1 /* 2 * Copyright (c) 1997, 2020, Oracle and/or its affiliates. All rights reserved. 3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. 4 * 5 * This code is free software; you can redistribute it and/or modify it 6 * under the terms of the GNU General Public License version 2 only, as 7 * published by the Free Software Foundation. 8 * 9 * This code is distributed in the hope that it will be useful, but WITHOUT 10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 12 * version 2 for more details (a copy is included in the LICENSE file that 13 * accompanied this code). 14 * 15 * You should have received a copy of the GNU General Public License version 16 * 2 along with this work; if not, write to the Free Software Foundation, 17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. 18 * 19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA 20 * or visit www.oracle.com if you need additional information or have any 21 * questions. 22 * 23 */ 24 25 #include "precompiled.hpp" 26 #include "opto/ad.hpp" 27 #include "opto/chaitin.hpp" 28 #include "opto/compile.hpp" 29 #include "opto/matcher.hpp" 30 #include "opto/node.hpp" 31 #include "opto/regmask.hpp" 32 #include "utilities/population_count.hpp" 33 #include "utilities/powerOfTwo.hpp" 34 35 #define RM_SIZE _RM_SIZE /* a constant private to the class RegMask */ 36 37 //------------------------------dump------------------------------------------- 38 39 #ifndef PRODUCT 40 void OptoReg::dump(int r, outputStream *st) { 41 switch (r) { 42 case Special: st->print("r---"); break; 43 case Bad: st->print("rBAD"); break; 44 default: 45 if (r < _last_Mach_Reg) st->print("%s", Matcher::regName[r]); 46 else st->print("rS%d",r); 47 break; 48 } 49 } 50 #endif 51 52 53 //============================================================================= 54 const RegMask RegMask::Empty( 55 # define BODY(I) 0, 56 FORALL_BODY 57 # undef BODY 58 0 59 ); 60 61 //============================================================================= 62 bool RegMask::is_vector(uint ireg) { 63 return (ireg == Op_VecA || ireg == Op_VecS || ireg == Op_VecD || 64 ireg == Op_VecX || ireg == Op_VecY || ireg == Op_VecZ ); 65 } 66 67 int RegMask::num_registers(uint ireg) { 68 switch(ireg) { 69 case Op_VecZ: 70 return SlotsPerVecZ; 71 case Op_VecY: 72 return SlotsPerVecY; 73 case Op_VecX: 74 return SlotsPerVecX; 75 case Op_VecD: 76 return SlotsPerVecD; 77 case Op_RegD: 78 case Op_RegL: 79 #ifdef _LP64 80 case Op_RegP: 81 #endif 82 return 2; 83 case Op_VecA: 84 assert(Matcher::supports_scalable_vector(), "does not support scalable vector"); 85 return SlotsPerVecA; 86 } 87 // Op_VecS and the rest ideal registers. 88 return 1; 89 } 90 91 int RegMask::num_registers(uint ireg, LRG &lrg) { 92 int n_regs = num_registers(ireg); 93 94 // assigned is OptoReg which is selected by register allocator 95 OptoReg::Name assigned = lrg.reg(); 96 assert(OptoReg::is_valid(assigned), "should be valid opto register"); 97 98 if (lrg.is_scalable() && OptoReg::is_stack(assigned)) { 99 n_regs = lrg.scalable_reg_slots(); 100 } 101 return n_regs; 102 } 103 104 // Clear out partial bits; leave only bit pairs 105 void RegMask::clear_to_pairs() { 106 assert(valid_watermarks(), "sanity"); 107 for (int i = _lwm; i <= _hwm; i++) { 108 int bits = _A[i]; 109 bits &= ((bits & 0x55555555)<<1); // 1 hi-bit set for each pair 110 bits |= (bits>>1); // Smear 1 hi-bit into a pair 111 _A[i] = bits; 112 } 113 assert(is_aligned_pairs(), "mask is not aligned, adjacent pairs"); 114 } 115 116 bool RegMask::is_misaligned_pair() const { 117 return Size() == 2 && !is_aligned_pairs(); 118 } 119 120 bool RegMask::is_aligned_pairs() const { 121 // Assert that the register mask contains only bit pairs. 122 assert(valid_watermarks(), "sanity"); 123 for (int i = _lwm; i <= _hwm; i++) { 124 int bits = _A[i]; 125 while (bits) { // Check bits for pairing 126 int bit = bits & -bits; // Extract low bit 127 // Low bit is not odd means its mis-aligned. 128 if ((bit & 0x55555555) == 0) return false; 129 bits -= bit; // Remove bit from mask 130 // Check for aligned adjacent bit 131 if ((bits & (bit<<1)) == 0) return false; 132 bits -= (bit<<1); // Remove other halve of pair 133 } 134 } 135 return true; 136 } 137 138 // Return TRUE if the mask contains a single bit 139 bool RegMask::is_bound1() const { 140 if (is_AllStack()) return false; 141 return Size() == 1; 142 } 143 144 // Return TRUE if the mask contains an adjacent pair of bits and no other bits. 145 bool RegMask::is_bound_pair() const { 146 if (is_AllStack()) return false; 147 int bit = -1; // Set to hold the one bit allowed 148 assert(valid_watermarks(), "sanity"); 149 for (int i = _lwm; i <= _hwm; i++) { 150 if (_A[i]) { // Found some bits 151 if (bit != -1) return false; // Already had bits, so fail 152 bit = _A[i] & -(_A[i]); // Extract 1 bit from mask 153 if ((bit << 1) != 0) { // Bit pair stays in same word? 154 if ((bit | (bit<<1)) != _A[i]) 155 return false; // Require adjacent bit pair and no more bits 156 } else { // Else its a split-pair case 157 if(bit != _A[i]) return false; // Found many bits, so fail 158 i++; // Skip iteration forward 159 if (i > _hwm || _A[i] != 1) 160 return false; // Require 1 lo bit in next word 161 } 162 } 163 } 164 // True for both the empty mask and for a bit pair 165 return true; 166 } 167 168 // Test for a single adjacent set of ideal register's size. 169 bool RegMask::is_bound(uint ireg) const { 170 if (is_vector(ireg)) { 171 if (is_bound_set(num_registers(ireg))) 172 return true; 173 } else if (is_bound1() || is_bound_pair()) { 174 return true; 175 } 176 return false; 177 } 178 // Check that whether given reg number with size is valid 179 // for current regmask, where reg is the highest number. 180 bool RegMask::is_valid_reg(OptoReg::Name reg, const int size) const { 181 for (int i = 0; i < size; i++) { 182 if (!Member(reg - i)) { 183 return false; 184 } 185 } 186 return true; 187 } 188 189 // only indicies of power 2 are accessed, so index 3 is only filled in for storage. 190 static int low_bits[5] = { 0x55555555, 0x11111111, 0x01010101, 0x00000000, 0x00010001 }; 191 192 // Find the lowest-numbered register set in the mask. Return the 193 // HIGHEST register number in the set, or BAD if no sets. 194 // Works also for size 1. 195 OptoReg::Name RegMask::find_first_set(LRG &lrg, const int size) const { 196 if (lrg.is_scalable()) { 197 // For scalable vector register, regmask is SlotsPerVecA bits aligned. 198 assert(is_aligned_sets(SlotsPerVecA), "mask is not aligned, adjacent sets"); 199 } else { 200 assert(is_aligned_sets(size), "mask is not aligned, adjacent sets"); 201 } 202 assert(valid_watermarks(), "sanity"); 203 for (int i = _lwm; i <= _hwm; i++) { 204 if (_A[i]) { // Found some bits 205 // Convert to bit number, return hi bit in pair 206 return OptoReg::Name((i<<_LogWordBits) + find_lowest_bit(_A[i]) + (size - 1)); 207 } 208 } 209 return OptoReg::Bad; 210 } 211 212 // Clear out partial bits; leave only aligned adjacent bit pairs 213 void RegMask::clear_to_sets(const int size) { 214 if (size == 1) return; 215 assert(2 <= size && size <= 16, "update low bits table"); 216 assert(is_power_of_2(size), "sanity"); 217 assert(valid_watermarks(), "sanity"); 218 int low_bits_mask = low_bits[size>>2]; 219 for (int i = _lwm; i <= _hwm; i++) { 220 int bits = _A[i]; 221 int sets = (bits & low_bits_mask); 222 for (int j = 1; j < size; j++) { 223 sets = (bits & (sets<<1)); // filter bits which produce whole sets 224 } 225 sets |= (sets>>1); // Smear 1 hi-bit into a set 226 if (size > 2) { 227 sets |= (sets>>2); // Smear 2 hi-bits into a set 228 if (size > 4) { 229 sets |= (sets>>4); // Smear 4 hi-bits into a set 230 if (size > 8) { 231 sets |= (sets>>8); // Smear 8 hi-bits into a set 232 } 233 } 234 } 235 _A[i] = sets; 236 } 237 assert(is_aligned_sets(size), "mask is not aligned, adjacent sets"); 238 } 239 240 // Smear out partial bits to aligned adjacent bit sets 241 void RegMask::smear_to_sets(const int size) { 242 if (size == 1) return; 243 assert(2 <= size && size <= 16, "update low bits table"); 244 assert(is_power_of_2(size), "sanity"); 245 assert(valid_watermarks(), "sanity"); 246 int low_bits_mask = low_bits[size>>2]; 247 for (int i = _lwm; i <= _hwm; i++) { 248 int bits = _A[i]; 249 int sets = 0; 250 for (int j = 0; j < size; j++) { 251 sets |= (bits & low_bits_mask); // collect partial bits 252 bits = bits>>1; 253 } 254 sets |= (sets<<1); // Smear 1 lo-bit into a set 255 if (size > 2) { 256 sets |= (sets<<2); // Smear 2 lo-bits into a set 257 if (size > 4) { 258 sets |= (sets<<4); // Smear 4 lo-bits into a set 259 if (size > 8) { 260 sets |= (sets<<8); // Smear 8 lo-bits into a set 261 } 262 } 263 } 264 _A[i] = sets; 265 } 266 assert(is_aligned_sets(size), "mask is not aligned, adjacent sets"); 267 } 268 269 // Assert that the register mask contains only bit sets. 270 bool RegMask::is_aligned_sets(const int size) const { 271 if (size == 1) return true; 272 assert(2 <= size && size <= 16, "update low bits table"); 273 assert(is_power_of_2(size), "sanity"); 274 int low_bits_mask = low_bits[size>>2]; 275 assert(valid_watermarks(), "sanity"); 276 for (int i = _lwm; i <= _hwm; i++) { 277 int bits = _A[i]; 278 while (bits) { // Check bits for pairing 279 int bit = bits & -bits; // Extract low bit 280 // Low bit is not odd means its mis-aligned. 281 if ((bit & low_bits_mask) == 0) { 282 return false; 283 } 284 // Do extra work since (bit << size) may overflow. 285 int hi_bit = bit << (size-1); // high bit 286 int set = hi_bit + ((hi_bit-1) & ~(bit-1)); 287 // Check for aligned adjacent bits in this set 288 if ((bits & set) != set) { 289 return false; 290 } 291 bits -= set; // Remove this set 292 } 293 } 294 return true; 295 } 296 297 // Return TRUE if the mask contains one adjacent set of bits and no other bits. 298 // Works also for size 1. 299 int RegMask::is_bound_set(const int size) const { 300 if (is_AllStack()) return false; 301 assert(1 <= size && size <= 16, "update low bits table"); 302 assert(valid_watermarks(), "sanity"); 303 int bit = -1; // Set to hold the one bit allowed 304 for (int i = _lwm; i <= _hwm; i++) { 305 if (_A[i] ) { // Found some bits 306 if (bit != -1) 307 return false; // Already had bits, so fail 308 bit = _A[i] & -_A[i]; // Extract low bit from mask 309 int hi_bit = bit << (size-1); // high bit 310 if (hi_bit != 0) { // Bit set stays in same word? 311 int set = hi_bit + ((hi_bit-1) & ~(bit-1)); 312 if (set != _A[i]) 313 return false; // Require adjacent bit set and no more bits 314 } else { // Else its a split-set case 315 if (((-1) & ~(bit-1)) != _A[i]) 316 return false; // Found many bits, so fail 317 i++; // Skip iteration forward and check high part 318 // The lower (32-size) bits should be 0 since it is split case. 319 int clear_bit_size = 32-size; 320 int shift_back_size = 32-clear_bit_size; 321 int set = bit>>clear_bit_size; 322 set = set & -set; // Remove sign extension. 323 set = (((set << size) - 1) >> shift_back_size); 324 if (i > _hwm || _A[i] != set) 325 return false; // Require expected low bits in next word 326 } 327 } 328 } 329 // True for both the empty mask and for a bit set 330 return true; 331 } 332 333 // UP means register only, Register plus stack, or stack only is DOWN 334 bool RegMask::is_UP() const { 335 // Quick common case check for DOWN (any stack slot is legal) 336 if (is_AllStack()) 337 return false; 338 // Slower check for any stack bits set (also DOWN) 339 if (overlap(Matcher::STACK_ONLY_mask)) 340 return false; 341 // Not DOWN, so must be UP 342 return true; 343 } 344 345 // Compute size of register mask in bits 346 uint RegMask::Size() const { 347 uint sum = 0; 348 assert(valid_watermarks(), "sanity"); 349 for (int i = _lwm; i <= _hwm; i++) { 350 sum += population_count((unsigned)_A[i]); 351 } 352 return sum; 353 } 354 355 #ifndef PRODUCT 356 void RegMask::dump(outputStream *st) const { 357 st->print("["); 358 RegMask rm = *this; // Structure copy into local temp 359 360 OptoReg::Name start = rm.find_first_elem(); // Get a register 361 if (OptoReg::is_valid(start)) { // Check for empty mask 362 rm.Remove(start); // Yank from mask 363 OptoReg::dump(start, st); // Print register 364 OptoReg::Name last = start; 365 366 // Now I have printed an initial register. 367 // Print adjacent registers as "rX-rZ" instead of "rX,rY,rZ". 368 // Begin looping over the remaining registers. 369 while (1) { // 370 OptoReg::Name reg = rm.find_first_elem(); // Get a register 371 if (!OptoReg::is_valid(reg)) 372 break; // Empty mask, end loop 373 rm.Remove(reg); // Yank from mask 374 375 if (last+1 == reg) { // See if they are adjacent 376 // Adjacent registers just collect into long runs, no printing. 377 last = reg; 378 } else { // Ending some kind of run 379 if (start == last) { // 1-register run; no special printing 380 } else if (start+1 == last) { 381 st->print(","); // 2-register run; print as "rX,rY" 382 OptoReg::dump(last, st); 383 } else { // Multi-register run; print as "rX-rZ" 384 st->print("-"); 385 OptoReg::dump(last, st); 386 } 387 st->print(","); // Seperate start of new run 388 start = last = reg; // Start a new register run 389 OptoReg::dump(start, st); // Print register 390 } // End of if ending a register run or not 391 } // End of while regmask not empty 392 393 if (start == last) { // 1-register run; no special printing 394 } else if (start+1 == last) { 395 st->print(","); // 2-register run; print as "rX,rY" 396 OptoReg::dump(last, st); 397 } else { // Multi-register run; print as "rX-rZ" 398 st->print("-"); 399 OptoReg::dump(last, st); 400 } 401 if (rm.is_AllStack()) st->print("..."); 402 } 403 st->print("]"); 404 } 405 #endif