Mercurial > hg > truffle
annotate src/share/vm/opto/buildOopMap.cpp @ 985:685e959d09ea
6877254: Server vm crashes with no branches off of store slice" when run with CMS and UseSuperWord(default)
Summary: design StoreCMNode::Ideal to promote its oopStore input if the input is a MergeMem node
Reviewed-by: kvn, never
| author | cfang |
|---|---|
| date | Mon, 14 Sep 2009 09:49:54 -0700 |
| parents | bd02caa94611 |
| children | c18cbe5936b8 |
| rev | line source |
|---|---|
| 0 | 1 /* |
| 844 | 2 * Copyright 2002-2009 Sun Microsystems, Inc. All Rights Reserved. |
| 0 | 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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara, | |
| 20 * CA 95054 USA or visit www.sun.com if you need additional information or | |
| 21 * have any questions. | |
| 22 * | |
| 23 */ | |
| 24 | |
| 25 #include "incls/_precompiled.incl" | |
| 26 #include "incls/_buildOopMap.cpp.incl" | |
| 27 | |
| 28 // The functions in this file builds OopMaps after all scheduling is done. | |
| 29 // | |
| 30 // OopMaps contain a list of all registers and stack-slots containing oops (so | |
| 31 // they can be updated by GC). OopMaps also contain a list of derived-pointer | |
| 32 // base-pointer pairs. When the base is moved, the derived pointer moves to | |
| 33 // follow it. Finally, any registers holding callee-save values are also | |
| 34 // recorded. These might contain oops, but only the caller knows. | |
| 35 // | |
| 36 // BuildOopMaps implements a simple forward reaching-defs solution. At each | |
| 37 // GC point we'll have the reaching-def Nodes. If the reaching Nodes are | |
| 38 // typed as pointers (no offset), then they are oops. Pointers+offsets are | |
| 39 // derived pointers, and bases can be found from them. Finally, we'll also | |
| 40 // track reaching callee-save values. Note that a copy of a callee-save value | |
| 41 // "kills" it's source, so that only 1 copy of a callee-save value is alive at | |
| 42 // a time. | |
| 43 // | |
| 44 // We run a simple bitvector liveness pass to help trim out dead oops. Due to | |
| 45 // irreducible loops, we can have a reaching def of an oop that only reaches | |
| 46 // along one path and no way to know if it's valid or not on the other path. | |
| 47 // The bitvectors are quite dense and the liveness pass is fast. | |
| 48 // | |
| 49 // At GC points, we consult this information to build OopMaps. All reaching | |
| 50 // defs typed as oops are added to the OopMap. Only 1 instance of a | |
| 51 // callee-save register can be recorded. For derived pointers, we'll have to | |
| 52 // find and record the register holding the base. | |
| 53 // | |
| 54 // The reaching def's is a simple 1-pass worklist approach. I tried a clever | |
| 55 // breadth-first approach but it was worse (showed O(n^2) in the | |
| 56 // pick-next-block code). | |
| 57 // | |
| 605 | 58 // The relevant data is kept in a struct of arrays (it could just as well be |
| 0 | 59 // an array of structs, but the struct-of-arrays is generally a little more |
| 60 // efficient). The arrays are indexed by register number (including | |
| 61 // stack-slots as registers) and so is bounded by 200 to 300 elements in | |
| 62 // practice. One array will map to a reaching def Node (or NULL for | |
| 63 // conflict/dead). The other array will map to a callee-saved register or | |
| 64 // OptoReg::Bad for not-callee-saved. | |
| 65 | |
| 66 | |
| 67 //------------------------------OopFlow---------------------------------------- | |
| 68 // Structure to pass around | |
| 69 struct OopFlow : public ResourceObj { | |
| 70 short *_callees; // Array mapping register to callee-saved | |
| 71 Node **_defs; // array mapping register to reaching def | |
| 72 // or NULL if dead/conflict | |
| 73 // OopFlow structs, when not being actively modified, describe the _end_ of | |
| 74 // this block. | |
| 75 Block *_b; // Block for this struct | |
| 76 OopFlow *_next; // Next free OopFlow | |
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77 // or NULL if dead/conflict |
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78 Compile* C; |
| 0 | 79 |
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80 OopFlow( short *callees, Node **defs, Compile* c ) : _callees(callees), _defs(defs), |
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81 _b(NULL), _next(NULL), C(c) { } |
| 0 | 82 |
| 83 // Given reaching-defs for this block start, compute it for this block end | |
| 84 void compute_reach( PhaseRegAlloc *regalloc, int max_reg, Dict *safehash ); | |
| 85 | |
| 86 // Merge these two OopFlows into the 'this' pointer. | |
| 87 void merge( OopFlow *flow, int max_reg ); | |
| 88 | |
| 89 // Copy a 'flow' over an existing flow | |
| 90 void clone( OopFlow *flow, int max_size); | |
| 91 | |
| 92 // Make a new OopFlow from scratch | |
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93 static OopFlow *make( Arena *A, int max_size, Compile* C ); |
| 0 | 94 |
| 95 // Build an oopmap from the current flow info | |
| 96 OopMap *build_oop_map( Node *n, int max_reg, PhaseRegAlloc *regalloc, int* live ); | |
| 97 }; | |
| 98 | |
| 99 //------------------------------compute_reach---------------------------------- | |
| 100 // Given reaching-defs for this block start, compute it for this block end | |
| 101 void OopFlow::compute_reach( PhaseRegAlloc *regalloc, int max_reg, Dict *safehash ) { | |
| 102 | |
| 103 for( uint i=0; i<_b->_nodes.size(); i++ ) { | |
| 104 Node *n = _b->_nodes[i]; | |
| 105 | |
| 106 if( n->jvms() ) { // Build an OopMap here? | |
| 107 JVMState *jvms = n->jvms(); | |
| 108 // no map needed for leaf calls | |
| 109 if( n->is_MachSafePoint() && !n->is_MachCallLeaf() ) { | |
| 110 int *live = (int*) (*safehash)[n]; | |
| 111 assert( live, "must find live" ); | |
| 112 n->as_MachSafePoint()->set_oop_map( build_oop_map(n,max_reg,regalloc, live) ); | |
| 113 } | |
| 114 } | |
| 115 | |
| 116 // Assign new reaching def's. | |
| 117 // Note that I padded the _defs and _callees arrays so it's legal | |
| 118 // to index at _defs[OptoReg::Bad]. | |
| 119 OptoReg::Name first = regalloc->get_reg_first(n); | |
| 120 OptoReg::Name second = regalloc->get_reg_second(n); | |
| 121 _defs[first] = n; | |
| 122 _defs[second] = n; | |
| 123 | |
| 124 // Pass callee-save info around copies | |
| 125 int idx = n->is_Copy(); | |
| 126 if( idx ) { // Copies move callee-save info | |
| 127 OptoReg::Name old_first = regalloc->get_reg_first(n->in(idx)); | |
| 128 OptoReg::Name old_second = regalloc->get_reg_second(n->in(idx)); | |
| 129 int tmp_first = _callees[old_first]; | |
| 130 int tmp_second = _callees[old_second]; | |
| 131 _callees[old_first] = OptoReg::Bad; // callee-save is moved, dead in old location | |
| 132 _callees[old_second] = OptoReg::Bad; | |
| 133 _callees[first] = tmp_first; | |
| 134 _callees[second] = tmp_second; | |
| 135 } else if( n->is_Phi() ) { // Phis do not mod callee-saves | |
| 136 assert( _callees[first] == _callees[regalloc->get_reg_first(n->in(1))], "" ); | |
| 137 assert( _callees[second] == _callees[regalloc->get_reg_second(n->in(1))], "" ); | |
| 138 assert( _callees[first] == _callees[regalloc->get_reg_first(n->in(n->req()-1))], "" ); | |
| 139 assert( _callees[second] == _callees[regalloc->get_reg_second(n->in(n->req()-1))], "" ); | |
| 140 } else { | |
| 141 _callees[first] = OptoReg::Bad; // No longer holding a callee-save value | |
| 142 _callees[second] = OptoReg::Bad; | |
| 143 | |
| 144 // Find base case for callee saves | |
| 145 if( n->is_Proj() && n->in(0)->is_Start() ) { | |
| 146 if( OptoReg::is_reg(first) && | |
| 147 regalloc->_matcher.is_save_on_entry(first) ) | |
| 148 _callees[first] = first; | |
| 149 if( OptoReg::is_reg(second) && | |
| 150 regalloc->_matcher.is_save_on_entry(second) ) | |
| 151 _callees[second] = second; | |
| 152 } | |
| 153 } | |
| 154 } | |
| 155 } | |
| 156 | |
| 157 //------------------------------merge------------------------------------------ | |
| 158 // Merge the given flow into the 'this' flow | |
| 159 void OopFlow::merge( OopFlow *flow, int max_reg ) { | |
| 160 assert( _b == NULL, "merging into a happy flow" ); | |
| 161 assert( flow->_b, "this flow is still alive" ); | |
| 162 assert( flow != this, "no self flow" ); | |
| 163 | |
| 164 // Do the merge. If there are any differences, drop to 'bottom' which | |
| 165 // is OptoReg::Bad or NULL depending. | |
| 166 for( int i=0; i<max_reg; i++ ) { | |
| 167 // Merge the callee-save's | |
| 168 if( _callees[i] != flow->_callees[i] ) | |
| 169 _callees[i] = OptoReg::Bad; | |
| 170 // Merge the reaching defs | |
| 171 if( _defs[i] != flow->_defs[i] ) | |
| 172 _defs[i] = NULL; | |
| 173 } | |
| 174 | |
| 175 } | |
| 176 | |
| 177 //------------------------------clone------------------------------------------ | |
| 178 void OopFlow::clone( OopFlow *flow, int max_size ) { | |
| 179 _b = flow->_b; | |
| 180 memcpy( _callees, flow->_callees, sizeof(short)*max_size); | |
| 181 memcpy( _defs , flow->_defs , sizeof(Node*)*max_size); | |
| 182 } | |
| 183 | |
| 184 //------------------------------make------------------------------------------- | |
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185 OopFlow *OopFlow::make( Arena *A, int max_size, Compile* C ) { |
| 0 | 186 short *callees = NEW_ARENA_ARRAY(A,short,max_size+1); |
| 187 Node **defs = NEW_ARENA_ARRAY(A,Node*,max_size+1); | |
| 188 debug_only( memset(defs,0,(max_size+1)*sizeof(Node*)) ); | |
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189 OopFlow *flow = new (A) OopFlow(callees+1, defs+1, C); |
| 0 | 190 assert( &flow->_callees[OptoReg::Bad] == callees, "Ok to index at OptoReg::Bad" ); |
| 191 assert( &flow->_defs [OptoReg::Bad] == defs , "Ok to index at OptoReg::Bad" ); | |
| 192 return flow; | |
| 193 } | |
| 194 | |
| 195 //------------------------------bit twiddlers---------------------------------- | |
| 196 static int get_live_bit( int *live, int reg ) { | |
| 197 return live[reg>>LogBitsPerInt] & (1<<(reg&(BitsPerInt-1))); } | |
| 198 static void set_live_bit( int *live, int reg ) { | |
| 199 live[reg>>LogBitsPerInt] |= (1<<(reg&(BitsPerInt-1))); } | |
| 200 static void clr_live_bit( int *live, int reg ) { | |
| 201 live[reg>>LogBitsPerInt] &= ~(1<<(reg&(BitsPerInt-1))); } | |
| 202 | |
| 203 //------------------------------build_oop_map---------------------------------- | |
| 204 // Build an oopmap from the current flow info | |
| 205 OopMap *OopFlow::build_oop_map( Node *n, int max_reg, PhaseRegAlloc *regalloc, int* live ) { | |
| 206 int framesize = regalloc->_framesize; | |
| 207 int max_inarg_slot = OptoReg::reg2stack(regalloc->_matcher._new_SP); | |
| 208 debug_only( char *dup_check = NEW_RESOURCE_ARRAY(char,OptoReg::stack0()); | |
| 209 memset(dup_check,0,OptoReg::stack0()) ); | |
| 210 | |
| 211 OopMap *omap = new OopMap( framesize, max_inarg_slot ); | |
| 212 MachCallNode *mcall = n->is_MachCall() ? n->as_MachCall() : NULL; | |
| 213 JVMState* jvms = n->jvms(); | |
| 214 | |
| 215 // For all registers do... | |
| 216 for( int reg=0; reg<max_reg; reg++ ) { | |
| 217 if( get_live_bit(live,reg) == 0 ) | |
| 218 continue; // Ignore if not live | |
| 219 | |
| 220 // %%% C2 can use 2 OptoRegs when the physical register is only one 64bit | |
| 221 // register in that case we'll get an non-concrete register for the second | |
| 222 // half. We only need to tell the map the register once! | |
| 223 // | |
| 224 // However for the moment we disable this change and leave things as they | |
| 225 // were. | |
| 226 | |
| 227 VMReg r = OptoReg::as_VMReg(OptoReg::Name(reg), framesize, max_inarg_slot); | |
| 228 | |
| 229 if (false && r->is_reg() && !r->is_concrete()) { | |
| 230 continue; | |
| 231 } | |
| 232 | |
| 233 // See if dead (no reaching def). | |
| 234 Node *def = _defs[reg]; // Get reaching def | |
| 235 assert( def, "since live better have reaching def" ); | |
| 236 | |
| 237 // Classify the reaching def as oop, derived, callee-save, dead, or other | |
| 238 const Type *t = def->bottom_type(); | |
| 239 if( t->isa_oop_ptr() ) { // Oop or derived? | |
| 240 assert( !OptoReg::is_valid(_callees[reg]), "oop can't be callee save" ); | |
| 241 #ifdef _LP64 | |
| 242 // 64-bit pointers record oop-ishness on 2 aligned adjacent registers. | |
| 243 // Make sure both are record from the same reaching def, but do not | |
| 244 // put both into the oopmap. | |
| 245 if( (reg&1) == 1 ) { // High half of oop-pair? | |
| 246 assert( _defs[reg-1] == _defs[reg], "both halves from same reaching def" ); | |
| 247 continue; // Do not record high parts in oopmap | |
| 248 } | |
| 249 #endif | |
| 250 | |
| 251 // Check for a legal reg name in the oopMap and bailout if it is not. | |
| 252 if (!omap->legal_vm_reg_name(r)) { | |
| 253 regalloc->C->record_method_not_compilable("illegal oopMap register name"); | |
| 254 continue; | |
| 255 } | |
| 256 if( t->is_ptr()->_offset == 0 ) { // Not derived? | |
| 257 if( mcall ) { | |
| 258 // Outgoing argument GC mask responsibility belongs to the callee, | |
| 259 // not the caller. Inspect the inputs to the call, to see if | |
| 260 // this live-range is one of them. | |
| 261 uint cnt = mcall->tf()->domain()->cnt(); | |
| 262 uint j; | |
| 263 for( j = TypeFunc::Parms; j < cnt; j++) | |
| 264 if( mcall->in(j) == def ) | |
| 265 break; // reaching def is an argument oop | |
| 266 if( j < cnt ) // arg oops dont go in GC map | |
| 267 continue; // Continue on to the next register | |
| 268 } | |
| 269 omap->set_oop(r); | |
| 270 } else { // Else it's derived. | |
| 271 // Find the base of the derived value. | |
| 272 uint i; | |
| 273 // Fast, common case, scan | |
| 274 for( i = jvms->oopoff(); i < n->req(); i+=2 ) | |
| 275 if( n->in(i) == def ) break; // Common case | |
| 276 if( i == n->req() ) { // Missed, try a more generous scan | |
| 277 // Scan again, but this time peek through copies | |
| 278 for( i = jvms->oopoff(); i < n->req(); i+=2 ) { | |
| 279 Node *m = n->in(i); // Get initial derived value | |
| 280 while( 1 ) { | |
| 281 Node *d = def; // Get initial reaching def | |
| 282 while( 1 ) { // Follow copies of reaching def to end | |
| 283 if( m == d ) goto found; // breaks 3 loops | |
| 284 int idx = d->is_Copy(); | |
| 285 if( !idx ) break; | |
| 286 d = d->in(idx); // Link through copy | |
| 287 } | |
| 288 int idx = m->is_Copy(); | |
| 289 if( !idx ) break; | |
| 290 m = m->in(idx); | |
| 291 } | |
| 292 } | |
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293 guarantee( 0, "must find derived/base pair" ); |
| 0 | 294 } |
| 295 found: ; | |
| 296 Node *base = n->in(i+1); // Base is other half of pair | |
| 297 int breg = regalloc->get_reg_first(base); | |
| 298 VMReg b = OptoReg::as_VMReg(OptoReg::Name(breg), framesize, max_inarg_slot); | |
| 299 | |
| 300 // I record liveness at safepoints BEFORE I make the inputs | |
| 301 // live. This is because argument oops are NOT live at a | |
| 302 // safepoint (or at least they cannot appear in the oopmap). | |
| 303 // Thus bases of base/derived pairs might not be in the | |
| 304 // liveness data but they need to appear in the oopmap. | |
| 305 if( get_live_bit(live,breg) == 0 ) {// Not live? | |
| 306 // Flag it, so next derived pointer won't re-insert into oopmap | |
| 307 set_live_bit(live,breg); | |
| 308 // Already missed our turn? | |
| 309 if( breg < reg ) { | |
| 310 if (b->is_stack() || b->is_concrete() || true ) { | |
| 311 omap->set_oop( b); | |
| 312 } | |
| 313 } | |
| 314 } | |
| 315 if (b->is_stack() || b->is_concrete() || true ) { | |
| 316 omap->set_derived_oop( r, b); | |
| 317 } | |
| 318 } | |
| 319 | |
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320 } else if( t->isa_narrowoop() ) { |
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321 assert( !OptoReg::is_valid(_callees[reg]), "oop can't be callee save" ); |
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322 // Check for a legal reg name in the oopMap and bailout if it is not. |
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323 if (!omap->legal_vm_reg_name(r)) { |
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324 regalloc->C->record_method_not_compilable("illegal oopMap register name"); |
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325 continue; |
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326 } |
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327 if( mcall ) { |
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328 // Outgoing argument GC mask responsibility belongs to the callee, |
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329 // not the caller. Inspect the inputs to the call, to see if |
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330 // this live-range is one of them. |
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331 uint cnt = mcall->tf()->domain()->cnt(); |
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332 uint j; |
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333 for( j = TypeFunc::Parms; j < cnt; j++) |
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334 if( mcall->in(j) == def ) |
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335 break; // reaching def is an argument oop |
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336 if( j < cnt ) // arg oops dont go in GC map |
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337 continue; // Continue on to the next register |
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338 } |
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339 omap->set_narrowoop(r); |
| 0 | 340 } else if( OptoReg::is_valid(_callees[reg])) { // callee-save? |
| 341 // It's a callee-save value | |
| 342 assert( dup_check[_callees[reg]]==0, "trying to callee save same reg twice" ); | |
| 343 debug_only( dup_check[_callees[reg]]=1; ) | |
| 344 VMReg callee = OptoReg::as_VMReg(OptoReg::Name(_callees[reg])); | |
| 345 if ( callee->is_concrete() || true ) { | |
| 346 omap->set_callee_saved( r, callee); | |
| 347 } | |
| 348 | |
| 349 } else { | |
| 350 // Other - some reaching non-oop value | |
| 351 omap->set_value( r); | |
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352 #ifdef ASSERT |
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353 if( t->isa_rawptr() && C->cfg()->_raw_oops.member(def) ) { |
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354 def->dump(); |
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355 n->dump(); |
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356 assert(false, "there should be a oop in OopMap instead of a live raw oop at safepoint"); |
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357 } |
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358 #endif |
| 0 | 359 } |
| 360 | |
| 361 } | |
| 362 | |
| 363 #ifdef ASSERT | |
| 364 /* Nice, Intel-only assert | |
| 365 int cnt_callee_saves=0; | |
| 366 int reg2 = 0; | |
| 367 while (OptoReg::is_reg(reg2)) { | |
| 368 if( dup_check[reg2] != 0) cnt_callee_saves++; | |
| 369 assert( cnt_callee_saves==3 || cnt_callee_saves==5, "missed some callee-save" ); | |
| 370 reg2++; | |
| 371 } | |
| 372 */ | |
| 373 #endif | |
| 374 | |
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375 #ifdef ASSERT |
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376 for( OopMapStream oms1(omap, OopMapValue::derived_oop_value); !oms1.is_done(); oms1.next()) { |
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377 OopMapValue omv1 = oms1.current(); |
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378 bool found = false; |
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379 for( OopMapStream oms2(omap,OopMapValue::oop_value); !oms2.is_done(); oms2.next()) { |
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380 if( omv1.content_reg() == oms2.current().reg() ) { |
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381 found = true; |
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382 break; |
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383 } |
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384 } |
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385 assert( found, "derived with no base in oopmap" ); |
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386 } |
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387 #endif |
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388 |
| 0 | 389 return omap; |
| 390 } | |
| 391 | |
| 392 //------------------------------do_liveness------------------------------------ | |
| 393 // Compute backwards liveness on registers | |
| 394 static void do_liveness( PhaseRegAlloc *regalloc, PhaseCFG *cfg, Block_List *worklist, int max_reg_ints, Arena *A, Dict *safehash ) { | |
| 395 int *live = NEW_ARENA_ARRAY(A, int, (cfg->_num_blocks+1) * max_reg_ints); | |
| 396 int *tmp_live = &live[cfg->_num_blocks * max_reg_ints]; | |
| 397 Node *root = cfg->C->root(); | |
| 398 // On CISC platforms, get the node representing the stack pointer that regalloc | |
| 399 // used for spills | |
| 400 Node *fp = NodeSentinel; | |
| 401 if (UseCISCSpill && root->req() > 1) { | |
| 402 fp = root->in(1)->in(TypeFunc::FramePtr); | |
| 403 } | |
| 404 memset( live, 0, cfg->_num_blocks * (max_reg_ints<<LogBytesPerInt) ); | |
| 405 // Push preds onto worklist | |
| 406 for( uint i=1; i<root->req(); i++ ) | |
| 407 worklist->push(cfg->_bbs[root->in(i)->_idx]); | |
| 408 | |
| 409 // ZKM.jar includes tiny infinite loops which are unreached from below. | |
| 410 // If we missed any blocks, we'll retry here after pushing all missed | |
| 411 // blocks on the worklist. Normally this outer loop never trips more | |
| 412 // than once. | |
| 413 while( 1 ) { | |
| 414 | |
| 415 while( worklist->size() ) { // Standard worklist algorithm | |
| 416 Block *b = worklist->rpop(); | |
| 417 | |
| 418 // Copy first successor into my tmp_live space | |
| 419 int s0num = b->_succs[0]->_pre_order; | |
| 420 int *t = &live[s0num*max_reg_ints]; | |
| 421 for( int i=0; i<max_reg_ints; i++ ) | |
| 422 tmp_live[i] = t[i]; | |
| 423 | |
| 424 // OR in the remaining live registers | |
| 425 for( uint j=1; j<b->_num_succs; j++ ) { | |
| 426 uint sjnum = b->_succs[j]->_pre_order; | |
| 427 int *t = &live[sjnum*max_reg_ints]; | |
| 428 for( int i=0; i<max_reg_ints; i++ ) | |
| 429 tmp_live[i] |= t[i]; | |
| 430 } | |
| 431 | |
| 432 // Now walk tmp_live up the block backwards, computing live | |
| 433 for( int k=b->_nodes.size()-1; k>=0; k-- ) { | |
| 434 Node *n = b->_nodes[k]; | |
| 435 // KILL def'd bits | |
| 436 int first = regalloc->get_reg_first(n); | |
| 437 int second = regalloc->get_reg_second(n); | |
| 438 if( OptoReg::is_valid(first) ) clr_live_bit(tmp_live,first); | |
| 439 if( OptoReg::is_valid(second) ) clr_live_bit(tmp_live,second); | |
| 440 | |
| 441 MachNode *m = n->is_Mach() ? n->as_Mach() : NULL; | |
| 442 | |
| 443 // Check if m is potentially a CISC alternate instruction (i.e, possibly | |
| 444 // synthesized by RegAlloc from a conventional instruction and a | |
| 445 // spilled input) | |
| 446 bool is_cisc_alternate = false; | |
| 447 if (UseCISCSpill && m) { | |
| 448 is_cisc_alternate = m->is_cisc_alternate(); | |
| 449 } | |
| 450 | |
| 451 // GEN use'd bits | |
| 452 for( uint l=1; l<n->req(); l++ ) { | |
| 453 Node *def = n->in(l); | |
| 454 assert(def != 0, "input edge required"); | |
| 455 int first = regalloc->get_reg_first(def); | |
| 456 int second = regalloc->get_reg_second(def); | |
| 457 if( OptoReg::is_valid(first) ) set_live_bit(tmp_live,first); | |
| 458 if( OptoReg::is_valid(second) ) set_live_bit(tmp_live,second); | |
| 459 // If we use the stack pointer in a cisc-alternative instruction, | |
| 460 // check for use as a memory operand. Then reconstruct the RegName | |
| 461 // for this stack location, and set the appropriate bit in the | |
| 462 // live vector 4987749. | |
| 463 if (is_cisc_alternate && def == fp) { | |
| 464 const TypePtr *adr_type = NULL; | |
| 465 intptr_t offset; | |
| 466 const Node* base = m->get_base_and_disp(offset, adr_type); | |
| 467 if (base == NodeSentinel) { | |
| 468 // Machnode has multiple memory inputs. We are unable to reason | |
| 469 // with these, but are presuming (with trepidation) that not any of | |
| 470 // them are oops. This can be fixed by making get_base_and_disp() | |
| 471 // look at a specific input instead of all inputs. | |
| 472 assert(!def->bottom_type()->isa_oop_ptr(), "expecting non-oop mem input"); | |
| 473 } else if (base != fp || offset == Type::OffsetBot) { | |
| 474 // Do nothing: the fp operand is either not from a memory use | |
| 475 // (base == NULL) OR the fp is used in a non-memory context | |
| 476 // (base is some other register) OR the offset is not constant, | |
| 477 // so it is not a stack slot. | |
| 478 } else { | |
| 479 assert(offset >= 0, "unexpected negative offset"); | |
| 480 offset -= (offset % jintSize); // count the whole word | |
| 481 int stack_reg = regalloc->offset2reg(offset); | |
| 482 if (OptoReg::is_stack(stack_reg)) { | |
| 483 set_live_bit(tmp_live, stack_reg); | |
| 484 } else { | |
| 485 assert(false, "stack_reg not on stack?"); | |
| 486 } | |
| 487 } | |
| 488 } | |
| 489 } | |
| 490 | |
| 491 if( n->jvms() ) { // Record liveness at safepoint | |
| 492 | |
| 493 // This placement of this stanza means inputs to calls are | |
| 494 // considered live at the callsite's OopMap. Argument oops are | |
| 495 // hence live, but NOT included in the oopmap. See cutout in | |
| 496 // build_oop_map. Debug oops are live (and in OopMap). | |
| 497 int *n_live = NEW_ARENA_ARRAY(A, int, max_reg_ints); | |
| 498 for( int l=0; l<max_reg_ints; l++ ) | |
| 499 n_live[l] = tmp_live[l]; | |
| 500 safehash->Insert(n,n_live); | |
| 501 } | |
| 502 | |
| 503 } | |
| 504 | |
| 505 // Now at block top, see if we have any changes. If so, propagate | |
| 506 // to prior blocks. | |
| 507 int *old_live = &live[b->_pre_order*max_reg_ints]; | |
| 508 int l; | |
| 509 for( l=0; l<max_reg_ints; l++ ) | |
| 510 if( tmp_live[l] != old_live[l] ) | |
| 511 break; | |
| 512 if( l<max_reg_ints ) { // Change! | |
| 513 // Copy in new value | |
| 514 for( l=0; l<max_reg_ints; l++ ) | |
| 515 old_live[l] = tmp_live[l]; | |
| 516 // Push preds onto worklist | |
| 517 for( l=1; l<(int)b->num_preds(); l++ ) | |
| 518 worklist->push(cfg->_bbs[b->pred(l)->_idx]); | |
| 519 } | |
| 520 } | |
| 521 | |
| 522 // Scan for any missing safepoints. Happens to infinite loops | |
| 523 // ala ZKM.jar | |
| 524 uint i; | |
| 525 for( i=1; i<cfg->_num_blocks; i++ ) { | |
| 526 Block *b = cfg->_blocks[i]; | |
| 527 uint j; | |
| 528 for( j=1; j<b->_nodes.size(); j++ ) | |
| 529 if( b->_nodes[j]->jvms() && | |
| 530 (*safehash)[b->_nodes[j]] == NULL ) | |
| 531 break; | |
| 532 if( j<b->_nodes.size() ) break; | |
| 533 } | |
| 534 if( i == cfg->_num_blocks ) | |
| 535 break; // Got 'em all | |
| 536 #ifndef PRODUCT | |
| 537 if( PrintOpto && Verbose ) | |
| 538 tty->print_cr("retripping live calc"); | |
| 539 #endif | |
| 540 // Force the issue (expensively): recheck everybody | |
| 541 for( i=1; i<cfg->_num_blocks; i++ ) | |
| 542 worklist->push(cfg->_blocks[i]); | |
| 543 } | |
| 544 | |
| 545 } | |
| 546 | |
| 547 //------------------------------BuildOopMaps----------------------------------- | |
| 548 // Collect GC mask info - where are all the OOPs? | |
| 549 void Compile::BuildOopMaps() { | |
| 550 NOT_PRODUCT( TracePhase t3("bldOopMaps", &_t_buildOopMaps, TimeCompiler); ) | |
| 551 // Can't resource-mark because I need to leave all those OopMaps around, | |
| 552 // or else I need to resource-mark some arena other than the default. | |
| 553 // ResourceMark rm; // Reclaim all OopFlows when done | |
| 554 int max_reg = _regalloc->_max_reg; // Current array extent | |
| 555 | |
| 556 Arena *A = Thread::current()->resource_area(); | |
| 557 Block_List worklist; // Worklist of pending blocks | |
| 558 | |
| 559 int max_reg_ints = round_to(max_reg, BitsPerInt)>>LogBitsPerInt; | |
| 560 Dict *safehash = NULL; // Used for assert only | |
| 561 // Compute a backwards liveness per register. Needs a bitarray of | |
| 562 // #blocks x (#registers, rounded up to ints) | |
| 563 safehash = new Dict(cmpkey,hashkey,A); | |
| 564 do_liveness( _regalloc, _cfg, &worklist, max_reg_ints, A, safehash ); | |
| 565 OopFlow *free_list = NULL; // Free, unused | |
| 566 | |
| 567 // Array mapping blocks to completed oopflows | |
| 568 OopFlow **flows = NEW_ARENA_ARRAY(A, OopFlow*, _cfg->_num_blocks); | |
| 569 memset( flows, 0, _cfg->_num_blocks*sizeof(OopFlow*) ); | |
| 570 | |
| 571 | |
| 572 // Do the first block 'by hand' to prime the worklist | |
| 573 Block *entry = _cfg->_blocks[1]; | |
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574 OopFlow *rootflow = OopFlow::make(A,max_reg,this); |
| 0 | 575 // Initialize to 'bottom' (not 'top') |
| 576 memset( rootflow->_callees, OptoReg::Bad, max_reg*sizeof(short) ); | |
| 577 memset( rootflow->_defs , 0, max_reg*sizeof(Node*) ); | |
| 578 flows[entry->_pre_order] = rootflow; | |
| 579 | |
| 580 // Do the first block 'by hand' to prime the worklist | |
| 581 rootflow->_b = entry; | |
| 582 rootflow->compute_reach( _regalloc, max_reg, safehash ); | |
| 583 for( uint i=0; i<entry->_num_succs; i++ ) | |
| 584 worklist.push(entry->_succs[i]); | |
| 585 | |
| 586 // Now worklist contains blocks which have some, but perhaps not all, | |
| 587 // predecessors visited. | |
| 588 while( worklist.size() ) { | |
| 589 // Scan for a block with all predecessors visited, or any randoms slob | |
| 590 // otherwise. All-preds-visited order allows me to recycle OopFlow | |
| 591 // structures rapidly and cut down on the memory footprint. | |
| 592 // Note: not all predecessors might be visited yet (must happen for | |
| 593 // irreducible loops). This is OK, since every live value must have the | |
| 594 // SAME reaching def for the block, so any reaching def is OK. | |
| 595 uint i; | |
| 596 | |
| 597 Block *b = worklist.pop(); | |
| 598 // Ignore root block | |
| 599 if( b == _cfg->_broot ) continue; | |
| 600 // Block is already done? Happens if block has several predecessors, | |
| 601 // he can get on the worklist more than once. | |
| 602 if( flows[b->_pre_order] ) continue; | |
| 603 | |
| 604 // If this block has a visited predecessor AND that predecessor has this | |
| 605 // last block as his only undone child, we can move the OopFlow from the | |
| 606 // pred to this block. Otherwise we have to grab a new OopFlow. | |
| 607 OopFlow *flow = NULL; // Flag for finding optimized flow | |
| 608 Block *pred = (Block*)0xdeadbeef; | |
| 609 uint j; | |
| 610 // Scan this block's preds to find a done predecessor | |
| 611 for( j=1; j<b->num_preds(); j++ ) { | |
| 612 Block *p = _cfg->_bbs[b->pred(j)->_idx]; | |
| 613 OopFlow *p_flow = flows[p->_pre_order]; | |
| 614 if( p_flow ) { // Predecessor is done | |
| 615 assert( p_flow->_b == p, "cross check" ); | |
| 616 pred = p; // Record some predecessor | |
| 617 // If all successors of p are done except for 'b', then we can carry | |
| 618 // p_flow forward to 'b' without copying, otherwise we have to draw | |
| 619 // from the free_list and clone data. | |
| 620 uint k; | |
| 621 for( k=0; k<p->_num_succs; k++ ) | |
| 622 if( !flows[p->_succs[k]->_pre_order] && | |
| 623 p->_succs[k] != b ) | |
| 624 break; | |
| 625 | |
| 626 // Either carry-forward the now-unused OopFlow for b's use | |
| 627 // or draw a new one from the free list | |
| 628 if( k==p->_num_succs ) { | |
| 629 flow = p_flow; | |
| 630 break; // Found an ideal pred, use him | |
| 631 } | |
| 632 } | |
| 633 } | |
| 634 | |
| 635 if( flow ) { | |
| 636 // We have an OopFlow that's the last-use of a predecessor. | |
| 637 // Carry it forward. | |
| 638 } else { // Draw a new OopFlow from the freelist | |
| 639 if( !free_list ) | |
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640 free_list = OopFlow::make(A,max_reg,C); |
| 0 | 641 flow = free_list; |
| 642 assert( flow->_b == NULL, "oopFlow is not free" ); | |
| 643 free_list = flow->_next; | |
| 644 flow->_next = NULL; | |
| 645 | |
| 646 // Copy/clone over the data | |
| 647 flow->clone(flows[pred->_pre_order], max_reg); | |
| 648 } | |
| 649 | |
| 650 // Mark flow for block. Blocks can only be flowed over once, | |
| 651 // because after the first time they are guarded from entering | |
| 652 // this code again. | |
| 653 assert( flow->_b == pred, "have some prior flow" ); | |
| 654 flow->_b = NULL; | |
| 655 | |
| 656 // Now push flow forward | |
| 657 flows[b->_pre_order] = flow;// Mark flow for this block | |
| 658 flow->_b = b; | |
| 659 flow->compute_reach( _regalloc, max_reg, safehash ); | |
| 660 | |
| 661 // Now push children onto worklist | |
| 662 for( i=0; i<b->_num_succs; i++ ) | |
| 663 worklist.push(b->_succs[i]); | |
| 664 | |
| 665 } | |
| 666 } |