Mercurial > hg > truffle
annotate src/share/vm/opto/buildOopMap.cpp @ 1994:6cd6d394f280
7001033: assert(gch->gc_cause() == GCCause::_scavenge_alot || !gch->incremental_collection_failed())
7002546: regression on SpecJbb2005 on 7b118 comparing to 7b117 on small heaps
Summary: Relaxed assertion checking related to incremental_collection_failed flag to allow for ExplicitGCInvokesConcurrent behaviour where we do not want a failing scavenge to bail to a stop-world collection. Parameterized incremental_collection_will_fail() so we can selectively use, or not use, as appropriate, the statistical prediction at specific use sites. This essentially reverts the scavenge bail-out logic to what it was prior to some recent changes that had inadvertently started using the statistical prediction which can be noisy in the presence of bursty loads. Added some associated verbose non-product debugging messages.
Reviewed-by: johnc, tonyp
author | ysr |
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date | Tue, 07 Dec 2010 21:55:53 -0800 |
parents | f95d63e2154a |
children | b92c45f2bc75 |
rev | line source |
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0 | 1 /* |
1972 | 2 * Copyright (c) 2002, 2010, Oracle and/or its affiliates. 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 * | |
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19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA |
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20 * or visit www.oracle.com if you need additional information or have any |
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21 * questions. |
0 | 22 * |
23 */ | |
24 | |
1972 | 25 #include "precompiled.hpp" |
26 #include "compiler/oopMap.hpp" | |
27 #include "opto/addnode.hpp" | |
28 #include "opto/callnode.hpp" | |
29 #include "opto/compile.hpp" | |
30 #include "opto/machnode.hpp" | |
31 #include "opto/matcher.hpp" | |
32 #include "opto/phase.hpp" | |
33 #include "opto/regalloc.hpp" | |
34 #include "opto/rootnode.hpp" | |
35 #ifdef TARGET_ARCH_x86 | |
36 # include "vmreg_x86.inline.hpp" | |
37 #endif | |
38 #ifdef TARGET_ARCH_sparc | |
39 # include "vmreg_sparc.inline.hpp" | |
40 #endif | |
41 #ifdef TARGET_ARCH_zero | |
42 # include "vmreg_zero.inline.hpp" | |
43 #endif | |
0 | 44 |
45 // The functions in this file builds OopMaps after all scheduling is done. | |
46 // | |
47 // OopMaps contain a list of all registers and stack-slots containing oops (so | |
48 // they can be updated by GC). OopMaps also contain a list of derived-pointer | |
49 // base-pointer pairs. When the base is moved, the derived pointer moves to | |
50 // follow it. Finally, any registers holding callee-save values are also | |
51 // recorded. These might contain oops, but only the caller knows. | |
52 // | |
53 // BuildOopMaps implements a simple forward reaching-defs solution. At each | |
54 // GC point we'll have the reaching-def Nodes. If the reaching Nodes are | |
55 // typed as pointers (no offset), then they are oops. Pointers+offsets are | |
56 // derived pointers, and bases can be found from them. Finally, we'll also | |
57 // track reaching callee-save values. Note that a copy of a callee-save value | |
58 // "kills" it's source, so that only 1 copy of a callee-save value is alive at | |
59 // a time. | |
60 // | |
61 // We run a simple bitvector liveness pass to help trim out dead oops. Due to | |
62 // irreducible loops, we can have a reaching def of an oop that only reaches | |
63 // along one path and no way to know if it's valid or not on the other path. | |
64 // The bitvectors are quite dense and the liveness pass is fast. | |
65 // | |
66 // At GC points, we consult this information to build OopMaps. All reaching | |
67 // defs typed as oops are added to the OopMap. Only 1 instance of a | |
68 // callee-save register can be recorded. For derived pointers, we'll have to | |
69 // find and record the register holding the base. | |
70 // | |
71 // The reaching def's is a simple 1-pass worklist approach. I tried a clever | |
72 // breadth-first approach but it was worse (showed O(n^2) in the | |
73 // pick-next-block code). | |
74 // | |
605 | 75 // The relevant data is kept in a struct of arrays (it could just as well be |
0 | 76 // an array of structs, but the struct-of-arrays is generally a little more |
77 // efficient). The arrays are indexed by register number (including | |
78 // stack-slots as registers) and so is bounded by 200 to 300 elements in | |
79 // practice. One array will map to a reaching def Node (or NULL for | |
80 // conflict/dead). The other array will map to a callee-saved register or | |
81 // OptoReg::Bad for not-callee-saved. | |
82 | |
83 | |
84 //------------------------------OopFlow---------------------------------------- | |
85 // Structure to pass around | |
86 struct OopFlow : public ResourceObj { | |
87 short *_callees; // Array mapping register to callee-saved | |
88 Node **_defs; // array mapping register to reaching def | |
89 // or NULL if dead/conflict | |
90 // OopFlow structs, when not being actively modified, describe the _end_ of | |
91 // this block. | |
92 Block *_b; // Block for this struct | |
93 OopFlow *_next; // Next free OopFlow | |
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94 // or NULL if dead/conflict |
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95 Compile* C; |
0 | 96 |
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97 OopFlow( short *callees, Node **defs, Compile* c ) : _callees(callees), _defs(defs), |
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98 _b(NULL), _next(NULL), C(c) { } |
0 | 99 |
100 // Given reaching-defs for this block start, compute it for this block end | |
101 void compute_reach( PhaseRegAlloc *regalloc, int max_reg, Dict *safehash ); | |
102 | |
103 // Merge these two OopFlows into the 'this' pointer. | |
104 void merge( OopFlow *flow, int max_reg ); | |
105 | |
106 // Copy a 'flow' over an existing flow | |
107 void clone( OopFlow *flow, int max_size); | |
108 | |
109 // Make a new OopFlow from scratch | |
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110 static OopFlow *make( Arena *A, int max_size, Compile* C ); |
0 | 111 |
112 // Build an oopmap from the current flow info | |
113 OopMap *build_oop_map( Node *n, int max_reg, PhaseRegAlloc *regalloc, int* live ); | |
114 }; | |
115 | |
116 //------------------------------compute_reach---------------------------------- | |
117 // Given reaching-defs for this block start, compute it for this block end | |
118 void OopFlow::compute_reach( PhaseRegAlloc *regalloc, int max_reg, Dict *safehash ) { | |
119 | |
120 for( uint i=0; i<_b->_nodes.size(); i++ ) { | |
121 Node *n = _b->_nodes[i]; | |
122 | |
123 if( n->jvms() ) { // Build an OopMap here? | |
124 JVMState *jvms = n->jvms(); | |
125 // no map needed for leaf calls | |
126 if( n->is_MachSafePoint() && !n->is_MachCallLeaf() ) { | |
127 int *live = (int*) (*safehash)[n]; | |
128 assert( live, "must find live" ); | |
129 n->as_MachSafePoint()->set_oop_map( build_oop_map(n,max_reg,regalloc, live) ); | |
130 } | |
131 } | |
132 | |
133 // Assign new reaching def's. | |
134 // Note that I padded the _defs and _callees arrays so it's legal | |
135 // to index at _defs[OptoReg::Bad]. | |
136 OptoReg::Name first = regalloc->get_reg_first(n); | |
137 OptoReg::Name second = regalloc->get_reg_second(n); | |
138 _defs[first] = n; | |
139 _defs[second] = n; | |
140 | |
141 // Pass callee-save info around copies | |
142 int idx = n->is_Copy(); | |
143 if( idx ) { // Copies move callee-save info | |
144 OptoReg::Name old_first = regalloc->get_reg_first(n->in(idx)); | |
145 OptoReg::Name old_second = regalloc->get_reg_second(n->in(idx)); | |
146 int tmp_first = _callees[old_first]; | |
147 int tmp_second = _callees[old_second]; | |
148 _callees[old_first] = OptoReg::Bad; // callee-save is moved, dead in old location | |
149 _callees[old_second] = OptoReg::Bad; | |
150 _callees[first] = tmp_first; | |
151 _callees[second] = tmp_second; | |
152 } else if( n->is_Phi() ) { // Phis do not mod callee-saves | |
153 assert( _callees[first] == _callees[regalloc->get_reg_first(n->in(1))], "" ); | |
154 assert( _callees[second] == _callees[regalloc->get_reg_second(n->in(1))], "" ); | |
155 assert( _callees[first] == _callees[regalloc->get_reg_first(n->in(n->req()-1))], "" ); | |
156 assert( _callees[second] == _callees[regalloc->get_reg_second(n->in(n->req()-1))], "" ); | |
157 } else { | |
158 _callees[first] = OptoReg::Bad; // No longer holding a callee-save value | |
159 _callees[second] = OptoReg::Bad; | |
160 | |
161 // Find base case for callee saves | |
162 if( n->is_Proj() && n->in(0)->is_Start() ) { | |
163 if( OptoReg::is_reg(first) && | |
164 regalloc->_matcher.is_save_on_entry(first) ) | |
165 _callees[first] = first; | |
166 if( OptoReg::is_reg(second) && | |
167 regalloc->_matcher.is_save_on_entry(second) ) | |
168 _callees[second] = second; | |
169 } | |
170 } | |
171 } | |
172 } | |
173 | |
174 //------------------------------merge------------------------------------------ | |
175 // Merge the given flow into the 'this' flow | |
176 void OopFlow::merge( OopFlow *flow, int max_reg ) { | |
177 assert( _b == NULL, "merging into a happy flow" ); | |
178 assert( flow->_b, "this flow is still alive" ); | |
179 assert( flow != this, "no self flow" ); | |
180 | |
181 // Do the merge. If there are any differences, drop to 'bottom' which | |
182 // is OptoReg::Bad or NULL depending. | |
183 for( int i=0; i<max_reg; i++ ) { | |
184 // Merge the callee-save's | |
185 if( _callees[i] != flow->_callees[i] ) | |
186 _callees[i] = OptoReg::Bad; | |
187 // Merge the reaching defs | |
188 if( _defs[i] != flow->_defs[i] ) | |
189 _defs[i] = NULL; | |
190 } | |
191 | |
192 } | |
193 | |
194 //------------------------------clone------------------------------------------ | |
195 void OopFlow::clone( OopFlow *flow, int max_size ) { | |
196 _b = flow->_b; | |
197 memcpy( _callees, flow->_callees, sizeof(short)*max_size); | |
198 memcpy( _defs , flow->_defs , sizeof(Node*)*max_size); | |
199 } | |
200 | |
201 //------------------------------make------------------------------------------- | |
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202 OopFlow *OopFlow::make( Arena *A, int max_size, Compile* C ) { |
0 | 203 short *callees = NEW_ARENA_ARRAY(A,short,max_size+1); |
204 Node **defs = NEW_ARENA_ARRAY(A,Node*,max_size+1); | |
205 debug_only( memset(defs,0,(max_size+1)*sizeof(Node*)) ); | |
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206 OopFlow *flow = new (A) OopFlow(callees+1, defs+1, C); |
0 | 207 assert( &flow->_callees[OptoReg::Bad] == callees, "Ok to index at OptoReg::Bad" ); |
208 assert( &flow->_defs [OptoReg::Bad] == defs , "Ok to index at OptoReg::Bad" ); | |
209 return flow; | |
210 } | |
211 | |
212 //------------------------------bit twiddlers---------------------------------- | |
213 static int get_live_bit( int *live, int reg ) { | |
214 return live[reg>>LogBitsPerInt] & (1<<(reg&(BitsPerInt-1))); } | |
215 static void set_live_bit( int *live, int reg ) { | |
216 live[reg>>LogBitsPerInt] |= (1<<(reg&(BitsPerInt-1))); } | |
217 static void clr_live_bit( int *live, int reg ) { | |
218 live[reg>>LogBitsPerInt] &= ~(1<<(reg&(BitsPerInt-1))); } | |
219 | |
220 //------------------------------build_oop_map---------------------------------- | |
221 // Build an oopmap from the current flow info | |
222 OopMap *OopFlow::build_oop_map( Node *n, int max_reg, PhaseRegAlloc *regalloc, int* live ) { | |
223 int framesize = regalloc->_framesize; | |
224 int max_inarg_slot = OptoReg::reg2stack(regalloc->_matcher._new_SP); | |
225 debug_only( char *dup_check = NEW_RESOURCE_ARRAY(char,OptoReg::stack0()); | |
226 memset(dup_check,0,OptoReg::stack0()) ); | |
227 | |
228 OopMap *omap = new OopMap( framesize, max_inarg_slot ); | |
229 MachCallNode *mcall = n->is_MachCall() ? n->as_MachCall() : NULL; | |
230 JVMState* jvms = n->jvms(); | |
231 | |
232 // For all registers do... | |
233 for( int reg=0; reg<max_reg; reg++ ) { | |
234 if( get_live_bit(live,reg) == 0 ) | |
235 continue; // Ignore if not live | |
236 | |
237 // %%% C2 can use 2 OptoRegs when the physical register is only one 64bit | |
238 // register in that case we'll get an non-concrete register for the second | |
239 // half. We only need to tell the map the register once! | |
240 // | |
241 // However for the moment we disable this change and leave things as they | |
242 // were. | |
243 | |
244 VMReg r = OptoReg::as_VMReg(OptoReg::Name(reg), framesize, max_inarg_slot); | |
245 | |
246 if (false && r->is_reg() && !r->is_concrete()) { | |
247 continue; | |
248 } | |
249 | |
250 // See if dead (no reaching def). | |
251 Node *def = _defs[reg]; // Get reaching def | |
252 assert( def, "since live better have reaching def" ); | |
253 | |
254 // Classify the reaching def as oop, derived, callee-save, dead, or other | |
255 const Type *t = def->bottom_type(); | |
256 if( t->isa_oop_ptr() ) { // Oop or derived? | |
257 assert( !OptoReg::is_valid(_callees[reg]), "oop can't be callee save" ); | |
258 #ifdef _LP64 | |
259 // 64-bit pointers record oop-ishness on 2 aligned adjacent registers. | |
260 // Make sure both are record from the same reaching def, but do not | |
261 // put both into the oopmap. | |
262 if( (reg&1) == 1 ) { // High half of oop-pair? | |
263 assert( _defs[reg-1] == _defs[reg], "both halves from same reaching def" ); | |
264 continue; // Do not record high parts in oopmap | |
265 } | |
266 #endif | |
267 | |
268 // Check for a legal reg name in the oopMap and bailout if it is not. | |
269 if (!omap->legal_vm_reg_name(r)) { | |
270 regalloc->C->record_method_not_compilable("illegal oopMap register name"); | |
271 continue; | |
272 } | |
273 if( t->is_ptr()->_offset == 0 ) { // Not derived? | |
274 if( mcall ) { | |
275 // Outgoing argument GC mask responsibility belongs to the callee, | |
276 // not the caller. Inspect the inputs to the call, to see if | |
277 // this live-range is one of them. | |
278 uint cnt = mcall->tf()->domain()->cnt(); | |
279 uint j; | |
280 for( j = TypeFunc::Parms; j < cnt; j++) | |
281 if( mcall->in(j) == def ) | |
282 break; // reaching def is an argument oop | |
283 if( j < cnt ) // arg oops dont go in GC map | |
284 continue; // Continue on to the next register | |
285 } | |
286 omap->set_oop(r); | |
287 } else { // Else it's derived. | |
288 // Find the base of the derived value. | |
289 uint i; | |
290 // Fast, common case, scan | |
291 for( i = jvms->oopoff(); i < n->req(); i+=2 ) | |
292 if( n->in(i) == def ) break; // Common case | |
293 if( i == n->req() ) { // Missed, try a more generous scan | |
294 // Scan again, but this time peek through copies | |
295 for( i = jvms->oopoff(); i < n->req(); i+=2 ) { | |
296 Node *m = n->in(i); // Get initial derived value | |
297 while( 1 ) { | |
298 Node *d = def; // Get initial reaching def | |
299 while( 1 ) { // Follow copies of reaching def to end | |
300 if( m == d ) goto found; // breaks 3 loops | |
301 int idx = d->is_Copy(); | |
302 if( !idx ) break; | |
303 d = d->in(idx); // Link through copy | |
304 } | |
305 int idx = m->is_Copy(); | |
306 if( !idx ) break; | |
307 m = m->in(idx); | |
308 } | |
309 } | |
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310 guarantee( 0, "must find derived/base pair" ); |
0 | 311 } |
312 found: ; | |
313 Node *base = n->in(i+1); // Base is other half of pair | |
314 int breg = regalloc->get_reg_first(base); | |
315 VMReg b = OptoReg::as_VMReg(OptoReg::Name(breg), framesize, max_inarg_slot); | |
316 | |
317 // I record liveness at safepoints BEFORE I make the inputs | |
318 // live. This is because argument oops are NOT live at a | |
319 // safepoint (or at least they cannot appear in the oopmap). | |
320 // Thus bases of base/derived pairs might not be in the | |
321 // liveness data but they need to appear in the oopmap. | |
322 if( get_live_bit(live,breg) == 0 ) {// Not live? | |
323 // Flag it, so next derived pointer won't re-insert into oopmap | |
324 set_live_bit(live,breg); | |
325 // Already missed our turn? | |
326 if( breg < reg ) { | |
327 if (b->is_stack() || b->is_concrete() || true ) { | |
328 omap->set_oop( b); | |
329 } | |
330 } | |
331 } | |
332 if (b->is_stack() || b->is_concrete() || true ) { | |
333 omap->set_derived_oop( r, b); | |
334 } | |
335 } | |
336 | |
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337 } else if( t->isa_narrowoop() ) { |
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338 assert( !OptoReg::is_valid(_callees[reg]), "oop can't be callee save" ); |
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339 // Check for a legal reg name in the oopMap and bailout if it is not. |
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340 if (!omap->legal_vm_reg_name(r)) { |
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341 regalloc->C->record_method_not_compilable("illegal oopMap register name"); |
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342 continue; |
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343 } |
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344 if( mcall ) { |
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345 // Outgoing argument GC mask responsibility belongs to the callee, |
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346 // not the caller. Inspect the inputs to the call, to see if |
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347 // this live-range is one of them. |
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348 uint cnt = mcall->tf()->domain()->cnt(); |
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349 uint j; |
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350 for( j = TypeFunc::Parms; j < cnt; j++) |
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351 if( mcall->in(j) == def ) |
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352 break; // reaching def is an argument oop |
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353 if( j < cnt ) // arg oops dont go in GC map |
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354 continue; // Continue on to the next register |
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355 } |
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356 omap->set_narrowoop(r); |
0 | 357 } else if( OptoReg::is_valid(_callees[reg])) { // callee-save? |
358 // It's a callee-save value | |
359 assert( dup_check[_callees[reg]]==0, "trying to callee save same reg twice" ); | |
360 debug_only( dup_check[_callees[reg]]=1; ) | |
361 VMReg callee = OptoReg::as_VMReg(OptoReg::Name(_callees[reg])); | |
362 if ( callee->is_concrete() || true ) { | |
363 omap->set_callee_saved( r, callee); | |
364 } | |
365 | |
366 } else { | |
367 // Other - some reaching non-oop value | |
368 omap->set_value( r); | |
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369 #ifdef ASSERT |
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370 if( t->isa_rawptr() && C->cfg()->_raw_oops.member(def) ) { |
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371 def->dump(); |
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372 n->dump(); |
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373 assert(false, "there should be a oop in OopMap instead of a live raw oop at safepoint"); |
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374 } |
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375 #endif |
0 | 376 } |
377 | |
378 } | |
379 | |
380 #ifdef ASSERT | |
381 /* Nice, Intel-only assert | |
382 int cnt_callee_saves=0; | |
383 int reg2 = 0; | |
384 while (OptoReg::is_reg(reg2)) { | |
385 if( dup_check[reg2] != 0) cnt_callee_saves++; | |
386 assert( cnt_callee_saves==3 || cnt_callee_saves==5, "missed some callee-save" ); | |
387 reg2++; | |
388 } | |
389 */ | |
390 #endif | |
391 | |
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392 #ifdef ASSERT |
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393 for( OopMapStream oms1(omap, OopMapValue::derived_oop_value); !oms1.is_done(); oms1.next()) { |
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394 OopMapValue omv1 = oms1.current(); |
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395 bool found = false; |
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396 for( OopMapStream oms2(omap,OopMapValue::oop_value); !oms2.is_done(); oms2.next()) { |
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397 if( omv1.content_reg() == oms2.current().reg() ) { |
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398 found = true; |
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399 break; |
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400 } |
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401 } |
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402 assert( found, "derived with no base in oopmap" ); |
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403 } |
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404 #endif |
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405 |
0 | 406 return omap; |
407 } | |
408 | |
409 //------------------------------do_liveness------------------------------------ | |
410 // Compute backwards liveness on registers | |
411 static void do_liveness( PhaseRegAlloc *regalloc, PhaseCFG *cfg, Block_List *worklist, int max_reg_ints, Arena *A, Dict *safehash ) { | |
412 int *live = NEW_ARENA_ARRAY(A, int, (cfg->_num_blocks+1) * max_reg_ints); | |
413 int *tmp_live = &live[cfg->_num_blocks * max_reg_ints]; | |
414 Node *root = cfg->C->root(); | |
415 // On CISC platforms, get the node representing the stack pointer that regalloc | |
416 // used for spills | |
417 Node *fp = NodeSentinel; | |
418 if (UseCISCSpill && root->req() > 1) { | |
419 fp = root->in(1)->in(TypeFunc::FramePtr); | |
420 } | |
421 memset( live, 0, cfg->_num_blocks * (max_reg_ints<<LogBytesPerInt) ); | |
422 // Push preds onto worklist | |
423 for( uint i=1; i<root->req(); i++ ) | |
424 worklist->push(cfg->_bbs[root->in(i)->_idx]); | |
425 | |
426 // ZKM.jar includes tiny infinite loops which are unreached from below. | |
427 // If we missed any blocks, we'll retry here after pushing all missed | |
428 // blocks on the worklist. Normally this outer loop never trips more | |
429 // than once. | |
430 while( 1 ) { | |
431 | |
432 while( worklist->size() ) { // Standard worklist algorithm | |
433 Block *b = worklist->rpop(); | |
434 | |
435 // Copy first successor into my tmp_live space | |
436 int s0num = b->_succs[0]->_pre_order; | |
437 int *t = &live[s0num*max_reg_ints]; | |
438 for( int i=0; i<max_reg_ints; i++ ) | |
439 tmp_live[i] = t[i]; | |
440 | |
441 // OR in the remaining live registers | |
442 for( uint j=1; j<b->_num_succs; j++ ) { | |
443 uint sjnum = b->_succs[j]->_pre_order; | |
444 int *t = &live[sjnum*max_reg_ints]; | |
445 for( int i=0; i<max_reg_ints; i++ ) | |
446 tmp_live[i] |= t[i]; | |
447 } | |
448 | |
449 // Now walk tmp_live up the block backwards, computing live | |
450 for( int k=b->_nodes.size()-1; k>=0; k-- ) { | |
451 Node *n = b->_nodes[k]; | |
452 // KILL def'd bits | |
453 int first = regalloc->get_reg_first(n); | |
454 int second = regalloc->get_reg_second(n); | |
455 if( OptoReg::is_valid(first) ) clr_live_bit(tmp_live,first); | |
456 if( OptoReg::is_valid(second) ) clr_live_bit(tmp_live,second); | |
457 | |
458 MachNode *m = n->is_Mach() ? n->as_Mach() : NULL; | |
459 | |
460 // Check if m is potentially a CISC alternate instruction (i.e, possibly | |
461 // synthesized by RegAlloc from a conventional instruction and a | |
462 // spilled input) | |
463 bool is_cisc_alternate = false; | |
464 if (UseCISCSpill && m) { | |
465 is_cisc_alternate = m->is_cisc_alternate(); | |
466 } | |
467 | |
468 // GEN use'd bits | |
469 for( uint l=1; l<n->req(); l++ ) { | |
470 Node *def = n->in(l); | |
471 assert(def != 0, "input edge required"); | |
472 int first = regalloc->get_reg_first(def); | |
473 int second = regalloc->get_reg_second(def); | |
474 if( OptoReg::is_valid(first) ) set_live_bit(tmp_live,first); | |
475 if( OptoReg::is_valid(second) ) set_live_bit(tmp_live,second); | |
476 // If we use the stack pointer in a cisc-alternative instruction, | |
477 // check for use as a memory operand. Then reconstruct the RegName | |
478 // for this stack location, and set the appropriate bit in the | |
479 // live vector 4987749. | |
480 if (is_cisc_alternate && def == fp) { | |
481 const TypePtr *adr_type = NULL; | |
482 intptr_t offset; | |
483 const Node* base = m->get_base_and_disp(offset, adr_type); | |
484 if (base == NodeSentinel) { | |
485 // Machnode has multiple memory inputs. We are unable to reason | |
486 // with these, but are presuming (with trepidation) that not any of | |
487 // them are oops. This can be fixed by making get_base_and_disp() | |
488 // look at a specific input instead of all inputs. | |
489 assert(!def->bottom_type()->isa_oop_ptr(), "expecting non-oop mem input"); | |
490 } else if (base != fp || offset == Type::OffsetBot) { | |
491 // Do nothing: the fp operand is either not from a memory use | |
492 // (base == NULL) OR the fp is used in a non-memory context | |
493 // (base is some other register) OR the offset is not constant, | |
494 // so it is not a stack slot. | |
495 } else { | |
496 assert(offset >= 0, "unexpected negative offset"); | |
497 offset -= (offset % jintSize); // count the whole word | |
498 int stack_reg = regalloc->offset2reg(offset); | |
499 if (OptoReg::is_stack(stack_reg)) { | |
500 set_live_bit(tmp_live, stack_reg); | |
501 } else { | |
502 assert(false, "stack_reg not on stack?"); | |
503 } | |
504 } | |
505 } | |
506 } | |
507 | |
508 if( n->jvms() ) { // Record liveness at safepoint | |
509 | |
510 // This placement of this stanza means inputs to calls are | |
511 // considered live at the callsite's OopMap. Argument oops are | |
512 // hence live, but NOT included in the oopmap. See cutout in | |
513 // build_oop_map. Debug oops are live (and in OopMap). | |
514 int *n_live = NEW_ARENA_ARRAY(A, int, max_reg_ints); | |
515 for( int l=0; l<max_reg_ints; l++ ) | |
516 n_live[l] = tmp_live[l]; | |
517 safehash->Insert(n,n_live); | |
518 } | |
519 | |
520 } | |
521 | |
522 // Now at block top, see if we have any changes. If so, propagate | |
523 // to prior blocks. | |
524 int *old_live = &live[b->_pre_order*max_reg_ints]; | |
525 int l; | |
526 for( l=0; l<max_reg_ints; l++ ) | |
527 if( tmp_live[l] != old_live[l] ) | |
528 break; | |
529 if( l<max_reg_ints ) { // Change! | |
530 // Copy in new value | |
531 for( l=0; l<max_reg_ints; l++ ) | |
532 old_live[l] = tmp_live[l]; | |
533 // Push preds onto worklist | |
534 for( l=1; l<(int)b->num_preds(); l++ ) | |
535 worklist->push(cfg->_bbs[b->pred(l)->_idx]); | |
536 } | |
537 } | |
538 | |
539 // Scan for any missing safepoints. Happens to infinite loops | |
540 // ala ZKM.jar | |
541 uint i; | |
542 for( i=1; i<cfg->_num_blocks; i++ ) { | |
543 Block *b = cfg->_blocks[i]; | |
544 uint j; | |
545 for( j=1; j<b->_nodes.size(); j++ ) | |
546 if( b->_nodes[j]->jvms() && | |
547 (*safehash)[b->_nodes[j]] == NULL ) | |
548 break; | |
549 if( j<b->_nodes.size() ) break; | |
550 } | |
551 if( i == cfg->_num_blocks ) | |
552 break; // Got 'em all | |
553 #ifndef PRODUCT | |
554 if( PrintOpto && Verbose ) | |
555 tty->print_cr("retripping live calc"); | |
556 #endif | |
557 // Force the issue (expensively): recheck everybody | |
558 for( i=1; i<cfg->_num_blocks; i++ ) | |
559 worklist->push(cfg->_blocks[i]); | |
560 } | |
561 | |
562 } | |
563 | |
564 //------------------------------BuildOopMaps----------------------------------- | |
565 // Collect GC mask info - where are all the OOPs? | |
566 void Compile::BuildOopMaps() { | |
567 NOT_PRODUCT( TracePhase t3("bldOopMaps", &_t_buildOopMaps, TimeCompiler); ) | |
568 // Can't resource-mark because I need to leave all those OopMaps around, | |
569 // or else I need to resource-mark some arena other than the default. | |
570 // ResourceMark rm; // Reclaim all OopFlows when done | |
571 int max_reg = _regalloc->_max_reg; // Current array extent | |
572 | |
573 Arena *A = Thread::current()->resource_area(); | |
574 Block_List worklist; // Worklist of pending blocks | |
575 | |
576 int max_reg_ints = round_to(max_reg, BitsPerInt)>>LogBitsPerInt; | |
577 Dict *safehash = NULL; // Used for assert only | |
578 // Compute a backwards liveness per register. Needs a bitarray of | |
579 // #blocks x (#registers, rounded up to ints) | |
580 safehash = new Dict(cmpkey,hashkey,A); | |
581 do_liveness( _regalloc, _cfg, &worklist, max_reg_ints, A, safehash ); | |
582 OopFlow *free_list = NULL; // Free, unused | |
583 | |
584 // Array mapping blocks to completed oopflows | |
585 OopFlow **flows = NEW_ARENA_ARRAY(A, OopFlow*, _cfg->_num_blocks); | |
586 memset( flows, 0, _cfg->_num_blocks*sizeof(OopFlow*) ); | |
587 | |
588 | |
589 // Do the first block 'by hand' to prime the worklist | |
590 Block *entry = _cfg->_blocks[1]; | |
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591 OopFlow *rootflow = OopFlow::make(A,max_reg,this); |
0 | 592 // Initialize to 'bottom' (not 'top') |
593 memset( rootflow->_callees, OptoReg::Bad, max_reg*sizeof(short) ); | |
594 memset( rootflow->_defs , 0, max_reg*sizeof(Node*) ); | |
595 flows[entry->_pre_order] = rootflow; | |
596 | |
597 // Do the first block 'by hand' to prime the worklist | |
598 rootflow->_b = entry; | |
599 rootflow->compute_reach( _regalloc, max_reg, safehash ); | |
600 for( uint i=0; i<entry->_num_succs; i++ ) | |
601 worklist.push(entry->_succs[i]); | |
602 | |
603 // Now worklist contains blocks which have some, but perhaps not all, | |
604 // predecessors visited. | |
605 while( worklist.size() ) { | |
606 // Scan for a block with all predecessors visited, or any randoms slob | |
607 // otherwise. All-preds-visited order allows me to recycle OopFlow | |
608 // structures rapidly and cut down on the memory footprint. | |
609 // Note: not all predecessors might be visited yet (must happen for | |
610 // irreducible loops). This is OK, since every live value must have the | |
611 // SAME reaching def for the block, so any reaching def is OK. | |
612 uint i; | |
613 | |
614 Block *b = worklist.pop(); | |
615 // Ignore root block | |
616 if( b == _cfg->_broot ) continue; | |
617 // Block is already done? Happens if block has several predecessors, | |
618 // he can get on the worklist more than once. | |
619 if( flows[b->_pre_order] ) continue; | |
620 | |
621 // If this block has a visited predecessor AND that predecessor has this | |
622 // last block as his only undone child, we can move the OopFlow from the | |
623 // pred to this block. Otherwise we have to grab a new OopFlow. | |
624 OopFlow *flow = NULL; // Flag for finding optimized flow | |
625 Block *pred = (Block*)0xdeadbeef; | |
626 uint j; | |
627 // Scan this block's preds to find a done predecessor | |
628 for( j=1; j<b->num_preds(); j++ ) { | |
629 Block *p = _cfg->_bbs[b->pred(j)->_idx]; | |
630 OopFlow *p_flow = flows[p->_pre_order]; | |
631 if( p_flow ) { // Predecessor is done | |
632 assert( p_flow->_b == p, "cross check" ); | |
633 pred = p; // Record some predecessor | |
634 // If all successors of p are done except for 'b', then we can carry | |
635 // p_flow forward to 'b' without copying, otherwise we have to draw | |
636 // from the free_list and clone data. | |
637 uint k; | |
638 for( k=0; k<p->_num_succs; k++ ) | |
639 if( !flows[p->_succs[k]->_pre_order] && | |
640 p->_succs[k] != b ) | |
641 break; | |
642 | |
643 // Either carry-forward the now-unused OopFlow for b's use | |
644 // or draw a new one from the free list | |
645 if( k==p->_num_succs ) { | |
646 flow = p_flow; | |
647 break; // Found an ideal pred, use him | |
648 } | |
649 } | |
650 } | |
651 | |
652 if( flow ) { | |
653 // We have an OopFlow that's the last-use of a predecessor. | |
654 // Carry it forward. | |
655 } else { // Draw a new OopFlow from the freelist | |
656 if( !free_list ) | |
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657 free_list = OopFlow::make(A,max_reg,C); |
0 | 658 flow = free_list; |
659 assert( flow->_b == NULL, "oopFlow is not free" ); | |
660 free_list = flow->_next; | |
661 flow->_next = NULL; | |
662 | |
663 // Copy/clone over the data | |
664 flow->clone(flows[pred->_pre_order], max_reg); | |
665 } | |
666 | |
667 // Mark flow for block. Blocks can only be flowed over once, | |
668 // because after the first time they are guarded from entering | |
669 // this code again. | |
670 assert( flow->_b == pred, "have some prior flow" ); | |
671 flow->_b = NULL; | |
672 | |
673 // Now push flow forward | |
674 flows[b->_pre_order] = flow;// Mark flow for this block | |
675 flow->_b = b; | |
676 flow->compute_reach( _regalloc, max_reg, safehash ); | |
677 | |
678 // Now push children onto worklist | |
679 for( i=0; i<b->_num_succs; i++ ) | |
680 worklist.push(b->_succs[i]); | |
681 | |
682 } | |
683 } |