 1470 | /* |
| 1471 | * For each edge dominator that matches the successor of this |
| 1472 | * edge, promote the edge successor to the its grandchild. |
| 1473 | * |
| 1474 | * XXX We violate the set abstraction here in favor a reasonably |
| 1475 | * efficient loop. |
| 1476 | */ |
| 1477 | top: |
Elliott Hughes | 965a4b5 | 2017-05-15 10:37:39 -0700 | [diff] [blame] | 1478 | for (i = 0; i < opt_state->edgewords; ++i) { |
The Android Open Source Project | 478ab6c | 2009-03-03 19:30:05 -0800 | [diff] [blame] | 1479 | register bpf_u_int32 x = ep->edom[i]; |
| 1480 | |
| 1481 | while (x != 0) { |
Haibo Huang | 165065a | 2018-07-23 17:26:52 -0700 | [diff] [blame] | 1482 | k = lowest_set_bit(x); |
The Android Open Source Project | 478ab6c | 2009-03-03 19:30:05 -0800 | [diff] [blame] | 1483 | x &=~ (1 << k); |
| 1484 | k += i * BITS_PER_WORD; |
| 1485 | |
Elliott Hughes | 965a4b5 | 2017-05-15 10:37:39 -0700 | [diff] [blame] | 1486 | target = fold_edge(ep->succ, opt_state->edges[k]); |
The Android Open Source Project | 478ab6c | 2009-03-03 19:30:05 -0800 | [diff] [blame] | 1487 | /* |
| 1488 | * Check that there is no data dependency between |
| 1489 | * nodes that will be violated if we move the edge. |
| 1490 | */ |
| 1491 | if (target != 0 && !use_conflict(ep->pred, target)) { |
Elliott Hughes | 965a4b5 | 2017-05-15 10:37:39 -0700 | [diff] [blame] | 1492 | opt_state->done = 0; |
The Android Open Source Project | 478ab6c | 2009-03-03 19:30:05 -0800 | [diff] [blame] | 1493 | ep->succ = target; |
| 1494 | if (JT(target) != 0) |
| 1495 | /* |
| 1496 | * Start over unless we hit a leaf. |
| 1497 | */ |
| 1498 | goto top; |
| 1499 | return; |
| 1500 | } |
| 1501 | } |
| 1502 | } |
| 1503 | } |
| 1504 | |
| 1505 | |
| 1506 | static void |
Elliott Hughes | 965a4b5 | 2017-05-15 10:37:39 -0700 | [diff] [blame] | 1507 | or_pullup(opt_state_t *opt_state, struct block *b) |
The Android Open Source Project | 478ab6c | 2009-03-03 19:30:05 -0800 | [diff] [blame] | 1508 | { |
| 1509 | int val, at_top; |
| 1510 | struct block *pull; |
| 1511 | struct block **diffp, **samep; |
| 1512 | struct edge *ep; |
| 1513 | |
| 1514 | ep = b->in_edges; |
| 1515 | if (ep == 0) |
| 1516 | return; |
| 1517 | |
| 1518 | /* |
| 1519 | * Make sure each predecessor loads the same value. |
| 1520 | * XXX why? |
| 1521 | */ |
| 1522 | val = ep->pred->val[A_ATOM]; |
| 1523 | for (ep = ep->next; ep != 0; ep = ep->next) |
| 1524 | if (val != ep->pred->val[A_ATOM]) |
| 1525 | return; |
| 1526 | |
| 1527 | if (JT(b->in_edges->pred) == b) |
| 1528 | diffp = &JT(b->in_edges->pred); |
| 1529 | else |
| 1530 | diffp = &JF(b->in_edges->pred); |
| 1531 | |
| 1532 | at_top = 1; |
Haibo Huang | 165065a | 2018-07-23 17:26:52 -0700 | [diff] [blame] | 1533 | for (;;) { |
The Android Open Source Project | 478ab6c | 2009-03-03 19:30:05 -0800 | [diff] [blame] | 1534 | if (*diffp == 0) |
| 1535 | return; |
| 1536 | |
| 1537 | if (JT(*diffp) != JT(b)) |
| 1538 | return; |
| 1539 | |
| 1540 | if (!SET_MEMBER((*diffp)->dom, b->id)) |
| 1541 | return; |
| 1542 | |
| 1543 | if ((*diffp)->val[A_ATOM] != val) |
| 1544 | break; |
| 1545 | |
| 1546 | diffp = &JF(*diffp); |
| 1547 | at_top = 0; |
| 1548 | } |
| 1549 | samep = &JF(*diffp); |
Haibo Huang | 165065a | 2018-07-23 17:26:52 -0700 | [diff] [blame] | 1550 | for (;;) { |
The Android Open Source Project | 478ab6c | 2009-03-03 19:30:05 -0800 | [diff] [blame] | 1551 | if (*samep == 0) |
| 1552 | return; |
| 1553 | |
| 1554 | if (JT(*samep) != JT(b)) |
| 1555 | return; |
| 1556 | |
| 1557 | if (!SET_MEMBER((*samep)->dom, b->id)) |
| 1558 | return; |
| 1559 | |
| 1560 | if ((*samep)->val[A_ATOM] == val) |
| 1561 | break; |
| 1562 | |
| 1563 | /* XXX Need to check that there are no data dependencies |
| 1564 | between dp0 and dp1. Currently, the code generator |
| 1565 | will not produce such dependencies. */ |
| 1566 | samep = &JF(*samep); |
| 1567 | } |
| 1568 | #ifdef notdef |
| 1569 | /* XXX This doesn't cover everything. */ |
| 1570 | for (i = 0; i < N_ATOMS; ++i) |
| 1571 | if ((*samep)->val[i] != pred->val[i]) |
| 1572 | return; |
| 1573 | #endif |
| 1574 | /* Pull up the node. */ |
| 1575 | pull = *samep; |
| 1576 | *samep = JF(pull); |
| 1577 | JF(pull) = *diffp; |
| 1578 | |
| 1579 | /* |
| 1580 | * At the top of the chain, each predecessor needs to point at the |
| 1581 | * pulled up node. Inside the chain, there is only one predecessor |
| 1582 | * to worry about. |
| 1583 | */ |
| 1584 | if (at_top) { |
| 1585 | for (ep = b->in_edges; ep != 0; ep = ep->next) { |
| 1586 | if (JT(ep->pred) == b) |
| 1587 | JT(ep->pred) = pull; |
| 1588 | else |
| 1589 | JF(ep->pred) = pull; |
| 1590 | } |
| 1591 | } |
| 1592 | else |
| 1593 | *diffp = pull; |
| 1594 | |
Elliott Hughes | 965a4b5 | 2017-05-15 10:37:39 -0700 | [diff] [blame] | 1595 | opt_state->done = 0; |
The Android Open Source Project | 478ab6c | 2009-03-03 19:30:05 -0800 | [diff] [blame] | 1596 | } |
| 1597 | |
| 1598 | static void |
Elliott Hughes | 965a4b5 | 2017-05-15 10:37:39 -0700 | [diff] [blame] | 1599 | and_pullup(opt_state_t *opt_state, struct block *b) |
The Android Open Source Project | 478ab6c | 2009-03-03 19:30:05 -0800 | [diff] [blame] | 1600 | { |
| 1601 | int val, at_top; |
| 1602 | struct block *pull; |
| 1603 | struct block **diffp, **samep; |
| 1604 | struct edge *ep; |
| 1605 | |
| 1606 | ep = b->in_edges; |
| 1607 | if (ep == 0) |
| 1608 | return; |
| 1609 | |
| 1610 | /* |
| 1611 | * Make sure each predecessor loads the same value. |
| 1612 | */ |
| 1613 | val = ep->pred->val[A_ATOM]; |
| 1614 | for (ep = ep->next; ep != 0; ep = ep->next) |
| 1615 | if (val != ep->pred->val[A_ATOM]) |
| 1616 | return; |
| 1617 | |
| 1618 | if (JT(b->in_edges->pred) == b) |
| 1619 | diffp = &JT(b->in_edges->pred); |
| 1620 | else |
| 1621 | diffp = &JF(b->in_edges->pred); |
| 1622 | |
| 1623 | at_top = 1; |
Haibo Huang | 165065a | 2018-07-23 17:26:52 -0700 | [diff] [blame] | 1624 | for (;;) { |
The Android Open Source Project | 478ab6c | 2009-03-03 19:30:05 -0800 | [diff] [blame] | 1625 | if (*diffp == 0) |
| 1626 | return; |
| 1627 | |
| 1628 | if (JF(*diffp) != JF(b)) |
| 1629 | return; |
| 1630 | |
| 1631 | if (!SET_MEMBER((*diffp)->dom, b->id)) |
| 1632 | return; |
| 1633 | |
| 1634 | if ((*diffp)->val[A_ATOM] != val) |
| 1635 | break; |
| 1636 | |
| 1637 | diffp = &JT(*diffp); |
| 1638 | at_top = 0; |
| 1639 | } |
| 1640 | samep = &JT(*diffp); |
Haibo Huang | 165065a | 2018-07-23 17:26:52 -0700 | [diff] [blame] | 1641 | for (;;) { |
The Android Open Source Project | 478ab6c | 2009-03-03 19:30:05 -0800 | [diff] [blame] | 1642 | if (*samep == 0) |
| 1643 | return; |
| 1644 | |
| 1645 | if (JF(*samep) != JF(b)) |
| 1646 | return; |
| 1647 | |
| 1648 | if (!SET_MEMBER((*samep)->dom, b->id)) |
| 1649 | return; |
| 1650 | |
| 1651 | if ((*samep)->val[A_ATOM] == val) |
| 1652 | break; |
| 1653 | |
| 1654 | /* XXX Need to check that there are no data dependencies |
| 1655 | between diffp and samep. Currently, the code generator |
| 1656 | will not produce such dependencies. */ |
| 1657 | samep = &JT(*samep); |
| 1658 | } |
| 1659 | #ifdef notdef |
| 1660 | /* XXX This doesn't cover everything. */ |
| 1661 | for (i = 0; i < N_ATOMS; ++i) |
| 1662 | if ((*samep)->val[i] != pred->val[i]) |
| 1663 | return; |
| 1664 | #endif |
| 1665 | /* Pull up the node. */ |
| 1666 | pull = *samep; |
| 1667 | *samep = JT(pull); |
| 1668 | JT(pull) = *diffp; |
| 1669 | |
| 1670 | /* |
| 1671 | * At the top of the chain, each predecessor needs to point at the |
| 1672 | * pulled up node. Inside the chain, there is only one predecessor |
| 1673 | * to worry about. |
| 1674 | */ |
| 1675 | if (at_top) { |
| 1676 | for (ep = b->in_edges; ep != 0; ep = ep->next) { |
| 1677 | if (JT(ep->pred) == b) |
| 1678 | JT(ep->pred) = pull; |
| 1679 | else |
| 1680 | JF(ep->pred) = pull; |
| 1681 | } |
| 1682 | } |
| 1683 | else |
| 1684 | *diffp = pull; |
| 1685 | |
Elliott Hughes | 965a4b5 | 2017-05-15 10:37:39 -0700 | [diff] [blame] | 1686 | opt_state->done = 0; |
The Android Open Source Project | 478ab6c | 2009-03-03 19:30:05 -0800 | [diff] [blame] | 1687 | } |
| 1688 | |
| 1689 | static void |
Elliott Hughes | 965a4b5 | 2017-05-15 10:37:39 -0700 | [diff] [blame] | 1690 | opt_blks(compiler_state_t *cstate, opt_state_t *opt_state, struct icode *ic, |
| 1691 | int do_stmts) |
The Android Open Source Project | 478ab6c | 2009-03-03 19:30:05 -0800 | [diff] [blame] | 1692 | { |
| 1693 | int i, maxlevel; |
| 1694 | struct block *p; |
| 1695 | |
Elliott Hughes | 965a4b5 | 2017-05-15 10:37:39 -0700 | [diff] [blame] | 1696 | init_val(opt_state); |
| 1697 | maxlevel = ic->root->level; |
The Android Open Source Project | 478ab6c | 2009-03-03 19:30:05 -0800 | [diff] [blame] | 1698 | |
Elliott Hughes | 965a4b5 | 2017-05-15 10:37:39 -0700 | [diff] [blame] | 1699 | find_inedges(opt_state, ic->root); |
The Android Open Source Project | 478ab6c | 2009-03-03 19:30:05 -0800 | [diff] [blame] | 1700 | for (i = maxlevel; i >= 0; --i) |
Elliott Hughes | 965a4b5 | 2017-05-15 10:37:39 -0700 | [diff] [blame] | 1701 | for (p = opt_state->levels[i]; p; p = p->link) |
Haibo Huang | 165065a | 2018-07-23 17:26:52 -0700 | [diff] [blame] | 1702 | opt_blk(cstate, opt_state, p, do_stmts); |
The Android Open Source Project | 478ab6c | 2009-03-03 19:30:05 -0800 | [diff] [blame] | 1703 | |
| 1704 | if (do_stmts) |
| 1705 | /* |
| 1706 | * No point trying to move branches; it can't possibly |
| 1707 | * make a difference at this point. |
| 1708 | */ |
| 1709 | return; |
| 1710 | |
| 1711 | for (i = 1; i <= maxlevel; ++i) { |
Elliott Hughes | 965a4b5 | 2017-05-15 10:37:39 -0700 | [diff] [blame] | 1712 | for (p = opt_state->levels[i]; p; p = p->link) { |
| 1713 | opt_j(opt_state, &p->et); |
| 1714 | opt_j(opt_state, &p->ef); |
The Android Open Source Project | 478ab6c | 2009-03-03 19:30:05 -0800 | [diff] [blame] | 1715 | } |
| 1716 | } |
| 1717 | |
Elliott Hughes | 965a4b5 | 2017-05-15 10:37:39 -0700 | [diff] [blame] | 1718 | find_inedges(opt_state, ic->root); |
The Android Open Source Project | 478ab6c | 2009-03-03 19:30:05 -0800 | [diff] [blame] | 1719 | for (i = 1; i <= maxlevel; ++i) { |
Elliott Hughes | 965a4b5 | 2017-05-15 10:37:39 -0700 | [diff] [blame] | 1720 | for (p = opt_state->levels[i]; p; p = p->link) { |
| 1721 | or_pullup(opt_state, p); |
| 1722 | and_pullup(opt_state, p); |
The Android Open Source Project | 478ab6c | 2009-03-03 19:30:05 -0800 | [diff] [blame] | 1723 | } |
| 1724 | } |
| 1725 | } |
| 1726 | |
| 1727 | static inline void |
JP Abgrall | 511eca3 | 2014-02-12 13:46:45 -0800 | [diff] [blame] | 1728 | link_inedge(struct edge *parent, struct block *child) |
The Android Open Source Project | 478ab6c | 2009-03-03 19:30:05 -0800 | [diff] [blame] | 1729 | { |
| 1730 | parent->next = child->in_edges; |
| 1731 | child->in_edges = parent; |
| 1732 | } |
| 1733 | |
| 1734 | static void |
Elliott Hughes | 965a4b5 | 2017-05-15 10:37:39 -0700 | [diff] [blame] | 1735 | find_inedges(opt_state_t *opt_state, struct block *root) |
The Android Open Source Project | 478ab6c | 2009-03-03 19:30:05 -0800 | [diff] [blame] | 1736 | { |
| 1737 | int i; |
| 1738 | struct block *b; |
| 1739 | |
Elliott Hughes | 965a4b5 | 2017-05-15 10:37:39 -0700 | [diff] [blame] | 1740 | for (i = 0; i < opt_state->n_blocks; ++i) |
| 1741 | opt_state->blocks[i]->in_edges = 0; |
The Android Open Source Project | 478ab6c | 2009-03-03 19:30:05 -0800 | [diff] [blame] | 1742 | |
| 1743 | /* |
| 1744 | * Traverse the graph, adding each edge to the predecessor |
| 1745 | * list of its successors. Skip the leaves (i.e. level 0). |
| 1746 | */ |
| 1747 | for (i = root->level; i > 0; --i) { |
Elliott Hughes | 965a4b5 | 2017-05-15 10:37:39 -0700 | [diff] [blame] | 1748 | for (b = opt_state->levels[i]; b != 0; b = b->link) { |
The Android Open Source Project | 478ab6c | 2009-03-03 19:30:05 -0800 | [diff] [blame] | 1749 | link_inedge(&b->et, JT(b)); |
| 1750 | link_inedge(&b->ef, JF(b)); |
| 1751 | } |
| 1752 | } |
| 1753 | } |
| 1754 | |
| 1755 | static void |
JP Abgrall | 511eca3 | 2014-02-12 13:46:45 -0800 | [diff] [blame] | 1756 | opt_root(struct block **b) |
The Android Open Source Project | 478ab6c | 2009-03-03 19:30:05 -0800 | [diff] [blame] | 1757 | { |
| 1758 | struct slist *tmp, *s; |
| 1759 | |
| 1760 | s = (*b)->stmts; |
| 1761 | (*b)->stmts = 0; |
| 1762 | while (BPF_CLASS((*b)->s.code) == BPF_JMP && JT(*b) == JF(*b)) |
| 1763 | *b = JT(*b); |
| 1764 | |
| 1765 | tmp = (*b)->stmts; |
| 1766 | if (tmp != 0) |
| 1767 | sappend(s, tmp); |
| 1768 | (*b)->stmts = s; |
| 1769 | |
| 1770 | /* |
| 1771 | * If the root node is a return, then there is no |
| 1772 | * point executing any statements (since the bpf machine |
| 1773 | * has no side effects). |
| 1774 | */ |
| 1775 | if (BPF_CLASS((*b)->s.code) == BPF_RET) |
| 1776 | (*b)->stmts = 0; |
| 1777 | } |
| 1778 | |
| 1779 | static void |
Elliott Hughes | 965a4b5 | 2017-05-15 10:37:39 -0700 | [diff] [blame] | 1780 | opt_loop(compiler_state_t *cstate, opt_state_t *opt_state, struct icode *ic, |
| 1781 | int do_stmts) |
The Android Open Source Project | 478ab6c | 2009-03-03 19:30:05 -0800 | [diff] [blame] | 1782 | { |
| 1783 | |
| 1784 | #ifdef BDEBUG |
Haibo Huang | 165065a | 2018-07-23 17:26:52 -0700 | [diff] [blame] | 1785 | if (pcap_optimizer_debug > 1 || pcap_print_dot_graph) { |
The Android Open Source Project | 478ab6c | 2009-03-03 19:30:05 -0800 | [diff] [blame] | 1786 | printf("opt_loop(root, %d) begin\n", do_stmts); |
Elliott Hughes | 965a4b5 | 2017-05-15 10:37:39 -0700 | [diff] [blame] | 1787 | opt_dump(cstate, ic); |
The Android Open Source Project | 478ab6c | 2009-03-03 19:30:05 -0800 | [diff] [blame] | 1788 | } |
| 1789 | #endif |
| 1790 | do { |
Elliott Hughes | 965a4b5 | 2017-05-15 10:37:39 -0700 | [diff] [blame] | 1791 | opt_state->done = 1; |
| 1792 | find_levels(opt_state, ic); |
| 1793 | find_dom(opt_state, ic->root); |
| 1794 | find_closure(opt_state, ic->root); |
| 1795 | find_ud(opt_state, ic->root); |
| 1796 | find_edom(opt_state, ic->root); |
| 1797 | opt_blks(cstate, opt_state, ic, do_stmts); |
The Android Open Source Project | 478ab6c | 2009-03-03 19:30:05 -0800 | [diff] [blame] | 1798 | #ifdef BDEBUG |
Haibo Huang | 165065a | 2018-07-23 17:26:52 -0700 | [diff] [blame] | 1799 | if (pcap_optimizer_debug > 1 || pcap_print_dot_graph) { |
Elliott Hughes | 965a4b5 | 2017-05-15 10:37:39 -0700 | [diff] [blame] | 1800 | printf("opt_loop(root, %d) bottom, done=%d\n", do_stmts, opt_state->done); |
| 1801 | opt_dump(cstate, ic); |
The Android Open Source Project | 478ab6c | 2009-03-03 19:30:05 -0800 | [diff] [blame] | 1802 | } |
| 1803 | #endif |
Elliott Hughes | 965a4b5 | 2017-05-15 10:37:39 -0700 | [diff] [blame] | 1804 | } while (!opt_state->done); |
The Android Open Source Project | 478ab6c | 2009-03-03 19:30:05 -0800 | [diff] [blame] | 1805 | } |
| 1806 | |
| 1807 | /* |
| 1808 | * Optimize the filter code in its dag representation. |
| 1809 | */ |
| 1810 | void |
Elliott Hughes | 965a4b5 | 2017-05-15 10:37:39 -0700 | [diff] [blame] | 1811 | bpf_optimize(compiler_state_t *cstate, struct icode *ic) |
The Android Open Source Project | 478ab6c | 2009-03-03 19:30:05 -0800 | [diff] [blame] | 1812 | { |
Elliott Hughes | 965a4b5 | 2017-05-15 10:37:39 -0700 | [diff] [blame] | 1813 | opt_state_t opt_state; |
The Android Open Source Project | 478ab6c | 2009-03-03 19:30:05 -0800 | [diff] [blame] | 1814 | |
Elliott Hughes | 965a4b5 | 2017-05-15 10:37:39 -0700 | [diff] [blame] | 1815 | opt_init(cstate, &opt_state, ic); |
| 1816 | opt_loop(cstate, &opt_state, ic, 0); |
| 1817 | opt_loop(cstate, &opt_state, ic, 1); |
| 1818 | intern_blocks(&opt_state, ic); |
The Android Open Source Project | 478ab6c | 2009-03-03 19:30:05 -0800 | [diff] [blame] | 1819 | #ifdef BDEBUG |
Haibo Huang | 165065a | 2018-07-23 17:26:52 -0700 | [diff] [blame] | 1820 | if (pcap_optimizer_debug > 1 || pcap_print_dot_graph) { |
The Android Open Source Project | 478ab6c | 2009-03-03 19:30:05 -0800 | [diff] [blame] | 1821 | printf("after intern_blocks()\n"); |
Elliott Hughes | 965a4b5 | 2017-05-15 10:37:39 -0700 | [diff] [blame] | 1822 | opt_dump(cstate, ic); |
The Android Open Source Project | 478ab6c | 2009-03-03 19:30:05 -0800 | [diff] [blame] | 1823 | } |
| 1824 | #endif |
Elliott Hughes | 965a4b5 | 2017-05-15 10:37:39 -0700 | [diff] [blame] | 1825 | opt_root(&ic->root); |
The Android Open Source Project | 478ab6c | 2009-03-03 19:30:05 -0800 | [diff] [blame] | 1826 | #ifdef BDEBUG |
Haibo Huang | 165065a | 2018-07-23 17:26:52 -0700 | [diff] [blame] | 1827 | if (pcap_optimizer_debug > 1 || pcap_print_dot_graph) { |
The Android Open Source Project | 478ab6c | 2009-03-03 19:30:05 -0800 | [diff] [blame] | 1828 | printf("after opt_root()\n"); |
Elliott Hughes | 965a4b5 | 2017-05-15 10:37:39 -0700 | [diff] [blame] | 1829 | opt_dump(cstate, ic); |
The Android Open Source Project | 478ab6c | 2009-03-03 19:30:05 -0800 | [diff] [blame] | 1830 | } |
| 1831 | #endif |
Elliott Hughes | 965a4b5 | 2017-05-15 10:37:39 -0700 | [diff] [blame] | 1832 | opt_cleanup(&opt_state); |
The Android Open Source Project | 478ab6c | 2009-03-03 19:30:05 -0800 | [diff] [blame] | 1833 | } |
| 1834 | |
| 1835 | static void |
Elliott Hughes | 965a4b5 | 2017-05-15 10:37:39 -0700 | [diff] [blame] | 1836 | make_marks(struct icode *ic, struct block *p) |
The Android Open Source Project | 478ab6c | 2009-03-03 19:30:05 -0800 | [diff] [blame] | 1837 | { |
Elliott Hughes | 965a4b5 | 2017-05-15 10:37:39 -0700 | [diff] [blame] | 1838 | if (!isMarked(ic, p)) { |
| 1839 | Mark(ic, p); |
The Android Open Source Project | 478ab6c | 2009-03-03 19:30:05 -0800 | [diff] [blame] | 1840 | if (BPF_CLASS(p->s.code) != BPF_RET) { |
Elliott Hughes | 965a4b5 | 2017-05-15 10:37:39 -0700 | [diff] [blame] | 1841 | make_marks(ic, JT(p)); |
| 1842 | make_marks(ic, JF(p)); |
The Android Open Source Project | 478ab6c | 2009-03-03 19:30:05 -0800 | [diff] [blame] | 1843 | } |
| 1844 | } |
| 1845 | } |
| 1846 | |
| 1847 | /* |
Elliott Hughes | 965a4b5 | 2017-05-15 10:37:39 -0700 | [diff] [blame] | 1848 | * Mark code array such that isMarked(ic->cur_mark, i) is true |
The Android Open Source Project | 478ab6c | 2009-03-03 19:30:05 -0800 | [diff] [blame] | 1849 | * only for nodes that are alive. |
| 1850 | */ |
| 1851 | static void |
Elliott Hughes | 965a4b5 | 2017-05-15 10:37:39 -0700 | [diff] [blame] | 1852 | mark_code(struct icode *ic) |
The Android Open Source Project | 478ab6c | 2009-03-03 19:30:05 -0800 | [diff] [blame] | 1853 | { |
Elliott Hughes | 965a4b5 | 2017-05-15 10:37:39 -0700 | [diff] [blame] | 1854 | ic->cur_mark += 1; |
| 1855 | make_marks(ic, ic->root); |
The Android Open Source Project | 478ab6c | 2009-03-03 19:30:05 -0800 | [diff] [blame] | 1856 | } |
| 1857 | |
| 1858 | /* |
| 1859 | * True iff the two stmt lists load the same value from the packet into |
| 1860 | * the accumulator. |
| 1861 | */ |
| 1862 | static int |
JP Abgrall | 511eca3 | 2014-02-12 13:46:45 -0800 | [diff] [blame] | 1863 | eq_slist(struct slist *x, struct slist *y) |
The Android Open Source Project | 478ab6c | 2009-03-03 19:30:05 -0800 | [diff] [blame] | 1864 | { |
Haibo Huang | 165065a | 2018-07-23 17:26:52 -0700 | [diff] [blame] | 1865 | for (;;) { |
The Android Open Source Project | 478ab6c | 2009-03-03 19:30:05 -0800 | [diff] [blame] | 1866 | while (x && x->s.code == NOP) |
| 1867 | x = x->next; |
| 1868 | while (y && y->s.code == NOP) |
| 1869 | y = y->next; |
| 1870 | if (x == 0) |
| 1871 | return y == 0; |
| 1872 | if (y == 0) |
| 1873 | return x == 0; |
| 1874 | if (x->s.code != y->s.code || x->s.k != y->s.k) |
| 1875 | return 0; |
| 1876 | x = x->next; |
| 1877 | y = y->next; |
| 1878 | } |
| 1879 | } |
| 1880 | |
| 1881 | static inline int |
JP Abgrall | 511eca3 | 2014-02-12 13:46:45 -0800 | [diff] [blame] | 1882 | eq_blk(struct block *b0, struct block *b1) |
The Android Open Source Project | 478ab6c | 2009-03-03 19:30:05 -0800 | [diff] [blame] | 1883 | { |
| 1884 | if (b0->s.code == b1->s.code && |
| 1885 | b0->s.k == b1->s.k && |
| 1886 | b0->et.succ == b1->et.succ && |
| 1887 | b0->ef.succ == b1->ef.succ) |
| 1888 | return eq_slist(b0->stmts, b1->stmts); |
| 1889 | return 0; |
| 1890 | } |
| 1891 | |
| 1892 | static void |
Elliott Hughes | 965a4b5 | 2017-05-15 10:37:39 -0700 | [diff] [blame] | 1893 | intern_blocks(opt_state_t *opt_state, struct icode *ic) |
The Android Open Source Project | 478ab6c | 2009-03-03 19:30:05 -0800 | [diff] [blame] | 1894 | { |
| 1895 | struct block *p; |
| 1896 | int i, j; |
| 1897 | int done1; /* don't shadow global */ |
| 1898 | top: |
| 1899 | done1 = 1; |
Elliott Hughes | 965a4b5 | 2017-05-15 10:37:39 -0700 | [diff] [blame] | 1900 | for (i = 0; i < opt_state->n_blocks; ++i) |
| 1901 | opt_state->blocks[i]->link = 0; |
The Android Open Source Project | 478ab6c | 2009-03-03 19:30:05 -0800 | [diff] [blame] | 1902 | |
Elliott Hughes | 965a4b5 | 2017-05-15 10:37:39 -0700 | [diff] [blame] | 1903 | mark_code(ic); |
The Android Open Source Project | 478ab6c | 2009-03-03 19:30:05 -0800 | [diff] [blame] | 1904 | |
Elliott Hughes | 965a4b5 | 2017-05-15 10:37:39 -0700 | [diff] [blame] | 1905 | for (i = opt_state->n_blocks - 1; --i >= 0; ) { |
| 1906 | if (!isMarked(ic, opt_state->blocks[i])) |
The Android Open Source Project | 478ab6c | 2009-03-03 19:30:05 -0800 | [diff] [blame] | 1907 | continue; |
Elliott Hughes | 965a4b5 | 2017-05-15 10:37:39 -0700 | [diff] [blame] | 1908 | for (j = i + 1; j < opt_state->n_blocks; ++j) { |
| 1909 | if (!isMarked(ic, opt_state->blocks[j])) |
The Android Open Source Project | 478ab6c | 2009-03-03 19:30:05 -0800 | [diff] [blame] | 1910 | continue; |
Elliott Hughes | 965a4b5 | 2017-05-15 10:37:39 -0700 | [diff] [blame] | 1911 | if (eq_blk(opt_state->blocks[i], opt_state->blocks[j])) { |
| 1912 | opt_state->blocks[i]->link = opt_state->blocks[j]->link ? |
| 1913 | opt_state->blocks[j]->link : opt_state->blocks[j]; |
The Android Open Source Project | 478ab6c | 2009-03-03 19:30:05 -0800 | [diff] [blame] | 1914 | break; |
| 1915 | } |
| 1916 | } |
| 1917 | } |
Elliott Hughes | 965a4b5 | 2017-05-15 10:37:39 -0700 | [diff] [blame] | 1918 | for (i = 0; i < opt_state->n_blocks; ++i) { |
| 1919 | p = opt_state->blocks[i]; |
The Android Open Source Project | 478ab6c | 2009-03-03 19:30:05 -0800 | [diff] [blame] | 1920 | if (JT(p) == 0) |
| 1921 | continue; |
| 1922 | if (JT(p)->link) { |
| 1923 | done1 = 0; |
| 1924 | JT(p) = JT(p)->link; |
| 1925 | } |
| 1926 | if (JF(p)->link) { |
| 1927 | done1 = 0; |
| 1928 | JF(p) = JF(p)->link; |
| 1929 | } |
| 1930 | } |
| 1931 | if (!done1) |
| 1932 | goto top; |
| 1933 | } |
| 1934 | |
| 1935 | static void |
Elliott Hughes | 965a4b5 | 2017-05-15 10:37:39 -0700 | [diff] [blame] | 1936 | opt_cleanup(opt_state_t *opt_state) |
The Android Open Source Project | 478ab6c | 2009-03-03 19:30:05 -0800 | [diff] [blame] | 1937 | { |
Elliott Hughes | 965a4b5 | 2017-05-15 10:37:39 -0700 | [diff] [blame] | 1938 | free((void *)opt_state->vnode_base); |
| 1939 | free((void *)opt_state->vmap); |
| 1940 | free((void *)opt_state->edges); |
| 1941 | free((void *)opt_state->space); |
| 1942 | free((void *)opt_state->levels); |
| 1943 | free((void *)opt_state->blocks); |
The Android Open Source Project | 478ab6c | 2009-03-03 19:30:05 -0800 | [diff] [blame] | 1944 | } |
| 1945 | |
| 1946 | /* |
| 1947 | * Return the number of stmts in 's'. |
| 1948 | */ |
JP Abgrall | 511eca3 | 2014-02-12 13:46:45 -0800 | [diff] [blame] | 1949 | static u_int |
| 1950 | slength(struct slist *s) |
The Android Open Source Project | 478ab6c | 2009-03-03 19:30:05 -0800 | [diff] [blame] | 1951 | { |
JP Abgrall | 511eca3 | 2014-02-12 13:46:45 -0800 | [diff] [blame] | 1952 | u_int n = 0; |
The Android Open Source Project | 478ab6c | 2009-03-03 19:30:05 -0800 | [diff] [blame] | 1953 | |
| 1954 | for (; s; s = s->next) |
| 1955 | if (s->s.code != NOP) |
| 1956 | ++n; |
| 1957 | return n; |
| 1958 | } |
| 1959 | |
| 1960 | /* |
| 1961 | * Return the number of nodes reachable by 'p'. |
| 1962 | * All nodes should be initially unmarked. |
| 1963 | */ |
| 1964 | static int |
Elliott Hughes | 965a4b5 | 2017-05-15 10:37:39 -0700 | [diff] [blame] | 1965 | count_blocks(struct icode *ic, struct block *p) |
The Android Open Source Project | 478ab6c | 2009-03-03 19:30:05 -0800 | [diff] [blame] | 1966 | { |
Elliott Hughes | 965a4b5 | 2017-05-15 10:37:39 -0700 | [diff] [blame] | 1967 | if (p == 0 || isMarked(ic, p)) |
The Android Open Source Project | 478ab6c | 2009-03-03 19:30:05 -0800 | [diff] [blame] | 1968 | return 0; |
Elliott Hughes | 965a4b5 | 2017-05-15 10:37:39 -0700 | [diff] [blame] | 1969 | Mark(ic, p); |
| 1970 | return count_blocks(ic, JT(p)) + count_blocks(ic, JF(p)) + 1; |
The Android Open Source Project | 478ab6c | 2009-03-03 19:30:05 -0800 | [diff] [blame] | 1971 | } |
| 1972 | |
| 1973 | /* |
| 1974 | * Do a depth first search on the flow graph, numbering the |
| 1975 | * the basic blocks, and entering them into the 'blocks' array.` |
| 1976 | */ |
| 1977 | static void |
Elliott Hughes | 965a4b5 | 2017-05-15 10:37:39 -0700 | [diff] [blame] | 1978 | number_blks_r(opt_state_t *opt_state, struct icode *ic, struct block *p) |
The Android Open Source Project | 478ab6c | 2009-03-03 19:30:05 -0800 | [diff] [blame] | 1979 | { |
| 1980 | int n; |
| 1981 | |
Elliott Hughes | 965a4b5 | 2017-05-15 10:37:39 -0700 | [diff] [blame] | 1982 | if (p == 0 || isMarked(ic, p)) |
The Android Open Source Project | 478ab6c | 2009-03-03 19:30:05 -0800 | [diff] [blame] | 1983 | return; |
| 1984 | |
Elliott Hughes | 965a4b5 | 2017-05-15 10:37:39 -0700 | [diff] [blame] | 1985 | Mark(ic, p); |
| 1986 | n = opt_state->n_blocks++; |
The Android Open Source Project | 478ab6c | 2009-03-03 19:30:05 -0800 | [diff] [blame] | 1987 | p->id = n; |
Elliott Hughes | 965a4b5 | 2017-05-15 10:37:39 -0700 | [diff] [blame] | 1988 | opt_state->blocks[n] = p; |
The Android Open Source Project | 478ab6c | 2009-03-03 19:30:05 -0800 | [diff] [blame] | 1989 | |
Elliott Hughes | 965a4b5 | 2017-05-15 10:37:39 -0700 | [diff] [blame] | 1990 | number_blks_r(opt_state, ic, JT(p)); |
| 1991 | number_blks_r(opt_state, ic, JF(p)); |
The Android Open Source Project | 478ab6c | 2009-03-03 19:30:05 -0800 | [diff] [blame] | 1992 | } |
| 1993 | |
| 1994 | /* |
| 1995 | * Return the number of stmts in the flowgraph reachable by 'p'. |
| 1996 | * The nodes should be unmarked before calling. |
| 1997 | * |
| 1998 | * Note that "stmts" means "instructions", and that this includes |
| 1999 | * |
| 2000 | * side-effect statements in 'p' (slength(p->stmts)); |
| 2001 | * |
| 2002 | * statements in the true branch from 'p' (count_stmts(JT(p))); |
| 2003 | * |
| 2004 | * statements in the false branch from 'p' (count_stmts(JF(p))); |
| 2005 | * |
| 2006 | * the conditional jump itself (1); |
| 2007 | * |
| 2008 | * an extra long jump if the true branch requires it (p->longjt); |
| 2009 | * |
| 2010 | * an extra long jump if the false branch requires it (p->longjf). |
| 2011 | */ |
JP Abgrall | 511eca3 | 2014-02-12 13:46:45 -0800 | [diff] [blame] | 2012 | static u_int |
Elliott Hughes | 965a4b5 | 2017-05-15 10:37:39 -0700 | [diff] [blame] | 2013 | count_stmts(struct icode *ic, struct block *p) |
The Android Open Source Project | 478ab6c | 2009-03-03 19:30:05 -0800 | [diff] [blame] | 2014 | { |
JP Abgrall | 511eca3 | 2014-02-12 13:46:45 -0800 | [diff] [blame] | 2015 | u_int n; |
The Android Open Source Project | 478ab6c | 2009-03-03 19:30:05 -0800 | [diff] [blame] | 2016 | |
Elliott Hughes | 965a4b5 | 2017-05-15 10:37:39 -0700 | [diff] [blame] | 2017 | if (p == 0 || isMarked(ic, p)) |
The Android Open Source Project | 478ab6c | 2009-03-03 19:30:05 -0800 | [diff] [blame] | 2018 | return 0; |
Elliott Hughes | 965a4b5 | 2017-05-15 10:37:39 -0700 | [diff] [blame] | 2019 | Mark(ic, p); |
| 2020 | n = count_stmts(ic, JT(p)) + count_stmts(ic, JF(p)); |
The Android Open Source Project | 478ab6c | 2009-03-03 19:30:05 -0800 | [diff] [blame] | 2021 | return slength(p->stmts) + n + 1 + p->longjt + p->longjf; |
| 2022 | } |
| 2023 | |
| 2024 | /* |
| 2025 | * Allocate memory. All allocation is done before optimization |
| 2026 | * is begun. A linear bound on the size of all data structures is computed |
| 2027 | * from the total number of blocks and/or statements. |
| 2028 | */ |
| 2029 | static void |
Elliott Hughes | 965a4b5 | 2017-05-15 10:37:39 -0700 | [diff] [blame] | 2030 | opt_init(compiler_state_t *cstate, opt_state_t *opt_state, struct icode *ic) |
The Android Open Source Project | 478ab6c | 2009-03-03 19:30:05 -0800 | [diff] [blame] | 2031 | { |
| 2032 | bpf_u_int32 *p; |
| 2033 | int i, n, max_stmts; |
| 2034 | |
| 2035 | /* |
| 2036 | * First, count the blocks, so we can malloc an array to map |
| 2037 | * block number to block. Then, put the blocks into the array. |
| 2038 | */ |
Elliott Hughes | 965a4b5 | 2017-05-15 10:37:39 -0700 | [diff] [blame] | 2039 | unMarkAll(ic); |
| 2040 | n = count_blocks(ic, ic->root); |
| 2041 | opt_state->blocks = (struct block **)calloc(n, sizeof(*opt_state->blocks)); |
| 2042 | if (opt_state->blocks == NULL) |
| 2043 | bpf_error(cstate, "malloc"); |
| 2044 | unMarkAll(ic); |
| 2045 | opt_state->n_blocks = 0; |
| 2046 | number_blks_r(opt_state, ic, ic->root); |
The Android Open Source Project | 478ab6c | 2009-03-03 19:30:05 -0800 | [diff] [blame] | 2047 | |
Elliott Hughes | 965a4b5 | 2017-05-15 10:37:39 -0700 | [diff] [blame] | 2048 | opt_state->n_edges = 2 * opt_state->n_blocks; |
| 2049 | opt_state->edges = (struct edge **)calloc(opt_state->n_edges, sizeof(*opt_state->edges)); |
| 2050 | if (opt_state->edges == NULL) |
| 2051 | bpf_error(cstate, "malloc"); |
The Android Open Source Project | 478ab6c | 2009-03-03 19:30:05 -0800 | [diff] [blame] | 2052 | |
| 2053 | /* |
| 2054 | * The number of levels is bounded by the number of nodes. |
| 2055 | */ |
Elliott Hughes | 965a4b5 | 2017-05-15 10:37:39 -0700 | [diff] [blame] | 2056 | opt_state->levels = (struct block **)calloc(opt_state->n_blocks, sizeof(*opt_state->levels)); |
| 2057 | if (opt_state->levels == NULL) |
| 2058 | bpf_error(cstate, "malloc"); |
The Android Open Source Project | 478ab6c | 2009-03-03 19:30:05 -0800 | [diff] [blame] | 2059 | |
Elliott Hughes | 965a4b5 | 2017-05-15 10:37:39 -0700 | [diff] [blame] | 2060 | opt_state->edgewords = opt_state->n_edges / (8 * sizeof(bpf_u_int32)) + 1; |
| 2061 | opt_state->nodewords = opt_state->n_blocks / (8 * sizeof(bpf_u_int32)) + 1; |
The Android Open Source Project | 478ab6c | 2009-03-03 19:30:05 -0800 | [diff] [blame] | 2062 | |
| 2063 | /* XXX */ |
Elliott Hughes | 965a4b5 | 2017-05-15 10:37:39 -0700 | [diff] [blame] | 2064 | opt_state->space = (bpf_u_int32 *)malloc(2 * opt_state->n_blocks * opt_state->nodewords * sizeof(*opt_state->space) |
| 2065 | + opt_state->n_edges * opt_state->edgewords * sizeof(*opt_state->space)); |
| 2066 | if (opt_state->space == NULL) |
| 2067 | bpf_error(cstate, "malloc"); |
| 2068 | p = opt_state->space; |
| 2069 | opt_state->all_dom_sets = p; |
The Android Open Source Project | 478ab6c | 2009-03-03 19:30:05 -0800 | [diff] [blame] | 2070 | for (i = 0; i < n; ++i) { |
Elliott Hughes | 965a4b5 | 2017-05-15 10:37:39 -0700 | [diff] [blame] | 2071 | opt_state->blocks[i]->dom = p; |
| 2072 | p += opt_state->nodewords; |
The Android Open Source Project | 478ab6c | 2009-03-03 19:30:05 -0800 | [diff] [blame] | 2073 | } |
Elliott Hughes | 965a4b5 | 2017-05-15 10:37:39 -0700 | [diff] [blame] | 2074 | opt_state->all_closure_sets = p; |
The Android Open Source Project | 478ab6c | 2009-03-03 19:30:05 -0800 | [diff] [blame] | 2075 | for (i = 0; i < n; ++i) { |
Elliott Hughes | 965a4b5 | 2017-05-15 10:37:39 -0700 | [diff] [blame] | 2076 | opt_state->blocks[i]->closure = p; |
| 2077 | p += opt_state->nodewords; |
The Android Open Source Project | 478ab6c | 2009-03-03 19:30:05 -0800 | [diff] [blame] | 2078 | } |
Elliott Hughes | 965a4b5 | 2017-05-15 10:37:39 -0700 | [diff] [blame] | 2079 | opt_state->all_edge_sets = p; |
The Android Open Source Project | 478ab6c | 2009-03-03 19:30:05 -0800 | [diff] [blame] | 2080 | for (i = 0; i < n; ++i) { |
Elliott Hughes | 965a4b5 | 2017-05-15 10:37:39 -0700 | [diff] [blame] | 2081 | register struct block *b = opt_state->blocks[i]; |
The Android Open Source Project | 478ab6c | 2009-03-03 19:30:05 -0800 | [diff] [blame] | 2082 | |
| 2083 | b->et.edom = p; |
Elliott Hughes | 965a4b5 | 2017-05-15 10:37:39 -0700 | [diff] [blame] | 2084 | p += opt_state->edgewords; |
The Android Open Source Project | 478ab6c | 2009-03-03 19:30:05 -0800 | [diff] [blame] | 2085 | b->ef.edom = p; |
Elliott Hughes | 965a4b5 | 2017-05-15 10:37:39 -0700 | [diff] [blame] | 2086 | p += opt_state->edgewords; |
The Android Open Source Project | 478ab6c | 2009-03-03 19:30:05 -0800 | [diff] [blame] | 2087 | b->et.id = i; |
Elliott Hughes | 965a4b5 | 2017-05-15 10:37:39 -0700 | [diff] [blame] | 2088 | opt_state->edges[i] = &b->et; |
| 2089 | b->ef.id = opt_state->n_blocks + i; |
| 2090 | opt_state->edges[opt_state->n_blocks + i] = &b->ef; |
The Android Open Source Project | 478ab6c | 2009-03-03 19:30:05 -0800 | [diff] [blame] | 2091 | b->et.pred = b; |
| 2092 | b->ef.pred = b; |
| 2093 | } |
| 2094 | max_stmts = 0; |
| 2095 | for (i = 0; i < n; ++i) |
Elliott Hughes | 965a4b5 | 2017-05-15 10:37:39 -0700 | [diff] [blame] | 2096 | max_stmts += slength(opt_state->blocks[i]->stmts) + 1; |
The Android Open Source Project | 478ab6c | 2009-03-03 19:30:05 -0800 | [diff] [blame] | 2097 | /* |
| 2098 | * We allocate at most 3 value numbers per statement, |
| 2099 | * so this is an upper bound on the number of valnodes |
| 2100 | * we'll need. |
| 2101 | */ |
Elliott Hughes | 965a4b5 | 2017-05-15 10:37:39 -0700 | [diff] [blame] | 2102 | opt_state->maxval = 3 * max_stmts; |
| 2103 | opt_state->vmap = (struct vmapinfo *)calloc(opt_state->maxval, sizeof(*opt_state->vmap)); |
| 2104 | opt_state->vnode_base = (struct valnode *)calloc(opt_state->maxval, sizeof(*opt_state->vnode_base)); |
| 2105 | if (opt_state->vmap == NULL || opt_state->vnode_base == NULL) |
| 2106 | bpf_error(cstate, "malloc"); |
The Android Open Source Project | 478ab6c | 2009-03-03 19:30:05 -0800 | [diff] [blame] | 2107 | } |
| 2108 | |
| 2109 | /* |
Elliott Hughes | 965a4b5 | 2017-05-15 10:37:39 -0700 | [diff] [blame] | 2110 | * This is only used when supporting optimizer debugging. It is |
| 2111 | * global state, so do *not* do more than one compile in parallel |
| 2112 | * and expect it to provide meaningful information. |
The Android Open Source Project | 478ab6c | 2009-03-03 19:30:05 -0800 | [diff] [blame] | 2113 | */ |
The Android Open Source Project | 478ab6c | 2009-03-03 19:30:05 -0800 | [diff] [blame] | 2114 | #ifdef BDEBUG |
Haibo Huang | 165065a | 2018-07-23 17:26:52 -0700 | [diff] [blame] | 2115 | int bids[NBIDS]; |
The Android Open Source Project | 478ab6c | 2009-03-03 19:30:05 -0800 | [diff] [blame] | 2116 | #endif |
| 2117 | |
| 2118 | /* |
| 2119 | * Returns true if successful. Returns false if a branch has |
| 2120 | * an offset that is too large. If so, we have marked that |
| 2121 | * branch so that on a subsequent iteration, it will be treated |
| 2122 | * properly. |
| 2123 | */ |
| 2124 | static int |
Elliott Hughes | 965a4b5 | 2017-05-15 10:37:39 -0700 | [diff] [blame] | 2125 | convert_code_r(compiler_state_t *cstate, conv_state_t *conv_state, |
| 2126 | struct icode *ic, struct block *p) |
The Android Open Source Project | 478ab6c | 2009-03-03 19:30:05 -0800 | [diff] [blame] | 2127 | { |
| 2128 | struct bpf_insn *dst; |
| 2129 | struct slist *src; |
Elliott Hughes | 965a4b5 | 2017-05-15 10:37:39 -0700 | [diff] [blame] | 2130 | u_int slen; |
The Android Open Source Project | 478ab6c | 2009-03-03 19:30:05 -0800 | [diff] [blame] | 2131 | u_int off; |
Haibo Huang | 165065a | 2018-07-23 17:26:52 -0700 | [diff] [blame] | 2132 | u_int extrajmps; /* number of extra jumps inserted */ |
The Android Open Source Project | 478ab6c | 2009-03-03 19:30:05 -0800 | [diff] [blame] | 2133 | struct slist **offset = NULL; |
| 2134 | |
Elliott Hughes | 965a4b5 | 2017-05-15 10:37:39 -0700 | [diff] [blame] | 2135 | if (p == 0 || isMarked(ic, p)) |
The Android Open Source Project | 478ab6c | 2009-03-03 19:30:05 -0800 | [diff] [blame] | 2136 | return (1); |
Elliott Hughes | 965a4b5 | 2017-05-15 10:37:39 -0700 | [diff] [blame] | 2137 | Mark(ic, p); |
The Android Open Source Project | 478ab6c | 2009-03-03 19:30:05 -0800 | [diff] [blame] | 2138 | |
Elliott Hughes | 965a4b5 | 2017-05-15 10:37:39 -0700 | [diff] [blame] | 2139 | if (convert_code_r(cstate, conv_state, ic, JF(p)) == 0) |
The Android Open Source Project | 478ab6c | 2009-03-03 19:30:05 -0800 | [diff] [blame] | 2140 | return (0); |
Elliott Hughes | 965a4b5 | 2017-05-15 10:37:39 -0700 | [diff] [blame] | 2141 | if (convert_code_r(cstate, conv_state, ic, JT(p)) == 0) |
The Android Open Source Project | 478ab6c | 2009-03-03 19:30:05 -0800 | [diff] [blame] | 2142 | return (0); |
| 2143 | |
| 2144 | slen = slength(p->stmts); |
Elliott Hughes | 965a4b5 | 2017-05-15 10:37:39 -0700 | [diff] [blame] | 2145 | dst = conv_state->ftail -= (slen + 1 + p->longjt + p->longjf); |
The Android Open Source Project | 478ab6c | 2009-03-03 19:30:05 -0800 | [diff] [blame] | 2146 | /* inflate length by any extra jumps */ |
| 2147 | |
Elliott Hughes | 965a4b5 | 2017-05-15 10:37:39 -0700 | [diff] [blame] | 2148 | p->offset = (int)(dst - conv_state->fstart); |
The Android Open Source Project | 478ab6c | 2009-03-03 19:30:05 -0800 | [diff] [blame] | 2149 | |
| 2150 | /* generate offset[] for convenience */ |
| 2151 | if (slen) { |
| 2152 | offset = (struct slist **)calloc(slen, sizeof(struct slist *)); |
| 2153 | if (!offset) { |
Elliott Hughes | 965a4b5 | 2017-05-15 10:37:39 -0700 | [diff] [blame] | 2154 | bpf_error(cstate, "not enough core"); |
The Android Open Source Project | 478ab6c | 2009-03-03 19:30:05 -0800 | [diff] [blame] | 2155 | /*NOTREACHED*/ |
| 2156 | } |
| 2157 | } |
| 2158 | src = p->stmts; |
| 2159 | for (off = 0; off < slen && src; off++) { |
| 2160 | #if 0 |
| 2161 | printf("off=%d src=%x\n", off, src); |
| 2162 | #endif |
| 2163 | offset[off] = src; |
| 2164 | src = src->next; |
| 2165 | } |
| 2166 | |
| 2167 | off = 0; |
| 2168 | for (src = p->stmts; src; src = src->next) { |
| 2169 | if (src->s.code == NOP) |
| 2170 | continue; |
| 2171 | dst->code = (u_short)src->s.code; |
| 2172 | dst->k = src->s.k; |
| 2173 | |
| 2174 | /* fill block-local relative jump */ |
| 2175 | if (BPF_CLASS(src->s.code) != BPF_JMP || src->s.code == (BPF_JMP|BPF_JA)) { |
| 2176 | #if 0 |
| 2177 | if (src->s.jt || src->s.jf) { |
Elliott Hughes | 965a4b5 | 2017-05-15 10:37:39 -0700 | [diff] [blame] | 2178 | bpf_error(cstate, "illegal jmp destination"); |
The Android Open Source Project | 478ab6c | 2009-03-03 19:30:05 -0800 | [diff] [blame] | 2179 | /*NOTREACHED*/ |
| 2180 | } |
| 2181 | #endif |
| 2182 | goto filled; |
| 2183 | } |
| 2184 | if (off == slen - 2) /*???*/ |
| 2185 | goto filled; |
| 2186 | |
| 2187 | { |
Elliott Hughes | 965a4b5 | 2017-05-15 10:37:39 -0700 | [diff] [blame] | 2188 | u_int i; |
The Android Open Source Project | 478ab6c | 2009-03-03 19:30:05 -0800 | [diff] [blame] | 2189 | int jt, jf; |
Haibo Huang | 165065a | 2018-07-23 17:26:52 -0700 | [diff] [blame] | 2190 | const char ljerr[] = "%s for block-local relative jump: off=%d"; |
The Android Open Source Project | 478ab6c | 2009-03-03 19:30:05 -0800 | [diff] [blame] | 2191 | |
| 2192 | #if 0 |
| 2193 | printf("code=%x off=%d %x %x\n", src->s.code, |
| 2194 | off, src->s.jt, src->s.jf); |
| 2195 | #endif |
| 2196 | |
| 2197 | if (!src->s.jt || !src->s.jf) { |
Elliott Hughes | 965a4b5 | 2017-05-15 10:37:39 -0700 | [diff] [blame] | 2198 | bpf_error(cstate, ljerr, "no jmp destination", off); |
The Android Open Source Project | 478ab6c | 2009-03-03 19:30:05 -0800 | [diff] [blame] | 2199 | /*NOTREACHED*/ |
| 2200 | } |
| 2201 | |
| 2202 | jt = jf = 0; |
| 2203 | for (i = 0; i < slen; i++) { |
| 2204 | if (offset[i] == src->s.jt) { |
| 2205 | if (jt) { |
Elliott Hughes | 965a4b5 | 2017-05-15 10:37:39 -0700 | [diff] [blame] | 2206 | bpf_error(cstate, ljerr, "multiple matches", off); |
The Android Open Source Project | 478ab6c | 2009-03-03 19:30:05 -0800 | [diff] [blame] | 2207 | /*NOTREACHED*/ |
| 2208 | } |
| 2209 | |
Haibo Huang | 165065a | 2018-07-23 17:26:52 -0700 | [diff] [blame] | 2210 | if (i - off - 1 >= 256) { |
| 2211 | bpf_error(cstate, ljerr, "out-of-range jump", off); |
| 2212 | /*NOTREACHED*/ |
| 2213 | } |
| 2214 | dst->jt = (u_char)(i - off - 1); |
The Android Open Source Project | 478ab6c | 2009-03-03 19:30:05 -0800 | [diff] [blame] | 2215 | jt++; |
| 2216 | } |
| 2217 | if (offset[i] == src->s.jf) { |
| 2218 | if (jf) { |
Elliott Hughes | 965a4b5 | 2017-05-15 10:37:39 -0700 | [diff] [blame] | 2219 | bpf_error(cstate, ljerr, "multiple matches", off); |
The Android Open Source Project | 478ab6c | 2009-03-03 19:30:05 -0800 | [diff] [blame] | 2220 | /*NOTREACHED*/ |
| 2221 | } |
Haibo Huang | 165065a | 2018-07-23 17:26:52 -0700 | [diff] [blame] | 2222 | if (i - off - 1 >= 256) { |
| 2223 | bpf_error(cstate, ljerr, "out-of-range jump", off); |
| 2224 | /*NOTREACHED*/ |
| 2225 | } |
| 2226 | dst->jf = (u_char)(i - off - 1); |
The Android Open Source Project | 478ab6c | 2009-03-03 19:30:05 -0800 | [diff] [blame] | 2227 | jf++; |
| 2228 | } |
| 2229 | } |
| 2230 | if (!jt || !jf) { |
Elliott Hughes | 965a4b5 | 2017-05-15 10:37:39 -0700 | [diff] [blame] | 2231 | bpf_error(cstate, ljerr, "no destination found", off); |
The Android Open Source Project | 478ab6c | 2009-03-03 19:30:05 -0800 | [diff] [blame] | 2232 | /*NOTREACHED*/ |
| 2233 | } |
| 2234 | } |
| 2235 | filled: |
| 2236 | ++dst; |
| 2237 | ++off; |
| 2238 | } |
| 2239 | if (offset) |
| 2240 | free(offset); |
| 2241 | |
| 2242 | #ifdef BDEBUG |
Haibo Huang | 165065a | 2018-07-23 17:26:52 -0700 | [diff] [blame] | 2243 | if (dst - conv_state->fstart < NBIDS) |
| 2244 | bids[dst - conv_state->fstart] = p->id + 1; |
The Android Open Source Project | 478ab6c | 2009-03-03 19:30:05 -0800 | [diff] [blame] | 2245 | #endif |
| 2246 | dst->code = (u_short)p->s.code; |
| 2247 | dst->k = p->s.k; |
| 2248 | if (JT(p)) { |
| 2249 | extrajmps = 0; |
| 2250 | off = JT(p)->offset - (p->offset + slen) - 1; |
| 2251 | if (off >= 256) { |
| 2252 | /* offset too large for branch, must add a jump */ |
| 2253 | if (p->longjt == 0) { |
| 2254 | /* mark this instruction and retry */ |
| 2255 | p->longjt++; |
| 2256 | return(0); |
| 2257 | } |
| 2258 | /* branch if T to following jump */ |
Haibo Huang | 165065a | 2018-07-23 17:26:52 -0700 | [diff] [blame] | 2259 | if (extrajmps >= 256) { |
| 2260 | bpf_error(cstate, "too many extra jumps"); |
| 2261 | /*NOTREACHED*/ |
| 2262 | } |
| 2263 | dst->jt = (u_char)extrajmps; |
The Android Open Source Project | 478ab6c | 2009-03-03 19:30:05 -0800 | [diff] [blame] | 2264 | extrajmps++; |
| 2265 | dst[extrajmps].code = BPF_JMP|BPF_JA; |
| 2266 | dst[extrajmps].k = off - extrajmps; |
| 2267 | } |
| 2268 | else |
Haibo Huang | 165065a | 2018-07-23 17:26:52 -0700 | [diff] [blame] | 2269 | dst->jt = (u_char)off; |
The Android Open Source Project | 478ab6c | 2009-03-03 19:30:05 -0800 | [diff] [blame] | 2270 | off = JF(p)->offset - (p->offset + slen) - 1; |
| 2271 | if (off >= 256) { |
| 2272 | /* offset too large for branch, must add a jump */ |
| 2273 | if (p->longjf == 0) { |
| 2274 | /* mark this instruction and retry */ |
| 2275 | p->longjf++; |
| 2276 | return(0); |
| 2277 | } |
| 2278 | /* branch if F to following jump */ |
| 2279 | /* if two jumps are inserted, F goes to second one */ |
Haibo Huang | 165065a | 2018-07-23 17:26:52 -0700 | [diff] [blame] | 2280 | if (extrajmps >= 256) { |
| 2281 | bpf_error(cstate, "too many extra jumps"); |
| 2282 | /*NOTREACHED*/ |
| 2283 | } |
| 2284 | dst->jf = (u_char)extrajmps; |
The Android Open Source Project | 478ab6c | 2009-03-03 19:30:05 -0800 | [diff] [blame] | 2285 | extrajmps++; |
| 2286 | dst[extrajmps].code = BPF_JMP|BPF_JA; |
| 2287 | dst[extrajmps].k = off - extrajmps; |
| 2288 | } |
| 2289 | else |
Haibo Huang | 165065a | 2018-07-23 17:26:52 -0700 | [diff] [blame] | 2290 | dst->jf = (u_char)off; |
The Android Open Source Project | 478ab6c | 2009-03-03 19:30:05 -0800 | [diff] [blame] | 2291 | } |
| 2292 | return (1); |
| 2293 | } |
| 2294 | |
| 2295 | |
| 2296 | /* |
| 2297 | * Convert flowgraph intermediate representation to the |
| 2298 | * BPF array representation. Set *lenp to the number of instructions. |
| 2299 | * |
| 2300 | * This routine does *NOT* leak the memory pointed to by fp. It *must |
| 2301 | * not* do free(fp) before returning fp; doing so would make no sense, |
| 2302 | * as the BPF array pointed to by the return value of icode_to_fcode() |
| 2303 | * must be valid - it's being returned for use in a bpf_program structure. |
| 2304 | * |
| 2305 | * If it appears that icode_to_fcode() is leaking, the problem is that |
| 2306 | * the program using pcap_compile() is failing to free the memory in |
| 2307 | * the BPF program when it's done - the leak is in the program, not in |
| 2308 | * the routine that happens to be allocating the memory. (By analogy, if |
| 2309 | * a program calls fopen() without ever calling fclose() on the FILE *, |
| 2310 | * it will leak the FILE structure; the leak is not in fopen(), it's in |
| 2311 | * the program.) Change the program to use pcap_freecode() when it's |
| 2312 | * done with the filter program. See the pcap man page. |
| 2313 | */ |
| 2314 | struct bpf_insn * |
Elliott Hughes | 965a4b5 | 2017-05-15 10:37:39 -0700 | [diff] [blame] | 2315 | icode_to_fcode(compiler_state_t *cstate, struct icode *ic, |
| 2316 | struct block *root, u_int *lenp) |
The Android Open Source Project | 478ab6c | 2009-03-03 19:30:05 -0800 | [diff] [blame] | 2317 | { |
JP Abgrall | 511eca3 | 2014-02-12 13:46:45 -0800 | [diff] [blame] | 2318 | u_int n; |
The Android Open Source Project | 478ab6c | 2009-03-03 19:30:05 -0800 | [diff] [blame] | 2319 | struct bpf_insn *fp; |
Elliott Hughes | 965a4b5 | 2017-05-15 10:37:39 -0700 | [diff] [blame] | 2320 | conv_state_t conv_state; |
The Android Open Source Project | 478ab6c | 2009-03-03 19:30:05 -0800 | [diff] [blame] | 2321 | |
| 2322 | /* |
| 2323 | * Loop doing convert_code_r() until no branches remain |
| 2324 | * with too-large offsets. |
| 2325 | */ |
Haibo Huang | 165065a | 2018-07-23 17:26:52 -0700 | [diff] [blame] | 2326 | for (;;) { |
Elliott Hughes | 965a4b5 | 2017-05-15 10:37:39 -0700 | [diff] [blame] | 2327 | unMarkAll(ic); |
| 2328 | n = *lenp = count_stmts(ic, root); |
The Android Open Source Project | 478ab6c | 2009-03-03 19:30:05 -0800 | [diff] [blame] | 2329 | |
| 2330 | fp = (struct bpf_insn *)malloc(sizeof(*fp) * n); |
| 2331 | if (fp == NULL) |
Elliott Hughes | 965a4b5 | 2017-05-15 10:37:39 -0700 | [diff] [blame] | 2332 | bpf_error(cstate, "malloc"); |
The Android Open Source Project | 478ab6c | 2009-03-03 19:30:05 -0800 | [diff] [blame] | 2333 | memset((char *)fp, 0, sizeof(*fp) * n); |
Elliott Hughes | 965a4b5 | 2017-05-15 10:37:39 -0700 | [diff] [blame] | 2334 | conv_state.fstart = fp; |
| 2335 | conv_state.ftail = fp + n; |
The Android Open Source Project | 478ab6c | 2009-03-03 19:30:05 -0800 | [diff] [blame] | 2336 | |
Elliott Hughes | 965a4b5 | 2017-05-15 10:37:39 -0700 | [diff] [blame] | 2337 | unMarkAll(ic); |
| 2338 | if (convert_code_r(cstate, &conv_state, ic, root)) |
The Android Open Source Project | 478ab6c | 2009-03-03 19:30:05 -0800 | [diff] [blame] | 2339 | break; |
| 2340 | free(fp); |
| 2341 | } |
| 2342 | |
| 2343 | return fp; |
| 2344 | } |
| 2345 | |
| 2346 | /* |
| 2347 | * Make a copy of a BPF program and put it in the "fcode" member of |
| 2348 | * a "pcap_t". |
| 2349 | * |
| 2350 | * If we fail to allocate memory for the copy, fill in the "errbuf" |
| 2351 | * member of the "pcap_t" with an error message, and return -1; |
| 2352 | * otherwise, return 0. |
| 2353 | */ |
| 2354 | int |
| 2355 | install_bpf_program(pcap_t *p, struct bpf_program *fp) |
| 2356 | { |
| 2357 | size_t prog_size; |
| 2358 | |
| 2359 | /* |
JP Abgrall | 511eca3 | 2014-02-12 13:46:45 -0800 | [diff] [blame] | 2360 | * Validate the program. |
| 2361 | */ |
| 2362 | if (!bpf_validate(fp->bf_insns, fp->bf_len)) { |
Elliott Hughes | 965a4b5 | 2017-05-15 10:37:39 -0700 | [diff] [blame] | 2363 | pcap_snprintf(p->errbuf, sizeof(p->errbuf), |
JP Abgrall | 511eca3 | 2014-02-12 13:46:45 -0800 | [diff] [blame] | 2364 | "BPF program is not valid"); |
| 2365 | return (-1); |
| 2366 | } |
| 2367 | |
| 2368 | /* |
The Android Open Source Project | 478ab6c | 2009-03-03 19:30:05 -0800 | [diff] [blame] | 2369 | * Free up any already installed program. |
| 2370 | */ |
| 2371 | pcap_freecode(&p->fcode); |
| 2372 | |
| 2373 | prog_size = sizeof(*fp->bf_insns) * fp->bf_len; |
| 2374 | p->fcode.bf_len = fp->bf_len; |
| 2375 | p->fcode.bf_insns = (struct bpf_insn *)malloc(prog_size); |
| 2376 | if (p->fcode.bf_insns == NULL) { |
Haibo Huang | 165065a | 2018-07-23 17:26:52 -0700 | [diff] [blame] | 2377 | pcap_fmt_errmsg_for_errno(p->errbuf, sizeof(p->errbuf), |
| 2378 | errno, "malloc"); |
The Android Open Source Project | 478ab6c | 2009-03-03 19:30:05 -0800 | [diff] [blame] | 2379 | return (-1); |
| 2380 | } |
| 2381 | memcpy(p->fcode.bf_insns, fp->bf_insns, prog_size); |
| 2382 | return (0); |
| 2383 | } |
| 2384 | |
| 2385 | #ifdef BDEBUG |
| 2386 | static void |
Elliott Hughes | 965a4b5 | 2017-05-15 10:37:39 -0700 | [diff] [blame] | 2387 | dot_dump_node(struct icode *ic, struct block *block, struct bpf_program *prog, |
| 2388 | FILE *out) |
Elliott Hughes | d8845d7 | 2015-10-19 18:07:04 -0700 | [diff] [blame] | 2389 | { |
| 2390 | int icount, noffset; |
| 2391 | int i; |
| 2392 | |
Elliott Hughes | 965a4b5 | 2017-05-15 10:37:39 -0700 | [diff] [blame] | 2393 | if (block == NULL || isMarked(ic, block)) |
Elliott Hughes | d8845d7 | 2015-10-19 18:07:04 -0700 | [diff] [blame] | 2394 | return; |
Elliott Hughes | 965a4b5 | 2017-05-15 10:37:39 -0700 | [diff] [blame] | 2395 | Mark(ic, block); |
Elliott Hughes | d8845d7 | 2015-10-19 18:07:04 -0700 | [diff] [blame] | 2396 | |
| 2397 | icount = slength(block->stmts) + 1 + block->longjt + block->longjf; |
| 2398 | noffset = min(block->offset + icount, (int)prog->bf_len); |
| 2399 | |
| 2400 | fprintf(out, "\tblock%d [shape=ellipse, id=\"block-%d\" label=\"BLOCK%d\\n", block->id, block->id, block->id); |
| 2401 | for (i = block->offset; i < noffset; i++) { |
| 2402 | fprintf(out, "\\n%s", bpf_image(prog->bf_insns + i, i)); |
| 2403 | } |
| 2404 | fprintf(out, "\" tooltip=\""); |
| 2405 | for (i = 0; i < BPF_MEMWORDS; i++) |
Haibo Huang | 165065a | 2018-07-23 17:26:52 -0700 | [diff] [blame] | 2406 | if (block->val[i] != VAL_UNKNOWN) |
Elliott Hughes | d8845d7 | 2015-10-19 18:07:04 -0700 | [diff] [blame] | 2407 | fprintf(out, "val[%d]=%d ", i, block->val[i]); |
| 2408 | fprintf(out, "val[A]=%d ", block->val[A_ATOM]); |
| 2409 | fprintf(out, "val[X]=%d", block->val[X_ATOM]); |
| 2410 | fprintf(out, "\""); |
| 2411 | if (JT(block) == NULL) |
| 2412 | fprintf(out, ", peripheries=2"); |
| 2413 | fprintf(out, "];\n"); |
| 2414 | |
Elliott Hughes | 965a4b5 | 2017-05-15 10:37:39 -0700 | [diff] [blame] | 2415 | dot_dump_node(ic, JT(block), prog, out); |
| 2416 | dot_dump_node(ic, JF(block), prog, out); |
Elliott Hughes | d8845d7 | 2015-10-19 18:07:04 -0700 | [diff] [blame] | 2417 | } |
Elliott Hughes | 965a4b5 | 2017-05-15 10:37:39 -0700 | [diff] [blame] | 2418 | |
Elliott Hughes | d8845d7 | 2015-10-19 18:07:04 -0700 | [diff] [blame] | 2419 | static void |
Elliott Hughes | 965a4b5 | 2017-05-15 10:37:39 -0700 | [diff] [blame] | 2420 | dot_dump_edge(struct icode *ic, struct block *block, FILE *out) |
Elliott Hughes | d8845d7 | 2015-10-19 18:07:04 -0700 | [diff] [blame] | 2421 | { |
Elliott Hughes | 965a4b5 | 2017-05-15 10:37:39 -0700 | [diff] [blame] | 2422 | if (block == NULL || isMarked(ic, block)) |
Elliott Hughes | d8845d7 | 2015-10-19 18:07:04 -0700 | [diff] [blame] | 2423 | return; |
Elliott Hughes | 965a4b5 | 2017-05-15 10:37:39 -0700 | [diff] [blame] | 2424 | Mark(ic, block); |
Elliott Hughes | d8845d7 | 2015-10-19 18:07:04 -0700 | [diff] [blame] | 2425 | |
| 2426 | if (JT(block)) { |
| 2427 | fprintf(out, "\t\"block%d\":se -> \"block%d\":n [label=\"T\"]; \n", |
| 2428 | block->id, JT(block)->id); |
| 2429 | fprintf(out, "\t\"block%d\":sw -> \"block%d\":n [label=\"F\"]; \n", |
| 2430 | block->id, JF(block)->id); |
| 2431 | } |
Elliott Hughes | 965a4b5 | 2017-05-15 10:37:39 -0700 | [diff] [blame] | 2432 | dot_dump_edge(ic, JT(block), out); |
| 2433 | dot_dump_edge(ic, JF(block), out); |
Elliott Hughes | d8845d7 | 2015-10-19 18:07:04 -0700 | [diff] [blame] | 2434 | } |
Elliott Hughes | 965a4b5 | 2017-05-15 10:37:39 -0700 | [diff] [blame] | 2435 | |
Elliott Hughes | d8845d7 | 2015-10-19 18:07:04 -0700 | [diff] [blame] | 2436 | /* Output the block CFG using graphviz/DOT language |
| 2437 | * In the CFG, block's code, value index for each registers at EXIT, |
| 2438 | * and the jump relationship is show. |
| 2439 | * |
| 2440 | * example DOT for BPF `ip src host 1.1.1.1' is: |
| 2441 | digraph BPF { |
| 2442 | 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"]; |
| 2443 | 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"]; |
| 2444 | block2 [shape=ellipse, id="block-2" label="BLOCK2\n\n(004) ret #68" tooltip="val[A]=0 val[X]=0", peripheries=2]; |
| 2445 | block3 [shape=ellipse, id="block-3" label="BLOCK3\n\n(005) ret #0" tooltip="val[A]=0 val[X]=0", peripheries=2]; |
| 2446 | "block0":se -> "block1":n [label="T"]; |
| 2447 | "block0":sw -> "block3":n [label="F"]; |
| 2448 | "block1":se -> "block2":n [label="T"]; |
| 2449 | "block1":sw -> "block3":n [label="F"]; |
| 2450 | } |
| 2451 | * |
| 2452 | * After install graphviz on http://www.graphviz.org/, save it as bpf.dot |
| 2453 | * and run `dot -Tpng -O bpf.dot' to draw the graph. |
| 2454 | */ |
| 2455 | static void |
Elliott Hughes | 965a4b5 | 2017-05-15 10:37:39 -0700 | [diff] [blame] | 2456 | dot_dump(compiler_state_t *cstate, struct icode *ic) |
Elliott Hughes | d8845d7 | 2015-10-19 18:07:04 -0700 | [diff] [blame] | 2457 | { |
| 2458 | struct bpf_program f; |
| 2459 | FILE *out = stdout; |
| 2460 | |
| 2461 | memset(bids, 0, sizeof bids); |
Elliott Hughes | 965a4b5 | 2017-05-15 10:37:39 -0700 | [diff] [blame] | 2462 | f.bf_insns = icode_to_fcode(cstate, ic, ic->root, &f.bf_len); |
Elliott Hughes | d8845d7 | 2015-10-19 18:07:04 -0700 | [diff] [blame] | 2463 | |
| 2464 | fprintf(out, "digraph BPF {\n"); |
Elliott Hughes | 965a4b5 | 2017-05-15 10:37:39 -0700 | [diff] [blame] | 2465 | unMarkAll(ic); |
| 2466 | dot_dump_node(ic, ic->root, &f, out); |
Elliott Hughes | 965a4b5 | 2017-05-15 10:37:39 -0700 | [diff] [blame] | 2467 | unMarkAll(ic); |
| 2468 | dot_dump_edge(ic, ic->root, out); |
Elliott Hughes | d8845d7 | 2015-10-19 18:07:04 -0700 | [diff] [blame] | 2469 | fprintf(out, "}\n"); |
| 2470 | |
| 2471 | free((char *)f.bf_insns); |
| 2472 | } |
| 2473 | |
| 2474 | static void |
Elliott Hughes | 965a4b5 | 2017-05-15 10:37:39 -0700 | [diff] [blame] | 2475 | plain_dump(compiler_state_t *cstate, struct icode *ic) |
The Android Open Source Project | 478ab6c | 2009-03-03 19:30:05 -0800 | [diff] [blame] | 2476 | { |
| 2477 | struct bpf_program f; |
| 2478 | |
| 2479 | memset(bids, 0, sizeof bids); |
Elliott Hughes | 965a4b5 | 2017-05-15 10:37:39 -0700 | [diff] [blame] | 2480 | f.bf_insns = icode_to_fcode(cstate, ic, ic->root, &f.bf_len); |
The Android Open Source Project | 478ab6c | 2009-03-03 19:30:05 -0800 | [diff] [blame] | 2481 | bpf_dump(&f, 1); |
| 2482 | putchar('\n'); |
| 2483 | free((char *)f.bf_insns); |
| 2484 | } |
Elliott Hughes | 965a4b5 | 2017-05-15 10:37:39 -0700 | [diff] [blame] | 2485 | |
Elliott Hughes | d8845d7 | 2015-10-19 18:07:04 -0700 | [diff] [blame] | 2486 | static void |
Elliott Hughes | 965a4b5 | 2017-05-15 10:37:39 -0700 | [diff] [blame] | 2487 | opt_dump(compiler_state_t *cstate, struct icode *ic) |
Elliott Hughes | d8845d7 | 2015-10-19 18:07:04 -0700 | [diff] [blame] | 2488 | { |
Haibo Huang | 165065a | 2018-07-23 17:26:52 -0700 | [diff] [blame] | 2489 | /* |
| 2490 | * If the CFG, in DOT format, is requested, output it rather than |
| 2491 | * the code that would be generated from that graph. |
Elliott Hughes | d8845d7 | 2015-10-19 18:07:04 -0700 | [diff] [blame] | 2492 | */ |
Haibo Huang | 165065a | 2018-07-23 17:26:52 -0700 | [diff] [blame] | 2493 | if (pcap_print_dot_graph) |
Elliott Hughes | 965a4b5 | 2017-05-15 10:37:39 -0700 | [diff] [blame] | 2494 | dot_dump(cstate, ic); |
Elliott Hughes | d8845d7 | 2015-10-19 18:07:04 -0700 | [diff] [blame] | 2495 | else |
Elliott Hughes | 965a4b5 | 2017-05-15 10:37:39 -0700 | [diff] [blame] | 2496 | plain_dump(cstate, ic); |
Elliott Hughes | d8845d7 | 2015-10-19 18:07:04 -0700 | [diff] [blame] | 2497 | } |
The Android Open Source Project | 478ab6c | 2009-03-03 19:30:05 -0800 | [diff] [blame] | 2498 | #endif |