Mercurial > hg > CbC > CbC_gcc
annotate gcc/stmt.c @ 22:0eb6cac880f0
add cbc example of quicksort.
| author | kent <kent@cr.ie.u-ryukyu.ac.jp> |
|---|---|
| date | Tue, 13 Oct 2009 17:15:58 +0900 |
| parents | 58ad6c70ea60 |
| children | 77e2b8dfacca |
| rev | line source |
|---|---|
| 0 | 1 /* Expands front end tree to back end RTL for GCC |
| 2 Copyright (C) 1987, 1988, 1989, 1992, 1993, 1994, 1995, 1996, 1997, | |
| 3 1998, 1999, 2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009 | |
| 4 Free Software Foundation, Inc. | |
| 5 | |
| 6 This file is part of GCC. | |
| 7 | |
| 8 GCC is free software; you can redistribute it and/or modify it under | |
| 9 the terms of the GNU General Public License as published by the Free | |
| 10 Software Foundation; either version 3, or (at your option) any later | |
| 11 version. | |
| 12 | |
| 13 GCC is distributed in the hope that it will be useful, but WITHOUT ANY | |
| 14 WARRANTY; without even the implied warranty of MERCHANTABILITY or | |
| 15 FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License | |
| 16 for more details. | |
| 17 | |
| 18 You should have received a copy of the GNU General Public License | |
| 19 along with GCC; see the file COPYING3. If not see | |
| 20 <http://www.gnu.org/licenses/>. */ | |
| 21 | |
| 22 /* This file handles the generation of rtl code from tree structure | |
| 23 above the level of expressions, using subroutines in exp*.c and emit-rtl.c. | |
| 24 The functions whose names start with `expand_' are called by the | |
| 25 expander to generate RTL instructions for various kinds of constructs. */ | |
| 26 | |
| 27 #include "config.h" | |
| 28 #include "system.h" | |
| 29 #include "coretypes.h" | |
| 30 #include "tm.h" | |
| 31 | |
| 32 #include "rtl.h" | |
| 33 #include "hard-reg-set.h" | |
| 34 #include "tree.h" | |
| 35 #include "tm_p.h" | |
| 36 #include "flags.h" | |
| 37 #include "except.h" | |
| 38 #include "function.h" | |
| 39 #include "insn-config.h" | |
| 40 #include "expr.h" | |
| 41 #include "libfuncs.h" | |
| 42 #include "recog.h" | |
| 43 #include "machmode.h" | |
| 44 #include "toplev.h" | |
| 45 #include "output.h" | |
| 46 #include "ggc.h" | |
| 47 #include "langhooks.h" | |
| 48 #include "predict.h" | |
| 49 #include "optabs.h" | |
| 50 #include "target.h" | |
| 51 #include "regs.h" | |
| 52 #include "alloc-pool.h" | |
| 53 | |
| 54 /* Functions and data structures for expanding case statements. */ | |
| 55 | |
| 56 /* Case label structure, used to hold info on labels within case | |
| 57 statements. We handle "range" labels; for a single-value label | |
| 58 as in C, the high and low limits are the same. | |
| 59 | |
| 60 We start with a vector of case nodes sorted in ascending order, and | |
| 61 the default label as the last element in the vector. Before expanding | |
| 62 to RTL, we transform this vector into a list linked via the RIGHT | |
| 63 fields in the case_node struct. Nodes with higher case values are | |
| 64 later in the list. | |
| 65 | |
| 66 Switch statements can be output in three forms. A branch table is | |
| 67 used if there are more than a few labels and the labels are dense | |
| 68 within the range between the smallest and largest case value. If a | |
| 69 branch table is used, no further manipulations are done with the case | |
| 70 node chain. | |
| 71 | |
| 72 The alternative to the use of a branch table is to generate a series | |
| 73 of compare and jump insns. When that is done, we use the LEFT, RIGHT, | |
| 74 and PARENT fields to hold a binary tree. Initially the tree is | |
| 75 totally unbalanced, with everything on the right. We balance the tree | |
| 76 with nodes on the left having lower case values than the parent | |
| 77 and nodes on the right having higher values. We then output the tree | |
| 78 in order. | |
| 79 | |
| 80 For very small, suitable switch statements, we can generate a series | |
| 81 of simple bit test and branches instead. */ | |
| 82 | |
| 83 struct case_node | |
| 84 { | |
| 85 struct case_node *left; /* Left son in binary tree */ | |
| 86 struct case_node *right; /* Right son in binary tree; also node chain */ | |
| 87 struct case_node *parent; /* Parent of node in binary tree */ | |
| 88 tree low; /* Lowest index value for this label */ | |
| 89 tree high; /* Highest index value for this label */ | |
| 90 tree code_label; /* Label to jump to when node matches */ | |
| 91 }; | |
| 92 | |
| 93 typedef struct case_node case_node; | |
| 94 typedef struct case_node *case_node_ptr; | |
| 95 | |
| 96 /* These are used by estimate_case_costs and balance_case_nodes. */ | |
| 97 | |
| 98 /* This must be a signed type, and non-ANSI compilers lack signed char. */ | |
| 99 static short cost_table_[129]; | |
| 100 static int use_cost_table; | |
| 101 static int cost_table_initialized; | |
| 102 | |
| 103 /* Special care is needed because we allow -1, but TREE_INT_CST_LOW | |
| 104 is unsigned. */ | |
| 105 #define COST_TABLE(I) cost_table_[(unsigned HOST_WIDE_INT) ((I) + 1)] | |
| 106 | |
| 107 static int n_occurrences (int, const char *); | |
| 108 static bool tree_conflicts_with_clobbers_p (tree, HARD_REG_SET *); | |
| 109 static void expand_nl_goto_receiver (void); | |
| 110 static bool check_operand_nalternatives (tree, tree); | |
| 111 static bool check_unique_operand_names (tree, tree); | |
| 112 static char *resolve_operand_name_1 (char *, tree, tree); | |
| 113 static void expand_null_return_1 (void); | |
| 114 static void expand_value_return (rtx); | |
| 115 static int estimate_case_costs (case_node_ptr); | |
| 116 static bool lshift_cheap_p (void); | |
| 117 static int case_bit_test_cmp (const void *, const void *); | |
| 118 static void emit_case_bit_tests (tree, tree, tree, tree, case_node_ptr, rtx); | |
| 119 static void balance_case_nodes (case_node_ptr *, case_node_ptr); | |
| 120 static int node_has_low_bound (case_node_ptr, tree); | |
| 121 static int node_has_high_bound (case_node_ptr, tree); | |
| 122 static int node_is_bounded (case_node_ptr, tree); | |
| 123 static void emit_case_nodes (rtx, case_node_ptr, rtx, tree); | |
| 124 static struct case_node *add_case_node (struct case_node *, tree, | |
| 125 tree, tree, tree, alloc_pool); | |
| 126 | |
| 127 | |
| 128 /* Return the rtx-label that corresponds to a LABEL_DECL, | |
| 129 creating it if necessary. */ | |
| 130 | |
| 131 rtx | |
| 132 label_rtx (tree label) | |
| 133 { | |
| 134 gcc_assert (TREE_CODE (label) == LABEL_DECL); | |
| 135 | |
| 136 if (!DECL_RTL_SET_P (label)) | |
| 137 { | |
| 138 rtx r = gen_label_rtx (); | |
| 139 SET_DECL_RTL (label, r); | |
| 140 if (FORCED_LABEL (label) || DECL_NONLOCAL (label)) | |
| 141 LABEL_PRESERVE_P (r) = 1; | |
| 142 } | |
| 143 | |
| 144 return DECL_RTL (label); | |
| 145 } | |
| 146 | |
| 147 /* As above, but also put it on the forced-reference list of the | |
| 148 function that contains it. */ | |
| 149 rtx | |
| 150 force_label_rtx (tree label) | |
| 151 { | |
| 152 rtx ref = label_rtx (label); | |
| 153 tree function = decl_function_context (label); | |
| 154 | |
| 155 gcc_assert (function); | |
| 156 | |
| 157 forced_labels = gen_rtx_EXPR_LIST (VOIDmode, ref, forced_labels); | |
| 158 return ref; | |
| 159 } | |
| 160 | |
| 161 /* Add an unconditional jump to LABEL as the next sequential instruction. */ | |
| 162 | |
| 163 void | |
| 164 emit_jump (rtx label) | |
| 165 { | |
| 166 do_pending_stack_adjust (); | |
| 167 emit_jump_insn (gen_jump (label)); | |
| 168 emit_barrier (); | |
| 169 } | |
| 170 | |
| 171 /* Emit code to jump to the address | |
| 172 specified by the pointer expression EXP. */ | |
| 173 | |
| 174 void | |
| 175 expand_computed_goto (tree exp) | |
| 176 { | |
| 177 rtx x = expand_normal (exp); | |
| 178 | |
| 179 x = convert_memory_address (Pmode, x); | |
| 180 | |
| 181 do_pending_stack_adjust (); | |
| 182 emit_indirect_jump (x); | |
| 183 } | |
| 184 | |
| 185 /* Handle goto statements and the labels that they can go to. */ | |
| 186 | |
| 187 /* Specify the location in the RTL code of a label LABEL, | |
| 188 which is a LABEL_DECL tree node. | |
| 189 | |
| 190 This is used for the kind of label that the user can jump to with a | |
| 191 goto statement, and for alternatives of a switch or case statement. | |
| 192 RTL labels generated for loops and conditionals don't go through here; | |
| 193 they are generated directly at the RTL level, by other functions below. | |
| 194 | |
| 195 Note that this has nothing to do with defining label *names*. | |
| 196 Languages vary in how they do that and what that even means. */ | |
| 197 | |
| 198 void | |
| 199 expand_label (tree label) | |
| 200 { | |
| 201 rtx label_r = label_rtx (label); | |
| 202 | |
| 203 do_pending_stack_adjust (); | |
| 204 emit_label (label_r); | |
| 205 if (DECL_NAME (label)) | |
| 206 LABEL_NAME (DECL_RTL (label)) = IDENTIFIER_POINTER (DECL_NAME (label)); | |
| 207 | |
| 208 if (DECL_NONLOCAL (label)) | |
| 209 { | |
| 210 expand_nl_goto_receiver (); | |
| 211 nonlocal_goto_handler_labels | |
| 212 = gen_rtx_EXPR_LIST (VOIDmode, label_r, | |
| 213 nonlocal_goto_handler_labels); | |
| 214 } | |
| 215 | |
| 216 if (FORCED_LABEL (label)) | |
| 217 forced_labels = gen_rtx_EXPR_LIST (VOIDmode, label_r, forced_labels); | |
| 218 | |
| 219 if (DECL_NONLOCAL (label) || FORCED_LABEL (label)) | |
| 220 maybe_set_first_label_num (label_r); | |
| 221 } | |
| 222 | |
| 223 /* Generate RTL code for a `goto' statement with target label LABEL. | |
| 224 LABEL should be a LABEL_DECL tree node that was or will later be | |
| 225 defined with `expand_label'. */ | |
| 226 | |
| 227 void | |
| 228 expand_goto (tree label) | |
| 229 { | |
| 230 #ifdef ENABLE_CHECKING | |
| 231 /* Check for a nonlocal goto to a containing function. Should have | |
| 232 gotten translated to __builtin_nonlocal_goto. */ | |
| 233 tree context = decl_function_context (label); | |
| 234 gcc_assert (!context || context == current_function_decl); | |
| 235 #endif | |
| 236 | |
| 237 emit_jump (label_rtx (label)); | |
| 238 } | |
| 239 | |
| 240 /* Return the number of times character C occurs in string S. */ | |
| 241 static int | |
| 242 n_occurrences (int c, const char *s) | |
| 243 { | |
| 244 int n = 0; | |
| 245 while (*s) | |
| 246 n += (*s++ == c); | |
| 247 return n; | |
| 248 } | |
| 249 | |
| 250 /* Generate RTL for an asm statement (explicit assembler code). | |
| 251 STRING is a STRING_CST node containing the assembler code text, | |
| 252 or an ADDR_EXPR containing a STRING_CST. VOL nonzero means the | |
| 253 insn is volatile; don't optimize it. */ | |
| 254 | |
| 255 static void | |
| 256 expand_asm_loc (tree string, int vol, location_t locus) | |
| 257 { | |
| 258 rtx body; | |
| 259 | |
| 260 if (TREE_CODE (string) == ADDR_EXPR) | |
| 261 string = TREE_OPERAND (string, 0); | |
| 262 | |
| 263 body = gen_rtx_ASM_INPUT_loc (VOIDmode, | |
| 264 ggc_strdup (TREE_STRING_POINTER (string)), | |
| 265 locus); | |
| 266 | |
| 267 MEM_VOLATILE_P (body) = vol; | |
| 268 | |
| 269 emit_insn (body); | |
| 270 } | |
| 271 | |
| 272 /* Parse the output constraint pointed to by *CONSTRAINT_P. It is the | |
| 273 OPERAND_NUMth output operand, indexed from zero. There are NINPUTS | |
| 274 inputs and NOUTPUTS outputs to this extended-asm. Upon return, | |
| 275 *ALLOWS_MEM will be TRUE iff the constraint allows the use of a | |
| 276 memory operand. Similarly, *ALLOWS_REG will be TRUE iff the | |
| 277 constraint allows the use of a register operand. And, *IS_INOUT | |
| 278 will be true if the operand is read-write, i.e., if it is used as | |
| 279 an input as well as an output. If *CONSTRAINT_P is not in | |
| 280 canonical form, it will be made canonical. (Note that `+' will be | |
| 281 replaced with `=' as part of this process.) | |
| 282 | |
| 283 Returns TRUE if all went well; FALSE if an error occurred. */ | |
| 284 | |
| 285 bool | |
| 286 parse_output_constraint (const char **constraint_p, int operand_num, | |
| 287 int ninputs, int noutputs, bool *allows_mem, | |
| 288 bool *allows_reg, bool *is_inout) | |
| 289 { | |
| 290 const char *constraint = *constraint_p; | |
| 291 const char *p; | |
| 292 | |
| 293 /* Assume the constraint doesn't allow the use of either a register | |
| 294 or memory. */ | |
| 295 *allows_mem = false; | |
| 296 *allows_reg = false; | |
| 297 | |
| 298 /* Allow the `=' or `+' to not be at the beginning of the string, | |
| 299 since it wasn't explicitly documented that way, and there is a | |
| 300 large body of code that puts it last. Swap the character to | |
| 301 the front, so as not to uglify any place else. */ | |
| 302 p = strchr (constraint, '='); | |
| 303 if (!p) | |
| 304 p = strchr (constraint, '+'); | |
| 305 | |
| 306 /* If the string doesn't contain an `=', issue an error | |
| 307 message. */ | |
| 308 if (!p) | |
| 309 { | |
| 310 error ("output operand constraint lacks %<=%>"); | |
| 311 return false; | |
| 312 } | |
| 313 | |
| 314 /* If the constraint begins with `+', then the operand is both read | |
| 315 from and written to. */ | |
| 316 *is_inout = (*p == '+'); | |
| 317 | |
| 318 /* Canonicalize the output constraint so that it begins with `='. */ | |
| 319 if (p != constraint || *is_inout) | |
| 320 { | |
| 321 char *buf; | |
| 322 size_t c_len = strlen (constraint); | |
| 323 | |
| 324 if (p != constraint) | |
| 325 warning (0, "output constraint %qc for operand %d " | |
| 326 "is not at the beginning", | |
| 327 *p, operand_num); | |
| 328 | |
| 329 /* Make a copy of the constraint. */ | |
| 330 buf = XALLOCAVEC (char, c_len + 1); | |
| 331 strcpy (buf, constraint); | |
| 332 /* Swap the first character and the `=' or `+'. */ | |
| 333 buf[p - constraint] = buf[0]; | |
| 334 /* Make sure the first character is an `='. (Until we do this, | |
| 335 it might be a `+'.) */ | |
| 336 buf[0] = '='; | |
| 337 /* Replace the constraint with the canonicalized string. */ | |
| 338 *constraint_p = ggc_alloc_string (buf, c_len); | |
| 339 constraint = *constraint_p; | |
| 340 } | |
| 341 | |
| 342 /* Loop through the constraint string. */ | |
| 343 for (p = constraint + 1; *p; p += CONSTRAINT_LEN (*p, p)) | |
| 344 switch (*p) | |
| 345 { | |
| 346 case '+': | |
| 347 case '=': | |
| 348 error ("operand constraint contains incorrectly positioned " | |
| 349 "%<+%> or %<=%>"); | |
| 350 return false; | |
| 351 | |
| 352 case '%': | |
| 353 if (operand_num + 1 == ninputs + noutputs) | |
| 354 { | |
| 355 error ("%<%%%> constraint used with last operand"); | |
| 356 return false; | |
| 357 } | |
| 358 break; | |
| 359 | |
| 360 case 'V': case TARGET_MEM_CONSTRAINT: case 'o': | |
| 361 *allows_mem = true; | |
| 362 break; | |
| 363 | |
| 364 case '?': case '!': case '*': case '&': case '#': | |
| 365 case 'E': case 'F': case 'G': case 'H': | |
| 366 case 's': case 'i': case 'n': | |
| 367 case 'I': case 'J': case 'K': case 'L': case 'M': | |
| 368 case 'N': case 'O': case 'P': case ',': | |
| 369 break; | |
| 370 | |
| 371 case '0': case '1': case '2': case '3': case '4': | |
| 372 case '5': case '6': case '7': case '8': case '9': | |
| 373 case '[': | |
| 374 error ("matching constraint not valid in output operand"); | |
| 375 return false; | |
| 376 | |
| 377 case '<': case '>': | |
| 378 /* ??? Before flow, auto inc/dec insns are not supposed to exist, | |
| 379 excepting those that expand_call created. So match memory | |
| 380 and hope. */ | |
| 381 *allows_mem = true; | |
| 382 break; | |
| 383 | |
| 384 case 'g': case 'X': | |
| 385 *allows_reg = true; | |
| 386 *allows_mem = true; | |
| 387 break; | |
| 388 | |
| 389 case 'p': case 'r': | |
| 390 *allows_reg = true; | |
| 391 break; | |
| 392 | |
| 393 default: | |
| 394 if (!ISALPHA (*p)) | |
| 395 break; | |
| 396 if (REG_CLASS_FROM_CONSTRAINT (*p, p) != NO_REGS) | |
| 397 *allows_reg = true; | |
| 398 #ifdef EXTRA_CONSTRAINT_STR | |
| 399 else if (EXTRA_ADDRESS_CONSTRAINT (*p, p)) | |
| 400 *allows_reg = true; | |
| 401 else if (EXTRA_MEMORY_CONSTRAINT (*p, p)) | |
| 402 *allows_mem = true; | |
| 403 else | |
| 404 { | |
| 405 /* Otherwise we can't assume anything about the nature of | |
| 406 the constraint except that it isn't purely registers. | |
| 407 Treat it like "g" and hope for the best. */ | |
| 408 *allows_reg = true; | |
| 409 *allows_mem = true; | |
| 410 } | |
| 411 #endif | |
| 412 break; | |
| 413 } | |
| 414 | |
| 415 return true; | |
| 416 } | |
| 417 | |
| 418 /* Similar, but for input constraints. */ | |
| 419 | |
| 420 bool | |
| 421 parse_input_constraint (const char **constraint_p, int input_num, | |
| 422 int ninputs, int noutputs, int ninout, | |
| 423 const char * const * constraints, | |
| 424 bool *allows_mem, bool *allows_reg) | |
| 425 { | |
| 426 const char *constraint = *constraint_p; | |
| 427 const char *orig_constraint = constraint; | |
| 428 size_t c_len = strlen (constraint); | |
| 429 size_t j; | |
| 430 bool saw_match = false; | |
| 431 | |
| 432 /* Assume the constraint doesn't allow the use of either | |
| 433 a register or memory. */ | |
| 434 *allows_mem = false; | |
| 435 *allows_reg = false; | |
| 436 | |
| 437 /* Make sure constraint has neither `=', `+', nor '&'. */ | |
| 438 | |
| 439 for (j = 0; j < c_len; j += CONSTRAINT_LEN (constraint[j], constraint+j)) | |
| 440 switch (constraint[j]) | |
| 441 { | |
| 442 case '+': case '=': case '&': | |
| 443 if (constraint == orig_constraint) | |
| 444 { | |
| 445 error ("input operand constraint contains %qc", constraint[j]); | |
| 446 return false; | |
| 447 } | |
| 448 break; | |
| 449 | |
| 450 case '%': | |
| 451 if (constraint == orig_constraint | |
| 452 && input_num + 1 == ninputs - ninout) | |
| 453 { | |
| 454 error ("%<%%%> constraint used with last operand"); | |
| 455 return false; | |
| 456 } | |
| 457 break; | |
| 458 | |
| 459 case 'V': case TARGET_MEM_CONSTRAINT: case 'o': | |
| 460 *allows_mem = true; | |
| 461 break; | |
| 462 | |
| 463 case '<': case '>': | |
| 464 case '?': case '!': case '*': case '#': | |
| 465 case 'E': case 'F': case 'G': case 'H': | |
| 466 case 's': case 'i': case 'n': | |
| 467 case 'I': case 'J': case 'K': case 'L': case 'M': | |
| 468 case 'N': case 'O': case 'P': case ',': | |
| 469 break; | |
| 470 | |
| 471 /* Whether or not a numeric constraint allows a register is | |
| 472 decided by the matching constraint, and so there is no need | |
| 473 to do anything special with them. We must handle them in | |
| 474 the default case, so that we don't unnecessarily force | |
| 475 operands to memory. */ | |
| 476 case '0': case '1': case '2': case '3': case '4': | |
| 477 case '5': case '6': case '7': case '8': case '9': | |
| 478 { | |
| 479 char *end; | |
| 480 unsigned long match; | |
| 481 | |
| 482 saw_match = true; | |
| 483 | |
| 484 match = strtoul (constraint + j, &end, 10); | |
| 485 if (match >= (unsigned long) noutputs) | |
| 486 { | |
| 487 error ("matching constraint references invalid operand number"); | |
| 488 return false; | |
| 489 } | |
| 490 | |
| 491 /* Try and find the real constraint for this dup. Only do this | |
| 492 if the matching constraint is the only alternative. */ | |
| 493 if (*end == '\0' | |
| 494 && (j == 0 || (j == 1 && constraint[0] == '%'))) | |
| 495 { | |
| 496 constraint = constraints[match]; | |
| 497 *constraint_p = constraint; | |
| 498 c_len = strlen (constraint); | |
| 499 j = 0; | |
| 500 /* ??? At the end of the loop, we will skip the first part of | |
| 501 the matched constraint. This assumes not only that the | |
| 502 other constraint is an output constraint, but also that | |
| 503 the '=' or '+' come first. */ | |
| 504 break; | |
| 505 } | |
| 506 else | |
| 507 j = end - constraint; | |
| 508 /* Anticipate increment at end of loop. */ | |
| 509 j--; | |
| 510 } | |
| 511 /* Fall through. */ | |
| 512 | |
| 513 case 'p': case 'r': | |
| 514 *allows_reg = true; | |
| 515 break; | |
| 516 | |
| 517 case 'g': case 'X': | |
| 518 *allows_reg = true; | |
| 519 *allows_mem = true; | |
| 520 break; | |
| 521 | |
| 522 default: | |
| 523 if (! ISALPHA (constraint[j])) | |
| 524 { | |
| 525 error ("invalid punctuation %qc in constraint", constraint[j]); | |
| 526 return false; | |
| 527 } | |
| 528 if (REG_CLASS_FROM_CONSTRAINT (constraint[j], constraint + j) | |
| 529 != NO_REGS) | |
| 530 *allows_reg = true; | |
| 531 #ifdef EXTRA_CONSTRAINT_STR | |
| 532 else if (EXTRA_ADDRESS_CONSTRAINT (constraint[j], constraint + j)) | |
| 533 *allows_reg = true; | |
| 534 else if (EXTRA_MEMORY_CONSTRAINT (constraint[j], constraint + j)) | |
| 535 *allows_mem = true; | |
| 536 else | |
| 537 { | |
| 538 /* Otherwise we can't assume anything about the nature of | |
| 539 the constraint except that it isn't purely registers. | |
| 540 Treat it like "g" and hope for the best. */ | |
| 541 *allows_reg = true; | |
| 542 *allows_mem = true; | |
| 543 } | |
| 544 #endif | |
| 545 break; | |
| 546 } | |
| 547 | |
| 548 if (saw_match && !*allows_reg) | |
| 549 warning (0, "matching constraint does not allow a register"); | |
| 550 | |
| 551 return true; | |
| 552 } | |
| 553 | |
| 554 /* Return DECL iff there's an overlap between *REGS and DECL, where DECL | |
| 555 can be an asm-declared register. Called via walk_tree. */ | |
| 556 | |
| 557 static tree | |
| 558 decl_overlaps_hard_reg_set_p (tree *declp, int *walk_subtrees ATTRIBUTE_UNUSED, | |
| 559 void *data) | |
| 560 { | |
| 561 tree decl = *declp; | |
| 562 const HARD_REG_SET *const regs = (const HARD_REG_SET *) data; | |
| 563 | |
| 564 if (TREE_CODE (decl) == VAR_DECL) | |
| 565 { | |
| 566 if (DECL_HARD_REGISTER (decl) | |
| 567 && REG_P (DECL_RTL (decl)) | |
| 568 && REGNO (DECL_RTL (decl)) < FIRST_PSEUDO_REGISTER) | |
| 569 { | |
| 570 rtx reg = DECL_RTL (decl); | |
| 571 | |
| 572 if (overlaps_hard_reg_set_p (*regs, GET_MODE (reg), REGNO (reg))) | |
| 573 return decl; | |
| 574 } | |
| 575 walk_subtrees = 0; | |
| 576 } | |
| 577 else if (TYPE_P (decl) || TREE_CODE (decl) == PARM_DECL) | |
| 578 walk_subtrees = 0; | |
| 579 return NULL_TREE; | |
| 580 } | |
| 581 | |
| 582 /* If there is an overlap between *REGS and DECL, return the first overlap | |
| 583 found. */ | |
| 584 tree | |
| 585 tree_overlaps_hard_reg_set (tree decl, HARD_REG_SET *regs) | |
| 586 { | |
| 587 return walk_tree (&decl, decl_overlaps_hard_reg_set_p, regs, NULL); | |
| 588 } | |
| 589 | |
| 590 /* Check for overlap between registers marked in CLOBBERED_REGS and | |
| 591 anything inappropriate in T. Emit error and return the register | |
| 592 variable definition for error, NULL_TREE for ok. */ | |
| 593 | |
| 594 static bool | |
| 595 tree_conflicts_with_clobbers_p (tree t, HARD_REG_SET *clobbered_regs) | |
| 596 { | |
| 597 /* Conflicts between asm-declared register variables and the clobber | |
| 598 list are not allowed. */ | |
| 599 tree overlap = tree_overlaps_hard_reg_set (t, clobbered_regs); | |
| 600 | |
| 601 if (overlap) | |
| 602 { | |
| 603 error ("asm-specifier for variable %qs conflicts with asm clobber list", | |
| 604 IDENTIFIER_POINTER (DECL_NAME (overlap))); | |
| 605 | |
| 606 /* Reset registerness to stop multiple errors emitted for a single | |
| 607 variable. */ | |
| 608 DECL_REGISTER (overlap) = 0; | |
| 609 return true; | |
| 610 } | |
| 611 | |
| 612 return false; | |
| 613 } | |
| 614 | |
| 615 /* Generate RTL for an asm statement with arguments. | |
| 616 STRING is the instruction template. | |
| 617 OUTPUTS is a list of output arguments (lvalues); INPUTS a list of inputs. | |
| 618 Each output or input has an expression in the TREE_VALUE and | |
| 619 a tree list in TREE_PURPOSE which in turn contains a constraint | |
| 620 name in TREE_VALUE (or NULL_TREE) and a constraint string | |
| 621 in TREE_PURPOSE. | |
| 622 CLOBBERS is a list of STRING_CST nodes each naming a hard register | |
| 623 that is clobbered by this insn. | |
| 624 | |
| 625 Not all kinds of lvalue that may appear in OUTPUTS can be stored directly. | |
| 626 Some elements of OUTPUTS may be replaced with trees representing temporary | |
| 627 values. The caller should copy those temporary values to the originally | |
| 628 specified lvalues. | |
| 629 | |
| 630 VOL nonzero means the insn is volatile; don't optimize it. */ | |
| 631 | |
| 632 static void | |
| 633 expand_asm_operands (tree string, tree outputs, tree inputs, | |
| 634 tree clobbers, int vol, location_t locus) | |
| 635 { | |
| 636 rtvec argvec, constraintvec; | |
| 637 rtx body; | |
| 638 int ninputs = list_length (inputs); | |
| 639 int noutputs = list_length (outputs); | |
| 640 int ninout; | |
| 641 int nclobbers; | |
| 642 HARD_REG_SET clobbered_regs; | |
| 643 int clobber_conflict_found = 0; | |
| 644 tree tail; | |
| 645 tree t; | |
| 646 int i; | |
| 647 /* Vector of RTX's of evaluated output operands. */ | |
| 648 rtx *output_rtx = XALLOCAVEC (rtx, noutputs); | |
| 649 int *inout_opnum = XALLOCAVEC (int, noutputs); | |
| 650 rtx *real_output_rtx = XALLOCAVEC (rtx, noutputs); | |
| 651 enum machine_mode *inout_mode = XALLOCAVEC (enum machine_mode, noutputs); | |
| 652 const char **constraints = XALLOCAVEC (const char *, noutputs + ninputs); | |
| 653 int old_generating_concat_p = generating_concat_p; | |
| 654 | |
| 655 /* An ASM with no outputs needs to be treated as volatile, for now. */ | |
| 656 if (noutputs == 0) | |
| 657 vol = 1; | |
| 658 | |
| 659 if (! check_operand_nalternatives (outputs, inputs)) | |
| 660 return; | |
| 661 | |
| 662 string = resolve_asm_operand_names (string, outputs, inputs); | |
| 663 | |
| 664 /* Collect constraints. */ | |
| 665 i = 0; | |
| 666 for (t = outputs; t ; t = TREE_CHAIN (t), i++) | |
| 667 constraints[i] = TREE_STRING_POINTER (TREE_VALUE (TREE_PURPOSE (t))); | |
| 668 for (t = inputs; t ; t = TREE_CHAIN (t), i++) | |
| 669 constraints[i] = TREE_STRING_POINTER (TREE_VALUE (TREE_PURPOSE (t))); | |
| 670 | |
| 671 /* Sometimes we wish to automatically clobber registers across an asm. | |
| 672 Case in point is when the i386 backend moved from cc0 to a hard reg -- | |
| 673 maintaining source-level compatibility means automatically clobbering | |
| 674 the flags register. */ | |
| 675 clobbers = targetm.md_asm_clobbers (outputs, inputs, clobbers); | |
| 676 | |
| 677 /* Count the number of meaningful clobbered registers, ignoring what | |
| 678 we would ignore later. */ | |
| 679 nclobbers = 0; | |
| 680 CLEAR_HARD_REG_SET (clobbered_regs); | |
| 681 for (tail = clobbers; tail; tail = TREE_CHAIN (tail)) | |
| 682 { | |
| 683 const char *regname; | |
| 684 | |
| 685 if (TREE_VALUE (tail) == error_mark_node) | |
| 686 return; | |
| 687 regname = TREE_STRING_POINTER (TREE_VALUE (tail)); | |
| 688 | |
| 689 i = decode_reg_name (regname); | |
| 690 if (i >= 0 || i == -4) | |
| 691 ++nclobbers; | |
| 692 else if (i == -2) | |
| 693 error ("unknown register name %qs in %<asm%>", regname); | |
| 694 | |
| 695 /* Mark clobbered registers. */ | |
| 696 if (i >= 0) | |
| 697 { | |
| 698 /* Clobbering the PIC register is an error. */ | |
| 699 if (i == (int) PIC_OFFSET_TABLE_REGNUM) | |
| 700 { | |
| 701 error ("PIC register %qs clobbered in %<asm%>", regname); | |
| 702 return; | |
| 703 } | |
| 704 | |
| 705 SET_HARD_REG_BIT (clobbered_regs, i); | |
| 706 } | |
| 707 } | |
| 708 | |
| 709 /* First pass over inputs and outputs checks validity and sets | |
| 710 mark_addressable if needed. */ | |
| 711 | |
| 712 ninout = 0; | |
| 713 for (i = 0, tail = outputs; tail; tail = TREE_CHAIN (tail), i++) | |
| 714 { | |
| 715 tree val = TREE_VALUE (tail); | |
| 716 tree type = TREE_TYPE (val); | |
| 717 const char *constraint; | |
| 718 bool is_inout; | |
| 719 bool allows_reg; | |
| 720 bool allows_mem; | |
| 721 | |
| 722 /* If there's an erroneous arg, emit no insn. */ | |
| 723 if (type == error_mark_node) | |
| 724 return; | |
| 725 | |
| 726 /* Try to parse the output constraint. If that fails, there's | |
| 727 no point in going further. */ | |
| 728 constraint = constraints[i]; | |
| 729 if (!parse_output_constraint (&constraint, i, ninputs, noutputs, | |
| 730 &allows_mem, &allows_reg, &is_inout)) | |
| 731 return; | |
| 732 | |
| 733 if (! allows_reg | |
| 734 && (allows_mem | |
| 735 || is_inout | |
| 736 || (DECL_P (val) | |
| 737 && REG_P (DECL_RTL (val)) | |
| 738 && GET_MODE (DECL_RTL (val)) != TYPE_MODE (type)))) | |
| 739 lang_hooks.mark_addressable (val); | |
| 740 | |
| 741 if (is_inout) | |
| 742 ninout++; | |
| 743 } | |
| 744 | |
| 745 ninputs += ninout; | |
| 746 if (ninputs + noutputs > MAX_RECOG_OPERANDS) | |
| 747 { | |
| 748 error ("more than %d operands in %<asm%>", MAX_RECOG_OPERANDS); | |
| 749 return; | |
| 750 } | |
| 751 | |
| 752 for (i = 0, tail = inputs; tail; i++, tail = TREE_CHAIN (tail)) | |
| 753 { | |
| 754 bool allows_reg, allows_mem; | |
| 755 const char *constraint; | |
| 756 | |
| 757 /* If there's an erroneous arg, emit no insn, because the ASM_INPUT | |
| 758 would get VOIDmode and that could cause a crash in reload. */ | |
| 759 if (TREE_TYPE (TREE_VALUE (tail)) == error_mark_node) | |
| 760 return; | |
| 761 | |
| 762 constraint = constraints[i + noutputs]; | |
| 763 if (! parse_input_constraint (&constraint, i, ninputs, noutputs, ninout, | |
| 764 constraints, &allows_mem, &allows_reg)) | |
| 765 return; | |
| 766 | |
| 767 if (! allows_reg && allows_mem) | |
| 768 lang_hooks.mark_addressable (TREE_VALUE (tail)); | |
| 769 } | |
| 770 | |
| 771 /* Second pass evaluates arguments. */ | |
| 772 | |
| 773 ninout = 0; | |
| 774 for (i = 0, tail = outputs; tail; tail = TREE_CHAIN (tail), i++) | |
| 775 { | |
| 776 tree val = TREE_VALUE (tail); | |
| 777 tree type = TREE_TYPE (val); | |
| 778 bool is_inout; | |
| 779 bool allows_reg; | |
| 780 bool allows_mem; | |
| 781 rtx op; | |
| 782 bool ok; | |
| 783 | |
| 784 ok = parse_output_constraint (&constraints[i], i, ninputs, | |
| 785 noutputs, &allows_mem, &allows_reg, | |
| 786 &is_inout); | |
| 787 gcc_assert (ok); | |
| 788 | |
| 789 /* If an output operand is not a decl or indirect ref and our constraint | |
| 790 allows a register, make a temporary to act as an intermediate. | |
| 791 Make the asm insn write into that, then our caller will copy it to | |
| 792 the real output operand. Likewise for promoted variables. */ | |
| 793 | |
| 794 generating_concat_p = 0; | |
| 795 | |
| 796 real_output_rtx[i] = NULL_RTX; | |
| 797 if ((TREE_CODE (val) == INDIRECT_REF | |
| 798 && allows_mem) | |
| 799 || (DECL_P (val) | |
| 800 && (allows_mem || REG_P (DECL_RTL (val))) | |
| 801 && ! (REG_P (DECL_RTL (val)) | |
| 802 && GET_MODE (DECL_RTL (val)) != TYPE_MODE (type))) | |
| 803 || ! allows_reg | |
| 804 || is_inout) | |
| 805 { | |
| 806 op = expand_expr (val, NULL_RTX, VOIDmode, EXPAND_WRITE); | |
| 807 if (MEM_P (op)) | |
| 808 op = validize_mem (op); | |
| 809 | |
| 810 if (! allows_reg && !MEM_P (op)) | |
| 811 error ("output number %d not directly addressable", i); | |
| 812 if ((! allows_mem && MEM_P (op)) | |
| 813 || GET_CODE (op) == CONCAT) | |
| 814 { | |
| 815 real_output_rtx[i] = op; | |
| 816 op = gen_reg_rtx (GET_MODE (op)); | |
| 817 if (is_inout) | |
| 818 emit_move_insn (op, real_output_rtx[i]); | |
| 819 } | |
| 820 } | |
| 821 else | |
| 822 { | |
| 823 op = assign_temp (type, 0, 0, 1); | |
| 824 op = validize_mem (op); | |
| 825 TREE_VALUE (tail) = make_tree (type, op); | |
| 826 } | |
| 827 output_rtx[i] = op; | |
| 828 | |
| 829 generating_concat_p = old_generating_concat_p; | |
| 830 | |
| 831 if (is_inout) | |
| 832 { | |
| 833 inout_mode[ninout] = TYPE_MODE (type); | |
| 834 inout_opnum[ninout++] = i; | |
| 835 } | |
| 836 | |
| 837 if (tree_conflicts_with_clobbers_p (val, &clobbered_regs)) | |
| 838 clobber_conflict_found = 1; | |
| 839 } | |
| 840 | |
| 841 /* Make vectors for the expression-rtx, constraint strings, | |
| 842 and named operands. */ | |
| 843 | |
| 844 argvec = rtvec_alloc (ninputs); | |
| 845 constraintvec = rtvec_alloc (ninputs); | |
| 846 | |
| 847 body = gen_rtx_ASM_OPERANDS ((noutputs == 0 ? VOIDmode | |
| 848 : GET_MODE (output_rtx[0])), | |
| 849 ggc_strdup (TREE_STRING_POINTER (string)), | |
| 850 empty_string, 0, argvec, constraintvec, | |
| 851 locus); | |
| 852 | |
| 853 MEM_VOLATILE_P (body) = vol; | |
| 854 | |
| 855 /* Eval the inputs and put them into ARGVEC. | |
| 856 Put their constraints into ASM_INPUTs and store in CONSTRAINTS. */ | |
| 857 | |
| 858 for (i = 0, tail = inputs; tail; tail = TREE_CHAIN (tail), ++i) | |
| 859 { | |
| 860 bool allows_reg, allows_mem; | |
| 861 const char *constraint; | |
| 862 tree val, type; | |
| 863 rtx op; | |
| 864 bool ok; | |
| 865 | |
| 866 constraint = constraints[i + noutputs]; | |
| 867 ok = parse_input_constraint (&constraint, i, ninputs, noutputs, ninout, | |
| 868 constraints, &allows_mem, &allows_reg); | |
| 869 gcc_assert (ok); | |
| 870 | |
| 871 generating_concat_p = 0; | |
| 872 | |
| 873 val = TREE_VALUE (tail); | |
| 874 type = TREE_TYPE (val); | |
| 875 /* EXPAND_INITIALIZER will not generate code for valid initializer | |
| 876 constants, but will still generate code for other types of operand. | |
| 877 This is the behavior we want for constant constraints. */ | |
| 878 op = expand_expr (val, NULL_RTX, VOIDmode, | |
| 879 allows_reg ? EXPAND_NORMAL | |
| 880 : allows_mem ? EXPAND_MEMORY | |
| 881 : EXPAND_INITIALIZER); | |
| 882 | |
| 883 /* Never pass a CONCAT to an ASM. */ | |
| 884 if (GET_CODE (op) == CONCAT) | |
| 885 op = force_reg (GET_MODE (op), op); | |
| 886 else if (MEM_P (op)) | |
| 887 op = validize_mem (op); | |
| 888 | |
| 889 if (asm_operand_ok (op, constraint, NULL) <= 0) | |
| 890 { | |
| 891 if (allows_reg && TYPE_MODE (type) != BLKmode) | |
| 892 op = force_reg (TYPE_MODE (type), op); | |
| 893 else if (!allows_mem) | |
| 894 warning (0, "asm operand %d probably doesn%'t match constraints", | |
| 895 i + noutputs); | |
| 896 else if (MEM_P (op)) | |
| 897 { | |
| 898 /* We won't recognize either volatile memory or memory | |
| 899 with a queued address as available a memory_operand | |
| 900 at this point. Ignore it: clearly this *is* a memory. */ | |
| 901 } | |
| 902 else | |
| 903 { | |
| 904 warning (0, "use of memory input without lvalue in " | |
| 905 "asm operand %d is deprecated", i + noutputs); | |
| 906 | |
| 907 if (CONSTANT_P (op)) | |
| 908 { | |
| 909 rtx mem = force_const_mem (TYPE_MODE (type), op); | |
| 910 if (mem) | |
| 911 op = validize_mem (mem); | |
| 912 else | |
| 913 op = force_reg (TYPE_MODE (type), op); | |
| 914 } | |
| 915 if (REG_P (op) | |
| 916 || GET_CODE (op) == SUBREG | |
| 917 || GET_CODE (op) == CONCAT) | |
| 918 { | |
| 919 tree qual_type = build_qualified_type (type, | |
| 920 (TYPE_QUALS (type) | |
| 921 | TYPE_QUAL_CONST)); | |
| 922 rtx memloc = assign_temp (qual_type, 1, 1, 1); | |
| 923 memloc = validize_mem (memloc); | |
| 924 emit_move_insn (memloc, op); | |
| 925 op = memloc; | |
| 926 } | |
| 927 } | |
| 928 } | |
| 929 | |
| 930 generating_concat_p = old_generating_concat_p; | |
| 931 ASM_OPERANDS_INPUT (body, i) = op; | |
| 932 | |
| 933 ASM_OPERANDS_INPUT_CONSTRAINT_EXP (body, i) | |
| 934 = gen_rtx_ASM_INPUT (TYPE_MODE (type), | |
| 935 ggc_strdup (constraints[i + noutputs])); | |
| 936 | |
| 937 if (tree_conflicts_with_clobbers_p (val, &clobbered_regs)) | |
| 938 clobber_conflict_found = 1; | |
| 939 } | |
| 940 | |
| 941 /* Protect all the operands from the queue now that they have all been | |
| 942 evaluated. */ | |
| 943 | |
| 944 generating_concat_p = 0; | |
| 945 | |
| 946 /* For in-out operands, copy output rtx to input rtx. */ | |
| 947 for (i = 0; i < ninout; i++) | |
| 948 { | |
| 949 int j = inout_opnum[i]; | |
| 950 char buffer[16]; | |
| 951 | |
| 952 ASM_OPERANDS_INPUT (body, ninputs - ninout + i) | |
| 953 = output_rtx[j]; | |
| 954 | |
| 955 sprintf (buffer, "%d", j); | |
| 956 ASM_OPERANDS_INPUT_CONSTRAINT_EXP (body, ninputs - ninout + i) | |
| 957 = gen_rtx_ASM_INPUT (inout_mode[i], ggc_strdup (buffer)); | |
| 958 } | |
| 959 | |
| 960 generating_concat_p = old_generating_concat_p; | |
| 961 | |
| 962 /* Now, for each output, construct an rtx | |
| 963 (set OUTPUT (asm_operands INSN OUTPUTCONSTRAINT OUTPUTNUMBER | |
| 964 ARGVEC CONSTRAINTS OPNAMES)) | |
| 965 If there is more than one, put them inside a PARALLEL. */ | |
| 966 | |
| 967 if (noutputs == 1 && nclobbers == 0) | |
| 968 { | |
| 969 ASM_OPERANDS_OUTPUT_CONSTRAINT (body) = ggc_strdup (constraints[0]); | |
| 970 emit_insn (gen_rtx_SET (VOIDmode, output_rtx[0], body)); | |
| 971 } | |
| 972 | |
| 973 else if (noutputs == 0 && nclobbers == 0) | |
| 974 { | |
| 975 /* No output operands: put in a raw ASM_OPERANDS rtx. */ | |
| 976 emit_insn (body); | |
| 977 } | |
| 978 | |
| 979 else | |
| 980 { | |
| 981 rtx obody = body; | |
| 982 int num = noutputs; | |
| 983 | |
| 984 if (num == 0) | |
| 985 num = 1; | |
| 986 | |
| 987 body = gen_rtx_PARALLEL (VOIDmode, rtvec_alloc (num + nclobbers)); | |
| 988 | |
| 989 /* For each output operand, store a SET. */ | |
| 990 for (i = 0, tail = outputs; tail; tail = TREE_CHAIN (tail), i++) | |
| 991 { | |
| 992 XVECEXP (body, 0, i) | |
| 993 = gen_rtx_SET (VOIDmode, | |
| 994 output_rtx[i], | |
| 995 gen_rtx_ASM_OPERANDS | |
| 996 (GET_MODE (output_rtx[i]), | |
| 997 ggc_strdup (TREE_STRING_POINTER (string)), | |
| 998 ggc_strdup (constraints[i]), | |
| 999 i, argvec, constraintvec, locus)); | |
| 1000 | |
| 1001 MEM_VOLATILE_P (SET_SRC (XVECEXP (body, 0, i))) = vol; | |
| 1002 } | |
| 1003 | |
| 1004 /* If there are no outputs (but there are some clobbers) | |
| 1005 store the bare ASM_OPERANDS into the PARALLEL. */ | |
| 1006 | |
| 1007 if (i == 0) | |
| 1008 XVECEXP (body, 0, i++) = obody; | |
| 1009 | |
| 1010 /* Store (clobber REG) for each clobbered register specified. */ | |
| 1011 | |
| 1012 for (tail = clobbers; tail; tail = TREE_CHAIN (tail)) | |
| 1013 { | |
| 1014 const char *regname = TREE_STRING_POINTER (TREE_VALUE (tail)); | |
| 1015 int j = decode_reg_name (regname); | |
| 1016 rtx clobbered_reg; | |
| 1017 | |
| 1018 if (j < 0) | |
| 1019 { | |
| 1020 if (j == -3) /* `cc', which is not a register */ | |
| 1021 continue; | |
| 1022 | |
| 1023 if (j == -4) /* `memory', don't cache memory across asm */ | |
| 1024 { | |
| 1025 XVECEXP (body, 0, i++) | |
| 1026 = gen_rtx_CLOBBER (VOIDmode, | |
| 1027 gen_rtx_MEM | |
| 1028 (BLKmode, | |
| 1029 gen_rtx_SCRATCH (VOIDmode))); | |
| 1030 continue; | |
| 1031 } | |
| 1032 | |
| 1033 /* Ignore unknown register, error already signaled. */ | |
| 1034 continue; | |
| 1035 } | |
| 1036 | |
| 1037 /* Use QImode since that's guaranteed to clobber just one reg. */ | |
| 1038 clobbered_reg = gen_rtx_REG (QImode, j); | |
| 1039 | |
| 1040 /* Do sanity check for overlap between clobbers and respectively | |
| 1041 input and outputs that hasn't been handled. Such overlap | |
| 1042 should have been detected and reported above. */ | |
| 1043 if (!clobber_conflict_found) | |
| 1044 { | |
| 1045 int opno; | |
| 1046 | |
| 1047 /* We test the old body (obody) contents to avoid tripping | |
| 1048 over the under-construction body. */ | |
| 1049 for (opno = 0; opno < noutputs; opno++) | |
| 1050 if (reg_overlap_mentioned_p (clobbered_reg, output_rtx[opno])) | |
| 1051 internal_error ("asm clobber conflict with output operand"); | |
| 1052 | |
| 1053 for (opno = 0; opno < ninputs - ninout; opno++) | |
| 1054 if (reg_overlap_mentioned_p (clobbered_reg, | |
| 1055 ASM_OPERANDS_INPUT (obody, opno))) | |
| 1056 internal_error ("asm clobber conflict with input operand"); | |
| 1057 } | |
| 1058 | |
| 1059 XVECEXP (body, 0, i++) | |
| 1060 = gen_rtx_CLOBBER (VOIDmode, clobbered_reg); | |
| 1061 } | |
| 1062 | |
| 1063 emit_insn (body); | |
| 1064 } | |
| 1065 | |
| 1066 /* For any outputs that needed reloading into registers, spill them | |
| 1067 back to where they belong. */ | |
| 1068 for (i = 0; i < noutputs; ++i) | |
| 1069 if (real_output_rtx[i]) | |
| 1070 emit_move_insn (real_output_rtx[i], output_rtx[i]); | |
| 1071 | |
| 1072 crtl->has_asm_statement = 1; | |
| 1073 free_temp_slots (); | |
| 1074 } | |
| 1075 | |
| 1076 void | |
| 1077 expand_asm_expr (tree exp) | |
| 1078 { | |
| 1079 int noutputs, i; | |
| 1080 tree outputs, tail; | |
| 1081 tree *o; | |
| 1082 | |
| 1083 if (ASM_INPUT_P (exp)) | |
| 1084 { | |
| 1085 expand_asm_loc (ASM_STRING (exp), ASM_VOLATILE_P (exp), input_location); | |
| 1086 return; | |
| 1087 } | |
| 1088 | |
| 1089 outputs = ASM_OUTPUTS (exp); | |
| 1090 noutputs = list_length (outputs); | |
| 1091 /* o[I] is the place that output number I should be written. */ | |
| 1092 o = (tree *) alloca (noutputs * sizeof (tree)); | |
| 1093 | |
| 1094 /* Record the contents of OUTPUTS before it is modified. */ | |
| 1095 for (i = 0, tail = outputs; tail; tail = TREE_CHAIN (tail), i++) | |
| 1096 o[i] = TREE_VALUE (tail); | |
| 1097 | |
| 1098 /* Generate the ASM_OPERANDS insn; store into the TREE_VALUEs of | |
| 1099 OUTPUTS some trees for where the values were actually stored. */ | |
| 1100 expand_asm_operands (ASM_STRING (exp), outputs, ASM_INPUTS (exp), | |
| 1101 ASM_CLOBBERS (exp), ASM_VOLATILE_P (exp), | |
| 1102 input_location); | |
| 1103 | |
| 1104 /* Copy all the intermediate outputs into the specified outputs. */ | |
| 1105 for (i = 0, tail = outputs; tail; tail = TREE_CHAIN (tail), i++) | |
| 1106 { | |
| 1107 if (o[i] != TREE_VALUE (tail)) | |
| 1108 { | |
| 1109 expand_assignment (o[i], TREE_VALUE (tail), false); | |
| 1110 free_temp_slots (); | |
| 1111 | |
| 1112 /* Restore the original value so that it's correct the next | |
| 1113 time we expand this function. */ | |
| 1114 TREE_VALUE (tail) = o[i]; | |
| 1115 } | |
| 1116 } | |
| 1117 } | |
| 1118 | |
| 1119 /* A subroutine of expand_asm_operands. Check that all operands have | |
| 1120 the same number of alternatives. Return true if so. */ | |
| 1121 | |
| 1122 static bool | |
| 1123 check_operand_nalternatives (tree outputs, tree inputs) | |
| 1124 { | |
| 1125 if (outputs || inputs) | |
| 1126 { | |
| 1127 tree tmp = TREE_PURPOSE (outputs ? outputs : inputs); | |
| 1128 int nalternatives | |
| 1129 = n_occurrences (',', TREE_STRING_POINTER (TREE_VALUE (tmp))); | |
| 1130 tree next = inputs; | |
| 1131 | |
| 1132 if (nalternatives + 1 > MAX_RECOG_ALTERNATIVES) | |
| 1133 { | |
| 1134 error ("too many alternatives in %<asm%>"); | |
| 1135 return false; | |
| 1136 } | |
| 1137 | |
| 1138 tmp = outputs; | |
| 1139 while (tmp) | |
| 1140 { | |
| 1141 const char *constraint | |
| 1142 = TREE_STRING_POINTER (TREE_VALUE (TREE_PURPOSE (tmp))); | |
| 1143 | |
| 1144 if (n_occurrences (',', constraint) != nalternatives) | |
| 1145 { | |
| 1146 error ("operand constraints for %<asm%> differ " | |
| 1147 "in number of alternatives"); | |
| 1148 return false; | |
| 1149 } | |
| 1150 | |
| 1151 if (TREE_CHAIN (tmp)) | |
| 1152 tmp = TREE_CHAIN (tmp); | |
| 1153 else | |
| 1154 tmp = next, next = 0; | |
| 1155 } | |
| 1156 } | |
| 1157 | |
| 1158 return true; | |
| 1159 } | |
| 1160 | |
| 1161 /* A subroutine of expand_asm_operands. Check that all operand names | |
| 1162 are unique. Return true if so. We rely on the fact that these names | |
| 1163 are identifiers, and so have been canonicalized by get_identifier, | |
| 1164 so all we need are pointer comparisons. */ | |
| 1165 | |
| 1166 static bool | |
| 1167 check_unique_operand_names (tree outputs, tree inputs) | |
| 1168 { | |
| 1169 tree i, j; | |
| 1170 | |
| 1171 for (i = outputs; i ; i = TREE_CHAIN (i)) | |
| 1172 { | |
| 1173 tree i_name = TREE_PURPOSE (TREE_PURPOSE (i)); | |
| 1174 if (! i_name) | |
| 1175 continue; | |
| 1176 | |
| 1177 for (j = TREE_CHAIN (i); j ; j = TREE_CHAIN (j)) | |
| 1178 if (simple_cst_equal (i_name, TREE_PURPOSE (TREE_PURPOSE (j)))) | |
| 1179 goto failure; | |
| 1180 } | |
| 1181 | |
| 1182 for (i = inputs; i ; i = TREE_CHAIN (i)) | |
| 1183 { | |
| 1184 tree i_name = TREE_PURPOSE (TREE_PURPOSE (i)); | |
| 1185 if (! i_name) | |
| 1186 continue; | |
| 1187 | |
| 1188 for (j = TREE_CHAIN (i); j ; j = TREE_CHAIN (j)) | |
| 1189 if (simple_cst_equal (i_name, TREE_PURPOSE (TREE_PURPOSE (j)))) | |
| 1190 goto failure; | |
| 1191 for (j = outputs; j ; j = TREE_CHAIN (j)) | |
| 1192 if (simple_cst_equal (i_name, TREE_PURPOSE (TREE_PURPOSE (j)))) | |
| 1193 goto failure; | |
| 1194 } | |
| 1195 | |
| 1196 return true; | |
| 1197 | |
| 1198 failure: | |
| 1199 error ("duplicate asm operand name %qs", | |
| 1200 TREE_STRING_POINTER (TREE_PURPOSE (TREE_PURPOSE (i)))); | |
| 1201 return false; | |
| 1202 } | |
| 1203 | |
| 1204 /* A subroutine of expand_asm_operands. Resolve the names of the operands | |
| 1205 in *POUTPUTS and *PINPUTS to numbers, and replace the name expansions in | |
| 1206 STRING and in the constraints to those numbers. */ | |
| 1207 | |
| 1208 tree | |
| 1209 resolve_asm_operand_names (tree string, tree outputs, tree inputs) | |
| 1210 { | |
| 1211 char *buffer; | |
| 1212 char *p; | |
| 1213 const char *c; | |
| 1214 tree t; | |
| 1215 | |
| 1216 check_unique_operand_names (outputs, inputs); | |
| 1217 | |
| 1218 /* Substitute [<name>] in input constraint strings. There should be no | |
| 1219 named operands in output constraints. */ | |
| 1220 for (t = inputs; t ; t = TREE_CHAIN (t)) | |
| 1221 { | |
| 1222 c = TREE_STRING_POINTER (TREE_VALUE (TREE_PURPOSE (t))); | |
| 1223 if (strchr (c, '[') != NULL) | |
| 1224 { | |
| 1225 p = buffer = xstrdup (c); | |
| 1226 while ((p = strchr (p, '[')) != NULL) | |
| 1227 p = resolve_operand_name_1 (p, outputs, inputs); | |
| 1228 TREE_VALUE (TREE_PURPOSE (t)) | |
| 1229 = build_string (strlen (buffer), buffer); | |
| 1230 free (buffer); | |
| 1231 } | |
| 1232 } | |
| 1233 | |
| 1234 /* Now check for any needed substitutions in the template. */ | |
| 1235 c = TREE_STRING_POINTER (string); | |
| 1236 while ((c = strchr (c, '%')) != NULL) | |
| 1237 { | |
| 1238 if (c[1] == '[') | |
| 1239 break; | |
| 1240 else if (ISALPHA (c[1]) && c[2] == '[') | |
| 1241 break; | |
| 1242 else | |
| 1243 { | |
| 1244 c += 1; | |
| 1245 continue; | |
| 1246 } | |
| 1247 } | |
| 1248 | |
| 1249 if (c) | |
| 1250 { | |
| 1251 /* OK, we need to make a copy so we can perform the substitutions. | |
| 1252 Assume that we will not need extra space--we get to remove '[' | |
| 1253 and ']', which means we cannot have a problem until we have more | |
| 1254 than 999 operands. */ | |
| 1255 buffer = xstrdup (TREE_STRING_POINTER (string)); | |
| 1256 p = buffer + (c - TREE_STRING_POINTER (string)); | |
| 1257 | |
| 1258 while ((p = strchr (p, '%')) != NULL) | |
| 1259 { | |
| 1260 if (p[1] == '[') | |
| 1261 p += 1; | |
| 1262 else if (ISALPHA (p[1]) && p[2] == '[') | |
| 1263 p += 2; | |
| 1264 else | |
| 1265 { | |
| 1266 p += 1; | |
| 1267 continue; | |
| 1268 } | |
| 1269 | |
| 1270 p = resolve_operand_name_1 (p, outputs, inputs); | |
| 1271 } | |
| 1272 | |
| 1273 string = build_string (strlen (buffer), buffer); | |
| 1274 free (buffer); | |
| 1275 } | |
| 1276 | |
| 1277 return string; | |
| 1278 } | |
| 1279 | |
| 1280 /* A subroutine of resolve_operand_names. P points to the '[' for a | |
| 1281 potential named operand of the form [<name>]. In place, replace | |
| 1282 the name and brackets with a number. Return a pointer to the | |
| 1283 balance of the string after substitution. */ | |
| 1284 | |
| 1285 static char * | |
| 1286 resolve_operand_name_1 (char *p, tree outputs, tree inputs) | |
| 1287 { | |
| 1288 char *q; | |
| 1289 int op; | |
| 1290 tree t; | |
| 1291 size_t len; | |
| 1292 | |
| 1293 /* Collect the operand name. */ | |
| 1294 q = strchr (p, ']'); | |
| 1295 if (!q) | |
| 1296 { | |
| 1297 error ("missing close brace for named operand"); | |
| 1298 return strchr (p, '\0'); | |
| 1299 } | |
| 1300 len = q - p - 1; | |
| 1301 | |
| 1302 /* Resolve the name to a number. */ | |
| 1303 for (op = 0, t = outputs; t ; t = TREE_CHAIN (t), op++) | |
| 1304 { | |
| 1305 tree name = TREE_PURPOSE (TREE_PURPOSE (t)); | |
| 1306 if (name) | |
| 1307 { | |
| 1308 const char *c = TREE_STRING_POINTER (name); | |
| 1309 if (strncmp (c, p + 1, len) == 0 && c[len] == '\0') | |
| 1310 goto found; | |
| 1311 } | |
| 1312 } | |
| 1313 for (t = inputs; t ; t = TREE_CHAIN (t), op++) | |
| 1314 { | |
| 1315 tree name = TREE_PURPOSE (TREE_PURPOSE (t)); | |
| 1316 if (name) | |
| 1317 { | |
| 1318 const char *c = TREE_STRING_POINTER (name); | |
| 1319 if (strncmp (c, p + 1, len) == 0 && c[len] == '\0') | |
| 1320 goto found; | |
| 1321 } | |
| 1322 } | |
| 1323 | |
| 1324 *q = '\0'; | |
| 1325 error ("undefined named operand %qs", p + 1); | |
| 1326 op = 0; | |
| 1327 found: | |
| 1328 | |
| 1329 /* Replace the name with the number. Unfortunately, not all libraries | |
| 1330 get the return value of sprintf correct, so search for the end of the | |
| 1331 generated string by hand. */ | |
| 1332 sprintf (p, "%d", op); | |
| 1333 p = strchr (p, '\0'); | |
| 1334 | |
| 1335 /* Verify the no extra buffer space assumption. */ | |
| 1336 gcc_assert (p <= q); | |
| 1337 | |
| 1338 /* Shift the rest of the buffer down to fill the gap. */ | |
| 1339 memmove (p, q + 1, strlen (q + 1) + 1); | |
| 1340 | |
| 1341 return p; | |
| 1342 } | |
| 1343 | |
| 1344 /* Generate RTL to evaluate the expression EXP. */ | |
| 1345 | |
| 1346 void | |
| 1347 expand_expr_stmt (tree exp) | |
| 1348 { | |
| 1349 rtx value; | |
| 1350 tree type; | |
| 1351 | |
| 1352 value = expand_expr (exp, const0_rtx, VOIDmode, EXPAND_NORMAL); | |
| 1353 type = TREE_TYPE (exp); | |
| 1354 | |
| 1355 /* If all we do is reference a volatile value in memory, | |
| 1356 copy it to a register to be sure it is actually touched. */ | |
| 1357 if (value && MEM_P (value) && TREE_THIS_VOLATILE (exp)) | |
| 1358 { | |
| 1359 if (TYPE_MODE (type) == VOIDmode) | |
| 1360 ; | |
| 1361 else if (TYPE_MODE (type) != BLKmode) | |
| 1362 value = copy_to_reg (value); | |
| 1363 else | |
| 1364 { | |
| 1365 rtx lab = gen_label_rtx (); | |
| 1366 | |
| 1367 /* Compare the value with itself to reference it. */ | |
| 1368 emit_cmp_and_jump_insns (value, value, EQ, | |
| 1369 expand_normal (TYPE_SIZE (type)), | |
| 1370 BLKmode, 0, lab); | |
| 1371 emit_label (lab); | |
| 1372 } | |
| 1373 } | |
| 1374 | |
| 1375 /* Free any temporaries used to evaluate this expression. */ | |
| 1376 free_temp_slots (); | |
| 1377 } | |
| 1378 | |
| 1379 /* Warn if EXP contains any computations whose results are not used. | |
| 1380 Return 1 if a warning is printed; 0 otherwise. LOCUS is the | |
| 1381 (potential) location of the expression. */ | |
| 1382 | |
| 1383 int | |
| 1384 warn_if_unused_value (const_tree exp, location_t locus) | |
| 1385 { | |
| 1386 restart: | |
| 1387 if (TREE_USED (exp) || TREE_NO_WARNING (exp)) | |
| 1388 return 0; | |
| 1389 | |
| 1390 /* Don't warn about void constructs. This includes casting to void, | |
| 1391 void function calls, and statement expressions with a final cast | |
| 1392 to void. */ | |
| 1393 if (VOID_TYPE_P (TREE_TYPE (exp))) | |
| 1394 return 0; | |
| 1395 | |
| 1396 if (EXPR_HAS_LOCATION (exp)) | |
| 1397 locus = EXPR_LOCATION (exp); | |
| 1398 | |
| 1399 switch (TREE_CODE (exp)) | |
| 1400 { | |
| 1401 case PREINCREMENT_EXPR: | |
| 1402 case POSTINCREMENT_EXPR: | |
| 1403 case PREDECREMENT_EXPR: | |
| 1404 case POSTDECREMENT_EXPR: | |
| 1405 case MODIFY_EXPR: | |
| 1406 case INIT_EXPR: | |
| 1407 case TARGET_EXPR: | |
| 1408 case CALL_EXPR: | |
| 1409 case TRY_CATCH_EXPR: | |
| 1410 case WITH_CLEANUP_EXPR: | |
| 1411 case EXIT_EXPR: | |
| 1412 case VA_ARG_EXPR: | |
| 1413 return 0; | |
| 1414 | |
| 1415 case BIND_EXPR: | |
| 1416 /* For a binding, warn if no side effect within it. */ | |
| 1417 exp = BIND_EXPR_BODY (exp); | |
| 1418 goto restart; | |
| 1419 | |
| 1420 case SAVE_EXPR: | |
|
19
58ad6c70ea60
update gcc from 4.4.0 to 4.4.1.
kent@firefly.cr.ie.u-ryukyu.ac.jp
parents:
0
diff
changeset
|
1421 case NON_LVALUE_EXPR: |
| 0 | 1422 exp = TREE_OPERAND (exp, 0); |
| 1423 goto restart; | |
| 1424 | |
| 1425 case TRUTH_ORIF_EXPR: | |
| 1426 case TRUTH_ANDIF_EXPR: | |
| 1427 /* In && or ||, warn if 2nd operand has no side effect. */ | |
| 1428 exp = TREE_OPERAND (exp, 1); | |
| 1429 goto restart; | |
| 1430 | |
| 1431 case COMPOUND_EXPR: | |
| 1432 if (warn_if_unused_value (TREE_OPERAND (exp, 0), locus)) | |
| 1433 return 1; | |
| 1434 /* Let people do `(foo (), 0)' without a warning. */ | |
| 1435 if (TREE_CONSTANT (TREE_OPERAND (exp, 1))) | |
| 1436 return 0; | |
| 1437 exp = TREE_OPERAND (exp, 1); | |
| 1438 goto restart; | |
| 1439 | |
| 1440 case COND_EXPR: | |
| 1441 /* If this is an expression with side effects, don't warn; this | |
| 1442 case commonly appears in macro expansions. */ | |
| 1443 if (TREE_SIDE_EFFECTS (exp)) | |
| 1444 return 0; | |
| 1445 goto warn; | |
| 1446 | |
| 1447 case INDIRECT_REF: | |
| 1448 /* Don't warn about automatic dereferencing of references, since | |
| 1449 the user cannot control it. */ | |
| 1450 if (TREE_CODE (TREE_TYPE (TREE_OPERAND (exp, 0))) == REFERENCE_TYPE) | |
| 1451 { | |
| 1452 exp = TREE_OPERAND (exp, 0); | |
| 1453 goto restart; | |
| 1454 } | |
| 1455 /* Fall through. */ | |
| 1456 | |
| 1457 default: | |
| 1458 /* Referencing a volatile value is a side effect, so don't warn. */ | |
| 1459 if ((DECL_P (exp) || REFERENCE_CLASS_P (exp)) | |
| 1460 && TREE_THIS_VOLATILE (exp)) | |
| 1461 return 0; | |
| 1462 | |
| 1463 /* If this is an expression which has no operands, there is no value | |
| 1464 to be unused. There are no such language-independent codes, | |
| 1465 but front ends may define such. */ | |
| 1466 if (EXPRESSION_CLASS_P (exp) && TREE_OPERAND_LENGTH (exp) == 0) | |
| 1467 return 0; | |
| 1468 | |
| 1469 warn: | |
| 1470 warning (OPT_Wunused_value, "%Hvalue computed is not used", &locus); | |
| 1471 return 1; | |
| 1472 } | |
| 1473 } | |
| 1474 | |
| 1475 | |
| 1476 /* Generate RTL to return from the current function, with no value. | |
| 1477 (That is, we do not do anything about returning any value.) */ | |
| 1478 | |
| 1479 void | |
| 1480 expand_null_return (void) | |
| 1481 { | |
| 1482 /* If this function was declared to return a value, but we | |
| 1483 didn't, clobber the return registers so that they are not | |
| 1484 propagated live to the rest of the function. */ | |
| 1485 clobber_return_register (); | |
| 1486 | |
| 1487 expand_null_return_1 (); | |
| 1488 } | |
| 1489 | |
| 1490 /* Generate RTL to return directly from the current function. | |
| 1491 (That is, we bypass any return value.) */ | |
| 1492 | |
| 1493 void | |
| 1494 expand_naked_return (void) | |
| 1495 { | |
| 1496 rtx end_label; | |
| 1497 | |
| 1498 clear_pending_stack_adjust (); | |
| 1499 do_pending_stack_adjust (); | |
| 1500 | |
| 1501 end_label = naked_return_label; | |
| 1502 if (end_label == 0) | |
| 1503 end_label = naked_return_label = gen_label_rtx (); | |
| 1504 | |
| 1505 emit_jump (end_label); | |
| 1506 } | |
| 1507 | |
| 1508 /* Generate RTL to return from the current function, with value VAL. */ | |
| 1509 | |
| 1510 static void | |
| 1511 expand_value_return (rtx val) | |
| 1512 { | |
| 1513 /* Copy the value to the return location | |
| 1514 unless it's already there. */ | |
| 1515 | |
| 1516 rtx return_reg = DECL_RTL (DECL_RESULT (current_function_decl)); | |
| 1517 if (return_reg != val) | |
| 1518 { | |
| 1519 tree type = TREE_TYPE (DECL_RESULT (current_function_decl)); | |
| 1520 if (targetm.calls.promote_function_return (TREE_TYPE (current_function_decl))) | |
| 1521 { | |
| 1522 int unsignedp = TYPE_UNSIGNED (type); | |
| 1523 enum machine_mode old_mode | |
| 1524 = DECL_MODE (DECL_RESULT (current_function_decl)); | |
| 1525 enum machine_mode mode | |
| 1526 = promote_mode (type, old_mode, &unsignedp, 1); | |
| 1527 | |
| 1528 if (mode != old_mode) | |
| 1529 val = convert_modes (mode, old_mode, val, unsignedp); | |
| 1530 } | |
| 1531 if (GET_CODE (return_reg) == PARALLEL) | |
| 1532 emit_group_load (return_reg, val, type, int_size_in_bytes (type)); | |
| 1533 else | |
| 1534 emit_move_insn (return_reg, val); | |
| 1535 } | |
| 1536 | |
| 1537 expand_null_return_1 (); | |
| 1538 } | |
| 1539 | |
| 1540 /* Output a return with no value. */ | |
| 1541 | |
| 1542 static void | |
| 1543 expand_null_return_1 (void) | |
| 1544 { | |
| 1545 clear_pending_stack_adjust (); | |
| 1546 do_pending_stack_adjust (); | |
| 1547 emit_jump (return_label); | |
| 1548 } | |
| 1549 | |
| 1550 /* Generate RTL to evaluate the expression RETVAL and return it | |
| 1551 from the current function. */ | |
| 1552 | |
| 1553 void | |
| 1554 expand_return (tree retval) | |
| 1555 { | |
| 1556 rtx result_rtl; | |
| 1557 rtx val = 0; | |
| 1558 tree retval_rhs; | |
| 1559 | |
| 1560 /* If function wants no value, give it none. */ | |
| 1561 if (TREE_CODE (TREE_TYPE (TREE_TYPE (current_function_decl))) == VOID_TYPE) | |
| 1562 { | |
| 1563 expand_normal (retval); | |
| 1564 expand_null_return (); | |
| 1565 return; | |
| 1566 } | |
| 1567 | |
| 1568 if (retval == error_mark_node) | |
| 1569 { | |
| 1570 /* Treat this like a return of no value from a function that | |
| 1571 returns a value. */ | |
| 1572 expand_null_return (); | |
| 1573 return; | |
| 1574 } | |
| 1575 else if ((TREE_CODE (retval) == MODIFY_EXPR | |
| 1576 || TREE_CODE (retval) == INIT_EXPR) | |
| 1577 && TREE_CODE (TREE_OPERAND (retval, 0)) == RESULT_DECL) | |
| 1578 retval_rhs = TREE_OPERAND (retval, 1); | |
| 1579 else | |
| 1580 retval_rhs = retval; | |
| 1581 | |
| 1582 result_rtl = DECL_RTL (DECL_RESULT (current_function_decl)); | |
| 1583 | |
| 1584 /* If we are returning the RESULT_DECL, then the value has already | |
| 1585 been stored into it, so we don't have to do anything special. */ | |
| 1586 if (TREE_CODE (retval_rhs) == RESULT_DECL) | |
| 1587 expand_value_return (result_rtl); | |
| 1588 | |
| 1589 /* If the result is an aggregate that is being returned in one (or more) | |
| 1590 registers, load the registers here. The compiler currently can't handle | |
| 1591 copying a BLKmode value into registers. We could put this code in a | |
| 1592 more general area (for use by everyone instead of just function | |
| 1593 call/return), but until this feature is generally usable it is kept here | |
| 1594 (and in expand_call). */ | |
| 1595 | |
| 1596 else if (retval_rhs != 0 | |
| 1597 && TYPE_MODE (TREE_TYPE (retval_rhs)) == BLKmode | |
| 1598 && REG_P (result_rtl)) | |
| 1599 { | |
| 1600 int i; | |
| 1601 unsigned HOST_WIDE_INT bitpos, xbitpos; | |
| 1602 unsigned HOST_WIDE_INT padding_correction = 0; | |
| 1603 unsigned HOST_WIDE_INT bytes | |
| 1604 = int_size_in_bytes (TREE_TYPE (retval_rhs)); | |
| 1605 int n_regs = (bytes + UNITS_PER_WORD - 1) / UNITS_PER_WORD; | |
| 1606 unsigned int bitsize | |
| 1607 = MIN (TYPE_ALIGN (TREE_TYPE (retval_rhs)), BITS_PER_WORD); | |
| 1608 rtx *result_pseudos = XALLOCAVEC (rtx, n_regs); | |
| 1609 rtx result_reg, src = NULL_RTX, dst = NULL_RTX; | |
| 1610 rtx result_val = expand_normal (retval_rhs); | |
| 1611 enum machine_mode tmpmode, result_reg_mode; | |
| 1612 | |
| 1613 if (bytes == 0) | |
| 1614 { | |
| 1615 expand_null_return (); | |
| 1616 return; | |
| 1617 } | |
| 1618 | |
| 1619 /* If the structure doesn't take up a whole number of words, see | |
| 1620 whether the register value should be padded on the left or on | |
| 1621 the right. Set PADDING_CORRECTION to the number of padding | |
| 1622 bits needed on the left side. | |
| 1623 | |
| 1624 In most ABIs, the structure will be returned at the least end of | |
| 1625 the register, which translates to right padding on little-endian | |
| 1626 targets and left padding on big-endian targets. The opposite | |
| 1627 holds if the structure is returned at the most significant | |
| 1628 end of the register. */ | |
| 1629 if (bytes % UNITS_PER_WORD != 0 | |
| 1630 && (targetm.calls.return_in_msb (TREE_TYPE (retval_rhs)) | |
| 1631 ? !BYTES_BIG_ENDIAN | |
| 1632 : BYTES_BIG_ENDIAN)) | |
| 1633 padding_correction = (BITS_PER_WORD - ((bytes % UNITS_PER_WORD) | |
| 1634 * BITS_PER_UNIT)); | |
| 1635 | |
| 1636 /* Copy the structure BITSIZE bits at a time. */ | |
| 1637 for (bitpos = 0, xbitpos = padding_correction; | |
| 1638 bitpos < bytes * BITS_PER_UNIT; | |
| 1639 bitpos += bitsize, xbitpos += bitsize) | |
| 1640 { | |
| 1641 /* We need a new destination pseudo each time xbitpos is | |
| 1642 on a word boundary and when xbitpos == padding_correction | |
| 1643 (the first time through). */ | |
| 1644 if (xbitpos % BITS_PER_WORD == 0 | |
| 1645 || xbitpos == padding_correction) | |
| 1646 { | |
| 1647 /* Generate an appropriate register. */ | |
| 1648 dst = gen_reg_rtx (word_mode); | |
| 1649 result_pseudos[xbitpos / BITS_PER_WORD] = dst; | |
| 1650 | |
| 1651 /* Clear the destination before we move anything into it. */ | |
| 1652 emit_move_insn (dst, CONST0_RTX (GET_MODE (dst))); | |
| 1653 } | |
| 1654 | |
| 1655 /* We need a new source operand each time bitpos is on a word | |
| 1656 boundary. */ | |
| 1657 if (bitpos % BITS_PER_WORD == 0) | |
| 1658 src = operand_subword_force (result_val, | |
| 1659 bitpos / BITS_PER_WORD, | |
| 1660 BLKmode); | |
| 1661 | |
| 1662 /* Use bitpos for the source extraction (left justified) and | |
| 1663 xbitpos for the destination store (right justified). */ | |
| 1664 store_bit_field (dst, bitsize, xbitpos % BITS_PER_WORD, word_mode, | |
| 1665 extract_bit_field (src, bitsize, | |
| 1666 bitpos % BITS_PER_WORD, 1, | |
| 1667 NULL_RTX, word_mode, word_mode)); | |
| 1668 } | |
| 1669 | |
| 1670 tmpmode = GET_MODE (result_rtl); | |
| 1671 if (tmpmode == BLKmode) | |
| 1672 { | |
| 1673 /* Find the smallest integer mode large enough to hold the | |
| 1674 entire structure and use that mode instead of BLKmode | |
| 1675 on the USE insn for the return register. */ | |
| 1676 for (tmpmode = GET_CLASS_NARROWEST_MODE (MODE_INT); | |
| 1677 tmpmode != VOIDmode; | |
| 1678 tmpmode = GET_MODE_WIDER_MODE (tmpmode)) | |
| 1679 /* Have we found a large enough mode? */ | |
| 1680 if (GET_MODE_SIZE (tmpmode) >= bytes) | |
| 1681 break; | |
| 1682 | |
| 1683 /* A suitable mode should have been found. */ | |
| 1684 gcc_assert (tmpmode != VOIDmode); | |
| 1685 | |
| 1686 PUT_MODE (result_rtl, tmpmode); | |
| 1687 } | |
| 1688 | |
| 1689 if (GET_MODE_SIZE (tmpmode) < GET_MODE_SIZE (word_mode)) | |
| 1690 result_reg_mode = word_mode; | |
| 1691 else | |
| 1692 result_reg_mode = tmpmode; | |
| 1693 result_reg = gen_reg_rtx (result_reg_mode); | |
| 1694 | |
| 1695 for (i = 0; i < n_regs; i++) | |
| 1696 emit_move_insn (operand_subword (result_reg, i, 0, result_reg_mode), | |
| 1697 result_pseudos[i]); | |
| 1698 | |
| 1699 if (tmpmode != result_reg_mode) | |
| 1700 result_reg = gen_lowpart (tmpmode, result_reg); | |
| 1701 | |
| 1702 expand_value_return (result_reg); | |
| 1703 } | |
| 1704 else if (retval_rhs != 0 | |
| 1705 && !VOID_TYPE_P (TREE_TYPE (retval_rhs)) | |
| 1706 && (REG_P (result_rtl) | |
| 1707 || (GET_CODE (result_rtl) == PARALLEL))) | |
| 1708 { | |
| 1709 /* Calculate the return value into a temporary (usually a pseudo | |
| 1710 reg). */ | |
| 1711 tree ot = TREE_TYPE (DECL_RESULT (current_function_decl)); | |
| 1712 tree nt = build_qualified_type (ot, TYPE_QUALS (ot) | TYPE_QUAL_CONST); | |
| 1713 | |
| 1714 val = assign_temp (nt, 0, 0, 1); | |
| 1715 val = expand_expr (retval_rhs, val, GET_MODE (val), EXPAND_NORMAL); | |
| 1716 val = force_not_mem (val); | |
| 1717 /* Return the calculated value. */ | |
| 1718 expand_value_return (val); | |
| 1719 } | |
| 1720 else | |
| 1721 { | |
| 1722 /* No hard reg used; calculate value into hard return reg. */ | |
| 1723 expand_expr (retval, const0_rtx, VOIDmode, EXPAND_NORMAL); | |
| 1724 expand_value_return (result_rtl); | |
| 1725 } | |
| 1726 } | |
| 1727 | |
| 1728 /* Emit code to restore vital registers at the beginning of a nonlocal goto | |
| 1729 handler. */ | |
| 1730 static void | |
| 1731 expand_nl_goto_receiver (void) | |
| 1732 { | |
| 1733 /* Clobber the FP when we get here, so we have to make sure it's | |
| 1734 marked as used by this function. */ | |
| 1735 emit_use (hard_frame_pointer_rtx); | |
| 1736 | |
| 1737 /* Mark the static chain as clobbered here so life information | |
| 1738 doesn't get messed up for it. */ | |
| 1739 emit_clobber (static_chain_rtx); | |
| 1740 | |
| 1741 #ifdef HAVE_nonlocal_goto | |
| 1742 if (! HAVE_nonlocal_goto) | |
| 1743 #endif | |
| 1744 /* First adjust our frame pointer to its actual value. It was | |
| 1745 previously set to the start of the virtual area corresponding to | |
| 1746 the stacked variables when we branched here and now needs to be | |
| 1747 adjusted to the actual hardware fp value. | |
| 1748 | |
| 1749 Assignments are to virtual registers are converted by | |
| 1750 instantiate_virtual_regs into the corresponding assignment | |
| 1751 to the underlying register (fp in this case) that makes | |
| 1752 the original assignment true. | |
| 1753 So the following insn will actually be | |
| 1754 decrementing fp by STARTING_FRAME_OFFSET. */ | |
| 1755 emit_move_insn (virtual_stack_vars_rtx, hard_frame_pointer_rtx); | |
| 1756 | |
| 1757 #if ARG_POINTER_REGNUM != HARD_FRAME_POINTER_REGNUM | |
| 1758 if (fixed_regs[ARG_POINTER_REGNUM]) | |
| 1759 { | |
| 1760 #ifdef ELIMINABLE_REGS | |
| 1761 /* If the argument pointer can be eliminated in favor of the | |
| 1762 frame pointer, we don't need to restore it. We assume here | |
| 1763 that if such an elimination is present, it can always be used. | |
| 1764 This is the case on all known machines; if we don't make this | |
| 1765 assumption, we do unnecessary saving on many machines. */ | |
| 1766 static const struct elims {const int from, to;} elim_regs[] = ELIMINABLE_REGS; | |
| 1767 size_t i; | |
| 1768 | |
| 1769 for (i = 0; i < ARRAY_SIZE (elim_regs); i++) | |
| 1770 if (elim_regs[i].from == ARG_POINTER_REGNUM | |
| 1771 && elim_regs[i].to == HARD_FRAME_POINTER_REGNUM) | |
| 1772 break; | |
| 1773 | |
| 1774 if (i == ARRAY_SIZE (elim_regs)) | |
| 1775 #endif | |
| 1776 { | |
| 1777 /* Now restore our arg pointer from the address at which it | |
| 1778 was saved in our stack frame. */ | |
| 1779 emit_move_insn (crtl->args.internal_arg_pointer, | |
| 1780 copy_to_reg (get_arg_pointer_save_area ())); | |
| 1781 } | |
| 1782 } | |
| 1783 #endif | |
| 1784 | |
| 1785 #ifdef HAVE_nonlocal_goto_receiver | |
| 1786 if (HAVE_nonlocal_goto_receiver) | |
| 1787 emit_insn (gen_nonlocal_goto_receiver ()); | |
| 1788 #endif | |
| 1789 | |
| 1790 /* We must not allow the code we just generated to be reordered by | |
| 1791 scheduling. Specifically, the update of the frame pointer must | |
| 1792 happen immediately, not later. */ | |
| 1793 emit_insn (gen_blockage ()); | |
| 1794 } | |
| 1795 | |
| 1796 /* Generate RTL for the automatic variable declaration DECL. | |
| 1797 (Other kinds of declarations are simply ignored if seen here.) */ | |
| 1798 | |
| 1799 void | |
| 1800 expand_decl (tree decl) | |
| 1801 { | |
| 1802 tree type; | |
| 1803 | |
| 1804 type = TREE_TYPE (decl); | |
| 1805 | |
| 1806 /* For a CONST_DECL, set mode, alignment, and sizes from those of the | |
| 1807 type in case this node is used in a reference. */ | |
| 1808 if (TREE_CODE (decl) == CONST_DECL) | |
| 1809 { | |
| 1810 DECL_MODE (decl) = TYPE_MODE (type); | |
| 1811 DECL_ALIGN (decl) = TYPE_ALIGN (type); | |
| 1812 DECL_SIZE (decl) = TYPE_SIZE (type); | |
| 1813 DECL_SIZE_UNIT (decl) = TYPE_SIZE_UNIT (type); | |
| 1814 return; | |
| 1815 } | |
| 1816 | |
| 1817 /* Otherwise, only automatic variables need any expansion done. Static and | |
| 1818 external variables, and external functions, will be handled by | |
| 1819 `assemble_variable' (called from finish_decl). TYPE_DECL requires | |
| 1820 nothing. PARM_DECLs are handled in `assign_parms'. */ | |
| 1821 if (TREE_CODE (decl) != VAR_DECL) | |
| 1822 return; | |
| 1823 | |
| 1824 if (TREE_STATIC (decl) || DECL_EXTERNAL (decl)) | |
| 1825 return; | |
| 1826 | |
| 1827 /* Create the RTL representation for the variable. */ | |
| 1828 | |
| 1829 if (type == error_mark_node) | |
| 1830 SET_DECL_RTL (decl, gen_rtx_MEM (BLKmode, const0_rtx)); | |
| 1831 | |
| 1832 else if (DECL_SIZE (decl) == 0) | |
| 1833 { | |
| 1834 /* Variable with incomplete type. */ | |
| 1835 rtx x; | |
| 1836 if (DECL_INITIAL (decl) == 0) | |
| 1837 /* Error message was already done; now avoid a crash. */ | |
| 1838 x = gen_rtx_MEM (BLKmode, const0_rtx); | |
| 1839 else | |
| 1840 /* An initializer is going to decide the size of this array. | |
| 1841 Until we know the size, represent its address with a reg. */ | |
| 1842 x = gen_rtx_MEM (BLKmode, gen_reg_rtx (Pmode)); | |
| 1843 | |
| 1844 set_mem_attributes (x, decl, 1); | |
| 1845 SET_DECL_RTL (decl, x); | |
| 1846 } | |
| 1847 else if (use_register_for_decl (decl)) | |
| 1848 { | |
| 1849 /* Automatic variable that can go in a register. */ | |
| 1850 int unsignedp = TYPE_UNSIGNED (type); | |
| 1851 enum machine_mode reg_mode | |
| 1852 = promote_mode (type, DECL_MODE (decl), &unsignedp, 0); | |
| 1853 | |
| 1854 SET_DECL_RTL (decl, gen_reg_rtx (reg_mode)); | |
| 1855 | |
| 1856 /* Note if the object is a user variable. */ | |
| 1857 if (!DECL_ARTIFICIAL (decl)) | |
| 1858 mark_user_reg (DECL_RTL (decl)); | |
| 1859 | |
| 1860 if (POINTER_TYPE_P (type)) | |
| 1861 mark_reg_pointer (DECL_RTL (decl), | |
| 1862 TYPE_ALIGN (TREE_TYPE (TREE_TYPE (decl)))); | |
| 1863 } | |
| 1864 | |
| 1865 else | |
| 1866 { | |
| 1867 rtx oldaddr = 0; | |
| 1868 rtx addr; | |
| 1869 rtx x; | |
| 1870 | |
| 1871 /* Variable-sized decls are dealt with in the gimplifier. */ | |
| 1872 gcc_assert (TREE_CODE (DECL_SIZE_UNIT (decl)) == INTEGER_CST); | |
| 1873 | |
| 1874 /* If we previously made RTL for this decl, it must be an array | |
| 1875 whose size was determined by the initializer. | |
| 1876 The old address was a register; set that register now | |
| 1877 to the proper address. */ | |
| 1878 if (DECL_RTL_SET_P (decl)) | |
| 1879 { | |
| 1880 gcc_assert (MEM_P (DECL_RTL (decl))); | |
| 1881 gcc_assert (REG_P (XEXP (DECL_RTL (decl), 0))); | |
| 1882 oldaddr = XEXP (DECL_RTL (decl), 0); | |
| 1883 } | |
| 1884 | |
| 1885 /* Set alignment we actually gave this decl. */ | |
| 1886 DECL_ALIGN (decl) = (DECL_MODE (decl) == BLKmode ? BIGGEST_ALIGNMENT | |
| 1887 : GET_MODE_BITSIZE (DECL_MODE (decl))); | |
| 1888 DECL_USER_ALIGN (decl) = 0; | |
| 1889 | |
| 1890 x = assign_temp (decl, 1, 1, 1); | |
| 1891 set_mem_attributes (x, decl, 1); | |
| 1892 SET_DECL_RTL (decl, x); | |
| 1893 | |
| 1894 if (oldaddr) | |
| 1895 { | |
| 1896 addr = force_operand (XEXP (DECL_RTL (decl), 0), oldaddr); | |
| 1897 if (addr != oldaddr) | |
| 1898 emit_move_insn (oldaddr, addr); | |
| 1899 } | |
| 1900 } | |
| 1901 } | |
| 1902 | |
| 1903 /* Emit code to save the current value of stack. */ | |
| 1904 rtx | |
| 1905 expand_stack_save (void) | |
| 1906 { | |
| 1907 rtx ret = NULL_RTX; | |
| 1908 | |
| 1909 do_pending_stack_adjust (); | |
| 1910 emit_stack_save (SAVE_BLOCK, &ret, NULL_RTX); | |
| 1911 return ret; | |
| 1912 } | |
| 1913 | |
| 1914 /* Emit code to restore the current value of stack. */ | |
| 1915 void | |
| 1916 expand_stack_restore (tree var) | |
| 1917 { | |
| 1918 rtx sa = expand_normal (var); | |
| 1919 | |
| 1920 sa = convert_memory_address (Pmode, sa); | |
| 1921 emit_stack_restore (SAVE_BLOCK, sa, NULL_RTX); | |
| 1922 } | |
| 1923 | |
| 1924 /* Do the insertion of a case label into case_list. The labels are | |
| 1925 fed to us in descending order from the sorted vector of case labels used | |
| 1926 in the tree part of the middle end. So the list we construct is | |
| 1927 sorted in ascending order. The bounds on the case range, LOW and HIGH, | |
| 1928 are converted to case's index type TYPE. */ | |
| 1929 | |
| 1930 static struct case_node * | |
| 1931 add_case_node (struct case_node *head, tree type, tree low, tree high, | |
| 1932 tree label, alloc_pool case_node_pool) | |
| 1933 { | |
| 1934 tree min_value, max_value; | |
| 1935 struct case_node *r; | |
| 1936 | |
| 1937 gcc_assert (TREE_CODE (low) == INTEGER_CST); | |
| 1938 gcc_assert (!high || TREE_CODE (high) == INTEGER_CST); | |
| 1939 | |
| 1940 min_value = TYPE_MIN_VALUE (type); | |
| 1941 max_value = TYPE_MAX_VALUE (type); | |
| 1942 | |
| 1943 /* If there's no HIGH value, then this is not a case range; it's | |
| 1944 just a simple case label. But that's just a degenerate case | |
| 1945 range. | |
| 1946 If the bounds are equal, turn this into the one-value case. */ | |
| 1947 if (!high || tree_int_cst_equal (low, high)) | |
| 1948 { | |
| 1949 /* If the simple case value is unreachable, ignore it. */ | |
| 1950 if ((TREE_CODE (min_value) == INTEGER_CST | |
| 1951 && tree_int_cst_compare (low, min_value) < 0) | |
| 1952 || (TREE_CODE (max_value) == INTEGER_CST | |
| 1953 && tree_int_cst_compare (low, max_value) > 0)) | |
| 1954 return head; | |
| 1955 low = fold_convert (type, low); | |
| 1956 high = low; | |
| 1957 } | |
| 1958 else | |
| 1959 { | |
| 1960 /* If the entire case range is unreachable, ignore it. */ | |
| 1961 if ((TREE_CODE (min_value) == INTEGER_CST | |
| 1962 && tree_int_cst_compare (high, min_value) < 0) | |
| 1963 || (TREE_CODE (max_value) == INTEGER_CST | |
| 1964 && tree_int_cst_compare (low, max_value) > 0)) | |
| 1965 return head; | |
| 1966 | |
| 1967 /* If the lower bound is less than the index type's minimum | |
| 1968 value, truncate the range bounds. */ | |
| 1969 if (TREE_CODE (min_value) == INTEGER_CST | |
| 1970 && tree_int_cst_compare (low, min_value) < 0) | |
| 1971 low = min_value; | |
| 1972 low = fold_convert (type, low); | |
| 1973 | |
| 1974 /* If the upper bound is greater than the index type's maximum | |
| 1975 value, truncate the range bounds. */ | |
| 1976 if (TREE_CODE (max_value) == INTEGER_CST | |
| 1977 && tree_int_cst_compare (high, max_value) > 0) | |
| 1978 high = max_value; | |
| 1979 high = fold_convert (type, high); | |
| 1980 } | |
| 1981 | |
| 1982 | |
| 1983 /* Add this label to the chain. Make sure to drop overflow flags. */ | |
| 1984 r = (struct case_node *) pool_alloc (case_node_pool); | |
| 1985 r->low = build_int_cst_wide (TREE_TYPE (low), TREE_INT_CST_LOW (low), | |
| 1986 TREE_INT_CST_HIGH (low)); | |
| 1987 r->high = build_int_cst_wide (TREE_TYPE (high), TREE_INT_CST_LOW (high), | |
| 1988 TREE_INT_CST_HIGH (high)); | |
| 1989 r->code_label = label; | |
| 1990 r->parent = r->left = NULL; | |
| 1991 r->right = head; | |
| 1992 return r; | |
| 1993 } | |
| 1994 | |
| 1995 /* Maximum number of case bit tests. */ | |
| 1996 #define MAX_CASE_BIT_TESTS 3 | |
| 1997 | |
| 1998 /* By default, enable case bit tests on targets with ashlsi3. */ | |
| 1999 #ifndef CASE_USE_BIT_TESTS | |
| 2000 #define CASE_USE_BIT_TESTS (optab_handler (ashl_optab, word_mode)->insn_code \ | |
| 2001 != CODE_FOR_nothing) | |
| 2002 #endif | |
| 2003 | |
| 2004 | |
| 2005 /* A case_bit_test represents a set of case nodes that may be | |
| 2006 selected from using a bit-wise comparison. HI and LO hold | |
| 2007 the integer to be tested against, LABEL contains the label | |
| 2008 to jump to upon success and BITS counts the number of case | |
| 2009 nodes handled by this test, typically the number of bits | |
| 2010 set in HI:LO. */ | |
| 2011 | |
| 2012 struct case_bit_test | |
| 2013 { | |
| 2014 HOST_WIDE_INT hi; | |
| 2015 HOST_WIDE_INT lo; | |
| 2016 rtx label; | |
| 2017 int bits; | |
| 2018 }; | |
| 2019 | |
| 2020 /* Determine whether "1 << x" is relatively cheap in word_mode. */ | |
| 2021 | |
| 2022 static | |
| 2023 bool lshift_cheap_p (void) | |
| 2024 { | |
| 2025 static bool init = false; | |
| 2026 static bool cheap = true; | |
| 2027 | |
| 2028 if (!init) | |
| 2029 { | |
| 2030 rtx reg = gen_rtx_REG (word_mode, 10000); | |
| 2031 int cost = rtx_cost (gen_rtx_ASHIFT (word_mode, const1_rtx, reg), SET, | |
| 2032 optimize_insn_for_speed_p ()); | |
| 2033 cheap = cost < COSTS_N_INSNS (3); | |
| 2034 init = true; | |
| 2035 } | |
| 2036 | |
| 2037 return cheap; | |
| 2038 } | |
| 2039 | |
| 2040 /* Comparison function for qsort to order bit tests by decreasing | |
| 2041 number of case nodes, i.e. the node with the most cases gets | |
| 2042 tested first. */ | |
| 2043 | |
| 2044 static int | |
| 2045 case_bit_test_cmp (const void *p1, const void *p2) | |
| 2046 { | |
| 2047 const struct case_bit_test *const d1 = (const struct case_bit_test *) p1; | |
| 2048 const struct case_bit_test *const d2 = (const struct case_bit_test *) p2; | |
| 2049 | |
| 2050 if (d2->bits != d1->bits) | |
| 2051 return d2->bits - d1->bits; | |
| 2052 | |
| 2053 /* Stabilize the sort. */ | |
| 2054 return CODE_LABEL_NUMBER (d2->label) - CODE_LABEL_NUMBER (d1->label); | |
| 2055 } | |
| 2056 | |
| 2057 /* Expand a switch statement by a short sequence of bit-wise | |
| 2058 comparisons. "switch(x)" is effectively converted into | |
| 2059 "if ((1 << (x-MINVAL)) & CST)" where CST and MINVAL are | |
| 2060 integer constants. | |
| 2061 | |
| 2062 INDEX_EXPR is the value being switched on, which is of | |
| 2063 type INDEX_TYPE. MINVAL is the lowest case value of in | |
| 2064 the case nodes, of INDEX_TYPE type, and RANGE is highest | |
| 2065 value minus MINVAL, also of type INDEX_TYPE. NODES is | |
| 2066 the set of case nodes, and DEFAULT_LABEL is the label to | |
| 2067 branch to should none of the cases match. | |
| 2068 | |
| 2069 There *MUST* be MAX_CASE_BIT_TESTS or less unique case | |
| 2070 node targets. */ | |
| 2071 | |
| 2072 static void | |
| 2073 emit_case_bit_tests (tree index_type, tree index_expr, tree minval, | |
| 2074 tree range, case_node_ptr nodes, rtx default_label) | |
| 2075 { | |
| 2076 struct case_bit_test test[MAX_CASE_BIT_TESTS]; | |
| 2077 enum machine_mode mode; | |
| 2078 rtx expr, index, label; | |
| 2079 unsigned int i,j,lo,hi; | |
| 2080 struct case_node *n; | |
| 2081 unsigned int count; | |
| 2082 | |
| 2083 count = 0; | |
| 2084 for (n = nodes; n; n = n->right) | |
| 2085 { | |
| 2086 label = label_rtx (n->code_label); | |
| 2087 for (i = 0; i < count; i++) | |
| 2088 if (label == test[i].label) | |
| 2089 break; | |
| 2090 | |
| 2091 if (i == count) | |
| 2092 { | |
| 2093 gcc_assert (count < MAX_CASE_BIT_TESTS); | |
| 2094 test[i].hi = 0; | |
| 2095 test[i].lo = 0; | |
| 2096 test[i].label = label; | |
| 2097 test[i].bits = 1; | |
| 2098 count++; | |
| 2099 } | |
| 2100 else | |
| 2101 test[i].bits++; | |
| 2102 | |
| 2103 lo = tree_low_cst (fold_build2 (MINUS_EXPR, index_type, | |
| 2104 n->low, minval), 1); | |
| 2105 hi = tree_low_cst (fold_build2 (MINUS_EXPR, index_type, | |
| 2106 n->high, minval), 1); | |
| 2107 for (j = lo; j <= hi; j++) | |
| 2108 if (j >= HOST_BITS_PER_WIDE_INT) | |
| 2109 test[i].hi |= (HOST_WIDE_INT) 1 << (j - HOST_BITS_PER_INT); | |
| 2110 else | |
| 2111 test[i].lo |= (HOST_WIDE_INT) 1 << j; | |
| 2112 } | |
| 2113 | |
| 2114 qsort (test, count, sizeof(*test), case_bit_test_cmp); | |
| 2115 | |
| 2116 index_expr = fold_build2 (MINUS_EXPR, index_type, | |
| 2117 fold_convert (index_type, index_expr), | |
| 2118 fold_convert (index_type, minval)); | |
| 2119 index = expand_normal (index_expr); | |
| 2120 do_pending_stack_adjust (); | |
| 2121 | |
| 2122 mode = TYPE_MODE (index_type); | |
| 2123 expr = expand_normal (range); | |
| 2124 if (default_label) | |
| 2125 emit_cmp_and_jump_insns (index, expr, GTU, NULL_RTX, mode, 1, | |
| 2126 default_label); | |
| 2127 | |
| 2128 index = convert_to_mode (word_mode, index, 0); | |
| 2129 index = expand_binop (word_mode, ashl_optab, const1_rtx, | |
| 2130 index, NULL_RTX, 1, OPTAB_WIDEN); | |
| 2131 | |
| 2132 for (i = 0; i < count; i++) | |
| 2133 { | |
| 2134 expr = immed_double_const (test[i].lo, test[i].hi, word_mode); | |
| 2135 expr = expand_binop (word_mode, and_optab, index, expr, | |
| 2136 NULL_RTX, 1, OPTAB_WIDEN); | |
| 2137 emit_cmp_and_jump_insns (expr, const0_rtx, NE, NULL_RTX, | |
| 2138 word_mode, 1, test[i].label); | |
| 2139 } | |
| 2140 | |
| 2141 if (default_label) | |
| 2142 emit_jump (default_label); | |
| 2143 } | |
| 2144 | |
| 2145 #ifndef HAVE_casesi | |
| 2146 #define HAVE_casesi 0 | |
| 2147 #endif | |
| 2148 | |
| 2149 #ifndef HAVE_tablejump | |
| 2150 #define HAVE_tablejump 0 | |
| 2151 #endif | |
| 2152 | |
| 2153 /* Terminate a case (Pascal/Ada) or switch (C) statement | |
| 2154 in which ORIG_INDEX is the expression to be tested. | |
| 2155 If ORIG_TYPE is not NULL, it is the original ORIG_INDEX | |
| 2156 type as given in the source before any compiler conversions. | |
| 2157 Generate the code to test it and jump to the right place. */ | |
| 2158 | |
| 2159 void | |
| 2160 expand_case (tree exp) | |
| 2161 { | |
| 2162 tree minval = NULL_TREE, maxval = NULL_TREE, range = NULL_TREE; | |
| 2163 rtx default_label = 0; | |
| 2164 struct case_node *n; | |
| 2165 unsigned int count, uniq; | |
| 2166 rtx index; | |
| 2167 rtx table_label; | |
| 2168 int ncases; | |
| 2169 rtx *labelvec; | |
| 2170 int i; | |
| 2171 rtx before_case, end, lab; | |
| 2172 | |
| 2173 tree vec = SWITCH_LABELS (exp); | |
| 2174 tree orig_type = TREE_TYPE (exp); | |
| 2175 tree index_expr = SWITCH_COND (exp); | |
| 2176 tree index_type = TREE_TYPE (index_expr); | |
| 2177 int unsignedp = TYPE_UNSIGNED (index_type); | |
| 2178 | |
| 2179 /* The insn after which the case dispatch should finally | |
| 2180 be emitted. Zero for a dummy. */ | |
| 2181 rtx start; | |
| 2182 | |
| 2183 /* A list of case labels; it is first built as a list and it may then | |
| 2184 be rearranged into a nearly balanced binary tree. */ | |
| 2185 struct case_node *case_list = 0; | |
| 2186 | |
| 2187 /* Label to jump to if no case matches. */ | |
| 2188 tree default_label_decl = NULL_TREE; | |
| 2189 | |
| 2190 alloc_pool case_node_pool = create_alloc_pool ("struct case_node pool", | |
| 2191 sizeof (struct case_node), | |
| 2192 100); | |
| 2193 | |
| 2194 /* The switch body is lowered in gimplify.c, we should never have | |
| 2195 switches with a non-NULL SWITCH_BODY here. */ | |
| 2196 gcc_assert (!SWITCH_BODY (exp)); | |
| 2197 gcc_assert (SWITCH_LABELS (exp)); | |
| 2198 | |
| 2199 do_pending_stack_adjust (); | |
| 2200 | |
| 2201 /* An ERROR_MARK occurs for various reasons including invalid data type. */ | |
| 2202 if (index_type != error_mark_node) | |
| 2203 { | |
| 2204 tree elt; | |
| 2205 bitmap label_bitmap; | |
| 2206 int vl = TREE_VEC_LENGTH (vec); | |
| 2207 | |
| 2208 /* cleanup_tree_cfg removes all SWITCH_EXPR with their index | |
| 2209 expressions being INTEGER_CST. */ | |
| 2210 gcc_assert (TREE_CODE (index_expr) != INTEGER_CST); | |
| 2211 | |
| 2212 /* The default case, if ever taken, is at the end of TREE_VEC. */ | |
| 2213 elt = TREE_VEC_ELT (vec, vl - 1); | |
| 2214 if (!CASE_LOW (elt) && !CASE_HIGH (elt)) | |
| 2215 { | |
| 2216 default_label_decl = CASE_LABEL (elt); | |
| 2217 --vl; | |
| 2218 } | |
| 2219 | |
| 2220 for (i = vl - 1; i >= 0; --i) | |
| 2221 { | |
| 2222 tree low, high; | |
| 2223 elt = TREE_VEC_ELT (vec, i); | |
| 2224 | |
| 2225 low = CASE_LOW (elt); | |
| 2226 gcc_assert (low); | |
| 2227 high = CASE_HIGH (elt); | |
| 2228 | |
| 2229 /* Discard empty ranges. */ | |
| 2230 if (high && tree_int_cst_lt (high, low)) | |
| 2231 continue; | |
| 2232 | |
| 2233 case_list = add_case_node (case_list, index_type, low, high, | |
| 2234 CASE_LABEL (elt), case_node_pool); | |
| 2235 } | |
| 2236 | |
| 2237 | |
| 2238 before_case = start = get_last_insn (); | |
| 2239 if (default_label_decl) | |
| 2240 default_label = label_rtx (default_label_decl); | |
| 2241 | |
| 2242 /* Get upper and lower bounds of case values. */ | |
| 2243 | |
| 2244 uniq = 0; | |
| 2245 count = 0; | |
| 2246 label_bitmap = BITMAP_ALLOC (NULL); | |
| 2247 for (n = case_list; n; n = n->right) | |
| 2248 { | |
| 2249 /* Count the elements and track the largest and smallest | |
| 2250 of them (treating them as signed even if they are not). */ | |
| 2251 if (count++ == 0) | |
| 2252 { | |
| 2253 minval = n->low; | |
| 2254 maxval = n->high; | |
| 2255 } | |
| 2256 else | |
| 2257 { | |
| 2258 if (tree_int_cst_lt (n->low, minval)) | |
| 2259 minval = n->low; | |
| 2260 if (tree_int_cst_lt (maxval, n->high)) | |
| 2261 maxval = n->high; | |
| 2262 } | |
| 2263 /* A range counts double, since it requires two compares. */ | |
| 2264 if (! tree_int_cst_equal (n->low, n->high)) | |
| 2265 count++; | |
| 2266 | |
| 2267 /* If we have not seen this label yet, then increase the | |
| 2268 number of unique case node targets seen. */ | |
| 2269 lab = label_rtx (n->code_label); | |
| 2270 if (!bitmap_bit_p (label_bitmap, CODE_LABEL_NUMBER (lab))) | |
| 2271 { | |
| 2272 bitmap_set_bit (label_bitmap, CODE_LABEL_NUMBER (lab)); | |
| 2273 uniq++; | |
| 2274 } | |
| 2275 } | |
| 2276 | |
| 2277 BITMAP_FREE (label_bitmap); | |
| 2278 | |
| 2279 /* cleanup_tree_cfg removes all SWITCH_EXPR with a single | |
| 2280 destination, such as one with a default case only. However, | |
| 2281 it doesn't remove cases that are out of range for the switch | |
| 2282 type, so we may still get a zero here. */ | |
| 2283 if (count == 0) | |
| 2284 { | |
| 2285 if (default_label) | |
| 2286 emit_jump (default_label); | |
| 2287 free_alloc_pool (case_node_pool); | |
| 2288 return; | |
| 2289 } | |
| 2290 | |
| 2291 /* Compute span of values. */ | |
| 2292 range = fold_build2 (MINUS_EXPR, index_type, maxval, minval); | |
| 2293 | |
| 2294 /* Try implementing this switch statement by a short sequence of | |
| 2295 bit-wise comparisons. However, we let the binary-tree case | |
| 2296 below handle constant index expressions. */ | |
| 2297 if (CASE_USE_BIT_TESTS | |
| 2298 && ! TREE_CONSTANT (index_expr) | |
| 2299 && compare_tree_int (range, GET_MODE_BITSIZE (word_mode)) < 0 | |
| 2300 && compare_tree_int (range, 0) > 0 | |
| 2301 && lshift_cheap_p () | |
| 2302 && ((uniq == 1 && count >= 3) | |
| 2303 || (uniq == 2 && count >= 5) | |
| 2304 || (uniq == 3 && count >= 6))) | |
| 2305 { | |
| 2306 /* Optimize the case where all the case values fit in a | |
| 2307 word without having to subtract MINVAL. In this case, | |
| 2308 we can optimize away the subtraction. */ | |
| 2309 if (compare_tree_int (minval, 0) > 0 | |
| 2310 && compare_tree_int (maxval, GET_MODE_BITSIZE (word_mode)) < 0) | |
| 2311 { | |
| 2312 minval = build_int_cst (index_type, 0); | |
| 2313 range = maxval; | |
| 2314 } | |
| 2315 emit_case_bit_tests (index_type, index_expr, minval, range, | |
| 2316 case_list, default_label); | |
| 2317 } | |
| 2318 | |
| 2319 /* If range of values is much bigger than number of values, | |
| 2320 make a sequence of conditional branches instead of a dispatch. | |
| 2321 If the switch-index is a constant, do it this way | |
| 2322 because we can optimize it. */ | |
| 2323 | |
| 2324 else if (count < case_values_threshold () | |
| 2325 || compare_tree_int (range, | |
| 2326 (optimize_insn_for_size_p () ? 3 : 10) * count) > 0 | |
| 2327 /* RANGE may be signed, and really large ranges will show up | |
| 2328 as negative numbers. */ | |
| 2329 || compare_tree_int (range, 0) < 0 | |
| 2330 #ifndef ASM_OUTPUT_ADDR_DIFF_ELT | |
| 2331 || flag_pic | |
| 2332 #endif | |
| 2333 || !flag_jump_tables | |
| 2334 || TREE_CONSTANT (index_expr) | |
| 2335 /* If neither casesi or tablejump is available, we can | |
| 2336 only go this way. */ | |
| 2337 || (!HAVE_casesi && !HAVE_tablejump)) | |
| 2338 { | |
| 2339 index = expand_normal (index_expr); | |
| 2340 | |
| 2341 /* If the index is a short or char that we do not have | |
| 2342 an insn to handle comparisons directly, convert it to | |
| 2343 a full integer now, rather than letting each comparison | |
| 2344 generate the conversion. */ | |
| 2345 | |
| 2346 if (GET_MODE_CLASS (GET_MODE (index)) == MODE_INT | |
| 2347 && ! have_insn_for (COMPARE, GET_MODE (index))) | |
| 2348 { | |
| 2349 enum machine_mode wider_mode; | |
| 2350 for (wider_mode = GET_MODE (index); wider_mode != VOIDmode; | |
| 2351 wider_mode = GET_MODE_WIDER_MODE (wider_mode)) | |
| 2352 if (have_insn_for (COMPARE, wider_mode)) | |
| 2353 { | |
| 2354 index = convert_to_mode (wider_mode, index, unsignedp); | |
| 2355 break; | |
| 2356 } | |
| 2357 } | |
| 2358 | |
| 2359 do_pending_stack_adjust (); | |
| 2360 | |
| 2361 if (MEM_P (index)) | |
| 2362 index = copy_to_reg (index); | |
| 2363 | |
| 2364 /* We generate a binary decision tree to select the | |
| 2365 appropriate target code. This is done as follows: | |
| 2366 | |
| 2367 The list of cases is rearranged into a binary tree, | |
| 2368 nearly optimal assuming equal probability for each case. | |
| 2369 | |
| 2370 The tree is transformed into RTL, eliminating | |
| 2371 redundant test conditions at the same time. | |
| 2372 | |
| 2373 If program flow could reach the end of the | |
| 2374 decision tree an unconditional jump to the | |
| 2375 default code is emitted. */ | |
| 2376 | |
| 2377 use_cost_table | |
| 2378 = (TREE_CODE (orig_type) != ENUMERAL_TYPE | |
| 2379 && estimate_case_costs (case_list)); | |
| 2380 balance_case_nodes (&case_list, NULL); | |
| 2381 emit_case_nodes (index, case_list, default_label, index_type); | |
| 2382 if (default_label) | |
| 2383 emit_jump (default_label); | |
| 2384 } | |
| 2385 else | |
| 2386 { | |
| 2387 rtx fallback_label = label_rtx (case_list->code_label); | |
| 2388 table_label = gen_label_rtx (); | |
| 2389 if (! try_casesi (index_type, index_expr, minval, range, | |
| 2390 table_label, default_label, fallback_label)) | |
| 2391 { | |
| 2392 bool ok; | |
| 2393 | |
| 2394 /* Index jumptables from zero for suitable values of | |
| 2395 minval to avoid a subtraction. */ | |
| 2396 if (optimize_insn_for_speed_p () | |
| 2397 && compare_tree_int (minval, 0) > 0 | |
| 2398 && compare_tree_int (minval, 3) < 0) | |
| 2399 { | |
| 2400 minval = build_int_cst (index_type, 0); | |
| 2401 range = maxval; | |
| 2402 } | |
| 2403 | |
| 2404 ok = try_tablejump (index_type, index_expr, minval, range, | |
| 2405 table_label, default_label); | |
| 2406 gcc_assert (ok); | |
| 2407 } | |
| 2408 | |
| 2409 /* Get table of labels to jump to, in order of case index. */ | |
| 2410 | |
| 2411 ncases = tree_low_cst (range, 0) + 1; | |
| 2412 labelvec = XALLOCAVEC (rtx, ncases); | |
| 2413 memset (labelvec, 0, ncases * sizeof (rtx)); | |
| 2414 | |
| 2415 for (n = case_list; n; n = n->right) | |
| 2416 { | |
| 2417 /* Compute the low and high bounds relative to the minimum | |
| 2418 value since that should fit in a HOST_WIDE_INT while the | |
| 2419 actual values may not. */ | |
| 2420 HOST_WIDE_INT i_low | |
| 2421 = tree_low_cst (fold_build2 (MINUS_EXPR, index_type, | |
| 2422 n->low, minval), 1); | |
| 2423 HOST_WIDE_INT i_high | |
| 2424 = tree_low_cst (fold_build2 (MINUS_EXPR, index_type, | |
| 2425 n->high, minval), 1); | |
| 2426 HOST_WIDE_INT i; | |
| 2427 | |
| 2428 for (i = i_low; i <= i_high; i ++) | |
| 2429 labelvec[i] | |
| 2430 = gen_rtx_LABEL_REF (Pmode, label_rtx (n->code_label)); | |
| 2431 } | |
| 2432 | |
| 2433 /* Fill in the gaps with the default. We may have gaps at | |
| 2434 the beginning if we tried to avoid the minval subtraction, | |
| 2435 so substitute some label even if the default label was | |
| 2436 deemed unreachable. */ | |
| 2437 if (!default_label) | |
| 2438 default_label = fallback_label; | |
| 2439 for (i = 0; i < ncases; i++) | |
| 2440 if (labelvec[i] == 0) | |
| 2441 labelvec[i] = gen_rtx_LABEL_REF (Pmode, default_label); | |
| 2442 | |
| 2443 /* Output the table. */ | |
| 2444 emit_label (table_label); | |
| 2445 | |
| 2446 if (CASE_VECTOR_PC_RELATIVE || flag_pic) | |
| 2447 emit_jump_insn (gen_rtx_ADDR_DIFF_VEC (CASE_VECTOR_MODE, | |
| 2448 gen_rtx_LABEL_REF (Pmode, table_label), | |
| 2449 gen_rtvec_v (ncases, labelvec), | |
| 2450 const0_rtx, const0_rtx)); | |
| 2451 else | |
| 2452 emit_jump_insn (gen_rtx_ADDR_VEC (CASE_VECTOR_MODE, | |
| 2453 gen_rtvec_v (ncases, labelvec))); | |
| 2454 | |
| 2455 /* Record no drop-through after the table. */ | |
| 2456 emit_barrier (); | |
| 2457 } | |
| 2458 | |
| 2459 before_case = NEXT_INSN (before_case); | |
| 2460 end = get_last_insn (); | |
| 2461 reorder_insns (before_case, end, start); | |
| 2462 } | |
| 2463 | |
| 2464 free_temp_slots (); | |
| 2465 free_alloc_pool (case_node_pool); | |
| 2466 } | |
| 2467 | |
| 2468 /* Generate code to jump to LABEL if OP0 and OP1 are equal in mode MODE. */ | |
| 2469 | |
| 2470 static void | |
| 2471 do_jump_if_equal (enum machine_mode mode, rtx op0, rtx op1, rtx label, | |
| 2472 int unsignedp) | |
| 2473 { | |
| 2474 do_compare_rtx_and_jump (op0, op1, EQ, unsignedp, mode, | |
| 2475 NULL_RTX, NULL_RTX, label); | |
| 2476 } | |
| 2477 | |
| 2478 /* Not all case values are encountered equally. This function | |
| 2479 uses a heuristic to weight case labels, in cases where that | |
| 2480 looks like a reasonable thing to do. | |
| 2481 | |
| 2482 Right now, all we try to guess is text, and we establish the | |
| 2483 following weights: | |
| 2484 | |
| 2485 chars above space: 16 | |
| 2486 digits: 16 | |
| 2487 default: 12 | |
| 2488 space, punct: 8 | |
| 2489 tab: 4 | |
| 2490 newline: 2 | |
| 2491 other "\" chars: 1 | |
| 2492 remaining chars: 0 | |
| 2493 | |
| 2494 If we find any cases in the switch that are not either -1 or in the range | |
| 2495 of valid ASCII characters, or are control characters other than those | |
| 2496 commonly used with "\", don't treat this switch scanning text. | |
| 2497 | |
| 2498 Return 1 if these nodes are suitable for cost estimation, otherwise | |
| 2499 return 0. */ | |
| 2500 | |
| 2501 static int | |
| 2502 estimate_case_costs (case_node_ptr node) | |
| 2503 { | |
| 2504 tree min_ascii = integer_minus_one_node; | |
| 2505 tree max_ascii = build_int_cst (TREE_TYPE (node->high), 127); | |
| 2506 case_node_ptr n; | |
| 2507 int i; | |
| 2508 | |
| 2509 /* If we haven't already made the cost table, make it now. Note that the | |
| 2510 lower bound of the table is -1, not zero. */ | |
| 2511 | |
| 2512 if (! cost_table_initialized) | |
| 2513 { | |
| 2514 cost_table_initialized = 1; | |
| 2515 | |
| 2516 for (i = 0; i < 128; i++) | |
| 2517 { | |
| 2518 if (ISALNUM (i)) | |
| 2519 COST_TABLE (i) = 16; | |
| 2520 else if (ISPUNCT (i)) | |
| 2521 COST_TABLE (i) = 8; | |
| 2522 else if (ISCNTRL (i)) | |
| 2523 COST_TABLE (i) = -1; | |
| 2524 } | |
| 2525 | |
| 2526 COST_TABLE (' ') = 8; | |
| 2527 COST_TABLE ('\t') = 4; | |
| 2528 COST_TABLE ('\0') = 4; | |
| 2529 COST_TABLE ('\n') = 2; | |
| 2530 COST_TABLE ('\f') = 1; | |
| 2531 COST_TABLE ('\v') = 1; | |
| 2532 COST_TABLE ('\b') = 1; | |
| 2533 } | |
| 2534 | |
| 2535 /* See if all the case expressions look like text. It is text if the | |
| 2536 constant is >= -1 and the highest constant is <= 127. Do all comparisons | |
| 2537 as signed arithmetic since we don't want to ever access cost_table with a | |
| 2538 value less than -1. Also check that none of the constants in a range | |
| 2539 are strange control characters. */ | |
| 2540 | |
| 2541 for (n = node; n; n = n->right) | |
| 2542 { | |
| 2543 if (tree_int_cst_lt (n->low, min_ascii) | |
| 2544 || tree_int_cst_lt (max_ascii, n->high)) | |
| 2545 return 0; | |
| 2546 | |
| 2547 for (i = (HOST_WIDE_INT) TREE_INT_CST_LOW (n->low); | |
| 2548 i <= (HOST_WIDE_INT) TREE_INT_CST_LOW (n->high); i++) | |
| 2549 if (COST_TABLE (i) < 0) | |
| 2550 return 0; | |
| 2551 } | |
| 2552 | |
| 2553 /* All interesting values are within the range of interesting | |
| 2554 ASCII characters. */ | |
| 2555 return 1; | |
| 2556 } | |
| 2557 | |
| 2558 /* Take an ordered list of case nodes | |
| 2559 and transform them into a near optimal binary tree, | |
| 2560 on the assumption that any target code selection value is as | |
| 2561 likely as any other. | |
| 2562 | |
| 2563 The transformation is performed by splitting the ordered | |
| 2564 list into two equal sections plus a pivot. The parts are | |
| 2565 then attached to the pivot as left and right branches. Each | |
| 2566 branch is then transformed recursively. */ | |
| 2567 | |
| 2568 static void | |
| 2569 balance_case_nodes (case_node_ptr *head, case_node_ptr parent) | |
| 2570 { | |
| 2571 case_node_ptr np; | |
| 2572 | |
| 2573 np = *head; | |
| 2574 if (np) | |
| 2575 { | |
| 2576 int cost = 0; | |
| 2577 int i = 0; | |
| 2578 int ranges = 0; | |
| 2579 case_node_ptr *npp; | |
| 2580 case_node_ptr left; | |
| 2581 | |
| 2582 /* Count the number of entries on branch. Also count the ranges. */ | |
| 2583 | |
| 2584 while (np) | |
| 2585 { | |
| 2586 if (!tree_int_cst_equal (np->low, np->high)) | |
| 2587 { | |
| 2588 ranges++; | |
| 2589 if (use_cost_table) | |
| 2590 cost += COST_TABLE (TREE_INT_CST_LOW (np->high)); | |
| 2591 } | |
| 2592 | |
| 2593 if (use_cost_table) | |
| 2594 cost += COST_TABLE (TREE_INT_CST_LOW (np->low)); | |
| 2595 | |
| 2596 i++; | |
| 2597 np = np->right; | |
| 2598 } | |
| 2599 | |
| 2600 if (i > 2) | |
| 2601 { | |
| 2602 /* Split this list if it is long enough for that to help. */ | |
| 2603 npp = head; | |
| 2604 left = *npp; | |
| 2605 if (use_cost_table) | |
| 2606 { | |
| 2607 /* Find the place in the list that bisects the list's total cost, | |
| 2608 Here I gets half the total cost. */ | |
| 2609 int n_moved = 0; | |
| 2610 i = (cost + 1) / 2; | |
| 2611 while (1) | |
| 2612 { | |
| 2613 /* Skip nodes while their cost does not reach that amount. */ | |
| 2614 if (!tree_int_cst_equal ((*npp)->low, (*npp)->high)) | |
| 2615 i -= COST_TABLE (TREE_INT_CST_LOW ((*npp)->high)); | |
| 2616 i -= COST_TABLE (TREE_INT_CST_LOW ((*npp)->low)); | |
| 2617 if (i <= 0) | |
| 2618 break; | |
| 2619 npp = &(*npp)->right; | |
| 2620 n_moved += 1; | |
| 2621 } | |
| 2622 if (n_moved == 0) | |
| 2623 { | |
| 2624 /* Leave this branch lopsided, but optimize left-hand | |
| 2625 side and fill in `parent' fields for right-hand side. */ | |
| 2626 np = *head; | |
| 2627 np->parent = parent; | |
| 2628 balance_case_nodes (&np->left, np); | |
| 2629 for (; np->right; np = np->right) | |
| 2630 np->right->parent = np; | |
| 2631 return; | |
| 2632 } | |
| 2633 } | |
| 2634 /* If there are just three nodes, split at the middle one. */ | |
| 2635 else if (i == 3) | |
| 2636 npp = &(*npp)->right; | |
| 2637 else | |
| 2638 { | |
| 2639 /* Find the place in the list that bisects the list's total cost, | |
| 2640 where ranges count as 2. | |
| 2641 Here I gets half the total cost. */ | |
| 2642 i = (i + ranges + 1) / 2; | |
| 2643 while (1) | |
| 2644 { | |
| 2645 /* Skip nodes while their cost does not reach that amount. */ | |
| 2646 if (!tree_int_cst_equal ((*npp)->low, (*npp)->high)) | |
| 2647 i--; | |
| 2648 i--; | |
| 2649 if (i <= 0) | |
| 2650 break; | |
| 2651 npp = &(*npp)->right; | |
| 2652 } | |
| 2653 } | |
| 2654 *head = np = *npp; | |
| 2655 *npp = 0; | |
| 2656 np->parent = parent; | |
| 2657 np->left = left; | |
| 2658 | |
| 2659 /* Optimize each of the two split parts. */ | |
| 2660 balance_case_nodes (&np->left, np); | |
| 2661 balance_case_nodes (&np->right, np); | |
| 2662 } | |
| 2663 else | |
| 2664 { | |
| 2665 /* Else leave this branch as one level, | |
| 2666 but fill in `parent' fields. */ | |
| 2667 np = *head; | |
| 2668 np->parent = parent; | |
| 2669 for (; np->right; np = np->right) | |
| 2670 np->right->parent = np; | |
| 2671 } | |
| 2672 } | |
| 2673 } | |
| 2674 | |
| 2675 /* Search the parent sections of the case node tree | |
| 2676 to see if a test for the lower bound of NODE would be redundant. | |
| 2677 INDEX_TYPE is the type of the index expression. | |
| 2678 | |
| 2679 The instructions to generate the case decision tree are | |
| 2680 output in the same order as nodes are processed so it is | |
| 2681 known that if a parent node checks the range of the current | |
| 2682 node minus one that the current node is bounded at its lower | |
| 2683 span. Thus the test would be redundant. */ | |
| 2684 | |
| 2685 static int | |
| 2686 node_has_low_bound (case_node_ptr node, tree index_type) | |
| 2687 { | |
| 2688 tree low_minus_one; | |
| 2689 case_node_ptr pnode; | |
| 2690 | |
| 2691 /* If the lower bound of this node is the lowest value in the index type, | |
| 2692 we need not test it. */ | |
| 2693 | |
| 2694 if (tree_int_cst_equal (node->low, TYPE_MIN_VALUE (index_type))) | |
| 2695 return 1; | |
| 2696 | |
| 2697 /* If this node has a left branch, the value at the left must be less | |
| 2698 than that at this node, so it cannot be bounded at the bottom and | |
| 2699 we need not bother testing any further. */ | |
| 2700 | |
| 2701 if (node->left) | |
| 2702 return 0; | |
| 2703 | |
| 2704 low_minus_one = fold_build2 (MINUS_EXPR, TREE_TYPE (node->low), | |
| 2705 node->low, | |
| 2706 build_int_cst (TREE_TYPE (node->low), 1)); | |
| 2707 | |
| 2708 /* If the subtraction above overflowed, we can't verify anything. | |
| 2709 Otherwise, look for a parent that tests our value - 1. */ | |
| 2710 | |
| 2711 if (! tree_int_cst_lt (low_minus_one, node->low)) | |
| 2712 return 0; | |
| 2713 | |
| 2714 for (pnode = node->parent; pnode; pnode = pnode->parent) | |
| 2715 if (tree_int_cst_equal (low_minus_one, pnode->high)) | |
| 2716 return 1; | |
| 2717 | |
| 2718 return 0; | |
| 2719 } | |
| 2720 | |
| 2721 /* Search the parent sections of the case node tree | |
| 2722 to see if a test for the upper bound of NODE would be redundant. | |
| 2723 INDEX_TYPE is the type of the index expression. | |
| 2724 | |
| 2725 The instructions to generate the case decision tree are | |
| 2726 output in the same order as nodes are processed so it is | |
| 2727 known that if a parent node checks the range of the current | |
| 2728 node plus one that the current node is bounded at its upper | |
| 2729 span. Thus the test would be redundant. */ | |
| 2730 | |
| 2731 static int | |
| 2732 node_has_high_bound (case_node_ptr node, tree index_type) | |
| 2733 { | |
| 2734 tree high_plus_one; | |
| 2735 case_node_ptr pnode; | |
| 2736 | |
| 2737 /* If there is no upper bound, obviously no test is needed. */ | |
| 2738 | |
| 2739 if (TYPE_MAX_VALUE (index_type) == NULL) | |
| 2740 return 1; | |
| 2741 | |
| 2742 /* If the upper bound of this node is the highest value in the type | |
| 2743 of the index expression, we need not test against it. */ | |
| 2744 | |
| 2745 if (tree_int_cst_equal (node->high, TYPE_MAX_VALUE (index_type))) | |
| 2746 return 1; | |
| 2747 | |
| 2748 /* If this node has a right branch, the value at the right must be greater | |
| 2749 than that at this node, so it cannot be bounded at the top and | |
| 2750 we need not bother testing any further. */ | |
| 2751 | |
| 2752 if (node->right) | |
| 2753 return 0; | |
| 2754 | |
| 2755 high_plus_one = fold_build2 (PLUS_EXPR, TREE_TYPE (node->high), | |
| 2756 node->high, | |
| 2757 build_int_cst (TREE_TYPE (node->high), 1)); | |
| 2758 | |
| 2759 /* If the addition above overflowed, we can't verify anything. | |
| 2760 Otherwise, look for a parent that tests our value + 1. */ | |
| 2761 | |
| 2762 if (! tree_int_cst_lt (node->high, high_plus_one)) | |
| 2763 return 0; | |
| 2764 | |
| 2765 for (pnode = node->parent; pnode; pnode = pnode->parent) | |
| 2766 if (tree_int_cst_equal (high_plus_one, pnode->low)) | |
| 2767 return 1; | |
| 2768 | |
| 2769 return 0; | |
| 2770 } | |
| 2771 | |
| 2772 /* Search the parent sections of the | |
| 2773 case node tree to see if both tests for the upper and lower | |
| 2774 bounds of NODE would be redundant. */ | |
| 2775 | |
| 2776 static int | |
| 2777 node_is_bounded (case_node_ptr node, tree index_type) | |
| 2778 { | |
| 2779 return (node_has_low_bound (node, index_type) | |
| 2780 && node_has_high_bound (node, index_type)); | |
| 2781 } | |
| 2782 | |
| 2783 /* Emit step-by-step code to select a case for the value of INDEX. | |
| 2784 The thus generated decision tree follows the form of the | |
| 2785 case-node binary tree NODE, whose nodes represent test conditions. | |
| 2786 INDEX_TYPE is the type of the index of the switch. | |
| 2787 | |
| 2788 Care is taken to prune redundant tests from the decision tree | |
| 2789 by detecting any boundary conditions already checked by | |
| 2790 emitted rtx. (See node_has_high_bound, node_has_low_bound | |
| 2791 and node_is_bounded, above.) | |
| 2792 | |
| 2793 Where the test conditions can be shown to be redundant we emit | |
| 2794 an unconditional jump to the target code. As a further | |
| 2795 optimization, the subordinates of a tree node are examined to | |
| 2796 check for bounded nodes. In this case conditional and/or | |
| 2797 unconditional jumps as a result of the boundary check for the | |
| 2798 current node are arranged to target the subordinates associated | |
| 2799 code for out of bound conditions on the current node. | |
| 2800 | |
| 2801 We can assume that when control reaches the code generated here, | |
| 2802 the index value has already been compared with the parents | |
| 2803 of this node, and determined to be on the same side of each parent | |
| 2804 as this node is. Thus, if this node tests for the value 51, | |
| 2805 and a parent tested for 52, we don't need to consider | |
| 2806 the possibility of a value greater than 51. If another parent | |
| 2807 tests for the value 50, then this node need not test anything. */ | |
| 2808 | |
| 2809 static void | |
| 2810 emit_case_nodes (rtx index, case_node_ptr node, rtx default_label, | |
| 2811 tree index_type) | |
| 2812 { | |
| 2813 /* If INDEX has an unsigned type, we must make unsigned branches. */ | |
| 2814 int unsignedp = TYPE_UNSIGNED (index_type); | |
| 2815 enum machine_mode mode = GET_MODE (index); | |
| 2816 enum machine_mode imode = TYPE_MODE (index_type); | |
| 2817 | |
| 2818 /* Handle indices detected as constant during RTL expansion. */ | |
| 2819 if (mode == VOIDmode) | |
| 2820 mode = imode; | |
| 2821 | |
| 2822 /* See if our parents have already tested everything for us. | |
| 2823 If they have, emit an unconditional jump for this node. */ | |
| 2824 if (node_is_bounded (node, index_type)) | |
| 2825 emit_jump (label_rtx (node->code_label)); | |
| 2826 | |
| 2827 else if (tree_int_cst_equal (node->low, node->high)) | |
| 2828 { | |
| 2829 /* Node is single valued. First see if the index expression matches | |
| 2830 this node and then check our children, if any. */ | |
| 2831 | |
| 2832 do_jump_if_equal (mode, index, | |
| 2833 convert_modes (mode, imode, | |
| 2834 expand_normal (node->low), | |
| 2835 unsignedp), | |
| 2836 label_rtx (node->code_label), unsignedp); | |
| 2837 | |
| 2838 if (node->right != 0 && node->left != 0) | |
| 2839 { | |
| 2840 /* This node has children on both sides. | |
| 2841 Dispatch to one side or the other | |
| 2842 by comparing the index value with this node's value. | |
| 2843 If one subtree is bounded, check that one first, | |
| 2844 so we can avoid real branches in the tree. */ | |
| 2845 | |
| 2846 if (node_is_bounded (node->right, index_type)) | |
| 2847 { | |
| 2848 emit_cmp_and_jump_insns (index, | |
| 2849 convert_modes | |
| 2850 (mode, imode, | |
| 2851 expand_normal (node->high), | |
| 2852 unsignedp), | |
| 2853 GT, NULL_RTX, mode, unsignedp, | |
| 2854 label_rtx (node->right->code_label)); | |
| 2855 emit_case_nodes (index, node->left, default_label, index_type); | |
| 2856 } | |
| 2857 | |
| 2858 else if (node_is_bounded (node->left, index_type)) | |
| 2859 { | |
| 2860 emit_cmp_and_jump_insns (index, | |
| 2861 convert_modes | |
| 2862 (mode, imode, | |
| 2863 expand_normal (node->high), | |
| 2864 unsignedp), | |
| 2865 LT, NULL_RTX, mode, unsignedp, | |
| 2866 label_rtx (node->left->code_label)); | |
| 2867 emit_case_nodes (index, node->right, default_label, index_type); | |
| 2868 } | |
| 2869 | |
| 2870 /* If both children are single-valued cases with no | |
| 2871 children, finish up all the work. This way, we can save | |
| 2872 one ordered comparison. */ | |
| 2873 else if (tree_int_cst_equal (node->right->low, node->right->high) | |
| 2874 && node->right->left == 0 | |
| 2875 && node->right->right == 0 | |
| 2876 && tree_int_cst_equal (node->left->low, node->left->high) | |
| 2877 && node->left->left == 0 | |
| 2878 && node->left->right == 0) | |
| 2879 { | |
| 2880 /* Neither node is bounded. First distinguish the two sides; | |
| 2881 then emit the code for one side at a time. */ | |
| 2882 | |
| 2883 /* See if the value matches what the right hand side | |
| 2884 wants. */ | |
| 2885 do_jump_if_equal (mode, index, | |
| 2886 convert_modes (mode, imode, | |
| 2887 expand_normal (node->right->low), | |
| 2888 unsignedp), | |
| 2889 label_rtx (node->right->code_label), | |
| 2890 unsignedp); | |
| 2891 | |
| 2892 /* See if the value matches what the left hand side | |
| 2893 wants. */ | |
| 2894 do_jump_if_equal (mode, index, | |
| 2895 convert_modes (mode, imode, | |
| 2896 expand_normal (node->left->low), | |
| 2897 unsignedp), | |
| 2898 label_rtx (node->left->code_label), | |
| 2899 unsignedp); | |
| 2900 } | |
| 2901 | |
| 2902 else | |
| 2903 { | |
| 2904 /* Neither node is bounded. First distinguish the two sides; | |
| 2905 then emit the code for one side at a time. */ | |
| 2906 | |
| 2907 tree test_label = build_decl (LABEL_DECL, NULL_TREE, NULL_TREE); | |
| 2908 | |
| 2909 /* See if the value is on the right. */ | |
| 2910 emit_cmp_and_jump_insns (index, | |
| 2911 convert_modes | |
| 2912 (mode, imode, | |
| 2913 expand_normal (node->high), | |
| 2914 unsignedp), | |
| 2915 GT, NULL_RTX, mode, unsignedp, | |
| 2916 label_rtx (test_label)); | |
| 2917 | |
| 2918 /* Value must be on the left. | |
| 2919 Handle the left-hand subtree. */ | |
| 2920 emit_case_nodes (index, node->left, default_label, index_type); | |
| 2921 /* If left-hand subtree does nothing, | |
| 2922 go to default. */ | |
| 2923 if (default_label) | |
| 2924 emit_jump (default_label); | |
| 2925 | |
| 2926 /* Code branches here for the right-hand subtree. */ | |
| 2927 expand_label (test_label); | |
| 2928 emit_case_nodes (index, node->right, default_label, index_type); | |
| 2929 } | |
| 2930 } | |
| 2931 | |
| 2932 else if (node->right != 0 && node->left == 0) | |
| 2933 { | |
| 2934 /* Here we have a right child but no left so we issue a conditional | |
| 2935 branch to default and process the right child. | |
| 2936 | |
| 2937 Omit the conditional branch to default if the right child | |
| 2938 does not have any children and is single valued; it would | |
| 2939 cost too much space to save so little time. */ | |
| 2940 | |
| 2941 if (node->right->right || node->right->left | |
| 2942 || !tree_int_cst_equal (node->right->low, node->right->high)) | |
| 2943 { | |
| 2944 if (!node_has_low_bound (node, index_type)) | |
| 2945 { | |
| 2946 emit_cmp_and_jump_insns (index, | |
| 2947 convert_modes | |
| 2948 (mode, imode, | |
| 2949 expand_normal (node->high), | |
| 2950 unsignedp), | |
| 2951 LT, NULL_RTX, mode, unsignedp, | |
| 2952 default_label); | |
| 2953 } | |
| 2954 | |
| 2955 emit_case_nodes (index, node->right, default_label, index_type); | |
| 2956 } | |
| 2957 else | |
| 2958 /* We cannot process node->right normally | |
| 2959 since we haven't ruled out the numbers less than | |
| 2960 this node's value. So handle node->right explicitly. */ | |
| 2961 do_jump_if_equal (mode, index, | |
| 2962 convert_modes | |
| 2963 (mode, imode, | |
| 2964 expand_normal (node->right->low), | |
| 2965 unsignedp), | |
| 2966 label_rtx (node->right->code_label), unsignedp); | |
| 2967 } | |
| 2968 | |
| 2969 else if (node->right == 0 && node->left != 0) | |
| 2970 { | |
| 2971 /* Just one subtree, on the left. */ | |
| 2972 if (node->left->left || node->left->right | |
| 2973 || !tree_int_cst_equal (node->left->low, node->left->high)) | |
| 2974 { | |
| 2975 if (!node_has_high_bound (node, index_type)) | |
| 2976 { | |
| 2977 emit_cmp_and_jump_insns (index, | |
| 2978 convert_modes | |
| 2979 (mode, imode, | |
| 2980 expand_normal (node->high), | |
| 2981 unsignedp), | |
| 2982 GT, NULL_RTX, mode, unsignedp, | |
| 2983 default_label); | |
| 2984 } | |
| 2985 | |
| 2986 emit_case_nodes (index, node->left, default_label, index_type); | |
| 2987 } | |
| 2988 else | |
| 2989 /* We cannot process node->left normally | |
| 2990 since we haven't ruled out the numbers less than | |
| 2991 this node's value. So handle node->left explicitly. */ | |
| 2992 do_jump_if_equal (mode, index, | |
| 2993 convert_modes | |
| 2994 (mode, imode, | |
| 2995 expand_normal (node->left->low), | |
| 2996 unsignedp), | |
| 2997 label_rtx (node->left->code_label), unsignedp); | |
| 2998 } | |
| 2999 } | |
| 3000 else | |
| 3001 { | |
| 3002 /* Node is a range. These cases are very similar to those for a single | |
| 3003 value, except that we do not start by testing whether this node | |
| 3004 is the one to branch to. */ | |
| 3005 | |
| 3006 if (node->right != 0 && node->left != 0) | |
| 3007 { | |
| 3008 /* Node has subtrees on both sides. | |
| 3009 If the right-hand subtree is bounded, | |
| 3010 test for it first, since we can go straight there. | |
| 3011 Otherwise, we need to make a branch in the control structure, | |
| 3012 then handle the two subtrees. */ | |
| 3013 tree test_label = 0; | |
| 3014 | |
| 3015 if (node_is_bounded (node->right, index_type)) | |
| 3016 /* Right hand node is fully bounded so we can eliminate any | |
| 3017 testing and branch directly to the target code. */ | |
| 3018 emit_cmp_and_jump_insns (index, | |
| 3019 convert_modes | |
| 3020 (mode, imode, | |
| 3021 expand_normal (node->high), | |
| 3022 unsignedp), | |
| 3023 GT, NULL_RTX, mode, unsignedp, | |
| 3024 label_rtx (node->right->code_label)); | |
| 3025 else | |
| 3026 { | |
| 3027 /* Right hand node requires testing. | |
| 3028 Branch to a label where we will handle it later. */ | |
| 3029 | |
| 3030 test_label = build_decl (LABEL_DECL, NULL_TREE, NULL_TREE); | |
| 3031 emit_cmp_and_jump_insns (index, | |
| 3032 convert_modes | |
| 3033 (mode, imode, | |
| 3034 expand_normal (node->high), | |
| 3035 unsignedp), | |
| 3036 GT, NULL_RTX, mode, unsignedp, | |
| 3037 label_rtx (test_label)); | |
| 3038 } | |
| 3039 | |
| 3040 /* Value belongs to this node or to the left-hand subtree. */ | |
| 3041 | |
| 3042 emit_cmp_and_jump_insns (index, | |
| 3043 convert_modes | |
| 3044 (mode, imode, | |
| 3045 expand_normal (node->low), | |
| 3046 unsignedp), | |
| 3047 GE, NULL_RTX, mode, unsignedp, | |
| 3048 label_rtx (node->code_label)); | |
| 3049 | |
| 3050 /* Handle the left-hand subtree. */ | |
| 3051 emit_case_nodes (index, node->left, default_label, index_type); | |
| 3052 | |
| 3053 /* If right node had to be handled later, do that now. */ | |
| 3054 | |
| 3055 if (test_label) | |
| 3056 { | |
| 3057 /* If the left-hand subtree fell through, | |
| 3058 don't let it fall into the right-hand subtree. */ | |
| 3059 if (default_label) | |
| 3060 emit_jump (default_label); | |
| 3061 | |
| 3062 expand_label (test_label); | |
| 3063 emit_case_nodes (index, node->right, default_label, index_type); | |
| 3064 } | |
| 3065 } | |
| 3066 | |
| 3067 else if (node->right != 0 && node->left == 0) | |
| 3068 { | |
| 3069 /* Deal with values to the left of this node, | |
| 3070 if they are possible. */ | |
| 3071 if (!node_has_low_bound (node, index_type)) | |
| 3072 { | |
| 3073 emit_cmp_and_jump_insns (index, | |
| 3074 convert_modes | |
| 3075 (mode, imode, | |
| 3076 expand_normal (node->low), | |
| 3077 unsignedp), | |
| 3078 LT, NULL_RTX, mode, unsignedp, | |
| 3079 default_label); | |
| 3080 } | |
| 3081 | |
| 3082 /* Value belongs to this node or to the right-hand subtree. */ | |
| 3083 | |
| 3084 emit_cmp_and_jump_insns (index, | |
| 3085 convert_modes | |
| 3086 (mode, imode, | |
| 3087 expand_normal (node->high), | |
| 3088 unsignedp), | |
| 3089 LE, NULL_RTX, mode, unsignedp, | |
| 3090 label_rtx (node->code_label)); | |
| 3091 | |
| 3092 emit_case_nodes (index, node->right, default_label, index_type); | |
| 3093 } | |
| 3094 | |
| 3095 else if (node->right == 0 && node->left != 0) | |
| 3096 { | |
| 3097 /* Deal with values to the right of this node, | |
| 3098 if they are possible. */ | |
| 3099 if (!node_has_high_bound (node, index_type)) | |
| 3100 { | |
| 3101 emit_cmp_and_jump_insns (index, | |
| 3102 convert_modes | |
| 3103 (mode, imode, | |
| 3104 expand_normal (node->high), | |
| 3105 unsignedp), | |
| 3106 GT, NULL_RTX, mode, unsignedp, | |
| 3107 default_label); | |
| 3108 } | |
| 3109 | |
| 3110 /* Value belongs to this node or to the left-hand subtree. */ | |
| 3111 | |
| 3112 emit_cmp_and_jump_insns (index, | |
| 3113 convert_modes | |
| 3114 (mode, imode, | |
| 3115 expand_normal (node->low), | |
| 3116 unsignedp), | |
| 3117 GE, NULL_RTX, mode, unsignedp, | |
| 3118 label_rtx (node->code_label)); | |
| 3119 | |
| 3120 emit_case_nodes (index, node->left, default_label, index_type); | |
| 3121 } | |
| 3122 | |
| 3123 else | |
| 3124 { | |
| 3125 /* Node has no children so we check low and high bounds to remove | |
| 3126 redundant tests. Only one of the bounds can exist, | |
| 3127 since otherwise this node is bounded--a case tested already. */ | |
| 3128 int high_bound = node_has_high_bound (node, index_type); | |
| 3129 int low_bound = node_has_low_bound (node, index_type); | |
| 3130 | |
| 3131 if (!high_bound && low_bound) | |
| 3132 { | |
| 3133 emit_cmp_and_jump_insns (index, | |
| 3134 convert_modes | |
| 3135 (mode, imode, | |
| 3136 expand_normal (node->high), | |
| 3137 unsignedp), | |
| 3138 GT, NULL_RTX, mode, unsignedp, | |
| 3139 default_label); | |
| 3140 } | |
| 3141 | |
| 3142 else if (!low_bound && high_bound) | |
| 3143 { | |
| 3144 emit_cmp_and_jump_insns (index, | |
| 3145 convert_modes | |
| 3146 (mode, imode, | |
| 3147 expand_normal (node->low), | |
| 3148 unsignedp), | |
| 3149 LT, NULL_RTX, mode, unsignedp, | |
| 3150 default_label); | |
| 3151 } | |
| 3152 else if (!low_bound && !high_bound) | |
| 3153 { | |
| 3154 /* Widen LOW and HIGH to the same width as INDEX. */ | |
| 3155 tree type = lang_hooks.types.type_for_mode (mode, unsignedp); | |
| 3156 tree low = build1 (CONVERT_EXPR, type, node->low); | |
| 3157 tree high = build1 (CONVERT_EXPR, type, node->high); | |
| 3158 rtx low_rtx, new_index, new_bound; | |
| 3159 | |
| 3160 /* Instead of doing two branches, emit one unsigned branch for | |
| 3161 (index-low) > (high-low). */ | |
| 3162 low_rtx = expand_expr (low, NULL_RTX, mode, EXPAND_NORMAL); | |
| 3163 new_index = expand_simple_binop (mode, MINUS, index, low_rtx, | |
| 3164 NULL_RTX, unsignedp, | |
| 3165 OPTAB_WIDEN); | |
| 3166 new_bound = expand_expr (fold_build2 (MINUS_EXPR, type, | |
| 3167 high, low), | |
| 3168 NULL_RTX, mode, EXPAND_NORMAL); | |
| 3169 | |
| 3170 emit_cmp_and_jump_insns (new_index, new_bound, GT, NULL_RTX, | |
| 3171 mode, 1, default_label); | |
| 3172 } | |
| 3173 | |
| 3174 emit_jump (label_rtx (node->code_label)); | |
| 3175 } | |
| 3176 } | |
| 3177 } |