Mercurial > hg > graal-compiler
annotate src/share/vm/opto/buildOopMap.cpp @ 1815:5867d89c129b
6982537: Crash in Node*step_through_mergemem
Reviewed-by: kvn
author | never |
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date | Wed, 22 Sep 2010 13:01:12 -0700 |
parents | c18cbe5936b8 |
children | f95d63e2154a |
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0 | 1 /* |
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2 * Copyright (c) 2002, 2009, 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 | |
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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). | |
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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 | |
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 } |