Mercurial > hg > truffle
annotate src/share/vm/c1/c1_IR.cpp @ 21046:d35d2ac04970
weakened check used by an assertion in the FrameStateAssignmentPhase
author | Doug Simon <doug.simon@oracle.com> |
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date | Mon, 20 Apr 2015 19:07:49 +0200 |
parents | 52b4284cb496 |
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rev | line source |
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0 | 1 /* |
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2 * Copyright (c) 1999, 2013, 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 "c1/c1_Compilation.hpp" | |
27 #include "c1/c1_FrameMap.hpp" | |
28 #include "c1/c1_GraphBuilder.hpp" | |
29 #include "c1/c1_IR.hpp" | |
30 #include "c1/c1_InstructionPrinter.hpp" | |
31 #include "c1/c1_Optimizer.hpp" | |
32 #include "utilities/bitMap.inline.hpp" | |
0 | 33 |
34 | |
35 // Implementation of XHandlers | |
36 // | |
37 // Note: This code could eventually go away if we are | |
38 // just using the ciExceptionHandlerStream. | |
39 | |
40 XHandlers::XHandlers(ciMethod* method) : _list(method->exception_table_length()) { | |
41 ciExceptionHandlerStream s(method); | |
42 while (!s.is_done()) { | |
43 _list.append(new XHandler(s.handler())); | |
44 s.next(); | |
45 } | |
46 assert(s.count() == method->exception_table_length(), "exception table lengths inconsistent"); | |
47 } | |
48 | |
49 // deep copy of all XHandler contained in list | |
50 XHandlers::XHandlers(XHandlers* other) : | |
51 _list(other->length()) | |
52 { | |
53 for (int i = 0; i < other->length(); i++) { | |
54 _list.append(new XHandler(other->handler_at(i))); | |
55 } | |
56 } | |
57 | |
58 // Returns whether a particular exception type can be caught. Also | |
59 // returns true if klass is unloaded or any exception handler | |
60 // classes are unloaded. type_is_exact indicates whether the throw | |
61 // is known to be exactly that class or it might throw a subtype. | |
62 bool XHandlers::could_catch(ciInstanceKlass* klass, bool type_is_exact) const { | |
63 // the type is unknown so be conservative | |
64 if (!klass->is_loaded()) { | |
65 return true; | |
66 } | |
67 | |
68 for (int i = 0; i < length(); i++) { | |
69 XHandler* handler = handler_at(i); | |
70 if (handler->is_catch_all()) { | |
71 // catch of ANY | |
72 return true; | |
73 } | |
74 ciInstanceKlass* handler_klass = handler->catch_klass(); | |
75 // if it's unknown it might be catchable | |
76 if (!handler_klass->is_loaded()) { | |
77 return true; | |
78 } | |
79 // if the throw type is definitely a subtype of the catch type | |
80 // then it can be caught. | |
81 if (klass->is_subtype_of(handler_klass)) { | |
82 return true; | |
83 } | |
84 if (!type_is_exact) { | |
85 // If the type isn't exactly known then it can also be caught by | |
86 // catch statements where the inexact type is a subtype of the | |
87 // catch type. | |
88 // given: foo extends bar extends Exception | |
89 // throw bar can be caught by catch foo, catch bar, and catch | |
90 // Exception, however it can't be caught by any handlers without | |
91 // bar in its type hierarchy. | |
92 if (handler_klass->is_subtype_of(klass)) { | |
93 return true; | |
94 } | |
95 } | |
96 } | |
97 | |
98 return false; | |
99 } | |
100 | |
101 | |
102 bool XHandlers::equals(XHandlers* others) const { | |
103 if (others == NULL) return false; | |
104 if (length() != others->length()) return false; | |
105 | |
106 for (int i = 0; i < length(); i++) { | |
107 if (!handler_at(i)->equals(others->handler_at(i))) return false; | |
108 } | |
109 return true; | |
110 } | |
111 | |
112 bool XHandler::equals(XHandler* other) const { | |
113 assert(entry_pco() != -1 && other->entry_pco() != -1, "must have entry_pco"); | |
114 | |
115 if (entry_pco() != other->entry_pco()) return false; | |
116 if (scope_count() != other->scope_count()) return false; | |
117 if (_desc != other->_desc) return false; | |
118 | |
119 assert(entry_block() == other->entry_block(), "entry_block must be equal when entry_pco is equal"); | |
120 return true; | |
121 } | |
122 | |
123 | |
124 // Implementation of IRScope | |
125 BlockBegin* IRScope::build_graph(Compilation* compilation, int osr_bci) { | |
126 GraphBuilder gm(compilation, this); | |
127 NOT_PRODUCT(if (PrintValueNumbering && Verbose) gm.print_stats()); | |
128 if (compilation->bailed_out()) return NULL; | |
129 return gm.start(); | |
130 } | |
131 | |
132 | |
133 IRScope::IRScope(Compilation* compilation, IRScope* caller, int caller_bci, ciMethod* method, int osr_bci, bool create_graph) | |
134 : _callees(2) | |
135 , _compilation(compilation) | |
136 , _requires_phi_function(method->max_locals()) | |
137 { | |
138 _caller = caller; | |
139 _level = caller == NULL ? 0 : caller->level() + 1; | |
140 _method = method; | |
141 _xhandlers = new XHandlers(method); | |
142 _number_of_locks = 0; | |
143 _monitor_pairing_ok = method->has_balanced_monitors(); | |
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144 _wrote_final = false; |
0 | 145 _start = NULL; |
146 | |
147 if (osr_bci == -1) { | |
148 _requires_phi_function.clear(); | |
149 } else { | |
150 // selective creation of phi functions is not possibel in osr-methods | |
151 _requires_phi_function.set_range(0, method->max_locals()); | |
152 } | |
153 | |
154 assert(method->holder()->is_loaded() , "method holder must be loaded"); | |
155 | |
156 // build graph if monitor pairing is ok | |
157 if (create_graph && monitor_pairing_ok()) _start = build_graph(compilation, osr_bci); | |
158 } | |
159 | |
160 | |
161 int IRScope::max_stack() const { | |
162 int my_max = method()->max_stack(); | |
163 int callee_max = 0; | |
164 for (int i = 0; i < number_of_callees(); i++) { | |
165 callee_max = MAX2(callee_max, callee_no(i)->max_stack()); | |
166 } | |
167 return my_max + callee_max; | |
168 } | |
169 | |
170 | |
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171 bool IRScopeDebugInfo::should_reexecute() { |
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172 ciMethod* cur_method = scope()->method(); |
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173 int cur_bci = bci(); |
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174 if (cur_method != NULL && cur_bci != SynchronizationEntryBCI) { |
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175 Bytecodes::Code code = cur_method->java_code_at_bci(cur_bci); |
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176 return Interpreter::bytecode_should_reexecute(code); |
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177 } else |
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178 return false; |
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179 } |
0 | 180 |
181 | |
182 // Implementation of CodeEmitInfo | |
183 | |
184 // Stack must be NON-null | |
8860 | 185 CodeEmitInfo::CodeEmitInfo(ValueStack* stack, XHandlers* exception_handlers, bool deoptimize_on_exception) |
0 | 186 : _scope(stack->scope()) |
187 , _scope_debug_info(NULL) | |
188 , _oop_map(NULL) | |
189 , _stack(stack) | |
190 , _exception_handlers(exception_handlers) | |
8860 | 191 , _is_method_handle_invoke(false) |
192 , _deoptimize_on_exception(deoptimize_on_exception) { | |
0 | 193 assert(_stack != NULL, "must be non null"); |
194 } | |
195 | |
196 | |
1819 | 197 CodeEmitInfo::CodeEmitInfo(CodeEmitInfo* info, ValueStack* stack) |
0 | 198 : _scope(info->_scope) |
199 , _exception_handlers(NULL) | |
200 , _scope_debug_info(NULL) | |
1564 | 201 , _oop_map(NULL) |
1819 | 202 , _stack(stack == NULL ? info->_stack : stack) |
8860 | 203 , _is_method_handle_invoke(info->_is_method_handle_invoke) |
204 , _deoptimize_on_exception(info->_deoptimize_on_exception) { | |
0 | 205 |
206 // deep copy of exception handlers | |
207 if (info->_exception_handlers != NULL) { | |
208 _exception_handlers = new XHandlers(info->_exception_handlers); | |
209 } | |
210 } | |
211 | |
212 | |
1564 | 213 void CodeEmitInfo::record_debug_info(DebugInformationRecorder* recorder, int pc_offset) { |
0 | 214 // record the safepoint before recording the debug info for enclosing scopes |
215 recorder->add_safepoint(pc_offset, _oop_map->deep_copy()); | |
1564 | 216 _scope_debug_info->record_debug_info(recorder, pc_offset, true/*topmost*/, _is_method_handle_invoke); |
0 | 217 recorder->end_safepoint(pc_offset); |
218 } | |
219 | |
220 | |
221 void CodeEmitInfo::add_register_oop(LIR_Opr opr) { | |
222 assert(_oop_map != NULL, "oop map must already exist"); | |
223 assert(opr->is_single_cpu(), "should not call otherwise"); | |
224 | |
225 VMReg name = frame_map()->regname(opr); | |
226 _oop_map->set_oop(name); | |
227 } | |
228 | |
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229 // Mirror the stack size calculation in the deopt code |
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230 // How much stack space would we need at this point in the program in |
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231 // case of deoptimization? |
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232 int CodeEmitInfo::interpreter_frame_size() const { |
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233 ValueStack* state = _stack; |
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234 int size = 0; |
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235 int callee_parameters = 0; |
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236 int callee_locals = 0; |
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237 int extra_args = state->scope()->method()->max_stack() - state->stack_size(); |
0 | 238 |
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239 while (state != NULL) { |
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240 int locks = state->locks_size(); |
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241 int temps = state->stack_size(); |
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242 bool is_top_frame = (state == _stack); |
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243 ciMethod* method = state->scope()->method(); |
0 | 244 |
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245 int frame_size = BytesPerWord * Interpreter::size_activation(method->max_stack(), |
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246 temps + callee_parameters, |
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247 extra_args, |
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248 locks, |
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249 callee_parameters, |
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250 callee_locals, |
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251 is_top_frame); |
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252 size += frame_size; |
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253 |
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254 callee_parameters = method->size_of_parameters(); |
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255 callee_locals = method->max_locals(); |
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256 extra_args = 0; |
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257 state = state->caller_state(); |
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258 } |
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259 return size + Deoptimization::last_frame_adjust(0, callee_locals) * BytesPerWord; |
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260 } |
0 | 261 |
262 // Implementation of IR | |
263 | |
264 IR::IR(Compilation* compilation, ciMethod* method, int osr_bci) : | |
265 _locals_size(in_WordSize(-1)) | |
266 , _num_loops(0) { | |
267 // setup IR fields | |
268 _compilation = compilation; | |
269 _top_scope = new IRScope(compilation, NULL, -1, method, osr_bci, true); | |
270 _code = NULL; | |
271 } | |
272 | |
273 | |
8860 | 274 void IR::optimize_blocks() { |
0 | 275 Optimizer opt(this); |
1783 | 276 if (!compilation()->profile_branches()) { |
277 if (DoCEE) { | |
278 opt.eliminate_conditional_expressions(); | |
0 | 279 #ifndef PRODUCT |
1783 | 280 if (PrintCFG || PrintCFG1) { tty->print_cr("CFG after CEE"); print(true); } |
281 if (PrintIR || PrintIR1 ) { tty->print_cr("IR after CEE"); print(false); } | |
0 | 282 #endif |
1783 | 283 } |
284 if (EliminateBlocks) { | |
285 opt.eliminate_blocks(); | |
0 | 286 #ifndef PRODUCT |
1783 | 287 if (PrintCFG || PrintCFG1) { tty->print_cr("CFG after block elimination"); print(true); } |
288 if (PrintIR || PrintIR1 ) { tty->print_cr("IR after block elimination"); print(false); } | |
0 | 289 #endif |
1783 | 290 } |
0 | 291 } |
8860 | 292 } |
293 | |
294 void IR::eliminate_null_checks() { | |
295 Optimizer opt(this); | |
0 | 296 if (EliminateNullChecks) { |
297 opt.eliminate_null_checks(); | |
298 #ifndef PRODUCT | |
299 if (PrintCFG || PrintCFG1) { tty->print_cr("CFG after null check elimination"); print(true); } | |
300 if (PrintIR || PrintIR1 ) { tty->print_cr("IR after null check elimination"); print(false); } | |
301 #endif | |
302 } | |
303 } | |
304 | |
305 | |
306 static int sort_pairs(BlockPair** a, BlockPair** b) { | |
307 if ((*a)->from() == (*b)->from()) { | |
308 return (*a)->to()->block_id() - (*b)->to()->block_id(); | |
309 } else { | |
310 return (*a)->from()->block_id() - (*b)->from()->block_id(); | |
311 } | |
312 } | |
313 | |
314 | |
315 class CriticalEdgeFinder: public BlockClosure { | |
316 BlockPairList blocks; | |
317 IR* _ir; | |
318 | |
319 public: | |
320 CriticalEdgeFinder(IR* ir): _ir(ir) {} | |
321 void block_do(BlockBegin* bb) { | |
322 BlockEnd* be = bb->end(); | |
323 int nos = be->number_of_sux(); | |
324 if (nos >= 2) { | |
325 for (int i = 0; i < nos; i++) { | |
326 BlockBegin* sux = be->sux_at(i); | |
327 if (sux->number_of_preds() >= 2) { | |
328 blocks.append(new BlockPair(bb, sux)); | |
329 } | |
330 } | |
331 } | |
332 } | |
333 | |
334 void split_edges() { | |
335 BlockPair* last_pair = NULL; | |
336 blocks.sort(sort_pairs); | |
337 for (int i = 0; i < blocks.length(); i++) { | |
338 BlockPair* pair = blocks.at(i); | |
339 if (last_pair != NULL && pair->is_same(last_pair)) continue; | |
340 BlockBegin* from = pair->from(); | |
341 BlockBegin* to = pair->to(); | |
342 BlockBegin* split = from->insert_block_between(to); | |
343 #ifndef PRODUCT | |
344 if ((PrintIR || PrintIR1) && Verbose) { | |
345 tty->print_cr("Split critical edge B%d -> B%d (new block B%d)", | |
346 from->block_id(), to->block_id(), split->block_id()); | |
347 } | |
348 #endif | |
349 last_pair = pair; | |
350 } | |
351 } | |
352 }; | |
353 | |
354 void IR::split_critical_edges() { | |
355 CriticalEdgeFinder cef(this); | |
356 | |
357 iterate_preorder(&cef); | |
358 cef.split_edges(); | |
359 } | |
360 | |
361 | |
1584 | 362 class UseCountComputer: public ValueVisitor, BlockClosure { |
0 | 363 private: |
1584 | 364 void visit(Value* n) { |
0 | 365 // Local instructions and Phis for expression stack values at the |
366 // start of basic blocks are not added to the instruction list | |
1899 | 367 if (!(*n)->is_linked() && (*n)->can_be_linked()) { |
0 | 368 assert(false, "a node was not appended to the graph"); |
1584 | 369 Compilation::current()->bailout("a node was not appended to the graph"); |
0 | 370 } |
371 // use n's input if not visited before | |
372 if (!(*n)->is_pinned() && !(*n)->has_uses()) { | |
373 // note: a) if the instruction is pinned, it will be handled by compute_use_count | |
374 // b) if the instruction has uses, it was touched before | |
375 // => in both cases we don't need to update n's values | |
376 uses_do(n); | |
377 } | |
378 // use n | |
379 (*n)->_use_count++; | |
380 } | |
381 | |
1584 | 382 Values* worklist; |
383 int depth; | |
0 | 384 enum { |
385 max_recurse_depth = 20 | |
386 }; | |
387 | |
1584 | 388 void uses_do(Value* n) { |
0 | 389 depth++; |
390 if (depth > max_recurse_depth) { | |
391 // don't allow the traversal to recurse too deeply | |
392 worklist->push(*n); | |
393 } else { | |
1584 | 394 (*n)->input_values_do(this); |
0 | 395 // special handling for some instructions |
396 if ((*n)->as_BlockEnd() != NULL) { | |
397 // note on BlockEnd: | |
398 // must 'use' the stack only if the method doesn't | |
399 // terminate, however, in those cases stack is empty | |
1584 | 400 (*n)->state_values_do(this); |
0 | 401 } |
402 } | |
403 depth--; | |
404 } | |
405 | |
1584 | 406 void block_do(BlockBegin* b) { |
0 | 407 depth = 0; |
408 // process all pinned nodes as the roots of expression trees | |
409 for (Instruction* n = b; n != NULL; n = n->next()) { | |
410 if (n->is_pinned()) uses_do(&n); | |
411 } | |
412 assert(depth == 0, "should have counted back down"); | |
413 | |
414 // now process any unpinned nodes which recursed too deeply | |
415 while (worklist->length() > 0) { | |
416 Value t = worklist->pop(); | |
417 if (!t->is_pinned()) { | |
418 // compute the use count | |
419 uses_do(&t); | |
420 | |
421 // pin the instruction so that LIRGenerator doesn't recurse | |
422 // too deeply during it's evaluation. | |
423 t->pin(); | |
424 } | |
425 } | |
426 assert(depth == 0, "should have counted back down"); | |
427 } | |
428 | |
1584 | 429 UseCountComputer() { |
430 worklist = new Values(); | |
431 depth = 0; | |
432 } | |
433 | |
0 | 434 public: |
435 static void compute(BlockList* blocks) { | |
1584 | 436 UseCountComputer ucc; |
437 blocks->iterate_backward(&ucc); | |
0 | 438 } |
439 }; | |
440 | |
441 | |
442 // helper macro for short definition of trace-output inside code | |
443 #ifndef PRODUCT | |
444 #define TRACE_LINEAR_SCAN(level, code) \ | |
445 if (TraceLinearScanLevel >= level) { \ | |
446 code; \ | |
447 } | |
448 #else | |
449 #define TRACE_LINEAR_SCAN(level, code) | |
450 #endif | |
451 | |
452 class ComputeLinearScanOrder : public StackObj { | |
453 private: | |
454 int _max_block_id; // the highest block_id of a block | |
455 int _num_blocks; // total number of blocks (smaller than _max_block_id) | |
456 int _num_loops; // total number of loops | |
457 bool _iterative_dominators;// method requires iterative computation of dominatiors | |
458 | |
459 BlockList* _linear_scan_order; // the resulting list of blocks in correct order | |
460 | |
461 BitMap _visited_blocks; // used for recursive processing of blocks | |
462 BitMap _active_blocks; // used for recursive processing of blocks | |
463 BitMap _dominator_blocks; // temproary BitMap used for computation of dominator | |
464 intArray _forward_branches; // number of incoming forward branches for each block | |
465 BlockList _loop_end_blocks; // list of all loop end blocks collected during count_edges | |
466 BitMap2D _loop_map; // two-dimensional bit set: a bit is set if a block is contained in a loop | |
467 BlockList _work_list; // temporary list (used in mark_loops and compute_order) | |
8860 | 468 BlockList _loop_headers; |
0 | 469 |
1783 | 470 Compilation* _compilation; |
471 | |
0 | 472 // accessors for _visited_blocks and _active_blocks |
473 void init_visited() { _active_blocks.clear(); _visited_blocks.clear(); } | |
474 bool is_visited(BlockBegin* b) const { return _visited_blocks.at(b->block_id()); } | |
475 bool is_active(BlockBegin* b) const { return _active_blocks.at(b->block_id()); } | |
476 void set_visited(BlockBegin* b) { assert(!is_visited(b), "already set"); _visited_blocks.set_bit(b->block_id()); } | |
477 void set_active(BlockBegin* b) { assert(!is_active(b), "already set"); _active_blocks.set_bit(b->block_id()); } | |
478 void clear_active(BlockBegin* b) { assert(is_active(b), "not already"); _active_blocks.clear_bit(b->block_id()); } | |
479 | |
480 // accessors for _forward_branches | |
481 void inc_forward_branches(BlockBegin* b) { _forward_branches.at_put(b->block_id(), _forward_branches.at(b->block_id()) + 1); } | |
482 int dec_forward_branches(BlockBegin* b) { _forward_branches.at_put(b->block_id(), _forward_branches.at(b->block_id()) - 1); return _forward_branches.at(b->block_id()); } | |
483 | |
484 // accessors for _loop_map | |
485 bool is_block_in_loop (int loop_idx, BlockBegin* b) const { return _loop_map.at(loop_idx, b->block_id()); } | |
486 void set_block_in_loop (int loop_idx, BlockBegin* b) { _loop_map.set_bit(loop_idx, b->block_id()); } | |
487 void clear_block_in_loop(int loop_idx, int block_id) { _loop_map.clear_bit(loop_idx, block_id); } | |
488 | |
489 // count edges between blocks | |
490 void count_edges(BlockBegin* cur, BlockBegin* parent); | |
491 | |
492 // loop detection | |
493 void mark_loops(); | |
494 void clear_non_natural_loops(BlockBegin* start_block); | |
495 void assign_loop_depth(BlockBegin* start_block); | |
496 | |
497 // computation of final block order | |
498 BlockBegin* common_dominator(BlockBegin* a, BlockBegin* b); | |
499 void compute_dominator(BlockBegin* cur, BlockBegin* parent); | |
500 int compute_weight(BlockBegin* cur); | |
501 bool ready_for_processing(BlockBegin* cur); | |
502 void sort_into_work_list(BlockBegin* b); | |
503 void append_block(BlockBegin* cur); | |
504 void compute_order(BlockBegin* start_block); | |
505 | |
506 // fixup of dominators for non-natural loops | |
507 bool compute_dominators_iter(); | |
508 void compute_dominators(); | |
509 | |
510 // debug functions | |
511 NOT_PRODUCT(void print_blocks();) | |
512 DEBUG_ONLY(void verify();) | |
513 | |
1783 | 514 Compilation* compilation() const { return _compilation; } |
0 | 515 public: |
1783 | 516 ComputeLinearScanOrder(Compilation* c, BlockBegin* start_block); |
0 | 517 |
518 // accessors for final result | |
519 BlockList* linear_scan_order() const { return _linear_scan_order; } | |
520 int num_loops() const { return _num_loops; } | |
521 }; | |
522 | |
523 | |
1783 | 524 ComputeLinearScanOrder::ComputeLinearScanOrder(Compilation* c, BlockBegin* start_block) : |
0 | 525 _max_block_id(BlockBegin::number_of_blocks()), |
526 _num_blocks(0), | |
527 _num_loops(0), | |
528 _iterative_dominators(false), | |
529 _visited_blocks(_max_block_id), | |
530 _active_blocks(_max_block_id), | |
531 _dominator_blocks(_max_block_id), | |
532 _forward_branches(_max_block_id, 0), | |
533 _loop_end_blocks(8), | |
534 _work_list(8), | |
535 _linear_scan_order(NULL), // initialized later with correct size | |
1783 | 536 _loop_map(0, 0), // initialized later with correct size |
537 _compilation(c) | |
0 | 538 { |
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539 TRACE_LINEAR_SCAN(2, tty->print_cr("***** computing linear-scan block order")); |
0 | 540 |
541 init_visited(); | |
542 count_edges(start_block, NULL); | |
543 | |
1783 | 544 if (compilation()->is_profiling()) { |
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545 ciMethod *method = compilation()->method(); |
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546 if (!method->is_accessor()) { |
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547 ciMethodData* md = method->method_data_or_null(); |
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548 assert(md != NULL, "Sanity"); |
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549 md->set_compilation_stats(_num_loops, _num_blocks); |
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550 } |
1783 | 551 } |
552 | |
0 | 553 if (_num_loops > 0) { |
554 mark_loops(); | |
555 clear_non_natural_loops(start_block); | |
556 assign_loop_depth(start_block); | |
557 } | |
558 | |
559 compute_order(start_block); | |
560 compute_dominators(); | |
561 | |
562 NOT_PRODUCT(print_blocks()); | |
563 DEBUG_ONLY(verify()); | |
564 } | |
565 | |
566 | |
567 // Traverse the CFG: | |
568 // * count total number of blocks | |
569 // * count all incoming edges and backward incoming edges | |
570 // * number loop header blocks | |
571 // * create a list with all loop end blocks | |
572 void ComputeLinearScanOrder::count_edges(BlockBegin* cur, BlockBegin* parent) { | |
573 TRACE_LINEAR_SCAN(3, tty->print_cr("Enter count_edges for block B%d coming from B%d", cur->block_id(), parent != NULL ? parent->block_id() : -1)); | |
574 assert(cur->dominator() == NULL, "dominator already initialized"); | |
575 | |
576 if (is_active(cur)) { | |
577 TRACE_LINEAR_SCAN(3, tty->print_cr("backward branch")); | |
578 assert(is_visited(cur), "block must be visisted when block is active"); | |
579 assert(parent != NULL, "must have parent"); | |
580 | |
581 cur->set(BlockBegin::linear_scan_loop_header_flag); | |
582 cur->set(BlockBegin::backward_branch_target_flag); | |
583 | |
584 parent->set(BlockBegin::linear_scan_loop_end_flag); | |
428
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585 |
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586 // When a loop header is also the start of an exception handler, then the backward branch is |
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587 // an exception edge. Because such edges are usually critical edges which cannot be split, the |
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588 // loop must be excluded here from processing. |
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589 if (cur->is_set(BlockBegin::exception_entry_flag)) { |
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590 // Make sure that dominators are correct in this weird situation |
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591 _iterative_dominators = true; |
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592 return; |
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593 } |
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594 assert(parent->number_of_sux() == 1 && parent->sux_at(0) == cur, |
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595 "loop end blocks must have one successor (critical edges are split)"); |
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596 |
0 | 597 _loop_end_blocks.append(parent); |
598 return; | |
599 } | |
600 | |
601 // increment number of incoming forward branches | |
602 inc_forward_branches(cur); | |
603 | |
604 if (is_visited(cur)) { | |
605 TRACE_LINEAR_SCAN(3, tty->print_cr("block already visited")); | |
606 return; | |
607 } | |
608 | |
609 _num_blocks++; | |
610 set_visited(cur); | |
611 set_active(cur); | |
612 | |
613 // recursive call for all successors | |
614 int i; | |
615 for (i = cur->number_of_sux() - 1; i >= 0; i--) { | |
616 count_edges(cur->sux_at(i), cur); | |
617 } | |
618 for (i = cur->number_of_exception_handlers() - 1; i >= 0; i--) { | |
619 count_edges(cur->exception_handler_at(i), cur); | |
620 } | |
621 | |
622 clear_active(cur); | |
623 | |
624 // Each loop has a unique number. | |
625 // When multiple loops are nested, assign_loop_depth assumes that the | |
626 // innermost loop has the lowest number. This is guaranteed by setting | |
627 // the loop number after the recursive calls for the successors above | |
628 // have returned. | |
629 if (cur->is_set(BlockBegin::linear_scan_loop_header_flag)) { | |
630 assert(cur->loop_index() == -1, "cannot set loop-index twice"); | |
631 TRACE_LINEAR_SCAN(3, tty->print_cr("Block B%d is loop header of loop %d", cur->block_id(), _num_loops)); | |
632 | |
633 cur->set_loop_index(_num_loops); | |
8860 | 634 _loop_headers.append(cur); |
0 | 635 _num_loops++; |
636 } | |
637 | |
638 TRACE_LINEAR_SCAN(3, tty->print_cr("Finished count_edges for block B%d", cur->block_id())); | |
639 } | |
640 | |
641 | |
642 void ComputeLinearScanOrder::mark_loops() { | |
643 TRACE_LINEAR_SCAN(3, tty->print_cr("----- marking loops")); | |
644 | |
645 _loop_map = BitMap2D(_num_loops, _max_block_id); | |
646 _loop_map.clear(); | |
647 | |
648 for (int i = _loop_end_blocks.length() - 1; i >= 0; i--) { | |
649 BlockBegin* loop_end = _loop_end_blocks.at(i); | |
650 BlockBegin* loop_start = loop_end->sux_at(0); | |
651 int loop_idx = loop_start->loop_index(); | |
652 | |
653 TRACE_LINEAR_SCAN(3, tty->print_cr("Processing loop from B%d to B%d (loop %d):", loop_start->block_id(), loop_end->block_id(), loop_idx)); | |
654 assert(loop_end->is_set(BlockBegin::linear_scan_loop_end_flag), "loop end flag must be set"); | |
655 assert(loop_end->number_of_sux() == 1, "incorrect number of successors"); | |
656 assert(loop_start->is_set(BlockBegin::linear_scan_loop_header_flag), "loop header flag must be set"); | |
657 assert(loop_idx >= 0 && loop_idx < _num_loops, "loop index not set"); | |
658 assert(_work_list.is_empty(), "work list must be empty before processing"); | |
659 | |
660 // add the end-block of the loop to the working list | |
661 _work_list.push(loop_end); | |
662 set_block_in_loop(loop_idx, loop_end); | |
663 do { | |
664 BlockBegin* cur = _work_list.pop(); | |
665 | |
666 TRACE_LINEAR_SCAN(3, tty->print_cr(" processing B%d", cur->block_id())); | |
667 assert(is_block_in_loop(loop_idx, cur), "bit in loop map must be set when block is in work list"); | |
668 | |
669 // recursive processing of all predecessors ends when start block of loop is reached | |
670 if (cur != loop_start && !cur->is_set(BlockBegin::osr_entry_flag)) { | |
671 for (int j = cur->number_of_preds() - 1; j >= 0; j--) { | |
672 BlockBegin* pred = cur->pred_at(j); | |
673 | |
674 if (!is_block_in_loop(loop_idx, pred) /*&& !pred->is_set(BlockBeginosr_entry_flag)*/) { | |
675 // this predecessor has not been processed yet, so add it to work list | |
676 TRACE_LINEAR_SCAN(3, tty->print_cr(" pushing B%d", pred->block_id())); | |
677 _work_list.push(pred); | |
678 set_block_in_loop(loop_idx, pred); | |
679 } | |
680 } | |
681 } | |
682 } while (!_work_list.is_empty()); | |
683 } | |
684 } | |
685 | |
686 | |
687 // check for non-natural loops (loops where the loop header does not dominate | |
688 // all other loop blocks = loops with mulitple entries). | |
689 // such loops are ignored | |
690 void ComputeLinearScanOrder::clear_non_natural_loops(BlockBegin* start_block) { | |
691 for (int i = _num_loops - 1; i >= 0; i--) { | |
692 if (is_block_in_loop(i, start_block)) { | |
693 // loop i contains the entry block of the method | |
694 // -> this is not a natural loop, so ignore it | |
695 TRACE_LINEAR_SCAN(2, tty->print_cr("Loop %d is non-natural, so it is ignored", i)); | |
696 | |
8860 | 697 BlockBegin *loop_header = _loop_headers.at(i); |
698 assert(loop_header->is_set(BlockBegin::linear_scan_loop_header_flag), "Must be loop header"); | |
699 | |
700 for (int j = 0; j < loop_header->number_of_preds(); j++) { | |
701 BlockBegin *pred = loop_header->pred_at(j); | |
702 pred->clear(BlockBegin::linear_scan_loop_end_flag); | |
703 } | |
704 | |
705 loop_header->clear(BlockBegin::linear_scan_loop_header_flag); | |
706 | |
0 | 707 for (int block_id = _max_block_id - 1; block_id >= 0; block_id--) { |
708 clear_block_in_loop(i, block_id); | |
709 } | |
710 _iterative_dominators = true; | |
711 } | |
712 } | |
713 } | |
714 | |
715 void ComputeLinearScanOrder::assign_loop_depth(BlockBegin* start_block) { | |
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716 TRACE_LINEAR_SCAN(3, tty->print_cr("----- computing loop-depth and weight")); |
0 | 717 init_visited(); |
718 | |
719 assert(_work_list.is_empty(), "work list must be empty before processing"); | |
720 _work_list.append(start_block); | |
721 | |
722 do { | |
723 BlockBegin* cur = _work_list.pop(); | |
724 | |
725 if (!is_visited(cur)) { | |
726 set_visited(cur); | |
727 TRACE_LINEAR_SCAN(4, tty->print_cr("Computing loop depth for block B%d", cur->block_id())); | |
728 | |
729 // compute loop-depth and loop-index for the block | |
730 assert(cur->loop_depth() == 0, "cannot set loop-depth twice"); | |
731 int i; | |
732 int loop_depth = 0; | |
733 int min_loop_idx = -1; | |
734 for (i = _num_loops - 1; i >= 0; i--) { | |
735 if (is_block_in_loop(i, cur)) { | |
736 loop_depth++; | |
737 min_loop_idx = i; | |
738 } | |
739 } | |
740 cur->set_loop_depth(loop_depth); | |
741 cur->set_loop_index(min_loop_idx); | |
742 | |
743 // append all unvisited successors to work list | |
744 for (i = cur->number_of_sux() - 1; i >= 0; i--) { | |
745 _work_list.append(cur->sux_at(i)); | |
746 } | |
747 for (i = cur->number_of_exception_handlers() - 1; i >= 0; i--) { | |
748 _work_list.append(cur->exception_handler_at(i)); | |
749 } | |
750 } | |
751 } while (!_work_list.is_empty()); | |
752 } | |
753 | |
754 | |
755 BlockBegin* ComputeLinearScanOrder::common_dominator(BlockBegin* a, BlockBegin* b) { | |
756 assert(a != NULL && b != NULL, "must have input blocks"); | |
757 | |
758 _dominator_blocks.clear(); | |
759 while (a != NULL) { | |
760 _dominator_blocks.set_bit(a->block_id()); | |
761 assert(a->dominator() != NULL || a == _linear_scan_order->at(0), "dominator must be initialized"); | |
762 a = a->dominator(); | |
763 } | |
764 while (b != NULL && !_dominator_blocks.at(b->block_id())) { | |
765 assert(b->dominator() != NULL || b == _linear_scan_order->at(0), "dominator must be initialized"); | |
766 b = b->dominator(); | |
767 } | |
768 | |
769 assert(b != NULL, "could not find dominator"); | |
770 return b; | |
771 } | |
772 | |
773 void ComputeLinearScanOrder::compute_dominator(BlockBegin* cur, BlockBegin* parent) { | |
774 if (cur->dominator() == NULL) { | |
775 TRACE_LINEAR_SCAN(4, tty->print_cr("DOM: initializing dominator of B%d to B%d", cur->block_id(), parent->block_id())); | |
776 cur->set_dominator(parent); | |
777 | |
778 } else if (!(cur->is_set(BlockBegin::linear_scan_loop_header_flag) && parent->is_set(BlockBegin::linear_scan_loop_end_flag))) { | |
779 TRACE_LINEAR_SCAN(4, tty->print_cr("DOM: computing dominator of B%d: common dominator of B%d and B%d is B%d", cur->block_id(), parent->block_id(), cur->dominator()->block_id(), common_dominator(cur->dominator(), parent)->block_id())); | |
8860 | 780 // Does not hold for exception blocks |
781 assert(cur->number_of_preds() > 1 || cur->is_set(BlockBegin::exception_entry_flag), ""); | |
0 | 782 cur->set_dominator(common_dominator(cur->dominator(), parent)); |
783 } | |
8860 | 784 |
785 // Additional edge to xhandler of all our successors | |
786 // range check elimination needs that the state at the end of a | |
787 // block be valid in every block it dominates so cur must dominate | |
788 // the exception handlers of its successors. | |
789 int num_cur_xhandler = cur->number_of_exception_handlers(); | |
790 for (int j = 0; j < num_cur_xhandler; j++) { | |
791 BlockBegin* xhandler = cur->exception_handler_at(j); | |
792 compute_dominator(xhandler, parent); | |
793 } | |
0 | 794 } |
795 | |
796 | |
797 int ComputeLinearScanOrder::compute_weight(BlockBegin* cur) { | |
798 BlockBegin* single_sux = NULL; | |
799 if (cur->number_of_sux() == 1) { | |
800 single_sux = cur->sux_at(0); | |
801 } | |
802 | |
803 // limit loop-depth to 15 bit (only for security reason, it will never be so big) | |
804 int weight = (cur->loop_depth() & 0x7FFF) << 16; | |
805 | |
806 // general macro for short definition of weight flags | |
807 // the first instance of INC_WEIGHT_IF has the highest priority | |
808 int cur_bit = 15; | |
809 #define INC_WEIGHT_IF(condition) if ((condition)) { weight |= (1 << cur_bit); } cur_bit--; | |
810 | |
811 // this is necessery for the (very rare) case that two successing blocks have | |
812 // the same loop depth, but a different loop index (can happen for endless loops | |
813 // with exception handlers) | |
814 INC_WEIGHT_IF(!cur->is_set(BlockBegin::linear_scan_loop_header_flag)); | |
815 | |
816 // loop end blocks (blocks that end with a backward branch) are added | |
817 // after all other blocks of the loop. | |
818 INC_WEIGHT_IF(!cur->is_set(BlockBegin::linear_scan_loop_end_flag)); | |
819 | |
820 // critical edge split blocks are prefered because than they have a bigger | |
821 // proability to be completely empty | |
822 INC_WEIGHT_IF(cur->is_set(BlockBegin::critical_edge_split_flag)); | |
823 | |
824 // exceptions should not be thrown in normal control flow, so these blocks | |
825 // are added as late as possible | |
826 INC_WEIGHT_IF(cur->end()->as_Throw() == NULL && (single_sux == NULL || single_sux->end()->as_Throw() == NULL)); | |
827 INC_WEIGHT_IF(cur->end()->as_Return() == NULL && (single_sux == NULL || single_sux->end()->as_Return() == NULL)); | |
828 | |
829 // exceptions handlers are added as late as possible | |
830 INC_WEIGHT_IF(!cur->is_set(BlockBegin::exception_entry_flag)); | |
831 | |
832 // guarantee that weight is > 0 | |
833 weight |= 1; | |
834 | |
835 #undef INC_WEIGHT_IF | |
836 assert(cur_bit >= 0, "too many flags"); | |
837 assert(weight > 0, "weight cannot become negative"); | |
838 | |
839 return weight; | |
840 } | |
841 | |
842 bool ComputeLinearScanOrder::ready_for_processing(BlockBegin* cur) { | |
843 // Discount the edge just traveled. | |
844 // When the number drops to zero, all forward branches were processed | |
845 if (dec_forward_branches(cur) != 0) { | |
846 return false; | |
847 } | |
848 | |
849 assert(_linear_scan_order->index_of(cur) == -1, "block already processed (block can be ready only once)"); | |
850 assert(_work_list.index_of(cur) == -1, "block already in work-list (block can be ready only once)"); | |
851 return true; | |
852 } | |
853 | |
854 void ComputeLinearScanOrder::sort_into_work_list(BlockBegin* cur) { | |
855 assert(_work_list.index_of(cur) == -1, "block already in work list"); | |
856 | |
857 int cur_weight = compute_weight(cur); | |
858 | |
859 // the linear_scan_number is used to cache the weight of a block | |
860 cur->set_linear_scan_number(cur_weight); | |
861 | |
862 #ifndef PRODUCT | |
863 if (StressLinearScan) { | |
864 _work_list.insert_before(0, cur); | |
865 return; | |
866 } | |
867 #endif | |
868 | |
869 _work_list.append(NULL); // provide space for new element | |
870 | |
871 int insert_idx = _work_list.length() - 1; | |
872 while (insert_idx > 0 && _work_list.at(insert_idx - 1)->linear_scan_number() > cur_weight) { | |
873 _work_list.at_put(insert_idx, _work_list.at(insert_idx - 1)); | |
874 insert_idx--; | |
875 } | |
876 _work_list.at_put(insert_idx, cur); | |
877 | |
878 TRACE_LINEAR_SCAN(3, tty->print_cr("Sorted B%d into worklist. new worklist:", cur->block_id())); | |
879 TRACE_LINEAR_SCAN(3, for (int i = 0; i < _work_list.length(); i++) tty->print_cr("%8d B%2d weight:%6x", i, _work_list.at(i)->block_id(), _work_list.at(i)->linear_scan_number())); | |
880 | |
881 #ifdef ASSERT | |
882 for (int i = 0; i < _work_list.length(); i++) { | |
883 assert(_work_list.at(i)->linear_scan_number() > 0, "weight not set"); | |
884 assert(i == 0 || _work_list.at(i - 1)->linear_scan_number() <= _work_list.at(i)->linear_scan_number(), "incorrect order in worklist"); | |
885 } | |
886 #endif | |
887 } | |
888 | |
889 void ComputeLinearScanOrder::append_block(BlockBegin* cur) { | |
890 TRACE_LINEAR_SCAN(3, tty->print_cr("appending block B%d (weight 0x%6x) to linear-scan order", cur->block_id(), cur->linear_scan_number())); | |
891 assert(_linear_scan_order->index_of(cur) == -1, "cannot add the same block twice"); | |
892 | |
893 // currently, the linear scan order and code emit order are equal. | |
894 // therefore the linear_scan_number and the weight of a block must also | |
895 // be equal. | |
896 cur->set_linear_scan_number(_linear_scan_order->length()); | |
897 _linear_scan_order->append(cur); | |
898 } | |
899 | |
900 void ComputeLinearScanOrder::compute_order(BlockBegin* start_block) { | |
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901 TRACE_LINEAR_SCAN(3, tty->print_cr("----- computing final block order")); |
0 | 902 |
903 // the start block is always the first block in the linear scan order | |
904 _linear_scan_order = new BlockList(_num_blocks); | |
905 append_block(start_block); | |
906 | |
907 assert(start_block->end()->as_Base() != NULL, "start block must end with Base-instruction"); | |
908 BlockBegin* std_entry = ((Base*)start_block->end())->std_entry(); | |
909 BlockBegin* osr_entry = ((Base*)start_block->end())->osr_entry(); | |
910 | |
911 BlockBegin* sux_of_osr_entry = NULL; | |
912 if (osr_entry != NULL) { | |
913 // special handling for osr entry: | |
914 // ignore the edge between the osr entry and its successor for processing | |
915 // the osr entry block is added manually below | |
916 assert(osr_entry->number_of_sux() == 1, "osr entry must have exactly one successor"); | |
917 assert(osr_entry->sux_at(0)->number_of_preds() >= 2, "sucessor of osr entry must have two predecessors (otherwise it is not present in normal control flow"); | |
918 | |
919 sux_of_osr_entry = osr_entry->sux_at(0); | |
920 dec_forward_branches(sux_of_osr_entry); | |
921 | |
922 compute_dominator(osr_entry, start_block); | |
923 _iterative_dominators = true; | |
924 } | |
925 compute_dominator(std_entry, start_block); | |
926 | |
927 // start processing with standard entry block | |
928 assert(_work_list.is_empty(), "list must be empty before processing"); | |
929 | |
930 if (ready_for_processing(std_entry)) { | |
931 sort_into_work_list(std_entry); | |
932 } else { | |
933 assert(false, "the std_entry must be ready for processing (otherwise, the method has no start block)"); | |
934 } | |
935 | |
936 do { | |
937 BlockBegin* cur = _work_list.pop(); | |
938 | |
939 if (cur == sux_of_osr_entry) { | |
940 // the osr entry block is ignored in normal processing, it is never added to the | |
941 // work list. Instead, it is added as late as possible manually here. | |
942 append_block(osr_entry); | |
943 compute_dominator(cur, osr_entry); | |
944 } | |
945 append_block(cur); | |
946 | |
947 int i; | |
948 int num_sux = cur->number_of_sux(); | |
949 // changed loop order to get "intuitive" order of if- and else-blocks | |
950 for (i = 0; i < num_sux; i++) { | |
951 BlockBegin* sux = cur->sux_at(i); | |
952 compute_dominator(sux, cur); | |
953 if (ready_for_processing(sux)) { | |
954 sort_into_work_list(sux); | |
955 } | |
956 } | |
957 num_sux = cur->number_of_exception_handlers(); | |
958 for (i = 0; i < num_sux; i++) { | |
959 BlockBegin* sux = cur->exception_handler_at(i); | |
960 if (ready_for_processing(sux)) { | |
961 sort_into_work_list(sux); | |
962 } | |
963 } | |
964 } while (_work_list.length() > 0); | |
965 } | |
966 | |
967 | |
968 bool ComputeLinearScanOrder::compute_dominators_iter() { | |
969 bool changed = false; | |
970 int num_blocks = _linear_scan_order->length(); | |
971 | |
972 assert(_linear_scan_order->at(0)->dominator() == NULL, "must not have dominator"); | |
973 assert(_linear_scan_order->at(0)->number_of_preds() == 0, "must not have predecessors"); | |
974 for (int i = 1; i < num_blocks; i++) { | |
975 BlockBegin* block = _linear_scan_order->at(i); | |
976 | |
977 BlockBegin* dominator = block->pred_at(0); | |
978 int num_preds = block->number_of_preds(); | |
8860 | 979 |
980 TRACE_LINEAR_SCAN(4, tty->print_cr("DOM: Processing B%d", block->block_id())); | |
981 | |
982 for (int j = 0; j < num_preds; j++) { | |
983 | |
984 BlockBegin *pred = block->pred_at(j); | |
985 TRACE_LINEAR_SCAN(4, tty->print_cr(" DOM: Subrocessing B%d", pred->block_id())); | |
986 | |
987 if (block->is_set(BlockBegin::exception_entry_flag)) { | |
988 dominator = common_dominator(dominator, pred); | |
989 int num_pred_preds = pred->number_of_preds(); | |
990 for (int k = 0; k < num_pred_preds; k++) { | |
991 dominator = common_dominator(dominator, pred->pred_at(k)); | |
992 } | |
993 } else { | |
994 dominator = common_dominator(dominator, pred); | |
995 } | |
0 | 996 } |
997 | |
998 if (dominator != block->dominator()) { | |
999 TRACE_LINEAR_SCAN(4, tty->print_cr("DOM: updating dominator of B%d from B%d to B%d", block->block_id(), block->dominator()->block_id(), dominator->block_id())); | |
1000 | |
1001 block->set_dominator(dominator); | |
1002 changed = true; | |
1003 } | |
1004 } | |
1005 return changed; | |
1006 } | |
1007 | |
1008 void ComputeLinearScanOrder::compute_dominators() { | |
1009 TRACE_LINEAR_SCAN(3, tty->print_cr("----- computing dominators (iterative computation reqired: %d)", _iterative_dominators)); | |
1010 | |
1011 // iterative computation of dominators is only required for methods with non-natural loops | |
1012 // and OSR-methods. For all other methods, the dominators computed when generating the | |
1013 // linear scan block order are correct. | |
1014 if (_iterative_dominators) { | |
1015 do { | |
1016 TRACE_LINEAR_SCAN(1, tty->print_cr("DOM: next iteration of fix-point calculation")); | |
1017 } while (compute_dominators_iter()); | |
1018 } | |
1019 | |
1020 // check that dominators are correct | |
1021 assert(!compute_dominators_iter(), "fix point not reached"); | |
8860 | 1022 |
1023 // Add Blocks to dominates-Array | |
1024 int num_blocks = _linear_scan_order->length(); | |
1025 for (int i = 0; i < num_blocks; i++) { | |
1026 BlockBegin* block = _linear_scan_order->at(i); | |
1027 | |
1028 BlockBegin *dom = block->dominator(); | |
1029 if (dom) { | |
1030 assert(dom->dominator_depth() != -1, "Dominator must have been visited before"); | |
1031 dom->dominates()->append(block); | |
1032 block->set_dominator_depth(dom->dominator_depth() + 1); | |
1033 } else { | |
1034 block->set_dominator_depth(0); | |
1035 } | |
1036 } | |
0 | 1037 } |
1038 | |
1039 | |
1040 #ifndef PRODUCT | |
1041 void ComputeLinearScanOrder::print_blocks() { | |
1042 if (TraceLinearScanLevel >= 2) { | |
1043 tty->print_cr("----- loop information:"); | |
1044 for (int block_idx = 0; block_idx < _linear_scan_order->length(); block_idx++) { | |
1045 BlockBegin* cur = _linear_scan_order->at(block_idx); | |
1046 | |
1047 tty->print("%4d: B%2d: ", cur->linear_scan_number(), cur->block_id()); | |
1048 for (int loop_idx = 0; loop_idx < _num_loops; loop_idx++) { | |
1049 tty->print ("%d ", is_block_in_loop(loop_idx, cur)); | |
1050 } | |
1051 tty->print_cr(" -> loop_index: %2d, loop_depth: %2d", cur->loop_index(), cur->loop_depth()); | |
1052 } | |
1053 } | |
1054 | |
1055 if (TraceLinearScanLevel >= 1) { | |
1056 tty->print_cr("----- linear-scan block order:"); | |
1057 for (int block_idx = 0; block_idx < _linear_scan_order->length(); block_idx++) { | |
1058 BlockBegin* cur = _linear_scan_order->at(block_idx); | |
1059 tty->print("%4d: B%2d loop: %2d depth: %2d", cur->linear_scan_number(), cur->block_id(), cur->loop_index(), cur->loop_depth()); | |
1060 | |
1061 tty->print(cur->is_set(BlockBegin::exception_entry_flag) ? " ex" : " "); | |
1062 tty->print(cur->is_set(BlockBegin::critical_edge_split_flag) ? " ce" : " "); | |
1063 tty->print(cur->is_set(BlockBegin::linear_scan_loop_header_flag) ? " lh" : " "); | |
1064 tty->print(cur->is_set(BlockBegin::linear_scan_loop_end_flag) ? " le" : " "); | |
1065 | |
1066 if (cur->dominator() != NULL) { | |
1067 tty->print(" dom: B%d ", cur->dominator()->block_id()); | |
1068 } else { | |
1069 tty->print(" dom: NULL "); | |
1070 } | |
1071 | |
1072 if (cur->number_of_preds() > 0) { | |
1073 tty->print(" preds: "); | |
1074 for (int j = 0; j < cur->number_of_preds(); j++) { | |
1075 BlockBegin* pred = cur->pred_at(j); | |
1076 tty->print("B%d ", pred->block_id()); | |
1077 } | |
1078 } | |
1079 if (cur->number_of_sux() > 0) { | |
1080 tty->print(" sux: "); | |
1081 for (int j = 0; j < cur->number_of_sux(); j++) { | |
1082 BlockBegin* sux = cur->sux_at(j); | |
1083 tty->print("B%d ", sux->block_id()); | |
1084 } | |
1085 } | |
1086 if (cur->number_of_exception_handlers() > 0) { | |
1087 tty->print(" ex: "); | |
1088 for (int j = 0; j < cur->number_of_exception_handlers(); j++) { | |
1089 BlockBegin* ex = cur->exception_handler_at(j); | |
1090 tty->print("B%d ", ex->block_id()); | |
1091 } | |
1092 } | |
1093 tty->cr(); | |
1094 } | |
1095 } | |
1096 } | |
1097 #endif | |
1098 | |
1099 #ifdef ASSERT | |
1100 void ComputeLinearScanOrder::verify() { | |
1101 assert(_linear_scan_order->length() == _num_blocks, "wrong number of blocks in list"); | |
1102 | |
1103 if (StressLinearScan) { | |
1104 // blocks are scrambled when StressLinearScan is used | |
1105 return; | |
1106 } | |
1107 | |
1108 // check that all successors of a block have a higher linear-scan-number | |
1109 // and that all predecessors of a block have a lower linear-scan-number | |
1110 // (only backward branches of loops are ignored) | |
1111 int i; | |
1112 for (i = 0; i < _linear_scan_order->length(); i++) { | |
1113 BlockBegin* cur = _linear_scan_order->at(i); | |
1114 | |
1115 assert(cur->linear_scan_number() == i, "incorrect linear_scan_number"); | |
1116 assert(cur->linear_scan_number() >= 0 && cur->linear_scan_number() == _linear_scan_order->index_of(cur), "incorrect linear_scan_number"); | |
1117 | |
1118 int j; | |
1119 for (j = cur->number_of_sux() - 1; j >= 0; j--) { | |
1120 BlockBegin* sux = cur->sux_at(j); | |
1121 | |
1122 assert(sux->linear_scan_number() >= 0 && sux->linear_scan_number() == _linear_scan_order->index_of(sux), "incorrect linear_scan_number"); | |
8860 | 1123 if (!sux->is_set(BlockBegin::backward_branch_target_flag)) { |
0 | 1124 assert(cur->linear_scan_number() < sux->linear_scan_number(), "invalid order"); |
1125 } | |
1126 if (cur->loop_depth() == sux->loop_depth()) { | |
1127 assert(cur->loop_index() == sux->loop_index() || sux->is_set(BlockBegin::linear_scan_loop_header_flag), "successing blocks with same loop depth must have same loop index"); | |
1128 } | |
1129 } | |
1130 | |
1131 for (j = cur->number_of_preds() - 1; j >= 0; j--) { | |
1132 BlockBegin* pred = cur->pred_at(j); | |
1133 | |
1134 assert(pred->linear_scan_number() >= 0 && pred->linear_scan_number() == _linear_scan_order->index_of(pred), "incorrect linear_scan_number"); | |
8860 | 1135 if (!cur->is_set(BlockBegin::backward_branch_target_flag)) { |
0 | 1136 assert(cur->linear_scan_number() > pred->linear_scan_number(), "invalid order"); |
1137 } | |
1138 if (cur->loop_depth() == pred->loop_depth()) { | |
1139 assert(cur->loop_index() == pred->loop_index() || cur->is_set(BlockBegin::linear_scan_loop_header_flag), "successing blocks with same loop depth must have same loop index"); | |
1140 } | |
1141 | |
1142 assert(cur->dominator()->linear_scan_number() <= cur->pred_at(j)->linear_scan_number(), "dominator must be before predecessors"); | |
1143 } | |
1144 | |
1145 // check dominator | |
1146 if (i == 0) { | |
1147 assert(cur->dominator() == NULL, "first block has no dominator"); | |
1148 } else { | |
1149 assert(cur->dominator() != NULL, "all but first block must have dominator"); | |
1150 } | |
8860 | 1151 // Assertion does not hold for exception handlers |
1152 assert(cur->number_of_preds() != 1 || cur->dominator() == cur->pred_at(0) || cur->is_set(BlockBegin::exception_entry_flag), "Single predecessor must also be dominator"); | |
0 | 1153 } |
1154 | |
1155 // check that all loops are continuous | |
1156 for (int loop_idx = 0; loop_idx < _num_loops; loop_idx++) { | |
1157 int block_idx = 0; | |
1158 assert(!is_block_in_loop(loop_idx, _linear_scan_order->at(block_idx)), "the first block must not be present in any loop"); | |
1159 | |
1160 // skip blocks before the loop | |
1161 while (block_idx < _num_blocks && !is_block_in_loop(loop_idx, _linear_scan_order->at(block_idx))) { | |
1162 block_idx++; | |
1163 } | |
1164 // skip blocks of loop | |
1165 while (block_idx < _num_blocks && is_block_in_loop(loop_idx, _linear_scan_order->at(block_idx))) { | |
1166 block_idx++; | |
1167 } | |
1168 // after the first non-loop block, there must not be another loop-block | |
1169 while (block_idx < _num_blocks) { | |
1170 assert(!is_block_in_loop(loop_idx, _linear_scan_order->at(block_idx)), "loop not continuous in linear-scan order"); | |
1171 block_idx++; | |
1172 } | |
1173 } | |
1174 } | |
1175 #endif | |
1176 | |
1177 | |
1178 void IR::compute_code() { | |
1179 assert(is_valid(), "IR must be valid"); | |
1180 | |
1783 | 1181 ComputeLinearScanOrder compute_order(compilation(), start()); |
0 | 1182 _num_loops = compute_order.num_loops(); |
1183 _code = compute_order.linear_scan_order(); | |
1184 } | |
1185 | |
1186 | |
1187 void IR::compute_use_counts() { | |
1188 // make sure all values coming out of this block get evaluated. | |
1189 int num_blocks = _code->length(); | |
1190 for (int i = 0; i < num_blocks; i++) { | |
1191 _code->at(i)->end()->state()->pin_stack_for_linear_scan(); | |
1192 } | |
1193 | |
1194 // compute use counts | |
1195 UseCountComputer::compute(_code); | |
1196 } | |
1197 | |
1198 | |
1199 void IR::iterate_preorder(BlockClosure* closure) { | |
1200 assert(is_valid(), "IR must be valid"); | |
1201 start()->iterate_preorder(closure); | |
1202 } | |
1203 | |
1204 | |
1205 void IR::iterate_postorder(BlockClosure* closure) { | |
1206 assert(is_valid(), "IR must be valid"); | |
1207 start()->iterate_postorder(closure); | |
1208 } | |
1209 | |
1210 void IR::iterate_linear_scan_order(BlockClosure* closure) { | |
1211 linear_scan_order()->iterate_forward(closure); | |
1212 } | |
1213 | |
1214 | |
1215 #ifndef PRODUCT | |
1216 class BlockPrinter: public BlockClosure { | |
1217 private: | |
1218 InstructionPrinter* _ip; | |
1219 bool _cfg_only; | |
1220 bool _live_only; | |
1221 | |
1222 public: | |
1223 BlockPrinter(InstructionPrinter* ip, bool cfg_only, bool live_only = false) { | |
1224 _ip = ip; | |
1225 _cfg_only = cfg_only; | |
1226 _live_only = live_only; | |
1227 } | |
1228 | |
1229 virtual void block_do(BlockBegin* block) { | |
1230 if (_cfg_only) { | |
1231 _ip->print_instr(block); tty->cr(); | |
1232 } else { | |
1233 block->print_block(*_ip, _live_only); | |
1234 } | |
1235 } | |
1236 }; | |
1237 | |
1238 | |
1239 void IR::print(BlockBegin* start, bool cfg_only, bool live_only) { | |
1240 ttyLocker ttyl; | |
1241 InstructionPrinter ip(!cfg_only); | |
1242 BlockPrinter bp(&ip, cfg_only, live_only); | |
1243 start->iterate_preorder(&bp); | |
1244 tty->cr(); | |
1245 } | |
1246 | |
1247 void IR::print(bool cfg_only, bool live_only) { | |
1248 if (is_valid()) { | |
1249 print(start(), cfg_only, live_only); | |
1250 } else { | |
1251 tty->print_cr("invalid IR"); | |
1252 } | |
1253 } | |
1254 | |
1255 | |
1256 define_array(BlockListArray, BlockList*) | |
1257 define_stack(BlockListList, BlockListArray) | |
1258 | |
1259 class PredecessorValidator : public BlockClosure { | |
1260 private: | |
1261 BlockListList* _predecessors; | |
1262 BlockList* _blocks; | |
1263 | |
1264 static int cmp(BlockBegin** a, BlockBegin** b) { | |
1265 return (*a)->block_id() - (*b)->block_id(); | |
1266 } | |
1267 | |
1268 public: | |
1269 PredecessorValidator(IR* hir) { | |
1270 ResourceMark rm; | |
1271 _predecessors = new BlockListList(BlockBegin::number_of_blocks(), NULL); | |
1272 _blocks = new BlockList(); | |
1273 | |
1274 int i; | |
1275 hir->start()->iterate_preorder(this); | |
1276 if (hir->code() != NULL) { | |
1277 assert(hir->code()->length() == _blocks->length(), "must match"); | |
1278 for (i = 0; i < _blocks->length(); i++) { | |
1279 assert(hir->code()->contains(_blocks->at(i)), "should be in both lists"); | |
1280 } | |
1281 } | |
1282 | |
1283 for (i = 0; i < _blocks->length(); i++) { | |
1284 BlockBegin* block = _blocks->at(i); | |
1285 BlockList* preds = _predecessors->at(block->block_id()); | |
1286 if (preds == NULL) { | |
1287 assert(block->number_of_preds() == 0, "should be the same"); | |
1288 continue; | |
1289 } | |
1290 | |
1291 // clone the pred list so we can mutate it | |
1292 BlockList* pred_copy = new BlockList(); | |
1293 int j; | |
1294 for (j = 0; j < block->number_of_preds(); j++) { | |
1295 pred_copy->append(block->pred_at(j)); | |
1296 } | |
1297 // sort them in the same order | |
1298 preds->sort(cmp); | |
1299 pred_copy->sort(cmp); | |
1300 int length = MIN2(preds->length(), block->number_of_preds()); | |
1301 for (j = 0; j < block->number_of_preds(); j++) { | |
1302 assert(preds->at(j) == pred_copy->at(j), "must match"); | |
1303 } | |
1304 | |
1305 assert(preds->length() == block->number_of_preds(), "should be the same"); | |
1306 } | |
1307 } | |
1308 | |
1309 virtual void block_do(BlockBegin* block) { | |
1310 _blocks->append(block); | |
1311 BlockEnd* be = block->end(); | |
1312 int n = be->number_of_sux(); | |
1313 int i; | |
1314 for (i = 0; i < n; i++) { | |
1315 BlockBegin* sux = be->sux_at(i); | |
1316 assert(!sux->is_set(BlockBegin::exception_entry_flag), "must not be xhandler"); | |
1317 | |
1318 BlockList* preds = _predecessors->at_grow(sux->block_id(), NULL); | |
1319 if (preds == NULL) { | |
1320 preds = new BlockList(); | |
1321 _predecessors->at_put(sux->block_id(), preds); | |
1322 } | |
1323 preds->append(block); | |
1324 } | |
1325 | |
1326 n = block->number_of_exception_handlers(); | |
1327 for (i = 0; i < n; i++) { | |
1328 BlockBegin* sux = block->exception_handler_at(i); | |
1329 assert(sux->is_set(BlockBegin::exception_entry_flag), "must be xhandler"); | |
1330 | |
1331 BlockList* preds = _predecessors->at_grow(sux->block_id(), NULL); | |
1332 if (preds == NULL) { | |
1333 preds = new BlockList(); | |
1334 _predecessors->at_put(sux->block_id(), preds); | |
1335 } | |
1336 preds->append(block); | |
1337 } | |
1338 } | |
1339 }; | |
1340 | |
8860 | 1341 class VerifyBlockBeginField : public BlockClosure { |
1342 | |
1343 public: | |
1344 | |
1345 virtual void block_do(BlockBegin *block) { | |
1346 for ( Instruction *cur = block; cur != NULL; cur = cur->next()) { | |
1347 assert(cur->block() == block, "Block begin is not correct"); | |
1348 } | |
1349 } | |
1350 }; | |
1351 | |
0 | 1352 void IR::verify() { |
1353 #ifdef ASSERT | |
1354 PredecessorValidator pv(this); | |
8860 | 1355 VerifyBlockBeginField verifier; |
1356 this->iterate_postorder(&verifier); | |
0 | 1357 #endif |
1358 } | |
1359 | |
1360 #endif // PRODUCT | |
1361 | |
1584 | 1362 void SubstitutionResolver::visit(Value* v) { |
0 | 1363 Value v0 = *v; |
1364 if (v0) { | |
1365 Value vs = v0->subst(); | |
1366 if (vs != v0) { | |
1367 *v = v0->subst(); | |
1368 } | |
1369 } | |
1370 } | |
1371 | |
1372 #ifdef ASSERT | |
1584 | 1373 class SubstitutionChecker: public ValueVisitor { |
1374 void visit(Value* v) { | |
1375 Value v0 = *v; | |
1376 if (v0) { | |
1377 Value vs = v0->subst(); | |
1378 assert(vs == v0, "missed substitution"); | |
1379 } | |
0 | 1380 } |
1584 | 1381 }; |
0 | 1382 #endif |
1383 | |
1384 | |
1385 void SubstitutionResolver::block_do(BlockBegin* block) { | |
1386 Instruction* last = NULL; | |
1387 for (Instruction* n = block; n != NULL;) { | |
1584 | 1388 n->values_do(this); |
0 | 1389 // need to remove this instruction from the instruction stream |
1390 if (n->subst() != n) { | |
1391 assert(last != NULL, "must have last"); | |
1819 | 1392 last->set_next(n->next()); |
0 | 1393 } else { |
1394 last = n; | |
1395 } | |
1396 n = last->next(); | |
1397 } | |
1398 | |
1399 #ifdef ASSERT | |
1584 | 1400 SubstitutionChecker check_substitute; |
1401 if (block->state()) block->state()->values_do(&check_substitute); | |
1402 block->block_values_do(&check_substitute); | |
1403 if (block->end() && block->end()->state()) block->end()->state()->values_do(&check_substitute); | |
0 | 1404 #endif |
1405 } |