1 /*
2 * Copyright (c) 1997, 2014, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation.
8 *
9 * This code is distributed in the hope that it will be useful, but WITHOUT
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
12 * version 2 for more details (a copy is included in the LICENSE file that
13 * accompanied this code).
14 *
15 * You should have received a copy of the GNU General Public License version
16 * 2 along with this work; if not, write to the Free Software Foundation,
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18 *
19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 * or visit www.oracle.com if you need additional information or have any
21 * questions.
22 *
23 */
24
25 #include "precompiled.hpp"
26 #include "asm/macroAssembler.hpp"
27 #include "asm/macroAssembler.inline.hpp"
28 #include "ci/ciReplay.hpp"
29 #include "classfile/systemDictionary.hpp"
30 #include "code/exceptionHandlerTable.hpp"
31 #include "code/nmethod.hpp"
32 #include "compiler/compileBroker.hpp"
33 #include "compiler/compileLog.hpp"
34 #include "compiler/disassembler.hpp"
35 #include "compiler/oopMap.hpp"
36 #include "opto/addnode.hpp"
37 #include "opto/block.hpp"
38 #include "opto/c2compiler.hpp"
39 #include "opto/callGenerator.hpp"
40 #include "opto/callnode.hpp"
41 #include "opto/cfgnode.hpp"
42 #include "opto/chaitin.hpp"
43 #include "opto/compile.hpp"
44 #include "opto/connode.hpp"
45 #include "opto/divnode.hpp"
46 #include "opto/escape.hpp"
47 #include "opto/idealGraphPrinter.hpp"
48 #include "opto/loopnode.hpp"
49 #include "opto/machnode.hpp"
50 #include "opto/macro.hpp"
51 #include "opto/matcher.hpp"
52 #include "opto/mathexactnode.hpp"
53 #include "opto/memnode.hpp"
54 #include "opto/mulnode.hpp"
55 #include "opto/narrowptrnode.hpp"
56 #include "opto/node.hpp"
57 #include "opto/opcodes.hpp"
58 #include "opto/output.hpp"
59 #include "opto/parse.hpp"
60 #include "opto/phaseX.hpp"
61 #include "opto/rootnode.hpp"
62 #include "opto/runtime.hpp"
63 #include "opto/stringopts.hpp"
64 #include "opto/type.hpp"
65 #include "opto/vectornode.hpp"
66 #include "runtime/arguments.hpp"
67 #include "runtime/sharedRuntime.hpp"
68 #include "runtime/signature.hpp"
69 #include "runtime/stubRoutines.hpp"
70 #include "runtime/timer.hpp"
71 #include "trace/tracing.hpp"
72 #include "utilities/copy.hpp"
73
74
75 // -------------------- Compile::mach_constant_base_node -----------------------
76 // Constant table base node singleton.
77 MachConstantBaseNode* Compile::mach_constant_base_node() {
78 if (_mach_constant_base_node == NULL) {
79 _mach_constant_base_node = new MachConstantBaseNode();
80 _mach_constant_base_node->add_req(C->root());
81 }
82 return _mach_constant_base_node;
83 }
84
85
86 /// Support for intrinsics.
87
88 // Return the index at which m must be inserted (or already exists).
89 // The sort order is by the address of the ciMethod, with is_virtual as minor key.
90 int Compile::intrinsic_insertion_index(ciMethod* m, bool is_virtual) {
91 #ifdef ASSERT
92 for (int i = 1; i < _intrinsics->length(); i++) {
93 CallGenerator* cg1 = _intrinsics->at(i-1);
94 CallGenerator* cg2 = _intrinsics->at(i);
95 assert(cg1->method() != cg2->method()
96 ? cg1->method() < cg2->method()
97 : cg1->is_virtual() < cg2->is_virtual(),
98 "compiler intrinsics list must stay sorted");
99 }
100 #endif
101 // Binary search sorted list, in decreasing intervals [lo, hi].
102 int lo = 0, hi = _intrinsics->length()-1;
103 while (lo <= hi) {
104 int mid = (uint)(hi + lo) / 2;
105 ciMethod* mid_m = _intrinsics->at(mid)->method();
106 if (m < mid_m) {
107 hi = mid-1;
108 } else if (m > mid_m) {
109 lo = mid+1;
110 } else {
111 // look at minor sort key
112 bool mid_virt = _intrinsics->at(mid)->is_virtual();
113 if (is_virtual < mid_virt) {
114 hi = mid-1;
115 } else if (is_virtual > mid_virt) {
116 lo = mid+1;
117 } else {
118 return mid; // exact match
119 }
120 }
121 }
122 return lo; // inexact match
123 }
124
125 void Compile::register_intrinsic(CallGenerator* cg) {
126 if (_intrinsics == NULL) {
127 _intrinsics = new (comp_arena())GrowableArray<CallGenerator*>(comp_arena(), 60, 0, NULL);
128 }
129 // This code is stolen from ciObjectFactory::insert.
130 // Really, GrowableArray should have methods for
131 // insert_at, remove_at, and binary_search.
132 int len = _intrinsics->length();
133 int index = intrinsic_insertion_index(cg->method(), cg->is_virtual());
134 if (index == len) {
135 _intrinsics->append(cg);
136 } else {
137 #ifdef ASSERT
138 CallGenerator* oldcg = _intrinsics->at(index);
139 assert(oldcg->method() != cg->method() || oldcg->is_virtual() != cg->is_virtual(), "don't register twice");
140 #endif
141 _intrinsics->append(_intrinsics->at(len-1));
142 int pos;
143 for (pos = len-2; pos >= index; pos--) {
144 _intrinsics->at_put(pos+1,_intrinsics->at(pos));
145 }
146 _intrinsics->at_put(index, cg);
147 }
148 assert(find_intrinsic(cg->method(), cg->is_virtual()) == cg, "registration worked");
149 }
150
151 CallGenerator* Compile::find_intrinsic(ciMethod* m, bool is_virtual) {
152 assert(m->is_loaded(), "don't try this on unloaded methods");
153 if (_intrinsics != NULL) {
154 int index = intrinsic_insertion_index(m, is_virtual);
155 if (index < _intrinsics->length()
156 && _intrinsics->at(index)->method() == m
157 && _intrinsics->at(index)->is_virtual() == is_virtual) {
158 return _intrinsics->at(index);
159 }
160 }
161 // Lazily create intrinsics for intrinsic IDs well-known in the runtime.
162 if (m->intrinsic_id() != vmIntrinsics::_none &&
163 m->intrinsic_id() <= vmIntrinsics::LAST_COMPILER_INLINE) {
164 CallGenerator* cg = make_vm_intrinsic(m, is_virtual);
165 if (cg != NULL) {
166 // Save it for next time:
167 register_intrinsic(cg);
168 return cg;
169 } else {
170 gather_intrinsic_statistics(m->intrinsic_id(), is_virtual, _intrinsic_disabled);
171 }
172 }
173 return NULL;
174 }
175
176 // Compile:: register_library_intrinsics and make_vm_intrinsic are defined
177 // in library_call.cpp.
178
179
180 #ifndef PRODUCT
181 // statistics gathering...
182
183 juint Compile::_intrinsic_hist_count[vmIntrinsics::ID_LIMIT] = {0};
184 jubyte Compile::_intrinsic_hist_flags[vmIntrinsics::ID_LIMIT] = {0};
185
186 bool Compile::gather_intrinsic_statistics(vmIntrinsics::ID id, bool is_virtual, int flags) {
187 assert(id > vmIntrinsics::_none && id < vmIntrinsics::ID_LIMIT, "oob");
188 int oflags = _intrinsic_hist_flags[id];
189 assert(flags != 0, "what happened?");
190 if (is_virtual) {
191 flags |= _intrinsic_virtual;
192 }
193 bool changed = (flags != oflags);
194 if ((flags & _intrinsic_worked) != 0) {
195 juint count = (_intrinsic_hist_count[id] += 1);
196 if (count == 1) {
197 changed = true; // first time
198 }
199 // increment the overall count also:
200 _intrinsic_hist_count[vmIntrinsics::_none] += 1;
201 }
202 if (changed) {
203 if (((oflags ^ flags) & _intrinsic_virtual) != 0) {
204 // Something changed about the intrinsic's virtuality.
205 if ((flags & _intrinsic_virtual) != 0) {
206 // This is the first use of this intrinsic as a virtual call.
207 if (oflags != 0) {
208 // We already saw it as a non-virtual, so note both cases.
209 flags |= _intrinsic_both;
210 }
211 } else if ((oflags & _intrinsic_both) == 0) {
212 // This is the first use of this intrinsic as a non-virtual
213 flags |= _intrinsic_both;
214 }
215 }
216 _intrinsic_hist_flags[id] = (jubyte) (oflags | flags);
217 }
218 // update the overall flags also:
219 _intrinsic_hist_flags[vmIntrinsics::_none] |= (jubyte) flags;
220 return changed;
221 }
222
223 static char* format_flags(int flags, char* buf) {
224 buf[0] = 0;
225 if ((flags & Compile::_intrinsic_worked) != 0) strcat(buf, ",worked");
226 if ((flags & Compile::_intrinsic_failed) != 0) strcat(buf, ",failed");
227 if ((flags & Compile::_intrinsic_disabled) != 0) strcat(buf, ",disabled");
228 if ((flags & Compile::_intrinsic_virtual) != 0) strcat(buf, ",virtual");
229 if ((flags & Compile::_intrinsic_both) != 0) strcat(buf, ",nonvirtual");
230 if (buf[0] == 0) strcat(buf, ",");
231 assert(buf[0] == ',', "must be");
232 return &buf[1];
233 }
234
235 void Compile::print_intrinsic_statistics() {
236 char flagsbuf[100];
237 ttyLocker ttyl;
238 if (xtty != NULL) xtty->head("statistics type='intrinsic'");
239 tty->print_cr("Compiler intrinsic usage:");
240 juint total = _intrinsic_hist_count[vmIntrinsics::_none];
241 if (total == 0) total = 1; // avoid div0 in case of no successes
242 #define PRINT_STAT_LINE(name, c, f) \
243 tty->print_cr(" %4d (%4.1f%%) %s (%s)", (int)(c), ((c) * 100.0) / total, name, f);
244 for (int index = 1 + (int)vmIntrinsics::_none; index < (int)vmIntrinsics::ID_LIMIT; index++) {
245 vmIntrinsics::ID id = (vmIntrinsics::ID) index;
246 int flags = _intrinsic_hist_flags[id];
247 juint count = _intrinsic_hist_count[id];
248 if ((flags | count) != 0) {
249 PRINT_STAT_LINE(vmIntrinsics::name_at(id), count, format_flags(flags, flagsbuf));
250 }
251 }
252 PRINT_STAT_LINE("total", total, format_flags(_intrinsic_hist_flags[vmIntrinsics::_none], flagsbuf));
253 if (xtty != NULL) xtty->tail("statistics");
254 }
255
256 void Compile::print_statistics() {
257 { ttyLocker ttyl;
258 if (xtty != NULL) xtty->head("statistics type='opto'");
259 Parse::print_statistics();
260 PhaseCCP::print_statistics();
261 PhaseRegAlloc::print_statistics();
262 Scheduling::print_statistics();
263 PhasePeephole::print_statistics();
264 PhaseIdealLoop::print_statistics();
265 if (xtty != NULL) xtty->tail("statistics");
266 }
267 if (_intrinsic_hist_flags[vmIntrinsics::_none] != 0) {
268 // put this under its own <statistics> element.
269 print_intrinsic_statistics();
270 }
271 }
272 #endif //PRODUCT
273
274 // Support for bundling info
275 Bundle* Compile::node_bundling(const Node *n) {
276 assert(valid_bundle_info(n), "oob");
277 return &_node_bundling_base[n->_idx];
278 }
279
280 bool Compile::valid_bundle_info(const Node *n) {
281 return (_node_bundling_limit > n->_idx);
282 }
283
284
285 void Compile::gvn_replace_by(Node* n, Node* nn) {
286 for (DUIterator_Last imin, i = n->last_outs(imin); i >= imin; ) {
287 Node* use = n->last_out(i);
288 bool is_in_table = initial_gvn()->hash_delete(use);
289 uint uses_found = 0;
290 for (uint j = 0; j < use->len(); j++) {
291 if (use->in(j) == n) {
292 if (j < use->req())
293 use->set_req(j, nn);
294 else
295 use->set_prec(j, nn);
296 uses_found++;
297 }
298 }
299 if (is_in_table) {
300 // reinsert into table
301 initial_gvn()->hash_find_insert(use);
302 }
303 record_for_igvn(use);
304 i -= uses_found; // we deleted 1 or more copies of this edge
305 }
306 }
307
308
309 static inline bool not_a_node(const Node* n) {
310 if (n == NULL) return true;
311 if (((intptr_t)n & 1) != 0) return true; // uninitialized, etc.
312 if (*(address*)n == badAddress) return true; // kill by Node::destruct
313 return false;
314 }
315
316 // Identify all nodes that are reachable from below, useful.
317 // Use breadth-first pass that records state in a Unique_Node_List,
318 // recursive traversal is slower.
319 void Compile::identify_useful_nodes(Unique_Node_List &useful) {
320 int estimated_worklist_size = unique();
321 useful.map( estimated_worklist_size, NULL ); // preallocate space
322
323 // Initialize worklist
324 if (root() != NULL) { useful.push(root()); }
325 // If 'top' is cached, declare it useful to preserve cached node
326 if( cached_top_node() ) { useful.push(cached_top_node()); }
327
328 // Push all useful nodes onto the list, breadthfirst
329 for( uint next = 0; next < useful.size(); ++next ) {
330 assert( next < unique(), "Unique useful nodes < total nodes");
331 Node *n = useful.at(next);
332 uint max = n->len();
333 for( uint i = 0; i < max; ++i ) {
334 Node *m = n->in(i);
335 if (not_a_node(m)) continue;
336 useful.push(m);
337 }
338 }
339 }
340
341 // Update dead_node_list with any missing dead nodes using useful
342 // list. Consider all non-useful nodes to be useless i.e., dead nodes.
343 void Compile::update_dead_node_list(Unique_Node_List &useful) {
344 uint max_idx = unique();
345 VectorSet& useful_node_set = useful.member_set();
346
347 for (uint node_idx = 0; node_idx < max_idx; node_idx++) {
348 // If node with index node_idx is not in useful set,
349 // mark it as dead in dead node list.
350 if (! useful_node_set.test(node_idx) ) {
351 record_dead_node(node_idx);
352 }
353 }
354 }
355
356 void Compile::remove_useless_late_inlines(GrowableArray<CallGenerator*>* inlines, Unique_Node_List &useful) {
357 int shift = 0;
358 for (int i = 0; i < inlines->length(); i++) {
359 CallGenerator* cg = inlines->at(i);
360 CallNode* call = cg->call_node();
361 if (shift > 0) {
362 inlines->at_put(i-shift, cg);
363 }
364 if (!useful.member(call)) {
365 shift++;
366 }
367 }
368 inlines->trunc_to(inlines->length()-shift);
369 }
370
371 // Disconnect all useless nodes by disconnecting those at the boundary.
372 void Compile::remove_useless_nodes(Unique_Node_List &useful) {
373 uint next = 0;
374 while (next < useful.size()) {
375 Node *n = useful.at(next++);
376 if (n->is_SafePoint()) {
377 // We're done with a parsing phase. Replaced nodes are not valid
378 // beyond that point.
379 n->as_SafePoint()->delete_replaced_nodes();
380 }
381 // Use raw traversal of out edges since this code removes out edges
382 int max = n->outcnt();
383 for (int j = 0; j < max; ++j) {
384 Node* child = n->raw_out(j);
385 if (! useful.member(child)) {
386 assert(!child->is_top() || child != top(),
387 "If top is cached in Compile object it is in useful list");
388 // Only need to remove this out-edge to the useless node
389 n->raw_del_out(j);
390 --j;
391 --max;
392 }
393 }
394 if (n->outcnt() == 1 && n->has_special_unique_user()) {
395 record_for_igvn(n->unique_out());
396 }
397 }
398 // Remove useless macro and predicate opaq nodes
399 for (int i = C->macro_count()-1; i >= 0; i--) {
400 Node* n = C->macro_node(i);
401 if (!useful.member(n)) {
402 remove_macro_node(n);
403 }
404 }
405 // Remove useless expensive node
406 for (int i = C->expensive_count()-1; i >= 0; i--) {
407 Node* n = C->expensive_node(i);
408 if (!useful.member(n)) {
409 remove_expensive_node(n);
410 }
411 }
412 // clean up the late inline lists
413 remove_useless_late_inlines(&_string_late_inlines, useful);
414 remove_useless_late_inlines(&_boxing_late_inlines, useful);
415 remove_useless_late_inlines(&_late_inlines, useful);
416 debug_only(verify_graph_edges(true/*check for no_dead_code*/);)
417 }
418
419 //------------------------------frame_size_in_words-----------------------------
420 // frame_slots in units of words
421 int Compile::frame_size_in_words() const {
422 // shift is 0 in LP32 and 1 in LP64
423 const int shift = (LogBytesPerWord - LogBytesPerInt);
424 int words = _frame_slots >> shift;
425 assert( words << shift == _frame_slots, "frame size must be properly aligned in LP64" );
426 return words;
427 }
428
429 // To bang the stack of this compiled method we use the stack size
430 // that the interpreter would need in case of a deoptimization. This
431 // removes the need to bang the stack in the deoptimization blob which
432 // in turn simplifies stack overflow handling.
433 int Compile::bang_size_in_bytes() const {
434 return MAX2(_interpreter_frame_size, frame_size_in_bytes());
435 }
436
437 // ============================================================================
438 //------------------------------CompileWrapper---------------------------------
439 class CompileWrapper : public StackObj {
440 Compile *const _compile;
441 public:
442 CompileWrapper(Compile* compile);
443
444 ~CompileWrapper();
445 };
446
447 CompileWrapper::CompileWrapper(Compile* compile) : _compile(compile) {
448 // the Compile* pointer is stored in the current ciEnv:
449 ciEnv* env = compile->env();
450 assert(env == ciEnv::current(), "must already be a ciEnv active");
451 assert(env->compiler_data() == NULL, "compile already active?");
452 env->set_compiler_data(compile);
453 assert(compile == Compile::current(), "sanity");
454
455 compile->set_type_dict(NULL);
456 compile->set_type_hwm(NULL);
457 compile->set_type_last_size(0);
458 compile->set_last_tf(NULL, NULL);
459 compile->set_indexSet_arena(NULL);
460 compile->set_indexSet_free_block_list(NULL);
461 compile->init_type_arena();
462 Type::Initialize(compile);
463 _compile->set_scratch_buffer_blob(NULL);
464 _compile->begin_method();
465 }
466 CompileWrapper::~CompileWrapper() {
467 _compile->end_method();
468 if (_compile->scratch_buffer_blob() != NULL)
469 BufferBlob::free(_compile->scratch_buffer_blob());
470 _compile->env()->set_compiler_data(NULL);
471 }
472
473
474 //----------------------------print_compile_messages---------------------------
475 void Compile::print_compile_messages() {
476 #ifndef PRODUCT
477 // Check if recompiling
478 if (_subsume_loads == false && PrintOpto) {
479 // Recompiling without allowing machine instructions to subsume loads
480 tty->print_cr("*********************************************************");
481 tty->print_cr("** Bailout: Recompile without subsuming loads **");
482 tty->print_cr("*********************************************************");
483 }
484 if (_do_escape_analysis != DoEscapeAnalysis && PrintOpto) {
485 // Recompiling without escape analysis
486 tty->print_cr("*********************************************************");
487 tty->print_cr("** Bailout: Recompile without escape analysis **");
488 tty->print_cr("*********************************************************");
489 }
490 if (_eliminate_boxing != EliminateAutoBox && PrintOpto) {
491 // Recompiling without boxing elimination
492 tty->print_cr("*********************************************************");
493 tty->print_cr("** Bailout: Recompile without boxing elimination **");
494 tty->print_cr("*********************************************************");
495 }
496 if (env()->break_at_compile()) {
497 // Open the debugger when compiling this method.
498 tty->print("### Breaking when compiling: ");
499 method()->print_short_name();
500 tty->cr();
501 BREAKPOINT;
502 }
503
504 if( PrintOpto ) {
505 if (is_osr_compilation()) {
506 tty->print("[OSR]%3d", _compile_id);
507 } else {
508 tty->print("%3d", _compile_id);
509 }
510 }
511 #endif
512 }
513
514
515 //-----------------------init_scratch_buffer_blob------------------------------
516 // Construct a temporary BufferBlob and cache it for this compile.
517 void Compile::init_scratch_buffer_blob(int const_size) {
518 // If there is already a scratch buffer blob allocated and the
519 // constant section is big enough, use it. Otherwise free the
520 // current and allocate a new one.
521 BufferBlob* blob = scratch_buffer_blob();
522 if ((blob != NULL) && (const_size <= _scratch_const_size)) {
523 // Use the current blob.
524 } else {
525 if (blob != NULL) {
526 BufferBlob::free(blob);
527 }
528
529 ResourceMark rm;
530 _scratch_const_size = const_size;
531 int size = (MAX_inst_size + MAX_stubs_size + _scratch_const_size);
532 blob = BufferBlob::create("Compile::scratch_buffer", size);
533 // Record the buffer blob for next time.
534 set_scratch_buffer_blob(blob);
535 // Have we run out of code space?
536 if (scratch_buffer_blob() == NULL) {
537 // Let CompilerBroker disable further compilations.
538 record_failure("Not enough space for scratch buffer in CodeCache");
539 CompileBroker::handle_full_code_cache();
540 return;
541 }
542 }
543
544 // Initialize the relocation buffers
545 relocInfo* locs_buf = (relocInfo*) blob->content_end() - MAX_locs_size;
546 set_scratch_locs_memory(locs_buf);
547 }
548
549
550 //-----------------------scratch_emit_size-------------------------------------
551 // Helper function that computes size by emitting code
552 uint Compile::scratch_emit_size(const Node* n) {
553 // Start scratch_emit_size section.
554 set_in_scratch_emit_size(true);
555
556 // Emit into a trash buffer and count bytes emitted.
557 // This is a pretty expensive way to compute a size,
558 // but it works well enough if seldom used.
559 // All common fixed-size instructions are given a size
560 // method by the AD file.
561 // Note that the scratch buffer blob and locs memory are
562 // allocated at the beginning of the compile task, and
563 // may be shared by several calls to scratch_emit_size.
564 // The allocation of the scratch buffer blob is particularly
565 // expensive, since it has to grab the code cache lock.
566 BufferBlob* blob = this->scratch_buffer_blob();
567 assert(blob != NULL, "Initialize BufferBlob at start");
568 assert(blob->size() > MAX_inst_size, "sanity");
569 relocInfo* locs_buf = scratch_locs_memory();
570 address blob_begin = blob->content_begin();
571 address blob_end = (address)locs_buf;
572 assert(blob->content_contains(blob_end), "sanity");
573 CodeBuffer buf(blob_begin, blob_end - blob_begin);
574 buf.initialize_consts_size(_scratch_const_size);
575 buf.initialize_stubs_size(MAX_stubs_size);
576 assert(locs_buf != NULL, "sanity");
577 int lsize = MAX_locs_size / 3;
578 buf.consts()->initialize_shared_locs(&locs_buf[lsize * 0], lsize);
579 buf.insts()->initialize_shared_locs( &locs_buf[lsize * 1], lsize);
580 buf.stubs()->initialize_shared_locs( &locs_buf[lsize * 2], lsize);
581
582 // Do the emission.
583
584 Label fakeL; // Fake label for branch instructions.
585 Label* saveL = NULL;
586 uint save_bnum = 0;
587 bool is_branch = n->is_MachBranch();
588 if (is_branch) {
589 MacroAssembler masm(&buf);
590 masm.bind(fakeL);
591 n->as_MachBranch()->save_label(&saveL, &save_bnum);
592 n->as_MachBranch()->label_set(&fakeL, 0);
593 }
594 n->emit(buf, this->regalloc());
595 if (is_branch) // Restore label.
596 n->as_MachBranch()->label_set(saveL, save_bnum);
597
598 // End scratch_emit_size section.
599 set_in_scratch_emit_size(false);
600
601 return buf.insts_size();
602 }
603
604
605 // ============================================================================
606 //------------------------------Compile standard-------------------------------
607 debug_only( int Compile::_debug_idx = 100000; )
608
609 // Compile a method. entry_bci is -1 for normal compilations and indicates
610 // the continuation bci for on stack replacement.
611
612
613 Compile::Compile( ciEnv* ci_env, C2Compiler* compiler, ciMethod* target, int osr_bci,
614 bool subsume_loads, bool do_escape_analysis, bool eliminate_boxing )
615 : Phase(Compiler),
616 _env(ci_env),
617 _log(ci_env->log()),
618 _compile_id(ci_env->compile_id()),
619 _save_argument_registers(false),
620 _stub_name(NULL),
621 _stub_function(NULL),
622 _stub_entry_point(NULL),
623 _method(target),
624 _entry_bci(osr_bci),
625 _initial_gvn(NULL),
626 _for_igvn(NULL),
627 _warm_calls(NULL),
628 _subsume_loads(subsume_loads),
629 _do_escape_analysis(do_escape_analysis),
630 _eliminate_boxing(eliminate_boxing),
631 _failure_reason(NULL),
632 _code_buffer("Compile::Fill_buffer"),
633 _orig_pc_slot(0),
634 _orig_pc_slot_offset_in_bytes(0),
635 _has_method_handle_invokes(false),
636 _mach_constant_base_node(NULL),
637 _node_bundling_limit(0),
638 _node_bundling_base(NULL),
639 _java_calls(0),
640 _inner_loops(0),
641 _scratch_const_size(-1),
642 _in_scratch_emit_size(false),
643 _dead_node_list(comp_arena()),
644 _dead_node_count(0),
645 #ifndef PRODUCT
646 _trace_opto_output(TraceOptoOutput || method()->has_option("TraceOptoOutput")),
647 _in_dump_cnt(0),
648 _printer(IdealGraphPrinter::printer()),
649 #endif
650 _congraph(NULL),
651 _replay_inline_data(NULL),
652 _late_inlines(comp_arena(), 2, 0, NULL),
653 _string_late_inlines(comp_arena(), 2, 0, NULL),
654 _boxing_late_inlines(comp_arena(), 2, 0, NULL),
655 _late_inlines_pos(0),
656 _number_of_mh_late_inlines(0),
657 _inlining_progress(false),
658 _inlining_incrementally(false),
659 _print_inlining_list(NULL),
660 _print_inlining_stream(NULL),
661 _print_inlining_idx(0),
662 _print_inlining_output(NULL),
663 _interpreter_frame_size(0) {
664 C = this;
665
666 CompileWrapper cw(this);
667 #ifndef PRODUCT
668 if (TimeCompiler2) {
669 tty->print(" ");
670 target->holder()->name()->print();
671 tty->print(".");
672 target->print_short_name();
673 tty->print(" ");
674 }
675 TraceTime t1("Total compilation time", &_t_totalCompilation, TimeCompiler, TimeCompiler2);
676 TraceTime t2(NULL, &_t_methodCompilation, TimeCompiler, false);
677 bool print_opto_assembly = PrintOptoAssembly || _method->has_option("PrintOptoAssembly");
678 if (!print_opto_assembly) {
679 bool print_assembly = (PrintAssembly || _method->should_print_assembly());
680 if (print_assembly && !Disassembler::can_decode()) {
681 tty->print_cr("PrintAssembly request changed to PrintOptoAssembly");
682 print_opto_assembly = true;
683 }
684 }
685 set_print_assembly(print_opto_assembly);
686 set_parsed_irreducible_loop(false);
687
688 if (method()->has_option("ReplayInline")) {
689 _replay_inline_data = ciReplay::load_inline_data(method(), entry_bci(), ci_env->comp_level());
690 }
691 #endif
692 set_print_inlining(PrintInlining || method()->has_option("PrintInlining") NOT_PRODUCT( || PrintOptoInlining));
693 set_print_intrinsics(PrintIntrinsics || method()->has_option("PrintIntrinsics"));
694 set_has_irreducible_loop(true); // conservative until build_loop_tree() reset it
695
696 if (ProfileTraps RTM_OPT_ONLY( || UseRTMLocking )) {
697 // Make sure the method being compiled gets its own MDO,
698 // so we can at least track the decompile_count().
699 // Need MDO to record RTM code generation state.
700 method()->ensure_method_data();
701 }
702
703 Init(::AliasLevel);
704
705
706 print_compile_messages();
707
708 _ilt = InlineTree::build_inline_tree_root();
709
710 // Even if NO memory addresses are used, MergeMem nodes must have at least 1 slice
711 assert(num_alias_types() >= AliasIdxRaw, "");
712
713 #define MINIMUM_NODE_HASH 1023
714 // Node list that Iterative GVN will start with
715 Unique_Node_List for_igvn(comp_arena());
716 set_for_igvn(&for_igvn);
717
718 // GVN that will be run immediately on new nodes
719 uint estimated_size = method()->code_size()*4+64;
720 estimated_size = (estimated_size < MINIMUM_NODE_HASH ? MINIMUM_NODE_HASH : estimated_size);
721 PhaseGVN gvn(node_arena(), estimated_size);
722 set_initial_gvn(&gvn);
723
724 print_inlining_init();
725 { // Scope for timing the parser
726 TracePhase t3("parse", &_t_parser, true);
727
728 // Put top into the hash table ASAP.
729 initial_gvn()->transform_no_reclaim(top());
730
731 // Set up tf(), start(), and find a CallGenerator.
732 CallGenerator* cg = NULL;
733 if (is_osr_compilation()) {
734 const TypeTuple *domain = StartOSRNode::osr_domain();
735 const TypeTuple *range = TypeTuple::make_range(method()->signature());
736 init_tf(TypeFunc::make(domain, range));
737 StartNode* s = new StartOSRNode(root(), domain);
738 initial_gvn()->set_type_bottom(s);
739 init_start(s);
740 cg = CallGenerator::for_osr(method(), entry_bci());
741 } else {
742 // Normal case.
743 init_tf(TypeFunc::make(method()));
744 StartNode* s = new StartNode(root(), tf()->domain());
745 initial_gvn()->set_type_bottom(s);
746 init_start(s);
747 if (method()->intrinsic_id() == vmIntrinsics::_Reference_get && UseG1GC) {
748 // With java.lang.ref.reference.get() we must go through the
749 // intrinsic when G1 is enabled - even when get() is the root
750 // method of the compile - so that, if necessary, the value in
751 // the referent field of the reference object gets recorded by
752 // the pre-barrier code.
753 // Specifically, if G1 is enabled, the value in the referent
754 // field is recorded by the G1 SATB pre barrier. This will
755 // result in the referent being marked live and the reference
756 // object removed from the list of discovered references during
757 // reference processing.
758 cg = find_intrinsic(method(), false);
759 }
760 if (cg == NULL) {
761 float past_uses = method()->interpreter_invocation_count();
762 float expected_uses = past_uses;
763 cg = CallGenerator::for_inline(method(), expected_uses);
764 }
765 }
766 if (failing()) return;
767 if (cg == NULL) {
768 record_method_not_compilable_all_tiers("cannot parse method");
769 return;
770 }
771 JVMState* jvms = build_start_state(start(), tf());
772 if ((jvms = cg->generate(jvms)) == NULL) {
773 record_method_not_compilable("method parse failed");
774 return;
775 }
776 GraphKit kit(jvms);
777
778 if (!kit.stopped()) {
779 // Accept return values, and transfer control we know not where.
780 // This is done by a special, unique ReturnNode bound to root.
781 return_values(kit.jvms());
782 }
783
784 if (kit.has_exceptions()) {
785 // Any exceptions that escape from this call must be rethrown
786 // to whatever caller is dynamically above us on the stack.
787 // This is done by a special, unique RethrowNode bound to root.
788 rethrow_exceptions(kit.transfer_exceptions_into_jvms());
789 }
790
791 assert(IncrementalInline || (_late_inlines.length() == 0 && !has_mh_late_inlines()), "incremental inlining is off");
792
793 if (_late_inlines.length() == 0 && !has_mh_late_inlines() && !failing() && has_stringbuilder()) {
794 inline_string_calls(true);
795 }
796
797 if (failing()) return;
798
799 print_method(PHASE_BEFORE_REMOVEUSELESS, 3);
800
801 // Remove clutter produced by parsing.
802 if (!failing()) {
803 ResourceMark rm;
804 PhaseRemoveUseless pru(initial_gvn(), &for_igvn);
805 }
806 }
807
808 // Note: Large methods are capped off in do_one_bytecode().
809 if (failing()) return;
810
811 // After parsing, node notes are no longer automagic.
812 // They must be propagated by register_new_node_with_optimizer(),
813 // clone(), or the like.
814 set_default_node_notes(NULL);
815
816 for (;;) {
817 int successes = Inline_Warm();
818 if (failing()) return;
819 if (successes == 0) break;
820 }
821
822 // Drain the list.
823 Finish_Warm();
824 #ifndef PRODUCT
825 if (_printer) {
826 _printer->print_inlining(this);
827 }
828 #endif
829
830 if (failing()) return;
831 NOT_PRODUCT( verify_graph_edges(); )
832
833 // Now optimize
834 Optimize();
835 if (failing()) return;
836 NOT_PRODUCT( verify_graph_edges(); )
837
838 #ifndef PRODUCT
839 if (PrintIdeal) {
840 ttyLocker ttyl; // keep the following output all in one block
841 // This output goes directly to the tty, not the compiler log.
842 // To enable tools to match it up with the compilation activity,
843 // be sure to tag this tty output with the compile ID.
844 if (xtty != NULL) {
845 xtty->head("ideal compile_id='%d'%s", compile_id(),
846 is_osr_compilation() ? " compile_kind='osr'" :
847 "");
848 }
849 root()->dump(9999);
850 if (xtty != NULL) {
851 xtty->tail("ideal");
852 }
853 }
854 #endif
855
856 NOT_PRODUCT( verify_barriers(); )
857
858 // Dump compilation data to replay it.
859 if (method()->has_option("DumpReplay")) {
860 env()->dump_replay_data(_compile_id);
861 }
862 if (method()->has_option("DumpInline") && (ilt() != NULL)) {
863 env()->dump_inline_data(_compile_id);
864 }
865
866 // Now that we know the size of all the monitors we can add a fixed slot
867 // for the original deopt pc.
868
869 _orig_pc_slot = fixed_slots();
870 int next_slot = _orig_pc_slot + (sizeof(address) / VMRegImpl::stack_slot_size);
871 set_fixed_slots(next_slot);
872
873 // Compute when to use implicit null checks. Used by matching trap based
874 // nodes and NullCheck optimization.
875 set_allowed_deopt_reasons();
876
877 // Now generate code
878 Code_Gen();
879 if (failing()) return;
880
881 // Check if we want to skip execution of all compiled code.
882 {
883 #ifndef PRODUCT
884 if (OptoNoExecute) {
885 record_method_not_compilable("+OptoNoExecute"); // Flag as failed
886 return;
887 }
888 TracePhase t2("install_code", &_t_registerMethod, TimeCompiler);
889 #endif
890
891 if (is_osr_compilation()) {
892 _code_offsets.set_value(CodeOffsets::Verified_Entry, 0);
893 _code_offsets.set_value(CodeOffsets::OSR_Entry, _first_block_size);
894 } else {
895 _code_offsets.set_value(CodeOffsets::Verified_Entry, _first_block_size);
896 _code_offsets.set_value(CodeOffsets::OSR_Entry, 0);
897 }
898
899 env()->register_method(_method, _entry_bci,
900 &_code_offsets,
901 _orig_pc_slot_offset_in_bytes,
902 code_buffer(),
903 frame_size_in_words(), _oop_map_set,
904 &_handler_table, &_inc_table,
905 compiler,
906 env()->comp_level(),
907 has_unsafe_access(),
908 SharedRuntime::is_wide_vector(max_vector_size()),
909 rtm_state()
910 );
911
912 if (log() != NULL) // Print code cache state into compiler log
913 log()->code_cache_state();
914 }
915 }
916
917 //------------------------------Compile----------------------------------------
918 // Compile a runtime stub
919 Compile::Compile( ciEnv* ci_env,
920 TypeFunc_generator generator,
921 address stub_function,
922 const char *stub_name,
923 int is_fancy_jump,
924 bool pass_tls,
925 bool save_arg_registers,
926 bool return_pc )
927 : Phase(Compiler),
928 _env(ci_env),
929 _log(ci_env->log()),
930 _compile_id(0),
931 _save_argument_registers(save_arg_registers),
932 _method(NULL),
933 _stub_name(stub_name),
934 _stub_function(stub_function),
935 _stub_entry_point(NULL),
936 _entry_bci(InvocationEntryBci),
937 _initial_gvn(NULL),
938 _for_igvn(NULL),
939 _warm_calls(NULL),
940 _orig_pc_slot(0),
941 _orig_pc_slot_offset_in_bytes(0),
942 _subsume_loads(true),
943 _do_escape_analysis(false),
944 _eliminate_boxing(false),
945 _failure_reason(NULL),
946 _code_buffer("Compile::Fill_buffer"),
947 _has_method_handle_invokes(false),
948 _mach_constant_base_node(NULL),
949 _node_bundling_limit(0),
950 _node_bundling_base(NULL),
951 _java_calls(0),
952 _inner_loops(0),
953 #ifndef PRODUCT
954 _trace_opto_output(TraceOptoOutput),
955 _in_dump_cnt(0),
956 _printer(NULL),
957 #endif
958 _dead_node_list(comp_arena()),
959 _dead_node_count(0),
960 _congraph(NULL),
961 _replay_inline_data(NULL),
962 _number_of_mh_late_inlines(0),
963 _inlining_progress(false),
964 _inlining_incrementally(false),
965 _print_inlining_list(NULL),
966 _print_inlining_stream(NULL),
967 _print_inlining_idx(0),
968 _print_inlining_output(NULL),
969 _allowed_reasons(0),
970 _interpreter_frame_size(0) {
971 C = this;
972
973 #ifndef PRODUCT
974 TraceTime t1(NULL, &_t_totalCompilation, TimeCompiler, false);
975 TraceTime t2(NULL, &_t_stubCompilation, TimeCompiler, false);
976 set_print_assembly(PrintFrameConverterAssembly);
977 set_parsed_irreducible_loop(false);
978 #endif
979 set_has_irreducible_loop(false); // no loops
980
981 CompileWrapper cw(this);
982 Init(/*AliasLevel=*/ 0);
983 init_tf((*generator)());
984
985 {
986 // The following is a dummy for the sake of GraphKit::gen_stub
987 Unique_Node_List for_igvn(comp_arena());
988 set_for_igvn(&for_igvn); // not used, but some GraphKit guys push on this
989 PhaseGVN gvn(Thread::current()->resource_area(),255);
990 set_initial_gvn(&gvn); // not significant, but GraphKit guys use it pervasively
991 gvn.transform_no_reclaim(top());
992
993 GraphKit kit;
994 kit.gen_stub(stub_function, stub_name, is_fancy_jump, pass_tls, return_pc);
995 }
996
997 NOT_PRODUCT( verify_graph_edges(); )
998 Code_Gen();
999 if (failing()) return;
1000
1001
1002 // Entry point will be accessed using compile->stub_entry_point();
1003 if (code_buffer() == NULL) {
1004 Matcher::soft_match_failure();
1005 } else {
1006 if (PrintAssembly && (WizardMode || Verbose))
1007 tty->print_cr("### Stub::%s", stub_name);
1008
1009 if (!failing()) {
1010 assert(_fixed_slots == 0, "no fixed slots used for runtime stubs");
1011
1012 // Make the NMethod
1013 // For now we mark the frame as never safe for profile stackwalking
1014 RuntimeStub *rs = RuntimeStub::new_runtime_stub(stub_name,
1015 code_buffer(),
1016 CodeOffsets::frame_never_safe,
1017 // _code_offsets.value(CodeOffsets::Frame_Complete),
1018 frame_size_in_words(),
1019 _oop_map_set,
1020 save_arg_registers);
1021 assert(rs != NULL && rs->is_runtime_stub(), "sanity check");
1022
1023 _stub_entry_point = rs->entry_point();
1024 }
1025 }
1026 }
1027
1028 //------------------------------Init-------------------------------------------
1029 // Prepare for a single compilation
1030 void Compile::Init(int aliaslevel) {
1031 _unique = 0;
1032 _regalloc = NULL;
1033
1034 _tf = NULL; // filled in later
1035 _top = NULL; // cached later
1036 _matcher = NULL; // filled in later
1037 _cfg = NULL; // filled in later
1038
1039 set_24_bit_selection_and_mode(Use24BitFP, false);
1040
1041 _node_note_array = NULL;
1042 _default_node_notes = NULL;
1043
1044 _immutable_memory = NULL; // filled in at first inquiry
1045
1046 // Globally visible Nodes
1047 // First set TOP to NULL to give safe behavior during creation of RootNode
1048 set_cached_top_node(NULL);
1049 set_root(new RootNode());
1050 // Now that you have a Root to point to, create the real TOP
1051 set_cached_top_node( new ConNode(Type::TOP) );
1052 set_recent_alloc(NULL, NULL);
1053
1054 // Create Debug Information Recorder to record scopes, oopmaps, etc.
1055 env()->set_oop_recorder(new OopRecorder(env()->arena()));
1056 env()->set_debug_info(new DebugInformationRecorder(env()->oop_recorder()));
1057 env()->set_dependencies(new Dependencies(env()));
1058
1059 _fixed_slots = 0;
1060 set_has_split_ifs(false);
1061 set_has_loops(has_method() && method()->has_loops()); // first approximation
1062 set_has_stringbuilder(false);
1063 set_has_boxed_value(false);
1064 _trap_can_recompile = false; // no traps emitted yet
1065 _major_progress = true; // start out assuming good things will happen
1066 set_has_unsafe_access(false);
1067 set_max_vector_size(0);
1068 Copy::zero_to_bytes(_trap_hist, sizeof(_trap_hist));
1069 set_decompile_count(0);
1070
1071 set_do_freq_based_layout(BlockLayoutByFrequency || method_has_option("BlockLayoutByFrequency"));
1072 set_num_loop_opts(LoopOptsCount);
1073 set_do_inlining(Inline);
1074 set_max_inline_size(MaxInlineSize);
1075 set_freq_inline_size(FreqInlineSize);
1076 set_do_scheduling(OptoScheduling);
1077 set_do_count_invocations(false);
1078 set_do_method_data_update(false);
1079 set_age_code(has_method() && method()->profile_aging());
1080 set_rtm_state(NoRTM); // No RTM lock eliding by default
1081 #if INCLUDE_RTM_OPT
1082 if (UseRTMLocking && has_method() && (method()->method_data_or_null() != NULL)) {
1083 int rtm_state = method()->method_data()->rtm_state();
1084 if (method_has_option("NoRTMLockEliding") || ((rtm_state & NoRTM) != 0)) {
1085 // Don't generate RTM lock eliding code.
1086 set_rtm_state(NoRTM);
1087 } else if (method_has_option("UseRTMLockEliding") || ((rtm_state & UseRTM) != 0) || !UseRTMDeopt) {
1088 // Generate RTM lock eliding code without abort ratio calculation code.
1089 set_rtm_state(UseRTM);
1090 } else if (UseRTMDeopt) {
1091 // Generate RTM lock eliding code and include abort ratio calculation
1092 // code if UseRTMDeopt is on.
1093 set_rtm_state(ProfileRTM);
1094 }
1095 }
1096 #endif
1097 if (debug_info()->recording_non_safepoints()) {
1098 set_node_note_array(new(comp_arena()) GrowableArray<Node_Notes*>
1099 (comp_arena(), 8, 0, NULL));
1100 set_default_node_notes(Node_Notes::make(this));
1101 }
1102
1103 // // -- Initialize types before each compile --
1104 // // Update cached type information
1105 // if( _method && _method->constants() )
1106 // Type::update_loaded_types(_method, _method->constants());
1107
1108 // Init alias_type map.
1109 if (!_do_escape_analysis && aliaslevel == 3)
1110 aliaslevel = 2; // No unique types without escape analysis
1111 _AliasLevel = aliaslevel;
1112 const int grow_ats = 16;
1113 _max_alias_types = grow_ats;
1114 _alias_types = NEW_ARENA_ARRAY(comp_arena(), AliasType*, grow_ats);
1115 AliasType* ats = NEW_ARENA_ARRAY(comp_arena(), AliasType, grow_ats);
1116 Copy::zero_to_bytes(ats, sizeof(AliasType)*grow_ats);
1117 {
1118 for (int i = 0; i < grow_ats; i++) _alias_types[i] = &ats[i];
1119 }
1120 // Initialize the first few types.
1121 _alias_types[AliasIdxTop]->Init(AliasIdxTop, NULL);
1122 _alias_types[AliasIdxBot]->Init(AliasIdxBot, TypePtr::BOTTOM);
1123 _alias_types[AliasIdxRaw]->Init(AliasIdxRaw, TypeRawPtr::BOTTOM);
1124 _num_alias_types = AliasIdxRaw+1;
1125 // Zero out the alias type cache.
1126 Copy::zero_to_bytes(_alias_cache, sizeof(_alias_cache));
1127 // A NULL adr_type hits in the cache right away. Preload the right answer.
1128 probe_alias_cache(NULL)->_index = AliasIdxTop;
1129
1130 _intrinsics = NULL;
1131 _macro_nodes = new(comp_arena()) GrowableArray<Node*>(comp_arena(), 8, 0, NULL);
1132 _predicate_opaqs = new(comp_arena()) GrowableArray<Node*>(comp_arena(), 8, 0, NULL);
1133 _expensive_nodes = new(comp_arena()) GrowableArray<Node*>(comp_arena(), 8, 0, NULL);
1134 register_library_intrinsics();
1135 }
1136
1137 //---------------------------init_start----------------------------------------
1138 // Install the StartNode on this compile object.
1139 void Compile::init_start(StartNode* s) {
1140 if (failing())
1141 return; // already failing
1142 assert(s == start(), "");
1143 }
1144
1145 StartNode* Compile::start() const {
1146 assert(!failing(), "");
1147 for (DUIterator_Fast imax, i = root()->fast_outs(imax); i < imax; i++) {
1148 Node* start = root()->fast_out(i);
1149 if( start->is_Start() )
1150 return start->as_Start();
1151 }
1152 fatal("Did not find Start node!");
1153 return NULL;
1154 }
1155
1156 //-------------------------------immutable_memory-------------------------------------
1157 // Access immutable memory
1158 Node* Compile::immutable_memory() {
1159 if (_immutable_memory != NULL) {
1160 return _immutable_memory;
1161 }
1162 StartNode* s = start();
1163 for (DUIterator_Fast imax, i = s->fast_outs(imax); true; i++) {
1164 Node *p = s->fast_out(i);
1165 if (p != s && p->as_Proj()->_con == TypeFunc::Memory) {
1166 _immutable_memory = p;
1167 return _immutable_memory;
1168 }
1169 }
1170 ShouldNotReachHere();
1171 return NULL;
1172 }
1173
1174 //----------------------set_cached_top_node------------------------------------
1175 // Install the cached top node, and make sure Node::is_top works correctly.
1176 void Compile::set_cached_top_node(Node* tn) {
1177 if (tn != NULL) verify_top(tn);
1178 Node* old_top = _top;
1179 _top = tn;
1180 // Calling Node::setup_is_top allows the nodes the chance to adjust
1181 // their _out arrays.
1182 if (_top != NULL) _top->setup_is_top();
1183 if (old_top != NULL) old_top->setup_is_top();
1184 assert(_top == NULL || top()->is_top(), "");
1185 }
1186
1187 #ifdef ASSERT
1188 uint Compile::count_live_nodes_by_graph_walk() {
1189 Unique_Node_List useful(comp_arena());
1190 // Get useful node list by walking the graph.
1191 identify_useful_nodes(useful);
1192 return useful.size();
1193 }
1194
1195 void Compile::print_missing_nodes() {
1196
1197 // Return if CompileLog is NULL and PrintIdealNodeCount is false.
1198 if ((_log == NULL) && (! PrintIdealNodeCount)) {
1199 return;
1200 }
1201
1202 // This is an expensive function. It is executed only when the user
1203 // specifies VerifyIdealNodeCount option or otherwise knows the
1204 // additional work that needs to be done to identify reachable nodes
1205 // by walking the flow graph and find the missing ones using
1206 // _dead_node_list.
1207
1208 Unique_Node_List useful(comp_arena());
1209 // Get useful node list by walking the graph.
1210 identify_useful_nodes(useful);
1211
1212 uint l_nodes = C->live_nodes();
1213 uint l_nodes_by_walk = useful.size();
1214
1215 if (l_nodes != l_nodes_by_walk) {
1216 if (_log != NULL) {
1217 _log->begin_head("mismatched_nodes count='%d'", abs((int) (l_nodes - l_nodes_by_walk)));
1218 _log->stamp();
1219 _log->end_head();
1220 }
1221 VectorSet& useful_member_set = useful.member_set();
1222 int last_idx = l_nodes_by_walk;
1223 for (int i = 0; i < last_idx; i++) {
1224 if (useful_member_set.test(i)) {
1225 if (_dead_node_list.test(i)) {
1226 if (_log != NULL) {
1227 _log->elem("mismatched_node_info node_idx='%d' type='both live and dead'", i);
1228 }
1229 if (PrintIdealNodeCount) {
1230 // Print the log message to tty
1231 tty->print_cr("mismatched_node idx='%d' both live and dead'", i);
1232 useful.at(i)->dump();
1233 }
1234 }
1235 }
1236 else if (! _dead_node_list.test(i)) {
1237 if (_log != NULL) {
1238 _log->elem("mismatched_node_info node_idx='%d' type='neither live nor dead'", i);
1239 }
1240 if (PrintIdealNodeCount) {
1241 // Print the log message to tty
1242 tty->print_cr("mismatched_node idx='%d' type='neither live nor dead'", i);
1243 }
1244 }
1245 }
1246 if (_log != NULL) {
1247 _log->tail("mismatched_nodes");
1248 }
1249 }
1250 }
1251 #endif
1252
1253 #ifndef PRODUCT
1254 void Compile::verify_top(Node* tn) const {
1255 if (tn != NULL) {
1256 assert(tn->is_Con(), "top node must be a constant");
1257 assert(((ConNode*)tn)->type() == Type::TOP, "top node must have correct type");
1258 assert(tn->in(0) != NULL, "must have live top node");
1259 }
1260 }
1261 #endif
1262
1263
1264 ///-------------------Managing Per-Node Debug & Profile Info-------------------
1265
1266 void Compile::grow_node_notes(GrowableArray<Node_Notes*>* arr, int grow_by) {
1267 guarantee(arr != NULL, "");
1268 int num_blocks = arr->length();
1269 if (grow_by < num_blocks) grow_by = num_blocks;
1270 int num_notes = grow_by * _node_notes_block_size;
1271 Node_Notes* notes = NEW_ARENA_ARRAY(node_arena(), Node_Notes, num_notes);
1272 Copy::zero_to_bytes(notes, num_notes * sizeof(Node_Notes));
1273 while (num_notes > 0) {
1274 arr->append(notes);
1275 notes += _node_notes_block_size;
1276 num_notes -= _node_notes_block_size;
1277 }
1278 assert(num_notes == 0, "exact multiple, please");
1279 }
1280
1281 bool Compile::copy_node_notes_to(Node* dest, Node* source) {
1282 if (source == NULL || dest == NULL) return false;
1283
1284 if (dest->is_Con())
1285 return false; // Do not push debug info onto constants.
1286
1287 #ifdef ASSERT
1288 // Leave a bread crumb trail pointing to the original node:
1289 if (dest != NULL && dest != source && dest->debug_orig() == NULL) {
1290 dest->set_debug_orig(source);
1291 }
1292 #endif
1293
1294 if (node_note_array() == NULL)
1295 return false; // Not collecting any notes now.
1296
1297 // This is a copy onto a pre-existing node, which may already have notes.
1298 // If both nodes have notes, do not overwrite any pre-existing notes.
1299 Node_Notes* source_notes = node_notes_at(source->_idx);
1300 if (source_notes == NULL || source_notes->is_clear()) return false;
1301 Node_Notes* dest_notes = node_notes_at(dest->_idx);
1302 if (dest_notes == NULL || dest_notes->is_clear()) {
1303 return set_node_notes_at(dest->_idx, source_notes);
1304 }
1305
1306 Node_Notes merged_notes = (*source_notes);
1307 // The order of operations here ensures that dest notes will win...
1308 merged_notes.update_from(dest_notes);
1309 return set_node_notes_at(dest->_idx, &merged_notes);
1310 }
1311
1312
1313 //--------------------------allow_range_check_smearing-------------------------
1314 // Gating condition for coalescing similar range checks.
1315 // Sometimes we try 'speculatively' replacing a series of a range checks by a
1316 // single covering check that is at least as strong as any of them.
1317 // If the optimization succeeds, the simplified (strengthened) range check
1318 // will always succeed. If it fails, we will deopt, and then give up
1319 // on the optimization.
1320 bool Compile::allow_range_check_smearing() const {
1321 // If this method has already thrown a range-check,
1322 // assume it was because we already tried range smearing
1323 // and it failed.
1324 uint already_trapped = trap_count(Deoptimization::Reason_range_check);
1325 return !already_trapped;
1326 }
1327
1328
1329 //------------------------------flatten_alias_type-----------------------------
1330 const TypePtr *Compile::flatten_alias_type( const TypePtr *tj ) const {
1331 int offset = tj->offset();
1332 TypePtr::PTR ptr = tj->ptr();
1333
1334 // Known instance (scalarizable allocation) alias only with itself.
1335 bool is_known_inst = tj->isa_oopptr() != NULL &&
1336 tj->is_oopptr()->is_known_instance();
1337
1338 // Process weird unsafe references.
1339 if (offset == Type::OffsetBot && (tj->isa_instptr() /*|| tj->isa_klassptr()*/)) {
1340 assert(InlineUnsafeOps, "indeterminate pointers come only from unsafe ops");
1341 assert(!is_known_inst, "scalarizable allocation should not have unsafe references");
1342 tj = TypeOopPtr::BOTTOM;
1343 ptr = tj->ptr();
1344 offset = tj->offset();
1345 }
1346
1347 // Array pointers need some flattening
1348 const TypeAryPtr *ta = tj->isa_aryptr();
1349 if (ta && ta->is_stable()) {
1350 // Erase stability property for alias analysis.
1351 tj = ta = ta->cast_to_stable(false);
1352 }
1353 if( ta && is_known_inst ) {
1354 if ( offset != Type::OffsetBot &&
1355 offset > arrayOopDesc::length_offset_in_bytes() ) {
1356 offset = Type::OffsetBot; // Flatten constant access into array body only
1357 tj = ta = TypeAryPtr::make(ptr, ta->ary(), ta->klass(), true, offset, ta->instance_id());
1358 }
1359 } else if( ta && _AliasLevel >= 2 ) {
1360 // For arrays indexed by constant indices, we flatten the alias
1361 // space to include all of the array body. Only the header, klass
1362 // and array length can be accessed un-aliased.
1363 if( offset != Type::OffsetBot ) {
1364 if( ta->const_oop() ) { // MethodData* or Method*
1365 offset = Type::OffsetBot; // Flatten constant access into array body
1366 tj = ta = TypeAryPtr::make(ptr,ta->const_oop(),ta->ary(),ta->klass(),false,offset);
1367 } else if( offset == arrayOopDesc::length_offset_in_bytes() ) {
1368 // range is OK as-is.
1369 tj = ta = TypeAryPtr::RANGE;
1370 } else if( offset == oopDesc::klass_offset_in_bytes() ) {
1371 tj = TypeInstPtr::KLASS; // all klass loads look alike
1372 ta = TypeAryPtr::RANGE; // generic ignored junk
1373 ptr = TypePtr::BotPTR;
1374 } else if( offset == oopDesc::mark_offset_in_bytes() ) {
1375 tj = TypeInstPtr::MARK;
1376 ta = TypeAryPtr::RANGE; // generic ignored junk
1377 ptr = TypePtr::BotPTR;
1378 } else { // Random constant offset into array body
1379 offset = Type::OffsetBot; // Flatten constant access into array body
1380 tj = ta = TypeAryPtr::make(ptr,ta->ary(),ta->klass(),false,offset);
1381 }
1382 }
1383 // Arrays of fixed size alias with arrays of unknown size.
1384 if (ta->size() != TypeInt::POS) {
1385 const TypeAry *tary = TypeAry::make(ta->elem(), TypeInt::POS);
1386 tj = ta = TypeAryPtr::make(ptr,ta->const_oop(),tary,ta->klass(),false,offset);
1387 }
1388 // Arrays of known objects become arrays of unknown objects.
1389 if (ta->elem()->isa_narrowoop() && ta->elem() != TypeNarrowOop::BOTTOM) {
1390 const TypeAry *tary = TypeAry::make(TypeNarrowOop::BOTTOM, ta->size());
1391 tj = ta = TypeAryPtr::make(ptr,ta->const_oop(),tary,NULL,false,offset);
1392 }
1393 if (ta->elem()->isa_oopptr() && ta->elem() != TypeInstPtr::BOTTOM) {
1394 const TypeAry *tary = TypeAry::make(TypeInstPtr::BOTTOM, ta->size());
1395 tj = ta = TypeAryPtr::make(ptr,ta->const_oop(),tary,NULL,false,offset);
1396 }
1397 // Arrays of bytes and of booleans both use 'bastore' and 'baload' so
1398 // cannot be distinguished by bytecode alone.
1399 if (ta->elem() == TypeInt::BOOL) {
1400 const TypeAry *tary = TypeAry::make(TypeInt::BYTE, ta->size());
1401 ciKlass* aklass = ciTypeArrayKlass::make(T_BYTE);
1402 tj = ta = TypeAryPtr::make(ptr,ta->const_oop(),tary,aklass,false,offset);
1403 }
1404 // During the 2nd round of IterGVN, NotNull castings are removed.
1405 // Make sure the Bottom and NotNull variants alias the same.
1406 // Also, make sure exact and non-exact variants alias the same.
1407 if (ptr == TypePtr::NotNull || ta->klass_is_exact() || ta->speculative() != NULL) {
1408 tj = ta = TypeAryPtr::make(TypePtr::BotPTR,ta->ary(),ta->klass(),false,offset);
1409 }
1410 }
1411
1412 // Oop pointers need some flattening
1413 const TypeInstPtr *to = tj->isa_instptr();
1414 if( to && _AliasLevel >= 2 && to != TypeOopPtr::BOTTOM ) {
1415 ciInstanceKlass *k = to->klass()->as_instance_klass();
1416 if( ptr == TypePtr::Constant ) {
1417 if (to->klass() != ciEnv::current()->Class_klass() ||
1418 offset < k->size_helper() * wordSize) {
1419 // No constant oop pointers (such as Strings); they alias with
1420 // unknown strings.
1421 assert(!is_known_inst, "not scalarizable allocation");
1422 tj = to = TypeInstPtr::make(TypePtr::BotPTR,to->klass(),false,0,offset);
1423 }
1424 } else if( is_known_inst ) {
1425 tj = to; // Keep NotNull and klass_is_exact for instance type
1426 } else if( ptr == TypePtr::NotNull || to->klass_is_exact() ) {
1427 // During the 2nd round of IterGVN, NotNull castings are removed.
1428 // Make sure the Bottom and NotNull variants alias the same.
1429 // Also, make sure exact and non-exact variants alias the same.
1430 tj = to = TypeInstPtr::make(TypePtr::BotPTR,to->klass(),false,0,offset);
1431 }
1432 if (to->speculative() != NULL) {
1433 tj = to = TypeInstPtr::make(to->ptr(),to->klass(),to->klass_is_exact(),to->const_oop(),to->offset(), to->instance_id());
1434 }
1435 // Canonicalize the holder of this field
1436 if (offset >= 0 && offset < instanceOopDesc::base_offset_in_bytes()) {
1437 // First handle header references such as a LoadKlassNode, even if the
1438 // object's klass is unloaded at compile time (4965979).
1439 if (!is_known_inst) { // Do it only for non-instance types
1440 tj = to = TypeInstPtr::make(TypePtr::BotPTR, env()->Object_klass(), false, NULL, offset);
1441 }
1442 } else if (offset < 0 || offset >= k->size_helper() * wordSize) {
1443 // Static fields are in the space above the normal instance
1444 // fields in the java.lang.Class instance.
1445 if (to->klass() != ciEnv::current()->Class_klass()) {
1446 to = NULL;
1447 tj = TypeOopPtr::BOTTOM;
1448 offset = tj->offset();
1449 }
1450 } else {
1451 ciInstanceKlass *canonical_holder = k->get_canonical_holder(offset);
1452 if (!k->equals(canonical_holder) || tj->offset() != offset) {
1453 if( is_known_inst ) {
1454 tj = to = TypeInstPtr::make(to->ptr(), canonical_holder, true, NULL, offset, to->instance_id());
1455 } else {
1456 tj = to = TypeInstPtr::make(to->ptr(), canonical_holder, false, NULL, offset);
1457 }
1458 }
1459 }
1460 }
1461
1462 // Klass pointers to object array klasses need some flattening
1463 const TypeKlassPtr *tk = tj->isa_klassptr();
1464 if( tk ) {
1465 // If we are referencing a field within a Klass, we need
1466 // to assume the worst case of an Object. Both exact and
1467 // inexact types must flatten to the same alias class so
1468 // use NotNull as the PTR.
1469 if ( offset == Type::OffsetBot || (offset >= 0 && (size_t)offset < sizeof(Klass)) ) {
1470
1471 tj = tk = TypeKlassPtr::make(TypePtr::NotNull,
1472 TypeKlassPtr::OBJECT->klass(),
1473 offset);
1474 }
1475
1476 ciKlass* klass = tk->klass();
1477 if( klass->is_obj_array_klass() ) {
1478 ciKlass* k = TypeAryPtr::OOPS->klass();
1479 if( !k || !k->is_loaded() ) // Only fails for some -Xcomp runs
1480 k = TypeInstPtr::BOTTOM->klass();
1481 tj = tk = TypeKlassPtr::make( TypePtr::NotNull, k, offset );
1482 }
1483
1484 // Check for precise loads from the primary supertype array and force them
1485 // to the supertype cache alias index. Check for generic array loads from
1486 // the primary supertype array and also force them to the supertype cache
1487 // alias index. Since the same load can reach both, we need to merge
1488 // these 2 disparate memories into the same alias class. Since the
1489 // primary supertype array is read-only, there's no chance of confusion
1490 // where we bypass an array load and an array store.
1491 int primary_supers_offset = in_bytes(Klass::primary_supers_offset());
1492 if (offset == Type::OffsetBot ||
1493 (offset >= primary_supers_offset &&
1494 offset < (int)(primary_supers_offset + Klass::primary_super_limit() * wordSize)) ||
1495 offset == (int)in_bytes(Klass::secondary_super_cache_offset())) {
1496 offset = in_bytes(Klass::secondary_super_cache_offset());
1497 tj = tk = TypeKlassPtr::make( TypePtr::NotNull, tk->klass(), offset );
1498 }
1499 }
1500
1501 // Flatten all Raw pointers together.
1502 if (tj->base() == Type::RawPtr)
1503 tj = TypeRawPtr::BOTTOM;
1504
1505 if (tj->base() == Type::AnyPtr)
1506 tj = TypePtr::BOTTOM; // An error, which the caller must check for.
1507
1508 // Flatten all to bottom for now
1509 switch( _AliasLevel ) {
1510 case 0:
1511 tj = TypePtr::BOTTOM;
1512 break;
1513 case 1: // Flatten to: oop, static, field or array
1514 switch (tj->base()) {
1515 //case Type::AryPtr: tj = TypeAryPtr::RANGE; break;
1516 case Type::RawPtr: tj = TypeRawPtr::BOTTOM; break;
1517 case Type::AryPtr: // do not distinguish arrays at all
1518 case Type::InstPtr: tj = TypeInstPtr::BOTTOM; break;
1519 case Type::KlassPtr: tj = TypeKlassPtr::OBJECT; break;
1520 case Type::AnyPtr: tj = TypePtr::BOTTOM; break; // caller checks it
1521 default: ShouldNotReachHere();
1522 }
1523 break;
1524 case 2: // No collapsing at level 2; keep all splits
1525 case 3: // No collapsing at level 3; keep all splits
1526 break;
1527 default:
1528 Unimplemented();
1529 }
1530
1531 offset = tj->offset();
1532 assert( offset != Type::OffsetTop, "Offset has fallen from constant" );
1533
1534 assert( (offset != Type::OffsetBot && tj->base() != Type::AryPtr) ||
1535 (offset == Type::OffsetBot && tj->base() == Type::AryPtr) ||
1536 (offset == Type::OffsetBot && tj == TypeOopPtr::BOTTOM) ||
1537 (offset == Type::OffsetBot && tj == TypePtr::BOTTOM) ||
1538 (offset == oopDesc::mark_offset_in_bytes() && tj->base() == Type::AryPtr) ||
1539 (offset == oopDesc::klass_offset_in_bytes() && tj->base() == Type::AryPtr) ||
1540 (offset == arrayOopDesc::length_offset_in_bytes() && tj->base() == Type::AryPtr) ,
1541 "For oops, klasses, raw offset must be constant; for arrays the offset is never known" );
1542 assert( tj->ptr() != TypePtr::TopPTR &&
1543 tj->ptr() != TypePtr::AnyNull &&
1544 tj->ptr() != TypePtr::Null, "No imprecise addresses" );
1545 // assert( tj->ptr() != TypePtr::Constant ||
1546 // tj->base() == Type::RawPtr ||
1547 // tj->base() == Type::KlassPtr, "No constant oop addresses" );
1548
1549 return tj;
1550 }
1551
1552 void Compile::AliasType::Init(int i, const TypePtr* at) {
1553 _index = i;
1554 _adr_type = at;
1555 _field = NULL;
1556 _element = NULL;
1557 _is_rewritable = true; // default
1558 const TypeOopPtr *atoop = (at != NULL) ? at->isa_oopptr() : NULL;
1559 if (atoop != NULL && atoop->is_known_instance()) {
1560 const TypeOopPtr *gt = atoop->cast_to_instance_id(TypeOopPtr::InstanceBot);
1561 _general_index = Compile::current()->get_alias_index(gt);
1562 } else {
1563 _general_index = 0;
1564 }
1565 }
1566
1567 //---------------------------------print_on------------------------------------
1568 #ifndef PRODUCT
1569 void Compile::AliasType::print_on(outputStream* st) {
1570 if (index() < 10)
1571 st->print("@ <%d> ", index());
1572 else st->print("@ <%d>", index());
1573 st->print(is_rewritable() ? " " : " RO");
1574 int offset = adr_type()->offset();
1575 if (offset == Type::OffsetBot)
1576 st->print(" +any");
1577 else st->print(" +%-3d", offset);
1578 st->print(" in ");
1579 adr_type()->dump_on(st);
1580 const TypeOopPtr* tjp = adr_type()->isa_oopptr();
1581 if (field() != NULL && tjp) {
1582 if (tjp->klass() != field()->holder() ||
1583 tjp->offset() != field()->offset_in_bytes()) {
1584 st->print(" != ");
1585 field()->print();
1586 st->print(" ***");
1587 }
1588 }
1589 }
1590
1591 void print_alias_types() {
1592 Compile* C = Compile::current();
1593 tty->print_cr("--- Alias types, AliasIdxBot .. %d", C->num_alias_types()-1);
1594 for (int idx = Compile::AliasIdxBot; idx < C->num_alias_types(); idx++) {
1595 C->alias_type(idx)->print_on(tty);
1596 tty->cr();
1597 }
1598 }
1599 #endif
1600
1601
1602 //----------------------------probe_alias_cache--------------------------------
1603 Compile::AliasCacheEntry* Compile::probe_alias_cache(const TypePtr* adr_type) {
1604 intptr_t key = (intptr_t) adr_type;
1605 key ^= key >> logAliasCacheSize;
1606 return &_alias_cache[key & right_n_bits(logAliasCacheSize)];
1607 }
1608
1609
1610 //-----------------------------grow_alias_types--------------------------------
1611 void Compile::grow_alias_types() {
1612 const int old_ats = _max_alias_types; // how many before?
1613 const int new_ats = old_ats; // how many more?
1614 const int grow_ats = old_ats+new_ats; // how many now?
1615 _max_alias_types = grow_ats;
1616 _alias_types = REALLOC_ARENA_ARRAY(comp_arena(), AliasType*, _alias_types, old_ats, grow_ats);
1617 AliasType* ats = NEW_ARENA_ARRAY(comp_arena(), AliasType, new_ats);
1618 Copy::zero_to_bytes(ats, sizeof(AliasType)*new_ats);
1619 for (int i = 0; i < new_ats; i++) _alias_types[old_ats+i] = &ats[i];
1620 }
1621
1622
1623 //--------------------------------find_alias_type------------------------------
1624 Compile::AliasType* Compile::find_alias_type(const TypePtr* adr_type, bool no_create, ciField* original_field) {
1625 if (_AliasLevel == 0)
1626 return alias_type(AliasIdxBot);
1627
1628 AliasCacheEntry* ace = probe_alias_cache(adr_type);
1629 if (ace->_adr_type == adr_type) {
1630 return alias_type(ace->_index);
1631 }
1632
1633 // Handle special cases.
1634 if (adr_type == NULL) return alias_type(AliasIdxTop);
1635 if (adr_type == TypePtr::BOTTOM) return alias_type(AliasIdxBot);
1636
1637 // Do it the slow way.
1638 const TypePtr* flat = flatten_alias_type(adr_type);
1639
1640 #ifdef ASSERT
1641 assert(flat == flatten_alias_type(flat), "idempotent");
1642 assert(flat != TypePtr::BOTTOM, "cannot alias-analyze an untyped ptr");
1643 if (flat->isa_oopptr() && !flat->isa_klassptr()) {
1644 const TypeOopPtr* foop = flat->is_oopptr();
1645 // Scalarizable allocations have exact klass always.
1646 bool exact = !foop->klass_is_exact() || foop->is_known_instance();
1647 const TypePtr* xoop = foop->cast_to_exactness(exact)->is_ptr();
1648 assert(foop == flatten_alias_type(xoop), "exactness must not affect alias type");
1649 }
1650 assert(flat == flatten_alias_type(flat), "exact bit doesn't matter");
1651 #endif
1652
1653 int idx = AliasIdxTop;
1654 for (int i = 0; i < num_alias_types(); i++) {
1655 if (alias_type(i)->adr_type() == flat) {
1656 idx = i;
1657 break;
1658 }
1659 }
1660
1661 if (idx == AliasIdxTop) {
1662 if (no_create) return NULL;
1663 // Grow the array if necessary.
1664 if (_num_alias_types == _max_alias_types) grow_alias_types();
1665 // Add a new alias type.
1666 idx = _num_alias_types++;
1667 _alias_types[idx]->Init(idx, flat);
1668 if (flat == TypeInstPtr::KLASS) alias_type(idx)->set_rewritable(false);
1669 if (flat == TypeAryPtr::RANGE) alias_type(idx)->set_rewritable(false);
1670 if (flat->isa_instptr()) {
1671 if (flat->offset() == java_lang_Class::klass_offset_in_bytes()
1672 && flat->is_instptr()->klass() == env()->Class_klass())
1673 alias_type(idx)->set_rewritable(false);
1674 }
1675 if (flat->isa_aryptr()) {
1676 #ifdef ASSERT
1677 const int header_size_min = arrayOopDesc::base_offset_in_bytes(T_BYTE);
1678 // (T_BYTE has the weakest alignment and size restrictions...)
1679 assert(flat->offset() < header_size_min, "array body reference must be OffsetBot");
1680 #endif
1681 if (flat->offset() == TypePtr::OffsetBot) {
1682 alias_type(idx)->set_element(flat->is_aryptr()->elem());
1683 }
1684 }
1685 if (flat->isa_klassptr()) {
1686 if (flat->offset() == in_bytes(Klass::super_check_offset_offset()))
1687 alias_type(idx)->set_rewritable(false);
1688 if (flat->offset() == in_bytes(Klass::modifier_flags_offset()))
1689 alias_type(idx)->set_rewritable(false);
1690 if (flat->offset() == in_bytes(Klass::access_flags_offset()))
1691 alias_type(idx)->set_rewritable(false);
1692 if (flat->offset() == in_bytes(Klass::java_mirror_offset()))
1693 alias_type(idx)->set_rewritable(false);
1694 }
1695 // %%% (We would like to finalize JavaThread::threadObj_offset(),
1696 // but the base pointer type is not distinctive enough to identify
1697 // references into JavaThread.)
1698
1699 // Check for final fields.
1700 const TypeInstPtr* tinst = flat->isa_instptr();
1701 if (tinst && tinst->offset() >= instanceOopDesc::base_offset_in_bytes()) {
1702 ciField* field;
1703 if (tinst->const_oop() != NULL &&
1704 tinst->klass() == ciEnv::current()->Class_klass() &&
1705 tinst->offset() >= (tinst->klass()->as_instance_klass()->size_helper() * wordSize)) {
1706 // static field
1707 ciInstanceKlass* k = tinst->const_oop()->as_instance()->java_lang_Class_klass()->as_instance_klass();
1708 field = k->get_field_by_offset(tinst->offset(), true);
1709 } else {
1710 ciInstanceKlass *k = tinst->klass()->as_instance_klass();
1711 field = k->get_field_by_offset(tinst->offset(), false);
1712 }
1713 assert(field == NULL ||
1714 original_field == NULL ||
1715 (field->holder() == original_field->holder() &&
1716 field->offset() == original_field->offset() &&
1717 field->is_static() == original_field->is_static()), "wrong field?");
1718 // Set field() and is_rewritable() attributes.
1719 if (field != NULL) alias_type(idx)->set_field(field);
1720 }
1721 }
1722
1723 // Fill the cache for next time.
1724 ace->_adr_type = adr_type;
1725 ace->_index = idx;
1726 assert(alias_type(adr_type) == alias_type(idx), "type must be installed");
1727
1728 // Might as well try to fill the cache for the flattened version, too.
1729 AliasCacheEntry* face = probe_alias_cache(flat);
1730 if (face->_adr_type == NULL) {
1731 face->_adr_type = flat;
1732 face->_index = idx;
1733 assert(alias_type(flat) == alias_type(idx), "flat type must work too");
1734 }
1735
1736 return alias_type(idx);
1737 }
1738
1739
1740 Compile::AliasType* Compile::alias_type(ciField* field) {
1741 const TypeOopPtr* t;
1742 if (field->is_static())
1743 t = TypeInstPtr::make(field->holder()->java_mirror());
1744 else
1745 t = TypeOopPtr::make_from_klass_raw(field->holder());
1746 AliasType* atp = alias_type(t->add_offset(field->offset_in_bytes()), field);
1747 assert((field->is_final() || field->is_stable()) == !atp->is_rewritable(), "must get the rewritable bits correct");
1748 return atp;
1749 }
1750
1751
1752 //------------------------------have_alias_type--------------------------------
1753 bool Compile::have_alias_type(const TypePtr* adr_type) {
1754 AliasCacheEntry* ace = probe_alias_cache(adr_type);
1755 if (ace->_adr_type == adr_type) {
1756 return true;
1757 }
1758
1759 // Handle special cases.
1760 if (adr_type == NULL) return true;
1761 if (adr_type == TypePtr::BOTTOM) return true;
1762
1763 return find_alias_type(adr_type, true, NULL) != NULL;
1764 }
1765
1766 //-----------------------------must_alias--------------------------------------
1767 // True if all values of the given address type are in the given alias category.
1768 bool Compile::must_alias(const TypePtr* adr_type, int alias_idx) {
1769 if (alias_idx == AliasIdxBot) return true; // the universal category
1770 if (adr_type == NULL) return true; // NULL serves as TypePtr::TOP
1771 if (alias_idx == AliasIdxTop) return false; // the empty category
1772 if (adr_type->base() == Type::AnyPtr) return false; // TypePtr::BOTTOM or its twins
1773
1774 // the only remaining possible overlap is identity
1775 int adr_idx = get_alias_index(adr_type);
1776 assert(adr_idx != AliasIdxBot && adr_idx != AliasIdxTop, "");
1777 assert(adr_idx == alias_idx ||
1778 (alias_type(alias_idx)->adr_type() != TypeOopPtr::BOTTOM
1779 && adr_type != TypeOopPtr::BOTTOM),
1780 "should not be testing for overlap with an unsafe pointer");
1781 return adr_idx == alias_idx;
1782 }
1783
1784 //------------------------------can_alias--------------------------------------
1785 // True if any values of the given address type are in the given alias category.
1786 bool Compile::can_alias(const TypePtr* adr_type, int alias_idx) {
1787 if (alias_idx == AliasIdxTop) return false; // the empty category
1788 if (adr_type == NULL) return false; // NULL serves as TypePtr::TOP
1789 if (alias_idx == AliasIdxBot) return true; // the universal category
1790 if (adr_type->base() == Type::AnyPtr) return true; // TypePtr::BOTTOM or its twins
1791
1792 // the only remaining possible overlap is identity
1793 int adr_idx = get_alias_index(adr_type);
1794 assert(adr_idx != AliasIdxBot && adr_idx != AliasIdxTop, "");
1795 return adr_idx == alias_idx;
1796 }
1797
1798
1799
1800 //---------------------------pop_warm_call-------------------------------------
1801 WarmCallInfo* Compile::pop_warm_call() {
1802 WarmCallInfo* wci = _warm_calls;
1803 if (wci != NULL) _warm_calls = wci->remove_from(wci);
1804 return wci;
1805 }
1806
1807 //----------------------------Inline_Warm--------------------------------------
1808 int Compile::Inline_Warm() {
1809 // If there is room, try to inline some more warm call sites.
1810 // %%% Do a graph index compaction pass when we think we're out of space?
1811 if (!InlineWarmCalls) return 0;
1812
1813 int calls_made_hot = 0;
1814 int room_to_grow = NodeCountInliningCutoff - unique();
1815 int amount_to_grow = MIN2(room_to_grow, (int)NodeCountInliningStep);
1816 int amount_grown = 0;
1817 WarmCallInfo* call;
1818 while (amount_to_grow > 0 && (call = pop_warm_call()) != NULL) {
1819 int est_size = (int)call->size();
1820 if (est_size > (room_to_grow - amount_grown)) {
1821 // This one won't fit anyway. Get rid of it.
1822 call->make_cold();
1823 continue;
1824 }
1825 call->make_hot();
1826 calls_made_hot++;
1827 amount_grown += est_size;
1828 amount_to_grow -= est_size;
1829 }
1830
1831 if (calls_made_hot > 0) set_major_progress();
1832 return calls_made_hot;
1833 }
1834
1835
1836 //----------------------------Finish_Warm--------------------------------------
1837 void Compile::Finish_Warm() {
1838 if (!InlineWarmCalls) return;
1839 if (failing()) return;
1840 if (warm_calls() == NULL) return;
1841
1842 // Clean up loose ends, if we are out of space for inlining.
1843 WarmCallInfo* call;
1844 while ((call = pop_warm_call()) != NULL) {
1845 call->make_cold();
1846 }
1847 }
1848
1849 //---------------------cleanup_loop_predicates-----------------------
1850 // Remove the opaque nodes that protect the predicates so that all unused
1851 // checks and uncommon_traps will be eliminated from the ideal graph
1852 void Compile::cleanup_loop_predicates(PhaseIterGVN &igvn) {
1853 if (predicate_count()==0) return;
1854 for (int i = predicate_count(); i > 0; i--) {
1855 Node * n = predicate_opaque1_node(i-1);
1856 assert(n->Opcode() == Op_Opaque1, "must be");
1857 igvn.replace_node(n, n->in(1));
1858 }
1859 assert(predicate_count()==0, "should be clean!");
1860 }
1861
1862 // StringOpts and late inlining of string methods
1863 void Compile::inline_string_calls(bool parse_time) {
1864 {
1865 // remove useless nodes to make the usage analysis simpler
1866 ResourceMark rm;
1867 PhaseRemoveUseless pru(initial_gvn(), for_igvn());
1868 }
1869
1870 {
1871 ResourceMark rm;
1872 print_method(PHASE_BEFORE_STRINGOPTS, 3);
1873 PhaseStringOpts pso(initial_gvn(), for_igvn());
1874 print_method(PHASE_AFTER_STRINGOPTS, 3);
1875 }
1876
1877 // now inline anything that we skipped the first time around
1878 if (!parse_time) {
1879 _late_inlines_pos = _late_inlines.length();
1880 }
1881
1882 while (_string_late_inlines.length() > 0) {
1883 CallGenerator* cg = _string_late_inlines.pop();
1884 cg->do_late_inline();
1885 if (failing()) return;
1886 }
1887 _string_late_inlines.trunc_to(0);
1888 }
1889
1890 // Late inlining of boxing methods
1891 void Compile::inline_boxing_calls(PhaseIterGVN& igvn) {
1892 if (_boxing_late_inlines.length() > 0) {
1893 assert(has_boxed_value(), "inconsistent");
1894
1895 PhaseGVN* gvn = initial_gvn();
1896 set_inlining_incrementally(true);
1897
1898 assert( igvn._worklist.size() == 0, "should be done with igvn" );
1899 for_igvn()->clear();
1900 gvn->replace_with(&igvn);
1901
1902 _late_inlines_pos = _late_inlines.length();
1903
1904 while (_boxing_late_inlines.length() > 0) {
1905 CallGenerator* cg = _boxing_late_inlines.pop();
1906 cg->do_late_inline();
1907 if (failing()) return;
1908 }
1909 _boxing_late_inlines.trunc_to(0);
1910
1911 {
1912 ResourceMark rm;
1913 PhaseRemoveUseless pru(gvn, for_igvn());
1914 }
1915
1916 igvn = PhaseIterGVN(gvn);
1917 igvn.optimize();
1918
1919 set_inlining_progress(false);
1920 set_inlining_incrementally(false);
1921 }
1922 }
1923
1924 void Compile::inline_incrementally_one(PhaseIterGVN& igvn) {
1925 assert(IncrementalInline, "incremental inlining should be on");
1926 PhaseGVN* gvn = initial_gvn();
1927
1928 set_inlining_progress(false);
1929 for_igvn()->clear();
1930 gvn->replace_with(&igvn);
1931
1932 int i = 0;
1933
1934 for (; i <_late_inlines.length() && !inlining_progress(); i++) {
1935 CallGenerator* cg = _late_inlines.at(i);
1936 _late_inlines_pos = i+1;
1937 cg->do_late_inline();
1938 if (failing()) return;
1939 }
1940 int j = 0;
1941 for (; i < _late_inlines.length(); i++, j++) {
1942 _late_inlines.at_put(j, _late_inlines.at(i));
1943 }
1944 _late_inlines.trunc_to(j);
1945
1946 {
1947 ResourceMark rm;
1948 PhaseRemoveUseless pru(gvn, for_igvn());
1949 }
1950
1951 igvn = PhaseIterGVN(gvn);
1952 }
1953
1954 // Perform incremental inlining until bound on number of live nodes is reached
1955 void Compile::inline_incrementally(PhaseIterGVN& igvn) {
1956 PhaseGVN* gvn = initial_gvn();
1957
1958 set_inlining_incrementally(true);
1959 set_inlining_progress(true);
1960 uint low_live_nodes = 0;
1961
1962 while(inlining_progress() && _late_inlines.length() > 0) {
1963
1964 if (live_nodes() > (uint)LiveNodeCountInliningCutoff) {
1965 if (low_live_nodes < (uint)LiveNodeCountInliningCutoff * 8 / 10) {
1966 // PhaseIdealLoop is expensive so we only try it once we are
1967 // out of live nodes and we only try it again if the previous
1968 // helped got the number of nodes down significantly
1969 PhaseIdealLoop ideal_loop( igvn, false, true );
1970 if (failing()) return;
1971 low_live_nodes = live_nodes();
1972 _major_progress = true;
1973 }
1974
1975 if (live_nodes() > (uint)LiveNodeCountInliningCutoff) {
1976 break;
1977 }
1978 }
1979
1980 inline_incrementally_one(igvn);
1981
1982 if (failing()) return;
1983
1984 igvn.optimize();
1985
1986 if (failing()) return;
1987 }
1988
1989 assert( igvn._worklist.size() == 0, "should be done with igvn" );
1990
1991 if (_string_late_inlines.length() > 0) {
1992 assert(has_stringbuilder(), "inconsistent");
1993 for_igvn()->clear();
1994 initial_gvn()->replace_with(&igvn);
1995
1996 inline_string_calls(false);
1997
1998 if (failing()) return;
1999
2000 {
2001 ResourceMark rm;
2002 PhaseRemoveUseless pru(initial_gvn(), for_igvn());
2003 }
2004
2005 igvn = PhaseIterGVN(gvn);
2006
2007 igvn.optimize();
2008 }
2009
2010 set_inlining_incrementally(false);
2011 }
2012
2013
2014 //------------------------------Optimize---------------------------------------
2015 // Given a graph, optimize it.
2016 void Compile::Optimize() {
2017 TracePhase t1("optimizer", &_t_optimizer, true);
2018
2019 #ifndef PRODUCT
2020 if (env()->break_at_compile()) {
2021 BREAKPOINT;
2022 }
2023
2024 #endif
2025
2026 ResourceMark rm;
2027 int loop_opts_cnt;
2028
2029 print_inlining_reinit();
2030
2031 NOT_PRODUCT( verify_graph_edges(); )
2032
2033 print_method(PHASE_AFTER_PARSING);
2034
2035 {
2036 // Iterative Global Value Numbering, including ideal transforms
2037 // Initialize IterGVN with types and values from parse-time GVN
2038 PhaseIterGVN igvn(initial_gvn());
2039 {
2040 NOT_PRODUCT( TracePhase t2("iterGVN", &_t_iterGVN, TimeCompiler); )
2041 igvn.optimize();
2042 }
2043
2044 print_method(PHASE_ITER_GVN1, 2);
2045
2046 if (failing()) return;
2047
2048 {
2049 NOT_PRODUCT( TracePhase t2("incrementalInline", &_t_incrInline, TimeCompiler); )
2050 inline_incrementally(igvn);
2051 }
2052
2053 print_method(PHASE_INCREMENTAL_INLINE, 2);
2054
2055 if (failing()) return;
2056
2057 if (eliminate_boxing()) {
2058 NOT_PRODUCT( TracePhase t2("incrementalInline", &_t_incrInline, TimeCompiler); )
2059 // Inline valueOf() methods now.
2060 inline_boxing_calls(igvn);
2061
2062 if (AlwaysIncrementalInline) {
2063 inline_incrementally(igvn);
2064 }
2065
2066 print_method(PHASE_INCREMENTAL_BOXING_INLINE, 2);
2067
2068 if (failing()) return;
2069 }
2070
2071 // Remove the speculative part of types and clean up the graph from
2072 // the extra CastPP nodes whose only purpose is to carry them. Do
2073 // that early so that optimizations are not disrupted by the extra
2074 // CastPP nodes.
2075 remove_speculative_types(igvn);
2076
2077 // No more new expensive nodes will be added to the list from here
2078 // so keep only the actual candidates for optimizations.
2079 cleanup_expensive_nodes(igvn);
2080
2081 // Perform escape analysis
2082 if (_do_escape_analysis && ConnectionGraph::has_candidates(this)) {
2083 if (has_loops()) {
2084 // Cleanup graph (remove dead nodes).
2085 TracePhase t2("idealLoop", &_t_idealLoop, true);
2086 PhaseIdealLoop ideal_loop( igvn, false, true );
2087 if (major_progress()) print_method(PHASE_PHASEIDEAL_BEFORE_EA, 2);
2088 if (failing()) return;
2089 }
2090 ConnectionGraph::do_analysis(this, &igvn);
2091
2092 if (failing()) return;
2093
2094 // Optimize out fields loads from scalar replaceable allocations.
2095 igvn.optimize();
2096 print_method(PHASE_ITER_GVN_AFTER_EA, 2);
2097
2098 if (failing()) return;
2099
2100 if (congraph() != NULL && macro_count() > 0) {
2101 NOT_PRODUCT( TracePhase t2("macroEliminate", &_t_macroEliminate, TimeCompiler); )
2102 PhaseMacroExpand mexp(igvn);
2103 mexp.eliminate_macro_nodes();
2104 igvn.set_delay_transform(false);
2105
2106 igvn.optimize();
2107 print_method(PHASE_ITER_GVN_AFTER_ELIMINATION, 2);
2108
2109 if (failing()) return;
2110 }
2111 }
2112
2113 // Loop transforms on the ideal graph. Range Check Elimination,
2114 // peeling, unrolling, etc.
2115
2116 // Set loop opts counter
2117 loop_opts_cnt = num_loop_opts();
2118 if((loop_opts_cnt > 0) && (has_loops() || has_split_ifs())) {
2119 {
2120 TracePhase t2("idealLoop", &_t_idealLoop, true);
2121 PhaseIdealLoop ideal_loop( igvn, true );
2122 loop_opts_cnt--;
2123 if (major_progress()) print_method(PHASE_PHASEIDEALLOOP1, 2);
2124 if (failing()) return;
2125 }
2126 // Loop opts pass if partial peeling occurred in previous pass
2127 if(PartialPeelLoop && major_progress() && (loop_opts_cnt > 0)) {
2128 TracePhase t3("idealLoop", &_t_idealLoop, true);
2129 PhaseIdealLoop ideal_loop( igvn, false );
2130 loop_opts_cnt--;
2131 if (major_progress()) print_method(PHASE_PHASEIDEALLOOP2, 2);
2132 if (failing()) return;
2133 }
2134 // Loop opts pass for loop-unrolling before CCP
2135 if(major_progress() && (loop_opts_cnt > 0)) {
2136 TracePhase t4("idealLoop", &_t_idealLoop, true);
2137 PhaseIdealLoop ideal_loop( igvn, false );
2138 loop_opts_cnt--;
2139 if (major_progress()) print_method(PHASE_PHASEIDEALLOOP3, 2);
2140 }
2141 if (!failing()) {
2142 // Verify that last round of loop opts produced a valid graph
2143 NOT_PRODUCT( TracePhase t2("idealLoopVerify", &_t_idealLoopVerify, TimeCompiler); )
2144 PhaseIdealLoop::verify(igvn);
2145 }
2146 }
2147 if (failing()) return;
2148
2149 // Conditional Constant Propagation;
2150 PhaseCCP ccp( &igvn );
2151 assert( true, "Break here to ccp.dump_nodes_and_types(_root,999,1)");
2152 {
2153 TracePhase t2("ccp", &_t_ccp, true);
2154 ccp.do_transform();
2155 }
2156 print_method(PHASE_CPP1, 2);
2157
2158 assert( true, "Break here to ccp.dump_old2new_map()");
2159
2160 // Iterative Global Value Numbering, including ideal transforms
2161 {
2162 NOT_PRODUCT( TracePhase t2("iterGVN2", &_t_iterGVN2, TimeCompiler); )
2163 igvn = ccp;
2164 igvn.optimize();
2165 }
2166
2167 print_method(PHASE_ITER_GVN2, 2);
2168
2169 if (failing()) return;
2170
2171 // Loop transforms on the ideal graph. Range Check Elimination,
2172 // peeling, unrolling, etc.
2173 if(loop_opts_cnt > 0) {
2174 debug_only( int cnt = 0; );
2175 while(major_progress() && (loop_opts_cnt > 0)) {
2176 TracePhase t2("idealLoop", &_t_idealLoop, true);
2177 assert( cnt++ < 40, "infinite cycle in loop optimization" );
2178 PhaseIdealLoop ideal_loop( igvn, true);
2179 loop_opts_cnt--;
2180 if (major_progress()) print_method(PHASE_PHASEIDEALLOOP_ITERATIONS, 2);
2181 if (failing()) return;
2182 }
2183 }
2184
2185 {
2186 // Verify that all previous optimizations produced a valid graph
2187 // at least to this point, even if no loop optimizations were done.
2188 NOT_PRODUCT( TracePhase t2("idealLoopVerify", &_t_idealLoopVerify, TimeCompiler); )
2189 PhaseIdealLoop::verify(igvn);
2190 }
2191
2192 {
2193 NOT_PRODUCT( TracePhase t2("macroExpand", &_t_macroExpand, TimeCompiler); )
2194 PhaseMacroExpand mex(igvn);
2195 if (mex.expand_macro_nodes()) {
2196 assert(failing(), "must bail out w/ explicit message");
2197 return;
2198 }
2199 }
2200
2201 } // (End scope of igvn; run destructor if necessary for asserts.)
2202
2203 process_print_inlining();
2204 // A method with only infinite loops has no edges entering loops from root
2205 {
2206 NOT_PRODUCT( TracePhase t2("graphReshape", &_t_graphReshaping, TimeCompiler); )
2207 if (final_graph_reshaping()) {
2208 assert(failing(), "must bail out w/ explicit message");
2209 return;
2210 }
2211 }
2212
2213 print_method(PHASE_OPTIMIZE_FINISHED, 2);
2214 }
2215
2216
2217 //------------------------------Code_Gen---------------------------------------
2218 // Given a graph, generate code for it
2219 void Compile::Code_Gen() {
2220 if (failing()) {
2221 return;
2222 }
2223
2224 // Perform instruction selection. You might think we could reclaim Matcher
2225 // memory PDQ, but actually the Matcher is used in generating spill code.
2226 // Internals of the Matcher (including some VectorSets) must remain live
2227 // for awhile - thus I cannot reclaim Matcher memory lest a VectorSet usage
2228 // set a bit in reclaimed memory.
2229
2230 // In debug mode can dump m._nodes.dump() for mapping of ideal to machine
2231 // nodes. Mapping is only valid at the root of each matched subtree.
2232 NOT_PRODUCT( verify_graph_edges(); )
2233
2234 Matcher matcher;
2235 _matcher = &matcher;
2236 {
2237 TracePhase t2("matcher", &_t_matcher, true);
2238 matcher.match();
2239 }
2240 // In debug mode can dump m._nodes.dump() for mapping of ideal to machine
2241 // nodes. Mapping is only valid at the root of each matched subtree.
2242 NOT_PRODUCT( verify_graph_edges(); )
2243
2244 // If you have too many nodes, or if matching has failed, bail out
2245 check_node_count(0, "out of nodes matching instructions");
2246 if (failing()) {
2247 return;
2248 }
2249
2250 // Build a proper-looking CFG
2251 PhaseCFG cfg(node_arena(), root(), matcher);
2252 _cfg = &cfg;
2253 {
2254 NOT_PRODUCT( TracePhase t2("scheduler", &_t_scheduler, TimeCompiler); )
2255 bool success = cfg.do_global_code_motion();
2256 if (!success) {
2257 return;
2258 }
2259
2260 print_method(PHASE_GLOBAL_CODE_MOTION, 2);
2261 NOT_PRODUCT( verify_graph_edges(); )
2262 debug_only( cfg.verify(); )
2263 }
2264
2265 PhaseChaitin regalloc(unique(), cfg, matcher);
2266 _regalloc = ®alloc;
2267 {
2268 TracePhase t2("regalloc", &_t_registerAllocation, true);
2269 // Perform register allocation. After Chaitin, use-def chains are
2270 // no longer accurate (at spill code) and so must be ignored.
2271 // Node->LRG->reg mappings are still accurate.
2272 _regalloc->Register_Allocate();
2273
2274 // Bail out if the allocator builds too many nodes
2275 if (failing()) {
2276 return;
2277 }
2278 }
2279
2280 // Prior to register allocation we kept empty basic blocks in case the
2281 // the allocator needed a place to spill. After register allocation we
2282 // are not adding any new instructions. If any basic block is empty, we
2283 // can now safely remove it.
2284 {
2285 NOT_PRODUCT( TracePhase t2("blockOrdering", &_t_blockOrdering, TimeCompiler); )
2286 cfg.remove_empty_blocks();
2287 if (do_freq_based_layout()) {
2288 PhaseBlockLayout layout(cfg);
2289 } else {
2290 cfg.set_loop_alignment();
2291 }
2292 cfg.fixup_flow();
2293 }
2294
2295 // Apply peephole optimizations
2296 if( OptoPeephole ) {
2297 NOT_PRODUCT( TracePhase t2("peephole", &_t_peephole, TimeCompiler); )
2298 PhasePeephole peep( _regalloc, cfg);
2299 peep.do_transform();
2300 }
2301
2302 // Do late expand if CPU requires this.
2303 if (Matcher::require_postalloc_expand) {
2304 NOT_PRODUCT(TracePhase t2c("postalloc_expand", &_t_postalloc_expand, true));
2305 cfg.postalloc_expand(_regalloc);
2306 }
2307
2308 // Convert Nodes to instruction bits in a buffer
2309 {
2310 // %%%% workspace merge brought two timers together for one job
2311 TracePhase t2a("output", &_t_output, true);
2312 NOT_PRODUCT( TraceTime t2b(NULL, &_t_codeGeneration, TimeCompiler, false); )
2313 Output();
2314 }
2315
2316 print_method(PHASE_FINAL_CODE);
2317
2318 // He's dead, Jim.
2319 _cfg = (PhaseCFG*)0xdeadbeef;
2320 _regalloc = (PhaseChaitin*)0xdeadbeef;
2321 }
2322
2323
2324 //------------------------------dump_asm---------------------------------------
2325 // Dump formatted assembly
2326 #ifndef PRODUCT
2327 void Compile::dump_asm(int *pcs, uint pc_limit) {
2328 bool cut_short = false;
2329 tty->print_cr("#");
2330 tty->print("# "); _tf->dump(); tty->cr();
2331 tty->print_cr("#");
2332
2333 // For all blocks
2334 int pc = 0x0; // Program counter
2335 char starts_bundle = ' ';
2336 _regalloc->dump_frame();
2337
2338 Node *n = NULL;
2339 for (uint i = 0; i < _cfg->number_of_blocks(); i++) {
2340 if (VMThread::should_terminate()) {
2341 cut_short = true;
2342 break;
2343 }
2344 Block* block = _cfg->get_block(i);
2345 if (block->is_connector() && !Verbose) {
2346 continue;
2347 }
2348 n = block->head();
2349 if (pcs && n->_idx < pc_limit) {
2350 tty->print("%3.3x ", pcs[n->_idx]);
2351 } else {
2352 tty->print(" ");
2353 }
2354 block->dump_head(_cfg);
2355 if (block->is_connector()) {
2356 tty->print_cr(" # Empty connector block");
2357 } else if (block->num_preds() == 2 && block->pred(1)->is_CatchProj() && block->pred(1)->as_CatchProj()->_con == CatchProjNode::fall_through_index) {
2358 tty->print_cr(" # Block is sole successor of call");
2359 }
2360
2361 // For all instructions
2362 Node *delay = NULL;
2363 for (uint j = 0; j < block->number_of_nodes(); j++) {
2364 if (VMThread::should_terminate()) {
2365 cut_short = true;
2366 break;
2367 }
2368 n = block->get_node(j);
2369 if (valid_bundle_info(n)) {
2370 Bundle* bundle = node_bundling(n);
2371 if (bundle->used_in_unconditional_delay()) {
2372 delay = n;
2373 continue;
2374 }
2375 if (bundle->starts_bundle()) {
2376 starts_bundle = '+';
2377 }
2378 }
2379
2380 if (WizardMode) {
2381 n->dump();
2382 }
2383
2384 if( !n->is_Region() && // Dont print in the Assembly
2385 !n->is_Phi() && // a few noisely useless nodes
2386 !n->is_Proj() &&
2387 !n->is_MachTemp() &&
2388 !n->is_SafePointScalarObject() &&
2389 !n->is_Catch() && // Would be nice to print exception table targets
2390 !n->is_MergeMem() && // Not very interesting
2391 !n->is_top() && // Debug info table constants
2392 !(n->is_Con() && !n->is_Mach())// Debug info table constants
2393 ) {
2394 if (pcs && n->_idx < pc_limit)
2395 tty->print("%3.3x", pcs[n->_idx]);
2396 else
2397 tty->print(" ");
2398 tty->print(" %c ", starts_bundle);
2399 starts_bundle = ' ';
2400 tty->print("\t");
2401 n->format(_regalloc, tty);
2402 tty->cr();
2403 }
2404
2405 // If we have an instruction with a delay slot, and have seen a delay,
2406 // then back up and print it
2407 if (valid_bundle_info(n) && node_bundling(n)->use_unconditional_delay()) {
2408 assert(delay != NULL, "no unconditional delay instruction");
2409 if (WizardMode) delay->dump();
2410
2411 if (node_bundling(delay)->starts_bundle())
2412 starts_bundle = '+';
2413 if (pcs && n->_idx < pc_limit)
2414 tty->print("%3.3x", pcs[n->_idx]);
2415 else
2416 tty->print(" ");
2417 tty->print(" %c ", starts_bundle);
2418 starts_bundle = ' ';
2419 tty->print("\t");
2420 delay->format(_regalloc, tty);
2421 tty->cr();
2422 delay = NULL;
2423 }
2424
2425 // Dump the exception table as well
2426 if( n->is_Catch() && (Verbose || WizardMode) ) {
2427 // Print the exception table for this offset
2428 _handler_table.print_subtable_for(pc);
2429 }
2430 }
2431
2432 if (pcs && n->_idx < pc_limit)
2433 tty->print_cr("%3.3x", pcs[n->_idx]);
2434 else
2435 tty->cr();
2436
2437 assert(cut_short || delay == NULL, "no unconditional delay branch");
2438
2439 } // End of per-block dump
2440 tty->cr();
2441
2442 if (cut_short) tty->print_cr("*** disassembly is cut short ***");
2443 }
2444 #endif
2445
2446 //------------------------------Final_Reshape_Counts---------------------------
2447 // This class defines counters to help identify when a method
2448 // may/must be executed using hardware with only 24-bit precision.
2449 struct Final_Reshape_Counts : public StackObj {
2450 int _call_count; // count non-inlined 'common' calls
2451 int _float_count; // count float ops requiring 24-bit precision
2452 int _double_count; // count double ops requiring more precision
2453 int _java_call_count; // count non-inlined 'java' calls
2454 int _inner_loop_count; // count loops which need alignment
2455 VectorSet _visited; // Visitation flags
2456 Node_List _tests; // Set of IfNodes & PCTableNodes
2457
2458 Final_Reshape_Counts() :
2459 _call_count(0), _float_count(0), _double_count(0),
2460 _java_call_count(0), _inner_loop_count(0),
2461 _visited( Thread::current()->resource_area() ) { }
2462
2463 void inc_call_count () { _call_count ++; }
2464 void inc_float_count () { _float_count ++; }
2465 void inc_double_count() { _double_count++; }
2466 void inc_java_call_count() { _java_call_count++; }
2467 void inc_inner_loop_count() { _inner_loop_count++; }
2468
2469 int get_call_count () const { return _call_count ; }
2470 int get_float_count () const { return _float_count ; }
2471 int get_double_count() const { return _double_count; }
2472 int get_java_call_count() const { return _java_call_count; }
2473 int get_inner_loop_count() const { return _inner_loop_count; }
2474 };
2475
2476 #ifdef ASSERT
2477 static bool oop_offset_is_sane(const TypeInstPtr* tp) {
2478 ciInstanceKlass *k = tp->klass()->as_instance_klass();
2479 // Make sure the offset goes inside the instance layout.
2480 return k->contains_field_offset(tp->offset());
2481 // Note that OffsetBot and OffsetTop are very negative.
2482 }
2483 #endif
2484
2485 // Eliminate trivially redundant StoreCMs and accumulate their
2486 // precedence edges.
2487 void Compile::eliminate_redundant_card_marks(Node* n) {
2488 assert(n->Opcode() == Op_StoreCM, "expected StoreCM");
2489 if (n->in(MemNode::Address)->outcnt() > 1) {
2490 // There are multiple users of the same address so it might be
2491 // possible to eliminate some of the StoreCMs
2492 Node* mem = n->in(MemNode::Memory);
2493 Node* adr = n->in(MemNode::Address);
2494 Node* val = n->in(MemNode::ValueIn);
2495 Node* prev = n;
2496 bool done = false;
2497 // Walk the chain of StoreCMs eliminating ones that match. As
2498 // long as it's a chain of single users then the optimization is
2499 // safe. Eliminating partially redundant StoreCMs would require
2500 // cloning copies down the other paths.
2501 while (mem->Opcode() == Op_StoreCM && mem->outcnt() == 1 && !done) {
2502 if (adr == mem->in(MemNode::Address) &&
2503 val == mem->in(MemNode::ValueIn)) {
2504 // redundant StoreCM
2505 if (mem->req() > MemNode::OopStore) {
2506 // Hasn't been processed by this code yet.
2507 n->add_prec(mem->in(MemNode::OopStore));
2508 } else {
2509 // Already converted to precedence edge
2510 for (uint i = mem->req(); i < mem->len(); i++) {
2511 // Accumulate any precedence edges
2512 if (mem->in(i) != NULL) {
2513 n->add_prec(mem->in(i));
2514 }
2515 }
2516 // Everything above this point has been processed.
2517 done = true;
2518 }
2519 // Eliminate the previous StoreCM
2520 prev->set_req(MemNode::Memory, mem->in(MemNode::Memory));
2521 assert(mem->outcnt() == 0, "should be dead");
2522 mem->disconnect_inputs(NULL, this);
2523 } else {
2524 prev = mem;
2525 }
2526 mem = prev->in(MemNode::Memory);
2527 }
2528 }
2529 }
2530
2531 //------------------------------final_graph_reshaping_impl----------------------
2532 // Implement items 1-5 from final_graph_reshaping below.
2533 void Compile::final_graph_reshaping_impl( Node *n, Final_Reshape_Counts &frc) {
2534
2535 if ( n->outcnt() == 0 ) return; // dead node
2536 uint nop = n->Opcode();
2537
2538 // Check for 2-input instruction with "last use" on right input.
2539 // Swap to left input. Implements item (2).
2540 if( n->req() == 3 && // two-input instruction
2541 n->in(1)->outcnt() > 1 && // left use is NOT a last use
2542 (!n->in(1)->is_Phi() || n->in(1)->in(2) != n) && // it is not data loop
2543 n->in(2)->outcnt() == 1 &&// right use IS a last use
2544 !n->in(2)->is_Con() ) { // right use is not a constant
2545 // Check for commutative opcode
2546 switch( nop ) {
2547 case Op_AddI: case Op_AddF: case Op_AddD: case Op_AddL:
2548 case Op_MaxI: case Op_MinI:
2549 case Op_MulI: case Op_MulF: case Op_MulD: case Op_MulL:
2550 case Op_AndL: case Op_XorL: case Op_OrL:
2551 case Op_AndI: case Op_XorI: case Op_OrI: {
2552 // Move "last use" input to left by swapping inputs
2553 n->swap_edges(1, 2);
2554 break;
2555 }
2556 default:
2557 break;
2558 }
2559 }
2560
2561 #ifdef ASSERT
2562 if( n->is_Mem() ) {
2563 int alias_idx = get_alias_index(n->as_Mem()->adr_type());
2564 assert( n->in(0) != NULL || alias_idx != Compile::AliasIdxRaw ||
2565 // oop will be recorded in oop map if load crosses safepoint
2566 n->is_Load() && (n->as_Load()->bottom_type()->isa_oopptr() ||
2567 LoadNode::is_immutable_value(n->in(MemNode::Address))),
2568 "raw memory operations should have control edge");
2569 }
2570 #endif
2571 // Count FPU ops and common calls, implements item (3)
2572 switch( nop ) {
2573 // Count all float operations that may use FPU
2574 case Op_AddF:
2575 case Op_SubF:
2576 case Op_MulF:
2577 case Op_DivF:
2578 case Op_NegF:
2579 case Op_ModF:
2580 case Op_ConvI2F:
2581 case Op_ConF:
2582 case Op_CmpF:
2583 case Op_CmpF3:
2584 // case Op_ConvL2F: // longs are split into 32-bit halves
2585 frc.inc_float_count();
2586 break;
2587
2588 case Op_ConvF2D:
2589 case Op_ConvD2F:
2590 frc.inc_float_count();
2591 frc.inc_double_count();
2592 break;
2593
2594 // Count all double operations that may use FPU
2595 case Op_AddD:
2596 case Op_SubD:
2597 case Op_MulD:
2598 case Op_DivD:
2599 case Op_NegD:
2600 case Op_ModD:
2601 case Op_ConvI2D:
2602 case Op_ConvD2I:
2603 // case Op_ConvL2D: // handled by leaf call
2604 // case Op_ConvD2L: // handled by leaf call
2605 case Op_ConD:
2606 case Op_CmpD:
2607 case Op_CmpD3:
2608 frc.inc_double_count();
2609 break;
2610 case Op_Opaque1: // Remove Opaque Nodes before matching
2611 case Op_Opaque2: // Remove Opaque Nodes before matching
2612 case Op_Opaque3:
2613 n->subsume_by(n->in(1), this);
2614 break;
2615 case Op_CallStaticJava:
2616 case Op_CallJava:
2617 case Op_CallDynamicJava:
2618 frc.inc_java_call_count(); // Count java call site;
2619 case Op_CallRuntime:
2620 case Op_CallLeaf:
2621 case Op_CallLeafNoFP: {
2622 assert( n->is_Call(), "" );
2623 CallNode *call = n->as_Call();
2624 // Count call sites where the FP mode bit would have to be flipped.
2625 // Do not count uncommon runtime calls:
2626 // uncommon_trap, _complete_monitor_locking, _complete_monitor_unlocking,
2627 // _new_Java, _new_typeArray, _new_objArray, _rethrow_Java, ...
2628 if( !call->is_CallStaticJava() || !call->as_CallStaticJava()->_name ) {
2629 frc.inc_call_count(); // Count the call site
2630 } else { // See if uncommon argument is shared
2631 Node *n = call->in(TypeFunc::Parms);
2632 int nop = n->Opcode();
2633 // Clone shared simple arguments to uncommon calls, item (1).
2634 if( n->outcnt() > 1 &&
2635 !n->is_Proj() &&
2636 nop != Op_CreateEx &&
2637 nop != Op_CheckCastPP &&
2638 nop != Op_DecodeN &&
2639 nop != Op_DecodeNKlass &&
2640 !n->is_Mem() ) {
2641 Node *x = n->clone();
2642 call->set_req( TypeFunc::Parms, x );
2643 }
2644 }
2645 break;
2646 }
2647
2648 case Op_StoreD:
2649 case Op_LoadD:
2650 case Op_LoadD_unaligned:
2651 frc.inc_double_count();
2652 goto handle_mem;
2653 case Op_StoreF:
2654 case Op_LoadF:
2655 frc.inc_float_count();
2656 goto handle_mem;
2657
2658 case Op_StoreCM:
2659 {
2660 // Convert OopStore dependence into precedence edge
2661 Node* prec = n->in(MemNode::OopStore);
2662 n->del_req(MemNode::OopStore);
2663 n->add_prec(prec);
2664 eliminate_redundant_card_marks(n);
2665 }
2666
2667 // fall through
2668
2669 case Op_StoreB:
2670 case Op_StoreC:
2671 case Op_StorePConditional:
2672 case Op_StoreI:
2673 case Op_StoreL:
2674 case Op_StoreIConditional:
2675 case Op_StoreLConditional:
2676 case Op_CompareAndSwapI:
2677 case Op_CompareAndSwapL:
2678 case Op_CompareAndSwapP:
2679 case Op_CompareAndSwapN:
2680 case Op_GetAndAddI:
2681 case Op_GetAndAddL:
2682 case Op_GetAndSetI:
2683 case Op_GetAndSetL:
2684 case Op_GetAndSetP:
2685 case Op_GetAndSetN:
2686 case Op_StoreP:
2687 case Op_StoreN:
2688 case Op_StoreNKlass:
2689 case Op_LoadB:
2690 case Op_LoadUB:
2691 case Op_LoadUS:
2692 case Op_LoadI:
2693 case Op_LoadKlass:
2694 case Op_LoadNKlass:
2695 case Op_LoadL:
2696 case Op_LoadL_unaligned:
2697 case Op_LoadPLocked:
2698 case Op_LoadP:
2699 case Op_LoadN:
2700 case Op_LoadRange:
2701 case Op_LoadS: {
2702 handle_mem:
2703 #ifdef ASSERT
2704 if( VerifyOptoOopOffsets ) {
2705 assert( n->is_Mem(), "" );
2706 MemNode *mem = (MemNode*)n;
2707 // Check to see if address types have grounded out somehow.
2708 const TypeInstPtr *tp = mem->in(MemNode::Address)->bottom_type()->isa_instptr();
2709 assert( !tp || oop_offset_is_sane(tp), "" );
2710 }
2711 #endif
2712 break;
2713 }
2714
2715 case Op_AddP: { // Assert sane base pointers
2716 Node *addp = n->in(AddPNode::Address);
2717 assert( !addp->is_AddP() ||
2718 addp->in(AddPNode::Base)->is_top() || // Top OK for allocation
2719 addp->in(AddPNode::Base) == n->in(AddPNode::Base),
2720 "Base pointers must match" );
2721 #ifdef _LP64
2722 if ((UseCompressedOops || UseCompressedClassPointers) &&
2723 addp->Opcode() == Op_ConP &&
2724 addp == n->in(AddPNode::Base) &&
2725 n->in(AddPNode::Offset)->is_Con()) {
2726 // Use addressing with narrow klass to load with offset on x86.
2727 // On sparc loading 32-bits constant and decoding it have less
2728 // instructions (4) then load 64-bits constant (7).
2729 // Do this transformation here since IGVN will convert ConN back to ConP.
2730 const Type* t = addp->bottom_type();
2731 if (t->isa_oopptr() || t->isa_klassptr()) {
2732 Node* nn = NULL;
2733
2734 int op = t->isa_oopptr() ? Op_ConN : Op_ConNKlass;
2735
2736 // Look for existing ConN node of the same exact type.
2737 Node* r = root();
2738 uint cnt = r->outcnt();
2739 for (uint i = 0; i < cnt; i++) {
2740 Node* m = r->raw_out(i);
2741 if (m!= NULL && m->Opcode() == op &&
2742 m->bottom_type()->make_ptr() == t) {
2743 nn = m;
2744 break;
2745 }
2746 }
2747 if (nn != NULL) {
2748 // Decode a narrow oop to match address
2749 // [R12 + narrow_oop_reg<<3 + offset]
2750 if (t->isa_oopptr()) {
2751 nn = new DecodeNNode(nn, t);
2752 } else {
2753 nn = new DecodeNKlassNode(nn, t);
2754 }
2755 n->set_req(AddPNode::Base, nn);
2756 n->set_req(AddPNode::Address, nn);
2757 if (addp->outcnt() == 0) {
2758 addp->disconnect_inputs(NULL, this);
2759 }
2760 }
2761 }
2762 }
2763 #endif
2764 break;
2765 }
2766
2767 #ifdef _LP64
2768 case Op_CastPP:
2769 if (n->in(1)->is_DecodeN() && Matcher::gen_narrow_oop_implicit_null_checks()) {
2770 Node* in1 = n->in(1);
2771 const Type* t = n->bottom_type();
2772 Node* new_in1 = in1->clone();
2773 new_in1->as_DecodeN()->set_type(t);
2774
2775 if (!Matcher::narrow_oop_use_complex_address()) {
2776 //
2777 // x86, ARM and friends can handle 2 adds in addressing mode
2778 // and Matcher can fold a DecodeN node into address by using
2779 // a narrow oop directly and do implicit NULL check in address:
2780 //
2781 // [R12 + narrow_oop_reg<<3 + offset]
2782 // NullCheck narrow_oop_reg
2783 //
2784 // On other platforms (Sparc) we have to keep new DecodeN node and
2785 // use it to do implicit NULL check in address:
2786 //
2787 // decode_not_null narrow_oop_reg, base_reg
2788 // [base_reg + offset]
2789 // NullCheck base_reg
2790 //
2791 // Pin the new DecodeN node to non-null path on these platform (Sparc)
2792 // to keep the information to which NULL check the new DecodeN node
2793 // corresponds to use it as value in implicit_null_check().
2794 //
2795 new_in1->set_req(0, n->in(0));
2796 }
2797
2798 n->subsume_by(new_in1, this);
2799 if (in1->outcnt() == 0) {
2800 in1->disconnect_inputs(NULL, this);
2801 }
2802 }
2803 break;
2804
2805 case Op_CmpP:
2806 // Do this transformation here to preserve CmpPNode::sub() and
2807 // other TypePtr related Ideal optimizations (for example, ptr nullness).
2808 if (n->in(1)->is_DecodeNarrowPtr() || n->in(2)->is_DecodeNarrowPtr()) {
2809 Node* in1 = n->in(1);
2810 Node* in2 = n->in(2);
2811 if (!in1->is_DecodeNarrowPtr()) {
2812 in2 = in1;
2813 in1 = n->in(2);
2814 }
2815 assert(in1->is_DecodeNarrowPtr(), "sanity");
2816
2817 Node* new_in2 = NULL;
2818 if (in2->is_DecodeNarrowPtr()) {
2819 assert(in2->Opcode() == in1->Opcode(), "must be same node type");
2820 new_in2 = in2->in(1);
2821 } else if (in2->Opcode() == Op_ConP) {
2822 const Type* t = in2->bottom_type();
2823 if (t == TypePtr::NULL_PTR) {
2824 assert(in1->is_DecodeN(), "compare klass to null?");
2825 // Don't convert CmpP null check into CmpN if compressed
2826 // oops implicit null check is not generated.
2827 // This will allow to generate normal oop implicit null check.
2828 if (Matcher::gen_narrow_oop_implicit_null_checks())
2829 new_in2 = ConNode::make(this, TypeNarrowOop::NULL_PTR);
2830 //
2831 // This transformation together with CastPP transformation above
2832 // will generated code for implicit NULL checks for compressed oops.
2833 //
2834 // The original code after Optimize()
2835 //
2836 // LoadN memory, narrow_oop_reg
2837 // decode narrow_oop_reg, base_reg
2838 // CmpP base_reg, NULL
2839 // CastPP base_reg // NotNull
2840 // Load [base_reg + offset], val_reg
2841 //
2842 // after these transformations will be
2843 //
2844 // LoadN memory, narrow_oop_reg
2845 // CmpN narrow_oop_reg, NULL
2846 // decode_not_null narrow_oop_reg, base_reg
2847 // Load [base_reg + offset], val_reg
2848 //
2849 // and the uncommon path (== NULL) will use narrow_oop_reg directly
2850 // since narrow oops can be used in debug info now (see the code in
2851 // final_graph_reshaping_walk()).
2852 //
2853 // At the end the code will be matched to
2854 // on x86:
2855 //
2856 // Load_narrow_oop memory, narrow_oop_reg
2857 // Load [R12 + narrow_oop_reg<<3 + offset], val_reg
2858 // NullCheck narrow_oop_reg
2859 //
2860 // and on sparc:
2861 //
2862 // Load_narrow_oop memory, narrow_oop_reg
2863 // decode_not_null narrow_oop_reg, base_reg
2864 // Load [base_reg + offset], val_reg
2865 // NullCheck base_reg
2866 //
2867 } else if (t->isa_oopptr()) {
2868 new_in2 = ConNode::make(this, t->make_narrowoop());
2869 } else if (t->isa_klassptr()) {
2870 new_in2 = ConNode::make(this, t->make_narrowklass());
2871 }
2872 }
2873 if (new_in2 != NULL) {
2874 Node* cmpN = new CmpNNode(in1->in(1), new_in2);
2875 n->subsume_by(cmpN, this);
2876 if (in1->outcnt() == 0) {
2877 in1->disconnect_inputs(NULL, this);
2878 }
2879 if (in2->outcnt() == 0) {
2880 in2->disconnect_inputs(NULL, this);
2881 }
2882 }
2883 }
2884 break;
2885
2886 case Op_DecodeN:
2887 case Op_DecodeNKlass:
2888 assert(!n->in(1)->is_EncodeNarrowPtr(), "should be optimized out");
2889 // DecodeN could be pinned when it can't be fold into
2890 // an address expression, see the code for Op_CastPP above.
2891 assert(n->in(0) == NULL || (UseCompressedOops && !Matcher::narrow_oop_use_complex_address()), "no control");
2892 break;
2893
2894 case Op_EncodeP:
2895 case Op_EncodePKlass: {
2896 Node* in1 = n->in(1);
2897 if (in1->is_DecodeNarrowPtr()) {
2898 n->subsume_by(in1->in(1), this);
2899 } else if (in1->Opcode() == Op_ConP) {
2900 const Type* t = in1->bottom_type();
2901 if (t == TypePtr::NULL_PTR) {
2902 assert(t->isa_oopptr(), "null klass?");
2903 n->subsume_by(ConNode::make(this, TypeNarrowOop::NULL_PTR), this);
2904 } else if (t->isa_oopptr()) {
2905 n->subsume_by(ConNode::make(this, t->make_narrowoop()), this);
2906 } else if (t->isa_klassptr()) {
2907 n->subsume_by(ConNode::make(this, t->make_narrowklass()), this);
2908 }
2909 }
2910 if (in1->outcnt() == 0) {
2911 in1->disconnect_inputs(NULL, this);
2912 }
2913 break;
2914 }
2915
2916 case Op_Proj: {
2917 if (OptimizeStringConcat) {
2918 ProjNode* p = n->as_Proj();
2919 if (p->_is_io_use) {
2920 // Separate projections were used for the exception path which
2921 // are normally removed by a late inline. If it wasn't inlined
2922 // then they will hang around and should just be replaced with
2923 // the original one.
2924 Node* proj = NULL;
2925 // Replace with just one
2926 for (SimpleDUIterator i(p->in(0)); i.has_next(); i.next()) {
2927 Node *use = i.get();
2928 if (use->is_Proj() && p != use && use->as_Proj()->_con == p->_con) {
2929 proj = use;
2930 break;
2931 }
2932 }
2933 assert(proj != NULL, "must be found");
2934 p->subsume_by(proj, this);
2935 }
2936 }
2937 break;
2938 }
2939
2940 case Op_Phi:
2941 if (n->as_Phi()->bottom_type()->isa_narrowoop() || n->as_Phi()->bottom_type()->isa_narrowklass()) {
2942 // The EncodeP optimization may create Phi with the same edges
2943 // for all paths. It is not handled well by Register Allocator.
2944 Node* unique_in = n->in(1);
2945 assert(unique_in != NULL, "");
2946 uint cnt = n->req();
2947 for (uint i = 2; i < cnt; i++) {
2948 Node* m = n->in(i);
2949 assert(m != NULL, "");
2950 if (unique_in != m)
2951 unique_in = NULL;
2952 }
2953 if (unique_in != NULL) {
2954 n->subsume_by(unique_in, this);
2955 }
2956 }
2957 break;
2958
2959 #endif
2960
2961 case Op_ModI:
2962 if (UseDivMod) {
2963 // Check if a%b and a/b both exist
2964 Node* d = n->find_similar(Op_DivI);
2965 if (d) {
2966 // Replace them with a fused divmod if supported
2967 if (Matcher::has_match_rule(Op_DivModI)) {
2968 DivModINode* divmod = DivModINode::make(this, n);
2969 d->subsume_by(divmod->div_proj(), this);
2970 n->subsume_by(divmod->mod_proj(), this);
2971 } else {
2972 // replace a%b with a-((a/b)*b)
2973 Node* mult = new MulINode(d, d->in(2));
2974 Node* sub = new SubINode(d->in(1), mult);
2975 n->subsume_by(sub, this);
2976 }
2977 }
2978 }
2979 break;
2980
2981 case Op_ModL:
2982 if (UseDivMod) {
2983 // Check if a%b and a/b both exist
2984 Node* d = n->find_similar(Op_DivL);
2985 if (d) {
2986 // Replace them with a fused divmod if supported
2987 if (Matcher::has_match_rule(Op_DivModL)) {
2988 DivModLNode* divmod = DivModLNode::make(this, n);
2989 d->subsume_by(divmod->div_proj(), this);
2990 n->subsume_by(divmod->mod_proj(), this);
2991 } else {
2992 // replace a%b with a-((a/b)*b)
2993 Node* mult = new MulLNode(d, d->in(2));
2994 Node* sub = new SubLNode(d->in(1), mult);
2995 n->subsume_by(sub, this);
2996 }
2997 }
2998 }
2999 break;
3000
3001 case Op_LoadVector:
3002 case Op_StoreVector:
3003 break;
3004
3005 case Op_PackB:
3006 case Op_PackS:
3007 case Op_PackI:
3008 case Op_PackF:
3009 case Op_PackL:
3010 case Op_PackD:
3011 if (n->req()-1 > 2) {
3012 // Replace many operand PackNodes with a binary tree for matching
3013 PackNode* p = (PackNode*) n;
3014 Node* btp = p->binary_tree_pack(this, 1, n->req());
3015 n->subsume_by(btp, this);
3016 }
3017 break;
3018 case Op_Loop:
3019 case Op_CountedLoop:
3020 if (n->as_Loop()->is_inner_loop()) {
3021 frc.inc_inner_loop_count();
3022 }
3023 break;
3024 case Op_LShiftI:
3025 case Op_RShiftI:
3026 case Op_URShiftI:
3027 case Op_LShiftL:
3028 case Op_RShiftL:
3029 case Op_URShiftL:
3030 if (Matcher::need_masked_shift_count) {
3031 // The cpu's shift instructions don't restrict the count to the
3032 // lower 5/6 bits. We need to do the masking ourselves.
3033 Node* in2 = n->in(2);
3034 juint mask = (n->bottom_type() == TypeInt::INT) ? (BitsPerInt - 1) : (BitsPerLong - 1);
3035 const TypeInt* t = in2->find_int_type();
3036 if (t != NULL && t->is_con()) {
3037 juint shift = t->get_con();
3038 if (shift > mask) { // Unsigned cmp
3039 n->set_req(2, ConNode::make(this, TypeInt::make(shift & mask)));
3040 }
3041 } else {
3042 if (t == NULL || t->_lo < 0 || t->_hi > (int)mask) {
3043 Node* shift = new AndINode(in2, ConNode::make(this, TypeInt::make(mask)));
3044 n->set_req(2, shift);
3045 }
3046 }
3047 if (in2->outcnt() == 0) { // Remove dead node
3048 in2->disconnect_inputs(NULL, this);
3049 }
3050 }
3051 break;
3052 case Op_MemBarStoreStore:
3053 case Op_MemBarRelease:
3054 // Break the link with AllocateNode: it is no longer useful and
3055 // confuses register allocation.
3056 if (n->req() > MemBarNode::Precedent) {
3057 n->set_req(MemBarNode::Precedent, top());
3058 }
3059 break;
3060 default:
3061 assert( !n->is_Call(), "" );
3062 assert( !n->is_Mem(), "" );
3063 break;
3064 }
3065
3066 // Collect CFG split points
3067 if (n->is_MultiBranch())
3068 frc._tests.push(n);
3069 }
3070
3071 //------------------------------final_graph_reshaping_walk---------------------
3072 // Replacing Opaque nodes with their input in final_graph_reshaping_impl(),
3073 // requires that the walk visits a node's inputs before visiting the node.
3074 void Compile::final_graph_reshaping_walk( Node_Stack &nstack, Node *root, Final_Reshape_Counts &frc ) {
3075 ResourceArea *area = Thread::current()->resource_area();
3076 Unique_Node_List sfpt(area);
3077
3078 frc._visited.set(root->_idx); // first, mark node as visited
3079 uint cnt = root->req();
3080 Node *n = root;
3081 uint i = 0;
3082 while (true) {
3083 if (i < cnt) {
3084 // Place all non-visited non-null inputs onto stack
3085 Node* m = n->in(i);
3086 ++i;
3087 if (m != NULL && !frc._visited.test_set(m->_idx)) {
3088 if (m->is_SafePoint() && m->as_SafePoint()->jvms() != NULL) {
3089 // compute worst case interpreter size in case of a deoptimization
3090 update_interpreter_frame_size(m->as_SafePoint()->jvms()->interpreter_frame_size());
3091
3092 sfpt.push(m);
3093 }
3094 cnt = m->req();
3095 nstack.push(n, i); // put on stack parent and next input's index
3096 n = m;
3097 i = 0;
3098 }
3099 } else {
3100 // Now do post-visit work
3101 final_graph_reshaping_impl( n, frc );
3102 if (nstack.is_empty())
3103 break; // finished
3104 n = nstack.node(); // Get node from stack
3105 cnt = n->req();
3106 i = nstack.index();
3107 nstack.pop(); // Shift to the next node on stack
3108 }
3109 }
3110
3111 // Skip next transformation if compressed oops are not used.
3112 if ((UseCompressedOops && !Matcher::gen_narrow_oop_implicit_null_checks()) ||
3113 (!UseCompressedOops && !UseCompressedClassPointers))
3114 return;
3115
3116 // Go over safepoints nodes to skip DecodeN/DecodeNKlass nodes for debug edges.
3117 // It could be done for an uncommon traps or any safepoints/calls
3118 // if the DecodeN/DecodeNKlass node is referenced only in a debug info.
3119 while (sfpt.size() > 0) {
3120 n = sfpt.pop();
3121 JVMState *jvms = n->as_SafePoint()->jvms();
3122 assert(jvms != NULL, "sanity");
3123 int start = jvms->debug_start();
3124 int end = n->req();
3125 bool is_uncommon = (n->is_CallStaticJava() &&
3126 n->as_CallStaticJava()->uncommon_trap_request() != 0);
3127 for (int j = start; j < end; j++) {
3128 Node* in = n->in(j);
3129 if (in->is_DecodeNarrowPtr()) {
3130 bool safe_to_skip = true;
3131 if (!is_uncommon ) {
3132 // Is it safe to skip?
3133 for (uint i = 0; i < in->outcnt(); i++) {
3134 Node* u = in->raw_out(i);
3135 if (!u->is_SafePoint() ||
3136 u->is_Call() && u->as_Call()->has_non_debug_use(n)) {
3137 safe_to_skip = false;
3138 }
3139 }
3140 }
3141 if (safe_to_skip) {
3142 n->set_req(j, in->in(1));
3143 }
3144 if (in->outcnt() == 0) {
3145 in->disconnect_inputs(NULL, this);
3146 }
3147 }
3148 }
3149 }
3150 }
3151
3152 //------------------------------final_graph_reshaping--------------------------
3153 // Final Graph Reshaping.
3154 //
3155 // (1) Clone simple inputs to uncommon calls, so they can be scheduled late
3156 // and not commoned up and forced early. Must come after regular
3157 // optimizations to avoid GVN undoing the cloning. Clone constant
3158 // inputs to Loop Phis; these will be split by the allocator anyways.
3159 // Remove Opaque nodes.
3160 // (2) Move last-uses by commutative operations to the left input to encourage
3161 // Intel update-in-place two-address operations and better register usage
3162 // on RISCs. Must come after regular optimizations to avoid GVN Ideal
3163 // calls canonicalizing them back.
3164 // (3) Count the number of double-precision FP ops, single-precision FP ops
3165 // and call sites. On Intel, we can get correct rounding either by
3166 // forcing singles to memory (requires extra stores and loads after each
3167 // FP bytecode) or we can set a rounding mode bit (requires setting and
3168 // clearing the mode bit around call sites). The mode bit is only used
3169 // if the relative frequency of single FP ops to calls is low enough.
3170 // This is a key transform for SPEC mpeg_audio.
3171 // (4) Detect infinite loops; blobs of code reachable from above but not
3172 // below. Several of the Code_Gen algorithms fail on such code shapes,
3173 // so we simply bail out. Happens a lot in ZKM.jar, but also happens
3174 // from time to time in other codes (such as -Xcomp finalizer loops, etc).
3175 // Detection is by looking for IfNodes where only 1 projection is
3176 // reachable from below or CatchNodes missing some targets.
3177 // (5) Assert for insane oop offsets in debug mode.
3178
3179 bool Compile::final_graph_reshaping() {
3180 // an infinite loop may have been eliminated by the optimizer,
3181 // in which case the graph will be empty.
3182 if (root()->req() == 1) {
3183 record_method_not_compilable("trivial infinite loop");
3184 return true;
3185 }
3186
3187 // Expensive nodes have their control input set to prevent the GVN
3188 // from freely commoning them. There's no GVN beyond this point so
3189 // no need to keep the control input. We want the expensive nodes to
3190 // be freely moved to the least frequent code path by gcm.
3191 assert(OptimizeExpensiveOps || expensive_count() == 0, "optimization off but list non empty?");
3192 for (int i = 0; i < expensive_count(); i++) {
3193 _expensive_nodes->at(i)->set_req(0, NULL);
3194 }
3195
3196 Final_Reshape_Counts frc;
3197
3198 // Visit everybody reachable!
3199 // Allocate stack of size C->unique()/2 to avoid frequent realloc
3200 Node_Stack nstack(unique() >> 1);
3201 final_graph_reshaping_walk(nstack, root(), frc);
3202
3203 // Check for unreachable (from below) code (i.e., infinite loops).
3204 for( uint i = 0; i < frc._tests.size(); i++ ) {
3205 MultiBranchNode *n = frc._tests[i]->as_MultiBranch();
3206 // Get number of CFG targets.
3207 // Note that PCTables include exception targets after calls.
3208 uint required_outcnt = n->required_outcnt();
3209 if (n->outcnt() != required_outcnt) {
3210 // Check for a few special cases. Rethrow Nodes never take the
3211 // 'fall-thru' path, so expected kids is 1 less.
3212 if (n->is_PCTable() && n->in(0) && n->in(0)->in(0)) {
3213 if (n->in(0)->in(0)->is_Call()) {
3214 CallNode *call = n->in(0)->in(0)->as_Call();
3215 if (call->entry_point() == OptoRuntime::rethrow_stub()) {
3216 required_outcnt--; // Rethrow always has 1 less kid
3217 } else if (call->req() > TypeFunc::Parms &&
3218 call->is_CallDynamicJava()) {
3219 // Check for null receiver. In such case, the optimizer has
3220 // detected that the virtual call will always result in a null
3221 // pointer exception. The fall-through projection of this CatchNode
3222 // will not be populated.
3223 Node *arg0 = call->in(TypeFunc::Parms);
3224 if (arg0->is_Type() &&
3225 arg0->as_Type()->type()->higher_equal(TypePtr::NULL_PTR)) {
3226 required_outcnt--;
3227 }
3228 } else if (call->entry_point() == OptoRuntime::new_array_Java() &&
3229 call->req() > TypeFunc::Parms+1 &&
3230 call->is_CallStaticJava()) {
3231 // Check for negative array length. In such case, the optimizer has
3232 // detected that the allocation attempt will always result in an
3233 // exception. There is no fall-through projection of this CatchNode .
3234 Node *arg1 = call->in(TypeFunc::Parms+1);
3235 if (arg1->is_Type() &&
3236 arg1->as_Type()->type()->join(TypeInt::POS)->empty()) {
3237 required_outcnt--;
3238 }
3239 }
3240 }
3241 }
3242 // Recheck with a better notion of 'required_outcnt'
3243 if (n->outcnt() != required_outcnt) {
3244 record_method_not_compilable("malformed control flow");
3245 return true; // Not all targets reachable!
3246 }
3247 }
3248 // Check that I actually visited all kids. Unreached kids
3249 // must be infinite loops.
3250 for (DUIterator_Fast jmax, j = n->fast_outs(jmax); j < jmax; j++)
3251 if (!frc._visited.test(n->fast_out(j)->_idx)) {
3252 record_method_not_compilable("infinite loop");
3253 return true; // Found unvisited kid; must be unreach
3254 }
3255 }
3256
3257 // If original bytecodes contained a mixture of floats and doubles
3258 // check if the optimizer has made it homogenous, item (3).
3259 if( Use24BitFPMode && Use24BitFP && UseSSE == 0 &&
3260 frc.get_float_count() > 32 &&
3261 frc.get_double_count() == 0 &&
3262 (10 * frc.get_call_count() < frc.get_float_count()) ) {
3263 set_24_bit_selection_and_mode( false, true );
3264 }
3265
3266 set_java_calls(frc.get_java_call_count());
3267 set_inner_loops(frc.get_inner_loop_count());
3268
3269 // No infinite loops, no reason to bail out.
3270 return false;
3271 }
3272
3273 //-----------------------------too_many_traps----------------------------------
3274 // Report if there are too many traps at the current method and bci.
3275 // Return true if there was a trap, and/or PerMethodTrapLimit is exceeded.
3276 bool Compile::too_many_traps(ciMethod* method,
3277 int bci,
3278 Deoptimization::DeoptReason reason) {
3279 ciMethodData* md = method->method_data();
3280 if (md->is_empty()) {
3281 // Assume the trap has not occurred, or that it occurred only
3282 // because of a transient condition during start-up in the interpreter.
3283 return false;
3284 }
3285 ciMethod* m = Deoptimization::reason_is_speculate(reason) ? this->method() : NULL;
3286 if (md->has_trap_at(bci, m, reason) != 0) {
3287 // Assume PerBytecodeTrapLimit==0, for a more conservative heuristic.
3288 // Also, if there are multiple reasons, or if there is no per-BCI record,
3289 // assume the worst.
3290 if (log())
3291 log()->elem("observe trap='%s' count='%d'",
3292 Deoptimization::trap_reason_name(reason),
3293 md->trap_count(reason));
3294 return true;
3295 } else {
3296 // Ignore method/bci and see if there have been too many globally.
3297 return too_many_traps(reason, md);
3298 }
3299 }
3300
3301 // Less-accurate variant which does not require a method and bci.
3302 bool Compile::too_many_traps(Deoptimization::DeoptReason reason,
3303 ciMethodData* logmd) {
3304 if (trap_count(reason) >= Deoptimization::per_method_trap_limit(reason)) {
3305 // Too many traps globally.
3306 // Note that we use cumulative trap_count, not just md->trap_count.
3307 if (log()) {
3308 int mcount = (logmd == NULL)? -1: (int)logmd->trap_count(reason);
3309 log()->elem("observe trap='%s' count='0' mcount='%d' ccount='%d'",
3310 Deoptimization::trap_reason_name(reason),
3311 mcount, trap_count(reason));
3312 }
3313 return true;
3314 } else {
3315 // The coast is clear.
3316 return false;
3317 }
3318 }
3319
3320 //--------------------------too_many_recompiles--------------------------------
3321 // Report if there are too many recompiles at the current method and bci.
3322 // Consults PerBytecodeRecompilationCutoff and PerMethodRecompilationCutoff.
3323 // Is not eager to return true, since this will cause the compiler to use
3324 // Action_none for a trap point, to avoid too many recompilations.
3325 bool Compile::too_many_recompiles(ciMethod* method,
3326 int bci,
3327 Deoptimization::DeoptReason reason) {
3328 ciMethodData* md = method->method_data();
3329 if (md->is_empty()) {
3330 // Assume the trap has not occurred, or that it occurred only
3331 // because of a transient condition during start-up in the interpreter.
3332 return false;
3333 }
3334 // Pick a cutoff point well within PerBytecodeRecompilationCutoff.
3335 uint bc_cutoff = (uint) PerBytecodeRecompilationCutoff / 8;
3336 uint m_cutoff = (uint) PerMethodRecompilationCutoff / 2 + 1; // not zero
3337 Deoptimization::DeoptReason per_bc_reason
3338 = Deoptimization::reason_recorded_per_bytecode_if_any(reason);
3339 ciMethod* m = Deoptimization::reason_is_speculate(reason) ? this->method() : NULL;
3340 if ((per_bc_reason == Deoptimization::Reason_none
3341 || md->has_trap_at(bci, m, reason) != 0)
3342 // The trap frequency measure we care about is the recompile count:
3343 && md->trap_recompiled_at(bci, m)
3344 && md->overflow_recompile_count() >= bc_cutoff) {
3345 // Do not emit a trap here if it has already caused recompilations.
3346 // Also, if there are multiple reasons, or if there is no per-BCI record,
3347 // assume the worst.
3348 if (log())
3349 log()->elem("observe trap='%s recompiled' count='%d' recompiles2='%d'",
3350 Deoptimization::trap_reason_name(reason),
3351 md->trap_count(reason),
3352 md->overflow_recompile_count());
3353 return true;
3354 } else if (trap_count(reason) != 0
3355 && decompile_count() >= m_cutoff) {
3356 // Too many recompiles globally, and we have seen this sort of trap.
3357 // Use cumulative decompile_count, not just md->decompile_count.
3358 if (log())
3359 log()->elem("observe trap='%s' count='%d' mcount='%d' decompiles='%d' mdecompiles='%d'",
3360 Deoptimization::trap_reason_name(reason),
3361 md->trap_count(reason), trap_count(reason),
3362 md->decompile_count(), decompile_count());
3363 return true;
3364 } else {
3365 // The coast is clear.
3366 return false;
3367 }
3368 }
3369
3370 // Compute when not to trap. Used by matching trap based nodes and
3371 // NullCheck optimization.
3372 void Compile::set_allowed_deopt_reasons() {
3373 _allowed_reasons = 0;
3374 if (is_method_compilation()) {
3375 for (int rs = (int)Deoptimization::Reason_none+1; rs < Compile::trapHistLength; rs++) {
3376 assert(rs < BitsPerInt, "recode bit map");
3377 if (!too_many_traps((Deoptimization::DeoptReason) rs)) {
3378 _allowed_reasons |= nth_bit(rs);
3379 }
3380 }
3381 }
3382 }
3383
3384 #ifndef PRODUCT
3385 //------------------------------verify_graph_edges---------------------------
3386 // Walk the Graph and verify that there is a one-to-one correspondence
3387 // between Use-Def edges and Def-Use edges in the graph.
3388 void Compile::verify_graph_edges(bool no_dead_code) {
3389 if (VerifyGraphEdges) {
3390 ResourceArea *area = Thread::current()->resource_area();
3391 Unique_Node_List visited(area);
3392 // Call recursive graph walk to check edges
3393 _root->verify_edges(visited);
3394 if (no_dead_code) {
3395 // Now make sure that no visited node is used by an unvisited node.
3396 bool dead_nodes = false;
3397 Unique_Node_List checked(area);
3398 while (visited.size() > 0) {
3399 Node* n = visited.pop();
3400 checked.push(n);
3401 for (uint i = 0; i < n->outcnt(); i++) {
3402 Node* use = n->raw_out(i);
3403 if (checked.member(use)) continue; // already checked
3404 if (visited.member(use)) continue; // already in the graph
3405 if (use->is_Con()) continue; // a dead ConNode is OK
3406 // At this point, we have found a dead node which is DU-reachable.
3407 if (!dead_nodes) {
3408 tty->print_cr("*** Dead nodes reachable via DU edges:");
3409 dead_nodes = true;
3410 }
3411 use->dump(2);
3412 tty->print_cr("---");
3413 checked.push(use); // No repeats; pretend it is now checked.
3414 }
3415 }
3416 assert(!dead_nodes, "using nodes must be reachable from root");
3417 }
3418 }
3419 }
3420
3421 // Verify GC barriers consistency
3422 // Currently supported:
3423 // - G1 pre-barriers (see GraphKit::g1_write_barrier_pre())
3424 void Compile::verify_barriers() {
3425 if (UseG1GC) {
3426 // Verify G1 pre-barriers
3427 const int marking_offset = in_bytes(JavaThread::satb_mark_queue_offset() + PtrQueue::byte_offset_of_active());
3428
3429 ResourceArea *area = Thread::current()->resource_area();
3430 Unique_Node_List visited(area);
3431 Node_List worklist(area);
3432 // We're going to walk control flow backwards starting from the Root
3433 worklist.push(_root);
3434 while (worklist.size() > 0) {
3435 Node* x = worklist.pop();
3436 if (x == NULL || x == top()) continue;
3437 if (visited.member(x)) {
3438 continue;
3439 } else {
3440 visited.push(x);
3441 }
3442
3443 if (x->is_Region()) {
3444 for (uint i = 1; i < x->req(); i++) {
3445 worklist.push(x->in(i));
3446 }
3447 } else {
3448 worklist.push(x->in(0));
3449 // We are looking for the pattern:
3450 // /->ThreadLocal
3451 // If->Bool->CmpI->LoadB->AddP->ConL(marking_offset)
3452 // \->ConI(0)
3453 // We want to verify that the If and the LoadB have the same control
3454 // See GraphKit::g1_write_barrier_pre()
3455 if (x->is_If()) {
3456 IfNode *iff = x->as_If();
3457 if (iff->in(1)->is_Bool() && iff->in(1)->in(1)->is_Cmp()) {
3458 CmpNode *cmp = iff->in(1)->in(1)->as_Cmp();
3459 if (cmp->Opcode() == Op_CmpI && cmp->in(2)->is_Con() && cmp->in(2)->bottom_type()->is_int()->get_con() == 0
3460 && cmp->in(1)->is_Load()) {
3461 LoadNode* load = cmp->in(1)->as_Load();
3462 if (load->Opcode() == Op_LoadB && load->in(2)->is_AddP() && load->in(2)->in(2)->Opcode() == Op_ThreadLocal
3463 && load->in(2)->in(3)->is_Con()
3464 && load->in(2)->in(3)->bottom_type()->is_intptr_t()->get_con() == marking_offset) {
3465
3466 Node* if_ctrl = iff->in(0);
3467 Node* load_ctrl = load->in(0);
3468
3469 if (if_ctrl != load_ctrl) {
3470 // Skip possible CProj->NeverBranch in infinite loops
3471 if ((if_ctrl->is_Proj() && if_ctrl->Opcode() == Op_CProj)
3472 && (if_ctrl->in(0)->is_MultiBranch() && if_ctrl->in(0)->Opcode() == Op_NeverBranch)) {
3473 if_ctrl = if_ctrl->in(0)->in(0);
3474 }
3475 }
3476 assert(load_ctrl != NULL && if_ctrl == load_ctrl, "controls must match");
3477 }
3478 }
3479 }
3480 }
3481 }
3482 }
3483 }
3484 }
3485
3486 #endif
3487
3488 // The Compile object keeps track of failure reasons separately from the ciEnv.
3489 // This is required because there is not quite a 1-1 relation between the
3490 // ciEnv and its compilation task and the Compile object. Note that one
3491 // ciEnv might use two Compile objects, if C2Compiler::compile_method decides
3492 // to backtrack and retry without subsuming loads. Other than this backtracking
3493 // behavior, the Compile's failure reason is quietly copied up to the ciEnv
3494 // by the logic in C2Compiler.
3495 void Compile::record_failure(const char* reason) {
3496 if (log() != NULL) {
3497 log()->elem("failure reason='%s' phase='compile'", reason);
3498 }
3499 if (_failure_reason == NULL) {
3500 // Record the first failure reason.
3501 _failure_reason = reason;
3502 }
3503
3504 EventCompilerFailure event;
3505 if (event.should_commit()) {
3506 event.set_compileID(Compile::compile_id());
3507 event.set_failure(reason);
3508 event.commit();
3509 }
3510
3511 if (!C->failure_reason_is(C2Compiler::retry_no_subsuming_loads())) {
3512 C->print_method(PHASE_FAILURE);
3513 }
3514 _root = NULL; // flush the graph, too
3515 }
3516
3517 Compile::TracePhase::TracePhase(const char* name, elapsedTimer* accumulator, bool dolog)
3518 : TraceTime(NULL, accumulator, false NOT_PRODUCT( || TimeCompiler ), false),
3519 _phase_name(name), _dolog(dolog)
3520 {
3521 if (dolog) {
3522 C = Compile::current();
3523 _log = C->log();
3524 } else {
3525 C = NULL;
3526 _log = NULL;
3527 }
3528 if (_log != NULL) {
3529 _log->begin_head("phase name='%s' nodes='%d' live='%d'", _phase_name, C->unique(), C->live_nodes());
3530 _log->stamp();
3531 _log->end_head();
3532 }
3533 }
3534
3535 Compile::TracePhase::~TracePhase() {
3536
3537 C = Compile::current();
3538 if (_dolog) {
3539 _log = C->log();
3540 } else {
3541 _log = NULL;
3542 }
3543
3544 #ifdef ASSERT
3545 if (PrintIdealNodeCount) {
3546 tty->print_cr("phase name='%s' nodes='%d' live='%d' live_graph_walk='%d'",
3547 _phase_name, C->unique(), C->live_nodes(), C->count_live_nodes_by_graph_walk());
3548 }
3549
3550 if (VerifyIdealNodeCount) {
3551 Compile::current()->print_missing_nodes();
3552 }
3553 #endif
3554
3555 if (_log != NULL) {
3556 _log->done("phase name='%s' nodes='%d' live='%d'", _phase_name, C->unique(), C->live_nodes());
3557 }
3558 }
3559
3560 //=============================================================================
3561 // Two Constant's are equal when the type and the value are equal.
3562 bool Compile::Constant::operator==(const Constant& other) {
3563 if (type() != other.type() ) return false;
3564 if (can_be_reused() != other.can_be_reused()) return false;
3565 // For floating point values we compare the bit pattern.
3566 switch (type()) {
3567 case T_FLOAT: return (_v._value.i == other._v._value.i);
3568 case T_LONG:
3569 case T_DOUBLE: return (_v._value.j == other._v._value.j);
3570 case T_OBJECT:
3571 case T_ADDRESS: return (_v._value.l == other._v._value.l);
3572 case T_VOID: return (_v._value.l == other._v._value.l); // jump-table entries
3573 case T_METADATA: return (_v._metadata == other._v._metadata);
3574 default: ShouldNotReachHere();
3575 }
3576 return false;
3577 }
3578
3579 static int type_to_size_in_bytes(BasicType t) {
3580 switch (t) {
3581 case T_LONG: return sizeof(jlong );
3582 case T_FLOAT: return sizeof(jfloat );
3583 case T_DOUBLE: return sizeof(jdouble);
3584 case T_METADATA: return sizeof(Metadata*);
3585 // We use T_VOID as marker for jump-table entries (labels) which
3586 // need an internal word relocation.
3587 case T_VOID:
3588 case T_ADDRESS:
3589 case T_OBJECT: return sizeof(jobject);
3590 }
3591
3592 ShouldNotReachHere();
3593 return -1;
3594 }
3595
3596 int Compile::ConstantTable::qsort_comparator(Constant* a, Constant* b) {
3597 // sort descending
3598 if (a->freq() > b->freq()) return -1;
3599 if (a->freq() < b->freq()) return 1;
3600 return 0;
3601 }
3602
3603 void Compile::ConstantTable::calculate_offsets_and_size() {
3604 // First, sort the array by frequencies.
3605 _constants.sort(qsort_comparator);
3606
3607 #ifdef ASSERT
3608 // Make sure all jump-table entries were sorted to the end of the
3609 // array (they have a negative frequency).
3610 bool found_void = false;
3611 for (int i = 0; i < _constants.length(); i++) {
3612 Constant con = _constants.at(i);
3613 if (con.type() == T_VOID)
3614 found_void = true; // jump-tables
3615 else
3616 assert(!found_void, "wrong sorting");
3617 }
3618 #endif
3619
3620 int offset = 0;
3621 for (int i = 0; i < _constants.length(); i++) {
3622 Constant* con = _constants.adr_at(i);
3623
3624 // Align offset for type.
3625 int typesize = type_to_size_in_bytes(con->type());
3626 offset = align_size_up(offset, typesize);
3627 con->set_offset(offset); // set constant's offset
3628
3629 if (con->type() == T_VOID) {
3630 MachConstantNode* n = (MachConstantNode*) con->get_jobject();
3631 offset = offset + typesize * n->outcnt(); // expand jump-table
3632 } else {
3633 offset = offset + typesize;
3634 }
3635 }
3636
3637 // Align size up to the next section start (which is insts; see
3638 // CodeBuffer::align_at_start).
3639 assert(_size == -1, "already set?");
3640 _size = align_size_up(offset, CodeEntryAlignment);
3641 }
3642
3643 void Compile::ConstantTable::emit(CodeBuffer& cb) {
3644 MacroAssembler _masm(&cb);
3645 for (int i = 0; i < _constants.length(); i++) {
3646 Constant con = _constants.at(i);
3647 address constant_addr;
3648 switch (con.type()) {
3649 case T_LONG: constant_addr = _masm.long_constant( con.get_jlong() ); break;
3650 case T_FLOAT: constant_addr = _masm.float_constant( con.get_jfloat() ); break;
3651 case T_DOUBLE: constant_addr = _masm.double_constant(con.get_jdouble()); break;
3652 case T_OBJECT: {
3653 jobject obj = con.get_jobject();
3654 int oop_index = _masm.oop_recorder()->find_index(obj);
3655 constant_addr = _masm.address_constant((address) obj, oop_Relocation::spec(oop_index));
3656 break;
3657 }
3658 case T_ADDRESS: {
3659 address addr = (address) con.get_jobject();
3660 constant_addr = _masm.address_constant(addr);
3661 break;
3662 }
3663 // We use T_VOID as marker for jump-table entries (labels) which
3664 // need an internal word relocation.
3665 case T_VOID: {
3666 MachConstantNode* n = (MachConstantNode*) con.get_jobject();
3667 // Fill the jump-table with a dummy word. The real value is
3668 // filled in later in fill_jump_table.
3669 address dummy = (address) n;
3670 constant_addr = _masm.address_constant(dummy);
3671 // Expand jump-table
3672 for (uint i = 1; i < n->outcnt(); i++) {
3673 address temp_addr = _masm.address_constant(dummy + i);
3674 assert(temp_addr, "consts section too small");
3675 }
3676 break;
3677 }
3678 case T_METADATA: {
3679 Metadata* obj = con.get_metadata();
3680 int metadata_index = _masm.oop_recorder()->find_index(obj);
3681 constant_addr = _masm.address_constant((address) obj, metadata_Relocation::spec(metadata_index));
3682 break;
3683 }
3684 default: ShouldNotReachHere();
3685 }
3686 assert(constant_addr, "consts section too small");
3687 assert((constant_addr - _masm.code()->consts()->start()) == con.offset(),
3688 err_msg_res("must be: %d == %d", (int) (constant_addr - _masm.code()->consts()->start()), (int)(con.offset())));
3689 }
3690 }
3691
3692 int Compile::ConstantTable::find_offset(Constant& con) const {
3693 int idx = _constants.find(con);
3694 assert(idx != -1, "constant must be in constant table");
3695 int offset = _constants.at(idx).offset();
3696 assert(offset != -1, "constant table not emitted yet?");
3697 return offset;
3698 }
3699
3700 void Compile::ConstantTable::add(Constant& con) {
3701 if (con.can_be_reused()) {
3702 int idx = _constants.find(con);
3703 if (idx != -1 && _constants.at(idx).can_be_reused()) {
3704 _constants.adr_at(idx)->inc_freq(con.freq()); // increase the frequency by the current value
3705 return;
3706 }
3707 }
3708 (void) _constants.append(con);
3709 }
3710
3711 Compile::Constant Compile::ConstantTable::add(MachConstantNode* n, BasicType type, jvalue value) {
3712 Block* b = Compile::current()->cfg()->get_block_for_node(n);
3713 Constant con(type, value, b->_freq);
3714 add(con);
3715 return con;
3716 }
3717
3718 Compile::Constant Compile::ConstantTable::add(Metadata* metadata) {
3719 Constant con(metadata);
3720 add(con);
3721 return con;
3722 }
3723
3724 Compile::Constant Compile::ConstantTable::add(MachConstantNode* n, MachOper* oper) {
3725 jvalue value;
3726 BasicType type = oper->type()->basic_type();
3727 switch (type) {
3728 case T_LONG: value.j = oper->constantL(); break;
3729 case T_FLOAT: value.f = oper->constantF(); break;
3730 case T_DOUBLE: value.d = oper->constantD(); break;
3731 case T_OBJECT:
3732 case T_ADDRESS: value.l = (jobject) oper->constant(); break;
3733 case T_METADATA: return add((Metadata*)oper->constant()); break;
3734 default: guarantee(false, err_msg_res("unhandled type: %s", type2name(type)));
3735 }
3736 return add(n, type, value);
3737 }
3738
3739 Compile::Constant Compile::ConstantTable::add_jump_table(MachConstantNode* n) {
3740 jvalue value;
3741 // We can use the node pointer here to identify the right jump-table
3742 // as this method is called from Compile::Fill_buffer right before
3743 // the MachNodes are emitted and the jump-table is filled (means the
3744 // MachNode pointers do not change anymore).
3745 value.l = (jobject) n;
3746 Constant con(T_VOID, value, next_jump_table_freq(), false); // Labels of a jump-table cannot be reused.
3747 add(con);
3748 return con;
3749 }
3750
3751 void Compile::ConstantTable::fill_jump_table(CodeBuffer& cb, MachConstantNode* n, GrowableArray<Label*> labels) const {
3752 // If called from Compile::scratch_emit_size do nothing.
3753 if (Compile::current()->in_scratch_emit_size()) return;
3754
3755 assert(labels.is_nonempty(), "must be");
3756 assert((uint) labels.length() == n->outcnt(), err_msg_res("must be equal: %d == %d", labels.length(), n->outcnt()));
3757
3758 // Since MachConstantNode::constant_offset() also contains
3759 // table_base_offset() we need to subtract the table_base_offset()
3760 // to get the plain offset into the constant table.
3761 int offset = n->constant_offset() - table_base_offset();
3762
3763 MacroAssembler _masm(&cb);
3764 address* jump_table_base = (address*) (_masm.code()->consts()->start() + offset);
3765
3766 for (uint i = 0; i < n->outcnt(); i++) {
3767 address* constant_addr = &jump_table_base[i];
3768 assert(*constant_addr == (((address) n) + i), err_msg_res("all jump-table entries must contain adjusted node pointer: " INTPTR_FORMAT " == " INTPTR_FORMAT, p2i(*constant_addr), p2i(((address) n) + i)));
3769 *constant_addr = cb.consts()->target(*labels.at(i), (address) constant_addr);
3770 cb.consts()->relocate((address) constant_addr, relocInfo::internal_word_type);
3771 }
3772 }
3773
3774 // The message about the current inlining is accumulated in
3775 // _print_inlining_stream and transfered into the _print_inlining_list
3776 // once we know whether inlining succeeds or not. For regular
3777 // inlining, messages are appended to the buffer pointed by
3778 // _print_inlining_idx in the _print_inlining_list. For late inlining,
3779 // a new buffer is added after _print_inlining_idx in the list. This
3780 // way we can update the inlining message for late inlining call site
3781 // when the inlining is attempted again.
3782 void Compile::print_inlining_init() {
3783 if (print_inlining() || print_intrinsics()) {
3784 _print_inlining_stream = new stringStream();
3785 _print_inlining_list = new (comp_arena())GrowableArray<PrintInliningBuffer>(comp_arena(), 1, 1, PrintInliningBuffer());
3786 }
3787 }
3788
3789 void Compile::print_inlining_reinit() {
3790 if (print_inlining() || print_intrinsics()) {
3791 // Re allocate buffer when we change ResourceMark
3792 _print_inlining_stream = new stringStream();
3793 }
3794 }
3795
3796 void Compile::print_inlining_reset() {
3797 _print_inlining_stream->reset();
3798 }
3799
3800 void Compile::print_inlining_commit() {
3801 assert(print_inlining() || print_intrinsics(), "PrintInlining off?");
3802 // Transfer the message from _print_inlining_stream to the current
3803 // _print_inlining_list buffer and clear _print_inlining_stream.
3804 _print_inlining_list->at(_print_inlining_idx).ss()->write(_print_inlining_stream->as_string(), _print_inlining_stream->size());
3805 print_inlining_reset();
3806 }
3807
3808 void Compile::print_inlining_push() {
3809 // Add new buffer to the _print_inlining_list at current position
3810 _print_inlining_idx++;
3811 _print_inlining_list->insert_before(_print_inlining_idx, PrintInliningBuffer());
3812 }
3813
3814 Compile::PrintInliningBuffer& Compile::print_inlining_current() {
3815 return _print_inlining_list->at(_print_inlining_idx);
3816 }
3817
3818 void Compile::print_inlining_update(CallGenerator* cg) {
3819 if (print_inlining() || print_intrinsics()) {
3820 if (!cg->is_late_inline()) {
3821 if (print_inlining_current().cg() != NULL) {
3822 print_inlining_push();
3823 }
3824 print_inlining_commit();
3825 } else {
3826 if (print_inlining_current().cg() != cg &&
3827 (print_inlining_current().cg() != NULL ||
3828 print_inlining_current().ss()->size() != 0)) {
3829 print_inlining_push();
3830 }
3831 print_inlining_commit();
3832 print_inlining_current().set_cg(cg);
3833 }
3834 }
3835 }
3836
3837 void Compile::print_inlining_move_to(CallGenerator* cg) {
3838 // We resume inlining at a late inlining call site. Locate the
3839 // corresponding inlining buffer so that we can update it.
3840 if (print_inlining()) {
3841 for (int i = 0; i < _print_inlining_list->length(); i++) {
3842 if (_print_inlining_list->adr_at(i)->cg() == cg) {
3843 _print_inlining_idx = i;
3844 return;
3845 }
3846 }
3847 ShouldNotReachHere();
3848 }
3849 }
3850
3851 void Compile::print_inlining_update_delayed(CallGenerator* cg) {
3852 if (print_inlining()) {
3853 assert(_print_inlining_stream->size() > 0, "missing inlining msg");
3854 assert(print_inlining_current().cg() == cg, "wrong entry");
3855 // replace message with new message
3856 _print_inlining_list->at_put(_print_inlining_idx, PrintInliningBuffer());
3857 print_inlining_commit();
3858 print_inlining_current().set_cg(cg);
3859 }
3860 }
3861
3862 void Compile::print_inlining_assert_ready() {
3863 assert(!_print_inlining || _print_inlining_stream->size() == 0, "loosing data");
3864 }
3865
3866 void Compile::process_print_inlining() {
3867 bool do_print_inlining = print_inlining() || print_intrinsics();
3868 if (do_print_inlining || log() != NULL) {
3869 // Print inlining message for candidates that we couldn't inline
3870 // for lack of space
3871 for (int i = 0; i < _late_inlines.length(); i++) {
3872 CallGenerator* cg = _late_inlines.at(i);
3873 if (!cg->is_mh_late_inline()) {
3874 const char* msg = "live nodes > LiveNodeCountInliningCutoff";
3875 if (do_print_inlining) {
3876 cg->print_inlining_late(msg);
3877 }
3878 log_late_inline_failure(cg, msg);
3879 }
3880 }
3881 }
3882 if (do_print_inlining) {
3883 ResourceMark rm;
3884 stringStream ss;
3885 for (int i = 0; i < _print_inlining_list->length(); i++) {
3886 ss.print("%s", _print_inlining_list->adr_at(i)->ss()->as_string());
3887 }
3888 size_t end = ss.size();
3889 _print_inlining_output = NEW_ARENA_ARRAY(comp_arena(), char, end+1);
3890 strncpy(_print_inlining_output, ss.base(), end+1);
3891 _print_inlining_output[end] = 0;
3892 }
3893 }
3894
3895 void Compile::dump_print_inlining() {
3896 if (_print_inlining_output != NULL) {
3897 tty->print_raw(_print_inlining_output);
3898 }
3899 }
3900
3901 void Compile::log_late_inline(CallGenerator* cg) {
3902 if (log() != NULL) {
3903 log()->head("late_inline method='%d' inline_id='" JLONG_FORMAT "'", log()->identify(cg->method()),
3904 cg->unique_id());
3905 JVMState* p = cg->call_node()->jvms();
3906 while (p != NULL) {
3907 log()->elem("jvms bci='%d' method='%d'", p->bci(), log()->identify(p->method()));
3908 p = p->caller();
3909 }
3910 log()->tail("late_inline");
3911 }
3912 }
3913
3914 void Compile::log_late_inline_failure(CallGenerator* cg, const char* msg) {
3915 log_late_inline(cg);
3916 if (log() != NULL) {
3917 log()->inline_fail(msg);
3918 }
3919 }
3920
3921 void Compile::log_inline_id(CallGenerator* cg) {
3922 if (log() != NULL) {
3923 // The LogCompilation tool needs a unique way to identify late
3924 // inline call sites. This id must be unique for this call site in
3925 // this compilation. Try to have it unique across compilations as
3926 // well because it can be convenient when grepping through the log
3927 // file.
3928 // Distinguish OSR compilations from others in case CICountOSR is
3929 // on.
3930 jlong id = ((jlong)unique()) + (((jlong)compile_id()) << 33) + (CICountOSR && is_osr_compilation() ? ((jlong)1) << 32 : 0);
3931 cg->set_unique_id(id);
3932 log()->elem("inline_id id='" JLONG_FORMAT "'", id);
3933 }
3934 }
3935
3936 void Compile::log_inline_failure(const char* msg) {
3937 if (C->log() != NULL) {
3938 C->log()->inline_fail(msg);
3939 }
3940 }
3941
3942
3943 // Dump inlining replay data to the stream.
3944 // Don't change thread state and acquire any locks.
3945 void Compile::dump_inline_data(outputStream* out) {
3946 InlineTree* inl_tree = ilt();
3947 if (inl_tree != NULL) {
3948 out->print(" inline %d", inl_tree->count());
3949 inl_tree->dump_replay_data(out);
3950 }
3951 }
3952
3953 int Compile::cmp_expensive_nodes(Node* n1, Node* n2) {
3954 if (n1->Opcode() < n2->Opcode()) return -1;
3955 else if (n1->Opcode() > n2->Opcode()) return 1;
3956
3957 assert(n1->req() == n2->req(), err_msg_res("can't compare %s nodes: n1->req() = %d, n2->req() = %d", NodeClassNames[n1->Opcode()], n1->req(), n2->req()));
3958 for (uint i = 1; i < n1->req(); i++) {
3959 if (n1->in(i) < n2->in(i)) return -1;
3960 else if (n1->in(i) > n2->in(i)) return 1;
3961 }
3962
3963 return 0;
3964 }
3965
3966 int Compile::cmp_expensive_nodes(Node** n1p, Node** n2p) {
3967 Node* n1 = *n1p;
3968 Node* n2 = *n2p;
3969
3970 return cmp_expensive_nodes(n1, n2);
3971 }
3972
3973 void Compile::sort_expensive_nodes() {
3974 if (!expensive_nodes_sorted()) {
3975 _expensive_nodes->sort(cmp_expensive_nodes);
3976 }
3977 }
3978
3979 bool Compile::expensive_nodes_sorted() const {
3980 for (int i = 1; i < _expensive_nodes->length(); i++) {
3981 if (cmp_expensive_nodes(_expensive_nodes->adr_at(i), _expensive_nodes->adr_at(i-1)) < 0) {
3982 return false;
3983 }
3984 }
3985 return true;
3986 }
3987
3988 bool Compile::should_optimize_expensive_nodes(PhaseIterGVN &igvn) {
3989 if (_expensive_nodes->length() == 0) {
3990 return false;
3991 }
3992
3993 assert(OptimizeExpensiveOps, "optimization off?");
3994
3995 // Take this opportunity to remove dead nodes from the list
3996 int j = 0;
3997 for (int i = 0; i < _expensive_nodes->length(); i++) {
3998 Node* n = _expensive_nodes->at(i);
3999 if (!n->is_unreachable(igvn)) {
4000 assert(n->is_expensive(), "should be expensive");
4001 _expensive_nodes->at_put(j, n);
4002 j++;
4003 }
4004 }
4005 _expensive_nodes->trunc_to(j);
4006
4007 // Then sort the list so that similar nodes are next to each other
4008 // and check for at least two nodes of identical kind with same data
4009 // inputs.
4010 sort_expensive_nodes();
4011
4012 for (int i = 0; i < _expensive_nodes->length()-1; i++) {
4013 if (cmp_expensive_nodes(_expensive_nodes->adr_at(i), _expensive_nodes->adr_at(i+1)) == 0) {
4014 return true;
4015 }
4016 }
4017
4018 return false;
4019 }
4020
4021 void Compile::cleanup_expensive_nodes(PhaseIterGVN &igvn) {
4022 if (_expensive_nodes->length() == 0) {
4023 return;
4024 }
4025
4026 assert(OptimizeExpensiveOps, "optimization off?");
4027
4028 // Sort to bring similar nodes next to each other and clear the
4029 // control input of nodes for which there's only a single copy.
4030 sort_expensive_nodes();
4031
4032 int j = 0;
4033 int identical = 0;
4034 int i = 0;
4035 for (; i < _expensive_nodes->length()-1; i++) {
4036 assert(j <= i, "can't write beyond current index");
4037 if (_expensive_nodes->at(i)->Opcode() == _expensive_nodes->at(i+1)->Opcode()) {
4038 identical++;
4039 _expensive_nodes->at_put(j++, _expensive_nodes->at(i));
4040 continue;
4041 }
4042 if (identical > 0) {
4043 _expensive_nodes->at_put(j++, _expensive_nodes->at(i));
4044 identical = 0;
4045 } else {
4046 Node* n = _expensive_nodes->at(i);
4047 igvn.hash_delete(n);
4048 n->set_req(0, NULL);
4049 igvn.hash_insert(n);
4050 }
4051 }
4052 if (identical > 0) {
4053 _expensive_nodes->at_put(j++, _expensive_nodes->at(i));
4054 } else if (_expensive_nodes->length() >= 1) {
4055 Node* n = _expensive_nodes->at(i);
4056 igvn.hash_delete(n);
4057 n->set_req(0, NULL);
4058 igvn.hash_insert(n);
4059 }
4060 _expensive_nodes->trunc_to(j);
4061 }
4062
4063 void Compile::add_expensive_node(Node * n) {
4064 assert(!_expensive_nodes->contains(n), "duplicate entry in expensive list");
4065 assert(n->is_expensive(), "expensive nodes with non-null control here only");
4066 assert(!n->is_CFG() && !n->is_Mem(), "no cfg or memory nodes here");
4067 if (OptimizeExpensiveOps) {
4068 _expensive_nodes->append(n);
4069 } else {
4070 // Clear control input and let IGVN optimize expensive nodes if
4071 // OptimizeExpensiveOps is off.
4072 n->set_req(0, NULL);
4073 }
4074 }
4075
4076 /**
4077 * Remove the speculative part of types and clean up the graph
4078 */
4079 void Compile::remove_speculative_types(PhaseIterGVN &igvn) {
4080 if (UseTypeSpeculation) {
4081 Unique_Node_List worklist;
4082 worklist.push(root());
4083 int modified = 0;
4084 // Go over all type nodes that carry a speculative type, drop the
4085 // speculative part of the type and enqueue the node for an igvn
4086 // which may optimize it out.
4087 for (uint next = 0; next < worklist.size(); ++next) {
4088 Node *n = worklist.at(next);
4089 if (n->is_Type()) {
4090 TypeNode* tn = n->as_Type();
4091 const Type* t = tn->type();
4092 const Type* t_no_spec = t->remove_speculative();
4093 if (t_no_spec != t) {
4094 bool in_hash = igvn.hash_delete(n);
4095 assert(in_hash, "node should be in igvn hash table");
4096 tn->set_type(t_no_spec);
4097 igvn.hash_insert(n);
4098 igvn._worklist.push(n); // give it a chance to go away
4099 modified++;
4100 }
4101 }
4102 uint max = n->len();
4103 for( uint i = 0; i < max; ++i ) {
4104 Node *m = n->in(i);
4105 if (not_a_node(m)) continue;
4106 worklist.push(m);
4107 }
4108 }
4109 // Drop the speculative part of all types in the igvn's type table
4110 igvn.remove_speculative_types();
4111 if (modified > 0) {
4112 igvn.optimize();
4113 }
4114 #ifdef ASSERT
4115 // Verify that after the IGVN is over no speculative type has resurfaced
4116 worklist.clear();
4117 worklist.push(root());
4118 for (uint next = 0; next < worklist.size(); ++next) {
4119 Node *n = worklist.at(next);
4120 const Type* t = igvn.type_or_null(n);
4121 assert((t == NULL) || (t == t->remove_speculative()), "no more speculative types");
4122 if (n->is_Type()) {
4123 t = n->as_Type()->type();
4124 assert(t == t->remove_speculative(), "no more speculative types");
4125 }
4126 uint max = n->len();
4127 for( uint i = 0; i < max; ++i ) {
4128 Node *m = n->in(i);
4129 if (not_a_node(m)) continue;
4130 worklist.push(m);
4131 }
4132 }
4133 igvn.check_no_speculative_types();
4134 #endif
4135 }
4136 }
4137
4138 // Auxiliary method to support randomized stressing/fuzzing.
4139 //
4140 // This method can be called the arbitrary number of times, with current count
4141 // as the argument. The logic allows selecting a single candidate from the
4142 // running list of candidates as follows:
4143 // int count = 0;
4144 // Cand* selected = null;
4145 // while(cand = cand->next()) {
4146 // if (randomized_select(++count)) {
4147 // selected = cand;
4148 // }
4149 // }
4150 //
4151 // Including count equalizes the chances any candidate is "selected".
4152 // This is useful when we don't have the complete list of candidates to choose
4153 // from uniformly. In this case, we need to adjust the randomicity of the
4154 // selection, or else we will end up biasing the selection towards the latter
4155 // candidates.
4156 //
4157 // Quick back-envelope calculation shows that for the list of n candidates
4158 // the equal probability for the candidate to persist as "best" can be
4159 // achieved by replacing it with "next" k-th candidate with the probability
4160 // of 1/k. It can be easily shown that by the end of the run, the
4161 // probability for any candidate is converged to 1/n, thus giving the
4162 // uniform distribution among all the candidates.
4163 //
4164 // We don't care about the domain size as long as (RANDOMIZED_DOMAIN / count) is large.
4165 #define RANDOMIZED_DOMAIN_POW 29
4166 #define RANDOMIZED_DOMAIN (1 << RANDOMIZED_DOMAIN_POW)
4167 #define RANDOMIZED_DOMAIN_MASK ((1 << (RANDOMIZED_DOMAIN_POW + 1)) - 1)
4168 bool Compile::randomized_select(int count) {
4169 assert(count > 0, "only positive");
4170 return (os::random() & RANDOMIZED_DOMAIN_MASK) < (RANDOMIZED_DOMAIN / count);
4171 }