Guido van Rossum | d8faa36 | 2007-04-27 19:54:29 +0000 | [diff] [blame] | 1 | /* Peephole optimizations for bytecode compiler. */ |
Thomas Wouters | 00ee7ba | 2006-08-21 19:07:27 +0000 | [diff] [blame] | 2 | |
| 3 | #include "Python.h" |
| 4 | |
| 5 | #include "Python-ast.h" |
| 6 | #include "node.h" |
| 7 | #include "pyarena.h" |
| 8 | #include "ast.h" |
| 9 | #include "code.h" |
| 10 | #include "compile.h" |
| 11 | #include "symtable.h" |
| 12 | #include "opcode.h" |
| 13 | |
| 14 | #define GETARG(arr, i) ((int)((arr[i+2]<<8) + arr[i+1])) |
| 15 | #define UNCONDITIONAL_JUMP(op) (op==JUMP_ABSOLUTE || op==JUMP_FORWARD) |
| 16 | #define ABSOLUTE_JUMP(op) (op==JUMP_ABSOLUTE || op==CONTINUE_LOOP) |
| 17 | #define GETJUMPTGT(arr, i) (GETARG(arr,i) + (ABSOLUTE_JUMP(arr[i]) ? 0 : i+3)) |
| 18 | #define SETARG(arr, i, val) arr[i+2] = val>>8; arr[i+1] = val & 255 |
| 19 | #define CODESIZE(op) (HAS_ARG(op) ? 3 : 1) |
| 20 | #define ISBASICBLOCK(blocks, start, bytes) \ |
| 21 | (blocks[start]==blocks[start+bytes-1]) |
| 22 | |
| 23 | /* Replace LOAD_CONST c1. LOAD_CONST c2 ... LOAD_CONST cn BUILD_TUPLE n |
| 24 | with LOAD_CONST (c1, c2, ... cn). |
| 25 | The consts table must still be in list form so that the |
| 26 | new constant (c1, c2, ... cn) can be appended. |
| 27 | Called with codestr pointing to the first LOAD_CONST. |
| 28 | Bails out with no change if one or more of the LOAD_CONSTs is missing. |
| 29 | Also works for BUILD_LIST when followed by an "in" or "not in" test. |
| 30 | */ |
| 31 | static int |
Christian Heimes | cc47b05 | 2008-03-25 14:56:36 +0000 | [diff] [blame] | 32 | tuple_of_constants(unsigned char *codestr, Py_ssize_t n, PyObject *consts) |
Thomas Wouters | 00ee7ba | 2006-08-21 19:07:27 +0000 | [diff] [blame] | 33 | { |
| 34 | PyObject *newconst, *constant; |
| 35 | Py_ssize_t i, arg, len_consts; |
| 36 | |
| 37 | /* Pre-conditions */ |
| 38 | assert(PyList_CheckExact(consts)); |
| 39 | assert(codestr[n*3] == BUILD_TUPLE || codestr[n*3] == BUILD_LIST); |
| 40 | assert(GETARG(codestr, (n*3)) == n); |
| 41 | for (i=0 ; i<n ; i++) |
| 42 | assert(codestr[i*3] == LOAD_CONST); |
| 43 | |
| 44 | /* Buildup new tuple of constants */ |
| 45 | newconst = PyTuple_New(n); |
| 46 | if (newconst == NULL) |
| 47 | return 0; |
| 48 | len_consts = PyList_GET_SIZE(consts); |
| 49 | for (i=0 ; i<n ; i++) { |
| 50 | arg = GETARG(codestr, (i*3)); |
| 51 | assert(arg < len_consts); |
| 52 | constant = PyList_GET_ITEM(consts, arg); |
| 53 | Py_INCREF(constant); |
| 54 | PyTuple_SET_ITEM(newconst, i, constant); |
| 55 | } |
| 56 | |
| 57 | /* Append folded constant onto consts */ |
| 58 | if (PyList_Append(consts, newconst)) { |
| 59 | Py_DECREF(newconst); |
| 60 | return 0; |
| 61 | } |
| 62 | Py_DECREF(newconst); |
| 63 | |
| 64 | /* Write NOPs over old LOAD_CONSTS and |
| 65 | add a new LOAD_CONST newconst on top of the BUILD_TUPLE n */ |
| 66 | memset(codestr, NOP, n*3); |
| 67 | codestr[n*3] = LOAD_CONST; |
| 68 | SETARG(codestr, (n*3), len_consts); |
| 69 | return 1; |
| 70 | } |
| 71 | |
| 72 | /* Replace LOAD_CONST c1. LOAD_CONST c2 BINOP |
| 73 | with LOAD_CONST binop(c1,c2) |
| 74 | The consts table must still be in list form so that the |
| 75 | new constant can be appended. |
| 76 | Called with codestr pointing to the first LOAD_CONST. |
| 77 | Abandons the transformation if the folding fails (i.e. 1+'a'). |
| 78 | If the new constant is a sequence, only folds when the size |
| 79 | is below a threshold value. That keeps pyc files from |
| 80 | becoming large in the presence of code like: (None,)*1000. |
| 81 | */ |
| 82 | static int |
| 83 | fold_binops_on_constants(unsigned char *codestr, PyObject *consts) |
| 84 | { |
| 85 | PyObject *newconst, *v, *w; |
| 86 | Py_ssize_t len_consts, size; |
| 87 | int opcode; |
| 88 | |
| 89 | /* Pre-conditions */ |
| 90 | assert(PyList_CheckExact(consts)); |
| 91 | assert(codestr[0] == LOAD_CONST); |
| 92 | assert(codestr[3] == LOAD_CONST); |
| 93 | |
| 94 | /* Create new constant */ |
| 95 | v = PyList_GET_ITEM(consts, GETARG(codestr, 0)); |
| 96 | w = PyList_GET_ITEM(consts, GETARG(codestr, 3)); |
| 97 | opcode = codestr[6]; |
| 98 | switch (opcode) { |
| 99 | case BINARY_POWER: |
| 100 | newconst = PyNumber_Power(v, w, Py_None); |
| 101 | break; |
| 102 | case BINARY_MULTIPLY: |
| 103 | newconst = PyNumber_Multiply(v, w); |
| 104 | break; |
| 105 | case BINARY_TRUE_DIVIDE: |
| 106 | newconst = PyNumber_TrueDivide(v, w); |
| 107 | break; |
| 108 | case BINARY_FLOOR_DIVIDE: |
| 109 | newconst = PyNumber_FloorDivide(v, w); |
| 110 | break; |
| 111 | case BINARY_MODULO: |
| 112 | newconst = PyNumber_Remainder(v, w); |
| 113 | break; |
| 114 | case BINARY_ADD: |
| 115 | newconst = PyNumber_Add(v, w); |
| 116 | break; |
| 117 | case BINARY_SUBTRACT: |
| 118 | newconst = PyNumber_Subtract(v, w); |
| 119 | break; |
| 120 | case BINARY_SUBSCR: |
| 121 | newconst = PyObject_GetItem(v, w); |
| 122 | break; |
| 123 | case BINARY_LSHIFT: |
| 124 | newconst = PyNumber_Lshift(v, w); |
| 125 | break; |
| 126 | case BINARY_RSHIFT: |
| 127 | newconst = PyNumber_Rshift(v, w); |
| 128 | break; |
| 129 | case BINARY_AND: |
| 130 | newconst = PyNumber_And(v, w); |
| 131 | break; |
| 132 | case BINARY_XOR: |
| 133 | newconst = PyNumber_Xor(v, w); |
| 134 | break; |
| 135 | case BINARY_OR: |
| 136 | newconst = PyNumber_Or(v, w); |
| 137 | break; |
| 138 | default: |
| 139 | /* Called with an unknown opcode */ |
| 140 | PyErr_Format(PyExc_SystemError, |
| 141 | "unexpected binary operation %d on a constant", |
| 142 | opcode); |
| 143 | return 0; |
| 144 | } |
| 145 | if (newconst == NULL) { |
| 146 | PyErr_Clear(); |
| 147 | return 0; |
| 148 | } |
| 149 | size = PyObject_Size(newconst); |
| 150 | if (size == -1) |
| 151 | PyErr_Clear(); |
| 152 | else if (size > 20) { |
| 153 | Py_DECREF(newconst); |
| 154 | return 0; |
| 155 | } |
| 156 | |
| 157 | /* Append folded constant into consts table */ |
| 158 | len_consts = PyList_GET_SIZE(consts); |
| 159 | if (PyList_Append(consts, newconst)) { |
| 160 | Py_DECREF(newconst); |
| 161 | return 0; |
| 162 | } |
| 163 | Py_DECREF(newconst); |
| 164 | |
| 165 | /* Write NOP NOP NOP NOP LOAD_CONST newconst */ |
| 166 | memset(codestr, NOP, 4); |
| 167 | codestr[4] = LOAD_CONST; |
| 168 | SETARG(codestr, 4, len_consts); |
| 169 | return 1; |
| 170 | } |
| 171 | |
| 172 | static int |
| 173 | fold_unaryops_on_constants(unsigned char *codestr, PyObject *consts) |
| 174 | { |
| 175 | PyObject *newconst=NULL, *v; |
| 176 | Py_ssize_t len_consts; |
| 177 | int opcode; |
| 178 | |
| 179 | /* Pre-conditions */ |
| 180 | assert(PyList_CheckExact(consts)); |
| 181 | assert(codestr[0] == LOAD_CONST); |
| 182 | |
| 183 | /* Create new constant */ |
| 184 | v = PyList_GET_ITEM(consts, GETARG(codestr, 0)); |
| 185 | opcode = codestr[3]; |
| 186 | switch (opcode) { |
| 187 | case UNARY_NEGATIVE: |
| 188 | /* Preserve the sign of -0.0 */ |
| 189 | if (PyObject_IsTrue(v) == 1) |
| 190 | newconst = PyNumber_Negative(v); |
| 191 | break; |
Thomas Wouters | 00ee7ba | 2006-08-21 19:07:27 +0000 | [diff] [blame] | 192 | case UNARY_INVERT: |
| 193 | newconst = PyNumber_Invert(v); |
| 194 | break; |
| 195 | default: |
| 196 | /* Called with an unknown opcode */ |
| 197 | PyErr_Format(PyExc_SystemError, |
| 198 | "unexpected unary operation %d on a constant", |
| 199 | opcode); |
| 200 | return 0; |
| 201 | } |
| 202 | if (newconst == NULL) { |
| 203 | PyErr_Clear(); |
| 204 | return 0; |
| 205 | } |
| 206 | |
| 207 | /* Append folded constant into consts table */ |
| 208 | len_consts = PyList_GET_SIZE(consts); |
| 209 | if (PyList_Append(consts, newconst)) { |
| 210 | Py_DECREF(newconst); |
| 211 | return 0; |
| 212 | } |
| 213 | Py_DECREF(newconst); |
| 214 | |
| 215 | /* Write NOP LOAD_CONST newconst */ |
| 216 | codestr[0] = NOP; |
| 217 | codestr[1] = LOAD_CONST; |
| 218 | SETARG(codestr, 1, len_consts); |
| 219 | return 1; |
| 220 | } |
| 221 | |
| 222 | static unsigned int * |
Christian Heimes | cc47b05 | 2008-03-25 14:56:36 +0000 | [diff] [blame] | 223 | markblocks(unsigned char *code, Py_ssize_t len) |
Thomas Wouters | 00ee7ba | 2006-08-21 19:07:27 +0000 | [diff] [blame] | 224 | { |
| 225 | unsigned int *blocks = (unsigned int *)PyMem_Malloc(len*sizeof(int)); |
| 226 | int i,j, opcode, blockcnt = 0; |
| 227 | |
| 228 | if (blocks == NULL) { |
| 229 | PyErr_NoMemory(); |
| 230 | return NULL; |
| 231 | } |
| 232 | memset(blocks, 0, len*sizeof(int)); |
| 233 | |
| 234 | /* Mark labels in the first pass */ |
| 235 | for (i=0 ; i<len ; i+=CODESIZE(opcode)) { |
| 236 | opcode = code[i]; |
| 237 | switch (opcode) { |
| 238 | case FOR_ITER: |
| 239 | case JUMP_FORWARD: |
| 240 | case JUMP_IF_FALSE: |
| 241 | case JUMP_IF_TRUE: |
| 242 | case JUMP_ABSOLUTE: |
| 243 | case CONTINUE_LOOP: |
| 244 | case SETUP_LOOP: |
| 245 | case SETUP_EXCEPT: |
| 246 | case SETUP_FINALLY: |
| 247 | j = GETJUMPTGT(code, i); |
| 248 | blocks[j] = 1; |
| 249 | break; |
| 250 | } |
| 251 | } |
| 252 | /* Build block numbers in the second pass */ |
| 253 | for (i=0 ; i<len ; i++) { |
| 254 | blockcnt += blocks[i]; /* increment blockcnt over labels */ |
| 255 | blocks[i] = blockcnt; |
| 256 | } |
| 257 | return blocks; |
| 258 | } |
| 259 | |
Guido van Rossum | cd16bf6 | 2007-06-13 18:07:49 +0000 | [diff] [blame] | 260 | /* Helper to replace LOAD_NAME None/True/False with LOAD_CONST |
| 261 | Returns: 0 if no change, 1 if change, -1 if error */ |
| 262 | static int |
| 263 | load_global(unsigned char *codestr, Py_ssize_t i, char *name, PyObject *consts) |
| 264 | { |
| 265 | Py_ssize_t j; |
| 266 | PyObject *obj; |
| 267 | if (name == NULL) |
| 268 | return 0; |
| 269 | if (strcmp(name, "None") == 0) |
| 270 | obj = Py_None; |
| 271 | else if (strcmp(name, "True") == 0) |
| 272 | obj = Py_True; |
| 273 | else if (strcmp(name, "False") == 0) |
| 274 | obj = Py_False; |
| 275 | else |
| 276 | return 0; |
| 277 | for (j = 0; j < PyList_GET_SIZE(consts); j++) { |
| 278 | if (PyList_GET_ITEM(consts, j) == obj) |
| 279 | break; |
| 280 | } |
| 281 | if (j == PyList_GET_SIZE(consts)) { |
| 282 | if (PyList_Append(consts, obj) < 0) |
| 283 | return -1; |
| 284 | } |
| 285 | assert(PyList_GET_ITEM(consts, j) == obj); |
| 286 | codestr[i] = LOAD_CONST; |
| 287 | SETARG(codestr, i, j); |
| 288 | return 1; |
| 289 | } |
| 290 | |
Thomas Wouters | 00ee7ba | 2006-08-21 19:07:27 +0000 | [diff] [blame] | 291 | /* Perform basic peephole optimizations to components of a code object. |
| 292 | The consts object should still be in list form to allow new constants |
| 293 | to be appended. |
| 294 | |
Guido van Rossum | 0240b92 | 2007-02-26 21:23:50 +0000 | [diff] [blame] | 295 | To keep the optimizer simple, it bails out (does nothing) for code that |
| 296 | has a length over 32,700, and does not calculate extended arguments. |
| 297 | That allows us to avoid overflow and sign issues. Likewise, it bails when |
| 298 | the lineno table has complex encoding for gaps >= 255. EXTENDED_ARG can |
| 299 | appear before MAKE_FUNCTION; in this case both opcodes are skipped. |
| 300 | EXTENDED_ARG preceding any other opcode causes the optimizer to bail. |
Thomas Wouters | 00ee7ba | 2006-08-21 19:07:27 +0000 | [diff] [blame] | 301 | |
| 302 | Optimizations are restricted to simple transformations occuring within a |
| 303 | single basic block. All transformations keep the code size the same or |
| 304 | smaller. For those that reduce size, the gaps are initially filled with |
| 305 | NOPs. Later those NOPs are removed and the jump addresses retargeted in |
| 306 | a single pass. Line numbering is adjusted accordingly. */ |
| 307 | |
| 308 | PyObject * |
| 309 | PyCode_Optimize(PyObject *code, PyObject* consts, PyObject *names, |
| 310 | PyObject *lineno_obj) |
| 311 | { |
| 312 | Py_ssize_t i, j, codelen; |
| 313 | int nops, h, adj; |
| 314 | int tgt, tgttgt, opcode; |
| 315 | unsigned char *codestr = NULL; |
| 316 | unsigned char *lineno; |
| 317 | int *addrmap = NULL; |
| 318 | int new_line, cum_orig_line, last_line, tabsiz; |
| 319 | int cumlc=0, lastlc=0; /* Count runs of consecutive LOAD_CONSTs */ |
| 320 | unsigned int *blocks = NULL; |
| 321 | char *name; |
| 322 | |
| 323 | /* Bail out if an exception is set */ |
| 324 | if (PyErr_Occurred()) |
| 325 | goto exitUnchanged; |
| 326 | |
| 327 | /* Bypass optimization when the lineno table is too complex */ |
Christian Heimes | 72b710a | 2008-05-26 13:28:38 +0000 | [diff] [blame] | 328 | assert(PyBytes_Check(lineno_obj)); |
| 329 | lineno = (unsigned char*)PyBytes_AS_STRING(lineno_obj); |
| 330 | tabsiz = PyBytes_GET_SIZE(lineno_obj); |
Thomas Wouters | 00ee7ba | 2006-08-21 19:07:27 +0000 | [diff] [blame] | 331 | if (memchr(lineno, 255, tabsiz) != NULL) |
| 332 | goto exitUnchanged; |
| 333 | |
| 334 | /* Avoid situations where jump retargeting could overflow */ |
Christian Heimes | 72b710a | 2008-05-26 13:28:38 +0000 | [diff] [blame] | 335 | assert(PyBytes_Check(code)); |
| 336 | codelen = PyBytes_GET_SIZE(code); |
Thomas Wouters | 00ee7ba | 2006-08-21 19:07:27 +0000 | [diff] [blame] | 337 | if (codelen > 32700) |
| 338 | goto exitUnchanged; |
| 339 | |
| 340 | /* Make a modifiable copy of the code string */ |
| 341 | codestr = (unsigned char *)PyMem_Malloc(codelen); |
| 342 | if (codestr == NULL) |
| 343 | goto exitUnchanged; |
| 344 | codestr = (unsigned char *)memcpy(codestr, |
Christian Heimes | 72b710a | 2008-05-26 13:28:38 +0000 | [diff] [blame] | 345 | PyBytes_AS_STRING(code), codelen); |
Thomas Wouters | 00ee7ba | 2006-08-21 19:07:27 +0000 | [diff] [blame] | 346 | |
| 347 | /* Verify that RETURN_VALUE terminates the codestring. This allows |
| 348 | the various transformation patterns to look ahead several |
| 349 | instructions without additional checks to make sure they are not |
| 350 | looking beyond the end of the code string. |
| 351 | */ |
| 352 | if (codestr[codelen-1] != RETURN_VALUE) |
| 353 | goto exitUnchanged; |
| 354 | |
| 355 | /* Mapping to new jump targets after NOPs are removed */ |
| 356 | addrmap = (int *)PyMem_Malloc(codelen * sizeof(int)); |
| 357 | if (addrmap == NULL) |
| 358 | goto exitUnchanged; |
| 359 | |
| 360 | blocks = markblocks(codestr, codelen); |
| 361 | if (blocks == NULL) |
| 362 | goto exitUnchanged; |
| 363 | assert(PyList_Check(consts)); |
| 364 | |
| 365 | for (i=0 ; i<codelen ; i += CODESIZE(codestr[i])) { |
| 366 | opcode = codestr[i]; |
| 367 | |
| 368 | lastlc = cumlc; |
| 369 | cumlc = 0; |
| 370 | |
| 371 | switch (opcode) { |
| 372 | |
| 373 | /* Replace UNARY_NOT JUMP_IF_FALSE POP_TOP with |
| 374 | with JUMP_IF_TRUE POP_TOP */ |
| 375 | case UNARY_NOT: |
| 376 | if (codestr[i+1] != JUMP_IF_FALSE || |
| 377 | codestr[i+4] != POP_TOP || |
| 378 | !ISBASICBLOCK(blocks,i,5)) |
| 379 | continue; |
| 380 | tgt = GETJUMPTGT(codestr, (i+1)); |
| 381 | if (codestr[tgt] != POP_TOP) |
| 382 | continue; |
| 383 | j = GETARG(codestr, i+1) + 1; |
| 384 | codestr[i] = JUMP_IF_TRUE; |
| 385 | SETARG(codestr, i, j); |
| 386 | codestr[i+3] = POP_TOP; |
| 387 | codestr[i+4] = NOP; |
| 388 | break; |
| 389 | |
| 390 | /* not a is b --> a is not b |
| 391 | not a in b --> a not in b |
| 392 | not a is not b --> a is b |
| 393 | not a not in b --> a in b |
| 394 | */ |
| 395 | case COMPARE_OP: |
| 396 | j = GETARG(codestr, i); |
| 397 | if (j < 6 || j > 9 || |
| 398 | codestr[i+3] != UNARY_NOT || |
| 399 | !ISBASICBLOCK(blocks,i,4)) |
| 400 | continue; |
| 401 | SETARG(codestr, i, (j^1)); |
| 402 | codestr[i+3] = NOP; |
| 403 | break; |
| 404 | |
Guido van Rossum | cd16bf6 | 2007-06-13 18:07:49 +0000 | [diff] [blame] | 405 | /* Replace LOAD_GLOBAL/LOAD_NAME None/True/False |
| 406 | with LOAD_CONST None/True/False */ |
Thomas Wouters | 00ee7ba | 2006-08-21 19:07:27 +0000 | [diff] [blame] | 407 | case LOAD_NAME: |
| 408 | case LOAD_GLOBAL: |
| 409 | j = GETARG(codestr, i); |
Amaury Forgeot d'Arc | 39599dc | 2007-11-22 02:48:12 +0000 | [diff] [blame] | 410 | name = PyUnicode_AsString(PyTuple_GET_ITEM(names, j)); |
Guido van Rossum | cd16bf6 | 2007-06-13 18:07:49 +0000 | [diff] [blame] | 411 | h = load_global(codestr, i, name, consts); |
| 412 | if (h < 0) |
| 413 | goto exitUnchanged; |
| 414 | else if (h == 0) |
Thomas Wouters | 00ee7ba | 2006-08-21 19:07:27 +0000 | [diff] [blame] | 415 | continue; |
Guido van Rossum | d8faa36 | 2007-04-27 19:54:29 +0000 | [diff] [blame] | 416 | cumlc = lastlc + 1; |
Thomas Wouters | 00ee7ba | 2006-08-21 19:07:27 +0000 | [diff] [blame] | 417 | break; |
| 418 | |
| 419 | /* Skip over LOAD_CONST trueconst |
| 420 | JUMP_IF_FALSE xx POP_TOP */ |
| 421 | case LOAD_CONST: |
| 422 | cumlc = lastlc + 1; |
| 423 | j = GETARG(codestr, i); |
| 424 | if (codestr[i+3] != JUMP_IF_FALSE || |
| 425 | codestr[i+6] != POP_TOP || |
| 426 | !ISBASICBLOCK(blocks,i,7) || |
| 427 | !PyObject_IsTrue(PyList_GET_ITEM(consts, j))) |
| 428 | continue; |
| 429 | memset(codestr+i, NOP, 7); |
| 430 | cumlc = 0; |
| 431 | break; |
| 432 | |
| 433 | /* Try to fold tuples of constants (includes a case for lists |
| 434 | which are only used for "in" and "not in" tests). |
| 435 | Skip over BUILD_SEQN 1 UNPACK_SEQN 1. |
| 436 | Replace BUILD_SEQN 2 UNPACK_SEQN 2 with ROT2. |
| 437 | Replace BUILD_SEQN 3 UNPACK_SEQN 3 with ROT3 ROT2. */ |
| 438 | case BUILD_TUPLE: |
| 439 | case BUILD_LIST: |
| 440 | j = GETARG(codestr, i); |
| 441 | h = i - 3 * j; |
| 442 | if (h >= 0 && |
| 443 | j <= lastlc && |
| 444 | ((opcode == BUILD_TUPLE && |
| 445 | ISBASICBLOCK(blocks, h, 3*(j+1))) || |
| 446 | (opcode == BUILD_LIST && |
| 447 | codestr[i+3]==COMPARE_OP && |
| 448 | ISBASICBLOCK(blocks, h, 3*(j+2)) && |
| 449 | (GETARG(codestr,i+3)==6 || |
| 450 | GETARG(codestr,i+3)==7))) && |
| 451 | tuple_of_constants(&codestr[h], j, consts)) { |
| 452 | assert(codestr[i] == LOAD_CONST); |
| 453 | cumlc = 1; |
| 454 | break; |
| 455 | } |
| 456 | if (codestr[i+3] != UNPACK_SEQUENCE || |
| 457 | !ISBASICBLOCK(blocks,i,6) || |
| 458 | j != GETARG(codestr, i+3)) |
| 459 | continue; |
| 460 | if (j == 1) { |
| 461 | memset(codestr+i, NOP, 6); |
| 462 | } else if (j == 2) { |
| 463 | codestr[i] = ROT_TWO; |
| 464 | memset(codestr+i+1, NOP, 5); |
| 465 | } else if (j == 3) { |
| 466 | codestr[i] = ROT_THREE; |
| 467 | codestr[i+1] = ROT_TWO; |
| 468 | memset(codestr+i+2, NOP, 4); |
| 469 | } |
| 470 | break; |
| 471 | |
| 472 | /* Fold binary ops on constants. |
| 473 | LOAD_CONST c1 LOAD_CONST c2 BINOP --> LOAD_CONST binop(c1,c2) */ |
| 474 | case BINARY_POWER: |
| 475 | case BINARY_MULTIPLY: |
| 476 | case BINARY_TRUE_DIVIDE: |
| 477 | case BINARY_FLOOR_DIVIDE: |
| 478 | case BINARY_MODULO: |
| 479 | case BINARY_ADD: |
| 480 | case BINARY_SUBTRACT: |
| 481 | case BINARY_SUBSCR: |
| 482 | case BINARY_LSHIFT: |
| 483 | case BINARY_RSHIFT: |
| 484 | case BINARY_AND: |
| 485 | case BINARY_XOR: |
| 486 | case BINARY_OR: |
| 487 | if (lastlc >= 2 && |
| 488 | ISBASICBLOCK(blocks, i-6, 7) && |
| 489 | fold_binops_on_constants(&codestr[i-6], consts)) { |
| 490 | i -= 2; |
| 491 | assert(codestr[i] == LOAD_CONST); |
| 492 | cumlc = 1; |
| 493 | } |
| 494 | break; |
| 495 | |
| 496 | /* Fold unary ops on constants. |
| 497 | LOAD_CONST c1 UNARY_OP --> LOAD_CONST unary_op(c) */ |
| 498 | case UNARY_NEGATIVE: |
Thomas Wouters | 00ee7ba | 2006-08-21 19:07:27 +0000 | [diff] [blame] | 499 | case UNARY_INVERT: |
| 500 | if (lastlc >= 1 && |
| 501 | ISBASICBLOCK(blocks, i-3, 4) && |
| 502 | fold_unaryops_on_constants(&codestr[i-3], consts)) { |
| 503 | i -= 2; |
| 504 | assert(codestr[i] == LOAD_CONST); |
| 505 | cumlc = 1; |
| 506 | } |
| 507 | break; |
| 508 | |
| 509 | /* Simplify conditional jump to conditional jump where the |
| 510 | result of the first test implies the success of a similar |
| 511 | test or the failure of the opposite test. |
| 512 | Arises in code like: |
| 513 | "if a and b:" |
| 514 | "if a or b:" |
| 515 | "a and b or c" |
| 516 | "(a and b) and c" |
| 517 | x:JUMP_IF_FALSE y y:JUMP_IF_FALSE z --> x:JUMP_IF_FALSE z |
| 518 | x:JUMP_IF_FALSE y y:JUMP_IF_TRUE z --> x:JUMP_IF_FALSE y+3 |
| 519 | where y+3 is the instruction following the second test. |
| 520 | */ |
| 521 | case JUMP_IF_FALSE: |
| 522 | case JUMP_IF_TRUE: |
| 523 | tgt = GETJUMPTGT(codestr, i); |
| 524 | j = codestr[tgt]; |
| 525 | if (j == JUMP_IF_FALSE || j == JUMP_IF_TRUE) { |
| 526 | if (j == opcode) { |
| 527 | tgttgt = GETJUMPTGT(codestr, tgt) - i - 3; |
| 528 | SETARG(codestr, i, tgttgt); |
| 529 | } else { |
| 530 | tgt -= i; |
| 531 | SETARG(codestr, i, tgt); |
| 532 | } |
| 533 | break; |
| 534 | } |
| 535 | /* Intentional fallthrough */ |
| 536 | |
| 537 | /* Replace jumps to unconditional jumps */ |
| 538 | case FOR_ITER: |
| 539 | case JUMP_FORWARD: |
| 540 | case JUMP_ABSOLUTE: |
| 541 | case CONTINUE_LOOP: |
| 542 | case SETUP_LOOP: |
| 543 | case SETUP_EXCEPT: |
| 544 | case SETUP_FINALLY: |
| 545 | tgt = GETJUMPTGT(codestr, i); |
Thomas Wouters | 89f507f | 2006-12-13 04:49:30 +0000 | [diff] [blame] | 546 | /* Replace JUMP_* to a RETURN into just a RETURN */ |
| 547 | if (UNCONDITIONAL_JUMP(opcode) && |
| 548 | codestr[tgt] == RETURN_VALUE) { |
| 549 | codestr[i] = RETURN_VALUE; |
| 550 | memset(codestr+i+1, NOP, 2); |
| 551 | continue; |
| 552 | } |
Thomas Wouters | 00ee7ba | 2006-08-21 19:07:27 +0000 | [diff] [blame] | 553 | if (!UNCONDITIONAL_JUMP(codestr[tgt])) |
| 554 | continue; |
| 555 | tgttgt = GETJUMPTGT(codestr, tgt); |
| 556 | if (opcode == JUMP_FORWARD) /* JMP_ABS can go backwards */ |
| 557 | opcode = JUMP_ABSOLUTE; |
| 558 | if (!ABSOLUTE_JUMP(opcode)) |
| 559 | tgttgt -= i + 3; /* Calc relative jump addr */ |
| 560 | if (tgttgt < 0) /* No backward relative jumps */ |
| 561 | continue; |
| 562 | codestr[i] = opcode; |
| 563 | SETARG(codestr, i, tgttgt); |
| 564 | break; |
| 565 | |
| 566 | case EXTENDED_ARG: |
Guido van Rossum | 0240b92 | 2007-02-26 21:23:50 +0000 | [diff] [blame] | 567 | if (codestr[i+3] != MAKE_FUNCTION) |
| 568 | goto exitUnchanged; |
| 569 | /* don't visit MAKE_FUNCTION as GETARG will be wrong */ |
| 570 | i += 3; |
| 571 | break; |
Thomas Wouters | 00ee7ba | 2006-08-21 19:07:27 +0000 | [diff] [blame] | 572 | |
| 573 | /* Replace RETURN LOAD_CONST None RETURN with just RETURN */ |
Thomas Wouters | 89f507f | 2006-12-13 04:49:30 +0000 | [diff] [blame] | 574 | /* Remove unreachable JUMPs after RETURN */ |
Thomas Wouters | 00ee7ba | 2006-08-21 19:07:27 +0000 | [diff] [blame] | 575 | case RETURN_VALUE: |
Thomas Wouters | 89f507f | 2006-12-13 04:49:30 +0000 | [diff] [blame] | 576 | if (i+4 >= codelen) |
Thomas Wouters | 00ee7ba | 2006-08-21 19:07:27 +0000 | [diff] [blame] | 577 | continue; |
Thomas Wouters | 89f507f | 2006-12-13 04:49:30 +0000 | [diff] [blame] | 578 | if (codestr[i+4] == RETURN_VALUE && |
| 579 | ISBASICBLOCK(blocks,i,5)) |
| 580 | memset(codestr+i+1, NOP, 4); |
| 581 | else if (UNCONDITIONAL_JUMP(codestr[i+1]) && |
| 582 | ISBASICBLOCK(blocks,i,4)) |
| 583 | memset(codestr+i+1, NOP, 3); |
Thomas Wouters | 00ee7ba | 2006-08-21 19:07:27 +0000 | [diff] [blame] | 584 | break; |
| 585 | } |
| 586 | } |
| 587 | |
| 588 | /* Fixup linenotab */ |
| 589 | for (i=0, nops=0 ; i<codelen ; i += CODESIZE(codestr[i])) { |
| 590 | addrmap[i] = i - nops; |
| 591 | if (codestr[i] == NOP) |
| 592 | nops++; |
| 593 | } |
| 594 | cum_orig_line = 0; |
| 595 | last_line = 0; |
| 596 | for (i=0 ; i < tabsiz ; i+=2) { |
| 597 | cum_orig_line += lineno[i]; |
| 598 | new_line = addrmap[cum_orig_line]; |
| 599 | assert (new_line - last_line < 255); |
| 600 | lineno[i] =((unsigned char)(new_line - last_line)); |
| 601 | last_line = new_line; |
| 602 | } |
| 603 | |
| 604 | /* Remove NOPs and fixup jump targets */ |
| 605 | for (i=0, h=0 ; i<codelen ; ) { |
| 606 | opcode = codestr[i]; |
| 607 | switch (opcode) { |
| 608 | case NOP: |
| 609 | i++; |
| 610 | continue; |
| 611 | |
| 612 | case JUMP_ABSOLUTE: |
| 613 | case CONTINUE_LOOP: |
| 614 | j = addrmap[GETARG(codestr, i)]; |
| 615 | SETARG(codestr, i, j); |
| 616 | break; |
| 617 | |
| 618 | case FOR_ITER: |
| 619 | case JUMP_FORWARD: |
| 620 | case JUMP_IF_FALSE: |
| 621 | case JUMP_IF_TRUE: |
| 622 | case SETUP_LOOP: |
| 623 | case SETUP_EXCEPT: |
| 624 | case SETUP_FINALLY: |
| 625 | j = addrmap[GETARG(codestr, i) + i + 3] - addrmap[i] - 3; |
| 626 | SETARG(codestr, i, j); |
| 627 | break; |
| 628 | } |
| 629 | adj = CODESIZE(opcode); |
| 630 | while (adj--) |
| 631 | codestr[h++] = codestr[i++]; |
| 632 | } |
| 633 | assert(h + nops == codelen); |
| 634 | |
Christian Heimes | 72b710a | 2008-05-26 13:28:38 +0000 | [diff] [blame] | 635 | code = PyBytes_FromStringAndSize((char *)codestr, h); |
Thomas Wouters | 00ee7ba | 2006-08-21 19:07:27 +0000 | [diff] [blame] | 636 | PyMem_Free(addrmap); |
| 637 | PyMem_Free(codestr); |
| 638 | PyMem_Free(blocks); |
| 639 | return code; |
| 640 | |
| 641 | exitUnchanged: |
| 642 | if (blocks != NULL) |
| 643 | PyMem_Free(blocks); |
| 644 | if (addrmap != NULL) |
| 645 | PyMem_Free(addrmap); |
| 646 | if (codestr != NULL) |
| 647 | PyMem_Free(codestr); |
| 648 | Py_INCREF(code); |
| 649 | return code; |
| 650 | } |